125 years after its birth, is the round steering wheel going to be squared?

A while ago, Toyota announced the details of the bZ4X, the first model of the bZ pure electric exclusive series. The new car is positioned as a medium-sized pure electric SUV with a body size similar to that of the RAV4.

I went through the appearance of the new car roughly. It is no different from the concept car exhibited at the Shanghai Auto Show 8 months ago. Although it is worthy of recognition, it is also reasonable.

What really surprises me a little is its steering wheel-it uses a special-shaped steering wheel design.

This reminds me of Formula Cars.

Friends who are interested in motorsports should have noticed that many formula cars use special-shaped steering wheels instead of our usual round shape.


▲The steering wheel of Sauber F1 team Sauber C35, picture from: GPToday

Two reasons: One is the field of vision, and the other is the space.

Take an F1 car as an example, the driver will be firmly fixed in the cockpit in a semi-lying position, with only half of his head exposed outside the cabin, and his vision is extremely restricted. If a round steering wheel is to be added to them at this time, it will greatly increase the difficulty for drivers to obtain track information.

▲It can be seen that the eyes of the driver are not much higher than the steering wheel, the picture comes from: Ferrari team

On the other hand, in the cockpit of "inch of earth and gold", the special-shaped steering wheel can better save leg space. If the steering wheel is still completely round, its lower edge is likely to squeeze into the rider's thigh.

What is the fundamental difference between racing steering wheels and home steering wheels?

The answer is the steering ratio.

What is the steering ratio? The steering ratio of F1 cars is generally between 8:1 and 10:1, which means that when the driver turns the steering wheel 8°-10°, the front wheel will turn 1°. On individual tracks, the maximum steering ratio of F1 cars will even be adjusted to 6:1 (that is, the steering wheel rotates 6° and the front wheel rotates 1°). Such tuning helps the driver to control the car without having to turn the direction drastically.

▲F1 drivers do not need to turn the steering wheel, the picture comes from: Formula 1

Family cars are different.

The race course on urban roads is much more complicated. Considering safety and driving friendliness, the steering wheel of a family car should not be too sensitive. Therefore, the steering ratio of a family car is usually between 12:1 and 20:1. In a corner, the family car needs to take more directions.

After all, it is unrealistic to keep the big brother on the road nervous like a racer. It is unrealistic to control the steering wheel accurately.

▲You who are taking the second subject

How to get the alien steering wheel into the "ordinary people's car"?

If you want big guys to use a special-shaped steering wheel, it will not work to take the circular steering wheel off with a stunned head. If the steering ratio problem is not solved, rashly changing the driving habits of the public may leave a safety hazard.

Toyota is obviously aware of this problem, and their solution is: steer-by-wire.

In the steering system of modern cars, there is a component that connects the steering wheel with the steering mechanism to transmit torque. This mechanically connected steering system is called a mechanical steering system.

▲The steering system of the car, the picture comes from: Mazda

And under the steering wheel of the bZ4X, there is no such steering column. The information transmission and control of the steering are completely realized by electrical signals, which is the wire-controlled steering system. The One Motion Grip technology of Toyota bZ4X realizes the combination of the steer-by-wire system and the special-shaped steering wheel.

There is no physical connection between the steering wheel and the steering mechanism, and the problem of the steering ratio is solved very well. The steering-by-wire can flexibly realize any steering ratio.

▲Steering by wire system, picture from: IndianAuto

In other words, when the vehicle speed is low or the steering angle is large, a small steering ratio is provided, and the driver does not need to twist the steering wheel a few times to achieve a U-turn; The steering ratio ensures the stability and safety of driving.

At this time, there are friends who want to speak:

Isn't this the variable steering ratio? Many homes have it!

Yes, but not all right.

To realize variable steering ratio in mechanical steering system, it is necessary to make a fuss on the rack and pinion mechanism, and realize the change of steering ratio by changing the tooth pitch. But this is after all a system based on a mechanical structure, with a limited range of gear ratio changes and it cannot be flexibly changed.

▲Picture from: Kuaituo Baike

In order to facilitate daily driving, Toyota sets the steering wheel rotation angle to ±150°, which is less than half a circle, which greatly reduces the operating burden of the driver when turning around, warehousing and driving in curves.

In contrast, the functions of "filtering unnecessary vibrations" and "linked driving mode to change the steering feel" of the steer-by-wire are simply for nothing.

What are the advantages of such a steering wheel?

Why did Toyota take so much trouble to bring One Motion Grip technology into the car? Is it just to make the U-turn more convenient?

Remember why formula cars use special-shaped steering wheels?

▲Williams FW43 Williams team, picture from: Motorsport Technology

One is vision, and the other is space.

In order to facilitate the driver to obtain the information on the dashboard at high speed, the dashboard of the F1 car is made very high, reducing the movement of the line of sight from the front road to the dashboard, and maintaining the best sight of the driver.

Toyota's One Motion Grip technology is also true.

For the first time, Toyota adopted a top-mounted instrument panel design on the bZ4X, allowing drivers to easily obtain information on the instrument panel to ensure driving safety.

At this time there is another friend who wants to speak:

Isn't this the high-level dashboard? Many homes have it!

Yes, but not all right.

In my opinion, the high-level instrument panel needs to be "edible" with the special-shaped steering wheel.

▲Picture from: Yiche

Today’s high-level instrument panels on the market have a shortcoming: if the seat or steering wheel is in the wrong position, the instrument panel is easily blocked by the upper edge of the steering wheel; on the other hand, manufacturers cannot design the instrument panel too high, otherwise it will be blocked. As a result, the driver’s line of sight, as a result, the display area of ​​the instrument panel is greatly restricted, entering the embarrassing situation of "no up and no down".

There is no such annoyance on the bZ4X's special-shaped steering wheel. Toyota can make the top-mounted instrument panel larger to accommodate more information.

This is great, right? But the advancement of One Motion Grip does not lie in its extraordinary variable steering ratio, nor does it lie in the field of vision advantages it brings, but is reflected in Toyota's exploration of "space".

It should be noted that the space mentioned here is not the little leg space extruded by the lower edge of the steering wheel, but the "third space" from the future.

▲The movie "Mechanical Enemy"

Remember the telescopic folding steering wheel in "Mechanical Enemy"? Only in manual driving mode, the steering wheel will extend.

Such a design can be found not only in film and television works, but also in concept cars from major manufacturers.

When autonomous driving is truly on the ground and the car becomes our "third space", what we need is to maximize the space inside the car. At that time, will there be room for the steering wheel?

▲Picture from: USA Today

Toyota One Motion Grip laid the foundation for all of this: If the car of the future retains the steering column, how does the steering wheel fold?

With the steer-by-wire system, manufacturers do not need to consider the layout of mechanical connections. The steering torque comes entirely from the algorithm-controlled lower steering gear. It can either rely on the steering wheel for signal input, or it can steer autonomously according to the requirements of the automatic driving system.

Therefore, Toyota's move is the inevitable result of the progress of the times.

The only thing we need to get used to is that Toyota, which has always been stable, has now become the pioneer of the times?

Toyota: "I can't hide it."

The author is a bit busy and writes the introduction later.

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