Turbocharger metal seal ring leakage test device and test method

Abstract

This invention relates to a test device and method for testing the leakage of metal seal rings in turbochargers, belonging to the field of turbocharger performance testing technology. It includes a simplified turbine housing, a simplified bearing housing, bolts, a pressure plate, and a housing. The simplified turbine housing and the simplified bearing housing are mated to form a pressing surface. The dimensions, roughness, seal ring installation position, and heat shield structure of the simplified turbine housing are consistent with the turbocharger under test. The seal ring installation position is consistent with the turbocharger. The bolts are tightened to the turbocharger installation torque. The housing is fitted over the pressure plate and bolts, and its bottom is pressed against the simplified bearing housing. The junction is welded with a circumferential weld to form a sealed cavity with no leakage except at the test point. The simplified turbine housing is provided with sensor holes and measurement holes. This invention simulates the actual installation conditions of the turbocharger, eliminates interference from non-seal ring leakage, achieves accurate measurement of leakage performance, and prevents secondary damage or scratches to the seal ring during disassembly after the test.

Description

Technical Field

[0001] This invention belongs to the field of turbocharger performance testing technology, and particularly relates to a turbocharger metal seal leakage testing device and test method. Background Technology

[0002] The turbocharger is a key component of the internal combustion engine, operating in extreme environments of high temperature, high pressure, and high speed. The metal seal, as a crucial sealing element between the turbocharger turbine housing and the bearing housing, directly affects the turbocharger's efficiency, reliability, and emissions levels. In actual operation, the metal seal must withstand high-temperature combustion gases, pressure pulsations, and thermal cycling shocks. Insufficient sealing performance will lead to high-temperature combustion gas leakage, causing bearing damage, oil deterioration, and even complete engine failure.

[0003] In existing technologies, the performance testing of metal seals typically employs simple flat plate clamping or general-purpose cavity testing devices. These devices suffer from the following technical drawbacks: The test environment is inconsistent with the actual working conditions: Existing test equipment usually uses standard flanges or simple pressure plates to tighten the sealing ring, which cannot simulate the actual pressure surface structure in the turbocharger (such as heat shield structure, end face roughness, sealing groove size, etc.), resulting in a significant deviation between the test results and the actual performance.

[0004] Inaccurate preload control: Existing devices often provide clamping force through simple tightening or hydraulic methods, which cannot guarantee the same bolt torque and preload distribution as when the booster is actually installed. This results in the compression and contact stress state of the sealing ring not matching the actual working conditions.

[0005] Poor accuracy of leakage measurement: The cavity sealing of existing devices is difficult to guarantee. In addition to the sealing ring itself, there are often other leakage channels (such as flange mating surfaces, bolt holes, etc.), which means that the measured "leakage" includes leakage that is not from the sealing ring itself, making it impossible to accurately evaluate the true sealing performance of the metal sealing ring.

[0006] Post-test inspection is difficult: Existing devices are mostly closed welded structures or integrally machined structures. When disassembling after the test, they are prone to secondary damage or scratches on the metal sealing ring, making it impossible to accurately inspect the morphology, conduct microscopic analysis, and assess the damage to the metal sealing ring.

[0007] Therefore, there is an urgent need for a testing device that can realistically simulate the actual installation conditions of a turbocharger, accurately measure the leakage performance of metal seals, and prevent secondary damage or scratches to the seals during disassembly after the test. Summary of the Invention

[0008] To address the problems in the prior art, this invention proposes a test device and method for testing the leakage of metal seal rings in turbochargers. This solves the technical problems in the prior art, such as the inconsistency between the test environment and actual working conditions, inaccurate preload control, interference in leakage measurement, and difficulties in post-test detection.

[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: it includes a simplified turbine housing, a simplified bearing body, bolts, a pressure plate, and a housing. The simplified turbine housing and the simplified bearing housing are mated to form a metal sealing ring clamping surface. The sealing end face structure dimensions, surface roughness, and metal sealing ring installation position of the clamping surface are consistent with those of the turbocharger under test. If the clamping surface of the turbocharger under test is provided with a heat shield structure, then the clamping surface is provided with a heat shield of the same structure and dimensions as the turbocharger under test; if the clamping surface of the turbocharger under test is not provided with a heat shield structure, then the simplified turbine housing and the simplified bearing housing directly constitute the clamping surface. The installation position of the metal sealing ring is consistent with the installation position in the turbocharger under test; The bolts and the pressure plate are assembled according to the installation requirements of the turbocharger under test, and the bolt tightening torque is the same as the installation torque of the turbocharger under test, to ensure that the preload of the metal sealing ring is consistent with the preload in the turbocharger under test; The outer casing has a measuring hole on its side for measuring the leakage rate or leakage amount of the metal sealing ring. The outer casing is fitted on the outside of the pressure plate and the bolt, and its bottom is pressed tightly against the simplified bearing body. The junction of the outer casing and the simplified turbine box forms a welded annular surface, and a seal is achieved by welding, thus forming a sealed cavity with no other leakage channels except for the measuring point. The simplified turbine housing has sensor holes on its straight section of pipe for measuring inlet temperature and pressure.

[0010] Furthermore, the outer wall of the outer shell has a stepped structure from top to bottom, which facilitates cutting and disassembly after testing.

[0011] Furthermore, the welding annular surface is an annular mating surface formed between the upper end face of the outer shell and the outer peripheral surface of the simplified turbine housing, which forms a full-circumference sealed weld after welding.

[0012] Furthermore, a positioning stop structure is provided at the mating end face of the simplified turbine housing and the simplified bearing body. The positioning stop structure achieves radial positioning during assembly of the two through cylindrical surface mating, which is used to ensure the coaxiality and end face parallelism of the two.

[0013] Furthermore, a metal sealing ring mounting reference structure is provided on the pressing surface. The mounting reference structure is located radially inside the positioning stop structure, and its structural dimensions are consistent with those of the turbocharger to be tested.

[0014] Furthermore, the sensor holes are located at the inlet end of the simplified turbine housing straight section pipeline, and are evenly distributed in multiple locations along the circumference of the pipeline.

[0015] Furthermore, the measuring hole is located on the side of the outer casing near the metal sealing ring and is in communication with the sealed cavity.

[0016] Furthermore, the welding ring surface is welded around its entire circumference using argon arc welding or laser welding.

[0017] Furthermore, the test method for the turbocharger metal seal leakage test device includes the following steps: S1: Based on the clamping surface structure of the turbocharger to be tested, select a simplified turbine housing and simplified bearing body with or without a heat shield to ensure that the structural dimensions, roughness, and sealing ring installation position of the clamping surface are consistent with the turbocharger to be tested. S2: Install the metal sealing ring in the same position as the turbocharger to be tested; S3: Install the pressure plate and bolts, and tighten the bolts according to the installation torque of the turbocharger to be tested, so that the metal seal rings obtain the same preload force as in the turbocharger to be tested; S4: The outer casing is fitted onto the outside of the pressure plate and bolts, so that the bottom of the outer casing is pressed against the simplified bearing body, and the welded annular surface at the junction of the outer casing and the simplified turbine box is welded and sealed to form a sealed cavity with no leakage channels except for the measuring hole and sensor hole; S5: Install the assembled test device on the turbocharger test bench, measure the inlet temperature and pressure through the sensor hole, and measure the leakage rate or leakage amount of the metal seal through the measuring hole; S6: After the test, cut along the stepped outer wall of the shell, remove the shell, then remove the bolts and pressure plate, and take out the metal sealing ring for damage inspection.

[0018] Furthermore, in the test method of the turbocharger metal seal ring leakage test device, in step S4, the welding ring surface is cleaned before welding, and after welding, helium mass spectrometry leak detection or gas pressure leak detection is used to verify that there are no other leakage points except for the measuring hole and sensor hole.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects.

[0020] 1. This invention employs a simplified turbine housing and a simplified bearing body that are identical in structure, surface roughness, seal ring installation position, and heat shield structure to the turbocharger under test. A simplified turbine housing is then joined to form a clamping surface. Bolts and pressure plates are tightened strictly according to the turbocharger's installation torque to ensure consistent preload. A shell is then fitted onto the outside, its bottom clamping to the simplified bearing body, and the junction is sealed by welding a ring surface. This creates a sealed cavity with no leakage channels other than the sensor and measurement holes. This realistically simulates the actual installation conditions and thermal boundary conditions of the metal seal ring in the turbocharger, eliminating interference from non-seal ring leakage channels on the measurement results. This enables accurate measurement of the leakage rate or amount of the metal seal ring. Furthermore, the stepped structure on the outer side of the shell facilitates cutting and disassembly after the test, ensuring the authenticity and completeness of the seal ring damage inspection after the test. This provides a reliable basis for seal ring performance evaluation and failure analysis.

[0021] 2. By making the pressure surface structure dimensions, surface roughness, sealing ring installation position, and heat shield structure (if any) of the simplified turbine housing and simplified bearing housing completely consistent with the turbocharger under test, this invention ensures that the geometric environment and thermal boundary conditions of the metal sealing ring during the test are highly consistent with the actual operating conditions, which greatly improves the accuracy and reference value of the test results.

[0022] 3. This invention uses the same bolt specifications, installation sequence, and tightening torque as the turbocharger to ensure that the preload obtained by the metal sealing ring is consistent with the actual installed state, thus solving the problem of test distortion caused by inaccurate preload control in the prior art.

[0023] 4. This invention constructs a sealed cavity with no leakage channels other than the measuring hole and sensor hole by welding the outer shell to the simplified turbine housing and pressing the bottom of the outer shell against the simplified bearing body. This means that the measured leakage amount originates entirely from the metal sealing ring itself, eliminating interference from other leakage channels and achieving an accurate evaluation of the sealing performance of the metal sealing ring.

[0024] 5. The outer shell of the present invention adopts a stepped outer wall structure from top to bottom, which provides convenient operating space and clear cutting path for cutting and disassembly after the test, avoids damage to the sealing ring and pressing surface by violent disassembly, ensures the authenticity and integrity of the sealing ring damage state after the test, and facilitates failure analysis and life assessment.

[0025] 6. This invention forms a complete testing closed loop, from assembly, welding and sealing, bench testing to disassembly and inspection. It can not only quantitatively evaluate leakage performance, but also establish the correlation between leakage and seal damage state through morphological inspection of the seal ring after the test, providing data support for the optimized design and life prediction of the seal ring. Attached Figure Description

[0026] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the structure of the turbocharger metal seal leakage test device described in this invention.

[0027] Explanation of reference numerals in the attached figures: 1. Simplified turbine housing; 11. Straight section pipeline; 111. Sensor hole; 12. Lower end face flange; 121. Internal stop; 122. Threaded blind hole; 13. Inlet flange; 2. Simplified bearing body; 21. Butt flange; 211. Second sealing groove; 22. Support base; 3. Metal sealing ring; 4. Bolt; 5. Pressure plate; 51. Bolt through hole; 6. Housing; 61. Measuring hole; 62. First step; 63. Second step; 64. Third step; 7. Welded annular surface. Detailed Implementation

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0029] In the description of this invention, it should be understood that the technical terms "lower end," "inner," "bottom," "upper end," "axial," "inner," "outer," and "lower segment," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "first," "second," "third," and similar words used in the embodiments of this invention do not indicate any order, quantity, or importance, but are only used to distinguish different components. "A plurality of" refers to two or more.

[0030] Words such as "include" or "contain" mean that the element preceding the word covers the element listed after the word and its equivalents, without excluding other elements. Words such as "connect" or "fix" are not limited to a single connection or fixing method, but can include multiple connection or fixing methods, such as screw fastening, threaded connection, welding, etc.

[0031] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0032] A test apparatus and method for leak testing of metal seal rings in turbochargers, comprising: a simplified turbine housing 1, a straight section of pipe 11, a sensor hole 111, a lower end flange 12, an inner stop 121, a threaded blind hole 122, an inlet flange 13, a simplified bearing body 2, a mating flange 21, a second sealing groove 211, a support base 22, a metal seal ring 3, bolts 4, a pressure plate 5, bolt through holes 51, a housing 6, a measuring hole 61, a first-stage step 62, a second-stage step 63, a third-stage step 64, and a welded annular surface 7.

[0033] Install the metal sealing ring 3 in the second sealing groove 211 of the simplified bearing body 2, and then assemble the simplified bearing body 2 onto the lower end flange 12 of the simplified turbine box 1. Then press the pressure plate 5 onto the bottom surface of the mating flange 21 of the simplified bearing body 2, and fix it to the simplified turbine box 1 with bolts 4; Finally, the outer casing 6 is welded to the lower end flange 12 of the simplified turbine housing 1.

[0034] Preferably, the outer side wall of the outer casing 6 has a stepped structure from top to bottom, which facilitates cutting and disassembly after the test; After the test, the welded annular surface 7 between the outer shell 6 and the simplified turbine housing 1 formed a permanent sealed weld, and the interior of the outer shell 6 is a sealed cavity, making it impossible to pull out axially directly. The stepped structure forms multiple steps and transition cone surfaces on the outer wall of the outer shell 6, providing a clear radial reference line for abrasive wheel cutting, wire cutting, or turning. Operators can cut segment by segment along the transition areas of each step, avoiding the risks of slippage, off-center cutting, or damage to internal bolts and pressure plates that are easily caused when blindly cutting on a smooth cylindrical surface; After the test apparatus operates under high temperature and high pressure conditions, the outer shell 6 may become tightly bound to the internal parts due to residual welding stress and thermal expansion and contraction. If a circumferential cut is used, the elastic deformation or clamping force generated when the outer shell 6 breaks at one time may squeeze the pressure plate 5 and the simplified bearing body 2 inward, causing the metal sealing ring 3 to be deformed under pressure or to have secondary scratches on its surface, interfering with the determination of the true damage state of the metal sealing ring 3 after the test. The stepped structure allows the outer shell 6 to be cut off in multiple segments from top to bottom. Each segment cut off releases a portion of the residual stress, gradually relieving the radial constraint on the internal components of the outer shell 6, ensuring that the morphology of the metal sealing ring 3 remains in its original state at the end of the test when it is finally removed. The simplified turbine housing 1 and simplified bearing housing 2 are the core reference components of the device. The surface roughness of their clamping surfaces and the fitting accuracy of the inner stop 121 directly affect the test accuracy and require long-term repeated use. The stepped outer shell 6 is a disposable consumable. After being cut and removed in sections, it avoids disassembly by means of violent hammering, heating expansion, or forced pulling. This protects the lower end flange 12 of the simplified turbine housing 1, the mating flange 21 of the simplified bearing housing 2, and the mating surface of the inner stop 121 from damage, significantly reducing the maintenance cost and recalibration frequency of the core components. The upper part of the outer shell 6, near the welding ring 7, typically has a thicker wall to withstand the heat of welding, while the lower part can have a relatively thinner wall to save material. The stepped structure naturally creates sections with different outer diameters, corresponding to different wall thicknesses. Operators can select appropriate cutting tools and feed rates according to the wall thickness of each section, improving disassembly efficiency and reducing scratches from burrs on internal parts. Post-test damage inspection of the metal sealing ring 3 (including visual inspection of cracks, cross-sectional dimension measurement, and scanning electron microscopy analysis) requires that the surface of the metal sealing ring 3 be free of scratches or indentations introduced during disassembly. The segmented cutting method of the stepped outer shell fundamentally eliminates the risk of fragments of the outer shell 6 falling into the sealing area or the sealing ring rolling due to cutting vibration during overall disassembly. This ensures that the metal sealing ring 3 removed after testing accurately reflects its failure state under bench test conditions, giving the correlation analysis between leakage rate data and damage morphology engineering credibility.

[0035] Preferably, the welding annular surface 7 is an annular mating surface formed between the upper end face of the outer shell 6 and the outer peripheral surface of the simplified turbine box 1, and a full-circumference sealed weld is formed after welding; The full-circumference sealing weld solidifies the outer shell 6 and the simplified turbine housing 1 into a non-removable sealed whole, fundamentally eliminating the gas leakage channel at their interface. Combined with the compression fit between the bottom of the outer shell 6 and the simplified bearing body 2, the entire device forms a sealed cavity that communicates with the outside world only through the measuring hole 61 and the sensor hole 111. This ensures that the leakage data collected through the measuring hole 61 during bench testing originates entirely from the sealing failure of the metal sealing ring 3 itself, eliminating the interference of leakage from other mating surfaces of the device on the measurement results, and significantly improving the accuracy and reliability of the leakage rate test. The upper surface of the outer shell 6 and the outer peripheral surface of the simplified turbine box 1 form a typical corner joint or T-joint, providing ample space for welding operations. The welding torch or laser head can approach the welding ring surface from the outside of the device without obstruction at 360°. The welding form of the outer peripheral surface makes it easier to achieve uniform penetration depth throughout the circumference, facilitating the use of automated welding equipment (such as automatic circumferential TIG welding) to ensure consistent weld quality and reduce the probability of welding defects. The full-circumference circumferential weld ensures a uniform distribution of welding stress along the circumference, avoiding localized stress concentration. Under the high-temperature and high-pressure environment of bench testing, the circumferential weld can uniformly withstand the axial thrust generated by the gas pressure inside the cavity. The weld is under compression rather than tension, which helps maintain the integrity of the seal. At the same time, since the outer wall of the outer shell 6 is stepped with the largest outer diameter at the upper end, it naturally transitions with the outer circumferential surface of the simplified turbine housing 1 to form a welding ring surface, eliminating the need for additional welding gaskets or complex beveling, simplifying the structure and reducing stress concentration sources. After testing, the outer casing 6 needs to be cut and removed along its stepped sidewall. Positioning the welded annulus between the uppermost part of the outer casing 6 and the outer circumference of the simplified turbine housing 1 means that the cutting operation only needs to be performed on the lower middle part of the stepped sidewall of the outer casing 6, without touching or damaging the weld at the top or the simplified turbine housing 1 itself. This ensures absolute sealing during testing and prevents damage to the precision mating surfaces of the simplified turbine housing during disassembly after testing, achieving a balance between "high sealing performance" and "disassembly capability."

[0036] Preferably, a positioning stop structure is provided at the mating end face of the simplified turbine housing 1 and the simplified bearing body 2. The positioning stop structure achieves radial positioning during assembly of the two through cylindrical surface mating, which is used to ensure the coaxiality and end face parallelism of the two. Regardless of whether the positioning stop structure adopts an inner stop 121, an outer stop, or a combination of a stop and a positioning pin, the positioning stop structure achieves automatic centering through cylindrical surface mating. During assembly, the mating end face of the simplified bearing body 2 slides into place along the mating surface of the positioning stop structure, and their axes automatically coincide, avoiding eccentric assembly caused by manual alignment errors. This ensures that the metal sealing ring 3 obtains a uniform compression amount throughout the entire circumference, preventing local over- or under-pressure and ensuring that the sealing ring test condition is consistent with the booster's installed condition. The mating surfaces and clamping end faces of the positioning stop structure are typically machined in a single clamping operation, resulting in high relative positional accuracy. During assembly, the mating surfaces not only achieve radial positioning, but their mating depth also ensures that the two clamping end faces remain parallel before clamping. After bolt 4 is tightened, the two clamping end faces fit evenly without warping or gaps, preventing leakage caused by non-sealing ring issues due to non-parallel end faces, and ensuring that leakage measurements accurately reflect the sealing performance of the metal sealing ring. With the help of the positioning stop structure, no additional tooling or precision measuring instruments are needed for alignment during assembly. Precise alignment can be achieved simply by pushing the mating end faces into place along the stop. This significantly reduces assembly time and operational difficulty, while eliminating test variables introduced by human error during assembly, thus improving test repeatability and data reliability. During the test, the high-temperature and high-pressure airflow inside the pipeline will generate lateral forces and vibrations. The cylindrical surface of the positioning stop structure can withstand part of the radial load, preventing the load from being borne entirely by bolt 4, preventing the bolt connection from loosening or the clamping surfaces from slipping, thereby maintaining the preload of the metal sealing ring stable throughout the test. The positioning stop structure directly replicates the assembly positioning benchmark of the actual turbocharger, making the installation state of the sealing ring in the test device completely consistent with the actual installation state at the geometric benchmark level. This fundamentally solves the test distortion problem caused by the lack or difference of the assembly benchmark in the existing technology.

[0037] Preferably, a metal sealing ring mounting reference structure is provided on the pressing surface. The mounting reference structure is located on the radial inner side of the positioning stop structure, and its structural dimensions are consistent with those of the turbocharger to be tested. By setting a metal seal ring mounting reference structure on the clamping surface that is completely identical to the structural dimensions of the turbocharger under test, and arranging this mounting reference structure radially inside the positioning stop structure, the installation position of the metal seal ring 3 (including radial position, axial depth, and circumferential positioning) is highly consistent with the actual installed state of the turbocharger. Therefore, the geometric constraints, compression deformation space, and pressure boundary of the metal seal ring 3 during the test are the same as those under real working conditions, ensuring that the compression amount, contact stress distribution, and sealing specific pressure of the seal ring are consistent with the installed state. This guarantees that the leakage test data can truly reflect the sealing performance of the metal seal ring 3 under actual working conditions. By placing the locating stop structure on the radially outer side of the mounting reference structure, the simplified turbine housing 1 and the simplified bearing body 2 achieve precise alignment of coaxiality and end face parallelism through the outer locating stop during assembly, and then form a stable sealing ring clamping reference on the radially inner side. This layout avoids the problem of eccentric compression or local over-compression of the sealing ring caused by positioning errors, ensures that the metal sealing ring 3 obtains a uniform preload in the circumferential direction, eliminates additional leakage variables introduced by assembly coaxiality deviations, and significantly improves the accuracy and repeatability of leakage rate measurement results. The mounting reference structure is directly integrated onto the clamping surface, eliminating the need for additional independent sealing ring positioning elements. This reduces the accumulation of errors during assembly and avoids the formation of potential micro-leakage channels between additional components and the clamping surface, further ensuring the technical effect that the testing device has no leakage paths other than the measurement points.

[0038] Preferably, the sensor holes 111 are located at the inlet end of the straight section of the simplified turbine housing 1 pipe 11, and are evenly distributed in multiple locations along the circumference of the pipe; The inlet is located in the upstream straight section where the working medium enters the test chamber. At this position, the airflow has not yet been disturbed by the sealing ring pressing surface and the downstream flow channel structure. The original temperature and pressure parameters of the high-temperature and high-pressure working medium entering the device can be directly obtained, avoiding measurement distortion caused by local eddies, cross-sectional changes, or backflow in the sealing ring area. This provides reliable boundary condition data for accurate calculation of the leakage rate. Because high-temperature gas in pipelines may exhibit uneven distribution of circumferential temperature and pressure fields due to gravity, velocity distribution, or eddy current effects, a single measuring point is insufficient to represent the true average state of the cross-section. By using multiple uniformly distributed sensor holes 111 along the circumference, multiple sets of data can be collected simultaneously on the same cross-section. After averaging, more representative inlet temperature and pressure values ​​are obtained, significantly improving measurement accuracy and the repeatability of test results. Existing testing devices often place sensors on the side of the cavity or near the sealing ring. The measurement point location is easily affected by local heat conduction, leaking airflow at the sealing surface, or heat dissipation from the outer casing, resulting in the measured temperature and pressure not accurately reflecting the inlet operating conditions. This structure moves the measurement point forward to the straight section at the inlet end and adopts a circumferentially evenly distributed method, fundamentally eliminating the interference of downstream structures on the measurement results and ensuring that the test boundary conditions are highly consistent with the actual operating conditions of the turbocharger under test.

[0039] Preferably, the measuring hole 61 is located on the side of the outer casing 6 near the metal sealing ring 3 and communicates with the sealed cavity. This allows the measuring hole 61 to be directly adjacent to the leakage source of the metal sealing ring 3. After the leaking gas escapes from the failure point of the metal sealing ring 3, it can enter the measuring hole 61 without diffusing through a long flow channel, shortening the transmission path of the leaking gas and reducing the measurement error caused by gas diffusion, condensation, or pressure decay in the cavity. This improves the sensitivity and real-time performance of leakage rate or leakage amount measurement. Simultaneously, placing the measuring hole 61 on the side of the outer casing 6 instead of on the simplified turbine housing 1 avoids additional drilling and machining of the simplified turbine housing 1's main structure, maintaining the structural integrity and strength of the inner stop and clamping surface of the lower end face of the simplified turbine housing 1, ensuring that it can accurately reproduce the clamping surface state of the turbocharger under test. Furthermore, since the outer casing 6 is a temporary component that needs to be cut and removed after the test, having the measuring hole 61 on its side does not affect the reuse of the simplified turbine housing 1 and the simplified bearing body 2, reducing the manufacturing cost and cycle time of the test device.

[0040] Preferably, the welding annular surface 7 is welded around its entire circumference using argon arc welding or laser welding, forming a continuous and dense annular sealing weld between the simplified turbine housing 1 and the outer casing 6. This type of welding method concentrates heat input and has a narrow heat-affected zone, effectively controlling welding deformation and preventing residual welding stress from causing warping of the outer casing 6 or the flange of the simplified turbine housing 1. This ensures that the welding annular surface 7 maintains a stable sealing pressure under high temperature and high pressure conditions during testing. Full-circumference welding eliminates any possible circumferential leakage gaps, ensuring that the device communicates with the outside world only through the pre-set measurement hole 61 and sensor hole 111. This ensures that the leakage measured during the test originates entirely from the metal sealing ring 3 itself, eliminating interference from non-sealing ring leakage at the welding annular surface 7 and significantly improving the accuracy and reliability of the leakage rate or leakage amount measurement of the metal sealing ring 3. Argon arc welding and laser welding are suitable for thin-walled outer casing 6 materials such as stainless steel or heat-resistant alloys. The weld formation is aesthetically pleasing, with a low defect rate, facilitating rapid verification of the overall sealing performance of the device via helium mass spectrometry leak detection or gas pressure leak detection.

[0041] The testing apparatus and method for leak testing of turbocharger metal seals are as follows: This embodiment provides a test device and method for testing the leakage of metal seal rings of turbochargers, which is applicable to situations where the pressing surface of the turbocharger to be tested is not equipped with a heat insulation cover structure.

[0042] 1. Structure of each component of the device 1) Simplified turbine box 1 The simplified turbine housing 1 is a rotating structure, including a straight pipe section 11 at the top and a lower end flange 12 at the bottom.

[0043] The straight section pipe 11 has a circular pipe structure, and its inlet end is equipped with an inlet flange 13 for connecting to the air supply pipe of the turbocharger test bench via the flange. The inner diameter of the straight section pipe 11 is consistent with the inner diameter of the inlet flow channel of the turbocharger turbine housing under test to ensure the consistency of airflow.

[0044] Multiple sensor holes 111 are evenly distributed circumferentially on the inlet end wall of the straight section of pipe 11. In this embodiment, there are two sensor holes 111, located at both ends of the diameter of the straight section of pipe 11, near the inlet flange 13. The sensor holes 111 are threaded holes used to install temperature and pressure sensors to monitor the temperature and pressure of the gas entering the device in real time during the test.

[0045] The lower end flange 12 is located at the lower end of the straight section of pipe 11, and its lower end face is provided with a positioning stop structure inner stop 121. The inner stop 121 is an annular recessed groove that extends from the inner circumference of the lower end flange 12 towards the center to form an annular step. The inner circumferential surface of the inner stop 121 is a positioning mating surface used to mate with the outer circumferential surface of the simplified bearing body 2 mating flange 21. The bottom surface of the inner stop 121 is an annular end face used to fit against the upper end face of the simplified bearing body 2 mating flange 21, forming part of the metal sealing ring clamping surface.

[0046] The lower end face of the flange 12 is located on the annular area outside the inner stop 121, and multiple threaded blind holes 122 are evenly distributed circumferentially. The number, distribution circle diameter, and hole diameter of the threaded blind holes 122 are consistent with the bolt holes on the lower end face of the turbine housing of the turbocharger under test, and are used to connect bolts 4.

[0047] The surface roughness of the bottom surface of the inner stop 121 is consistent with the roughness of the corresponding clamping surface of the turbine housing of the turbocharger under test (e.g., Ra1.6, Ra 3.2). The bottom surface of the inner stop 121 is a smooth plane, consistent with the turbocharger under test.

[0048] 2) Simplify bearing body 2 The simplified bearing body 2 is a rotating structure, including a docking flange 21 located at the top and a support base 22 located at the bottom.

[0049] The mating flange 21 is an annular flange structure extending radially outward from the upper end of the simplified bearing body 2. Its outer diameter is adapted to the inner diameter of the inner stop 121 on the lower end face of the simplified turbine housing 1, allowing the mating flange 21 to lie flat within the inner stop 121. The outer circumferential surface of the mating flange 21 and the inner circumferential surface of the inner stop 121 are clearance-fitted to ensure the coaxiality of the simplified turbine housing 1 and the simplified bearing body 2 after assembly.

[0050] The upper end face of the mating flange 21 is another part of the metal seal ring clamping surface, and its surface roughness is consistent with the corresponding clamping surface roughness of the turbocharger bearing housing under test. The upper end face of the mating flange 21 is provided with a metal seal ring mounting reference structure sealing groove 211, the structural dimensions of which are consistent with the turbocharger under test. The cross-sectional shape, depth, width, and bottom roughness of the sealing groove 211 are completely consistent with the corresponding sealing groove of the turbocharger bearing housing under test. When the mating flange 21 is inserted into the inner stop 121, the upper end face of the mating flange 21 fits against the bottom surface of the inner stop 121, forming a complete metal seal ring clamping surface.

[0051] The lower end face of the mating flange 21 is a flat annular pressing surface, which is used to fit against the upper end face of the pressure plate 5.

[0052] The support base 22, located below the mating flange 21, is a cylindrical structure used to support the entire device and mount it on the test bench. The outer circumferential surface of the support base 22 is a smooth cylindrical surface. The lower end face of the support base 22 forms a flat, tight sealing surface with the bottom surface of the outer shell 6.

[0053] 3) Metal sealing ring 3 The metal sealing ring 3 is the test piece. It is a ring-shaped metal sealing element whose material, cross-sectional shape, and dimensions are consistent with the metal sealing ring used in the turbocharger under test. It is installed in the sealing groove before the test and removed for inspection afterward. The metal sealing ring 3 is installed in the sealing groove 211 on the upper end face of the flange 21 of the simplified bearing body 2. Its axial and radial positions are the same as those in the turbocharger under test.

[0054] 4) Pressure plate 5 The pressure plate 5 is an annular flat plate structure made of high-strength heat-resistant alloy steel. The diameter of the central hole of the pressure plate 5 is larger than the outer diameter of the simplified bearing body 2 support base 22, so that the pressure plate 5 can be fitted onto the support base 22 and press against the lower end face of the mating flange 21 (i.e., the bottom face of the mating flange 21 facing downwards). Multiple bolt through holes 51 are evenly distributed around the circumference of the pressure plate 5. The number, distribution circle diameter, and hole diameter of the bolt through holes 51 correspond one-to-one with the threaded blind holes 122 on the lower end face flange 12 of the simplified turbine housing 1.

[0055] 5) Bolt 4 Bolt 4 is a high-strength heat-resistant bolt, and its specifications (thread diameter, pitch, length), strength grade, head shape, and quantity are completely consistent with the bolts used to clamp the turbine housing and bearing body in the turbocharger under test. Bolt 4 passes through the bolt through hole 51 on the pressure plate 5 from below and is screwed into the threaded blind hole 122 on the lower end flange 12 of the simplified turbine housing 1. After tightening, the pressure plate 5 presses upward against the lower end face of the mating flange 21, so that the upper end face of the mating flange 21 is pressed tightly against the bottom surface of the inner stop 121.

[0056] 6) Outer shell 6 The outer shell 6 is a cylindrical structure made of rolled and welded low-carbon steel sheet. The outer shell 6 is fitted onto the outside of the pressure plate 5 and bolt 4, forming a sealed space surrounding the installation area of ​​the pressure plate 5, bolt 4 and metal sealing ring 3.

[0057] The upper end of the outer casing 6 is an open end, and the inner diameter of the opening is slightly larger than the outer diameter of the lower end flange 12 of the simplified turbine housing 1. A welded annular surface 7 is formed between the upper end surface of the outer casing 6 and the outer circumferential surface of the lower end flange 12 of the simplified turbine housing 1. The welded annular surface 7 is an annular mating surface, and is fully welded and sealed by argon arc welding.

[0058] The lower end of the outer casing 6 is a closed end, and the diameter of the central hole on the lower end face is slightly larger than the outer diameter of the support base 22, allowing the outer casing 6 to be fitted onto the support base 22. The bottom surface of the outer casing 6 is pressed against the lower end face of the simplified bearing body 2 support base 22, forming the first mechanical seal. A measuring hole 61 is provided on the circumferential wall of the outer casing 6, near the installation position of the metal sealing ring 3. The measuring hole 61 is a through hole, communicating with the sealed cavity formed by the outer casing 6, the simplified turbine housing 1, and the simplified bearing body 2, and is used to connect leakage measurement equipment (such as a gas flow meter, mass spectrometer, or differential pressure sensor) to measure the leakage rate or cumulative leakage of the metal sealing ring 3 during the high temperature and high pressure test.

[0059] The outer wall of the outer casing 6 has a stepped structure from top to bottom, meaning the outer diameter of the outer casing 6 gradually decreases from top to bottom, forming multiple steps. In this embodiment, the outer wall of the outer casing 6 forms three steps from top to bottom: the first step 62 is located at the upper part of the outer casing 6 and has the largest outer diameter; the second step 63 is located in the middle of the outer casing 6 and has a smaller outer diameter than the first step 62; the third step 64 is located at the lower part of the outer casing 6 and has the smallest outer diameter. The steps are connected by arc transitions. This stepped structure facilitates segmented cutting along the steps after testing, allowing the outer casing 6 to be disassembled in sections without damaging the internal components of the outer casing 6.

[0060] 2. Assembly and Testing Methods for the Device Step S1: Confirm the consistency of the pressing surface Based on the clamping surface structure of the turbocharger under test, a simplified turbine housing 1 and a simplified bearing housing 2 are selected. It is confirmed that the structural dimensions, inner circumferential surface roughness, and bottom surface roughness of the inner stop 121 on the lower end face of the simplified turbine housing 1 are consistent with the turbine housing clamping surface of the turbocharger under test; it is confirmed that the distribution of the threaded blind holes 122 located outside the inner stop 121 on the lower end face of the simplified turbine housing 1 is consistent with that of the turbocharger under test; it is confirmed that the outer diameter, upper end surface roughness, and sealing groove 211 dimensions of the mating flange 21 of the simplified bearing housing 2 are consistent with the bearing housing clamping surface of the turbocharger under test.

[0061] Step S2: Install metal sealing ring 3 Install the metal seal ring 3 into the sealing groove 211 on the upper end face of the flange 21 of the simplified bearing body 2, ensuring that the axial and radial positions of the metal seal ring 3 are exactly the same as the installation positions in the turbocharger under test. Check the fit clearance between the metal seal ring 3 and the sealing groove 211 to ensure that it is consistent with the fit condition in the turbocharger under test.

[0062] Step S3: Installation of pressure plate 5 and bolt 4 and control of preload force Insert the mating flange 21 of the simplified bearing housing 2 into the inner stop 121 on the lower end face of the simplified turbine housing 1, so that the upper end face of the mating flange 21 is in contact with the bottom surface of the inner stop 121. Place the pressure plate 5 onto the support base 22, so that the upper end face of the pressure plate 5 is in contact with the lower end face of the mating flange 21. Pass the bolt 4 through the corresponding bolt through hole 51 on the pressure plate 5 from below, and screw it into the corresponding threaded blind hole 122 on the annular area on the lower end face of the simplified turbine housing 1 located outside the inner stop 121. Using a calibrated torque wrench, tighten the bolt 4 according to the installation sequence and tightening torque specified for the turbocharger under test (e.g., tighten in two stages, the first pre-tightening to 50% of the specified torque, and the second tightening to 100% of the specified torque). During the tightening process, a diagonal cross sequence is used to ensure that the pressure plate 5 is subjected to uniform force, so that the upper end face of the mating flange 21 is evenly pressed against the bottom face of the inner stop 121, thereby enabling the metal sealing ring 3 to obtain the same preload and compression as in the turbocharger under test.

[0063] Step S4: Install and weld the outer casing 6. The outer casing 6 is fitted onto the outside of the pressure plate 5 and bolts 4 from top to bottom, so that the bottom surface of the outer casing 6 is pressed tightly against the lower end face of the simplified bearing body 2 support base 22. The position of the outer casing 6 is adjusted so that a welded annular surface 7 of uniform width is formed between the upper end face of the outer casing 6 and the outer peripheral surface of the lower end face flange 12 of the simplified turbine housing 1.

[0064] Clean the welding ring surface 7 to remove oil, oxide layer, and burrs. Perform argon arc welding along the entire circumference of the welding ring surface 7 to form a continuous and dense sealed weld. After welding, allow the weld to cool to room temperature, and then use a helium mass spectrometer leak detector to check for leaks, verifying that there are no other leak points besides sensor hole 111 and measuring hole 61. At this point, a sealed cavity is formed between the outer shell 6, the simplified turbine housing 1, and the simplified bearing body 2, communicating with the outside world only through measuring hole 61 and sensor hole 111.

[0065] Step S5: Bench testing and leak measurement The assembled test apparatus is mounted on the turbocharger test bench via inlet flange 13. The test bench is started, and high-temperature, high-pressure combustion gas (or simulated working fluid, such as compressed air or nitrogen) is introduced into the simplified turbine housing 1. The inlet temperature and pressure are monitored in real time through temperature and pressure sensors in sensor port 111 to ensure that the test conditions are consistent with the actual operating conditions of the turbocharger under test.

[0066] The leakage rate of the metal sealing ring 3 is measured in real time by a gas flow meter or mass spectrometer connected to the measuring port 61. Since the device has no other leakage channels besides the measuring port 61 and the sensor port 111, the measured leakage amount comes entirely from the sealing failure of the metal sealing ring 3 itself, eliminating interference from other leakage channels.

[0067] Step S6: Post-test disassembly and seal inspection After the specified test time or number of cycles is reached, the test bench is stopped. Once the device has cooled to a safe temperature, it is cut into sections along the stepped outer wall of the outer shell 6. First, the transition area between the first step 62 and the second step 63 on the upper part of the outer shell 6 is cut, and the upper section of the outer shell 6 is removed; then, the transition area between the second step 63 and the third step 64 is cut, and the middle section of the outer shell 6 is removed; finally, the lower section of the outer shell 6 is removed. Sectional cutting avoids deformation of the outer shell 6 during overall cutting, which could cause compression damage to the internal components.

[0068] After the outer casing 6 is completely removed, loosen and remove bolts 4 in a diagonal sequence, and remove pressure plate 5. Remove metal seal ring 3 from the sealing groove 211 of simplified bearing body 2. Perform the following checks on metal seal ring 3: Visual inspection: Observe the surface of the metal sealing ring 3 for cracks, scratches, ablation or plastic deformation; Dimensional measurement: Measure the cross-sectional height, width, and free diameter of the metal sealing ring 3, compare them with the dimensions before the test, and evaluate the amount of compression set; Microscopic analysis: The wear morphology and microcracks of the sealing surface of the metal sealing ring 3 were observed by scanning electron microscopy (SEM), and the surface elemental changes were detected by energy dispersive spectroscopy (EDS) to assess the degree of high-temperature oxidation or corrosion. Hardness test: Measure the hardness at different locations on the metal sealing ring 3 to assess the degree of softening or hardening at high temperatures.

[0069] Through the above inspections, a correlation between leakage rate data and seal ring damage status is established, providing data support for the optimized design, material selection, and life prediction of metal seal ring 3.

[0070] 3. Adaptability description of the structure with heat shield The present invention is also applicable when the pressure surface of the turbocharger under test is equipped with a heat shield structure. In this case, it is only necessary to add a heat shield with the same structural dimensions as the turbocharger under test to the bottom surface of the inner stop 121 of the simplified turbine housing 1 or the upper end surface of the mating flange 21 of the simplified bearing body 2. The material, thickness, shape, installation position, and fixing method of the heat shield are consistent with those of the turbocharger under test. After adding the heat shield, the installation position of the metal sealing ring 3, the assembly method of the pressure plate 5 and bolts 4, the installation and welding sealing method of the outer shell 6, and the steps of the test method are all the same as in this embodiment, and will not be repeated here.

[0071] The above description is merely a detailed account of one embodiment of the present invention, but it is only a preferred embodiment and should not be considered as limiting the scope of the invention. All equivalent variations and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A device for testing leakage of metal seals in turbochargers, characterized in that: This includes a simplified turbine housing, simplified bearing housing, bolts, pressure plates, and outer casing. The simplified turbine housing and the simplified bearing body are mated to form a metal sealing ring clamping surface. The sealing end face structure dimensions, surface roughness, and metal sealing ring installation position of the clamping surface are consistent with those of the turbocharger under test. If the clamping surface of the turbocharger under test is provided with a heat shield structure, then the clamping surface is provided with a heat shield of the same structure and dimensions as the turbocharger under test. If the clamping surface of the turbocharger under test is not provided with a heat shield structure, then the simplified turbine housing and the simplified bearing body directly constitute the clamping surface. The installation position of the metal sealing ring is consistent with the installation position in the turbocharger under test; The bolts and the pressure plate are assembled according to the installation requirements of the turbocharger under test, and the bolt tightening torque is the same as the installation torque of the turbocharger under test, to ensure that the preload of the metal sealing ring is consistent with the preload in the turbocharger under test; The outer casing has a measuring hole on its side for measuring the leakage rate or leakage amount of the metal sealing ring. The outer casing is fitted on the outside of the pressure plate and the bolt, and its bottom is pressed tightly against the simplified bearing body. The junction of the outer casing and the simplified turbine box forms a welded annular surface, and a seal is achieved by welding, thus forming a sealed cavity with no other leakage channels except for the measuring point. The simplified turbine housing has sensor holes on its straight section of pipe for measuring inlet temperature and pressure.

2. The turbocharger metal seal leakage testing device according to claim 1, characterized in that: The outer wall of the outer shell has a stepped structure from top to bottom, which facilitates cutting and disassembly after testing.

3. The turbocharger metal seal leakage testing device according to claim 1, characterized in that: The welding annular surface is the annular mating surface formed between the upper end face of the outer shell and the outer peripheral surface of the simplified turbine housing. After welding, it forms a full-circumference sealed weld.

4. The turbocharger metal seal leakage testing device according to claim 1, characterized in that: The simplified turbine housing and the simplified bearing housing are provided with a positioning stop structure at their mating end faces. The positioning stop structure achieves radial positioning during assembly through cylindrical surface mating, which is used to ensure the coaxiality and end face parallelism of the two.

5. The turbocharger metal seal leakage testing device according to claim 4, characterized in that: The pressing surface is provided with a metal sealing ring mounting reference structure, which is located on the radial inner side of the positioning stop structure, and its structural dimensions are consistent with the turbocharger to be tested.

6. The turbocharger metal seal leakage testing device according to claim 1, characterized in that: The sensor holes are located at the inlet end of the simplified turbine housing straight section pipeline, and multiple holes are evenly distributed along the circumference of the pipeline.

7. The turbocharger metal seal leakage testing device according to claim 1, characterized in that: The measuring hole is located on the side of the outer casing near the metal sealing ring and is connected to the sealed cavity.

8. The turbocharger metal seal leakage testing device according to claim 1, characterized in that: The welding ring is welded around the entire circumference using argon arc welding or laser welding.

9. The test method of the turbocharger metal seal leakage test device according to claim 1, characterized in that: Includes the following steps: S1: Based on the clamping surface structure of the turbocharger to be tested, select a simplified turbine housing and simplified bearing body with or without a heat shield to ensure that the structural dimensions, roughness, and sealing ring installation position of the clamping surface are consistent with the turbocharger to be tested. S2: Install the metal sealing ring in the same position as the turbocharger to be tested; S3: Install the pressure plate and bolts, and tighten the bolts according to the installation torque of the turbocharger to be tested, so that the metal seal rings obtain the same preload force as in the turbocharger to be tested; S4: The outer casing is fitted onto the outside of the pressure plate and bolts, so that the bottom of the outer casing is pressed against the simplified bearing body, and the welded annular surface at the junction of the outer casing and the simplified turbine box is welded and sealed to form a sealed cavity with no leakage channels except for the measuring hole and sensor hole; S5: Install the assembled test device on the turbocharger test bench, measure the inlet temperature and pressure through the sensor hole, and measure the leakage rate or leakage amount of the metal seal through the measuring hole; S6: After the test, cut along the stepped outer wall of the shell, remove the shell, then remove the bolts and pressure plate, and take out the metal sealing ring for damage inspection.

10. The test method of the turbocharger metal seal leakage test device according to claim 9, characterized in that: In step S4, the welding ring surface is cleaned before welding, and after welding, helium mass spectrometry or gas pressure leak detection is used to verify that there are no other leak points except for the measuring hole and sensor hole.

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