NSK
The device can prevent overloading in vans, light trucks, and other vehicles.
The hydraulic device has a flexible diaphragm (a thin material layer that flexes under pressure) that deforms under load, thereby increasing pressure in the fluid chamber. Load is calculated based on the increase in pressure. The hydraulic fluid is essentially non-compressible (high bulk modulus), which enables a design that operates with minimal diaphragm flex.
A double layer seal to prevent fluid leakage is an integral part of the design. In the highly unlikely event of a hydraulic fluid leak, the suspension spring will only extend a tiny amount to close a gap above the piston, resulting in no adverse effects on the suspension system. The load detection device also features an ultra-thin (25 mm), compact design to avoid significantly shortening the suspension stroke.