motor coupling to rack & pinion

satanas
Member • Dec 14, 2009

motor coupling to rack & pinion

hi all,
a rack & pinion system in which the pinion, coupled with a motor, is made to move along the rack ( in the vertical plane).. will the weight of the motor (+bracket and the load the pinion is carrying) cause pinion to move down the rack when the motor is stopped???

i will be very grateful if you let me know any problem that might occur from this setup (vertical rack & pinion system)..

can anyone explain to me how this vertical rack and pinion works?
thank u all.
satanas

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Rohan_sK

Member • Dec 14, 2009

Again it would be beter if yu could provide a drawing of your proposed system at least tot the extent that we could decipher how and where are the bracket and motor placed and how much do they protrude outwards from the center of mass of the system.

Anyways, for the information given,

1. You can first check the total weight of the unit ( ie the motor, bracet, platform/stand, pinion, etc.) and make sure that the Rack tooth can withstand the direct and bending stresses at the root.

2. Secondly you can calcualte the unbalanced moment created by the protruding parts of the unit and can design a Ratchet Mechanism to move along the side of the Rack which can balance the moment as well as share the load and also porive the lock by the unidirectional motion it creates.

3. Or else you can just check for some self locking mechanism which self locks in the reverse direction.

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2010mayan

Member • Jan 5, 2010

Hi Satanas,

Let me answer your query subject to following qualification.

> The rack is fixed vertically,
> The pinion along with the gear box & Motor is travelling up & Down the rack.

When the motor is not running , Due to self weight & Gravity ,the pinion along with the gear box & motor will roll down.

To arrest the same , a spring loaded braking system, which can be deactivated by a solenoid plunger ,when the solenoid coil is energised, may be adopted.

THe pinion motor & Solenoid will have to be energised at the same instance to move the load attached to the pinion.

Mayam

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Tkelly

Member • Jan 8, 2010

Ideally, Motor alongwith pinion should be fixed & steady and rack should move up & down. Best solution can be given if you provide some sketch of arrangement.

Tom
<a href="https://www.indovance.com" target="_blank" rel="nofollow noopener noreferrer">CAD Outsourcing Services India | Indovance Inc</a>

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satanas

Member • Feb 14, 2010

hi all..
thx Rohan_sK, 2010mayan and Tkelly for your replies.. sorry i have been away for a long time..

i am curious about this spring loaded braking system.. will find out how it works..

****************************************************************
Tkelly,
Ideally, Motor alongwith pinion should be fixed & steady and rack should move up & down. Best solution can be given if you provide some sketch of arrangement.

well i agree with you but my supervisor wants something new. no-one has ever tried to design and implement something like this.. and its me who is going through all this mess 😔

if i could hide somewhere behind my prototype and support that hub with my hands!! alas!!

cheerzz..

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2010mayan

Member • Feb 14, 2010

Dear Santanas,

Please visit one of the major High rise building construction sites wherein rack & pinion operated Passenger/Goods hoists are in use.All your doubts will be cleared.

Mayan.

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070790vivek

Member • Feb 15, 2010

i think u should go for self locking system which can stop the reverse motionof the rack

if u need more help then tell us what u really want to do.

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satanas

Member • Feb 15, 2010

hi pals,

i did zoom into the spring loaded braking sys but did not find anything that considers solenoids or electromagnets.. instead am getting info on hydraulics and car ABS systems.
what i want is a 'tooth-like device'- normally a rachet found at the base of the hub- that will make contact with a rack teeth and prevent the hub (motor housing) to fall by the action of gravity, when power to my motor is interrupted..i have got the idea of what you guys said.. just need to know if the frictional force between the rachet and the rack tooth will withstand the gravitional force..

weight of hub+motor+load is approximately 25N.. so from this, how do i select that spring loaded braking system?

i know that this braking method is preferred for unidirectional systems, where the teeth are saw-shaped and the rachet have full contact with the vertical edge of the teeth..
now consider it for involute gears..

provides your insights...

Regards,
Satanas

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I.Robinson

Member • May 21, 2010

satanas
hi pals,

i did zoom into the spring loaded braking sys but did not find anything that considers solenoids or electromagnets.. instead am getting info on hydraulics and car ABS systems.
what i want is a 'tooth-like device'- normally a rachet found at the base of the hub- that will make contact with a rack teeth and prevent the hub (motor housing) to fall by the action of gravity, when power to my motor is interrupted..i have got the idea of what you guys said.. just need to know if the frictional force between the rachet and the rack tooth will withstand the gravitional force..

weight of hub+motor+load is approximately 25N.. so from this, how do i select that spring loaded braking system?

i know that this braking method is preferred for unidirectional systems, where the teeth are saw-shaped and the rachet have full contact with the vertical edge of the teeth..
now consider it for involute gears..

provides your insights...

Regards,
Satanas
You should look for a motor with a "naturally on/engaged" break (when power is off the break is engaged) couple this with a gearbox and you should have a system that is fairly non-back-drivable by the load"..(There are back drive specs out there for gearboxes and motors, get them so you know your system is in the allowable range per load mass).

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satanas

Member • May 22, 2010

hi Robinson,

finally i did use a gearmotor!!

anyway, do u guys have an idea what motor i could use to pump paint??

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