About Torque Parts Air Springs Manufacturing
Vulcanization is a chemical process that involves chemically reacting rubber (or elastomeric materials) with temperature to get the desired performance characteristics. In order to improve elasticity, resilience, tensile strength, viscosity, hardness, and weather resistance, the process also involves the creation of cross-links between long rubber molecules.
Furthermore, once the rubber compound is formed by applying the pressure and heat required to vulcanize rubber.
Press vulcanization occurs in presses that provide pressure and heat. A very basic mold for vulcanization is made of two metal plates and features cavities that adapt to create the required completed part's outer shape. In order to vulcanize the rubber, hydraulic or electrical presses force heated plates together that have been heated with electricity steam or hot oil.
Rubber shrinks while keeping its original shape due to vulcanization. The vulcanization process also hardens the rubber, making it less vulnerable to deformation. Rubber hardening boosts its tensile strength as well. It can be summarized the advantages of vulcanization as follows:
- Excellent tenacity.
- It reverts to its previous form.
- Water absorption is low.
- High oxidation and abrasion resistance.
- Excellent electrical insulator.
- Organic solvent resistance.
There are two presses that can be used in vulcanization process. These are called hydraulic and electrical presses. A hydraulic press is a machine press that generates compressive force through a hydraulic cylinder, and an electrical press that generates compressive force with servo motors.
- Electrical presses vulcanizes the rubber faster than other types of presses, thus increasing the efficiency per machine.
- Electrical presses are safer but it needs for pro-active maintenance.
- Electrical presses do not vulcanize the rubber as homogeneously as the steam, negatively effecting the quality and life of the air spring.
- For heavy-duty products, hydraulic presses are better choice for high quality.
In Torque Parts, vulcanization machines has an hydraulic press that supply pressure and heat to form rubber. There are a lot of reasons that why Torque Parts use vulcanization with electrical press. One of the reasons is that these type of presses can stabilize heat and pressure so that the production parts always in high standard process. Also, it has high tonnage capacity.
Rubber is a sticky material as well as chewing gum and it is not a strong material for making products like air springs. Therefore, rubber cannot hold its proper shape if it is not vulcanized. Its properties can be changed by vulcanizing and adapted it to a variety of purposes.
Steam is required for the vulcanizing process. The operation begins with the introduction of a rubber mixture into an autoclave chamber's air spring mold. When this chamber is closed, a burst of highly pressurized steam is fired into the mold.
The rubber expands to fill the mold and then cures as a result of the high temperatures, resulting in a long-lasting completed air spring shape. This is why Torque Parts uses steam boilers, and it is apparent that steams are essential in the heavy duty manufacturing industry.
There are a few different cord fabric types such as Polyamide (PA) / Nylon Cord Fabric, Polyester Cord Fabric, Aramid Cord Fabric etc.
Polyester Cord Fabric is easy to produce, however it is a fiber that does not facilitate air flow. Although it is cheaper than other materials, the fabric adheres to the person’s skin and oil grains stains cannot be removed from it. Moreover, when Aramid Cord Fabric is examined, it is certain that it has a very poor UV resistance and it is not strong enough to resist temperature changes.
Polyamides (PA) or Nylon, on the other hand, is a major high performance engineering thermoplastics due of its good property balance and considered as high performance plastics. Polymaides have excellent thermal and electrical resistance. Moreover, thanks to its crystalline structure, polymides also show excellent chemical resistance.
In Torque Parts, Polyamide (PA) Cord Fabric reinforced with glass is being used to produce, especially for our air spring. When reinforced with glass fibers, polyamide`s stiffness can compete with metals. Also, The advantages of the cord fabric structure used in Torque Parts are given below:
- High temperature strength and stiffness
- Even at low temperatures, the impact strength is high.
- Excellent flow for simple processing
- Excellent abrasion and wear resistance
- Excellent resistance to fuel and oil
- Excellent fatigue resistance
- Excellent electrical insulating qualities
- The utilization is restricted due to the high water absorption and water equilibrium content
- Having higher thermal resistance
- Having better property balance
- Having better chemical and fatigue resistance
- Having better resistance to wear and tear
- Having high mechanical damping characteristics than other fabric types.
Air springs are flexible enough to be used for light or heavy suspension applications and offer a changeable spring rate, adjustable load carrying capacity, ease of height control, and low friction as vehicle`s requirement.
An air spring is a well-built rubber/fabric bellows that contains a compressed air column. The rubber bellows does not provide force or support load on its own. This is done by the column of the air.
A highly engineered elastomeric bellows with specialized metal end closures is an air spring. For higher pressures, many of Torque Parts`s air springs are also available in high strength construction. There are four layers of fabric-reinforced rubber in this case, with an inner liner and an outside cover.
An outer layer is used to support the load when the air spring and suspension when extreme compression contact is made. They are built to endure misalignment, frequent flexing, and inflation pressure. The rubber coating guards against aging, abrasion, and the outside environment. The interior atmosphere and air loss are both prevented by a rubber liner. Corrosion protection, UV and chemical resistance, crack prevention, and puncture resistance are the four main functions of the outer rubber layer.
A second layer is utilized for strengthening material bonding and as a fabric layer spacing layer. Furthermore, it is subject to shear lateral forces.
A first layer is used to support diaphragm forces, and its geometry is maintained indefinitely thanks to the first layer.
An inner layer is employed for pressure distribution, sealing, chemical resistance (from air supply), and gas permeability resistance.In summary,
- Air spring consists of 4 layers which are inner layer, first layer, second layer and outer layer. Inner layer is employed for pressure distribution, first layer is used to support diaphragm forces, second layer is utilized for strengthening material bonding and an outer layer is used to support the load.
- Air spring`s outer layer is the most important part due to it meets the load on it.
- Since the air spring`s outer layer is the outermost layer, it is in direct contact with the atmosphere and the external environment, therefore it is important to have chemical and UV resistance.
- For higher pressure, air spring`s outer layer has to be more durable
Maintaining speed, handling stability, and riding comfort are all crucial considerations for people, primarily drivers. Therefore, as the key part of air suspension or driver’s cab of commercial vehicle, air spring’s developments are taken more seriously. However, the design and theory analyze of the air spring is very difficult and challenging. The application of nonlinear Finite Element Analysis (FEA) method can support to estimate the design of optimal air spring.
Cord Fabric is the main part holding the loads. Therefore, cord fabric angle affects the deformation, internal stress and stiffness of air bag greatly, thus influence the characteristic of the air spring directly. In Torque Parts, for R&D Process the initial pressure and cord fabric Layer Parameters` impact on air spring elastic characteristic, FEA method can be used. That way, the static elastic characteristic of air spring can be simulated under different parameters to determine the cord fabric parameters’ impact.
After optimal design is finalized, plastic deformation and strength can be calculated. As seen below in the Figure 3, blue color in the solid model has minimum value (safe), and on the other hand red color has an about maximum value. According to calculations, the best design of air springs are shown in Torque Parts.
- Performing the analysis while designing the air spring is an important point to obtain a better product.
- For the desired structural analysis, the FEA method can be performed with various computer simulation programs.
- While performing the analysis, it is seen that the cord fabric is the structure that meets the loads applied against the air spring.
- Cord fabric is very important because of its feature. Therefore, the value of cord fabric angles is of great importance in terms of air spring's resistance to stress and stiffness.
In Torque Parts, after designing for each of our products in the same way, we analyze and test. In addition, we continue to work on our products more durable and long life, supported the design with our R&D department.
The air spring is essentially a column of confined gas in a container designed to use the pressure of the gas as the spring's force medium. The gas's compressibility gives the appropriate elasticity for suspension application. Therefore, it can be said that air spring is a kind of vibration isolation element with excellent performance, which uses the elasticity of compressed air to achieve vibration isolation and cushioning.
The effective area of an air spring determines its ability to support a load, which is computed by dividing the load supported by the spring by the gas pressure at any given point. The effective area is determined by the outside diameter of the flexible component and, in the case of rolling lobe changes, the outside diameter of the piston. The design of the spring and its components determines whether the effective area remains constant, increases, or decreases during deflection. The spring rate is determined by the change in effective area and gas pressure when the spring is deflected. The gas pressure varies with the speed and magnitude of deflection; for a unit of deflection, the pressure, and hence the spring rate, different for isothermal, adiabatic, and polytrophic processes as well.In summary,
- Air spring must be resistant to gas pressure due to its design and working principle, and in addition, it must be in an elastic structure to provide suspension.
- Air spring should be in an elastic structure, so it can provide vibration isolation.
- When a load is placed on the air spring, the affected area should increase evenly, decrease or remain constant during deflection.
As a result, air springs must be flexible, have a wide size range, and be able to isolate vibration. Rubber is utilized in Torque Parts for maximum performance, a long life, and a sturdy structure. In addition, Torque Parts's Air Spring has the best isolation degree, a long life cycle, and efficient noise reduction.