Patent Application
20170234153
The present disclosure relates generally to turbochargers, and more particularly to vane levers for such turbochargers.
Some turbo machines such as, but not limited to, automobiles, trucks, aircraft, locomotives, ships, and auxiliary power generators, utilize a turbocharger, which may increase the internal combustion engine efficiency and power output of such turbo machines. The turbocharger, being a turbine-driven device, may achieve this by forcing extra air into the combustion chamber of the engine. For example, exhaust gas from the engine may drive the turbine of the turbocharger to drive an impeller of the compressor, which may draw in ambient air, compress the air, and then supply this extra air to the engine. In this manner, the engine may have improved fuel economy, reduced emissions, and higher power and torque.
Some turbochargers, such as variable turbine geometry turbocharges, utilize adjustable guide vanes to regulate the gas flow leading to the turbine wheel. For example, the adjustable guide vanes may be pivotable between an upper vane ring and a lower vane ring and be mechanically engaged with an adjustment ring via a plurality of vane levers. The adjustment ring may be actuated to rotate with respect to the upper vane ring such that the rotation of the adjustment ring engages the plurality of vane levers to simultaneously pivot all of the adjustable guide vanes between a closed position and an open position.
In some designs, the adjustment ring may experience axial movement due to clearances between the adjustment ring and the plurality of vane levers. In an effort to reduce axial movement of the adjustment ring, some turbochargers have employed stationary axial stops such as, for example, standoff pins threaded into the bearing housing and machined pads on the bearing housing. While effective, the interface between the adjustment ring and such stationary axial stops may experience undesired wear as the adjustment ring may operationally rotate against the stationary axial stops.
Another example may be found in U.S. Patent Application Publication No. 2011/0171009, which discloses a variable-vane assembly having a unison ring restrained axially by axial stops. The axial stops include a cap formed at an end of a cylindrical pin section. The cap includes a first diameter that is greater than a second diameter of the cylindrical pin such that the inner edge of the unison ring engages the cylindrical pin acting as a radial stop for the unison ring. In this arrangement, the unison ring is also axially positioned between the nozzle ring and the cap such that the cap prevents excessive axial movement of the unison ring away from the nozzle ring. While effective, the unison ring may be in continuous engagement with the cylindrical pin and the cap during operational rotation of the unison ring causing frictional wear at the contact area of these components.
In accordance with an aspect of the disclosure, a guide apparatus for a turbocharger is provided. The guide apparatus may include a lower vane ring offset axially from an upper vane ring. A plurality of vanes may be disposed between and pivotally coupled to the upper vane ring and the lower vane ring. An adjustment ring may include a plurality of apertures and may be in mechanical association with the plurality of vanes. A plurality of vane levers may be coupled to the plurality of vanes and may be received correspondingly by the plurality of apertures. Each vane lever of the plurality of vane levers may include a protuberance facing the adjustment ring. The protuberance may be capable of limiting axial movement of the adjustment ring.
In accordance with another aspect of the disclosure, a turbocharger is provided. The turbocharger may include a turbine housing and a bearing housing disposed between the turbine housing and a compressor housing. An upper vane ring may be secured in the turbine housing and may be proximate to the bearing housing. A lower vane ring may be offset axially from the upper vane ring. A plurality of vanes may be disposed between and pivotally coupled to the upper vane ring and the lower vane ring. An adjustment ring may be in mechanical association with the plurality of vanes. A vane lever may be coupled to one vane of the plurality of vanes and may include an arm in mechanical association with the adjustment ring. The vane lever may include a protuberance facing the adjustment. The protuberance may be contactable with the adjustment ring to limit axial movement thereof.
In accordance with yet another aspect of the disclosure, a vane lever for a guide apparatus of a turbocharger may include a base. The base may include a bore disposed therethrough. An arm may extend from the base and may be receivable in an aperture of an adjustment ring of the guide apparatus. A protuberance may extend from the base and may be capable of limiting axial movement of the adjustment ring.
These and other aspects and features of the present disclosure may be better appreciated by reference to the following detailed description and accompanying drawings.
It should be understood that the drawings are not to scale, and that the disclosed embodiments are illustrated only diagrammatically and in partial views. It should also be understood that this disclosure is not limited to the particular embodiments illustrated herein.
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The guide apparatus 28 may include a lever clearance 56 between the adjustment ring 40 and each protuberance 52 of the plurality of vane levers 46 and may include a ring clearance 58 between the adjustment ring 40 and the shoulder 54 of the upper vane ring 30. While the lever clearance 56 and the ring clearance 58 may allow for minor axial movement of the adjustment ring 40 between the shoulder 54 of the upper vane ring 30 and the plurality of vane levers 46, the protuberance 52 on each vane lever of the plurality of vane levers 46 serves as an axial stop against the adjustment ring 40.
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While each vane lever of the plurality of vane levers 46 is described to include a protuberance 52, in alternative embodiments, a single one of the vane levers 46 may include the protuberance 52, alternating vane levers 46 may include the protuberance 52, or any other combination of vane levers 46 may include the protuberance 52.
Based on the foregoing, it can be seen that the present disclosure can find applicability in many industries such as but not limited to those employing an internal combustion engine in various turbo machines such as, but not limited to, automobiles, trucks, aircraft, locomotives, ships, and auxiliary power generators. Through the novel teachings set forth above, the guide apparatus 28 may provide a protuberance 52 on at least one vane lever of the plurality of vane levers 46 to limit axial movement of the adjustment ring 40 such that the protuberance 52 and the adjustment ring 40 may rotate in unison with each other. In this manner, because the protuberance 52 rotates along with the adjustment ring 40, minimal sliding and rotational relative motion is present therebetween, which may be an advantage over other designs employing stationary axial stops that may cause wear due to the adjustment ring operationally rotating against the stationary axial stops. Moreover, the present disclosure may eliminate press fit manufacturing variations, which may be found in other designs. Furthermore, through the novel teachings set forth above, each vane lever of the plurality of vane levers 46 may be integrally manufactured with a protuberance 52 by any process well known in the industry such as, but not limited to, metal injection molding, casting, stamping, and fine blanking, thereby realizing a reduction of overall parts in the guide apparatus 28, and in turn, a reduction in costs.
In operation of the turbocharger 10, the plurality of vanes 36 of the guide apparatus 28 may be selectively adjusted to change the airflow passing to the turbine wheel 22 of the turbocharger 10. The plurality of vanes 36 may be adjusted, between an open position and a closed position, via selective actuation of the adjustment ring 40. For example, the adjustment ring 40 may be actuated to rotate, with respect to the upper vane ring 30, and, in turn, engage the plurality of vane levers 46 to also rotate thereby transmitting simultaneous pivotal movement to each vane of the plurality of vanes 36.
During operation of the turbocharger 10, the adjustment ring 40 may experience minor axial movement, which, however, may be limited as a result of the adjustment ring 40 abutting against the protuberance 50 of each vane lever of the plurality of vane levers 46. As such, the protuberance 50 of each vane lever of the plurality of vane levers 46 may serve as an axial stop to limit the axial movement of the adjustment ring 40. Moreover, because the protuberance 50 of each vane lever of the plurality of vane levers 46 rotates along with the adjustment ring 40, the relative motion, and in turn the amount of wear, therebetween may be minimal.
