EGR valve, engine assembly and vehicle

Abstract

The EGR valve comprises a shell, a driving device, a valve shaft, a valve plate and a lining, the shell is provided with a through hole, the lining is assembled in the through hole, an inner hole of the lining forms a gas flow channel, and the driving device is arranged in the gas flow channel. The valve shaft is rotationally connected to the shell and penetrates through the lining and the gas flow channel in the radial direction of the lining, and the valve plate is installed on the valve shaft and located in the gas flow channel. The lining is used for preventing condensed water generated by gas flowing through the gas flow channel from directly contacting with the shell; the driving device is used for driving the valve shaft to rotate so as to drive the valve plate to rotate around the axis of the valve shaft, and then the gas flow area of the gas flow channel is adjusted. According to the EGR valve provided by the utility model, the corrosion of condensate water to the shell of the EGR valve can be reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of exhaust gas recirculation, and relates to an EGR valve, an engine assembly and a vehicle. Background Art

[0002] EGR (Exhaust Gas Re-circulation) means that a part of the exhaust gas (EGR gas) discharged from the engine is sent back to the intake manifold and enters the cylinder again together with the fresh air-fuel mixture. The EGR valve is the core component of the EGR system and is used to regulate the flow rate of the EGR gas entering the intake manifold of the engine. When the temperature of the high-temperature EGR gas drops below the dew point temperature, condensed water will be separated from the EGR gas. If the production of condensed water is not controlled, it may cause the engine to stall or corrode the EGR valve seriously.

[0003] Currently, the common method on the market to reduce the generation of condensed water is to use the high-temperature cooling water of the engine itself to cool the EGR gas through the EGR cooler, so that the outlet temperature of the EGR cooler is controlled above 57°C (dew point temperature) to avoid the generation of condensed water and reduce the corrosion of the EGR valve by the condensed water.

[0004] However, with the development of hybrid vehicles, only the motor usually works at low speeds, and the engine works intermittently. It is difficult for the engine water temperature to be stably above 60°C for a long time, and it is also difficult to control the outlet temperature of the EGR cooler above the dew point temperature. Especially for the cooling scheme that uses a medium-temperature cooling system to cool the EGR gas, the outlet temperature of the EGR cooler is usually below the dew point temperature, and the generation of condensed water in the EGR valve housing is inevitable. The EGR valve housing is usually made of aluminum alloy, and its corrosion resistance is poor.

[0005] Therefore, it is necessary to reduce the corrosion of the EGR valve housing by condensed water. Summary of the Invention

[0006] The technical problem to be solved by the utility model is to provide an EGR valve, an engine assembly and a vehicle to reduce the corrosion of the EGR valve housing by condensed water.

[0007] To solve the above technical problem, on the one hand, the utility model provides an EGR valve, which includes a housing, a driving device, a valve shaft, a valve plate and a bushing. The housing is provided with a through hole, the bushing is assembled in the through hole, the inner hole of the bushing forms a gas flow channel, the valve shaft is rotatably connected to the housing and passes through the bushing and the gas flow channel along the radial direction of the bushing, and the valve plate is installed on the valve shaft and located in the gas flow channel; the bushing is used to prevent the condensed water generated by the gas flowing through the gas flow channel from directly contacting the housing;

[0008] The driving device is used to drive the valve shaft to rotate, so as to drive the valve plate to rotate around the axis of the valve shaft, and further adjust the gas flow area of the gas flow passage.

[0009] In the EGR valve provided by the embodiment of the present invention, the bushing is assembled in the through hole of the housing, and the inner hole of the bushing forms a gas flow passage for the EGR gas to pass through. In this way, when the EGR gas passes through the EGR valve, the EGR gas does not directly contact the housing, and the condensed water generated when the EGR gas flows through the EGR valve directly drips on the inner hole wall of the bushing. Therefore, the corrosion of the housing of the EGR valve by the condensed water can be reduced.

[0010] Optionally, the outer peripheral surface of the bushing is closely attached to the hole wall of the through hole.

[0011] Optionally, a first sealing surface and a second sealing surface are respectively formed at both axial ends of the through hole;

[0012] The bushing includes a bushing body, a first flange and a second flange. The first flange is connected to one axial end of the bushing body and protrudes radially outward from the bushing body along the axial direction of the bushing body. The second flange is connected to the other axial end of the bushing body and protrudes radially outward from the bushing body along the axial direction of the bushing body;

[0013] The first flange is in sealing fit with the first sealing surface, and the second flange is in sealing fit with the second sealing surface.

[0014] Optionally, a first convex ring protruding inward from the through hole is provided at one axial end of the through hole, and a second convex ring protruding inward from the through hole is provided at the other axial end of the through hole;

[0015] An annular first groove is formed at the joint of the first flange and the bushing body, and an annular second groove is formed at the joint of the second flange and the bushing body. The first convex ring is embedded in the first groove, and the second convex ring is embedded in the second groove.

[0016] Optionally, the two surface of the housing on both sides of the axial direction of the through hole are respectively a first surface and a second surface;

[0017] The first surface is spaced from the first convex ring to form the first sealing surface between the first convex ring and the first surface. The first sealing surface has a first radial part extending in the radial direction of the bushing and a first axial part extending in the axial direction of the bushing; the second surface is spaced from the second convex ring to form the second sealing surface between the second convex ring and the second surface. The second sealing surface has a second radial part extending in the radial direction of the bushing and a second axial part extending in the axial direction of the bushing;

[0018] The surface of the first flange close to the first convex ring along the axial direction of the bushing fits with the first radial part, and the outer peripheral surface of the first flange fits with the first axial part; the surface of the second flange close to the second convex ring along the axial direction of the bushing fits with the second radial part, and the outer peripheral surface of the second flange fits with the second axial part.

[0019] Optionally, the bushing is a stainless steel bushing.

[0020] Optionally, the bushing is integrally formed in the housing;

[0021] And / or,

[0022] The housing is made of aluminum alloy.

[0023] Optionally, the corrosion resistance of the bushing is not lower than that of stainless steel of model SUS316L;

[0024] And / or,

[0025] The valve shaft and the valve plate are made of stainless steel, and the corrosion resistance of the valve shaft and the valve plate is not lower than that of stainless steel of model SUS316L.

[0026] Optionally, it further includes a first bearing, a second bearing, a first sealing structure and a second sealing structure. First mounting holes and second mounting holes are provided on opposite sides of the housing along the radial direction of the bushing;

[0027] First through holes and second through holes penetrating along the radial direction of the bushing are provided on the outer peripheral wall of the bushing. The first through hole is connected between the gas flow channel and the first mounting hole, and the second through hole is connected between the gas flow channel and the second mounting hole;

[0028] The outer ring of the first bearing is press-fitted in the first mounting hole, one axial end of the valve shaft passes through the first through hole and is press-fitted in the inner ring of the first bearing, the outer ring of the second bearing is press-fitted in the second mounting hole, and the other axial end of the valve shaft passes through the second through hole and is press-fitted in the inner ring of the second bearing;

[0029] The first sealing structure is arranged between the inner ring of the first bearing and the outer peripheral surface of the valve shaft to seal the gap between the inner ring of the first bearing and the outer peripheral surface of the valve shaft; the second sealing structure is arranged between the inner ring of the second bearing and the outer peripheral surface of the valve shaft to seal the gap between the inner ring of the second bearing and the outer peripheral surface of the valve shaft.

[0030] Optionally, the first bearing is a needle bearing;

[0031] And / or,

[0032] The second bearing is a needle bearing.

[0033] Optionally, the first sealing structure includes a first sealing ring and a second sealing ring. A first sealing groove is provided at one end of the inner ring of the first bearing away from the second bearing, and a second sealing groove is provided at one end of the inner ring of the first bearing close to the second bearing. The first sealing ring is press-fitted in the first sealing groove, and the inner ring of the first sealing ring is in sealing contact with the outer peripheral surface of the valve shaft. The second sealing ring is press-fitted in the second sealing groove, and the inner ring of the second sealing ring is in sealing contact with the outer peripheral surface of the valve shaft. Along the axial direction of the first bearing, the rollers of the first bearing are located between the first sealing ring and the second sealing ring.

[0034] The second sealing structure includes a third sealing ring and a fourth sealing ring. A third sealing groove is provided at one end of the inner ring of the second bearing away from the first bearing, and a fourth sealing groove is provided at one end of the inner ring of the second bearing close to the first bearing. The third sealing ring is press-fitted in the third sealing groove, and the inner ring of the third sealing ring is in sealing contact with the outer peripheral surface of the valve shaft. The fourth sealing ring is press-fitted in the fourth sealing groove, and the inner ring of the fourth sealing ring is in sealing contact with the outer peripheral surface of the valve shaft. Along the axial direction of the second bearing, the rollers of the second bearing are located between the third sealing ring and the fourth sealing ring.

[0035] Optionally, there are two second sealing grooves and two second sealing rings, and each second sealing ring is press-fitted in the corresponding second sealing groove.

[0036] and / or

[0037] There are two fourth sealing grooves and two fourth sealing rings, and each fourth sealing ring is press-fitted in the corresponding fourth sealing groove.

[0038] Optionally, the outer ring and the inner ring of the first bearing are made of stainless steel, and the corrosion resistance of the outer ring and the inner ring of the first bearing is not lower than that of stainless steel of model SUS316L.

[0039] and / or

[0040] The outer ring and the inner ring of the first bearing are made of stainless steel, and the corrosion resistance of the outer ring and the inner ring of the second bearing is not lower than that of stainless steel of model SUS316L.

[0041] Optionally, the valve shaft is in clearance fit with the hole wall of the first through hole and in clearance fit with the hole wall of the second through hole.

[0042] Optionally, the first perforation includes a first large-diameter hole, a first small-diameter hole, and a first medium-diameter hole connecting between the first large-diameter hole and the first small-diameter hole. The first large-diameter hole, the first medium-diameter hole, and the first small-diameter hole are all circular holes and their diameters decrease in sequence. A first limiting surface is formed at the junction of the first large-diameter hole and the first medium-diameter hole. One end of the first bearing extends into the first large-diameter hole and abuts against the first limiting surface;

[0043] The second perforation includes a second large-diameter hole, a second small-diameter hole, and a second medium-diameter hole connecting between the second large-diameter hole and the second small-diameter hole. The second large-diameter hole, the second medium-diameter hole, and the second small-diameter hole are all circular holes and their diameters decrease in sequence. A second limiting surface is formed at the junction of the second large-diameter hole and the second medium-diameter hole. One end of the second bearing extends into the second large-diameter hole and abuts against the second limiting surface.

[0044] Optionally, the clearance between the hole wall of the first small-diameter hole and the valve shaft is smaller than the clearance between the first medium-diameter hole and the valve shaft;

[0045] The clearance between the hole wall of the second small-diameter hole and the valve shaft is smaller than the clearance between the second medium-diameter hole and the valve shaft.

[0046] Optionally, the second mounting hole includes an adjacent first hole section and a second hole section. The first hole section is connected between the second perforation and the second hole section. The second hole section penetrates through the housing. A plug is arranged in the second hole section for blocking the second mounting hole. The other axial end of the valve shaft is located inside the plug.

[0047] Optionally, a valve plate mounting groove is arranged on the part of the valve shaft located in the gas flow channel. The valve plate mounting groove penetrates through the valve shaft along the radial direction of the valve shaft. The valve plate is inserted into the valve plate mounting groove.

[0048] Optionally, the driving device includes a motor and a transmission mechanism. The motor and the transmission mechanism are mounted on the housing. The transmission mechanism is connected between one axial end of the valve shaft and the output shaft of the motor;

[0049] The motor is used to drive the valve shaft to rotate through the transmission mechanism.

[0050] Optionally, the housing includes a main housing and an outer cover. The outer cover is connected to the main housing to form a transmission mechanism mounting cavity therebetween. The transmission mechanism is accommodated in the transmission mechanism mounting cavity. The main housing includes an air passage part and a motor mounting part. The through hole is formed in the air passage part. The valve shaft is rotatably connected to the air passage part. The motor mounting part forms a motor mounting cavity. The motor is accommodated in the motor mounting cavity.

[0051] On the other hand, an embodiment of the present utility model provides an engine assembly, including an engine and the above-mentioned EGR valve, and the gas flow passage is connected between the exhaust pipe and the intake pipe of the engine.

[0052] On yet another aspect, an embodiment of the present utility model provides a vehicle, including the above-mentioned EGR valve or the above-mentioned engine assembly. Description of the Drawings

[0053] Figure 1 is a side view of the EGR valve provided by the first embodiment of the present utility model;

[0054] Figure 2 is a cross-sectional view taken along the A-A direction in;

[0055] Figure 3 is an internal structure diagram of the EGR valve provided by the first embodiment of the present utility model.

[0056] The reference numerals in the specification are as follows:

[0057] 1. Housing; 11. Through hole; 111. First sealing surface; 112. Second sealing surface; 113. First convex ring; 114. Second convex ring; 12. First surface; 13. Second surface; 14. First mounting hole; 15. Second mounting hole; 151. First hole section; 152. Second hole section; 16. Main housing; 161. Airway part; 162. Motor mounting part; 17. Outer cover; 2. Valve shaft; 3. Valve plate; 4. Bushing; 41. Gas flow passage; 42. Bushing main body; 43. First flange; 44. Second flange; 45. First perforation; 46. Second perforation; 5. Bolt; 6. First bearing; 7. Second bearing; 8. First sealing structure; 81. First sealing ring; 82. Second sealing ring; 9. Second sealing structure; 91. Third sealing ring; 92. Fourth sealing ring; 10. Plug; 20. Motor; 30. Transmission mechanism. Detailed Embodiments

[0058] In order to make the technical problems, technical solutions and beneficial effects solved by the present utility model clearer, the present utility model will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0059] See Figures 1 to 3, the EGR valve provided by an embodiment of the present utility model includes a housing 1, a driving device, a valve shaft 2, a valve plate 3 and a bushing 4. The housing 1 is provided with a through hole 11, the bushing 4 is assembled in the through hole 11, the inner hole of the bushing 4 forms a gas flow channel 41, the valve shaft 2 is rotatably connected to the housing 1 and passes through the bushing 4 and the gas flow channel 41 along the radial direction of the bushing 4, the valve plate 3 is installed on the valve shaft 2 and is located in the gas flow channel 41; the bushing 4 is used to prevent the condensed water generated by the gas flowing through the gas flow channel 41 from directly contacting the housing 1. The driving device is used to drive the valve shaft 2 to rotate, so as to drive the valve plate 3 to rotate around the axis of the valve shaft 2, and further adjust the gas flow area (the opening degree of the valve plate 3) of the gas flow channel 41. When the valve plate 3 closes the gas flow channel 41, the opening degree of the valve plate 3 is 0 (the gas flow area is 0). When the valve plate 3 is parallel to the axis of the gas flow channel 41, the opening degree of the valve plate 3 is the largest (the gas flow area is the largest). The main purpose of the EGR valve is to adjust the flow rate of the EGR gas entering the cylinder for combustion as needed by adjusting the opening degree of the valve plate 3 for the EGR gas cooled by the EGR cooler. If the opening angle of the valve plate 3 is different, the gas flow area of the gas flow channel 41 (EGR air passage) is different, so as to realize the adjustment of the EGR gas flow rate.

[0060] For the EGR valve provided by the embodiment of the present utility model, the bushing 4 is assembled in the through hole 11 of the housing 1, and the inner hole of the bushing 4 forms a gas flow channel 41 for the EGR gas to pass through. In this way, when the EGR gas passes through the EGR valve, the EGR gas does not directly contact the housing 1, and the condensed water generated when the EGR gas flows through the EGR valve (condensed water will be precipitated when the temperature of the EGR gas is lower than its dew point temperature) directly drips on the inner hole wall of the bushing 4. Therefore, the corrosion of the housing 1 of the EGR valve by the condensed water can be reduced.

[0061] The EGR valve of the present application is still applicable to the scenario where there is condensed water. The EGR gas can be cooled to a lower temperature, improving the thermal efficiency of the engine and broadening the vehicle use scenario.

[0062] In one embodiment, the valve plate 3 is a circular plate, the inner hole of the bushing 4 is a circular hole, and the diameter of the valve plate 3 is smaller than the diameter of the inner hole of the bushing 4, so that the valve plate 3 can rotate in the inner hole of the bushing 4. When the valve plate 3 completely closes the gas flow channel 41, the valve plate 3 is perpendicular to the axis of the inner hole of the bushing 4. When the valve plate 3 completely opens the gas flow channel 41, the valve plate 3 is parallel to the axis of the inner hole of the bushing 4. Preferably, the axis of the valve shaft 2 is perpendicular to the axis of the inner hole of the bushing 4.

[0063] In one embodiment, the outer peripheral surface of the bushing 4 is in close fit with the hole wall of the through hole 11. In this way, there is no gap between the outer peripheral surface of the bushing 4 and the hole wall of the through hole 11, and the outer peripheral surface of the bushing 4 and the hole wall of the through hole 11 are completely sealed, so that no gas or liquid can enter between the outer peripheral surface of the bushing 4 and the hole wall of the through hole 11, which can avoid the corrosion of the hole wall of the through hole by condensed water and further reduce the corrosion of the housing 1 of the EGR valve by condensed water.

[0064] In one embodiment, referring to Figure 2 , first sealing surfaces 111 and second sealing surfaces 112 are respectively formed at two axial ends of the through hole 11; the bushing 4 includes a bushing body 42, a first flange 43 and a second flange 44, the first flange 43 is connected to one axial end of the bushing body 42 and protrudes radially outward from the bushing body 42 along the bushing body 42, and the second flange 44 is connected to the other axial end of the bushing body 42 and protrudes radially outward from the bushing body 42 along the bushing body 42; the first flange 43 is in sealing fit with the first sealing surface 111, and the second flange 44 is in sealing fit with the second sealing surface 112. In this way, the first flange 43 and the second flange 44 of the bushing 4 can wrap the two axial ends of the through hole 11. When a sealing gasket is installed on the housing of the EGR valve, the sealing rib of one sealing gasket presses on the axial side end surface of the first flange 43 of the bushing 4 away from the second flange 44, and the sealing rib of the other sealing gasket presses on the axial side end surface of the second flange 44 of the bushing 4 away from the first flange 43.

[0065] In one embodiment, the bushing 4 is a stainless steel bushing. Since stainless steel has good corrosion resistance, the bushing 4 has good corrosion resistance, the bushing 4 itself is not easily corroded by condensed water, and it is difficult for condensed water to contact the housing 1 through the bushing 4, which can further reduce the corrosion of the housing 1 of the EGR valve by condensed water.

[0066] In this way, the sealing surface of the sealing gasket is a stainless steel surface, and condensed water will not corrode the sealing surface of the sealing gasket, which can avoid the sealing failure of the sealing gasket. If the sealing gaskets on both sides of the EGR valve are not tightly sealed, on the one hand, the leaked EGR gas will pollute the engine compartment; on the other hand, the amount of EGR gas actually entering the cylinder for combustion is also reduced, and the on-demand adjustment of the EGR gas flow cannot be achieved.

[0067] In one embodiment, a first convex ring 113 protruding inwardly of the through hole 11 is provided at one axial end of the through hole 11, and a second convex ring 114 protruding inwardly of the through hole 11 is provided at the other axial end of the through hole 11. An annular first groove is formed at the junction of the first flange 113 and the bushing body 42, and an annular second groove is formed at the junction of the second flange 114 and the bushing body 42. The first convex ring 113 is fitted into the first groove, and the second convex ring 114 is fitted into the second groove.

[0068] In one embodiment, referring to Figure 2 , the two surfaces of the housing 1 located on both axial sides of the through hole 11 are a first surface 12 and a second surface 13 respectively; the first surface 12 is spaced from the first convex ring 113 to form the first sealing surface 111 between the first convex ring 113 and the first surface 12. The first sealing surface 111 has a first radial portion extending in the radial direction of the bushing 4 and a first axial portion extending in the axial direction of the bushing 4; the second surface 13 is spaced from the second convex ring 114 to form the second sealing surface 112 between the second convex ring 114 and the second surface 13. The second sealing surface 112 has a second radial portion extending in the radial direction of the bushing 4 and a second axial portion extending in the axial direction of the bushing 4; the surface of the first flange 43 close to the first convex ring 113 along the axial direction of the bushing 4 fits with the first radial portion, and the outer peripheral surface of the first flange 43 fits with the first axial portion; the surface of the second flange 44 close to the second convex ring 114 along the axial direction of the bushing 4 fits with the second radial portion, and the outer peripheral surface of the second flange 44 fits with the second axial portion. In this way, the first flange 43 and the second flange 44 of the bushing 4 can completely wrap both axial ends of the through hole 11.

[0069] In one embodiment, the bushing 4 is integrally formed in the housing 1. Generally, the housing 1 is made of aluminum alloy and is formed by casting. The bushing 4 is pre-buried in the casting mold of the housing 1, and then molten aluminum is poured, so that the bushing 4 is integrally formed in the housing 1. The assembly steps of the bushing 4 and the housing 1 are reduced, the process is simpler, and the production efficiency is improved. At the same time, the first convex ring 113 and the second convex ring 114 are provided, so that after molding, the bushing 4 is firmly formed in the housing 1 and will not fall off. In one embodiment, the corrosion resistance of the bushing 4 is not lower than that of stainless steel of model SUS316L. For example, the bushing 4 is made of stainless steel of SUS316L or Ti alloy stainless steel. Stainless steel of SUS316L has good corrosion resistance.

[0070] In one embodiment, the valve shaft 2 and the valve plate 3 are made of stainless steel, and the corrosion resistance of the valve shaft 2 and the valve plate 3 is not lower than that of stainless steel of model SUS316L. For example, the valve shaft 2 and the valve plate 3 are made of stainless steel of SUS316L or Ti alloy stainless steel, etc. In addition, the valve plate 3 is mounted on the valve shaft 2 through bolts 5. The bolts 5 are preferably made of stainless steel.

[0071] In one embodiment, referring to Figure 2 , it further includes a first bearing 6, a second bearing 7, a first sealing structure 8 and a second sealing structure 9. The housing 1 is provided with a first mounting hole 14 and a second mounting hole 15 on opposite sides along the radial direction of the bushing 4; a first through hole 45 and a second through hole 46 penetrating along the radial direction of the bushing 4 are provided on the outer peripheral wall of the bushing 4. The first through hole 45 is connected between the gas flow passage 41 and the first mounting hole 14, and the second through hole 46 is connected between the gas flow passage 41 and the second mounting hole 15; the outer ring of the first bearing 6 is press-fitted into the first mounting hole 14, one axial end of the valve shaft 2 passes through the first through hole 45 and is press-fitted into the inner ring of the first bearing 6, the outer ring of the second bearing 7 is press-fitted into the second mounting hole 15, and the other axial end of the valve shaft 2 passes through the second through hole 46 and is press-fitted into the inner ring of the second bearing 7; the first sealing structure 8 is disposed between the inner ring of the first bearing 6 and the outer peripheral surface of the valve shaft 2 for sealing the gap between the inner ring of the first bearing 6 and the outer peripheral surface of the valve shaft 2; the second sealing structure 9 is disposed between the inner ring of the second bearing 7 and the outer peripheral surface of the valve shaft 2 for sealing the gap between the inner ring of the second bearing 7 and the outer peripheral surface of the valve shaft 2.

[0072] In this way, since the outer ring of the first bearing 6 is press-fitted into the first mounting hole 14, a seal is formed between the outer ring of the first bearing 6 and the hole wall of the first mounting hole 14, and the first sealing structure 8 seals the gap between the inner ring of the first bearing 6 and the outer peripheral surface of the valve shaft 2. Thus, the condensed water in the gas flow 41 that enters the inner ring of the first bearing 6 through the gap between the inner ring of the first bearing 6 and the outer peripheral surface of the valve shaft 2 is blocked by the first sealing structure 8, preventing the condensed water from corroding the housing 1 or other components inside the housing 1 of the EGR valve through the first bearing 6. And, since the outer ring of the second bearing 7 is press-fitted into the second mounting hole 15, a seal is formed between the outer ring of the second bearing 7 and the hole wall of the second mounting hole 15, and the second sealing structure 9 seals the gap between the inner ring of the second bearing 7 and the outer peripheral surface of the valve shaft 2. Thus, the condensed water in the gas flow 41 that enters the inner ring of the second bearing 7 through the gap between the inner ring of the second bearing 7 and the outer peripheral surface of the valve shaft 2 is blocked by the second sealing structure 9, preventing the condensed water from corroding the housing 1 or other components inside the housing 1 of the EGR valve through the second bearing 9.

[0073] In one embodiment, the first bearing 6 is a needle bearing, and the second bearing 7 is a needle bearing. The rollers of the needle bearing are needles. The needle bearing is a standard part, and there is no need to specially develop a bearing dedicated to the EGR valve of the present application, which has a low cost. Needle bearings are installed at both axial ends of the valve shaft 2, solving the problems of eccentric wear of the plastic bushing and valve plate offset of the existing EGR valve, which is beneficial to ensuring the uniformity of the EGR gas flow on both sides of the valve plate 3 in the gas flow passage 41, beneficial to improving the calibration accuracy of the EGR rate, and better realizing the on-demand adjustment of the EGR flow rate.

[0074] However, in other embodiments, it is also possible that the first bearing 6 is a ball bearing and the second bearing 7 is a ball bearing. The rollers of the ball bearing are balls.

[0075] However, in other embodiments, it is also possible that one of the first bearing 6 and the second bearing 7 is a ball bearing and the other is a needle bearing.

[0076] In one embodiment, referring to Figure 2 , the first sealing structure 8 includes a first sealing ring 81 and a second sealing ring 82. A first sealing groove is provided at one end of the inner ring of the first bearing 6 away from the second bearing 7, and a second sealing groove is provided at one end of the inner ring of the first bearing 6 close to the second bearing 7. The first sealing ring 81 is press-fitted into the first sealing groove, and the inner ring of the first sealing ring 81 is in sealing contact with the outer peripheral surface of the valve shaft 2. The second sealing ring 82 is press-fitted into the second sealing groove, and the inner ring of the second sealing ring 82 is in sealing contact with the outer peripheral surface of the valve shaft 2. Along the axial direction of the first bearing 6, the rollers of the first bearing 6 are located between the first sealing ring 81 and the second sealing ring 82. In this way, the condensed water that enters the inner ring of the first bearing 6 through the gap between the inner ring of the first bearing 6 and the outer peripheral surface of the valve shaft 2 in the gas flow 41 is blocked by the second sealing ring 82, preventing the condensed water from corroding the rollers of the first bearing 6 and preventing the first bearing 6 from getting stuck. In addition, the first sealing ring 81 can prevent foreign objects (such as dust) from entering the rollers of the first bearing 6 from one end of the first mounting hole 14 away from the bushing 4, preventing the second bearing 6 from getting stuck due to foreign objects. And it can also prevent the gas in the housing 1 from entering the gas flow passage 41 through the first bearing 6 from one end of the first mounting hole 14 away from the bushing 4, avoiding the influence of external gas on the EGR gas.

[0077] In one embodiment, referring to Figure 2, the second sealing structure 9 includes a third sealing ring 91 and a fourth sealing ring 92. A third sealing groove is provided at one end of the inner ring of the second bearing 7 away from the first bearing 6, and a fourth sealing groove is provided at one end of the inner ring of the second bearing 7 close to the first bearing 6. The third sealing ring 91 is press-fitted into the third sealing groove, and the inner ring of the third sealing ring 91 is in sealing contact with the outer peripheral surface of the valve shaft 2. The fourth sealing ring 92 is press-fitted into the fourth sealing groove, and the inner ring of the fourth sealing ring 92 is in sealing contact with the outer peripheral surface of the valve shaft 2. Along the axial direction of the second bearing 7, the rollers of the second bearing 7 are located between the third sealing ring 91 and the fourth sealing ring 92. In this way, the condensed water that enters the inner ring of the second bearing 7 through the gap between the inner ring of the second bearing 7 and the outer peripheral surface of the valve shaft 2 in the gas flow 41 is blocked by the fourth sealing ring 92, preventing the condensed water from corroding the rollers of the second bearing 7 and preventing the second bearing 7 from getting stuck. In addition, the third sealing ring 91 can prevent foreign objects (such as dust) from entering the rollers of the second bearing 7 from one end of the second mounting hole 15 away from the bushing 4, preventing the second bearing 7 from getting stuck due to foreign objects. Moreover, it can also prevent the gas outside the housing 1 from entering the gas flow path 41 through the second bearing 7 from one end of the second mounting hole 14 away from the bushing 4, avoiding the influence of external gas on the EGR gas.

[0078] In a preferred embodiment, there are two second sealing grooves, and two second sealing rings 82 are provided. Each second sealing ring 82 is press-fitted into the corresponding second sealing groove; that is, two seals are provided between the inner ring of the first bearing 6 and the outer peripheral surface of the valve shaft 2 at one end close to the bushing 4. The two seals can still play a sealing role when the first seal fails, further improving the sealing performance.

[0079] In a preferred embodiment, there are two fourth sealing grooves, and two fourth sealing rings 92 are provided. Each fourth sealing ring 92 is press-fitted into the corresponding fourth sealing groove. That is, two seals are provided between the inner ring of the second bearing 7 and the outer peripheral surface of the valve shaft 2 at one end close to the bushing 4. The two seals can still play a sealing role when the first seal fails, further improving the sealing performance.

[0080] In an embodiment, the outer ring and the inner ring of the first bearing 6 are made of stainless steel, and the corrosion resistance of the outer ring and the inner ring of the first bearing 6 is not lower than that of stainless steel of model SUS316L; for example, the outer ring and the inner ring of the first bearing 6 are made of SUS316L stainless steel or Ti alloy stainless steel, etc. The outer ring and the inner ring of the second bearing 7 are made of stainless steel, and the corrosion resistance of the outer ring and the inner ring of the second bearing 7 is not lower than that of stainless steel of model SUS316L. For example, the outer ring and the inner ring of the second bearing 7 are made of SUS316L stainless steel or Ti alloy stainless steel, etc.

[0081] Thus, in some embodiments, the components that may come into contact with the condensed water in the EGR valve (valve shaft 2, valve plate 3, bushing 4, inner and outer rings of the first bearing 6, inner and outer rings of the second bearing 7) are all made of stainless steel. This can prevent the various components of the EGR valve from being corroded by the condensed water.

[0082] In one embodiment, the valve shaft 2 is in clearance fit with the hole wall of the first through hole 45, and the valve shaft 2 is in clearance fit with the hole wall of the second through hole 46.

[0083] In one embodiment, referring to Figure 2 , the first through hole 45 includes a first large-diameter hole, a first small-diameter hole, and a first medium-diameter hole connecting the first large-diameter hole and the first small-diameter hole. The first large-diameter hole, the first medium-diameter hole, and the first small-diameter hole are all circular holes and their diameters decrease in sequence. A first limiting surface is formed at the connection of the first large-diameter hole and the first medium-diameter hole. One end of the first bearing 6 extends into the first large-diameter hole and abuts against the first limiting surface to achieve the axial one-end limiting of the first bearing 6. The second through hole 46 includes a second large-diameter hole, a second small-diameter hole, and a second medium-diameter hole connecting the second large-diameter hole and the second small-diameter hole. The second large-diameter hole, the second medium-diameter hole, and the second small-diameter hole are all circular holes and their diameters decrease in sequence. A second limiting surface is formed at the connection of the second large-diameter hole and the second medium-diameter hole. One end of the second bearing 7 extends into the second large-diameter hole 461 and abuts against the second limiting surface to achieve the axial one-end limiting of the second bearing 7.

[0084] In one embodiment, the clearance X1 between the hole wall of the first small-diameter hole and the valve shaft 2 is smaller than the clearance X2 between the first medium-diameter hole 453 and the valve shaft 2; stainless steel itself (such as SUS316L) has extremely strong corrosion resistance, and it is unlikely that the bushing 4 will be corroded by the condensed water in the EGR valve. However, to prevent the bushing or the valve shaft 2 from rusting and jamming in extreme cases, a clearance X2 is designed between the valve shaft 2 and the first through hole 45 of the bushing 4 to ensure that even if the valve shaft 2 and the bushing 4 rust, there is still a large tolerance space and it will not cause the jamming of the EGR valve, forming a secondary protection. On the other hand, considering that when the engine does not use EGR, the EGR valve is in the closed state at this time, but there is still a certain leakage at the valve plate 3 inevitably. If the leakage is too large, the engine will introduce too much EGR gas leaked from the valve plate 3 into the cylinder for combustion, causing unstable engine combustion or even flameout. Therefore, a clearance X1 smaller than X2 is provided on the side of the clearance X2 close to the gas flow passage 41.

[0085] In one embodiment, the clearance X3 between the hole wall of the second small-diameter hole and the valve shaft 2 is smaller than the clearance X4 between the second medium-diameter hole and the valve shaft 2. Stainless steel itself (such as SUS316L) has extremely strong corrosion resistance, and it is unlikely that the bushing 4 will be corroded by the condensate in the EGR valve. However, to prevent the bushing or the valve shaft 2 from rusting and jamming in extreme cases, a clearance X4 is designed between the valve shaft 2 and the second through hole 46 of the bushing 4 to ensure that even if the valve shaft 2 and the bushing 4 rust, there is still a large tolerance space and it will not cause the jamming of the EGR valve, forming a secondary protection. On the other hand, considering that when the engine does not use EGR, the EGR valve is in the closed state at this time, but there is still a certain leakage at the valve plate 3 inevitably. If the leakage is too large, the engine will introduce too much EGR gas leaked from the valve plate 3 into the cylinder to participate in combustion, causing unstable engine combustion or even flameout. Therefore, a clearance X3 smaller than X4 is provided on the side of the clearance X4 close to the gas flow passage 41.

[0086] In one embodiment, referring to Figure 2 , the second mounting hole 15 includes a connected first hole section 151 and a second hole section 152. The first hole section 151 is connected between the second through hole 46 and the second hole section 152. The second hole section 152 penetrates through the housing 1. A plug 10 for blocking the second mounting hole 15 is provided in the second hole section 152, and the axial other end of the valve shaft 2 is located inside the plug 10.

[0087] In one embodiment, referring to Figure 2 , a valve plate mounting groove is provided on the part of the valve shaft 2 located in the gas flow passage 41. The valve plate mounting groove penetrates through the valve shaft 2 along the radial direction of the valve shaft 2, and the valve plate 3 is inserted into the valve plate mounting groove. The valve shaft 2 is provided with a threaded hole along its radial direction, and the valve plate 3 is provided with a bolt through hole. The bolt 5 is threadedly connected to the threaded hole and passes through the bolt through hole to fix the valve plate 3 on the valve shaft 2.

[0088] In one embodiment, referring to Figure 3 , the driving device includes a motor 20 and a transmission mechanism 30. The motor 20 and the transmission mechanism 30 are mounted on the housing 1, and the transmission mechanism 30 is connected between the axial one end of the valve shaft 2 and the output shaft of the motor 20; the motor 20 is used to drive the valve shaft 2 to rotate through the transmission mechanism 30.

[0089] In one embodiment, referring to Figure 3, the transmission mechanism 30 is a gear transmission mechanism. The transmission mechanism 30 includes a motor gear 301, an intermediate gear 302, and a drive gear 303. The motor gear 301 is fixed on the output shaft of the motor 20, the drive gear 303 is fixed on the valve shaft 2, and the intermediate gear 302 is meshed between the motor gear 301 and the drive gear 303. Specifically, the intermediate gear 302 includes a large gear 3021 and a small gear 3022 connected coaxially. The motor gear 301 is meshed with the large gear 3021, and the drive gear 303 is meshed with the small gear 3022.

[0090] In one embodiment, referring to Figure 3 , the housing 1 includes a main housing 16 and an outer cover 17. The outer cover 17 is connected to the main housing 16 to form a transmission mechanism installation cavity therebetween. The transmission mechanism 30 is accommodated in the transmission mechanism installation cavity. The main housing 16 includes an air passage portion 161 and a motor installation portion 162. The through hole 11 is formed in the air passage portion 161. The valve shaft 2 is rotatably connected to the air passage portion 161. The motor installation portion 162 forms a motor installation cavity, and the motor 20 is accommodated in the motor installation cavity.

[0091] However, in other embodiments, the transmission mechanism 30 can also be a belt transmission mechanism or a chain transmission mechanism.

[0092] In other embodiments, a corrosion-resistant layer is provided on the surface of the bushing 4. At this time, the bushing 4 may not be made of stainless steel, for example, made of plastic, etc. Through the corrosion-resistant layer provided on the surface of the plastic, the bushing 4 has good corrosion resistance. In this way, the bushing 4 itself is not easily corroded by condensed water, and it is difficult for condensed water to contact the housing 1 through the bushing 4, which can reduce the corrosion of the housing 1 of the EGR valve by condensed water. The corrosion-resistant layer can be, for example, a stainless steel layer.

[0093] In addition, an embodiment of the present invention provides an engine assembly, including an engine and the EGR valve of the above embodiment. The gas flow passage 41 is connected between the exhaust pipe and the intake pipe of the engine.

[0094] In addition, an embodiment of the present invention provides a vehicle, including the EGR valve of the above embodiment or the engine assembly of the above embodiment.

[0095] The vehicle can be a fuel vehicle or a hybrid vehicle (range-extended or plug-in).

[0096] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An EGR valve, characterized in that, It includes a housing, a driving device, a valve shaft, a valve plate and a bushing. The housing is provided with a through hole, the bushing is assembled in the through hole, the inner hole of the bushing forms a gas flow passage, the valve shaft is rotatably connected to the housing and passes through the bushing and the gas flow passage along the radial direction of the bushing, and the valve plate is installed on the valve shaft and located in the gas flow passage; the bushing is used to prevent the condensed water generated by the gas flowing through the gas flow passage from directly contacting the housing. The driving device is used to drive the valve shaft to rotate, so as to drive the valve plate to rotate around the axis of the valve shaft, and further adjust the gas flow area of the gas flow passage.

2. The EGR valve according to claim 1, characterized in that, The outer peripheral surface of the bushing is in close fit with the hole wall of the through hole.

3. The EGR valve according to claim 2, wherein First sealing surfaces and second sealing surfaces are respectively formed at both axial ends of the through hole. The bushing includes a bushing body, a first flange and a second flange. The first flange is connected to one axial end of the bushing body and protrudes radially outward from the bushing body along the radial direction of the bushing body. The second flange is connected to the other axial end of the bushing body and protrudes radially outward from the bushing body along the radial direction of the bushing body. The first flange is in sealing fit with the first sealing surface, and the second flange is in sealing fit with the second sealing surface.

4. The EGR valve according to claim 3, characterized in that, A first convex ring protruding inwardly from the through hole is provided at one axial end of the through hole, and a second convex ring protruding inwardly from the through hole is provided at the other axial end of the through hole. An annular first groove is formed at the joint of the first flange and the bushing body, and an annular second groove is formed at the joint of the second flange and the bushing body. The first convex ring is fitted in the first groove, and the second convex ring is fitted in the second groove.

5. The EGR valve according to claim 4, wherein The surfaces of the housing on both axial sides of the through hole are respectively a first surface and a second surface. The first surface is spaced from the first convex ring to form the first sealing surface between the first convex ring and the first surface. The first sealing surface has a first radial part extending along the radial direction of the bushing and a first axial part extending along the axial direction of the bushing. The second surface is spaced from the second convex ring to form the second sealing surface between the second convex ring and the second surface. The second sealing surface has a second radial part extending along the radial direction of the bushing and a second axial part extending along the axial direction of the bushing. The surface of the first flange along the axial direction of the bushing close to the first convex ring is in fit with the first radial part, and the outer peripheral surface of the first flange is in fit with the first axial part. The surface of the second flange along the axial direction of the bushing close to the second convex ring is in fit with the second radial part, and the outer peripheral surface of the second flange is in fit with the second axial part.

6. The EGR valve according to claim 1, characterized in that, The bushing is a stainless steel bushing.

7. The EGR valve according to claim 1, wherein The bushing is integrally formed in the housing. and / or The housing is made of aluminum alloy.

8. The EGR valve according to claim 6, characterized in that, The corrosion resistance of the bushing is not lower than that of stainless steel of model SUS316L. and / or The valve shaft and the valve plate are made of stainless steel, and the corrosion resistance of the valve shaft and the valve plate is not lower than that of stainless steel of model SUS316L.

9. The EGR valve according to claim 1, characterized in that, It further includes a first bearing, a second bearing, a first sealing structure and a second sealing structure. The housing is provided with a first mounting hole and a second mounting hole on opposite sides along the radial direction of the bushing. The outer peripheral wall of the bushing is provided with a first through hole and a second through hole penetrating along the radial direction of the bushing. The first through hole is connected between the gas flow channel and the first mounting hole, and the second through hole is connected between the gas flow channel and the second mounting hole. The outer ring of the first bearing is press-fitted into the first mounting hole. One axial end of the valve shaft passes through the first through hole and is press-fitted into the inner ring of the first bearing. The outer ring of the second bearing is press-fitted into the second mounting hole. The other axial end of the valve shaft passes through the second through hole and is press-fitted into the inner ring of the second bearing. The first sealing structure is arranged between the inner ring of the first bearing and the outer peripheral surface of the valve shaft to seal the gap between the inner ring of the first bearing and the outer peripheral surface of the valve shaft. The second sealing structure is arranged between the inner ring of the second bearing and the outer peripheral surface of the valve shaft to seal the gap between the inner ring of the second bearing and the outer peripheral surface of the valve shaft.

10. The EGR valve according to claim 9, characterized in that, The first bearing is a needle bearing. and / or The second bearing is a needle bearing.

11. The EGR valve according to claim 9, characterized in that, The first sealing structure includes a first sealing ring and a second sealing ring. One end of the inner ring of the first bearing away from the second bearing is provided with a first sealing groove, and one end of the inner ring of the first bearing close to the second bearing is provided with a second sealing groove. The first sealing ring is press-fitted into the first sealing groove, and the inner ring of the first sealing ring is in sealing contact with the outer peripheral surface of the valve shaft. The second sealing ring is press-fitted into the second sealing groove, and the inner ring of the second sealing ring is in sealing contact with the outer peripheral surface of the valve shaft. Along the axial direction of the first bearing, the rollers of the first bearing are located between the first sealing ring and the second sealing ring. The second sealing structure includes a third sealing ring and a fourth sealing ring. One end of the inner ring of the second bearing away from the first bearing is provided with a third sealing groove, and one end of the inner ring of the second bearing close to the first bearing is provided with a fourth sealing groove. The third sealing ring is press-fitted into the third sealing groove, and the inner ring of the third sealing ring is in sealing contact with the outer peripheral surface of the valve shaft. The fourth sealing ring is press-fitted into the fourth sealing groove, and the inner ring of the fourth sealing ring is in sealing contact with the outer peripheral surface of the valve shaft. Along the axial direction of the second bearing, the rollers of the second bearing are located between the third sealing ring and the fourth sealing ring.

12. The EGR valve according to claim 11, characterized in that, There are two second sealing grooves and two second sealing rings, and each second sealing ring is press-fitted into the corresponding second sealing groove. and / or There are two fourth sealing grooves and two fourth sealing rings, and each fourth sealing ring is press-fitted into the corresponding fourth sealing groove.

13. The EGR valve according to claim 9, wherein The outer ring and the inner ring of the first bearing are made of stainless steel, and the corrosion resistance of the outer ring and the inner ring of the first bearing is not lower than that of stainless steel of model SUS316L. and / or The outer ring and inner ring of the first bearing are made of stainless steel, and the corrosion resistance of the outer ring and inner ring of the second bearing is not less than that of stainless steel of model SUS316L.

14. The EGR valve according to claim 9, wherein, The valve shaft is in clearance fit with the hole wall of the first through hole and the valve shaft is in clearance fit with the hole wall of the second through hole.

15. The EGR valve according to claim 14, wherein The first through hole includes a first large-diameter hole, a first small-diameter hole, and a first medium-diameter hole connecting the first large-diameter hole and the first small-diameter hole. The first large-diameter hole, the first medium-diameter hole, and the first small-diameter hole are all circular holes and the diameters decrease in sequence. A first limiting surface is formed at the junction of the first large-diameter hole and the first medium-diameter hole. One end of the first bearing extends into the first large-diameter hole and abuts against the first limiting surface. The second through hole includes a second large-diameter hole, a second small-diameter hole, and a second medium-diameter hole connecting the second large-diameter hole and the second small-diameter hole. The second large-diameter hole, the second medium-diameter hole, and the second small-diameter hole are all circular holes and the diameters decrease in sequence. A second limiting surface is formed at the junction of the second large-diameter hole and the second medium-diameter hole. One end of the second bearing extends into the second large-diameter hole and abuts against the second limiting surface.

16. The EGR valve according to claim 15, characterized in that, The clearance between the hole wall of the first small-diameter hole and the valve shaft is smaller than the clearance between the first medium-diameter hole and the valve shaft. The clearance between the hole wall of the second small-diameter hole and the valve shaft is smaller than the clearance between the second medium-diameter hole and the valve shaft.

17. The EGR valve according to claim 9, characterized in that, The second mounting hole includes an adjacent first hole section and a second hole section. The first hole section is connected between the second through hole and the second hole section. The second hole section penetrates through the housing. A plug for blocking the second mounting hole is provided in the second hole section. The other axial end of the valve shaft is located inside the plug.

18. The EGR valve according to claim 1, characterized in that, A valve plate mounting groove is provided on the part of the valve shaft located in the gas flow channel. The valve plate mounting groove penetrates through the valve shaft along the radial direction of the valve shaft, and the valve plate is inserted into the valve plate mounting groove.

19. The EGR valve according to claim 1, wherein, The surface of the bushing is provided with a corrosion-resistant layer.

20. The EGR valve according to any one of claims 1-19, characterized in that, The driving device includes a motor and a transmission mechanism. The motor and the transmission mechanism are mounted on the housing, and the transmission mechanism is connected between one axial end of the valve shaft and the output shaft of the motor. The motor is used to drive the valve shaft to rotate through the transmission mechanism.

21. The EGR valve according to claim 20, characterized in that, The housing includes a main housing and an outer cover. The outer cover is connected to the main housing to form a transmission mechanism installation cavity therebetween. The transmission mechanism is accommodated in the transmission mechanism installation cavity. The main housing includes an air passage part and a motor installation part. The through hole is formed in the air passage part. The valve shaft is rotatably connected to the air passage part. The motor installation part forms a motor installation cavity, and the motor is accommodated in the motor installation cavity.

22. An engine assembly, characterized in that, An engine and an EGR valve according to any one of claims 1-21, wherein the gas flow channel is connected between the exhaust pipe and the intake pipe of the engine.

23. A vehicle, characterized in that, An EGR valve according to any one of claims 1-21 or an engine assembly according to claim 22.

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