A turbocharger with a pressure-adaptive gas channel control device

Abstract

This invention discloses a turbocharger with a pressure-adaptive gas channel control device, relating to the field of turbocharger technology. It includes a rotor shaft, a control valve core, and an elastic element. The rotor shaft has an axially oriented gas channel, comprising a first channel at the compressor end and a second channel connected to the first channel and extending to the turbine end. The first channel communicates with the gas at the impeller back, and the second channel communicates with the region at the turbine back. The cross-sectional area of ​​the second channel is larger than that of the first channel. The control valve core is at least partially axially slidably disposed within the first channel. The control valve core includes a first piston structure for sealing the first channel. One end of the elastic element is connected to the end wall of the first channel opposite to the second channel, and the other end is connected to the control valve core. This design improves the thermal fatigue failure of turbine end components caused by high temperatures while preventing backflow of high-temperature exhaust gas and improving the compressor end sealing performance.

Description

Technical Field

[0001] This invention relates to the field of turbocharger technology, and in particular to a turbocharger with a pressure-adaptive gas channel control device. Background Technology

[0002] A turbocharger uses the energy of exhaust gases from an engine to drive a turbine, which in turn rotates a coaxial compressor impeller, compressing more air and sending it into the engine. It is a core component for improving engine power and reducing fuel consumption and emissions. The turbocharger's rotor shaft operates for extended periods in high-temperature, high-speed, and high-vibration environments.

[0003] An existing structure for reducing the temperature of the turbine rotor back of a turbocharger involves opening a fixed, through-type gas channel along the axial direction inside the rotor shaft. The inlet of the channel is located at the back of the compressor impeller, and the outlet passes through the turbine and connects to the outside. The low-temperature gas at the back of the compressor impeller flows directly to the turbine back and turbine outlet through this fixed channel to cool the turbine back and improve the problem of thermal fatigue failure of turbine end components caused by high temperature.

[0004] However, when the engine is operating at low speed and low load, the gas pressure at the compressor end is low, and the fixed channel cannot be actively closed, resulting in continuous gas loss at the compressor end. It is difficult to maintain the gas pressure required for sealing, causing oil leakage at the compressor end. Under certain operating conditions, such as when the engine is under exhaust braking, the gas pressure at the turbine end exceeds the gas pressure at the compressor end, and high-temperature exhaust gas can enter the compressor end in reverse through the fixed channel, causing intake air pollution and a decrease in boosting efficiency.

[0005] Therefore, how to prevent backflow of high-temperature exhaust gas while improving the thermal fatigue failure of turbine end components caused by high temperature, and improving the sealing performance of the compressor end, is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a turbocharger with a pressure adaptive gas channel control device, which improves the thermal fatigue failure of turbine end components caused by high temperature, blocks the backflow of high temperature exhaust gas, and improves the sealing performance of the compressor end.

[0007] To achieve the above objectives, the present invention provides a turbocharger with a pressure adaptive gas channel control device, comprising: The rotor shaft has a gas passage along the axial direction. The gas passage includes a first passage located at the compressor end and a second passage connected to the first passage and extending to the turbine end. The first passage is connected to the gas at the back of the impeller, and the second passage is connected to the area at the back of the turbine. The cross-sectional area of ​​the second passage is larger than that of the first passage. The control valve core is at least partially axially slidable within the first channel. The control valve core includes a first piston structure whose outer diameter matches the inner diameter of the first channel to seal the first channel. The elastic element has one end connected to the end wall of the first channel away from the second channel, and the other end connected to the control valve core. The control valve core has a first position and a second position. In the first position, the first piston structure is kept in the first channel to block the connection between the first channel and the second channel. In the second position, the control valve core moves towards the turbine end under the action of the gas pressure at the compressor end, overcoming the elastic force of the elastic element, so that the first piston structure enters the second channel. The first channel and the second channel are connected through the gap between the outer periphery of the first piston structure and the inner wall of the second channel.

[0008] In one possible implementation, the control valve core further includes a second piston structure, which is spaced apart from the first piston structure and located on the side of the first piston structure closer to the compressor end. The outer diameter of the second piston structure matches the inner diameter of the first channel, and at least one axially penetrating guide hole is provided on the second piston structure.

[0009] In one possible implementation, the first piston structure and the second piston structure are connected by a shaft, the outer diameter of which is smaller than the inner diameter of the first channel, so as to form an annular space between the outer wall of the shaft and the inner wall of the first channel, and the guide hole communicates with the annular space.

[0010] In one possible implementation, a shaft seal is also included, which is sleeved on the rotor shaft. The rotor shaft has a first radial opening that communicates with and extends radially from the first channel. The shaft seal has a first annular groove that communicates with the first radial opening and a first vent hole that communicates with the first annular groove and the gas at the back of the impeller.

[0011] In one possible implementation, the rotor shaft is further provided with a second radial opening that communicates with and extends radially from the first channel, and the shaft seal is provided with a second annular groove that communicates with the second radial opening, and a second vent hole that communicates with the second annular groove and extends to the outer circumference of the shaft seal.

[0012] In one possible implementation, a third annular groove is provided on the outer peripheral surface of the shaft seal, the third annular groove is connected to the second vent hole, and an elastic sealing film is provided at the third annular groove.

[0013] In one possible implementation, the inner wall of the first channel is provided with an inwardly protruding limiting protrusion that can abut against the second piston structure to restrict the movement of the second piston structure toward the compressor end.

[0014] In one possible implementation, the second channel has an enlarged section at one end near the first channel, and the inner radial direction of the enlarged section gradually increases away from the first channel.

[0015] In one possible implementation, there are multiple guide holes, which are uniformly arranged along the circumference of the second piston structure.

[0016] In one possible implementation, there are multiple first vent holes, which are evenly arranged along the circumference of the shaft seal. And / or, there are multiple second vent holes, which are evenly arranged along the circumference of the shaft seal.

[0017] Compared with the prior art, the technical solution provided by the present invention has at least the following beneficial effects: Specifically, the gas passage inside the rotor shaft is composed of a first channel with a smaller cross-sectional area and a second channel with a larger cross-sectional area. The control valve core is at least partially axially slidable in the first channel and is provided with a first piston structure that seals the first channel. One end of the elastic element is connected to the end wall of the first channel away from the second channel, and the other end is connected to the control valve core. Thus, when the gas pressure at the compressor end is insufficient to overcome the elastic force of the elastic element, the first piston structure remains within the first channel, blocking gas flow and preventing gas loss from the compressor end, thereby improving the compressor end sealing performance. Once the gas pressure at the compressor end increases and overcomes the elastic force, the first piston structure enters the second channel with a larger cross-section. A gap naturally forms between the outer periphery of the first piston structure and the inner wall of the second channel, opening the gas passage and enabling the delivery of cooling gas to the turbine end. This cools the heated areas of the turbine end, mitigating the problem of thermal fatigue failure of turbine end components due to high temperatures. The opening of this gas passage reduces the pressure difference between the compressor end and the turbine end, balancing the axial force and preventing excessive axial force fluctuations during operating condition switching that could lead to thrust bearing overload failure. When the turbine end gas pressure reverses, this reverse pressure pushes the first piston structure back towards the compressor end, ensuring that the first piston structure remains sealed within the first channel, thus preventing the backflow of high-temperature exhaust gas. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of the turbocharger provided in an embodiment of the present invention; Figure 2 This is a partial enlarged view of the turbocharger provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the shaft seal provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the control valve core provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the control valve core provided in an embodiment of the present invention from another perspective; Figure 6 This is a schematic diagram of the structure of the elastic sealing film provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the rotor shaft provided in an embodiment of the present invention; Figure 8 This is a schematic diagram of the structure when the first channel and the second channel are connected, as provided in an embodiment of the present invention; Figure 9 This is a schematic diagram of the structure when the first channel and the second channel are not connected, as provided in an embodiment of the present invention.

[0020] in: 101-Compressor housing; 102-Turbine housing; 103-Heat shield; 110-Impeller; 120-Rotor shaft; 121-First radial opening; 123-First channel; 124-Second radial opening; 125-Second channel; 126-Third radial opening; 127-Limiting protrusion; 130-Sealing ring seat; 140-Intermediate housing; 141-Intermediate housing volute end sealing ring mating surface; 142-Through hole; 150-Turbine; 151-Turbine wheel back; 160-Volute end sealing ring; 170-Thrust bearing; 180-Shaft seal; 181-First vent hole; 182-First annular groove; 184-Second annular groove; 185-Second vent hole; 186-Third annular groove; 190-Pressure end sealing ring; 210-Elastic element; 220-Control valve core; 221-Guide hole; 222-Shaft; 223-First piston structure; 224-Second piston structure; 226-First end face; 227-Second end face; 230-Elastic sealing membrane; 240-Annular space. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left" and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the position 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 of this invention.

[0024] The purpose of this invention is to provide a turbocharger with a pressure adaptive gas channel control device, which improves the thermal fatigue failure of turbine end components caused by high temperature, blocks the backflow of high temperature exhaust gas, and improves the sealing performance of the compressor end.

[0025] Please see Figures 1 to 9 To achieve the above objectives, the present invention provides a turbocharger with a pressure-adaptive gas channel control device, comprising a compressor housing 101, a turbine housing 102, a heat shield 103, an impeller 110, a sealing ring seat 130, an intermediate housing 140, a turbine 150, a turbine end sealing ring 160, a thrust bearing 170, a shaft seal 180, and a pressure end sealing ring 190. The turbocharger also includes a rotor shaft 120, a control valve core 220, and an elastic element 210. The rotor shaft 120 and the turbine 150 can be welded together, for example, using electron beam welding or laser welding. The turbocharger utilizes exhaust gas from the engine to drive the turbine 150. The turbine inlet pressure P2 refers to the exhaust gas pressure before it enters the turbine housing 102. The turbine 150 drives the coaxial impeller 110 to compress more air into the engine. The exhaust outlet pressure P1 refers to the air pressure after compression by the compressor and before it enters the engine, thereby enabling more fuel to burn completely, increasing engine power, and reducing harmful emissions. Generally, the pressure after the turbocharger is greater than the pressure before the turbocharger, and the difference between the two pressures gradually increases with engine speed. The magnitude and difference between the pressures after the turbocharger and before the turbocharger are closely related to the engine's operating conditions and turbocharger matching. Of course, there are also certain operating conditions where the pressure before the turbocharger is greater than the pressure after the turbocharger.

[0026] The rotor shaft 120 has a gas passage along its axial direction. The rotor shaft 120 includes a compressor end and a turbine end. The gas passage includes a first passage 123 located at the compressor end and a second passage 125 connected to the first passage 123 and extending to the turbine end. The first passage 123 communicates with the gas at the back of the impeller 110, and the second passage 125 communicates with the area at the back of the turbine 151. The cross-sectional area of ​​the second passage 125 is larger than that of the first passage 123. The control valve core 220 is at least partially axially slidable. The control valve core 220, located within the first channel 123, includes a first piston structure 223. The outer diameter of the first piston structure 223 matches the inner diameter of the first channel 123. The first piston structure 223 seals the first channel 123. The control valve core 220 can be made of the same material as the rotor shaft 120 to ensure dynamic balance during high-speed rotation. The surface of the control valve core 220 is nitrided or vacuum-coated with chromium aluminum silicon nitride, achieving a surface hardness of not less than 1000 HV and a surface roughness of not more than Ra 0.4 μm, thus improving wear resistance and sealing performance. A high-precision gap seal is used between the first piston structure 223 and the first channel 123, which can be, but is not limited to, spherical seals or stepped seals. One end of the elastic element 210 is connected to the end wall of the first channel 123 facing away from the second channel 125, and the other end is connected to the control valve core 220. The elastic element 210 can be made of high-temperature alloy materials such as wave springs, disc springs, or elastic diaphragms to meet the requirements of high-temperature durability and reset accuracy.

[0027] The control valve core 220 has a first position and a second position. In the first position, the first piston structure 223 is held in the first channel 123 to block the communication between the first channel 123 and the second channel 125. In the second position, the control valve core 220 moves towards the turbine end under the action of the compressor end gas pressure, overcoming the elastic force of the elastic element 210, so that the first piston structure 223 enters the second channel 125. The first channel 123 and the second channel 125 are connected through the gap between the outer periphery of the first piston structure 223 and the inner wall of the second channel 125.

[0028] The gas passage within the rotor shaft 120 consists of a first passage 123 with a smaller cross-sectional area and a second passage 125 with a larger cross-sectional area. The control valve core 220 is at least partially axially slidable within the first passage 123 and is equipped with a first piston structure 223 that seals the first passage 123. One end of the elastic element 210 is connected to the end wall of the first passage 123 facing away from the second passage 125, and the other end is connected to the control valve core 220. Thus, when the compressor-end gas pressure is insufficient to overcome the elastic force of the elastic element 210, the first piston structure 223 remains within the first passage 123, blocking gas flow, preventing compressor-end gas loss, and improving compressor-end sealing performance. When the engine enters medium-high speed, high-load operating conditions, the turbocharger speed increases, and the compressor-end gas pressure increases. After the compressor-end gas pressure increases and overcomes the elastic force, the first piston structure 223 enters the second passage 125 with a larger cross-section. A gap naturally forms between the outer periphery of the first piston structure 223 and the inner wall of the second passage 125, opening the gas passage. This system delivers cooling gas to the turbine end to cool the heated areas, mitigating thermal fatigue failure of turbine components caused by high temperatures. The opening of this gas channel reduces the pressure difference between the compressor and turbine ends, balancing the axial force and preventing excessive axial force fluctuations during operating condition changes that could lead to overload failure of the thrust bearing 170. The axial force refers to the force generated along the axial direction due to asymmetrical aerodynamic loads on both sides of the impeller 110 and turbine 150 during high-speed operation. This axial force is primarily borne by the thrust bearing 170. The axial force of the turbocharger is the resultant force of the axial force at the compressor end and the turbine end. When the turbine end gas pressure reverses, this reverse pressure pushes the first piston structure 223 back towards the compressor end, ensuring that the first piston structure 223 remains sealed within the first channel 123, thus preventing backflow of high-temperature exhaust gas.

[0029] In one possible implementation, the control valve core 220 further includes a second piston structure 224, which is spaced apart from the first piston structure 223 and located on the side of the first piston structure 223 closer to the compressor end. The outer diameter of the second piston structure 224 matches the inner diameter of the first channel 123, and at least one axially penetrating guide hole 221 is provided on the second piston structure 224. A clearance fit is formed between the second piston structure 224 and the inner wall of the first channel 123, serving as auxiliary guide and auxiliary sealing. The axially penetrating guide hole 221 allows compressor-end gas to enter the area between the first piston structure 223 and the second piston structure 224 via the guide hole 221, providing a gas passage for the pneumatically driven control valve core 220 to move. The matching of the outer diameter of the second piston structure 224 with the inner diameter of the first channel 123 ensures that the control valve core 220 remains axially aligned during sliding, while reducing radial gas leakage. In another possible implementation, the guide hole 221 can also be configured as a groove-shaped structure formed on the outer peripheral surface of the second piston structure 224. When there are multiple guide holes 221, the multiple guide holes 221 are evenly arranged along the circumference of the second piston structure 224 to ensure uniform gas flow in the circumference, and at the same time, it is beneficial to control the dynamic balance of the valve core 220 when it rotates at high speed.

[0030] In one possible implementation, the first piston structure 223 and the second piston structure 224 are connected by a shaft 222. The outer diameter of the shaft 222 is smaller than the inner diameter of the first channel 123, so as to form an annular space 240 between the outer wall of the shaft 222 and the inner wall of the first channel 123. A guide hole 221 communicates with the annular space 240, and gas from the compressor end can enter the annular space 240 through the guide hole 221. The side of the second piston structure 224 facing away from the first piston structure 223 is the first end face 226, and the surface area of ​​the first end face 226 is S1. The side of the first piston structure 223 facing away from the second piston structure 224 is the second end face 227, and the surface area of ​​the second end face 227 is S2. When the gas pressure (P) at the impeller 110 back is... cb The driving force applied to the first end face 226 is greater than the restoring force corresponding to the spring elongation (L1) and the gas pressure (P) at the turbine back 151. tb When the sum of the driving forces applied to the second end face 227 (i.e., P) cb ·S1>k·L1+P tb ·S2, where k is the spring constant), the gas pressure at the back of impeller 110 (P) cb The driving force applied to the first end face 226 drives the control valve core 220 to move along the axis toward the turbine end, and the spring elongation gradually increases (e.g., the spring elongation is greater than L1 by L2). When the gas pressure at the back of the impeller 110 (P)cb The driving force applied to the first end face 226 is equal to the restoring force corresponding to the spring elongation (L2) and the gas pressure (P) at the turbine back 151. tb When the driving force (i.e. P) is applied to the second end face 227, cb S1 = k·L2 + P tb (S2) The control valve core 220 is in a relatively stable state.

[0031] Under certain engine operating conditions, when the gas pressure (P) at the back of impeller 110... cb The driving force applied to the first end face 226 is less than the gas pressure at the turbine back 151 (P). tb When the driving force applied to the second end face 227 and the spring restoring force (such as the spring elongation being L2) are equal (i.e., P) cb ·S1<k·L2+P tb ·S2), gas pressure at 151 on the turbine back (P) tb This will push the control valve core 220 to move along the axis toward the compressor end, and at P cb ·S1=P tb • S2 ensures the spring is in its fully reset state. If the spring is fully reset, the gas pressure (P) at the back of impeller 110 is... cb The driving force applied to the first end face 226 is still less than the gas pressure at the turbine back 151 (P). tb The driving force applied to the second end face 227 will increase the gas pressure (P) at the turbine back 151. tb The drive control valve core 220 will continue to move along the axis towards the compressor end, and the spring will be compressed (e.g., the compression of the spring is L3) until the gas pressure at the back of the impeller 110 (P) continues to increase. cb The sum of the driving force applied to the first end face 226 and the restoring force corresponding to the spring compression deformation (e.g., the spring compression is L3) equals the gas pressure (Ptb) at the turbine back 151 when the driving force applied to the second end face 227 (i.e., P) is equal to the gas pressure (Ptb) at the turbine back 151. cb ·S1+k·L3=P tb (S2) The control valve core 220 is in a relatively stable state.

[0032] In one possible implementation, the inner wall of the first channel 123 is provided with an inwardly protruding limiting protrusion 127. The limiting protrusion 127 can abut against the second piston structure 224 to restrict the movement of the second piston structure 224 toward the compressor end. The limiting protrusion 127 is located on the side of the second piston structure 224 near the compressor end. Under certain specific operating conditions of the engine, when the gas pressure (P) at the turbine back 151 is... tb The gas pressure at the impeller back (P) is greater than that at the impeller 110. cbWhen the spring is compressed to a certain extent, the control valve core 220 is subjected to the gas pressure (P) at the turbine wheel back 151. tb The driving force applied to the second end face 227 pushes the first end face 226 to abut against the limiting protrusion 127, preventing the control valve core 220 from moving further towards the compressor end, avoiding excessive compression of the elastic element 210 leading to plastic deformation or failure, and ensuring that the first piston structure 223 can always remain sealed within the first channel 123. A buffer pad or buffer structure can be provided on the mating surface between the limiting protrusion 127 and the second piston structure 224 to reduce impact. The length of the shaft 222 or the axial thickness of the first piston structure 223 can be adjusted so that when the limiting protrusion 127 abuts against the second piston structure 224, the second radial opening 124 remains between the first piston structure 223 and the second piston structure 224.

[0033] In one possible implementation, the turbocharger further includes a shaft seal 180, which is sleeved on the rotor shaft 120 and can achieve gas sealing through an interference fit. The rotor shaft 120 has at least one first radial opening 121 that communicates with the first channel 123 and extends radially. The number of first radial openings 121 can be set as needed. The shaft seal 180 has a first annular groove 182 that communicates with the first radial opening 121 and a first vent hole 18 that communicates with the first annular groove 182 and the gas back of the impeller 110. 1. The first annular groove 182 is an annular groove extending circumferentially along the inner circumferential surface of the shaft seal 180, ensuring that it can communicate with each of the first radial openings 121. There are multiple first vent holes 181, which are evenly arranged along the circumference of the shaft seal 180. The gas at the back of the impeller 110 enters the first annular groove 182 through the first vent holes 181, and then enters the first channel 123 of the rotor shaft 120 through the first radial openings 121, thus realizing the stable introduction of gas at the back of the impeller 110 into the gas channel inside the rotor shaft 120.

[0034] Furthermore, the rotor shaft 120 is also provided with at least one second radial opening 124 that communicates with the first channel 123 and extends radially. The number of second radial openings 124 can be set as needed. The shaft seal 180 is provided with a second annular groove 184 that communicates with the second radial opening 124, and a second vent hole 185 that communicates with the second annular groove 184 and extends to the outer circumferential surface of the shaft seal 180. The second annular groove 184 is an annular groove that extends circumferentially along the inner circumferential surface of the shaft seal 180 to ensure that it can communicate with each of the second radial openings 124. There are multiple second vent holes 185. The gas at the back of the impeller 110 enters the first annular groove 182 through the first vent hole 181, and then enters the first channel 123 of the rotor shaft 120 through the first radial opening 121. When the second piston structure 224 is located between the first radial opening 121 and the second radial opening 124, that is, when the annular space 240 is connected to the second radial opening 124, the gas entering the first channel 123 can enter the second radial opening 124 through the guide hole 221 and the annular space 240, and then enter the second annular groove 184 and the second vent hole 185.

[0035] Furthermore, a third annular groove 186 is formed on the outer circumferential surface of the shaft seal 180. The third annular groove 186 is connected to the second vent hole 185. An elastic sealing diaphragm 230 is provided at the third annular groove 186. When the elastic sealing diaphragm 230 is inserted into the third annular groove 186, the inner diameter of the elastic sealing diaphragm 230 fits against the third annular groove 186. When gas enters the third annular groove 186 through the second vent hole 185, the gas pressure (P) at the back of the impeller 110 is... cb The driving elastic sealing diaphragm 230 expands and deforms radially, significantly reducing the radial clearance between the shaft seal 180 and the sealing ring seat 130, thus improving the compressor end sealing capability. The radial expansion deformation amount δ = P cb ·S3 / (E·t), where E is the elastic modulus of the elastic sealing film 230, t is the thickness of the elastic sealing film 230, and S3 is the contact area between the gas and the inner circumferential surface of the elastic sealing film 230. The elastic sealing film 230 can be made of high-temperature resistant rubber, fluororubber, or polytetrafluoroethylene composite film, and a fabric reinforcement layer can be added to it to improve tear resistance, high-temperature resistance, and service life. By controlling the thickness and material hardness of the elastic sealing film 230, the sealing gap under different gas pressures can be adjusted. The elastic sealing film 230 can also be replaced by an elastic lip seal or a deformable metal diaphragm, as long as the above objectives are achieved. In addition, a fourth annular groove is opened on the outer circumferential surface of the shaft seal 180, and a pressure end sealing ring 190 is installed on the fourth annular groove. The elastic sealing film 230 and the pressure end sealing ring 190 achieve both gas sealing and mechanical sealing, reducing the risk of oil leakage.

[0036] In one possible implementation, the second channel 125 has an expansion section at one end near the first channel 123. The inner radial direction of the expansion section gradually increases away from the first channel 123. The expansion section can have a conical transition or a circular arc transition. When the control valve core 220 moves towards the turbine end, the radial gap between the outer wall of the first piston structure 223 and the inner wall of the expansion section gradually increases, realizing the gradual opening of the gas channel and avoiding the pressure change caused by the instantaneous full opening of the channel. At the same time, the setting of the expansion section helps to guide the airflow smoothly into the second channel 125, reducing eddies and pressure loss. By accurately calculating and setting the spring extension, the outer peripheral surface of the second piston structure 224 is sealed to the second radial opening 124 of the rotor shaft 120. At the same time, the outer peripheral surface of the first piston structure 223 moves to the position of the expansion section, realizing the connection between the first channel 123 and the second channel 125. At this time, the low-temperature gas at the back of the impeller 110 enters the first annular groove 182 through the first vent hole 181 of the shaft seal 180 so as to enter the first radial opening 121 of the rotor shaft 120. Then it enters the first channel 123 and flows through the aforementioned guide hole 221 and annular space 240. After that, it flows between the outer peripheral surface of the first piston structure 223 and the inner wall of the expansion section, and continues to flow towards the turbine end through the second channel 125. During this process, the pressure end floating bearing, the volute end floating bearing, and the volute end sealing ring 1 of the rotor shaft 120 are cooled in sequence. At the mating point between rotor shaft 120 and impeller shaft 120, a third radial opening 126 is provided at the end of rotor shaft 120 near the turbine end. Gas passes through the third radial opening 126 to cool the volute end sealing ring 160, the volute end surface of rotor shaft 120, the mating surface 141 of intermediate shell volute end sealing ring, and the turbine back 151. Gas then enters the cavity that mates with heat shield 103 through the through hole 142 on intermediate shell 140 for further cooling. This achieves turbine end cooling while optimizing pressure distribution, i.e., reducing the gas pressure (P) at the impeller back 110. cb ) and the gas pressure at 151 on the turbine back (P) tb The difference in axial force can improve the reliability of the thrust bearing 170 and reduce power consumption, thereby improving the overall efficiency of the turbocharger.

[0037] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0038] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0039] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A turbocharger with a pressure-adaptive gas channel control device, characterized in that, include: The rotor shaft (120) has a gas passage along the axial direction. The gas passage includes a first passage (123) located at the compressor end and a second passage (125) connected to the first passage (123) and extending to the turbine end. The first passage (123) is connected to the gas at the back of the impeller (110), and the second passage (125) is connected to the area at the back of the turbine (151). The cross-sectional area of ​​the second passage (125) is larger than the cross-sectional area of ​​the first passage (123). A control valve core (220) is at least partially axially slidably disposed within the first channel (123). The control valve core (220) includes a first piston structure (223) whose outer diameter matches the inner diameter of the first channel (123) to seal the first channel (123). The elastic element (210) is connected at one end to the end wall of the first channel (123) away from the second channel (125) and at the other end to the control valve core (220). The control valve core (220) has a first position and a second position. In the first position, the first piston structure (223) is held in the first channel (123) to block the communication between the first channel (123) and the second channel (125). In the second position, the control valve core (220) moves towards the turbine end under the action of the gas pressure at the compressor end, overcoming the elastic force of the elastic element (210), so that the first piston structure (223) enters the second channel (125). The first channel (123) and the second channel (125) are connected through the gap between the outer periphery of the first piston structure (223) and the inner wall of the second channel (125).

2. The turbocharger with a pressure adaptive gas channel control device according to claim 1, characterized in that, The control valve core (220) further includes a second piston structure (224), which is spaced apart from the first piston structure (223). The second piston structure (224) is located on the side of the first piston structure (223) closer to the compressor end. The outer diameter of the second piston structure (224) matches the inner diameter of the first channel (123). At least one axially penetrating guide hole (221) is provided on the second piston structure (224).

3. The turbocharger with pressure adaptive gas channel control device according to claim 2, characterized in that, The first piston structure (223) and the second piston structure (224) are connected by a shaft (222). The outer diameter of the shaft (222) is smaller than the inner diameter of the first channel (123) to form an annular space (240) between the outer wall of the shaft (222) and the inner wall of the first channel (123). The guide hole (221) is connected to the annular space (240).

4. The turbocharger with pressure adaptive gas channel control device according to claim 2, characterized in that, It also includes a shaft seal (180), which is sleeved on the rotor shaft (120). The rotor shaft (120) has a first radial opening (121) that communicates with the first channel (123) and extends radially. The shaft seal (180) has a first annular groove (182) that communicates with the first radial opening (121) and a first vent hole (181) that communicates with the first annular groove (182) and the gas at the back of the impeller (110).

5. The turbocharger with a pressure adaptive gas channel control device according to claim 4, characterized in that, The rotor shaft (120) is also provided with a second radial opening (124) that communicates with the first channel (123) and extends radially. The shaft seal (180) is provided with a second annular groove (184) that communicates with the second radial opening (124) and a second vent hole (185) that communicates with the second annular groove (184) and extends to the outer circumference of the shaft seal (180).

6. The turbocharger with pressure adaptive gas channel control device according to claim 5, characterized in that, The outer circumferential surface of the shaft seal (180) is provided with a third annular groove (186), which is connected to the second vent hole (185). An elastic sealing film (230) is provided at the third annular groove (186).

7. The turbocharger with a pressure adaptive gas passage control device according to any one of claims 2 to 6, characterized in that, The inner wall of the first channel (123) is provided with an inwardly protruding limiting protrusion (127), which can abut against the second piston structure (224) to restrict the second piston structure (224) from moving toward the compressor end.

8. The turbocharger with a pressure adaptive gas passage control device according to any one of claims 1 to 6, characterized in that, The second channel (125) has an enlarged diameter section at one end near the first channel (123), and the inner radial direction of the enlarged diameter section gradually increases away from the first channel (123).

9. The turbocharger with a pressure adaptive gas passage control device according to any one of claims 2 to 6, characterized in that, There are multiple guide holes (221), and the multiple guide holes (221) are evenly arranged along the circumference of the second piston structure (224).

10. The turbocharger with a pressure-adaptive gas channel control device according to claim 5 or 6, characterized in that, There are multiple first vent holes (181), and the multiple first vent holes (181) are evenly arranged along the circumference of the shaft seal (180); And / or, there are multiple second vent holes (185), and the multiple second vent holes (185) are evenly arranged along the circumference of the shaft seal (180).

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