Designing a universal single-bucket excavator

Contents

Introduction

1. Size of excavator base part

2. Bucket Options

3. Linear dimensions of boom and handle. Working dimensions

4. Operating equipment drive parameters. Select hydraulic cylinder types and associate them

4.1 Selection of ladle hydraulic cylinder

4.2 Selection of handle hydraulic cylinder

4.3 Selection of boom hydraulic cylinder

5. Parameters of pump-power plant. Selection of pump and prime mover sizes

6. Parameters of rotary platform drive and selection of hydraulic motor size

7. Drive parameters of running devices. Selection of hydraulic motors sizes

8. Excavator performance

Conclusion

Bibliographic list

Introduction

Currently, the park of construction single-bucket excavators in our country and abroad is dominated by hydraulic machines with rigid suspension of working equipment. The exception is excavators with working dragline equipment, in which a flexible (rope) suspension is preserved. The widespread use of hydraulic excavators is due to the undeniable advantages of a hydraulic volume drive before a drive with a mechanical transmission and flexible suspension of working equipment, first of all, the simplicity of kinematic links between energy sources and consumers, the ability, by simple means, to convert the rotational motion of the prime mover into the translational motion of the final actuator link; the ability to realize large forces on working bodies with minimum sizes of transfer devices, possibility of force action on working elements in both direct and return directions, etc. These advantages provided hydraulic excavators with high efficiency, in particular, lower material capacity than rope excavators.

Further improvement of hydraulic excavator structures is connected with optimization of their main parameters, the first stage of which is mastering the methods of calculating their main parameters. To date, these methods have not yet been formed into a single theory, primarily due to the variety of approaches in the design of excavators by various factories, research institutes and foreign companies, in connection with which, for educational purposes, mathematical modeling of the functioning processes of hydraulic reverse shovels as the main type of working equipment of these machines is adopted as the main method. In some cases, with insufficient volumes of raw materials for mathematical modeling, analogies are used from the experience of designing models of excavators similar to the device with their correction at subsequent stages of calculation. The training manual defines the procedure for calculating the main parameters of hydraulic excavators with working equipment reverse shovel, including assignment of geometrical dimensions of the excavator base part and its working equipment, selection of hydraulic cylinders for bucket, handle and boom turning, their binding to working equipment, assignment of geometric dimensions of bucket turning mechanism, selection of hydraulic motors for drive of rotary platform and running device, selection of internal combustion engine pumps, determination of gear ratios of transmission mechanisms, determination of output characteristics, including: parameters of the working zone, speeds of working movements, speeds of movement of the excavator and theoretical productivity.

Conclusion

During the course project, a single bucket excavator with a reverse shovel was designed.

Based on literature and patent sources, the TVEX ET18 excavator produced by Tverskaya Excavator OJSC by the Tversky Excavator Plant was chosen as a prototype. The excavator is designed for the development of pits, trenches, quarries in soils of the Ⅰ‒ⅠⅤ category, loading and unloading of bulk materials, loosening of rocks and frozen soils (with a size of pieces of not more than 200 mm), as well as for other work in conditions of industrial, urban, rural, transport and reclamation construction. The turntable is unified with the EC18 excavator. The excavator remains operable in the ambient temperature range from

- 40˚ to +40˚S. Hydraulic system is made using imported components: hydraulic distributor, filtration elements, cooling unit and hydraulic cylinders. A significant difference between the modernized machine and the base model is the BoschRexroth hydraulic system, a more powerful engine. The presence of a powerful engine allows you to increase the performance and efficiency of the digging mechanism. A new soot system is installed on the excavator, which allows improving the functionality of the machine, its appearance, and most importantly, making it more convenient to maintain.

The main calculations were also made:

- calculation of maximum digging force,

- performance calculation,

- calculation of traction force.

Drawings of the general view of the base machine, cross sections of the HF attachment joints and a drawing of the widened ladle with details of the tooth attachment to it have been developed.