Car Tech 101: Steering explained
A portion of the vehicle steering mechanism coupling rod, steering arm, the axis of the king pin using ball joints.
Management is the collection of components, links, etc., which allows any bicycle vehicle car motorcycle to follow the path desired An exception is the case of rail transport by which the railways combined together with the railway switches and also known as points in British English provide direction operate the main purpose of the steering system is to allow the driver to steer the vehicle.
The most conventional steering device is to rotate the front wheels by means of a steering wheel manually operated direction that is positioned in front of the driver through the steering column which may contain universal joints that can also be part of the foldable design steering column to allow it to deviate somewhat from a straight line other arrangements are sometimes found on different types of vehicles, for example, a steering bar or the rear wheel of tracked vehicles such as bulldozers and tanks usually employ differential steering that is, the tracks are made to move at different speeds, or even in opposite directions, using clutches and brakes to cause change of course or direction.
Θ caster angle indicates that the line of pivoting of the kingpin and the gray area indicates the vehicle tire with the wheel moving right to left auxiliary A positive rake angle in the directional stability that the wheel tends to drag, but a wide angle allows a more difficult direction.
The curves described by the rear wheels of a conventional motor when the vehicle moves at a constant speed of the inner and outer rear wheels are not.
The fundamental purpose of management is to ensure that the wheels are oriented in the desired directions This is typically done by a set of links, rods, pins and gears One of the fundamental concepts is that of the angle casting of each wheel is directed with a pivot point in front of the wheel; which makes steering tend to be self-centering in the direction of travel.
Steering transmission between the steering gear and the wheels generally conform to a variation of the Ackermann steering geometry to account for the fact that, in a turn, the inside wheel is actually moving a smaller radius path that the outer wheel, so that the degree of toe suitable for driving in a straight path is not suitable for turns the angle of the wheels make with the vertical plane also affects the dynamic steering see camber angle such as tires.
Rack and pinion, ball, worm and edit sector.
Rack and pinion steering mechanism steering wheel 1; 2 steering column; 3 rack and pinion; 4 connecting rod; 5 linchpin.
Rack and pinion unit mounted in the cockpit of a sports car Ariel Atom chassis, unusual cars of contemporary production.
Many modern cars use mechanisms steering rack and pinion, where the steering wheel turns the pinion; the pinion moves the rack, which is a linear gear which meshes with the pinion, converting a circular motion into a linear motion along the transverse axis of the car side lateral movement This movement applies a torque direction on the pivot axis joints that have replaced earlier used pins of the stub axle of the steered wheels via track rods and a short lever arm called steering arm.
Support and pinion design has the advantages of a high degree of feedback and direct steering feel a disadvantage is that it is not adjustable, so that when it bears and develop lash the only remedy is the replacement.
BMW began using steering systems and rack pinion in the 1930s, and many other European manufacturers adopted the technology US automakers have adopted rack and pinion steering, starting with the Ford Pinto 1974 1.
Older designs use two principles of the worm and sector design and the nuts and bolts Both have been improved by reducing friction; for the screw and the nut, it is the recirculating ball mechanism, which is always found in trucks and commercial vehicles The steering column rotates a big screw that engages with the nut of the recirculating ball the nut moves from one sector of a toothed wheel, causing it to rotate about its axis as the screw is rotated; an arm secured to the axis of the die moves Pitman arm which is connected to the steering linkage and thus steers the wheels version recirculating ball of this apparatus reduces the considerable friction by placing large ball bearings between the screw and nut; at each end of the apparatus, the output of balls between the two parts in an internal channel of the box that connects to the other end of the device, they are thus recirculated.
The mechanism recirculating ball has the advantage of a greater mechanical advantage so that it was found on larger, heavier vehicles while the rack and pinion was initially limited to smaller and more light; because of this is the almost universal adoption of power steering, however, more important advantage, leading to the increasing use of rack and pinion on new cars The ball circulation design also has a noticeable blow whip, or neutral on the area, where one minute turn the steering wheel in either direction does not move the steering apparatus; is easily adjustable by a screw at the end of the steering box to account for wear, but it can not be completely eliminated because it creates excessive internal forces at other positions and the very rapid wear mechanism this design is still in use in trucks and other large vehicles, where the speed of management and direct feel are less important than robustness, maintainability and mechanical advantage.
The worm and the area was an older model, used for example in the Willys and Chrysler, and Ford Falcon 1960 To reduce friction sector is replaced by a roller or rotary axes on the tree arm rocker.
Other control systems exist but are rare road vehicles children's toys and go-karts often use a direct link in the form of a puppet also commonly called Pitman arm tied directly between the steering column and arms management, and use of cable-operated steering linkages, eg capstan and bowstring mechanism is also found on some vehicles built at home such as soapbox cars and recumbent tricycles.
Power steering allows the driver of a vehicle to lead by directing a portion of its energy to help rotate the steering wheels around their axis directions As vehicles have become heavier and switched to FWD especially using geometry negative shift and increases tire width and diameter, the effort required to turn the wheels around their steering axis has increased, often to the point where physical effort is needed if it aid power to alleviate these car manufacturers have developed power steering systems, or more precisely, the power-assisted steering, because on the road going vehicles, there must be a mechanical connection as failsafe There are two types of systems power steering, and an electronic hybrid electric system an electric hydraulic is also possi corn.
A hydraulic power steering HPS uses hydraulic pressure provided by a pump driven by the engine to assist the rotational motion of the steering wheel electric power steering EPS is more efficient than the hydraulic power steering, because the electric power steering motor only needs to provide assistance when the steering wheel rotates, while the hydraulic pump must operate continuously in the EPS, the amount of the aid is easily tunable to the vehicle type, road speed, and even the driver's preference another advantage is the elimination of the environmental risks posed by leaks and eliminating the liquid water power steering Further, the electric assistance is not lost when the engine fails or stalls, then adopts a hydraulic assistance working if the engine is stopped, making the direction doubly heavy that the driver must now not only very heavy direction without any help, but also the electric assist system itself.
An outgrowth of the power steering is responsive steering gear, where the steering is heavily assisted at low speed and lightly helped Automakers high speed perceive that drivers might need to make large steering inputs while maneuvering for parking, but not while traveling at high speed the first vehicle with this feature was the Citroën SM with its layout Diravi, 2 rather than modifying the amount of aid as in modern power steering systems it has changed the pressure on a centering cam which makes the wheel trying to spring back straight power steering systems -ahead position sensitive modern speed reduces the mechanical or electrical assistance when the vehicle speed increases, which gives a more direct feel this function is gradually becoming more common.
Mud applicator agricultural assistance crab to minimize soil compaction, 2009.
Four-wheel steering system is employed by certain vehicles to improve the steering response, to increase the stability of the vehicle at a high speed maneuver, or to decrease the low-speed rotation radius.
In a steering system with four active wheel drive, the four wheels rotate at the same time when the driver steers in the steering systems four most active wheels, the rear wheels are guided by a computer and actuators 3 rear wheels generally can not turn since the front wheels There may be controls to turn off the rear steering and options to only steer the rear wheels independently of the front wheels at low speed parking, for example the rear wheels rotate at the opposite of the front wheels, reducing the turning radius, sometimes critical for large tractors trucks, vehicles with trailers and passenger cars with a long wheelbase, while at higher speeds both front and rear wheels turn controlled also well electronically, so that the vehicle can change position with less yaw and improve Accumulation of the lateral acceleration improving straight line stability 3 4 meandering effect experienced during motorway campaigns while towing a travel trailer is largely nullified discuss doubtful.
Steering-wheel drive finds its most widespread use in monster trucks where maneuverability in small arenas is critical, and it is also popular in large farm vehicles and lorries Some modern European Intercity buses also use the direction four wheels to help maneuverability in bus stations and also to improve road stability first rally car to use technology was the Peugeot 405 Turbo 16 His debut was at the Climb 1988 Pikes international Peak, where he set a time record 10 47 77 5 the car would continue to victory in the Paris-Dakar Rally in 1989 and 1990 again driven by Ari Vatanen.
Previously, Honda had the management four-wheel drive as an option in their 1987 2001 Prelude and models Honda Ascot Innova 1992 1996 Mazda also offered four-wheel steering on the 626 and MX6 in 1988 General Motors offers Quadrasteer Delphi in their Silverado Sierra consumption Suburban Yukon However, only 16,500 vehicles were sold with this system since its introduction in 2002 to 2004 due to the low demand, GM abandoned the technology at the end of the 2005 model year Nissan Infiniti 6 offers several versions of their HICAS system as standard or an option in much of their range.
In the late 2000s a new generation was introduced to the market of steering systems with four wheels in the first BMW with its 7 series with a wheel steering system option, called Integral Active Steering, which is now available on 7 current series 7 series 6 8 and 5 series 4 Renault option introduces an optional all-wheel steering called 4Control 9 10 11 in 2009, at first on Laguna GT is currently available on the Talisman 10 Mégane 9 and space 11 vehicle lines in 2013, Porsche first introduced a system on the 991 Turbo as standard equipment 12 Since 2016, the Porsche Panamera also comes with an optional steering-wheel drive Audi 13, launched the 2014 model with a Q7 system optional 14 Japanese OEM also offer luxury car segment equipped with all wheel, as its Infiniti QX70 model rrière Active Steering and 15 Lexus GS 16 on the OEM launched the Italian technology in model year 2016 with 17 Ferrari 17 Ferrari F12t df GTC4Lusso 18 and the Lamborghini Aventador Coupe S 19.
Car production with the active steering to the four wheels Edit.
Crab steering is a special type of active four-wheel steering It works by directing all wheels in the same direction and at the same crab steering angle is used when the vehicle is straight forward, but at an angle to -dire when moving loads with a reach truck, or during filming with a camera carriage, or when the rear wheels can not follow the wheel tracks forward to reduce compaction ie the ground when using the rolling farm equipment.
Many modern vehicles have passive rear steering of many vehicles, in turns, the rear wheels tend to slightly towards the outside of a turn, which can reduce the stability of the passive steering system uses the lateral forces generated in a turn by the suspension geometry and sockets to correct this trend and steer the wheels slightly inside the corner that improves the stability of the car, around the turn this effect is called understeer and compliance , or its opposite, is present on all suspensions of typical methods for compliance understeer is to use the Watt link on a rear axle in real time, or the use of end of control rings on a suspension torsion beam on a rear independent suspension, it is normally obtained by modifying the rubber rings rates in suspension C ome suspensions have typically accordance oversteer due to the geometry, such that the driving axles Hotchkiss or a semi-trailing arm IRS, but can be alleviated by revisions to the pivot points of the af spring or trailing arm.
Management passive rear wheel is not a new concept as it has been used for many years, but not always recognized as such.
Articulated steering is a system by which a vehicle with four driving wheels is divided into two front and rear halves which are connected by a vertical hinge, the front and rear halves are connected by one or more hydraulic cylinders which alter the angle between the halves including front and rear axles and wheels, steering and the vehicle This system does not use the steering arm, king pins, tie rods, etc. As four wheels If the vertical hinge is positioned midway between the two axles, it also eliminates the need for a center differential that both front and rear axles will follow the same path, and rotate and at the same speed articulated long road trains buses and trains internal transport trucks use management articulated to obtain smaller turning circles, comparable to those of more conventional vehicles court ts articulated trucks have very good off-road performance.
Steering rear wheel tends to be unstable, because in turn geometry changes direction thus reducing the turning radius oversteer, rather than increasing understeer steering rear wheel is designed for slow vehicles that require high maneuverability in tight spaces, forklifts e g.
1971 Lunar Roving Vehicle LRV with steering controls the joystick.
The purpose of the steer-by-wire technology is to completely eliminate the largest number of mechanical components steering shaft, column, gear reduction mechanism, etc. As possible the complete replacement of conventional steering system with steer- by-wire has several advantages, such as.
The absence of steering column simplifies the design of the interior of the car.
The absence of steering shaft, column and the reduction gear mechanism makes much better use of space in the engine compartment.
The steering mechanism may be designed and installed as a modular unit.
No mechanical connection between steering wheel and road wheel, it is less likely that the impact of a frontal collision will force the wheel to introduce in the driver's survival space.
Features of the steering system can easily and infinitely adjustable for optimum steering response and feel.
In 2007, there is no production of cars available that rely solely on the steer-by-wire technology because of the safety, reliability and economic concerns, but this technology has been demonstrated in numerous concept cars and similar fly-by-wire technology is in use in two applications of military and civil aviation Removing the mechanical steering linkage in road vehicles that will require new legislation in most countries.
For security reasons all modern cars feature a collapsible column energy absorbing steering steering column will collapse if heavy frontal impact to avoid excessive injuries to the driver airbags are also generally mounted standard columns nonfoldable management mounted on older vehicles very often impaled conductors in frontal collisions, particularly when the steering box or shelf has been mounted in front of the axle line before, at the front of the deformation zone This is particularly a problem with vehicles which have a framework of rigid separate frame without deformation zone most modern steering racks vehicle boxes are mounted behind the front axle of the front bulkhead, in back of the front crumple zone.
Collapsible steering columns were invented by Bela Barenyi and were introduced in the Mercedes-Benz W111 Fintail 1959, and crumple zones This safety feature appeared when the cars built by General Motors after an extensive lobbying campaign very public enacted by Ralph Nader Ford began installing collapsible steering columns in 1968 30.
Audi has used a wheel belt tensioning system and seat collapsible steering called Procon-ten, but it has since been abandoned in favor of airbags and pyrotechnic seat belt tensioners.
Ships and boats are generally oriented with a rudder according to the size of the vessel, the rudder can be manually actuated or actuated by means of a servomechanism or a boat trim tab servo system using outboard motors -bord steering by rotating the entire drive unit boats with inboard engines sometimes steer by rotating the propeller nacelle ie only Volvo Penta IPS drive modern ships thruster azimuth using diesel-electric drive boats driven by oars ie rowing boats, including gondolas or pallets namely canoes kayaks rafts are controlled by the generation of a higher propelling force to the side of the away from the boat from the direction of the jet skis turn are steered by weight roller thrust movement and the water jet induced vectorization water skis and surfboards are steerable by weight displacement only induced roll.
Aircraft are normally run by the use of fins on the plane bank in a turn - the rudder is used to minimize the negative lace rather than as a means to cause the tower directly airships Missiles and hovercraft are usually driven by the rudder or thrust vectoring jetpacks and flight platforms are controlled by only helicopters vectored thrust are directed by a cyclic control, changing the main rotor thrust vector s, and the anti-torque control, usually supplied by see a tail rotor flight controls of helicopters.
Tunneling are directed by hydraulic tilting of the cutting head of the rail vehicles namely tramway trains are directed by guide tracks curves, including switches and yachts articulated undercarriages land on wheels and buggies kites are oriented in the same the ice yachts cars and bobs are turned to rotate the lead pack out of the direction of travel Snowmobile to guide in the same way by turning the skis before tracked vehicles ie tanks orient increasing strength drive on the opposite side of the rotation direction of the sled horses and dog sleds are oriented by changing the direction of zero traction lawnmowers turn use independent hydraulic drive wheels to turn in place.
German cars to heavy steering, cars, heavy, power steering, power steering systems.