JP2010013809A - Boom structure of backhoe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the whole boom easily and inexpensively manufacturable by reducing welded parts of a boom end member to the utmost. <P>SOLUTION: A boom body 15, which is provided with a pair of right and left side plates 18 and upper and lower plates 19 and 20, is composed of a sheet metal; the boom end member 16, which is provided with the pair of right and left side plates 18 and a connecting wall 37 for connecting the sidewalls 18, is formed of a casting; a pair of connecting boss portions 26 with a mounting hole is integrally formed on the leading end sides of the pair of sidewalls 36 of the boom end member 16; an arm stopper 45 for regulating the swing of an arm to a boom side is integrally provided on the lower end side of the boom end member 16; a pair of mounting pieces 38 protruding to a base end side with respect to the connecting wall 37 is integrally provided on the base end side of the a pair of sidewalls 36; the pair of mounting pieces 38 is externally fitted between the pair of sidewalls of the boom body 15 so that the pair of mounting pieces 38 and leading ends of the pair of side plates 18 of the boom body 15 can overlap one another; and the pair of side plates 18 and the pair of mounting pieces 38 are welded to one another. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a boom structure of a backhoe in a working machine such as a TLB provided with a front loader at a front portion of a tractor and a backhoe at a rear portion.

There is a work machine called TLB with a front loader at the front of the tractor and a backhoe at the rear of the tractor. The backhoe of this work machine has a boom base end that can swing up and down on the tractor side. The boom is provided with a connecting boss at the tip of the boom, and the base end of the arm is pivotally supported at the tip of the boom via the connecting boss so that it can swing back and forth around the horizontal axis. A bucket is attached to the section, and an arm cylinder that swings the arm back and forth is provided between the boom and the arm. In this type of tractor-mounted boom, a boom tip member having a mounting boss portion is formed separately from the boom body, and the boom tip member is a connecting wall that connects a pair of left and right side walls or a pair of left and right side walls. However, the boom tip member is made of sheet metal like the boom body, and is integrated by welding a pair of left and right side walls and a connecting wall and welding a mounting boss to the pair of side walls. Further, the boom is formed by welding the integrated boom tip member to the tip side of the boom body and integrating them (Patent Documents 1 and 2). When the boom tip member is provided with an arm stopper for restricting the swing of the arm to the boom side, it is necessary to weld the arm stopper to the lower end of the boom tip member.
JP 2007-255150 A JP 2006-37644 A

Therefore, conventionally, there are many welded portions of the boom tip member, and the weld length is increased, which increases the manufacturing cost of the boom.
In view of the above-described problems, the present invention is to reduce the welded portion of the boom tip member as much as possible, so that the entire boom can be manufactured easily and inexpensively.

The technical means of the present invention for solving this technical problem is that a connecting boss portion is provided at the distal end portion, and the base end portion of the arm is pivotally supported around the horizontal axis so as to be swingable back and forth through the connecting boss portion. Backhoe boom structure,
A boom body having a pair of left and right side plates and an upper plate that connects between the upper ends of the pair of side plates and a lower plate that connects between the lower ends of the pair of side plates is made of sheet metal, and connects the pair of left and right side walls and the pair of left and right side walls. A boom tip member having a connecting wall to be formed by casting,
A pair of connecting bosses having mounting holes are integrally formed on the distal end sides of the pair of side walls of the boom tip member, and an arm stopper for restricting the swing of the arm toward the boom side is integrally formed on the lower end side of the boom tip member. A pair of mounting pieces projecting proximally from the connecting wall is integrally provided on the base end side of the pair of side walls, and the pair of mounting pieces and the tip ends of the pair of side plates of the boom body are provided. The pair of attachment pieces are fitted between the pair of side plates of the boom body so that they overlap each other, and the pair of side plates and the pair of attachment pieces are welded to each other.

In another technical means of the present invention, the upper plate and the lower plate of the boom body are arranged above and below the pair of attachment pieces so as to sandwich the pair of left and right attachment pieces up and down, and the tip of the upper plate is The point where the upper end of the connecting wall is in contact with or close to the upper end of the connecting wall and welded to the upper end of the connecting wall, and the lower plate is in contact with or in close proximity to the lower end of the connecting wall and welded to the lower end of the connecting wall. It is in.
According to another technical means of the present invention, the connection wall includes a lower connection portion that connects the lower end portions of the pair of left and right side walls, and an upper connection portion that connects the upper end portions of the pair of left and right side walls. The tip of the lower plate of the boom body is abutted or approached to the lower connecting portion and fixed by welding, and the tip of the upper plate of the boom body is contacted or approached to the upper connecting portion and fixed by welding, the lower connecting portion The arm stopper is integrally formed so as to protrude downward.

Another technical means of the present invention is that a pair of left and right mounting pieces are provided with welding holes penetrating in the left-right direction, and the opening edge of the welding hole is welded to the tip of the side plate of the boom body. is there.
Further, according to another technical means of the present invention, the left and right side portions of the top plate tip part protrude outward in the left-right direction with respect to the pair of side plates, and the pair of mounting pieces together with the side plates on the bottom surfaces of both side parts of the top plate tip part. The left and right side portions of the lower plate of the boom body are welded and protrude outward in the left-right direction from the pair of side plates, and the pair of attachment pieces are welded to the upper surfaces of both side portions of the lower plate together with the side plates.
Further, according to another technical means of the present invention, the lower surfaces of the left and right side portions of the top plate front end portion and the upper end surfaces of the pair of mounting pieces are inclined with respect to each other so as to be gradually separated toward the base end side of the boom. The pair of mounting pieces are welded to the both side portions of the upper plate front end portion together with the side plate at the separated portion, and the lower surfaces of the left and right side portions of the lower plate front end portion and the lower end surfaces of the pair of mounting pieces are directed toward the base end side of the boom. The pair of attachment pieces are welded to both side portions of the lower plate together with the side plate at the separated portions.

According to the present invention, when a boom tip member formed of a casting is attached to a boom body made of sheet metal, by fitting the pair of left and right attachment pieces of the boom tip member on the tip side of the boom body so as to be externally fitted. The pair of attachment pieces and the tip end portions of the pair of side plates of the boom body are overlapped with each other, and the pair of attachment pieces are easily fitted between the pair of side walls, and the boom tip member has a pair of connecting boss portions and an arm stopper. The boom tip member can be easily positioned with respect to the boom body.
Therefore, the boom tip member may be fitted and welded to the boom body, and the boom tip member can be easily welded and fixed to the boom body, so that the boom body and the boom tip member can be easily welded. The entire boom can be easily manufactured. Further, it is not necessary to weld and integrate the pair of left and right side walls and the connecting wall of the boom tip member, and it is not necessary to weld and integrate the mounting boss part to the pair of side walls. Further, it is not necessary to weld an arm stopper to the lower end side of the boom tip member, and it is not necessary to weld the components of the boom tip member individually. From this point, the manufacture of the boom 7 as a whole is facilitated.

  The arm stopper is formed integrally with the boom tip member, and the tip of the lower plate of the boom main body and the lower connecting portion formed integrally with the arm stopper are directly welded. The force received by the arm is received at the tip of the boom body through the boom tip member, and no special reinforcement is required, and the arm stopper part can be firmly configured with a very simple structure. The whole boom can be manufactured easily and inexpensively.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 5 illustrates a backhoe 1 that is detachably attached to the rear portion of the tractor. In addition, while providing a front loader in the front part of a tractor and providing the backhoe 1 shown in FIG. 5 in a rear part, TLB (work vehicle) is comprised.
The backhoe 1 includes a main frame 2 that is detachably connected to the rear portion of the tractor, a swing bracket 3 that is supported on the rear portion of the main frame 2 so as to be able to swing left and right about a vertical axis, and the swing bracket. The swing cylinder 4 for swinging the left and right 3, the excavation work device 5 attached to the swing bracket 3, the control box 6 provided on the upper part of the main frame 2, and the left and right sides of the main frame 2 are provided. And an outrigger device (not shown).

The excavation work device 5 includes a boom 7 whose base side is pivotally connected to the front lower portion of the swing bracket 3 so as to be swingable about a horizontal axis, and a base side about the horizontal axis about the distal end side of the boom 7. The arm 8 is pivotally connected so as to be swingable, and the bucket 9 is pivotally connected to the distal end side of the arm 8 so as to be swingable around a left and right axis.
The excavation work device 5 includes a boom cylinder 10 that swings the boom 7, an arm cylinder 11 that swings the arm 8, and a bucket cylinder 12 that swings the bucket 9. , 12 are hydraulic cylinders.

1 to 5, the boom 7 includes a boom main body 15 and a boom tip member 16 which are bent in a dogleg shape, the boom main body 15 is made of sheet metal, and the boom tip member 16 is a kind of casting. It is integrally formed of cast steel. The boom body 15 includes a pair of left and right side plates 18, an upper plate 19 that connects between the upper ends of the pair of side plates 18, and a lower plate 20 that connects between the lower ends of the pair of side plates 18, and is formed in a cylindrical shape having a rectangular cross section. ing.
A pair of left and right bracket plates 23 are provided on the base side of the boom body 15, and a pair of left and right connecting boss portions 24 are provided on the pair of bracket plates 23, and the horizontal shaft 25 is inserted between the connecting boss portions 24. The base of the boom 7 is pivotally connected to the swing bracket 3. A base end portion of the arm 8 is pivotally supported around the horizontal shaft 27 at a front end portion of the boom 3 via a connecting boss portion 26 described later.

A pair of left and right bracket plates 28 are provided in the middle portion of the upper plate 19 of the boom body 15 in the boom longitudinal direction. Between the pair of bracket plates 28, the piston top side of the cylinder body 10 a of the boom cylinder 10 and the arm cylinder 11. A piston top side of the cylinder body 11a is pivotally connected via a pivot 30 so as to be rotatable about a left and right axis.
The distal end side of the piston rod of the boom cylinder 10 is pivotally connected to the swing bracket 3 via the pivot 32 so as to be rotatable about the left and right axis, and the distal end side of the piston rod of the arm cylinder 11 is connected to the base side of the arm 8. A pair of left and right bracket plates 31 are pivotally connected via a pivot 33 so as to be rotatable about the left and right axes. Thereby, the boom 7 swings up and down by the expansion and contraction of the boom cylinder 10, and the arm 8 swings back and forth by the expansion and contraction of the arm cylinder 11. As shown in FIGS. 1, 2, and 4, a hose holding member 35 for holding a hydraulic hose is attached to the distal end side of the upper plate 19 of the boom body 15 by welding or the like.

  As shown in FIGS. 1 to 4, the boom tip member 16 formed of cast steel has a pair of left and right side walls 36 and a connecting wall 37 that connects the pair of left and right side walls 36. A pair of connecting boss portions 26 are integrally formed at the distal end side of the pair of side walls 36 of the boom distal end member 16, and a pair of left and right sides projecting proximally from the coupling wall 37 to the proximal end side of the pair of side walls 36. The attachment piece 38 is integrally provided. The pair of connecting boss portions 26 have a cylindrical shape having mounting holes 39 and protrude from the side walls 36 to both sides in the left-right direction. By inserting the horizontal shaft 27 between the connecting boss portions 26 of the boom distal end member 16, the base end portion of the arm 8 swings back and forth around the horizontal shaft 27 via the connecting boss portion 26 at the distal end portion of the boom 7 as described above. It is pivotally supported. A recess 40 that is recessed inward in the left-right direction is provided on the outer surface side of the pair of side walls 36.

  The connecting wall 37 includes a lower connecting portion 41 that connects the lower end portions of the pair of left and right side walls 36, an upper connecting portion 42 that connects the upper end portions of the pair of left and right side walls 36, and an upper portion from the distal end portion of the lower connecting portion 41. The upright connecting portion 43 projecting from the upper connecting portion 42 and the inclined connecting portion 44 inclined downward from the upper connecting portion 42 toward the upper end of the upright connecting portion 43 are integrally provided. An arm stopper 45 is integrally provided on the lower end side of the boom tip member 16. The arm stopper 45 regulates the swing of the arm 8 toward the boom 7 and is integrally formed with the lower connecting portion 41 so as to protrude downward in a triangular shape.

A pair of left and right first reinforcing ribs 48 are provided on the attachment piece 38 side of the pair of left and right side walls 36. The pair of first reinforcing ribs 48 protrudes inward in the left-right direction on the pair of side walls 36, and vertically connects the upper connecting portion 42 and the lower connecting portion 41 of the connecting wall 37 (the tip of the boom). The width direction of the member 16 is arranged.
A pair of left and right second reinforcing ribs 49 are provided between the connecting wall 37 of the pair of left and right side walls 36 and the pair of connecting boss portions 26. The pair of second reinforcing ribs 49 project inward in the left-right direction on the pair of side walls 36 and extend in the longitudinal direction of the boom tip member 16 so as to connect the connecting wall 37 and the inward protruding portion of the connecting boss portion 26. Has been placed.

The pair of attachment pieces 38 are fitted between the pair of side walls 36 of the boom body 15 so that the pair of attachment pieces 38 and the tip ends of the pair of side plates 18 of the boom body 15 are overlapped with each other. A pair of attachment pieces 38 are welded together. In other words, the outer peripheral edges of the pair of attachment pieces 38 are welded to the outer surfaces of the side plates 18 as indicated by hatching in FIG.
The upper plate 19 and the lower plate 20 at the tip of the boom body 15 are arranged above and below the pair of attachment pieces 38 so as to sandwich the pair of left and right attachment pieces 38 above and below. The tip of the lower plate 20 of the boom main body 15 is brought into contact with or close to the lower connecting portion 41 which is the lower end portion of the connecting wall 37 and fixed by welding, and the tip of the upper plate 19 of the boom main body 15 is connected to the connecting wall 37. The upper connection part 42 which is the upper end part is contacted or brought close to the upper connection part 42 and fixed by welding.

A pair of left and right mounting pieces 38 are provided with welding holes 51 penetrating in the left-right direction, and an opening edge portion of the welding hole 51 is welded to the distal end portion of the side plate 18 of the boom body 15 as shown by hatching in FIG.
The left and right sides of the upper plate 19 (at least the tip of the upper plate 19) protrude outward in the left-right direction with respect to the pair of side plates 18, and the pair of attachment pieces 38 are welded together with the side plate 18 to the lower surfaces of both sides of the tip of the upper plate 19. The left and right side portions of the lower plate 20 (at least the tip of the lower plate 20) of the boom body 15 protrude outward in the left-right direction with respect to the pair of side plates 18, and the pair of attachment pieces 38 together with the side plates 18 of the lower plate 20. It is welded to the upper surface of both sides.

More specifically, as shown in FIG. 1, the lower surfaces of the left and right side portions of the distal end portion of the upper plate 19 and the upper end surfaces of the pair of attachment pieces 38 are gradually separated from each other toward the proximal end side of the boom 7. The pair of attachment pieces 38 are welded to both side portions of the front plate 19 along with the side plate 18 at the separated portion. Further, the lower surfaces of the left and right side portions of the front end portion of the lower plate 20 and the lower end surfaces of the pair of attachment pieces 38 are inclined with respect to each other so as to be gradually separated toward the base end side of the boom 7. The attachment pieces 38 are welded to both side portions of the lower plate 20 together with the side plates 18.
According to the above embodiment, when the boom tip member 16 is attached to the boom body 15, by fitting the pair of left and right attachment pieces 38 of the boom tip member 16 on the tip side of the boom body 15, The pair of attachment pieces 38 and the tip end portions of the pair of side plates 18 of the boom body 15 are overlapped with each other, and the pair of attachment pieces 38 are easily fitted between the pair of side walls 36. The upper plate 19 and the lower plate 20 at the tip of the boom body 15 are arranged above and below the pair of attachment pieces 38 so as to sandwich the pair of left and right attachment pieces 38 up and down. The front end is in contact with or close to the lower connection portion 41 that is the lower end portion of the connection wall 37, and the front end of the upper plate 19 of the boom body 15 is in contact with or in proximity to the upper connection portion 42 that is the upper end portion of the connection wall 37. Is done. For this reason, the boom tip member 16 formed of cast steel has an integral structure including the pair of connecting boss portions 26 and the arm stopper 45, and is fitted to the tip side of the boom body 15 so that the boom tip member 16 is attached to the boom body 15. And can be positioned easily.

  As a result, thereafter, the outer peripheral edges of the pair of mounting pieces 38 are respectively welded to the outer surfaces of the side plates 18 as indicated by hatching in FIG. What is necessary is just to weld a pair of attachment piece 38 to the upper surface of the both sides of the lower board 20 with the side board 18 while welding to a lower surface. Further, as shown by oblique lines in FIG. 1, the opening edge portion of the welding hole 51 of each mounting piece 38 is welded to the tip portion of the pair of side plates 18, and the tip of the lower plate 20 of the boom body 15 and the lower connecting portion 41 are connected. What is necessary is just to weld and the front-end | tip of the upper board 19 of the boom main body 15, and the upper connection part 42 should be welded. Therefore, when the boom tip member 16 formed of cast steel is attached to the boom body 15, the boom tip member 16 is fitted into the boom body 15, and the upper ends of the connecting walls 37 are fitted to the tips of the upper plate 19 and the lower plate 20 of the boom body 15. The boom tip member 16 can be easily welded and fixed to the boom body 15, and the boom body 15 and the boom tip member 16 can be welded easily. The entire boom 7 can be easily manufactured. At this time, the arm stopper 45 provided on the lower end side of the boom distal end member 16 is integrally connected to the distal end side of the boom main body 15 by the lower connection portion 41 of the connection wall 37.

Therefore, it is not necessary to weld and integrate the pair of left and right side walls 36 and the connecting wall 37 of the boom tip member 16, and it is not necessary to weld and integrate the mounting boss portion 26 to the pair of side walls 36. Further, it is not necessary to weld the arm stopper 45 to the lower end side of the boom tip member 16, and it is not necessary to weld the components of the boom tip member 16 individually. From this point, the manufacture of the entire boom 7 is facilitated. .
Then, after the boom tip member 16 is attached to the boom main body 15, when the arm 8 of the backhoe 1 is pushed in contact with another object when the loader operation is performed, the arm stopper 45 causes the arm 8 to move further. The swinging to the boom 7 side can be stopped so that a large tensile force is not applied to the arm cylinder 11. In this case, the base side of the arm 8 contacts the arm stopper 45 and the arm stopper 45 receives a large force from the arm 8 side toward the base end side. Since the tip of the lower plate 20 of the boom body 15 and the lower connecting portion 41 formed integrally with the arm stopper 45 are directly welded, the force applied to the arm stopper 45 is as follows. The arm stopper 45 is received at the front end side of the boom main body 15 through the boom front end member 16, and no special reinforcement is required, and the arm stopper 45 portion can be firmly configured with a very simple structure.

  In the above-described embodiment, the boom tip member 16 is integrally formed of cast steel, which is a type of casting, but instead, the arm tip member is integrally formed of cast iron other than cast steel or other castings. Also good.

It is a side view of the front end side of the boom which shows one embodiment of this invention. It is a top view of the front end side of the boom. It is a bottom view of the front end side of the boom. It is a side view of the boom. It is a side view of the backhoe.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Backhoe 8 Arm 15 Boom main body 16 Boom tip member 18 Side plate 19 Upper plate 20 Lower plate 26 Connection boss part 27 Horizontal axis 36 Side wall 37 Connection wall 38 Mounting piece 41 Lower connection part 42 Upper connection part 51 Welding hole

Claims (6)

A backhoe boom is provided with a connecting boss portion (26) at the distal end and the arm (the base end portion of 8 is pivoted back and forth around the horizontal axis (27) via the connecting boss portion (26). Structure,
A boom body (15) having a pair of left and right side plates (18), an upper plate (19) for connecting the upper ends of the pair of side plates (18), and a lower plate (20) for connecting the lower ends of the pair of side plates (18). ) Is made of sheet metal, and a boom tip member (16) having a pair of left and right side walls (36) and a connecting wall (37) connecting the pair of left and right side walls (36) is formed of a casting,
A pair of connecting boss portions (26) having attachment holes (39) are integrally formed on the distal end sides of the pair of side walls (36) of the boom distal end member (16), and on the lower end side of the boom distal end member (16), An arm stopper (45) for restricting the swing of the arm (8) to the boom (7) side is integrally provided, and is closer to the base end side of the pair of side walls (36) than the connecting wall (37). A pair of mounting pieces (38) projecting to each other are integrally provided, and the pair of mounting pieces (38) and the pair of side plates (18) of the boom body (15) are overlapped with each other so that they overlap each other. The mounting piece (38) is externally fitted between the pair of side plates (18) of the boom body (15), and the pair of side plates (18) and the pair of mounting pieces (38) are welded to each other. Backhoe boom structure.   The upper plate (19) and the lower plate (20) of the boom body (15) are arranged above and below the pair of attachment pieces (38) so as to sandwich the pair of left and right attachment pieces (38) up and down. 19) the front end of the connecting wall (37) contacts or approaches the upper end of the connecting wall (37) and is welded to the upper end of the connecting wall (37), and the lower end of the lower plate (20) is the lower end of the connecting wall (37). The boom structure of a backhoe according to claim 1, wherein the boom structure is welded to a lower end portion of the connecting wall (37) so as to be in contact with or close to the connecting wall (37).   The connecting wall (37) includes a lower connecting portion (41) for connecting the lower ends of the pair of left and right side walls (36), and an upper connecting portion (42) for connecting the upper ends of the pair of left and right side walls (36). And the tip of the lower plate (20) of the boom body (15) contacts or approaches the lower connecting portion (41) and is fixed by welding, and the tip of the upper plate (19) of the boom body (15) The arm stopper (45) is formed integrally with the lower connecting part (41) so as to protrude downwardly by contacting or approaching the upper connecting part (42) and being fixed by welding. The boom structure of the backhoe as described in 1 or 2.   A pair of left and right mounting pieces (38) is provided with a welding hole (51) penetrating in the left-right direction, and an opening edge of the welding hole (51) is welded to the tip of the side plate (18) of the boom body (15). The backhoe boom structure according to any one of claims 1 to 3, wherein:   The left and right sides of the tip of the upper plate (19) protrude outward in the left-right direction from the pair of side plates (18), and the pair of mounting pieces (38) together with the side plate (18) are on both sides of the tip of the upper plate (19). The left and right side portions of the lower plate (20) of the boom body (15) are protruded outward in the left-right direction from the pair of side plates (18), and the pair of attachment pieces (38) are side plates (18). The boom structure of the backhoe according to any one of claims 1 to 4, wherein the boom is welded to both upper surfaces of the lower plate (20).   The lower surfaces of the left and right sides of the tip of the upper plate (19) and the upper end surfaces of the pair of mounting pieces (38) are inclined with respect to each other so as to be gradually separated toward the base end side of the boom (7). A pair of attachment pieces (38) are welded to both sides of the tip of the upper plate (19) together with the side plate (18), and the lower surface of the left and right sides of the tip of the lower plate (20) and the pair of attachment pieces (38). The lower end surface is inclined with respect to the base end side of the boom (7) so as to be gradually separated from each other, and the pair of attachment pieces (38) together with the side plate (18) of the lower plate (20) are separated from each other. The backhoe boom structure according to claim 5, wherein the backhoe boom structure is welded to both sides.

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