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Installation of set screw type bearing unit

To install the set screw type bearing unit to the shaft, equally tighten two set screws to the recommended torque.

NTN ball-point set screws, having the construction as shown in Fig. 3, are hard to loosen even when subjected to vibrations or impact loads. If fitting clearance between the inner ring and the shaft is small, make a flat (as shown in Fig. 4) approx. 0.2 to 0.5 mm deep on an area of the shaft to which the ball point of the set screw is seated. This arrangement allows the tight-fit bearing to be easily removed from the shaft.

Fig. 3   Fig. 4

Install the bearing unit to the shaft

  1. First, make sure that the set screw does not protrude into the bearing bore.
  2. Hold the bearing unit with hands squarely to the shaft, and fit it over the shaft straight. Do not turn it. NEVER exert any impact to the bearing unit, nor hit the flinger (Fig. 5).
  3. Securely install the bearing housing to the specified position of the machines.
    Recommended torques for tightening hex. head bolt.
  4. Securely fit an Allen key wrench to the hexagonal socket of a set screw. Then, tighten the two set screws equally with a tightening torque that can be found in Table 2 (Fig. 6).
Fig. 5   Fig. 6

How to fix the set screws more securely

Use the following procedure to fix the set screws to the shaft more securely in cases where the bearing unit may undergo impact loads, the rotation rate is comparatively high for a bearing unit (dn = 30,000 or above), or continuous operation at low load (for example, belt tension only) will be performed.

  1. After securing the bearing housing and before tightening the set screws, tap on the housing lightly with a hammer made of wood or plastic. (This will prevent sticking between the bearing and shaft.)
    -> Perform the above procedure between steps 3 and 4 above.
  2. After trial operation of the machinery, retighten the set screws using the recommended torque as necessary.
    -> Perform the above procedure after step 4 above.