suspension

suspension,

in automobiles, system of springs used to suspend the frame, body, engine, and power train above the wheels. Its principal purpose is to lessen the jarring of the automobile that is caused by irregularities in the roads traveled. Since the wheels of an automobile accelerate, stop, and steer it, the suspension must also serve to keep the wheels in close contact with the road surface at all times. The types of springs used in suspensions include leaf springs, coil springs, torsion bars, and air springs. There have been many refinements in modern suspensions. On most vehicles the front wheels are suspended independently, i.e., the front axle has been eliminated. Certain vehicles also have the rear wheels suspended independently. Hydraulic shock absorbers have been included to prevent the springs from shaking the automobile excessively after a jolt. An elaborate system of mechanical linkages is often included to position the mass of the vehicle accurately with respect to its wheels during accelerating, braking, and steering.

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suspension,

in chemistry, mixture of two substances, one of which is finely divided and dispersed in the other. Common suspensions include sand in water, fine soot or dust in air, and droplets of oil in air. A suspension is different from a colloid or solution. Particles in a suspension are larger than those in colloids or solutions; they are visible under a microscope, and some can be seen with the naked eye. Particles in a suspension precipitate if the suspension is allowed to stand undisturbed.

The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Suspension

 

of vehicles, the system of parts and mechanisms to connect the support elements (wheels, rollers, or skis) to the body of the vehicle, designed to reduce the dynamic load and ensure even distribution of the load to the support elements during movement, with a secondary purpose of increasing the traction characteristics of the vehicle.

There are three types of suspension—rigid, semirigid, and soft. With rigid suspension, which is used for tracklaying hoisting cranes, excavators, peat combines, and other vehicles with traveling speeds of not more than 3-4 km/hr, the axles of the support rollers are secured directly to the frame without any intermediary moving parts. With semirigid suspension, which is used on most types of tractors, the support rollers are mounted on special frames (tracklaying wagons), which are usually connected to the frame by a hinge in back and an elastic element, such as a spring, in front or by elastic elements both front and back. Soft, or elastic, suspension, which is used for cars, other high-speed vehicles, and some kinds of tractors, has a large reserve of potential energy— that is, considerable motion and quite sufficient rigidity.

In terms of design, motor vehicle suspension may be conventional or independent. In conventional suspension a rigid bar (the front axle or the rear axle housing) connects the elastic elements with the wheels. In independent suspension, there is a special guide apparatus (rocker arms or posts) for each elastic element that connects the suspended part of the vehicle with a wheel. Therefore, the right and left wheels of the same axle have independent vertical movement.

A vehicle may have flat spring, coil spring, torsion bar, and pneumatic suspensions. Flat, or leaf, springs are usually used in the conventional suspension of trucks and in the rear suspension of certain cars. Elastic elements in the form of coil springs and torsion bars are used in the independent front suspension of cars. The elastic elements used in the pneumatic suspension of buses, such as the LAZ-695, are cylinders filled with compressed air whose pressure is maintained by a regulator that increases the delivery of compressed air from the pneumatic system when the load on the cylinder increases, thus ensuring consistent road clearance. To lessen the amplitude of rocking and to damp it quickly, shock absorbers are included in the suspension system. The movement of the suspension is restricted by rubber limiters. The suspension systems of some vehicles are equipped with stabilizers to limit pitching on turns and body swaying while the vehicle is moving.

The suspension of railroad rolling stock—locomotives and railroad cars— is often called spring suspension; it includes elastic elements, such as flat springs (bearing, full elliptic, air, and rubber) and coil springs (helical, ring, disc, and others), as well as hydraulic and friction shock absorbers to restrict vibration. The suspension may have one, two, or three stages depending on the required degree of suppression of the forces from the running gear of the locomotive or railroad car that are acting on the frame.

I. G. GERTSKIS, A. A. SABININ, AND B. N. POKROVSKII

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Suspension

 

a disperse system consisting of solid particles (the dispersed phase) distributed in a liquid dispersion medium. Suspensions are coarsely disperse systems with particle sizes of 10^–4 cm and larger. Structureless suspensions are unstable with regard to sedimentation, since the particles are precipitated by gravity. (In Russian, suspensions in which the particles settle very slowly are sometimes called vzvesi rather than suspenzii.)

Suspensions can be formed by dispersing solids in liquid mediums or by mixing dry powders with liquids. They also arise from the aggregation of colloid particles during coagulation or condensation. In nature, suspensions are formed when soils are eroded by water or when bodies of water are contaminated by atmospheric dust. Pulp and drilling mud are typical suspensions.

Suspensions are widely used in construction and in the manufacture of ceramics, plastics, paints, varnishes, and paper. Some fertilizers and pesticides and many drugs are used in the form of suspensions.

L. A. SHITS

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

suspension

[sə′spen·shən]

(chemistry)

A mixture of fine, nonsettling particles of any solid within a liquid or gas, the particles being the dispersed phase, while the suspending medium is the continuous phase. Also known as suspended solids.

(engineering)

A fine wire or coil spring that supports the moving element of a meter.

(mining engineering)

The bolting of rock to secure fragments or sections, such as small slabs barred down after blasting blocks of rock broken by fracture or joint patterns, which may subsequently loosen and fall.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

suspension

1. Law

a. a postponement of execution of a sentence or the deferring of a judgment, etc.

b. a temporary extinguishment of a right or title

2. a system of springs, shock absorbers, etc., that supports the body of a wheeled or tracked vehicle and insulates it and its occupants from shocks transmitted by the wheels

3. a device or structure, usually a wire or spring, that serves to suspend or support something, such as the pendulum of a clock

4. Chem a dispersion of fine solid or liquid particles in a fluid, the particles being supported by buoyancy

5. the process by which eroded particles of rock are transported in a river

6. Music one or more notes of a chord that are prolonged until a subsequent chord is sounded, usually to form a dissonance

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

suspension

In lazy evaluation, a suspension (or in Henderson's terminology, a "recipe") is a closure with a flag indicating whether the expression has been evaluated or not. When the expression is evaluated the first time, this flag is set. Subsequent requests for the value of the expression will not attempt to re-evaluate it.

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