Adjustable guide vane for a turbine, turbine for an exhaust gas turbocharger and exhaust gas turbocharger

Abstract

Adjustable guide vane assembly for a turbine, comprising a bearing ring (2) with a plurality of guide vanes (3), wherein the guide vanes (3) are rotatably mounted on the bearing ring (2) by means of guide vane shafts (5), wherein an adjusting lever (6) is associated with the guide vane shaft (5) for positioning the guide vane (3), which is designed to engage in a rotatable rotating ring (7) of the adjustable guide vane assembly (1), and wherein the adjustable guide vane assembly (1) has a support ring (9) for mounting in an exhaust gas duct section of the turbine, and wherein the support ring (9) serves as a bearing for the rotating ring (7), wherein the rotating ring (7) is guided radially and / or axially by means of at least one guide element (14), wherein the guide element (14) is received on the support ring (9), characterized in that the guide element (14) is pin-shaped.

Description

[0001] The invention relates to an adjustable guide device for a turbine according to the preamble of claim 1, a turbine for an exhaust gas turbocharger according to claim 9 and an exhaust gas turbocharger according to claim 10.

[0002] Published patent application DE 10 2014 203 498 A1 discloses an adjustable guide vane for a turbine. With the aid of the adjustable guide vane, the flow of exhaust gases escaping from an internal combustion engine onto a turbine wheel housed in an exhaust gas guide section of the turbine can be conditioned. For this purpose, the guide vane has a number of adjustable guide vanes positioned in a nozzle channel in the exhaust gas guide section, upstream of a wheel chamber in the exhaust gas guide section in which the turbine wheel is rotatably received. The guide vane has a bearing ring with a plurality of guide vanes, wherein the guide vanes are rotatably mounted on the bearing ring by means of guide vane shafts. Adjusting levers designed to engage with a rotating ring are generally assigned to the guide vane shafts. The rotating ring has recesses for receiving the adjusting levers.

[0003] The rotating ring is designed like a ring disk and is supported radially and axially. Axial and radial support is provided by the bearing ring. To reduce friction, the rotating ring has recesses on its bearing surface opposite the bearing ring. This reduces surface contact between the rotating ring and the bearing ring, thus reducing frictional losses due to surface friction.

[0004] From the published patent application JP 2009 - 243 431 A, an adjustable guide device is also known, the rotating ring of which is guided radially and axially by means of at least one angled guide element, wherein the guide element is accommodated in abutting relation to a support ring.

[0005] The invention is based on the object of providing an adjustable guide vane characterized by a further reduction in friction losses, which can be achieved by means of simple measures. Furthermore, it is an object of the invention to provide a turbine with increased operational reliability and to design an exhaust gas turbocharger with significantly improved efficiency.

[0006] These objects are achieved by means of an adjustable guide vane for a turbine having the features of patent claim 1, as well as a turbine having the features of claim 9, and an exhaust gas turbocharger having the features of claim 10. Advantageous embodiments with expedient and non-trivial further developments of the invention are specified in the dependent claims.

[0007] Such an adjustable guide vane for a turbine comprises a bearing ring with a plurality of guide vanes, wherein the guide vanes are rotatably mounted on the bearing ring by means of guide vane shafts. For positioning the guide vane, an adjusting lever is assigned to the guide vane shaft, which is designed to engage with a rotatable rotating ring of the adjustable guide vane. The adjustable guide vane has a support ring for holding it in an exhaust gas guide section of the turbine, which support ring serves to support the rotating ring. The rotating ring is guided radially and / or axially by means of at least one guide element, wherein the guide element is received on the support ring. According to the invention, the guide element is pin-shaped. The advantage lies in a simple structural design of the bearing ring, which is no longer required for the direct support of the rotating ring.The rotating ring is mounted on the support ring, which can be manufactured easily, usually using a forming process, and is usually made of a metal ring with a low material thickness.

[0008] The simple design of the bearing ring allows for reduced material consumption and reduced manufacturing time, as it is less complex. This results in a cost-effective adjustable guide vane.

[0009] Secure guidance of the rotating ring is achieved by forming a contact between the support ring and the rotating ring. Furthermore, the contact on the support ring provides at least one-sided axial support, such that the guide element for secure axial guidance only needs to be designed for one-sided axial support, specifically the existing opposing axial support.

[0010] In a further embodiment of the adjustable guide device according to the invention, at least one support element for receiving the guide element is arranged on the support ring. This allows the support ring to be manufactured with minimal material requirements and, consequently, a low weight.

[0011] In a further embodiment of the adjustable guide vane according to the invention, the support element has a spacer element arranged on the support ring. The spacer element makes it possible to easily achieve an axial spacing of the support element from the support ring. To reduce friction, the support element should have as little contact with the rotating ring as possible. This can be achieved by arranging the support element and the support ring in two different axial planes, with the spacing being achieved by means of the spacer element formed between the support ring and the support element.

[0012] In a further embodiment, the guide element is connected to the support ring in a materially bonded and / or force-locking and / or form-locking manner for secure reception.

[0013] In order to achieve a more cost-effectively manufactured guide device, a press fit is formed between the guide element and the support ring.

[0014] In a further embodiment, the guide element is designed with at least one step. The guide element, which is preferably rotationally symmetrical in the form of a pin or bolt to ensure the smallest possible contact surface between the guide element and the rotating ring, has at least one step on its outer circumference, which can serve to axially support the rotating ring. The axial support is designed on one side, since the step can be provided for a one-sided stop of the rotating ring on the guide element in the axial direction.

[0015] In a further embodiment, the support ring is manufactured cost-effectively using a forming process.

[0016] A further aspect of the invention relates to a turbine for an exhaust gas turbocharger, comprising a flow-through exhaust gas guide section and a turbine wheel rotatably mounted in a wheel chamber of the exhaust gas guide section. An adjustable guide device is arranged upstream of the turbine wheel in the exhaust gas guide section. The adjustable guide device is designed according to one of claims 1 to 8. The advantage of this turbine is an increase in efficiency due to reduced friction of the adjustable guide device.

[0017] In particular, an exhaust gas turbocharger according to the invention with a turbine according to the invention is characterized by a particularly high level of efficiency due to the reduction in friction losses. This, in turn, leads to a reduction in exhaust emissions, particularly in conjunction with an internal combustion engine provided in vehicles, since an increase in the efficiency of the exhaust gas turbocharger leads to optimized coordination between the exhaust gas turbocharger and the internal combustion engine.

[0018] Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. The features and feature combinations mentioned above in the description, as well as those mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention. Identical or functionally equivalent elements are assigned identical reference numerals. For reasons of clarity, it is possible that the elements are not provided with their reference numerals in all figures, although this does not affect their assignment. The figures show: Fig. 1 In a perspective top view of an adjustable guide device according to the invention, Fig. 2 in a perspective section the control apparatus according to. Fig. 1, Fig. 3 in a perspective view a support ring of the guide apparatus according to. Fig. 1, and Fig. 4 in a perspective top view of a bearing ring of the adjustable guide device according to. Fig. 1.

[0019] A flow-through exhaust gas guide section of an exhaust gas turbocharger (not shown in detail) is provided in a flow tract of an internal combustion engine (not shown in detail), which is a gasoline engine or a diesel engine. The exhaust gas turbocharger further comprises a flow-through fresh air guide section (not shown in detail) and a bearing section (not shown in detail), which is arranged in an intake tract of the internal combustion engine (not shown in detail).

[0020] The exhaust gas turbocharger has a rotor assembly (not shown in detail), which includes a compressor wheel (not shown in detail) for intake and compression of combustion air, a turbine wheel (not shown in detail) for exhaust gas expansion, and a shaft (not shown in detail) with a rotational axis that connects the compressor wheel to the turbine wheel in a rotationally fixed manner. The shaft is rotatably mounted in the bearing section of the exhaust gas turbocharger, which is positioned between the air guide section and the exhaust guide section.

[0021] An inlet channel (not shown in detail) is formed in the exhaust duct section to direct the exhaust gas into the exhaust duct section. The inlet channel serves to condition the exhaust gas, which, during engine operation, sets the turbine wheel in rotation. The shaft also rotates the compressor wheel, drawing in and compressing combustion air. Downstream of the inlet channel, a spiral channel (not shown in detail) is arranged in the exhaust gas guide section, which serves to provide a rotationally symmetrical flow. Furthermore, the spiral channel is designed as a connecting channel between the inlet channel and a nozzle channel (not shown in detail), which is positioned downstream of the spiral channel. Downstream of the nozzle channel, a wheel chamber (not shown in detail) is provided in the exhaust gas guide section, in which the turbine wheel is rotatably accommodated. Downstream of the wheel chamber, the exhaust gas guide section has an outlet channel (not shown in detail) for the exhaust gas to escape from the exhaust gas guide section.

[0022] In order to achieve the greatest possible exhaust gas turbocharger efficiency both at low loads and low engine speeds and at high loads and high engine speeds, the exhaust gas can be conditioned by means of an adjustable guide device 1 which is arranged in the exhaust gas guide section.

[0023] An adjustable guide device 1 according to the invention is according to Fig. 1 trained. In Fig. 2, the adjustable guide vane 1 according to the invention is illustrated in a perspective cross-section. The guide vane 1 is designed to surround the turbine wheel in a ring shape and has a bearing ring 2, see in particular Fig. 4, for accommodating guide vanes 3, which are intended for flow conditioning. The guide vanes 3 are rotatably mounted on the bearing ring 2.

[0024] The bearing ring 2 is positioned in the exhaust duct section so that the guide vanes 3 are arranged in the nozzle channel. Positioned opposite the bearing ring 2 is a contour ring 4, which is designed in the form of a cassette to simplify the assembly of the guide vane 1 in the exhaust duct section. Furthermore, the contour ring 4 serves to further support the guide vanes 3.

[0025] For the rotatable mounting of the guide vanes 3 on the bearing ring 2, a guide vane shaft 5 is provided for each guide vane 3, which is connected in a rotationally fixed manner to the guide vane 3 and which is rotatably mounted on the bearing ring 2 and received in a bearing opening 18. For rotating the guide vane shaft 5 and thus the guide vane 3, the guide vane shaft 5 has an adjusting lever 6 at its end facing away from the guide vane 3, which is also connected in a rotationally fixed manner to the guide vane shaft 5.

[0026] The rotational movement of the guide vanes 3 can be initiated by means of a rotating ring 7, which is positioned coaxially with the bearing ring 2 in the adjustable guide vane 1. The rotating ring 7 has recesses 8 into which the adjusting levers 6 are designed to engage, wherein an end of the adjusting lever 6 facing away from the guide vane shaft 5 is ideally provided for engagement in the corresponding recess.

[0027] For axial and radial securing of the rotating ring 7, the adjustable guide device 1 has a support ring 9, which is provided for supporting the adjustable guide device 1 in the exhaust gas guide section. In other words, within the scope of the invention, the support ring 9 is designed to support the rotating ring 7, so that in addition to its original function of supporting the adjustable guide device 1 in the exhaust gas guide section, it also serves to support the rotating ring 7.

[0028] The support ring 9, which is used particularly in Fig. 3 is shown in a perspective view, is immovably fixed to the bearing ring 2 by means of four fastening means 10. The fastening means 10 are designed as screws extending through the support ring 9, wherein these are received in fastening openings 11 of the support ring 9. To accommodate the fastening means 10, the bearing ring 2 has receiving openings 12. Likewise, the fastening means 10 could also be designed, for example, in the form of rivets, whereby any conceivable connection for bringing about a rigid connection between the bearing ring 2 and the support ring 9 is possible.

[0029] The support ring 9 has support elements 13, which are provided for attaching guide elements 14 for guiding the rotating ring 7. In the present exemplary embodiment, the guide elements 14 are designed in the form of guide pins that are immovably connected to the support ring 9. The support elements 13 are designed in the form of support arms, which are designed as ring sections. Likewise, the support element 13 could also be designed in the form of a complete ring, although this would increase the friction between the rotating ring 7 and the support ring 9, since the rotating ring 7 is axially supported on one side by the support ring 9.

[0030] To reduce friction between the rotating ring 7 and the support ring 9, contact between the rotating ring 7 and the support ring 9 occurs exclusively in a relatively small radial area B, which is preferably linear. To minimize the contact, and thus the area B, the support element 13 has a spacer element 17, which causes an axial deposition of the support element 13 relative to the support ring 9, which is received on the support ring 9.

[0031] In the present embodiment, the support element 13 is formed integrally with the support ring 9 and can be manufactured cost-effectively using a forming process, such as a tensile forming process. It could also be connected to the support ring 9 using a material-to-material bonding process.

[0032] The rotating ring 7 is mounted radially and axially on one side, on the side opposite the support element 13, by means of the guide elements 14, wherein the guide elements 14 are immovably received in the support ring 9. In the illustrated embodiment, the guide pins 14 are designed in the form of a bolt-like element with a stepped cross-section. With the help of the steps 15, axial guidance of the support ring 9 can be achieved in a simple and cost-effective manner. The guide elements 14 are received in positioning openings 16 in the support ring 9.

[0033] In a further embodiment not shown in detail, the radial and axial support of the rotating ring 7 is additionally achieved with the aid of guide rollers immovably mounted on the support ring 9. In other words, guide rollers not shown in detail are also provided for the radial and axial securing of the rotating ring 7. The radial support and axial support can also each be assigned to a guide element, i.e., a pin-shaped guide element 14, as shown in the present embodiment, or in the form of the guide roller. Only one support, axial or radial, could also be provided per guide element.

[0034] The guide roller comprises a pin (not shown in detail) and a sleeve (not shown in detail) mounted on the pin for rotation about a pin axis. The sleeve may, for example, have a shoulder, which, in addition to the radial support, enables at least one-sided axial support of the rotating ring 7.

[0035] The guide elements 14, as well as the guide rollers, can be connected to the support ring 9 using a joining method, e.g., riveting, clamping, screwing, or a material-to-material joining method. They are preferably rotationally symmetrical. List of reference symbols 1 Adjustable guide device 2 bearing ring 3 guide vanes 4 contour ring 5 Guide vane shaft 6 adjustment levers 7 Rotating ring 8 Recess 9 Support ring 10 fasteners 11 Mounting hole 12 Receiving opening 13 Support element 14 Guide element 15th level 16 Positioning opening 17 Spacer element 18 Warehouse opening

Claims

[1] Adjustable guide apparatus for a turbine, comprising a bearing ring (2) with a plurality of guide vanes (3), wherein the guide vanes (3) are rotatably mounted on the bearing ring (2) by means of guide vane shafts (5), wherein an adjusting lever (6) is assigned to the guide vane shaft (5) for positioning the guide vane (3), which adjusting lever is designed to engage in a rotatable rotary ring (7) of the adjustable guide apparatus (1), and wherein the adjustable guide apparatus (1) has a support ring (9) for holding it in an exhaust gas guide section of the turbine, and wherein the support ring (9) serves to support the rotary ring (7), wherein the rotary ring (7) is guided radially and / or axially by means of at least one guide element (14), wherein the guide element (14) is received on the support ring (9), characterized by that the guide element (14) is pin-shaped. [2] Adjustable guide device according to claim 1, characterized bythat a contact is formed between the support ring (9) and the rotating ring (7). [3] Adjustable guide device according to claim 1 or 2, characterized by that at least one support element (13) for receiving the guide element (14) is arranged on the support ring (9). [4] Adjustable guide device according to claim 3, characterized by that the support element (13) has a spacer element (17) which is arranged on the support ring (9). [5] Adjustable guide device according to one of the preceding claims, characterized by that the guide element (14) is connected to the support ring (9) in a materially bonded and / or force-locking and / or form-locking manner. [6] Adjustable guide device according to claim 5, characterized by that a press fit is formed between the guide element (14) and the support ring (9). [7] Adjustable guide device according to one of the preceding claims, characterized bythat the guide element (14) is designed to have at least one step (15). [8] Adjustable guide device according to one of the preceding claims, characterized by that the support ring (9) is manufactured by means of a forming process. [9] Turbine for an exhaust gas turbocharger, with a flow-through exhaust gas guide section and a turbine wheel rotatably received in a wheel chamber of the exhaust gas guide section, and wherein an adjustable guide device (1) is arranged upstream of the turbine wheel in the exhaust gas guide section, characterized by that the adjustable guide device (1) is designed according to one of claims 1 to 8. [10] Exhaust gas turbocharger with a turbine designed according to claim 9.

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