Diploma project for the repair of the rear suspension of the GAZ car

Contents

CONTENTS

Introduction

Main part

Design of diesel fuel equipment repair area

engine

1 Technical justification of the project

1.1 Calculation of initial project standards

1.2 Correction of maintenance periodicity

1.2.1 Correction of frequency of TO-

1.2.2 Correction of frequency of TO-

1.3 Selection and calculation of inter-repair mileage standards

1.4 Selection and calculation of factors for adjustment of norms

labor inputs

1.5 Calculation of labour intensity

1.6 Calculation of car downtime during maintenance and overhaul

1.7 Calculation of relative operating factors of the post

1.7.1 Calculation of technical readiness factor of vehicles

1.7.2 Calculation of the utilization rate of serviced vehicles

1.8 Calculation of annual mileage and quantity of maintenance for the year

2 Feasibility study

2.1 Calculation of labour intensity

2.1.1 Calculation of annual labor intensity of works for TO-

2.2.2 Calculation of annual labor intensity for TO-

2.2.3 Calculation of annual labor consumption for the current repair

2.2.4 Determination of the share of labor intensity of the department, post

2.2 Determination of minimum number of working posts

2.3 Calculation of the minimum production area of the post

2.4 Selection and name of equipment, instruments, tools and

accessories to the designed post

2.5 Purpose of test bench for shock absorber

2.5.1 Purpose of the bench

2.5.2 Bench Arrangement

2.5.3 Shock absorber diagnostics process

2.5.4 Most Characteristic Faults

2.5.5 Process of removal shock absorber diagnostics

2.5.6 Shock absorber arrangement

2.5.7 Analysis of suspension types

2.5.8 Analysis of suspension failures

3 Occupational safety and safety

3.1 Safety requirements when performing the main types of works

3.2 Lighting of the site

3.3 Site Safety

3.4 Fire safety

3.5 Production sanitation

3.6 Fire safety of electrical section

4 Economic justification of the project

4.1 Calculation of the number of employees in the workshop of an automobile enterprise

4.2 Calculation of the value of fixed assets

4.3 Payroll Calculation

4.4 Shop expenses

4.5 Calculation of cost of repair works

Conclusion

List of sources used

Applications

Annex A. Certificate project statement

Introduction

Automotive industry and automotive repair production are designed to meet the growing need of the national economy for cars, units and parts.

Thanks to the repair, the service life of cars is significantly increased. The volume of traffic accounted for by overhauled cars accounts for 3040% of the total volume of cargo transported by cars and will increase further in the future. Repair of cars and tractors is an objective necessity, which is due to technical and economic reasons.

Firstly, the needs of the national economy in cars are partially met through the operation of repaired equipment.

Secondly, repair ensures the further use of those elements that are not completely worn out. As a result, considerable productivity remains.

Thirdly, repairs contribute to saving materials spent on the manufacture of new pieces of equipment. When recovering, metal consumption is 2030 times lower than when manufacturing.

The cost of maintaining the operability of equipment and units is many times higher than their initial cost. Each year, money is spent on each car in the amount of 25 specialization of car repair production; improvement of technical level and technical discipline of automotive repair production on the basis of realization of technological and organizational continuity of automotive industry and repair ensuring technological formation of repaired car and its components in strict compliance with requirements of State standards and other regulatory and technical documentation; Expansion of research and development activities that accelerate the pace of technical progress in car repair and the best use of all types of resources; systematic reduction of costs for all types of repairs due to constant improvement of the design of cars in the direction of increasing their durability, reliability and repairability; improvement of the organization and technology of car maintenance through the cooperation of motor transport enterprises with repair enterprises; improving training of personnel, including mechanical engineers and process engineers of automotive repair production.

Car repair production is dynamic in nature. The ever-increasing need for car repairs, progressive changes in their design require the improvement of repair equipment and repair technology during the inspection of the car by the duty mechanic at the checkpoint upon returning the car from the line;

at the first or second maintenance of cars - mechanic or foreman.

Faulty units, units and devices removed from the car are transferred (through an intermediate warehouse) to the corresponding production areas, where they are exchanged for serviceable ones. The site manager determines the nature and scope of repairs.

The units are handed over for overhaul in accordance with the current specifications for cars and units being handed over for repair. Units are accepted from overhaul after their testing on stands in accordance with specifications for cars and units accepted from repair.

Modern car suspensions are complex designs that combine mechanical, hydraulic, pneumatic and electrical elements, can have electronic control systems, which allows you to obtain high parameters of comfort, controllability and safety.

The main criterion for the safety of the suspension can be considered to ensure good coupling qualities of tires with the road. Car suspension, or compression system - a set of parts, units and mechanisms that are a connecting link between the car body and the road surface.

The reduction of the level of fluctuations in the body and wheels of cars (improving the smoothness and stability of movement) is constantly paid great attention. When designing cars, the process of their movement in different road conditions, with different speeds and loads is first simulated, then the results of the calculations are checked by testing cars on the corresponding stands, in road conditions. For mathematical modeling, parameters of elastic and damping suspension devices are required, to which the characteristics of shock absorbers [1] also belong.

This is a hydraulic mechanism placed, as well as a spring, between the sprung and unsprung mass of the car. The purpose of the shock absorber is to convert the kinetic energy of the suspension movement received from the irregularities of the road into potential energy. In other words, the shock absorber converts the vertical vibrations of the vehicle body into heat, which is then released into the environment. When designing the suspension, they try to select such a place for installing the shock absorber to ensure good heat removal through incoming air when driving the car.

During operation, the suspension parts of the car wear out. First of all, shock absorbers lose their performance. On the recommendation of the US Automobile Council, check the performance of shock absorbers after 40 thousand miles (approximately 64,400 km), and then every 10 thousand miles (16,000 km) under normal operation. Such attention to shock absorbers is not accidental. Their wear and tear is inconspicuous to the driver and usually manifests itself in critical situations. The traction of the wheels with the road is reduced, and the driver cannot properly realize the capabilities of the car. In turns, the car may not maintain a predetermined direction of movement, and in addition, the braking distance is extended.

The test equipment for shock absorbers shall be subject to the following requirements:

- the stand shall perform fast, serial and reproducible tests;

- when testing, the shock absorber piston shall reach the speeds that are usual under the actual operating conditions of the vehicle; provide measurable values that can be compared in functionality with those of a new vehicle damper installed according to the manufacturer's instructions and allow an assessment of the damper condition based on standard conditions;

- Provide measured values that are not affected by different types of tyres.

In the final qualification work, a dynamic method of testing shock absorbers will be considered.

Relevance of the topic: since the undercarriage repair area is an integral part of any workshop. Improving the quality of work, using modern diagnostic methods and using modern equipment increases the resource of units and saves the resources of the enterprise.

The main task of the diploma project is: Development of the technological process of repairing the chassis of the GAZ car.

The purpose of the diploma project is: Design of the car suspension repair and inspection area.

Shock absorber diagnostics process

Diagnosing the technical condition of shock absorbers is of paramount importance. Their serviceability depends on traffic safety, fuel efficiency, tire service life and the durability of a number of units and mechanisms of the car.

The suspension of the car is a unit responsible for damping the irregularities of the road surface when driving, the comfort of the ride primarily depends on its condition, which is of paramount importance for transport. Also, the suspension, absorbing irregularities, contributes to lower dynamic overloads of all suspension units and assemblies as a whole, reduces the risk of damage to the bridge beam, and the occurrence of fatigue cracks. Of great importance is the comfort of the trip, which is provided by damping of oscillations, which is provided by serviceable shock absorbers.

In the practice of modern maintenance, devices for diagnosing suspension elements began to be used relatively recently, mainly shock absorber control systems.

For the automobile, the parameters determining the operating state of the shock absorber are:

1 vibration attenuation amplitude;

2 operating stroke of shock absorber;

3 amplitude of body oscillations during suspension operation (during diagnostics of shock absorber installed on the car);

4 horizontal movements of the suspension body (when diagnosing the shock absorber installed on the car).

Taking into account all these parameters, it is possible to draw conclusions about the general technical condition of the shock absorber, which is especially important when determining the repaired shock absorber. The unsatisfactory condition of certain parameters may indicate poor repair or improper assembly.

Most characteristic faults

When a car moves, as a result of deformation of suspension springs, transverse vibrations of the body occur, which are extinguished by shock absorbers. Due to the increased requirements for smoothness, shock absorbers have become one of the main elements of the modern suspension.

On cars, hydraulic shock absorbers are most widely used, in which the resistance of a relatively viscous liquid passing through calibrated holes of small diameters and a limited section in the valves is used. The complete oscillation cycle includes two periods:

Compression stroke - when the compressed part approaches the unsprung part;

deflection stroke - when the sprung part moves away from the unsprung part.

Shock absorbers are divided into two groups: two-way shock absorbers and one-way shock absorbers, the latter extinguish fluctuations only during recoil. Two-way shock absorbers provide a smoother car travel, so at present, one-way shock absorbers are practically not used.

During diagnostic and repair work, you have to encounter a number of faults that are most typical for shock absorbers.

Process of removal shock absorber diagnostics

The test bench being developed within the VKR framework diagnoses the vehicle shock absorber with an axle load of up to 1 t. It is assumed to diagnose shock absorbers of all types used on cars and minibuses (spring suspension, spring suspension).

Works are performed in the following sequence. A repaired shock absorber is bolted to the bench eyes. Depending on the type of shock absorber, attachment adapters are installed. Then the electric motor is switched on, and the shock absorber response to loading is removed and fixed by strain gauges located in the upper attachment point. After fixation of shock-absorber operation parameters the attached element is unlocked and conclusion on its technical condition is made.

Organoleptic method

When checking the technical condition of the undercarriage, element-wise check the tightening of bearings, plays of the front suspension and steering. To do this, using a lifting device or jack, the wheel is hung out and a bearing play is detected swinging along the vertical axis. Play value must be close to zero. After determining the play vertically, it is rocked in a horizontal plane until the steering wheel starts rotating. In the rear wheels, the vertical and horizontal play are approximately the same, and changes in their value characterize the degree of wear of the bearings of the axle. If the front wheel does not have a vertical play, it is necessary to give the wheel rotational movement and determine the resistance arising from the rotational movement by the time it stops. In cases of fast wheel stop, the bearing tension should be loosened.

Conclusion

In the diploma project, a car suspension repair area with selected profile equipment was designed, and the main indicators and funds were calculated.

During the project, the objectives and objectives of the project were considered.

For uninterrupted operation of ATP, it is necessary to perform diagnostic and repair maintenance of the car suspension on an ongoing basis. The quality of the work performed depends directly on the qualification of specialists and the state of the equipment.

The use of modern equipment for the maintenance and repair of cars facilitates and accelerates many production processes, but requires service personnel to learn a certain range of knowledge and skills: the construction of the car, the main technological processes of maintenance and repair, the ability to use modern instrumentation, tools and devices, as well as constantly improve their skills.

Well-organized maintenance, timely elimination of malfunctions in units and systems of the car, with highly qualified performance of work, allow to increase the durability of cars, reduce their downtime, increase the duration of inter-repair runs, which ultimately significantly reduces unproductive costs and increases the profitability of motor vehicles.

In the process of maintenance and repair of cars, one of the main production divisions that affect the technical readiness, reliability and efficiency of the rolling stock is the car suspension repair section.

In this diploma project, the technical justification of the project is given in the first section: the norms of overhaul mileage, the average values ​ ​ of overhaul mileage, the labor intensity for conducting TO-1 amounted to 10%, TO-2 amounted to 15% and current repairs, car downtime during maintenance and maintenance, annual mileage and number of maintenance per year. The annual mileage of all cars for the year amounted to 2296650 thousand km. The second section defines the minimum number of workers in the department. The area of ​ ​ the compartment is 135m2. The labor intensity of work at the post was at TO1 = 2.2 person/h, TO2 = 8.3 person/h. This scope requires one Auto Locksmith. Equipment for the site was also selected and a detailed description was given. Measures on health, safety and fire safety during electrical work are also considered .

In the economic part of the diploma project, the costs of materials and components, salary costs, expenses and the cost of repair work were calculated. The cost of repair work for 1000 km of mileage is 1907 rubles. The average monthly salary is 66262.5 thousand rubles per month.

Thus, I consider the goals and objectives of the diploma project fulfilled.