Replacing a centrifugal clutch with an Electromagnetic clutch

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Discussion Overview

The discussion revolves around the feasibility and methods of replacing a centrifugal clutch with an electromagnetic (EM) clutch in a CVT-driven two-wheeler. Participants explore the technical challenges, potential suppliers, and design considerations involved in implementing an electronically controlled clutch system.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about the existence of automobiles with EM clutches and expresses a need for a system that allows for power disconnection at will.
  • Another participant suggests that dual-clutch transmissions in high-end sports cars might provide insights into gradual engagement mechanisms.
  • Some participants propose contacting current suppliers for prototyping an electronically actuated version of the existing centrifugal clutch to facilitate integration.
  • Concerns are raised regarding the availability of suitable EM clutches, particularly for small-scale applications, with emphasis on the lack of suppliers in India focusing on automotive needs.
  • Participants discuss the torque requirements and the need for gradual engagement to avoid abrupt transmission changes, suggesting potential modifications to gearing or timing to achieve this.
  • Some participants mention the use of small EM clutches in applications like car air conditioning systems, questioning their applicability for the current project.
  • There are discussions about the dimensions and packaging constraints of the current system, with specific measurements provided for the available space.
  • One participant expresses skepticism about the cost and availability of small EM clutches suitable for two-wheeler applications.
  • A question is raised about the possibility of replacing the centrifugal clutch with a standard bike clutch that is electromagnetically actuated, seeking insights on how this could be achieved.

Areas of Agreement / Disagreement

Participants express a range of views on the feasibility of finding suitable EM clutches and the methods for achieving gradual engagement. There is no consensus on the best approach or the availability of appropriate components, indicating ongoing uncertainty and exploration of ideas.

Contextual Notes

Participants note limitations in supplier availability, particularly for small-scale manufacturing and prototyping. There are also unresolved questions regarding the specific torque requirements and the design modifications needed to accommodate an EM clutch in the existing system.

Who May Find This Useful

This discussion may be useful for automotive engineers, hobbyists interested in clutch systems, and those exploring the integration of electromagnetic components in two-wheeler applications.

CorvetteAB
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Hello friends,

Anyone ever thought of, or tried, or has come across an automobile with an EM clutch, probably electronically controlled? We have a CVT driven 2 wheeler with a centrifugal clutch, but we need to disconnect power at will (electronically), so an EM clutch was suggested. Anyone know how it can be done, and if there are any suppliers of EM clutches, preferably for automobiles?
We roughly have an idea of when the centrifugal clutch engages and drive is transmitted (a little less than 1000 rpm, but that can be calculated, not a problem). Our situation currently is that
1- we aren't sure on how to do it, as it might require complete redesign and manufacturing of the output shaft. We know how much space is taken up by the centrifugal clutch, and the space between that and the secondary pulley of the CVT, but since we don't know of any EM clutches of any suppliers, we aren't able to carry forward with any designs.
2- A Centrifugal clutch engages, more or less, gradually, so as to avoid jerk in transmission. We need to replicate that as much as possible, probably by varying the current supplied over a range to allow for engaging as the field reaches maximum engaging field. Anybody has any idea?

Awaiting a positive reply,
Thank you
 
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Don't the current dual-clutch transmissions found mostly in high-end sports cars use electronically controlled clutches? They must have some kind of gradual takeup to allow taking off from a standing start. You didn't say what your power-handling requirements were, but that might be a start.
 
Have you talked to your current supplier about prototyping an electronically actuated version of the current-production centripetal clutch? To me, that would be the easiest way to integrate this technology into a pre-existing system. You could keep what you know to work well, and add what you want.

How much torque do you need to transmit? What sort of life expectancy and duty cycle? There are a number of options that could possibly work, or be learned from.
 
sandy stone said:
Don't the current dual-clutch transmissions found mostly in high-end sports cars use electronically controlled clutches? They must have some kind of gradual takeup to allow taking off from a standing start. You didn't say what your power-handling requirements were, but that might be a start.

Well, it is run by a 110cc engine producing 7.88hp and 8Nm torque.
DCTs are waaay out of our league. We need a CVT-grade, scooter need EM clutch.
 
RogueOne said:
Have you talked to your current supplier about prototyping an electronically actuated version of the current-production centripetal clutch? To me, that would be the easiest way to integrate this technology into a pre-existing system. You could keep what you know to work well, and add what you want.

How much torque do you need to transmit? What sort of life expectancy and duty cycle? There are a number of options that could possibly work, or be learned from.
Thats the thing. All the suppliers we know, and the ones in India focus primarily on Machine tool EM clutches, and they don't do single part manufacturing or prototyping. They only undertake bulk orders, for mass production, say. So we would have to design from scratch, and neither do we have the time, nor would anybody manufacture that.
That's why, we are looking at existing small sized clutches, even abroad that could fit, but aren't able to find any.
 
I think small ones are used to connect car air conditioning pumps to the engine belt.
 
Finding an EM clutch that can handle your torque demands will not be difficult. They are common, proven, and inexpensive.

What are your packaging constraints? Maximum diameter and maximum height of current clutch?

As far as the engagement of the clutch is concerned, I don't know exactly what to suggest. Is there any possible alternative that can be used to mitigate the harshness caused by a more abrupt clutch engagement? Could you change the gearing for that range of RPM to provide a soft start? Retard the timing during engagement so that the power is not sudden and uncontrollable? etcetc
 
Tom.G said:
Here in the USA, a Google search finds 97 000 hits.
https://www.google.com/?gws_rd=ssl#q=electromagnetic+clutch+supplier+in+india

Catalog search gives 33 000 hits.
https://www.google.com/?gws_rd=ssl#q=electromagnetic+clutch+catalogue

One picked at random: https://ogura-clutch.com/downloads/ogura-industrial-products.pdf

Thanks.
One thing to be noted here is that ALL those are machine tool EM clutches. You can make out by the key way in the hole- you don't get such shafts inside a CVT.
We did come across that catalog when searching. The fact that it doesn't fit automotive applications is a reason for elimination. The other being overall space required- too wide.
 
  • #10
CWatters said:
I think small ones are used to connect car air conditioning pumps to the engine belt.
Are they? Haven't found any so far. Worth checking. Thanks for the info.
 
  • #11
RogueOne said:
Finding an EM clutch that can handle your torque demands will not be difficult. They are common, proven, and inexpensive.

What are your packaging constraints? Maximum diameter and maximum height of current clutch?

As far as the engagement of the clutch is concerned, I don't know exactly what to suggest. Is there any possible alternative that can be used to mitigate the harshness caused by a more abrupt clutch engagement? Could you change the gearing for that range of RPM to provide a soft start? Retard the timing during engagement so that the power is not sudden and uncontrollable? etcetc

It has been remarkably difficult, given that we have no suppliers here, and budget constraints limits us to India, as of now.
Common? In terms of car use, maybe. IN terms of 2 wheeler use- none found so far. Proven? Definitely. Inexpensive? Really? Not sure. What would a small one of 12 inch diameter cost? Do you know any good suppliers in and around where you stay?
Packaging constraints- the CVT. Around 1 inch. Thats all the shaft space that we have, with a max diameter of 120mm.
If we can find one with a catalog and at a good price, we can work our way in controlling it.
 
  • #14
Anyone know whether that centrifugal clutch can be replaced by a normal bike clutch, but electromagnetically actuated? If so, how would one do it?
 

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