|
'''Шарні́р рі́вних кутови́х швидкосте́й''' ('''гомокінетичний''' або '''РШ шарнір''') дозволяє валу обертання передавати [[обертальний момент]] під змінним у часі [[кут]]ом, з постійною [[частота обертання|частотою обертання]] й без суттєвих варіацій тертя. Загалом він використовується у [[передній привод|приводі передніх коліс]] та у [[повний привод|повному чотириколісному приводі]] [[автомобіль#Легкові автомобілі|легкових авто]]. [[автомобіль#Легкові автомобілі|Легковики]] з [[задній привод|приводом задніх коліс]] та з [[незалежна задня підвіска|незалежною задньою підвіскою]] загалом використовують РШ шарнір на кінцях півосей задньої передачі. Останнім часом їх також досить часто почали використовувати у з'єднаннях валу головної передачі. Легковик [[Audi quattro]] використовує ці шарніри для всіх 4х півосей і для [[карданний вал|карданного валу]] також, разом усього десять РШ шарнірів.
<!--
== Before the CV joint ==
Early front wheel drive systems such as those used on the [[Citroën]] [[Citroën Traction Avant|Traction Avant]] and the front axles of [[Land Rover]] and similar four wheel drive vehicles used [[universal joint]]s, where a cross-shaped metal pivot sits between two forked carriers. These are not CV joints as, except for specific configurations, they result in a variation of the transmitted speed. They are simple to make and can be tremendously strong, and are still used to provide a flexible coupling in some propshafts, where there is not very much movement. However, they become "notchy" and difficult to turn when operated at extreme angles, and need regular maintenance. They also need more complicated support bearings when used in drive axles, and could only be used in rigid axle designs.
== The first CV joints ==
As front wheel drive systems became more popular, with cars such as the [[Mini]] using compact transverse engine layouts, the shortcomings of Hookes joints in front axles became more and more apparent. Based on a design by [[Alfred H. Rzeppa]] which was filed for patent in 1927<ref name=patent>{{cite paper|url=http://v3.espacenet.com/origdoc?DB=EPODOC&IDX=US1665280&F=0&QPN=US1665280|author=Rzeppa, Alfred H.|title=Universal Joint|version=US patent no. 1,665,280|date=1927}}</ref> (a CV joint, the Tracta joint,<ref>[[Jean-Albert Grégoire|J-A Grégoire]]</ref> designed by Pierre Fenaille was filed for patent in 1926<ref>[http://v3.espacenet.com/publicationDetails/originalDocument?CC=FR&NR=628309A&KC=A&FT=D&date=19271021&DB=EPODOC&locale=fr_V3 European Patent FR628309]</ref>), constant velocity joints solved a lot of these problems. They allowed a smooth transfer of power despite the wide range of angles through which they were bent.
==Rzeppa joints==
[[Image:Cv joint large.png|thumb|right|300px|3D rendering of the internals of an Rzeppa CV joint]]
A Rzeppa joint consists of a spherical inner with 6 grooves in it, and a similar enveloping outer shell. Each groove guides one ball. The input shaft fits in the center of a large, steel, star-shaped "gear" that nests inside a circular cage. The cage is spherical but with ends open, and it typically has six openings around the perimeter. This cage and gear fit into a grooved cup that has a splined and threaded shaft attached to it. Six large steel balls sit inside the cup grooves and fit into the cage openings, nestled in the grooves of the star gear. The output shaft on the cup then runs through the wheel bearing and is secured by the axle nut. This joint is extremely flexible and can accommodate the large changes of angle when the front wheels are turned by the steering system; typical Rzeppa joints allow 45-48 degrees of articulation, while some can give 52 degrees. At the "outboard" end of the driveshaft a slightly different unit is used. The end of the driveshaft is [[Rotating spline|splined]] and fits into the outer "joint". It is typically held in place by a [[circlip]].
== Tripod joints==
These joints are used at the inboard end of car driveshafts. This joint has a three-pointed yoke attached to the shaft, which has barrel-shaped roller bearings on the ends. These fit into a cup with three matching grooves, attached to the [[Differential (mechanics)|differential]]. Since there is only significant movement in one axis, this simple arrangement works well. These also allow an axial 'plunge' movement of the shaft, so that engine rocking and other effects do not preload the bearings. A typical Tripod joint has up to 50 mm of plunge travel, and 26 degrees of angular articulation.<ref>http://www.gkndriveline.com/drivelinecms/export/sites/driveline/downloads/brochures/driveshafts_english.pdf</ref>
==Double Cardan==
Double Cardan joints are similar to [[Universal joint#Double Cardan Shaft|double Cardan shafts]], except that the length of the intermediate shaft is shortened as much as is practical, effectively allowing the two Hooke's joints to be mounted back to back. This provides true constant velocity operation at low speeds, but the torque required to accelerate the internals of the joint does provide some additional vibration at higher speeds. DCJs are typically used in steering columns, as they eliminate the need to correctly phase the universal joints at the ends of the intermediate shaft (IS), which eases packaging of the IS around the other components in the engine bay of the car. They are also used to replace Rzeppa style constant-velocity joints in applications where high articulation angles, or impulsive torque loads are common, such as the driveshafts and halfshafts of rugged four wheel drive vehicles. Double Cardan joints have been developed utilizing a floating centering element<ref>http://www.tpub.com/content/construction/14273/css/14273_181.htm</ref> to maintain equal angles between the driven and driving shafts.
==Thompson coupling==
The Thompson constant velocity joint (TCVJ), also known as a Thompson coupling, is a constant velocity [[universal joint]] that can be loaded axially and continue to maintain constant velocity over a range of input and output [[Drive shaft|shaft]] angles with low friction and vibration. It consists of two cardan joints assembled within each other, thus eliminating the intermediate shaft, along with a control yoke that geometrically constrains their alignment. The control yoke maintains equal joint angles between the input shafts and a relative phase angle of zero to ensure constant angular velocity at all input and output shaft angles. While the geometric configuration does not maintain constant velocity for the control yoke (aka intermediate coupling) that aligns the pair of cardan joints, the control yoke has minimal inertia and generates virtually no vibration. -->
<!-- Q: so why is the second joint needed then? A: To maintain the geometric alignment of the two cardan joints. -->
<!-- Eliminating the intermediate shaft and keeping the input shafts aligned in the homokinetic plane virtually eliminates the induced [[shear stress]]es and [[vibration]] inherent in traditional [[Universal_joint#Double Cardan Shaft|double cardan shafts]].<ref name = "Sopanen">{{cite web | url = http://www.ee.lut.fi/static/fi/lab/sahkokaytot/sameko/Cardan_Sameko.pdf | title = Studies on Torsion Vibration of a Double Cardan Joint Driveline | last = Sopanen | first = Jussi| date = 1996 | accessdate = 2008-01-22 }}</ref><ref name = "Sheu">{{cite web | url = http://cat.inist.fr/?aModele=afficheN&cpsidt=3004428 | title = Modelling and analysis of the Intermediate Shaft Between Two Universal Joints | last = Sheu | first = P| date = 2003-02-01 | accessdate = 2008-01-22 }}</ref>
The use of cardan joints within the Thompson Coupling also reduces the wear, heat and friction<ref name = "FKA">{{cite web | url = http://www.ika.rwth-aachen.de/pdf_eb/gb5-14e_cv_joint_efficiency.pdf | title = Measurement of CV Joint Efficiency | date = 2005-02-10 | accessdate = 2008-01-22 }}</ref> when compared with Rzeppa type constant velocity joints. Cardan joints, including Thompson couplings, utilise [[roller bearing]]s running [[circumference|circumferentially]], whereas Rzeppa constant velocity joints use balls which roll and slide axially along grooves.
The novel feature of the coupling is the method to geometrically constrain the pair of cardan joints within the assembly by using, for example, a spherical four bar scissors linkage and it is the first coupling to have this combination of properties.<ref name = "Bowman">{{cite web | url = http://www.centralwesterndaily.com.au/news/local/news/general/an-invention-to-drive-fuel-costs-down/191341.aspx | title = An invention to drive fuel costs down | publisher = yourguide.com.au | last = Bowman | first = Rebecca| date = 2006-08-03 | accessdate = 2007-02-13 }}</ref>
The coupling earned its inventor, Glenn Thompson, the [[Australian Society for Engineering in Agriculture]] Engineering Award.<ref name = "Filmer">{{cite web | url = http://www.centralwesterndaily.com.au/news/local/news/general/invention-generating-interest/360233.aspx | title = Invention generating interest | publisher = yourguide.com.au | last = Filmer | first = Mark | date = 2003-11-13 | accessdate = 2007-02-13}}</ref>
-->
== Див. також ==
== Джерела ==
{{reflist}}
{{без джерел}}
[[Категорія:Підвіска автомобіля]]
| 