Plunger sleeve structure of multi-stage sealing ring of oil feed pump and oil pumping system assembly

Abstract

The invention belongs to the technical field of mechanical pump oil systems, and particularly discloses a plunger sleeve structure of a multi-stage sealing ring of an oil feed pump, which comprises a pump body provided with a fuel oil cavity and a plunger sleeve sleeved on the fuel oil cavity, at least two annular grooves are formed in the outer side of the plunger sleeve at intervals, and each annular groove is provided with a sealing ring. And the lower edge position of the ring groove close to the fuel cavity and the inner wall of the fuel cavity form a pressure reducing ring belt for reducing oil pressure. The plunger sleeve is provided with the multiple sealing rings and the pressure reduction ring belts, so that the sealing rings close to the fuel oil cavity are suitable for the complex environment, the pressure impact of high-pressure oil in the fuel oil cavity is reduced, the frequency of damage and abnormal deformation of the sealing rings is reduced, and the reliability of the sealing rings is improved. The invention further discloses an oil pumping system assembly.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechanical pump oil systems, and particularly relates to a plunger sleeve structure with multi-stage sealing rings for an oil supply pump and an oil pump system assembly. Background Art

[0002] As the core power source for modern industrial operation, the technical level of engines deeply affects a country's international competitiveness in key industries such as aviation, automobiles, ships, industrial machinery, and agricultural machinery. As one of the heart components of an engine, mechanical oil supply pumps are commonly used in high-pressure and large-flow oil supply pump oil circuits.

[0003] Existing mechanical oil supply pumps mostly adopt a suspended plunger sleeve layout scheme, such as Figure 2 shown. The plunger sleeve has a main sealing ring for sealing the installation gap between the plunger sleeve and the pump body. Its main purpose is to prevent fuel leakage inside the mechanical oil supply pump and the entry of impurities, gases, etc. from the external environment, thereby improving the safety of the engine. However, mechanical oil supply pumps are mainly used in harsh operating environments and complex climatic conditions such as marine power, mining machinery, and freight transportation. After long-term use, the following problems exist:

[0004] 1. For the sealing ring 3 of the plunger sleeve 2, considering dust and water prevention, the installation position of the sealing ring 3 is designed to be relatively far from the end face of the pump body 1. To a certain extent, this can delay the time of being damaged by impurities or corrosive gases. However, this results in a large volume of impurities and corrosive gases deposited in the first region 13, which is not conducive to maintaining the sealing function of the sealing ring 3. Specifically, after particulate impurities, corrosive gases, and water vapor in the external environment enter the position of the sealing ring 3 through the gap between the plunger sleeve and the pump body, the particulate impurities will rub against the sealing ring 3 or adhere to the sealing ring 3, leading to oil leakage after the sealing ring 3 is damaged. Secondly, the corrosive gases or water vapor deposited in the position of the sealing ring 3 cannot be effectively removed, resulting in an electrochemical reaction that corrodes the surfaces of the plunger sleeve 2 and the pump body 1. In the long term, the sealing of the sealing ring 3 will fail and cause oil leakage.

[0005] 2. The lower part of the sealing ring 3 is connected to the fuel chamber 111 of the oil pump system. The relatively high-pressure fuel in the fuel chamber 111 will directly impact the sealing ring 3 upward through the gap between the plunger sleeve 2 and the pump body 1, causing damage to the sealing ring 3 and thus leading to sealing failure. Summary of the Invention

[0006] The purpose of the present invention is to provide a plunger sleeve structure with multi-stage sealing rings for an oil supply pump, which can enhance the sealing function of the plunger sleeve sealing ring, improve the reliability of the plunger sleeve and the pump body in complex environments, and effectively extend their service life.

[0007] The object of the present invention is achieved by such a technical solution, and specifically provides a plunger sleeve structure for a multi-stage sealing ring of a fuel supply pump, including: a pump body provided with a fuel chamber and a plunger sleeve sleeved on the fuel chamber; at least two annular grooves are provided at intervals on the outer side of the plunger sleeve, and each annular groove is provided with a sealing ring; the lower edge position of the annular groove close to the fuel chamber and the inner wall of the fuel chamber form a pressure-reducing annular zone for reducing the oil pressure.

[0008] A multi-stage sealing ring is arranged on the outer side of the plunger sleeve, so that the sealing ring close to the fuel chamber reduces the influence of external particulate impurities, corrosive gases and water vapor, etc., ensures the normal function of the sealing ring close to the fuel chamber, and improves the sealing efficiency; a pressure-reducing annular zone is arranged to form a slit effect, so that the pressure impact of the high-pressure oil in the fuel chamber on the sealing ring close to the fuel chamber is weakened, the frequency of breakage and abnormal deformation of the sealing ring close to the fuel chamber is reduced, and its reliability is improved.

[0009] Preferably, the pressure-reducing annular zone includes a buffer zone, a pressure-reducing zone and a flow-reducing zone arranged in sequence from the sealing ring to the fuel chamber; the length of the pressure-reducing zone is h, the width is t, the value of h is not less than 1.2 mm, and the value of t is 0.05 - 0.1 mm.

[0010] Preferably, the cross-section of the sealing ring close to the fuel chamber is elliptical, and the remaining sealing rings are one of elliptical, circular or frustum-shaped.

[0011] Preferably, it further includes a circlip and an oil baffle ring. A circlip groove is further provided on the outer side of the plunger sleeve, the circlip is installed in the circlip groove, the plunger sleeve is provided with a step surface, the oil baffle ring is arranged on the outer side of the plunger sleeve, and one end of the oil baffle ring abuts against the step surface and the other end abuts against one end of the circlip.

[0012] Preferably, the circlip groove is an inclined surface and is in arc transition with the end face close to the oil baffle ring.

[0013] Preferably, the upper and lower end faces of the oil baffle ring are flat surfaces, the oil baffle ring is provided with end heads, the end heads are arc-inwardly recessed closing structures, and a plurality of oil inlet and return holes are evenly arranged at intervals along the circumferential direction of the oil baffle ring.

[0014] Preferably, the plunger sleeve is provided with plunger sleeve oil inlet and return holes communicated with the oil inlet and return holes, and the oil inlet and return holes are located below the plunger sleeve oil inlet and return holes.

[0015] Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0016] A plurality of sealing rings and a pressure-reducing annular zone are arranged on the plunger sleeve, so that the sealing ring close to the fuel chamber is suitable for a complex environment, the pressure impact of the high-pressure oil in the fuel chamber on the sealing ring is weakened, the frequency of breakage and abnormal deformation is reduced, and the reliability of the sealing ring is improved.

[0017] Another object of the present invention is to provide a fuel supply system assembly for a fuel pump, which has a long service life of the sealing ring and good reliability, and can better ensure that the working pressure of the mechanical injector is within the set range.

[0018] Another object of the present invention is achieved by the following technical solution. Specifically, a fuel supply system assembly for a fuel pump is provided, which includes a plunger sleeve structure with multi-stage sealing rings of the fuel pump and a plunger and an outlet valve assembly installed in the plunger sleeve.

[0019] Preferably, the outlet valve assembly includes an outlet valve seat assembly and an outlet valve core assembly. The outlet valve core assembly includes an outlet valve core body, a valve seat, a spring, a spring seat, and a steel ball. The outlet valve core body is in interference fit with the valve seat, and a third installation cavity is formed therebetween. The spring, the spring seat, and the steel ball are installed in the third installation cavity. One end of the spring abuts against the spring seat, and the other end abuts against the valve seat. The outlet valve seat assembly is provided with a fuel passage, and the steel ball is used to open or close the communication between the third installation cavity and the fuel passage.

[0020] Preferably, the outlet valve seat assembly includes an outlet valve holder, an outlet valve spring seat, an adjusting gasket, an outlet valve spring, and an outlet valve seat. The two ends of the outlet valve holder are provided with threads. The outlet valve holder and the outlet valve seat are provided with a coaxial through fourth installation cavity. The outlet valve spring seat, the adjusting gasket, the outlet valve spring, and the outlet valve core assembly are sequentially installed in the fourth installation cavity. One end of the outlet valve spring abuts against the adjusting gasket, and the other end abuts against the outlet valve core assembly.

[0021] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0022] By providing multi-stage sealing rings, the fuel supply system assembly can be used in a complex environment for a long time, improving the reliability of its sealing rings and extending the service life. By providing the outlet valve core assembly, the working pressure of the mechanical injector can be ensured to be within the set range. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for the specific embodiments will be briefly introduced below. In all the drawings, the elements or parts are not necessarily drawn to actual scale.

[0024] Figure 1 It is a schematic structural diagram of a plunger sleeve structure with multi-stage sealing rings of a fuel pump and a fuel supply system assembly of the present invention;

[0025] Figure 2 It is a schematic structural diagram of a plunger sleeve in the prior art;

[0026] Figure 3 It is a schematic diagram of a plunger sleeve structure with multi-stage sealing rings of a fuel pump;

[0027] Figure 4 It is an enlarged schematic diagram of a decompression ring belt;

[0028] Figure 5 It is a schematic diagram of the difference in the outer diameter of two levels;

[0029] Figure 6 It is a schematic diagram of the installation of the oil baffle ring;

[0030] Figure 7 It is a schematic diagram of the oil baffle ring;

[0031] Figure 8 It is a schematic diagram of the structure of the oil outlet valve core assembly;

[0032] Figure 9 It is a schematic diagram of the structure of the oil outlet valve seat assembly;

[0033] Figure 10 It is a schematic diagram of the effective oil pressure stroke P of the plunger;

[0034] Figure 11 It is a schematic diagram of the oil suction stage;

[0035] Figure 12 It is a schematic diagram of the oil pressure stage;

[0036] Figure 13 It is a schematic diagram of the oil drain stage.

[0037] Reference numerals:

[0038] 1 - Pump body, 11 - First installation cavity, 111 - Fuel cavity, 12 - Decompression ring belt, 121 - Buffer area, 122 - Decompression area, 123 - Discharge reduction area, 13 - First spatial area, 14 - Second spatial area, 15 - Phase adjustment gasket, 16 - Fuel inlet channel, 17 - Main fuel return channel, 18 - Fuel leakage return channel;

[0039] 2 - Plunger sleeve, 21 - Ring groove, 22 - Step surface, 23 - Circlip groove, 24 - Plunger sleeve inlet and return oil hole, 25 - Second installation cavity; 26 - Oil pressure chamber;

[0040] 3 - Sealing ring, 31 - First sealing ring, 32 - Second sealing ring;

[0041] 4 - Circlip;

[0042] 5 - Oil baffle ring, 51 - End, 52 - Inlet and return oil hole, 53 - Clearance oil storage chamber;

[0043] 6 - Plunger, 61 - Oil drain groove, 62 - Oil control bevel;

[0044] 7 - Oil outlet valve seat assembly, 71 - Oil valve retaining seat, 711 - Fourth installation cavity, 72 - Oil outlet valve spring seat, 73 - Adjusting gasket, 74 - Oil outlet valve spring, 75 - Oil outlet valve seat, 76 - Fuel channel;

[0045] 8 - Oil outlet valve core assembly, 81 - Oil outlet valve core body, 811 - Oil passage, 82 - Valve seat, 821 - Through hole, 822 - Conical cavity, 83 - Spring, 84 - Spring seat, 841 - Arc-shaped groove, 85 - Steel ball, 86 - Third installation cavity;

[0046] 9 - Oil outlet valve assembly. Specific embodiments

[0047] The embodiments of the technical solution of the present invention will be described in detail below with reference to the accompanying drawings.

[0048] Please refer to Figure 1 and Figure 3, A plunger sleeve structure of a multi-stage sealing ring for a fuel supply pump, comprising: a pump body 1 provided with a fuel chamber 111 and a plunger sleeve 2 sleeved on the fuel chamber 111; at least two annular grooves 21 are provided at intervals on the outer side of the plunger sleeve 2, and a sealing ring 3 is installed in each annular groove 21; the lower edge position of the annular groove 21 close to the fuel chamber 111 and the inner wall of the fuel chamber 111 form a pressure-reducing annular belt 12 for reducing oil pressure. Specifically, the pump body 1 is provided with a first installation cavity 11 for hanging and installing the plunger sleeve 2, and the fuel chamber 111 is arranged in the first installation cavity 11. At least two parallel annular grooves 21 are provided at intervals along the axial outer side of the plunger sleeve 2, and a sealing ring 3 is installed in each annular groove 21. Preferably, the material of the sealing ring 3 is fluorosilicone rubber, and there are two annular grooves 21, which are respectively installed with a first sealing ring 31 and a second sealing ring 32. A phase adjustment gasket 15 is provided between the end faces of the plunger sleeve 2 and the pump body 1. After installation, a first space area 13 is formed among the plunger sleeve 2, the phase adjustment gasket 15, the pump body 1 and the first sealing ring 31, and a second space area 14 is formed among the first sealing ring 31, the plunger sleeve 2, the pump body 1 and the second sealing ring 32. In a harsh use environment and a complex climate environment, external particulate impurities, corrosive gases and water vapor enter the first space area 13 through the gap between the plunger sleeve 2 and the pump body 1 and deposit. Because after the plunger sleeve 2 is installed in the first installation cavity 11, the first sealing ring 31 deforms, the first sealing ring 31 fills in the annular groove 21, and the first sealing ring 31 is closer to the end face of the pump body 1 than in the prior art, to a certain extent, the volume of impurity and corrosive gas deposition is reduced, the sealing aging of the first sealing ring 31 is improved, and the channel for particulate impurities, corrosive gases and water vapor to continue to invade the second space area 14 downward is effectively blocked, thereby ensuring that the second space area 14 is in a relatively closed environment. There is no intrusion of corrosive gas or water vapor in the second space area 14, and no electrochemical reaction will occur in this area, ensuring that the plunger sleeve 2 and the pump body 1 are not corroded. At the same time, the relatively closed environment also ensures that the second sealing ring 32 does not undergo material deterioration and impurity pollution, so as to ensure the normal function of the second sealing ring 32 and improve the sealing aging. A pressure-reducing annular belt 12 is formed among the second sealing ring 32, the plunger sleeve 2 and the pump body 1. The pressure-reducing annular belt 12 is an annular slit, which avoids the direct impact of the higher fuel pressure in the fuel chamber 111 on the second sealing ring 32. When the fuel in the fuel chamber 111 passes through the pressure-reducing annular belt 12, due to the obvious reduction of the gap between the pressure-reducing annular belt 12 and the pump body 1, a slit effect is formed. When the fuel passes through the pressure-reducing annular belt 12, the flow rate increases but the pressure decreases, so that the pressure impact of the high-pressure oil on the second sealing ring 32 is weakened, the frequency of breakage and abnormal deformation of the second sealing ring 32 is reduced, and the reliability of the second sealing ring 32 is improved.

[0049] Further, please refer to Figures 3 to 5, the pressure relief ring belt 12 includes a buffer area 121, a pressure relief area 122, and a flow reduction area 123 arranged in sequence from the sealing ring 3 to the fuel chamber 111. The length of the pressure relief area 122 is h, and the width is t. The value of h is not less than 1.2 mm, and the value of t is 0.05 - 0.1 mm. Specifically, the outer diameter of the upper edge position of the annular groove 21 close to the fuel chamber 111 is designed to be the same as that of other annular grooves 21, and its diameter is φA; the outer diameter of the lower edge position of the annular groove 21 close to the fuel chamber 111 is designed to be different from that of other annular grooves 21, and the outer diameter is φB. The diameter difference formed by the two-stage outer diameters is △a (△a = ΦB - ΦA). The length from the lower edge position of the annular groove 21 close to the fuel chamber 111 to the fuel chamber 111 is h. After the plunger sleeve 2 and the pump body 1 are assembled, the fit clearance formed by the outer diameter of the lower edge position of the annular groove 21 close to the fuel chamber 111 and the first installation cavity 11 (inner diameter is φC) is t (t = ΦC - φB). Therefore, an annular belt area with a length of h and a width of t is formed between the plunger sleeve 2 and the pump body 1 as the pressure relief area 122. The diameter of the plunger sleeve 2 gradually decreases from the lower end of the pressure relief area to the fuel chamber 111, forming the flow reduction area 123; the diameter of the plunger sleeve 2 gradually decreases from the upper end of the pressure relief area to the inner wall of the annular groove 21 and transitions in an arc shape, forming the buffer area 121. Designing a two-stage outer diameter structure with a diameter difference of △a on the plunger sleeve 2 and forming an annular pressure relief ring belt 12 after being installed and fitted with the pump body 1 aims to form an annular pressure relief area 122 with a length of h and a width of t between the plunger sleeve 2 and the pump body 1 after assembly. The pressure relief area 122 is an annular slit. Using the pressure relief area 122 can significantly reduce the impact pressure of the fuel in the fuel chamber 111 rushing into the pressure relief ring belt 12, reduce the impact force of the fuel on the sealing ring 3 close to the fuel chamber 111, and ensure that the sealing ring 3 does not break or deform abnormally. The cross-section of the flow reduction area 123 is frustum-shaped, enabling limited fuel to reach the pressure relief area 122 through the flow reduction area 123. At the same time, the fuel is affected by the frustum-shaped outer wall of the plunger sleeve 2, weakening the impact force of the fuel. The fuel reaches the buffer area 121 through the pressure relief area 122. After installing the sealing ring 3 in the annular groove 21, a buffer area 121 is formed in the limited space, increasing the volume of the annular groove 21 close to the pressure relief area 122 and having a buffer and pressure relief effect on the incoming fuel. Preferably, the value of △a is 0.5 mm. If the value of t is less than 0.05 mm, the machining accuracy of the plunger sleeve 2 and the pump body 1 is high, and the machining cost is high; if the value of t is greater than 0.1 mm, the slit effect is poor. If h is less than 1.2 mm, the fuel has passed through the pressure relief area 122 and entered the buffer area 121 before being decompressed, and the slit effect is poor.

[0050] Further, please refer to Figure 1, the cross-section of the sealing ring 3 near the fuel chamber 111 is elliptical, and the other sealing rings 3 are one of elliptical, circular or frustum-shaped. Specifically, the cross-section of the sealing ring 3 near the fuel chamber 111 is elliptical, which increases the contact area between the sealing ring and the first installation cavity 11 or the annular groove 21, thereby enhancing the resistance to fuel pressure.

[0051] Furthermore, please refer to Figure 1 and Figure 6 , it further includes a snap ring 4 and an oil baffle 5. There is also a snap ring groove 23 provided on the outer side of the plunger sleeve 2. The snap ring 4 is installed in the snap ring groove 23. The plunger sleeve 2 is provided with a stepped surface 22. The oil baffle 5 is arranged on the outer side of the plunger sleeve 2, and one end of the oil baffle 5 abuts against the stepped surface 22, and the other end abuts against one end of the snap ring 4. Specifically, the lower edge of the reduction area 123 is horizontal with the stepped surface 22. The oil baffle 5 is arranged in the fuel chamber 111. One end of the snap ring 4 abuts against the end face of the oil baffle 5, and the other end of the snap ring 4 abuts against the inner wall of the snap ring groove 23. The snap ring 4 generates a continuous pre-tightening force on the oil baffle 5, and the oil baffle 5 is installed between the stepped surface 22 and the snap ring 4.

[0052] Furthermore, the snap ring groove 23 is an inclined surface and has a circular arc transition with the end face near the oil baffle 5. With this structure, the snap ring 4 can receive a component force upward along the slope of the inclined surface after installation, so that the snap ring 4 is always in the snap ring groove 23 and generates a continuous pressure on the oil baffle 5, dynamically compensating for the machining deviation of the length dimension of the oil baffle 5 or the wear amount generated after the parts are used, ensuring that the upper plane of the oil baffle 5 is always in close contact with the stepped surface 22, and guaranteeing the assembly and use stability of the oil baffle 5. During use, the high-pressure fuel ejected during the oil discharge stage will directly impact the oil baffle 5, causing axial and radial displacements of the oil baffle 5. The oil baffle 5 is axially forced to push the snap ring 4 in the opposite direction, and the snap ring 4 will move downward along the slope of the inclined surface of the snap ring groove 23. During the downward displacement process, the inclined surface will generate a reaction force on the snap ring 4 to prevent the snap ring 4 from falling off after being impacted. At the same time, this reaction force changes with the different slopes of the inclined surface, and the force change amplitude of the snap ring 4 is not drastic, improving the working reliability and fatigue life of the snap ring 4. Through the acting force of the snap ring 4, the impact force received by the oil baffle 5 is buffered, ensuring the assembly and use stability of the oil baffle 5. The cross-section of the snap ring 4 is circular, and the snap ring groove 23 is provided with a circular arc transition to increase the contact area. The snap ring 4 can be better accommodated in the snap ring groove 23.

[0053] Furthermore, please refer to Figure 6 and Figure 7The upper and lower end faces of the oil deflector 5 are planes, and the oil deflector 5 is provided with an end head 51, which is a circular arc concave closing structure, and the oil deflector 5 is evenly spaced along its circumference. Specifically, compared with the oil deflector with a conical end face in the prior art, the upper and lower end faces of the oil deflector 5 are planes, and the four corners of the oil deflector 5 are provided with end heads 51, which are designed as a circular arc concave closing structure, which can not only reduce the matching clearance with the outer circle of the plunger sleeve 2, but also reduce the shaking amplitude of the oil deflector 5 under the impact of oil pressure, and play a positioning role; and the end head 51 of the oil deflector 5 has a small space and a large space in the middle, so that after assembly, a gap oil storage chamber 53 can be formed between the inner circle of the oil deflector 5 and the outer circle of the plunger sleeve 2, and the gap oil storage chamber 53 is matched in a limited layout space. The increase of the gap oil storage chamber 53 will increase the volume of the oil storage chamber, and play a better buffering and decompression effect on the high-pressure fuel that rushes out of the fuel chamber 111 during the oil leakage stage of the pump oil system. The end 51 is designed as a concave closing structure, and the pressure loss along the high-pressure fuel flowing through the slit will be significantly increased, and the high-pressure fuel flow rate flowing out through the upper and lower end surfaces of the oil retaining ring 5 will be reduced, and the impact force on the wall of the pump body 1 at the corresponding position will be greatly reduced. This structure can reduce the impact force of high-pressure fuel on the oil retaining ring 5, the retaining spring 4 and the pump body 1, and significantly improve the reliability and service life of the oil retaining ring 5, the retaining spring 4 and the pump body 1.

[0054] For further information, see Figure 6 The plunger sleeve 2 is provided with a plunger sleeve oil return hole 24 communicating with the oil return hole 52, and the oil return hole 52 is located below the plunger sleeve oil return hole 24. Specifically, the relative deviation distance between the upper edge of the oil return hole 52 and the lower edge of the plunger sleeve oil return hole 24 is L1, and the relative deviation distance between the upper end plane position of the oil retaining ring 5 and the upper edge of the plunger sleeve oil return hole 24 is L2. Preferably, the value of L1 is 1.5-2.5 mm, and the value of L2 is 2-4 mm. By controlling L1 and L2, the high-pressure fuel that rushes out of the oil inlet and return hole 52 to the fuel chamber 111 during the oil leakage stage of the pump oil system can first impact the inner wall of the oil retaining ring 52, and then flow out through the oil inlet and return hole 52 after impact rebound. The impact force of the high-pressure fuel is greatly reduced after multiple rebounds on the inner wall of the oil retaining ring 5, and the fuel pressure passing through the oil inlet and return hole 52 is reduced, which effectively reduces the impact cavitation of the wall of the pump body 1 caused by the high-pressure fuel, and also effectively reduces the impact pressure of the high-pressure fuel on the sealing ring 3, thereby extending the service life of the plunger sleeve 2.

[0055] Compared with the prior art, in the plunger sleeve 2 of the present invention, the multi-stage sealing ring 3, the pressure relief ring belt 12, the oil baffle ring 5 structure and the snap ring 4 are used, effectively prolonging the service life of the pump body 1 and the plunger sleeve 2. If only the multi-stage sealing ring 3 is added, the corrosion between the plunger sleeve 2 and the pump body 1 can be slowed down. The service life improvement rate of the plunger sleeve 2 is 200%, and the service life improvement rate of the pump body 1 is 50%. By adopting the multi-stage sealing ring 3 and setting the pressure relief ring belt 12, the service life improvement rate of the plunger sleeve is 650%. By adopting the multi-stage sealing ring 3, setting the pressure relief ring belt 12 and the flat oil baffle ring 5 (spring), the corrosion between the plunger sleeve 2 and the pump body 1, the damage of the sealing ring and the cavitation of the pump body can be slowed down. The service life improvement rate of the plunger sleeve 2 is 800%, and the service life improvement rate of the pump body 1 is 200%. Therefore, the overall effect of the multi-stage sealing ring 3, setting the pressure relief ring belt 12 and the flat oil baffle ring 5 (spring) is much better than the single or double-item solutions of setting the multi-stage sealing ring 3, the pressure relief ring belt 12 and the flat oil baffle ring 5 (spring), effectively improving the service life of the plunger sleeve 2 and the pump body 1.

[0056] Comparison Table of Product Service Life between the Design Scheme of the Present Invention and the Prior Art Scheme

[0057]

[0058] Please refer to Figure 1 、 Figure 8 and Figure 9 , a pump oil system assembly of an oil supply pump, including a plunger sleeve structure with a multi-stage sealing ring of the oil supply pump, a plunger 6 installed in the plunger sleeve 2 and an oil outlet valve assembly 9. Specifically, the plunger sleeve 2 is provided with a through second installation cavity 25, and the oil outlet valve assembly 9 and the plunger 6 are installed in the second installation cavity 25. The plunger sleeve 2 and the plunger 6 form a plunger pair.

[0059] Further, please refer to Figure 8 and Figure 9, the fuel injection valve assembly 9 includes a fuel injection valve seat assembly 7 and a fuel injection valve core assembly 8. The fuel injection valve core assembly 8 includes a fuel injection valve core body 81, a valve seat 82, a spring 83, a spring seat 84, and a steel ball 85. The fuel injection valve core body 81 is press-fitted with the valve seat 82, and a third installation cavity 86 is formed therebetween. The spring 83, the spring seat 84, and the steel ball 85 are installed in the third installation cavity 86. One end of the spring 83 abuts against the spring seat 84, and the other end abuts against the valve seat 82. The fuel injection valve seat assembly 7 is provided with a fuel passage 76, and the steel ball 85 is used to open or close the connection between the third installation cavity 86 and the fuel passage 76. Specifically, the fuel passage 76 is connected to a mechanical fuel injector via an external high-pressure fuel pipe. The valve seat 82 is provided with a through hole 821 near the fuel passage 76, so that the fuel pressure P2 in the fuel passage 76 acts on the steel ball 85. The valve seat 82 is provided with a conical cavity 822 that cooperates with the steel ball 85. The conical cavity 822 is connected to the through hole. The fuel pressure P2 fluctuation is transmitted to the steel ball 85 through the through hole 821. The spring seat 84 is provided with an arc-shaped groove 841 that cooperates with the steel ball 85. The steel ball 85 is arranged between the conical cavity 822 and the arc-shaped groove 841. With the conical cavity 822 and the arc-shaped groove 841, the centering fit of the steel ball 85 is good, and it can ensure that the steel ball 85 does not deviate greatly from the center line of the valve seat 82 during the opening and closing process of the steel ball 85, ensuring the sealing performance between the steel ball 85 and the valve seat 82. During use, when the mechanical fuel injector stops injecting, if the high-pressure fuel in the high-pressure fuel pipe generates a pressure fluctuation, causing the fuel pressure P2 in the fuel passage 76 to rise abnormally and be higher than the sum of the internal high-pressure fuel pressure P1 of the fuel pumping system and the spring force F1 of the spring 83, under the action of the pressure difference, the fuel pressure P2 compresses the spring 83, and the steel ball 85 moves downward to open the connection between the third installation cavity 86 and the fuel passage 76. The fuel in the fuel passage 76 is discharged to the inside of the fuel pumping system through this place, eliminating the pressure fluctuation in the high-pressure fuel pipe. When the fuel pressure P2 in the fuel passage 76 is lower than the sum of the internal high-pressure fuel pressure P1 of the fuel pumping system and the spring force F1 of the spring 83, the steel ball 85 resets and seals, closing the connection between the third installation cavity 86 and the high-pressure oil passage, cutting off the continuous leakage of fuel in the high-pressure fuel pipe, maintaining the pressure in the high-pressure fuel pipe, and ensuring that the working pressure of the mechanical fuel injector is within the set range. Therefore, the fuel injection valve assembly 9 has the dual functions of high-pressure sealing and balancing the pressure fluctuation in the high-pressure fuel pipe, ensuring the normal function and reliability of the fuel pumping system, the high-pressure fuel pipe, and the mechanical fuel injector; preventing abnormal injection of the mechanical fuel injector and ensuring the engine performance.

[0060] Further, the fuel outlet valve seat assembly 7 includes a fuel outlet valve holder 71, a fuel outlet valve spring seat 72, an adjusting shim 73, a fuel outlet valve spring 74, and a fuel outlet valve seat 75. Threads are provided at both ends of the fuel outlet valve holder 71. The fuel outlet valve holder 71 and the fuel outlet valve seat 75 are provided with a coaxial through fourth installation cavity 711. The fuel outlet valve spring seat 72, the adjusting shim 73, the fuel outlet valve spring 74, and the fuel outlet valve core assembly 8 are sequentially installed in the fourth installation cavity 711. One end of the fuel outlet valve spring 74 abuts against the adjusting shim 73, and the other end abuts against the fuel outlet valve core assembly 8. Specifically, the fuel outlet valve holder 71 is connected to the external high-pressure fuel pipe through threads, and the fuel outlet valve holder 71 is locked and installed with the internal thread of the plunger sleeve 2 through threads. The upper end of the fuel outlet valve core body 81 and the fuel outlet valve seat 75 are respectively provided with conical surfaces that are matched for sealing, and the high-pressure fuel is sealed by the conical surfaces. The middle and lower parts of the fuel outlet valve seat 75 and the fuel outlet valve core body 81 adopt a cylindrical slide valve type, and evenly distributed oil passage 811 is provided in the cylindrical mating section of the fuel outlet valve core body 81. The fuel outlet valve spring 74 is used to seal or communicate with the fuel passage 76. By selecting adjusting shims 73 with different thicknesses, the opening pressure of the fuel outlet valve assembly 9 can be adjusted, improving the applicability of the fuel valve assembly.

[0061] Further, please refer to Figure 10 , vertical, inclined and horizontal oil drain grooves 61 and an inclined oil control bevel 62 are provided on the upper part of the plunger 6. The pump body 1 is provided with a fuel inlet passage 16, a main fuel return passage 17, and a fuel leakage return passage 18. The fuel inlet passage 16 and the main fuel return passage 17 are communicated through the fuel cavity 111, and the fuel leakage return passage 18 is communicated with the return fuel tank through the main fuel return passage 17. Specifically, the fuel is transported to the fuel cavity 111 through the fuel inlet passage 16. After the fuel cavity 111 is filled with fuel, the excess fuel will flow back to the return fuel tank through the main fuel return passage 17. At the same time, the main fuel return passage 17 is responsible for transporting the fuel returned by the fuel leakage return passage 18 of the fuel pumping system back to the return fuel tank, avoiding the pressure increase caused by the blocked flow of the fuel in the fuel cavity 111, dynamically maintaining the fuel pressure in the fuel cavity 111 within a limited pressure fluctuation range, and preventing the sealing function of the sealing ring 3 from failing due to excessive pressure.

[0062] The working principle of the fuel pumping system of the present invention is as follows:

[0063] During operation, the plunger 6 slides in the second installation cavity 25. A variable-volume oil-pressing chamber 26 is formed by the inner wall of the second installation cavity, the upper end face of the plunger 6, and the conical surfaces that are respectively provided on the upper end of the oil outlet valve spool body 81 and the oil outlet valve seat 75 for mating and sealing. As the volume of the oil-pressing chamber 26 decreases, the fuel is compressed, and the fuel pressure P3 in the plunger sleeve rises rapidly. When the fuel pressure P3 in the plunger sleeve rises high enough to overcome the opening pressure of the oil outlet valve assembly 9 (the elastic force F2 of the oil outlet valve spring 74 and part of the weight of the oil outlet valve assembly 9), the oil outlet valve spool body 81 lifts to expose the oil passage 811, and the fuel in the oil-pressing chamber 26 flows out of the fuel pump system along the oil passage 811 and is transported to the injector through the external high-pressure oil pipe. The working process of the fuel pump system can be divided into the following three stages:

[0064] I. Suction stage

[0065] Please refer to Figure 11 . During the suction stage, the oil outlet valve spool body 81 is in a compressed and sealed state with the oil outlet valve seat 75 under the pre-tightening pressure of the oil outlet valve spring 74. During the downward sliding of the plunger 6, the volume of the oil-pressing chamber 26 increases, the pressure in the oil-pressing chamber 26 decreases, and the fuel pressure is lower than that in the fuel chamber 111. When the plunger 6 continues to move downward until its top plane exposes the oil inlet and return hole 24 on the plunger sleeve 2, the fuel in the fuel chamber 111 flows through the oil inlet and return hole 52 and is quickly sucked into the oil-pressing chamber 26 through the oil inlet and return hole 24 on the plunger sleeve 2 under the action of the pressure difference.

[0066] II. Oil-pressing stage

[0067] Please refer to Figure 10 and Figure 12 . During the oil-pressing stage, at the beginning, the oil outlet valve spool body 81 is still in a sealed state with the oil outlet valve seat 75 under the pre-tightening pressure of the oil outlet valve spring 74. As the plunger 6 continues to move upward, from the moment the upper top plane of the plunger 6 covers the upper edge of the oil inlet and return hole 24 on the plunger sleeve to the moment when the control bevel 62 of the plunger 6 is not connected to the lower edge of the oil inlet and return hole 24 on the plunger sleeve, this upward movement of the plunger 6 is called the effective oil-pressing stroke P. During the effective oil-pressing stroke P, the volume of the oil-pressing chamber 26 decreases, and the fuel is compressed and the pressure rises rapidly. When the fuel pressure P3 in the oil-pressing chamber 26 of the plunger sleeve rises high enough to overcome the opening pressure of the oil outlet valve assembly 9 and the external fuel pressure acting on the oil outlet valve spool 81, the oil outlet valve spool body 81 lifts, and the fuel passes through the circumferential oil passage 811 designed on the oil outlet valve spool body 81 and is sent out of the fuel pump system through the fuel passage 76.

[0068] III. Oil-draining stage

[0069] Please refer to Figure 13, The fuel drainage stage is the end of the fuel pressure stage. As the high-pressure fuel in the fuel pressure chamber 26 continuously flows out of the fuel pump system, when the plunger 6 continues to move upward to a certain position, the fuel control bevel 62 on the plunger 6 is connected to the fuel inlet and return hole 24 of the plunger sleeve. The high-pressure fuel in the fuel pressure chamber 26 will pass through the drain groove 61 on the plunger 6 and then be connected through the fuel inlet and return hole 24 of the plunger sleeve to form a pressure relief channel. The high-pressure fuel rushes out of the fuel inlet and return hole 24 of the plunger sleeve at high speed to the inner wall surface of the oil retaining ring 5, and then after rebounding, it is decompressed once in the gap oil storage chamber 53 formed between the oil retaining ring 5 and the plunger sleeve. The high-pressure fuel in the gap oil storage chamber 53 mainly flows out to the fuel chamber 111 through the fuel inlet and return hole 52 on the oil retaining ring 5, and secondly, a small amount of high-pressure fuel will flow out to the fuel chamber 111 through the installation gap between the upper end plane of the oil retaining ring 5 and the plunger sleeve 2. During this process, the pressure of the high-pressure fuel in the fuel pressure chamber 26 rapidly decreases and is not sufficient to overcome the opening pressure of the fuel outlet valve assembly 9 and the external fuel pressure acting on the fuel outlet valve core. The fuel outlet valve core body 81 falls back, and the fuel outlet valve core body 81 and the fuel outlet valve seat 75 return to the sealed state. After the plunger 6 continues to move upward to the top dead center, it starts to move downward under the restoring force of the fuel pump system spring, and the fuel pump system turns into the oil suction stage again, forming an oil supply cycle.

[0070] For the plunger sleeve structure and fuel pump system assembly of the multi-stage sealing ring of the fuel pump of the present invention, by setting the multi-stage sealing ring 3 and the pressure reducing ring belt 12, it effectively prevents impurities and corrosive or humid gases in the external environment from entering the sealing ring 3 near the pressure reducing ring belt 12, reduces the impact of the fuel pressure in the fuel chamber 111 on the sealing ring 3 near the pressure reducing ring belt 12, reduces the frequency of damage and abnormal deformation of the sealing ring 3 near the pressure reducing ring belt 12, and improves its sealing reliability. The upper and lower end faces of the oil retaining ring 5 are flat, and the two ends 51 are arc concave closing structures, which reduce the impact force of the high-pressure fuel on the oil retaining ring 5, the snap ring 4 and the pump body 1, and improve its reliability and service life. The snap ring 4 arranged on the inclined surface not only improves the working reliability and fatigue life of the snap ring 4, but also buffers the impact force on the oil retaining ring 5 through the acting force of the snap ring 4, dynamically compensates for the machining deviation of the length dimension of the oil retaining ring 5 or the wear amount generated after the parts are used, and improves its assembly and use stability. The fuel inlet and return hole 24 of the plunger sleeve connected to the fuel inlet and return hole 52 cooperates to avoid cavitation erosion of the wall surface of the pump body 1 caused by the high-pressure fuel. The fuel outlet valve core assembly 8 is set to ensure that the working pressure of the mechanical injector is within the set range.

[0071] The above specific implementation manners further elaborate on the purpose, technical solution and beneficial effects of the present invention. It should be understood that the above is only the specific implementation method of the present invention and is not used to limit the present invention. Any modifications, equivalent replacements and improvements made within the gist of the present invention should be included in the protection scope of the present invention.

Claims

1. The plunger sleeve structure of a multi-stage sealing ring for an oil supply pump, characterized in that, It includes a pump body (1) provided with a fuel chamber (111) and a plunger sleeve (2) sleeved on the fuel chamber (111); at least two annular grooves (21) are arranged at intervals on the outer side of the plunger sleeve (2), and a sealing ring (3) is installed in each annular groove (21); the lower edge position of the annular groove (21) close to the fuel chamber (111) and the inner wall of the fuel chamber (111) form a decompression ring belt (12) for reducing the oil pressure.

2. The plunger sleeve structure of the multi-stage sealing ring of the fuel supply pump according to claim 1, characterized in that, The decompression ring belt (12) includes a buffer area (121), a decompression area (122) and a flow reduction area (123) arranged in sequence from the sealing ring (3) to the fuel chamber (111); the length of the decompression area (122) is h, the width is t, the value of h is not less than 1.2 mm, and the value of t is 0.05 - 0.1 mm.

3. The plunger sleeve structure of the multi-stage sealing ring of the fuel supply pump according to claim 1 or 2, characterized in that, The cross-section of the sealing ring (3) close to the fuel chamber (111) is elliptical, and the remaining sealing rings (3) are one of elliptical, circular or frustum-shaped.

4. The plunger sleeve structure of the multi-stage sealing ring of the fuel supply pump according to claim 1 or 2, characterized in that, It further includes a circlip (4) and an oil baffle ring (5). A circlip groove (23) is also provided on the outer side of the plunger sleeve (2). The circlip (4) is installed in the circlip groove (23). The plunger sleeve (2) is provided with a step surface (22). The oil baffle ring (5) is arranged on the outer side of the plunger sleeve (2), and one end of the oil baffle ring (5) abuts against the step surface (22), and the other end abuts against one end of the circlip (4).

5. The plunger sleeve structure of the multi-stage sealing ring of the fuel supply pump according to claim 4, characterized in that, The circlip groove (23) is an inclined surface and is arc-transitioned with the end face close to the oil baffle ring (5).

6. The plunger sleeve structure of the multi-stage sealing ring of the fuel supply pump according to claim 4, characterized in that, The upper and lower end faces of the oil baffle ring (5) are flat. The oil baffle ring (5) is provided with a head (51), and the head (51) is a closed structure with an inward concave arc. The oil baffle ring (5) is evenly provided with a number of oil inlet and return holes (52) at intervals along its circumference.

7. The plunger sleeve structure of the multi-stage sealing ring of the fuel supply pump according to claim 6, characterized in that, The plunger sleeve (2) is provided with a plunger sleeve oil inlet and return hole (24) communicated with the oil inlet and return holes (52), and the oil inlet and return holes (52) are located below the plunger sleeve oil inlet and return hole (24).

8. An oil pumping system assembly includes the plunger sleeve structure of the multi-stage sealing rings of the fuel supply pump according to any one of claims 1 - 7, and further includes a plunger (6) and an outlet valve assembly (9) installed in the plunger sleeve (2).

9. The fuel pump assembly according to claim 8, wherein The outlet valve assembly (9) includes an outlet valve seat assembly (7) and an outlet valve core assembly (8). The outlet valve core assembly (8) includes an outlet valve core body (81), a valve seat (82), a spring (83), a spring seat (84), and a steel ball (85); the outlet valve core body (81) and the valve seat (82) are interference-fitted, and a third installation cavity (86) is formed between them. The spring (83), the spring seat (84), and the steel ball (85) are installed in the third installation cavity (86). One end of the spring (83) abuts against the spring seat (84), and the other end abuts against the valve seat (82). The outlet valve seat assembly (7) is provided with a fuel passage (76), and the steel ball (85) is used to open or close the communication between the third installation cavity (86) and the fuel passage (76).

10. The fuel pump assembly according to claim 9, characterized in that, The fuel injection valve seat assembly 7 includes a fuel injection valve holder 71, a fuel injection valve spring seat 72, an adjusting shim 73, a fuel injection valve spring 74, and a fuel injection valve seat 75; both ends of the fuel injection valve holder 71 are provided with threads, and the fuel injection valve holder 71 and the fuel injection valve seat 75 are provided with a coaxial through fourth installation cavity 711. The fuel injection valve spring seat 72, the adjusting shim 73, the fuel injection valve spring 74, and the fuel injection valve core assembly 8 are sequentially installed in the fourth installation cavity 711. One end of the fuel injection valve spring 74 abuts against the adjusting shim 73, and the other end abuts against the fuel injection valve core assembly 8.

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