Talk:Constant-velocity joint

This page should include an entry on the Thompson Coupling, a constant velocity variety of universal joint which, unlike the ball-bearing constant velocity joint, can withstand an axial load such as experienced by a helicopter prop. Unlike the Hooke's type universal joint which has a sinusoidal output, the Thompson coupling is a true constant velocity joint. Reference: cvcoupling.com - Simon Purser

This page should not (just) give so much background about the automotive application, this is just an application and this article is about the CV joint itself. It should first explain how the thing works. This does not get immediately clear from the pictures without detailed descriptions.

I don't know a single thing about this subject, but is listing a specific instance of implementation in the introduction paragraph good form? Digitalsushi 12:40, 29 May 2007 (UTC)

Last section
I believe the last section should not be removed (maybe revised, if you believe so). I took my car today to the mechanic, who after inspection told me that the following long list of things needed to be done. Knowing nothing about cars, I went to Wikipedia to find out what these meaningless jargon was about.

The last section was highly informative. It connected the subject of this article to a real-life experience (making noise when turning) in few simple words that helped me understand what the noise I have been hearing for months is, how vital this part is to the car, and what options I have.

While Wikipedia is unarguably not a do-it-yourself site, I believe that other than the technical part of the article, the last section provides information that is best reached in this article. —Preceding unsigned comment added by 83.83.234.195 (talk) 16:46, 2 April 2009 (UTC)

I think that the article should also include description of the double hookes joint, with centering ball, used in heavier vehicles as an alternative to Rzeppa. These were called Glasener-Spicer at one time, and are now made by Ital Cardano (Spicer Italy). The Timoney designed armoured vehicles use these usually. Also double hookes (without centering ball) are commonly used on the steering axles of military trucks. John Begg —Preceding unsigned comment added by 59.92.88.35 (talk) 06:52, 8 April 2009 (UTC)

cost
How much does a CV joint usually cost? Murakumo-Elite (talk) 17:41, 10 November 2009 (UTC)

It cost around INR 2000 User:Nilesh Desale

versus the U-joint
I thought that the U-joint handles angles in one plane well -- the example being the drive shaft of a rear wheel drive car -- but in front wheel drive, a u-joint would have to move in two planes (up/down for suspension, left/right for steering) and here it doesn't do so well
 * Um, no, the UJ just sees one angle, it doesn't understand up down vs left right, it just sees the sqrt(steer^2+bump^2) angle.

why are U-joints left open (uncovered) while CV joints are typically protected by a rubber boot? Feldercarb (talk) 22:46, 27 December 2009 (UTC)


 * UJs have individually sealed bearings, whereas CVs have large tracks that need sealing Greglocock (talk) 00:02, 28 December 2009 (UTC)

Clarify UJ
This article says about Universal Joints that 'they result in a variation of the transmitted speed'. That doesn't make sense to me. I'm guessing by 'speed' it means 'rotational velocity'. But there's no way the rotation can change - it's not a gear. Can someone clarify before I reword the sentence. Thanks. peterl (talk) 00:51, 13 July 2011 (UTC)


 * The rotational speed does vary during one revolution. So isuggest that any rewrite needs to clarify that. Greglocock (talk) 02:20, 13 July 2011 (UTC)


 * Ah yes, so the number of revolutions would be the same, but within one revolution there would be some variations. Thanks. peterl (talk) 06:31, 13 July 2011 (UTC)
 * This article is near-useless (maybe worse, in being actively misleading) because it fails completely to explain the problem that necessitated the development of the CV joint - this fact that a Hooke joint has this uneven translation of input rotation to output rotation. For a front-wheel drive car (i.e. transmission through some sort of UJ on a steering axle), this is a real problem. FWD cars can't use simple UJs here, unless they're a CV joint. A few older 4WD vehicles used Hooke joints in their front axles, but these were only suitable for relatively slow speeds, on a chassis that wasn't designed for easy handling anyway. Andy Dingley (talk) 11:24, 3 August 2011 (UTC)

Invented in the 1920s?
According to the Universal joint page, proposed by Hooke in 1683. T. Mazzei (talk) 08:31, 1 October 2011 (UTC)


 * I fixed this by adding a brief intro. Was reading a book about Cardano, which brought me here. linas (talk) 05:45, 27 March 2012 (UTC)

Comparison table
The article needs a means of comparing the various CV joint types. Perhaps a table with the following columns: name, invention data, complexity/cost, efficiency, degrees of freedom?, etc..--Hooperbloob (talk) 18:08, 19 June 2012 (UTC)

Good idea. I'd lose efficiency, it is very hard to measure because all CV joints are very efficient. Some claim to be very very efficient. I don't know how you'd compare cost for that matterGreglocock (talk) 01:50, 20 June 2012 (UTC)

Rear wheel drive cars increasingly come equipped with propshafts?
''Rear wheel drive cars with independent rear suspension typically use CV joints at the ends of the rear axle halfshafts, and increasingly use them on the propshafts.'' ..

Is global warming causing such rapid rises in sea levels that cars are being equipped with propshafts as a precautionary measure?

24.250.167.105 (talk) 20:18, 13 October 2012 (UTC)


 * Those aren't propshafts, they're driveshafts. "Propeller shafts" are a UK term for the longitudinal driveshaft to a rear axle (or front axle for 4WD) and they are found with independent suspension or beam axles. Andy Dingley (talk) 20:37, 13 October 2012 (UTC)

I am going to change "drive shafts" to "drive shaft" as there is typically one drive shaft and two half shafts involved and it will improve clarity. Unless, of course, someone needs to add a lot of verbosity to allow for 4*4s which have 2 drive shafts and 4 half shafts... — Preceding unsigned comment added by Tiger99 (talk • contribs) 18:17, 19 December 2019 (UTC)
 * I'd probably avoid drive shaft altogether, in favour of prop shaft, as too confusing.
 * Also (this may be a UK thing) "half shaft" isn't generally used except for rigid axles. But then, "drive shaft" brings the confusion back. Andy Dingley (talk) 18:48, 19 December 2019 (UTC)

Currently used CV joint?
So which type(s) are used in most front-wheel drives today? The article isn't very clear on this. --Joe Sewell (talk) 16:29, 27 March 2014 (UTC)
 * Rzeppa. Nearly everything uses one per shaft on the outboard, with the inboard end of the shaft often a simpler type. Andy Dingley (talk) 21:48, 27 March 2014 (UTC)


 * Some FWD used to use tripods on the inner joint (to give plunge), and of course some used to use rubber donuts. Not many cars use true Rzeppas, they tend to be a slightly modified geometry, I was told.Greglocock (talk) 22:50, 27 March 2014 (UTC)

I believe that the correct term is tripode, not tripod. You all know what a tripod looks like, I presume? 3 legs, not 3 roller bearings. Some one please confirm, if possible. Tiger99 (talk) 17:59, 19 December 2019 (UTC)

More pictures needed
Some of the sections don't have any pictures, and it is difficult to visualise from the verbal description. On the other hand, a few of the sections have excellent pictures that move, showing the actual function. WesT (talk) 19:17, 29 December 2014 (UTC)

The illustration of the revolving Rzeppa joint does not show the outer shell realistically. Instead of fingers there is a cup with grooves on the inside for the six balls. There is also a guide ring, not shown, which forces the balls to remain in a plane at half the angle between shafts. The ring has oval slots, one for each ball. The slots are oval because there is some small motion between the balls tangentially as they rotate. I do not recommend changing the illustration. I never rebuilt these shafts but have replaced several of them in front wheel drive cars. wd4nit@yahoo.com  2602:30A:C0C6:E140:C51:76A9:8778:47DC (talk) 02:49, 8 February 2016 (UTC)

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Lubricant
Everyone on various forums seems to get this wrong. The lubricant is NOT Molybdenum Disulphide (note spelling, these joints originated in Europe, not the USA, and the European spelling is appropriate). It is in fact called Molybentone because it contains TWO essentail ingredients, Molybdenum Disulphide and Bentonite. If you use normal Molybdenum Disulphide grease it centrifuges out of the working parts into the rubber gaiter and the joint fails quite quickly due to lack of lubrication. The Bentonite was introduced during the development of the early Mini, the first major use of Rzeppa joints in the automotive industry, in about 1958 and has been there since. Bentonite is water repellent and somewhat sticky.

Tiger99 (talk) 18:13, 19 December 2019 (UTC)

Rzeppa Joints
"Inboard" and "outboard" seem to be confused. The joint as described is at the outboard end, of necessity, as a large operating angle is needed to allow the steering to work. At the inboard end a slightly different, and sometimes not homokinetic, joint is used as the operating angle is small. I can't guess the intention of the last author(s), so I am going to have to leave it for someone else to fix. Typically the early inboard joints were an elastomeric Hooke joint plus sliding spline(e.g. original Mini, not homokinetic), plain Hooke joint (tuned models like Mini Cooper), Offset Sphere (different geometry to outboard joint, with plunge, homokinetic) (later Minis), doughnut (Triumph 13000), not homokinetic, or Tripode (various vehicles, often not perfectly homokinetic). Someone who knows what a wide range of modern vehicles use should have a look at this. My last several have used tripode joints.

Tiger99 (talk) 18:36, 19 December 2019 (UTC)