Thrust and radial bearing assembly

A combined radial and thrust bearing assembly for a downhole drilling assembly comprising:

• a fixed housing;
• a rotatable shaft extending through the housing;
• an upper pair of inner races fixed on the shaft and collectively forming a portion of an upper ball channel;
• at least one lower pair of inner races fixed on the shaft and collectively forming an outwardly facing portion of a lower ball channel;
• an upper pair of outer races mounted in the housing and collectively forming an inwardly facing portion of the upper ball channel;
• at least one lower pair of outer races mounted in the housing and collectively forming an inwardly facing portion of the lower ball channel;
• a plurality of bearing balls in the upper ball channel;
• a plurality of bearing balls in the lower ball channel;
• means for preventing rotation of the outer races relative to the housing;
• a pair of belleville springs between the upper outer races and the housing for transmitting an upwardly directed thrust from the upper outer races to the housing;
• a pair of belleville springs between the lower outer races and the housing for transmitting a downwardly directed thrust from the lower outer races to the housing;
• and
• spring means disposed between the upper and lower outer races, the spring means in cooperation with the belleville springs distributing thrust loads substantially equally between the upper and lower pairs of outer races.

A combined radial and thrust bearing assembly for a down-hole drilling assembly comprising:

• a fixed housing;
• a rotatable shaft extending through the housing;
• upper and lower pairs of inner tracks fixed to the shaft, each pair of inner tracks defining an outwardly facing portion of a channel adapted to support a plurality of bearing balls;
• at least one upper outer bearing race in the housing having a diagonally extending track engaging the bearing balls in the upper channel and having an axially compliant connection to the housing for transmitting a first thrust load to the housing;
• at least one lower outer bearing race in the housing having a diagonally extending track engaging the bearing balls in the lower channel and having a compliant connection to the housing for transmitting a second thrust load substantially equal to the first thrust load.

A ring-shaped race for a combined radial and thrust bearing assembly comprising:

• a plurality of upper lands and grooves forming crenelations on an upper end of the ring;
• a plurality of lower lands and grooves forming crenelations on the lower end of the ring, the upper and lower crenelations being substantially the same;
• an annular upper ball track between the upper crenelations and the middle of the ring and having a diagonally extending face;
• and
• an annular lower ball track between the lower crenelations and the middle of the ring and having a diagonally extending face, the upper and lower ball tracks being substantially the same.