Electric booster of a car - exchange rate

Contents

Structure

Cover Sheet

Thesis Project Assignment

Paper

Table of contents

Introduction

1 Analysis of economic activity of Belebeyevskoye ATP OJSC

  1.2 Human Resources Analysis and Use

  1.3 Analysis of profitability indicators

2 Development of electric amplifier

  2.1 Analysis of existing structures

  2.2 Description of development

  2.3 Calculation of units

3 Calculation of steering elements

4 Process part (installation and maintenance of rudder electric booster)

5 Project safety and environmental friendliness

  5.1 Ensuring labor safety conditions in OJSC Belebeyevskoye ATP

  5.2 Safety features during operation of  tractor T-30-69 with electric booster embedded in steering column 

  5.3 Environmental protection measures

 5.4 Measures to protect the population and values

in emergency situations

6 Economic part

Conclusion

List  of literature

Applications

Graphic part

1 Business Analysis

2 Analysis of existing structures

3 Functional diagram (for development)

4 Assembly drawing

5 Detail

6 Installation drawing

7 R&D (ergonomic calculation)

8 Job Instruction (Electric Booster Unit)

9 Economic part

1 ANALYSIS OF ECONOMIC ACTIVITY OF Belebeyevskoye ATP OJSC

1.1 Location and short description of the farm

Belebeyevskoye ATP is located in Belebey, 190 km from the republican center. The company begins its history in 1939 when the transport artel was formed, in 1950 the company became part of the Bashavtotrans association. In 1972, the Belebeyevskoye ATP merged with the Priyutovskaya transport column and continued its activities under the new name Belebeyevskaya transport column No. 1834.

This company specializes in performing the following types of work and services: servicing industrial and road construction, transporting people along urban, suburban, intercity and inter-regional routes. 

The service area of ​ ​ the enterprise covers the nearby areas of Ermekeevsky, Bizhbulyaksky, Belebeevsky, and inter-regional flights are carried out. The cargo park of the Belebeyevsky ATP also expands the boundaries of its activities and, in addition to transportation within the borders of the republic, delivers cargo to Moscow and the Moscow region., Novosibirsk, Chelyabinsk and the Tyumen region.

The main competitors in the performance of works and services in this area are Tuymazinsky ATP (Tuymazy) and Oktyabrskoye ATP (Oktyabrsky). 

The location of the enterprise is favorable for the provision of the market for road services (30 km from the Moscow-Chelyabinsk highway  ).

In the organizational management system of a motor transport enterprise, three independent control units can be distinguished: operational, technical and economic, each of which is subordinate to the corresponding head

The financial and production activities of the enterprise are carried out on the basis of current and promising plans, independently developed and approved by the management of the Belebeyevsky ATP. The profit remaining in the enterprise after paying taxes and other payments to the budget comes to the full disposal and use of the enterprise on its own.

 Human Resources Analysis and Utilization

The revenue from the work performed, the average number of employees and their average annual salary are accepted from the annual accounting report.

The data show that the absolute lag behind the increase in wages compared with the increase in productivity during the period under review is 130.8 per cent. This suggests that increasing labor productivity with a slight increase in wages leads to an increase in profits and a decrease in wage costs for work. As a result, the financial situation of the enterprise is improving.

 1.3 Analysis of profitability indicators

The main financial and economic indicators of the enterprise for three years are given in tables 1.3, 1.4.

The values ​ ​ of revenue, the average number of employees and the average annual value of fixed assets and working capital are taken from the annual accounting report of the enterprise for 2006, 2007 and 2008 .

Development of electric amplifier

2.1 Analysis of existing steering gear structures 

     

 Mechanically driven steering (Figure 2.1) is a helical pair located at the bottom of the steering column. Shaped nut articulated with paired lever is screwed onto end of steering shaft with trapezoidal thread. The lever is installed on the nozzle shaft, on the splined end of which the nozzle and the longitudinal link of the steering drive are sequentially fixed. Rotation of the steering wheel through the splined joint is transmitted to the shaft and nut, due to which rotation of the paired lever and nozzle is ensured. In the upper part of the steering shaft there is a conical driving gear, which is in constant engagement with the gear of the steering wheel reverse. With reverse control, the steering wheel is equipped on the gear shaft.

Steering with hydraulic booster (Figure 2.2) is made in one unit with control mechanism. In addition to the hydraulic booster, the control includes a steering drive, as well as a steering mechanism drive connecting the steering wheel with the hydraulic booster. Steering gear drive consists of two tubular shafts interconnected by articulated coupling. Front shaft has splined bushing fitted on outer end of worm of steering mechanism. The rear shaft, on which the steering wheel is equipped, is mounted in a special post on two bushings. Steering shaft post is secured on hydraulic system control levers bracket. 

The steering mechanism (two-start worm and oblique sector) is installed on the body. Inner space of housing is used as oil tank of hydraulic booster. The power cylinder is attached to the hydraulic booster with covers and four bolts. Cylinder piston is sealed with rubber and two leather rings. Sector is engaged simultaneously with worm and rod rack. The engagement of the worm - sector is controlled by turning the eccentric adjustment cover of the bushing, the engagement of the rack - sector - by changing the number of gaskets under the stop flange. Sector and nozzle are fitted on rotary shaft on conical rectangular splines. Distributor slide valve is mounted on worm shank. Distributor housing is bolted to amplifier housing. 

Centering springs keep slide valve in neutral position. Sliders, which are affected by springs, on one side rest against amplifier housing, on the other - against distributor cover and partially against thrust washers. Valve cover accommodates safety valve limiting oil pressure within the range of 7580 kgf/cm 2. Safety valve consists of ball, seat, spring, two aluminium gaskets and adjusting plug. 

Features of steering operation with hydraulic booster include the possibility of providing them with both mechanical and hydraulic connection between steering and guide wheels. Rotation of guide wheels at low rotation resistances occurs without actuation of hydraulic booster, because axial force on worm is not sufficient for compression of centering springs and movement of slide valve. In this case, the worm rotates the toothed sector and the rotary shaft, then the force is transmitted to the steering trapezoid and guide wheels through the bevel.

If at high rotation resistances the axial force on the worm exceeds the force of pre-compression of springs centering the distributor spool, the hydraulic system begins to operate. Axial shift causes movement of the slide valve, providing oil supply to the corresponding cylinder cavity. When steering the steering wheel, the worm is screwed onto the sector or screwed from it until the washers abut the body and moves the slide valve, which opens the channels of the distributor. Oil supplied by pump is supplied under pressure to one of chambers of power cylinder and moves piston and rod. The rod, acting through the rack on the sector, turns the shaft and the bevel in one or the other direction depending on the direction of rotation of the steering wheel. At pressure above 7580 kgf/cm                               2

oil presses out the ball safety valve and, bypassing the distributor, enters the drain cavity of the hydraulic booster.

Two-circuit hydraulic steering schemes (Figure 2.3) are used for traction-class wheeled tractors 3.0 and higher. In them oil is supplied from hydraulic pump to actuating hydraulic cylinder via two hydraulic circuits. 

The flow amplifier controls the oil flow from the pump to the hydraulic cylinder in accordance with the direction and magnitude of the control flow set by the dosing pump. Flow amplifier consists of distributing spool, pressure regulator, small and large throttles, flow regulator and check valve. The order of operation of the system under consideration when turning the tractor is as follows. When steering the steering wheel, the spool of the dispenser pump moves from the neutral position to the side depending on the direction through the dispenser (motor-pump) under the corresponding end of the spool and moves it to the opposite extreme position. In this case, pressure is also created under the end of the pressure regulator. Oil is supplied from dosing pump through small throttle and slide valve to corresponding cavity of power hydraulic cylinder. At the same time oil gets into hydraulic cylinder through check valve, pressure regulator, large throttle and slide valve. Since the pressure regulator balances the pressure before the throttles, the oil flow rate will be proportional to the areas of their flow sections. By varying the flow area of the throttle, the oil flow rate can be varied within wide limits.

When oil supply from the dosing pump is stopped, the flow booster spool under the action of springs returns to neutral position and closes the hydraulic cylinder cavities. The hydraulic pump is unloaded to drain oil into the tank through the flow regulator and the dosing pump.

In case of non-operating hydraulic pump the dispenser operates from the steering wheel, and oil is sucked through two check valves. At the same time, the force on the steering wheel does not significantly increase, but the number of turns of the steering wheel to perform the rotation of the tractor significantly increases     .

Electric power steering (EUR) is an electromechanical system of a car designed to reduce the control force applied to the steering wheel. In the design of a modern car, the electric steering amplifier gradually replaces the steering hydraulic amplifier.

The main advantages of the electric power steering in comparison with the hydraulic power steering are: 

- easy control of steering characteristics; 

- high information value of steering; 

- high reliability due to lack of hydraulic system; 

- fuel economy due to energy saving. 

The most advanced in terms of design is electromechanical steering power. Known designs of such an amplifier are:

- electromechanical power steering with two gears (Figure 2.4);

- electromechanical power steering with parallel drive (Figure 2.5).

Electromechanical steering power has the following device: 

- amplifier motor; 

- mechanical  transmission;

- control system. 

Electric power steering is combined with steering gear in one unit. In the design of the amplifier, an asynchronous motor is usually installed. 

The mechanical transmission provides torque transmission from the electric motor to the steering rack. In an electric booster with two gears, one gear transmits torque to the steering rack from the steering wheel, the other from the amplifier motor. For this purpose, two sections of teeth are provided on the rack, one of which serves as an amplifier drive. 

In an electric booster with a parallel drive, the force from the electric motor is transmitted to the steering rack using a belt gear and a special ball screw mechanism. 

Control system of rudder electric booster includes the following elements :

- input sensors; 

- electronic control unit; 

- actuator. 

Input sensors include steering wheel angle sensor and steering wheel torque sensor. The steering power control system also uses information from the ABS control unit (vehicle speed sensor) and the engine control unit (engine crankshaft frequency sensor). 

Electronic control unit processes sensor signals. In accordance with the program, a corresponding control action is generated on the amplifier motor actuator. 

The electric power steering provides the operation of the steering control of the car in the following modes: 

- turning of the car; 

- turning the car at low speed; 

- turning the car at high speed; 

- active return of wheels to middle position; 

- maintaining the middle position of the wheels .

Turning the car is carried out by turning the steering wheel. Torque from the steering wheel is transmitted through the torsion bar to the steering mechanism. Torsion bar twist is measured by torque sensor, steering wheel turn angle is measured by steering wheel turn angle sensor. Information from the sensors, as well as information about the speed of the car, the speed of the crankshaft of the engine, are transmitted to the electronic control unit. The control unit calculates the required torque value of the amplifier motor and provides it to the motor by changing the current value. Torque from the electric motor is transmitted to the steering rack and further, through the steering rods, to the driving wheels .

Thus, the turning of the wheels of the car is carried out by combining the forces transmitted from the steering wheel and the amplifier motor. 

Turning the car at low speed is usually carried out during parking. It is characterized by large angles of rotation of the steering wheel. The electronic control system in this case provides the maximum torque of the motor (the so-called "light steering wheel"). 

When turning at high speed, opposite the electronic control system provides the lowest torque (the so-called "heavy steering wheel"). 

The control system can increase the reactive force generated by turning the wheels. The so-called active return of the wheels to the middle position occurs .

During the operation of the car, there is often a need to maintain the average position of the wheels (movement in lateral wind, different tyre pressures). In this case, the control system corrects the average position of the steered wheels.

2.2 Description of development

The electromechanical steering amplifier (EMUR) is an electronically controlled reduction-free electromechanical system designed to reduce the force applied to the steering wheel by the driver and increase the speed of the command to change the direction of movement.           

Electric steering booster built into tractor steering column comprises housing, torque pickup made up of torsion bar and torsion bar twist angle meter, steering shaft consisting of input shaft and output shaft, compensating moment electromechanism made up of electric motor with hollow rotor coupled with output shaft and mounted on two bearings. Output shaft is embraced by hollow rotor installed on it. Body consists of two volumes with different radial dimensions relative to steering shaft axis. In the first volume, which is an electric motor body, there is a partially input shaft with a hollow section, a torsion bar and a partially output shaft with a hollow section, on which a rotor enclosing it is fixed, and in the second volume - a torsion angle meter and, partially, input and output shafts. The first volume contains two end faces on top, usually containing longitudinal cylindrical sections, with bases in the form of a segment of a circle.

The output shaft part located outside the first body volume contains an end splined part on which the intermediate shaft fork is attached. Parts of input shaft and output shaft located inside the first volume have splined parts freely entering each other for movable connection to each other at low torque loads on steering shaft, and at high loads splines of parts rest against each other, determining maximum torsion angle. Torsion bar is arranged in hollow sections of inlet and outlet shafts.

The torsion bar twist angle meter contains a fixed element - a body and two movable elements. Meter is installed and fixed in slots of second volume by protrusions on housing. Movable element is connected with splined part of input shaft, and movable element - with end face of output shaft.

The surface of the end wall of the first volume is spaced from the end of the output shaft by a distance equal to at least double the length of the end spline part of the shaft. An electric booster support is attached to the end wall, and an inlet shaft casing with an upper support is attached to the end wall of the second volume.

The input shaft is installed on two bearings and in the end wall of the second volume and in the casing.

The wheels are turned by turning the steering wheel. Torque from the steering wheel is transmitted through the torsion bar to the steering mechanism. Torsion bar twist is measured by torque sensor, steering wheel turn angle is measured by steering wheel turn angle sensor. Information from sensors is transmitted to electronic control unit. The control unit calculates the required torque value of the amplifier motor and provides it to the motor by changing the current value. Torque from the electric motor is transmitted to the steering mechanism and further, through the steering rods, to the driving wheels.

The proposed electromechanical steering power works as follows. When the driver turns the steering wheel, a moment occurs on the input shaft, a mismatch occurs between the input and output shafts. Torsion bar arranged between them twists by angle proportional to torque value. The magnitude of this angle is determined by the torque sensor. This angle is a task for the engine control system. When the torque on the input shaft exceeds the specified minimum torque, the electric motor control unit generates a power control signal applied to the windings of the electric motor to create the required compensating torque on the steering mechanism. Value of signal on winding is formed taking into account signals of rotor position sensor and moment sensor on steering wheel. Control unit receives signals from speed sensor and crankshaft rpm sensor. As the speed increases, the compensating moment drops. 

Thus, the rotation of the tractor wheels is effected by combining the forces transmitted from the steering wheel and the amplifier motor.

Main technical characteristics of the electric amplifier:

- supply voltages (nominal) - 12 V;

- maximum compensating moment - 35 Nm;

- maximum consumption current - 50 A;

- consumption current (force on steering wheel is applied, output shaft of amplifier is blocked) - not more than 15 A;

- weight of electric booster together with steering column - 12 kg.

Development of electrohydraulic nozzle inspection technology

  A routing is the only working document that reflects all issues related to the manufacture of parts or the assembly of products       . It is the organizing beginning of the technological process of product production. This is a complete source of information for the worker and the wizard about the sequence of work in the workplaces; about equipment, accessories and tools, materials and power sources, requirements to the product before and after the performed operation. The routing defines not only the operations or techniques associated with qualitative changes in materials, workpieces, but also the rules for their movement, storage, control and testing methods, special safety and industrial sanitation rules that must be observed during the execution of the operation. It contains the level of work and information related to the standardization of labor costs.    

  In accordance with the topic of the diploma project, it is necessary to develop a technology for checking electrically controlled nozzles using the presented bench. The process is presented as follows:

4.1 Install the nozzle on the bench using the key S14, the labour intensity of this operation is 0.03 people.

4.2 Connect sensors, fuel lines to the installed nozzle, attach the nozzle on the sleeve, using the switches S13 S17, the labor intensity of this operation is 0.05 people.

4.3 Check injector (bench actuation):

    4.3.1 Check the injector in the start-up mode, using the measuring system and personal computer, the labor intensity of this operation is 0.05 hourly;  

    4.3.2 Check the injector in idling mode, using the measuring system and personal computer, the labor intensity of this operation is 0.025 people.

    4.3.3 Check the injector at nominal operation mode, using the measuring system and personal computer, the labour intensity of this operation is 0.016 people.

    4.3.4 Check the injector in the maximum load mode, using the measuring system and personal computer, the labor intensity of this operation is 0.016 people.

    4.3.5 Check the injector for tightness, using the measuring system and personal computer, the labor intensity of this operation is 0.008 people.

4.4 Analyze the obtained parameters and detect the state of the nozzle, the labor intensity of this operation is 0.016 people;

4.5 Disconnect sensors, fuel lines, sleeve using switches S13 S17, labour intensity of this operation is 0.05 people.

4.6 Remove the nozzle from the bench using the key S14, the labour intensity of this operation is 0.03 people.

The stand is serviced by one person, the total difficulty of checking one nozzle is 0.291 people.