What Is a Hydraulic Damper?
A hydraulic damper is a device that absorbs vibration and shock through hydraulic pressure. They are used in vehicles and building structures. They are also sometimes called shock absorbers.
Hydraulic dampers allow for flexible adjustment through the control of hydraulic pressure. By varying the oil flow and pressure in the damper, the control characteristics of vibration and shock can be adjusted.
This allows them to respond to a wide variety of situations and requirements. They are generally durable and provide stable performance over a long period. If properly maintained, they have a long service life.
However, each hydraulic damper product has certain usage ranges and limitations. Care should be taken not to exceed the recommended maximum load or pressure. Excessive loading or use under conditions outside the operating range may cause damper failure or reduced effectiveness.
Uses for Hydraulic Dampers
Hydraulic dampers are widely used in a variety of applications. The following are examples of typical applications:
1. Automobiles
Hydraulic dampers are often used in automobile suspensions. They absorb vibrations and shocks from the vehicle body and improve ride comfort. They can be adjusted to the appropriate damping force in response to various road conditions.
2. Vibration Control Devices
They are often used as vibration control devices for building structures and bridges. They absorb external forces such as earthquake and wind, and serves to control vibration of the structure and ensure its stability. This can improve the seismic resistance and safety of structures.
3. Industrial Machinery and Equipment
They are often used to control vibration and shock in industrial machinery and equipment. They are utilized to control the vibration of conveyor belts and to absorb shocks during large machine operations.
Principle of Hydraulic Dampers
The basic principle of hydraulic dampers is based on the turbulent resistance of fluid. Turbulent resistance is the principle that resistance increases in proportion to fluid velocity.
A hydraulic damper consists of a cylinder, a piston, and hydraulic oil. In most cases, the cylinder is filled with hydraulic oil. When pressure is applied to the piston rod, the rod pushes the hydraulic oil filled in the cylinder.
There is a small space between the cylinder and the piston, and the hydraulic oil flows into this void. This flow of hydraulic oil creates resistance and dampens shocks. Vibration and shock are often absorbed as thermal energy of the hydraulic fluid.
By adjusting the width and number of voids, the cushioning characteristics of hydraulic dampers can be changed to suit the object. When incorporated into seismic isolation and vibration control mechanisms of buildings, quantities are required to ensure adequate functionality.
Types of Hydraulic Dampers
There are two types of hydraulic dampers: monotube and twin-tube.
1. Monotube
A monotube damper is a hydraulic damper that consists of a single inner and outer tube. The inner tube functions as a damper cylinder with a piston inside. The outer tube houses the piston rod and covers the damper cylinder.
The piston inside the inner cylinder can control the flow of oil, enabling a higher level of damping characteristics. This improves responsiveness and control accuracy. In addition, the outer cylinder effectively dissipates heat from the oil, making it easier for damper performance to remain stable over long periods of operation.
Due to its high control performance and heat dissipation capability, it is often used in suspensions for sports cars and high-performance vehicles.
2. Twin-Tube
A twin-tube damper is a hydraulic damper consisting of two tubes, an inner tube and an outer tube. The inner tube serves as the main damper chamber and has a piston inside. The outer tube functions as a reservoir tube that houses the oil.
Twin-tube dampers are characterized by lower manufacturing costs than mono-tube dampers. They are also relatively lightweight, making it possible to reduce the weight of the vehicle. Because of these features, these hydraulic dampers are widely used in mass-market and general-purpose vehicles.