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Automotive Suspension Design
Automotive suspension design is an aspect of automotive engineering, concerned with designing the suspension for cars and trucks. Suspension design for other vehicles is similar, though the process may not be as well established. The process entails *Selecting appropriate vehicle level targets *Selecting a system architecture *Choosing the location of the 'hard points', or theoretical centres of each ball joint or bushing *Selecting the rates of the bushings *Analysing the loads in the suspension *Designing the spring rates *Designing shock absorber characteristics *Designing the structure of each component so that it is strong, stiff, light, and cheap *Analysing the vehicle dynamics of the resulting design Since the 1990s the use of multibody simulation and finite element software has made this series of tasks more straightforward. Vehicle level targets A partial list would include: *Maximum steady state lateral acceleration (in understeer mode) *Roll stiffness (degr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Automotive Engineering
Automotive engineering, along with aerospace engineering and naval architecture, is a branch of vehicle engineering, incorporating elements of mechanical, electrical, electronic, software, and safety engineering as applied to the design, manufacture and operation of motorcycles, automobiles, and trucks and their respective engineering subsystems. It also includes modification of vehicles. Manufacturing domain deals with the creation and assembling the whole parts of automobiles is also included in it. The automotive engineering field is research intensive and involves direct application of mathematical models and formulas. The study of automotive engineering is to design, develop, fabricate, and test vehicles or vehicle components from the concept stage to production stage. Production, development, and manufacturing are the three major functions in this field. Disciplines Automobile engineering Automobile engineering is a branch study of engineering which teaches manufacturi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double Wishbone Suspension
A double wishbone suspension is an independent suspension design for automobiles using two (occasionally parallel) wishbone-shaped arms to locate the wheel. Each wishbone or arm has two mounting points to the chassis and one joint at the knuckle. The shock absorber and coil spring mount to the wishbones to control vertical movement. Double wishbone designs allow the engineer to carefully control the motion of the wheel throughout suspension travel, controlling such parameters as camber angle, caster angle, toe pattern, roll center height, scrub radius, scuff and more. Implementation The double-wishbone suspension can also be referred to as "double A-arms", though the arms themselves can be A-shaped, L-shaped, or even a single bar linkage. A single wishbone or A-arm can also be used in various other suspension types, such as variations of the MacPherson strut. The upper arm is usually shorter to induce negative camber as the suspension jounces (rises), and often this arrange ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toe Control
Toes are the digits (fingers) of the foot of a tetrapod. Animal species such as cats that walk on their toes are described as being '' digitigrade''. Humans, and other animals that walk on the soles of their feet, are described as being '' plantigrade''; ''unguligrade'' animals are those that walk on hooves at the tips of their toes. Structure There are normally five toes present on each human foot. Each toe consists of three phalanx bones, the proximal, middle, and distal, with the exception of the big toe ( la, hallux). For a minority of people, the little toe also is missing a middle bone. The hallux only contains two phalanx bones, the proximal and distal. The joints between each phalanx are the interphalangeal joints. The proximal phalanx bone of each toe articulates with the metatarsal bone of the foot at the metatarsophalangeal joint. Each toe is surrounded by skin, and present on all five toes is a toenail. The toes are, from medial to lateral: * the first toe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer-aided Design
Computer-aided design (CAD) is the use of computers (or ) to aid in the creation, modification, analysis, or optimization of a design. This software is used to increase the productivity of the designer, improve the quality of design, improve communications through documentation, and to create a database for manufacturing. Designs made through CAD software are helpful in protecting products and inventions when used in patent applications. CAD output is often in the form of electronic files for print, machining, or other manufacturing operations. The terms computer-aided drafting (CAD) and computer aided design and drafting (CADD) are also used. Its use in designing electronic systems is known as '' electronic design automation'' (''EDA''). In mechanical design it is known as ''mechanical design automation'' (''MDA''), which includes the process of creating a technical drawing with the use of computer software. CAD software for mechanical design uses either vector-based graphic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bump Steer
Bump steer is the term for the tendency of the wheel of a car to steer itself as it moves through the suspension stroke. Bump steer causes a vehicle to turn itself when one wheel hits a bump or falls down into a hole or rut. Excessive bump steer increases tire wear and makes the vehicle more difficult to handle on rough roads. For example, if the front left wheel rolls over a bump it will compress the suspension on that corner and automatically rotate to the left (toe out), causing the car to turn itself left momentarily without any input from the steering wheel. Another example, is that when most vehicles become airborne their front wheels will noticeably toe in. Rear suspension can be designed a number of ways. Many modern vehicles have rear suspension designs which are opposite of the front suspension: Toe in under bump, and out under droop. They can also be designed to have very little or no bump steer at all. Cars with rear live axles, also known as solid axles do not exhib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motion Ratio
The motion ratio of a mechanism is the ratio of the displacement of the point of interest to that of another point. The most common example is in a Suspension (vehicle), vehicle's suspension, where it is used to describe the displacement and forces in the spring (device), springs and shock absorbers. The force in the spring is (roughly) the vertical force at the contact patch divided by the motion ratio, and the spring rate is the wheel rate divided by the motion ratio squared. :IR = \frac.MR = \frac. :Wheel rate = *.Wheel rate = /. This is described as the Installation Ratio in the reference. Motion ratio is the more common term in the industry, but sometimes is used to mean the inverse of the above definition. Motion ratio in suspension of a vehicle describes the amount of shock travel for a given amount of wheel travel. Mathematically, it is the ratio of shock travel and wheel travel. The amount of force transmitted to the vehicle chassis reduces with increase in motion rati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scrub Radius
The scrub radius is the distance in front view between the king pin axis and the center of the contact patch of the wheel, where both would theoretically touch the road. It can be positive, negative or zero. The kingpin axis also known as steering inclination is the line between the upper and lower pivot points of the steering knuckle. If the kingpin axis intersection point is outboard of the center of the contact patch, it is negative; if inside the contact patch, it is positive. The term scrub radius derives from the fact that either in the positive or negative mode, the tire does not turn on its centerline (it scrubs the road in a turn) and due to the increased friction, more effort is needed to turn the wheel. Large positive values of scrub radius, 4 inches/100 mm or so, were used in cars for many years. The advantage of this is that the tire rolls as the wheel is steered, which reduces the effort when parking, provided you're not on the brake. The advantage of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kingpin (automotive Part)
The kingpin (also king-pin, king pin and k pin) is the main pivot in the steering mechanism of a car or other vehicle. The term is also used to refer to part of a fifth wheel coupling apparatus for a semi and its trailer or other load. History Originally, with the 'turntable' steering of horse-drawn wagons, this was a single pin on which the moveable axle was pivoted beneath the wagon's frame. This located the axle from side to side, but the weight of the wagon was carried on a circular wooden ring turntable surrounding this. Similar centre pivot steering was used by steam traction engines, the kingpin being mounted on the 'perch bracket' beneath the boiler. Some early cars also used centre pivot steering, although it became apparent that it was unsuitable for their increasing speeds. Ackermann steering separates the steering movement into two pivots, one near the hub of each front wheel. The beam axle between them remains fixed relative to the chassis, linked by the suspen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Roll Center
The roll center of a vehicle is the notional point at which the cornering forces in the suspension are reacted to the vehicle body. There are two definitions of roll center. The most commonly used is the geometric (or kinematic) roll center, whereas the Society of Automotive Engineers uses a force-based definition.An Introduction to Modern Vehicle Design edited by Julian Happian-Smith P293 Definition * Geometric roll center is solely dictated by the suspension geometry, and can be found using principles of the instant center of rotation. * Force based roll center, according to the US Society of Automotive Engineers, is "The point in the transverse vertical plane through any pair of wheel centers at which lateral forces may be applied to the sprung mass without producing suspension roll". The lateral location of the roll center is typically at the center-line of the vehicle when the suspension on the left and right sides of the car are mirror images of each other. The si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caster Angle
250px, θ is the caster angle, the red line is the pivot line, and the grey area is the tire. 250px, Front suspension of a race car, the caster angle is formed by the line between upper and lower ball joint. The caster angle or castor angle is the angular displacement of the steering axis from the vertical axis of a steered wheel in a car, motorcycle, bicycle, other vehicle or a vessel, as seen from the side of the vehicle. The steering axis in a car with dual ball joint suspension is an imaginary line that runs through the center of the upper ball joint to the center of the lower ball joint, or through the center of the kingpin for vehicles having a kingpin. Caster causes a wheel to align with the direction of travel, and can be accomplished either by caster displacement or caster angle. Caster displacement moves the steering axis ahead of the axis of wheel rotation, as with the front wheels of a shopping cart. Caster angle moves the steering axis from vertical. In automob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camber Angle
Camber angle is one of the angles made by the wheels of a vehicle; specifically, it is the angle between the vertical axis of a wheel and the vertical axis of the vehicle when viewed from the front or rear. It is used in the design of steering and suspension. If the top of the wheel is farther out than the bottom (that is, tilted away from the axle), it is called positive camber; if the bottom of the wheel is farther out than the top, it is called negative camber. Effect on handling Camber angle alters the handling qualities of some suspension designs; in particular, negative camber improves grip in corners especially with a short long arms suspension. This is because it places the tire at a better angle to the road, transmitting the centrifugal forces through the vertical plane of the tire rather than through a shear force across it. The centrifugal (outwards) force is compensated for by applying negative camber, which turns the contact surface of the tire outwards to mat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toe (automotive)
In automotive engineering, toe, also known as tracking, is the symmetric angle that each wheel makes with the longitudinal axis of the vehicle, as a function of static geometry, and kinematic and compliant effects. This can be contrasted with steer, which is the antisymmetric angle, i.e. both wheels point to the left or right, in parallel (roughly). Negative toe, or toe out, is the front of the wheel pointing away from the centreline of the vehicle. Positive toe, or toe in, is the front of the wheel pointing towards the centreline of the vehicle. Historically, and still commonly in the United States, toe was specified as the linear difference (either inches or millimeters) of the distance between the two front-facing and rear-facing tire centerlines at the outer diameter and axle-height; since the toe angle in that case depends on the tire diameter, the linear dimension toe specification for a particular vehicle is for specified tires. Description In a rear-wheel drive vehicl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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