JP2003129521A - Revolving frame of construction machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance workability in manufacture and assembly by simplifying welding work for a revolving frame, and enable a bracket part to secure adequate strength against an external force applied by a working device. SOLUTION: This revolving frame 11 of a hydraulic excavator is composed of: a base plate 12; right and left vertical plates 13 and 14 which are erected upward on the base plate 12 and extended in a lengthwise direction; and an upper plate 15 which is provided in front-side parts of the vertical plates 13 and 14 in such a manner as to face the base plate 12 in upper and lower positions, and has a supporting bracket 16 for the working device formed between the upper plate 15 and the base plate 12. Inserting joints 25 and 25, which are fitted into each other via a recess and a protrusion so as to increase strength of jointing between a rear-side part of the upper plate 15 and upper parts of the vertical plates 13 and 14, are provided between the rear-side part of the upper plate 15 and the upper parts of the vertical plates 13 and 14. Thus, the work for welding the upper plate 15 to the vertical plates 13 and 14 can be simplified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swing frame of a construction machine, which is preferably used for an upper swing body such as a hydraulic excavator.

[0002]

2. Description of the Related Art Generally, construction machines such as hydraulic excavators are
It is composed of a lower traveling body, an upper revolving body rotatably mounted on the lower traveling body, and a working device provided on the front side of the upper revolving body for excavating earth and sand.

Further, in a small hydraulic excavator or the like called a so-called mini excavator, a boom of a working device is connected to a revolving frame of an upper revolving structure so as to be swingable in left and right directions by using a swing post or the like. It is known that the swing post type working device is adopted (for example, Japanese Patent Laid-Open No. 2000-27235).

A pivoting frame according to the prior art of this kind is
A bottom plate rotatably mounted on the undercarriage, left and right vertical plates standing upright from the bottom plate and extending in the front and rear directions of the bottom plate, and the bottom plate and the upper plate provided on the front side of each vertical plate. , And an upper plate and the like which are arranged to face each other below.

The upper plate is formed of, for example, a substantially triangular flat plate member, and a bracket portion for swingably supporting the swing post type working device is located at the front end side of each vertical plate. And is formed between the base plate and the bottom plate.

[0006]

In the swivel frame according to the prior art described above, the left and right vertical plates are joined by welding to the bottom plate, and the bottom plate and the upper plate are connected to the front side of these vertical plates.
While joining the upper plate by welding so that it faces below,
A bracket portion for swingably supporting the swing-post type working device is constituted by the upper plate and the bottom plate which face each other so as to sandwich the front end sides of the left and right vertical plates between the upper and lower sides.

Since such a bracket portion is frequently subjected to a large load applied from the outside, such as an excavation reaction force from a working device, stress concentration is likely to occur and, for example, left, Between the right vertical plate and the upper plate, etc., it is required to increase the number of weld beads and firmly bond them together.

Therefore, in the prior art, when manufacturing and assembling the revolving frame, a great amount of labor and time are spent on the welding work in the vicinity of the bracket portion, it is difficult to improve workability, and a large amount of welding beads are generated. Therefore, there is a problem that the finishing work using a grinder or the like thereafter takes time and the burden on the worker increases.

The present invention has been made in view of the above-mentioned problems of the prior art. An object of the present invention is to simplify welding work and improve workability at the time of manufacturing and assembling, and to receive a bracket portion from a work device. It is intended to provide a swing frame of a construction machine capable of ensuring sufficient strength against external force.

[0010]

In order to solve the above-mentioned problems, the present invention provides a bottom plate provided on a lower traveling body via a slewing wheel, and a front plate standing upright from the bottom plate. , Equipped with left and right vertical plates extending in the rearward direction and upper plates provided on the front side of the vertical plates and facing the bottom plate above and below, and swinging the working device by the bottom plate, each vertical plate and the upper plate. It is applied to a swing frame of a construction machine, which is formed with a bracket portion for movably supporting it.

A feature of the structure adopted by the invention of claim 1 is that a plug-in joint portion is provided between the upper plate and the vertical plate for increasing the joint strength between them.

With this structure, the joint strength between the upper plate and the vertical plate can be increased by using the insertion joint portion, and the work of welding the upper plate to the vertical plate can be simplified. be able to.

According to the second aspect of the present invention, the insertion joint portion is configured such that the rear side portion of the upper plate is fitted into the upper side portion of the vertical plate in a concavo-convex manner. In this case, by inserting the rear side portion of the upper plate into the upper side portion of the vertical plate by concavo-convex fitting, it is possible to form a plug-in joint between the upper plate and the vertical plate.

According to the third aspect of the present invention, the insertion joint portion is formed by a notch recess formed in the upper side portion of the vertical plate and fitted with the rear side portion of the upper plate. In this case, by inserting a part of the upper plate into the cutout recess formed in the upper portion of the vertical plate, the insertion joint can be formed between the upper plate and the vertical plate.

Further, according to the invention of claim 4, the insertion joint portion is a cutout recess formed in the upper plate, and a fitting projection formed in an upper portion of the vertical plate so as to be fitted into the cutout recess. It consists of and. In this case, the insertion joint can be formed by fitting the fitting protrusion formed on the upper side portion of the vertical plate into the notch recess formed on the upper plate.

Further, according to the invention of claim 5, the insertion joint portion is formed in the notch concave portion formed in the upper plate and in the upper portion of the vertical plate corresponding to the notch concave portion, and is inserted into the notch concave portion. It is composed of another notch recess which is fitted in such a manner as to be fitted.

Thus, the notched concave portion on the upper plate side and the notched concave portion on the vertical plate side can be fitted so as to be inserted into each other to form the insertion joint portion.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the swing frame of a construction machine according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings, taking a case where it is applied to a small hydraulic excavator as an example.

Here, FIGS. 1 to 10 show the first embodiment of the present invention.
The embodiment of is shown. In the figure, 1 is a lower traveling body, 2
Is an upper revolving structure mounted on the lower traveling structure 1 so as to be revolvable by using revolving wheels 3, and the upper revolving structure 2 has a revolving frame 11 described later.

The upper swing body 2 is provided with an outer cover 4, a driver's seat 5, a canopy 6, a counterweight 7 and the like which are located on the revolving frame 11, and the outer cover 4 together with the counterweight 7 serve as an engine. , A machine room for accommodating hydraulic pumps (neither shown) and the like is defined.

Reference numeral 11 denotes a revolving frame which constitutes a main frame of the upper revolving structure 2, and the revolving frame 11 is formed of a flat plate material as shown in FIGS.
A bottom plate 12 extending in the front and rear directions, and vertical plates 13 and 1 described later.
4, upper plate 15, reinforcing plate 18, lateral plate 19, weight mounting plate 20, and the like.

The bottom plate 12 of the swivel frame 11 has a large number of bolt holes 12A, 12A, ... At intervals of, for example, about 10 to 20 so as to form a concentric circle with respect to the swivel center O as shown in FIG. Are formed and these bolt holes 1
Bolts (not shown) for attaching the swivel wheel 3 to the lower traveling body 1 shown in FIG.

As a result, the bottom plate 12 of the revolving frame 11 is
Has a central portion in the longitudinal direction (front and rear directions) mounted rotatably on the lower traveling body 1 via the slewing wheel 3, and has a slewing center O
It is driven to turn left and right around the center.

Reference numerals 13 and 14 are left and right vertical plates extending in the front and rear directions, which are provided upright on the upper surface side of the bottom plate 12.
As shown in FIG. 5, 14 is arranged so as to be spaced apart from both sides of the turning center O on the left and right sides and to extend in a substantially "C" shape, and its front end side will be described later as shown in FIGS. Left on the boss cylinder 17,
It is joined from both sides on the right.

The left vertical plate 13 is the upper plate 1 described later.
5 and the horizontal plate 19 extend linearly and obliquely, and the front upper end side thereof has a flat joint surface portion 13A to which the left lower surface of the upper plate 15 is joined as shown in FIGS. 6 and 9. And a stepped projection 13B which is located on the rear end side of the joining surface portion 13A and which projects upward and has a cutout recess 25A described later.

The right vertical plate 14 extends forwardly and backwardly on the bottom plate 12 as shown in FIG. 5, but the front side of the right vertical plate 14 is inclined substantially toward the upper plate 15 described later. It bends and extends like a letter. Also, as shown in FIGS. 4 and 9, a flat joint surface portion 14A to which the right lower surface of the upper plate 15 is joined and a rear end portion of the joint surface portion 14A are also located on the upper end side of the vertical plate 14. And a stepped protrusion 14B which is protruded upward and in which a notch recess 25A described later is formed.

Further, the vertical plates 13 and 14 are the revolving frame 1
In order to increase the bending rigidity of the vertical plate 1, the vertical plate 13 is erected upward from the upper surface of the bottom plate 12 as shown in FIGS. 2 to 4, and the height dimension of the vertical plate 13 is slightly higher than that of the vertical plate 14. .

Reference numeral 15 denotes an upper plate which covers the front sides of the vertical plates 13 and 14 from the upper side. The upper plate 15 is formed of a substantially triangular flat plate member as shown in FIGS. , 14 are joined to the joining surface portions 13A and 14A, a notch recess 25A described later, and the like by using welding means. And the upper plate 15 is
By supporting the front side of the bottom plate 12 at the upper side and the lower side, a support bracket 16 described later is configured with the bottom plate 12.

Reference numeral 16 is a support bracket as a bracket portion provided on the front side of the vertical plates 13 and 14, and the support bracket 16 has a bottom plate 12 as shown in FIGS.
Front part, front parts of vertical plates 13 and 14 and upper plate 15
And has a pin hole 16A and the like extending vertically through the bottom plate 12 and the upper plate 15.

The bottom plate 12 is attached to the support bracket 16.
A boss cylinder 17 is provided between the upper plate 15 and the upper plate 15 by welding, and the boss cylinder 17 is positioned coaxially with the pin hole 16A and extends upward and downward. And the support bracket 1
6 has a configuration in which the front ends of the left and right vertical plates 13 and 14 are joined to the outer peripheral surface of the boss cylinder 17 by welding.

The support bracket 16 has a pin hole 1
6A and a vertical connecting pin (not shown) inserted into the boss cylinder 17 constitute a bracket portion that rotatably supports a swing post 27 of a working device 26 described later.

Reference numeral 18 is a reinforcing plate for increasing the bending strength of the support bracket 16. The reinforcing plate 18 is located between the left and right vertical plates 13 and 14 as shown in FIGS. Board 1
5 and the bottom plate 12, and the left and right ends thereof are joined to the vertical plates 13 and 14 by welding.

The reinforcing plate 18 extends obliquely between the upper plate 15 and the bottom plate 12 as shown by the dotted lines in FIGS. 4 and 6, and the upper end thereof is on the rear end side of the upper plate 15. The lower end side is joined to the upper surface of the bottom plate 12. The reinforcing plate 18 is provided between the left and right vertical plates 13 and 14 and the bottom plate 12 and the upper plate 1.
5 is closed so as to form a hollow box structure between the rear end side and the rear end side, and the entire support bracket 16 is thereby reinforced as a box structure.

Reference numeral 19 denotes a horizontal plate which is located on the rear end side of the vertical plates 13 and 14 and stands upright on the bottom plate 12. The horizontal plate 19 is the bottom plate 1.
2 and the vertical plates 13 and 14 are formed by using a steel plate that is thinner than the vertical plates 13 and 14, and are joined to the upper surface of the bottom plate 12 and the vertical plates 13 and 14 using welding means. And the horizontal plate 19
Connects the left and right vertical plates 13 and 14 to each other on the bottom plate 12.

Reference numeral 20 denotes a weight mounting plate fixed to the rear end side of the bottom plate 12 by means such as welding. The weight mounting plate 20 is composed of a plate member extending in the left-right direction, and the upper surface of the bottom plate 12 and a rear surface which will be described later. It is provided so as to be joined to the rear ends of the vertical plates 21 and 22. And the weight mounting plate 20
1, the counterweight 7 shown in FIG. 1 is detachably attached using a bolt or the like.

Reference numerals 21 and 22 denote a horizontal plate 19 and a weight mounting plate 2.
0, which are left and right rear vertical plates spaced apart left and right from each other, the lower vertical sides of the rear vertical plates 21 and 22 are joined to the rear side of the bottom plate 12, and the rear end sides thereof are weighted. Each is joined to the mounting plate 20. Further, the rear vertical plates 21, 22 are joined at their front end sides to the left and right end sides of the horizontal plate 19, and are arranged so as to sandwich the horizontal plate 19 from the front and rear directions with the rear ends of the vertical plates 13, 14. It is set up.

23A, 23B, 23C and 23D are bottom plates 1
2 is an engine mount provided on the rear side, and the engine mounts 23A to 23D are the exterior covers 4 shown in FIG.
The engine and the like housed therein are supported from below.

A mounting bracket 24 is provided between the left vertical plate 13 and the bottom plate 12, and the mounting bracket 24
3 protrudes outward (to the left in FIG. 5) from the vertical plate 13 as shown in FIGS.
A hydraulic cylinder (not shown), which serves as a swing actuator, is attached between and. This hydraulic cylinder swings (swings) the entire working device 26 described later together with the swing post 27 to the left and right.

Reference numerals 25 and 25 denote two insertion joint portions adopted in the present embodiment. Each of the insertion joint portions 25 is formed on the stepped projection 14B of the vertical plate 14 as shown in FIG. 9, for example. It is composed of an elongated U-shaped cutout recess 25A and a right rear end portion 25B of the upper plate 15 (a portion indicated by a chain double-dashed line in FIG. 9), and the lower surface of the cutout recess 25A is flatly joined to the vertical plate 14. It is arranged on the same plane as the surface portion 14A.

Then, the insertion joining portion 25 is such that the upper plate 1 is placed on the joining surface portion 14A of the vertical plate 14 in the state where the upper plate 15 is placed.
9 with the right rear end portion 25B of FIG.
It is configured by pushing it in the direction of the arrow A in the middle and fitting both of them together as shown in FIG.

Also, between the left side vertical plate 13 and the left side rear end portion of the upper plate 15, there is formed a similar spliced joint 25 as shown in FIGS. Further, this insertion joining portion 25 is also constituted by a notch recess 25A or the like formed in the stepped protrusion 13B of the vertical plate 13, and the notch recess 25
A rear end portion of the left side of the upper plate 15 is recessed and fitted into A.

These plug-in joints 25 are formed by fitting the rear end side of the upper plate 15 into the recessed recesses 25A of the vertical plates 13 and 14 by concavo-convex fitting, and then the vertical plates 13, 1
The welding work is carried out in the same manner as the joining surface portions 13A and 14A side of No. 4.

As shown in FIG. 1, reference numeral 26 is a swing-post type working device provided on the front side of the upper swing body 2. The working device 26 is rotated by using a connecting pin or the like on the support bracket 16 of the swing frame 11. A swing post 27 that is movably connected, a boom 28 that is movably connected to the upper end of the swing post 27, an arm 29 that is movably connected to the tip end side of the boom 28, and the arm. It is generally constituted by a bucket 30 rotatably connected to the tip end side of 29.

Here, the swing post 27 and the boom 28
A boom cylinder 28A is provided between and, and the boom 28 is lifted up and down by the boom cylinder 28A. The arm 29 is operated by the arm cylinder 29A, and the bucket 30 is operated by the bucket cylinder 30A.

In the working device 26, the swing post 27 is swung horizontally (left and right) with respect to the support bracket 16 of the revolving frame 11 when, for example, diving work is performed. The entire device 26 is swung to the left and right with respect to the turning frame 11.

Further, 31 is an earth discharging plate provided on one side in the front and rear directions of the lower traveling body 1, and the earth discharging plate 31 is used when, for example, leveling work or earth discharging work is performed. It is a thing. The earth discharging plate 31 also has substantially the same function as an outrigger for stabilizing the vehicle posture.

The small hydraulic excavator according to the present embodiment has the above-mentioned structure, and its operation will be described below.

First, when the hydraulic pump is driven by the engine housed in the exterior cover 4, the pressure oil from the hydraulic pump is supplied to and discharged from the traveling motor of the lower traveling body.
The excavator (vehicle) can be driven to move forward or backward.

When excavating earth and sand or the like, the boom 28 can be raised and lowered by supplying and discharging the pressure oil from the hydraulic pump to the boom cylinder 28A, and the arm 29 presses the arm cylinder 29A. It is operated by supplying and discharging.

Further, the bucket 30 can be driven by supplying / discharging the pressure oil to / from the bucket cylinder 30A. In this way, while the boom 28 and the arm 29 are raised and lowered, the bucket 3 is driven.
By rotating 0, the working device 26 moves the bucket 3
0 is used to excavate earth and sand.

By the way, during excavation work such as earth and sand, the bucket 30 receives an excavation reaction force, and the excavation reaction force is applied to the arm 29,
It is transmitted to the swing frame 11 side of the upper swing body 2 through the boom 28, the swing post 27, and the like. Then, on the turning frame 11 side, an external force such as an excavation reaction force is applied to the left and right vertical plates 13 and 14 and the upper plate 1 from the support bracket 16 shown in FIG.
It is transmitted as a bending load to and from 5, etc.

Therefore, in the present embodiment, the left and right vertical plates 13, which are erected on the bottom plate 12 of the revolving frame 11,
Left and right plug-in joints 25, 25 are provided between the upper end plate 15 and the rear end of the upper plate 15 to increase the joint strength between the vertical plates 13, 14 and the upper plate 15.

In this case, the insertion joining portion 25 between the right vertical plate 14 and the upper plate 15 is in a state where the upper plate 15 is placed on the joining surface portion 14A of the vertical plate 14 as shown in FIGS. so,
The right rear end portion 25B of the upper plate 15 is pushed toward the inside of the cutout recessed portion 25A, so that the two are fitted in a concavo-convex shape.

Further, as for the insertion joint portion 25 between the left vertical plate 13 and the upper plate 15, as shown in FIG. 6, with respect to the cutout recess 25A formed in the stepped projection 13B of the vertical plate 13. By pushing the left rear end of the upper plate 15, the upper plate 1
The left rear end portion of No. 5 is fitted into the notch recess 25A by projections and depressions.

As a result, the left and right vertical plates 13 and 14 and the rear end of the upper plate 15 are connected to each other by the plug-in joints 25 and 25. 15
Can be firmly joined by welding means, and the joining strength between the two can be reliably increased.

Therefore, unlike the prior art, it is not necessary to spend a great deal of labor and time on the welding work in the vicinity of the bracket portion (support bracket 16), and the welding work can be simplified and the workability at the time of manufacturing and assembling can be improved. At the same time, the welding work can be automated and the cost can be reduced.

Further, since the external load or the like acting on the support bracket 16 can be received by the plug-in joint portion 25, the load load at the welded portion can be reliably reduced, and it is carried out after the welding bead is formed, for example, by using a grinder or the like. The finishing work that was previously performed can also be simplified, and the burden on the operator can be reduced.

Further, in this embodiment, the vertical plate 1
Even when a twisting force or the like acts as an external force on a welded portion between the upper plate 15 and the upper plate 15, the rigidity against the twisting force can be added between the vertical plates 13 and 14 and the upper plate 15 by the insertion joint 25. The torsional rigidity can be reliably improved.

The support bracket 16 of the swivel frame 11 can secure sufficient strength against an external force received from the working device 26, and the bottom plate 12 and the vertical plate 1 of the swivel frame 11 can be secured.
It is possible to reduce the thickness of the plates 3, 14 and the upper plate 15 and to reduce the weight of the revolving frame 11 as a whole and reduce the cost.

Next, FIGS. 11 and 12 show the second embodiment of the present invention.
In the present embodiment, the same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

However, the feature of this embodiment is that the vertical plate 41 is
And the upper plate 42, the insertion joint portion 43 is provided between the upper plate 4 and
2A and 2B, and a fitting protrusion 43B formed on the upper end side of the vertical plate 41 so as to fit with the notch recess 43A.

Here, the vertical plate 41 is formed in substantially the same manner as the right vertical plate 14 described in the first embodiment, and has a flat joint surface portion 41A and a stepped protrusion 41B. However, the stepped protrusion 41B of the vertical plate 41 rises from the rear end side of the joint surface portion 41A so as to form an L shape, and the lower end side thereof constitutes the fitting protrusion 43B of the insertion joint portion 43.

The upper plate 42 is formed in the same manner as the upper plate 15 described in the first embodiment except for the cutout recess 43A. Then, in the insertion joint portion 43, the fitting protrusion 43B on the vertical plate 41 side is inserted into the cutout recess 43A on the upper plate 42 side as shown in FIG.
It is configured by fitting concave and convex in the direction of arrow A in 1.

Thus, the present embodiment having such a configuration can obtain substantially the same operational effects as those of the first embodiment, but particularly in the present embodiment,
Since the notch recess 43A is formed in the upper plate 42 and the fitting protrusion 43B is left in the vertical plate 41, the strength of the vertical plate 41 can be increased.

Next, FIGS. 13 and 14 show the third embodiment of the present invention.
In the present embodiment, the same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

However, the feature of this embodiment is that the vertical plate 51 is
And the upper plate 52, the insertion joint portion 53 provided between the upper plate 5
2 and the other notch recess 5 formed on the upper end side of the vertical plate 51 corresponding to the notch recess 53A.
It is composed of 3B and 3B.

Here, the vertical plate 51 is formed in substantially the same manner as the right vertical plate 14 described in the first embodiment, and has a flat joint surface portion 51A and a stepped protrusion 51B. However, the stepped projection 51B of the vertical plate 51 is located on the same plane as the joint surface portion 51A, and the notch recess 53B of the insertion joint portion 53 is formed.
Are formed.

The upper plate 52 is formed in the same manner as the upper plate 15 described in the first embodiment except for the cutout recess 53A. Then, the insertion joint portion 53 has a cutout recess 53B on the vertical plate 51 side and a cutout recess 53A on the upper plate 52 side in FIG.
It is configured by fitting concave and convex in the direction of arrow A inside.

Thus, the present embodiment having such a configuration can also obtain substantially the same operational effects as those of the first embodiment, but particularly in the present embodiment,
Notch recess 53B on the vertical plate 51 side and notch recess 5 on the upper plate 52 side
Since 3A and 3A are fitted into each other by projections and depressions, the strength around the insertion joint portion 53 can be more reliably improved.

In the second embodiment, the case where the insertion joint portion 43 is provided between the right vertical plate 41 and the upper plate 42 has been described as an example, but the present invention is not limited to this. ,
For example, the same insertion joint 43 may be provided between the left vertical plate and the upper plate 42. This point is the same as in the third embodiment.

In each of the above embodiments, the case where the support bracket 16 is provided with the boss cylinder 17 positioned between the bottom plate 12 and the upper plate 15 has been described as an example, but the present invention is not limited to this. However, the bracket portion (support bracket) may be configured by omitting the boss cylinder, as in the turning frame described in JP 2000-120107 A, for example.

Further, in each of the above-mentioned embodiments, the hydraulic excavator in which the driver's seat 5 is covered from above by using the canopy 6 has been described as an example, but the present invention is not limited to this, and for example, an open / close type. It may be applied to a hydraulic excavator or the like having a box-shaped cab that defines a driver's cab inside with a door of, and may be applied to a swing frame of various construction machines such as hydraulic excavators other than this. It's good.

[0073]

As described above in detail, according to the invention described in claim 1, between the upper plate and the vertical plate forming the bracket portion for the working device with the bottom plate, the joint strength between the two members is provided. Since it is configured to provide a plug-in joint for increasing the joint strength, the joint strength between the upper plate and the vertical plate can be increased by the plug-in joint, which is great for welding work in the vicinity of the bracket as in the prior art. Eliminates the need for labor and time. Also, since the load such as the external force acting on the bracket can be received at the joint, the load on the welded part can be reliably reduced, and for example, the finishing work using a grinder etc. after forming the weld bead can be simplified. It can be carried out.

Therefore, the welding work of the revolving frame can be simplified, the workability at the time of manufacturing and assembling can be improved, and the welding work can be automated. Then, the bracket portion of the swivel frame can secure sufficient strength against an external force received from the working device, the thickness of the bottom plate, the vertical plate, the upper plate, etc. of the swivel frame can be reduced, and the weight of the swivel frame as a whole can be reduced. It is possible to reduce the cost.
Further, even when a twisting force or the like acts as an external force on the welded portion between the vertical plate and the upper plate, the rigidity with respect to this twisting force can be reliably improved by the insertion joint.

Further, according to the invention of claim 2, the rear side portion of the upper plate is fitted into the upper side portion of the vertical plate in a concavo-convex manner,
An insertion joint can be formed between the upper plate and the vertical plate, the joint strength between the upper plate and the vertical plate can be increased, and the load burden on the welding location can be reduced, making it possible to perform welding work near the bracket part. It can be simplified.

Further, according to the third aspect of the present invention, by inserting the rear side portion of the upper plate into the notched concave portion formed in the upper side portion of the vertical plate, the insertion joint portion between the upper plate and the vertical plate is formed. Can be formed, and even in this case, the bonding strength between the upper plate and the vertical plate is increased,
The welding work in the vicinity of the bracket portion can be simplified.

Further, according to the invention described in claim 4, by inserting the fitting protrusion formed on the upper side portion of the vertical plate into the notch recess formed on the upper plate, the insertion joint can be formed. The joint strength between the upper plate and the vertical plate can be increased, and the welding work in the vicinity of the bracket portion can be simplified.

Further, in the invention as set forth in claim 5, a notch recess is formed in the upper plate, and the upper plate of the vertical plate is fitted into the notch recess so as to be inserted into the notch recess corresponding to the notch recess. Since the notch concave portion is formed, the notch concave portion on the upper plate side and the notch concave portion on the vertical plate side can be fitted so as to be inserted into each other to form the insertion joint portion, and the notch concave portion can be formed between the upper plate and the vertical plate. The joint strength of can be increased more reliably.

[Brief description of drawings]

FIG. 1 is a front view showing a hydraulic excavator according to a first embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing only a turning frame in FIG.

FIG. 3 is a perspective view of the swivel frame of FIG. 2 as viewed from the opposite side.

4 is a front view of the swivel frame shown in FIG. 2. FIG.

5 is a plan view of the swivel frame shown in FIG. 4. FIG.

6 is a rear view of the swivel frame shown in FIG. 4. FIG.

7 is a right side view of the swivel frame shown in FIG. 4. FIG.

8 is a left side view of the swivel frame shown in FIG. 4. FIG.

FIG. 9 is an exploded perspective view showing an enlarged insertion joint between the vertical plate and the upper plate shown in FIG.

FIG. 10 is a perspective view showing a state in which the plug-in joint portion of FIG. 9 is assembled.

FIG. 11 is an exploded perspective view of an insertion joint portion according to the second embodiment.

12 is a perspective view showing a state in which the plug-in joint portion of FIG. 11 is assembled.

FIG. 13 is an exploded perspective view of an insertion joint portion according to the third embodiment.

14 is a perspective view showing a state in which the plug-in joint portion of FIG. 13 is assembled.

[Explanation of symbols]

1 Undercarriage 2 Upper revolving structure 3 slewing wheels 4 Exterior cover 5 driver's seat 7 counterweight 11 swivel frame 12 Bottom plate 13,14,41,51 Vertical plate 13A, 14A, 41A, 51A Bonding surface part 13B, 14B, 41B, 51B Stepped protrusion 15, 42, 52 Upper plate 16 Support bracket (bracket part) 20 weight mounting plate 25,43,53 plug joint 25A, 43A, 53A Notched recess 26 Working device 27 swing post 43B Mating protrusion 53B Notch recess

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazunori Yamada             1-2, Sasagaoka, Mizuguchi Town, Koga District, Shiga Prefecture             Hitachi Construction Machinery Tierra Shiga Factory (72) Inventor Makoto Sugaya             Hitachi Construction Machinery Co., Ltd.             Ceremony Company Tsuchiura Factory (72) Inventor Makoto Makoto             1-2, Sasagaoka, Mizuguchi Town, Koga District, Shiga Prefecture             Hitachi Construction Machinery Tierra Shiga Factory

Claims (5)

[Claims] 1. A bottom plate provided on a lower traveling body via a slewing wheel, and a front plate standing upright from the bottom plate,
The left and right vertical plates extending in the rearward direction and the upper plate provided on the front side of each vertical plate and facing the bottom plate above and below are provided, and the working device is rocked by the bottom plate, each vertical plate and the upper plate. In a swing frame of a construction machine, in which a bracket portion for supporting in a possible manner is formed, an insertion joint portion for increasing the joint strength between the upper plate and the vertical plate is provided. Swivel frame of the construction machine that features. 2. The swivel frame for a construction machine according to claim 1, wherein the plug-in joint portion is configured such that a rear side portion of the upper plate is recessed and engaged with an upper side portion of the vertical plate. 3. The construction machine according to claim 1, wherein the plug-in joint portion is formed by a notch recess formed in an upper portion of the vertical plate and fitted with a rear portion of the upper plate. Swirl frame. 4. The insertion joint portion comprises a notch recess formed in the upper plate, and a fitting protrusion formed in an upper portion of the vertical plate so as to fit with the notch recess. A swivel frame for a construction machine according to claim 1 or 2. 5. The insert joint is formed in a notch recess formed in the upper plate, and is formed in an upper portion of the vertical plate corresponding to the notch recess so as to be inserted into the notch recess. 3. The structure according to claim 1 or 2, which is composed of another notch recess.
Slewing frame of construction machine described in.