KeevoDrive^®

Ratio

The reduction ratio describes the relationship between the input movement and the output movement. With a reduction ratio, the output movement is smaller than the input movement.

Self-locking

With self-locking, the forces caused by friction are always greater than the applied adjustment forces due to the geometric relationships of the sliding partners. Due to the geometric conditions, the sliding partner in which the force is initiated cannot be moved relative to the sliding parter on which the adjustment force is applied.

Max. travel range

The travel range describes the travel range available for the application. The travel range characteristic describes the characteristic of the travel range as a function of the angular position of the eccentric. It is defined such that at an angular position of 0 degrees, the eccentric is perpendicular to the resulting movement direction and has no deflection in the adjustment direction. The max. travel range specifies the maximum available travel range of an eccentric kinematics.

Repeatability unidirectional

The unidirectional repeatability describes the positional uncertainty that arises when repeatedly approaching a setpoint from the same direction with no load. The repeatability is defined as half of the maximum difference together with a +/- sign.

Repeatability bidirectional

The bidirectional repeatability describes the positional uncertainty that arises when repeatedly approaching a setpoint from the opposite direction with no load. The repeatability is defined as half of the maximum difference together with a +/- sign.

Accuracy

The positioning accuracy of a gear describes the maximum deviation of the output angle relative to the setpoint or, with a linear actuator, the maximum deviation of the output position relative to the setpoint. The measurement is performed during a complete rotation of the output element or a complete traverse of the travel range path with the aid of a high-resolution measurement system. There is no change in the direction of rotation or direction reversal. The positioning accuracy is defined as the absolute value of the maximum difference between the theoretical setpoint position and the measured actual position of the output element.

Resolution

The positioning resolution refers to the smallest angular change or positional change that can be distinguished by the positioning system. With eccentric systems, the characteristic of the linearly resulting positioning resolution is described as a function of the angular position and thereby indicates the smallest positional change as a function of the angular position that can be distinguished by the positioning system. With eccentric systems, it is defined such that at an angular position of 0 degrees, the eccentric is perpendicular to the resulting movement direction.

Backlash

The backlash can be ascertained from the characteristic of the hysteresis curve of a gear or linear actuator. Backlash is defined as the range in which the characteristic of the hysteresis curve is vertical, i.e., an angular change or a positional change occurs without changing the torque or the force. The hysteresis curve is determined by subjecting the output to load while the input is blocked with a clockwise and an anticlockwise torque or a forward-acting and a backward-acting force and the corresponding angular displacement or positional change measured.

Rated force

Rated torque or rated force is defined as the torque or force at which the service life is achieved under rated conditions, i.e., rated speed. With drive systems, the motor torque may, in some cases, not be adequate for overcoming the running torque of the complete system under rated conditions.

Peak force

The peak torque or peak force is the loading of the components in the drive train, e.g., the teeth of the gears, still below the fatigue strength. This does, however, result in increased tooth wear, which leads to a reduction in the service life. With drive systems, the motor torque may, in some cases, not be adequate for overcoming the running torque of the complete system at peak torque or peak force.

Momentary peak force

With momentary peak torque or momentary peak force, the elastic deformations of the teeth are still small enough that no tooth meshing problems occur and proper function is ensured. The loads do, however, exceed the limit of the fatigue strength. Thus, the number of loads should be minimised. Should it occur once, breakage or failure will not result. With drive systems, the motor torque may, in some cases, not be adequate for overcoming the running torque of the complete system at momentary peak torque or momentary peak force.

Lifetime for rated operation

The service life is defined by means of the rated operating point, i.e., rated speed and rated torque, as well as a change of the accuracy characteristics, i.e., unidirectional repeatability, transmission accuracy, lost motion, of less than 10% of the respective catalogue value.

Radial backlash output shaft

Possible deflection of the mounted shaft in the radial direction without applied force.

Axial backlash output shaft

Possible deflection of the mounted shaft in the axial direction without applied force.

Radial stiffness

Stiffness of the bearing in the radial direction, i.e., elastic deflection of the mounted shaft in the radial direction as a function of the applied force.

Axial stiffness

Stiffness of the bearing in the axial direction, i.e., elastic deflection of the mounted shaft in the axial direction as a function of the applied force.

Max. radial load on output shaft (non-operating, constant load)

Max. permissible radial load on the output shaft (not in operation, force applied constantly) Describes the maximum permissible radial load on the output shaft, whereby the drive is not in operation, i.e., is at a standstill and the force is applied statically. The static load-bearing capacity of the ball bearings Co and the geometric relationships from the point of force application and the bearing distance are decisive for the determination. For the permissible force, the worst case is assumed as the point of force application, i.e., the maximum distance between the ball bearings and the end of the output shaft.

Max. radial load on output shaft (non-operating, impulsive load)

Max. permissible radial load on the output shaft (not in operation, force applied impulsively) Describes the maximum permissible radial load on the output shaft, whereby the drive is not in operation, i.e., is at a standstill and the force is applied impulsively. The load-bearing capacity of the ball bearings is decisive for the determination. With impulsive loading, the permissible load-bearing capacity of the bearings is reduced to one third of Co.

Max. radial load on output shaft (operating, constant load)

Max. permissible radial load on the output shaft (in operation, force applied constantly) Describes the maximum permissible radial load on the output shaft, whereby the drive is in operation and the force is applied statically. Particularly important for the determination of the permissible force in the dynamic case are, in addition to the load-bearing capacity of the ball bearings, the stiffness of the bearing and the run-out error on the dynamic spline caused by elastic deformation. For the permissible force, the worst case is assumed as the point of force application, i.e., the maximum distance between the ball bearings and the end of the output shaft.

Max. radial load on output shaft (operating, impulsive load)

Max. permissible radial load on the output shaft (in operation, force applied impulsively) Describes the maximum permissible radial load on the output shaft, whereby the drive is in operation, i.e., is turning, and the force is applied impulsively. With impulsive loading, the permissible dynamic load-bearing capacity of the ball bearings is reduced to one third of Cr. Likewise decisive for the determination are, in addition to the load-bearing capacity of the ball bearings, the elastic deformation of the output shaft near the dynamic spline and the associated run-out error due to the stiffness of the bearing.

Max. axial load on output shaft (non-operating, constant

Max. permissible axial load on the output shaft (not in operation, force applied constantly) Describes the maximum permissible axial load on the output shaft, whereby the drive is not in operation, i.e., is at a standstill and the force is applied statically. Decisive for the determination is the static load bearing capacity of the ball bearings as well as the elastic deformation of the output shaft due to the stiffness of the output bearing and the associated position of the dynamic spline.

Max. axial load on output shaft (non-operating, impulsive load)

Max. permissible axial load on the output shaft (not in operation, force applied impulsively) Describes the maximum permissible axial load on the output shaft, whereby the drive is not in operation, i.e., is at a standstill and the force is applied impulsively. Decisive for the determination is the static load bearing capacity of the ball bearings, which, in the impulsive case, corresponds to just one third of Co, as well as the elastic deformation of the output shaft due to the stiffness of the output bearing and the associated position of the dynamic spline.

Max. axial load on output shaft (operating, constant load)

Max. permissible axial load on the output shaft (in operation, force applied constantly) Describes the maximum permissible axial load on the output shaft, whereby the drive is in operation, i.e., is turning, and the force is applied statically. Decisive for the determination is the dynamic load bearing capacity of the ball bearings as well as the elastic deformation of the output shaft due to the stiffness of the output bearing and the associated position of the dynamic spline.

Max. axial load on output shaft (operating, impulsive load)

Max. permissible axial load on the output shaft (in operation, force applied impulsively) Describes the maximum permissible axial load on the output shaft, whereby the drive is in operation, i.e., is turning, and the force is applied impulsively. Decisive for the determination is the dynamic load bearing capacity of the ball bearings, which, in the impulsive case, corresponds to just one third of Cr, as well as the elastic deformation of the output shaft due to the stiffness of the output bearing and the associated change in position of the dynamic spline.

Moment of inertia

The moment of inertia specifies a body’s resistance to change its rotational movement.

Weight

The weight of the drive without cables and plugs.

Min. permissible ambient temperature (non-operating)

Minimum permissible temperature at which the drive may be stored or decommissioned without being impaired or destroyed as a result.

Min. permissible ambient temperature (operating)

Minimum permissible temperature at which the drive can be operated.

Max. permissible ambient temperature (non-operating)

Maximum permissible temperature at which the drive may be stored or decommissioned without being impaired or destroyed as a result.

Max. permissible ambient temperature (operating)

Maximum permissible temperature at which the drive can still be operated.

Maximum speed of motor

The maximum speed of the motor describes the speed before mechanical damages occur to the commutator, the rotor or the bearing.

Speed constant of motor

Describes the dependence between speed and applied voltage of the unloaded motor in the steady state, i.e., constant speed, at an ambient temperature of 20°C.

Stall torque of motor

Describes the torque developed by the motor while at a standstill.

Torque constant of motor

Describes the dependence between torque and current of the motor at an ambient temperature of 20°C.

No-load current of motor

Describes the current consumption of the unloaded motor in the steady state, i.e., constant speed, at an ambient temperature of 20°C.

Max. continuous current of motor

Maximum permissible current at which continuous operation of the drive is possible without the motor overheating while at an ambient temperature of 20°C.

Rated voltage of motor

The rated voltage corresponds to the voltage at which all other rated characteristic values of the motor, particularly the rated current at 20°C, are set, measured and classified.

Phase resistance of motor

The phase resistance describes the ohmic resistance of the coil of a phase at an ambient temperature of 20°C in the steady state.

Inductance of motor

Describes the inductance of the coil of a phase at an ambient temperature measured at 1 kHz.

Amplitude BEMF of motor

Describes the amplitude of the bemf.

Max. coil temperature of motor

The maximum temperature that may occur in the coil without destroying the magnets or the coil. The coil temperature can be calculated by measuring the change in resistance and the temperature coefficient alpha, which is dependent on the coil wire material. T1 = 1/alpha * (R1/R0 + alpha*T0 – 1)

Thermal resistance of motor between coil and housing

Describes the thermal resistance of the motor between coil and housing.

Thermal resistance of motor between housing and air

Describes the thermal resistance of the motor between housing and ambient air.

Thermal time constant of the coil of the motor

Describes the thermal time constant of the motor coil.

Thermal time constant of the housing of the motor

Describes the thermal time constant of the motor housing.

Eccentricity

The eccentricity is the distance of the rotary axis of the input shaft to the axis of the eccentric.

Max. radial load on eccentric bearing (operating, constant load)

For this value, the force application point is seen at the eccentric. Because of the eccentricity and due to the leverage and the radial force occurs a torque on the gear. Thus, at this value, the torque load capacity of the gear as well as the load capacity of the bearing is taken into account at the same time.

Flexure hinge ratio

Describes the ratio of an input-side movement to the output-side movement quantity that results from the lever kinematics of a flexure hinge.

Max. load on flexure hinges

Specifies the maximum force that may act on the flexure hinge without the exceeding the continuous fatigue strength limit value.

Angular position of eccentric at min. position

Specifies the minimum angle of the output shaft of the eccentric that may be set while in operation.

Angular position of eccentric at max. position

Specifies the maximum angle of the output shaft of the eccentric that may be set while in operation.

RoHS compliant

At Micromotion GmbH, hazardous materials, which are referred to in EU directive 2011/65/EU, are purchased/used only in compliance with this directive.