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 designed to be in contact with the support ring (9), characterized in that the rotating ring (7) is guided radially and / or axially by means of at least one guide pin (13) and / or a guide roller (17), wherein the guide pin (13) and / or the guide roller (17) is received on the support ring (9).

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 6 and an exhaust gas turbocharger according to claim 7.

[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 accommodated 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 accommodated. 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 accommodating 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 document DE 10 2008 014 678 A1 an adjustable guide device is known, comprising at least one rolling element which is arranged on an associated fastening element of the adjustable guide device, wherein the rotating ring of the adjustable guide device can roll on the rolling element.

[0005] The documents WO 2016 / 199 600 A1 and DE 11 2016 002 591 T5 disclose an adjustable guide vane for a turbine, in particular a turbine of an exhaust gas turbocharger. The rotating ring is disk-shaped and supported on a drive ring support element so that it can be rotated. The drive ring support element and a support ring, which is designed to hold the guide vane in a turbine housing of the turbine, are riveted together, whereby the rotating ring is designed to be contact-free with the support ring.

[0006] 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.

[0007] 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 6, and an exhaust gas turbocharger having the features of claim 7. Advantageous embodiments with expedient and non-trivial further developments of the invention are specified in the dependent claims.

[0008] 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 rotary 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 mount the rotary ring. According to the invention, the rotary ring is designed to be contact-free with the support ring, wherein the rotary ring is guided radially and / or axially by means of at least one guide pin and / or a guide roller, wherein the guide pin and / or the guide roller is received on the support ring.

[0009] The advantage lies in the simple design of the bearing ring, which is no longer required for the direct support of the rotating ring. The rotating ring is supported on the support ring, which can be easily manufactured, usually using a stamping process, and is usually made of a thin metal ring.

[0010] 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 diffuser. Since there is no contact between the support ring and the rotating ring, friction between the movable elements of the adjustable diffuser is significantly reduced. This allows for faster adjustment of the guide vanes, which in turn improves the turbine wheel's responsiveness.

[0011] The rotating ring is guided radially and / or axially by at least one guide pin and / or a guide roller, with the guide pin and / or the guide roller being mounted on the support ring. The advantage is the creation of a friction-reduced, adjustable guide device. Thus, with the help of the guide pin, in particular with the help of axial contact surfaces formed on the guide pin, a specific friction coefficient and thus the friction occurring can be adjusted, in particular reduced. With the help of the guide roller, a radial contact can be created with reduced friction.

[0012] When the guide roller is used, the axial guidance is partially or completely eliminated, which further reduces friction.

[0013] A combination of guide pin and roller reduces friction while ensuring the guiding function and at the same time offers the potential for cost optimization.

[0014] In a further embodiment, the support ring is designed in the form of a flat disc ring, which allows it to be manufactured cost-effectively. It can, for example, be produced using a pure stamping process. In other words, no further process and / or work step is required apart from the stamping process, so the support ring can be manufactured cost-effectively.

[0015] In a further embodiment of the adjustable guide device according to the invention, the support ring is connected to the guide pin and / or the guide roller in a materially bonded and / or force-locked and / or form-locked manner.

[0016] A further cost-effective production of the adjustable guide device is achieved by a press fit formed between the guide pin and / or the guide roller and the support ring.

[0017] In a further cost-effective embodiment of the guide vane according to the invention, the support ring can be manufactured by stamping. Stamping is an extremely cost-effective and simple manufacturing process, particularly for thin components, allowing for the realization of a cost-effective, adjustable guide vane.

[0018] 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 5. The advantage of this turbine is an increase in efficiency due to reduced friction of the adjustable guide device.

[0019] 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.

[0020] 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, Fig. 4 in a perspective top view of a bearing ring of the adjustable guide device according to. Fig. 1, and Fig. 5 shows a perspective section of the adjustable guide device according to the invention in an alternative embodiment.

[0021] 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).

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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 in the exhaust duct section to simplify the assembly of the guide vane 1. Furthermore, the contour ring 4 serves to further support the guide vanes 3.

[0028] 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 20. 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.

[0029] 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.

[0030] 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 for the indirect support of 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.

[0031] The support ring 9, which is used particularly in Fig. 3 is shown in a perspective view, is designed to be non-contact with the rotating ring 7. It is immovably fixed to the bearing ring 2 by means of four fastening means 10. The fastening means 10 are in the form of screws extending through the support ring 9, which are received in fastening openings 11 of the support ring 9. The bearing ring 2 has receiving openings 12 to accommodate the fastening means 10.

[0032] The rotating ring 7 is mounted radially and axially by means of guide pins 13, which are immovably received in the support ring 9. In the illustrated embodiment, the guide pins 13 are designed as bolt-like elements with a groove 15. The groove 15 allows for simple and cost-effective axial guidance of the support ring 9. The guide pins 13 are received in positioning openings 16 in the support ring 9.

[0033] In another embodiment, see Fig. 5, the radial and axial support of the rotating ring 7 is additionally carried out by means of guide rollers 17 which are immovably mounted on the support ring 9. In other words, guide pins 13 and guide rollers 17 are also provided for the radial and axial securing of the rotating ring 7.

[0034] The radial bearing and axial bearing can each be assigned to a guide element 13, 17, i.e., the guide pin 13 or the guide roller 17. Also, only one bearing, axial or radial, could be provided per guide element 13, 17.

[0035] The guide roller 17 comprises a pin 18 and a sleeve 19 which is mounted on the pin 18 and is rotatable about a pin axis 14. This form of bearing is designed similarly to a rolling bearing, since the rotating ring 7 can roll on the sleeve 19, and leads to a low-friction bearing of the rotating ring 7. The sleeve 19 has a shoulder 21, with the aid of which an at least one-sided axial bearing of the rotating ring 7 is possible in addition to the radial bearing.

[0036] The guide rollers 17 and the guide pins 13 can be connected to the support ring 9 by means of a joining process, e.g. rivets, clamps, screws or a material-to-material joining process.

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 mount the rotary ring (7), wherein the rotary ring (7) is designed to be contact-free with the support ring (9), characterized by that the rotating ring (7) is guided radially and / or axially by means of at least one guide pin (13) and / or a guide roller (17), wherein the guide pin (13) and / or the guide roller (17) is received on the support ring (9). [2] Adjustable guide device according to claim 1, characterized by that the support ring (9) is designed in the form of a flat disc ring. [3] Adjustable guide device according to one of the preceding claims, characterized by that the support ring (9) is connected to the guide pin (13) and / or the guide roller (17) in a materially bonded and / or force-locking and / or form-locking manner. [4] Adjustable guide device according to one of the preceding claims, characterized by that a press fit is formed between the guide pin (13) and / or the guide roller (17) and the support ring (9). [5] Adjustable guide device according to one of the preceding claims, characterized by that the support ring (9) is manufactured by means of a stamping process. [6] 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 5. [7] Exhaust gas turbocharger with a turbine designed according to claim 6.

Images