Ship propulsion and their design.Devices designed to create persistent pressure are perceived by the vessel, and are the root of the movement, are called propellers. There are propulsors of the evil species: lobed wheels, wing propellers, rpc6 screws, d. The propeller is a disk equipped with three or four vertical swivel blades located horizontally under the stern of the ship to the vertical. shaft, the disc is driven by the electric motor through a bevel gear. The use of winged propellers ensures high maneuverability of the vessel, in the absence of the steering device 11, it is possible to implement the rear odds without reverse engines. In recent years, vane drivers, such as Font Schneider, are supplied with self-propelled cranes, some small vessels and thrusters of larger ships. The propeller has become the most widely used propeller for vessels. The main parts of the propeller are: a hub 1 of a screw with a tapered hole inside the blade 2, the number of which can be from two to six. The blades form a screw surface with which the required thrust force S, Kr, 11a of the shaft is created when the screw rotates. The main geometric parameters of the screw are its diameter D, m, measured between the outer outer points of the blades, and the step t m is the distance between the same blade edges , measured along the axis of the screw.
These parameters are determined by a special calculation, with the diameter of the screw or pain ! (the screw must not protrude from the water) and the speed of rotation permissible for it, at which the phenomenon of cavitation can not occur – the formation of a layer of air bubbles between the blades is covered with water (when the propeller with cavitation the engine can go to ” spacing “, and the screw quickly fails). Cast iron, marbling and phosphor bronze, carbon casting steel are used for the manufacture of rpm screws, and plastics are used for small screw sizes in the last time. 10 design execution The rpm screws are for the purpose of noughts, removable 11 swivel blades
The t1 blades (see Figure 183) are mainly used on ships of the merchant marine fleet. These screws are lined with a small mass and hub dimensions, as well as higher strength under normal operating conditions. Screws with detachable blades are mounted on the service ships to replace the damaged fleet,the conditions of the dome blades are more convenient than those of the whole screw. In addition, the screws are used when the diameter of the screw is large and its repulsion is difficult with the turning blades, otherwise called the vent screws The steps of the step (SRS) are different from the usual ones in that the 11x of the blade is fixed in the hub of the screw “can be rotated about its axis by a specific angle using a special drive.This drive or step change mechanism (MIC) is usually located inside the hub of the screw, therefore, the hub is much larger than that of conventional screws.The mechanism for changing the step is manual, mechanical, mechanical, hydraulic and electric. The composition of the MISH, with the exception of manual, includes: a mechanism for turning the blade, usually placed at the base of the screw; a servomotor creating the forces to rotate the mouths and the brine araes1 th in the section between the propeller shaft and the main motor is the feedback, or device, displays. The figure for the new pitch of the propeller
The n080 rotation mechanism of the blades can be of two types: a serrated crank, the latter being more reliably used in all stressed screw designs (larger washing capacities and diameters, high-speed SLVs of small diameters, etc.). The most common at present is the hydraulic MISH , usually located in the line. To rotate the propeller blades, the energy of the fluid (most often oils with low viscosity) is used under pressure. The hydraulic drive of the MISH is distinguished by the relative simplicity of the device and the ability to create significant working forces with a relatively small diate and mass of the installation. In the foot! te 4 4 screws 11 there is a leash rod 5, padded inside the hollow rpe6nogo shaft 6. By the reason / in the groove to Then the gate of the latter has fallen around its axis, to facilitate rotation of the eu 2 on the lobe of the blade, the blade of the blade is placed in the hub’s pedal on two-rowed horses. comic roller bearings H. At the other end, the piston of the servomotor 7 is connected, connected by a feedback 8 to the movable clutch 12 and the piston of the distributor gold 11. The oil in the distributor slide 11 and the servomotor 7 are fed through the tubes 10 from the oil pump. Controlling the pitch of the propeller blades is carried out by a lever 9, the lower end of which slides into the groove of the movable coupling Guide. The iiril 5 throttle MISH allows you to control the pitch of the propeller from the navigation bridge using a remote nneBa. system.