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What is torque steer?

The reason why the front-drive will become the mainstream production car, because it reduces the maximum mechanical space, the passenger has the most spacious seating space, eliminating the need for the drive shaft can save manufacturers a lot of cost. Moreover, for ordinary driving, the front-drive after drive has a relatively better handling, slippery surfaces less prone to slipping. But everything always good foundation, that when the transverse engine horsepower is getting bigger, the problem will gradually appear. Because the FF vehicle steering shaft and responsible for power transmission, but because of the position of the gearbox, often a long shaft around a shorter design, when suddenly a large torque output from the transmission output shaft to approximately when the two drive shafts, because of the different moments and will cause deviation direction of travel of the vehicle, which is the so-called torque steer. In other words, the main factors causing the steering torque is instead of driving, because the torque output is too large, thus causing the vehicle “non-autonomous driver” steering.

1. Of torque steer Glossary

The reason why the front-drive will become the mainstream production car, because it reduces the maximum mechanical occupy emptyInter, the passenger has the most spacious seating space, eliminating the need for drive shaft can also save a lot of costs for the manufacturers. Moreover, for ordinary driving, the front-drive after drive has a relatively better handling, slippery surfaces less prone to slipping.

but everything is always good foundation, that when the transverse engine horsepower is getting bigger, the problem will gradually appear. Because the FF vehicle steering shaft and responsible for power transmission, but because of the position of the gearbox, often a long shaft around a shorter design, when suddenly a large torque output from the transmission output shaft to approximately when the two drive shafts, because of the different moments and will cause deviation direction of travel of the vehicle, which is the so-called torque steer. In other words, the main factors causing the steering torque is instead of driving, because the torque output is too large, thus causing the vehicle “non-autonomous driver” steering.

2. The cause of torque steer

about why not wait a long drive shaft transmitting torque can cause different result? The reason for the suspension and gimbal is the culprit.

First, the geometry FF vehicle drive shaft and axle are not coincident, turn the drive shaft to bend in order to connect two small wheels, turning the place, it is connected by the universal joint. Although the joint may vary movable transmission direction, but the joint is not a panacea, Flanagan shaft after the change in direction of the drive shaft is changed while the direction will have some swinging, so to install an anti-whip since stable fulcrum effect, if there is no fixed pivot, the rear endDrive shaft will be swinging like a blender same.

When the drive shaft universal preganglionic out of line, the joint must rely on the swinging fulcrum reaction force is converted into a torsional force, but as long as the friction joint consumption control properly, universal joint torque transmission efficiency is very high, especially in the case of changing the small angle drive, torque about the differences may be caused by friction loss is very small.

When the left and right drive shafts of unequal length, about gimbal drive angle is not the same at both ends, the greatest impact is anti-swinging fulcrum by the force magnitude, the force is directly SIN function is proportional to the angle of the drive, this function is sensitive at an angle close to 180 degrees near the angle changes. Meanwhile, since the fulcrum is fixed on the suspension, the suspension is a certain degree of freedom, when the car is accelerating, due to the shift of the center of gravity, a relatively small amount of the front elevation, time, before the shock absorbing cylinder is elongated, side short shaft angle change is large, under the action of the torsion relatively large amplitude extending in the front wheel, the vehicle front suspension FF are many forms McPherson, shock-absorbing wheel cylinder itself is supported axis, it will produce a change if the front wheel extends camber angle, a slight change in the camber angle can be changed wheel contact points, so torque steer effect is likely to be enlarged.

long, the same angle on both sides of the drive, then this action can be effectively suppressed if the two ends of the drive shaft into the like. It will not change if the wheel camber reach, then the torque steer effect will not have been over-amplification, the problem is not so serious. Simply put, due to the increase in violent engine power output, universal joints caused by different due to the different angles of transmission efficiency, and because of increased engine power output violently, increase the speed, the front suspension is stretched, causing a small camber angle change, the more magnified the problem, eventually leading to the occurrence of torque steer.

Now, the problem has been solved, Magotan axle design purpose is to prevent the occurrence of torque steer when excessive torque will be broken axle. Engineers will select Geshitu longer axle design into two sections, an increase of some intermediate shaft, which allows an equal length on both sides of the axle, weaken torque steer, which is used in most of today FF ​​car design the way.

3. How to avoid torque steer

To solve the problem of torque steer FF car, the best that can be made as long as the drive shaft, Subaru’s symmetrical drivetrain is the case, both front and rear, left and right shaft length, etc., or with precise and multi-link double-wishbone front suspension, camber change can be suppressed, the maximum torque steer alleviate the problems of modern electronics may also be used to control left and right wheel torque adjust relatively the same, it can greatly reduce the occurrence of torque steer.

In fact, the mechanical structure of the layout, the left and right front drive axle same can be done as long as only the beginning of plant design trade-offs are through, usually the civilian car (car to be preoccupied with perfect control, so extreme, it is not within this range) just to the left and right axle shafts of equal length and modify the differential gear box arrangement, the consequences will affect the engine position, form and space engine compartment economy and so on use, it is obviously worth the candle.

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