Work machine

Abstract

To provide a work machine with a configuration in which a boom bracket supporting a boom of the work machine is provided on a revolving frame through a revolving shaft, which allows whirl stop of the revolving shaft even in a simple configuration.SOLUTION: A excavation work machine 1 is provided with a boom bracket 42 revolvably supported on a revolving frame 7 through a revolving shaft 51a, a shaft direction of which is a vertical direction of a traveling body 2, and revolvably supporting an excavation device in the vertical direction through a revolving support shaft 48 placed higher than the revolving shaft 51a. The boom bracket 42 is provided with: a revolve stopping part 70 connected on an upper part of the revolving shaft 51a to limit revolving of the revolving shaft 51a for the boom bracket 42; and a pair of holding parts 75, 75 placed so as to clamp the revolving shaft 51a to hold the revolve stopping part 70.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a working machine equipped with a working device operated by hydraulic pressure.

Background Art

[0002] Conventionally, for example, a working machine such as an excavation working machine includes a lower traveling body having a pair of left and right crawler-type traveling units, an upper revolving body rotatably connected to the lower traveling body, and a working device provided on the front side of the revolving frame of the upper revolving body so as to be capable of pitching motion. The excavation working machine is also called a hydraulic excavator, and the working device is operated by hydraulic pressure.

[0003] The working device operated by hydraulic pressure has a plurality of hydraulic actuators that receive supply and discharge of pressure oil from a hydraulic source disposed within the upper revolving body. Each of these plurality of hydraulic actuators is connected to the hydraulic source by a plurality of hydraulic supply and discharge paths provided including metal pipes and hydraulic hoses having flexibility.

[0004] The working device of the excavation working machine is composed of a boom, an arm rotatably attached to the tip of the boom, and a working tool such as a bucket rotatably attached to the tip of the arm. The base end side of the boom is connected to a boom bracket provided on the front side of the revolving frame. Further, the boom bracket is horizontally rotatably connected to a support bracket provided to protrude forward from the revolving frame via a pair of upper and lower rotation shafts having the vertical direction as the axial direction. The hydraulic supply and discharge path for supplying and discharging pressure oil to the hydraulic actuators that respectively rotate the boom, the arm, and the bucket extends forward from the hydraulic source to the front of the revolving frame, passes through the boom bracket, and is constituted by a hydraulic hose extending to the back side of the boom.

[0005] In Patent Document 1, as a rotation prevention structure for the rotation axis (mounting pin) of the boom bracket, a substantially semi-circular slit is provided on the upper outer periphery of the upper rotation axis, and a lock plate is inserted into the slit to lock the upper mounting pin while the lock plate is fixed to the boom bracket. A configuration has been proposed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In Patent Document 1, the lock plate is arranged on the rear side of the upper mounting pin. In this case, in order to secure a space for fastening the fixing bolts around the mounting pin, it is necessary to increase the size of the boom bracket. Then, not only does the weight of the boom bracket increase, but also the length of the boom bracket in the front-rear direction increases, so that the position of the rotation axis is also at a position far from the driver's seat. For this reason, the turning radius of the excavation working machine increases, and the operability of the excavation working machine may be impaired.

[0008] The present invention has been made in view of the above problems, and in a configuration in which a boom bracket that supports the boom of a working device is disposed on a swing frame via a rotation axis, an object of the present invention is to provide a working machine that improves operability by realizing rotation prevention of the rotation axis with a simple and compact configuration.

Means for Solving the Problems

[0009] The working machine according to the present invention is rotatably supported by a swivel frame via a first shaft having the vertical direction of the machine body as the axial direction, and the working device is rotatably supported in the vertical direction via a second shaft disposed above the first shaft. The boom bracket is provided with a rotation restricting portion connected to the upper portion of the first shaft for restricting rotation of the first shaft with respect to the boom bracket, and a pair of holding portions disposed with the first shaft therebetween for holding the rotation restricting portion with respect to the boom bracket.

[0010] In the working machine according to another aspect of the present invention, in the working machine, the holding portion includes a holding portion main body portion and a fixing member for fixing the holding portion main body portion to the boom bracket.

[0011] In the working machine according to another aspect of the present invention, in the working machine, a hose guide is provided which is installed between the pair of holding portions and restricts contact of a hydraulic hose disposed between the first shaft and the second shaft with the rotation restricting portion and the pair of fixing members.

[0012] In the working machine according to another aspect of the present invention, in the working machine, the hose guide is arranged so as to face at least a part of the upper end of the first shaft.

[0013] In the working machine according to another aspect of the present invention, in the working machine, the holding portion main body portion has a holding plate portion for restricting upward movement of the first shaft with respect to the boom bracket by abutting against the rotation restricting portion, and a convex portion protruding from the lower surface of the holding plate portion for restricting rotation of the first shaft with respect to the boom bracket by abutting against the rotation restricting portion. The rotation restricting portion is provided with a receiving portion for receiving the convex portion, and the fixing member is a bolt inserted through a bolt insertion hole penetrating the holding plate portion and the convex portion.

[0014] In the working machine according to another aspect of the present invention, at the upper surface of the holding plate portion, an end portion of the hose guide is connected.

[0015] In the working machine according to another aspect of the present invention, in the working machine, the rotation prevention portion is formed of a plate body, and the receiving portion is a concave portion formed by being cut out inward from a side end surface of the plate body.

[0016] In the working machine according to another aspect of the present invention, in the working machine, a height of the convex portion is larger than a plate thickness of the rotation prevention portion.

[0017] In the working machine according to another aspect of the present invention, in the working machine, an upper portion of the first shaft is inseparably fitted into a fitting hole portion formed in the rotation prevention portion.

[0018] In the working machine according to another aspect of the present invention, in the working machine, a separation bolt hole for screwing a separation bolt when separating the first shaft from the boom bracket is formed in the rotation prevention portion.

Advantages of the Invention

[0019] In a configuration in which a boom bracket that supports a boom of a working device is disposed on a swing frame via a rotation shaft, it is possible to improve the operability of the working machine while realizing rotation prevention of the rotation shaft with a simple and compact configuration.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0021] In the present invention, in a configuration in which a boom bracket that supports a boom of a working device is disposed on a slewing frame via a rotation shaft, by devising a rotation prevention structure for the shaft provided at the upper part of the rotation shaft, while having a simple configuration, rotation prevention and pull-out prevention of the rotation shaft are realized. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0022] In an embodiment of the present invention, as a working machine according to the present invention, an excavation working machine (hydraulic excavator), which is a slewing working vehicle, will be described as an example. However, the working machine according to the present invention is not limited to an excavation working machine, and can be widely applied to other working machines such as a crane working machine.

[0023] The overall configuration of the excavation work machine 1 according to the present embodiment will be described with reference to FIG. 1. Hereinafter, unless otherwise specified, based on the position of the operator seated in the driver's seat of the excavation work machine 1, it is referred to as the "front side", "rear side", "left and right sides", "plane side" or "upper side", "bottom side" or "lower side".

[0024] As shown in Fig. 1, the excavation work machine 1 includes a traveling vehicle body 2 which is a self - propelled machine body, an excavation device 3 and an earth - discharging device 4 as working devices attached to the traveling vehicle body 2. The traveling vehicle body 2 is composed of a lower traveling body 20A provided with traveling parts 5 and an upper slewing body 20B rotatably provided above the lower traveling body 20A. The earth - discharging device 4 is attached to the lower traveling body 20A side, and the excavation device 3 is attached to the upper slewing body 20B side.

[0025] The lower traveling body 20A has a pair of left - and - right crawler - type traveling parts 5, 5 and a track frame 6 as a base interposed between the left - and - right traveling parts 5, 5.

[0026] The traveling part 5 has a configuration in which a crawler is wound around a sprocket, an idler, and a plurality of rollers supported by the track frame 6. The traveling part 5 has a drive sprocket 5a which is a drive wheel at its rear end.

[0027] The track frame 6 has a center frame part 6a located between the left - and - right traveling parts 5, 5 and side frame parts 6b provided on both left and right sides of the center frame part 6a.

[0028] The earth - discharging device 4 is attached to the front side of the track frame 6. The earth - discharging device 4 has a pair of support frames 4b extending in the front - rear direction between the left - and - right traveling parts 5, 5 and a blade 4a as an earth - discharging plate provided at the tip side of the support frame 4b. The earth - discharging device 4 is provided so as to be able to move up and down and rotate by a blade cylinder (not shown) provided between the support frame 4b and the track frame 6. The earth - discharging device 4 including these configurations is configured to be substantially left - right symmetric as a whole.

[0029] The slewing frame 7 is configured in a substantially circular shape in plan view, and is provided on the upper side of the track frame 6 with a slewing bearing 6c provided on the track frame 6 so as to be slewed in either the left or right direction around a vertical axis. A counterweight 7a is provided at the rear lower part of the slewing frame 7. Further, the slewing frame 7 is configured to be slewed within the left and right widths of the left and right traveling units 5, 5, that is, within the width between the left outer edge of the left traveling unit 5 and the right outer edge of the right traveling unit 5. This enables small-slewing operations by the excavation work machine 1.

[0030] A box-shaped cabin 10 is provided on the slewing frame 7. A tank section 9 is provided on the right side of the cabin 10 (see Fig. 2). The tank section 9 is provided with a hydraulic oil tank for storing the hydraulic oil supplied to hydraulic actuators such as the hydraulic cylinders of the excavation work machine 1. Further, an engine 12, which is a prime mover, is provided as a drive source at the rear part of the slewing frame 7. The rear part and the right side surface of the slewing frame 7 are covered by a bonnet and an exterior cover.

[0031] The cabin 10 is provided with a driver's seat on which the operator sits, and an operating device for operating and controlling the excavation device 3 and the traveling units 5. The operating device includes an operation panel section having various operation parts such as a work operation lever and switches for operating the working parts such as the excavation device 3, and they are arranged around the driver's seat. Further, a door 16 serving as an entrance and exit for the operator is provided on the left side surface of the cabin 10.

[0032] The excavation device 3 is a working device that operates hydraulically, and is a front working device provided on the front side of the excavation work machine 1. At approximately the center of the left and right sides at the front end of the slewing frame 7, a support bracket 41 for supporting the excavation device 3 projects forward. The boom bracket 42 forming the base end of the excavation device 3 is rotatably supported on the support bracket 41 with the vertical direction as the rotation axis direction. The excavation device 3 is provided so as to rotate left and right (in the horizontal direction) with respect to the slewing frame 7 by a swing cylinder 29 (see Fig. 2) provided between the boom bracket 42 and the slewing frame 7.

[0033] The excavating device 3 has a boom 21 having a shape bent like a boomerang in side view and constituting a base side portion of the excavating device 3, an arm 22 connected to the tip side of the boom 21, and a bucket 23 attached to the tip of the arm 22. The excavating device 3 has a boom cylinder 26 that rotates the boom 21, an arm cylinder 27 that rotates the arm 22, and a working tool cylinder 28 that rotates the bucket 23. All of these cylinders are hydraulic cylinders. In the excavating device 3, other devices such as a grapple or a breaker are attached in place of the bucket 23 according to the work content.

[0034] In the excavating work machine 1 having the above configuration, when the operator appropriately operates the operating device in the cabin 10, a desired operation / work is performed.

[0035] The configuration of the support portion of the excavating device 3 provided at the front end of the slewing frame 7 will be described with reference to FIGS. 2 to 6. FIG. 2 is a partial cross-sectional view showing an enlarged view of the support portion of the excavating device 3 at the front end of the slewing frame 7 indicated by reference numeral D in FIG. 1. FIG. 3 is an exploded perspective view showing the main members of the mounting structure of the anti-rotation portion 70 with respect to the rotation shaft 51a in the boom bracket 42. FIGS. 4 and 5 are perspective views from the rear upper left showing an enlarged view of the attachment portion of the anti-rotation portion 70 in the boom bracket 42. FIG. 4 shows the state before attaching the anti-rotation portion 70 and the rotation shaft 51a, and FIG. 5 shows the state after attaching the anti-rotation portion 70. Further, FIG. 6 is a side view in a state where the anti-rotation portion 70 is attached, and shows a partial cross-section of the boss portion 45a of the boom bracket 42. In FIGS. 2 and 4, the illustration of the cabin 10 is omitted.

[0036] The support bracket 41 is constituted by a pair of upper and lower connecting parts 41a and 41b that project horizontally at a predetermined distance in front of the bottom plate 7b of the swivel frame 7. At positions on the same vertical line of the pair of upper and lower connecting parts 41a and 41b, holes through which the rotation shafts 51a and 51b as the first shafts can be inserted are respectively provided. A bush 41c with a flange is provided in the hole of the connecting part 41a, and a bush 41d with a flange is provided in the hole of the connecting part 41b. The bushes 41c and 41d with flanges have a cylindrical bush part and an annular flange part that projects radially outward from one end of the bush part. The inner diameters of the cylindrical bush parts of the bushes 41c and 41d with flanges are formed slightly larger than the diameters of the rotation shafts 51a and 51b so as to allow the rotation of the rotation shafts 51a and 51b inside. The bush 41c with a flange and the bush 41d with a flange are provided symmetrically up and down with respect to each other such that the flange parts face the insertion direction side of the rotation shafts 51a and 51b.

[0037] Also, in the support bracket 41, an opening 39 (see FIG. 2) communicating with the inside of the swivel frame 7 is provided between the pair of upper and lower connecting parts 41a and 41b. This opening 39 enables the insertion of a hydraulic hose 55 extending from a hydraulic source.

[0038] The boom bracket 42 is formed by die casting and has a pair of left and right wall parts 43a and 43b. Between the pair of left and right wall parts 43a and 43b of the boom bracket 42, a rotation support shaft 48 as the second shaft for rotatably supporting the boom 21 and a rotation support shaft 49 for rotatably supporting the boom cylinder 26 are installed. The rotation support shaft 48 and the rotation support shaft 49 are arranged parallel to each other with the substantially horizontal direction as the axial direction. Further, on the right wall part 43b of the boom bracket 42, a swing cylinder connecting part 33 (see FIG. 4) is provided to project horizontally from the side.

[0039] On the upper and lower sides of the rear surface of the boom bracket 42, connecting portions 45 and 46 are provided which are connected to the upper and lower pair of connecting portions 41a and 41b of the support bracket 41 via rotation shafts 51a and 51b respectively. The connecting portions 45 and 46 are provided below the rotation support shaft 48 and behind the rotation support shaft 49. Note that the rotation shafts 51a and 51b have a hollow cylindrical shape inside.

[0040] The upper connecting portion 45 of the boom bracket 42 has a pair of upper and lower boss portions 45a and 45b formed so as to form a substantially horizontal U-shaped with the front wall portion in side view and the rear side being the open side. Similarly, the lower connecting portion 46 of the boom bracket 42 has a pair of upper and lower boss portions 46a and 46b formed so as to form a substantially horizontal U-shaped with the front wall portion in side view and the rear side being the open side.

[0041] At positions on the same vertical line of each of the boss portions 45a, 45b, 46a, and 46b, hole portions through which the rotation shafts 51a and 51b can be inserted are provided. A cylindrical bush 45d is press-fitted into the hole portion of the boss portion 45a, and a cylindrical bush 45e is press-fitted into the hole portion of the boss portion 45b. Similarly, a cylindrical bush 46d is press-fitted into the hole portion of the boss portion 46a, and a cylindrical bush 46e is press-fitted into the hole portion of the boss portion 46b.

[0042] In the lower boss portion 46b of the connecting portion 46, a hole portion 54 (see FIG. 2) into which a bolt 53 can be inserted is provided with the direction perpendicular to the rotation axis direction (left-right direction) as the penetration direction. By passing the bolt 53 through the lower boss portion 46b and the lower rotation shaft 51b in the radial direction and fastening it with a nut 52, the lower rotation shaft 51b is fixed to the connecting portion 46.

[0043] Arrange the connecting part 45 of the boom bracket 42 and the connecting part 41a of the support bracket 41 on the same vertical line, insert the rotating shaft 51a into the shaft hole part 58a, arrange the connecting part 46 of the boom bracket 42 and the connecting part 41b of the support bracket 41 on the same vertical line, and insert the rotating shaft 51b into the shaft hole part 58b. Thus, the rotating shaft 51a and the rotating shaft 51b are coaxially arranged with each other with the axial direction being the vertical direction. In the above configuration, the boom bracket 42 is connected and supported to the support bracket 41 so as to rotate left and right with the rotation axis line C1 (see Fig. 2) along the vertical direction that coincides with the central axis of the rotating shaft 51a and the rotating shaft 51b as the rotation center.

[0044] Next, the members related to the rotation prevention of the rotating shaft 51a with respect to the boom bracket 42 will be further described.

[0045] On the horizontal upper end surface 45c of the upper connecting part 45 of the boom bracket 42, a rotation prevention part 70 is arranged. The rotation prevention part 70 is a member for preventing the upper rotating shaft 51a from rotating differently from the movement of the boom bracket 42 when the boom bracket 42 rotates in the left - right direction. That is, the rotation prevention part 70 is a part for restricting the relative rotation of the rotating shaft 51a with respect to the boom bracket 42 in the rotation of the boom bracket 42 around the axis of the rotating shaft 51a along the vertical direction, and for rotating the rotating shaft 51a substantially integrally with the boom bracket 42.

[0046] The rotation prevention part 70 is formed from a steel plate with a predetermined thickness, and a fitting hole part 71 into which the upper part of the rotating shaft 51a fits is formed at the center of the rotation prevention part 70. The upper rotating shaft 51a is fixed to the fitting hole part 71 by welding. That is, the rotation prevention part 70 is a part provided in a flange - like manner integrally with the upper end part of the upper rotating shaft 51a.

[0047] By fixing the plate-like member (plate body) forming the rotation stopper portion 70 to the upper end portion of the rotation shaft 51a by welding, an integral shaft member 80 is configured in which the rotation stopper portion 70 is a flange portion protruding radially outward over the entire circumferential direction of the rotation shaft 51a (see FIG. 3). In the shaft member 80, the upper end portion of the rotation shaft 51a protrudes from the upper surface 70a of the rotation stopper portion 70 and forms the upper opening end portion in the cylindrical outer shape of the rotation shaft 51a. The rotation shaft 51a has an opening end surface along a plane perpendicular to the rotation axis line C1.

[0048] The rotation shaft 51a is originally rotatable with respect to the boom bracket 42 within a slight rotation range restricted by the rotation stopper portion 70. However, due to long-term use of the excavation work machine 1 or the like, the rotation shaft 51a may become fixed to the boom bracket 42. In such a case, the rotation shaft 51a is separated from the boom bracket 42. Therefore, female screw holes 72 as separation bolt holes for screwing separation bolts (not shown) are formed at two locations on the left and right sides of the rear portion of the rotation stopper portion 70. By screwing separation bolts into these female screw holes 72 and further screwing in the separation bolts that penetrate the rotation stopper portion 70 and abut against the upper end surface 45c, as the protruding amount of the separation bolts downward from the rotation stopper portion 70 increases, the rotation stopper portion 70 rises from the upper end surface 45c of the connecting portion 45. As a result, the rotation shaft 51a disposed through the boss portion 45a of the boom bracket 42 and the connecting portion 41a of the support bracket 41 can be separated from the boom bracket 42 (more specifically, the upper end surface 45c of the connecting portion 45), and the two can be easily separated. The formation position of the female screw holes 72 is not particularly limited, but is formed on the side closer to the rear end of the boss portion 45a of the boom bracket 42 for the convenience of the pulling-out operation of the upper rotation shaft 51a. In other words, the female screw holes 72 are provided in the boom bracket 42 at a position far from the rear of the rotation support shaft 48 (second shaft) that supports the boom 21.

[0049] Further, concave notches 73, 73 are provided at the left and right end portions of the rotation prevention portion 70. The concave notches 73, 73 are concave portions that are notched in a substantially U shape in a plan view from the respective left and right end faces of the rotation prevention portion 70 toward the center, and are formed in pairs at symmetrical positions with the fitting hole portion 71 interposed therebetween. Note that the outer shape of the rotation prevention portion 70 is changed according to the area of the upper end face 45c of the connecting portion 45 and the arrangement of other members (for example, the hydraulic hose holding device 60). That is, the outer shape of the rotation prevention portion 70 does not necessarily have to be symmetric with respect to the front-rear and / or left-right directions as long as it can form the fitting hole portion 71 that can non-rotatably fit the upper portion of the rotation shaft 51a and the pair of concave notches 73, 73.

[0050] The rotation prevention portion 70 is held by a pair of holding portions 75, 75. The holding portion 75 is composed of a holding portion main body portion 74 including a holding plate portion 76 and a convex portion 77, and a pair of bolts 78, 78 as fixing members for the boom bracket 42. The holding plate portion 76 has a substantially square shape and is disposed above the rotation prevention portion 70. An end portion of the hose guide 79 is connected to the upper surface 76a of the holding plate portion 76 by welding or the like.

[0051] The hose guide 79 is formed by bending a round bar or the like in an inverted U shape. The hose guide 79 includes a horizontal portion 79a disposed substantially parallel to the rotation prevention portion 70, and a pair of leg portions 79b, 79b that support the horizontal portion 79a at a predetermined height. In the hose guide 79, the length of the leg portion 79b is adjusted so that the horizontal portion 79a is positioned higher than the head portion 78a of the bolt 78 as a fixing member for attaching the holding portion 75 to the boom bracket 42. In the hose guide 79, the length of the horizontal portion 79a is equal to or slightly longer than the arrangement width of a plurality of hydraulic hoses 55 arranged in a row in the left-right direction within the boom bracket 42. Further, as shown in FIG. 6, the hose guide 79 is arranged such that the horizontal portion 79a faces the upper end of the rotation shaft 51a and is displaced forward from the center (rotation axis C1) of the rotation shaft 51a in the front-rear direction. Thereby, a space for the operator to perform the fastening work of the bolt 78 is secured behind and above the rotation shaft 51a.

[0052] On the lower surface 76b side of the holding plate portion 76, a convex portion 77 is fixed by welding or the like. The convex portion 77 is formed from a collar-like member having a cylindrical shape. As a result, a bolt insertion hole 75a through which a bolt 78 is inserted through the holding plate portion 76 and the convex portion 77 is formed. The lower end of the convex portion 77 abuts against a countersunk portion 47 formed on the upper end surface 45c of the connecting portion 45 of the boom bracket 42. A female screw hole 59 for screwing the bolt 78 is provided at the center of the countersunk portion 47. Note that the diameter of the countersunk portion 47 is made equal to the width in the front-rear direction of the concave notch portion 73.

[0053] In this way, the left and right holding portions 75 and the hose guide 79 connecting these to each other constitute an integral mounting member 81 for the boom bracket 42. The mounting member 81 is fixed to the boom bracket 42 in such a manner that the rotation prevention portion 70 is sandwiched vertically between the boss portion 45a and the holding plate portion 76 by bolts 78 passing through the left and right holding portions 75.

[0054] When an operator attaches the boom bracket 42 to the support bracket 41, the connecting portion 41a on the support bracket 41 side is sandwiched between the boss portions 45a and 45b of the connecting portion 45, and the connecting portion 41b on the support bracket 41 side is sandwiched between the boss portions 46a and 46b of the connecting portion 46, so that the boom bracket 42 is engaged with the support bracket 41. As a result, a shaft hole portion 58a penetrating through the connecting portion 45 of the boom bracket 42 and the connecting portion 41a of the support bracket 41 is formed. Similarly, a shaft hole portion 58b penetrating through the connecting portion 46 of the boom bracket 42 and the connecting portion 41b of the support bracket 41 is formed.

[0055] For the shaft hole portion 58b formed by the hole portions of the boss portions 46a and 46b on the lower side of the boom bracket 42 and the hole portion of the connecting portion 41b on the lower side of the support bracket 41, the rotation shaft 51b is inserted from below. In a state where the rotation shaft 51b is inserted into the shaft hole portion 58b, a cylindrical bush 46e is interposed between the hole portion of the boss portion 46b and the rotation shaft 51b, and a cylindrical portion of the flanged bush 41d is interposed between the hole portion of the connecting portion 41b and the rotation shaft 51b, and a cylindrical bush 46e is interposed between the hole portion of the boss portion 46a and the rotation shaft 51b. Thereafter, a bolt 53 is inserted into the hole portion 54 of the boss portion 46b in the connecting portion 46 of the boom bracket 42 to penetrate the rotation shaft 51b in the radial direction, and a nut 52 (see FIG. 4) is fastened to the end portion of the bolt 53 protruding from the boss portion 46b, whereby the rotation shaft 51b is fixed to the boom bracket 42.

[0056] Also, for the shaft hole portion 58a formed by the hole portions of the boss portions 45a and 45b on the upper side of the boom bracket 42 and the hole portion of the connecting portion 41a on the upper side of the support bracket 41, the rotation shaft 51a is inserted from above. In a state where the rotation shaft 51a is inserted into the shaft hole portion 58a, a cylindrical bush 45d is interposed between the hole portion of the boss portion 45a and the rotation shaft 51a, and a cylindrical portion of the flanged bush 41c is interposed between the hole portion of the connecting portion 41a and the rotation shaft 51a, and a cylindrical bush 45e is interposed between the hole portion of the boss portion 45b and the rotation shaft 51a. Since the rotation shaft 51a is integrated with the rotation prevention portion 70 as a shaft member 80, when the rotation shaft 51a is inserted into the shaft hole portion 58a from above, the rotation prevention portion 70 engages with the connecting portion 45 in a state of being placed on the upper end surface 45c.

[0057] Next, as shown by the two-dot chain line in FIG. 3, a convex portion 77 is positioned in each of the pair of concave recesses 73, 73 of the rotation prevention portion 70, and then a bolt 78 is inserted into the bolt insertion hole 75a. By screwing the bolt 78 into the female screw hole 59 opened facing the upper end surface 45c of the connecting portion 45, the holding portion main body portion 74 is attached to the boom bracket 42. That is, the rotation prevention portion 70 is held by the boom bracket 42 via the pair of holding portions 75, 75 (see FIG. 5).

[0058] When the boom bracket 42 rotates, it is necessary to prevent the rotation of the rotation shaft 51a around the boom bracket 42 and the upward disengagement while allowing the movement of the rotation shaft 51a within a certain range. In the present embodiment, by providing the rotation prevention portion 70 above the rotation shaft 51a, the rotation of the rotation shaft 51a with respect to the boom bracket 42 is restricted, and by providing the holding portion 75, the upward disengagement of the rotation shaft 51a with respect to the boom bracket 42 through the rotation prevention portion 70 is prevented.

[0059] The inner circumference of the concave portion of the concave notch portion 73 of the rotation prevention portion 70 is formed with a slight clearance larger than the cylindrical outer circumference of the convex portion 77 (see FIG. 6). The movement in the rotational direction around the axis of the rotation shaft 51a greater than the clearance provided between the inner circumference of the concave notch portion 73 of the rotation prevention portion 70 and the outer circumference of the convex portion 77 is restricted by the contact of the outer circumference of the convex portion 77 with the inner circumference of the concave notch portion 73. That is, the rotation prevention portion 70 restricts the movement of the rotation shaft 51a in the rotational direction and functions as a rotation prevention for the boom bracket 42.

[0060] In this way, the rotation shaft 51a is provided so as to be slightly rotatable by the amount of play with respect to the convex portion 77 in the concave notch portion 73 of the rotation prevention portion 70 about the rotation axis C1 with respect to the boom bracket 42, and rotates integrally with the boom bracket 42 about the rotation axis C1 in a state where the relative rotation with respect to the boom bracket 42 is restricted by the convex portion 77. Specifically, when the boom bracket 42 rotates to the left about the rotation axis C1, the rotation prevention portion 70 causes the inner circumferential surface of the left concave notch portion 73 to contact the convex portion 77 from the front side, and the inner circumferential surface of the right concave notch portion 73 to contact the convex portion 77 from the rear side. When the boom bracket 42 rotates to the right about the rotation axis C1, the contact mode of the inner circumferential surface of the concave notch portion 73 with respect to the left and right convex portions 77 is reversed front and back from the case of rotating to the left.

[0061] Further, the height of the convex portion 77 is set higher than the plate thickness of the rotation prevention portion 70 formed of a plate body so that a gap L (see FIG. 6) is formed between the upper surface 70a of the rotation prevention portion 70 and the lower surface 76b of the holding plate portion 76. The vertical movement of the rotation prevention portion 70 greater than or equal to the gap L is restricted by the holding plate portion 76. The upward movement of the rotation prevention portion 70 is restricted by the upper surface 70a of the rotation prevention portion 70 coming into contact with the lower surface 76b of the holding plate portion 76. The downward movement of the rotation prevention portion 70 is restricted by the lower surface 70b of the rotation prevention portion 70 coming into contact with the upper end surface 45c of the boom bracket 42. That is, the holding plate portion 76 of the holding portion 75 prevents the rotation shaft 51a from coming out upward. That is, the rotation prevention portion 70 functions as a retaining means for the rotation shaft 51a with respect to the boom bracket 42.

[0062] In this way, with respect to the upward movement of the rotation shaft 51a with respect to the boom bracket 42, the gap L with respect to the holding plate portion 76 in a state where the rotation prevention portion 70 contacts the upper end surface 45c of the boom bracket 42 with its lower surface 76b becomes play, and the rotation shaft 51a is provided to be slightly movable upward by the amount of this play. The dimension of the gap L is, for example, about several millimeters.

[0063] Inside the boom bracket 42, a hydraulic hose 55 made of a movable member is disposed. A plurality of hydraulic hoses 55 extending forward from inside the slewing frame 7 through the opening 39 are drawn forward of the boom bracket 42 through an opening 57 formed between the upper connecting portion 45 and the lower connecting portion 46 on the upper side of the boom bracket 42 as shown in FIG. 2. Further, the hydraulic hose 55 is routed in a manner that it goes upward in the space 56 between the left and right wall portions 43a and 43b and then turns back rearward, is guided obliquely upward from the front to the rear by the hydraulic hose holding device 60, passes below the rotation support shaft 48 and above the rotation shaft 51a, and reaches the back side of the boom 21 of the excavating device 3. In such a piping path of the hydraulic hose 55, above the rotation shaft 51a, there is formed a space portion surrounded by the boss portion 45a, the left and right wall portions 43a and 43b, and the rotation support shaft 48, and a hydraulic hose arrangement space through which the hydraulic hose 55 penetrates in the front-rear direction in plan view is formed.

[0064] Each of the plurality of hydraulic hoses 55 is held in a fixed state at each of a hydraulic hose holding device 60 and a holding member (not shown) fixed to the back surface of the boom 21, and the shape is changed depending on the posture of the excavating device 3 (the rotation position of the boom 21) between the hydraulic hose holding device 60 and the holding member (not shown) on the back surface of the boom 21. More specifically, the portion of the plurality of hydraulic hoses 55 extending rearward from the hydraulic hose holding device 60 until reaching the back surface of the boom 21 forms a curved shape that bulges rearward in a side view when the boom 21 is in the upright posture (see FIGS. 1 and 2), and the shape is changed so that the bulge to the rear gradually decreases as the boom 21 falls forward.

[0065] When the hydraulic hose 55 deforms according to the operation of the boom 21, the hydraulic hose 55 passing above the rotation shaft 51a may be damaged by contacting and rubbing against the edge portion of the rotation prevention portion 70 or the edge portion of the head 78a of the bolt 78.

[0066] In the present embodiment, a hose guide 79 having a horizontal portion 79a whose longitudinal direction is the left-right direction is installed between a pair of holding portions 75 that hold the rotation prevention portion 70. Thereby, it is possible to prevent the movable hydraulic hose 55 from touching the edge portion of the rotation prevention portion 70 or the edge portion of the head 78a of the bolt 78. Since the hose guide 79 is formed of a round bar without an edge, the hydraulic hose 55 that comes into contact with the hose guide 79 is not damaged either.

[0067] Further, in the present embodiment, by integrally providing the hose guide 79 on the pair of holding portions 75 that hold the rotation prevention portion 70, the holding of the rotation prevention portion 70 with respect to the boom bracket 42 and the attachment of the hose guide 79 can be simultaneously performed by the operation of fastening the pair of bolts 78. Further, when the operator handles the attachment member 81 in an operation such as attaching and detaching the holding portion 75, the hose guide 79 can be used as a handle. Therefore, the assembly work of the excavating work machine 1 can be made more efficient.

[0068] Next, regarding a modification example of the hose guide, FIG. 7 is a longitudinal sectional view showing the periphery of the hose guide 79 according to the modification example. In FIG. 7, the hose guides 89, 99 according to other modification examples and the extended portions of the holding plate portion 76 are shown by long dashed lines.

[0069] As shown in FIG. 7, the hose guide 79 according to this modification example is obtained by arranging the hose guide 79 and the holding portion 75 shown in FIGS. 5 and 6 in a reversed front-back manner. That is, the hose guide 79 is disposed at a position facing the rotation shaft 51a and is offset rearward in the front-back direction. For example, if a working space can be secured in front of the boom bracket 42, such as in a state where the hydraulic hose holding device 60 and the hydraulic hose 55 are not attached, the fastening position of the bolt 78 may be set on the front side of the hose guide 79.

[0070] Also, the shape, position, and number of the hose guides can be changed. The hose guide 89 shown by the long dashed line in FIG. 7 has a shape that is bent rearward in a side view. If the hose guide does not interfere with the fastening and pulling-out operations of the bolt 78, it may be arranged to face a position closer to the center of the rotation shaft 51a, like the hose guide 89.

[0071] Also, the holding plate portion 76 of the holding portion 75 may be extended in the front-back direction to provide both the hose guide 79 and the hose guide 89. Also, if the hose guide can maintain a height at which the hydraulic hose 55 does not contact the rotation shaft 51a, the detent portion 70, and the head 78a of the bolt 78, it does not necessarily have to face the rotation shaft 51a, like the hose guide 99 shown by the long dashed line in FIG. 7.

[0072] Furthermore, when a plurality of hose guides are provided on the holding portion 75, two hose guides 79 of the same shape may be provided, or hose guides 89 with different shapes and hose guides 99 with different heights may be arranged in combination. In this case, as shown by the long dashed lines extended from the front and back of the holding plate portion 76 in FIG. 7, the length of the holding plate portion 76 in the front-back direction is appropriately changed.

[0073] In addition, in the present embodiment, the receiving portion for receiving the convex portion 77 is formed as the concave portion 73, but it is not limited to this. The receiving portion may be a hole portion such as a circle or an ellipse in a plan view that penetrates the rotation prevention portion 70 and allows the convex portion 77 to be loosely inserted. Note that making the receiving portion of the convex portion 77 the concave portion 73 can reduce the weight of the rotation prevention portion 70 more than making it a hole portion.

[0074] It can be said that the excavation work machine 1 according to the present embodiment as described above has the following configuration. That is, the excavation work machine 1 includes a boom bracket 42 that is rotatably supported on a swing frame 7 via a first shaft (rotation shaft 51a) having the vertical direction of the machine body as the axial direction, and the work device (excavation device 3) is rotatably supported in the vertical direction via a second shaft (rotation support shaft 48) disposed above the first shaft (rotation shaft 51a). The boom bracket 42 is provided with a rotation prevention portion 70 connected to the upper portion of the first shaft (rotation shaft 51a) for restricting the rotation of the first shaft (rotation shaft 51a) with respect to the boom bracket 42, and a pair of holding portions 75, 75 that are disposed with the first shaft (rotation shaft 51a) interposed therebetween and hold the rotation prevention portion 70 with respect to the boom bracket 42.

[0075] According to such an excavation work machine 1, in the configuration in which the boom bracket 42 that supports the work device is disposed on the swing frame 7 via the rotation shaft 51a, the boom bracket 42 is provided with a rotation prevention portion 70 connected to the upper portion of the first shaft (rotation shaft 51a), and a pair of holding portions 75, 75 that are disposed with the first shaft (rotation shaft 51a) interposed therebetween and hold the rotation prevention portion 70. Thus, it is possible to prevent rotation and prevent disengagement of the rotation shaft 51a with a simple configuration without increasing the size of the boom bracket 42. In particular, since the space for the portion behind the rotation shaft 51a in the boom bracket 42 can be reduced, the rotation shaft 51a can be brought closer to the traveling vehicle body 2 accordingly, so that the turning radius of the excavation work machine 1 can be reduced. Thereby, the operability of the excavation work machine 1 can be improved.

[0076] In addition, in the excavation work machine 1, the holding parts 75, 75 include a holding part main body 74 and fixing members (bolts 78, 78) for fixing the holding part main body 74 to the boom bracket 42.

[0077] According to such an excavation work machine 1, by fastening the pair of holding parts 75, 75 to the boom bracket 42 with bolts 78 respectively, it is possible to attach and detach the first shaft (rotating shaft 51a), and it is possible to improve the workability of maintenance. Note that the fixing member for fixing the holding part 75 to the boom bracket 42 is not limited to the bolt 78, and may be other shaft-like members such as pins. Further, as a configuration for fixing the holding part 75 to the boom bracket 42, for example, a male screw part may protrude upward from the upper end surface 45c of the connecting part 45, and a fastening structure in which a nut is screwed onto the male screw part penetrating the holding part 75 may be used.

[0078] In addition, in the excavation work machine 1, there is provided a hose guide (79, 89, 99) that is installed between the pair of holding parts 75, 75 and restricts the hydraulic hose 55 disposed between the first shaft (rotating shaft 51a) and the second shaft (rotating support shaft 48) from contacting the rotation prevention part 70 and the pair of fixing members (heads 78a of the bolts 78, 78).

[0079] In a conventional excavation work machine as shown in Patent Document 1, there has been a problem that a hydraulic hose that bends as the boom rotates rubs against an edge portion of a lock plate arranged for preventing rotation with respect to the boom bracket or a head portion of a bolt for fixing the lock plate and is damaged.

[0080] According to the excavation work machine 1 according to the present embodiment, by providing the hose guides (79, 89, 99), it is possible to prevent the hydraulic hose 55 from coming into contact with and rubbing against the edge portions such as the rotation prevention portion 70 and the heads 78a of the pair of bolts 78, 78 and being damaged. Note that the hose guide is not limited to a configuration in which a round bar-shaped member is bent. For example, a curved plate-shaped member such as a semi-cylindrical plate-shaped member may be provided so as to cover the left and right bolts 78 from above. However, according to the configuration in which the hose guide is formed by a round bar-shaped member as in the present embodiment, a hose guide having a curved surface portion with the hydraulic hose 55 side as the convex side can be provided as a contact portion with respect to the hydraulic hose 55 easily and at low cost.

[0081] In the excavation work machine 1, the hose guides (79, 89, 99) are arranged so as to face at least the upper end of the first axis (rotation axis 51a). That is, the hose guides (79, 89, 99) are provided so as to overlap at least a part of the rotation axis 51a in plan view.

[0082] According to such an excavation work machine 1, by providing the hose guides (79, 89, 99) at positions facing the upper end of the first axis (rotation axis 51a), it is possible to effectively prevent the hydraulic hose 55 from coming into contact with and rubbing against the edge portions such as the rotation prevention portion 70 and the heads 78a of the pair of bolts 78, 78, or the edge portion of the upper end protruding portion of the rotation axis 51a and being damaged.

[0083] In the excavation work machine 1, the holding portion main body portion 74 includes a holding plate portion 76 that abuts against the rotation prevention portion 70 to restrict the upward movement of the first axis (rotation axis 51a) with respect to the boom bracket 42, and a convex portion 77 that protrudes from the lower surface of the holding plate portion 76 and abuts against the rotation prevention portion 70 to restrict the rotation of the first axis (rotation axis 51a) with respect to the boom bracket 42. The rotation prevention portion 70 is provided with a receiving portion (concave portion 73) for receiving the convex portion 77, and the fixing member is a bolt 78 that is inserted through a bolt insertion hole 75a that penetrates the holding plate portion 76 and the convex portion 77.

[0084] According to such an excavation working machine 1, since the pair of holding parts 75, 75 can make the holding plate part 76 contact with the upper surface 70a of the rotation prevention part 70 and the convex part 77 contact with the inner side surface of the receiving part (concave notch part 73), at least the movements of the rotation prevention part 70 connected to the first shaft (rotation shaft 51a) in the vertical direction and the front-rear direction can be restricted. Thereby, it becomes possible to more reliably prevent the first shaft (rotation shaft 51a) from rotating and coming off.

[0085] In the excavation working machine 1, the end parts of the hose guides (79, 89, 99) are connected to the upper surface 76a of the holding plate part 76.

[0086] According to such an excavation working machine 1, by integrally providing the pair of holding parts 75, 75 and the hose guides (79, 89, 99) as attachment members 81 to the boom bracket 42, it becomes possible to more easily install the holding parts 75, 75 and the hose guides (79, 89, 99). Thereby, the efficiency of the assembly work of the excavation working machine 1 is improved. In particular, in the present embodiment, the attachment member 81 is fixed to the boom bracket 42 by bolts 78. According to such a configuration, after performing the installation work of the rotation shaft 51a with respect to the boom bracket 42 accompanied by hitting the rotation shaft 51a with a hammer or the like, by attaching the attachment member 81, the pair of holding parts 75, 75 and the hose guides (79, 89, 99) can be provided. Thereby, in the installation work of the rotation shaft 51a, the hose guides (79, 89, 99) and the like do not get in the way, and the rotation shaft 51a can be easily installed. Further, after the installation of the rotation shaft 51a, even when hitting the upper part of the rotation shaft 51a with a hammer or the like for the purpose of releasing the fixation of the rotation shaft 51a to the swing frame 7 side (support bracket 41 side) of the rotation shaft 51a, by devising such as arranging the hose guides (79, 89, 99) at positions shifted in the front-rear direction from the axis of the rotation shaft 51a, such work is not hindered.

[0087] In the excavation working machine 1, the rotation prevention part 70 is formed of a plate body, and the receiving parts are concave notch parts 73, 73 formed by cutting notches inward from the side end surfaces of the plate body.

[0088] According to such an excavation working machine 1, by forming the receiving portion of the convex portion 77 of the holding portion 75 as the concave recessed portions 73, 73, the convex portion 77 can be brought closer to the rotation shaft 51a side, and the width of the plate body of the rotation preventing portion 70 does not need to be increased, and the rotation preventing portion 70 can be made lighter and more compact. As a result, the connection portion 45 of the boom bracket 42 forming the installation surface of the rotation preventing portion 70 can be made more compact.

[0089] Further, in the excavation working machine 1, the height of the convex portion 77 of the holding portion 75 is greater than the thickness of the plate body of the rotation preventing portion 70.

[0090] According to such an excavation working machine 1, by making the height of the convex portion 77 greater than the plate thickness of the rotation preventing portion 70, a pair of holding portions 75, 75 can provide a clearance that allows the rotation preventing portion 70 to move up and down therebetween. Therefore, it is possible to avoid the phenomenon that the outer periphery of the first shaft (rotation shaft 51a) and the inner peripheral surface of the shaft hole portion 58a of the boom bracket 42 are in close contact and the first shaft (rotation shaft 51a) does not come off during maintenance.

[0091] Further, the rotation preventing portion 70 is configured to have a play (a slight clearance) with respect to a pair of holding portions 75 in the vertical direction and with respect to the convex portion 77 in the rotation direction of the rotation shaft 51a. According to such a configuration, for example, compared with a configuration in which there is no play between the rotation preventing portion 70 and each of the holding portion 75 and the convex portion 77, the stress acting on the rotation preventing portion 70 from the boom bracket 42 during the operation of the excavation device 3 or the like can be reduced. As a result, deformation and deterioration over time of the rotation preventing portion 70, the rotation shaft 51a, etc. can be suppressed.

[0092] Further, in the excavation working machine 1, the first shaft (rotation shaft 51a) is inseparably fitted into the fitting hole portion 71 formed in the rotation preventing portion 70 at the upper part.

[0093] According to such an excavation work machine 1, by integrally providing the rotation prevention portion 70 on the first shaft (rotation shaft 51a), an operator can use the rotation prevention portion 70 as a handle or the like when attaching and detaching the first shaft (rotation shaft 51a). Thereby, the assembly work can be made efficient without damaging the first shaft (rotation shaft 51a).

[0094] Further, the excavation work machine 1 is provided with a separation bolt hole (female screw hole 72) in the rotation prevention portion 70 for screwing a separation bolt when separating the first shaft (rotation shaft 51a) from the boom bracket 42.

[0095] According to such an excavation work machine 1, since the first shaft (rotation shaft 51a) can be pulled out through the rotation prevention portion 70, the workability of maintenance can be improved. Further, the female screw hole 72 is formed at the rear portion of the rotation prevention portion 70 so as to be located in the vicinity of the rear end portion of the boss portion 45a of the boom bracket 42 in the front-rear direction. According to such a configuration, it is easy to secure a work space for screwing the separation bolt above the female screw hole 72, so that good workability can be obtained.

[0096] The description of the above-described embodiment is an example of the present invention, and the work machine according to the present invention is not limited to the above-described embodiment. The configurations of the above-described embodiments and the configurations of the modification examples can be appropriately combined. Therefore, even outside the above-described embodiments, various changes can be made according to the design or the like as long as the technical idea according to the present invention is not deviated. Further, the effects described in the present disclosure are merely examples and are not limited, and there may be other effects.

[0097] Note that the present invention can take the following aspects. (1) A boom bracket that is rotatably supported by a slewing frame via a first shaft having an axial direction in the vertical direction of the machine body, and that rotatably supports a working device in the vertical direction via a second shaft disposed above the first shaft, In the boom bracket, A rotation prevention part that is connected to the upper part of the first shaft and restricts the rotation of the first shaft with respect to the boom bracket; A pair of holding parts that are arranged with the first shaft therebetween and hold the rotation prevention part with respect to the boom bracket; A working machine, characterized in that the above are provided. (2) The holding part includes a holding part main body part and a fixing member that fixes the holding part main body part to the boom bracket. The working machine according to (1) above. (3) A hose guide that is installed between the pair of holding parts and restricts contact between a hydraulic hose disposed between the first shaft and the second shaft and the rotation prevention part and the pair of fixing members. The working machine according to (2) above. (4) The hose guide is arranged so that at least a part thereof faces the upper end of the first shaft. The working machine according to (3) above. (5) The holding part main body part has a holding plate part that restricts upward movement of the first shaft with respect to the boom bracket by abutting against the rotation prevention part, and a convex part that protrudes from the lower surface of the holding plate part and restricts rotation of the first shaft with respect to the boom bracket by abutting against the rotation prevention part. The rotation prevention part is provided with a receiving part for receiving the convex part. The fixing member is a bolt that is inserted through a bolt insertion hole that penetrates the holding plate part and the convex part. The working machine according to (3) above. (6) An end part of the hose guide is connected to the upper surface of the holding plate part. The working machine according to (5) above. (7) The rotation prevention part is formed of a plate body. The receiving part is a concave notch formed by notching inward from the side end surface of the plate body. The working machine according to the above (5) or (6). (8) The height of the convex portion is greater than the plate thickness of the anti-rotation portion. The working machine according to the above (7). (9) The upper part of the first shaft is inseparably fitted into the fitting hole formed in the anti-rotation portion. The working machine according to any one of the above (1) to (8). (10) The anti-rotation portion is formed with a separation bolt hole for screwing a separation bolt when separating the first shaft from the boom bracket. The working machine according to the above (9).

[0098] 1 Excavation working machine (working machine) 2 Traveling vehicle body (machine body) 3 Excavation device (working device) 5 Traveling part 7 Swing frame 10 Cabin 20A Lower traveling body 20B Upper swing body 21 Boom 22 Arm 26 Boom cylinder 29 Swing cylinder 41 Support bracket 42 Boom bracket 45 Connecting part 45a Boss part 45c Upper end face 46 Connecting part 48 Rotating support shaft (second shaft) 49 Rotating support shaft 51a Rotating shaft (first shaft) 55 Hydraulic hose 60 Hydraulic hose holding device 70 Anti-rotation part 71 Fitting hole part 72 Female screw hole (separation bolt hole) 73 Concave notch part (receiving part) 74 Holding part main body part 75 Holding part 76 Holding plate part 77 Protrusion 78 Bolt (fixing member) 79 Hose guide 89 Hose guide 99 Hose guide

Claims

1. A boom bracket that is rotatably supported on a swivel frame via a first axis with the vertical direction of the machine body as the axial direction, and rotatably supports a working device in the vertical direction via a second axis disposed above the first axis. In the boom bracket, A rotation prevention portion that is connected to the upper portion of the first axis and restricts the rotation of the first axis with respect to the boom bracket, A pair of holding portions that are disposed sandwiching the first axis and hold the rotation prevention portion with respect to the boom bracket, A working machine, characterized in that it is provided.

2. The holding portion includes a holding portion main body portion and a fixing member that fixes the holding portion main body portion to the boom bracket. The working machine according to claim 1.

3. A hose guide is provided between the pair of holding portions, which restricts contact of a hydraulic hose disposed between the first axis and the second axis with the rotation prevention portion and the pair of fixing members. The working machine according to claim 2.

4. The hose guide is disposed so as to face at least a part of the upper end of the first axis. The working machine according to claim 3.

5. The holding portion main body portion has a holding plate portion that restricts upward movement of the first axis with respect to the boom bracket by abutting against the rotation prevention portion, and a convex portion that protrudes from the lower surface of the holding plate portion and restricts rotation of the first axis with respect to the boom bracket by abutting against the rotation prevention portion. The rotation prevention portion is provided with a receiving portion for receiving the convex portion. The fixing member is a bolt inserted through a bolt insertion hole that penetrates the holding plate portion and the convex portion. The working machine according to claim 3.

6. An end portion of the hose guide is connected to the upper surface of the holding plate portion. The working machine according to claim 5.

7. The rotation prevention portion is formed of a plate body. The receiving portion is a concave notch formed by notching inward from the side end surface of the plate body. The working machine according to claim 6.

8. The height of the convex portion is greater than the plate thickness of the rotation prevention portion. The working machine according to claim 7.

9. The upper portion of the first axis is inseparably fitted into a fitting hole portion formed in the rotation prevention portion. The working machine according to any one of claims 1 to 8.

10. The anti-rotation portion is formed with a separation bolt hole for screwing a separation bolt when separating the first shaft from the boom bracket. The working machine according to claim 9.

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