It consists of a washer-shaped raceway ring with a raceway and a ball and cage assembly. The raceway ring that matches the shaft is called a shaft ring, and the raceway ring that matches the shell is called a seat ring. The two-way bearing matches the secret shaft of the middle ring. The one-way bearing can bear one-way axial load, and the two-way bearing can bear two-way axial load (neither can bear radial load).