Self-synchronizing clutch

The self-synchronizing clutch , synchro-self-shifting clutch , abbreviated as SSS clutch , is a freewheel in which the torque is transmitted with the help of a toothed clutch that is engaged by a pawl freewheel installed in parallel . It is suitable for transmitting higher torques than with a classic freewheel and is used, for example, in ships and power plants .

construction

The shaft end of the drive is provided with the thread of the helical gear, on which the slider sits, which carries the inner gear of the toothed coupling on the outside at the end against the drive shaft, at the end against the output shaft the ratchet wheel of a pawl freewheel. The output shaft is provided with a coupling sleeve which encompasses the sliding piece and which carries the internal toothing for the toothed coupling on the side against the drive shaft and which carries the pawls of the freewheel on the output side.

function

The two toothed portions of the tooth clutch during engagement by the drive torque  by means of a  helical  slid together, pulled apart again when disengaging the clutch of the higher speed of the output. The slider of the helical  gear is held in the uncoupled state by a pawl freewheel on the output shaft.

Engage

When the input shaft is rotating and the output shaft is stationary, the ratchet wheel of the slider on the input shaft pushes against the pawls on the coupling ring of the output shaft and is held by this, so that the thread of the rotating input shaft moves the slider axially into the coupling position and the toothed coupling engages. In this position, the pawls are no longer engaged and the power from the drive is completely transmitted by the toothed coupling. With large couplings, oil dampers are sometimes integrated in the end stop of the slider, which dampen the coupling.

Disengage

If the drive is slowed down compared to the output, the resulting braking torque causes a tooth flank change in the gear coupling. The slider is held by the output shaft and screwed back by the thread on the slower rotating drive shaft, so that the tooth clutch is opened and the pawls slide over the teeth of the ratchet wheel. If the speed difference is very high, the pawls are lifted off due to centrifugal force and hydrodynamic effects, which is desirable to reduce wear.

Manufacturer

There are only a few manufacturers of self-synchronizing clutches. The most important are:

• SSS Clutch Company, USA and SSS Gears Limited, England
• RENK-MAAG GmbH, Switzerland, subsidiary of Renk AG

application

The most important applications of the self-synchronizing clutch are listed below.

British County-class destroyer that first used an SSS coupling.

Shipbuilding

Self-synchronizing clutches are used for the following applications in shipbuilding :

• Coupling of several drive turbines to a common shaft train that drives the propeller
• Coupling of energy recovery turbines to the drive shaft

Power plants

Shafts of the Huntorf power plant in which two SSS couplings are installed - one for 300 MW and one for 80 MW.

Self-synchronizing clutches are used for the following applications in power plant construction:

• Coupling of the steam turbine to the drive train in combined cycle power plants that are designed as single-shaft systems
• Coupling of two gas turbines to a common generator
• Coupling between generator motor and turbine or compressor in a compressed air storage power plant
• Coupling between gas turbine and generator, so that the generator can be used as a phase shifter without being driven by the gas turbine .

Other

Self-synchronizing clutches are also used for the following applications:

• Coupling of a power-independent emergency drive to electric pumps
• Coupling of two redundant drive machines to one machine

history

The first commercial application of a self-synchronizing clutch was in the COSAG drive of the county class destroyers of the British Navy at the end of the 1950s. In 1964 the clutch was used for the first time in power plants so that a gas turbine generator could work in phase shifter mode. In 1978 the most powerful SSS coupling was put into operation in the Huntorf power plant , which can transmit an output of 300 MW.

literature

• M. Klocke, St. Kulig, G. Zimmer: Modeling and simulation of a self-synchronizing clutch in single-shaft systems . In: Electro-mechanical drive systems: innovations, trends, mechatronics; Conference proceedings; October 6-7, 2004 in Fulda . 2004, ISBN 978-3-8007-2852-7 , pp. 50-55 ( Google Book ).

Web links

• Patent AT206234 : Self- shifting synchronous clutch . Published November 10, 1959. Inventor: Harold Sinclair, SSS Gears Ltd.
• Patent US2986249 : Synchronous self-shifting clutches (SSS). Published April 30, 1961. Inventor: Arthur Clements, SSS Gears Ltd.
• Patent CH390007 : Self- engaging synchronous tooth clutch . Published on November 19, 1964 , inventor: Hans Sigg, Maag Zahnräder & Maschinen AG. ‌
• SSS Clutch engagement during high speed rotation. SSS Gears Ltd., February 8, 2010, accessed September 13, 2015 (video showing how the clutch works at high speed). 
• RENK-MAAG MS Synchronous Clutch Coupling. RENK-MAAG GmbH, accessed on September 15, 2015 (English). 

Individual evidence

1. ↑ How it works. SSS Gears Limited, accessed March 19, 2019 . 
2. ^ SSS Clutch Operating Principle. (No longer available online.) SSS Gears Limited, archived from the original on December 29, 2016 ; Retrieved September 15, 2015 (English, 2nd page, 2nd column, 3rd section). Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  
3. ↑ About SSS - History. In: www.sssclutch.com. Retrieved September 16, 2015 .