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EP-4623220-B1 - AIR SPRING WITH VISCOUS DAMPING

EP4623220B1EP 4623220 B1EP4623220 B1EP 4623220B1EP-4623220-B1

Inventors

  • CEP, Nurettin Husnu
  • ALBAYRAK, ISMAIL UTKU
  • ORAL, TOLGA

Dates

Publication Date
20260506
Application Date
20231206

Claims (6)

  1. Air spring with viscous damping used in pneumatic suspension system in vehicles, comprising at least one plate (2) for connecting the suspension with the chassis, at least one piston (4) for connecting the vehicle with the suspension system and at least one bellows (3) for sealingly connecting the plate (2) and the piston (4), at least one piston chamber (V1), at least one bellows chamber (V2) operatively connected to the piston chamber (V1), at least one air flow restrictor element (5) having at least one porous media and positioned on the piston (4) between said bellows chamber (V2) and said piston chamber (V1) for the transmission of fluid between said bellows chamber (V2) and said piston chamber (V1) characterised in that the air flow rate restrictor element (5) having the porosity ratio between 30% and 45% and surface area between 270 mm2 and 405 mm2.
  2. Viscous damping air spring (1) as in claim 1, characterised in that the porosity ratio of the porous air flow restrictor element (5) is between 37% and 40% and the surface area is between 304 mm2 and 328 mm2.
  3. Viscous damping air spring (1) as in claim 1, characterised in that the porous air flow restrictor element (5) is positioned on a piston (4) made of a metal material.
  4. Viscous damping air spring (1) as in claim 1, characterised in that the porous air flow restrictor element (5) is manufactured by sintering.
  5. Viscous damping air spring (1) as in claim 1, characterised in that the porous air flow restriction element (5) is at least two locations on the piston (4).
  6. Viscous damping air spring (1) as in claim 1, characterised in that the porous air flow restriction element (5) is symmetrically arranged on the piston (4).

Description

This invention pertains to achieving a laminar air flow between the chambers and providing the air bellows with the necessary amount of viscous damping force for the pneumatic suspension system, all at a lower cost by eliminating the use of a shock absorber in the pneumatic suspension system. Unlike air springs in the known state of the art, this invention involves having a porous air flow restrictor element between the internal volume of the bellow region and piston region. This not only ensures laminar air flow between the chambers but also imparts the air bellows with the ability to provide the required amount of viscous damping force for the system. In pneumatic suspension systems used in vehicles, air bellows are used to dampen vibrations caused by road conditions. The air springs are usually made of an elastomeric material and designed as a large air cushion. It receives air from an air source controlled by an air compressor or pneumatic system on the suspension system. The air springs can vary this air pressure to adjust the height and ride characteristics of the vehicle. The air spring improves ride comfort by dampening shocks and vibrations at the point where the vehicle's wheels contact the road surface. It also adapts to ground conditions and road conditions by changing the height of the vehicle. Air bellows are generally used in large and heavy commercial vehicles such as commercial trucks and buses. In such vehicles, pneumatic suspension systems are preferred for purposes such as increasing the load carrying capacity or adjusting the height of the vehicle. Another damping part used in the pneumatic suspension system is the shock absorber, shock absorbers are the parts that act as damping in the system and are used to control the vibrations of the suspension system, absorb impacts and improve the handling of the wheels. Shock absorbers are designed to dampen vibrations that occur when the wheels react to unevenness on the road surface. These vibrations can adversely affect the handling of the vehicle and reduce driving comfort. The main task of shock absorbers is to dampen the energy generated by these vibrations, allowing the wheels to grip the road surface more smoothly. The loss of functional properties of the shock absorber element used in the pneumatic suspension systems of heavy commercial vehicles over time creates a major disadvantage for driving safety and comfort. The hydraulic oil in the shock absorber loses its properties over time, the amount of oil decreases due to leakage and other mechanical failures require maintenance on the shock absorbers. In addition, since the shock absorber works at a certain angle on the axle, the direction of the transmitted force is not in a one direction. This situation has negative effects on the loads carried by the vehicle and driver comfort. For these reasons, the service life of the shock absorber decreases and the entire suspension system is negatively affected. American patent document US7644943B2, which is in the known state of the art, said patent document relates to an air bellows arrangement for vehicle suspension systems. In this embodiment, the air bellows and the damper assembly are associated with a porous flow control device located between the air chambers to maintain a laminar flow of air along the flow path of the fluid due to the movement of the air bellows. The porosity air restrictor described in this document is electronically controlled and designed with the ability to be connected to more than one gas chamber. This arrangement is complex and the electronic control unit increases the cost of the product and increases the frequency of replacement and maintenance costs. At the same time, damping can be done depending on an external energy source, which causes the vehicle to consume more energy. American patent document US8540222B2, which is in the state of the art, relates to an air springs mounted on axle or suspension systems used in heavy commercial vehicles. According to the patent document, in order to maximise the functionality of the air springs, an opening is provided between the bellows chamber and the piston chamber for fluid transmission. This design optimises gas and fluid movement in the bellows. The opening mentioned in the patent document has a specific surface area. This surface area is intended to optimise the damping characteristics of the air springs. In other words, the movement of the fluid and the control of the gas pressure are regulated according to these design details. However, as stated in the patent document, this special damping characteristic is not always the same. Especially in high frequency oscillations, the ability of the fluid to maintain its fluidity reduces and turbulent flow is observed between the chambers. This adversely affects the damping characteristics of the air bellows, both reducing its performance and shortening its life. In the American patent document US9744824B2, which is in the