JPH0593660U - Welding structure of oil tank in construction machinery - Google Patents

Abstract

(57) [Summary] [Purpose] The environment in which construction machinery is used is harsh, and it is often subject to vibration. The vibration frequency and the natural frequency of the tank became close to each other and resonated, and a crack was generated in the weld penetration part a in a short time. An object of the present invention is to provide a welded structure that prevents the occurrence of this crack. [Structure] A slit is formed in the side wall plate 1a of a tank where a high concentrated stress is generated in a welded joint where the side wall plate 1b is abutted against the side wall plate 1a and joined by fillet welding.
In addition to fillet welding, slits are also welded.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a welding structure for an oil tank in a construction machine.

[0002]

[Prior Art]

 Conventionally, as shown in FIG. 1, the side wall plates 1a and 1b of the tank 1 are welded by the fillet weld 2 on one side. With this structure, stress concentrates on the weld penetration portion a, and thus cracks 3 occur on the side wall plate 1a side at this portion, which is a problem.

[0003]

[Problems to be solved by the device]

 The environment in which construction machinery is used is harsh, and it is often subject to vibration. A crack 3 was generated in the weld penetration part a in a short time because the frequency and the natural frequency of the tank became close to each other and resonated. An object of the present invention is to provide a welded structure that improves the welded structure and prevents the occurrence of cracks in a short time.

[0004]

[Means for Solving the Problems]

 In the welded joint where the side wall plate 1b is abutted against the side wall plate 1a of the tank and joined by fillet welding, a slit is provided on the side wall plate 1a where high concentrated stress occurs, and a slit part is formed outside the fillet weld. We also made welding.

[0005]

【Example】

 A description will be given based on FIG. 1a and 1b are side wall plates that constitute the tank 1 and are orthogonal to each other. The side wall plate 1a and the side wall plate 1b orthogonal thereto are joined by welding. In FIG. 2B, the symbol S is a slit provided in the side wall plate 1a. The slit S is provided in a range indicated by reference numeral 4 in FIG. 2A, that is, in a portion where a high concentrated stress is generated.

To weld and join the side wall plates 1a and 1b, first, the side wall plate 1b is abutted against the side wall plate 1a to perform fillet welding 2a. Then, the area 4 where the slit S is provided is welded 2b. Since the dimension d, that is, the dimension of the non-welded portion is reduced by performing the welding 2b on the slit S as described above, the stress concentration degree of the welded portion can be relaxed and the occurrence of cracks can be prevented.

In FIG. 3, the stress concentration rates before and after the improvement are obtained from the graph of FIG. Input data before improvement Input data after improvement B (thickness of sidewall member) 3.2mm 3.2mm d (depth of notch) 1.6mm 0.5mm 2θ (angle of notch) 0 0 ρ (notch R) ≈ 0 ≈ 0 d / B (depth of notch) 0.5 0.16 ρ / B 0.015 0.015 α (stress concentration rate) 6.3 4.25 Stress relaxation rate 100% 67. It is 5%, which means that stress relaxation of nearly 30% is possible.

[0008]

【effect】

 At the welded joint where the other side wall plate is abutted against the side wall plate of the tank and joined by fillet welding, a slit is provided in the side wall plate where high concentrated stress occurs, and also in the slit part outside the fillet weld. I tried to weld it. Since this is done, the size of the non-welded part is reduced and the stress concentration is relaxed, so that even if it is subjected to severe vibration, cracks 3 may occur in the weld penetration part a in a short time. It has become possible to extend the life of the tank significantly.

[Brief description of drawings]

1 shows an oil tank of a known construction machine, FIG. 1 (a) is a front view, FIG. 1 (b) is a sectional view taken along the arrow A in FIG. 1 (a), and FIG. 1 (c) is a welded portion. A graph showing the stress concentration.

2 shows an oil tank according to the present invention, FIG. 2 (a) is a front view, FIG. 2 (b) is a sectional view taken along the arrow B in FIG. 2 (a), and FIG. Graph showing concentration.

FIG. 3 is a graph showing the relationship between notch depth and stress concentration rate.

[Explanation of symbols]

 S Slit 1 Tank 1a, 1b Side wall plate 2 Fillet weld 2a Fillet weld 2b Weld 3 Crack 4 Slit area

Claims (1)

[Scope of utility model registration request] 1. A welded joint portion in which a side wall plate (1b) is abutted against a side wall plate (1a) of a tank and joined by fillet,
Slit (S) on side wall plate (1a) where high concentrated stress occurs
A welding structure for an oil tank in a construction machine, characterized in that the slit portion is welded to the outside of the fillet weld and is joined.