JP2002242227A - Work arm structure for work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of members and welded junctions for a work arm welded to form a hollow cross section and having the reinforcing members arranged to practically close the hollow cross section. SOLUTION: The reinforcing members 30, 32, 34 arranged to practically close the hollow cross section of the welded work arm 6 form the backing metals of the junctions of the members constituting the work arm 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a working arm structure of a working machine, and more particularly, to the arrangement of a reinforcing member having a hollow cross section and a backing metal at a joining portion of a working arm having a hollow cross section. Regarding the structure.

[0002]

2. Description of the Related Art Working machines such as construction machines and cargo handling machines are:
It has one or a plurality of connected working arms to which working tools and the like are attached. 2. Description of the Related Art A hydraulic excavator, which is a typical working machine, includes a boom, which is a working arm, which is swingably attached to a body of a machine body, and an arm, which is swingably attached to a tip of the boom. A bucket, which is a working tool, is swingably attached to the tip of the arm.

[0003] The structure of the working arm will be described with reference to Figs. A boom, generally designated by the numeral 50, is formed by welding various steel members to each other, and includes an upper surface plate 52, a lower surface plate 54, and a left side plate 5
6, and a right side plate 58, and is formed in a box-shaped structure having a rectangular cross section (FIG. 8). A forked member 60 for connecting to the arm is attached to one end in the longitudinal direction of the box-shaped structure, and a cylindrical member 62 for connecting to the body body is attached to the other end.

An upper plate 52, a lower plate 54, a left side plate 56,
Each of the right side plate 58 and the right side plate 58 is divided in the longitudinal direction in order to partially change the plate thickness in terms of strength, and to improve the yield of the material, and the divided members are joined and joined together. ing. The forked member 60 includes an upper plate 52, a lower plate 54, a left side plate 56, and a right side plate 5
8 are joined to each other. These joints are shown in FIG.
As shown in FIG. 7, a gap S is provided between the members in order to absorb variations in the molding dimensions of the members, and a strip-shaped backing metal 64 is applied to the gap S, so that the members and the members are Money 6
4 and joined together. In the hollow box-shaped cross section of the boom 50, a reinforcing plate 66 formed by molding a plate member into a rectangular shape, which is attached so as to substantially close the box-shaped cross section, to increase torsional rigidity. , 68, 70 are provided.

[0005]

The structure of the conventional working arm of the above-described embodiment has the following problems to be solved.

That is, the reinforcing member provided in the hollow section of the welding arm having the hollow section and the backing metal provided in the joint between the members are different members. However, the number of members constituting the above-mentioned components increases, and it is necessary to separately prepare jigs for welding and joining them, and the welding time becomes longer and the production cost of the working arm becomes higher.

The present invention has been made in view of the above-mentioned circumstances, and a technical problem thereof is to provide a working arm having a reinforcing member which is welded to have a hollow cross section and which is disposed so as to substantially close the hollow cross section. It is an object of the present invention to provide a working arm structure of a working machine which can reduce the number of members and a welded joint.

[0008]

According to the first aspect of the present invention, there is provided a welding arm having a hollow cross section, wherein a reinforcing member disposed to substantially close the hollow cross section is provided with a reinforcing member. A working arm structure of a working machine, wherein a backing metal is formed at a joint portion of members forming an arm.

Further, the structure is such that the reinforcing material also serves as the backing metal, so that the number of members and the welded portion can be reduced.

According to a second aspect of the present invention, in the working arm structure for a working machine according to the first aspect, the working arm has a longitudinally extending upper surface plate and a lower surface plate for forming the hollow cross section into a rectangular shape. And a connecting member joined to at least one open end of the working arm, wherein the connecting member has a U-shaped cross section and each of the U-shaped ends is the top plate. And an end plate respectively joined to the lower plate, and a pair of connecting plates joined to the left and right sides of the end plate and each of the left and right side plates, the upper plate and the lower plate and the end plate Is provided with the reinforcing member.

Further, the structure of the forked connecting member provided at the end of the working arm can be simplified.

According to a third aspect of the present invention, in the working arm structure for a working machine according to the second aspect, the joining position of the upper and lower plates and the end plate in the longitudinal direction of the working arm is: The connection member is positioned on the distal end side of the connection member with respect to the joint position between each of the left and right side plates and each of the pair of connection plates.

The joint between the end plate and the upper plate and the lower plate in the joint portion of the connecting member is positioned at the joint plate, and the joint between the end plate and the upper plate and the lower plate is formed. The applied load is reduced by joining with the connecting plate, so that the connecting member can be configured more firmly.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A working arm structure of a working machine constituted according to the present invention will be described below with reference to the accompanying drawings showing a preferred embodiment of a working arm provided in a hydraulic shovel as a typical working machine. This will be described in more detail with reference to FIG.

Referring to FIG.
A hydraulic excavator indicated by a boom 6 is a working arm, which is attached to a body body 4 so as to be vertically swingable, and a boom 6
The arm 8 is attached to the tip of the arm so as to be vertically swingable. A bucket 10, which is a working tool, is swingably attached to the tip of the arm 8. A boom operating cylinder 12 is provided between the body 4 and the boom 6, an arm operating cylinder 14 is provided between the boom 6 and the arm 8, a bucket operating cylinder 16 is provided between the arm 8 and the bucket 10,
Each is interposed.

Referring to FIG. 2, the structure of the working arm will be described using a boom 6 which is a typical working arm. The boom 6 is formed in a box shape having a rectangular hollow cross section by welding various steel members to each other. That is, the boom 6 extends in the longitudinal direction, and includes the upper surface plate 18, the lower surface plate 20, and the left side surface plate 2.
2, a fork member 26 which is a connecting member for connecting to the arm 8 at one end in the longitudinal direction.
However, the other end has a cylindrical member 28 for connecting to the body of the body.
Are respectively attached. The reinforcing plate 3 is a reinforcing member disposed so as to substantially close the hollow cross section from the end where the bifurcated member 26 is attached to the rectangular hollow cross section.
0, a reinforcing plate 32, and a reinforcing plate 34 are sequentially provided.

First, the structure of the main body of the boom 6 will be described with reference to FIG. 2 and FIG. For example, the left side plate 22 constituting a rectangular cross section is used to partially change the thickness in terms of strength, and to improve the yield of the material.
The boom 6 is divided into a plate 22a, a plate 22b, and a plate 22c sequentially from the end side to which the bifurcated member 26 is attached in the longitudinal direction and is integrally joined. At each joint,
A gap S (FIG. 3) is provided to absorb variations in the molding dimensions of the respective plates so that they do not interfere with each other. Reinforcing plates 32 and 34 are positioned in the gap S, and the plates 22a and 22b are The plate 22b and the plate 22c are integrally joined with the reinforcing plate 32 as a backing plate and the reinforcing plate 34 as a backing plate. The reinforcing plates 32 and 34 are formed by cutting and forming a relatively thick plate material. FIG. 2
Although not shown in the figure, each of the upper surface plate 18, the lower surface plate 20, and the right side surface plate 24 is appropriately divided as necessary and similarly joined.

Next, the structure of the forked member 26 will be described with reference to FIGS. The forked member 26 has a U-shaped cross section, and each of the U-shaped tips has an upper surface plate 1.
8 and an end plate 36 respectively joined to the lower surface plate 20, and a pair of left and right connecting plates 38, 38 joined to the left side plate 22 and the right side plate 24, respectively, and the end plate 36. A reinforcing plate 30 is also provided at the joint between the upper and lower plates 18 and 20 and the end plate 36 as a backing metal.

The end plate 36 is formed by bending a plate member having a width W between the pair of connecting plates 38, 38 into a U-shape. The connecting plate 38 is formed of a relatively thick plate, and a connecting hole 38a is formed on the same axis 39 at the tip of each of the pair of connecting plates 38, 38. In the longitudinal direction of the boom 6, the joint position between the upper surface plate 18 and the lower surface plate 20 and the end plate 36 is a bifurcated member with respect to the joint position between the left side plate 22, the right side plate 24 and each of the pair of connecting plates 38, 38. 26, it is positioned at a distance L away from the distal end. Reinforcement plate 30
Are formed by bending the edges of the pair of connecting plates 38, 38 and the end plate 36 into a rectangular dish shape having a rectangular cross-sectional size formed by a U-shape. This edge is positioned at the joint between the upper plate 18 and the lower plate 20 and the end plate 36. At the joint between the left side plate 22 and the right side plate 24 and the pair of connecting plates 38, 38, a band-shaped backing metal 40 is provided.

The operation of the working arm structure as described above will be described.

(1) Reduction of the number of members: The reinforcing members 30, 3 of the boom 6 which is a welding-configured working arm having a hollow cross section.
By employing a structure in which the members 2 and 34 also serve as the backing metal of the member joining portions, the number of working arms and the number of welding joints can be reduced.

(2) Improvement of strength: Further, the bifurcated member 26, which is a connecting member attached to the end of the working arm, has a simplified structure, and has an end plate 36, an upper plate 18 and a lower plate 20, Are located in the portion of the connecting plate 38 located on the side surface thereof and exist in the range of high rigidity, so that the load acting on the welded portion between the end plate 36 and the upper surface plate 18 and the lower surface plate 20 Is reduced.

As described above, the present invention has been described in detail based on the embodiments. However, the present invention is not limited to the above-described embodiments. It can be modified or modified.

(1) Reinforcing member: In this embodiment, the reinforcing plates 32 and 34 are formed by cutting and forming relatively thick plates, and the reinforcing plate 30 is formed by bending and forming relatively thin plates. The reinforcing plates 32 and 34 may be formed by bending a thin plate, or the reinforcing plate 30 may be formed by cutting and forming a thick plate.

(2) Reinforcing Member: In the present embodiment, the reinforcing plates 30, 32, and 34 are formed in a shape that completely closes the hollow cross section, but depending on the necessity of a backing metal. It is not necessary that the hollow section be completely closed.

(3) Hollow cross section: In the present embodiment, the shape of the hollow cross section is rectangular, but the hollow cross section may be circular or another polygon instead of rectangular.

[0027]

According to the working arm structure of the working machine constructed in accordance with the present invention, the working arm has a reinforcing member which is welded to have a hollow section and which is disposed so as to substantially close the hollow section. A work arm structure of a work machine is provided which can reduce the number of members and the number of welded joints.

[Brief description of the drawings]

FIG. 1 is a side view of a hydraulic shovel, which is a typical work machine having a work arm structure configured according to the present invention.

FIG. 2 is an enlarged perspective view of a boom which is a working arm shown in FIG.

FIG. 3 is an enlarged cross-sectional view of a bonding portion viewed in the direction of arrows AA in FIG. 2;

FIG. 4 is an enlarged side view of the connecting member seen in the direction of arrow B in FIG. 2;

FIG. 5 is a top view of the connecting member as viewed in the direction of arrows CC in FIG. 4;

FIG. 6 is a cross-sectional view as seen in the direction of the arrow DD in FIG. 4;

FIG. 7 is an enlarged perspective view of a boom that is a conventional working arm.

8 is a representative enlarged cross-sectional view of the boom shown in FIG.

FIG. 9 is an enlarged cross-sectional view of the joining portion viewed in the direction of arrows EE in FIG. 7;

[Explanation of symbols]

 2: Hydraulic excavator (working machine) 6: Boom (work arm) 18: Upper surface plate 20: Lower surface plate 22: Left side plate 24: Right side plate 26: Bifurcated member (connection member) 30: Reinforcement plate (reinforcement member) 32: Reinforcement Plate (reinforcement member) 34: reinforcement plate (reinforcement member) 36: end plate 38: connecting plate 50: boom (work arm) 64: backing plate 66: reinforcement plate 68: reinforcement plate 70: reinforcement plate

Claims (3)

[Claims] 1. A welding member having a hollow cross section and a reinforcing member disposed so as to substantially close the hollow cross section forms a backing metal at a joint portion of the members forming the working arm. A working arm structure of a working machine. 2. The work arm includes a longitudinally extending upper surface plate, a lower surface plate, and left and right side plates that form the hollow section in a rectangular shape, and is joined to at least one open end of the work arm. An end plate formed into a U-shaped cross section and each of the ends of the U are respectively joined to the upper surface plate and the lower surface plate, and the left and right sides of the end plate and The work machine according to claim 1, further comprising a pair of connecting plates joined to each of the left and right side plates, wherein the reinforcing member is provided at a joint between the upper and lower plates and the end plate. Working arm structure. 3. The connecting position of the upper and lower plates and the end plate in the longitudinal direction of the working arm is different from the connecting position of each of the left and right side plates and each of the pair of connecting plates. The working arm structure of the working machine according to claim 2, wherein the working arm structure is positioned on a distal end side of the member.