hydraulik - Jahns-Regulatoren

4. Negative brakes
4.1 Negative brakes
The gearboxes can be supplied with a hydraulic negative brake:
- The brakes from model F01 to model F26 are for the direct mounting of orbit motors with SAE A fl anges.
- The brakes from model F501 to model F 612 reach greater braking torques and are mounted with a ST entrance
for the mounting of fl anges and connecting couplings for a vast range of commercially available motors.
- The brake models F813 to F830 achieve braking torques up to 3.050 Nm and come with the same direct input
assembly as the JPL 310/510.
- The MD brake is mounted directly into a connecting fl ange for the MLG - MLR motors on the JPL 110/JPL 240
gearbox.
Braking is generated by springs, which compress fi xed alternating tempered steel discs against bronze mobile
discs; this thrust is transformed by friction into a braking torque. Brake releasing is achieved by the injection of
hydraulic pressure into the brake; the pressure acts upon a piston, which compresses the springs, thus enabling the
disc to rotate freely.
The brakes are therefore static and closed when hydraulic pressure is zero and they open when the hydraulic
pressure reaches the opening values for release. The brakes are not lubrifi cated by the oil from the gearbox. It is
necessary to carry out the fi lling (approximately 0,1 l) with mineral oil of a viscosity ISO VG32; or as an alternative it
is possible to use hydraulic oils.
4.2 Brake selection
The following parameters must be taken into consideration:
- Braking torques are calculated with the pilot pressure = 0 bar; in the case of counter-pressures in the hydraulic
circuit, the effective torque values are reduced as follows:
Eff. Torque = Static Torque x (Opening pressure – Counter-pressure) / Opening pressure
- The brake torque must be greater or equal to that of the motor:
www.jahns-hydraulik.de
Tf T 1
- The brake torque multiplied by the reduction ratio and divided by the output of the gearbox, must be greater or
equal to output torque:
Tf • ie / ηm T 2
- The brake torque multiplied by the reduction ratio and divided by the gearbox effi ciency must not exceed 90% of
the impulse output torque of the gearbox.:
Tf • ie / ηm 0,9 T 2imp
5. Assemblypositions
In order to provide a complete defi nition of the constructive form of the gearbox, the assembly position must be
defi ned.
Based upon the position it is also possible to identify the oil fi lling, level and drain plugs. See page G.236 - G.238.
Page B. 11
H Y D R A U L I K