Rotating and stationary shaft need to be engaged without slip

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SUMMARY

The discussion focuses on designing a mechanism to engage a rotating flywheel at 1000 RPM with a stationary shaft without slip. Participants recommend using a dog clutch for positive engagement, which locks the shafts together, ensuring no slip occurs. However, concerns about the dog clutch's effectiveness at higher speeds (2000 RPM) lead to alternative suggestions, including a Geneva mechanism and a hydraulic system utilizing a gear pump. The key requirement is to transfer approximately 9500J of energy within a fraction of a second, highlighting the need for precise specifications in the design.

PREREQUISITES
  • Understanding of clutch mechanisms, specifically dog clutches
  • Knowledge of hydraulic systems and gear pumps
  • Familiarity with energy transfer calculations and torque requirements
  • Basic principles of mechanical design and kinematics
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  • Research the design and application of dog clutches for high-speed operations
  • Explore the functionality and implementation of Geneva mechanisms in mechanical systems
  • Investigate hydraulic systems, focusing on gear pumps and their role in energy transfer
  • Learn about shear pins and their use in preventing premature movement in mechanical assemblies
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Mechanical engineers, designers of power transmission systems, and anyone involved in high-speed machinery requiring precise engagement mechanisms.

koolraj09
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Hi guys,
So here's one thing which I want to design and this thing involves a flywheel rotating at about 1000 rpm. I need to transfer this energy to another shaft which is stationary with a mechanism. The mechanism has to be actuated for only a second, and then disengaged. During engagement, the two shafts - driver and driven shaft have to be coupled but without slip (positive engagement as we call it).

Is there any mechanism by which I can do this?
Thanks
 
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A clutch.
 
Use a Clutch. It is meant for this purpose.
 
Clutches do have a limited amount of slip and if the engagement period is short, that might be material.
The OP does not give any guidance as to how much slip is acceptable, but it may be that he needs something else. He needs to specify his requirements more precisely.
 
Hi again.
Sorry if the requirements seemed incomplete. But what I do need is a positive drive without slip. The torque (& power) has to be transferred to driven shaft almost instantaneously (order of milliseconds or less to get full torque).
Also the input is continuously rotating while the output has intermittent (single or half revolution) motion.
Is there a specific device which does this?
 
I think you are looking for a device called a dog clutch. This has two interlocking pieces, and when activated the two shafts are locked together so they can't slip.
 
What is the final RPM? How much energy is transferred and how fast? Have you calculated the torque that generates?
 
Thanks phyzguy and Russ...
Dog clutch is actually a good suggestion...but from what I know is that dog clutch operate at low speeds...
The speeds that I want to operate the mechanism is roughly 2000 rpm. The energy involved is around (roughly) 9500J. This is the flywheel energy and flywheel speed. This speed would be geared down, but the this energy has to be transferred in a fraction of seconds..say 0.5 or 1 sec to the mechanism.
Any more suggestion, guys?
 
Sounds like a Geneva mechanism might work depending on how much you need the stationary shaft to rotate.
 
  • #10
You could use hydraulics. A gear pump on the flywheel could circulate fluid through a hydraulic motor attached to the shaft. A shunt between the two hydraulic lines would idle the system. When the shunt is blocked by a sliding spool valve, (for one second), the pump will couple directly to the motor.

If early shaft movement is a problem then a sacrificial shear pin through the shaft would prevent any rotation prior to complete obstruction of the shunt.

The gear pump on the flywheel could also be used as a motor to spin up the flywheel by using a constant pressure hydraulic power pack.
 

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