Elementary Hydraulic Systems

The simplest hydraulic system is perhaps the hydraulic shock absorber which consists of a pump (piston) and resistance. Another elementary type of system is the hydraulic weighing machine, which consists of a non-continuous pump element(piston or diaphragm) and a pressure gauge.

Other elementary systems consists of a jack, transmission line, and a pump of the non-continuous type without control gear, although valves may still be present for secondary purposes. Systems of this type are used for remote transmission of manual or pedal effort or motion, or for remote transmission of instrument indication.

The simplest best known system of this type hydraulic brake

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Основные параметры подшипников:

Максимальные динамическая и статическая нагрузка (радиальная и осевая).

Максимальная скорость (оборотов в минуту для радиальных подшипников).

Посадочные размеры.

Класс точности подшипников.

Требования к смазке.

Ресурс подшипника до появления признаков усталости, в оборотах.

Шумы подшипника

 

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Tubing, Tube Connectors, and Flexible Hose

The various units of a hydraulic system are connected with some form of tubing or flexible hose.

Tubes are joined by means of tube connectors, usually of the same material.

Tubing. Some of the factors governing the selection of tubing are corrosion, temperature weight, mechanical strains, abuse and pressures.

Because of its light weight, aluminum-alloy tubing and fittings are used wherever possible.

Fittings are designed to withstand the bursting pressure that the tube of maximum wall thickness will withstand, assuming that the tube and fittings are of similar materials. For general heighpressure installations steel tubes and fittings are recommended.

Flexible Hose. Flexible hose is used to connect hydraulic units between stationary and moving parts. Hoses are made up of varying layers of synthetic rubber, fabric, and wire braid.

 In installing flexible hose care must be taken that the hose is free from twists. Under pressure a twist will rotate the hose and loosen the connection, causing failure.

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 II. Use little or few.

 1. I have... time, so I can't go with you. 2. He has... English books. 3. There is... ink in my pen. Have you got any ink? 4. There are... bears in the zoo. 5. Tom Canty was the son of poor parents and had very... clothes. 6. There is tool... soup in my plate. Give me some more, please. 7. The children returned from the wood very sad because they had found very... mushrooms. 8. There was too... light in the room, and I could not read. There are very... people who don't know that the earth is round.

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Machine Elements

Screw fastenings

Machine parts are held together by parts:

a)  working in tension,

b)  working in shear,

c)  creating friction, and

d)   using both shear and friction forces.

Types of Fastenings-All fastenings can be divided into two classes- disconnectable fastenings and permanent joints.

Disconnectable fastenings, in turn are effected by:

a) bolts and screws

b) b) wedges

c) c) dowel pins

d) d) keys

Permanent joints are obtained by means of:

a) press fits

b) shrink fits

 c) rivets

d) welding, brazing, and soldering

E) casting

Forms if Threads. Screw fastenings are used for holding two or more machine parts together or for adjusting one part with relation to another. In screw fastenings the threads are made in several forms but are always of triangular-type single thread.

Screw threads are made right-hand and left- hand.

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Свеча зажигания — устройство для воспламенения топливно-воздушной смеси в самых разнообразных тепловых двигателях. Бывают искровые, дуговые, накаливания, каталитические. В бензиновых двигателях внутреннего сгорания используются искровые свечи.

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PINS.

Geometrically pins can be divided into cylindrical pins, called straight pins, and conical or taper pins. Dynamically pins can be classified as those used only to locate the relative position of two parts when there is little or no force acting upon the pin, and those that fasten two or more parts together and are subjected to considerable stresses, which are mostly in shear but sometimes in bending. Locating pins are called dowel pins or simply dowels. A connecting pin, like a dowel, may be used either as a permanent connection or as a fulcrum for a movable joint.

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Комбинированный двигатель внутреннего сгорания (комбинированный ДВС) — двигатель внутреннего сгорания, представляющий собой комбинацию из поршневой (роторно-поршневой) и лопаточной машины (турбина, компрессор), в котором в осуществлении рабочего процесса участвуют обе машины.

Ce of his destination.

 III. Use little or few.

 1. I have... time, so I can't go with you. 2. He has... English books. 3. There is... ink in my pen. Have you got any ink? 4. There are... bears in the zoo. 5. Tom Canty was the son of poor parents and had very... clothes. 6. There is tool... soup in my plate. Give me some more, please. 7. The children returned from the wood very sad because they had found very... mushrooms. 8. There was too... light in the room, and I could not read. There are very... people who don't know that the earth is round.

Контрольная работа №9

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KEYS

Types of keys.-The main function of a key is to transmit torque between a shaft and a machine part assembled on it. In most cases keys prevent relative motion, both rotary and axial. In some constructions keys allow an axial motion between the shaft and the hub, such keys are called feather or spline keys. In spite of the tendency to standardize there are many key types in use by various manufacturers.

According to various characteristics keys can be distinguished as straight and tapered; rectangular, dovetailed, chamfered round, and disk- shaped: radial and tangential; and (according to their use) for light duty and for heavy duty