Modernization of bulldozer t 180

Contents

Contents

Introduction

1. General part

1.1 Overview of soil development methods

1.2 Review and analysis of foreign and domestic machines and structures

1.2.1 Bulldozers of domestic production

1.2.2 Bulldozers of foreign producers

1.2.3 Analysis of rippers

1.2.4 Analysis of bulldozers from the ripper

1.2.5 Setting the Course Design Issue

1.2.6 Purpose, scope and technical characteristics of the machine

1.2.7 Overview of existing ripper design

2. Special part

2.1 Selection of the main parameters of the ripper

2.2 Traction calculation of ripper

2.3 Calculation of the drive power of the base machine

2.4 Checking the ripper for stability

2.5 Calculation of ripper capacity

3. Strength calculations

3.1 Tiller Strength Calculation

3.2 Strength calculation of the joint element

3.3 Tooth Strength Calculation

Conclusion

List of literature used

Introduction

The most common and labor-intensive type of construction work is earthen. Earthworks mechanization plays a primary role in increasing labor productivity, improving working conditions and reducing the cost of work performed.

In the total volume of construction work, earthworks occupy a significant specific gravity. About 20% of the total amount of earthworks carried out per year falls on the development of frozen soils, the cost of these works is the same as the rest of the amount of earthworks carried out on non-frozen soils. Frozen soils include soils that contain ice at a negative temperature and therefore change their structure, that is, they lose viscosity, looseness, and other properties inherent in these soils before freezing. Soil development technology is largely determined by climatic conditions. Two different methods of soil development are used: in a non-frozen state; in a frozen state.

To create highly efficient machines that develop soil in non-frozen and frozen states, one of the most important issues is the method of calculating the resistances that can arise on working equipment during soil development.

In accordance with the general methodology of knowledge, in order to solve this issue, it is necessary to comprehensively use experimental and analytical studies of the processes of interaction of working bodies of earth-moving machines with soils of any state. It is necessary to comprehensively use such areas of science as the development of physical and analytical foundations of the theory of soil destruction in various mechanical ways.

Earthworks are widely used in industrial and civil construction, in agriculture and mining, as well as in the extraction of raw materials for the construction materials industry. By purpose, they are divided into earth-moving (excavators, bulldozers, staplers, graders, graders - elevators, rippers), transporting (cars - dump trucks, land carts, conveyors, ground throwers) and soil-compacting (rollers, ramming, vibration and other machines). Earth-moving machines develop loose and coherent soils, as well as loose and immerse frozen and rock soils.

The engineering and technical personnel are faced with urgent tasks related to the improvement and development of machines and working equipment, the use of scientifically sound progressive construction technologies, improving maintenance and improving the efficiency of operation of equipment in winter conditions.

General part

1.2.4. Analysis of bulldozers with rippers.

Every serious manufacturer, trying to make its products more attractive, constantly improves the design of machines, improving technical characteristics and design, expanding the nomenclature and comfort of the operator. Of course, the main direction of development of bulldozers with rippers is to increase its productivity and efficiency:

- increase of speed of working operations and loosening forces, which ensures increase of cycle efficiency;

- improvement of geometry and kinematics of the boom and handle, which increases the work area;

- automatic programming of engine operation modes;

- use of fast-acting grips for mounted equipment;

- reduction of frequency and scope of technical services;

- improvement of cross-country ability and safety during transport movement and in operating modes;

In modern bulldozers with rippers, great attention is also paid to the working conditions of the operator. The machine cannot be presented without protection of the cockpit by ROPS system structures - from damage during overturning and FOPS - from objects falling from above. Sound -, vibration and heat insulation of the cab, ventilation, air conditioning and heating (climate control machine), ergonomics of the operator's workplace are mandatory.

But the most important thing in a modern bulldozer with a ripper, like a hundred years ago - reliability, durability and convenience of maintenance.

The energy and metal capacity of bulldozers with a ripper directly depends on:

-gabarites of the machine, from which it is important whether the bulldozer will be maneuverable and whether it will be able to carry out ripping operations in inaccessible places;

- equipment of the machine with a control panel (mainly in Russian) with modes of adjusting the hydraulic system for a specific type of operation, and the bulldozer automation itself selects the mode of operation. A number of models have electronic systems for recording major systems;

- high productivity and operability are ensured thanks to the electronic control system EPOS of the South Korean company DAEWOO;

- equipment of machines with on-board computers, which record operation of machine systems and simplify diagnostics of malfunctions; these systems automatically select modes of operation and quick transfer of engine from full load to idle mode and back.

From the above it follows that the more equipped the machine with automation, the less energy and metal capacity it decreases; since automated control reduces the number of various nodes, levers and rods in the control of the bulldozer, which affects metal capacity. Also, with this control, energy consumption is reduced, which affects the energy capacity of the bulldozer .

Nowadays, the replacement of individual units and parts of machines made of steels with lighter metal alloys, as well as various polymeric substances (plastics) is widely developed.

The improvement of the undercarriage of bulldozers does not stand still.

The main frame of the rotating part of the EX5500 bulldozer has a box-like structure. The loads acting on the support-rotary device are leveled, due to which it was possible to increase the service life.

On domestic bulldozers, new progressive power supply systems were used with the introduction of automatic control of the engine depending on its load, with combined control of hydraulic pumps for energy recovery during idle movements, optimization of modes and cycles of operation, etc., these systems provide fuel savings of up to 20% and increase in labor productivity, as well as significantly facilitate the work of the driver. From all this follows a decrease in the energy and metal capacity of bulldozers.

Currently, when developing frozen soils and other soils, the question arises of creating an efficient and productive machine that works reliably in any conditions, therefore, work aimed at designing hinged equipment based on a mass industrial bulldozer with a ripper is relevant.

1.2.5 Setting of course design issue.

The purpose of this course work is to improve the ripping equipment based on the T180KS tractor. The creation of basic machines of high unit power makes it possible to use rippers in any ground conditions. However, significant dynamic loads arising during cutting and reaching 2... 5 multiples of static values ​ ​ lead to the dissipation of part of the energy in the parts and assemblies of the base machine and loosening equipment, which causes not only premature failure of parts and assemblies, but also a decrease in loosening efficiency.

The ripper member is a tooth or a plurality of teeth arranged adjacent or in ledges. Teeth when moving destroy the ground not only in front of themselves, but also on the sides. Optimal values of tooth geometrical parameters depend on physical and mechanical properties of destroyed soil. The number of teeth is taken from one to five depending on the purpose of the ripper of the required grip width, loosening depth, tractor power and physical and mechanical properties of the soil.

The efficiency of loosening largely depends on the shape and size of the tip. For weak highly abrasive rocks, longer tips are recommended, short tips for frozen ones. To increase the width of the loosening strip, wideners with a rigid or hinged attachment are used.

Therefore, in this course work, we will change the shape of the tip and plate applicable to our type of soil.

1.2.6 Purpose, scope and technical characteristics of the machine

According to the established concepts, a loosener is an excavating machine consisting of a basic tractor and rear hinged loosening equipment, designed for layer-by-layer loosening of rock and frozen soils, as well as other strong soils, as well as other durable materials in various climatic conditions.

The loosening hinged equipment comprises a hinged device in the form of a system of rods and a working beam, which provide oriented mobility and a fixed position of the working tooth.

Loosener on the basis of tractor 15 of traction class (T180, T-180KS) is widely used for mechanical destruction of soils of category 1-4 on large areas of loosening, during the development of pits, wide trenches, excavations in construction, during overburden work at mining enterprises, as well as in the construction of hydrogenated structures and public roads.

The increasingly effective use of rippers based on the tractor of the 15th traction class in the development of rock and frozen soils is due, on the one hand, to a significant increase in the capacity of the base tractor and, on the other, to the modernization of hinged devices and the design of working bodies.

The use of these rippers in the development of high-strength, frozen and rock soils is more economically feasible than in drilling and blasting operations; this also leads to their widespread use.

Technical characteristics of the ripper

Basic tractor T180KS

Power, kW 132

Traction class 15

Bulldozer equipment DZ-35B

Dimensions of the machine in the transport position:

Length, mm 6840

Width, mm 3640

Height, mm 2825

Machine weight, kg 21580

Ripping equipment:

Four-link view

Number of teeth 1-3

Greatest tillage depth, mm 700

Weight of equipment, kg 2580

Rear angle of entry, 20

Technical and economic indicators

4.1 Description of the initiative node.

In the course project, a change in the geometric parameters of the tip and the front plate of the ripping equipment was chosen as the initiative node. In order to reduce the resistance of the soil to ripper cutting, thereby increase productivity and reduce the energy consumption of the ripper.

Teeth of all types are designed so that, while maintaining the necessary strength, their frontal surface is smaller, for this they are sharpened at an angle of up to 60 ° with a jumper between the walls... 1.5 3.0 cm.

The efficiency of loosening largely depends on the shape and size of the tip. For weak highly abrasive rocks, longer tips are recommended, short tips for frozen ones. To increase the width of the loosening strip, wideners with a rigid or hinged attachment are used.

To manufacture high-strength tips and increase their wear resistance, magnesium-carbon or nickel steels are used. Forged, cast or forged-welded tips are usually made.

The design is characterized by the fact that the tip has a trihedral shape. The side faces are pointed, with an angle of 40... 60 ° at the apex .

The destruction of the ground by such a tip occurs as follows. Under action of traction force of tractor, sharpened edges of triangular projection come into contact with ground first, which create advance deformations and cracks in direction of surface. Further development of deformations and separation of the loosening zone into separate sections occurs under the influence of lateral inclined surfaces of the triangular projection on the soil. The final destruction of the soil, which has already partially lost its initial strength, occurs under the influence of flat sections of the front face.

Thus, the tip destroys the soil separately with three power flows, as a result of which the average maximum loosening force and the dynamic coefficient are reduced.

Further, a frontal plate is buried into the soil, which has side faces beveled to the middle, due to which the resistance of the soil to cutting is reduced. The plate divides the soil into two parts.

Since in case of blunt profile cutting the process of chip formation is connected with periodic formation of individual chip elements, during cutting with sharpened profile the main mass of soil deformed symmetrically by sharpened profile is pressed into side walls of cut slot.

From this it follows that changing the geometric parameters will improve the operation of the ripper not only in terms of productivity and energy intensity, but also provide a smoother movement during loosening without dynamic loads. And it will improve not only the technical and economic performance of the ripper, but also operational.

Conclusion

Modernization of the bulldozer with loosening equipment, by changing the geometric parameters of the tip and the front plate on the loosening equipment, will allow to destroy frozen soil with a more reduced energy capacity. The developed design allows you to effectively develop frozen soils of category IV, allows you to increase the productivity of the ripper due to improved technical, economic and operational performance.