Hydraulic shock absorber: The unsung hero behind the smooth operation of vehicles

During the vehicle’s journey, we often encounter various uneven road surfaces such as bumps, potholes, and undulations. These conditions can cause vibrations and shocks in the vehicle, not only affecting the comfort of passengers but also potentially damaging the vehicle components. As an important part of the vehicle suspension system, hydraulic shock absorbers play a key role in silently safeguarding the smooth operation of the vehicle.

I. The working principle of hydraulic shock absorber

The working principle of a hydraulic shock absorber is based on the properties of liquids, mainly utilizing the flow of hydraulic oil to achieve damping functions. When a vehicle travels over uneven roads, the wheels move up and down due to the undulations of the road surface, and this movement is transmitted to the hydraulic shock absorber through the suspension system. Inside the shock absorber, there is a piston that divides the internal cavity into two parts, which are filled with hydraulic oil. When the piston moves up and down within the shock absorber cylinder due to the impact force from the wheels, the hydraulic oil flows from one chamber to another through some narrow orifices or throttle valves under the action of the piston. In this process, as the hydraulic oil passes through the orifices, it encounters friction against the walls of the orifice and internal friction between the molecules of the oil, which creates a damping force that opposes the movement of the piston. This damping force can hinder the rapid movement of the piston, converting the kinetic energy generated by the vehicle’s vibrations into thermal energy, thereby dissipating the energy of the vibrations. Ultimately, the thermal energy is released into the surrounding air through the metal shell of the shock absorber, effectively suppressing the vibrations of the vehicle and reducing the repeated bouncing of the springs after absorbing the vibrations, providing a smoother driving experience for the vehicle.。

II. Structural Composition of Hydraulic Shock Absorber

Hydraulic shock absorbers typically consist of several key components, each playing an indispensable role in the damping process.

1. Piston rod and piston: One end of the piston rod is connected to the vehicle’s body or frame, while the other end is connected to the piston. The piston is located inside the cylinder of the shock absorber, and its surface is usually designed with special valve discs or pore structures. When the vehicle vibrates, the piston rod drives the piston up and down within the cylinder, controlling the flow of hydraulic oil. It is one of the core components that achieve the damping function.

2. Cylinder and reservoir: The cylinder is the space for the piston to move and also the main part that contains the hydraulic oil. Some hydraulic shock absorbers are equipped with a reservoir to store additional hydraulic oil to meet the demand for oil volume under different working conditions. The reservoir is connected to the cylinder through specific channels to ensure free flow of hydraulic oil between them.

3. Hydraulic oil: As the working medium of the shock absorber, the characteristics of the hydraulic oil have a significant impact on the damping effect. High-quality hydraulic oil needs to have an appropriate viscosity that ensures good flowability at normal temperatures, allowing the shock absorber to respond promptly to vibrations, and maintains stable performance in high or low-temperature environments, preventing excessive changes in viscosity from affecting the damping effect.

III. Types of Hydraulic Shock Absorbers

Double-tube hydraulic shock absorber: This is the most common type, consisting of an inner tube and an outer tube. The inner tube is primarily responsible for the movement of the piston and the flow of hydraulic oil, while the outer tube serves to protect and store the oil. Double-tube shock absorbers have a relatively simple structure and lower cost, making them widely used in various types of cars, motorcycles, and some industrial equipment. Their advantage is that they can meet the damping requirements of most daily driving conditions to a certain extent, and they are relatively convenient to maintain and replace.

Single-tube hydraulic shock absorber: A single-tube shock absorber has only one working cylinder, which results in a more compact internal structure. It typically uses a combination of high-pressure gas and hydraulic oil; the presence of gas can effectively reduce the foam generated by the hydraulic oil during operation, improving the response speed and stability of the damping force. Single-tube shock absorbers generally have better performance and can adapt to higher-intensity use environments, such as high-performance sports cars, racing cars, and some high-end off-road vehicles. However, their manufacturing costs are higher, and the requirements for production processes and sealing technology are also more stringent.

IV. Application of Hydraulic Shock Absorbers in Different Fields

In the automotive field, hydraulic shock absorbers are an essential component of the suspension system. They not only significantly improve the comfort of vehicle travel and reduce the bumps and vibrations felt by passengers during driving but also have a significant impact on the handling stability and safety of the vehicle. Good damping performance can ensure that tires always maintain good contact with the ground, enhancing the vehicle’s grip and making it more stable and reliable when driving, braking, and steering. Whether it’s daily commuting on city roads or long-distance driving on highways, hydraulic shock absorbers silently protect the smooth operation of the vehicle. In the motorcycle field, the riding characteristics of motorcycles determine that their requirements for the suspension system are even more stringent. Hydraulic shock absorbers also play a key role in motorcycles, helping them to cope with various complex road conditions such as potholes, speed bumps, and curves at high speeds. High-performance hydraulic shock absorbers can enable motorcycles to maintain good handling while providing riders with a comfortable riding experience, reducing fatigue caused by vibration, and improving riding safety. Many motorcycle enthusiasts prefer to upgrade the suspension system when modifying their vehicles to enhance the overall performance of the bike.

V. Factors Affecting the Performance of Hydraulic Shock Absorbers

The quality of hydraulic oil: The viscosity, oxidation resistance, wear resistance, and other performance indicators of hydraulic oil are directly related to the working effect of shock absorbers. Low-quality hydraulic oil may experience changes in viscosity, oxidation deterioration, and generation of impurities during use, leading to unstable damping force of the shock absorber or even failure. Therefore, choosing high-quality hydraulic oil that meets specification requirements is crucial for ensuring the performance of shock absorbers. 2. Design of piston and valve: The structural design of the piston and parameters such as the opening pressure and flow characteristics of the valve have a decisive impact on the magnitude and variation pattern of the shock absorber’s damping force. A reasonable design of the piston and valve can ensure that the shock absorber provides just the right amount of damping force under different operating conditions, effectively absorbing vibration energy without affecting the normal driving performance of the vehicle. For example, when traveling at high speeds, the shock absorber needs to provide a larger damping force to suppress body sway; while passing through bumpy roads at low speeds, it requires a relatively smaller damping force to ensure comfort for passengers.

 

VI. Maintenance and Care of Hydraulic Shock Absorbers

Regularly inspect the appearance: During daily use, it is necessary to regularly check the exterior of the hydraulic shock absorber for any signs of oil leakage. If there are oil stains on the surface of the shock absorber, it may indicate that the seal has been damaged and hydraulic oil is leaking. Once oil leakage is discovered, the shock absorber or seal should be replaced promptly to avoid affecting the damping effect and potentially posing a threat to the vehicle’s driving safety.

2. Check the connecting components: Ensure that the connection parts between the shock absorber and the vehicle’s suspension system are secure and reliable, with no looseness. Regularly check the tightness of the connecting bolts and nuts, and tighten them in a timely manner if they are loose. Loose connecting components can lead to abnormal operation of the shock absorber, produce abnormal noises, and also affect the vehicle’s handling performance.

3. Pay attention to road conditions: Try to avoid long periods of driving under harsh road conditions, such as potholes, raised roads, etc. Excessively harsh road conditions can subject the shock absorber to significant impacts, accelerating its wear and damage. If it is unavoidable to drive under harsh conditions, reduce the speed and pass slowly to minimize damage to the shock absorber.

Hydraulic shock absorbers, as an indispensable and important component in vehicles and numerous devices, may seem unassuming, but they play a crucial role in ensuring smooth operation, enhancing comfort, and safety. Understanding the working principle, structural types, application areas, and maintenance knowledge of hydraulic shock absorbers not only helps us better understand and use vehicles but also enables us to make more informed decisions when it comes to equipment maintenance and selection. With the continuous advancement of technology, the performance of hydraulic shock absorbers is also improving, and in the future, they will continue to provide more reliable support for our travel and industrial production.