Product category:
Gears, brakes, couplings and engines
News Release from: Mayr Transmissions | Subject: Slip Hub
Edited by the Engineeringtalk Editorial
Team on 08 November 2004
Torque limiter with integral control
device
Mayr has developed a torque limiter with the basic function of the ROBA - Slip Hub, together with an integral control device to limit the slip at a preset value.
Mayr has developed a torque limiter with the basic function of the ROBA - Slip Hub, together with an integral control device to limit the slip at a preset value Friction type torque limiters will actually slip over a wide variation of the pre-set overload torque due to changes in ambient conditions, wear and friction coefficient during the slipping process said Mayr
This article was originally published on Engineeringtalk on 7 Nov 2003 at 8.00am (UK)
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New concept in friction torque limiters
The Roba-clamp slip hub has been developed to meet today's requirements for an economical easy-to-fit torque limiter.
Torque limiters run up to 700Nm
Following customer demand from the wastewater and materials-handling industries, Mayr has expanded its EAS-HTL housed torque limiter range.
Mechanical clutches still outperform electronics
Although electronic overload devices may have improved, Mayer reckons that only mechanical torque-limiting clutches can provide extremely rapid and reliable overload protection.
During tests it was found that the coefficient of friction in a normal proprietary friction type torque limiter varied within a tolerance band of +/- 25 per cent, which resulted in unreliable torque transmission.
Mayr developed its new type of torque limiter to combine the advantages of both the friction and mechanical ball indent types of torque limiting clutch in a single unit.
The Controlled Slip Hub is a load holding friction torque limiter with an integral patented control device for precise torque limiting that controls any increase in coefficient of friction and torque transmission, even if the unit has not operated in a torque limiting function for some time claimed Mayr.
A test unit was set to run at 500rpm and slip for approximately 0.3 seconds at 185 Nm.
Over 10,000 slip/torque overload cycles resulted in an actual slipping torque of between 170 Nm and 200 Nm, a variation of +/- 15 Nm or +/- 8.1 per cent.
Further tests of 360 Nm torque at an identical speed and slipping time over 4000 torque overload cycles showed a variation of +/- 40 Nm or +/- 11.1 per cent.
For applications where a torque limiting function in combination with a load holding function is required - for instance, vertical machine tool slideways, access tables and hoists - the new development could be used.
The Controlled Slip Hub can be designed to suit customer specific requirements and applications.
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