Drum of brake car VAZ-2108

Contents

1. PROCESS PART

1.1 Analysis of operating conditions and possible faults of the part

1.2 Determination of limit values of defects of parts

1.3 Selection of rational methods of parts repair

1.4 Determining the Optimal Part Recovery Sequence

1.5 Design Cleaning and Washing Operations

1.6 Design of defective operations

1.7 Design of repair workpiece receiving operations

1.8 Design of operations for obtaining a suitable part from a repair workpiece

1.9 Preparation of technical documentation

2. DESIGN PART

2.1 Selection of fixture type and diagram

2.2 Calculation of clamping force

3. TECHNO-ECONOMIC PART

CONCLUSION

LIST OF LITERATURE USED

APPLICATION

1. process part

1.1 Analysis of operating conditions and possible faults of the part

Brake systems are used to reduce the speed and complete stop of the car, as well as to keep the stationary car in place. Braking systems installed on cars should be as effective as possible when braking with different loads and at different speeds. Also, braking mechanisms should ensure braking of the car regardless of external conditions.

Friction braking mechanisms have become most widespread, in which braking occurs due to friction forces arising between rotating and stationary parts. A drum brake mechanism is a mechanism in which friction forces arise due to the pressing of fixed shoes to the inner surface of the rotating cylinder of the brake drum. The main possible faults are debris, cracks, gouges appearing between the friction surfaces, as well as annular grooves or wear of the working surface.

1.2 Determination of limit values of defects of parts

According to the "Repair Manual," as well as practical experience of operation, the cylinders of the brake drums are restored when deep hairlines, burrs, as well as an annular groove formed over time as a result of contact of the cylinder with the brake pad are detected on the working surface of the cylinder. As practical experience shows, with the further operation of brake drums, the appearance of fragments and cracks of the cylinder is possible. As a result of the appearance of the annular groove, the contact area of the brake linings with the cylinder area is reduced and, as a result, the braking efficiency of the car decreases, which can lead to negative consequences.

According to the technical data, the maximum permissible diameter of the drum is 201.5 mm, otherwise its strength is violated.

1.3 Selection of rational methods of parts repair

Currently, quite a few methods of restoring parts are known. Repair of the working surface of the cylinder can be carried out in the following ways:

a) in case the drum diameter does not exceed the maximum permissible size - mechanical machining (boring);

b) if the measures taken are insufficient or the diameter of the working surface has already exceeded the maximum permissible value, then the following methods are recommended: cutting the cylinder out of the brake drum and pressing a new one, surfacing, gas-thermal spraying.

After the material layer is applied, the surface is treated to the desired size.

The most widely used in the restoration of automotive parts were various types of locksmithing. These include locksmithing itself, mechanical processing related to the preparation of the part for coating and processing after their application, processing of parts for repair size, supply of additional repair parts.

Surfacing is the most common way to restore a part. It is intended for coating to compensate for wear of surfaces. Sputtering, as a method of restoring parts, is based on the application of sprayed metal to worn out surfaces of parts.

Depending on the method of melting the metal, there are different types: electric arc, high-frequency, plasma detonation and others. We will not consider cutting the cylinder out of the brake drum and pressing the new one, since there is a replacement for the failed part. In this work, we will suggest that the diameter of the brake drum in the depth of the annular groove exceeds the maximum permissible values ​ ​ (201.5 mm). In this case, it is not possible to get rid of the defect only by stretching. Therefore, as a repair method, we choose to spray an additional layer of metal in order to compensate for wear of the working surface and subsequent machining.

1.5 Design Cleaning and Washing Operations

005. During the operation of the car, deposits accumulate in large quantities on the outer surfaces of the brake drum. In these cases, the cleaning can be carried out by immersion. OM4267 washer is used for this purpose. The unit is designed for washing assembly units and parts using synthetic washing agents. Washing in inkjet washing machines using appropriate detergents does not provide the proper degree of cleaning from deposits. In this regard, parts with deposits are cleaned in baths.

For dip cleaning, Labomid203 or MS-8 with a concentration of 2030 g/l is used as detergents. Operating temperature of solutions is 80100 0С. Caustic soda is used to improve detergent properties. We take the norm of time for washing T0 = 26 hours.

2.1 Selection of fixture type and diagram

An accessory is a device that creates the necessary conditions and convenience for performing technological operations. Devices are divided into four groups according to the intended purpose.

1. Disassembly and assembly devices - designed for disassembly and assembly of units and assemblies. In our cases, the brake drum is removed from the wheel hub using light tapping of a wooden hammer along the inner edge of the drum, or using a special removable device.

2. Machine tools - for installation and fixation of machined parts relative to cutting tool. In order to process the brake drum on the machine, it is necessary to make a special accessory, the drawing of which is given on sheet 1 of the graphic part.

On this side, the brake drum is attached, on the other side of the device it is inserted into the chuck of the machine.

The mounting base for the brake drum is a center hole. In order to prevent the drum from breaking off the device, it is clamped by a special nut of the graphic part shown on sheet 3.

3. The test accessory is used to check the repair results. In ours cases as control adaptation serves the caliper for check of internal diameter of a cylinder of ShTs1 with a limit of measurements of 250 mm and also the indicator of hour type for check of radial beating (GOST 57768). Radial run-out of drum is not more than 1.5 mm.

Conclusion

We conducted a full analysis of the operating conditions of the brake drum, possible malfunctions, as well as rational repair methods. We determined the optimal sequence of operations to restore the performance of the brake drum and compiled technological and operational maps.