needle bearings

Description

1. Needle roller bearings are roller bearings with cylindrical rollers which are thin and long in relation to their diameter. They are referred to as needle rollers. In spite of their low cross section the bearings have a high load carrying capacity and are thus extremely suitable for bearing arrangements where radial space is limited. 2. Needle roller bearings have a high load carrying capacity in addition to their low cross-section and stiffness. They are especially suitable for bearing arrangements where radial space is limited. Because needle roller bearings only carry pure radial load and can not limit the axial displacement of shaft relative to the housing. It is important to ensure that inner ring axis and outer ring axis must be aligned during mounting the bearings. 3. Drawn cup roller clutches are designed to transmit torque between the shaft and housing in one direction and allow free overrun in the opposite direction. When transmitting torque, either the shaft or the housing can be the input member. Precisely formed interior ramps provide surfaces against which the rollers wedge to positively transmit torque. Transition from overrun to lock normally occurs with minimal lost motion (backlash). Drawn cup roller clutches are offered as a clutch-only unit or as a clutch and bearing assembly. Clutch-only units should be used with external radial support to hold the shaft and housing concentrically and carry radial loads. 4. Heavy-duty needle roller bearings consist of a machined and ground channel-shaped outer ring with a complement of needle rollers retained and guided by a cage. The thick outer ring provides maximum load capacity and shock resistance with a relatively small radial cross section. With the high-strength cage retaining and guiding the rollers, this design provides high speed and lubrication retention capability. A lubrication groove and hole in the O. D. Facilitate relubrication through the outer ring.