INA needle bearing are roller bearings with cylindrical rollers. Relative to their diameter, the rollers are thin and long. This roller is called a needle roller. Although it has a small cross-section, the bearing still has a high load-bearing capacity, so it is especially suitable for occasions with limited radial space according to the situation where the use of radial space is limited. Depending on the application, different applications are available. Bearings or needle rollers and cage assemblies without inner rings can be used.
At this time, the journal surface and the housing hole surface that match the bearing are directly used as the inner and outer rolling surfaces of the bearing. The load capacity and running performance are the same as those of a bearing with a ferrule. The hardness, machining accuracy of surface of the shaft or housing hole raceway should be similar to the bearing raceway. This type of bearing can only support radial loads.
Essential elements of choosing INA needle bearing
When designing a new spindle, before selecting INA needle bearing, first consider the spindle performance parameters, roughly determine the analytical performance, and then enter further exploration. (Including spindle speed, spindle accuracy, spindle rigidity, spindle life, spindle head, spindle reliability)
After determining the parameters of the spindle, probe the actual dimensions of the rod (shaft diameter, length, bearing span).
According to the bearing type (ball or cylindrical roller bearing), arrangement (number of agreement), driving method (drive belt, gear, motor, built-in motor), lubrication (grease, oil, and gas, oil mist, injection) and other spindle parameters are determined. Its structure.
1.Bearing radial load
Radial bearings are the INA bearings that mainly carry radial loads. The nominal contact angle of this taking a0 <= 450. Roller bearings with the same ruler rain can withstand larger radial loads than ball bearings.
N-type and NU-type cylindrical roller bearings can only support radial loads. Other types of radial bearings can support both radial and axial loads.
2.The axial load of bearing
The bearing that mainly bears axial load is generally a thrust bearing, and its nominal contact corner a0> 460. Thrust bearings and thrust angular contact ball bearing can bear axial forces in one or two direction at the same time, depending on the structure. When the bearing force is particularly high, thrust cylindrical roller bearings and thrust spherical roller bearings are preferred.
Thrust spherical roller bearings and unidirectional thrust angular contact ball bearings can support both axial and radial loads. Other thrust bearings can only support axial loads.
3.The length compensation of the bearing itself
A shaft and a bearing are usually sponsored by a combination of a fixed bearing and a movable bearing. The floating INA bearing compensates for shaft length errors and thermal expansion.
NU-type and N-type cylindrical roller bearings are ideal movable bearings; these bearings can compensate the length itself. The inner and outer ring of the bearings can be used with a tight fit.
4. Length compensation for sliding fit
Non-separable bearings can also be used as floating bearings. One of the two bearing rings of this type of bearing is fitted with no axial fixing surface. Therefore, a bearing ring can move on its bearing surface.
After determining size and type of precision bearing, consider the specific design of the bearing.
Thoroughly consider the bearing fatigue life, rigidity, heat, and other factors, and select an appropriate bearing clearance (preload).
Due to bearing clearance and preload, the performance of INA bearings is critical, and it becomes more significant at higher speeds, so it must be carefully considered. If it is not selected correctly, problems such as early damage or sintering may occur. It is necessary to think twice from step 4 to step 3, or from level 4 to step 2.
After determining the design of the spindle structure, the necessary conditions for actual installation must be considered.
Confirmation of the accuracy, tolerance fit of the mounting shaft and bearing housing of high-precision bearings, the tightening force of the set nut required for installation and fixation, the INA bearing preload and the internal clearance after the actual installation