Differential | How does it work?

00:04:47
https://www.youtube.com/watch?v=nC6fsNXdcMQ

Summary

TLDRThe video explains how differentials operate in four-wheel vehicles, allowing wheels to turn at different speeds while receiving power from the engine. It illustrates the role of differential components like the ring gear, pinion gear, and spider gears in facilitating this function. By enabling wheels to rotate at various speeds, differentials prevent wheel slippage during turns. Additional functions include speed reduction for torque multiplication and altering power flow direction. Standard differentials face a challenge in uneven traction scenarios. Limited slip differentials, which address these issues, will be discussed in future content.

Takeaways

  • 🚗 Differentials let wheels spin at different rpms, crucial for turns.
  • ⚙️ Power flows from the engine to the wheels via a pinion and ring gear.
  • 🔀 Spider gears aid in adjusting wheel speed differences.
  • 🛞 During straight motion, the gear assembly acts as a solid unit.
  • 🌀 Turning involves spider gears spinning on their axis for speed adjustment.
  • ⚠️ Standard differentials struggle with uneven traction, sending power to the slippery side.
  • 📈 Differentials also reduce speed for torque increase and redirect power flow.
  • 🔄 Directional change of power flow occurs by 90 degrees in the differential.
  • 🛠️ Heavy-load vehicles incorporate more spider gears for durability.
  • 💡 Future content will explore limited slip differentials to solve current drawbacks.

Timeline

  • 00:00:00 - 00:04:47

    The differential in vehicles is crucial for allowing wheels to rotate at different speeds, especially when turning, ensuring power is effectively distributed from the engine to both wheels. It achieves this through a series of gears, specifically the ring and pinion gears connected to the spider and side gears. When a vehicle moves straight, these gears spin uniformly; however, during a turn, the spider gear adds a second rotation on its axis to adjust for the differing wheel speeds. This mechanism is essential for smooth turns. Additionally, differentials reduce speed and increase torque, and alter the power direction by 90 degrees. However, standard differentials struggle on mixed traction surfaces, leading to the development of limited slip differentials.

Mind Map

Video Q&A

  • What is the main function of a differential in vehicles?

    The main function of a differential is to allow wheels to turn at different rpms while receiving power from the engine.

  • How does a differential work?

    A differential uses a ring gear and a spider gear to allow wheels to rotate at different speeds by transferring power from the engine to the wheels.

  • What problem arises with a standard differential on slippery surfaces?

    A standard differential sends most of the power to the wheel with less traction, which can prevent the vehicle from moving effectively.

  • What happens to the spider gear when a vehicle moves straight?

    The spider gear rotates with the ring gear but does not rotate on its own axis, pushing both side gears to turn at the same speed.

  • How does a differential assist when a vehicle is turning?

    The spider gear spins on its axis to accommodate the differing speeds of the wheels, allowing left and right wheels to rotate at different rpms.

  • What are the additional functions of a differential apart from allowing different wheel speeds?

    A differential also reduces speed at the pinion ring gear assembly for torque multiplication and changes the direction of power flow by 90 degrees.

  • What is an open differential and its drawback?

    An open or standard differential allows wheels to rotate at different rpms but may send most power to the wheel with less traction, hindering movement.

  • What is the purpose of adding more spider gears in a vehicle?

    More spider gears are added to carry heavier loads in vehicles.

  • What will be covered in a future video according to the current video?

    A future video will cover limited slip differentials which address the drawbacks of standard differentials.

  • How can viewers support the channel?

    Viewers can become a Learn Engineering member by clicking the support button.

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Subtitles
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  • 00:00:00
    the differential is an integral part of
  • 00:00:02
    all four wheelers
  • 00:00:04
    wheels receive power from the engine via
  • 00:00:06
    a drive shaft
  • 00:00:09
    and the main function of the
  • 00:00:10
    differential is to allow these wheels to
  • 00:00:12
    turn at different rpms while receiving
  • 00:00:14
    power from the engine
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    consider these wheels which are
  • 00:00:20
    negotiating a turn
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    clearly the left wheel has to travel
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    more distance than the right wheel
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    which means that the left wheel has to
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    rotate at a higher speed
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    if these wheels were connected using a
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    solid shaft as shown
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    the wheels would have to slip to
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    accomplish the turn
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    this is exactly where a differential
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    comes in
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    the ingenious mechanism in a
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    differential allows left and right
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    wheels to turn at different rpms while
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    transferring power to both wheels
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    step by step we will learn how a
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    differential achieves this feat using
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    its simplest configuration
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    power from the engine is transferred to
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    the ring gear
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    through a pinion gear
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    the ring gear is connected to a spider
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    gear which is at the heart of the
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    differential
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    the spider gear is free to rotate in two
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    different ways
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    one along the ring gear
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    and two on its own axis
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    the spider gear is meshed with two side
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    gears
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    so power from the engine flows from the
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    pinion to the left and right wheels as
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    shown
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    now let's consider different cases
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    when the vehicle moves straight
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    the spider gear rotates along with the
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    ring gear
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    but it does not rotate on its own axis
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    the spider gear will push and make both
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    side gears turn at the same speed
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    when the vehicle is moving straight the
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    spider side gear assembly will move as a
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    single solid unit
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    consider the case when the vehicle is
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    taking a right turn
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    the spider gear plays a pivotal role
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    here
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    along with the rotation of the ring gear
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    the spider gear spins on its own axis
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    fact the spider gear is forced to do
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    this second spin to meet the demands of
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    the right and left wheels differing
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    speeds
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    so the spider gear is having a combined
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    rotation
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    the effect of combined rotation on the
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    side gear is interesting
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    when properly meshed the side gear has
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    to have the same peripheral velocity as
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    the spider gear
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    when the spider gear is spinning and
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    rotating the peripheral velocity at the
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    left side of the spider gear is the sum
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    of spinning and rotational velocity
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    however on the right side it is the
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    difference between the two
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    the left side gear will have higher
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    speed compared to the right side gear
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    which is how the differential manages to
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    turn left and right wheels at different
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    speeds
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    taking a left turn the spider gear will
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    spin in the opposite direction
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    in order to carry load one more spider
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    gear is usually added four spider gear
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    arrangements are used for heavy load
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    vehicles
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    apart from allowing wheels to rotate at
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    different rpms the differential has two
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    more functions
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    the first of these alternate functions
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    is speed reduction at the pinion ring
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    gear assembly which will result in
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    torque multiplication
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    the other function is to turn the power
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    flow direction by 90 degrees
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    the differential we have gone through so
  • 00:04:04
    far is known as an open or standard
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    differential
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    it is capable of turning wheels at
  • 00:04:11
    different rpms
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    but it has one major drawback
  • 00:04:15
    consider a situation where one wheel of
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    a vehicle is on a surface with good
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    traction and another wheel is on a
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    slippery track
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    in this case a standard differential
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    will send the majority of the power to
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    the slippery wheel
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    so the vehicle won't be able to move
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    to overcome this problem limited slip
  • 00:04:36
    differentials were introduced
  • 00:04:38
    we will learn more about those in a
  • 00:04:39
    separate video
  • 00:04:41
    please be a learn engineering member by
  • 00:04:43
    clicking the support button we'll see
  • 00:04:44
    you soon with a new video
Tags
  • differential
  • four-wheelers
  • mechanics
  • drive shaft
  • spider gear
  • ring gear
  • power transmission
  • torque multiplication
  • traction