What is the working principle of a power steering system?
2 Answers
The working principle of a power steering system is: when the car is driving straight, the steering control valve connects the working fluid pumped by the steering oil pump to the oil tank, and the steering oil pump is in an unloading state. When the car needs to turn right, the steering control valve connects the working fluid pumped by the steering oil pump to the R chamber and connects the L chamber to the oil tank, causing the left and right wheels to deflect to the right through the transmission structure to achieve a right turn. The function of the steering gear is to amplify the torque applied by the driver to the steering wheel and reduce the speed, then transmit it to the steering linkage. Since the steering gear is a mechanism with a large transmission ratio, its transmission efficiency is generally low. The ratio of the output power to the input power of the steering gear is called the transmission efficiency of the steering gear. The transmission efficiency obtained when the power is input from the steering column and output from the steering rocker arm is called the positive efficiency, while the efficiency obtained when the transmission direction is opposite is called the reverse efficiency.
The working principle of power steering is essentially to help reduce the effort required when we turn the steering wheel. Imagine driving an old-fashioned car where the steering wheel feels as heavy as a rock, requiring tremendous force to turn, especially at low speeds or when parking. The power steering system's role is to quietly add an extra force to assist you whenever you turn the wheel. The most common type is hydraulic power steering, which uses the engine to drive a pump that generates hydraulic pressure; this pressure is then transmitted to the steering mechanism, making the steering feel light. Another increasingly popular type is electric power steering, which uses a small motor to sense the force applied to the steering wheel and automatically provides assistance, making the operation more fuel-efficient and smoother. I've compared driving new and old cars—without power steering, your arms ache after a while, but with it, driving becomes a pleasure, especially when turning effortlessly. Overall, this mechanism enhances driving safety and comfort, and it can adjust the steering effort based on speed—for example, the steering feels more stable at high speeds to prevent the car from being overly sensitive and unstable.
