EGR valve with excellent sealing performance

Abstract

The EGR valve with the excellent sealing performance comprises a valve body, a motor assembly, a valve rod, a valve rod transmission assembly and a valve plate, a motor cavity and an air cavity are formed in the valve body, the motor assembly is installed on the motor cavity, one end of the valve rod is in linkage with the motor assembly through the valve rod transmission assembly, and a return spring is further arranged in the valve body. The other end of the valve rod is connected with the valve block, a valve seat is installed at the air inlet end, corresponding to the air cavity, of the valve body, and an exhaust pipe is installed at the air outlet end, corresponding to the air cavity, of the valve body. The sealing assembly is arranged between the corresponding motor cavity and the air cavity in the valve body and used for sealing the outer wall of the valve rod and the inner wall of the valve body, the sealing assembly comprises a first sealing ring and a first sealing scraping piece, and the first sealing scraping piece is tightly attached to the side, close to the valve plate, of the first sealing ring. The sealing doctor blade is additionally arranged on the sealing ring between the valve rod and the valve body to protect the sealing ring, so that the service life of the sealing ring is prolonged, and a good protection effect on the internal sealing performance of the motor is achieved.

Description

Technical Field

[0001] This invention relates to the field of exhaust gas recirculation system technology, and in particular to a low-pressure EGR valve with excellent sealing performance. Background Technology

[0002] Exhaust Gas Recirculation (EGR) is a technology that separates a portion of the exhaust gases from the combustion chamber of an internal combustion engine and reintroduces them into the intake system for re-combustion. It can increase the throttle opening within a certain range and reduce throttling losses within a certain load range, thereby improving engine combustion efficiency and reducing fuel consumption. A commonly used low-pressure EGR valve works by energizing an output gear, which in turn drives a secondary gear meshing with the output gear to rotate counterclockwise. Inside the secondary gear is a crescent-shaped cam that pushes a valve stem linkage assembly downwards (the linkage assembly contains a magnet and a return spring). This linkage assembly pushes the valve stem and valve plate assembly vertically downwards along the axis. A sealing ring on the valve stem prevents corrosion inside the motor. As the valve stem displacement increases, the opening between the valve plate and the valve body intake increases until the valve stem reaches its maximum stroke, at which point the opening is at its maximum. When the power supply ends, the return spring provides a reaction force, pulling the valve stem vertically upwards back to its initial position. During the axial movement of the valve stem, exhaust gases and deposits corrode and damage the sealing rings, leading to a decrease in the sealing performance of the EGR valve. Exhaust gases and impurities can also be carried along the valve stem into the motor assembly, where further chemical reactions occur, generating new substances that corrode the internal motor structure, causing the motor to seize and fail, thus affecting the product's service life. Summary of the Invention

[0003] The purpose of this invention is to provide an EGR valve with excellent sealing performance. This invention protects the sealing ring by adding a sealing scraper to the sealing ring between the valve stem and the valve body, thereby extending the service life of the sealing ring and providing good protection for the internal sealing of the motor assembly.

[0004] To achieve the above objectives, the present invention provides the following technical solution: an EGR valve with excellent sealing performance, comprising a valve body, a motor assembly, a valve stem, a valve stem transmission assembly, and a valve plate. The valve body has a motor cavity and an air cavity. The motor assembly is mounted on the motor cavity. The valve stem passes through the motor cavity and the air cavity, and one end of the valve stem located in the motor cavity is linked to the motor assembly through the valve stem transmission assembly. The valve body also has a return spring that acts on the valve stem to cause it to reset. One end of the valve stem located in the air cavity is connected to the valve plate. A valve seat is installed on the valve body at the air inlet end corresponding to the air cavity to form a seal when it cooperates with the valve plate. An exhaust pipe is installed on the valve body at the air outlet end corresponding to the air cavity. The air cavity has an inverted L-shaped passage. The EGR valve also includes a sealing assembly disposed between the motor cavity and the air cavity in the valve body to form a seal between the outer wall of the valve stem and the inner wall of the valve body. The sealing assembly includes a first sealing ring and a first sealing scraper. The first sealing scraper is tightly disposed on the side of the first sealing ring near the valve plate.

[0005] By adopting the above technical solution, the sealing assembly uses a combination structure of a first sealing ring and a first sealing scraper. The first sealing ring provides basic sealing between the valve body and the valve stem, while the first sealing scraper protects the first sealing ring. During valve stem displacement, due to the tight fit between the first sealing scraper and the valve stem, the scraper can remove exhaust gas and deposits from the surface of the valve stem as it moves upwards, protecting the first sealing ring from corrosion by deposits and exhaust gas. This greatly increases the sealing performance of the EGR valve, solves the problem of difficult sealing ring replacement, and reduces the frequency of replacement. Without the first sealing scraper, the first sealing ring is easily damaged after operation, reducing the sealing performance of the EGR valve. Deposits trapped inside the first sealing ring can damage the smooth surface of the valve stem and accelerate corrosion, reducing its service life. Therefore, this structure effectively prevents the occurrence of these adverse phenomena.

[0006] The present invention is further configured such that the sealing assembly further includes a second sealing ring and a second sealing scraper, wherein the first sealing ring, the first sealing scraper, the second sealing ring, and the second sealing scraper are arranged sequentially in the direction close to the valve plate.

[0007] By adopting the above technical solution, and using double sealing rings and double sealing scrapers for secondary protection, the sealing performance of the sealing assembly is further improved. At the same time, the design of the sealing ring on top and the sealing scraper on the bottom can effectively prevent the motor from jamming, thereby preventing the EGR valve from failing.

[0008] The present invention is further configured such that both the first sealing scraper and the second sealing scraper are annular corrosion-resistant metal components.

[0009] By adopting the above technical solutions, its service life can be extended and the number of replacements can be reduced.

[0010] The present invention is further configured such that a sealing spacer is sandwiched between the second sealing ring and the first sealing scraper, the sealing spacer having a structure that is thick in the middle and gradually narrows at both ends, and a reinforcing flange is provided circumferentially at the middle of the outer circle of the sealing spacer.

[0011] By adopting the above technical solution, the structure has high strength and is not easily deformed. It not only has a long service life, but also ensures the stability of the installation of the two sets of sealing rings and sealing scrapers.

[0012] The present invention is further configured such that the sealing assembly includes a first inner liner and a second inner liner fitted around the outer periphery of the valve stem, wherein the outer circumference of the first inner liner and the outer circumference of the second inner liner are respectively provided with a first annular positioning recess and a second annular positioning recess, and the first sealing ring and the second sealing ring are respectively embedded in the first annular positioning recess and the second annular positioning recess.

[0013] By adopting the above technical solution, the first inner liner and the second inner liner can respectively position and support the first sealing ring and the second sealing ring, which can not only improve the stability of the installation of the first sealing ring and the second sealing ring, but also further improve the service life of the first sealing ring and the second sealing ring.

[0014] The invention is further configured to include a guide copper sleeve and a front guide sleeve that are sequentially sleeved around the outer periphery of the valve stem from top to bottom. The front guide sleeve is connected to the inner wall of the valve body and abuts against the lower end of the guide copper sleeve, so that the guide copper sleeve presses the sealing assembly against the inner wall of the valve body and seals the gap between the valve stem and the valve body.

[0015] By adopting the above technical solution, it can be ensured that the valve stem does not deviate when it moves axially, thus improving the reliability of the EGR valve.

[0016] The invention is further configured such that the valve stem transmission assembly includes a linkage, the linkage being threadedly connected to the upper end of the valve stem, and a bearing is mounted on the linkage via a bearing pin; the motor assembly includes a drive motor, an output gear, and a cam gear, the drive motor being mounted on the valve body, and the motor shaft of the drive motor being linked to the output gear, the cam gear being rotatably mounted on the valve body via a positioning pin, the cam gear meshing with the output gear, and the outer circular surface of the bearing engaging with the outer peripheral surface of the cam on the cam gear.

[0017] By adopting the above technical solution, the transmission structure from the drive motor to the valve stem is simple and reliable, and has the advantages of low friction, low noise, and low energy consumption.

[0018] The present invention is further configured such that a displacement sensor is installed on the linkage.

[0019] By adopting the above technical solution, in order to prevent the valve stem from jamming due to the increase of the sealing ring, a displacement sensor is installed on the linkage. Under the action of the return spring, it is possible to read whether the valve stem has returned to the initial position.

[0020] The present invention is further configured such that the valve plate has a bowl-shaped structure with the opening facing downwards, the valve plate is fitted around the outer periphery of the valve stem, and the valve plate is fixed to the lower end of the valve stem by laser welding.

[0021] By adopting the above technical solution, not only is the processing convenient, but the special structure of the valve plate also makes its sealing performance better when it is matched with the valve seat.

[0022] The present invention is further configured such that the valve body is provided with a motor connection plug, one end of the motor connection plug is electrically connected to an external power source via a cable, and the other end of the motor connection plug is electrically connected to the input end of the drive motor via a wire.

[0023] By adopting the above technical solution, it is easy to connect the drive motor to the external power supply, which is beneficial for the initial assembly and subsequent maintenance operations. Attached Figure Description

[0024] Figure 1 This is a front view of the entire invention; Figure 2 This is a side view of the entire invention; Figure 3 This is a partial structural diagram of the present invention; Figure 4 for Figure 3 Enlarged structural diagram of section A in the middle; Figure 5 This is a schematic diagram of the internal structure of the present invention; Figure 6 This is a schematic diagram of the mating structure of the first sealing ring, the first sealing scraper, and the first inner liner of the present invention; Figure 7 This is a schematic diagram of the structure of the first inner liner of the present invention.

[0025] In the diagram: 1. Valve body; 2. Motor assembly; 3. Valve stem; 4. Valve stem transmission assembly; 5. Valve plate; 6. Motor cavity; 7. Air cavity; 8. Return spring; 9. Valve seat; 10. Exhaust pipe; 11. Sealing assembly; 12. First sealing ring; 13. First sealing scraper; 14. Second sealing ring; 15. Second sealing scraper; 16. Sealing spacer; 17. Reinforcing flange; 18. First inner liner; 19. Second inner liner; 20. First annular positioning recess; 21. Second annular positioning recess; 22. Guide copper sleeve; 23. Front guide sleeve; 24. Linkage component; 25. Bearing pin; 26. Bearing; 27. Drive motor; 28. Output gear; 29. ​​Cam gear; 30. Positioning pin; 31. Displacement sensor; 32. Motor connecting plug. Detailed Implementation

[0026] 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.

[0027] Example: As attached Figures 1-7The EGR valve shown includes a valve body 1, a motor assembly 2, a valve stem 3, a valve stem transmission assembly 4, and a valve plate 5. The valve body 1 contains a motor cavity 6 and a gas cavity 7. The motor assembly 2 is mounted on the motor cavity 6 and provides power output to the EGR valve. The valve stem 3 passes through both the motor cavity 6 and the gas cavity 7, and one end of the valve stem 3 located in the motor cavity 6 is linked to the motor assembly 2 via the valve stem transmission assembly 4. The valve body 1 also contains a return spring 8 that acts on the valve stem 3 to reset it. One end of the valve stem 3 located in the gas cavity 7 is connected to the valve plate 5. The valve body 1 has a corresponding gas... The air inlet end of the chamber 7 is equipped with a valve seat 9 for forming a seal when it cooperates with the valve plate 5. The valve stem 3 drives the valve plate 5 to move axially to control the opening size of the valve plate 5 and the valve seat 9. An exhaust pipe 10 is installed on the valve body 1 corresponding to the air outlet end of the air chamber 7. It also includes a sealing assembly 11 disposed in the valve body 1 between the motor chamber 6 and the air chamber 7 for forming a seal between the outer wall of the valve stem 3 and the inner wall of the valve body 1. The sealing assembly 11 includes a first sealing ring 12 and a first sealing scraper 13. The first sealing ring 12 and the first sealing scraper 13 are tightly fitted with the valve stem 3. The first sealing scraper 13 is closely disposed on the side of the first sealing ring 12 near the valve plate 5. The sealing assembly 11 adopts a combination structure of a first sealing ring 12 and a first sealing scraper 13. The first sealing ring 12 provides basic sealing between the valve body 1 and the valve stem 3. The first sealing scraper 13 protects the first sealing ring 12. During the displacement of the valve stem 3, due to the tight fit between the first sealing scraper 13 and the valve stem 3, the first sealing scraper 13 can scrape off the exhaust gas and deposits on the surface of the valve stem 3 as it moves upward, protecting the first sealing ring 12 from corrosion by deposits and exhaust gas. This greatly increases the sealing performance of the EGR valve, solves the problem of difficult sealing ring replacement, and reduces the frequency of sealing ring replacement. At the same time, by effectively preventing the generation of contaminants, the inside of the motor assembly 2 can be kept clean and tidy, reducing the probability of the drive motor 27 jamming and failure, as well as the phenomenon of gear meshing sticking, effectively ensuring the normal operation of the motor assembly 2. If the first sealing scraper 13 is not installed, the first sealing ring 12 is easily damaged after operation, reducing the sealing performance of the EGR valve. Deposits stuck in the first sealing ring 12 will damage the smooth surface of the valve stem 3 and accelerate the corrosion of the valve stem 3, reducing its service life. Therefore, this structure can effectively prevent the occurrence of the aforementioned adverse phenomena.

[0028] As attached Figure 4As shown, the sealing assembly 11 also includes a second sealing ring 14 and a second sealing scraper 15. The second sealing ring 14 and the second sealing scraper 15 are tightly fitted with the valve stem 3. The first sealing ring 12, the first sealing scraper 13, the second sealing ring 14, and the second sealing scraper 15 are arranged sequentially in the direction close to the valve plate 5, that is, the positions and directions of the two sets of sealing rings and sealing scrapers are consistent. The use of double sealing rings and double sealing scrapers for secondary protection further improves the sealing performance of the sealing assembly 11. At the same time, the design of the sealing ring on top and the sealing scraper on the bottom can effectively prevent the motor from jamming, thereby preventing the EGR valve from failing.

[0029] Both the first sealing scraper 13 and the second sealing scraper 15 are annular corrosion-resistant metal components. This structure extends their service life and reduces the frequency of replacement.

[0030] As attached Figure 4 As shown, a sealing spacer 16 is sandwiched between the second sealing ring 14 and the first sealing scraper 13. The sealing spacer 16 has a structure that is thicker in the middle and gradually narrows at both ends, and a reinforcing flange 17 is provided circumferentially at the center of the outer circle of the sealing spacer 16. The sealing spacer 16 is located between the two sealing rings and the sealing scraper, ensuring a certain distance between the two sealing rings. This design structure has high strength, is not easily deformed, has a long service life, and can ensure the stability of the installation of the two sets of sealing rings and sealing scrapers.

[0031] As attached Figure 4 , 6 As shown in Figure 7, the sealing assembly 11 further includes a first inner liner 18 and a second inner liner 19 fitted around the outer periphery of the valve stem 3. The outer circumferences of the first inner liner 18 and the second inner liner 19 are respectively provided with a first annular positioning recess 20 and a second annular positioning recess 21. The first sealing ring 12 and the second sealing ring 14 are respectively embedded in the first annular positioning recess 20 and the second annular positioning recess 21. The first inner liner 18 and the second inner liner 19 can respectively position and support the first sealing ring 12 and the second sealing ring 14, which not only improves the stability of the installation of the first sealing ring 12 and the second sealing ring 14, but also further extends the service life of the first sealing ring 12 and the second sealing ring 14.

[0032] As attached Figure 3As shown, the EGR valve also includes a guide copper sleeve 22 and a front guide sleeve 23, which are sequentially fitted around the outer periphery of the valve stem 3 from top to bottom. The front guide sleeve 23 is connected to the inner wall of the valve body 1 (by screws). The front guide sleeve 23 abuts against the lower end of the guide copper sleeve 22, so that the guide copper sleeve 22 presses the sealing assembly 11 against the inner wall of the valve body 1, sealing the gap between the valve stem 3 and the valve body 1. A coaxial sealing groove can be provided on the inner wall of the valve body 1, and the sealing assembly 11 is embedded in the sealing groove. When the sealing assembly 11 is subjected to axial pressure, the sealing ring inside the sealing assembly 11 undergoes radial deformation, achieving a seal between the valve stem 3 and the valve body 1. This design can ensure that the valve stem 3 is coaxially constrained when it moves axially, preventing it from shifting and improving the reliability of the EGR valve.

[0033] As attached Figure 3 and attached Figure 5 As shown, the valve stem transmission assembly 4 includes a linkage 24, which is threaded to the upper end of the valve stem 3. A bearing 26 is mounted on the linkage 24 via a bearing pin 25. The motor assembly 2 includes a drive motor 27, an output gear 28, and a cam gear 29. The drive motor 27 is mounted on the valve body 1, and the motor shaft of the drive motor 27 is linked to the output gear 28. The cam gear 29 is rotatably mounted on the valve body 1 via a positioning pin 30. The cam gear 29 meshes with the output gear 28. The output gear 28 is a pinion, and the cam gear 29 is a gear. The outer surface of the bearing 26 engages with the outer circumferential surface of the cam on the cam gear 29. The cam is crescent-shaped. Under a certain duty cycle, the cam gear 29 drives the cam to rotate for a certain period of time, performing reciprocating motion. The valve stem 3 transmission rod assembly converts the rotational force of the gear into axial force, causing the valve stem 3 to move downwards. Simultaneously, it compresses the return spring 8. During one cycle of the drive motor 27, the valve stem transmission assembly 4 moves to its lowest point, at which point the stroke is at its maximum. When the drive motor 27 is not operating, the return spring 8 releases energy, causing the valve stem 3 to return to its initial position. The transmission structure from the drive motor 27 to the valve stem 3 is simple and reliable, with advantages such as low friction, low noise, and low energy consumption.

[0034] As attached Figure 5 As shown, a displacement sensor 31 is installed on the linkage 24. To prevent the valve stem 3 from getting stuck due to the increase in the sealing ring, the displacement sensor 31 is installed on the linkage 24. Under the action of the return spring 8, it can read whether the valve stem 3 has returned to the initial position.

[0035] The valve plate 5 has a bowl-shaped structure with its opening facing downwards. The valve plate 5 is fitted around the outer periphery of the valve stem 3 and is fixed to the lower end of the valve stem 3 by laser welding. This design not only facilitates processing and extends service life, but the special structure of the valve plate 5 also ensures better sealing performance when it mates with the valve seat 9.

[0036] As attached Figure 1 Or attached Figure 2 As shown, the valve body 1 is equipped with a motor connection plug 32, i.e., a motor connector. One end of the motor connection plug 32 is electrically connected to an external power source via a cable, and the other end of the motor connection plug 32 is electrically connected to the input terminal of the drive motor 27 via a wire. This design facilitates the electrical connection of the drive motor 27 to an external power source, which is beneficial for initial assembly and subsequent maintenance operations.

Claims

1. An EGR valve with excellent sealing performance, comprising a valve body (1), a motor assembly (2), a valve stem (3), a valve stem transmission assembly (4), and a valve plate (5), wherein the valve body (1) is provided with a motor cavity (6) and an air cavity (7), the motor assembly (2) is mounted on the motor cavity (6), the valve stem (3) is disposed through the motor cavity (6) and the air cavity (7), and one end of the valve stem (3) located in the motor cavity (6) is connected to the valve plate through the valve stem transmission assembly (4). The motor assembly (2) forms a linkage, and the valve body (1) is also provided with a return spring (8) that acts on the valve stem (3) to cause the valve stem (3) to reset. One end of the valve stem (3) located in the air chamber (7) is connected to the valve plate (5). A valve seat (9) is installed on the valve body (1) at the air inlet end corresponding to the air chamber (7) to form a seal when it cooperates with the valve plate (5). An exhaust pipe (10) is installed on the valve body (1) at the air outlet end corresponding to the air chamber (7). The feature is that: It also includes a sealing assembly (11) disposed in the valve body (1) between the motor cavity (6) and the air cavity (7) for sealing the outer wall of the valve stem (3) and the inner wall of the valve body (1). The sealing assembly (11) includes a first sealing ring (12) and a first sealing scraper (13). The first sealing scraper (13) is disposed close to the first sealing ring (12) on the side near the valve plate (5).

2. The EGR valve with excellent sealing performance according to claim 1, characterized in that: The sealing assembly (11) further includes a second sealing ring (14) and a second sealing scraper (15), wherein the first sealing ring (12), the first sealing scraper (13), the second sealing ring (14) and the second sealing scraper (15) are arranged sequentially in the direction close to the valve plate (5).

3. The EGR valve with excellent sealing performance according to claim 2, characterized in that: Both the first sealing scraper (13) and the second sealing scraper (15) are annular corrosion-resistant metal components.

4. The EGR valve with excellent sealing performance according to claim 2, characterized in that: A sealing spacer (16) is sandwiched between the second sealing ring (14) and the first sealing scraper (13). The sealing spacer (16) has a structure that is thick in the middle and gradually narrows at both ends, and a reinforcing flange (17) is provided in the circumferential direction at the middle of the outer circle of the sealing spacer (16).

5. The EGR valve with excellent sealing performance according to claim 4, characterized in that: The sealing assembly (11) further includes a first inner liner (18) and a second inner liner (19) fitted around the outer periphery of the valve stem (3). The outer circle of the first inner liner (18) and the outer circle of the second inner liner (19) are respectively provided with a first annular positioning recess (20) and a second annular positioning recess (21). The first sealing ring (12) and the second sealing ring (14) are respectively embedded in the first annular positioning recess (20) and the second annular positioning recess (21).

6. An EGR valve with excellent sealing performance according to claim 2 or 5, characterized in that: It also includes a guide copper sleeve (22) and a front guide sleeve (23) that are sequentially sleeved around the outer periphery of the valve stem (3) from top to bottom. The front guide sleeve (23) is connected to the inner wall of the valve body (1). The front guide sleeve (23) abuts against the lower end of the guide copper sleeve (22), so that the guide copper sleeve (22) presses the sealing assembly (11) against the inner wall of the valve body (1) and seals the gap between the valve stem (3) and the valve body (1).

7. The EGR valve with excellent sealing performance according to claim 1, characterized in that: The valve stem transmission assembly (4) includes a linkage (24), which is threaded to the upper end of the valve stem (3). A bearing (26) is mounted on the linkage (24) via a bearing pin (25). The motor assembly (2) includes a drive motor (27), an output gear (28), and a cam gear (29). The drive motor (27) is mounted on the valve body (1), and the motor shaft of the drive motor (27) is linked to the output gear (28). The cam gear (29) is rotatably mounted on the valve body (1) via a positioning pin (30). The cam gear (29) meshes with the output gear (28), and the outer surface of the bearing (26) engages with the outer circumferential surface of the cam on the cam gear (29).

8. The EGR valve with excellent sealing performance according to claim 7, characterized in that: A displacement sensor (31) is installed on the linkage (24).

9. The EGR valve with excellent sealing performance according to claim 1, characterized in that: The valve plate (5) has a bowl-shaped structure with the opening facing downwards. The valve plate (5) is fitted around the outer periphery of the valve stem (3) and is fixed to the lower end of the valve stem (3) by laser welding.

10. An EGR valve with excellent sealing performance according to claim 1, characterized in that: The valve body (1) is provided with a motor connection plug (32). One end of the motor connection plug (32) is electrically connected to an external power source via a cable, and the other end of the motor connection plug (32) is electrically connected to the input end of the drive motor (27) via a wire.

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