JPH0510049Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to an undercarriage used in construction machinery such as a hydraulic excavator, and in particular, to an undercarriage of a construction machine that is designed to increase the strength of the round body. Regarding the body.

[Prior art]

4 to 8 show a hydraulic excavator as an example of an undercarriage of a construction machine according to the prior art.

In the figure, reference numeral 1 indicates an undercarriage, and the undercarriage 1 includes a truck frame 2 consisting of a round body 13, each leg frame 16, and each side frame 19, which will be described later. A pair of left and right traveling devices 3, 3 provided on the end side, and a pair of left and right crawlers 4, which are driven by the respective traveling devices 3 via sprockets 3A, 3A to cause the vehicle to travel. It is roughly composed of 4. 5 is a turning wheel 6 on the lower traveling body 1
The upper revolving body 5 is comprised of a machine room 7, a driver's cab 8, a counterweight 9, etc. provided on an upper frame 5A, and the upper frame 5A is rotatably mounted on an upper frame 5A. It is fixed to the outer ring side of the ring using bolts or other means. A working device 10 consisting of a boom, an arm, and a bucket is provided at the front of the upper frame 5A.
is provided.

On the other hand, the machine room 7 of the upper revolving body 5 is provided with an engine and a hydraulic pump 7A as a hydraulic pressure source driven by the engine.
Each traveling device 3, working device 10, etc. are driven by pressure oil from the vehicle. 11,1
1, ... are hydraulic pipes for supplying pressure oil from the hydraulic pump 7A to each traveling device 3, and each hydraulic pipe 11 is connected to the swing ring 6 and the round via a center joint 12 and a pipe hole 14A, which will be described later. It is inserted into the barrel 13, and both ends thereof are connected to the hydraulic pump 7A and each traveling device 3, respectively. Reference numeral 12 denotes a center joint provided in the middle of each hydraulic pipe 11. The center joint 12 is located on the central axis of the swing ring 6, and the center joint 12 is located on the central axis of the swing ring 6, and the center joint 12 is located on the center axis of the swing ring 6, and the center joint 12 is located on the center axis of the swing ring 6. A hydraulic pump 7 is attached to each traveling device 3.
Pressure oil can be supplied from A.

Next, the track frame 2 of the undercarriage 1 will be described in detail with reference to FIG.

In the figure, 13 indicates a circular body, and the circular body 13 consists of a lower circular body 14 and an upper circular body 15 formed into a cylindrical shape from a plate material having a predetermined wall thickness, and the upper circular body 15, An upper flange 16C, which will be described later, is arranged between the lower cylinders 14. And the upper round body 1
5, the inner ring side of the swing ring 6 is fixed using means such as bolts, and the upper frame 5A of the upper swing body 5 is mounted on the cylinder 13 via the swing ring 6 so that it can turn. It's summery. Further, piping holes 14A are bored in the lower cylinder 14 in the radial direction at positions closer to the respective traveling devices 3, and the piping holes 14A allow the hydraulic pipes 11 to be inserted between the inside and outside of the cylinder 13. It's becoming like that.

16, 16, . . . are left and right legs whose base ends are joined to the cylinder 13 by means such as welding, and which extend from the cylinder 13 to the left and right in a substantially X-shape. Each of the leg frames 16 has front and rear webs 16A made of four plates, each of which has its base end joined to the outer peripheral surface of the lower cylinder 14 and its distal end joined to each side frame 19, which will be described later. ,16B
and upper and lower flanges 16 each formed from a single sheet of plate material in a substantially X-shape and joined to the upper and lower ends of each of the front and rear webs 16A, 16B, respectively.
C, 16D. The base end side of the upper flange 16C is disposed between the upper cylindrical body 15 and the lower cylindrical body 14, and the welded portion 1 shown in FIG.
7, 17, . . . are connected to the lower end of the upper cylinder 15 and the upper end of the lower cylinder 14, respectively. Further, each tip of the upper flange 16C is joined to each side frame 19. On the other hand, the base end side of the lower flange 16D is the welded part 1 shown in FIG.
8 and 18 to the lower end of the lower cylinder 14, and each tip is joined to each side frame 19. Further, large diameter holes 16E, 16F are bored in the centers of the base ends of the upper and lower flanges 16C, 16D.

Reference numerals 19 and 19 denote side frames that are joined to the distal end side of each leg frame 16 using means such as welding. Guide wheel support brackets 20, 20 are provided. and,
Support brackets 21, 21 are provided at the rear of each side frame 19 for supporting each traveling device 3.
are provided, and each traveling device 3 is attached to each support bracket 21 as shown in FIG.

22 is the lower cylinder 14 by drilling the piping hole 14A.
The reinforcing plate 22 is a reinforcing plate to compensate for the decrease in strength of the lower cylinder 14, and the reinforcing plate 22 is formed of a thick plate material curved with a curvature corresponding to the lower cylinder 14, as shown in FIGS. 7 and 8. A hole 22A communicating with the piping hole 14A is bored in the center. The reinforcing plate 22 is located between the base end sides of each of the front webs 16A and between the upper and lower flanges 16C and 16D,
It is fixed to the outer peripheral surface of the lower cylinder 14 by welding. Here, the inner surface of the reinforcing plate 22 is the welded portion 2
3 around the piping hole 14A of the lower cylinder 14, and the outer surface is connected to the lower cylinder 1 by a welding part 24.
4. They are joined to the base end sides of the upper and lower flanges 16C, 16D and each front web 16A.
Furthermore, in the figure, 25 is a welded part of the lower cylinder 14;
6 and 26 are the base end of each front web 16A and the lower round body 1
The welded parts with 4 are shown respectively.

The hydraulic excavator according to the prior art has the above-mentioned configuration, and when the hydraulic excavator is run, pressure oil from the hydraulic pump 7A in the machine room 7 is supplied to each traveling device 3 via each hydraulic pipe 11. Each crawler track 4 is driven to travel by each traveling device 3. Further, when performing shovel work or the like using the working device 10, pressure oil is supplied to each cylinder (not shown) of the working device 10 to operate a bucket, an arm, etc.

By the way, in the above-mentioned prior art, the track frame 2 serving as the main body frame of the lower traveling body 1 is constituted by the round body 13, each leg frame 16, and each side frame 19, and the turning wheel 6 is provided on the round body 13. Since the upper revolving body 5 is rotatably mounted through the upper revolving body 5, the loads of the machine room 7, operator's cab 8, counterweight 9, working device 10, etc. provided on the upper frame 5A of the upper revolving body 5, Furthermore, all loads applied from the outside during operation of the working device 10 act on the cylinder 13. On the other hand, since the lower cylinder 14 of the cylinder 13 is provided with piping holes 14A for inserting each hydraulic pipe 11 between the inside and outside of the cylinder 13, the strength of the cylinder 13 is increased by the lower cylinder 14. Piping hole 1
It decreases near 4A.

Therefore, in the prior art, in order to form the cylindrical body 13 with high strength, a reinforcing plate 22 is used near the piping hole 14A of the lower cylindrical body 14, and the reinforcing plate 22 is attached to the lower cylindrical body 14.
4. The vicinity of the piping hole 14A is reinforced by joining the upper and lower flanges 16C, 16D and the base end of each front web 16A with welded parts 23, 24.

[Problem that the invention attempts to solve]

However, in the prior art described above, since the inner and outer surfaces of the reinforcing plate 22 are joined to the lower cylinder 14, the upper and lower flanges 16C, 16D, and each front web 16A by the welded parts 23 and 24, welding is not required. There are disadvantages in that not only does the area increase and the amount of bonding material (welded metal) increases, but also the welding work becomes complicated and it is difficult to automate the welding work. In addition, since the thick reinforcing plate 22 is used, the welding radius of the welded portion 24 must be increased, which complicates the welding work and makes welding defects more likely.

Furthermore, since the reinforcing plate 22 is simply superimposed on the outer periphery of the lower cylindrical body 14 and its periphery is joined by the welded parts 23 and 24, the welded part 2
Stress tends to concentrate near 3 and 24, which has the following drawbacks.

That is, all the vibrations and loads during shovel operation and running act between the lower cylinder 14 and each front web 16A, causing bending, twisting, and shearing in the directions of arrows A and B shown in FIG. Since complex loads such as
4 has the disadvantage that cracks 27, 28, etc. are likely to occur near the welds 23, 24 due to stress concentration. In this case, even if the reinforcing plate 22 is formed wider than the interval between the proximal ends of each front web 16A and the proximal end of each front web 16A is directly joined to the reinforcing plate 22, the cracks 27, It is difficult to prevent the occurrence of 28 etc.

The present invention was developed in view of the above-mentioned drawbacks of the prior art.The present invention can reduce the welding area and welding warp, prevent the occurrence of welding defects, and simplify and automate the welding work. Furthermore, it is an object of the present invention to provide an undercarriage for a construction machine in which the strength of the cylindrical body is improved and the occurrence of cracks, etc. can be prevented.

[Means for solving problems]

The feature of the means adopted by the present invention in order to solve the above-mentioned problems is that the round body is formed wider than the distance between the base ends of the front webs of each leg frame located closer to the traveling device side, and the piping holes are a thick ring portion with a hole formed therein, and a thinner wall than the thick ring portion;
It is comprised of a thin ring part which forms a cylindrical body together with the thick ring part, and the proximal end side of the front web of each of the leg frames is joined to the thick ring part.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 3. In the embodiment, the same components as those of the prior art shown in FIGS. 4 to 8 described above are designated by the same reference numerals, and the explanation thereof will be omitted.

In the figure, numeral 31 indicates a lower cylinder used in this embodiment in place of the lower cylinder 14 described in the prior art, and the lower cylinder 31 and the upper cylinder 15 constitute the cylinder 13. Here, the lower cylinder 31 is connected to each traveling device 3.
A thick ring portion 31B is formed wider than the proximal distance of the front web 16A of each leg frame 16 located on the side, and has a piping hole 31A drilled in the center.
and is formed thinner than the thick ring portion 31B,
It consists of a thin ring part 31C forming a cylindrical body together with the thick ring part 31B. It is formed by twisting. Further, the thick ring portion 31B is formed of a thick plate material having a strength approximately corresponding to the total thickness of the reinforcing plate 22 and the lower cylinder 14 used in the prior art, Thin ring part 31C
It is also curved with a curvature corresponding to .

Both sides 31D, 31D in the width direction of the thick ring portion 31B are chamfered on the outer peripheral surface side and formed into a tapered shape, and both ends thereof are connected to the welding portions 32, 31D.
2 are joined to both ends of the thin ring portion 31C in abutting state (see FIG. 2). Also,
The thick ring portion 31B has a welded portion 33 on the outer circumferential surface at a position inside the widthwise both sides 31D, 31D.
33 to the base end side of each front web 16A, and the base end side of each rear web 16B is joined to the thin ring portion 31C. On the other hand, thick ring part 3
1B, the upper and lower ends of the thin ring part 31C, that is, the upper and lower ends of the lower cylinder 31 are connected to the upper flange 1 by welding parts 34, 34, 35, and 35, respectively.
6C and the lower flange 16D (see FIG. 3).

The piping holes 31A are located closer to each traveling device 3 side and are bored in the radial direction of the thick ring portion 31B, so that each hydraulic piping 11 is inserted between the inside and outside of the lower cylinder 31. ing. Although FIG. 1 shows the rear side of the truck frame 2 and omits the front side, each leg frame 16 has two pairs on the left and right sides of the round body 13, as shown in FIG. The front and rear webs 16A, 16 of each leg frame 16 extend in a substantially X shape and are located on the front side.
B is a thin ring portion 3 with a lower circular body 31 on the proximal end side, similar to each of the webs 16A and 16B shown in FIG.
1C, and the tip side is connected to each side frame 19.
is joined to.

This embodiment has the above-mentioned configuration, and there is no particular difference in its basic operation from that of the prior art.

However, in this embodiment, a thick ring portion 31B having a piping hole 31A formed in the center of the lower cylinder 31 is used.
The welding portions 3 are formed thinner than the thick ring portion 31B, and each welding portion 3 is formed at both ends of the thick ring portion 31B.
2, and the thick ring part 31B is formed wide, and each front web 1 is attached to the thick ring part 31B.
Since the base end side of 6A is joined by each welding part 33, each welding part 32, 3 shown in FIGS. 2 and 3
As shown in Nos. 3, 34, and 35, the welding area and welding burr can be significantly reduced compared to the prior art, and the occurrence of welding defects can be prevented. And each welding part 32,3
Since the shapes of 3, 34, and 35 can be simplified, welding work can be simplified and automation can be easily achieved.

Further, the thick ring portion 31B is formed wide from a thick single plate material, the piping hole 31A is bored in the thick ring portion 31B, and the proximal end side of each front web 16A is connected to each welding portion 33. Since the thick ring part 31B is joined to the thick ring part 31B by the thick ring part 31B, the complicated vibrations and loads that act between the lower cylinder 31 and each front web 16A during shovel work or traveling are absorbed by the thick ring part 31B.
This eliminates stress concentration near the welded portions 23 and 24 of the reinforcing plate 22 as in the prior art, and prevents the occurrence of cracks and the like.

Therefore, in this embodiment, the strength of the lower cylinder 31 can be reliably improved, and the entire cylinder 13 together with the upper cylinder 15 can be formed to have high strength.

In addition, in the above embodiment, the lower cylinder 31 was described as being formed separately from the upper cylinder 15, but
Thin ring part 31C of lower cylinder 31 and upper cylinder 1
5 may be integrally formed, and the thick ring portion 31B of the lower cylindrical body 31 may be joined to these.
In this case, the upper and lower flanges 16C and 16D may be joined to the outer peripheral surface of the cylinder 13.

Furthermore, although the above embodiments have been described using a hydraulic excavator as an example, the present invention is not limited thereto, and may be applied to an undercarriage of a construction machine other than a hydraulic excavator.

[Effect of idea]

As described in detail above, according to the present invention, a thick ring portion in which piping holes are bored is provided on the cylinder body, and the thick ring portion is attached to the front web base of each leg frame located closer to the traveling device side. Since the width is formed wider than the end side spacing and the base end side of each front web is joined to the thick ring part, it is possible to prevent the strength near the piping hole from decreasing and to reduce stress concentration. It is possible to reliably improve the strength of the cylinder. Furthermore, the welding area and welding burr can be reduced, welding defects can be prevented from occurring, welding work can be simplified, and welding work can be automated.

[Brief explanation of the drawing]

Figures 1 to 3 relate to embodiments of the present invention,
Figure 1 is a horizontal sectional view showing the main parts of the undercarriage, Figure 2 is an enlarged cross-sectional view of the main parts in Figure 1, and Figure 3 is a cross-section in the direction of the arrow in Figure 2. figure,
4 to 8 relate to the prior art, FIG. 4 is an external view of a hydraulic excavator, FIG. 5 is a sectional view in the direction of the arrow in FIG. 4, and FIG. 6 is a truck shown in FIG. 5. A perspective view of the frame, FIG. 7 is a horizontal cross-sectional view showing an enlarged main part of FIG. 6, and FIG. 8 is a cross-sectional view in the direction of the arrow in FIG. 1... lower running body, 2... truck frame,
3...Traveling device, 4...Crawler track, 5...Upper rotating body, 6...Swivel ring, 7A...Hydraulic pump, 10...
... Working equipment, 11 ... Hydraulic piping, 12 ... Center joint, 13 ... Round body, 15 ... Upper round body,
16...Leg frame, 16A...Front web, 1
6B...Rear web, 16C...Upper flange, 16
D...Lower flange, 19...Side frame, 3
1... Lower cylinder, 31A... Piping hole, 31B...
Thick ring part, 31C... Thin ring part, 32,
33, 34, 35...Welding part.

Claims (1)

[Scope of utility model claims] A cylindrical body on which an upper rotating body can be mounted via a turning ring, and left and right legs that are made up of front and rear webs and upper and lower flanges, and whose base ends are joined to the body. a left and right side frame connected to the tip side of each leg frame, a traveling device provided on one side of each side frame, and a hydraulic power source of the upper revolving body. An undercarriage of a construction machine comprising a hydraulic piping for supplying pressure oil to the device, and a piping hole drilled in the radial direction of the cylinder to insert the hydraulic piping between the inside and outside of the cylinder. , the circular body includes a thick-walled ring portion that is formed wider than the distance between the base ends of the front webs of the leg frames located closer to the traveling device side, and in which the piping hole is bored; The thin ring part is thinner than the thick ring part and forms a cylindrical body together with the thick ring part, and the base end side of the front web of each leg frame is joined to the thick ring part. An undercarriage body of a construction machine characterized by: