JP7767201B2 - Work machinery - Google Patents

Description

This disclosure relates to a work machine.

JP 2005-61041 A (Patent Document 1) discloses that in a hydraulic excavator equipped with a work implement that performs offset operation, the attachment piping that supplies hydraulic oil to an attachment attached to the tip of the stick is arranged from the lower boom member to the upper boom member, the cylinder support member, and along one side of the stick, and a regular tube is arranged from the tip of the attachment hydraulic hose over the back of the stick to the other side of the stick.

Japanese Patent Application Laid-Open No. 2005-61041

In work machines where a hydraulically driven attachment can be connected to the tip of the work equipment, it is necessary to properly position the oil passages for supplying hydraulic oil to the attachment all the way to the tip of the work equipment.

This disclosure proposes a work machine that allows for the appropriate placement of oil passages for supplying hydraulic oil to attachments.

In accordance with the present disclosure, a work machine is proposed that includes 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.

The work machine disclosed herein allows for appropriate placement of oil passages for supplying hydraulic oil to the attachment.

FIG. 1 is a side view of a hydraulic excavator. FIG. 10 is a perspective view showing the arrangement of attachment oil passages for the second boom. FIG. 10 is a perspective view seen from a different angle showing the arrangement of attachment oil passages relative to the second boom. FIG. 10 is a side view of the second boom when the second boom is offset to the right. FIG. 10 is a side view of the second boom when the second boom is offset to the left. FIG. 10 is a side view showing the arrangement of the arm cylinder relative to the second boom when the arm is dumped. FIG. 2 is a side view showing an attachment attached to the tip of the arm.

The following describes the embodiments with reference to the accompanying drawings. In the following description, identical components are designated by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions of them will not be repeated.

Figure 1 is an external view of a hydraulic excavator 1 as an example of a work machine based on an embodiment. In this embodiment, an offset hydraulic excavator 1 will be used as an example of a work machine.

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.

When the hydraulic excavator 1 is operating, the running body 40, more specifically the tracks 42, is in contact with the ground. The running body 40 can move on the ground by rotating the tracks 42. Note that the running body 40 may have wheels (tires) instead of the tracks 42.

The running body 40 has a blade 50. The blade 50 is installed in front of the tracks 42 and extends in the width direction of the hydraulic excavator 1. The blade 50 is attached to a frame that supports the tracks 42. Using the blade 50, the hydraulic excavator 1 can perform earth removal work, ground leveling work, and other tasks.

The rotating unit 30 is placed on and supported by the running unit 40. The rotating unit 30 is movable relative to the running unit 40. The rotating unit 30 has a rotating frame 31.

The swivel frame 31 is attached to the running body 40 via a swivel circle portion. The swivel circle portion is located approximately in the center of the vehicle 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 operation 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.

The swivel frame 31 is mounted on the running body 40 so that it can rotate 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, allowing the swivel frame 31 to rotate relative to the running body 40.

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 and operates the hydraulic excavator 1. The cab 32 is located on the left side of the work implement 10. The cab 32 and work implement 10 are arranged side by side on the left and right.

The cab 32 is provided with a driver's seat where the 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, rotate the rotating unit 30 relative to the running unit 40, and control the running of the hydraulic excavator 1 using the running unit 40. In this disclosure, the hydraulic excavator 1 is operated from within the cab 32, but it may also be remotely controlled wirelessly from a location away from the hydraulic excavator 1.

In this embodiment, the positional relationship of each part of the hydraulic excavator 1 will be described using the operator seated in the driver's seat inside the cab 32 as a reference. The fore-and-aft direction refers to the fore-and-aft 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-right direction refers to the left-and-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-and-down direction refers to the up-and-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.

In the fore-and-aft direction, the side where the work implement 10 protrudes from the rotating body 30 is the front direction, and the direction opposite the front direction is the rear direction. Looking forward, the right and left sides in the left-right direction are the right and left directions, respectively. In the up-and-down direction, the side with the ground is the bottom side, and the side with the sky is the top side.

The rotating unit 30 has an engine room 34 that houses an engine, and a counterweight located at the rear of the rotating unit 30. The engine room 34 houses 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.

The work machine 10 is mounted on and supported by the rotating unit 30. The work machine 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.

The work machine 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 hydraulic cylinders driven by hydraulic oil. Hydraulic oil is supplied to the hydraulic cylinders from a hydraulic pump housed in the engine compartment 34 and driven by the engine.

The base end of the first boom 11 is connected to the rotating unit 30 via a boom foot pin (not shown) so that it can rotate up and down. A boom cylinder 21 connects the tip end of the first boom 11 to the rotating 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 up and down relative to the rotating unit 30 around the boom foot pin.

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 left and right 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 left and right relative to the second boom 12 around the second offset pin 20.

The tip of the first boom 11 and the third bracket 13 are connected by a link rod 25. The link rod 25 and offset cylinder 22 are located 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 left and right (offset) relative to the first boom 11.

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 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 bucket 15 to the left. By extending and contracting the offset cylinder 22, the second boom 12 rotates relative to the first boom 11 around the first offset pin 19, moving left and right.

The base end of the arm 14 is connected to the third bracket 13 via the arm connecting pin 17 so that it can rotate up and down. The arm cylinder 23 has a cylinder tube connected to the third bracket 13 via the 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 up and down relative to the third bracket 13 around the arm connecting pin 17.

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.

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

A cylinder oil passage 320 is connected to the attachment cylinder 24. The cylinder oil passage 320 is a hydraulic oil path 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 via the cylinder oil passage 320 and is supplied to the attachment cylinder 24.

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, obstacles are prevented from coming into contact with the cylinder oil passage 320.

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

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, changing the position of the breaker 15A relative to the arm 14.

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, while the other is a flow path for hydraulic oil returning from the attachment to the hydraulic pump. In the case where the attachment is the breaker 15A shown in Figure 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.

Figures 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 area around the connection between the second boom 12 and the third bracket 13, viewed from different angles.

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 (Figure 6) facing downward, a left side surface 12L facing left, and a right side surface 12R facing right.

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 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. When 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.

As the first boom 11 rotates relative to the revolving unit 30, the second boom 12 also rotates vertically relative to the revolving unit 30. The upper surface 12U and lower surface 12B may be positioned so as to be inclined relative to the vertical direction depending on changes in the posture of the work machine 10.

The left side surface 12L and the right side surface 12R are outer surfaces of the second boom 12 that are opposite 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.

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

The first attachment oil passage 100 has 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 metallic 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.

The first pipe section 110, the third pipe section 130, the fifth pipe section 150, and the seventh pipe section 170 are rigid. The first pipe section 110, the third pipe section 130, the fifth pipe section 150, and the seventh pipe section 170 are arranged along one of the link members that make up the work machine 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 machine 10 is in operation.

The second hose section 120, fourth hose section 140, and sixth hose section 160 are flexible. The second hose section 120, fourth hose section 140, and sixth hose section 160 are arranged at the joints that connect the link members that make up the work machine 10. The second hose section 120, fourth hose section 140, and sixth hose section 160 are provided in locations of the first attachment oil passage 100 that experience significant deformation when the work machine 10 is in operation.

Specifically, the first pipe section 110 is arranged to extend along the outer surface of the first boom 11. The first pipe section 110 is arranged along the upper surface of the first boom 11.

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 rotating unit 30 than the first pipe section 110. Note that 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 rotating 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 attachment is located) 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 the arm connecting pin 17. The distal end of the arm 14 is the tip of the arm 14 where an attachment (bucket 15, breaker 15A, etc.) is connected to the arm 14 via the attachment connecting pin 18. Depending on the posture 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.

The second hose section 120 is arranged from the first boom 11 to the second boom 12. The second hose section 120 extends from the tip of the first boom 11 toward the second boom 12, straddling the first offset pin 19, which is the connection between the first boom 11 and the second boom 12. The second hose section 120 extends along the upper surface of the first boom 11, passes over the first offset pin 19, and is arranged to extend along the upper surface 12U of the second boom 12.

The 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 arranged farther from the rotating body 30 than the second hose section 120. The third pipe section 130 is arranged along the upper surface 12U of the second boom 12, then curves to the left and follows 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.

The proximal end of the fourth hose section 140 is connected to the distal end of the third pipe section 130. In the direction extending along the work implement 10, the fourth hose section 140 is arranged farther from the rotating body 30 than the third pipe section 130. The fourth hose section 140 is arranged 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 the second offset pin 20, which is the connection section between 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 extends upward along the left side surface 12L of the second boom 12, turns to the right, extends in the longitudinal direction of the second boom 12, passes over the second offset pin 20, and is arranged to extend inside the third bracket 13.

As shown in FIG. 1 and FIG. 6 described below, a portion of the fourth hose section 140 that is above the upper surface 12U of the second boom 12 has a portion that is positioned farther from the upper surface 12U of the second boom 12 than a portion 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 portion 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 portion of the third pipe section 130 that is above the upper surface 12U and the upper surface 12U.

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, extending in the left-right direction.

The proximal end of the sixth hose section 160 is connected to the distal end of the fifth pipe section 150. In the direction extending along the work implement 10, the sixth hose section 160 is arranged farther from the rotating body 30 than the fifth pipe section 150. The sixth hose section 160 is arranged 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 the arm connecting pin 17, which is the connecting section between the third bracket 13 and the arm 14. The sixth hose section 160 is arranged so as to extend along the left side of the third bracket 13, beyond the arm connecting pin 17, and along the left side of the arm 14.

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 arranged farther from the rotating body 30 than the sixth hose section 160. The sixth hose section 160 is gently curved overall 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 arranged along the left side of the arm 14.

The first attachment oil passage 100 further includes 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 toward the breaker 15A, straddling the attachment connecting pin 18, which connects the arm 14 and the breaker 15A.

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.

The first pipe section 210, the third pipe section 230, the fifth pipe section 250, and the seventh pipe section 270 are rigid. The first pipe section 210, the third pipe section 230, the fifth pipe section 250, and the seventh pipe section 270 are arranged along one of the link members that make up the work machine 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 minimal deformation even when the work machine 10 is in operation.

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

Specifically, the first pipe section 210 is arranged to extend along the outer surface of the first boom 11. The first pipe section 210 is arranged along the upper surface of the first boom 11.

The 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 arranged farther from the rotating body 30 than the first pipe section 210. The second hose section 220 is arranged 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 the first offset pin 19, which connects the first boom 11 and second boom 12. The second hose section 220 is arranged 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.

The 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 arranged farther from the rotating body 30 than the second hose section 220. The third pipe section 230 is arranged along the upper surface 12U of the second boom 12, then curves to the right and follows 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.

The proximal end of the fourth hose section 240 is connected to the distal end of the third pipe section 230. In the direction extending along the work implement 10, the fourth hose section 240 is arranged farther from the rotating body 30 than the third pipe section 230. The fourth hose section 240 is arranged from the second boom 12 to the third bracket 13. The fourth hose section 240 straddles the second offset pin 20, which is the connection section between the second boom 12 and the third bracket 13, and extends from the tip of the second boom 12 toward the third bracket 13. The fourth hose section 240 extends upward from the right side surface 12R of the second boom 12, past the top surface 12U. The fourth hose section 240 extends upward along the right side surface 12R of the second boom 12, turns to the left, extends in the longitudinal direction of the second boom 12, passes over the second offset pin 20, and is arranged to extend inside the third bracket 13.

As shown in FIG. 1 and FIG. 6 described below, a portion of the fourth hose section 240 that is above the upper surface 12U of the second boom 12 has a portion that is positioned farther from the upper surface 12U of the second boom 12 than a portion 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 portion 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 portion of the third pipe section 230 that is above the upper surface 12U and the upper surface 12U.

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, extending in the left-right direction.

The proximal end of the sixth hose section 260 is connected to the distal end of the fifth pipe section 250. In the direction extending along the work implement 10, the sixth hose section 260 is arranged farther from the rotating body 30 than the fifth pipe section 250. The sixth hose section 260 is arranged 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 the connecting section between the third bracket 13 and the arm 14. The sixth hose section 260 is arranged to extend along the right side of the third bracket 13, past the arm connecting pin 17, and along the right side of the arm 14.

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 arranged farther from the rotating body 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 arranged along the right side of the arm 14.

Although not shown, the second attachment oil passage 200 further includes 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 connects the arm 14 and the breaker 15A.

The first attachment oil passage 100 and the second attachment oil passage 200 form a three-dimensional path 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 positioned facing 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 positioned facing the left side surface 12L and 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 between the third pipe section 130 and the fourth hose section 140. The second attachment oil passage 200 is bent at the connection between the third pipe section 230 and the fourth hose section 240.

The first attachment oil passage 100 and the second attachment oil passage 200 are arranged to extend along the entire length of the 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.

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

Figure 4 is a view of the second boom 12 from the left side when the second boom 12 is offset to the right. Figure 5 is a view of the second boom 12 from the left side when the second boom 12 is offset to the left.

As shown in Figures 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 inside. 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 located outside the cylinder tube 22A and connected to the third bracket 13. The rod 22B is positioned to penetrate the end face of the cylinder tube 22A and is capable of reciprocating movement relative to the cylinder tube 22A in the longitudinal direction of the cylinder tube 22A.

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.

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

As the length of the rod 22B protruding from the cylinder tube 22A increases, the offset cylinder 22 extends, the second boom 12 tilts to the left relative to the first boom 11, and the arm 14 and bucket 15 are offset to the left relative to the first boom 11. Figure 5 shows the position of the work implement 10 and the position of the first attachment oil passage 100 relative to the work implement 10 when the length of the offset cylinder 22 is at its maximum.

As shown in Figures 4 and 5, when viewing the second boom 12 from the left side, the first attachment oil passage 100 and the rod 22B of the offset cylinder 22 overlap. 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 Figures 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 arranged closer to the left side surface 12L of the second boom 12 than the rod 22B of the offset cylinder 22.

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 positioned so that it extends substantially in the fore-and-aft 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.

The fall prevention valve 28 prevents hydraulic oil from leaking from the arm cylinder 23 in the event of hydraulic oil leakage from the arm hydraulic oil passage 300. Maintaining hydraulic pressure within 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 suspended from the tip of the arm 14, unexpected movement of the load is prevented.

In the arrangement shown in FIG. 6, compared to FIG. 1, the arm 14 has moved in the dumping direction (a direction away from the rotating 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.

As explained with reference to Figures 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 Figure 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 second attachment oil passage 200 are positioned so that they do not 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.

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

The connection between the third pipe section 130 and the fourth hose section 140 is disposed along the left side surface 12L of the second boom 12, facing the left side surface 12L. The connection between the third pipe section 230 and the fourth hose section 240 is disposed along the right side surface 12R of the second boom 12, facing the right side surface 12R. The connection between the third pipe sections 130, 230 and the fourth hose sections 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 valve oil passage 310 can move without interfering with other equipment when the arm cylinder 23 rotates around the cylinder connecting pin 27.

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

As shown in Figure 1, the hydraulic excavator 1 is equipped with a first attachment oil passage 100. As shown in Figures 2 and 3, the second boom 12 has an upper surface 12U facing upward and a left side surface 12L facing left. The first attachment oil passage 100 is arranged 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.

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 the left and right movement that occurs when the work implement 10 is offset. This slack portion could interfere with other parts of the work implement 10, or the slack portions could come into contact with each other.

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 easy to 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, allowing the first attachment oil passage 100 to be appropriately positioned using the shortest route. In addition, the maneuverability and maintainability of the first attachment oil passage 100 can be improved.

As shown in Figures 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 ensure that the first attachment oil passage 100 extends downward from the top surface 12U of the second boom 12 along the left side surface 12L, and further extends upward from the left side surface 12L, past the top surface 12U.

As shown in Figures 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 positioned further away from the rotating body 30 than the third pipe section 130. By positioning 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, easily absorbing left and right movement.

As shown in Figures 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 positioned to straddle the second offset pin 20, so that the fourth hose section 140 can be deformed to easily absorb left or right movement.

As shown in Figures 5 and 6, the arm cylinder 23 has an opposing surface 23S that faces the upper surface 12U of the second boom 12. Equipment is attached to the opposing surface 23S of the arm cylinder 23.

Attaching the equipment to the opposing surface 23S rather than the top surface of the arm cylinder 23 prevents the equipment from coming into contact with the outside. As shown in FIG. 6 , when the arm 14 is moved forward, the bottom side of the arm cylinder 23 approaches the top surface 12U of the second boom 12. In this embodiment, the first attachment oil passage 100 extends downward from the top surface 12U of the second boom 12 along the left side surface 12L. A portion where the first attachment oil passage 100 is not located is formed along the top surface 12U of the second boom 12. In this way, it is possible to achieve an arrangement where the equipment attached to the arm cylinder 23 does not interfere with the first attachment oil passage 100.

As shown in Figures 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.

As shown in Figures 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 that it can 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 distance between the left side surface 12L of the second boom 12 and the offset cylinder 22 changes as the offset cylinder 22 extends and retracts. However, 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.

As shown in Figures 1 and 7, the hydraulic excavator 1 is equipped with 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, it is possible to create a configuration in which vibrations occurring in the first attachment oil passage 100 during attachment operation do not affect the cylinder oil passage 320, thereby improving the reliability of the cylinder oil passage 320.

The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims, not the above description, and is intended to include all modifications that are equivalent in meaning to and within the scope of the claims.

1 Hydraulic excavator, 10 Work machine, 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 Opposite surface, 24 Attachment cylinder, 25 Link rod, 27 Cylinder connecting pin, 28 Fall prevention valve, 30 Swing body, 31 Swing frame, 32 Cab, 34 Engine room, 40 Running body, 42 Track, 44 Travel 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 (8)

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. The work machine described in 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. The work machine described in 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. A work machine as described in claim 2 or claim 3, wherein the hose portion extends across the connection portion between the second boom and the bracket. 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. The work machine described in claim 5, wherein the device is a fall prevention valve that prevents the arm from operating. 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 includes 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. 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.