Fig. 142. Hyatt Roller Bearing
[Fig. 142] shows the Hyatt flexible type of roller bearing. This type consists of an inner and outer race and a cage which holds the flexible rolls. The flexible rolls are spirally wound from a high grade sheet alloy steel. The rolls are placed in the cage in alternative positions. This arrangement of rollers has a tendency to work the grease back and forth on the surfaces of the races. Another advantage claimed for this type of bearing, is that the weight is more evenly distributed at the point of contact, due to the fact that the wound rolls allow a certain amount of resiliency, and accepts road shocks easily, which reduces the amount of frictional wear to a minimum. This type of bearing requires the same attention as the Bock, described above.
Fig. 143. Double Row Radial Ball Bearing
[Fig. 143] shows a type of double row ball bearings. Ball bearings are being used more extensively each year by the manufacturers of light and heavy duty motor vehicles. The efficient reliability and ease of action has proven to be the main factor in the development of this type of bearing. One of the big features in considering ball bearings is that a ball rolls equally well in any direction, and the slightest effort will start it to rolling. It is a proven fact, that a ball is started more easily than any other type of supportive element. This explains why ball bearings of all types come nearest to being frictionless. Once upon a time people believed that the ball in ball bearings carried the load by point of contact, which is not true, as ball bearings carry the load on a definite area. And in bearing construction, such as shown in [Fig. 143], where the inner and outer race curves around the balls and increases the contact area, the contact capacity is greatly increased. Thus a one-fourth inch S. K. F. ball showed a crushing resistance of nine thousand and seven hundred pounds, while the one-half inch ball showed a crushing strength of twenty-five thousand pounds. The sectional view of a radial bearing, shown in [Fig. 142], consists essentially of four elements, which are the following: (a) The outer ball race, (b) the two rows of balls, (c) the ball retainer, and (d) the inner ball race.
The inner surface of the outer race is spherically ground in the form of a section of a sphere whose center is the center of the axis of rotation. This provides that both rows of balls shall carry the load at all times. This reduces the load carried by each ball to the least amount.
The ball retainer is made of a single piece, which provides for proper spacing of the balls, and positively circulates the lubricant. The retainer is open at the sides, which permits free access of lubricant, and makes inspection easy.
The inner ball race contains two grooves to accommodate the two rows of balls, and the curvature of the outer race is slightly larger than that of the balls. The fact that both inner and outer races are curved gives an ample surface contact between the balls and the races.
[Fig. 144] shows a double thrust bearing. This type of bearing was designed to take end thrust in both directions. It is used to stabilize the shaft against lateral motion and to accept reversing thrust loads. It is also automatically self-aligning.