Steering Mechanism

[TheAppleMac]

Hi guys,

Does anyone have an idea ( or even picture or maybe a link) which shows how to create a mechanism to steer the front two wheels of a car.

To be more precise: I want to give out "logic 1" (voltage/current not much of an issue as that can be worked around) to activate some sort of motor (possibly a solenoid???) to push the front axle left or right, without actually causing the motor to turn around with the axle. Do I have to connect the wheels to pivots or something? I have tried to open up a couple of RC cars to no avail.

I am not looking for much of a electronics explanation, but a engineering one. However electronics and engineering are very closely related, so I am just wondering if someone has an answer.

Thanks for your time

TheAM

 

[KMoffett]

What kind of car?
This is the steering linkage to a linear actuator I made for a Power Wheels Jeep (the pink one). The blue one is someone else's design.

Ken

 

[TheAppleMac]

Hi ken, thanks for the pictures, they do seem to be what I am looking for. I am making an RC car, controlled by IR. I have already programmed my PICAXE chips, but the only obstacle is that of the steering mechanism. I know it's a big ask, but I can't really understand what is happening in the pictures. Could you pretty please explain the components and their function in the mechanism?
Thanks for your time

TheAM

 

[Joe G]

check my vedio on youtube, https://youtu.be/hMgs-ReFMew , it was also ir-rc and made of junk parts.

 

[KMoffett]

Hi ken, thanks for the pictures, they do seem to be what I am looking for. I am making an RC car, controlled by IR. I have already programmed my PICAXE chips, but the only obstacle is that of the steering mechanism. I know it's a big ask, but I can't really understand what is happening in the pictures. Could you pretty please explain the components and their function in the mechanism?
Thanks for your time

TheAM

The blue Jeep is the easiest. The steering wheel shaft has a dog-leg at the bottom end, that passes through the twisted section of the flat bar, near the right end. The steering wheel shaft and dog-leg forms a crank that pushes the flat bar to the left and right when rotated. The plastic axle-mount arms, connected to the flat bar, pivot and rotate the wheels. With the linear actuator connected to the flat bar, it can push the flat bar left or right, implementing steering.
Mine is more complicated because I wanted to use the full range of a short linear actuator with its internal end-stop switches. That required a compound lever mechanism to match the actuator stroke to the maximum movement of the flat bar.

Ken

 

[4pyros]

Look up ackerman steering.

 

[TheAppleMac]

Ken, thanks for the info. I could really trace what you described to the pictures. Thanks again.

4pyros, thanks also. It seems that ackman steering is the type of mechanism I need - simple and effective enough.

I can now apply both comments to form a decent mechanism, thanks to you both.

 

[Ross Craney]

Acherman steering is a geometric design principle not a type of steering. It is not very important for low weight low speed vehicles

 

[4pyros]

Acherman steering is a geometric design principle not a type of steering. It is not very important for low weight low speed vehicles

Just how do you figure Acherman steering is not a type of steering?
And how do figure its not important for low weight low speed vehicles?
Its on RC cars, its on the Hotwheel cars, and its on small race cars.
If it would fit, I would use it on small robotic cars just to make the batterys last longer.

 

[Ross Craney]

1) Because ackerman steering relies solely on using the Ackerman geometric design principles not any specific hardware. There are no steering components that if used result in it magically being ackerman steering.
2) It is used to accomplish the different turn radius of steered wheels & to minimise turn scrub, something that is not so important on low speed low weight vehicles however by using the ackerman geometry you will minimise tyre wear.
3) I wouldn't describe race cars as low speed low weight
4) It may conserve you battery by resulting in lower turning resistance

 

[KMoffett]

I think there may be a misunderstanding of the difference between Ackerman steering and the linkage in vehicles like the Power Wheels Jeep. In the PW Jeep, and probably many other simple vehicles, the dog-leg arm that is angled rearward from the axle at the pivot point is at a 90° angle to the axle. In the Ackerman linkage, the angle is less than 90° from the axle, causing the difference in pivot-angle of the two tires during steering. https://en.wikipedia.org/wiki/Ackermann_steering_geometry

Ken

 

[4pyros]

"I wouldn't describe race cars as low speed low weight"
Have you ever seen Quarter Midget racing? 250-350Lb cars going 20 to 30 MPH.

 

[4pyros]

Ken; You are right. Looking agin to the photos, the HotWeels use parallel steering.
Look here; It shows both types.
**broken link removed**

 

[Ross Craney]

"I wouldn't describe race cars as low speed low weight"
Have you ever seen Quarter Midget racing? 250-350Lb cars going 20 to 30 MPH.

I wouldn't describe them as race cars but rather fast toys

 

[4pyros]

They are race cars with full suspensions and all the safty gear.

 

[Ross Craney]

That may be the case but what has that got to do with Ackermann steering geometry ?

 

[4pyros]

That may be the case but what has that got to do with Ackermann steering geometry ?

Even these smaller cars use it.

 

[Ross Craney]

[MOD EDIT: Please keep your posts positive and useful.]

There was nothing negative or unhelpful in this post.

 

[duffy]

Thank you for mentioning Ackermann steering, 4pyros. It can be accomplished with a simple shortening of one linkage - relatively easy to implement and understand, gives you more true steering and longer tire life, even on a model car.

 

[4pyros]

Ah Duffy gets it. Small or large everybody benifets from Ackermann steering!!