Abstract:In order to study the influence of the compression amount of the main drive seal ring of the shield machine and the load of lubricating grease on the front and back sides of the seal ring on the sealing performance of the seal ring,the sealing performance of VD seal ring made of nitrile rubber (NBR) was studied under different compression amount and different loading pressures of the front and back sides of the seal ring.The results show that in the range compression amount from 3 mm to 7 mm,with the increase of compression amount, the maximum von Mises stress on the contact surface of the sealing ring increases at first and then gradually tends to be stable,while the maximum contact pressure on the contact surface is decreased.When the pressure difference is consistent,with the increase of the pressure on both sides of the seal ring,the maximum contact pressure on the contact surface of the VD sealing ring also maintains a similar amplitude increase. When the pressure on both sides of the sealing ring changes, the sealing ring structure ensures the margin of contact pressure, so as to ensure the stability of the sealing effect of the sealing structure.Through the surface response method, the VD seal ring with reverse support structure was optimized.It is concluded that the best sealing effect is obtained when the support angle is 9.345 3° and the support length is 59.499 mm under the compression amount of 7 mm and the pressure of 0.9-0.6 MPa on the front and back sides of the seal ring.After optimization, the maximum contact pressure of VD seal ring is increased by 16% to 25%.