Variable vane assembly for a turbocharger
Patent Information
- Application Number
- PCT/US2026/020068
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-21
- Filing Date
- 2026-03-20
- Publication Date
- 2026-09-24
Smart Images
Figure US2026020068_24092026_PF_FP_ABST
Abstract
Description
[0001] GAR 001535 IA - 1 - Variable-vane assembly for a turbocharger and turbocharger
[0002] Specification:
[0003] The invention relates to a variable-vane assembly for a turbocharger and to a turbocharger.
[0004] Turbochargers are essential components in modern internal combustion engines, designed to increase the efficiency and power output by forcing extra air into the combustion chamber. They are widely used in automotive, marine, and industrial applications, where enhanced engine performance is a critical requirement. A turbocharger commonly comprises a compressor wheel and a turbine wheel, which are connected via a common axle. In order to allow for better control over the amount of boost provided by the turbocharger, variable-geometry turbochargers have been developed. One kind of such variable-geometry turbochargers is a variable-vane turbocharger, which comprises a variable-vane assembly as is described in EP 2 171 220 B1.
[0005] The variable-vane assembly described in EP 2 171 220 B1 includes a nozzle ring with first and second apertures, a plurality of vanes each with an axle, vane arms affixed to the axles, and an adjustment ring, which is designated as a unison ring. The unison ring has recesses for receiving the free ends of the vane arms and is rotatable about the axis of the nozzle ring to pivot the vanes in unison. The assembly also includes radial-axial guide pins for the unison ring, which are inserted into the first apertures in the nozzle ring and rigidly affixed therein. The guide pins are non-rotatably secured to the nozzle ring and each guide pin defines a groove in its outer surface for receiving the radially inner edge of the unison ring. This design restrains the unison ring against excessive movement in both radial and axial directions.
[0006] These kinds of variable-vane assemblies are composed of numerous components, some of which are made from expensive materials. This drives up the cost of the assembly, because each assembly step necessitates the partsGAR 001535 IA - 2 -included in the assembly step to be manufactured at a certain tolerance level. Additionally, some of these components, even those made from special materials, are subject to wear over time due to friction, which can lead to degradation in the performance of the turbocharger.
[0007] It is an objective of the present invention to provide a cost-effective and durable variable-vane assembly for a turbocharger, which simplifies the assembly process, reduces the number of components, and enhances the performance and longevity of the assembly.
[0008] This objective is being met according to the present invention by providing a variable-vane assembly with the features according to claim 1, and a turbocharger with the features according to claim 8. Further advantageous embodiments are described in the dependent claims.
[0009] According to the invention, a variable-vane assembly for a turbocharger is provided. The assembly comprises a nozzle ring that encircles an axis and has a first surface and a second surface. Each surface extends in a radial direction with respect to the axis. In particular, the axis is along the common axle of the turbocharger that connects the compressor wheel and the turbine wheel.
[0010] The assembly also includes a plurality of vanes, each having an axle. The axles of the vanes are circumferentially distributed on the nozzle ring such that each vane is connected with the nozzle ring and positioned on the second surface. Each vane is rotatable about its respective axle, which extends through the nozzle ring to the first surface. In particular, the axles may be aligned parallel to the common axle. The axles may in particular be aligned perpendicular to the first surface and / or to the second surface. Advantageously, the vanes are located at an inlet for motor exhaust to the turbine wheel, such that their orientation determines the amount of exhaust entering the turbine.
[0011] The assembly further includes a plurality of vane arms positioned on the first surface. Each vane arm is affixed to a respective axle of a respective vane andGAR 001535 IA - 3 -has a free end. An adjustment ring is also included in the assembly. The adjustment ring has a radially inner edge and is positioned coaxially with the nozzle ring and adjacent to the first surface of the nozzle ring. The adjustment ring is connected to the free ends of the vane arms. The adjustment ring is rotatable about the axis of the nozzle ring, so as to pivot the vane arms, thereby pivoting the vanes in unison. Such an adjustment ring is therefore often called a unison ring.
[0012] The assembly also includes a plurality of guide bosses that protrude axially from the first surface. Each guide boss defines or comprises a guiding groove that has a guiding surface facing the adjustment ring. The guiding groove is designed for receiving the radially inner edge of the adjustment ring. This arrangement is designed such that the adjustment ring is restrained by the guide boss against excessive movement in the radial and / or axial direction.
[0013] A key feature of the present invention is that the guide bosses and the nozzle ring form a one-piece construction. This one-piece construction provides a robust and reliable assembly that can withstand forces applied to it during rotation of the adjustment ring. The one-piece construction also simplifies the assembly process and reduces the number of separate components, thereby reducing manufacturing costs. Furthermore, the one-piece construction eliminates the need for separate connections to secure the guide bosses to the nozzle ring, thereby reducing the risk of failure due to loosening or breakage of such connections. The one-piece construction also provides a smooth and continuous surface, thus reducing buildup of dirt, which might otherwise necessitate maintenance.
[0014] The one-piece construction formed by the guide bosses and the nozzle ring in particular means that the guide bosses and the nozzle ring are formed in a monolithic construction. In other words, the guide bosses and the nozzle ring are made in form of a single, unified structure that is formed from one piece of material, rather than assembled from multiple separate components. In particular, they may be machined from a single billet, resulting in a unifiedGGAR 001535 IA - 4 -structure with no seams or joints. Advantageously, the guide bosses and the nozzle ring are integrally machined in a single, continuous process.
[0015] According to an advantageous embodiment, the guiding surface of each guide boss and the surface of the adjustment ring form an area contact. This means that the contact between the guide boss and the adjustment ring is not merely a point or line contact, but rather that the guide boss and the adjustment ring touch along a two-dimensional surface area of each. This area contact has the effect that the forces and torques between the guide boss and the adjustment ring are distributed along a larger surface portion, thus lowering the forces per surface area, leading to a lower amount of friction. The area contact can also reduce wear and tear on the contact surfaces, thereby extending the lifespan of the assembly. Furthermore, the area contact can provide a smoother and more precise adjustment of the vanes, as the adjustment ring can slide more smoothly and evenly over the guiding surfaces of the guide bosses. This can improve the performance and efficiency of the turbocharger.
[0016] One way of distinguishing an area contact from a line contact may be that a line contact as a two-dimensional feature extends in one of the dimensions by an order of magnitude or more larger than in the other dimension, while, in contrast, the area contact extends in both dimensions by the same order of magnitude.
[0017] The area contact can be achieved by appropriate shaping of the guiding surfaces and the surface of the adjustment ring. The guiding surfaces and the surface of the adjustment ring at the position of the guiding surfaces can be curved in different shapes, as long as they are shaped to conform to each other and create an area contact when the adjustment ring is in its operational position. The guiding surfaces and the surface of the adjustment ring can be machined or otherwise processed to achieve the desired shape and smoothness. The area contact can also be facilitated by the use of suitable materials for the guide bosses and the adjustment ring, such as materials with good wear resistance and low friction coefficients.GAR G001535 IA - 5 -
[0018] In another aspect of the invention, each guiding surface and the surface of the adjustment ring adjacent to that guiding surface have substantially a same radius of curvature in a plane perpendicular to the axis. This means that the guiding surfaces of the guide bosses and the corresponding surface of the adjustment ring are shaped to match each other closely, thereby ensuring a good fit and a smooth, even contact between these surfaces. This can improve the stability and precision of the adjustment of the vanes, as the adjustment ring can slide smoothly and evenly over the guiding surfaces of the guide bosses. This can also reduce wear and tear on the contact surfaces, thereby extending the lifespan of the assembly. The radius of curvature of the guiding surfaces and the corresponding surfaces of the adjustment ring can be determined based on the desired performance characteristics of the turbocharger, such as the required range of adjustment of the vanes, the desired speed and smoothness of the adjustment, and the expected operating conditions of the turbocharger.
[0019] The guiding surface and the surface of the adjustment ring adjacent to that guiding surface touch at the area contact. In a plane that is parallel to the first surface and crosses the area contact, the guiding surface defines a first curve and the surface of the adjustment ring adjacent to that guiding surface defines a second curve. Advantageously, the first curve has a first derivative that equals a first derivative of the second curve around the area contact. More advantageously, the first curve has also a second derivative that equals a second derivative of the second curve around the area contact.
[0020] Advantageously, the assembly includes one or more guide boss pairs. Each guide boss pair consists of two guide bosses, each of which is located along an azimuthal direction on either side of one of the vane arms on the first surface. In other words, along the azimuthal direction one may encounter a first guide boss of the pair, then the vane arm and then the second guide boss of the pair. The assembly may advantageously comprise three, four, five or six such guide boss pairs distributed along the perimeter of the first surface. By positioning aGAR 001535 IA - 6 -pair of guide bosses on either side of a vane arm, the adjustment ring is more securely guided and restrained against excessive movement in the radial and / or axial direction. This can improve the performance and efficiency of the turbocharger by ensuring a more precise and stable adjustment of the vanes. The guide boss pairs can be evenly distributed around the circumference of the nozzle ring. The number of guide bosses may in particular be smaller than the number of vane arms. The guide bosses in each pair can be identical or different in size, and / or shape, depending on the specific requirements of the turbocharger design.
[0021] In a further preferred embodiment, each of the guide bosses has a crosssection that is substantially rectangular shaped along a plane parallel to the first surface. This rectangular shape provides a large contact area between the guide bosses and the adjustment ring, which can improve the stability and precision of the adjustment of the vanes. The rectangular shape can also simplify the manufacturing process, as it can be easily achieved by standard machining or molding techniques. The dimensions of the rectangular crosssection can be determined based on the specific requirements of the turbocharger design, such as the required range of adjustment of the vanes, the desired speed and smoothness of the adjustment, and the expected operating conditions of the turbocharger.
[0022] According to a preferred embodiment, the assembly includes a plurality of recesses distributed along the inner perimeter of the radially inner edge of the adjustment ring. This means in particular that the radius of the inner perimeter of the adjustment ring is larger at each recess than at positions away from the recess in azimuthal direction. Each recess is designed for respectively receiving the free ends of the vane arms. This design ensures that each vane arm is securely and precisely connected to the adjustment ring. The recesses can also provide a clear and straightforward visual indication of the positions of the vane arms, which can facilitate the assembly and maintenance of the turbocharger. The number and distribution of the recesses should preferably correspond to the number and distribution of the vane arms. TheGAR G001535 IA - 7 -shape and size of the recesses can be determined based on the shape and size of the free ends of the vane arms, to ensure a good fit and a smooth and even contact between these components.
[0023] In a further embodiment of the invention, the guide bosses and the recesses in the radially inner edge of the adjustment ring are configured and located such that in a first rotational position of the adjustment ring with respect to the nozzle ring, each of the guiding bosses is aligned with an associated one of the recesses in the inner edge of the adjustment ring. This alignment allows the adjustment ring to be slid axially past the guiding bosses into proximity with the first face of the nozzle ring. Once in this position, the adjustment ring can then be rotated into a second rotational position with respect to the nozzle ring in which one, multiple or all of the guiding bosses are misaligned with the recesses in the inner edge of the adjustment ring. In this second position, the adjustment ring is captured by the guiding bosses and is prevented from being axially withdrawn from the nozzle ring.
[0024] This configuration provides a secure and reliable means of attaching the adjustment ring to the nozzle ring, while still allowing for easy assembly and disassembly. The use of the guide bosses and recesses to capture the adjustment ring also eliminates the need for additional fasteners or other attachment means, simplifying the design and reducing the number of separate components. Such a bayonet mount assembly can reduce manufacturing costs and simplify maintenance.
[0025] According to a further aspect of the invention, a turbo charger comprising the variable-vane assembly is suggested. Any embodiments, features and / or advantages in connection with the variable-vane assembly described herein above or in the following may also apply accordingly to the turbo charger.
[0026] Some examples of embodiments of the present invention will be explained in more detail in the following description with reference to the accompanying schematic drawings, wherein:GAR G001535 IA - 8 -
[0027] Fig. 1 shows schematically a partial cross section of a section of a variablevane assembly according to one advantageous embodiment;
[0028] Fig. 2 shows a different partial cross section of the variable-vane assembly of Fig. 1;
[0029] Fig. 3 shows schematic of a perspective view from the top onto the first surface of the variable-vane assembly of Fig. 1, showing a pair of guide bosses;
[0030] Fig. 4 shows schematic of a perspective view from the top onto the first surface of the variable-vane assembly of Fig. 1, with the guide bosses shown in cross sectional view; and
[0031] Fig. 5 shows a plan view from the top onto the first surface on the variablevane assembly of Fig. 1.
[0032] Figs. 1-3 show different views on a variable-vane assembly according to a preferred embodiment. In Figs. 1 and 2, the variable-vane assembly is shown with a partial cross-section cut in a plane in which also lies a common axle 10 of the assembly, as shown in Fig. 2. As shown in Figs. 1 and 2, the assembly comprises a nozzle ring 1 having a first surface 11 and a second surface 12, which are parallel to each other, on opposite sides of the nozzle ring 1. On its second surface 12, the nozzle ring 1 is supporting vanes 4, which are tiltable to adjust a cross-section to an inlet to the turbine wheel. Each vane 4 is connected to a corresponding vane arm 5 by way of an axel 51, which is placed inside a through-hole through the nozzle ring 1. The vane arms 5 are located in the first surface 11 of the nozzle ring 1. Opposite to its axel 51 , each vane arm 5 has a free end 52, which is positioned inside a corresponding recess 25 in the adjustment ring 2. The recesses 25 are distributed along the inner edge 22 of the adjustment ring 2.
[0033] The cross-section in Fig. 1 is through a section of the nozzle ring 1 that supports a guide boss 3. As can be seen here, the guide boss 3 is a raised section or embossment on the first surface 11 of the nozzle ring 1. In particular, the guide boss 3 together with the body of the nozzle ring 1 areGAR G001535 IA - 9 -machined or otherwise manufactured from one single material piece, in particular from a metal piece. The guide boss 3 is placed near the outer perimeter of the nozzle ring 1 and comprises a guiding groove 31 at its outer edge, which is perpendicular to the first surface 11. The guiding groove 31 is designed to accommodate the adjustment ring 2 and has on its bottom a guiding surface 32, which is adjacent to the inner edge 22 of the adjustment ring 2. When the adjustment ring 2 is rotated around the common axel 10, the inner edge 22 of the adjustment ring 2 slides on the guiding surface 32 inside the guiding groove 31.
[0034] Fig. 2, on the other hand, shows a cross-section through a section of the nozzle ring 1 that is further away from the guide boss 3, but instead dissects one of the vanes 4. In this Fig. 2 an insert ring 6 is also visible. The insert ring 6 is located in a bore of the turbine housing and thus surrounds the turbine wheel, which is not shown in the figures. The vanes 4 are sandwiched between the insert ring 6 and the nozzle ring 1.
[0035] As can be seen both in Fig. 3 and even better in Fig. 2, not every space between two vane arms 5 is occupied with a guide boss 3. Instead, a pair of guide bosses 3 are placed on either side of one vane arm 5 (the vane arm 5 furthest to the left shown in Fig. 2 and the middle vane arm 5 shown in Fig. 3), while the other visible spaces are not occupied with a guide boss. Another feature that is visible in Fig. 3 is that the top parts of the guide bosses 3 have a width parallel to the first surface 11 that allows them to fit inside the recesses 25 in the adjustment ring 2. This allows a bayonet mount assembly such that the adjustment ring 2 is placed on the nozzle ring 1 by first aligning all guide bosses 5 to coincide with corresponding recesses 25 of the adjustment ring 2, and then rotating the adjustment ring 2 such that it is help by the guide bosses 3. In a second step, the vane arms 5 can be positioned on their respective axles 51 and fixed in place.
[0036] Fig. 4 shows the same variable-vane assembly in a similar perspective view as in Fig. 3. However, here a top section of the guide bosses 3 is cut along a planeGAR G001535 IA - 10 -parallel to the first surface 11. This allows for a better visibility of the way the guiding surface 32 inside the guide groove 31 of the guide boss 3 may be designed with respect to the surface of the inner edge 22 of adjustment ring 2. As can be seen, the curvature of the guiding surface 32 and of the inner edge 22 of adjustment ring 2 conform closely to each other over the entire arch length covered by the guide boss 3. This feature is also observable in Fig. 5, which shows the variable-vane assembly viewed from above when looking onto the first surface 1. As can be seen here, the guiding surface 32 has a curvature along the plane parallel to the first surface 1 that equals or closely resembles a curvature of the surface inner edge 22 of adjustment ring 2.GAR G001535 IA
[0037] - 11 - Reference list:
[0038] 1 nozzle ring
[0039] 10 common axle
[0040] 11 first surface
[0041] 12 second surface
[0042] 2 adjustment ring
[0043] 22 inner edge of adjustment ring
[0044] 25 recess
[0045] 3 guide boss
[0046] 31 guiding groove
[0047] 32 guiding surface
[0048] 4 vane
[0049] 5 vane arm
[0050] 51 axel
[0051] 52 free end of vane arm
[0052] 6 insert ring
Claims
GAR G001535 IA - 12 - Claims:
1. A variable-vane assembly for a turbocharger, comprising:- a nozzle ring (1 ) encircling an axis (10) and having a first surface (11 ) and a second surface (12), each surface (11, 12) extending in a radial direction with respect to the axis (10);- a plurality of vanes (4), each having an axle (51 ), the axles (51 ) being circumferentially distributed on the nozzle ring (1) such that each vane (4) is connected with the nozzle ring (1) and positioned on the second surface (12), rotatable about the respective axle (51), wherein the axles (51 ) extend through the nozzle ring (1 ) to the first surface (11);- a plurality of vane arms (5) positioned on the first surface (11), each vane arm (5) being affixed to a respective axle (51 ) of a respective vane (4) and having a free end (52);- an adjustment ring (2) having a radially inner edge (22) and being positioned coaxially with the nozzle ring (1 ) adjacent the first surface (11) thereof and connected to the free ends (52) of the vane arms (5), the adjustment ring (2) being rotatable about the axis of the nozzle ring (1 ) so as to pivot the vane arms (5), thereby pivoting the vanes (4) in unison; and- a plurality of guide bosses (3) protruding axially from the first surface (11), each defining a guiding groove (31) having a guiding surface (32) facing the adjustment ring (2), the guiding groove (31) being designed for receiving the radially inner edge (22) of the adjustment ring (2) such that the adjustment ring (2) is restrained by the boss (3) against excessive movement in radial and / or axial direction, characterized by that the guide bosses (3) and the nozzle ring (1 ) form a one-piece construction.
2. Assembly according to claim 1, characterized by that the guiding surface (32) of each guide boss (3) and the surface of the adjustment ring (2) form an area contact.GAR G001535 IA - 13 -3. Assembly according to claim 1 or 2, characterized by that each guiding surface (32) and the surface of the adjustment ring (2) adjacent to that guiding surface (32) have substantially a same radius of curvature in a plane perpendicular to the axis.
4. Assembly according to one of the previous claims, characterized by one or more guide boss pairs of two guide bosses (3), each arranged along an azimuthal direction on either side of one of the vane arms (5) on the first surface (11).
5. Assembly according to one of the previous claims, characterized by that along a plane parallel to the first surface (1 ), each of the guide bosses (3) has a cross-section that is substantially rectangular shaped.
6. Assembly according to one of the previous claims, characterized by a plurality of recesses (25) distributed along the inner perimeter of the radially inner edge (22) of the adjustment ring (2), each recess (25) designed for respectively receiving the free ends (52) of the vane arms (5).
7. Assembly according to claim 6, characterized by that the guide bosses (3) are configured and located and the recesses (25) in the radially inner edge (22) of the adjustment ring (2) are configured and located such that in a first rotational position of the adjustment ring (2) with respect to the nozzle ring (1) each of the guiding bosses (3) is aligned with an associated one of the recesses (25) in the inner edge (22) of the adjustment ring (2), thereby allowing the adjustment ring (2) to be slid axially past the guiding bosses (3) into proximity with the first face of the nozzle ring (1 ), the adjustment ring (2) then being rotatable into a second rotational position with respect to the nozzle ring (1) in which the guiding bosses (3) are misaligned with the recesses (25) in the inner edge (22) of the adjustment ring (2) such that the adjustment ring (2) is captured by the guidingGAR G001535 IA - 14 - bosses (3) and prevented from being axially withdrawn from the nozzle ring (1).
8. A turbo charger comprising the variable-vane assembly according to one of the previous claims.