Due to the long guidance basis of the guide bushings on a welded machine column, particular attention must be paid to ensuring a precisely flush housing borehole.
In a tailstock, minimal guide play can be achieved here during the installation process. Guide play readjustment is possible at any time. Grease lubrication with facility for occasional re-lubrication is sufficient here.
Guide play adjustment using threaded ring. A locating fit at the threaded ring ensures the necessary rectangular face contact at the guide bushing. The required feed path can be specified when the flange cover has not yet been tightened by turning the threaded ring. The guide bushing is then pre-stressed by tightening the screws at the flange cover.
In this example, the working sleeve of a machine tool is precisely guided by two FAK series guide bushings. In the stationary working position of the sleeve or column, clamping using the spring-hardened guide bushing guarantees absolute freedom from play as well as a high degree of radial rigidity in the guide system.
Safety requirements (power failures, oil pressure drop) or economic considerations (long clamping and short release times) often call for a mechanically acting clamp. In this case, the FAL series guide bushing is clamped using banks of cup springs (lower half of the picture) and hydraulically released (upper half of the picture).
In the arrangement shown here, an independent guide play setting is possible for each guide bushing. This allows the ever-present minimal influence of the different actual guide bushing dimensions and housing boreholes to be compensated. Where expedient for certain requirements, differing degrees of guide play can be set at the two guide bushings.
Competitiveness through technological leadership – a strategy that calls for an economical increase in power density, efficiency and accuracy. Guide bushings create the foundation for this.
- Low-cost, ready-to-mount guide and clamping bushing.
- Existing mating play ensures simple mounting even with large dimensions.
- Optimum guide play adjustment for any operating status.
- Metallic support between clamped sleeve and housing affords high radial rigidity.
- Provides typical high damping performance characteristics for slideways.
- Precise central play restriction and clamping of the sleeve or column.
First phase of axial pre-stress: Mating play between housing and guide bushing eliminated, firm fit realized.
After further axial pre-stressing, the guide play between the guide bushing and sleeve is optimally adjusted.
Mounting situation: Connection with assembly play between the housing, guide bushing and centre sleeve.
Guide play adjusted: The guide bushing fits firmly in the housing; guide play between guide bushing and sleeve is optimally adjusted.
Sleeve clamped: Absolute freedom from play between the sleeve and housing due to tensioned guide bushing.
- Transmittable Forces
In conjunction with the lubrication, the plastic coating of the guide bushings ensures smoothrunning, low-wear guidance. However, the good sliding properties of the bushing have a detrimental effect on the transmittable forces. Therefore the table values "transmittable forces" should only be regarded as non-binding guideline values.
F: Maximum permissible clamping force.
C: Required functional installation space
Spieth clamping sleeves must be clamped using the controlled application of force. The clamping force cannot be applied in relation to the clamping path. To prevent premature blocking, a "free" functional path "C" must be provided.
M: Transmittable torque at Fa = 0.
Fa: Transmittable axial force at M = 0.
The Fa values are calculated according to
M and Fa: If both torque and axial forces act on a guide bushing at the same time, check using the following formula whether the resulting torque Mr is transmittable:
If it is not possible to apply the clamping force F, the following formula is used for the approximate determination of the torque Mred which can be transmitted with the given clamping force Fgiv. (<F).
To ascertain the necessary clamping force for a transmittable torque Mred < M, an approximation is possible using the following formula:
M = Transmittable torque (catalogue value) [Nm]
Me = Required torque [Nm]
Mr = Resulting torque [Nm]
Mred = Reduced transmittable torque [Nm]
F = Max. perm. clamping force (catalogue value) [N]
Fae = Required axial force [N]
Freq. = Required clamping force [N]
Fgiv. = Given clamping force (<F) [N]
d1 = Shaft diameter [mm]
|Diameter in mm||Perm. radial stress(Guideline values)|
All information is supplied without liability and subject to technical changes. Please observe the operating instructions.
1) As the guide borehole is machined while the guide bushing is in a preloaded condition, control measurement of the guide bushing is not possible in its delivered, non-loaded state.
Designation of a guide bushing with integrate clamping screws, d1 = 60 mm, d2 = 85 mm and K = 42 mm: Guide bushing FSK 60.85.
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