Guessing gearbox arrangements?

  • Thread starter akueddy
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In summary, the electric car jack gearbox has 15x2x4cm dimensions, and can produce 25*0.4=10Nm of torque. The gear arrangements can increase the motor torque 25x, to a maximum of 10Nm.
  • #1
Hi guys,

I am trying to do an analysis of an electric carjack, i know the load, i know the torque require at the end of the jack(ive calculated it to be 5Nm). i know the typical electric car jack uses 12V 10A pmdc motor (about 3500rpm no load speed and stall torque 0.4Nm).
I know that to maximize the output torque of the motor i need a gearbox that'll give out the optimum mechanical advantage. I don't have any clue how the design of an eletric car jack gearbox which is on the market, but i know the dimensions of it,15x2x4cm, below is the link of my design base on the dimensions.
units are in cm and all the gears are fix to the shaft/motor. [Broken]

Anyway, the gear arrangements will increase the motor torque 25times(assume super efficient).and so this will give out 25*0.4=10Nm. Well its larger than the required torque,so it'll work but wait..thats assuming if the gears are 100% efficient, and at stall torque..

So my question is can anybody like suggest any other gear arrangements which gives out more than mine or speculate what are the gear arrangements on the electric car jack on the market right now?

thank you
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  • #2
I don't think you could cut teeth strong enough in a pinion with a diameter of 1 cm.

Have you thought about worm gears?

These gears also have the advantage that you don't need a brake, as they are irreversible transmissions, so you can switch off the motor and the car won't come down. And with a bevel gear you can keep the motor in the position you've drawn.

The efficiency of spur gears is about 90%, but bevel, and worm gears have lower efficiencies
  • #3
I agree that a worm & roller set is the proper way to go. The mechanical advantage is awesome, and there is the bonus of irreversibility that sunday pointed out.
For an even higher ratio, epicyclic trains are available or buildable that can give you over 1,000:1 gearing.
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  • #4
Wait. I realized there is a image of the jack in the pic you posted, and that type of "scissors" jack is irreversible as is. So you don't need an additional worm gear, and, yes, your gear arrangement could do.

Which level of detail you need in the solution? If this is for some courses of machine design you'll have to produce the # of teeth in every gearwheel, and in advanced courses, the modulus of the teeth.

Have you got more information about the gearbox? e.g. # of intermediate shafts, distances between shaft centers, etc.
  • #5
I never saw that picture the first time around either. The scissors jack is indeed based upon a lead-screw. It was my impression that you were going to build the whole thing from scratch. If you have that final-stage preassembled as in the picture, then your design is fine.

1. What is a gearbox arrangement?

A gearbox arrangement is a system of gears and shafts that work together to transfer power from a motor or engine to the wheels or other mechanical devices. It is used to change the speed and torque of the input power to match the specific needs of the machine or vehicle.

2. How do you determine the correct gearbox arrangement for a specific application?

The correct gearbox arrangement is determined by considering factors such as the required speed and torque, the size and weight of the machinery, and the type of power source. A thorough analysis of these factors can help determine the most efficient and effective gearbox arrangement.

3. What are some common types of gearbox arrangements?

Some common types of gearbox arrangements include spur gear, helical gear, bevel gear, worm gear, and planetary gear. Each type has its own advantages and is suitable for different applications.

4. How do you ensure the efficiency and durability of a gearbox arrangement?

To ensure the efficiency and durability of a gearbox arrangement, it is important to use high-quality materials, properly lubricate the gears, and regularly maintain and inspect the gearbox. It is also crucial to choose the right type of gearbox arrangement for the specific application.

5. Can a gearbox arrangement be customized for a specific application?

Yes, gearbox arrangements can be customized to meet the specific needs and requirements of a particular application. This can involve using different types of gears, changing the gear ratios, or designing a new arrangement altogether.

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