Gear ratio requirement (RPM --> km/h)

In summary: Then work back through the gearbox to the motor.In summary, the question is asking for the required gear ratio for a vehicle with wheels of diameter 58cm, powered by motors with a maximum speed of 6024 rpm and a maximum speed of 190.2 km/hr. The answer is a unitless value, correct up to two decimals. To solve for the gear ratio, the diameter of the wheel can be used to find the radius. The rpm of the wheel at max velocity can then be calculated, and then worked back through the gearbox to the motor.
  • #1
D.B0004
17
0

Homework Statement


A vehicle having wheels with a diameter of 58cm, is powered by motors that have a maximum speed of 6024 rpm. Each motor is coupled to the wheel using a gear mechanism as shown in figure 2-14. Calculate the required gear ratio if the vehicle's maximum speed is 190.2 km/hr.

Note: Answer is a unitless value, correct upto two decimals.

Homework Equations


No clue. C = 2 * PI * R?

The Attempt at a Solution


I converted 6024 rpm to radians per second hoping I could do the same with hm/hr, but I do not know the radius of the tire? See photo attache for diagram. Thanks for help.
 

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  • #2
D.B0004 said:

Homework Statement


A vehicle having wheels with a diameter of 58cm, is powered by motors that have a maximum speed of 6024 rpm. Each motor is coupled to the wheel using a gear mechanism as shown in figure 2-14. Calculate the required gear ratio if the vehicle's maximum speed is 190.2 km/hr.

Note: Answer is a unitless value, correct upto two decimals.

Homework Equations


No clue. C = 2 * PI * R?

The Attempt at a Solution


I converted 6024 rpm to radians per second hoping I could do the same with hm/hr, but I do not know the radius of the tire? See photo attache for diagram. Thanks for help.
... but you know the diameter of the wheel. How is diameter related to radius?...
 
  • #3
I converted 6024 rpm to radians per second...

I would start "at the other end of the problem". eg Work out the rpm of the wheel at max velocity.
 

Related to Gear ratio requirement (RPM --> km/h)

1. What is gear ratio and why is it important?

Gear ratio is the comparison between the number of teeth on two gears that are meshed together. It determines how much one gear has to rotate in order to make the other gear rotate a certain number of times. It is important because it affects the speed, torque, and power of a vehicle's engine.

2. How do I calculate the gear ratio for my vehicle?

The gear ratio can be calculated by dividing the number of teeth on the driven gear by the number of teeth on the driving gear. For example, if the driven gear has 20 teeth and the driving gear has 10 teeth, the gear ratio would be 2:1.

3. How does gear ratio affect the RPM and speed of a vehicle?

A higher gear ratio means the driven gear will rotate more times than the driving gear, resulting in a higher RPM and faster speed. Conversely, a lower gear ratio will result in a lower RPM and slower speed.

4. What gear ratio is best for achieving a certain speed?

The gear ratio required to achieve a certain speed will depend on various factors such as the vehicle's weight, engine power, and tire size. Generally, a lower gear ratio is better for slower speeds and a higher gear ratio is better for higher speeds.

5. How does changing the gear ratio affect fuel efficiency?

Changing the gear ratio can affect fuel efficiency in different ways. A lower gear ratio can improve fuel efficiency at lower speeds, while a higher gear ratio can improve fuel efficiency at higher speeds. However, changing the gear ratio too drastically can also have a negative impact on fuel efficiency.

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