JP2001342646A - Turning frame of construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase join strength between a bracket part of a center frame and an overhang beam for supporting cab using a reinforcing member and reduce stress concentration in a welded section. SOLUTION: A turning frame 41 consists of the center frame 12, a side frame 19 on the left side joined with the center frame 12 through the overhang beams 21, 22, and a side frame 20 on the right side joined with the center frame 12 through the overhang beams 28 to 31. A reinforcing plate 42 is provided and positioned between a vertical beam part 26 of a cab support frame 24 and a boom bracket 15A in an end part of the overhang beam 21. This reinforcing plate 42 is joined with an outer face of the boom bracket 15A and an upper side angle corner of the overhang beam 21 by welding it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turning frame of a construction machine suitable for use in a construction machine such as a hydraulic shovel.

[0002]

2. Description of the Related Art Generally, a construction machine such as a hydraulic shovel is provided with a swing frame on a lower traveling body so as to be swingable, and a building cover for accommodating a cab, a prime mover, etc. A configuration is provided in which a counter weight and the like are provided (for example, Japanese Patent Laid-Open No. 5-1433).

[0003] Fig. 9 shows a case in which this kind of conventional revolving frame of a construction machine is applied to a hydraulic excavator.
This will be described with reference to FIG.

In FIG. 1, reference numeral 1 denotes a lower traveling body of a hydraulic shovel, and 2 denotes an upper revolving body which is rotatably mounted on the lower traveling body 1. The upper revolving body 2 includes a revolving frame 11 which will be described later.
A cab 3 mounted on the front left side of the revolving frame 11 to define a driver's cab; and a motive motor and a hydraulic pump (FIG. (Not shown) and the like, and a counterweight 5 and the like, which is provided on the revolving frame 11 at the rear side of the building cover 4 and balances the weight of the working device 6 described later. .

A working device 6 is provided at the front of the upper revolving unit 2 so as to be able to move up and down. The working device 6 has a base end connected to boom brackets 14A and 15A, which will be described later, with a pair of left and right booms. A boom 7 which is raised and lowered by a cylinder 7A (only one of which is shown), an arm 8 which is pin-connected to a tip end of the boom 7 and which is raised and lowered by an arm cylinder 8A;
A pin cylinder is connected to a tip end of the arm 8 by a bucket cylinder 9.
A bucket 9 as a working tool rotated by A performs excavation work of earth and sand with the bucket 9.

Reference numeral 11 denotes a revolving frame which constitutes a frame of the upper revolving unit 2. The revolving frame 11 has a structure shown in FIGS.
1, a center frame 12 and a tail frame 17 which will be described later and are located at the center and extend forward and rearward;
Lateral side frames 1 located on these left and right sides
9, 20, and the like.

Reference numeral 12 denotes a center frame which forms a central portion of the revolving frame 11. The center frame 12 includes a bottom plate 13 formed of a thick steel plate or the like in a flat plate shape, and
Left and right vertical plates 14 and 15 which are erected on the upper surface side of the base plate 3 using welding means and extend in the front and rear directions with lengths substantially corresponding to the bottom plate 13 and horizontal plates 16 and the like described later. It is configured.

The front sides of these vertical plates 14 and 15 are provided with left and right boom brackets 14 as brackets to which the boom 7 of the working device 6 is pin-connected so as to be able to move up and down.
A and 15A. Also, the boom bracket 14
The left and right cylinder brackets 14B, 15B are located on the front end side of A, 15A on the front side of a horizontal plate 16 described later.
FIG. 9 shows the cylinder brackets 14B and 15B.
The base end side of the boom cylinder 7A shown in FIG.

Reference numeral 16 denotes a reinforcing horizontal plate provided between the boom brackets 14A and 15A and provided on the center frame 12. The horizontal plate 16 is provided on the left side of the boom brackets 14A and 15A in order to increase the bending strength and the like. , Right ends are welded to the boom brackets 14A, 15A.

Here, the horizontal plate 16 is formed by bending a flat plate material such as a steel plate into a substantially rectangular shape as shown by a dotted line in FIG. It comprises an extended vertical plate portion 16A and an inclined plate portion 16B extending obliquely upward and rearward between the boom brackets 14A and 15A from the upper end side of the vertical plate portion 16A. The horizontal plate 16 is formed with a substantially square opening 16C as shown in FIG.

Reference numeral 17 denotes a tail frame provided on the rear end side of the center frame 12. The tail frame 17 is integrated with the bottom plate 13 and the left and right vertical plates 14 and 15 of the center frame 12 by means such as welding. It is something that has been. The vertical plate 1 is located on the rear end side of the tail frame 17.
4 and 15 are extended rearward, and the left and right weight attachment portions 18 having an I-shaped cross section (I flange structure) are formed.
A, 18B are provided.

The weight mounting portions 18A, 18B
In this state, the counterweight 5 shown in FIG. 9 is placed from above, and in this state, the counterweight 5 is detachably attached to the weight attachment portions 18A and 18B using bolts (not shown) or the like. is there.

Reference numerals 19 and 20 denote left and right side frames constituting the turning frame 11 together with the center frame 12, respectively.
The left and right side frames 19 and 20 are, for example, a section D
It is formed using a D-shaped frame having a U-shape, and extends forward and backward on both the left and right sides of the revolving frame 11 as shown in FIG.

Reference numeral 21 denotes an overhanging beam for supporting the cab provided between the left side frame 19 and the center frame 12. The overhanging beam 21 has a left end joined to the side frame 19 by welding and a right end. The end is joined to the left boom bracket 14A by welding, and the lower end is welded to the upper surface of the bottom plate 13.

The overhanging beam 21 is made of a beam having a U-shaped cross section as shown in FIG.
A, 21B and an upper plate portion 21C connecting the side plate portions 21A, 21B. Further, the overhang beam 21 is provided on the vertical plate portion 16A of the horizontal plate 16 as shown in FIG.
The side plate 21A is disposed at an offset position shifted rearward by the dimension a, and the dimension a is set to a different size depending on the type of the excavator.

Reference numeral 22 denotes another overhanging beam provided between the left side frame 19 and the center frame 12.
The overhanging beam 22 is also made of a beam member having a U-shaped cross section as shown in FIG. The overhanging beam 22 is also joined at its left end to the side frame 19 and at its right end to the left vertical plate 14 and the bottom plate 13 by welding.

The overhanging beam 22 is disposed at a position substantially corresponding to the rear end of the cab 3 shown in FIG. 9, and supports the rear end of the cab 3 from below through a mounting mount 27 and the like which will be described later. Configuration.

Reference numeral 23 denotes a rear plate provided between the rear end of the side frame 19 and the tail frame 17. The rear plate 23 connects the weight mounting portion 18A of the tail frame 17 to the side frame 19. .

Reference numeral 24 denotes a cab support frame provided between the front end of the side frame 19 and the overhang beam 21. The cab support frame 24 is located in front of the overhang beam 21 as shown in FIG. A cross beam 25 joined to the front end of the boom bracket 21 and extending parallel to the overhang beam 21; a front end joined to the cross beam 25;
A is formed by a vertical beam portion 26 extending in parallel with A and joined to the bottom plate 13 and the overhanging beam 21 by welding.

The horizontal beam portion 25 and the vertical beam portion 26 of the cab support frame 24 serve as a cab support for supporting the cab 3 shown in FIG. Make up. Further, a gap having a dimension b shown in FIG. 10 is formed between the vertical beam portion 26 of the cab support frame 24 and the boom bracket 14A, and the gap having the dimension b is such that the boom 7 shown in FIG. This is to prevent contact with the side surface.

Reference numerals 27, 27,... Denote mounting mounts for the cab 3. The mounting mounts 27 are provided on the cab support frame 24 and the overhang beams 21, 22, respectively.

Reference numerals 28, 29, 30, 31 denote right overhanging beams provided between the right side frame 20 and the center frame 12, and the overhanging beams 28, 29, 3
0, 31 are spaced apart front and rear, and the rear plate 3
2, the side frame 20 is connected to the center frame 12 and the tail frame 17.

The hydraulic excavator according to the prior art has the above-described configuration, and its operation will be described below.

First, when the vehicle travels at the work site, the vehicle is moved forward or backward by driving a traveling motor (not shown) of the lower traveling body 1. When excavation work such as earth and sand is performed, the upper swing body 2 is swiveled to dispose the working device 6 in an arbitrary direction. In this state, the boom 7 and the arm 8 are raised and lowered, and the bucket 9 is moved. The excavation work is performed by rotating.

[0025]

In the above-described swivel frame 11 according to the prior art, an overhanging beam 21 for supporting the cab 3 for supporting the cab 3 from below is provided between the side frame 19 and the center frame 12. And the end of the overhang beam 21 is attached to the left boom bracket 14.
A and the bottom plate 13 are joined by welding.

However, lateral bending stress is applied to the boom brackets 14A and 15A of the center frame 12 through the boom 7 due to a lateral load or the like applied to the working device 6 from the outside. There is a problem that stress concentration is likely to occur at a welding location between the boom bracket 14A and the left boom bracket 14A.

In this case, the right overhanging beams 28, 29
And the like are provided between the center frame 12 and the side frames 20 and support the storage box for tools and the like from below, so that the load is light, and the welding point between the right boom bracket 15A and the overhang beam 29 is provided. Are hardly affected by stress concentration.

However, since the cab supporting overhanging beam 21 located on the left side of the center frame 12 supports the heavy cab 3 from below, the end of the overhanging beam 21 is welded to the left boom bracket 14A. The parts are easily affected by stress concentration, and it is difficult to increase the durability and life of the welded parts.

In general, the cab 3 is used as a common part, whereas the boom brackets 14A, 15A and the horizontal plate 16 of the center frame 12 have different dimensions from the center of rotation, etc., depending on the type of hydraulic excavator. Therefore, as shown in FIG.
The overhang beam 21 has to be disposed at an offset position shifted from the vertical plate portion 16A of the horizontal plate 16.

The welded portion between the end of the overhanging beam 21 and the left boom bracket 14A becomes more susceptible to stress concentration as the offset amount (position shift amount) of the dimension a becomes larger. , The durability and life will be reduced.

For this reason, when welding the end of the overhang beam 21 to the boom bracket 14A, measures are taken such as increasing the number of welding beats and increasing the welding leg length.
In fact, it is not always an effective means for alleviating stress concentration.

12 and 13, another reinforcing rib 35 is additionally provided between the end of the overhanging beam 21 and the left boom bracket 14A. Thus, the welding portion between the overhang beam 21 and the boom bracket 14A is reinforced.

However, in this case, the reinforcing rib 35 is made of a substantially triangular plate, and the side plate 21A of the overhang beam 21 is formed.
It is merely provided by using welding means so as to extend obliquely upward from a corner portion located between the upper plate portion 21C and the welding portion side of the horizontal plate 16 with respect to the boom bracket 14A. .

As shown in FIG. 12, since the reinforcing ribs 35 are arranged in a small gap having a small size b, it is necessary to sufficiently reinforce the welding portion between the overhang beam 21 and the boom bracket 14A. However, it is difficult to use it alone, and it cannot be an effective measure for alleviating stress concentration, and there is a problem that the durability and life of the welded portion cannot be sufficiently increased.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a reinforcing member for compensating for a positional shift between a horizontal plate of a center frame and an overhanging beam for supporting a cab. As a result, the joint strength between the bracket portion of the center frame and the overhanging beam is increased, stress concentration can be reduced at the welded portions of the two, and the durability and life of the welded portion can be improved. An object of the present invention is to provide a swing frame of a construction machine.

[0036]

In order to solve the above-mentioned problems, the present invention provides a bottom plate, a pair of left and right vertical plates which are erected on the bottom plate and whose front side is a bracket for a working device. And a center frame consisting of a horizontal plate joined between the bracket portions of the vertical plates and reinforcing the bracket portions, and one end is joined to the bottom plate of the center frame and the bracket portion of the vertical plate, and The present invention is applied to a revolving frame of a construction machine having an end portion joined to a side frame and an extension beam for supporting the cab together with the side frame for supporting the cab from below.

The feature of the structure adopted in the first aspect of the present invention is that the joining position between the bracket portion of each of the vertical plates and the overhanging beam compensates for the positional deviation between the horizontal plate and the overhanging beam. A reinforcing member, the reinforcing member having a side surface joined to the bracket part along the horizontal plate, a lower end side joined to the bottom plate, and an upper end side joined to the overhanging beam. .

With such a configuration, the reinforcing member can be provided so as to be attached to the horizontal plate, and the displacement between the horizontal plate and the overhang beam can be compensated. Then, in a state where the bracket for the working device is sandwiched between the left and right sides by the horizontal plate and the reinforcing member, the joining strength between the overhanging beam and the bracket can be increased, and stress concentration can be reduced.

According to the second aspect of the present invention, the reinforcing member is located on the front side of the overhanging beam by a dimension corresponding to the horizontal plate, and rises upward from the upper surface of the bottom plate. An upper plate portion is bent rearward from the upper end of the front plate portion toward the overhanging beam and has a rear end joined to the overhanging beam.

Thus, the front plate portion of the reinforcing member can be disposed so as to rise upward from the upper surface of the bottom plate along the horizontal plate,
By joining the rear end side of the upper plate portion to the overhang beam, the strength of the entire welded portion can be increased.

According to a third aspect of the present invention, there is provided a cross beam portion between the overhang beam and the side frame, which is located in front of the overhang beam and is joined to the front end of the side frame and extends in parallel with the overhang beam. And a substantially L-shaped cab support frame comprising a front end side joined to the cross beam portion, a rear end side extending parallel to the bracket portion and a bottom plate and a vertical beam portion joined to the overhanging beam. And the bracket portion is joined to the rear end side of the portion.

Thus, the reinforcing member is disposed between the vertical beam portion and the bracket portion of the cab support frame, and the left and right sides thereof can be joined to the vertical beam portion and the bracket portion, and the gap between the two can be provided. Can be filled with a reinforcing member.

Further, according to the invention of claim 4, the reinforcing member is made of a plate material bent substantially in an L-shape, the front end of which is the bottom plate, the rear end is the overhanging beam, and the left end is the bracket. The right end is joined to the vertical beam portion to define a closed space inside.

Accordingly, a reinforcing member made of a plate material bent substantially in an L shape is provided between the bottom plate, the overhang beam, the bracket portion and the vertical beam portion, and a closed space can be defined therebetween. The strength of the weld can be increased.

[0045]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a construction machine according to an embodiment of the present invention; FIG. In the present embodiment, the same components as those of the prior art shown in FIGS. 9 to 11 are denoted by the same reference numerals, and description thereof will be omitted.

Here, FIG. 1 to FIG. 6 show a first embodiment of the present invention. In the figure, reference numeral 41 denotes a revolving frame according to the present embodiment. The revolving frame 41 has a center frame 1 like the revolving frame 11 described in the related art.
2, a tail frame 17 and left and right side frames 19, 20 and the like.
3. Left and right vertical plates 14, 15 and boom bracket 1
It is constituted by a horizontal plate 16 or the like that reinforces the space between 4A and 15A from the inside.

An overhanging beam 21 for supporting the cab is joined to the boom bracket 14A at the right end, and the overhanging beam 21 is joined to the side frame 19 at the left end. Also, the cab support frame 24 is
The rear end side extends parallel to the boom bracket 14A and is joined to the bottom plate 13 and the overhang beam 21, and a gap having a dimension b shown in FIG. 1 is formed between the vertical beam portion 26 and the boom bracket 14A. .

However, the revolving frame 41 employed in the present embodiment is located between the vertical beam portion 26 and the boom bracket 14A and is provided at the end of the overhanging beam 21 with a reinforcing plate 4 to be described later.
2 is provided, and the boom bracket 1 is
It is configured to increase the bonding strength between 4A and the overhang beam 21.

Reference numeral 42 denotes a reinforcing plate as a reinforcing member employed in the present embodiment. The reinforcing plate 42 is formed by bending a flat plate such as a steel plate into an L shape as shown in FIGS. , Its width dimension W corresponds to the gap of dimension b shown in FIG. The reinforcing plate 42 has a front plate 42A that rises upward to be substantially perpendicular to the bottom plate 13, and
An upper plate portion 42B is bent in an L shape from the upper end of the front plate portion 42A to the rear side, and extends substantially parallel to the bottom plate 13.

Here, as shown in FIGS. 1 and 2, the reinforcing plate 42 is disposed so as to fill a gap of dimension b between the vertical beam portion 26 of the cab support frame 24 and the boom bracket 14A.
The left and right sides are welded to the outer surface of the boom bracket 14A and the vertical beam portion 26.

As shown in FIG. 5, the reinforcing plate 42 has the lower end of the front plate 42A joined to the upper surface of the bottom plate 13 by welding, and the rear end of the upper plate 42B is connected to the side plate 21A of the overhang beam 21. It is joined by welding to a corner located between the upper plate 21C. The reinforcing plate 42 defines a closed space S between the reinforcing plate 42 and the side plate 21A of the overhang beam 21 as shown in FIG.

Further, the front plate portion 42A of the reinforcing plate 42 is separated from the side plate portion 21A of the overhanging beam 21 by a distance a to the front side and is directed upward along the vertical plate portion 16A of the horizontal plate 16. It is arranged to stand up. Thereby, the reinforcing plate 42 is connected to the boom bracket 1 with the horizontal plate 16.
4A is sandwiched from both the left and right sides, and the boom bracket 14A is prevented from being bent and deformed left and right by a lateral load from the outside.

The turning frame 41 of the hydraulic shovel according to the present embodiment has the above-described configuration, and its basic operation and the like are not particularly different from those of the prior art.

However, according to the present embodiment, the reinforcing plate 42 is provided between the vertical beam 26 of the cab support frame 24 and the boom bracket 14A at the end of the overhanging beam 21. Is welded to the outer surface of the boom bracket 14A and the upper corner of the overhanging beam 21 by welding, so that the following operation and effect can be obtained.

That is, in the manufacturing process of the revolving frame 41, as shown in FIGS.
Tail frame 17, left and right side frames 19, 2
0 etc. are manufactured by welding on separate production lines. The left and right vertical plates 14 and 15 are welded on the bottom plate 13 of the center frame 12, and the horizontal plate 16 and the like are assembled by welding between the left and right boom brackets 14A and 15A.

The overhanging beams 21, 22, the rear plate 23, the cab support frame 24, and the like are joined to the left side frame 19 by welding. on the other hand,
The right side frame 20 has overhanging beams 28 to 3.
1. The rear plate 23 and the like are respectively joined by welding.

A reinforcing plate 42 is fixed in advance to the longitudinal beam 26 of the cab support frame 24 and the end of the overhanging beam 21 by welding. In this case, the reinforcing plate 42 is formed by bending a flat plate material such as a steel plate into an L-shape, and its width dimension W corresponds to the gap of the dimension b shown in FIG. 1, so that it faces the boom bracket 14A. The side surface of the reinforcing plate 42 is disposed so as to be flush with the end surface of the overhang beam 21.

In the final assembling process of the revolving frame 41, the tail frame 17 is attached to the center frame 12 as shown by arrows in FIGS. 22,2
8 to 31 and the like, and fillet welding or the like is applied to each joint portion.

At this time, the reinforcing plate 42 is disposed so as to fill a gap between the vertical beam portion 26 of the cab support frame 24 and the boom bracket 14A (a gap having a dimension b shown in FIG. 1). The right side portions are joined to the outer surface of the boom bracket 14A and the vertical beam portion 26. The lower end of the front plate 42A of the reinforcing plate 42 is joined to the upper surface of the bottom plate 13, and the upper plate 4
The rear end of 2B is joined to the corner of the overhang beam 21 between the side plate 21A and the upper plate 21C.

Thus, according to the present embodiment, the reinforcing plate 42 is provided between the vertical beam 26 of the cab support frame 24 and the boom bracket 14A at the end of the overhanging beam 21. Are welded to the outer surface of the boom bracket 14A and the upper corners of the overhang beam 21 and the like. Then, the front plate portion 42A of the reinforcing plate 42
Is disposed on the front side of the side plate portion 21A of the overhang beam 21 by the dimension a, and is disposed so as to rise upward along the vertical plate portion 16A of the horizontal plate 16.

As a result, the boom bracket 14A can be sandwiched between the reinforcing plate 42 and the horizontal plate 16 from both the left and right sides, and the boom bracket 14A is bent left and right by an external lateral load or the like. Deformation can be suppressed.

As shown in FIG. 5, the vertical plate 16A of the horizontal plate 16 and the side plate 21A of the overhang beam 21 have a dimension a.
The dimension “a” differs depending on the type of the excavator or the like.

Therefore, in this case, a plurality of types of reinforcing plates 42 having different lengths such as the upper plate portion 42B are prepared in advance, and the front plate portion 42A of the reinforcing plate 42 is set to have a dimension a with respect to the overhang beam 21. By disposing them only on the front side, the displacement between them can be compensated for by the reinforcing plate 42, and it is possible to easily cope with a plurality of types of hydraulic excavators, and to suppress the bending stress acting on the boom bracket 14A to a small value. it can.

Therefore, according to this embodiment, the reinforcing plate 42 is additionally provided at the end of the overhanging beam 21 between the vertical beam 26 of the cab support frame 24 and the boom bracket 14A. It is possible to compensate for the positional displacement between the vertical plate portion 16A of the horizontal plate 16 and the side plate portion 21A of the overhanging beam 21, and to reduce the joint strength between the boom bracket 14A of the center frame 12 and the overhanging beam 21 for cab support. Can be enhanced.

Further, the occurrence of stress concentration at the welding portion between the boom bracket 14A and the overhanging beam 21 can be surely alleviated, and the durability, service life, and the like at these welding portions can be greatly improved.

Further, the reinforcing plate 42 can be disposed so as to fill a small gap (a gap having a dimension b shown in FIG. 1) between the vertical beam portion 26 of the cab support frame 24 and the boom bracket 14A. Effective countermeasures against the stress concentration of the above.

Next, FIG. 7 shows a second embodiment of the present invention. The feature of the present embodiment is that a reinforcing plate 51 as a reinforcing member is formed of a plate material such as a steel plate obtained by bending a reinforcing plate 51 into a U-shape. I did it.

The reinforcing plate 51 has substantially the same structure as the reinforcing plate 42 described in the first embodiment, and has a front plate 51A and an upper plate 51B.
On the rear end side of B, a rear plate portion 51C extending downward in parallel with the front plate portion 51A is integrally formed.

Further, the rear plate portion 51C of the reinforcing plate 51 is provided as shown in FIG.
And is provided so as to abut against the side plate portion 21A of the overhang beam 21 illustrated in FIG. The reinforcing plate 51 is joined by welding at the corner between the upper plate 51B and the rear plate 51C to the corner between the side plate 21A of the overhang beam 21 and the upper plate 21C. The lower end of the rear plate portion 51C is
For example, it is joined to the upper surface of the bottom plate 13 by welding.

Thus, in the present embodiment configured as described above, substantially the same operation and effect as in the first embodiment can be obtained.

Next, FIG. 8 shows a third embodiment of the present invention. The feature of this embodiment is that a reinforcing plate 61 as a reinforcing member includes a front plate portion 61A and a front plate portion 61A. The upper plate portion 61B is formed by largely curving the upper side.

Here, the reinforcing plate 61 has substantially the same configuration as the reinforcing plate 42 described in the first embodiment, but smoothly curves between the front plate portion 61A and the upper plate portion 61B. They are different in that they do.

Thus, also in the present embodiment having such a configuration, it is possible to obtain substantially the same operation and effect as in the first embodiment.

In each of the above embodiments, a hydraulic excavator has been described as an example of a construction machine. However, the present invention is not limited to this. For example, an upper revolving unit such as a wheel type hydraulic excavator or a hydraulic crane may be used. The present invention may be applied to a revolving frame of a construction machine including

[0075]

As described above in detail, according to the first aspect of the present invention, the misalignment between the horizontal plate and the overhanging beam is provided at the joint between the overhanging beam for supporting the cab and the bracket for the working device. Provision of a reinforcing member for supplementing, joining the side surface of the reinforcing member to the bracket portion along the horizontal plate,
Since the lower end is joined to the bottom plate and the upper end is joined to the overhang beam, the bracket is sandwiched between the left and right sides by the horizontal plate and the reinforcing member. It can be joined to the bracket part so as to be attached, and the joining strength between the bracket part and the overhang beam can be increased. Further, it is possible to effectively reduce the occurrence of stress concentration at both welding portions, and it is possible to greatly extend the durability and the life of the welding portions.

According to the second aspect of the present invention, the reinforcing member includes a front plate portion separated from the overhang beam by a dimension corresponding to the horizontal plate to the front side, and the overhang beam from the upper end of the front plate portion. Since the rear end is bent toward the rear side and the rear end is constituted by the upper plate portion joined to the overhanging beam,
The front plate portion of the reinforcing member can be disposed so as to rise upward from the upper surface of the bottom plate along the horizontal plate, and the rear end side of the upper plate portion can be joined to the overhang beam to increase the strength of the entire welded portion. .

According to a third aspect of the present invention, a cab support frame having a substantially L-shape formed by a horizontal beam and a vertical beam is provided between an overhanging beam for supporting a cab and a side frame, and a reinforcing member is provided. Is connected to the rear end of the vertical beam and the bracket, respectively. Therefore, a reinforcing member is disposed between the vertical beam and the bracket of the cab support frame, and the left and right sides are vertically Can be joined to the beam and bracket,
The gap between the two can be filled with a reinforcing member to increase the welding strength of the cab support frame. In addition, the reinforcing member can be provided so as to fill a small gap between the vertical beam portion and the bracket portion of the cab support frame, and effective countermeasures against stress concentration on the welded portion can be taken.

Further, according to the invention described in claim 4,
The reinforcing member is made of a plate material bent in a substantially L-shape, and the front, rear, left and right ends are respectively joined to a bottom plate, an overhang beam, a bracket portion, and a vertical beam portion, so that a closed space is formed therein. Therefore, a reinforcing member made of a plate material bent substantially in an L shape is provided between the bottom plate, the overhang beam, the bracket portion, and the vertical beam portion, and a closed space can be defined therebetween. Thus, the strength of each welding portion can be reliably increased.

[Brief description of the drawings]

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

FIG. 2 is a perspective view of the turning frame shown in FIG.

FIG. 3 is an exploded perspective view of the turning frame shown in FIG. 2;

FIG. 4 is an exploded perspective view of the revolving frame as viewed from a side opposite to FIG. 3;

5 is a cross-sectional view of a bottom plate, a boom bracket, an overhang beam, a reinforcing plate, and the like of the revolving frame as viewed from the direction of arrows VV in FIG.

FIG. 6 is an enlarged perspective view showing a reinforcing plate in FIG. 5;

FIG. 7 is a perspective view showing a reinforcing plate employed in the second embodiment.

FIG. 8 is a perspective view showing a reinforcing plate employed in the third embodiment.

FIG. 9 is an overall view showing a hydraulic excavator to which a turning frame according to the related art is applied.

FIG. 10 is a plan view showing the turning frame in FIG. 9 as a single body.

11 is a cross-sectional view of a bottom plate, a boom bracket, an overhang beam, and the like of the revolving frame as viewed in a direction indicated by arrows XI-XI in FIG.

FIG. 12 is a plan view showing a turning frame according to another related art.

FIG. 13 shows a bottom plate, a boom bracket, an overhang beam, a reinforcing rib and the like of the revolving frame by arrows XIII-XI in FIG.
It is sectional drawing seen from the II direction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower traveling body 2 Upper revolving superstructure 3 Cab 6 Work device 7 Boom 12 Center frame 13 Bottom plate 14, 15 Vertical plate 14A, 15A Boom bracket (bracket part) 16 Horizontal plate 17 Tail frame 19, 20 Side frame 21 For cab support Overhang beam 24 Cab support frame 25 Horizontal beam part 26 Vertical beam part 41 Revolving frame 42, 51, 61 Reinforcement plate (reinforcement member) 42A, 51A, 61A Front plate part 42B, 51B, 61B Upper plate part S Closed space

Claims (4)

[Claims] 1. A bottom plate, a pair of left and right vertical plates erected on the bottom plate and having a front portion serving as a bracket for a working device, and joined between the brackets of the respective vertical plates. A center frame consisting of a horizontal plate to be reinforced, and one end is joined to the bottom plate of the center frame and the bracket of the vertical plate, and the other end is joined to the side frame, and the cab together with the side frame is moved from below. In a revolving frame of a construction machine comprising a cab supporting overhanging beam for supporting, the joint between the bracket portion of each of the vertical plates and the overhanging beam has a positional shift between the horizontal plate and the overhanging beam. A reinforcing member for supplementing the reinforcing member, the reinforcing member is joined to the bracket portion along a side surface along the horizontal plate, a lower end is joined to the bottom plate, and an upper end is joined to the overhanging beam; Construction machine of the revolving frame, characterized in that was. 2. The front plate portion, which is spaced apart from the overhanging beam by a dimension corresponding to the horizontal plate toward the front side and rises upward from the upper surface of the bottom plate, The revolving frame of a construction machine according to claim 1, wherein an upper plate portion is bent rearward from an upper end toward the overhanging beam and has a rear end joined to the overhanging beam. 3. A cross beam between the overhanging beam and the side frame, which is located in front of the overhanging beam, is joined to a front end of the side frame, and extends in parallel with the overhanging beam. A substantially L-shaped cab support frame comprising a bottom plate and a vertical beam portion joined to the overhanging beam, the rear end side of which extends parallel to the bracket portion, and the reinforcing member is provided at the rear of the vertical beam portion. The revolving frame for a construction machine according to claim 1 or 2, wherein the revolving frame is configured to be joined to an end side and the bracket portion, respectively. 4. The reinforcing member is made of a plate material bent substantially in an L shape, the front end of the reinforcing member being the bottom plate, the rear end being the overhanging beam, the left end being the bracket part, and the right end being the right end. The revolving frame of a construction machine according to claim 3, wherein a closed space is defined inside by being joined to each of the vertical beam portions.