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Browse Prior Art Database

Compliance for auxiliary bearings

IP.com Disclosure Number: IPCOM000201296D
Original Publication Date: 2010-Nov-10
Included in the Prior Art Database: 2010-Nov-10
Document File: 2 page(s) / 153K

Publishing Venue

Siemens

Related People

Juergen Carstens: CONTACT

Abstract

Ball bearings are often used as backup bearings for rotors which are provided with active magnetic bearings. In case of a failure of one of the active magnetic bearings, the rotor can land on the auxiliary bearings. The induced forces are very high which can destroy the ball bearings. In general the stiffness and the damping of the ball bearings can be very low. Therefore, an additional support device is required to provide the bearings with the required stiffness and damping in order to increase the life time and allow a high number of landings. Up to now, a metal strip with a deflected shape is used which fills the small gap between the outer diameter of the ball bearing and the bearing housing. This solution is also called a Borelli ribbon. However, the use of the metal strip does not guarantee a long life time of the ball bearings or a high number of rotor landings.

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Compliance for auxiliary bearings

Idea: Gerard Korenblik, NL-Hengelo

Ball bearings are often used as backup bearings for rotors which are provided with active magnetic

bearings. In case of a failure of one of the active magnetic bearings, the rotor can land on the auxiliary

bearings. The induced forces are very high which can destroy the ball bearings. In general the

stiffness and the damping of the ball bearings can be very low. Therefore, an additional support device

is required to provide the bearings with the required stiffness and damping in order to increase the life

time and allow a high number of landings. Up to now, a metal strip with a deflected shape is used

which fills the small gap between the outer diameter of the ball bearing and the bearing housing. This

solution is also called a Borelli ribbon. However, the use of the metal strip does not guarantee a long

life time of the ball bearings or a high number of rotor landings.

Therefore, a novel solution is proposed which allows for tuning the desired stiffness and damping

capacity (see Figure 1). Several pre-stressed stacked spring strips are added between the outer

diameter or bearing houses of the ball bearing and the outer housing. The stiffness can be tuned or

added by changing the number and thickness of the spring strips. The damping is added by the friction

between the spring stri...