Bearing seal structure configuration options

Axis in two bearings in the radial and axial support, called bearing on one side of the fixed end bearing, it bear radial and axial load, the fixed axis and the relative axial displacement between the bearing box. To the other side is called the free end, only bear radial load, axial can move relatively. Bearing for high medium viscosity and good lubricity, p0. 8 mpa, or poor low viscosity and lubricity of medium, p0. 5 mpa, we usually choose the balanced structure. P value exceeds the scope, should consider to choose balanced structure. When p> 15 mpa, common single face structure balance it is hard to meet the sealing requirements, this time can choose tandem end face seal. Refers to the average diameter of circumferential velocity on sealing surface, according to the size of the value to determine whether elastic element with the axis of rotation, namely USES the rotary spring or spring stationary type structure, general < 20 ~ 30 m/s spring rotary can be used, under the condition of higher speed, due to the imbalance of the rotating parts quality easy cause strong vibration, had better use spring stationary type structure. If p and q value is high, can consider to choose the fluid dynamic pressure type structure. Fixed end bearing must be at the same time and the fixed shaft and bearing box, a suitable bearing is able to withstand radial composite load bearing, for example, deep groove ball bearing, spherical roller bearings, double row or diagonal contact ball bearing or tapered roller bearing. Bear the radial bearing combination of pure radial load, such as inside and outside the circle without a guard of cylindrical roller bearing and deep groove ball bearing, four-point contact ball bearing or two-way thrust bearing combination, also can be used as a fixed end bearing. At this point, the second bearing provide two-way axial positioning, but must keep bearing box when installing a radial interval. The free end bearing in shaft due to thermal expansion, the length changes, bearing inner extrusion will not occur. Axial displacement may occur within the bearing and also can produce bearing ring and bearing seat. According to the working parameters and dielectric characteristics of the selected structure is often just a preliminary scheme, bearing finalized must also consider the characteristics of the host and some special requirements for sealing. For example, the rocket engine seal life just a few minutes, but require a short period of time is not leak. The host on the ships sometimes in order to obtain a more effective space, to seal the size and location of the often very strict request, and as the drainage pump on the submarine, in the process of submarine ups and downs, large variations in pressure, etc. In these cases, there will be no structure by conventional selection standard, and must make a special design of specific conditions, and take necessary auxiliary measures.