Effect of thrust force on torque?

In summary: VERTICAL-MOTOR-USEVertical motors are commonly used in applications where the shaft is subjected to a large axial load, such as in pump applications. The use of a thrust bearing in these motors reduces the wear and tear on the motor and bearings.In summary, vertical motors have a thrust bearing and the use of a thrust bearing reduces the wear and tear on the motor and bearings.
  • #1
PCarson85
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1
If I have a motor that is turning a shaft with only a small torque required but the shaft is also being forced into the motor, axially at a large force, what is the effect on the motor here?

If Faxial is large, does this effect T and how does this effect the motor?

Scan - 2020-04-20 10_00_16.jpeg
 
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  • #2
Depending on the bearings, it will wear out pretty soon ! :wink:
 
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  • #3
PCarson85 said:
only a small torque required but the shaft is also being forced into the motor, axially at a large force, what is the effect on the motor here?
If there is a large axial force, you need a thrust bearing to accommodate that force. I don't think many motors include a thrust bearing (I could be wrong), but if you use a motor with a "double shaft", you can put the thrust bearing on the end of the shaft that protrudes out the back of the motor...

https://ae01.alicdn.com/kf/H800cb6f513b9434c94ca5c1d24e0ee0et.jpg

1587396663271.png
 
  • #4
BTW, with a little Google searching, it looks like motors with thrust bearings are used in the vertical orientation (where you would expect more axial shaft loading). Here is a good starting point:

https://www.efficientplantmag.com/2018/04/understand-vertical-motor-bearings/

Vertical motors differ from horizontal units in various ways, including their oil-leak risks.

By Jim Bryan, Electrical Apparatus Service Association (EASA)

Bearing construction is a key difference between vertical motors and horizontal motors that are mounted vertically. Vertical motors typically drive pumps using thrust bearings. Horizontal motors rarely have those types of bearings. Understanding relevant construction and configuration factors is crucial when confronting lubrication-related issues that can be associated with vertical-motor bearings.

VERTICAL-MOTOR-BEARING CONSTRUCTION
Vertical motors commonly have a thrust bearing and a guide bearing. The thrust bearing is usually at the top of the motor and may consist of one or more angular contact bearings, a spherical roller bearing, or a hydrodynamic plate bearing. The force and direction (upward, downward, or balanced) of the applied axial load dictate the type and number of thrust bearings needed to obtain optimum performance and service life.
 
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  • #5
The air gap torque is fixed by the magnetic circuit and is not affected by Faxial. Faxial is going to increase the friction in the thrust bearing and this in turn will reduce the available output torque of the motor.
 
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Related to Effect of thrust force on torque?

1. How does thrust force affect torque?

Thrust force and torque are directly related, meaning that an increase in thrust force will result in an increase in torque. This is because thrust force is the force that acts perpendicular to the axis of rotation, causing an object to rotate, and torque is the measure of the force that causes an object to rotate.

2. Can a change in thrust force change the direction of torque?

Yes, a change in thrust force can change the direction of torque. If the thrust force is applied in the opposite direction of the current rotation, the torque will also change direction. This is because torque is a vector quantity and its direction is dependent on the direction of the applied force.

3. How does the distance between the thrust force and the pivot point affect torque?

The distance between the thrust force and the pivot point, also known as the lever arm, has a direct effect on torque. The longer the lever arm, the greater the torque will be. This is because the longer lever arm allows for a greater moment arm, resulting in a larger torque.

4. What is the formula for calculating torque with thrust force?

The formula for calculating torque with thrust force is T = F x r, where T is the torque, F is the thrust force, and r is the distance between the thrust force and the pivot point (lever arm). This formula is based on the principle that torque is equal to the product of force and distance.

5. How does the direction of thrust force affect torque?

The direction of thrust force has a significant impact on the direction of torque. When the thrust force is applied in the same direction as the current rotation, it will increase the magnitude of the torque. However, if the thrust force is applied in the opposite direction, it will decrease the magnitude of the torque and can even cause the object to rotate in the opposite direction.

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