A turbocharger with an abradable coating

Abstract

The present invention belongs to the technical field of turbocharging, and provides a turbocharger with an abradable coating, including an impeller, a turbine, a main shaft, a bearing body, a volute, a back plate, and a compression shell; the impeller and the turbine are respectively mounted at the two ends of the main shaft, and the bearing body is mounted in the middle of the main shaft; the volute is mounted at one end of the bearing body and accommodates the turbine in its inner cavity, and the back plate is mounted at the other end of the bearing body; the compression shell is mounted on the back plate and accommodates the impeller in its inner cavity; a groove is provided on the inner cavity wall of the compression shell, and the groove is located in the matching clearance area between the compression shell and the impeller, and the groove is filled with an abradable coating A, and the ratio of its filling thickness to the matching clearance is 60% to 90%. The above technical solution improves the reliability of the abradable coating of the compressor blade tip clearance.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive turbochargers, in particular to small-displacement turbochargers. Background Art

[0002] In recent years, with the upgrading of emission standards, engine miniaturization has become a development trend. In order to improve the specific power of the engine, the most effective method is to match the exhaust gas turbocharger. The comprehensive performance of the exhaust gas turbocharger directly affects the overall performance of the engine, especially the automotive engine pays more attention to low-speed high torque and good fuel economy performance, which puts forward more stringent requirements for the performance improvement of the turbocharger. The improvement of compressor efficiency can effectively improve the performance of the entire turbocharger. Therefore, it is very important to improve the performance of the compressor.

[0003] At present, in addition to improving the compressor stage performance by optimizing the fluid dynamics design of the compressor impeller and volute, the compressor performance can also be improved by controlling the compressor tip clearance. This is because after the miniaturization of the supercharger, the ratio of the tip clearance to the impeller blade height increases, and the influence of the tip clearance on the compressor performance has been upgraded to become an important factor. Chinese Patent Specification No. ZL201720904126.0 discloses a turbocharger that uses an abradable coating for blade tip clearance control. The patented technology seals the blade tip clearance by spraying a coating with an abradable function in the blade tip clearance area of ​​the supercharger. Since the size of the blade tip clearance is effectively controlled, the performance of the compressor is significantly improved. However, during operation, when the impeller scrapes against the abradable coating, the high-speed rotating impeller will generate a large pulling force on the coating in contact with it. In addition, when the speed of the supercharger increases, the increase in the gas pressure ratio causes the temperature of the compressor shell to rise. Under the simultaneous action of temperature and tension, the abradable coating is easily detached from the surface of the compressor shell at the edge, and gradually develops downstream under the blowing of the high airflow velocity of the intake air, destroying the coating. Therefore, the reliability of the coating needs to be further improved. Summary of the invention

[0004] The object of the present invention is to overcome the above-mentioned deficiencies of the prior art and provide a turbocharger with an abradable coating, thereby improving the reliability of the abradable coating of the compressor blade tip clearance.

[0005] In order to solve the above technical problems, the technical solution of the present invention is: a turbocharger with an abradable coating, comprising an impeller, a turbine, a main shaft, a bearing body, a volute, a back plate, and a compression shell; the impeller and the turbine are respectively installed at the two ends of the main shaft, and the bearing body is installed in the middle of the main shaft; the volute is installed at one end of the bearing body and accommodates the turbine in its inner cavity, and the back plate is installed at the other end of the bearing body; the compression shell is installed on the back plate and accommodates the impeller in its inner cavity; a groove is provided on the inner cavity wall of the compression shell, the groove is located in the fitting gap area between the compression shell and the impeller, and the groove is filled with an abradable coating A, and the ratio of its filling thickness to the fitting gap is 60%~90%.

[0006] Preferably, the thickness of the abradable coating A is greater than the depth of the groove, so that the outer surface of the abradable coating A protrudes from the inner cavity wall of the compression shell.

[0007] Preferably, the groove is obtained by machining or casting.

[0008] Preferably, the groove depth is 0.1 mm to 1 mm.

[0009] Preferably, the angle α between the inlet end of the groove and the horizontal direction satisfies 10°≤α≤90°, and the angle β between the outlet end and the vertical direction satisfies 10°≤β≤90°.

[0010] Compared with the prior art, the present invention has the following characteristics:

[0011] 1. A groove of a certain depth is provided at the corresponding position where the abradable coating of the original compressor shell is sprayed, and then the abradable coating is sprayed into the groove, which increases the adhesion area between the coating and the compressor shell surface, and the smoothness of the bottom surface of the groove can be much lower than the smoothness of the original surface of the compressor shell, so that the adhesion ability of the coating is improved.

[0012] 2. The contact area between the coating and the compressor shell is not directly exposed to the air, and will not curl or fall off due to the high-speed airflow of the compressor intake, which significantly improves the reliability of the abradable coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram of the structure of a turbocharger in an embodiment of the present invention;

[0014] Figure 2 for Figure 1 Schematic diagram of the compression shell structure;

[0015] The accompanying drawings are marked as follows:

[0016] 1——Impeller 2——Turbine 3——Main shaft

[0017] 4——Bearing body 5——Voltage casing 6——Back plate

[0018] 7——Compression shell 7-1——Groove A——Abradable coating. DETAILED DESCRIPTION

[0019] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with embodiments and drawings. The contents mentioned in the implementation modes are not intended to limit the present invention.

[0020] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In the description of the present invention, it should be noted that, unless otherwise specified and defined, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection of two elements, it can be a direct connection, or it can be indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meaning of the terms can be understood according to the specific circumstances.

[0021] like Figure 1 , 2 As shown, a preferred embodiment of the present invention is: a turbocharger with an abradable coating, comprising an impeller 1, a turbine 2, a main shaft 3, a bearing body 4, a volute 5, a back plate 6, and a compression shell 7; the impeller 1 and the turbine 2 are respectively mounted at both ends of the main shaft 3, and the bearing body 4 is mounted in the middle of the main shaft 3; the volute 5 is mounted at one end of the bearing body 4 and accommodates the turbine 2 in its inner cavity, and the back plate 6 is mounted at the other end of the bearing body 4; the compression shell 7 is mounted on the back plate 6 and accommodates the impeller 1 in its inner cavity; a groove 7-1 is provided on the inner cavity wall of the compression shell 7, and the groove 7-1 is located in the fitting clearance area between the compression shell 7 and the impeller 1, and an abradable coating A is sprayed in the groove 7-1, and the ratio of its filling thickness to the fitting clearance is 60%~90%.

[0022] like Figure 1 As shown, the thickness of the abradable coating A is greater than the depth of the groove 7-1, so that the outer surface of the abradable coating A protrudes from the inner cavity wall of the compression shell 7; the groove 7-1 in this embodiment is obtained by machining or casting, and its depth is 0.1mm~1mm.

[0023] like Figure 2 As shown, the groove 7-1 is in an arc shape as a whole, and the angle α between its inlet end and the horizontal direction satisfies 10°≤α≤90°, and the angle β between its outlet end and the vertical direction satisfies 10°≤β≤90°.

[0024] Compared with the prior art, the turbocharger provided in this embodiment has the following characteristics:

[0025] 1. A groove 7-1 of a certain depth is provided at the corresponding position of the original compression shell where the abradable coating is sprayed, and then the abradable coating A is sprayed into the groove 7-1, thereby increasing the adhesion area between the coating and the surface of the compression shell, and the smoothness of the bottom surface of the groove 7-1 can be much lower than the smoothness of the original surface of the compression shell, thereby improving the adhesion ability of the coating.

[0026] 2. The contact area between the coating and the compressor shell is not directly exposed to the air, and will not curl or fall off due to the high-speed airflow of the compressor intake, which significantly improves the reliability of the abradable coating.

[0027] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present technical solution is within the protection scope of the present invention.

[0028] In order to make it easier for ordinary technicians in the field to understand the improvements of the present invention over the prior art, some drawings and descriptions of the present invention have been simplified, and for the sake of clarity, some other elements are omitted in this application document. Ordinary technicians in the field should realize that these omitted elements may also constitute the content of the present invention.

Claims

1. A turbocharger with an abradable coating, comprising an impeller (1), a turbine (2), a main shaft (3), a bearing body (4), a volute (5), a back plate (6), and a compression shell (7); the impeller (1) and the turbine (2) are respectively mounted on two ends of the main shaft (3), and the bearing body (4) is mounted in the middle of the main shaft (3); the volute (5) is mounted on one end of the bearing body (4) and accommodates the turbine (2) in its inner cavity, and the back plate (6) is mounted on the other end of the bearing body (4); the compression shell (7) is mounted on the back plate (6) and accommodates the impeller (1) in its inner cavity; characterized in that: A groove (7-1) is provided on the inner cavity wall of the compression shell (7), the groove (7-1) is located in the matching gap area between the compression shell (7) and the impeller (1), the groove (7-1) is filled with an abradable coating A, the ratio of the filling thickness to the matching gap is 60% to 90%, the thickness of the abradable coating A is greater than the depth of the groove (7-1), so that the outer surface of the abradable coating A protrudes from the inner cavity wall of the compression shell (7); the angle α between the inlet end of the groove (7-1) and the horizontal direction satisfies 10°≤α<90°, and the angle β between the outlet end and the vertical direction satisfies 10°≤β<90°; the groove (7-1) is obtained by machining or casting.

2. The turbocharger with an abradable coating according to claim 1, characterized in that: The depth of the groove (7-1) is 0.1mm~1mm.

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