JP2613141B2 - Construction machine swivel frame - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a revolving frame of a construction machine suitable for a construction machine having an upper revolving body such as a hydraulic shovel.

[0002]

2. Description of the Related Art The present applicant has previously described Japanese Patent Publication No. 1-10913.
In Japanese Patent Application Publication (JP-A-58-218527),
A construction machine (working machine) that increases the lateral bending rigidity of the revolving frame was proposed.

FIG. 5 to FIG. 9 show a hydraulic shovel as an example of such a conventional construction machine.

In the drawing, reference numeral 1 denotes a lower traveling body, and 2 denotes an upper revolving body provided on the lower traveling body 1 via a revolving device 3 so as to be revolvable.
And a cab 5, a machine room 6, and a counterweight 7 provided on the revolving frame 4. 8
A working device 8 is provided at the front of the upper revolving unit 2 so as to be able to move up and down. The working device 8 is generally constituted by a boom 9, an arm 10 and a bucket 11.

Next, the revolving frame 4 will be described in detail with reference to FIGS.

[0006] In the figure, reference numeral 12 denotes a turning device 3 on the undercarriage 1.
The center frame 12 is mounted via a turning ring of the turning device 3.
A center plate 13 fixed to A, and a pair of center beams 14, 14 provided on the upper surface side of the center plate 13 so as to be spaced apart left and right and extending in the front-rear direction.
The front side of each center beam 14 is a bracket portion 14A to which the base end side of the boom 9 is pin-coupled. The rear end side of each of the center beams 14 projects rearward from rear overhanging beams 18 and 19, which will be described later, and becomes a counterweight mounting portion 14B.
A counter weight 7 is fixed to 4B via a bolt or the like. Then, each center beam 14 is, as shown in FIG.
Upper flange 15, lower flange 16, and beam plate 1
7 to H-shaped section.

Reference numerals 18 and 19 denote center beams 14 at the base end.
20 and 21 denote front overhanging beams that are fixed to the rear side and overhang to the left and right, and 20 and 21 each have a base end secured to the front side of each center beam 14 and overhang left and right. A plurality of intermediate overhanging beams 22, 2 are provided between the front overhanging beams 20, 21 and the rear overhanging beams 18, 19.
3, 24, 25 are provided, and the intermediate overhanging beams 22 to
Reference numeral 25 denotes a base end side which is fixed to an intermediate portion in the front-rear direction of each center beam 14 by welding.

Reference numerals 26 and 27 denote left overhang beams 18, 2
Projection beams 19, 2 on the tip side and right side of 0, 22, 23
Shown are left and right side frames fixed by welding to the tip sides of 1, 2, 25, respectively. The side frames 26, 27 extend in the front-rear direction in parallel with the respective center beams 14, and the front ends of the side frames 26 are shown. On the side, a substantially L-shaped support member 28 to which the cab 5 is attached is provided between the support member 28 and the front projecting beam 20. As shown in FIG. 9, the side frames 26 and 27 are formed of substantially triangular tubes, and the inner surface thereof has vertical surface portions 26A and 27A facing the beam plate 17 of each center beam 14 on the left and right sides.
It has become.

Reference numeral 29 denotes a rear bottom plate provided on the rear side of each center beam 14 so as to cover the rear bottom surface of the center frame 12. The rear bottom plate 29 is thinner than the lower flange 16 of the center beam 14. It is formed in a substantially rectangular shape by a plate material, and its left and right ends are fixed to the lower flange 16 of each center beam 14 by means of butt welding or the like. The front and rear ends of the rear bottom plate 29 are located on the rear side of the center plate 13, and the intermediate beam 30 fixed between the center beams 14 and the front side of each counterweight mounting portion 14B. It is welded to the rear beam 31 fixed between the center beams 14, respectively. The rear bottom plate 29 is provided with the lower flange 16 of each center beam 14 and the intermediate beam 3.
The periphery of the center frame 12 is formed in a box shape with a bottom by welding the entire periphery to the 0 and the rear beam 31. A punched hole 29A for ventilation is formed in the rear bottom plate 29 in a substantially elliptical shape.

The turning frame 4 of the hydraulic excavator according to the prior art has the above-described configuration, and the boom 9 of the working device 8 is attached to each bracket portion 14A of the center frame 12.
Are pin-connected, and each counterweight mounting part 1 on the rear side is
A counterweight 7 is attached to 4B. A machine room 6 is provided in front of the counterweight 7 on the rear side of each of the center beams 14 and the side frames 26 and 27, and a driver's cab is provided on the front side of the side frames 26 and the support members 28 and the like. 5 are provided.

When turning the upper revolving structure 2 on the lower traveling structure 1 and stopping the revolving operation, a large inertial force is generated by the counterweight 7 which is a heavy object, and each center beam 14 of the revolving frame 4 is turned on. , A left and right lateral bending load acts via the counterweight mounting portion 14B.

Therefore, a rear bottom plate 29 is fixed to the rear side of each center beam 14 between the intermediate beam 30 and the rear beam 31 by full-surface welding, and the rear side of each center beam 14 is formed in a box shape with a bottom. By doing so, the lateral bending rigidity of each center beam 14 is increased, and the lateral bending stress acting on each center beam 14 is reduced.

[0013]

In the above-mentioned prior art, the center beam 14 can be reinforced by the rear bottom plate 29, but the lateral bending load generated by the counterweight 7 when the upper revolving unit 2 stops turning or the like. Also acts on the rear side of the side frames 26, 27, and the side frames 26, 27 and the overhang beams 18, 23, 19, 2
There is a problem that stress concentrates on the welds with No. 5 and these welds are damaged early.

When the rear portions of the side frames 26 and 27 and the counterweight 7 erroneously collide with surrounding obstacles or the like when the upper swing body 2 turns, the side frame 2
The rear portions of the side frames 26, 27 may be deformed as shown by phantom lines in FIG.
There is a problem that stress concentration occurs in the welds between the overhang beams 18, 23, 19, and 25, and these welds are easily damaged.

On the other hand, the applicant of the present application has previously described
In No. 3560, the rear side bottom surface of the revolving frame is closed with an under cover to prevent engine noise in the machine room from leaking to the outside and to prevent external dust and the like from entering the machine room. The proposed revolving frame of construction machinery was proposed. However, in this case, the under cover is merely fixed to each center beam and the rear side of the side frame with bolts, etc., so that the lateral bending load from the counterweight concentrates stress on these bolts. In the worst case, the bolt is broken, and the occurrence of stress concentration at the weld between the side frame and the overhang beam cannot always be effectively prevented.

The present invention has been made in view of the above-mentioned problems of the prior art. In the present invention, the rear portion of a side frame is deformed due to a lateral bending load from a counterweight or the like, and stress concentrates on a welding portion with an overhang beam. It is an object of the present invention to provide a revolving frame of a construction machine, which can prevent dripping and can greatly improve the overall strength, lateral bending rigidity and the like.

[0017]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention employs a feature that a left and right sides of a rear bottom plate are provided between each center beam of a center frame and each side frame. And left and right reinforcing plates for covering the rear bottom surface between the side frames are provided, and each of the reinforcing plates is welded at both front and rear ends thereof to the intermediate intermediate overhanging beam and the rear overhanging beam of the intermediate overhanging beams. The left and right ends are welded to the center beams and the side frames.

[0018]

With the above construction, the left and right reinforcing plates can be entirely welded to each center beam, each side frame, the rear side and rear intermediate side extension beams and each rear extension beam, and each side frame and each extension. It is possible to prevent the stress concentration from occurring at the welding portion with the beam and the like by the respective reinforcing plates.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the embodiment, the same components as those of the prior art shown in FIGS. 5 to 9 are denoted by the same reference numerals, and description thereof will be omitted.

In the drawing, reference numerals 41 and 42 are located on the left and right sides of the rear bottom plate 29 of the center frame 12, respectively, and the rear side of each center beam 14 and the side frames 26 and 27.
5 shows left and right reinforcing plates provided between the rear bottom plate 29 and the rear bottom plate 29.
Similarly, for example, the lower flange 16 of the center beam 14
Each is formed in a substantially rectangular shape by a thinner plate material. The reinforcing plate 41 has its left and right ends fixed to the lower end of the vertical surface 26A of the side frame 26 and the lower flange 16 of the center beam 14 by means of butt welding, as shown in FIG. Are welded to the rear intermediate projecting beam 23 and the rear projecting beam 18 on the rear side of the intermediate projecting beams 22 and 23 as shown in FIG.

The reinforcing plate 42 on the right side is
As shown in FIG. 4, the right ends are fixed to the lower flange 16 of the center beam 14 and the lower end of the vertical surface 27A of the side frame 27 by means of butt welding, respectively, and the front and rear ends are intermediate as shown in FIG. Overhang beam 24,
25 are welded to the rear overhanging beam 25 and the rear overhanging beam 19, respectively. The periphery of the reinforcing plates 41 and 42 has a lower flange 16 of each center beam 14, side frames 26 and 27, intermediate overhanging beams 23 and 25, and rear overhanging beams 18 and 1.
9, the side frames 26,
The rear side between the center beam 27 and each center beam 14 is formed in a box shape with a bottom. In addition, punching holes 41A and 42A for ventilation are formed in the reinforcing plates 41 and 42 in a substantially oval shape.

The turning frame 4 of the hydraulic shovel according to the present embodiment has the above-described configuration, and its basic operation is not particularly different from that of the prior art.

However, in this embodiment, the reinforcing plates 41 and 42 that cover the rear bottom surface of the revolving frame 4 together with the rear bottom plate 29 are disposed on both the left and right sides of the rear bottom plate 29. Surrounding the lower flange 16 of each center beam 14, side frames 26 and 27
Lower end of vertical surface portions 26A and 27A, intermediate overhang beam 2
3 and 25 and the lower ends of the rear overhanging beams 18 and 19 are entirely welded.
6, 27 etc. can be effectively reinforced,
27 can be greatly improved in lateral bending rigidity.

Therefore, according to this embodiment, the upper revolving unit 2
Even if the lateral bending load from the counterweight 7 acts on the side frames 26 and 27 when the vehicle turns or stops, the load is applied to the reinforcing plates 41 and 42 and the intermediate overhang beam 2.
3, 25, the rear overhanging beams 18, 19 can be dispersed and received, and the side frames 26, 27 and the overhanging beam 1 can be received.
It is possible to reliably prevent the occurrence of stress concentration at the welded portions with 8, 19, 23 and 25. Then, as described in the related art, the deformation of the side frames 26 and 27 as shown by the imaginary line in FIG. 6 can be restricted, and the problem that the welded portion is damaged early can be solved.

Further, since the rear bottom surface of the revolving frame 4 is almost completely covered by the reinforcing plates 41 and 42 and the rear bottom plate 29, a reinforcing bar or the like is pushed up from below during excavation work at the site. Also, the engine, the hydraulic pump, the hydraulic piping (all not shown) and the like in the machine room 6 can be protected by the reinforcing plates 41 and 42 and the rear bottom plate 29, and the reliability can be improved.

In the above-described embodiment, the description has been made by taking the hydraulic excavator as an example. However, the present invention is not limited to this, and can be applied to various construction machines having an upper rotating body such as a hydraulic crane.

[0027]

As described in detail above, according to the present invention, left and right reinforcing plates are provided on both the left and right sides of the rear bottom plate and cover the rear bottom surface between the side frames. Is welded to each center beam of the center frame, each side frame, the intermediate overhanging beam on the rear side and each rear overhanging beam, so that the welds with each side frame and each intermediate overhanging beam can be effectively reinforced, Various effects such as increased rigidity against lateral bending load from the counterweight when the upper revolving structure turns or stop turning, etc., and can reduce stress concentration etc. in the welded part and improve durability and reliability. To play.

[Brief description of the drawings]

FIG. 1 is a plan view showing a turning frame according to an embodiment of the present invention.

FIG. 2 is a sectional view taken in the direction of arrows II-II in FIG.

FIG. 3 is an enlarged sectional view taken in the direction of arrows III-III in FIG.

FIG. 4 is an enlarged sectional view taken in the direction of arrows IV-IV in FIG.

FIG. 5 is an overall view showing a conventional hydraulic excavator.

FIG. 6 is an enlarged plan view of the turning frame shown in FIG. 5;

FIG. 7 is a sectional view taken in the direction of arrows VII-VII in FIG. 6;

FIG. 8 is an enlarged sectional view taken in the direction of arrows VIII-VIII in FIG.

9 is an enlarged cross-sectional view in the direction of arrows IX-IX in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower traveling body 2 Upper revolving superstructure 3 Revolving device 4 Revolving frame 12 Center frame 13 Center plate 14 Center beam 14B Counter weight mounting part 18, 19 Rear overhanging beam 20, 21 Front overhanging beam 22, 23, 24, 25 Intermediate overhang Beam 26, 27 Side frame 29 Rear bottom plate 41, 42 Reinforcement plate

Claims (1)

(57) [Claims] 1. A center frame having a pair of center beams separated to the left and right and extending in the front-rear direction, and a rear end side of each center beam serving as a counterweight mounting portion, and each center frame of the center frame. A front overhanging beam, a rear overhanging beam, and a plurality of intermediate overhanging beams respectively extending from the beam to the left and right; a left and right side frame fixed to the tip of each overhanging beam and extending in the front-rear direction; And a rear bottom plate fixed between the center beams of the center frame so as to cover a rear bottom surface of the center frame. The left and right sides of the rear bottom plate are located between the center beam and each side frame. Left and right reinforcing plates are provided to cover the bottom surface, and each of the reinforcing plates is welded at the front and rear ends thereof to the rear intermediate overhanging beam and each rear overhanging beam of the intermediate overhanging beams, and the left and right ends thereof are formed as described above. A turning frame for a construction machine, wherein the center beam and each side frame are welded to each other.