T-130 caterpillar link recovery project

Introduction

During the operation of the car, its reliability and other properties are gradually removed as a result of wear of the parts, as well as corrosion and fatigue of the material from which they are made. Various faults appear in the car, which are eliminated during maintenance and repair.

Overhaul of cars is of great economic and, therefore, national economic importance. The main source of economic efficiency of overhaul of cars is the use of the residual resource of their parts. About 7079% of car parts that have passed the service life before the first overhaul have a residual life and can be reused either without repair or after a slight repair impact. It is known from repair practice that most parts rejected by wear lose no more than 1-2% of the original mass. At the same time, the strength of the parts is practically preserved. For example, 95% of the parts of internal combustion engines are rejected with wear not exceeding 0.3 mm, and most of them can be reused after recovery.

From the point of view of material-intensive reproduction of machines, economic

the feasibility of repair is due to the possibility of reuse of most parts, both suitable and extremely worn out after restoration. This makes it possible to carry out repairs in a shorter time with lower costs of metal and other materials compared to the costs of manufacturing new machines.

The high quality of repaired cars and units places increased requirements on the resource of restored parts. It is known that in cars and units after overhaul, the parts work, as a rule, in significantly worse conditions than in new ones, which is associated with a change in the basic dimensions, displacement of the axes in the body parts, a change in the lubrication supply conditions, etc. In this regard, part repair technologies should be based on coating and post-treatment methods that would not only preserve, but also increase the life of repaired parts. For example, when restoring parts by chromium, plasma and detonation spraying, induction and laser surfacing, contact welding of a metal layer, their wear resistance is significantly higher than that of new ones.

All parts from cars entering the overhaul can be divided into three groups. The first group includes parts that have completely exhausted their resource and should be replaced by new ones when repairing a car. The number of such parts is relatively small and is 2530%. Parts of this group include pistons, piston rings, bearing inserts, various bushings, rubber products, etc.

The second group of parts, which reaches 3035%, are parts whose resource allows them to be used without repair. This group includes all parts whose working surface wear is within acceptable limits.

The third group includes the remaining parts of the car (4075%). These parts can only be reused after they have been restored. This group includes most of the most complex and expensive basic parts of the car. In particular, cylinder block, shaft, block head, gearbox and rear post, camshaft, etc. The cost of restoring these parts does not exceed 1015% of the cost of their manufacture.

That is, the main source of economic efficiency of car overhaul is the use of the residual resource of the car parts of the second and third groups.

Restoration of caterpillar links

The caterpillar is an element of the undercarriage of cars. The link of the caterpillar chain in section is an even number of ellipses, the links of the chain form a helical line. The wear resistance resulting from the reduction of friction parts, the high adhesion coefficient makes it promising to use the caterpillar not only in terrestrial conditions, but also in conditions of other planets that have different gravitational characteristics and soil properties.

Links of caterpillar webs are rejected primarily due to wear of holes of links in connection with finger. Metal losses for this wear from the total weight of the link are not more than 4%. Further, wear of the treadmill, wear of the surface for the bolts of the shoe and wear of the surface for the sleeve are most common.

Design part

Select Recovery Plan

005 Boring

1. Attach the workpiece to the clutches

2. Bore hole with diameter 64.85 mm to diameter 65.25 mm by length L = 15 mm

3. Bore 44.32 mm diameter to 44.75 mm diameter by length L = 35 mm

010 Surfacing

1. Attach the workpiece to the clutches

2. Brew wear surface for length L = 235 mm

015 Milling

1. Attach the workpiece to the clutches

2. Mill size 125 mm to size 123 mm by length L = 235 mm

020 Drill

1. Attach the workpiece to the clutches

2 . Drill 2 holes with diameter 20.20 mm to diameter 21.20 mm by length L = 23.00 mm

025 Control

1. Perform control measurements of the part for compliance with the drawing dimensions