INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS
You can find more information on our web, so please take a look.
Log In
Are you an
Engineering professional?
Join Eng-Tips Forums!
*Eng-Tips's functionality depends on members receiving . By joining you are opting in to receive .
Promoting, selling, recruiting, coursework and thesis posting is forbidden.
Eng-Tips Posting Policies
Cardan shafts problem
thread384- Forum Search FAQs Links MVPsForum
Search
FAQs
Links
MVPs
(Industrial)
(OP)
29 Nov 21 15:14Hello to everyone,i have really strange case about cardan shaft problems.I attachment you find some photos about one of the cardan shaft failured.This is paper mill company and have big trouble during last year. All motors are DC motors with one AC/DC drive per unit motor.Some indications for you:Customer assumes that this problem may derive either from eddy currents or from the fact that a 4MW cogeneration unit was installed in the last year.What your opinion?
Replies continue below
(Electrical)
29 Nov 21 20:00I don&#;t work with cardan shafts at all. But my understanding is the arms of that cross form the inner race of needle bearings that oscillate position (don't continue rotating through their full range like normal bearings). One of the photos (below) presents a distinct pattern where the damage is heavier on one end of the inner race than the other. For a simple needle bearing, that type of observation would suggest to me a cause of excessive misalignment&#; but I&#;m not sure if the same conclusion holds for cardan shaft bearings.In terms of what changed the two captain-obvious uninformed swags would seem to be alignment (maybe a different guy at the same company) or parts (maybe inner ring material is more susceptible to fatigue).Again I have zero cardan shaft experience to go with that. I&#;m sure someone else can provide more insight.=====================================(2B)+(2B)' ?
(Mechanical)
29 Nov 21 21:03Sorry can&#;t open the attachment because it&#;s a zip file can you make a pdf please?
&#;Do not worry about your problems with mathematics, I assure you mine are far greater.&#; Albert Einstein
(Automotive)
29 Nov 21 21:31False brinelling may be an issue. That's caused by insufficient angles, the needles bounce on the inner and pump all the grease out.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
(Electrical)
29 Nov 21 22:42Quote (Pruftechnik)
The spacer shaft is set at a minimum angle of usually 4° to 6° in order to ensure sufficient lubricant circulation, which in turn prevents the universal joints from seizing
I didn't realize there was a minimum misalignment for cardan shaft / universal joints, but it makes sense and seems supported by this blurb which includes a thumbrule (undoubtedly the manufacturer's recommendation is more relevant):=====================================(2B)+(2B)' ?
(Automotive)
29 Nov 21 23:15You'd want at least half a rotation of the needle roller per rev of the shaft. Vibration and poor lube are risk factors. Also, one might find that a vendor has changed manufacturing plants and the new factory doesn't actually replicate the quality of the old one. Ahem.CheersGreg LocockNew here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies
(Electrical)
30 Nov 21 13:38Great info by Greg, as usual.> Sorry can&#;t open the attachment because it&#;s a zip file can you make a pdf please?attached.=====================================(2B)+(2B)' ?
(Mechanical)
30 Nov 21 17:26Are you saying there have recently been multiple cases of u-joints with this same damage?
What is the brand name on the Cardan joints? Both old reliables, and recent troublemakers.
It looks like those 3 or 4 needles were edge loaded pretty badly.
I suspect (but do not know for sure) that needles in good quality cardan joints are very slightly crowned ( a few µm / .s inch) to make them WAY more tolerant of small misalignments between joint cross journals and cups.
I picture a few things might cause such damage.
1 - Missing needles. There should be a full complement, with no room for more. ( assembly error, manufacturing error )
2 - Poor ID OD concentricity of the Bearing cups. (Poor quality manufacturing)
3 - Bent or poorly machined Cardan cross
4 - Bent or improperly machined yoke ears. Damaged yoke ear bores. (beyond the control of the Cardan joint manufacturer)
5 - IMMENSE torque overload (But I'd still expect more even full length needle loading, and one side of each of the 4 journals on each Cardan to show indications.)
Investigating all those 100% would keep me busy for a while.
A dial indicator for 2
V-blocks and a dial indicator for 3.
A precision pin several inches long for 4.
(Mechanical)
30 Nov 21 17:34Hi electricpeteThanks very much for the PDF &#;&#;
&#;Do not worry about your problems with mathematics, I assure you mine are far greater.&#; Albert Einstein
If you are looking for more details, kindly visit jundi.
(Industrial)
(OP)
6 Dec 21 10:57Thank you electripete for the PDF.
Unfortunately i tried to attach photos directly on the message but lot of error appear ...
@greglocock
This is exactly my idea for lot of reasons.
If nothing is cahged for years and only in this period is changed i'm afarid that vendor could be changed manufacturer and new cardan shaft quality is changed.
@Tmoose
thank you for the very detailed information, i'll go to check them and lot of them seems to be related to manufacturing quality and /or assembly error.. this is strictly related about info of Greglocock
Other than mechanical evident failures, what left me puzzled is the fact that it is happening in all the cardans at the same time while all the other surrounding conditions have not changed ..... I think, but I can be wrong, that the obvious cause of the damage is only the effect of a more structured problem
i'm going to verify alignment of some of the cardan shafts, i'm going to verify if nothing is changed on the motor control finding some tips can reveal the righ way to follow
(Marine/Ocean)
24 Dec 21 05:27That looks a lot like spalling to me. I have seen it caused by fatigue and I have seen it caused by hard impacts.I would expect to see fretting corrosion type wear if it were a lack of oscillation. Do you see corrosion products in the lubricant?Is your phasing correct?
Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.
Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.
Click Here to join Eng-Tips and talk with other members! Already a Member? Login
Introduction
The Cardan shaft, also known as a driveshaft or propeller shaft, is a critical component in many mechanical systems, most notably in the automotive and industrial sectors. It is responsible for transmitting torque and rotation from the engine to the wheels in vehicles, or between different parts of machinery. Understanding the Cardan shaft, its components, function, and applications, is essential for anyone involved in engineering, mechanics, or automotive technology. This comprehensive guide will take you through the basics and dive into more detailed aspects of the Cardan shaft.
History and Evolution
The Cardan shaft is named after the Italian mathematician Gerolamo Cardano, who conceptualized the universal joint in the 16th century. However, it was Robert Hooke in the 17th century who developed the universal joint further into what we recognize today. Over the years, the design and materials have evolved significantly, leading to more efficient, durable, and versatile Cardan shafts that can handle higher loads and operate in diverse conditions.
Working Principle
At its core, a Cardan shaft transmits torque and rotation through a series of components. The universal joints (U-joints) at either end of the shaft accommodate the changes in angle between the driving and driven components, allowing for smooth transmission of power even when the components are not perfectly aligned. This flexibility is crucial in applications where there is a need to accommodate movement and misalignment.
Key Components of a Cardan Shaft
1. Universal Joints (U-Joints): These are pivotal in allowing the shaft to transmit torque at various angles. They provide the necessary flexibility and can absorb minor misalignments between connected components.
2. Shaft Tubing: This is the main body of the Cardan shaft, typically made of steel, aluminum or composites for strength and durability. It transmits the torque from one end to the other.
3. Slip Yoke: This component allows for length compensation in the shaft, accommodating any changes in distance between the connected components due to movement or thermal expansion.
4. Flange Yoke: The flange yoke connects the shaft to other components, such as the transmission, shaft couplings or differential.
5. Balancing Weights: These are added to the shaft to ensure it is balanced during rotation, minimizing vibrations and wear.
6. Grease Fittings: These allow for regular lubrication of the U-joints, ensuring smooth operation and longevity.
7. Center Support Bearing: In longer shafts, this bearing provides additional support and stability, preventing excessive bending and vibration.
Common Applications
Automotive Industry: Cardan shafts are widely used in vehicles to transmit power from the engine to the wheels. This includes everything from cars and trucks to off-road vehicles.
Industrial Machinery: Many machines use Cardan shafts to transmit power between different parts, especially where flexibility and the ability to accommodate misalignment are crucial.
Marine Applications: Boats and ships often use Cardan shafts in their propulsion systems, where they need to handle variable angles and loads.
Aerospace Uses: Some aircraft systems also utilize Cardan shafts for power transmission, particularly in areas where flexibility and reliability are essential.
Maintenance and Troubleshooting
Regular maintenance is crucial for ensuring the longevity and performance of Cardan shafts. This includes:
Regular Inspection: Check for signs of wear, such as cracks, corrosion, or excessive play in the U-joints.
Lubrication: Ensure that grease fittings are regularly serviced to maintain smooth operation.
Balancing: Periodically check the balance of the shaft to prevent vibrations.
Alignment: Ensure that the shaft is properly aligned with the connected components to prevent undue stress and wear.
Common issues include excessive vibration, noise, and visible wear on components. Addressing these issues promptly can prevent further damage and costly repairs.
Innovations and Future Trends
Recent advancements in materials, such as carbon fiber, are leading to lighter and stronger Cardan shafts. Additionally, improvements in manufacturing techniques and design are resulting in more efficient and durable shafts. Future trends may include the integration of smart sensors to monitor the condition of the shaft in real time, allowing for predictive maintenance and improved reliability.
Conclusion
The Cardan shaft is a versatile and essential component in many mechanical systems, providing the flexibility and reliability needed to transmit power efficiently. From its historical origins to modern innovations, understanding the Cardan shaft is crucial for anyone involved in engineering or mechanics. Regular maintenance and staying informed about advancements can ensure these vital components continue to perform at their best.
Help and Support for your Cardan Shaft needs
For further information and or support for any kind of cardan shafts, check out METAL Mobility, they provide a broad range of expertise from within its driveshaft via global partners. Experienced cardan shaft specialists ensure a smooth running of your industrial, marine or automobile driveshafts.