Shock Absorbers 101


Contrary to the name given to these components, “shock absorbers” don’t actually absorb shocks. The British may actually have the better name for them: Dampers. That’s really a better name term because that exactly what they do, they dampen the oscillations of the vehicles springs.

How they work

After a spring is compressed, it bounces back past its original position and continues to bounce back and forth until its energy is gone. In order to control that bouncing, a dampener is needed. That’s what “shock absorbers” do, they dampen the natural tendency of a spring to bounce back and forth. That’s why the classic quick test of car shock absorber action is to push down hard on one of the four corners of a car and see how long it continues to bounce up and down. If it doesn’t “dampen out” in a few seconds, the shock absorbers likely need replacing.

It started with carriages

The first horse drawn carriages weren’t fitted with shock absorbers.  The result: they bounced around quite a bit. Soon someone started to outfit these carriages with “dampers” to calm down the oscillations. In fact, these early devices were called “friction dampers” because that’s exactly what they did, they dampened the bouncing. As motorized carriages (early automobiles) started to evolve, friction dampeners were used on them too.

Using hydraulics

Frenchman Maurice Houdaille is credited with inventing the first shock absorbers to take advantage of hydraulic fluid. He received his first patent in 1907, and his products eventually became standard equipment on many American automobiles. By the late 1920s, hydraulic shock absorbers were being fitted on most American cars.

The formation of Monroe Corporation

According to Holt Fiat of Hurst, TX, Monroe Corporation was one of the first third-party manufacturers to offer hydraulic shocks to the automotive industry.  Its first hydraulic shock was introduced in 1926 and sales went exponential. In 1951, the company introduced the Monro-Matic shock which established the industry standard for the telescopic shock absorber which we use today.. This design used a tube with a piston that moves up and down through a chamber filled with hydraulic fluid. The movement of the piston draws in or displaces fluid though small internal holes. The size and placement of the pistons and holes determines the damping characteristics of the device.

Active shock absorbers

Today, standard hydraulic shock absorbers are still in wide use because the technology is established.  However, a new type of shock absorber technology is being offered by a few select manufacturers.  This technology is referred to as “Active Shock Absorpbers.”  This is a far more sophisticated technology than standard hydraulic shocks are. How they work is that the rate that the shock absorbers dampen oscillations up and down is controlled by electronically-controlled variable ports in the shocks and the whole system is controlled by a computer module. As the technology becomes more ubiquitous, we will likely see active shock absorption offered on less expensive automobiles.

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