Steering Systems Topics covered in this presentation: Basic Steering Systems Linkage Steering Rack-and-Pinion Steering Power Steering

Basic Steering Systems Two main types of steering: Drop arm Idler arm Track rods Centre link Steering knuckles Steering gear/box Linkage or Conventional type (also known as Parallelogram). Rack-and-pinion type. Linkage type uses a worm gear inside the steering gear/box, this operates the drop arm, then couples to a centre link, idler arm, track rods and the steering knuckles. Track rods Rack-and-pinion Rack-and-pinion type uses track rods to couple the rack to the steering knuckles. Next >

Question 1 What is the linkage type of steering system also known as? A) Complicated type B) Rack-and-pinion type C) Parallelogram type Correct Answer = C D) Idler type

Question 2 Which type of steering system uses a worm gear inside the steering gear/box? A) Linkage type B) Rack-and-pinion type Correct Answer = A

Steering Shafts and Columns Nearly all steering systems use a steering column or shaft to link the driver (steering wheel) to the steering rack or gear/box. Flexible coupling isolates steering wheel from road shocks. Steering wheel Steering rack or gear/box Universal joints allow steering shaft angles to change. Collapsible section Flexible coupling Most steering columns are designed with a collapsible section that helps prevent forces generated in a collision being transferred to the driver. Universal joints Master spline location Bottom of steering column normally has a master spline where it mounts onto the steering rack-and-pinion or steering gear/box. Next >

Question 3 What is the name of the joint that allows the steering shaft angle to change? A) Hinged joint B) Universal joint C) Hanging joint Correct Answer = B D) Flexible joint

Ball Joints Ball joints are common on most steering systems and provide a controllable link to the other steering components. Ball socket Track rod end Adjusting thread Adjusting lock nut Inner track rod Ball joints allow linkage components to swivel freely. Suspension (vertical) and steering (horizontal) movements. Ball joint Inner track rod Boot Shock damper assembly Nearly all ball joints have some form of adjustment. Most steering rack ends have adjustable ball joints and some incorporate shock dampers. Next >

Drop arm (connected to steering gear/box) Linkage Type Steering System Idler arm Drop arm (connected to steering gear/box) Idler arm bracket Steering damper Track rod assembly Track rod assembly Centre link Linkage type steering has many component parts and is normally found on older vehicles. Next >

Question 4 What does the Drop arm of a linkage steering system connect to? A) Idler arm B) Track rod C) Steering column Correct Answer = D D) Steering gear/box

Re-circulating ball type Steering Gear/box Principles Most linkage type steering systems require some form of mechanical advantage, this is provided mainly by the gear ratio in the steering gear/box. Three main types of steering gear/box: Worm Gear Re-circulating Ball Worm and roller (older Vehicles) Worm gear type Re-circulating ball type Most common are “Worm Gear” and “Re-circulating Ball”. Drop arm couples to links. Worm drive on steering shaft. Re-circulating ball mechanism. Small number of teeth needed. Next >

Rack-and-Pinion Type Steering System Rack-and-pinion steering is more precise and compact. Uses less component parts. Steering knuckle Steering column Ball joint Steering rack Track rod Boot More common on modern vehicles. Next >

Question 5 Which of the following is an advantage of a rack-and-pinion steering system over a linkage steering system? A) It can be made larger B) It contains fewer parts C) It is more common Correct Answer = B D) It can be used on cars

Rack-and-Pinion Steering Principle Pinion gear is turned by steering shaft. Pinion meshes with rack to move it sideways. Thrust spring holds rack against pinion to prevent backlash. Pinion shaft is normally shimmed to minimize end float (up or down movement) also reducing backlash. Next >

Question 6 A rack-and-pinion gear, as used in a steering system, converts rotary motion to linear motion. Is this true or false? Answer True False Correct Answer = T

Basic Power Steering Systems Power steering uses hydraulic fluid pressure to assist steering movement. Three main types: Rack-and-pinion Integral piston External cylinder All systems require a reservoir, pump, hoses, control valve, pressure relief valve and a hydraulic cylinder. Next >

Question 7 What substance is used to assist steering in a power steering system? A) Compressed air B) A vacuum C) Hydraulic fluid Correct Answer = C D) Distilled water

Power Rack-and-Pinion Steering Power cylinder acts directly within the steering racks main body. Fluid reservoir can be located on top of belt- driven hydraulic pump. Control valve within steering rack body connected to top of pinion shaft. Steering gear mounted to cross-member or frame. Fluid fed to power cylinder via valves and hoses. Next >

Control valve (inside pinion housing) Power Rack-and-Pinion Operation Control valve operates with direction of movement of the pinion gear (steering column). Rack Pressure hoses Power cylinder Seals Steering column Control valve (inside pinion housing) Control valve directs fluid flow to the correct side of the power cylinder piston. Piston Piston moves and assists steering rack movement. Next >

Integral-Piston Power Steering System Hydraulic pump belt-driven from engine. Control valve and piston in steering box housing. Piston inside the steering box assists Drop arm movement. Idler arm guides lateral movement. Track rods link to steering knuckles. Next >

Control valve (part of the gear housing) Integral Power Steering Gear Operation Some belt-driven pumps have integral reservoir. Reservoir Pump Control valve (part of the gear housing) Steering wheel stationary - pressure to control valve returned to the reservoir. Steering wheel to right - control valve moves and feeds pressure to the correct side of the piston to give turning assistance. Piston Drop arm Gear housing Steering wheel to left - control valve moves and feeds pressure to the other side of the piston, giving turning assistance in the opposite direction. Next >

Question 8 What does the belt of a hydraulic pump connect to? A) Drop arm B) Engine C) Steering column Correct Answer = B D) Piston

External Cylinder Power Steering Power cylinder attached to frame via a bracket and to centre link. Steering gear couples to Drop arm. Control valve fed from Drop arm. Standard idler link. Pump has reservoir on top. Next >

Power Steering Pumps Many different types of pumps can be used, the most common is the vane type. Cap and fluid level dipstick Power steering vane pump component parts. End plate seal Belt Bearing Pulley Pump body and centre shaft Vanes Vane body Vane housing Supply and return hoses Next >

Vane-Type Steering Pump Operation Vanes throw out into cammed cylinder. Vanes Cavity expands near inlets forming vacuum. Fluid compresses near outlets forcing fluid out. Low pressure in inlet pipes. High pressure in outlet pipes. Next >