带水的成语
英文资料
Suspension
Suspension is the term given to the system of springs, shock absorbers and linkages that connects a vehicle to its wheels. Suspension systems rve a dual purpo – contributing to the car's roadholding/handling and braking for good active safety and driving pleasure, and keeping vehicle occupants comfortable and reasonably well isolated from road noi, bumps, and vibrations,etc. The goals are generally at odds, so the tuning of suspensions involves finding the right compromi. It is important for the suspension to keep the road wheel in contact with the road surface as much as possible, becau all the forces acting on the vehicle do so through the contact patches of the tires. The suspension also protects the vehicle itlf and any cargo or luggage from damage and wear. The design of front and rear suspension of a car may be different.
猪图Leaf springs have been around since the early Egyptians.仓鼠笼子最佳选择
元气满满可爱的句子Ancient military engineers ud leaf springs in the form of bows to power their siege engines, with little success at first. The u of leaf springs in catapults was later refined and made to work years later. Springs were not only made of metal, a sturdy tree branch could be ud as a spring, such as
with a bow.
Hor drawn vehicles
By the early 19th century most British hor carriages were equipped with springs; wooden springs in the ca of light one-hor vehicles to avoid taxation, and steel springs in larger vehicles. The were made of low-carbon steel and usually took the form of multiple layer leaf springs.[1]
The British steel springs were not well suited for u on America's rough roads of the time, and could even cau coaches to collap if cornered too fast. In the 1820s, the Abbot Downing Company of Concord, New Hampshire developed a system whereby the bodies of stagecoaches were supported on leather straps called "thoroughbraces", which gave a swinging motion instead of the jolting up and down of a spring suspension (the stagecoach itlf was sometimes called a "thoroughbrace")
Automobiles
Automobiles were initially developed as lf-propelled versions of hor drawn vehicles. However, hor drawn vehicles had been designed for relatively slow speeds and their suspension was not well suited to the higher speeds permitted by the internal combustion engine.奇妙的旅行
西湖十景是哪十景
In 1903 Mors of Germany first fitted an automobile with shock absorbers. In 1920 Leyland ud torsion bars in a suspension system. In 1922 independent front suspension was pioneered on the Lancia Lambda and became more common in mass market cars from 1932.[2]
Important properties
Spring rate
The spring rate (or suspension rate) is a component in tting the vehicle's ride height or its location in the suspension stroke. Vehicles which carry heavy loads will often have heavier springs to compensate for the additional weight that would otherwi collap a vehicle to the bottom of its travel (stroke). Heavier springs are also ud in performance applications where the loading conditions experienced are more extreme.
Springs that are too hard or too soft cau the suspension to become ineffective becau they fail to properly isolate the vehicle from the road. Vehicles that commonly experience suspension loads heavier than normal have heavy or hard springs with a spring rate clo to the upper limit for that vehicle's weight. This allows the vehicle to perform properly under a heavy load when control is limited by the inertia of the load. Riding in an empty truck ud for carrying loads can be uncomforta
餐饮点评
ble for pasngers becau of its high spring rate relative to the weight of the vehicle. A race car would also be described as having heavy springs and would also be uncomfortably bumpy. However, even though we say they both have heavy springs, the actual spring rates for a 2000 lb race car and a 10,000 lb truck are very different. A luxury car, taxi, or pasnger bus would be described as having soft springs. Vehicles with worn out or damaged springs ride lower to the ground which reduces the overall amount of compression available to the suspension and increas the amount of body lean. Performance vehicles can sometimes have spring rate requirements other than vehicle weight and load.
Mathematics of the spring rate
Spring rate is a ratio ud to measure how resistant a spring is to being compresd or expanded during the spring's deflection. The magnitude of the spring force increas as deflection increas according to Hooke's Law. Briefly, this can be stated as
where
F is the force the spring exerts
k is the spring rate of the spring.
x is the displacement from equilibrium the length at which the spring is
neither compresd or stretched.
Spring rate is confined to a narrow interval by the weight of the vehicle,load the vehicle will carry, and to a lesr extent by suspension geometry and performance desires.
Spring rates typically have units of N/mm (or lbf/in). An example of a linear spring rate is 500 lbf/in. For every inch the spring is compresd, it exerts 500 lbf. A non-linear spring rate is one for which the relation between the spring's compression and the force exerted cannot be fitted adequately to a linear model. For example, the first inch exerts 500 lbf force, the cond inch exerts an additional 550 lbf (for a total of 1050 lbf), the third inch exerts another 600 lbf (for a total of 1650 lbf). In contrast a 500 lbf/in linear spring compresd to 3 inches will only exert 1500 lbf.
The spring rate of a coil spring may be calculated by a simple algebraic equation or it may be measured in a spring testing machine. The spring constant k can be calculated as follows:
where d is the wire diameter, G is the spring's shear modulus (e.g., about 12,000,000 lbf/in²or 80 GPa for steel), and N is the number of wraps and D is the diameter of the coil.
Wheel rate
Wheel rate is the effective spring rate when measured at the wheel. This is as oppod to simply measuring the spring rate alone.
Wheel rate is usually equal to or considerably less than the spring rate. Commonly, springs are mounted on control arms, swing arms or some other pivoting suspension member. Consider the example above where the spring rate was calculated to be 500 lbs/inch, if you were to move the wheel
1 inch (without moving the car), the spring more than likely compress
a smaller amount. Lets assume the spring moved 0.75 inches, the lever arm ratio would be 0.75 to 1. The wheel rate is calculated by taking the square of the ratio (0.5625) times the spring rate. Squaring the ratio is becau the ratio has two effects on the wheel rate. The ratio applies to both the force and distance traveled.
Wheel rate on independent suspension is fairly straight-forward. However, special consideration must be taken with some non-independent suspension designs. Take the ca of the straight axle. When viewed from the front or rear, the wheel rate can be measured by the means above. Yet becau the wheels are not independent, when viewed from the side under acceleration or braking the pivot point is at infinity (becau both wheels have moved) and the spring is directly inline with the wheel contact patch. The result is often that the effective wheel rate under cornering is different from what it is under acceleration and braking. This variation in wheel rate may be minimized by locating the spring as clo to the wheel as possible.
Roll couple percentage
Roll couple percentage is the effective wheel rates, in roll, of each axle of the vehicle just as a ratio of the vehicle's total roll rate. Roll Couple Percentage is critical in accurately balancing the handling of a vehicle. It is commonly adjusted through the u of anti-roll bars, but can also be changed through the u of different springs.
朝多音字组词A vehicle with a roll couple percentage of 70% will transfer 70% of its sprung weight transfer at the front of the vehicle during cornering. This is also commonly known as "Total Lateral Load Transfer Distribution" or "TLLTD".
Weight transfer
Weight transfer during cornering, acceleration or braking is usually calculated per individual wheel and compared with the static weights for the same wheels.
The total amount of weight transfer is only affected by 4 factors: the distance between wheel centers (wheelba in the ca of braking, or track
