JP2001323496A - Plate joint structure of can assembly structure of construction machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need of using a patch to facilitate a welding operation when jointing horizontal plates forming a can assembly unit structure positioned at the front and rear sides to each other by a welding means. SOLUTION: The joined surface of a unit structure 30 to a horizontal plate 32 in a horizontal plate 36 on a unit structure 31 side of the unit structure 30 and the unit structure 31 is formed in a recessed cut-out part 40 at a portion between extended parts 36a on both sides thereof, and the joined surface of the horizontal plate 36 to the horizontal plate 36 of the unit structure 30 is formed in vertical planes 36V and 36V at the positions of both extended parts 36a and 36a and formed in a tapered surface 36T slanted diagonally forward from the upper end side to the lower end side at the positions between these two positions to form a groove 41 dividingly formed of a groove angle by the tapered surfaces 32T and 36T and a distance D. The groove 41 is formed in a bottomed groove closed at both ends thereof by both tapered surfaces 32T and 36T, a wall surface forming a transient part from the tapered surface 36T to the vertical surface 36V, and a rear plate 42.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a construction machine,
For example, the present invention relates to a plate joint structure for connecting and fixing a plurality of unit structures to each other by welding means in forming a can assembled structure such as a boom and an arm which constitute a front working machine of a hydraulic shovel. .

[0002]

2. Description of the Related Art An example of a construction machine is a hydraulic shovel. This hydraulic excavator has, for example, the configuration shown in FIG. In the drawing, reference numeral 1 denotes a lower traveling body, and 2 denotes an upper revolving superstructure. The upper swing body 2 is provided with a working machine 3 for performing work such as excavation of earth and sand. The work machine 3 includes a boom 4 connected to the upper swing body 2 so as to be capable of raising and lowering, an arm 5 connected to a tip of the boom 4 so as to be vertically rotatable, and a link mechanism 6 to a tip of the arm 5. And a bucket 7 as a front attachment connected to perform joint motion. And boom 4,
The arm 5 and the bucket 7 each have a hydraulic cylinder 4
a, 5a and 7a.

[0003] The boom 4 (and the arm 5) of the working machine 3 has a can-shaped structure having a rectangular cross section. Here, the base end side of the boom 4 is connected to the upper swing body 2 and the distal end side thereof is connected to the arm 5 via connecting pins, respectively. Are formed by sequentially connecting a plurality of unit structures assembled in a can by welding means. The boom 4 shown in FIG. 6 includes three can-assembled unit structures 10 to 12. The lower structure 10 is provided with a connection portion 13 to the upper revolving unit 2, and the intermediate structure 11 is provided with an arm 5.
A bracket 14 for fixing an end of a cylinder tube of a hydraulic cylinder 5a for driving the boom 4 and a cylinder connecting portion 15 to which a tip of a rod of the hydraulic cylinder 4a for driving the boom 4 are connected. Furthermore, upper structure 1
A connecting portion 16 for connecting to the arm 5 is provided at the tip of the second member 2.

For example, the lower structure 10 and the intermediate structure 1
FIGS. 7 to 9 show the configuration of the connecting portion between the first connecting member 1 and the second connecting member 1 (the same applies between the intermediate structure 11 and the upper structural grain 12). First, FIG. 8 shows a cross section of the lower structure 10. The lower structure 10 is composed of a pair of horizontal plates 20 and 21 arranged on the upper surface side and the lower surface side, respectively, and vertical plates 22 and 23 joined and fixed near the left and right sides. These horizontal plates 20,
21 and the vertical plates 22 and 23 are connected and fixed by welding means. Horizontal plate 20, vertical plates 22 and 23 of horizontal plate 21
The horizontal plate 20 and the horizontal plate 21 are slightly protruded outwardly from the left and right vertical plates 22 and 23 because the joints between the horizontal plates 20 and 21 are substantially right angles.
a and the outer surfaces at both ends of the left and right vertical plates 22 and 23 are welded along a corner portion formed by the welding.
It has high welding strength. The intermediate structure 11 to be welded to the lower structure 10 also has a back plate 2 to be described later.
Except for 5, the structure is substantially the same. Therefore,
In the following description, the lower structure 10 and the intermediate structure 11
In the case of distinguishing the respective components constituting the above, the former is given a subscript (L) and the latter is given a subscript (M).

The horizontal plates 20L, 21L of the lower structural part 10
Are welded to the horizontal plates 20M and 21M of the intermediate structure portion 11, and both the vertical plates 22L and 23L of the lower structure portion 10 are also welded to both the vertical plates 22M and 23M of the intermediate structure portion 11. The lower structure 10 and the intermediate structure 11 are connected so as to be substantially integrated. However, horizontal plate 2
When a load is applied to the boom 4 by dispersing the positions of the welded portions by displacing the welded portions of the welded portions 0 and 21 and the welded portions of the vertical plates 22 and 23 in the longitudinal direction of the boom 4 in different directions.
Extremely concentrated stress is prevented.

As shown in FIG. 7, in order to increase the welding strength in the above-mentioned welded portion, between the horizontal plates 20L and 20M (also between the horizontal plates 21L and 21M) on the lower structure portion 10 side and the intermediate structure portion 11 side. ) Are separated from each other by a distance d, and a groove angle is formed as tapered surfaces 20Lb, 20Mb in which the end faces of the horizontal plates 20L, 20M are directed in a direction to be separated from each other. Therefore, the distance V and the groove angle between the two tapered surfaces 20Lb and 20Mb are approximately V.
A groove 24 having a shape is formed, and welding is performed on the groove 24. By forming the groove 24 in such a shape, the amount of the deposited metal to be introduced can be increased, and the welding area between the horizontal plates 20L and 20M is increased.

Since a gap d is formed between the two horizontal plates 20L and 20M of the lower structure portion 10 and the intermediate structure portion 11, either one of the horizontal plates, for example, the horizontal plate 20L on the lower structure portion 10 side, is provided. The back plate 25 is fixed by a welding means or the like, and the groove 24 is formed as a groove with a bottom by protruding the back plate 25 toward the counterpart horizontal plate 20M by a predetermined length. The groove 24 extends over the entire length in the width direction, and both ends are open. The width of the back plate 25 is substantially the same as the interval between the inner surfaces of the vertical plates 22L and 23M. By arranging the back plate 25 along the groove 24 in this way, when welding is performed by introducing the weld metal into the groove 24, the weld metal is held so as not to leak.

However, the back plate 25 for covering the groove bottom of the groove 24 is provided for both the left and right vertical plates 22L,
This is the position between 23L. At the left and right sides of the back plate 25, the end faces of the vertical plates 22L and 23L also function as members that cover the inside of the groove 24. However,
As described above, the projecting portions 20La and 21Ma are provided on both left and right sides of the horizontal plates 20L and 21M, and there are no members in this portion that exert the same function as the back plate.
Therefore, as shown in FIG.
By contacting the backing plate 26 on the inside of the 21 Ma portion, a damming function for preventing leakage of the weld metal over the entire length of the groove 24 during welding is exerted.

[0009]

By the way, if the above-mentioned caul plate is left as it is after the front and rear can assembly unit structures are fixed by welding, the appearance deteriorates. After performing the welding, the backing plate must be removed. Therefore, it is necessary that the backing plate can be held in a stable state when welding is being performed, and that it can be easily removed after welding is completed. For this reason, the backing plate is known to be formed of, for example, a magnet, so that the backing plate can be fixed by a simple operation of merely contacting the overhang. However, by performing welding, this backing plate is fixed to the horizontal plate by the weld metal. For this reason, a large impact is applied to the caul plate with a hammer or the like to separate the caul plate from the horizontal plate, but since the caul plate is located at the corner portion, it is difficult to remove the caul plate, and Etc. may be shocked. Further, after the backing plate is peeled off, it may be necessary to perform processing such as adjusting the shape of the weld metal located therebetween.

The present invention has been made in view of the above points, and an object of the present invention is to joint a horizontal plate constituting a can-assembly unit structure located in front and rear by welding means. It is another object of the present invention to eliminate the necessity of using a backing plate and to facilitate the welding operation.

[0011]

In order to achieve the above-mentioned object, the present invention provides a horizontal plate comprising upper and lower surfaces,
A plurality of unit structures having left and right sides joined and fixed by welding means in the vicinity of both sides of the two horizontal plates and a plurality of unit structures having seams joined together by welding means. In addition, a back plate that projects by a predetermined length toward the other side at a position between the two vertical plates on one of the two horizontal plates joined by the welding means in the front and rear unit structures. A notch is formed at one end face of the two horizontal plates at a position between the joints of the two vertical plates, and both sides of the notch formation portion are on opposite sides of the horizontal plate. When the front and rear unit structures are joined, between the end faces of the opposing horizontal plates,
The notch forming portion and the back plate form a groove having a bottom and into which a weld metal whose both ends are closed is introduced.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the embodiment described below, a boom of a working machine in a hydraulic shovel as a construction machine will be described, but the present invention is not limited to this, and other can assembled structures, such as an arm, etc. Needless to say, it can also be applied to.

FIG. 1 shows the appearance of a joint portion between unit structures assembled in a can located at the front and rear. In the drawing, 30 is a unit structure on one side, and 31 is a unit structure on the other side. When these two unit structures 30 and 31 are applied to FIG.
If one is a lower structure, the other is an intermediate structure. In addition, the whole can-assembled structure is not limited to the one divided into three, but may be, for example, one divided into upper and lower parts. In short, the plate joint structure of the can-assembled structure of the present invention is applied to a structure in which the unit structures 30 and 31 located in front and rear are connected by welding means.

The unit structure 30 includes upper and lower horizontal plates 32, 33 and vertical plates 34, 35 forming left and right side plates.
It has a rectangular cross section,
The unit structure 31 also has a box-shaped can-assembled structure composed of horizontal plates 36 and 37 and left and right vertical plates 38 and 39, and at least their end faces have the same shape as the unit structure 30. It has dimensions. The two unit structures 30 and 31 have a connection structure by plate joining using welding means. The connection by the plate joining is provided between the horizontal plates 32 and 36, between the horizontal plates 33 and 37, and the vertical plate 3 respectively.
4 and 38 and between the vertical plates 35 and 39. Moreover,
The positions of the welds between the horizontal plates 32 and 36 and between the horizontal plates 33 and 37 and the positions between the vertical plates 34 and 38 and the vertical plates 35 and 39 are different in the longitudinal direction of the can assembled structure. To this end, the vertical plates 34 and 35 protrude from the ends of the horizontal plates 32 and 33 on the unit structure 30 side, and the vertical plates 38 and 39 are the horizontal plates 36 and 37 on the unit structure 31 side. Stopped at a position deeper than the end of

Thus, between the horizontal plates 32 and 36 on the upper surface side,
The welding structure between the horizontal plates 33 and 37 on the lower surface side is substantially the same. Therefore, in the following description, the horizontal plate 3
A description will be given of the plate joining structure by welding between the horizontal plates 2 and 36. However, the same configuration can be applied between the horizontal plates 33 and 37.

FIG. 2 shows a state in which the unit structures 30 and 31 are joined together, FIG. 3 shows a cross section taken along the line AA in FIG. 2, and FIG. 3 shows a cross section at a position B. As is clear from these figures and as described in the prior art, the horizontal plates 32 and 36 are respectively provided at predetermined positions outward from the joints / fixed portions to the vertical plates 34 and 35 and 38 and 39, respectively. Overhangs 32a, 36a of length only
Are formed to increase the welding strength at the joint / fixed portions of the vertical plates 34, 35 and 38, 39. In this respect, there is no particular difference from the configuration of the related art.

However, the connecting surface of the horizontal plate 36 on the unit structure 31 side to the horizontal plate 32 of the unit structure 30 is formed with a concave cutout portion 40 at a portion between the projecting portions 36a on both sides. I have. As shown in FIG. 3, the notch 40 is for forming a groove 41 when welding between the two horizontal plates 32 and 36. Here, the notch 40 is formed by the vertical plate 3 in the horizontal plate 36.
It is necessary that the width of the cutout portion 40 does not exceed this limit at the joint portion between the unit structures 8 and 39, so that the width of the cutout portion 40 does not exceed this limit.
From the viewpoint of the connection strength between 0 and 31, the notch 40 extends to the position of the outer surface of the joint with the vertical plates 38 and 39.

From the above, the shape of the end face of the joint of the horizontal plate 36 to the horizontal plate 32 on the unit structure 30 side is such that the vertical surfaces 36V, 36V at the positions of the overhang portions 36a, 36a shown in FIG. And these vertical surfaces 36V, 36
At the position between V, as shown in FIG. 3, there is a tapered surface 36T inclined obliquely forward from the upper end to the lower end. The angle of the tapered surface 36T forms a groove angle. In addition, since the end face of the horizontal plate 36 is cut out in a middle portion in a concave shape, the lower end of the tapered face 36T is located at a position deeper than the vertical plane 36V in the overhang 36a. That is, as is clear from FIG. 2, the leading edge of the tapered surface 36T is located inside the vertical surface 36V by the distance D. On the other hand, the unit structure 30
The shape of the joint surface of the horizontal plate 32 to the unit structure 31 side at the position of the overhang portion 32a is
2V and 32V.
Between V and 32V, there is a tapered surface 32T that expands in the opposite direction at the same angle as the tapered surface 36T of the horizontal plate 36. However, since the horizontal plate 32 does not have a notched shape, the position of the leading edge of the tapered surface 32T is
It is the same position as V.

Further, a back plate 42 is provided on the inner side of the horizontal plate 36.
Are fixed by welding means. The back plate 42 has a width dimension substantially matching the interval between the inner surfaces of the vertical plates 38, 39. The back plate 42 protrudes from the leading edge of the tapered surface 32T, and the protruding length is sufficiently longer than at least the interval D described above. The back plate 42 may be provided on the horizontal surface 32 side.

With the above configuration, the horizontal plates 3 in the unit structures 30 and 31 before and after are welded.
When connecting the sections between 2, 36, the unit structures 30,
31 are brought close to each other, and the horizontal plate 3 on the unit structure 31 side.
The tip of the back plate 42 protruding from 6 is pushed along the inner surface of the horizontal plate 32 of the unit structure 30 so that the vertical surfaces 32V, 36V of the horizontal plates 32, 36 abut against each other. As a result, the tapered surfaces 32T, 36 are provided between them.
A groove 41 defined by the groove angle formed by T and the interval D is formed.
Has a bottom with both tapered surfaces 32T and 36T, a wall surface forming a transition from the tapered surface 36T to the vertical surface 36V, and end surfaces of the back plate 42 and the vertical plates 38 and 39, and both ends are closed. Groove. And the bottom of the groove is the back plate 42
And the end faces of the vertical plates 38 and 39 located on both sides thereof. Therefore, there is no danger that the weld metal will flow out of the groove forming the groove 41 when welding in such a manner that the weld metal is melted into the groove forming the groove 41, as in the prior art. The welding can be performed without using the jig.

Here, the vertical surfaces 32 of the horizontal plates 32, 36
Since the joining portions of V and 36V are the overhanging portions 32a and 36a of the horizontal plates 32 and 36, it is not necessary to give any particular strength to these portions. However, if this joint is left in a free state, stress concentrates on the transition from the welded portion, causing cracks and the like. Therefore, as shown in FIG. 4, welding is performed along this joining line. However, welding of this portion does not require penetration of the deposited metal, but only simple welding is required.

As described above, since the both ends of the groove constituting the groove 41 are blocked, the deposited metal does not flow out at the time of welding. Since the operation of peeling off the backing plate after the welding is completed is not required, the welding operation can be easily performed.

[0023]

Since the present invention is constructed as described above, it is not necessary to use a backing plate in joining the horizontal plates constituting the front and rear can unit structure by welding means. This has the effect of facilitating welding work.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a joint portion of a unit structure showing one embodiment of the present invention.

FIG. 2 is a main part plan view showing a state before and after welding of the unit structures before and after being joined to each other.

FIG. 3 is a sectional view taken along line AA of FIG. 2 in a state after welding.

FIG. 4 is a sectional view taken along line BB of FIG. 2 in a state after welding.

FIG. 5 is an overall configuration diagram of a hydraulic excavator as an example of a machine including a can assembly structure.

FIG. 6 is a front view of a boom as a can assembled structure.

FIG. 7 is a plan view showing a conventional technique, in a state before welding, viewed from the direction of arrow X in FIG. 6;

8 is a sectional view taken along the line CC of FIG. 7;

FIG. 9 is a sectional view taken along line DD of FIG. 7 in a state after welding.

FIG. 10 is a sectional view taken along line EE of FIG. 7 in a state after welding.

[Explanation of symbols]

30, 31 unit structure 32, 33, 36,
37 horizontal plate 34,35,38,39 vertical plate 32a, 36a
Overhang 32T, 36T Tapered surface 32V, 36V Vertical surface 40 Notch 41 Groove 4
2 Back plate

Claims (2)

[Claims] 1. A plurality of unit structures each comprising a horizontal plate forming an upper surface and a lower surface, and vertical plates forming left and right both sides joined and fixed by welding means near both sides of these horizontal plates. In a can-assembled structure connected by welding means, the horizontal plate on one side of the two horizontal plates joined by the welding means in the front and rear unit structures is placed at a position between the two vertical plates. A back plate protruding by a predetermined length toward the opponent is fixedly provided, and a notch is formed at a position between the joints of the two vertical plates on one end surface of both the horizontal plates. On both sides of the notch forming portion, a joining surface to the mating horizontal plate is formed, and when the front and rear unit structures are joined, the notch forming portion and the back surface are provided between the end faces of the opposing horizontal plates. Welded metal with both ends closed by a plate A plate joining structure for a can assembled structure of a construction machine, characterized in that the groove is formed into the groove. 2. The plate joint of a can assembly structure of a construction machine according to claim 1, wherein the notch forming portion is formed at a position between outer surfaces of a joint portion of the two vertical plates. Construction.