Auto Steering Rack Guide

According to different structures and working principles, automobile steering gears can indeed be classified into three main types: rack and pinion steering gear, worm crank pin steering gear and recirculating ball steering gear.

Rack and Pinion Steering Gear

This is the most common type of steering gear, its basic structure is a pair of intermeshing pinions and racks. When the steering wheel is turned, the steering shaft drives the gear to rotate, and the gear meshes with the rack, causing the rack to move linearly, which in turn pushes the steering rod to turn the wheels. Rack and pinion steering gears have the advantages of simple and compact structure and high transmission efficiency, and are widely used in various types of automobiles. This kind of steering gear has simple structure, low cost, sensitive steering, small size, and can directly drive the tie rod.

Worm and Roller Steering Gear

The main structure of this steering gear includes worm, crank pin, steering rocker arm shaft and other components. The worm is the driving part and the crank pin is the driven part. When the steering wheel rotates, the worm rotates accordingly, and through the linkage between the crank pin and the steering rocker arm shaft, the rotational motion is converted into the swing of the steering rocker arm, thereby achieving wheel steering. Worm crankpin steering gears are usually used on trucks with large steering forces because they can withstand large steering torques and have high transmission efficiency.

Recirculating Ball Steering Gear

The recirculating ball steering gear uses the rolling of steel balls in the spiral groove to achieve transmission. Its structure mainly includes steering screw, nut, steel ball, rack, tooth fan and other components. When the steering wheel rotates, the steering screw drives the nut to rotate. Through the rolling friction of the steel ball in the spiral groove, the rotational motion is converted into the linear motion of the rack, which then promotes the rotation of the gear sector and realizes the steering of the wheel. Recirculating ball steering gear has the advantages of light operation, low wear and long life, and is widely used in various types of automobiles.

Rack and Pinion Steering Gear

structure:

• Pinion: Apinion is a small cylindrical part with a certain number of teeth on its surface. The pinion is usually mounted on one end of the steering shaft and connected to the steering wheel. When the driver turns the steering wheel, the pinion turn.
• Rack: The rack is a long strip-shaped part with a certain number of teeth on its surface that matches the teeth of the gear. The rack is usually mounted on the vehicle’s suspension system and connected to the wheels through a series of connectors. When the gear rotates, the teeth and the rack mesh with each other, causing the rack to move in the horizontal direction.

working principle:

1. Steering wheel rotation: The driver indicates steering intention by turning the steering wheel.
2. Gear rotation: The driver’s rotation force is transmitted to the gear, causing the gear to start rotating.
3. Gear and rack meshing: The teeth on the gear mesh with the teeth on the rack. As the gear rotates, the rack begins to move in the horizontal direction.
4. Wheel steering: The movement of the rack transmits the steering force to the wheels connected to it, causing the wheels to turn, thereby changing the driving direction of the vehicle.
5. Return to original position: When the driver stops turning the steering wheel, the gear stops rotating, the rack also stops moving, and the wheels return to their original position.

The rack and pinion steering gear has a simple structure, is reliable, and has good controllability and stability, so it is widely used in modern automobiles.

Recirculating Ball Steering Gear

structure:

• Sector Gear: A gear is a disc-shaped part with a certain number of teeth on its edge. The gear is connected to the steering wheel through a connecting rod, and when the driver turns the steering wheel, the gear rotates.
• Pitman Arm: The Pitman Arm is a rod-shaped part connected to the gear. One end of it is connected to the gear through a connecting ball, and the other end is connected to the steering shaft through a connecting rod.
• Recirculating Ball Screw: The ball screw is a spiral part with a thread on its outer surface and a spiral groove inside. The ball screw is fixed on the vehicle chassis and connected to the gear rod.
• Recirculating Ball: The ball is a component that connects the gear and the ball screw. Its function is to roll on the ball screw and transmit the steering force to the gear rod.
• Bearings and guide rails: Used to support and guide the ball screw and balls to ensure smooth movement of the steering system.

working principle:

1. Steering wheel rotation: The driver indicates steering intention by turning the steering wheel.
2. Gear rotation: The driver’s rotation force is transmitted to the gear rod through the gear, causing the gear to start rotating.
3. Ball screw movement: The teeth on the gear mesh with the spiral groove of the ball screw. As the gear rotates, the ball screw begins to move in the spiral direction.
4. Balls transmit power: The balls roll on the spiral groove with the movement of the ball screw and transmit the steering force to the gear rod.
5. Gear rod rotation: The gear rod begins to rotate with the steering force, and the rotation force is transmitted to the steering shaft through the connecting rod.
6. Wheel steering: The movement of the gear rod transmits the steering force to the wheels connected to it, causing the wheels to turn, thereby changing the driving direction of the vehicle.

Although the recirculating ball steering gear is gradually being replaced by rack and pinion steering gears and electric power steering systems in modern cars, it is still used by some commercial vehicles and older models because of its high load-bearing capacity and durability.

Worm and Roller Steering Gear

structure:

• Worm: The worm is a spiral rod-shaped part with a spiral groove on its outer surface. Worms are usually made of steel or other metallic materials.
• Roller: The crank is a cylindrical part with a convex curved surface. The crank mates with the spiral grooves of the worm.
• Pin: The pin is the key part connecting the crank and the wheel. It allows the crank to move in the horizontal direction while being connected to the wheel.
• Connecting rod and steering shaft: The connecting rod connects the crank and steering shaft and is used to transmit steering force.

working principle:

1. Steering wheel rotation: The driver indicates steering intention by turning the steering wheel.
2. Worm rotation: The driver’s rotation force is transmitted to the crank through the worm, causing the worm to start rotating.
3. Crank movement: The spiral groove of the worm causes the crank to move along a spiral trajectory in the vertical direction. The raised curved surface of the crank interacts with the pin, causing the crank to move in a horizontal direction.
4. Rotation of the pin: The movement of the crank causes the pin connected to the crank to start rotating around its own axis.
5. Wheel steering: The rotation of the pin transmits the steering force to the wheel connected to it, causing the wheel to turn, thereby changing the driving direction of the vehicle.

The worm crank pin steering gear has a simple and reliable structure, and is still used in some older models or commercial vehicles. However, it usually requires large turning forces and the steering operation is relatively slow, so it is gradually replaced by more efficient steering systems in modern cars.