Practical Design Hints - SDP/SI Tech Library D220-T50

This case is analogous to the preceding. In this case both the radial and axial position of the bushing is overdetermined (a). To avoid the need for matching four dimensions between bushing and housing, add an axial and radial clearance, as shown in (b). This reduces the number of matching dimensions to two.

The same principle applies in the assembly of a hollow shaft and bushing. In (a) the mating shaft lengths have to match and this requires close tolerances. In design (b) the length of the reduced-diameter section of the male shaft has been slightly reduced, thereby eliminating the need for close tolerances.

Another example: the shaft-and-collar assembly (a). The need to match two radii (a) is reduced to one in the design (b).

Similarly, for the assembly of threaded tubing (a), arrange for clearance for the smalldiameter section of the male part, as in (b), to avoid the need for matching the O.4ùinch dimensions.

For the clamping of a housing with a nut and bolt, the thread on the reduced-diameter portion of the bolt should extend into the housing as in (b), so that the width of the housing does not have to match the length of the unthreaded portion of the bolt, as an (a). Design (b) avoid the possibility of the nut tightening against the bolt, rather than the housing.

T50