Bosch Rexroth MKE Series - Layout of Holding Brakes; Holding Brake-Commissioning and Maintenance Instructions

9.11.4 Layout of Holding Brakes
Holding brakes on motors of Rexroth are basically not designed for service
braking. The effective braking torques are different in static and dynamic op‐
eration for physical reasons.
Normal operation and EMERGENCY
STOP
Fault condition
In normal operation, using the holding
brake for clamping of a standstill axis, the
"static holding torque" (M4) - adhesive fric‐
tion applies.
In case of EMERGENCY STOP for the de‐
sactivation of an exis (n < 10 min
-1
), a
"dynamic holding torque" (M
dyn
) – sliding
friction is effective.
Under a fault condition, using the holding
brake for the desactivation of a moving ax‐
is (n ≥ 10 min
-1
), a "dynamic holding tor‐
que" (M
dyn
) – sliding friction is effective.
M4 > M
dyn
Therefore, note the following description of dynamic sizing.
Fig.9-22: Dynamic sizing
Dynamic sizing
The load torque must be smaller than the minimum dynamic torque M
dyn
which
the holding brake can provide. Otherwise the dynamic holding brake torque is
not sufficient to stop the axes.
If a mass is to be decelerated in a defined time or in a defined route, the addi‐
tional mass moment of inertia of the whole system must be taken into account.
Project planning recommendation
To ensure the system's safety, reduce the required holding torque to 60% of
the static holding torque (M4) of the holding brake.
9.11.5 Holding Brake–Commissioning and Maintenance Instructions
Before initial commissioning
In order to ensure proper functioning of the holding brake, it must be checked
before the motors are installed.
Measure the holding torque (M4) of the holding brake. If necessary, grind in the
holding brake.
Measure the holding torque (M4) of the holding brake
1. De-energize the motor and secure it against re-energization.
2. Measure the transferable holding torque (M4) of the holding brake with a
torque wrench. Holding torque (M4) see "Technical Data".
● If the holding torque (M4) indicated is achieved, the motor is ready
for the assembly.
● If the holding torque (M4) indicated is not achieved, the subsequent
grinding process can be used to reconstitute the holding torque.
Grinding in the holding brake
1. At closed holding brake, turn the output shaft by hand, e.g. with the help
of a torque wrench, by about 5 revolutions.
2. Measure the holding torque (M4).
● If the holding torque (M4) indicated is achieved, the motor is ready
for the assembly.
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Rexroth MKE Synchronous Motors | Project Planning Manual
Operating Conditions and Application Notes