Work machinery

Abstract

To adequately dispose an oil passage for feeding hydraulic oil to an attachment.SOLUTION: A second boom 12 is connected to a tip of a first boom so as to be rotatable in longitudinal direction with respect to the first boom. A third bracket 13 is connected to a tip of the second boom 12 so as to be rotatable in longitudinal direction with respect to the second boom 12. A first attachment oil passage 100 feeds hydraulic oil to an attachment that can be connected to a tip of an arm. An outer surface of the second boom 12 has a top face 12U facing upward and a left side face 12L facing leftward. The first attachment oil passage 100 is disposed so as to extend downward along the top face 12U to the left side face 12L of the second boom 12 and extend upward beyond the top face 12U from the left side face 12L.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to work machines. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2005-61041 (Patent Document 1) discloses that in a hydraulic excavator equipped with a work implement that performs offset operation, a hydraulic hose for an attachment is arranged from a lower boom member to an upper boom member, a cylinder support member, and along one side of the stick as attachment piping for supplying hydraulic oil to an attachment attached to the tip of the stick, and a regular tube is arranged from the tip of the hydraulic hose for the attachment over the back surface of the stick to the other side of the stick. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-61041 Summary of the Invention [Problem to be solved by the invention]

[0004] In a work machine in which a hydraulically driven attachment can be connected to the tip of the work machine, it is required that an oil passage for supplying hydraulic oil to the attachment be appropriately arranged up to the tip of the work machine.

[0005] The present disclosure proposes a work machine in which oil passages for supplying hydraulic oil to an attachment can be appropriately arranged. [Means for solving the problem]

[0006] According to the present disclosure, there is proposed a work machine including a vehicle body, a first boom connected to the vehicle body so as to be rotatable in the vertical direction, a second boom connected to the tip of the first boom so as to be rotatable in the left-right direction relative to the first boom, a bracket connected to the tip of the second boom so as to be rotatable in the left-right direction relative to the second boom, an arm connected to the bracket so as to be rotatable in the vertical direction, and an attachment oil passage that supplies hydraulic oil to an attachment connectable to the tip of the arm. The outer surface of the second boom has an upper surface facing upward and a side surface facing laterally. The attachment oil passage is arranged to extend downward from the upper surface along the side surface and further extend upward from the side surface beyond the upper surface. [Effects of the Invention]

[0007] According to the work machine of the present disclosure, the oil passage for supplying hydraulic oil to the attachment can be appropriately arranged. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a side view of a hydraulic excavator. [Figure 2] FIG. 10 is a perspective view showing the arrangement of attachment oil passages for the second boom. [Figure 3] FIG. 10 is a perspective view seen from a different angle showing the arrangement of attachment oil passages for the second boom. [Figure 4] FIG. 10 is a side view of the second boom when the second boom is offset to the right. [Figure 5] FIG. 10 is a side view of the second boom when the second boom is offset to the left. [Figure 6] FIG. 10 is a side view showing the arrangement of the arm cylinder relative to the second boom when the arm is dumped. [Figure 7] FIG. 2 is a side view showing an attachment attached to the tip of the arm. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. The names and functions of the components are also the same. Therefore, detailed description thereof will not be repeated.

[0010] 1 is an external view of a hydraulic excavator 1 as an example of a work machine based on an embodiment. In the embodiment, an offset hydraulic excavator 1 will be described as an example of the work machine.

[0011] As shown in FIG. 1, the hydraulic excavator 1 mainly comprises a work implement 10, a revolving unit 30, and a running unit 40. The work implement 10 is hydraulically operated. The revolving unit 30 and the running unit 40 form the vehicle body of the hydraulic excavator 1. The running unit 40 has a pair of left and right tracks 42 and a pair of travel motors 44. The travel motors 44 are provided as a drive source for the running unit 40. The travel motors 44 are hydraulic motors that are hydraulically operated.

[0012] When the hydraulic excavator 1 is in operation, the running body 40, more specifically the crawler belt 42, is in contact with the ground. The running body 40 can travel on the ground by the rotation of the crawler belt 42. Note that the running body 40 may have wheels (tires) instead of the crawler belt 42.

[0013] The running body 40 has a blade 50. The blade 50 is installed in front of the crawler belt 42 and extends in the vehicle width direction of the hydraulic excavator 1. The blade 50 is attached to a frame that supports the crawler belt 42. Using the blade 50, the hydraulic excavator 1 is capable of performing earth removal work, ground leveling work, and the like.

[0014] The rotating body 30 is disposed on the running body 40 and is supported by the running body 40. The rotating body 30 is movable relative to the running body 40. The rotating body 30 has a rotating frame 31.

[0015] The swivel frame 31 is attached to the traveling body 40 via a swivel circle portion. The swivel circle portion is located approximately in the center of the body of the hydraulic excavator 1 in a plan view. The swivel circle portion has a roughly annular shape and has internal teeth for swivel on its inner circumferential surface. A pinion that meshes with these internal teeth is attached to a swivel motor (not shown). The swivel motor may be a hydraulic motor or an electric motor.

[0016] The swivel frame 31 is mounted on the running body 40 so as to be rotatable relative to the running body 40 around a rotation axis at the center of the swivel circle portion. The driving force transmitted from the swivel motor rotates the swivel circle portion, thereby allowing the swivel frame 31 to rotate relative to the running body 40.

[0017] The rotating body 30 has a cab 32. The cab 32 is mounted on the rotating frame 31. The crew (operator) of the hydraulic excavator 1 sits in this cab 32 to operate the hydraulic excavator 1. The cab 32 is disposed on the left side of the work implement 10. The cab 32 and the work implement 10 are disposed side by side on the left and right.

[0018] The cab 32 is provided with a driver's seat where an operator sits. The operator can operate the hydraulic excavator 1 from within the cab 32. From within the cab 32, the operator can operate the work implement 10, can operate the rotating unit 30 relative to the traveling unit 40, and can operate the traveling of the hydraulic excavator 1 using the traveling unit 40. In the present disclosure, the hydraulic excavator 1 is operated from within the cab 32, but it may also be remotely controlled by wireless from a location away from the hydraulic excavator 1.

[0019] In the embodiment, the positional relationship of each part in the hydraulic excavator 1 will be described with reference to an operator seated in the driver's seat inside the cab 32. The front-to-rear direction refers to the front-to-rear direction of the operator seated in the driver's seat. The direction facing the operator seated in the driver's seat is the forward direction, and the direction behind the operator seated in the driver's seat is the rearward direction. The left-to-right direction refers to the left-to-right direction of the operator seated in the driver's seat. The right and left sides of the operator seated in the driver's seat when facing directly ahead are the right and left directions, respectively. The up-to-down direction refers to the up-to-down direction of the operator seated in the driver's seat. The side near the feet of the operator seated in the driver's seat is the down side, and the side above the head is the up side.

[0020] In the front-to-rear direction, the side where the work implement 10 protrudes from the revolving body 30 is the front direction, and the opposite direction to the front direction is the rear direction. Looking forward, the right and left sides in the left-right direction are the right direction and the left direction, respectively. In the up-down direction, the side with the ground is the bottom side, and the side with the sky is the top side.

[0021] The rotating body 30 has an engine room 34 that houses an engine, and a counterweight provided at the rear of the rotating body 30. The engine room 34 contains an engine that generates driving force, a hydraulic pump that receives the driving force generated by the engine and supplies hydraulic oil to the hydraulic actuator, and other components. The engine, hydraulic pump, and other components are mounted on the rotating frame 31.

[0022] The work implement 10 is mounted on and supported by a rotating body 30. The work implement 10 has a first boom 11, a second boom 12, a third bracket (corresponding to an example of a "bracket") 13, an arm 14, and a bucket 15. The bucket 15 may have multiple blades at its tip, or the tip may be formed from a straight steel plate.

[0023] The work implement 10 has a boom cylinder 21, an offset cylinder 22, an arm cylinder 23, and an attachment cylinder 24. The boom cylinder 21, the offset cylinder 22, the arm cylinder 23, and the attachment cylinder 24 are each a hydraulic cylinder driven by hydraulic oil. The hydraulic oil is supplied to the hydraulic cylinders from a hydraulic pump housed in an engine room 34 and driven by the engine.

[0024] The base end of the first boom 11 is connected to the revolving unit 30 via a boom foot pin (not shown) so as to be rotatable in the vertical direction. A boom cylinder 21 connects the tip end of the first boom 11 to the revolving unit 30 below the first boom 11. The boom cylinder 21 operates the first boom 11. As the boom cylinder 21 extends and retracts, the first boom 11 rotates in the vertical direction relative to the revolving unit 30 around the boom foot pin.

[0025] The base end of the second boom 12 is connected to the tip of the first boom 11 via a first offset pin 19. The second boom 12 is rotatable in the left-right direction relative to the first boom 11 around the first offset pin 19. The third bracket 13 is connected to the tip of the second boom 12 via a second offset pin 20. The third bracket 13 is rotatable in the left-right direction relative to the second boom 12 around the second offset pin 20.

[0026] The tip end of the first boom 11 and the third bracket 13 are connected by a link rod 25. The link rod 25 and the offset cylinder 22 are disposed on the left side of the second boom 12. The offset cylinder 22 connects the base end of the second boom 12 and the third bracket 13. The extension and contraction of the offset cylinder 22 causes the third bracket 13 to move (offset) left and right relative to the first boom 11.

[0027] By retracting the offset cylinder 22, the second boom 12 operates to tilt to the right relative to the first boom 11, thereby offsetting the positions of the arm 14 and the bucket 15 to the right. By extending the offset cylinder 22, the second boom 12 operates to tilt to the left relative to the first boom 11, thereby offsetting the positions of the arm 14 and the bucket 15 to the left. By extending and contracting the offset cylinder 22, the second boom 12 rotates relative to the first boom 11 about the first offset pin 19, and operates in the left-right direction.

[0028] The base end of the arm 14 is connected to the third bracket 13 via an arm connecting pin 17 so as to be rotatable in the vertical direction. The arm cylinder 23 has a cylinder tube connected to the third bracket 13 via a cylinder connecting pin 27, and a rod whose tip is connected to the arm 14. The arm cylinder 23 operates the arm. As the arm cylinder 23 extends and retracts, the arm 14 rotates vertically relative to the third bracket 13 around the arm connecting pin 17.

[0029] The bucket 15 is connected to the tip of the arm 14 via an attachment connecting pin 18. An attachment cylinder 24 connects the base end of the arm 14 to the bucket 15. The attachment cylinder 24 operates the bucket 15. As the attachment cylinder 24 extends and retracts, the bucket 15 rotates relative to the arm 14 around the attachment connecting pin 18.

[0030] An arm operating oil passage 300 is connected to the arm cylinder 23. The arm operating oil passage 300 is a path for hydraulic oil that extends from a hydraulic pump (not shown) in the engine room 34 to the arm cylinder 23. The hydraulic oil for operating the arm 14 flows via the arm operating oil passage 300 and is supplied to the arm cylinder 23.

[0031] A cylinder oil passage 320 is connected to the attachment cylinder 24. The cylinder oil passage 320 is a path for hydraulic oil that extends from a hydraulic pump (not shown) in the engine compartment 34 to the attachment cylinder 24. The hydraulic oil for operating the bucket 15 flows through the cylinder oil passage 320 and is supplied to the attachment cylinder 24.

[0032] The second boom 12 has a hollow cylindrical shape with a space formed inside. The cylinder oil passage 320 is arranged in the space inside the second boom 12. Because the cylinder oil passage 320 is built into the second boom 12, it is possible to prevent obstacles from coming into contact with the cylinder oil passage 320.

[0033] In the hydraulic excavator 1 of the embodiment, depending on the type of work, other types of attachments such as a breaker, crusher, grapple, etc. can be connected to the tip of the arm 14 instead of the excavation bucket 15. Fig. 7 is a side view showing an attachment attached to the tip of the arm 14. In the example shown in Fig. 7, a breaker 15A as an example of an attachment is connected to the tip of the arm 14 instead of the bucket 15 shown in Fig. 1.

[0034] The breaker 15A is connected to the tip of the arm 14 via the attachment connecting pin 18. Hydraulic oil supplied to the attachment cylinder 24 via the cylinder oil passage 320 is used to extend and retract the attachment cylinder 24. As the attachment cylinder 24 extends and retracts, the breaker 15A rotates relative to the arm 14 around the attachment connecting pin 18 as the center of rotation, changing the attitude of the breaker 15A relative to the arm 14.

[0035] The hydraulic excavator 1 is equipped with a first attachment oil passage 100 and a second attachment oil passage 200 for supplying hydraulic oil to the attachment. Either the first attachment oil passage 100 or the second attachment oil passage 200 is a flow path for hydraulic oil flowing from the hydraulic pump toward the attachment, and the other is a flow path for hydraulic oil returning from the attachment to the hydraulic pump. In the case where the attachment is a breaker 15A shown in Fig. 7, the hydraulic oil supplied to the breaker 15A via the first attachment oil passage 100 and the second attachment oil passage 200 is used to vibrate the breaker 15A.

[0036] 2 and 3 are perspective views showing the arrangement of the first attachment oil passage 100 and the second attachment oil passage 200 relative to the second boom 12. Figures 2 and 3 show the periphery of the connection between the second boom 12 and the third bracket 13, viewed from different angles.

[0037] The second boom 12 has a generally rectangular cylindrical shape. The outer surface of the second boom 12 has an upper surface 12U facing upward, a lower surface 12B (FIG. 6) facing downward, a left side surface 12L facing leftward, and a right side surface 12R facing rightward.

[0038] The lower surface 12B is the surface of the outer surface of the second boom 12 that faces the ground and that comes into contact with the crawler belt 42. The upper surface 12U is the surface of the outer surface of the second boom 12 that faces upward. The upper surface 12U and the lower surface 12B are outer surfaces of the second boom 12 that are opposite each other. The upper surface 12U is the surface that faces the arm cylinder 23. In a state in which the second boom 12 as a whole extends parallel to the ground as shown in FIG. 1, the lower surface 12B faces downward and the upper surface 12U faces upward.

[0039] As the first boom 11 rotates relative to the revolving unit 30, the second boom 12 also rotates in the vertical direction relative to the revolving unit 30. The upper surface 12U and the lower surface 12B may be positioned so as to be inclined relative to the vertical direction depending on the change in the attitude of the work implement 10.

[0040] The left side surface 12L and the right side surface 12R are outer surfaces of the second boom 12 that are opposite to each other. The left side surface 12L and the right side surface 12R have upper edges that are connected to the upper surface 12U and lower edges that are connected to the lower surface 12B. The upper surface 12U and the lower surface 12B have left edges that are connected to the left side surface 12L and right edges that are connected to the right side surface 12R.

[0041] The second boom 12 rotates left and right relative to the first boom 11 around a first offset pin 19. The left side surface 12L and the right side surface 12R may be positioned so as to be inclined left and right depending on the posture of the work implement 10.

[0042] The first attachment oil passage 100 includes a first pipe section 110, a second hose section 120, a third pipe section 130, a fourth hose section 140, a fifth pipe section 150, a sixth hose section 160, and a seventh pipe section 170. The first pipe section 110, the third pipe section 130, the fifth pipe section 150, and the seventh pipe section 170 are formed of a relatively hard material, such as a metal material, typically a steel pipe for pressure piping. The second hose section 120, the fourth hose section 140, and the sixth hose section 160 are formed of a relatively soft material, such as rubber or resin.

[0043] The first pipe section 110, the third pipe section 130, the fifth pipe section 150, and the seventh pipe section 170 have rigidity. The first pipe section 110, the third pipe section 130, the fifth pipe section 150, and the seventh pipe section 170 are arranged along any of the link members that make up the work implement 10. The first pipe section 110, the third pipe section 130, the fifth pipe section 150, and the seventh pipe section 170 are provided in locations of the first attachment oil passage 100 where deformation is small even when the work implement 10 is in operation.

[0044] The second hose section 120, the fourth hose section 140, and the sixth hose section 160 are flexible. The second hose section 120, the fourth hose section 140, and the sixth hose section 160 are arranged at joints that connect link members that make up the work machine 10. The second hose section 120, the fourth hose section 140, and the sixth hose section 160 are provided in portions of the first attachment oil passage 100 that are subject to large deformation when the work machine 10 is in operation.

[0045] Specifically, the first pipe section 110 is disposed so as to extend along the outer surface of the first boom 11. The first pipe section 110 is disposed along the upper surface of the first boom 11.

[0046] The proximal end of the second hose section 120 is connected to the distal end of the first pipe section 110. In the direction extending along the work implement 10, the second hose section 120 is disposed farther from the revolving unit 30 than the first pipe section 110. In the description herein, the base end side in the direction extending along the work implement 10 (the side where the first boom 11 is connected to the revolving unit 30) is referred to as the "proximal" side, and the tip end side in the direction extending along the work implement 10 (the side where the bucket 15 or an attachment is disposed) is referred to as the "distal" side. The proximal end of the arm 14 is the base end of the arm 14 where the arm 14 is connected to the third bracket 13 via an arm connecting pin 17. The distal end of the arm 14 is the tip end of the arm 14 where an attachment (such as the bucket 15 or breaker 15A) is connected to the arm 14 via an attachment connecting pin 18. Depending on the attitude of the work implement 10 , the distance between the boom foot pin and the distal end of the arm 14 may be smaller than the distance between the boom foot pin and the proximal end of the arm 14 .

[0047] The second hose section 120 is disposed across the first boom 11 and the second boom 12. The second hose section 120 extends from the tip of the first boom 11 toward the second boom 12, straddling a first offset pin 19 that connects the first boom 11 and the second boom 12. The second hose section 120 is disposed so as to extend along the upper surface of the first boom 11, go over the first offset pin 19, and extend along the upper surface 12U of the second boom 12.

[0048] A proximal end of the third pipe section 130 is connected to the distal end of the second hose section 120. In the direction extending along the work implement 10, the third pipe section 130 is disposed farther from the rotating bed 30 than the second hose section 120. The third pipe section 130 is disposed along the upper surface 12U of the second boom 12, turns left, and extends along the left side surface 12L of the second boom 12. The third pipe section 130 extends downward from the upper surface 12U of the second boom 12 along the left side surface 12L. The third pipe section 130 extends along the outer surface of the second boom 12 from the upper surface 12U to the left side surface 12L of the second boom 12.

[0049] A proximal end of a fourth hose section 140 is connected to a distal end of the third pipe section 130. In the direction extending along the work implement 10, the fourth hose section 140 is disposed farther from the revolving bed 30 than the third pipe section 130. The fourth hose section 140 is disposed from the second boom 12 to the third bracket 13. The fourth hose section 140 extends from the tip of the second boom 12 toward the third bracket 13, straddling a second offset pin 20 that connects the second boom 12 and the third bracket 13. The fourth hose section 140 extends upward from the left side surface 12L of the second boom 12, past the top surface 12U. The fourth hose section 140 is disposed so as to extend upward along the left side surface 12L of the second boom 12, turn right, extend in the longitudinal direction of the second boom 12, past the second offset pin 20, and extend inside the third bracket 13.

[0050] 1 and 6 described below, a part of the fourth hose section 140 that is above the upper surface 12U of the second boom 12 has a part that is positioned farther away from the upper surface 12U of the second boom 12 than a part of the third pipe section 130 that is above the upper surface 12U of the second boom 12. In a direction perpendicular to the upper surface 12U of the second boom 12, the maximum distance between the part of the fourth hose section 140 that is above the upper surface 12U and the upper surface 12U is greater than the maximum distance between the part of the third pipe section 130 that is above the upper surface 12U and the upper surface 12U.

[0051] The proximal end of the fifth pipe section 150 is connected to the distal end of the fourth hose section 140. In the direction extending along the work implement 10, the fifth pipe section 150 is disposed farther from the rotating body 30 than the fourth hose section 140. The fifth pipe section 150 is disposed above the third bracket 13 so as to extend in the left-right direction.

[0052] A proximal end of a sixth hose section 160 is connected to a distal end of the fifth pipe section 150. In the direction extending along the work implement 10, the sixth hose section 160 is disposed farther from the rotating body 30 than the fifth pipe section 150. The sixth hose section 160 is disposed from the third bracket 13 to the arm 14. The sixth hose section 160 extends from the third bracket 13 toward the arm 14, straddling an arm connecting pin 17 that connects the third bracket 13 and the arm 14. The sixth hose section 160 is disposed so as to extend along the left side surface of the third bracket 13, beyond the arm connecting pin 17, and along the left side surface of the arm 14.

[0053] The proximal end of the seventh pipe section 170 is connected to the distal end of the sixth hose section 160. In the direction extending along the work implement 10, the seventh pipe section 170 is disposed farther from the rotating body 30 than the sixth hose section 160. The sixth hose section 160 is gently curved as a whole from the proximal end connected to the fifth pipe section 150 to the distal end connected to the seventh pipe section 170. The seventh pipe section 170 is disposed along the left side surface of the arm 14.

[0054] The first attachment oil passage 100 further has an eighth hose section 180 shown in Fig. 7. The eighth hose section 180 has a proximal end connected to the distal end of the seventh pipe section 170 and a distal end connected to the breaker 15A (an example of an attachment shown in Fig. 7). The eighth hose section 180 extends from the arm 14 to the breaker 15A side, straddling the attachment connecting pin 18 which is the connecting section between the arm 14 and the breaker 15A.

[0055] The second attachment oil passage 200 has a first pipe section 210, a second hose section 220, a third pipe section 230, a fourth hose section 240, a fifth pipe section 250, a sixth hose section 260, and a seventh pipe section 270. The first pipe section 210, the third pipe section 230, the fifth pipe section 250, and the seventh pipe section 270 are made of, for example, a metal material, typically a steel pipe for pressure piping. The second hose section 220, the fourth hose section 240, and the sixth hose section 260 are made of, for example, rubber or resin.

[0056] The first pipe section 210, the third pipe section 230, the fifth pipe section 250, and the seventh pipe section 270 have rigidity. The first pipe section 210, the third pipe section 230, the fifth pipe section 250, and the seventh pipe section 270 are arranged along any of the link members that make up the work implement 10. The first pipe section 210, the third pipe section 230, the fifth pipe section 250, and the seventh pipe section 270 are provided in locations of the second attachment oil passage 200 that experience little deformation even when the work implement 10 is in operation.

[0057] The second hose section 220, the fourth hose section 240, and the sixth hose section 260 are flexible. The second hose section 220, the fourth hose section 240, and the sixth hose section 260 are arranged at the positions of the joints that connect the link members that make up the work machine 10. The second hose section 220, the fourth hose section 240, and the sixth hose section 260 are provided in the second attachment oil passage 200 at locations that are subject to large deformation when the work machine 10 is in operation.

[0058] Specifically, the first pipe section 210 is disposed so as to extend along the outer surface of the first boom 11. The first pipe section 210 is disposed along the upper surface of the first boom 11.

[0059] A proximal end of the second hose section 220 is connected to the distal end of the first pipe section 210. In the direction extending along the work implement 10, the second hose section 220 is disposed farther from the revolving unit 30 than the first pipe section 210. The second hose section 220 is disposed from the first boom 11 to the second boom 12. The second hose section 220 extends from the tip of the first boom 11 toward the second boom 12, straddling a first offset pin 19 that connects the first boom 11 and the second boom 12. The second hose section 220 is disposed so as to extend along the upper surface of the first boom 11, pass over the first offset pin 19, and extend along the upper surface 12U of the second boom 12.

[0060] A proximal end of the third pipe section 230 is connected to the distal end of the second hose section 220. In the direction extending along the work implement 10, the third pipe section 230 is disposed farther from the rotating bed 30 than the second hose section 220. The third pipe section 230 is disposed along the upper surface 12U of the second boom 12, turns to the right, and extends along the right side surface 12R of the second boom 12. The third pipe section 230 extends downward from the upper surface 12U of the second boom 12 along the right side surface 12R. The third pipe section 130 extends along the outer surface of the second boom 12 from the upper surface 12U to the right side surface 12R of the second boom 12.

[0061] A proximal end of a fourth hose section 240 is connected to a distal end of the third pipe section 230. In the direction extending along the work implement 10, the fourth hose section 240 is disposed farther from the revolving bed 30 than the third pipe section 230. The fourth hose section 240 is disposed from the second boom 12 to the third bracket 13. The fourth hose section 240 extends from the tip of the second boom 12 toward the third bracket 13, straddling a second offset pin 20 that connects the second boom 12 and the third bracket 13. The fourth hose section 240 extends upward from the right side surface 12R of the second boom 12, past the upper surface 12U. The fourth hose section 240 is disposed so as to extend upward along the right side surface 12R of the second boom 12, turn left, extend in the longitudinal direction of the second boom 12, past the second offset pin 20, and extend inside the third bracket 13.

[0062] 1 and 6 described below, a part of the fourth hose section 240 that is above the upper surface 12U of the second boom 12 has a part that is positioned farther away from the upper surface 12U of the second boom 12 than a part of the third pipe section 230 that is above the upper surface 12U of the second boom 12. In a direction perpendicular to the upper surface 12U of the second boom 12, the maximum distance between the part of the fourth hose section 240 that is above the upper surface 12U and the upper surface 12U is greater than the maximum distance between the part of the third pipe section 230 that is above the upper surface 12U and the upper surface 12U.

[0063] The proximal end of the fifth pipe section 250 is connected to the distal end of the fourth hose section 240. In the direction extending along the work implement 10, the fifth pipe section 250 is disposed farther from the rotating body 30 than the fourth hose section 240. The fifth pipe section 250 is disposed above the third bracket 13 so as to extend in the left-right direction.

[0064] A proximal end of a sixth hose section 260 is connected to a distal end of the fifth pipe section 250. In the direction extending along the work implement 10, the sixth hose section 260 is disposed farther from the rotating body 30 than the fifth pipe section 250. The sixth hose section 260 is disposed from the third bracket 13 to the arm 14. The sixth hose section 260 extends from the third bracket 13 toward the arm 14, straddling the arm connecting pin 17 which is a connecting section between the third bracket 13 and the arm 14. The sixth hose section 260 is disposed so as to extend along the right side surface of the third bracket 13, beyond the arm connecting pin 17, and along the right side surface of the arm 14.

[0065] The proximal end of the seventh pipe section 270 is connected to the distal end of the sixth hose section 260. In the direction extending along the work implement 10, the seventh pipe section 270 is disposed farther from the rotating bed 30 than the sixth hose section 260. The sixth hose section 260 is curved in a gentle arc overall from the proximal end connected to the fifth pipe section 250 to the distal end connected to the seventh pipe section 270. The seventh pipe section 270 is disposed along the right side surface of the arm 14.

[0066] Although not shown, the second attachment oil passage 200 further has an eighth hose section similar to the eighth hose section 180 of the first attachment oil passage 100. The eighth hose section has a proximal end connected to the distal end of the seventh pipe section 270 and a distal end connected to the breaker 15A (an example of an attachment shown in FIG. 7). The eighth hose section extends from the arm 14 toward the breaker 15A, straddling the attachment connecting pin 18, which is the connecting section between the arm 14 and the breaker 15A.

[0067] The first attachment oil passage 100 and the second attachment oil passage 200 form a three-dimensional route around the second boom 12. The proximal ends of the third pipe sections 130, 230, which are connected to the second hose sections 120, 220, are located opposite the upper surface 12U of the second boom 12. The distal ends of the third pipe sections 130, 230, which are connected to the fourth hose sections 140, 240, are located opposite the left side surface 12L and the right side surface 12R of the second boom 12, respectively. The third pipe sections 130 and 230 are arranged in a bifurcated manner. The first attachment oil passage 100 is bent at the connection portion between the third pipe section 130 and the fourth hose section 140. The second attachment oil passage 200 is bent at the connection portion between the third pipe section 230 and the fourth hose section 240.

[0068] The first attachment oil passage 100 and the second attachment oil passage 200 are arranged to extend over the entire second boom 12 in the longitudinal direction of the second boom 12. In the longitudinal direction of the second boom 12, the first attachment oil passage 100 and the second attachment oil passage 200 do not face the upper surface 12U of the second boom 12, and there are portions where the upper surface 12U is exposed.

[0069] As described above, each hose section is made of a soft material. To protect the hose material, a protective material may be provided to cover the outer periphery of each hose section. This protective material may be, for example, a metal wire or a relatively hard resin material.

[0070] Fig. 4 is a view of the second boom 12 as seen from the left side when the second boom 12 is offset to the right. Fig. 5 is a view of the second boom 12 as seen from the left side when the second boom 12 is offset to the left.

[0071] 4 and 5, the offset cylinder 22 has a cylinder tube 22A and a rod 22B. The cylinder tube 22A has a hollow cylindrical shape and houses a piston therein. The rod 22B is supported by the cylinder tube 22A. The rod 22B has a first end connected to the piston inside the cylinder tube 22A and a second end disposed outside the cylinder tube 22A and connected to the third bracket 13. The rod 22B is disposed to penetrate an end face of the cylinder tube 22A and is reciprocable relative to the cylinder tube 22A in the longitudinal direction of the cylinder tube 22A.

[0072] The rod 22B is configured so that the length that protrudes from the end of the cylinder tube 22A to the outside of the cylinder tube 22A can be changed. The offset cylinder 22 is configured so that its overall length can be extended or retracted in accordance with the reciprocating movement of the rod 22B.

[0073] As the length that rod 22B protrudes from cylinder tube 22A decreases, offset cylinder 22 contracts, second boom 12 tilts to the right relative to first boom 11, and arm 14 and bucket 15 are offset to the right relative to first boom 11. The arrangement of work implement 10 and the arrangement of first attachment oil passage 100 relative to work implement 10 when the length of offset cylinder 22 is at its minimum are shown in Figure 4.

[0074] As the length that rod 22B protrudes from cylinder tube 22A increases, offset cylinder 22 extends, second boom 12 tilts to the left relative to first boom 11, and arm 14 and bucket 15 are offset to the left relative to first boom 11. The arrangement of work implement 10 and the arrangement of first attachment oil passage 100 relative to work implement 10 when the length of offset cylinder 22 is at its maximum are shown in Figure 5.

[0075] 4 and 5, when viewing the second boom 12 from the left side, the first attachment oil passage 100 overlaps with the rod 22B of the offset cylinder 22. Specifically, of the first attachment oil passage 100, a portion of the third pipe section 130 and a portion of the fourth hose section 140 (not shown in FIGS. 4 and 5) overlap with a portion of the rod 22B of the offset cylinder 22, regardless of the amount of extension or contraction of the offset cylinder 22. The third pipe section 130 and the fourth hose section 140 are disposed closer to the left side surface 12L of the second boom 12 than the rod 22B of the offset cylinder 22.

[0076] Figure 6 is a side view showing the arrangement of the arm cylinder 23 relative to the second boom 12 when the arm 14 is dumped. The arm cylinder 23 has an opposing surface 23S. The opposing surface 23S faces the upper surface 12U of the second boom 12 when the entire work implement 10 is arranged to extend substantially in the front-to-rear direction (see also Figures 1 and 5). Equipment is attached to the opposing surface 23S. Specifically, a fall prevention valve 28 is attached to the opposing surface 23S. A valve oil passage 310 that supplies pilot pressure oil to the fall prevention valve 28 is connected to the fall prevention valve 28.

[0077] The fall prevention valve 28 prevents hydraulic oil from leaking from the arm cylinder 23 in the event that hydraulic oil leaks from the arm hydraulic oil passage 300. Maintaining the hydraulic pressure in the arm cylinder 23 prevents the arm 14 from operating. This prevents the bucket 15 from falling freely. When the hydraulic excavator 1 is used with arm crane specifications that allow a load to be hoisted at the tip of the arm 14, the load is prevented from moving unexpectedly.

[0078] 6, compared to FIG. 1, the arm 14 has moved in the dumping direction (a direction away from the revolving body 30 of the hydraulic excavator 1; clockwise around the arm connecting pin 17 when viewed from the left side in FIGS. 1 and 6). As the arm 14 moves, the arm cylinder 23 rotates relative to the third bracket 13, with the cylinder connecting pin 27 as the center of rotation. The opposing surface 23S of the arm cylinder 23 is approaching the upper surface 12U of the second boom 12.

[0079] 1 to 3, there are portions on the upper surface 12U of the second boom 12 where the first attachment oil passage 100 and the second attachment oil passage 200 do not face each other. As shown in Fig. 6, the fall prevention valve 28 and valve oil passage 310 attached to the facing surface 23S, and the first attachment oil passage 100 and the second attachment oil passage 200 are arranged so as not to interfere with each other even when the facing surface 23S of the arm cylinder 23 approaches the upper surface 12U of the second boom 12.

[0080] The third pipe sections 130, 230 and the fourth hose sections 140, 240 have sections that extend along the left side surface 12L and right side surface 12R of the second boom 12 but do not extend along the top surface 12U of the second boom 12. The third pipe sections 130, 230 and the fourth hose sections 140, 240 have sections that do not face the top surface 12U of the second boom 12. The connecting section between the third pipe section 130 and the fourth hose section 140, and the connecting section between the third pipe section 230 and the fourth hose section 240 are arranged in approximately the same position as the fall prevention valve 28 in the longitudinal direction of the second boom 12.

[0081] The connection portion between the third pipe portion 130 and the fourth hose portion 140 is disposed along the left side surface 12L of the second boom 12, and is disposed opposite the left side surface 12L. The connection portion between the third pipe portion 230 and the fourth hose portion 240 is disposed along the right side surface 12R of the second boom 12, and is disposed opposite the right side surface 12R. The connection portion between the third pipe portions 130, 230 and the fourth hose portions 140, 240 does not face the top surface 12U of the second boom 12. This ensures space on the top surface 12U of the second boom 12 so that the fall prevention valve 28 and the valve oil passage 310 can move without interfering with other equipment when the arm cylinder 23 rotates about the cylinder connecting pin 27.

[0082] Although some of the description overlaps with the above description, the characteristic configuration and effects of the hydraulic excavator 1 of this embodiment can be summarized as follows.

[0083] As shown in Fig. 1, the hydraulic excavator 1 is equipped with a first attachment oil passage 100. As shown in Figs. 2 and 3, the second boom 12 has an upper surface 12U facing upward and a left side surface 12L facing leftward. The first attachment oil passage 100 is disposed so as to extend downward from the upper surface 12U of the second boom 12 along the left side surface 12L, and further extend upward from the left side surface 12L beyond the upper surface 12U.

[0084] If the attachment oil passage were arranged along the upper surface 12U over the entire second boom 12, a large slack portion would be provided in the attachment oil passage to absorb left and right movement that accompanies the offset of the work implement 10. This slack portion could interfere with other parts of the work implement 10, or the slack portions could come into contact with each other.

[0085] In the hydraulic excavator 1 of this embodiment, the first attachment oil passage 100 for supplying hydraulic oil to the attachment is arranged three-dimensionally around the second boom 12. When the work implement 10 is offset, the first attachment oil passage 100 itself deforms three-dimensionally, making it possible to easily absorb movement to the left and right. The amount of deformation of the first attachment oil passage 100 is also reduced. This eliminates the need to provide slack in the first attachment oil passage 100, making it possible to appropriately position the first attachment oil passage 100 using the shortest route. In addition, the maneuverability and maintainability of the first attachment oil passage 100 can be improved.

[0086] 2 and 3, the first attachment oil passage 100 has a third pipe section 130 and a fourth hose section 140. The third pipe section 130 extends downward from the top surface 12U of the second boom 12 along the left side surface 12L. The fourth hose section 140 extends upward from the left side surface 12L of the second boom 12, past the top surface 12U. The third pipe section 130 and the fourth hose section 140 enable the first attachment oil passage 100 to be reliably arranged so as to extend downward from the top surface 12U of the second boom 12 along the left side surface 12L, and further extend upward from the left side surface 12L, past the top surface 12U.

[0087] 2 and 3, the third pipe section 130 and the fourth hose section 140 are connected to each other. The fourth hose section 140 is arranged further from the rotating body 30 than the third pipe section 130. By arranging the third pipe section 130 along the second boom 12 and the fourth hose section 140 at the tip of the second boom 12, the flexible fourth hose section 140 can be deformed when the work implement 10 is offset, making it possible to easily absorb left and right movement.

[0088] 1 to 3, the fourth hose section 140 extends across the second offset pin 20, which is the connection between the second boom 12 and the third bracket 13. When the work implement 10 is offset, and the third bracket 13 rotates left or right relative to the second boom 12 around the second offset pin 20, the flexible fourth hose section 140 is arranged to straddle the second offset pin 20, so that the fourth hose section 140 can be deformed to easily absorb the left or right movement.

[0089] 5 and 6, the arm cylinder 23 has an opposing surface 23S that faces the upper surface 12U of the second boom 12. On the opposing surface 23S of the arm cylinder 23, a device is attached.

[0090] By attaching the equipment to the opposing surface 23S rather than the upper surface of the arm cylinder 23, contact of the equipment with the outside is suppressed. When the arm 14 is moved forward as shown in FIG. 6, the bottom side of the arm cylinder 23 approaches the upper surface 12U of the second boom 12. The first attachment oil passage 100 in this embodiment extends downward from the upper surface 12U of the second boom 12 along the left side surface 12L. A portion where the first attachment oil passage 100 is not arranged is formed along the upper surface 12U of the second boom 12. In this way, an arrangement can be achieved in which the equipment attached to the arm cylinder 23 does not interfere with the first attachment oil passage 100.

[0091] 5 and 6, by attaching the fall prevention valve 28 to the opposing surface 23S of the arm cylinder 23, the fall prevention valve 28 can be protected from the outside and interference between the fall prevention valve 28 and the first attachment oil passage 100 can be avoided. Therefore, even if a malfunction occurs in the arm operating oil passage 300, operation of the arm 14 can be reliably prevented.

[0092] 4 and 5, the offset cylinder 22 has a cylinder tube 22A and a rod 22B. The rod 22B is supported by the cylinder tube 22A so as to be able to move back and forth relative to the cylinder tube 22A in the longitudinal direction of the cylinder tube 22A. When the second boom 12 is viewed from the left side, the first attachment oil passage 100 and the rod 22B overlap. The extension and contraction of the offset cylinder 22 causes the distance between the left side surface 12L of the second boom 12 and the offset cylinder 22 to vary, but by locating the first attachment oil passage 100 between the left side surface 12L of the second boom 12 and the rod 22B, interference between the first attachment oil passage 100 and the offset cylinder 22 can be prevented.

[0093] 1 and 7, the hydraulic excavator 1 includes an attachment cylinder 24 that extends and retracts to change the position of the attachment (bucket 15, breaker 15A) relative to the arm 14, and a cylinder oil passage 320 that supplies hydraulic oil to the attachment cylinder 24. By providing the first attachment oil passage 100 and the cylinder oil passage 320 as separate components and locating the first attachment oil passage 100 and the cylinder oil passage 320 in different positions, a configuration can be achieved in which even if vibrations occur in the first attachment oil passage 100 when the attachment is in operation, the cylinder oil passage 320 is not affected, and the reliability of the cylinder oil passage 320 can be improved.

[0094] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0095] 1 hydraulic excavator, 10 work equipment, 11 first boom, 12 second boom, 12B underside, 12L left side, 12R right side, 12U top, 13 third bracket, 14 arm, 15 bucket, 15A breaker, 17 arm connecting pin, 18 attachment connecting pin, 19 first offset pin, 20 second offset pin, 21 boom cylinder, 22 offset cylinder, 22A cylinder tube, 22B rod, 23 arm cylinder, 23S opposing surface, 24 attachment cylinder, 25 link rod, 27 cylinder connecting pin, 28 fall prevention valve, 30 rotating body, 31 rotating frame, 32 cab, 34 engine room, 40 running body, 42 tracks, 44 running motor, 50 blade, 100 first attachment oil passage, 110, 210 First pipe section, 120, 220; second hose section, 130, 230; third pipe section, 140, 240; fourth hose section, 150, 250; fifth pipe section, 160, 260; sixth hose section, 170, 270; seventh pipe section, 180; eighth hose section, 200; second attachment oil passage, 300; arm operating oil passage, 310; valve oil passage, 320; cylinder oil passage.

Claims

1. The car body and a first boom connected to the vehicle body so as to be rotatable in the vertical direction; a second boom connected to a tip of the first boom so as to be rotatable in the left-right direction relative to the first boom; a bracket connected to a tip of the second boom so as to be rotatable in the left-right direction relative to the second boom; an arm connected to the bracket so as to be rotatable in the vertical direction; an attachment oil passage that supplies hydraulic oil to an attachment that can be connected to the tip of the arm; the outer surface of the second boom has an upper surface facing upward and a side surface facing laterally; The attachment oil passage is arranged to extend downward from the upper surface along the side surface, and further extend upward from the side surface beyond the upper surface.

2. The work machine according to claim 1 , wherein the attachment oil passage has a pipe portion extending downward from the upper surface along the side surface, and a hose portion extending upward from the side surface beyond the upper surface.

3. The work machine according to claim 2 , wherein the pipe portion and the hose portion are connected, and the hose portion is disposed farther from the vehicle body than the pipe portion.

4. The work machine according to claim 2 or 3, wherein the hose portion extends across a connection portion between the second boom and the bracket.

5. an arm cylinder that moves the arm up and down relative to the bracket by extending and contracting and has an opposing surface that faces the upper surface; The work machine according to claim 1 , further comprising: a device attached to the opposing surface.

6. The work machine according to claim 5 , wherein the device is a fall prevention valve that prevents the arm from operating.

7. An offset cylinder is further provided which extends and contracts to move the second boom left and right relative to the first boom, the offset cylinder has a cylinder tube and a rod supported by the cylinder tube so as to be reciprocable relative to the cylinder tube in a longitudinal direction of the cylinder tube, The work machine according to any one of claims 1 to 6, wherein the attachment oil passage and the rod overlap when the second boom is viewed from the side.

8. an attachment cylinder that expands and contracts to change the attitude of the attachment relative to the arm; The work machine according to any one of claims 1 to 7, further comprising: a cylinder oil passage that supplies hydraulic oil to the attachment cylinder.

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