The ball screw and rolling friction clutch piece, should avoid hard dust or dirt into the chip, and therefore must be equipped with protective device. If the ball screw is exposed on the machine, a closed shield shall be used, such as a coil spring, a steel sleeve, a telescopic sleeve, and a collapsible sleeve. When the utility model is installed, one end of the protective cover is connected with the side of the ball nut, and the other end is fixed on the supporting seat of the ball screw rod. If the ball screw is in a concealed position, the sealing ring can be used and the sealing ring is arranged at both ends of the nut.
Contact type elastic sealing ring made of rubber or nylon with high oil, the inner hole made with screw thread raceway shape matching; dustproof effect contact seal ring is good, but because of the existence of the contact pressure, the friction torque increases slightly. The non-contact sealing ring is also called labyrinth sealing ring. It is made of hard plastic. The inner hole is opposite to the screw thread and raceway, and has a little gap, so it can avoid the friction torque, but the dustproof effect is poor. Avoid collision protection device work, protection device damage should be promptly replaced.