A sealing structure for the nozzle ring of a radial flow turbocharger

Abstract

The present invention discloses a sealing structure for a nozzle ring of a radial flow turbocharger, which includes a nozzle ring, a heat shield, and a support body that are sequentially installed on a turbine housing and are pressed and fixed by a pressing plate; one end of the nozzle ring close to the pressing plate is tightly sealed through a mating surface, and the other end is provided with a labyrinth seal groove structure and a sealing spring piece, and a sealing boss corresponding to the sealing spring piece is provided on the turbine housing. When the nozzle ring is installed in the turbine housing, an interference fit is formed between the sealing spring piece and the sealing boss to form a second sealing structure. The sealing structure for the nozzle ring of the radial flow turbocharger disclosed by the present invention seals by pressing the end face of the turbine housing and the thin sheet, which not only ensures good sealing performance, makes the whole structure simpler and more compact, but also achieves the purpose of eliminating gaps.

Description

Technical Field

[0001] The present invention relates to the technical field of supercharger nozzle seals, and in particular to a seal structure for a nozzle ring of a radial turbine supercharger. Background Art

[0002] Turbochargers are widely used in locomotive diesel engines to improve the power density and economy of locomotive diesel engines. Locomotive radial turbine superchargers adopt a turbine structure with a nozzle ring to increase the expansion ratio and efficiency. The sealing performance at the nozzle ring of the supercharger is one of the main indicators affecting the overall performance. The existing sealing structures at the nozzle ring of the turbocharger mainly adopt labyrinth seals, with graphite gaskets added axially and laminated seal rings added radially. This form of sealing structure is complex in structure and large in overall size. At the same time, the sealing gasket is severely worn under frequent disassembly and is prone to failure. Summary of the Invention

[0003] The present invention proposes a seal structure for a nozzle ring of a radial turbine supercharger in view of the above problems.

[0004] The technical means adopted by the present invention are as follows:

[0005] A seal structure for a nozzle ring of a radial turbine supercharger, comprising a support body, a pressing plate, a heat shield, a nozzle ring, and a turbine housing;

[0006] The nozzle ring, the heat shield, and the support body are sequentially installed on the turbine housing and are pressed and fixed by the pressing plate;

[0007] One end of the turbine housing close to the pressing plate is provided with a turbine housing mating surface, and one end of the nozzle ring close to the pressing plate is provided with a nozzle ring mating surface. When the nozzle ring is installed in the turbine chamber of the turbine housing, the turbine housing mating surface abuts against the nozzle ring mating surface to form a first sealing structure;

[0008] One end of the turbine chamber far from the pressing plate is provided with a nozzle ring receiving groove. When the nozzle ring is installed in the turbine chamber, one end of the nozzle ring far from the pressing plate is placed in the nozzle ring receiving groove;

[0009] A labyrinth seal groove structure is provided on the outer side wall of one end of the nozzle ring placed in the nozzle ring receiving groove, and a sealing spring piece is provided on its inner side wall. A sealing boss corresponding to the sealing spring piece is provided on the inner side wall of the nozzle ring receiving groove. When the nozzle ring is installed in the turbine chamber, an interference fit is formed between the sealing spring piece and the sealing boss along the axial direction of the nozzle ring, so that the side surface of the sealing spring piece abuts against the end surface of the sealing boss to form a second sealing structure.

[0010] Further, when the radial flow turbocharger is in a non-operating state, the interference amount between the sealing spring piece and the sealing boss is 0 mm to 0.05 mm;

[0011] When the radial flow turbocharger is in an operating state, the increase in the interference amount between the sealing spring piece and the sealing boss is not greater than 0.01 mm.

[0012] Further, the thickness of the sealing spring piece is 0.5 to 0.6 mm, and the length is 1.8 to 2.2 mm.

[0013] Further, the surface roughness of the contact surface between the sealing spring piece and the sealing boss is not greater than Ra0.8.

[0014] Further, the material of the nozzle ring is the superalloy K418.

[0015] Further, the labyrinth seal groove structure includes two annular seal grooves, and the width and depth of the annular seal groove closer to the opening end of the nozzle ring accommodation groove are both greater than those of the other annular seal groove.

[0016] Further, a plurality of positioning pins for circumferentially positioning the nozzle ring are also provided in the nozzle ring accommodation groove.

[0017] Compared with the prior art, the radial flow turbocharger nozzle ring sealing structure disclosed by the present invention has the following beneficial effects: Since a labyrinth seal groove structure is provided on the outer side wall of one end of the nozzle ring placed in the nozzle ring accommodation groove, a sealing spring piece is provided on its inner side wall, and a sealing boss is provided on the inner side wall of the nozzle ring accommodation groove, and an interference fit is formed between the sealing spring piece and the sealing boss in the axial direction of the nozzle ring, so that the side surface of the sealing spring piece and the end surface of the sealing boss are in contact to form a second sealing structure, that is, in the present application, a thin plate structure is provided on the nozzle ring, and sealing is performed by pressing the end surface of the turbine housing against the thin plate, which not only ensures good sealing performance, makes the whole structure simpler and more compact, but also achieves the purpose of eliminating gaps. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a partial schematic view of the radial flow turbocharger nozzle ring sealing structure disclosed by the present invention;

[0019] Figure 2 is Figure 1 a partial enlarged schematic view of the dashed box in

[0020] Figure 3 is a partial enlarged view of the labyrinth seal groove structure;

[0021] Figure 4 is a schematic view of the relationship between the sealing spring piece and the sealing boss in the cold state;

[0022] Figure 5 Schematic diagram of the relationship between the sealing spring piece and the sealing boss in the hot state;

[0023] Figure 6 Schematic diagram of gas flow when the nozzle ring sealing structure of the radial flow turbocharger disclosed in the present invention is working.

[0024] In the figure: 1. Support body, 2. Pressure plate, 3. Heat shield, 4. Nozzle ring, 40. Nozzle ring mating surface, 41. Labyrinth seal groove structure, 42. Sealing spring piece, 43. Annular seal groove, 5. Turbine housing, 50. Turbine housing mating surface, 51. Turbine chamber, 52. Nozzle ring receiving groove, 53. Sealing boss, 54. Positioning pin. Detailed implementation manners

[0025] As Figure 1 and Figure 2 shown, the nozzle ring sealing structure of the radial flow turbocharger disclosed in the present invention includes a support body 1, a pressure plate 2, a heat shield 3, a nozzle ring 4 and a turbine housing 5;

[0026] The nozzle ring 4, the heat shield 3 and the support body 1 are sequentially installed on the turbine housing 5 and are pressed and fixed by the pressure plate 2;

[0027] Specifically, the main function of the turbine housing 5 is to collect exhaust gas and conduct it. There is a turbine chamber 51 inside the turbine housing 5. The nozzle ring 4 is arranged in the turbine chamber 51. The main function of the nozzle ring 4 is to increase the exhaust gas flow rate to increase the rotational speed of the turbine placed in the turbine chamber 51. The heat shield 3 is arranged between the nozzle ring 4 and the support body 1. The main function of the heat shield 3 is to isolate the high-temperature exhaust gas entering from the turbine housing 5 from the support body 1 to prevent the temperature inside the support body 1 from being too high. The main function of the support body 1 is to connect the compressor housing and the turbine housing of the turbocharger and be responsible for connecting the inlet and return oil interfaces of the diesel engine. The end face of the support body 1 installed on the turbine housing 5 is slightly higher than the flange face of the turbine housing by 0.1 mm to 0.4 mm. The pressure plate 2 is fixed on the flange of the turbine housing 5 by bolts. The main function of the pressure plate 2 is to press the support body 1 and the turbine housing 5 tightly;

[0028] One end of the turbine housing 5 close to the pressure plate 2 is provided with a turbine housing mating surface 50. One end of the nozzle ring 4 close to the pressure plate 2 is provided with a nozzle ring mating surface 40. When the nozzle ring 4 is installed in the turbine chamber 51 of the turbine housing 5, the turbine housing mating surface 50 abuts against the nozzle ring mating surface 40 to form a first sealing structure;

[0029] One end of the turbine chamber 51 far from the pressure plate 2 is provided with a nozzle ring receiving groove 52. When the nozzle ring 4 is installed in the turbine chamber 51, one end of the nozzle ring 4 far from the pressure plate 2 is placed in the nozzle ring receiving groove 52;

[0030] On the outer wall at one end of the nozzle ring receiving groove 52 where the nozzle ring 4 is placed, there is a labyrinth seal groove structure 41, and on its inner wall, there is a sealing spring piece 42. Preferably, the sealing spring piece 42 and the nozzle ring 4 are of an integral structure, that is, a circular thin sheet structure protruding radially inward is machined on the inner wall of the nozzle ring. On the inner wall of the nozzle ring receiving groove 52, there is a sealing boss 53 corresponding to the sealing spring piece 42. When the nozzle ring 4 is installed in the turbine chamber 51, an interference fit exists between the sealing spring piece 42 and the sealing boss 53 along the axial direction of the nozzle ring 4, so that the side surface of the sealing spring piece 42 and the end surface of the sealing boss 53 are in contact to form a second sealing structure.

[0031] Since the nozzle ring sealing structure disclosed in this application directly uses the sealing spring piece provided on the nozzle ring and the sealing boss provided in the nozzle ring receiving groove to achieve sealing, that is, the deformation of the thin sheet structure is used to seal the high-temperature gas, not only the number of parts is reduced, and other auxiliary sealing parts can be avoided, but also the sealing effect can be achieved directly through the structural cooperation of the parts; at the same time, only one thin sheet fitting space is required axially, greatly saving the axial dimension, and the overall structure is simpler and more compact; the thin sheet is deformable, which can ensure that the fitting can be closely attached, ensuring the reliability of the sealing, and the sealing performance is better at high temperatures.

[0032] Furthermore, as Figure 4 and Figure 5 shown, when the radial flow turbocharger is in a non-operating state (cold assembly), the interference amount between the sealing spring piece 42 and the sealing boss 53 is 0 mm to 0.05 mm; when the radial flow turbocharger is in an operating state (hot state), the increase in the interference amount between the sealing spring piece 42 and the sealing boss 53 is not more than 0.01 mm. The thickness of the sealing spring piece 42 is 0.5 to 0.6 mm, and the length is 1.8 to 2.2 mm; the surface roughness of the contact surface between the sealing spring piece 42 and the sealing boss 53 is not more than Ra0.8; the material of the nozzle ring 4 is the superalloy K418, which has good temperature resistance characteristics and still has a certain elastic limit at high temperatures, and can undergo reversible elastic deformation. In this way, it can ensure that a certain amount of elastic deformation of the thin sheet can be satisfied after cold assembly, but it will not break. In the hot state, according to the fitting dimensions and the linear expansion coefficient of the material, the interference amount will increase, but not exceed 0.01 mm. Therefore, in the working state, good sealing performance can also be maintained here, and at the same time, it is ensured that it will not break, ensuring its sealing performance.

[0033] Furthermore, as Figure 3As shown, the labyrinth seal groove structure 41 includes two annular seal grooves 43. The width and depth of the annular seal groove near the opening end of the nozzle ring accommodation groove 52 are both greater than those of the other annular seal groove. The width and depth of the front-end seal groove are larger, using sufficient labyrinth space to reduce the gas pressure. The width and depth of the rear-end seal groove are smaller, shortening the axial space of the nozzle ring, achieving a compact structure and optimizing the structural layout within a limited space, and further improving the sealing performance at the nozzle ring. Specifically, as Figure 6 shown, when the supercharger disclosed in this application operates, high-temperature gas enters the turbine through the turbine housing and the nozzle ring, providing power for the turbine. On the left side of the gas flow passage, a pressing plate is used to press the mating surface of the nozzle ring and the turbine housing, and the mating surface of the nozzle ring and the turbine housing is pressed tightly to seal the gas. On the right side of the gas flow passage, first, two labyrinth seal grooves with radial mating between the turbine housing and the nozzle ring are used for sealing. After passing through the seal grooves, it enters the clearance fit between the large end face on the right side of the nozzle ring and the end face of the turbine housing. Finally, the thin sheet below the nozzle ring is in interference fit with the step surface of the turbine housing to achieve the sealing of the right side of the gas flow passage.

[0034] Furthermore, as Figure 1 shown, a plurality of positioning pins for circumferentially positioning the nozzle ring are also provided in the nozzle ring accommodation groove. In this embodiment, the nozzle ring is circumferentially positioned by 3 evenly distributed pins to prevent the nozzle ring from rotating. Here, a clearance of 0.1 mm to 0.3 mm is left between the mating surface of the nozzle ring and the turbine housing to ensure that the mating surface 50 of the turbine housing can effectively abut against the mating surface 40 of the nozzle ring to form a first sealing structure.

[0035] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A sealing structure for a nozzle ring of a radial flow turbocharger, characterized in that: It includes a support body, a pressing plate, a heat shield, a nozzle ring and a turbine housing; The nozzle ring, the heat shield and the support body are sequentially installed on the turbine housing and are pressed and fixed by the pressing plate; One end of the turbine housing near the pressing plate is provided with a turbine housing mating surface, and one end of the nozzle ring near the pressing plate is provided with a nozzle ring mating surface. When the nozzle ring is installed in the turbine cavity of the turbine housing, the turbine housing mating surface abuts against the nozzle ring mating surface to form a first sealing structure; One end of the turbine cavity far from the pressing plate is provided with a nozzle ring receiving groove. When the nozzle ring is installed in the turbine cavity, one end of the nozzle ring far from the pressing plate is placed in the nozzle ring receiving groove; A labyrinth seal groove structure is provided on the outer side wall of one end of the nozzle ring placed in the nozzle ring receiving groove, and an annular thin sheet protruding radially inward is machined on its inner side wall. The thickness of the annular thin sheet is 0.5 - 0.6 mm, and the length is 1.8 - 2.2 mm. The annular thin sheet forms a sealing spring piece. A sealing boss corresponding to the sealing spring piece is provided on the inner side wall of the nozzle ring receiving groove. When the nozzle ring is installed in the turbine cavity, the sealing spring piece and the sealing boss are in interference fit along the axial direction of the nozzle ring. When the radial flow turbocharger is in a non-operating state, the interference amount between the sealing spring piece and the sealing boss is 0 mm - 0.05 mm; when the radial flow turbocharger is in an operating state, the increase in the interference amount between the sealing spring piece and the sealing boss is not greater than 0.01 mm, so that the side surface of the sealing spring piece abuts against the end surface of the sealing boss to form a second sealing structure.

2. The nozzle ring sealing structure of the radial flow turbocharger according to claim 1, wherein: The surface roughness of the abutting surface between the sealing spring piece and the sealing boss is not greater than Ra0.

8.

3. The nozzle ring sealing structure of the radial flow turbocharger according to claim 2, characterized in that: The material of the nozzle ring is high-temperature alloy K418.

4. The nozzle ring sealing structure of the radial flow turbocharger according to claim 1, characterized in that: The labyrinth seal groove structure includes two annular seal grooves. The width and depth of the annular seal groove near the opening end of the nozzle ring receiving groove are both greater than those of the other annular seal groove.

5. The sealing structure of the nozzle ring of the radial flow turbocharger according to claim 1, wherein: A plurality of positioning pins for circumferentially positioning the nozzle ring are further provided in the nozzle ring receiving groove.

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