STEERING COLUMN AND SHAFT

2016 – MX-5 – Steering

The steering input force, generated when the driver operates the steering wheel, is transmitted to the steering gear.

The steering column and shaft consists of the steering column and the intermediate shaft.
As a result of impact absorbing mechanisms on the steering column and intermediate shaft, when a collision occurs, the steering shaft effectively absorbs the impact energy that would be transmitted to the driver, thereby reducing injury.
A steering column equipped with a tilt mechanism has been adopted.

Energy absorbing system

At the moment of a collision, if impact energy (first stage impact) from the vehicle front is applied due to the rearward movement of the steering gear box, the intermediate shaft contracts. The impact will not be applied to the driver because the amount of the rearward movement of the steering gear box is smaller than the amount of the contraction of the intermediate shaft. (Section X in the figure)
The impact applied to the driver when the driver’s body hits the steering wheel (second stage impact) is transmitted to the upper shaft, outer column, and the fixing bracket. As a result, the fixing bracket breaks away from the dashboard member, and the upper shaft and outer column moves forward. At this time, the impact absorption plate (one part secured to dashboard member, another part to fixing bracket) breaks along area A and the impact to the driver is absorbed. (Section Y in the figure)

Tilt mechanism

The steering wheel can be moved in the up/down direction by pressing the tilt lever towards the front of the vehicle and releasing the lock of the tilt system.
The tilt mechanism has a 42 mm {1.7 in} adjustable range in the up/down direction, and can be adjusted freely (non-step) within the ranges.