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Edition 09.2007Page

Hydraulically actuatedclutches and brakes


PageGeneral notesClutchesOperation 5.03.00Properties 5.03.00Installation 5.03.00Circuit recommendations 5.04.00Application examples 5.05.00

BrakesOperation 5.06.00Properties 5.06.00Installation 5.06.00Circuit recommendations 5.07.00Application examples 5.08.00

Clutch/brake combined unitsOperation 5.09.00Properties, areas of application 5.09.00Installation 5.10.00Circuit recommendations 5.10.00Application examples 5.11.00

Product data sheetsTorque ratings Series 0023, 0123 5.13.00Clutch/brake combined units Series 0023, 0123 5.14.00Multi-plate clutches Series 0127 5.19.00Multi-plate brakes Series 0128 5.23.00Multi-plate clutches for wet-running, standard version Series 0021-007 5.27.00Multi-plate clutches, with shoulder housing,version for high torques Series 0021-3.3 5.29.00Multi-plate clutches, with flange housing,version for high thermal loading Series 0002-8.1 5.31.00Multi-plate clutches, with shoulder housing,version for high thermal loading Series 0002-8.3 5.32.00Spring-applied multi-plate brakes, non-centering version Series 0022-..0/..9 5.33.00Spring-applied multi-plate brakes, centering version Series 0022-..1 5.37.00Spring-applied multi-plate brakes, version withtwo different internal centerings Series 0022-320/620 5.41.00HydroSec safety multi-plate brake Series 0022-601 5.43.00

AccessoriesRotary inlets for pressure oil, single channel for series 0023, 0123 5.45.00Rotary inlets for pressure oil, two- and three-channel for series 0023, 0123 5.46.00Cover for series 0023, 0123,

0127 5.49.00Hydraulic press safety valve for series 0023, 0123,

0127, 0128 5.51.00

EN 5.01.00

Edition 09.2007PageGeneral notes



Hydraulically actuatedclutches and brakes

Clutch engagementPressure oil is led into the cylinder space of theclutch via the oil inlet (5). The piston (3)compresses the plates (2) against the stop plate(1), so that the clutch is frictionally engaged.

DisengagementWhen the pressure oil is depressurized, the returnsprings (4) push the piston (3) back to its initialposition so that the clutch is disengaged.

Important: In the case of clutches with a singlepiston, there is the risk that the clutch will beengaged unintentionally through the centrifugalforce acting on the oil in the cylinder. Reliabledisengagement of the clutch can only be ensuredat speeds below the nmax cylinder stated.

PropertiesThanks to the large piston forces produced by thehydraulic actuation, hydraulically actuated multi-plate clutches can provide high torques fromsmall dimensions. The oil-cooled plates with thefriction combination steel/sinter are effectivelywear-free; the small amount of running-in wear iscompensated for automatically by the piston sothat readjustment is not required.

InstallationIn order to avoid oil leakage, the h6/H7 shafttolerance that is recommended should bemaintained. In order that engagement is carriedout without delay, it is important that - amongstother things - the oil inlet holes in the shaft are ofan adequate size. The volume of oil required bythe clutch for engagement and the length of thepiping should be taken into account whenselecting the cross sections of the pressure oilpipes. Return-flow pipes are to be designed insuch a way that the resistance is as low as possible.In order to prevent subsequent faults and failureof the hydraulic system, absolute cleanlinessmust be maintained during installation.

Pressure oil supplyThe piston seals are metal rings with a rectangularsection. There is only a limited amount of buttclearance but this nevertheless permits a smallamount of oil to leak out, the amount of leakagebeing a function of the clutch size. For this reasoncare must be taken that the output of the pump isadequate for the size and number of clutches. Theamount of oil required by the clutches shouldcover engagement and leakage under all operatingconditions. It is essential that the full operatingpressure is available at the end of each engagementprocess.

Where large quantities of oil are required forclutch engagement and where the frequency ofengagement is low, consideration should be givento the use of an automatic double pump. Whenthe clutch is engaged, only the small pump is inoperation and circulates just the amount of oilthat is required to maintain the oil pressure.Under certain circumstances the fitting of anaccumulator upstream of the clutch fulfils thesame purpose.

The design (size) and position of the oil tankshould be selected in such a way that the heatgenerated during engagement and absorbed bythe oil can be dissipated freely into theenvironment.

EN 5.03.00

Edition 09.2007Page

Hydraulically actuatedclutches and brakes

General notes

Rotary inlets for pressure oilA rotary inlet, the design of which is appropriatefor each particular application, is required forintroducing the pressure oil into the clutch shaft.You will find information on single-channel rotaryinlets on page 5.43.00.Catalogue section 9 "Rotary inlets" provides detailson a wider selection of different rotary inlets.

Circuit recommendationsa Suction filterb Pumpc Electric motord Pressure relief valvee Directional control valvef Variable flow restrictor

Standard circuit for clutches requiring intensiveinternal oilingIf, as the result of the high level of friction work or the highfrequency of engagement, the amount of heat generated bythe clutch is high, an adequate amount of cooling oil isrequired to dissipate this heat. The circuit differs from thestandard circuit in that it has a separate internal oil supplyfrom a second pump.

Standard circuitThe suction pipe with filter (a) of a precision gear pump (b)is immersed in the oil bath of the machine. This pumpdelivers the oil to the directional control valve (e).When the clutch is engaged, the excess quantity of oil that isdelivered flows via a pressure relief valve (d) into the internallubrication line (i). The amount of cooling oil can be regulatedwith the variable restrictor (f).

In our technical product information forhydraulic clutches you will find comprehensivenotes on the installation and maintenance ofclutch systems.

h Restrictor non-return valvei Internal lubrication lineK1 K2 Clutch cylindersl Accumulator

EN 5.04.00

Edition 09.2007Page

Hydraulically actuatedclutches and brakes

General notes

Circuit for delayed engagementA throttle non-return valve (h) and a spring accumulator(l) are positioned downstream of the directional controlvalve. When the clutch is engaged, the restrictor and thevolume of the accumulator, which has to be filled, roducea delayed build-up of the clutch pressure and hence theclutch torque. The oil can flow rapidly out of the clutchwhen it is disengaged, via the non-return valve.

Application example

Hydraulically actuated OrtlinghausSinus multi-plate clutch, frictioncombination steel/sintered lining,fitted in a machine tool gearbox.

Circuit for smooth engagementThis circuit contains, as additional items, a spring accumulator(l) and an adjustable restrictor (f1). When the clutch isengaged, the volume of oil in (l) brings the piston rapidlyinto contact with the plate stack. Restrictor (f1) determinesthe rate of the torque increase. The sizes of the springaccumulator and restrictor must be selected in accordancewith the particular application.

EN 5.05.00

Edition 09.2007Page

Hydraulically actuatedclutches and brakes

General notes



This closed version can befitted on an extended shaftjournal outside the gearbox.

With the open flange asabove, the brake can befitted on a continuousshaft, e.g. inside a gearbox.

standard; further components can be protectedagainst rust on request. The pressure to releasethe brakes lies between 10 and 50 bar; in additionthey can be pressurised to a maximum of 320 barfor short periods of time. As a result of the spring-applied braking process which occursautomatically when either the oil is depressurisedor the pressure oil supply fails, they can be usedas safety brakes, in particular in lifting gear. Incases where the pressure oil supply fails, the brakecan be released manually with the aid of thejacking screws (7).

InstallationThe oil feed pipes and the return lines must be ofadequate dimensions if a delay-free application/releasing of the brake is to be ensured. The returnlines should offer the least possible resistance toflow. If manual release of the brake is requiredusing the jacking screws (7), the brake must beinstalled in such a way that there is sufficientspace to access them. In order to prevent faultsin the hydraulic system, it is important thatabsolute cleanliness is maintained duringinstallation.

Different versions are available to suit differentinstallation situations. These are shown in thefollowing examples.

Non-centering version,series 0022-..0/..9

BrakingThe brake is applied when it is in its de-energizedstate. The axial force of the springs (5) pushes thepiston (6) which in turn compresses the platestack (2) against the stop plate (1) so that africtional connection is produced.

Releasing of the brakeThe pressure oil is fed into the brake through thenon-rotating cylinder (4). The piston (6) movesagainst the pressure of the springs; the brake isreleased.

PropertiesHydraulically released, spring-applied multi-platebrakes are characterised by the low amount ofspace they require, the low moment of inertia ofthe rotating parts and by the high application


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