JP2561170Y2 - Structure of swivel frame - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a structure of a turning frame in an upper turning body of a construction machine such as a hydraulic shovel or a working vehicle.

[0002]

2. Description of the Related Art FIG. 3 is a plan view of a main part of a swing frame 1 of an upper swing body for a hydraulic excavator (not shown). In the drawing, reference numeral 2 denotes a lower plate of the revolving frame 1, reference numerals 3 and 4 denote a pair of left and right vertical plates standing on the lower plate 2, reference numeral 5 denotes a counterweight mounting portion, and reference numeral 6 denotes left and right vertical plates 3. A front reinforcing plate provided between the four frames, 7 is a rear reinforcing plate, and 8 and 9 are left and right side frames of the turning frame 1. FIG. 4 is a side view of a main part viewed from AA in FIG. In the figure, 1
Reference numeral 0 denotes a boom foot pin hole. FIG. 5 is a cross-sectional view of FIG.
FIG. 4 is a partially cutaway plan view as seen from a higher position. In the figure, 11,
Numeral 12 denotes protrusions formed on the left and right front portions of the reinforcing plate 7, H and h.
Are the illustrated dimensions of the reinforcing plate 7, respectively. As shown in FIGS. 3 to 5, in the conventional turning frame 1, a pair of left and right vertical plates 3, 4 is erected on the lower surface plate 2, and boots are provided on the upper portions of the vertical plates 3, 4. A muff pin hole 10 is formed, and a counterweight mounting portion 5 is provided at the rear end. Further, reinforcing plates 6 and 7 are inserted and welded to the front and rear portions between the left and right vertical plates 3 and 4, respectively, and projecting portions 11 and 12 are provided at left and right ends of the reinforcing plate 7, respectively.

[0003]

When the excavator performs an excavating operation, a large impact acts on the boom of the work attachment attached to the front of the revolving frame of the upper revolving structure, and the rear end of the excavator performs a large impact. The counterweight also vibrates up and down. Under the influence, excessive stress concentration occurs near the front edge of the reinforcing plate at the welded portion between the left and right vertical plates and the rear reinforcing plate, which may cause a crack. Therefore, in order to disperse the high stress, the reinforcing plate of the prior art was provided with a protruding portion toward the front at each of the left and right ends,
The yield of board material was bad. The purpose of the present invention is to solve the above problems.

[0004]

According to the present invention, there is provided a reinforcing plate having a rectangular shape in plan view at a rear side of a pair of left and right vertical plates erected on a lower surface plate of a revolving frame, between opposed vertical plates. Welded horizontally and welded, and at the front edge of the reinforcing plate, at the position close to the weld with the left and right vertical plates, respectively, formed an arc-shaped concave curved surface portion for stress distribution dispersion .

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a plan view of a main part of a revolving frame 13 (not shown in its entirety) having the structure of the present invention.
In the figure, the same reference numerals are given to components using the same components as the conventional technology. 14 is a bottom plate, 15 and 16 are vertical plates, 17 is a reinforcing plate, and 18 is a concave curved surface portion formed on the reinforcing plate 17. FIG. 2 is a plan view of the reinforcing plate 17.
In the drawing, H indicates the dimension of the reinforcing plate 17 in the front-rear direction.

Next, the structure of the turning frame 13 of the present invention will be described with reference to FIGS. Vertical plate 1 on lower plate 14
5 and 16 are erected, and the reinforcing plate 1 is provided between the vertical plates 15 and 16.
7 are inserted and both ends are welded. At the front edge of the reinforcing plate 17, arcuate concave curved portions 18 are respectively formed at positions close to the welded portions with the left and right vertical plates 15, 16.

Next, the operation of the structure of the turning frame 13 according to the present invention will be described. In the structure of the present invention, arcuate concave curved surface portions 18 for dispersing stress distribution are provided at positions near the welded portions between the left and right vertical plates 15 and 16 at the front edge of the reinforcing plate 17. Thereby, the left and right vertical plates 15, 16
In the left and right corners of the reinforcing plate 17 formed between the first and second concave portions 18, the vertical cross section in the left and right direction is the smallest at the front edge and gradually increases toward the bottom of the concave portion 18. . As described above, the rigidity of the front edge portion at the left and right corners of the reinforcing plate 17 is reduced to make it easier to bend, avoiding the occurrence of stress concentration, and at the same time dispersing the stress distribution along the concave curved surface portion 18, Cracks can be prevented. Thereby, the protrusion 1 of the reinforcing plate 7 of the prior art is
The same action as 1, 12 can be exerted.

[0008]

According to the present invention, the conventional reinforcing plate is provided with projections having the dimension h toward the front at both left and right ends thereof, thereby dispersing the stress of the welded portion and preventing the occurrence of cracks. , The yield of materials was poor and there was much waste.
However, the reinforcing plate of the present invention has the same H dimension as the conventional reinforcing plate, and the purpose can be achieved by forming concave curved portions at positions close to the left and right welds. Therefore, it is possible to save the material of the part h and contribute to resource saving.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part of a revolving frame having the structure of the present invention.

FIG. 2 is a plan view of a reinforcing plate.

FIG. 3 is a plan view of a main part of a swing frame of an upper swing body for a hydraulic excavator.

FIG. 4 is a side view of a main part viewed from AA in FIG. 3;

FIG. 5 is a partially cutaway plan view taken along line BB of FIG. 4;

[Explanation of symbols]

 1,13 Revolving frame 2,14 Lower plate 3,4,15,16 Vertical plate 6,7,17 Reinforcement plate 11,12 Projection 18 Concave curved surface

Claims (1)

(57) [Scope of request for utility model registration] 1. A turning frame of a construction machine in which a pair of left and right vertical plates are erected on a lower surface plate, and a space between the vertical plates is reinforced by a plate material. A rectangular reinforcing plate, which is rectangular in plan view, is horizontally inserted and welded between the facing vertical plates, and at the front edge of the reinforcing plate, at a position close to the welding portion with the left and right vertical plates. A revolving frame structure having a concave curved surface portion for dispersing an arc-shaped stress distribution.