JPH04120321A - Counterweight - Google Patents

Abstract

PURPOSE:To increase the rigidity of a rear plate for the elimination of a reinforcement plate, and prevent the occurrence of weld strain or the like on the rear plate by press-molding the rear plate into a circular arc shape having upper and lower end sections and right and left side end sections. CONSTITUTION:A rear plate 23 is press molded into a circular arc shape forming an upper end section 23A, a lower end section 23B and right and left side end sections 32C. Thereafter, a side plate is formed with each end section 32C of the rear plate 23. Furthermore, a portion of a top plate 24 and a bottom plate 25 is formed with the upper and lower end sections 23A and 23B of the rear plate 23. Thereafter, a hollow section formed with front and rear plates 22 and 23, top and bottom plates 24 and 25, and right and left side plates is filled with a weight adjustment material. According to the aforesaid construction, the rigidity of the rear plate 23 can be increased to eliminate a reinforcement plate, and the occurrence of weld strain or the like on the surface of the rear plate 23 can be prevented. In addition, a counterweight can be manufactured with press working at lower cost.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a counterweight suitably used in construction machinery such as a hydraulic excavator, and particularly relates to a counterweight that is filled with a weight adjusting material inside. .

[Prior Art] FIGS. 6 to 10 show an example of a hydraulic excavator equipped with a conventional counterweight.

In the figure, reference numeral 1 denotes an undercarriage body, and 2 denotes an upper revolving body rotatably mounted on the undercarriage 1. The upper revolving body 2 includes a driver's cab 42 and a machine room 5 provided on a revolving frame 3.
and a counterweight 7, which will be described later, and a working device 6 is provided at the front of the revolving frame 3 so as to be movable up and down. The working device 6 includes a boom 6A and an arm 6.
B, a packet 60, etc., and is designed to perform excavation work such as earth and sand.

Reference numeral 7 indicates a counterweight provided at the rear of the revolving upper structure 2 to balance the working device 6, and the counterweight 7 is formed into a substantially rectangular flat plate shape as shown in FIGS. 7 to 10. a front plate 8; a rear plate 10 disposed in an arc shape behind the front plate 8 and welded to the front plate 8 via left and right side plates 9;゜Welded to the upper end side of each side plate 9 and front plate 8,
Top plates 11A, IIB, IIC (referred to as the top plate 11 as a whole) are made up of a plurality of flat plates whose upper ends are closed, and a front plate 8. It is formed into a hollow structure by a lower surface plate 12 made of a plurality of flat plates that is welded to the lower end side of each side plate 9 and the rear plate 10 and closes the lower end side of these. Upper and lower side plates 13 forming part of
．． 14 are integrated by welding.

Here, each of the side plates 13 and 14 is curved corresponding to the four corners of the rear plate 10, and its front and rear ends are welded to the front plate 8 and the rear plate 9, and its upper end is the upper plate 11A.

It is welded to the left and right end faces of 11B. And the front plate 8. Each side plate9. Rear plate 10. Top plate 11, bottom plate 12
The counterweight 7 formed into a hollow structure by the side plates 13 and 14 is filled with a weight adjustment material (not shown) made of concrete, iron pieces, etc., and the weight balance of the upper revolving body 2 with respect to the working device 6 is adjusted. 15.15. . . . indicates reinforcing plates spaced apart in the left-right direction of the counterweight 7 and fixed between the front plate 8 and the rear plate 10, each reinforcing plate 15 extending in the front-rear direction inside the counterweight 7, and The front end is welded to the front plate 8, and the rear end is welded to the rear plate 10. Each of the reinforcing plates 15 is inserted into the rear plate 10, for example, when filling the weight adjusting material.
This is to prevent deformation due to the load in the direction of arrow A shown in FIG. Further, reference numeral 16.16 indicates a screw member as a bracket fixed to the top plate 11, and each screw member 16 is connected to the top plate 11A, 11B, II.
It is located between C and welded to the top plate 11A, 11B 11C, etc., and an eye bolt (not shown) or the like is screwed into it when the counterweight 7 is lifted or suspended.

The conventional counterweight 7 for a hydraulic excavator has the above-mentioned mechanism.Next, the manufacturing process thereof will be described.

First, the rear plate 10 is formed by rolling a plate material thicker than the front plate 8 together with each side plate 9 to have a predetermined curvature, and by bending both left and right ends, each side plate It is formed integrally with 9. Then, the front plate 8 is welded to the front end of each side plate 9, and the front plate 8.
Each reinforcing plate 15 is welded between the rear plates 10, and the upper plate 11A, JIB, and lower plate 12 are welded to the upper and lower end sides of both. Further, on the upper and lower ends of each side plate 9, a top plate 11A,
Upper and lower side plates 13 and 14 are welded between IIB and the lower plate 12, and the front and rear ends of each side plate 13 and 14 are connected to the front plate 8. It is welded to each corner of the rear plate 10.

Then, each screw member 16 is attached to the end surface of the top plate 11A, IIB.
are welded to form a counterweight 7 having a hollow structure, leaving the central top plate 11C, and filling the counterweight 7 with a weight adjustment material, and then welding the top plate 11A.
, 118, and the top plate 11C is welded to each screw member 16, and the counterweight 7
It is sealed to prevent rainwater from entering inside.

Next, the counterweight 7 manufactured in this way is attached to the rear surface of the upper revolving structure 2 by screwing an eye bolt or the like to each screw member 16, passing a wire through each eye bolt, and lifting the counterweight 7 with a crane or the like. It is attached removably and is designed to balance the weight with respect to the working device 6.

[Problem to be solved by the invention 1 By the way, in the above-mentioned conventional technology, the counterweight 7
In order to prevent the rear plate 10 from being deformed by the load in the direction of arrow A shown in FIG. 15, welding distortion may occur on the surface of the rear plate 10, causing unevenness on the surface of the rear plate 10, which forms part of the external appearance of the hydraulic excavator, and reducing the product value. There's a problem.

Also, each side plate 13.14 forming a part of each side plate 9 is welded to each corner of the rear plate 10.
The welded parts 13A and 14A are important parts for the appearance of the counterweight 7, and if they come into contact with the worker when the hydraulic excavator turns, the worker may be injured, so these welded parts 13A and 14A are There is a problem in that it is necessary to perform finishing with a grinder, etc., and this finishing process is time-consuming.

Furthermore, the dimension B (see FIG. 7) between each side plate 9 is the same as that between the rear plate 10 and the top plate 11. The bottom plate 12 is welded, and each side plate 13,
When welding 14, etc., variations are likely to occur due to welding distortion, etc., and it is difficult to keep the dimension B within a predetermined tolerance, and the number of parts increases due to each side plate 13° 14 and each reinforcing plate 15, etc. Since the number of welding points increases, there are problems in that workability during manufacturing is poor (and costs increase).

The present invention was made in view of the problems of the prior art described above, and the present invention can prevent welding distortion etc. from occurring on the rear plate.
The purpose of the present invention is to provide a counterweight that not only improves the overall appearance but also reduces the number of parts and welding points, and greatly improves workability during manufacturing.

[Means to solve the problem]

The feature of the configuration adopted by the present invention in order to solve the above-mentioned problems is that the rear plate is press-molded into a predetermined arc shape having an upper edge, a lower edge, and left and right side edges. However, each side edge of the rear plate constitutes each side plate, and the upper edge and lower edge of the rear plate constitute a part of the upper plate and the lower plate.

The rear plate may be formed by pressing a single rectangular flat plate into a predetermined arc shape.

Further, the rear plate may be formed by individually pressing a plurality of flat plate materials and joining them to form a predetermined arc shape.

[Effect]

With the above configuration, the rear plate is press-formed into a convex curved shape including the upper edge, lower edge, left and right side edges, and has a predetermined arc shape. The rigidity of the rear plate can be increased by bordering the lower edge and each side edge, and there is no need to weld a reinforcing plate or the like to the rear plate.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 5. In addition, in the example, the above-mentioned FIG. 6 and FIG.
Components that are the same as those of the prior art shown in the figures are given the same reference numerals, and their explanations will be omitted.

1 to 4 show a first embodiment of the present invention.

In the figure, reference numeral 21 indicates a counterweight provided at the rear of the upper revolving structure 2, and the counterweight 21 is similar to the counterweight 7 described in the prior art, with a front plate 22. Rear plate 23. Top plate 24A.

Although it is formed into a hollow structure from 24B, 24C (totally referred to as the top plate 24) and the bottom plate 25, the rear plate 23 of the counterweight 21 has an upper edge 23A and a lower edge 23B as shown in FIG. and left and right side edges 23
It is press-molded into a predetermined arc shape including C and 23C.

Here, the rear plate 23 is formed into a convex curved shape by pressing a rectangular steel plate, and its four
Around the upper edge 23A, lower edge 23B and each side edge 2
3C is integrally formed. And each side edge 23C
constitute left and right side plates of the counterweight 21, and their upper and lower ends are smoothly connected to the upper edge 23A and the lower edge 23B in a predetermined arc shape. Further, the upper edge 23A of the rear plate 23 is welded to the upper plate 24 so as to form a part of the upper plate 24, and the lower edge 23B is welded to the upper plate 24 so as to form a part of the upper plate 24.
5 and is welded to the lower plate 25 so as to form a part of the lower plate 25.

The counterweight 21 according to this embodiment has the above-mentioned configuration, and the manufacturing process thereof will be explained next.

First, a substantially rectangular steel plate is pressed to form the rear plate 23 into a predetermined arc shape, and the upper edge 23A, lower edge 23B, etc. 3 and the left and right side edges 23C, 23C are integrally formed. Then, both left and right ends of the front plate 22 are welded to the front end of each side edge 23C,
The lower plate 25 is welded to the lower edge 23B, and the upper edge 2
Weld the top plates 24A and 24B to 3A, and
The front plate 22 is welded to the front end of 24B and the lower plate 25.

Next, each screw member 16 is welded to the end face of the top plate 24A, 24E, and a counterweight 21 having a hollow structure is formed by leaving the central top plate 24C, and a weight adjustment material is placed inside the counterweight 21. Fill, then top plate 24
A top plate 24C is welded between A and 24B, and the top plate 24C is welded to each screw member 16 to seal the inside of the counterweight 21 to prevent rainwater from entering.

Thus, according to this embodiment, in order to integrally form the upper edge 23A, lower edge 23B, and side edges 23C on the rear plate 23 of the counterweight 21, the rear plate 23 is press-molded into a predetermined arc shape. , the rear plate 23 is attached to the upper edge 23A.
, the lower edge 23B, and each side edge 23C can be formed into a convex curved shape, and the rigidity of the rear plate 23 can be effectively increased. Further, the dimension B between the side edges 23C shown in FIG. 1 can be made uniform by press molding, and the overall dimensional accuracy can be improved.

Therefore, in this embodiment, by increasing the rigidity of the rear plate 23, it is possible to reliably prevent the rear plate 23 from being deformed by the load in the direction of arrow A shown in FIG.
The reinforcing plates 15 and the like used in the prior art can be made unnecessary, and welding distortion etc. can be prevented from occurring on the surface of the rear plate 23.

In addition, the upper edge 23A, the lower edge 23B, and each side edge 23
Since the rear plate 23 including C is press-formed into a predetermined arc shape, overall dimensional accuracy can be improved and mass production is possible. 23G can be formed with a rounded arc shape, which can solve problems such as injuring surrounding workers when the hydraulic excavator turns.

Furthermore, the side plates 13, 14, etc. used in the conventional technology can be eliminated, the number of welding points can be reduced, and grinder finishing etc. are no longer necessary, greatly improving workability during manufacturing and reducing costs. This has various effects, such as making it possible to achieve the desired goals.

Next, FIG. 5 shows a second embodiment of the present invention. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and their explanations will be omitted. The feature of this embodiment is that the rear plate 31 is individually press-molded from three flat plate materials.

This is because it is composed of right rear plates 32, 32 and a center rear plate 33.

Here, each of the rear plates 32 and 33 is formed into a predetermined shape by pressing a steel plate, and the left and right rear plates 32 have an upper edge 32A and a lower edge 32B, respectively.
and a side edge 32C are integrally formed, and the central rear plate 33 has an upper edge 33A and a lower edge 33B integrally formed.

The rear plate 31 is formed as shown in the figure by butt welding a central rear plate 33 between the left and right rear plates 32, 32.

Thus, even in this embodiment configured in this way, each side edge 32C of the rear plate 31 can constitute the left and right side plates of the counterweight, and the upper edges 32A and 33A constitute a part of the upper plate. , each lower edge 32B, 33
B can constitute a part of the bottom plate, and substantially the same effects as in the first embodiment can be obtained. In particular, in this embodiment, since the rear plate 31 is formed by three rear plates 32, 32, 33, the press die can be made smaller.

Not only can the same mold material be used as the press mold for the right rear plates 32, 32, but it can also be suitably employed when manufacturing a large counterweight.

In addition, in the second embodiment, the rear plate 31 was described as being composed of three rear plates 32, 32, 33, but instead of this, the rear plate can be formed from two rear plates to the left and right. It may be formed symmetrically, or it may be formed by dividing into four parts from four rear plates.

[Effects of the Invention] As detailed above, according to the present invention, the rear plate is formed into a predetermined arc shape including the upper edge, the lower edge, and the left and right side edges by press molding. Therefore, the rigidity of the rear plate can be increased, eliminating the need for reinforcing plates, etc., preventing welding distortion etc. from occurring on the surface of the rear plate, increasing the product value, and improving overall dimensional accuracy. , it is possible to improve workability during manufacturing by reducing the number of parts and welding locations. In addition, the rear plate can be divided into a plurality of parts and press-formed, resulting in various effects such as reducing the size of the press die and reducing costs.

[Brief explanation of drawings]

1 to 4 show a first embodiment of the present invention, FIG. 1 is a plan view of the counterweight, FIG. 2 is a front view of FIG. 1, and FIG. 3 is an arrow shown in FIG. 2. An enlarged cross-sectional view in the ■−■ direction,
FIG. 4 is a perspective view of the rear plate, FIG. 5 is a perspective view of the rear plate showing a second embodiment, FIGS. 6 to 10 show the prior art, and FIG. 6 is a perspective view of a hydraulic excavator. Fig. 7 is a plan view of the counterweight, Fig. 8 is a front view of Fig. 7, Fig. 9 is a left side view of Fig. 8, and Fig. 10 is an enlarged cross section in the direction of arrow XX in Fig. 8. It is a diagram. 21... Counterweight, 22... Front plate, 23
31... Rear plate, 23A, 32A, 33A... Upper edge, 23B, 32B, 33B... Lower edge, 23C13
2C...Side edge portion, 24...Top plate, 25...Bottom plate, 32.33...Rear plate.

Claims (3)

[Claims] (1) In a counterweight formed in a hollow structure by a front plate, a rear plate, a top plate, a bottom plate, and left and right side plates, and filled with a weight adjusting material, the rear plate has an upper edge portion, Press-molded to form a predetermined arc shape having a lower edge and left and right side edges, each side edge of the rear plate constitutes each side plate, and the upper edge of the rear plate 1. A counterweight, characterized in that the upper surface plate and the lower surface plate are partially constituted by the upper surface plate and the lower surface plate. (2) The counterweight according to claim 1, wherein the rear plate is formed into a predetermined arc shape by pressing a single rectangular flat plate. (3) The counterweight according to claim 1, wherein the rear plate is formed into a predetermined arc shape by individually pressing a plurality of flat plate materials and joining them together.