Ripper - Construction and Road Machines - Course

Contents

Introduction

1. Task

2. Characteristics of the base machine

3. Soil characteristics (IV -VI category)

4. Analysis of suspended ripper structures

4.1 Technical Analysis

5.Tax calculation of ripper

5.1 Determination of forces acting on the machine during tillage

5.2 Calculation of engine power

5.3 Conditions of movement of the base machine with a ripper

6. Calculation of ripper parameters

7. Selecting Operating Positions and Determining Ripper Loads

8. Calculation of ripper hydraulic drive

9. Calculation of ripper tooth post for strength

10. Calculation of ripper stability

Conclusion

Literature

Introduction

Forests occupy a significant part of the area of ​ ​ our country (eastern part), and therefore the logging and timber processing industry in the Russian economy occupies one of the leading places.

In the logging industry, forest roads should ensure year-round forest removal and create normal conditions for forest management.

Therefore, to meet the needs of the forest industry, it is necessary to build about 7 thousand km of permanent forest roads and about 40 thousand km of temporary roads annually.

During the construction of forest roads, the average amount of excavation for 1 km of track is 30005000 m3 in flat terrain, in hilly and low-mountain 40008000 m3.

An effective solution to this problem is possible only if all road construction works are fully mechanized using modern machines and advanced technologies.

Preparatory work during the construction of roads includes the following types of technological operations: clearing of the diversion strip from the forest and shrubs, stumps, harvesting of boulders and large stones, filling of pits and planning, removal of the vegetation layer, loosening of dense soils, installation of drainage channels, etc. On main timber roads, the width of the diversion lane should be at least 30 m. Logging machines and equipment are used for logging and harvesting. To carry out other preparatory work, the industry produces special mounted and trailed machines: cutters, roosters, rippers, stone harvesting machines, ditches, planners.

Rippers are designed for the development of dense and frozen soils, root destruction, for breaking old road surfaces during road repair. Rippers are also used in the development of stone quarries and in the mining industry. Rippers are usually used complete with bulldozers, staplers, excavators. The use of rippers in the development of heavy soils (3-6 categories) increases the productivity of machines working with them by 4-6 times.

Two types of rippers are used: hinged and trailed.

Depending on the purpose of the ripper and the type of work performed, the number of teeth installed on the ripper can be from one to five. For example, for loosening frozen soils, it is recommended to use single-tooth looseners. Therefore, the teeth of the hinged rippers must be removable in order to be able to adjust their number depending on the operating conditions. The ripper tooth struts are straight, curved and with little bending, and are typically provided with detachable tips made of 1215% manganese steel. Tooth tips have a sharpening angle of 2030 degrees. Typically, the posts have a rectangular cross section with a thickness of 60100 mm. The length of the struts is 100300 mm more than the maximum tillage depth hmax to allow the lower beam of the tiller frame to pass over the loose ground. To change the tillage depth hp, the mounting design of the posts allows you to change their position in height.

4.1 Technical analysis.

Structure of ripper tooth strut.

The study of VNIIstodormash cutting of strong and frozen soils (19721974g) showed the inefficiency of complex loosener tooth structures: the inclusion of hard-alloy inserts in the tooth structure (VK8, VK10) increases the tooth life by 46%, and increases the cost of manufacture by 80%, moreover, if the technology for fixing inserts (poor-quality soldering), the destruction of the first 10 hours of the tooth occurred during 5.

nitriding the cutting part of the tooth in order to increase hardness slightly increases the tooth life by 23%. the use of 2-3 teeth on one strut led to a sharp increase in loads on the base machine (increased engine and transmission wear) with a slight increase in productivity up to 5%.

The use of dumps in the design of the tooth does not lead to an increase in the productivity of the ripper in solid and frozen soils.

Therefore, an equal strength stand with one tooth of 40XH2MA steel with a sharpening angle of up to 20 ° was used.

Design of hinged ripper.

A four-point (parallelogram) design was chosen with the attachment of the inner frame to the body of the rear axle of the base tractor, which allows you to use only 1 hydraulic cylinder to drive the tooth of the ripper.

The use of upper and lower rods from channel No. 18 allows you to create a strong and rigid fixation of equipment on the base machine .

Large diameter pipes result in additional material consumption. The use of a box structure (in the form of 2 channels or I-beams) is necessary only for basic machines of very high power (Komatsu: D155A1, D355A-3, D455A1).

The use of 4 ribs of the ripper body with a recess for the angles and channel makes it possible to strengthen their fastening to each other and create a strong structure with increased rigidity, which reduces the load on the units for attaching the ripper to the base machine.

The inclusion of stiffening ribs between the channels additionally increases the rigidity of the structure and creates places for the use of additional teeth for loosening softer soils.

Welded structures of the main ripper units emphasize the uniqueness of development, since cast or stamped structures are used in serial samples.

5. Traction calculation of the ripper.

Traction calculation of road construction machines, including gels, includes three stages:

determination of individual resistances W1wn acting on the machine ;

determination of total resistance force ΑWi;

determining the required engine power of the base machine Npotr ;

Define motion conditions when operating under specified conditions.

Conclusion.

During the course project, the following sections of the calculation and explanatory note were developed:

technical characteristics of tractor T130GP,

characteristics of soils with I -VI category,

analysis of design of suspended rippers,

traction calculation of the ripper is performed,

determined the forces acting on the base machine,

calculated the conditions of movement of the ripper,

parameters of the ripper are selected,

defined the operating (including critical) positions of the base machine and calculated loads,

main parameters of hydraulic drive are calculated,

designed for the strength of the tooth strut,

stability of the ripper was checked.

In the graphic part of the course design, a scheme for placing the suspension ripper on the base machine, an assembly drawing of the ripper, and detailed drawings of the main parts were developed.

These works made it possible to consolidate theoretical knowledge on the course "construction and road."