What Does a Power Steering Gear Consist Of?
4 Answers
Power steering gear consists of components such as the steering wheel, steering shaft, and steering column. The working principle of the power steering gear is as follows: 1. In the neutral position, the oil from the pump returns to the oil tank through the internal mechanism of the steering gear. 2. During power steering, the oil from the pump enters the cycloidal gear pair through the servo valve, pushing the rotor to follow the rotation of the steering wheel. Depending on the angle, direction, and quantity of the steering wheel's rotation, hydraulic oil is directed into the left or right chamber of the cylinder, thereby pushing the guide wheel to achieve power steering. The function of the power steering gear is to amplify the force transmitted from the steering wheel to the steering linkage and to change the direction of force transmission. The steering gear, also known as the steering mechanism, is a set of gear mechanisms that convert rotational motion into linear motion, and it also serves as a reduction gear in the steering system.
Last time I repaired my old Bora, this was taken apart. Simply put, the power steering system consists of three main parts: the steering column connects the steering wheel like a spine, the middle is a gear set with a hydraulic valve responsible for transmitting steering force, and at the bottom lies the rack rod with an assist piston. Focus on the power assist system—traditional cars rely on a hydraulic pump driven by the engine belt to output pressurized oil, which pushes the piston through metal oil pipes. Nowadays, many new cars use an EPS system where the motor directly drives the gear, and my electric car even eliminates the hydraulic oil reservoir. Remember to check the power steering fluid level; if it turns black, it needs replacement. Leaking oil pipes can cause the steering wheel to suddenly become heavy, which is very dangerous.
During auto repair training, the instructor explained that from a mechanical structure perspective, there is a steering input shaft connected to the steering wheel, which converts direction through a worm-and-sector or rack-and-pinion mechanism. The core lies in the power assist unit: hydraulic systems require an oil pump, reservoir, control valve, and power cylinder; electronic systems replace these with a torque sensor, control computer, and assist motor. From my experience, when the steering wheel feels heavy, first listen for any abnormal buzzing sounds—that might indicate the hydraulic pump is failing. For older vehicles, pay attention to wear in the steering linkage ball joints, which can cause clunking noises when turning. Nowadays, high-end cars even eliminate mechanical connections with steer-by-wire systems, controlling wheels purely through electrical signals.
I've researched this when modifying race cars. The basic components are the steering column + reduction gear set + rack mechanism, with the focus on the power assist module. The hydraulic power steering system requires the engine to drive a vane pump to generate 8-12MPa oil pressure, which is distributed through a rotary valve. The electronic power steering system is more sophisticated: the torque sensor under the steering wheel acts like human nerves, detecting even 0.1-degree rotations, and the computer instantly calculates and commands the brushless motor to output assistance. Remember to readjust the steering angle sensor when modifying coilover suspensions, otherwise the assist curve will go haywire.
