Silicone Bellows Hose

Silicone Bellows Hose

Engineered to dampen engine vibration and accommodate thermal expansion plus assembly offset, this silicone bellow hose is widely used for turbochargers, CAC charge air coolers and air intake systems.

Fluorosilicone lining is available as an option for oil mist, PCV and EGR applications. It conforms to the SAE J20 automotive standard.

Silicone Bellows Hose

Silicone Bellows Hose

Dimensional Accuracy & Consistency

Consistent dimensional control represents the biggest engineering challenge for silicone bellow hoses.

Length dimension
Silicone bellows have a longitudinal shrinkage rate ranging from 6% to 12%. For every part number, we test and obtain its actual shrinkage data before mold revision and mass production. Longitudinal shrinkage is not only related to the raw length, but also coupled with inner diameter. Both factors must be considered simultaneously during mold correction.

Inner diameter
Accurate inner diameter measurement is difficult for this product. These hoses usually come in large bore sizes and are inherently soft, making direct measurement unreliable. Hotop engineers have developed an indirect measurement method paired with mathematical calculation to determine the true inner diameter, which is used to calculate shrinkage and adjust molds. The inner diameter also interacts with the outer support ring and affects the final finished length.

Wall thickness at end beads
The vertical wall thickness on both end flanges is critical for proper assembly. Traditional wrapping processes cannot guarantee stable, consistent wall thickness here. Hotop engineers adopt local compression molding tooling to lock in this key dimension reliably.

silicone bellow hose thickness2

silicone bellow hose thickness1

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Product Description

Hotop silicone bellow hose (also referred to as silicone hump hose) is an aramid multi‑ply reinforced silicone connector with a corrugated bellow profile. The corrugated design permits axial compression, extension and angular deflection to absorb engine movement, thermal shift and assembly misalignment.

• Tight dimensional tolerance for leak‑free clamp installation
• Wide operating temperature range: -50℃ ~ 260℃
• Excellent flexibility and stretch for tight engine‑bay packaging
• Optional fluorosilicone inner layer for oil vapor, PCV and EGR environments
• Custom inner diameter, overall length, convolution count and color available
• SAE J20 compliant 

Mold Design

The vertical end faces of silicone bellows create significant demolding resistance. Hotop engineers implement split mold tooling for this product. While this design moderately reduces cycle efficiency, it ensures clean demolding and eliminates tearing or part damage.

Typical Applications

• Turbocharger and CAC charge air cooler circuits
• Light & heavy‑duty truck intake systems
• Flexible connectors for engine vibration isolation
• Industrial high-temperature air ducting