Crankshaft oil seal device, sealing control method, and engine

Abstract

The application discloses a crankshaft oil seal device, a sealing control method and an engine, and belongs to the technical field of engines.The crankshaft oil seal device comprises an oil seal structure and a flinger, the flinger is sleeved on a crankshaft, and a constant-pressure cavity is arranged between the flinger and the oil seal structure; a spiral structure is arranged on the side of the flinger away from the engine body, a first cavity is arranged between the spiral structure and the oil seal structure, and the first cavity is in communication with the constant-pressure cavity; wherein, in the case that the crankshaft drives the flinger to rotate, the pumping pressure in the first cavity and the pressure in the crankcase are in dynamic balance. Through the arrangement of the spiral structure, the pumping pressure generated by the spiral structure and the internal pressure of the crankcase reach dynamic balance in the first cavity, thereby preventing the oil-gas mixture in the crankcase from leaking to the outside, and the problem that the high-power engine is prone to oil leakage under high-speed working conditions is solved. Meanwhile, due to the non-contact structure between the oil seal structure and the flinger, the friction loss is reduced, and the service life of the crankshaft oil seal device is prolonged.

Description

Technical Field

[0001] This application relates to the field of engine technology, and in particular to a crankshaft oil seal device, a sealing control method, and an engine. Background Technology

[0002] The engine crankshaft is installed inside the crankcase. The crankshaft is a moving part, while the engine block and other components are fixed parts. The two are sealed at the engine output end through a non-contact oil seal structure. As the crankshaft rotates at high speed, a large amount of oil mist generated by splashed lubricating oil accumulates in the crankcase. A small portion of the high-temperature, high-pressure gases produced by combustion in the cylinders also enters the crankcase through the piston ring gaps, increasing the crankcase pressure. Due to the pressure difference between the inside and outside of the crankcase, the oil mist inside flows out of the engine along the gaps between the engine block and other fixed components and the crankshaft, resulting in oil leakage at the output end. This contaminates the engine itself and the engine compartment environment, and poses a safety risk. Summary of the Invention

[0003] This application provides a crankshaft oil seal device, a sealing control method, and an engine to at least partially solve the aforementioned technical problem of oil leakage at the crankcase output end.

[0004] To achieve the above objectives, according to a first aspect of this application, a crankshaft oil seal device is provided, disposed within a crankcase and connected to the engine block within the crankcase, for preventing leakage of media from the crankcase to the outside. The crankshaft oil seal device includes: Oil seal structure; An oil slinger is fitted onto the crankshaft, and there is a pressure stabilizing chamber between the oil slinger and the oil seal structure. A spiral structure is provided on the side of the oil slinger away from the engine body, and there is a first chamber between the spiral structure and the oil seal structure. The first chamber is connected to the pressure stabilizing chamber. In this process, when the crankshaft drives the oil slinger to rotate, the pumping pressure in the first chamber and the pressure in the crankcase are in dynamic equilibrium.

[0005] In some embodiments, when the medium in the first chamber is pure air, the pumping pressure in the first chamber is set to 0.25 to 0.5 times the pressure in the crankcase by setting the structural parameters of the spiral structure.

[0006] In some embodiments, the structural parameters of the helical structure include the tooth height, groove width, tooth width, helix angle, and helix angle direction of the helical groove.

[0007] In some embodiments, a second chamber is provided between the oil slinger and the oil seal structure. The second chamber is located on the side of the spiral structure closer to the body and is connected to the first chamber and the pressure stabilizing chamber, respectively.

[0008] In some embodiments, the oil slinger includes a plurality of first sealing teeth, and a second chamber is provided between two adjacent first sealing teeth.

[0009] In some embodiments, the oil seal structure includes a plurality of second sealing teeth, with a second chamber between the plurality of second sealing teeth.

[0010] In some embodiments, the oil slinger includes a plurality of first sealing teeth, and the oil seal structure includes a plurality of second sealing teeth, wherein the plurality of first sealing teeth and the plurality of second sealing teeth are respectively arranged opposite to each other in the radial direction of the crankshaft.

[0011] In some embodiments, the oil seal structure has an oil return channel that communicates with a second chamber and is used to guide the medium in the second chamber into the oil pan.

[0012] In some embodiments, the oil return channel has an oil return port for communicating with the oil pan.

[0013] In some embodiments, an oil baffle is provided on the side of the oil slinger near the machine body, and the oil baffle and the oil seal structure enclose a pressure stabilizing chamber.

[0014] In some embodiments, the oil seal structure includes a first oil seal portion and a second oil seal portion, which are respectively fixedly connected to the machine body by fasteners.

[0015] According to a second aspect of this application, a sealing control method for a crankshaft oil seal device is provided, applied to the aforementioned crankshaft oil seal device, the method comprising the following steps: The crankshaft drives the oil slinger to rotate; The spiral structure generates pumping pressure in the first chamber and keeps the pumping pressure in the first chamber in dynamic equilibrium with the pressure in the crankcase, thus preventing the medium in the crankcase from leaking out.

[0016] According to a third aspect of this application, an engine is also provided, comprising: The crankcase includes the engine block and the aforementioned crankshaft oil seal device, which is connected to the engine block.

[0017] The crankshaft oil seal device of this application embodiment includes an oil seal structure and an oil slinger. The oil slinger is sleeved on the crankshaft, and a pressure stabilizing chamber is provided between the oil slinger and the oil seal structure. A spiral structure is provided on the side of the oil slinger away from the engine body, and a first chamber is provided between the spiral structure and the oil seal structure. The first chamber is connected to the pressure stabilizing chamber. When the crankshaft drives the oil slinger to rotate, the pumping pressure in the first chamber is dynamically balanced with the pressure in the crankcase. The crankshaft oil seal device is installed on the crankcase output end of the engine through the engine body. Through the cooperation of the oil seal structure and the oil slinger, a non-contact sealing structure is formed at the crankshaft output end. The pressure stabilizing chamber serves to initially collect splashed lubricating oil. The spiral structure is located on the side of the oil slinger away from the engine body, forming the first chamber with the inner surface of the oil seal structure. During the rotation of the oil slinger driven by the crankshaft, the spiral structure utilizes the viscous force of the fluid to generate a pumping pressure towards the interior of the engine body. By employing a spiral structure, the pumping pressure generated by the spiral structure achieves a dynamic balance with the internal pressure of the crankcase within the first chamber, thereby preventing the oil-gas mixture in the crankcase from leaking to the outside and solving the problem of easy oil leakage under high-speed conditions in high-power engines. Simultaneously, the non-contact structure between the oil seal and the oil slinger reduces frictional losses and extends the service life of the crankshaft oil seal device.

[0018] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0021] Figure 1 This is a partial structural schematic diagram of the crankshaft oil seal device provided in an exemplary embodiment of this application; Figure 2 This is a cross-sectional view of the crankshaft oil seal device provided in an exemplary embodiment of this application; Figure 3 yes Figure 2 A partial structural diagram; Figure 4 This is a partial structural diagram of the oil seal structure provided in an exemplary embodiment of this application; Figure 5 This is a schematic diagram of the structure of the oil slinger provided in an exemplary embodiment of this application; Figure 6 This is a schematic diagram of the structure of the oil slinger provided in another exemplary embodiment of this application.

[0022] Explanation of reference numerals in the attached figures: 1. Crankcase; 2. Engine body; 3. Oil seal structure; 4. Oil slinger; 5. Crankshaft; 6. Pressure stabilizing chamber; 7. Spiral structure; 8. First chamber; 9. Second chamber; 10. Fastener; 30. Second sealing tooth; 31. Oil return channel; 32. First oil seal part; 33. Second oil seal part; 40. First sealing tooth; 41. Oil baffle; 310. Oil return port; 311. First channel; 312. Second channel; 313. Third channel. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0024] In related technologies, marine engine oil seal structures primarily employ contact-type lip seals and non-contact labyrinth seals. The engine crankshaft is installed within the crankcase; the crankshaft is a moving component, while the engine block and other components are fixed. A non-contact oil seal structure seals the engine output end. With the high-speed rotation of the crankshaft, a large amount of oil mist generated by splashed lubricating oil accumulates in the crankcase. A small portion of the high-temperature, high-pressure gas generated during combustion in the cylinders also enters the crankcase through the piston ring gaps, increasing the crankcase pressure. Due to the pressure difference between the inside and outside of the crankcase, the oil mist flows out along the gaps between the engine block and the crankshaft, resulting in oil leakage at the output end. This contaminates the engine itself and the engine room environment, posing a safety risk.

[0025] Contact-type lip seals typically install the lip seal at the junction of the crankshaft and oil seal for sealing. The lip seal consists of a rubber ring and a steel frame. The rubber ring directly contacts the crankshaft, preventing oil mist from leaking out of the crankcase. Due to the high-speed rotation of the crankshaft, the rubber seal gradually ages and requires periodic replacement. This is especially true in high-power engines where the linear velocity at the crankshaft edge is higher, leading to faster rubber aging and making replacement more difficult, thus failing to meet the requirements of high-power diesel engines. Contact-type lip seals are mainly used in small and medium-sized engines.

[0026] Traditional non-contact oil seals typically employ a single labyrinth structure, achieving a seal by setting different labyrinth structures between the oil seal and the oil slinger and controlling the gap between them. This structure can reduce lubricating oil leakage, but due to the labyrinth gaps and the pressure difference between the inside and outside of the crankcase, it cannot fundamentally solve the problem of oil leakage at the output end.

[0027] In view of this, this application provides a crankshaft 5 oil seal device including an oil seal structure 3 and an oil slinger 4. The oil slinger 4 is sleeved on the crankshaft 5, and a pressure stabilizing chamber 6 is provided between the oil slinger 4 and the oil seal structure 3. A spiral structure 7 is provided on the side of the oil slinger 4 away from the engine body 2, and a first chamber 8 is provided between the spiral structure 7 and the oil seal structure 3. The first chamber 8 is connected to the pressure stabilizing chamber 6. When the crankshaft 5 drives the oil slinger 4 to rotate, the pumping pressure in the first chamber 8 is in dynamic equilibrium with the pressure in the crankcase 1. The crankshaft 5 oil seal device is installed on the output end of the crankcase 1 of the engine through the engine body 2. Through the cooperation of the oil seal structure 3 and the oil slinger 4, a non-contact sealing structure is formed at the output end of the crankshaft 5. The pressure stabilizing chamber 6 plays a role in initially collecting splashed lubricating oil. The spiral structure 7 is provided on the side of the oil slinger 4 away from the engine body 2, and together with the inner surface of the oil seal structure 3, it forms the first chamber 8. As the crankshaft 5 drives the oil slinger 4 to rotate, the spiral structure 7 utilizes the viscous force of the fluid to generate a pumping pressure towards the interior of the engine block 2. Through the arrangement of the spiral structure 7, the pumping pressure generated by the spiral structure 7 achieves dynamic equilibrium with the internal pressure of the crankcase 1 within the first chamber 8, thereby preventing the oil-air mixture in the crankcase 1 from leaking to the outside and solving the problem of easy oil leakage under high-speed conditions in high-power engines. Simultaneously, the non-contact structure between the oil seal structure 3 and the oil slinger 4 reduces frictional losses and extends the service life of the crankshaft 5 oil seal device.

[0028] This application provides a crankshaft 5-oil seal device; please refer to [link / reference]. Figure 1 and Figure 2 , Figure 1 This is a partial structural schematic diagram of the crankshaft 5 oil seal device provided in an exemplary embodiment of this application; Figure 2This is a cross-sectional view of the crankshaft 5 oil seal device provided in an exemplary embodiment of this application. The crankshaft 5 oil seal device of this embodiment includes an oil seal structure 3 and an oil slinger 4. The oil slinger 4 is sleeved on the crankshaft 5, and a pressure stabilizing chamber 6 is provided between the oil slinger 4 and the oil seal structure 3. A spiral structure 7 is provided on the side of the oil slinger 4 away from the engine body 2. A first chamber 8 is provided between the spiral structure 7 and the oil seal structure 3, and the first chamber 8 is connected to the pressure stabilizing chamber 6. When the crankshaft 5 drives the oil slinger 4 to rotate, the pumping pressure in the first chamber 8 is in dynamic equilibrium with the pressure in the crankcase 1. The crankshaft 5 oil seal device is installed on the output end of the crankcase 1 of the engine through the engine body 2. Through the cooperation of the oil seal structure 3 and the oil slinger 4, a non-contact sealing structure is formed at the output end of the crankshaft 5. The pressure stabilizing chamber 6 plays a role in initially collecting splashed lubricating oil. The spiral structure 7 is provided on the side of the oil slinger 4 away from the engine body 2, and together with the inner surface of the oil seal structure 3, it forms the first chamber 8. As the crankshaft 5 drives the oil slinger 4 to rotate, the spiral structure 7 utilizes the viscous force of the fluid to generate a pumping pressure towards the interior of the engine block 2. Through the arrangement of the spiral structure 7, the pumping pressure generated by the spiral structure 7 achieves dynamic equilibrium with the internal pressure of the crankcase 1 within the first chamber 8, thereby preventing the oil-air mixture in the crankcase 1 from leaking to the outside and solving the problem of easy oil leakage under high-speed conditions in high-power engines. Simultaneously, the non-contact structure between the oil seal structure 3 and the oil slinger 4 reduces frictional losses and extends the service life of the crankshaft 5 oil seal device.

[0029] In some embodiments, please refer to Figure 5 and Figure 6 , Figure 5 This is a schematic diagram of the structure of the oil slinger 4 provided in an exemplary embodiment of this application; Figure 6This is a schematic diagram of the structure of the oil slinger 4 provided in another exemplary embodiment of this application. When the medium in the first chamber 8 is pure air, the pumping pressure in the first chamber 8 is set to 0.25 to 0.5 times the pressure in the crankcase 1 by setting the structural parameters of the spiral structure 7. The flow state of the medium in the spiral structure 7 is evaluated through simulation calculation. During the calculation, the pressure of the crankcase 1 is set according to the actual situation. Since the pressure of the crankcase 1 fluctuates, in order to prevent outside air from entering the crankcase 1, the pressure in the spiral structure 7 is set to 1 / 4 to 1 / 2 of the pressure of the crankcase 1 when the medium in the first chamber 8 is pure air. It can be understood that when the pressure in the crankcase 1 is small and the first chamber 8 is mainly pure air, the pumping pressure generated by the spiral structure 7 is also relatively small due to the low air density. At this time, the pressure is designed to be 0.25 to 0.5 times the pressure in the crankcase 1. When the crankcase 1 contains an oil-air mixture and the outside is pure air, the spiral structure 7 is in a dynamic equilibrium state, achieving complete sealing. It is understandable that when the concentration of the oil-gas mixture in the crankcase 1 increases and the density of the medium entering the first chamber 8 increases, according to the principles of fluid mechanics, the pumping capacity of the spiral structure 7 will be adaptively enhanced, causing the pumping pressure to rise and eventually reach the same level as the pressure in the crankcase 1, thus achieving dynamic equilibrium.

[0030] In some embodiments, the structural parameters of the spiral structure 7 include the tooth height, groove width, tooth width, helix angle, and helix angle direction of the spiral groove. It forms a closed spiral cavity with the oil seal. During operation, the oil slinger 4 rotates at high speed with the crankshaft 5, generating pumping flow. The theoretical formula for the pumping flow rate is: ; Where v is the linear velocity of the helical shaft rotation in m / s, D is the outer diameter of the helical shaft in m, h is the thread height in m, K1 is the relative groove width, K1=a / (a+b), where a is the thread groove width, b is the thread tooth width, and α is the helix angle in °.

[0031] It is understandable that pumping flow rate and pressure are positively correlated. The pumping action creates air pressure at the helical structure in the direction from the outside to the crankcase 1, which balances the positive pressure formed by the pressure in the crankcase 1. The pumping flow rate of different media is basically the same. The pressure formed by the helical structure 7 is positively correlated with the density of the medium in the first chamber 8. When the medium in the first chamber 8 is pure air, the pressure formed is relatively small, so no large amount of outside air enters the crankcase 1. When some of the lubricating oil or oil-air mixture in the pressure stabilizing chamber 6 moves to the helical structure 7, a larger pressure is formed at the helical structure 7. The oil-air mixture cannot continue to move to the outside, and the pure air from the outside cannot enter the crankcase 1 due to the smaller pressure formed. Finally, an equilibrium state is formed at the helical structure 7, that is, no lubricating oil leaks out of the crankcase 1, thereby achieving a seal at the output end of the crankcase 1.

[0032] In some embodiments, please refer to Figure 3 , Figure 3 yes Figure 2 A partial structural diagram is shown; a second chamber 9 is located between the oil slinger 4 and the oil seal structure 3. The second chamber 9 is located on the side of the spiral structure 7 closer to the body 2 and is connected to the first chamber 8 and the pressure stabilizing chamber 6, respectively. Specifically, by introducing a labyrinth structure into the pressure stabilizing chamber 6 and the first chamber 8 to form the second chamber 9, the medium flow rate can be reduced. Under the action of centrifugal force and eddy current, the fine oil droplets in the oil-gas mixture are more easily separated from the airflow and adhere to the wall of the oil seal structure 3 or settle in the second chamber 9, providing a basis for subsequent oil return treatment.

[0033] In some embodiments, please refer to Figure 5 The oil slinger 4 includes multiple first sealing teeth 40, with a second chamber 9 between adjacent first sealing teeth 40. It is understood that the multiple first sealing teeth 40 are spaced apart axially on the crankshaft 5, and the multiple second chambers 9 are interconnected. When the oil-gas mixture in the crankcase 1 leaks out, it passes through the tortuous path formed by the pressure stabilizing chamber 6 and the first sealing teeth 40. During this process, the airflow expands and contracts due to the rapid change in cross-sectional area when passing through the first sealing teeth 40, forming small vortices between adjacent first sealing teeth 40. These vortices can dissipate the kinetic energy of the oil-gas mixture, significantly reducing its flow velocity.

[0034] In some embodiments, please refer to Figure 4 , Figure 4 This is a partial structural schematic diagram of the oil seal structure 3 provided in an exemplary embodiment of this application; the oil seal structure 3 includes a plurality of second sealing teeth 30, and a second chamber 9 is provided between the plurality of second sealing teeth 30. It is understood that the plurality of second sealing teeth 30 are spaced apart axially on the crankshaft 5, and the plurality of second chambers 9 are interconnected. When the oil-gas mixture in the crankcase 1 leaks out, it passes through the pressure stabilizing chamber 6 and the tortuous path formed by the second sealing teeth 30. During this process, the airflow expands and contracts due to the rapid change in cross-sectional area when passing through the second sealing teeth 30, forming small vortices between adjacent second sealing teeth 30. The vortices can consume the kinetic energy of the oil-gas mixture, significantly reducing its flow velocity.

[0035] In some embodiments, please refer to Figure 3 The oil slinger 4 includes multiple first sealing teeth 40, and the oil seal structure 3 includes multiple second sealing teeth 30. The multiple first sealing teeth 40 and the multiple second sealing teeth 30 are respectively arranged opposite to each other in the radial direction of the crankshaft 5, so that a narrow gap can be formed between the oppositely arranged first sealing teeth 40 and second sealing teeth 30, so that the pressure of the oil-gas mixture gradually decreases after passing through the multiple first sealing teeth 40 and second sealing teeth 30, and finally reduces the leakage force of the medium before reaching the end spiral structure 7.

[0036] In other embodiments, a plurality of first sealing teeth 40 are arranged alternately with a plurality of second sealing teeth 30 in the radial direction of the crankshaft 5.

[0037] In some embodiments, please refer to Figure 4 The oil seal structure 3 has an oil return channel 31, which communicates with the second chamber 9. The oil return channel 31 is used to guide the medium in the second chamber 9 to the oil pan. The oil seal structure 3 has an internal oil return channel 31, which is directly connected to the second chamber 9 and is used to receive the lubricating oil that is trapped by the sealed tooth structure and flows down the wall. The lubricating oil separated by the oil return channel 31 can be recovered in time, which can prevent the medium from accumulating in the labyrinth structure or spiral structure 7.

[0038] In some embodiments, please refer to Figure 4 The oil return channel 31 adopts a U-shaped design. Specifically, the oil return channel 31 includes a first channel 311, a second channel 312, and a third channel 313 connected in sequence. The first channel 311 and the third channel 313 are arranged opposite to each other, and the side of the first channel 311 away from the second channel 312 is connected to the second chamber 9. In this embodiment, the liquid seal effect formed by the U-shaped bend is used to isolate the second chamber 9 from the external environment and prevent pressure fluctuations from affecting the stability of the dynamic balance.

[0039] In some embodiments, please refer to Figure 4 The oil return channel 31 has an oil return port 310, which is used to communicate with the oil pan. The oil return port 310 is connected to the engine oil pan through a flow channel inside the engine block 2. With this configuration, the liquid lubricating oil can smoothly flow back to the oil pan by gravity and pressure difference, and be circulated through the lubrication system, effectively solving the problem of medium accumulation and leakage in the crankshaft 5 sealing device.

[0040] In some embodiments, please refer to Figure 5 and Figure 6 An oil baffle 41 is located on the side of the oil slinger 4 near the engine block 2. The oil baffle 41 and the oil seal structure 3 enclose a pressure stabilizing chamber 6. During engine operation, the lubricating oil splashed inside the crankcase 1 first contacts the rotating oil baffle 41, which uses centrifugal force to throw the lubricating oil towards the inner wall of the engine block 2. The pressure stabilizing chamber 6 provides a pressure buffer zone for the airflow entering the sealing gap, allowing the airflow pressure to stabilize before entering the subsequent second chamber 9. This avoids the lubricating oil directly impacting the spiral structure 7, further enhancing the sealing reliability of the crankshaft 5 oil seal device under high-power engine high oil supply conditions.

[0041] In some embodiments, please refer to Figure 1The oil seal structure 3 includes a first oil seal portion 32 and a second oil seal portion 33, which are respectively fixedly connected to the body 2 by fasteners 10. The oil seal structure 3 adopts a two-part split design for the first oil seal portion 32 and the second oil seal portion 33, which are connected to the body 2 by fasteners 10, such as high-strength bolts. This split structure improves the efficiency of installation and subsequent maintenance.

[0042] According to a second aspect of this application, a sealing control method for a crankshaft 5 oil seal device is provided, applied to the aforementioned crankshaft 5 oil seal device, the method comprising the following steps: The crankshaft 5 drives the oil slinger 4 to rotate. The spiral structure 7 generates pumping pressure in the first chamber 8 and keeps the pumping pressure in the first chamber 8 in dynamic balance with the pressure in the crankcase 1 to prevent the medium in the crankcase 1 from leaking outward.

[0043] With this configuration, the pumping pressure adaptive adjustment mechanism formed by the spiral structure 7 is utilized to achieve dynamic sealing of the medium inside the crankcase 1.

[0044] According to a third aspect of this application, an engine is also provided, comprising: The crankcase 1 includes an engine block 2 and the aforementioned crankshaft 5 oil seal device, which is connected to the engine block 2. Since the engine includes the aforementioned crankshaft 5 oil seal device, it possesses all the beneficial effects of the aforementioned crankshaft 5 oil seal device, which will not be elaborated further in this application.

[0045] This application exemplarily describes the working process of the minimal protected subject: During engine operation, lubricating oil in the crankcase 1 splashes onto the oil baffle 41 on the oil slinger 4. The oil slinger 4 rotates at high speed, throwing the lubricating oil towards the inner wall of the engine block 2, preventing the lubricating oil from directly splashing into the labyrinth structure. The oil seal structure 3 and the oil slinger 4 form a pressure stabilizing chamber 6 at the inlet of the second chamber 9. Lubricating oil entering through the gap can flow back to the oil pan from the bottom of the oil seal structure 3 through the wall of the pressure stabilizing chamber 6. The labyrinth structure set between the oil seal structure 3 and the oil slinger 4 includes multiple second chambers 9. Some oil mist enters the second chamber 9 through the gap between the oil seal structure 3 and the oil slinger 4. The second chamber 9 is equipped with a sealing tooth structure to slow down the flow rate of the oil mist and generate vortices, causing oil droplets to adhere to the wall of the oil seal structure 3. Most of the filtered lubricating oil droplets flow back to the oil pan through the return oil channel 31 on the oil slinger 4 and the return oil hole. Subsequently, some oil mist enters the spiral structure 7. As the medium inside the spiral structure 7 changes, the pressure generated by the spiral structure 7 increases. If the oil mist fills the spiral structure 7, the pressure formed is much greater than the pressure of the crankcase 1. Therefore, when the oil mist just begins to enter the spiral structure 7, the pressure formed can balance the pressure of the crankcase 1, so that the remaining oil mist cannot pass through the spiral structure 7, thereby achieving a seal.

[0046] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0047] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0048] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0049] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A crankshaft oil seal device, characterized in that, Located inside the crankcase and connected to the engine block within the crankcase, the crankshaft oil seal device is used to prevent leakage of the medium inside the crankcase. The device includes: Oil seal structure; An oil slinger is sleeved on the crankshaft, and a pressure stabilizing chamber is provided between the oil slinger and the oil seal structure; a spiral structure is provided on the side of the oil slinger away from the engine body, and a first chamber is provided between the spiral structure and the oil seal structure, and the first chamber is connected to the pressure stabilizing chamber; When the crankshaft drives the oil slinger to rotate, the pumping pressure in the first chamber and the pressure in the crankcase are in dynamic equilibrium.

2. The crankshaft oil seal device according to claim 1, characterized in that, When the medium in the first chamber is pure air, the pumping pressure in the first chamber is 0.25 to 0.5 times the pressure in the crankcase by setting the structural parameters of the spiral structure.

3. The crankshaft oil seal device according to claim 2, characterized in that, The structural parameters of the spiral structure include the tooth height, groove width, tooth width, helix angle, and direction of the helix angle.

4. The crankshaft oil seal device according to claim 1, characterized in that, There is a second chamber between the oil slinger and the oil seal structure. The second chamber is located on the side of the spiral structure closer to the body and is connected to the first chamber and the pressure stabilizing chamber, respectively.

5. The crankshaft oil seal device according to claim 4, characterized in that, The oil-slinger includes a plurality of first sealing teeth, with a second chamber between two adjacent first sealing teeth; and / or, The oil seal structure includes a plurality of second sealing teeth, and the second chamber is located between the plurality of second sealing teeth.

6. The crankshaft oil seal device according to claim 4, characterized in that, The oil slinger includes a plurality of first sealing teeth, and the oil seal structure includes a plurality of second sealing teeth, with the plurality of first sealing teeth and the plurality of second sealing teeth respectively arranged opposite to each other in the radial direction of the crankshaft.

7. The crankshaft oil seal device according to claim 4, characterized in that, The oil seal structure has an oil return channel that communicates with the second chamber and is used to guide the medium in the second chamber into the oil pan.

8. The crankshaft oil seal device according to claim 7, characterized in that, The oil return channel has an oil return port, which is used to communicate with the oil pan.

9. The crankshaft oil seal device according to claim 1, characterized in that, An oil baffle is provided on the side of the oil slinger near the machine body, and the oil baffle and the oil seal structure enclose the pressure stabilizing cavity.

10. The crankshaft oil seal device according to claim 1, characterized in that, The oil seal structure includes a first oil seal part and a second oil seal part, which are respectively fixedly connected to the machine body by fasteners.

11. A sealing control method for a crankshaft oil seal device, characterized in that, The method, applied to the crankshaft oil seal device as described in any one of claims 1 to 10, comprises the following steps: The crankshaft drives the oil slinger to rotate; The spiral structure generates pumping pressure in the first chamber and keeps the pumping pressure in the first chamber in dynamic equilibrium with the pressure in the crankcase, thereby preventing the medium in the crankcase from leaking outward.

12. An engine, characterized in that, include: A crankcase, the crankcase comprising a housing and a crankshaft oil seal device as described in any one of claims 1 to 10, the crankshaft oil seal device being connected to the housing.

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