Effect of thrust force on torque?

[PCarson85]

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?

 

[BvU]

Depending on the bearings, it will wear out pretty soon !

 

[berkeman]

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

 

[berkeman]

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.

 

[Dr.D]

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.