WATER LUBRICATED CONICAL TYPE TEFLON BEARING

This invention relates to "Water lubricated conical type Teflon bearing"
The problem with the already existing oil lubricated bearings is that when they are subjected to high speed, more amount of heat is generated and the oil viscosity drops down and hence there is no lubricating effect which means that the film forming ability of the oil is lost and the bearing wears away soon. As the speed increases the co-efficient of friction also increases and it is reduced in our case with the value similar to a roller bearing. But roller bearings also wear in out at higher speed. The methodology we used to eradicate all the above mentioned problems is by using virgin Teflon as bearing material and shaft of mirror finished stainless steel with water as lubricating medium. Water performs two important functions, in case of low speed applications it removes the generated heat and lubricating action is performed by Teflon itself which is a very good solid lubricant. In case of high speed applications water removes the heat and also forms a thin film at the Teflon -stainless steel interface which reduces the friction further.

The arrangement consists of a high speed mixer motor (15000-18000rpm), High grade G-3i6 stainless steel shaft coupled to the said motor. Teflon bearing, bearing block, base plate and provision for water lubrication. One end of the stainless steel shaft is tapered and bearing material is also tapered in order to fit the tapered end of shaft. The bearing is clamped to the bearing block in order to prevent the relative motion with the shaft. A suitable clearance is provided between the Teflon bearing and the tapered end of shaft in order to provide hydrodynamic lubrication technique. A hole is drilled on the top of the bearing block and through bearing up to the shaft to ensure water to peach the bearing- shaft clearance. A provision is made to facilitate continuous supply of water to the clearance space from the water storage tank. The motor is mainly used in order to demonstrate the lubricating effect of water at high speeds. As the motor is switched on, the stainless steel shaft supported on the conical bearing starts to rotate at slow speed and attains a speed around 13,000rpm. At low speed, Teflon itself acts as an solid lubricant while water is used to remove generated heat whereas at high speeds water is used as an lubricating agent forming an thick film in between the clearance.

Referring to FIGURE-1,
The motor 1 is coupled to the stainless steel shaft 3 with the help of the coupling 2. The tapered end of shaft is fixed to Teflon bearing 4 which is fixed inside the bearing block 5. The drilled hole 6 ensures supply of water from water tank 7 to clearance space. The whole arrangement is placed on the base plate 8. When the motor 1 is switched on the high grade G-316 stainless steel, shaft 3 also rotates with it and the Teflon bearing 4 acts as an solid lubricant at low speed and at high speed water from storage tank 7 does the lubrication action by entering through the drilled hole 6 to the clearance space.
FIGURE-1 shows the principle of operation of the water lubricated conical Teflon type bearing.

Claims:

Having thus described the invention, we claim:

1. Water lubricated Teflon bearing comprises of conical Teflon bearing, tapered shaft mounted on said bearing, provision for water lubrication and a motor for demonstrating the bearing effect.

2. Teflon is used as bearing since it has no additive, operates well between - 260°C and 260°Cand its poor wear resistance properties can be improved by adding fibres like glass, ceramics, metal powders, graphite etc.

3. The improvement set forth in claim 2 includes low viscosity coefficient and self lubrication property,

4. High grade G-316 stainless steel is selected for shaft due to its high corrosion resistance and moreover Teflon is a good solid lubricant.

5. The friction coefficient of Teflon stainless steel pair is 0.04 under dry conditions. This combination has the lowest value friction co-efficient among the every other pair.

6. The relatively lower viscosity of water results in the reduced bearing load capacity when compared to oil for the same eccentricity ratio, therefore, most suitable when speeds are high or loads are low.

7. The improvement set forth in claim 6 includes its suitability for high speed and low load application that is for supporting high speed grinding wheel spindles that take very light radial loads when the precision grinding operation is done.

8. Water lubricated conical type Teflon bearings is described and illustrated in the figure of the accompanying diagram.