anti-scroll bars ( roller bar , anti-shake bar , bar bar , stabilizer ) is part of many car suspensions that help reduce vehicle body roll during fast cornering or road irregularities. It connects the opposite (left/right) wheel together through a short lever arm connected by the torsion spring. A shake rod increases the stiffness of the suspension roll - its resistance to take turns, independent of its spring rate in the vertical direction. The first stabilizer bar patent was awarded to Canadian inventor Stephen Coleman of Fredericton, New Brunswick on April 22, 1919.
Anti-roll bars are not uncommon on pre-war cars because suspensions are generally more rigid and reception body roll. From the 1950s on, production cars were more often fitted with anti-roll bars, especially vehicles with softer coil spring suspensions.
Video Anti-roll bar
Goals and operations
An anti-rolling or anti-roll bar is intended to force each side of the vehicle to lower, or rise, to the same height, to reduce the tilted slant (reel) of the vehicle on a curve, sharp angle or large bulge, essentially negating the centrifugal force of the rounded vehicle curve. With the blades removed, the wheels of the vehicle can be tilted away at a much larger distance ( as shown by the right SUV image ). Although there are many variations in the design, a common function is to force the opposing wheel shock absorbers, springs or suspension rods to lower, or rise, to the same level as the other wheels. In quick spins, a vehicle tends to fall closer to the outer wheels, and the sway bar immediately forces the opposing wheel to also be closer to the vehicle. As a result, vehicles tend to "hug" the path closer in a fast spin, where all the wheels are closer to the body. After a rapid turnover, downward pressure is reduced, and the paired wheel can return to their normal height of the vehicle, kept at the same level as the connecting rocking bar.
Because each pair of wheels is crosslinked with a bar, the combined operation causes all wheels to generally offset the slope apart from the rest and the vehicle tends to remain flat with the general tilt of the field.
Maps Anti-roll bar
Principles
A bar shake is usually a torsion spring that rejects the body roll movement. Usually made of a cylindrical steel rod, formed into a "U" shape, which connects to the body at two points, and on the left and right sides of the suspension. If the left and right wheels move together, the bar rotates around the fixing point. If the wheels move relative to each other, the bars are subjected to torque and forced to rotate. Each end of the bar is connected to the end link via a flexible connection. The shake end joint connecting alternately to the point near the wheel or the shaft, transferring the power from the highly charged shaft to the opposite side.
Troop transferred:
- from the loaded axis
- to the linked end link via bushing
- on the anti-sway (torsion) bar via flexible connection
- to the connected end link on the opposite side of the vehicle
- to the opposite axis.
The rod retains the torque through its stiffness. The rigidity of the anti-roll bar is proportional to the stiffness of the material, the strength of the four of its fingers, and the opposite of the length of the lever's arm (ie, the shorter the lever arm, the rigid bar). Stiffness is also related to the geometry of the mounting points and the stiffness of the rod pin points. The more rigid the bars, the more force it takes to move the left and right wheels relative to each other. This increases the amount of power needed to make body rolls.
In turn, the mass emerging from the vehicle body produces a lateral force in the center of gravity (CG), proportional to lateral acceleration. Since CG is usually not on the axis of the roll, the lateral force creates a moment around the axis of the roll that tends to curl the body. (The axis of the reel is the line connecting the center of the front and back windings). Currently called a roll partner.
The spool coil is opposed by the stiffness of the suspension roll, which is a function of the spring rate of the vehicle springs and anti-roll bars, if any. The use of an anti-roll bar allows designers to reduce the roll without making the suspension springs more rigid in the vertical plane, allowing increased body control by reducing the quality of the ride.
One of the slim body effects, for typical suspension geometry, is the positive camber of the wheel on the outside of the turn and the negative on the inside, which reduces their cornering grip (especially with the cross-ply tires).
Primary function
Anti-roll bar provides two main functions. The first function is a lean body reduction. The reduction of the slim body depends on the stiffness of the total roll of the vehicle. Increasing the total roll stiffness of the vehicle does not alter the total loading (weight) of the steady load from the inner wheels to the outer wheels, only reducing the slim body. Total lateral load transfer is determined by the height of CG and the trajectory width.
Another function of anti-roll bars is to set the balance of car handling. The understeer or oversteer behavior can be tuned out by changing the total proportion of roll stiffness that comes from the front and rear axles. Increasing the proportion of stiffness of the roll in front increases the proportion of total load displacement caused by the front axle - and decreases the proportion shifted by the rear axle. In general, it keeps the outer front wheel running at a relatively higher slip angle, and the outer rear wheels for running at relatively lower slip angles, which are the understeer effect. Increasing the proportion of the stiffness of the roll on the rear axle has the opposite effect and lowers the understeer.
Weakness
Because the anti-bolster blades connect the wheel on the opposite side of the vehicle, the blades emit the power of the bulge on one wheel to the opposite wheel. On rough or broken sidewalks, the anti-roll bar can produce wobble, side-to-side body movement ("wobbling" sensation), which increases the severity with the diameter and stiffness of the sway bar. Other suspension techniques may delay or dampen this effect from the connecting rod.
Excessive roll stiffness, usually achieved by configuring too aggressive anti-roll bars, can keep the inner wheels lifted off the ground during hard cornering. This can be used for profit: many front wheel production cars raise the rear wheels when cornering hard to overload the opposing wheel, limiting the understeer.
Customizable bar
Some anti-roll bars, especially those intended for use in auto racing, can be adjusted externally when the car is in the pit while some systems can be adjusted directly by the driver from the car, such as the Super GT. This allows stiffening to be changed, for example by increasing or decreasing the length of the lever arm on some systems, or by turning the lever arm flat from a rigid edge position to a more flexible side-side position on the other. system. This allows a mechanic to adjust the stiffness of the rolls to different situations without replacing the entire blade.
MacPherson struts
The MacPherson strut is a common form of strut suspension. This is not the first attempt at strut suspensions, but in MacPherson's original patent, the anti-roll bar forms an integral and important part of the suspension, in addition to the usual functions in controlling the body roll. A strut suspension like MacPherson's requires a lower bottom between the chassis and the wheel hub to control the wheel position both in and out (controlling the track), as well as forwards and back. This may be provided by wishbone with a number of joints, or by using an additional radius rod. The MacPherson design replaces the wishbone with a simpler, cheaper track control arm, with an inboard joint, to control the track. The forward and backward positions are controlled through an anti-roll bar. Overall, this requires a simpler and cheaper set of suspension members compared to wishbones, also allowing unsprung weight reduction.
Because the anti-roll bar is required to control the position of the wheel, MacPherson strut suspension rods can be connected through the ball joint. However many later "MacPherson strut" suspensions have returned using wishbones rather than the simplified track control arm of the original design.
Active system
The first to use an active anti-roll bar in 1994 was the Citroen Xantia Activa, an intermediate sedan sold in Europe. The SC.CAR system (Systeme CitroÃÆ'¡n de ContrÃÆ'Â'le Actif du Roulis) features an anti-roll bar that can be rigid under the ECU suspension command during hard cornering. Car rolled over 2 degrees.
In 2001 the BMW 7 Series (E65) introduced Active Roll Stabilization (ARS) "active anti-roll bar" which can be controlled proportionally by computer suspension control, reducing slim body interchangeably while improving rough road driving quality.
In 2006 Toyota introduced the Active Suspension Stabilizer System. By changing the stiffness of the stabilizer bar, the system works to reduce the tilt of the body during cornering, keeping the vehicle higher during turns and improving handling, compared to the natural propensity of the rotating vehicle due to lateral forces experienced during high-speed maneuvers. The active stabilizer system relies on vehicle body sensors and electric motors. The first production use of this system was introduced in August 2005 with the Lexus GS430 sports sedan
Porsche Panamera introduced the same system Porsche Dynamic Chassis Control (PDCC) in 2009.
Mercedes-Benz M-Class # Third generation (W166: 2011-present) introduced a similar system: ACTIVE KURVA SYSTEM in 2011.
Range Rover Sport introduces active anti-roll Dynamic Response bar.
The Mercedes-Benz S-Class Active Body Control System uses another approach: the computer uses sensors to detect lateral loads, lateral forces, and height differences in the suspension strut, then using hydraulic pressure to raise or lower the springs to the counter rollers. This system removes the anti-roll blades. The most active roll control system allows small rolls to give a more natural feel.
Toyota also uses a mechanical system called the Kinetic Dynamic Suspension System (KDSS) which essentially releases stabilized bars when off-road, allowing for greater vehicle articulation and quality of the vehicle.
See also
- Panhard rod
- Torque torque suspension
References
Source of the article : Wikipedia
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