JP2001115480A - Working arm structure of working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a working arm structure of a working machine which can reduce number of parts to be welded and the weight, and improve the strength of the working arm which is formed in a box-shaped section by welding plate members and extended in the longitudinal direction. SOLUTION: The working arm comprises a pair of split arms which are split on the split plane extending in the longitudinal direction, and integrated with each other on the split plane.

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 a working arm structure suitably used for a working arm of a working machine such as an arm of a hydraulic shovel.

[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 long working arms to which a working tool or the like is attached. For example, a hydraulic shovel, which is a typical working machine, is a boom that is a working arm that is vertically swingably attached to a body of a machine body, and a working arm that is vertically swingably attached to a tip of the boom. Arm. A bucket, which is a working tool, is attached to the tip of the arm so as to be vertically swingable.

Since these working arms are formed to be long, they have a sufficient strength against bending, twisting and the like, and are formed in a box-shaped structure by plate members so as to reduce the weight. ing.

Referring to FIG. 6, the working arm will be described by taking the above-mentioned arm as an example. The arm generally designated by reference numeral 50 is formed in a box-shaped structure by welding various steel members to each other. . That is, the arm 50 is formed into a box-shaped structure having a rectangular box-shaped cross section and extending in the longitudinal direction by the upper plate 52, the lower plate 54, the left side plate 56, and the right side plate 58, which are plate members extending in the longitudinal direction. Is formed. A bearing member 60 for connecting to the boom is attached to one end in the longitudinal direction of the box-shaped structure, and a bearing member 62 for connecting to the bucket is attached to the other end.

Referring to FIG. 7 together with FIG.
A baffle plate 64, which is a reinforcing plate member disposed substantially perpendicular to the longitudinal direction of the arm 50, is welded and attached to the inside of the box-shaped cross section. The welding of the baffle plate 64 to the inside of the box-shaped section is performed before the box-shaped structure is completed.
A part of the plate forming the box-shaped cross section, for example, the lower plate 54 is opened without being attached, and the baffle plate 64 is welded to the upper plate 52, the left side plate 56, and the right side plate 58 from the opened part.
Then, the lower plate 54 is connected to the left side plate 5
6 and the right side plate 58 to complete the box-shaped structure.

Referring to FIG. 8 together with FIG. 6,
In order to further reduce the weight of the arm 50 and to provide strength, the upper plate 52, the lower plate 54, the left side plate 56, the right side plate 58, etc. It is divided into two parts. For example, the left side plate 56
Are plates 56a, 56b, 5 from the bearing member 60 side.
6c, the plates 56a and 56 at both ends.
b is formed of a thick plate, and the center plate 56b is formed of a thinner plate. These plates 56a, 56
b and 56c are welded and joined when the box-shaped structure of the arm 50 is completed.

[0007]

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

(1) Productivity: A working arm such as a box-shaped arm 50 is formed by welding and joining many plate members. In addition to the above-described configuration, a mounting bracket for a hydraulic cylinder, a mounting bearing member for an operation link, and the like are also welded to the arm 50. Further, a configuration in which a plate thickness is changed for weight reduction and strength application is finely applied. Therefore, there are many places of welding connection, and improvement of productivity is desired.

(2) Strength of the working arm: Since the baffle plate 64 of the reinforcing plate member provided in the box-shaped section is not welded in a part of the box-shaped section, the reinforcement of the working arm is unbalanced. And the strength is impaired. In addition, the joining of a plurality of plate members on the left side plate 56 by welding increases the number of welded portions, which causes a reduction in fatigue strength of the working arm.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and a technical problem thereof is to reduce the number of welding points and the weight of a working arm formed by welding and joining a plate member to form a box-shaped cross section and extending in the longitudinal direction. Another object of the present invention is to provide a working arm structure of a working machine which further improves strength.

[0011]

According to the present invention, as a working arm structure of a working machine for solving the above technical problem, a working arm formed in a box-shaped cross section by a plate member and extending in a longitudinal direction is provided in the longitudinal direction. A working arm structure of a working machine is provided, wherein the working arm structure is formed by being divided into a pair of split arms on an extending split surface, and each of the split arms is integrally joined on the split surface.

The work arm having a box-shaped cross section is divided into a pair of split arms, so that the configuration can be simplified and the number of welding points can be reduced in the split state, thereby improving the productivity and strength of the work arm.

In a preferred embodiment, each of the split arms is formed by bending a plate member and positioning each of its bent ends on the split surface.

By joining each of the divided arms obtained by bending the plate member to form a working arm, the number of welding points can be reduced and strength can be imparted, thereby improving the productivity and strength of the working arm.

[0015] In a preferred embodiment, the dividing surface is positioned substantially at the center of the box-shaped section.

[0016] The dividing surface is substantially at the center of the box-shaped cross section, which is a neutral position in terms of strength, to reduce the influence of bending stress on the welded portion and to improve the strength of the working arm.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A working arm structure constructed according to the present invention will be described below in more detail with reference to the accompanying drawings, which show a preferred embodiment of a hydraulic excavator arm as a typical working machine. explain.

Referring to FIG.
A hydraulic excavator indicated by a boom 6 is a boom 6 which is a working arm attached to the body 4 so as to be vertically swingable, and a boom 6
Arm 8 which is a working arm attached to the tip of the robot so as to be vertically swingable. A bucket 10 as a working tool is attached to the tip of the arm 8 so as to be vertically swingable. .

Referring to FIG. 2 together with FIG. 1, the arm 8 is formed in a box-shaped structure by welding various steel members to each other. That is, the arm 8 is formed by joining a pair of divided arms 12 and 14 formed by being divided on a division surface Y extending in the longitudinal direction integrally on the division surface Y, and has a rectangular box-shaped cross section and a box extending in the longitudinal direction. It is formed in a mold structure. The division surface Y is orthogonal to the swing direction of the arm 8 in the hydraulic excavator 2 and is positioned at substantially the center of the box-shaped cross section. A bearing member 16 for swingably connecting the bucket 10 is provided at one longitudinal end of the box-shaped structure, and a bearing member 18 for swingably attaching the boom 6 is provided at the other end. A bearing member 20 for swingably attaching a link member for operating the bucket 10 is attached near the member 16.

Referring to FIGS. 3 and 4 together with FIG. 2, each of the divided arm bodies 12a and 14a of the divided arms 12 and 14 has a plate member having a channel-shaped cross section (U-shape).
It is formed by bending. According to the shape of the arm 8, the size of the channel-shaped cross section is such that the channel-shaped cross section at one end side in the longitudinal direction is large and the channel-shaped cross section at the other end side is small, and these are connected by a straight line. The bent ends of the channel-shaped cross sections of the divided arm bodies 12a and 14a are formed so as to abut each other on the division surface Y, and a rectangular cross section is formed in the abutted state (FIG. 4). An arc-shaped notch 12b for attaching the bearing members 16 and 20 is formed in the split arm body 12a.
And 12c, and a bearing member 16 on the split arm body 14a.
Notches 14b and 1 for mounting
4c and a circular hole 14d for mounting the bearing member 18 are formed on each of a pair of bent sides in the shape of a channel.

Baffle plates 22a and 22b, which are reinforcing plate members, are mounted inside the channel-shaped cross sections of the divided arm bodies 12a and 14a, respectively. The baffle plates 22a and 22b are positioned so as to form the same surface when the divided arm bodies 12a and 14a are integrally welded and joined, and are positioned substantially orthogonal to the longitudinal direction of the arm 8 (FIG. 2). . Each of the baffle plates 22a and 22b is formed in the size of the channel-shaped cross section of the divided arm main bodies 12a and 14a, and is brought into contact with the entire inner surface (three surfaces) of the channel-shaped cross section, and is subjected to deep penetration welding such as laser welding. Are joined.

Each of the bearing members 16, 18, and 20 has a cylindrical shape, and a bearing hole is formed in the axis thereof. The length of the cylinder is such that both end portions thereof have a pair of bent sides of the divided arm bodies 12a and 14a, respectively. Are formed to have a length to be welded to each of them.

The split arms 12 and 1 formed as described above
Reference numeral 4 indicates that each of the bent ends of the divided arm bodies 12a and 14a is in contact with each other on the division plane Y, and is joined by deep and penetration welding such as laser welding. When performing this welding joining, the bearing members 16, 18 and 20 are positioned at predetermined positions and joined to the divided arm main bodies 12a and 14a, respectively. Further, cylinder brackets 24 and 26 are welded to the split arm main bodies 12a and 14a, and plates 12d and 14e are welded and closed to the openings having a large channel-shaped cross section at one end. The opening having the small channel-shaped cross section on the other end side is closed by attaching the bearing member 16.

The operation of the working arm structure of the working machine as described above will be described with reference to FIGS.

(1) Productivity: The arm 8 of the working arm is divided into a pair of split arms 12 and 1 by a split surface Y extending in the longitudinal direction.
4, the plate members are formed by bending a plate member and integrally formed by joining them, so that the number of welding points is greatly reduced. In addition, since the split arms 12 and 14 are formed by bending the plate member, it can be formed of a relatively thin plate, and a welded portion obtained by welding and joining a plurality of plate members to reduce the weight as in the related art is obtained. Many problems are also eliminated. Therefore, the number of welding points is reduced, and productivity is improved.

(2) Strength of working arm: split arms 12 and 14
Is formed by bending the plate member, so that the strength of the working arm can be improved. Baffle plate 22a of reinforcing member
And 22b are securely welded to the entire channel-shaped cross-section, thus eliminating the problem of unbalanced reinforcement of the working arm. In addition, since the joining between the split arm 12 and the split arm 14 is performed at the split surface Y positioned substantially at the center of the strong neutral box-shaped cross section, it is advantageous against bending load.
Further, since the welding line is parallel to the longitudinal load, the fatigue strength of the arm 8 is significantly improved. Further, the problem that the strength of the working arm is impaired by the welded joint because the number of parts to be joined by welding is reduced is also improved. Although the baffle plates 22a and 22b are not welded to each other at the division plane Y, this portion is a neutral portion in strength as described above and has little influence on the strength.

(3) Weight reduction: Since the fatigue strength of the welded joint is improved, the thickness can be reduced.
Work arms can be reduced in weight.

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, and can be variously modified or modified within the scope of the present invention. It is.

(1) Box-shaped cross section: In the embodiment of the present invention, the box-shaped cross section of the working arm is formed in a rectangular shape.
The box-shaped cross section is not limited to a rectangle, and may have an appropriate cross-sectional shape such as a triangle, a polygon, or a circle.

(2) Dividing surface: In the embodiment of the present invention, the dividing surface Y of the pair of divided arms is located at a position where the box-shaped cross section is vertically divided as shown in FIG.
Depending on the direction of the external force applied to the working arm, the structure of the working arm, and the like, the dividing plane is divided into left and right divided arms 13 and 15 by a dividing plane X shown in FIG. 5 in a direction orthogonal to the dividing plane Y in FIG. In the meantime, it can be divided appropriately.

[0031]

According to the working arm structure of the working machine constructed in accordance with the present invention, the welding portion of the working arm formed by welding and joining the plate members to form a box-shaped cross section and extending in the longitudinal direction is reduced, and the weight is reduced. A work arm structure of a work machine, which further improves strength, is provided.

[Brief description of the drawings]

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

FIG. 2 is a perspective view of one of the working arms of the excavator shown in FIG.

FIG. 3 is a perspective view showing the arm shown in FIG. 2 on a pair of split arms together with related members before welding.

FIG. 4 is a sectional view showing a box-shaped section of the arm as viewed in the direction of arrows AA in FIG. 2;

FIG. 5 is a sectional view showing another example of division of the divisional arm when viewed in the direction of arrow AA in FIG. 2;

FIG. 6 is a perspective view of a conventional arm.

FIG. 7 is a sectional view showing a box-shaped section of the arm as viewed in the direction of arrows BB in FIG. 6;

8 is a cross-sectional view of the side plate of the arm as viewed in the direction of arrows CC in FIG. 6;

[Explanation of symbols]

 2: Hydraulic excavator (work machine) 4: Body body 6: Boom (work arm) 8: Arm (work arm) 12: Split arm 12a: Split arm body 14: Split arm 14a: Split arm body 22a: Baffle plate 22b: Baffle plate 50: Arm X: Dividing surface Y: Dividing surface

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masaya Yoto 4-10-1, Yoga, Setagaya-ku, Tokyo Inside New Caterpillar Mitsubishi Corporation (72) Inventor Kunitomo Shimizu 4-1-1, Yoga, Setagaya-ku, Tokyo No. Caterpillar Mitsubishi Corporation (72) Inventor Kazuaki Kinoshita 4-10-1, Yoga, Setagaya-ku, Tokyo (72) Inventor Fumihiro Nishimura 4--10 Yoga, Setagaya-ku, Tokyo No. 1 Inside New Caterpillar Mitsubishi Corporation (72) Inventor Norihisa Manami 4-1-1 Yoga, Setagaya-ku, Tokyo (72) Inventor Morio Murakami 4-chome Yoga, Setagaya-ku, Tokyo No. 10-1 New Caterpillar Mitsubishi Corporation (72) Inventor Yoshiaki Harada 4-10-1, Yoga, Setagaya-ku, Tokyo Pillar Mitsubishi within Co., Ltd.

Claims (3)

[Claims] 1. A work arm formed in a box-shaped cross section by a plate member and extending in a longitudinal direction is formed by dividing a pair of divided arms in a divided surface extending in the longitudinal direction, and each of the divided arms is formed in the divided surface. A work arm structure of a work machine, which is integrally joined. 2. The work arm structure of a work machine according to claim 1, wherein each of said divided arms is formed by bending a plate member and positioning each of its bent ends on said divided surface. 3. The working arm structure for a working machine according to claim 1, wherein the dividing surface is positioned substantially at the center of the box-shaped cross section.