What is the use of rubber bushing in automobile rubber mount?

What is the use of rubber bushing in automobile rubber mount?

In fact, most rubber parts on automobiles are closely related to the original intention of "cushioning and vibration isolation". For example, the invention of tyres - tyres were first used on bicycles. The earliest bicycles had no tires. At that time, the road conditions were very poor. They were either unpaved or flagstone roads on which bicycles ran. Cyclists are very uncomfortable, which also limits the speed of riding. It is said that in a folk bicycle race, a contestant saw a rubber hose for irrigation in his garden before the race and tied it to the bicycle wheel on a whim. Although this pair of "home-made" tires is not as good as the later pneumatic tires, it still works, helping the contestants to win the championship at one stroke and making everyone follow suit.

The bushing on the rubber mounting frame and even the invention of the powertrain suspension are all based on the same starting point, just to make people more comfortable.

For rubber mounting frame, the vibration source is the road surface. The undulation of the road surface acts on the wheels and is transmitted to the body through the suspension. In suspension, there are two ways to transmit vibration: one is spring and shock absorber, and the other is control arm of suspension. In terms of vibration isolation, no matter how good the springs and shock absorbers are, they can't prevent vibration from going the other way, so there are rubber bushings and the like.

With the increase of bushings, rubber mounts also bring derivative products. It not only absorbs and isolates vibration through deformation when the road surface is uneven, but also deforms when the dynamic changes such as steering, braking and acceleration occur. The deformation at this time has two effects: one is the deformation characteristics of the suspension frame, namely the "C" characteristic in the K&C characteristics; The other is to change the frequency characteristics of the suspension or its responsiveness to driving operations.

Although these two derivative effects are not the original intention of casing, they are gradually used by engineers. For example, when our car is driving on the deceleration belt, the deformation of the bushing can make the wheels slightly backward, and the impact force will be smaller.

So why don't many cars have bushings? What if there is no bushing?

First of all, people will feel uncomfortable when shaking. Large road undulations can still be handled by springs and shock absorbers, but the tingling vibration that makes people feel numb is "honestly" transmitted to the body.

Secondly, it will be very noisy. There will be "crunching", "crackling" and other noises, and even the interior will become loose under long-term vibration.

Again, the life of the suspension will be much shorter. The car with rubber bushing can withstand the durability of 100,000 km, but the joint bearing (commonly known as "fish eye" or "ball joint") cannot. No racing car needs to be replaced every 100000 km.

Eventually, cars will become difficult to drive. Of course, the "hard driving" here is aimed at ordinary consumers, and for racing drivers, they can't wait. On a car without bushings, if you turn the steering wheel a little faster, you will feel that you are being kicked sideways, and the car's reaction will become more direct and faster. For ordinary civilians, we do not want cars to react so quickly, but to slow down a bit to make people feel more comfortable and relaxed.