Two Hitachi Excavators of a company are the second-hand machines purchased, mainly used for the clearing of the cleaning of bulk goods such as fertilizers. When they start, the car is not good, and the track is often falling off, and the average of 50,000 tons of fertilizer per unloaded. The track is to fall off for more than 10 times, which seriously affects normal production. At present, one of the excavators of the excavator has been bent and deformed, and cracks are crackdown, and they are still ineffective. After research, it decided to improve the track tensioned hydraulic cylinder.
1. Status of crawler tensioning hydraulic cylinder
As can be known from Fig. 1-12, the hydraulic cylinder is fixed to the vehicle chassis frame by the card station 7, but the butter self-injection is injected, and the cylinder into the cylinder, but the butter is urged to push the plunger 2 ( The plunger head has three oil seals), and the outer end of the plunger is on the front wheel bracket 1, the bracket boom has a front wheel extension, increasing the spacing of the front and rear wheels, thereby achieving the purpose of tensioning track. If the track is too tight, the large nut at the oil opening can be rotated, and some butter can be released. Spring outside the cylinder is used to buffer the impact load.
Because the machine is used for second-hand machinery, the technical information is not complete. At the same time, the crawler tensioning hydraulic cylinder that is damaged on the machine is the trap tensioning hydraulic cylinder on the original car, and the original cushion spring in the cylinder is formed. A portion has been broken, so the current spring is shorter than the original. From the structural view, the hydraulic cylinder is elongated and difficult to process: the total length of the hydraulic tank is 627mm, the outer diameter is small, the interior is hollow, the cylinder wall is thin, the overall rigidity is poor: the level of horizontal impact to the hydraulic cylinder is very high.
2. Improvement schemes and effects
It can be seen from the above analysis that the track tensioning hydraulic cylinder is unreasonable in the design, and the length or increase the axial diameter as much as possible, but the total length of the hydraulic cylinder is not changed by external conditions. I want to find a way.
(1) Design the hydraulic cylinder to design the hydraulic cylinder, and the members A and Parts B are separately processed, and the member B is loaded into A, and three oil seals are increased in the handover to prevent butter leakage. In order to ensure the coaxial degree, the length of the joint is determined to be a 70 mm material using 40Cr.
(2) The pad 6 is applied to the right side of the card 7 to shorten the distance from the hydraulic cylinder to the coach station, so that the spring can make full buffering effect.
After the split structure is changed, the joint portion is 70 mm, and if the radial partition is only active on a segment of 70 mm long, the force is equalized. At the same time, the spring buffer capacity is enhanced after the pad, even when the spring buffer cannot be encountered, the members A and Parts B can move relative to the soleness of the hydraulic cylinder.
After the improved excavator has been continuously unloaded, the tensioning hydraulic cylinder has a good performance, ensuring the normal operation of the track, and set up a port loading and unloading of 56,000 tons of fertilizers in 10 days.
