阅读说明：本技术 建筑机器中的油脂供给管道布置结构 (Grease supply pipe arrangement structure in construction machine ) 是由 宫田尚纪 巽耕太 古贺弘和 天谷彻 西本和史 越间哲也 伊藤宏弥 于 2020-03-02 设计创作，主要内容包括：[问题]在臂、工作附接件和可延伸缸的远端部经由动力连杆和惰轮连杆联接的建筑机器中,当油脂供给管道布置在惰轮连杆内时实现对油脂供给管道的保护,并且确保惰轮连杆的结构不复杂。[解决]在惰轮连杆(13)中,形成有从惰轮连杆(13)的连杆主体部(13a)沿与铲斗(7)相反的方向突出的突出部(13d)；设置有油脂供给管道布置空间(23),该油脂供给管道布置空间(23)在连杆长度方向上朝向突出部(13d)的左右外侧面(13e)的左右内侧延伸,并且至少与铲斗(7)相对的一侧或者左右内侧开口；并且油脂供给管道(22c)布置在油脂供给管道布置空间(23)中,在不超过突出部(13d)的突出远端部面(13f)且不超过连杆主体部(13a)的左右内侧连杆面(13g)向与铲斗(7)相反的方向突出的状态下。(In a construction machine in which an arm, a work attachment, and a distal end portion of an extendable cylinder are coupled via a power link and an idler link, protection of a grease supply conduit is achieved when the grease supply conduit is disposed within the idler link, and the structure of the idler link is ensured to be uncomplicated. [ solution ] in an idler link (13), a protruding portion (13d) protruding in the direction opposite to the bucket (7) from a link main body portion (13a) of the idler link (13) is formed; a grease supply pipe arrangement space (23) is provided, the grease supply pipe arrangement space (23) extending toward the left and right inner sides of the left and right outer side surfaces (13e) of the protruding portion (13d) in the link length direction and being open at least at the side opposite to the bucket (7) or the left and right inner sides; the grease supply pipe (22c) is arranged in the grease supply pipe arrangement space (23) in a state in which the grease supply pipe does not protrude beyond the protruding distal end surface (13f) of the protruding portion (13d) and beyond the right and left inner link surfaces (13g) of the link main body portion (13a) in a direction opposite to the bucket (7).)

1. A grease supply pipe arrangement structure in a construction machine, comprising:

a work attachment pivotally supported at a distal end portion of the arm so as to be freely swingable via a first pin;

an extendable cylinder supported at its proximal end by the arm, configured to extend and retract so as to cause the work attachment to swing;

a power link pivotally supported at one end thereof by the work attachment so as to be freely swingable via a second pin, and pivotally supported at the other end thereof at a distal end portion of the extendable cylinder so as to be freely swingable via a third pin; and

a pair of left and right idler links pivotally supported at one end thereof so as to be freely swingable via the third pin pivotally supporting the other end of the power link and the distal end portion of the extendable cylinder, and pivotally supported at the other end thereof on left and right side face portions of the arm so as to be freely swingable via a fourth pin,

wherein the idler link is configured to have a flat plate-like link main body portion, pin holes for the third pin and the fourth pin being formed on both end sides of the link main body portion when a grease supply pipe is arranged in the idler link; forming a protrusion that protrudes from the link main body portion in a direction opposite to the work attachment by extending a link width of the link main body portion in the direction opposite to the work attachment; providing a grease supply pipe arrangement space which extends in the connecting rod length direction on the left and right inner sides of the left and right outer side faces of the protruding portion and is open on at least one of the left and right inner sides or on the side opposite to the work attachment; and arranging the grease supply pipe in the grease supply pipe arrangement space in a state where it does not protrude beyond the protruding distal end face of the protruding portion and does not protrude left and right inward beyond the left and right inner link faces of the link main body portion in a direction opposite to the work attachment.

2. The grease supply pipe arrangement structure for a construction machine according to claim 1, wherein the grease supply pipe arrangement space is formed in a shape that is obliquely cut out from the projecting distal end face of the projecting portion toward right and left inner link faces of the link main body portion, and that is open on the opposite side and right and left inner sides from the work attachment.

3. The grease supply duct arrangement structure of a construction machine according to claim 1, wherein the grease supply duct space is formed in a shape that cuts out an L-shape from the projecting distal end face of the projecting portion toward right and left inner link faces of the link main body portion, and that is open on the side opposite to the work attachment and on the right and left inner sides.

4. The grease supply pipe arrangement structure of a construction machine according to claim 1, wherein the grease supply pipe space is formed in a groove shape recessed into the projecting distal end face of the projecting portion, and is open to an opposite side of the work attachment.

5. The grease supply duct arrangement structure of a construction machine according to claim 1, wherein the grease supply duct space is formed in a groove shape recessed into left and right side faces of the protruding portion, and left and right inner sides are opened.

6. The grease supply pipe arrangement structure of a construction machine according to any one of claims 1 to 5, wherein pipe fixing portions for fixing the grease supply pipe are provided at both end portions of the grease supply pipe space in the link length direction.

7. The grease supply duct arrangement structure of a construction machine according to any one of claims 1 to 6, wherein the grease supply duct arranged within the grease supply duct space of the idler link is configured to be coupled to a distribution valve provided on an arm-opposite side link face of the power link, and to supply grease from the distribution valve to one end portion and the other end portion of the power link.

Technical Field

The present invention relates to the technical field of a grease supply pipe arrangement in a construction machine such as a hydraulic excavator.

Background

In general, for example, in construction machines such as hydraulic excavators, there are front working units configured such that a front working unit mounted on a machine main body includes an arm, a bucket pivotally supported so as to be freely swingable at a distal end portion of the arm, and some of bucket cylinders configured to extend and retract so as to be supported at proximal end portions thereof by the arm swing the bucket, and the arm and the bucket and the distal end portions of the bucket cylinders are coupled by a link mechanism including a power link pivotally supported at one end portion thereof so as to enable the bucket to freely swing, and pivotally supported at the other end portion thereof so as to enable distal end portions of the bucket cylinders to freely swing; and an idler link pivotally supported at one end thereof so as to be freely swingable on a shaft supporting portion formed on the other end of the power link and the distal end portion of the bucket cylinder, and pivotally supported at the other end thereof so as to be freely swingable by the arm.

Meanwhile, in a device in which a plurality of members are pivotally supported so as to be able to swing, such as a front working unit of a hydraulic excavator, it is necessary to periodically supply grease to these shaft supporting portions. However, if the vehicle size of the construction machine is large and thus it is difficult to access the shaft supports from the ground, the distance between the shaft supports is large, or there are many shaft supports, the oiling work becomes complicated and time-consuming. Therefore, conventionally, there have been known a concentrated grease injection system in which grease nozzles are arranged in a concentrated manner at positions easily accessible to a vehicle, and grease supply pipes are arranged from the grease nozzles arranged in a concentrated manner to the respective shaft support portions to supply grease, and an automatic grease injection system in which a grease injection pump is mounted on the vehicle, a distribution valve is provided at an appropriate position, the pump is operated at a predetermined timing, and grease is supplied from the distribution valve to the respective shaft support portions via the grease supply pipes (see, for example, patent document 1).

In the case where the centralized grease injection system or the automatic grease injection system is employed in the front working unit of the above-described hydraulic excavator, in order to apply grease to each shaft supporting portion that pivotally supports one end portion and the other end portion of the power link, it is necessary to arrange a grease supply pipe that detours on the arm side to extend to the power link via the idler link. However, partly because the idler links disposed near the bucket may be covered with soil and sand during digging or the like, there is a problem in that the grease supply pipes disposed on the idler links may be easily damaged. Therefore, the system of patent document 1 is configured such that a hollow grease passage is formed inside the idler link, and grease is supplied to the shaft supporting portion of the power link via the grease passage inside the idler link. As another example, patent document 1 discloses an arrangement in which a recessed groove-shaped grease groove is formed in a link main body side surface portion of an idler link, and a thin plate-shaped cover covering the recessed groove is welded to the link side surface portion.

Documents of the prior art

[ patent document ]

[ patent document 1] Japanese Utility model application laid-open No. 6-53653

Disclosure of Invention

[ problem to be solved by the invention ]

However, if the arrangement in which the hollow grease passage is formed inside the idler link as in patent document 1 is adopted, there is a problem that the structure of the idler link becomes complicated and the manufacturing cost becomes excessively high. Further, as another example of patent document 1, a groove is formed on a side surface of a link of an idler link, and the groove is covered with a thin plate-like cover. At the same time, there is a fear that the risk of damage to the thin plate-shaped cover itself or the weld metal region between the cover and the connection side surface due to collision with soil and sand is high. However, if the cover itself or the welded portion of the cover is damaged, it must be repaired every time, and there is a risk that cracks or the like may occur in the idler link due to the damage of the welded portion. There is a problem that the strength of the device itself may be affected by having to be considered, and there is a problem solved by the present invention.

[ means for solving problems ]

The present invention has been made in view of the above circumstances, in order to solve these problems. According to a first aspect, the present invention is a grease supply pipe arrangement in a construction machine, comprising a work attachment pivotably supported at a distal end of an arm so as to be freely swingable via a first pin; an extendable cylinder supported by the arm at a proximal end thereof, configured to extend and retract to cause the work attachment to swing; a power link pivotally supported at one end thereof by the work attachment so as to be freely swingable via a second pin, and is pivotally supported at the other end thereof at the distal end portion of the extendable cylinder so as to be freely swingable via a third pin shaft, pivotally supported at one end portion thereof by the third pin shaft in a freely swingable manner, the third pin shaft pivotally supporting the other end portion of the power link and the distal end portion of the extendable cylinder, and pivotally supported at the other end portion thereof on right and left side face portions of an arm, which is freely swingable via a fourth pin shaft, wherein when a grease supply pipe is provided in the idler link, the idler link is configured to have a flat-plate-shaped link body portion having pin holes formed for the third pin and the fourth pin on both end sides; forming a protrusion that protrudes from the link main body portion in a direction opposite to the work attachment by extending a link width of the link main body portion in the direction opposite to the work attachment; providing a grease supply pipe arrangement space which extends in the connecting rod length direction on the left and right inner sides of the left and right outer side faces of the protruding portion and is open on at least one of the left and right inner sides or on the side opposite to the work attachment; and arranging the grease supply pipe in the grease supply pipe arrangement space in a state where it does not protrude beyond the protruding distal end face of the protruding portion and does not protrude left and right beyond the left and right inner link faces of the link main body portion in a direction opposite to the work attachment.

A grease supply pipe arrangement in a construction machine according to a second aspect of the invention is the grease supply pipe arrangement in the construction machine according to the first aspect, wherein the grease supply pipe arrangement space is formed in a shape that is obliquely cut out from the projecting distal end portion of the projecting portion toward the right and left inner link faces of the link main body portion, and that is open on the opposite side and the right and left inner sides from the work attachment.

A grease supply pipe arrangement in a construction machine according to a third aspect of the invention is the grease supply pipe arrangement in the construction machine according to the first aspect, wherein the grease supply pipe space is formed in a shape that is cut out in an L shape from the projecting distal end face of the projecting portion toward the right and left inner link faces of the link main body portion, and that is opposite to the work attachment and the right and left inner openings.

A grease supply pipe arrangement in a construction machine according to a fourth aspect of the invention is the grease supply pipe arrangement in the construction machine according to the first aspect, wherein the grease supply pipe space is formed in a groove shape recessed in the projecting distal end face of the projecting portion, and is open on the side opposite to the work attachment.

A grease supply pipe arrangement in a construction machine according to a fifth aspect of the invention is the grease supply pipe arrangement in the construction machine according to the first aspect, wherein the grease supply pipe space is formed in a groove shape recessed into left and right side faces of the protruding portion, and left and right inner sides are open.

A grease supply pipe arrangement structure in a construction machine according to a sixth aspect of the present invention is the grease supply pipe arrangement structure in a construction machine according to any one of the first to fifth aspects, wherein pipe fixing portions for fixing the grease supply pipes are provided at both end portions of the grease supply pipe space in the link length direction.

A grease supply pipe arrangement in a construction machine according to a seventh aspect of the invention is the grease supply pipe arrangement in a construction machine according to any one of the first to sixth aspects, wherein the grease supply pipe arranged in the grease supply pipe space of the idler link is configured to be coupled to a distribution valve provided on an arm-opposite side link face of the power link, and to supply grease from the distribution valve to one end portion and the other end portion of the power link.

[ advantageous effects of the invention ]

According to the first aspect of the invention, the grease supply pipe provided in the grease supply pipe arranging space of the idler link can be protected, and the manufacturing cost can be suppressed without complicating the structure of the idler link.

According to the second, third, fourth, and fifth aspects of the present invention, the grease supply pipe arranging space can be simply formed, and the grease supply pipe can be arranged in such a state in the grease supply pipe arranging space as not to protrude beyond the protruding distal end portion of the protruding portion in the direction opposite to the bucket and as not to protrude inward left and right beyond the left and right inner link faces of the link main body portion.

According to the sixth aspect of the invention, it is possible to prevent the grease supply pipe provided on the idler link from being accidentally displaced.

According to the seventh aspect of the invention, the risk of breakage or failure of the distribution valve arranged on the power train can be significantly reduced.

Drawings

Fig. 1 is a side view of a hydraulic excavator.

Fig. 2 is a view showing a link mechanism portion of the connecting arm, the bucket, and the bucket cylinder.

Fig. 3A to 3D are views showing an idler link on which a grease supply pipe is disposed, in which fig. 3A is a front view, fig. 3B is an X-X end view of fig. 3A, fig. 3C is a plan view, and fig. 3D is an enlarged view of a main portion of fig. 3B.

Figure 4 is a partial perspective view of an idler link with a grease supply conduit disposed therein.

Fig. 5 is a diagram showing a power link provided with a distribution valve.

Fig. 6A, 6B, and 6C are diagrams illustrating other examples of the grease supply pipe arranging space.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, reference numeral 1 denotes a hydraulic excavator as an example of a construction machine. The hydraulic excavator 1 includes a lower traveling structure 2, an upper rotating structure 3 rotatably supported by the lower traveling structure 2 through a rotary bearing 3a, a front working unit 4 mounted on the upper rotating structure 3, and the like. The front working unit 4 further includes a boom 5, and a proximal end portion side of the boom 5 is pivotably supported by the upper swivel structure 3 so as to be swingable in a vertical (up-down) direction; an arm 6 swingably supported at a distal end portion of the arm 5; a bucket (corresponding to a work attachment of the present invention) 7 swingably supported at a distal end portion of the arm 6; the boom cylinder 8, the arm cylinder 9, and the bucket cylinder (corresponding to the extendable cylinder of the present invention) 10 extend and contract, respectively, to swing the boom 5, the arm 6, and the bucket 7.

The bucket 7 is pivotally supported at the distal end portion of the arm 6 so as to be freely swingable via a first pin 11, and the proximal end portion of the bucket cylinder 10 is swingably supported at the proximal end portion side of the arm 6. However, the distal end portion (rod distal end portion) of the bucket cylinder 10, the bucket 7, and the arm 6 are coupled by a link mechanism constituted by a power link 12 and a pair of left and right idler links 13.

The power link 12 is pivotally supported at one end thereof by the bucket 7 so as to be freely swingable via a second pin 14, and is pivotally supported at the other end thereof by the distal rod end portion of the bucket cylinder 10 so as to be freely swingable via a third pin 15. In this case, the other end portion of the power link 12 has right and left shaft supports 12a and 12a divided into two sections, and the right and left shaft supports 12a and 12a are pivotally supported by third pin shafts 15 provided on the right and left outer sides of the lever distal end portion of the bucket cylinder 10. Then, the power link 12 is configured such that one side of the link face 12c is opposed to the distal end portion of the arm 6 in a state where both end portions are supported by the second and third pins 14, 15. However, a third distribution valve 21 for grease injection (corresponding to the distribution valve provided on the arm-opposite-side link face of the power link of the present invention) described below is provided on the arm-opposite-side link face 12 c.

One end portions of the pair of left and right idler links 13 are pivotally supported in a freely swingable manner by a third pin 15, the third pin 15 supporting the other end portions of the power link 12 and the rod distal end portion of the bucket cylinder 10, and pivotally supported at their other end portions on the right and left side faces 6a of the arm 6 so as to be swingable via a fourth pin 16. In this case, one end portions of the pair of left and right idler links 13 are pivotally supported by the third pin 15 on left and right outer sides of the left and right shaft supporting portions 12a disposed on the other end portions of the power link 12, and the other end portions are pivotally supported on left and right both end portions of the fourth pin 16 protruding from the left and right side face portions 6a of the arm 6, respectively. These idler links 13 are configured so as to be opposed to a state where the bucket 7 is pivotally supported at both ends by the third and fourth pin shafts 15, 16 on one side in the link width direction. Further, in the idler link 13, a grease supply conduit arrangement space 23 is formed for arranging a grease supply conduit 22c described below, which grease supply conduit 22c extends from the arm 6 side to extend to the third distribution valve 21 arranged on the power link 12 via the idler link 13. The grease supply conduit arrangement space 23 will be described below. In the present invention, the opposite sides of the pair of left and right idler links 13 are defined as the left and right inner sides, and the opposite sides are defined as the left and right outer sides.

Next, the automatic grease supply system provided in the hydraulic excavator 1 will be described. In fig. 1, reference numeral 18 denotes a grease filling pump, 19 denotes a first distribution valve provided on the boom 5, 20 denotes a second distribution valve provided on the arm 6, and 21 denotes a third distribution valve provided on the power link 12. These distribution valves 19 to 21 are operable to relay and branch the grease supplied from the grease injection pump 18 so that the grease flows into the plurality of shaft supports provided in the hydraulic excavator 1. That is, the grease supplied from the grease pump 18 is caused to flow into the respective distribution valves 19 to 21, through the grease supply conduit 22a extending from the grease pump 18 to the first distribution valve 19, through the grease supply conduit 22b extending from the first distribution valve 19 to the second distribution valve 20, and through the grease supply conduit 22c extending from the distribution valve 20 to the third distribution valve 21, and from the respective distribution valves 19 to 21, the grease is caused to flow into the respective shaft supports through the grease supply conduits (not shown in fig. 1) extending from these respective distribution valves 19 to 21 to the respective shaft supports. In fig. 1, the grease filling pump 18, the first, second and third distribution valves 19, 20, 21 and the grease supply conduits 22a, 22b, 22c are shown in solid lines for clarity of these components.

The grease pump 18 is configured to automatically operate and supply grease under predetermined conditions, for example, at every designated time. In addition, an appropriate number of distribution valves may be arranged at appropriate positions corresponding to the size or the like of the construction machine such as a hydraulic excavator. Further, the dispensing valve may be a check valve or a dispensing valve configured to include a mouth portion that allows manual application of grease.

In the present embodiment, grease is supplied from the first distribution valve 19 to the rotary bearing 3a, the shaft support portion formed at the proximal end portion of the boom 5, the shaft support portions formed at the proximal end portion and the distal end portion of the boom cylinder 8, and the shaft support portion formed at the proximal end portion of the arm cylinder 9 via a grease supply pipe (not shown); supplying grease from the second distribution valve 20 via a grease supply pipe (not shown) to a shaft support portion formed at the distal end portion of the boom 5 and the proximal end portion of the arm 6, a shaft support portion formed at the distal end portion of the arm cylinder 9, a shaft support portion supporting the proximal end portion of the bucket cylinder 10, a shaft support portion supporting the distal end portion of the arm 6 and the bucket 7 via the first pin 11, and a shaft support portion supporting the other end portion of the idler link 13 and the arm 6 via the fourth pin 16; further, as shown in fig. 5, from the third distribution valve 21, grease is supplied via the third pin 15 to the shaft supports formed at both ends of the power link 12, that is, the shaft support 12b formed at one end of the power link 12 and the bucket 7, and the shaft support 12a formed at the other end of the power link 12 and one end of the idler link 13, via the grease supply line 22 d.

Now, as described above, the grease supply pipe 22c extending from the second distribution valve 20 provided on the arm 6 to the third distribution valve 21 provided on the power link 12 is arranged to extend from the arm 6 side to the power link 12 via the idler link 13. The idler link 13 has a grease supply conduit arrangement space 23 in which a grease supply conduit 22c is arranged. Next, the structure of the idler link 13 and the supply pipe arranging space 23 will be explained.

The idler link 13 has a flat plate-like link body portion 13 a. Pin holes 13b, 13c are formed at both end portions of the link main body portion 13a, and third and fourth pin shafts 15, 16 are inserted into the pin holes 13b, 13c, respectively. The link width of the link body portion 13a (the width in the direction perpendicular to the line connecting the central portions of the pin holes 13b, 13 c) is set to be wider than the aperture diameter of the pin holes 13b, 13 c. The link width of the link body 13a ensures a link width necessary for the strength of the idler link 13. Further, the idler link 13 is formed with a projecting portion (ear portion) 13d that projects from the link body portion 13a in a direction opposite to the bucket 7 by extending the link width of the link body portion 13a to the side opposite to the bucket 7. A grease supply pipe arrangement space 23 extending in the link longitudinal direction (the direction parallel to the line connecting the center portions of the pin holes 13b, 13 c) is provided on the left and right inner sides of the left and right outer side surfaces 13e of the protruding portion 13 d. The grease supply pipe disposing space 23 is formed in a shape obliquely cut away from the projecting distal end surface 13f of the projecting portion 13d toward the right and left inner side link surfaces 13g of the link main body portion 13a, the right and left outer sides thereof are covered with the right and left outer side surfaces 13e of the projecting portion 13d, the bucket 7 side is covered with the link main body portion 13a, and the opposite side and the right and left inner sides of the bucket 7 are open. Next, in the grease supply pipe disposing space 23, the grease supply pipe 22c is disposed in a state not protruding beyond the protruding distal end face 13f of the protruding portion 13d in the direction opposite to the bucket 7 and not protruding inward in the left and right direction beyond the left and right inner link faces 13g of the link main body portion 13 a. Therefore, if the soil and sand are not fine, the collision of the soil and sand scattered from the bucket 7 side or the left and right outer sides with the grease supply pipe 22c can be reliably prevented by the projecting portion 13d and the left and right outer side surfaces 13e of the link body 13a, and the soil and sand scattered from the opposite side or the left and right inner sides of the bucket 7 will come into contact with the projecting distal end surface 13f of the projecting portion 13d and the left and right inner link surfaces 13g of the link body 13a earlier than the grease supply pipe 22 c. This can effectively protect the grease supply pipe 22 c.

In addition, at both end portions in the link length direction of the grease supply pipe arranging space 23, pipe fixing portions 23a for fixing the grease supply pipe 22c are provided, and by fixing to the pipe fixing portions 23a, the grease supply pipe 22c arranged in the supply pipe arranging space 23 can be prevented from being displaced. The pipe fixing portion may be a support shape that supports the grease supply pipe, or may be a block shape that is embedded in an end portion of the grease supply pipe. In the case of the block shape, the pipe fixing portion may have a structure that also serves as a connector for interconnecting the grease supply pipe disposed in a portion of the grease supply pipe disposing space of the idler link with the grease supply pipes disposed at the front and rear portions of the idler link.

In the present embodiment configured as described above, the hydraulic excavator 1 includes the bucket (work attachment) 7 pivotably supported at the distal end portion of the arm 6 so as to freely swing via the first pin 11; a bucket cylinder (extendable cylinder) 10 supported and extended at its proximal end portion by the arm 6, configured to extend and retract so as to swing the bucket 7; a power link 12 pivotally supported at one end thereof by the bucket 7 so as to be freely swingable via a second pin 14, and pivotally supported at the other end thereof by a distal end portion of the bucket cylinder 10 so as to be freely swingable via a third pin 15; and a pair of left and right idler links 13 pivotally supported at one end portions thereof so as to be freely swingable via the third pin shafts 15 pivotally supporting the other end portions of the power links 12, and pivotally supported at the other end portions thereof on left and right side face portions 6a of the arms 6 so as to be freely swingable via fourth pin shafts 16, wherein the idler links 13 have flat plate-like link main body portions 13a in which pin holes 13b, 13c for the third and fourth pin shafts 15, 16 are formed on both end sides when the grease supply pipe 22c is disposed in the idler links 13, and further formed with projecting portions 13d projecting from the link main body portions 13a in the direction opposite to the bucket 7 by extending the link width of the link main body portions 13a in the direction opposite to the bucket 7. Further, in the left and right inner sides of the left and right outer side surfaces 13e of the protruding portion 13d, a grease supply pipe arrangement space 23 is provided, the grease supply pipe arrangement space 23 extending in the link length direction and having a shape opening to at least either one of the side opposite to the bucket 7 or the left and right inner sides, and in the grease supply pipe arrangement space 23, the grease supply pipe 22c is arranged so as not to protrude beyond the protruding distal end surface 13f of the protruding portion 13d in the direction opposite to the bucket 7 and so as not to protrude inward in the left and right direction beyond the left and right inner connecting face 13g of the link main body portion 13 a.

Thus, the left and right outer sides of the grease supply pipe 22c disposed in the grease supply pipe disposition space 23 are covered with the left and right outer side surfaces 13e of the projecting portions 13d, and the bucket 7 side thereof is covered with the link body portion 13a, so that it is possible to reliably prevent earth and sand or the like scattered from the bucket 7 side or the left and right outer sides from colliding with the grease supply pipe 22 c. On the other hand, even if the soil and sand or the like is scattered from the side facing the bucket 7 or the right and left inner sides, although less than the soil and sand or the like scattered from the bucket 7 or the right and left outer sides, if not fine, the soil and sand will come into contact with the projecting distal end surface 13f of the projecting portion 13d or the right and left inner connecting surfaces 13g of the link main body portion 13a earlier than the grease supply pipe 22c, with the result that the grease supply pipe 22c can be effectively protected. In addition, since the grease supply pipe arrangement space 23 has a shape in which at least one of the side or the left and right inner sides opposite to the bucket 7 is opened, the manufacturing cost reduction of the idler link 13 is the same as the structure in which a hollow grease supply passage is formed inside the idler link, the structure of the idler link can be suppressed without being complicated, and the repair or replacement of the grease supply pipe 22c can also be easily performed. In the present embodiment, the left and right idler links are formed in a bilaterally symmetrical manner with the grease supply conduit arrangement space, and the grease supply conduit can be arranged at the power link even by either one of the left and right idler links. However, a configuration may be adopted in which the grease supply pipe arrangement space is provided only in one of the left and right idler links.

Further, in the present embodiment, the grease supply conduit arrangement space 23 has a shape cut obliquely from the projecting distal end surface 13f of the projecting portion 13d toward the left and right inner side connecting faces 13g of the link main body portion 13a, and the side opposite to the bucket 7 and the left and right inner sides are opened, but the grease supply conduit arrangement space 23 having such a shape can be easily formed, and the grease supply pipe 22c will be able to be arranged in a state where it does not project beyond the projecting distal end surface 13f of the projecting portion 13d in the direction opposite to the bucket 7 and does not project inward left and right beyond the left and right inner side connecting faces 13g of the link main body portion 13 a.

Further, the pipe fixing portions 23a for fixing the grease supply pipe 22c are provided at both end portions of the grease supply pipe arranging space 23 in the link length direction, and it is possible to prevent the accidental displacement of the grease supply pipe 22c arranged on the idle link 13.

Further, the grease supply pipe 22c disposed in the grease supply pipe disposition space 23 of the idler link 13 is coupled with the distribution valve 21 disposed on the arm-opposite-side link face 12c of the power link 12, and is configured to be able to supply grease from the distribution valve 21 to one end portion and the other end portion of the power link 12. Therefore, grease can be supplied to the shaft support portions 12a, 12b at both end portions of the power link 12 via the grease supply pipe 22c disposed on the idler link 13 and the distribution valve 21 provided on the power link. In this case, however, the distribution valve 21 is in a state of being protected by the arm 6 by being disposed on the arm-opposite-side link face 12c of the power link 12, so that the risk of breakage or failure of the distribution valve 21 can be significantly reduced.

Of course, the present invention is not limited to the above-described embodiment, and as the shape of the grease supply pipe arranging space, it is only necessary that the space is provided on the left and right inner sides of the left and right outer side faces of the protruding portion, and extends in the link length direction, and at least one of the side opposite to the work attachment or the left and right inner sides is open. For example, as shown in fig. 6A, the grease supply line arranging space 24 is cut in an L shape from the projecting distal end surface 13f of the projecting portion 13d toward the right and left inner connecting rod surfaces 13g of the connecting rod main body portion 13a, and is in a shape that is open on the side opposite to the working attachment and on the right and left inner sides; as shown in fig. 6B, the grease supply line arranging space 25 is formed in a groove shape in the protruding distal end face 13f of the recessed protruding portion 13d, and is open on the side opposite to the work attachment; as shown in fig. 6C, groove-like conduit-arranging spaces 26 recessed into the left and right inner side faces 13i of the protruding portion 13d and open on the left and right inner sides may also be used, but the formation of these shapes of conduit-arranging spaces 24, 25, 26 is simple, and even in any shape of grease-supplying conduit-arranging spaces 24, 25, 26, the grease-supplying conduit 22C will be able to be arranged in a state of not protruding beyond the protruding distal end face 13f of the protruding portion 13d in the direction opposite to the working attachment and not protruding inward left and right beyond the left and right inner connecting face 13g of the link main body portion 13 a.

Industrial applicability

The present invention can be used when arranging a grease supply pipe in a working machine such as a hydraulic excavator.