MAHR - Шариковые направляющие Marmotion - 2010 Английский язык

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                                                       MarMotion. High-precision rotary stroke bearings                +

                                                                                                         43 Mahr

5. Computation of the Rotary Stroke Bearing

5.2 Loading capacity with radial load

The radial load of a rotary stroke bearing is determined by the position of the point of application of the radial force PR in relation
to the center of the contact length e.

The radial force PR can also be the resultant of several forces. The forms of radial load illustrated below depend on the position
of the point of application of the force.

The illustrations shown below take into account the deflection of the rotary stroke bearing under load which results from the elastic
deformation of the balls and rolling faces of the guide bush and shaft. The axes of the guide bush and shaft are assumed to be rigid.
The deflection of the shaft must therefore be incorporated into the calculation if necessary.

Load of the rotary stroke bearing by                                                                Combination

                                      Centrally acting                     Pure                     of radial force PR
                                                                           moment M                 and moment M
                                      radial force PR                      (see 5.2.2)
                                      (see 5.2.1)                                                   (see 5.2.3)

Guide shaft fixed,
guide bush moving

Guide bush fixed,
guide shaft moving

          Load of ball zones          Equal load                           The two end zones        One end zone
                                      on all zones                         of the contact length    of the contact length
Fig. 22                               of the ball cage                     carry the heaviest load  carries the heaviest
                                                                                                    load

The static radial load can take different forms:

1. The radial load is constant and evenly distributed and corresponds to a centrally acting radial force PR.

2. The radial load is distributed unevenly over the length. In certain special cases, it comprises a pure moment M.

The various forms of radial load lead to different stresses on the individual ball zones. Computation of the loading capacity is based
on the determination of the highest portion of radial force P10 of a ball zone 10 mm long. The relationships between the external
load PR or M and this specific radial force P10 are given below for various forms of static radial load.

The elastic deformation of the ball zones results in a deformation of the rotary stroke bearing axis. The elastic deformation of the
individual ball zones varies depending on the load. With a specific radial force P10, the radial deflection of the axis of the 10 mm
ball zone which is under maximum load is defined as the specific deflection A10. This value can be used to calculate the shaft
deflection which can be expected at the force application point A.

5.2.1 Uniform constant radial load                      P10  =  PR   10   [N]  PR in N, contact length e in mm
The radial force portion of every 10 mm ball zone is:           e               P10 in N, R10 in m/N from table (Fig. 27 or 28).
The expected parallel displacement of the axis is:
                                                        A10 = P10 · R10 [m]

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