Technical Glossary

The air gap is the distance between the inner and outer rotor of a magnetic coupling — including the wall thickness of the containment shell. It directly influences the transmissible torque.

Mechanical play in the axial direction (along the shaft axis) of a bearing or guide.

Defined mechanical play between tooth flanks or guide elements — intentionally allowed for temperature and tolerance compensation.

Backlash j is the clearance between the working and non-working tooth flanks of two meshing gears — necessary for lubrication, thermal expansion, and manufacturing tolerances.

Precision linear motion element with a ball-bearing spindle for high efficiency and zero backlash.

Cage positive guidance is a mechanical synchronization system for the rolling element cage — prevents cage creep and runout during slow strokes.

The centre distance a is the spacing between the axes of rotation of two meshing gears. For standard gearing without profile shift: a = (d₁+d₂)/2.

Contactless torque transmission means the drive and driven sides share no mechanical component — the force is transmitted via a magnetic field.

The containment shell is the non-magnetic wall between inner and outer rotor of a magnetic coupling — enabling hermetic separation without a shaft penetration.

The crossed-roller guide contains cylindrical rollers arranged alternately at 90° — extremely stiff under loads from all directions.

The dynamic load rating C is the load at which a guide or bearing series reaches a defined nominal service life (typically 100 km of travel).

Eddy-current losses occur when a moving magnetic field induces currents in an electrically conductive component. In magnetic couplings they increase quadratically with speed.

Ratio of output power to input power (η = P_out / P_in) — measure of the energy efficiency of a component.

Gear hobbing is a continuous generating process using a helical hob — the most economical method for medium to large gear series.

Gear quality specifies the accuracy class of a gear per DIN 3961/3962 or ISO 1328 — the lower the class number, the more precise the gear.

Ratio of input speed to output speed (i = n₁/n₂) of a gearbox.

Gear shaping is a generating process in which a gear-shaped cutter performs a combined stroking and rolling motion — ideal for internal gears.

Ratio of output power to input power specifically for gearboxes — affected by gear mesh losses, bearing friction, and lubrication.

Gear tooth form with angled teeth for quieter operation and higher load capacity than spur gearing.

Hermetic sealing denotes absolute impermeability to gases and liquids — achievable via magnetic couplings with a containment shell.

A hypoid gear is a bevel gear in which the axes of the two bevel gears do not intersect at a point but are offset from each other.

The hysteresis coupling transmits its torque through a hysteresis material rather than fixed pole pairing — delivering a slip-independent constant torque.

In involute gearing, each tooth flank follows the involute of the base circle — the standard gear form in mechanical engineering today.

Standardized classification of enclosure protection against solid particles and liquids (IEC 60529).

The linear distance a nut or screw advances per one full revolution — determines the ratio between rotational and linear motion.

In line contact, a cylindrical roller touches the raceway along a straight line — distributing the load over an area for higher load ratings.

Guidance system for linear motion — available in profiled rail, round shaft, or telescopic designs.

A magnetic coupling transmits torque without contact via a magnetic field from a drive to a driven shaft — with no mechanical connection.

The module m is the ratio of the reference circle diameter d to the number of teeth z (m = d/z) in millimeters — determines tooth height and circular pitch.

The operating pitch circle is the circle on which two meshing gears roll on each other without slip during operation.

The torque delivered at the output side of a gearbox — the product of input torque, gear ratio, and efficiency.

Pitting refers to small shell-shaped craters on the tooth flank caused by rolling contact fatigue — caused by excessive Hertzian contact stress.

POM (polyoxymethylene, also polyacetal) is a semi-crystalline thermoplastic widely used as a gear material in precision mechanics.

The pressure angle α is the angle between the line of action and the tangent to the pitch circles. Standard value: 20°.

Profile shift moves the tool reference profile radially relative to the blank during gear cutting — improves load capacity and undercut behavior.

The pull-out torque is the maximum torque a magnetic coupling transmits before the magnetic coupling breaks and the coupling slips.

Force acting perpendicular to the shaft axis on a bearing or guide.

The speed of a motor or gearbox specified for rated operation, at which rated torque and power apply.

The maximum continuously transmissible torque of a drive or gearbox component under rated conditions.

The reference circle with diameter d = m·z is the base circle of the individual gear, on which module and circular pitch are defined.

In roller recirculation, the rolling elements circulate in a closed path within the carriage — enabling theoretically unlimited travel distances.

Rolling elements are the rolling components between two raceways in guides and bearings — they transmit loads and minimize friction.

Property of a gearbox in which a load on the output side cannot back-drive the gearbox — a load-holding system without a brake.

The service life L10 is the nominal service life (in km of travel) reached by at least 90 % of all guides in a series without fatigue failure.

The static load rating C0 is the maximum permissible static load at which no permanent (plastic) deformation of the rolling elements or raceways occurs.

The stiffness of a linear guide describes its resistance to elastic deformation under load — significantly higher for roller guides than ball guides.

The permanent-magnet coupling carries permanent magnets on both sides that couple pole-to-pole and transmit torque without contact.

Tooth root strength is the resistance of a gear to fracture caused by bending stress at the tooth root — verified per ISO 6336/DIN 3990.

Rotational force that generates or transmits a turning motion. Unit: Nm.

Science of friction, wear, and lubrication — the basis for optimized lubricant selection and maintenance planning.

Undercut is the unintended removal of material at the tooth root during gear cutting — weakens the tooth root and occurs with small numbers of teeth.

Condition with no measurable mechanical play in a drive or guide element — prerequisite for precise positioning.