Backpack-type work machine

Abstract

To provide a backpack type working machine which suppresses breakage of a body housing when the backpack type working machine collides with a mounting surface.SOLUTION: A backpack type working machine comprises: a discharge pipe which discharges liquid; a body unit with a battery and a body housing which supports the battery; and an elastically deformable flame unit which supports the body housing. The body unit includes a counterface surface facing a back of a user when the user carries the backpack type working machine on his / her back. The frame unit includes a pair of side frames. The pair of side frames are arranged outside of the body housing in a right and left direction when a direction orthogonal to a mounting surface is a vertical direction in a case that the backpack type working machine is placed on the mounting surface, when a direction orthogonal to the counterface surface is a front-back direction, and when a direction orthogonal to the vertical direction and the front-back direction is the right and left direction.SELECTED DRAWING: Figure 19

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a backpack-type work machine. [Background technology]

[0002] Patent Document 1 discloses a backpack-type working machine that discharges liquid. The backpack-type working machine includes a main unit that includes a discharge pipe for discharging the liquid, an engine, a centrifugal fan, and a main housing that supports the engine and the centrifugal fan, and a frame unit that supports the main housing. The frame unit includes side frames. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] German Patent Invention No. 102004052649 Summary of the Invention [Problem to be solved by the invention]

[0004] In the backpack-type work machine described above, the main body housing supports the centrifugal fan, which increases the size of the main body housing in the left-right direction. In the case of an engine-powered backpack-type work machine, the main body housing is typically positioned further outward than the frame unit in the left-right direction. When a main body housing positioned further outward than the frame unit is used in an electric backpack-type work machine, if the electric backpack-type work machine falls and hits a support surface such as the ground, the main body unit hits the support surface first. This results in damage to the main body housing. This specification provides a technology that can prevent damage to the main body housing when the electric backpack-type work machine hits a support surface. [Means for solving the problem]

[0005] This specification discloses a backpack-type working machine. The backpack-type working machine includes a main unit including a discharge pipe for discharging a liquid, a battery, and a main housing for supporting the battery, and an elastically deformable frame unit that supports the main housing. The main unit has an opposing surface that faces the user's back when the backpack-type working machine is carried on the user's back. The frame unit includes a pair of side frames. When the backpack-type working machine is placed on a mounting surface, the direction perpendicular to the mounting surface is defined as the up-down direction, the direction perpendicular to the opposing surface is defined as the front-back direction, and the direction perpendicular to the up-down direction and the front-back direction is defined as the left-right direction, the pair of side frames are positioned outward of the main housing in the left-right direction.

[0006] With the above configuration, when the backpack-type work machine falls and the left or right end of the main unit hits the support surface, the side frames elastically deform before the main housing hits the support surface. This allows the side frames to absorb the impact of the fall, thereby preventing damage to the main housing. [Brief explanation of the drawings]

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

[0008] Representative, non-limiting embodiments of the present invention are described in detail below with reference to the drawings. This detailed description is intended simply to provide those skilled in the art with details for implementing preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Furthermore, the additional features and inventions disclosed can be used separately or in conjunction with other features and inventions to provide further improved backpack-type work machines.

[0009] Furthermore, the combinations of features and steps disclosed in the following detailed description are not essential to practicing the invention in its broadest sense, but are described solely to specifically illustrate exemplary embodiments of the invention. Furthermore, the various features of the following exemplary embodiments and those described in the claims do not necessarily have to be combined in the exact embodiments described herein or in the exact order listed to provide additional and useful embodiments of the invention.

[0010] All features described in this specification and / or claims are intended to be disclosed individually and independently of one another as limitations to the specific features described in the original disclosure and claims, apart from the configuration of features described in the examples and / or claims. Furthermore, all numerical ranges and group or aggregate descriptions are intended to disclose intermediate configurations thereof as limitations to the specific features described in the original disclosure and claims.

[0011] In one or more embodiments, the frame unit may include a rear frame that is disposed rearward of the main body housing in the front-to-rear direction.

[0012] With the above configuration, when the backpack-type work machine falls and the rear end of the main unit hits the support surface, the rear frame elastically deforms before the main housing hits the support surface, allowing the rear frame to absorb the impact of the fall and preventing damage to the main housing.

[0013] In one or more embodiments, the frame unit may include a lower frame disposed below the main body housing.

[0014] With the above configuration, when the backpack-type work machine falls and the lower end of the main unit hits the support surface, the lower frame elastically deforms before the main housing hits the support surface, allowing the lower frame to absorb the impact of the fall and preventing damage to the main housing.

[0015] In one or more embodiments, the main body housing may have a lower facing surface that faces the lower frame. The lower facing surface may have a curved shape that is convex toward the lower frame.

[0016] With the above configuration, when the backpack-type working machine collides with the mounting surface and the lower frame elastically deforms, the lower frame abuts against the lower opposing surface of the main housing. The lower frame then elastically deforms to conform to the shape of the lower opposing surface, thereby absorbing the impact of the fall.

[0017] In one or more embodiments, the pair of side frames may be positioned outward from the battery.

[0018] With the above configuration, when the backpack-type work machine falls and hits the support surface, the side frames elastically deform before the main housing hits the support surface, thereby absorbing the impact of the fall and protecting the battery.

[0019] In one or more embodiments, the main unit may further include a liquid tank that stores the liquid to be discharged from the discharge pipe.

[0020] According to the above configuration, when liquid is stored in the liquid tank, the backpack-type working machine becomes heavy. Even when a heavy backpack-type working machine falls and strikes the support surface from the left or right end of the main unit, the side frames elastically deform before the main housing strikes the support surface. This allows the side frames to absorb the impact of the fall. This makes it possible to prevent damage to the main housing even with a heavy backpack-type working machine.

[0021] In one or more embodiments, at least a portion of the liquid tank may be disposed above the main body housing. The liquid tank may include a receiving groove that receives the frame unit. The frame unit may be received in the receiving groove and support the liquid tank from below.

[0022] With the above configuration, the frame unit supports the liquid tank from below, so when the backpack-type work machine falls and hits the support surface, the frame unit can absorb part of the external force acting on the main housing from the liquid tank, thereby preventing damage to the main housing.

[0023] (Example) As shown in FIG. 1 , the work machine 2 is a backpack-type work machine. The work machine 2 is configured to release (spray) a liquid. The work machine 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 work machine 2 includes a main body 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 body unit 4. The harness unit 8 is attached directly and / or indirectly to the main body unit 4. The discharge pipe 10 is attached to the lower right side of the main body unit 4. The handle unit 12 is attached to the discharge pipe 10. A user wearing the harness unit 8 and carrying the work machine 2 on their back grasps the handle unit 12 and moves the discharge pipe 10 to spray liquid from the discharge pipe 10. 2, the main unit 4 has a facing surface 4a that faces the back of the user when the work machine 2 is carried on the user's back. Hereinafter, when the work machine 2 is placed on a placement surface P such as the ground, the direction perpendicular to the facing surface 4a will be referred to as the front-to-rear direction, the direction perpendicular to the placement surface P will be referred to as the up-to-down direction, and the direction perpendicular to the front-to-rear direction and the up-to-down direction will be referred to as the left-to-right direction.

[0024] As shown in Fig. 3, the main body unit 4 includes a main body housing 16, a fan unit 18, a control unit 20, a battery unit 22, and a liquid tank 24. The main body housing 16 supports the fan unit 18, the battery unit 22, and the liquid tank 24. The main body housing 16 includes a front main body housing 26 and a rear main body housing 28. As shown in Fig. 2, the front main body housing 26 includes a facing surface 30 that faces the user's back when the work implement 2 is carried on the user's back. The facing surface 30 forms part of the facing surface 4a of the main body unit 4.

[0025] As shown in Fig. 4, the rear main body housing 28 includes 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 rotation axis extending in the left-right direction. The rotation axis of the cover portion 34 is located above the battery unit 22. The cover portion 34 is located behind the battery unit 22.

[0026] As shown in FIGS. 3 and 4 , a first internal space 36 and a second internal space 38 are defined between the front main body housing 26 and the rear main body housing 28. The fan unit 18 and the control unit 20 are disposed in the first internal space 36. A cover 40 is attached near the lower left side of the main body housing 16, and the first internal space 36 communicates with the outside of the work machine 2 via an air intake port 40a of the cover 40. The second internal space 38 is disposed above the first internal space 36. The second internal space 38 is separated from the first internal space 36. The battery unit 22 is disposed in the second internal space 38. Therefore, a battery pack BP (described later) is disposed in the second internal space 38. By opening the cover portion 34 upward, the second internal space 38 communicates with the outside of the work machine 2.

[0027] 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 arranged above the fan unit 18, and the liquid tank 24 is arranged above the battery unit 22. As shown in FIG. 5, when the work machine 2 is placed on the placement surface P (see FIG. 2) and viewed from above, at least 50% or more of the liquid tank 24 overlaps with each of the fan unit 18 and the battery unit 22. In FIG. 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 dashed line. Furthermore, at least 50% or more of the fan unit 18 overlaps with each of the battery unit 22 and the liquid tank 24. Furthermore, at least 50% or more of the battery unit 22 overlaps with each of the fan unit 18 and the liquid tank 24.

[0028] 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 located at center of gravity G1. When two battery packs BP are disposed in the second internal space 38, the center of gravity of the battery unit 22 is located at center of gravity G2, and when two battery packs BP are not disposed in the second internal space 38, the center of gravity of the battery unit 22 is located at center of gravity G3. When the liquid tank 24 is filled to its maximum capacity with liquid, the center of gravity of the liquid tank 24 is located at center of gravity G4, and when no liquid is stored in the liquid tank 24, the center of gravity of the liquid tank 24 is located at center of gravity G5. Furthermore, when two battery packs BP are arranged 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, and when two battery packs BP are arranged in the second internal space 38 and no liquid is stored in the liquid tank 24, the center of gravity of the main unit 4 is at center of gravity position G7.

[0029] 2, the centers of gravity G2 and G3 of the battery unit 22 are substantially the same in the front-to-rear direction and the up-to-down direction. The center of gravity G4 of the liquid tank 24 is substantially the same as the center of gravity G5 in the front-to-rear direction and is located slightly below the center of gravity G5 in the up-to-down direction. The center of gravity G6 of the main body unit 4 is located slightly behind the center of gravity G7 in the front-to-rear direction and is located above the center of gravity G7 in the up-to-down direction.

[0030] In the front-to-rear direction, the center of gravity G1 of the fan unit 18, the centers G2 and G3 of the battery unit 22, the centers G4 and G5 of the liquid tank 24, and the centers G6 and G7 of the main body unit 4 are located in an area that is 1 / 3 of the width of the main body unit 4 in the front-to-rear direction (in this embodiment, an area that is 1 / 6 of the width of the main body unit 4 in the front-to-rear direction). In FIG. 2, the area that is 1 / 3 of the width of the main body unit 4 in the front-to-rear direction is indicated by a dashed line. The center of gravity G1 is located near a center position CP1 of the main body unit 4 in the front-to-rear direction. The centers of gravity G2, G3, G4, G5, G6, and G7 are located closer to the opposing surface 4a (front side) than the center position CP1. The center position CP1 is located in the center between the front and rear ends of the main body unit 4. In FIG. 2, the center position CP1 is indicated by a dashed line.

[0031] 6, the positions of the centers of gravity G2 and G3 of the battery unit 22 are substantially the same in the left-right direction. The positions of the centers of gravity G4 and G5 of the liquid tank 24 are substantially the same in the left-right direction. The position of the center of gravity G6 of the main body unit 4 is located farther from the discharge pipe 10 (to the left) than the position of the center of gravity G7 in the left-right direction.

[0032] In the left-right direction, the center of gravity G1 of the fan unit 18, the centers of gravity G2 and G3 of the battery unit 22, the centers of gravity G4 and G5 of the liquid tank 24, and the centers of gravity G6 and G7 of the main body unit 4 are located in an area that is 1 / 3 of the left-right width of the main body unit 4 (in this embodiment, an area that is 1 / 6 of the left-right width of the main body unit 4). In FIG. 6, the area that is 1 / 3 of the left-right width of the main body unit 4 is illustrated by a dashed line. The centers of gravity G1, G6, and G7 are located closer to the discharge pipe 10 (to the right) than the center position CP2 of the main body unit 4 in the left-right direction. The centers of gravity G2, G3, G4, and G5 are located near the center position CP2 of the main body unit 4 in the left-right direction. The center position CP2 is located in the center between the right and left ends of the main body unit 4. In FIG. 6, the center position CP2 is illustrated by a dashed line.

[0033] As shown in FIG. 7 , the fan unit 18 includes a fan 44, an electric motor 46, a motor housing 48, a cover member 50, a cone 52, and a tubular member 54. The fan 44 is, for example, an axial fan. A 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. A plurality of rectifying 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 tubular member 54 has a substantially cylindrical shape. The tubular 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 tubular member 54 is connected to the plurality of rectifying fins 55. The cylindrical member 54 is supported by the main body housing 16 (see FIG. 3).

[0034] The control unit 20 is attached to the upper part of the cylindrical member 54. The control unit 20 includes a control board 56 equipped with a plurality of switching elements (not shown) and a microcomputer. 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 covers 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.

[0035] The discharge pipe 10 shown in FIG. 1 is attached to the tubular member 54. The discharge pipe 10 is disposed on the right side of the main unit 4. The discharge pipe 10 includes a curved pipe 60 attached to the tubular member 54 (see FIG. 3), a bellows tube 62 attached to the curved pipe 60, an intermediate pipe 64 attached to the bellows tube 62, and a tip pipe 66 attached to the intermediate pipe 64. The bellows tube 62 is configured so that the orientations of the intermediate pipe 64 and the tip pipe 66 can be adjusted. As shown in FIG. 8, a dome-shaped diffusion cover 70 is attached to the tip of the tip pipe 66.

[0036] A handle unit 12 is attached to the intermediate tube 64. The handle unit 12 includes a grip portion 72 that is held by the user, a trigger 74 attached to the grip portion 72, and a head portion 76 connected to the grip portion 72. The user can adjust the orientation of the intermediate tube 64 and the tip tube 66 by holding the grip portion 72 and moving the handle unit 12. The user can also press the trigger 74 with the fingers of the hand holding the grip portion 72. When the trigger 74 is pressed, a signal is sent to the control board 56 (see FIG. 7).

[0037] As shown in FIG. 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 a user's operation to switch the work machine 2 between an on state and an off state. The user operates the main power button 78 with the fingers of the hand holding the grip unit 72. When the main power button 78 is operated, a signal is sent to the control board 56 (see FIG. 7 ). The adjustment button 80 is located on the top surface of the head unit 76. The adjustment button 80 accepts a user's operation to adjust the rotation speed of the electric motor 46 (see FIG. 7 ). The user can operate the adjustment button 80 with the fingers of the hand opposite the hand holding the grip unit 72. When the adjustment button 80 is operated, a signal is sent to the control board 56.

[0038] When the trigger 74 is pressed by a user while the work implement 2 is in the on state, as shown in FIG. 7, the control board 56 rotates the shaft 46a of the electric motor 46, causing the fan 44 to rotate. As a result, as shown in FIG. 3, air flows from the outside of the work implement 2 into the first internal space 36 through the multiple air intakes 40a (see FIG. 4). The inflowing air then flows into the tubular member 54. As shown in FIG. 7, the inflowing air is blown out by the fan 44, straightened by the multiple straightening fins 55, and then flows along the cone 52. Because at least a portion of the lower surface of the case 57 covers the opening 54a of the tubular member 54, the air blown out by the fan 44 flows along the lower surface of the case 57. This cools the case 57, and as a result, cools the control unit 20 (control board 56). The air then flows through the inside of the discharge pipe 10 shown in FIG. 8, passes through the diffusion cover 70, and is discharged to the outside of the work implement 2. The air is guided radially outward of the tip tube 66 by the diffusion fins 70a of the diffusion cover 70 and is released over a wide area.

[0039] As shown in Figures 3 and 4, the battery unit 22 is disposed above the fan unit 18 and the control unit 20. The battery unit 22 includes a right-side battery mounting portion 84, a left-side battery mounting portion 86, and multiple (two in this embodiment) battery packs BP. The right-side battery mounting portion 84 and the left-side battery mounting portion 86 are aligned in the left-right direction. A center wall 88 is disposed in the second internal space 38, with the right-side battery mounting portion 84 disposed on the right surface of the center wall 88 and the left-side battery mounting portion 86 disposed on the left surface of the center wall 88. The center wall 88 is disposed at the center of the second internal space 38 in the left-right direction. The center wall 88 is disposed on a plane that is aligned along the up-down direction and the front-rear direction.

[0040] The battery pack BP can be attached to and detached from either the right battery mounting portion 84 or the left battery mounting portion 86 when the cover portion 34 is open. The battery pack BP can be attached to and detached from either the right battery mounting portion 84 or the left battery mounting portion 86 by sliding the battery pack BP forward and backward. The battery pack BP includes, for example, a lithium-ion battery. The power of the battery pack BP can be supplied to the electric motor 46 (see FIG. 7). When the battery pack BP is attached to both the right battery mounting portion 84 and the left battery mounting portion 86, power is first 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 of the right battery pack BP becomes zero, power is supplied to the electric motor 46 from the left battery pack BP. In this state, when the right battery pack BP, whose remaining power is zero, is removed from the right battery mounting portion 84, the center of gravity positions G6, G7 (see FIG. 6) of the main unit 4 move in a direction (left side) away from the discharge pipe 10. When the work implement 2 is carried on the user's back, the work implement 2 is prevented from tilting toward the discharge pipe 10.

[0041] The liquid tank 24 is disposed above the battery unit 22. As shown in FIG. 9, the liquid tank 24 includes a tank body 90, a protrusion 92, a filter unit 94, and a tank cap 96. The tank body 90 stores liquid to be discharged (sprayed). The capacity of the tank body 90 is, for example, 10 L or more, and in this embodiment, is 15 L. The tank body 90 includes a facing surface 90a that faces the user's back when the work implement 2 is carried on the user's back. The facing surface 90a forms part of the facing surface 4a (see FIG. 2) of the main unit 4.

[0042] A first engagement groove 98 and a second engagement groove 100 are formed near the lower part of the 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 FIG. 10 , a third engagement groove 102 and a fourth engagement groove 104 are formed near the lower part of the 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. A first engagement wall 106, a second engagement wall 108, a third engagement wall 110, and a fourth engagement wall 112 are formed in the body housing 16. When the tank body 90 is sandwiched between the front body housing 26 and the rear body housing 28, the first engagement wall 106 engages with the first engagement groove 98, the second engagement wall 108 engages with the second engagement groove 100, the third engagement wall 110 engages with the third engagement groove 102, and the fourth engagement wall 112 engages with the fourth engagement groove 104. This causes the lower part of the tank body 90 to be fixed to the main body housing 16 inside the main body housing 16. As shown in FIG. 1 , when the tank body 90 is fixed to the main body housing 16, the upper part of the tank body 90 is disposed above the main body housing 16.

[0043] As shown in FIG. 11, a discharge portion 90b and a supply portion 90c are formed at the bottom end of the tank body 90. A discharge tube 91 is connected to the discharge portion 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 via the discharge portion 90b and the discharge tube 91. A supply line 113 is connected to the supply portion 90c. The supply line 113 will be described in detail later.

[0044] As shown in FIG. 9, the protrusion 92 is connected to the upper surface (upper portion) of the tank body 90. When the work machine 2 is placed on the placement surface P (see FIG. 2), the protrusion 92 is positioned higher than the upper surface of the tank body 90. The protrusion 92 has a side wall 114 having a substantially cylindrical 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 protrusion 92, and the protrusion 92 is configured by the side wall 114. The supply port 116 is an opening for supplying liquid to the inside of the tank body 90. A plurality of ribs 118 are formed on the inner surface of the side wall 114. The plurality of ribs 118 extend radially inward of the side wall 114.

[0045] The side wall 114 includes a first side portion 120 and a second side portion 122. The first side portion 120 has a generally cylindrical shape. The first side portion 120 includes an engaged rail 124 disposed on the outer surface of the first side portion 120. The engaged rail 124 extends spirally along the circumferential direction of the outer surface of the first side portion 120. The engaged rail 124 is partially interrupted in the circumferential direction of the outer surface of the first side portion 120.

[0046] The second side portion 122 is connected to the first side portion 120. The outer surface of the second side portion 122 has a flat shape. In a modified example, the outer surface of the second side portion 122 may have a curved shape. The outer surface of the second side portion 122 does not have an engaged rail 124 formed thereon in the circumferential direction of the side wall 114. As shown in FIG. 12 , the outer surface of the second side portion 122 is recessed radially inward of 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 spaced apart 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.

[0047] 9, a plurality of (six in this embodiment) communication holes 126 are formed in the second side portion 122. The plurality of communication holes 126 penetrate the second side portion 122 in the thickness direction.

[0048] The filter unit 94 includes a base member 128, a filter 130, fins 132, and a handle 133. The base member 128 includes a first cylindrical portion 134 having a generally cylindrical shape and a second cylindrical portion 136 having a larger diameter than the first cylindrical portion 134. The first cylindrical portion 134 supports the filter 130. The filter 130 is disposed 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 the liquid is supplied to the inside of the tank body 90. The second cylindrical portion 136 is connected to the upper end of the first cylindrical portion 134. As shown in FIG. 13 , when the filter unit 94 is attached to the protruding portion 92, the lower end of the second cylindrical portion 136 rests on the plurality of ribs 118.

[0049] 9, the fins 132 are connected to the lower end of the first cylindrical portion 134. The handle 133 is connected to the first cylindrical portion 134. When a user grips the handle 133 and rotates the filter unit 94, the fins 132 rotate, thereby agitating the liquid inside the tank body 90.

[0050] The tank cap 96 can close the supply port 116 in the side wall 114 from above. The tank cap 96 has a generally cylindrical shape with a bottom wall at the upper end. As shown in FIG. 13 , the tank cap 96 has an engaging rail 140 disposed on the inner surface of the tank cap 96. The engaging rail 140 extends spirally along the circumferential direction of the inner surface of the tank cap 96. When the tank cap 96 closes the supply port 116 in the side wall 114, the engaging rail 140 engages with the engaged rail 124.

[0051] As shown in FIG. 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 provide communication between the interior of the liquid tank 24 and the outside of the work machine 2. A communication space 142 is defined between the tank cap 96 and the side wall 114. The width of the communication space 142, i.e., 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 is in direct communication with the multiple communication holes 126. The communication space 142 is in direct communication with the outside of the work machine 2 at its lower end.

[0052] The liquid tank 24 further includes 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, such as a rubber material in this embodiment. The one-way valve 144 includes 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 disk shape. The valve portion 148 is elastically deformable. The valve portion 148 is disposed inside the liquid tank 24, between the second side portion 122 and the base member 128. The valve portion 148 is able to abut against the inner surface of the second side portion 122. The valve portion 148 abuts against the inner surface of the second side portion 122, thereby prohibiting 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 plurality of communication holes 126. Furthermore, the valve portion 148 moves away from the inner surface of the second side portion 122, thereby allowing fluid to flow from the outside of the work machine 2 to the inside of the liquid tank 24 through the plurality of communication holes 126.

[0053] The valve portion 148 normally abuts against the inner surface of the second side portion 122, for example, when the work machine 2 is not in use. This blocks the multiple communication holes 126, and the interior of the liquid tank 24 is not in communication with the outside of the work machine 2 via the multiple communication holes 126. When the work machine 2 is in use, for example, when the work machine 2 is used to spray liquid from the discharge pipe 10 (see FIG. 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 the discharge tube 91, the amount of liquid in the tank body 90 decreases. This increases the volume of the void in the liquid tank 24. Because the interior of the liquid tank 24 is not in communication with the outside of the work machine 2, the pressure in the void in the liquid tank 24 decreases. As shown in FIG. 15 , when the pressure in the void in the liquid tank 24 becomes lower than the pressure outside the work machine 2 (atmospheric pressure), the valve portion 148 elastically deforms and moves away from the inner surface of the second side portion 122. As a result, as shown in Figure 15 as air flow AF, air outside the work machine 2 flows from the underside of the tank cap 96 into the communication space 142, passes through the communication space 142 and the multiple communication holes 126, and flows into the interior of the liquid tank 24. This increases the pressure in the voids within the liquid tank 24. This can prevent a situation in which a drop in pressure in the voids within the liquid tank 24 makes it difficult for the liquid within the liquid tank 24 to be supplied toward the discharge pipe 10, or makes it difficult for the liquid within the liquid tank 24 to be discharged to the outside of the liquid tank 24 via the discharge portion 90b and the discharge tube 91.

[0054] The frame unit 6 shown in FIG. 16 is fixed to the main body unit 4 (see FIG. 1). The frame unit 6 includes a pair of side frames 170, 172, a rear frame 174, a top frame 176, a lower frame 178, a first fixed frame 180, and a second fixed frame 182. Hereinafter, the pair of side frames 170, 172 may be referred to as the right-side frame 170 and the left-side frame 172. Each of the frames 170, 172, 174, 176, 178, 180, and 182 is made of a metal material, such as aluminum. Each of the frames 170, 172, 174, 176, 178, 180, and 182 is elastically deformable when subjected to an external force.

[0055] The right side frame 170 includes 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 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.

[0056] The left-side frame 172 is disposed to the left of the right-side frame 170. The left-side frame 172 includes 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 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.

[0057] 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, 172. The rear frame 174 extends in the left-right direction. A third contact member 188 is attached to the connection between the rear frame 174 and the third right-side frame 170c. A fourth contact member 190 is attached to the connection 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, such as polypropylene. As shown in FIG. 2, when the work implement 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 come into contact with the mounting surface P.

[0058] 16, the top frame 176 is connected to the first right-side frame 170a and the first left-side frame 172a with screws. The top frame 176 extends rearward from the rear end of the first right-side frame 170a, then bends and extends to the left, and then bends and extends forward to the rear end of the first left-side frame 172a.

[0059] 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 disposed between the third right side frame 170c and the third left side frame 172c. The lower frame 178 is disposed forward of the rear frame 174. The lower frame 178 extends in the left-right direction.

[0060] The first fixing frame 180 is connected to the second right-side frame 170b and the second left-side frame 172b. The first fixing frame 180 extends in the left-right direction. The second fixing frame 182 is connected to the second right-side frame 170b and the second left-side frame 172b below the first fixing frame 180. The second fixing frame 182 extends in the left-right direction.

[0061] As shown in FIG. 17 , a first fixing groove 192 and a second fixing groove 194 are formed in the opposing surface 30 of the main body housing 16. The first fixing groove 192 and the second fixing groove 194 are recessed rearward 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 FIG. 18 , the first fixing frame 180 is received in the first fixing groove 192 and fixed to the main body housing 16 with screws. The upper surface of the first fixing frame 180 abuts against the upper surface of the first fixing groove 192 of the main body housing 16. Furthermore, when the first fixing frame 180 is received in the first fixing groove 192, the entire first fixing frame 180 is positioned rearward of the opposing surface 30 in the front-rear direction. The second fixed frame 182 is received in the second fixed groove 194 and fixed to the main body housing 16 with screws. The upper surface of the second fixed frame 182 abuts against the upper surface of the second fixed groove 194 of the main body housing 16. Furthermore, when the second fixed frame 182 is received in the second fixed groove 194, the entire second fixed frame 182 is positioned rearward of the opposing surface 30 in the front-to-rear direction. This prevents the first fixed frame 180 and the second fixed frame 182 from coming into contact with the user's back when the user carries the work machine 2 on their back.

[0062] 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 and extends leftward from the right end to the left end of the tank body 90, and then bends and extends 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.

[0063] The positional relationship between the main body unit 4 and the frame unit 6 when the frame unit 6 is fixed to the main body unit 4 will be described. As shown in FIG. 19, the second right-side frame 170b is disposed to the right (outside) of the main body housing 16 in the left-right direction. The second left-side frame 172b is disposed to the left (outside) of the main body housing 16. That is, the main body housing 16 is disposed between the second right-side frame 170b and the second left-side frame 172b. Therefore, the battery unit 22 (see FIG. 3) and the fan unit 18 (see FIG. 3), for example, the battery pack BP (see FIG. 3) and the electric motor 46 (see FIG. 7), are disposed between the second right-side frame 170b and the second left-side frame 172b.

[0064] In the vertical direction, the top frame 176 is disposed above (outside) the main body housing 16. The rear frame 174 is disposed below (outside) the main body housing 16. That is, the main body housing 16 is disposed between the top frame 176 and the rear frame 174. Therefore, the battery unit 22 and the fan unit 18, for example, the battery pack BP and the electric motor 46, are also disposed between the top frame 176 and the rear frame 174.

[0065] 5, in the front-rear direction, the rear frame 174 is disposed rearward (outward) from the main body housing 16. Therefore, the rear frame 174 is disposed rearward from the battery unit 22 and the fan unit 18, for example, from the battery pack BP and the electric motor 46.

[0066] As shown in Figure 20, the lower frame 178 is disposed below (outside) the main body housing 16. The lower frame 178 faces a lower opposing surface 200 of the main body housing 16. The lower opposing surface 200 forms the lower surface of the main body housing 16. The lower opposing surface 200 has a curved shape that convex downward toward the lower frame 178. In the left-right direction, the center of the lower opposing surface 200 is disposed closest to the lower frame 178, and both end portions of the lower opposing surface 200 are disposed furthest from the lower frame 178.

[0067] When the work machine 2 falls and collides with the placement surface P from the lower end side, at least one of the contact members 184, 186, 188, 190 collides with the placement surface P first. As a result, before the main body housing 16 collides with the placement surface P, the third right-side frame 170c (see FIG. 16) and / or the third left-side frame 172c (see FIG. 16) and / or the rear frame 174 (see FIG. 16) elastically deform. Thereafter, the lower frame 178 abuts against the lower opposing surface 200, and the lower frame 178 elastically deforms to match the shape of the lower opposing surface 200. As a result, the impact caused by the fall is absorbed by the lower frame 178, and damage to the main body housing 16 is suppressed.

[0068] As shown in FIG. 18 , the harness unit 8 is attached to the main unit 4. The harness unit 8 includes 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 body housing 16. The pad 204 is disposed in a position facing the first fixing groove 192 of the main body 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 disposed below the pad 204. The waist belt 206 is disposed in a position facing the second fixing groove 194 of the main body housing 16. The waist belt 206 is worn around the user's waist when the user carries the work machine 2 on their back.

[0069] 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 on 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 positioned lower than 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.

[0070] 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 on 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 disposed 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.

[0071] As shown in FIG. 21 , in the left-right direction, a center position CP3 between the first upper mounting portion 214 and the second upper mounting portion 218 is located closer to the discharge pipe 10 (to the right) than a center position CP2 of the main body 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 FIG. 21 , the center position CP2 is illustrated by a dashed line, and the center position CP3 is illustrated by a dashed 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 FIG. 3) are disposed in the second internal space 38 (see FIG. 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 G6, and the center of gravity of the work implement 2 is at first overall center of gravity G8. Furthermore, when two battery packs BP are disposed in the second internal space 38 and no liquid is stored in the liquid tank 24, the center of gravity of the main unit 4 is at center of gravity G7, and the center of gravity of the work implement 2 is at second overall center of gravity G9. In the left-right direction, the centers of gravity G6, G7, the first overall center of gravity G8, and the second overall center of gravity G9 are located between the first upper mounting part 214 and the second upper mounting part 218. The centers of gravity G6, G7, the first overall center of gravity G8, and the second overall center of gravity G9 are located closer to the discharge pipe 10 (to the right) than 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 farther away from the center of gravity position G7 than the center position CP3. In 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.That is, the distance in the left-right direction from the center position CP3 to the first overall center-of-gravity position G8 is approximately equal to the distance in the left-right direction from the center position CP3 to the second overall center-of-gravity position G9.

[0072] Next, the supply line 113 will be described. As shown in FIGS. 8 and 11, the supply line 113 includes 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 performing work, the first supply cock 232, the second supply cock 238, and the third supply cock 242 are open. As shown in FIG. 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 a metal material. The first supply cock 232 and the solenoid valve 234 are disposed on the first supply pipe 230. The first supply cock 232 is operated by the user's hand. The first supply cock 232 opens and closes the first supply pipe 230. Although not shown, the solenoid valve 234 is disposed inside the main body housing 16 (see FIG. 3). The solenoid valve 234 is electrically connected to the control board 56 (see FIG. 7). The solenoid valve 234 opens and closes under the control of the control board 56.

[0073] 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 FIG. 8, the supply tube 236 extends along the discharge pipe 10. The second supply cock 238 is disposed on the supply tube 236. The supply tube 236 is fixed to the discharge pipe 10 at a position where the second supply cock 238 is disposed. The second supply cock 238 is operated by a user's hand. The second supply cock 238 opens and closes the supply tube 236.

[0074] As shown in FIG. 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 tube 66 includes a first tip tube 67 and a second tip tube 68 attached to the front end of the first tip tube 67, and the second supply pipe 240 is formed integrally with the first tip tube 67. The second supply pipe 240 includes an outer portion 244, a first inner portion 246, and a second inner portion 248. The outer portion 244 is disposed outside the tip tube 66. The third supply cock 242 is disposed in the outer portion 244. The third supply cock 242 is operated by the user's hand. The third supply cock 242 opens and closes the outer portion 244. The first inner portion 246 and the second inner portion 248 are disposed inside the tip tube 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 tip tube 68. When the first supply cock 232 (see FIG. 11), the solenoid valve 234 (see FIG. 11), the second supply cock 238 (see FIG. 8), and the third supply cock 242 are open, the liquid in the liquid tank 24 (see FIG. 8) can flow through the first supply pipe 230 (see FIG. 8), the supply tube 236, and the second supply pipe 240.

[0075] In the following, an example will be described in which the longitudinal direction of the tip tube 66 is aligned with the front-rear direction. The work machine 2 further includes a tubular member 250 and a liquid nozzle 252. The tubular member 250 is disposed inside the second tip tube 68. The tubular member 250 has a generally cylindrical shape with its longitudinal direction aligned with the front-rear direction. The tubular member 250 includes a front-side tubular portion 250a and a rear-side tubular portion 250b. The front-side tubular portion 250a is connected to the second tip tube 68 via a plurality of fins 254. The front-side tubular portion 250a, the plurality of fins 254, and the second tip tube 68 are integrally formed. The rear-side tubular portion 250b is disposed rearward of the front-side tubular portion 250a. The rear-side tubular portion 250b is connected to the fins 254 and the second tip tube 68 with screws. The diameter of the inner surface of the tubular member 250 decreases and then increases from the rear end to the front end. A portion of the air flowing inside the tip tube 66 flows inside the tubular member 250 as shown by arrow F1 in Figure 22, and the remainder of the air flowing inside the tip tube 66 flows outside the tubular member 250 as shown by arrow F2 in Figure 22.

[0076] The liquid nozzle 252 is, for example, an ultra-low volume type nozzle. The liquid nozzle 252 is disposed inside the second distal end tube 68. The front end of the liquid nozzle 252 is disposed closest to (the most forward end of) the discharge opening 68a of the second distal end tube 68, and the rear end of the liquid nozzle 252 is disposed farthest from (the most rearward end of) the discharge opening 68a of the second distal end tube 68. The front end of the liquid nozzle 252 corresponds to the front end 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-to-rear direction. The liquid nozzle 252 is made of a metal material, such as brass. In a modified example, the liquid nozzle 252 may be made of a resin material. As shown in FIG. 23 , the liquid nozzle 252 includes an insertion portion 256 and a nozzle portion 258. The insertion portion 256 has a substantially cylindrical shape. As shown in FIG. 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 thread portion 264 is formed on the outer surface of the insertion portion 256. A female thread portion 248a is formed on the inner surface of the second inner portion 248. The insertion portion 256 is connected to the second inner portion 248 by inserting the insertion portion 256 into the inner surface of the second inner portion 248 and threading the male thread portion 264 of the insertion portion 256 into the female thread portion 248a of 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 creates a seal between the outer surface of the insertion portion 256 and the inner surface of the second inner portion 248.

[0077] 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 part of the outer shape of the nozzle portion 258. A portion of the air flowing inside the tip tube 66 (see FIG. 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 has 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 smoothly curved shape. The second side surface 270 is located on the front side 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-to-rear direction. As shown in FIG. 22, at least a portion of the first side surface 268 and the second side surface 270 are surrounded by the rear tubular portion 250b.

[0078] As shown in FIG. 24, the liquid nozzle 252 further includes a liquid passage 274. The liquid passage 274 is disposed inside the insertion portion 256 and the nozzle portion 258. The liquid passage 274 extends from the rear end (base end) to the front end (tip end) of the liquid nozzle 252. The liquid passage 274 is disposed on the central axis CX of the liquid nozzle 252. In FIGS. 24 and 25, the central axis CX is indicated by a dashed line. The central axis CX extends in the front-to-rear direction (the longitudinal direction of the liquid nozzle 252). The liquid passage 274 includes a main passage 276, a transition passage 278, and a throttle 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 portion 256 toward the front side. The main passage 276 is disposed across the insertion portion 256 and the nozzle portion 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 toward the front. The diameter of the throttle passage 280 is smaller than the diameter of the main passage 276. The diameter of the throttle passage 280 is, for example, 0.5 mm. The throttle passage 280 extends from the front end of the transition passage 278 to a tip end surface 282 of the nozzle portion 258.

[0079] The tip surface 282 of the nozzle portion 258 corresponds to the tip surface of the liquid nozzle 252. The tip surface 282 includes an inclined surface 284 and a non-inclined surface 286. The inclined surface 284 is provided with a discharge port 280a of the throttle passage 280. 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 defined as an imaginary plane VP1, the inclined surface 284 is inclined with respect to the imaginary plane VP1. In FIG. 25, the imaginary plane VP1 is illustrated by a dashed line. The inclination angle of the inclined surface 284 with respect to the imaginary plane VP1 is, for example, 5 degrees or more, and in this embodiment, is 20 degrees. The front end of the inclined surface 284 is located forward of the rear end of the inclined surface 284 (toward the tip of the liquid nozzle 252). The front end of the inclined surface 284 is farther from the central axis CX than the rear end of the inclined surface 284. That is, the inclined surface 284 becomes more distant from the central axis CX as it approaches the front side (the tip side of the liquid nozzle 252).

[0080] The non-inclined surface 286 is disposed around the entire periphery of the inclined surface 284. The non-inclined surface 286 is disposed forward of the inclined surface 284. The non-inclined surface 286 is farther from the central axis CX than the inclined surface 284. The non-inclined surface 286 is approximately parallel to the imaginary plane VP1. The non-inclined surface 286 is inclined with respect to the inclined surface 284. In addition, the non-inclined surface 286 is approximately perpendicular to the second side surface 270.

[0081] The liquid nozzle 252 further includes a corner 290. The corner 290 is farther from the central axis CX than the non-inclined surface 286. As shown in FIG. 26, the corner 290 connects the second side surface 270 and the non-inclined surface 286. FIG. 26 is an enlarged cross-sectional view of the corner 290 of the liquid nozzle 252, exaggerating the corner 290. The corner 290 is disposed around the entire periphery of the non-inclined surface 286. The corner 290 forms a corner at 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 angle). The corner 290 may be sharp at an acute angle or an obtuse angle. The corner 290 has a curved shape. In a modified example, the corner 290 may have a flat shape. The corner portion 290 is connected to the second side surface 270 at a side surface connection point 292 and to the non-inclined surface 286 at a tip connection point 294. Near the corner portion 290, an imaginary side surface 296 extending from the second side surface 270 and an imaginary tip surface 298 extending from the non-inclined surface 286 intersect at a substantially right angle at a first point 300. The distance L1 between the first point 300 and the side surface connection point 292 is, for example, 0.3 mm or less. The distance L2 between the first point 300 and the tip connection point 294 is, for example, 0.3 mm or less. The distance L2 is substantially equal to the distance L1. In a modified example, the distance L2 may be different from the distance L1.

[0082] Next, a method for manufacturing the liquid nozzle 252 will be described. The manufacturing method includes an insertion portion cutting step, a tip surface cutting step, a side surface cutting step, and a liquid flow path forming step. As shown in FIG. 24, in the insertion portion cutting step, a cutting blade is moved from the rear end (base end) of the liquid nozzle 252 toward the front end (tip end) to form the insertion portion 256 in 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 in the insertion portion 256. Next, as shown in FIG. 26, in the tip surface cutting step, the cutting blade is moved in a direction away from the central axis CX (in a first direction D1 in FIG. 26) at the front end (tip end) of the liquid nozzle 252, starting from the central axis CX, to form a tip surface 282 in the liquid nozzle 252. Next, in the side surface cutting process, the cutting blade is moved from the insertion portion 256 toward the tip surface 282 (in the second direction D2 in FIG. 26 ) on the side of the liquid nozzle 252 to form a side surface 266 on the liquid nozzle 252. As a result, a sharp corner 290 is formed at the front end (tip) of the liquid nozzle 252. At this time, a minute protrusion (burr) (not shown) is formed at the corner 290, and this protrusion is positioned closer to the central axis CX than the second side surface 270 and extends toward the front. In other words, the protrusion does not protrude in a direction away from the central axis CX than the second side surface 270. Finally, as shown in FIG. 24 , in the liquid flow path forming process, a punch is inserted into the liquid nozzle 252 to form a liquid passage 274 in the liquid nozzle 252.

[0083] Next, the behavior of the liquid discharged from the liquid nozzle 252 when it is atomized will be described. First, as shown in FIG. 22, when the fan 44 (see FIG. 7) is rotated by the rotation of the electric motor 46 (see FIG. 7), air flows into the discharge pipe 10. After flowing through the discharge pipe 10 to the tip pipe 66, the air flows into the interior of the tubular member 250 as indicated by arrow F1 in FIG. 22, and flows along the side surface 266 of the liquid nozzle 252 toward the front end (tip) of the liquid nozzle 252. Furthermore, since the first side surface 268 of the liquid nozzle 252 is surrounded by the tubular member 250 and the diameter of the first side surface 268 decreases from the rear end to the front end of the nozzle portion 258, the air can more easily flow into the interior of the tubular member 250, and the space through which the air flows (the space around the first side surface 268) becomes narrower, thereby increasing the flow rate of the air. The air flowing along the side surface 266 passes through the liquid nozzle 252 and flows inside the tubular member 250 from the rear end toward the front end of the tubular member 250. As shown in FIG. 25 , this air flow generates a pressure difference between the area near the side surface 266 and the front area of ​​the tip surface 282 of the liquid nozzle 252. As a result, an air flow (vortex flow) SW1 shown in FIG. 25 is generated in the front area of ​​the tip surface 282 of the liquid nozzle 252. The air flow SW1 first flows along the central axis CX toward the tip surface 282 of the liquid nozzle 252. Next, the air flow SW1 bends in a direction away from the central axis CX and flows over the tip surface 282, in this order, over the inclined surface 284 and the non-inclined surface 286, toward the corner 290. Finally, the air flow SW1 merges with the air flow flowing along the side surface 266 near the corner 290.

[0084] As air flow SW1 flows over tip surface 282 toward corner 290, the liquid that has been discharged from discharge port 280a of throttle passage 280 to the outside of liquid nozzle 252 flows over tip surface 282, in the order of inclined surface 284 and non-inclined surface 286, toward corner 290. The generation of this air flow SW1 causes the liquid to be discharged from discharge port 280a to the outside of liquid nozzle 252 without using a driving source such as a pump.

[0085] 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 puddle 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. Due to the configuration of the liquid nozzle 252 of this embodiment, the electric motor 46-driven (electric) work machine 2 of this embodiment can atomize the liquid even though the air volume of the fan 44 is lower than in an engine-driven work machine.

[0086] 22, the atomized liquid flows inside the tip tube 66 together with the air flowing inside the tubular member 250 as indicated by arrow F1. Thereafter, the liquid and air flowing inside the tubular member 250 merge with the air flowing outside the tubular member 250 as indicated by arrow F2, and are released (sprayed) from the diffusion cover 70 to the outside of the second tip tube 68.

[0087] (effect) The work machine 2 of this embodiment is a backpack-type work machine that is carried on the user's back. The work machine 2 includes a main body unit 4 that includes a discharge pipe 10 for discharging liquid, a battery pack BP (an example of a battery), and a main body housing 16 that supports the battery pack BP, and an elastically deformable frame unit 6 that supports the main body housing 16. The main body unit 4 includes an opposing surface 4a that faces the user's back when the work machine 2 is carried on the user's back. The frame unit 6 includes a pair of side frames 170, 172. When the work machine 2 is placed on a mounting surface P, the direction perpendicular to the mounting surface P is defined as the up-down direction, the direction perpendicular to the opposing surface 4a is defined as the front-rear direction, and the direction perpendicular to the up-down direction and the front-rear direction is defined as the left-right direction. The pair of side frames 170, 172 are positioned outboard of the main body housing 16 in the left-right direction.

[0088] According to the above configuration, when the work implement 2 falls and hits the mounting surface P from the left or right end side of the main unit 4, the side frames 170, 172 elastically deform before the main housing 16 hits the mounting surface P. Therefore, the impact caused by the fall is absorbed by the side frames 170, 172. This makes it possible to prevent the main housing 16 from being damaged.

[0089] The frame unit 6 also includes a rear frame 174 that is disposed rearward of the main body housing 16 in the front-rear direction.

[0090] According to the above configuration, when the work implement 2 falls and collides with the mounting surface P from the rear end side of the main unit 4, the rear frame 174 elastically deforms before the main body housing 16 collides with the mounting surface P. Therefore, the impact caused by the fall is absorbed by the rear frame 174. This makes it possible to prevent the main body housing 16 from being damaged.

[0091] The frame unit 6 also includes a lower frame 178 that is disposed below the main body housing 16 .

[0092] According to the above configuration, when the work implement 2 falls and collides with the mounting surface P from the lower end side of the main unit 4, the lower frame 178 elastically deforms before the main body housing 16 collides with the mounting surface P. Therefore, the impact caused by the fall is absorbed by the lower frame 178. This makes it possible to prevent the main body housing 16 from being damaged.

[0093] The main body housing 16 also has a lower opposing surface 200 that faces the lower frame 178. The lower opposing surface 200 has a curved shape that is convex toward the lower frame 178.

[0094] According to the above configuration, when the work machine 2 collides with the placement surface P and the lower frame 178 elastically deforms, the lower frame 178 comes into contact with the lower opposing surface 200 of the main body housing 16. Thereafter, the lower frame 178 elastically deforms to match the shape of the lower opposing surface 200. This makes it possible to absorb the impact caused by the fall.

[0095] The pair of side frames 170, 172 are disposed outside the battery pack BP.

[0096] According to the above configuration, when the work machine 2 falls and hits the mounting surface P, the side frames 170, 172 elastically deform before the main body housing 16 hits the mounting surface P. Therefore, the impact caused by the fall is absorbed by the side frames 170, 172. This makes it possible to protect the battery pack BP.

[0097] The main unit 4 further includes a liquid tank 24 for storing the liquid discharged from the discharge pipe 10.

[0098] According to the above configuration, when liquid is stored in the liquid tank 24, the work machine 2 becomes heavy. Even when a heavy work machine 2 falls and hits the support surface P from the left or right end of the main unit 4, the side frames 170, 172 elastically deform before the main body housing 16 hits the support surface P. Therefore, the impact of the fall is absorbed by the side frames 170, 172. This makes it possible to prevent damage to the main body housing 16 even with a heavy work machine 2.

[0099] Furthermore, at least a portion of the liquid tank 24 is disposed above the main body housing 16. The liquid tank 24 is provided with a receiving groove 196 that receives the frame unit 6. The frame unit 6 is received in the receiving groove 196 and supports the liquid tank 24 from below.

[0100] According to the above configuration, the frame unit 6 supports the liquid tank 24 from below, so when the work machine 2 falls and hits the mounting surface P, the frame unit 6 can absorb part of the external force acting from the liquid tank 24 on the main body housing 16. This makes it possible to prevent the main body housing 16 from being damaged.

[0101] (Variation) The work machine 2 according to one embodiment may be an engine-powered work machine.

[0102] The work machine 2 according to one embodiment is not limited to a mist blower, and may be, for example, a sprayer or a high-pressure washer.

[0103] The work machine 2 according to one embodiment may be a work machine equipped with a built-in battery. In this case, the built-in battery is charged by connecting a power cord to an external power source.

[0104] The battery unit 22 according to one embodiment may include only one battery pack BP.

[0105] The work machine 2 according to one embodiment is not limited to a backpack-type work machine, but may be, for example, a tabletop-type work machine or a handheld-type work machine.

[0106] The one-way valve 144 according to one embodiment is not limited to an umbrella valve, but may be, for example, a duckbill valve.

[0107] The liquid tank 24 according to one embodiment may not include the filter unit 94 .

[0108] In one embodiment of the liquid tank 24, the side wall 114 may not have the second side portion 122. In this case, the multiple communication holes 126 may be arranged in the first side portion 120 at a location where the engaged rail 124 is partially discontinued.

[0109] 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.

[0110] 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 arranged above the battery unit 22, and the liquid tank 24 may be arranged above the fan unit 18.

[0111] 27, in a liquid nozzle 252 according to one embodiment, a plurality of discharge ports 280a may be formed in a tip surface 282. The plurality of discharge ports 280a may be arranged, for example, around a central axis CX.

[0112] 28, in a liquid nozzle 252 according to one embodiment, the tip surface 282 may further include a central non-inclined surface 310. The central non-inclined surface 310 is substantially parallel to the imaginary plane VP1. The discharge port 280a of the throttle passage 280 is arranged in the central non-inclined surface 310. The inclined surface 284 is connected to the periphery of the central non-inclined surface 310.

[0113] In one embodiment of the liquid nozzle 252, the tip surface 282 may not include the non-inclined surface 286. In this case, the inclined surface 284 is connected to the corner portion 290.

[0114] In the liquid nozzle 252 according to one embodiment, the corner 290 may be disposed on only a portion of the periphery of the tip surface 282 in the circumferential direction. [Explanation of symbols]

[0115] 2: Work equipment 4: Main unit 4a, 30, 90a: opposing surfaces 6: Frame unit 10: Release tube 16: Main body housing 18: Fan unit 20: Control unit 22: Battery unit 24: Liquid tank 44: Fan 46: Electric motor 66: Tip tube 84: Right battery mounting area 86: Left 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: Engagement rail 142:Communication space 144: One-way valve 148: Valve section 170: Right side frame 172: Left side frame 174: Rear frame 178: Lower Frame 196: Receiving groove 200: Lower facing surface 208: Shoulder harness unit 210: Right shoulder harness 212: Left shoulder harness 214: First upper mounting part 218: Second upper mounting part 250: Cylindrical member 252: Liquid nozzle 258: Nozzle part 266: Side 268 :1st side 270:Second side 274:Liquid passage 280a: Outlet 282:Tip surface 284: Inclined surface 290: Corner 296: Virtual side 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: Placement surface SW1: Air flow VP1: Virtual surface

Claims

1. A backpack-type work machine, a discharge pipe for discharging the liquid; a main unit including a battery and a main body housing supporting the battery; a frame unit that supports the main body housing and is elastically deformable, the main unit has a facing surface that faces the back of a user when the backpack-type working machine is carried on the user's back, The frame unit includes a pair of side frames, When the backpack-type working machine is placed on a placement surface, if the direction perpendicular to the placement surface is defined as the up-down direction, the direction perpendicular to the opposing surface is defined as the front-to-rear direction, and the direction perpendicular to the up-down direction and the front-to-rear direction is defined as the left-to-right direction, the pair of side frames are positioned further outward than the main body housing in the left-to-right direction.

2. The backpack-type working machine according to claim 1 , wherein the frame unit includes a rear frame disposed rearward of the main body housing in the front-rear direction.

3. 2. The backpack-type working machine according to claim 1, wherein the frame unit includes a lower frame disposed below the main body housing.

4. the main body housing has a lower opposing surface that faces the lower frame, The backpack-type working machine according to claim 3 , wherein the lower opposing surface has a curved shape that is convex toward the lower frame.

5. The backpack-type working machine according to claim 1 , wherein the pair of side frames are disposed outward of the battery.

6. The backpack-type work machine according to claim 1 , wherein the main unit further comprises a liquid tank that stores the liquid discharged from the discharge pipe.

7. At least a portion of the liquid tank is disposed above the main body housing, the liquid tank has a receiving groove that receives the frame unit, 7. The backpack-type work machine according to claim 6, wherein the frame unit is received in the receiving groove and supports the liquid tank from below.

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