Bulldozer.ppt
- 1. BULLDOZER
- 2. Earth-moving machines (EMM) are self-moving machines on pneumatic or caterpillar tracks, designed for profiling earth embankments, moving and leveling soils, separating rock mass from the massif and transporting it. EMM Bulldozer Motor grader Scraper Grader elevator A characteristic distinguishing feature of these machines is that all elements of the working process are performed during their movement. Earthmoving and milling machines Workflow of EMM Soil digging Transportation Unloading
- 3. A bulldozer is an earth-moving machine consisting of a tractor equipped with a controlled blade with a knife for layer-by-layer cutting, moving the soil over short distances (up to 100 m), leveling and laying it.
- 4. Bulldozer working cycle Bulldozer - cyclic machine 1. gouging (cutting) and soil collection (formation of a drawing/ drag prism); 2. displacement (displacement of the drawing prism); 3. unloading of soil (by lifting the blade); 4. idling (return to the bulldozer face to the place of soil collection). Cycle work steps :
- 5. The largest bulldozer in the world Komatsu D575A
- 6. Function 1. Layer-by-layer cut and move the soil at: - construction of road embankments and excavation; - digging of ditches; - digging of ditches, holes, trenches, pits. 2. Perform the leveling (rough leveling ± 10 cm) of sites, slopes, leveling of the dumped soil. 3. Distribute on the surface of various bulk and lumpy materials (sand, crushed stone, gravel, etc.). 4. Felling of trees, uprooting of stumps, removal of stones, clearing of sites and roads. 5. Pushing scrapers at the final stage of loading the bucket (work as a "pusher").
- 7. Classification By use: a) general purpose; b) special purposes: for underground mining (mines, tunnels), for underwater mining, for work in the holds of ships. By type of running equipment: a) tracked; b) wheeled. Whenever possible to turn the blade: a) with a fixed blade (the blade is permanently installed in the plan at an angle of 90 ° to the longitudinal axis of the machine); b) with a rotary blade or universal (the blade can be installed in the plan at an angle of 90 ° and other angles to the longitudinal axis of the machine). According to nominal tractive effort: - very light ≤ 20kN - light 30 - 50 kN - medium 100 - 150 kN - heavy 200 - 250 kN - extra heavy> 300 kN. а) b)
- 8. GENERAL STRUCTURE (dozer with fixed blade) 1 - right hydraulic cylinder for blade lift; 2 - mechanical brace; 3 - dozer blade; 4 - right push bar; 5- right support of a push bar with a harness hinge.
- 9. Bulldozer with rotary blade 1 - hydraulic cylinder for lifting and lowering the blade; 2 - vertical brace; 3 - blade; 4 - pushing frame; 5 - support hinge; 6 - ball joint; 7 - bracket; 8 - horizontal brace.
- 10. 1 - replaceable blade; 2 — frontal sheet; 3 — top stiffening frame; 4 — brace attachment lug; 5 — lug that connect blade with the lifting-lowering hydraulic cylinder; 6 — push bar attachment lug; 7 — bottom stiffening frame Dozer blade
- 11. Blade types 1. Straight blade 2. Soil drag prism 3. Right and left soil rolls Straight blade with flaps Hemispherical blade (3 parts) Spherical blade (5 pieces) 1 - direct rotary; 2 - straight fixed; 3 - hemispherical; 4 - spherical; 5 - spherical for bulk materials; 6 - with pushing plate
- 12. Determination of bulldozer productivity Operational productivity is calculated by the formula, m3 / h : where V – volume of soil, a bulldozer moved in one cycle, m3; Кп – coefficient of soil loss during movement; Кв – coefficient of bulldozers time use (Кв=0,85…0,90); Тц – cycle time, sec; Кр – soil loosening coefficient.