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

Abstract

The utility model 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 plurality of sealing rings and the pressure reducing ring belts, so that the sealing rings close to a fuel oil cavity are suitable for a 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 utility model further discloses an oil pumping system assembly.

Description

Technical Field

[0001] This utility model belongs to the technical field of mechanical pump oil system, specifically relating to a plunger sleeve structure with multi-stage sealing rings for an oil supply pump and an oil pump system assembly. Background Technology

[0002] As one of the fuel pumps in the heart of the engine, the mechanical fuel pump is commonly used in high-pressure, high-flow fuel pump circuit systems.

[0003] Most existing mechanical fuel pumps adopt a suspended plunger sleeve layout, such as Figure 2 As 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 from the mechanical fuel pump and to prevent impurities and gases from entering the external environment, thereby improving engine safety. However, mechanical fuel pumps are mainly used in harsh environments and complex climatic conditions such as marine propulsion, mining machinery, and cargo transportation. After long-term use, the following problems arise:

[0004] 1. For dust and water protection, the sealing ring 3 of the plunger sleeve 2 is installed at a distance from the end face of the pump body 1. This design can delay the time of damage by impurities or corrosive gases to some extent. However, this results in a large volume of impurities and corrosive gases deposited in the first area 13, which is not conducive to maintaining the sealing function of the sealing ring 3. Specifically, particulate impurities, corrosive gases, and water vapor in the external environment enter the sealing ring 3 through the gap between the plunger sleeve and the pump body. The particulate impurities will rub against or adhere to the sealing ring 3, causing oil leakage after the sealing ring 3 is damaged. Secondly, the corrosive gases or water vapor deposited at the sealing ring 3 cannot be effectively removed, and an electrochemical reaction occurs, corroding the surface of the plunger sleeve 2 and the pump body 1. Over time, this will lead to the sealing failure of the sealing ring 3 and oil leakage.

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

[0006] The purpose of this invention is to provide a plunger sleeve structure with multi-stage sealing rings for an oil pump. By strengthening the sealing function of the plunger sleeve sealing rings, the reliability of the plunger sleeve and pump body in complex environments is improved, and their service life is effectively extended.

[0007] The purpose of this utility model is achieved through such a technical solution, specifically providing a plunger sleeve structure for a multi-stage sealing ring of a fuel pump, including: a pump body with a fuel chamber and a plunger sleeve fitted on the fuel chamber; at least two annular grooves are provided at intervals on the outer side of the plunger sleeve, and a sealing ring is installed in each annular groove; the lower edge of the annular groove near the fuel chamber forms a pressure-reducing ring with the inner wall of the fuel chamber to reduce oil pressure.

[0008] Multi-stage sealing rings are installed on the outside of the plunger sleeve to reduce the impact of external particulate impurities, corrosive gases, and water vapor on the sealing rings near the fuel chamber, ensuring the normal function of the sealing rings near the fuel chamber and improving sealing efficiency. A pressure-reducing ring is installed to form a slit effect, which reduces the pressure impact of high-pressure oil in the fuel chamber on the sealing rings near the fuel chamber, reduces the frequency of damage and abnormal deformation of the sealing rings near the fuel chamber, and improves their reliability.

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

[0010] Preferably, the sealing ring near the fuel chamber has an elliptical cross-section, while the remaining sealing rings are one of an elliptical, circular, or frustum-shaped shape.

[0011] Preferably, it also includes a retaining ring and an oil baffle ring. The outer side of the plunger sleeve is provided with a retaining ring groove, the retaining ring is installed in the retaining ring groove, the plunger sleeve is provided with a stepped surface, the oil baffle ring is provided on the outer side of the plunger sleeve, and one end of the oil baffle ring abuts against the stepped surface, and the other end abuts against one end of the retaining ring.

[0012] Preferably, the retaining ring groove is an inclined surface and transitions to the end face near the oil baffle ring with an arc.

[0013] Preferably, the upper and lower end faces of the oil baffle are flat, the oil baffle has an end with a concave arc-shaped opening, and the oil baffle has a number of oil inlet and outlet holes evenly spaced along its circumference.

[0014] Preferably, the plunger sleeve is provided with a plunger sleeve inlet and return oil hole that communicates with the inlet and return oil hole, and the inlet and return oil hole is located below the plunger sleeve inlet and return oil hole.

[0015] Due to the adoption of the above technical solution, this utility model has the following beneficial effects:

[0016] Multiple sealing rings and pressure-reducing rings are installed on the plunger sleeve, making the sealing rings near the fuel chamber suitable for complex environments. The pressure impact of high-pressure oil in the fuel chamber on the sealing rings is reduced, decreasing the frequency of damage and abnormal deformation, and improving the reliability of the sealing rings.

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

[0018] Another objective of this utility model is achieved through such a technical solution, specifically providing an oil supply pump system assembly, including a plunger sleeve structure with multi-stage sealing rings for the oil supply pump and a plunger and oil outlet valve assembly installed in the plunger sleeve.

[0019] Preferably, the delivery valve assembly includes a delivery valve seat assembly and a delivery valve core assembly. The delivery valve core assembly includes a delivery valve core body, a valve seat, a spring, a spring seat, and a steel ball. The delivery valve core body and the valve seat are interference-fitted together, forming a third mounting cavity. The spring, spring seat, and steel ball are mounted in the third mounting cavity. One end of the spring abuts against the spring seat, and the other end abuts against the valve seat. The delivery valve seat assembly is provided with a fuel passage, and the steel ball is used to open or close the connection between the third mounting cavity and the fuel passage.

[0020] Preferably, the oil outlet valve seat assembly includes an oil outlet valve seat, an oil outlet valve spring seat, an adjusting shim, an oil outlet valve spring, and an oil outlet valve seat; the oil outlet valve seat has threads at both ends, and the oil outlet valve seat and the oil outlet valve seat have a coaxial through fourth mounting cavity; the oil outlet valve spring seat, the adjusting shim, the oil outlet valve spring, and the oil outlet valve core assembly are sequentially installed in the fourth mounting cavity; one end of the oil outlet valve spring abuts against the adjusting shim, and the other end abuts against the oil outlet valve core assembly.

[0021] Due to the adoption of the above technical solution, the beneficial effects of this utility model are as follows:

[0022] By setting up multi-stage sealing rings, the pump oil system assembly can be used for a long time in complex environments, improving the reliability of its sealing rings and extending its service life. The oil outlet valve core assembly ensures that the working pressure of the mechanical injector is within the set range. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of this utility model, the accompanying drawings used in the specific embodiments will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0024] Figure 1 This is a schematic diagram of the plunger sleeve structure of a multi-stage sealing ring for an oil supply pump and the structure of the oil pump system assembly according to this utility model.

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

[0026] Figure 3 A schematic diagram of the plunger sleeve structure for a multi-stage sealing ring oil supply pump;

[0027] Figure 4This is an enlarged schematic diagram of the pressure-reducing ring belt;

[0028] Figure 5 This is a schematic diagram showing the difference in outer diameter between two levels.

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

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

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

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

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

[0034] Figure 11 This is a schematic diagram of the oil absorption stage;

[0035] Figure 12 This is a schematic diagram of the oil pressing stage;

[0036] Figure 13 This is a schematic diagram of the oil draining stage.

[0037] Figure label:

[0038] 1-Pump body, 11-First mounting cavity, 111-Fuel cavity, 12-Pressure relief ring, 121-Buffer area, 122-Pressure relief area, 123-Decrease area, 13-First space area, 14-Second space area, 15-Phase adjustment shim, 16-Fuel inlet passage, 17-Main fuel return passage, 18-Fuel leakage return passage;

[0039] 2-Plunger sleeve, 21-Annular groove, 22-Stepped surface, 23-Snap ring groove, 24-Plunger sleeve inlet and outlet oil holes, 25-Second mounting cavity; 26-Oil pressure chamber;

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

[0041] 4-Snap ring;

[0042] 5-Oil retainer ring, 51-End, 52-Oil inlet / outlet hole, 53-Clearance oil reservoir chamber;

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

[0044] 7-Outlet valve seat assembly, 71-Fuel valve seat, 711-Fourth mounting cavity, 72-Outlet valve spring seat, 73-Adjusting shim, 74-Outlet valve spring, 75-Outlet valve seat, 76-Fuel passage;

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

[0046] 9- Oil outlet valve assembly. Detailed Implementation

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

[0048] Please see Figure 1 and Figure 3A plunger sleeve structure with multi-stage sealing rings for an oil pump includes: a pump body 1 having a fuel chamber 111 and a plunger sleeve 2 fitted onto the fuel chamber 111; the outer side of the plunger sleeve 2 is provided with at least two annular grooves 21 spaced apart, each annular groove 21 being fitted with a sealing ring 3; the lower edge of the annular grooves 21 near the fuel chamber 111 forms a pressure-reducing ring 12 with the inner wall of the fuel chamber 111 to reduce oil pressure. Specifically, the pump body 1 is provided with a first mounting cavity 11 for suspending and mounting the plunger sleeve 2, and the fuel chamber 111 is disposed in the first mounting cavity 11. At least two parallel annular grooves 21 are spaced apart along the axial direction of the plunger sleeve 2, each annular groove 21 being fitted with a sealing ring 3. Preferably, the sealing ring 3 is made of fluorosilicone rubber, and there are two annular grooves 21, respectively fitted with a first sealing ring 31 and a second sealing ring 32. A phase adjustment shim 15 is provided between the end face of the plunger sleeve 2 and the pump body 1. After installation, a first space region 13 is formed between the plunger sleeve 2, the phase adjustment shim 15, the pump body 1, and the first sealing ring 31, and a second space region 14 is formed between the first sealing ring 31, the plunger sleeve 2, the pump body 1, and the second sealing ring 32. In harsh operating environments and complex climatic conditions, external particulate impurities, corrosive gases, and water vapor enter the first space region 13 through the gap between the plunger sleeve 2 and the pump body 1 and deposit there. Because the plunger sleeve 2 is installed in the first mounting cavity 11, the first sealing ring 31 deforms and fills the annular groove 21. The first sealing ring 31 is closer to the end face of the pump body 1 than in the prior art, which reduces the volume of impurities and corrosive gases deposited to a certain extent, improves the sealing efficiency of the first sealing ring 31, and effectively blocks the channel for particulate impurities, corrosive gases, and water vapor to continue to invade the second space region 14, thereby ensuring that the second space region 14 is in a relatively closed environment. The second space region 14 is free from the intrusion of corrosive gases or water vapor, and no electrochemical reactions occur in this region, ensuring that the plunger sleeve 2 and pump body 1 do not corrode. Simultaneously, the relatively enclosed environment also ensures that the second sealing ring 32 does not suffer material deterioration or contamination, thus guaranteeing the normal function of the second sealing ring 32 and improving sealing efficiency. A pressure-reducing ring 12 is formed between the second sealing ring 32, the plunger sleeve 2, and the pump body 1. The pressure-reducing ring 12 is an annular slit, preventing the high fuel pressure in the fuel chamber 111 from directly impacting the second sealing ring 32. When fuel in the fuel chamber 111 passes through the pressure-reducing ring 12, the gap between the pressure-reducing ring 12 and the pump body 1 is significantly reduced, creating a slit effect. The fuel flow velocity increases as it passes through the pressure-reducing ring 12, but the pressure decreases. This weakens the pressure impact of the high-pressure oil on the second sealing ring 32, reducing the frequency of damage and abnormal deformation of the second sealing ring 32 and improving its reliability.

[0049] Further, please refer to Figures 3 to 5The pressure-reducing ring 12 includes a buffer region 121, a pressure-reducing region 122, and a reduction region 123 arranged sequentially from the sealing ring 3 to the fuel chamber 111. The length of the pressure-reducing region 122 is h, and the width is t, where h is not less than 1.2 mm and t is 0.05 to 0.1 mm. Specifically, the outer diameter of the upper edge of the annular groove 21 near the fuel chamber 111 is designed to be consistent with the outer diameter of the other annular grooves 21, and its diameter is φA; the outer diameter of the lower edge of the annular groove 21 near the fuel chamber 111 is different from the outer diameter of the other annular grooves 21, and its outer diameter is φB. The diameter difference formed by the two outer diameters is Δa (Δa = ΦB - ΦA), and the length from the lower edge of the annular groove 21 near the fuel chamber 111 to the fuel chamber 111 is h. After the plunger sleeve 2 is installed with the pump body 1, the fit clearance formed between the outer circle of the annular groove 21 near the lower edge of the fuel chamber 111 and the first mounting cavity 11 (with an inner diameter of φC) is t (t=ΦC-φB). Therefore, a ring-shaped area with a length of h and a width of t is formed between the plunger sleeve 2 and the pump body 1, which is the pressure reduction area 122. From the lower end of the pressure reduction area to the fuel chamber 111, the diameter of the plunger sleeve 2 gradually decreases, forming the reduction area 123; from the upper end of the pressure reduction area to the inner wall of the annular groove 21, the diameter of the plunger sleeve 2 gradually decreases and transitions in an arc shape, forming the buffer area 121. A two-stage outer circular structure with a diameter difference of Δa is designed on the plunger sleeve 2, which forms an annular pressure reduction ring 12 after installation and fit with the pump body 1. The purpose is to allow the plunger sleeve 2 and the pump body 1 to form an annular pressure reduction area 122 with a length of h and a width of t after assembly. The pressure reduction area 122 is an annular slit. The pressure reduction zone 122 significantly reduces the impact pressure of fuel entering the pressure reduction ring 12 from the fuel chamber 111, reducing the impact force of the fuel on the sealing ring 3 near the fuel chamber 111 and ensuring that the sealing ring 3 does not break or deform abnormally. The cross-section of the reduction zone 123 is frustum-shaped, allowing limited fuel to reach the pressure reduction zone 122 through the reduction zone 123. At the same time, the fuel is weakened by the action of the frustum-shaped outer wall of the plunger sleeve 2. The fuel reaches the buffer zone 121 through the pressure reduction zone 122. After the sealing ring 3 is installed in the annular groove 21, the buffer zone 121 is formed in the limited space, increasing the volume of the annular groove 21 towards the pressure reduction zone 122, thus buffering and reducing the pressure of the entering fuel. Preferably, the value of Δa 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, but the machining cost is also high; if the value of t is greater than 0.1 mm, the slit effect is poor. When h is less than 1.2 mm, the fuel enters the buffer zone 121 through the decompression zone 122 before it is depressurized, resulting in a poor slit effect.

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

[0051] Further, please refer to Figure 1 and Figure 6 It also includes a retaining ring 4 and an oil baffle ring 5. The outer side of the plunger sleeve 2 is provided with a retaining ring groove 23, in which the retaining ring 4 is installed. The plunger sleeve 2 has a stepped surface 22. The oil baffle ring 5 is located on the outer side of the plunger sleeve 2, with one end of the oil baffle ring 5 abutting against the stepped surface 22 and the other end abutting against one end of the retaining ring 4. Specifically, the lower edge of the reduction area 123 is horizontal to the stepped surface 22. The oil baffle ring 5 is located in the fuel chamber 111. One end of the retaining ring 4 abuts against the end face of the oil baffle ring 5, and the other end of the retaining ring 4 abuts against the inner wall of the retaining ring groove 23. The retaining ring 4 generates a continuous preload on the oil baffle ring 5, which is installed between the stepped surface 22 and the retaining ring 4.

[0052] Furthermore, the retaining ring groove 23 is an inclined surface, and it transitions with the end face near the oil baffle ring 5 by an arc. This structure ensures that the retaining ring 4, after installation, experiences an upward component force along the slope of the inclined surface, keeping it constantly within the retaining ring groove 23 and exerting continuous pressure on the oil baffle ring 5. This dynamically compensates for machining deviations in the length of the oil baffle ring 5 or wear caused by use, ensuring that the upper surface of the oil baffle ring 5 remains firmly in contact with the stepped surface 22, thus guaranteeing the assembly and stability of the oil baffle ring 5. During use, the high-pressure fuel ejected during the draining phase directly impacts the oil baffle ring 5, causing axial and radial displacement. The axial force on the oil baffle ring 5 pushes back against the retaining ring 4, causing it to move downwards along the slope of the retaining ring groove 23. During this downward displacement, the inclined surface generates a counter-pushing force on the retaining ring 4, preventing it from falling off after impact. This counter-pushing force varies with the slope of the inclined surface, resulting in a less drastic change in the force on the retaining ring 4, thus improving its operational reliability and fatigue life. The snap ring 4 acts as a buffer to cushion the impact force on the oil baffle ring 5, ensuring the assembly and stability of the oil baffle ring 5 during use. The snap ring 4 has a circular cross-section, and the snap ring groove 23 has a rounded transition to increase the contact area. The snap ring 4 is better accommodated in the snap ring groove 23.

[0053] Further, please refer to Figure 6 and Figure 7The oil baffle ring 5 has flat upper and lower end faces and an end 51 with a concave arc-shaped opening. Several inlet and outlet oil holes 52 are evenly spaced along its circumference. Specifically, compared to existing oil baffle rings with conical end faces, the oil baffle ring 5 has flat upper and lower end faces and an end 51 at each corner. The end 51 is designed with a concave arc shape, which not only reduces the clearance between the oil baffle ring and the outer circle of the plunger sleeve 2, reducing the swaying amplitude of the oil baffle ring 5 under oil pressure impact and providing a positioning function, but also allows for a smaller space at the end 51 and a larger space in the middle. After assembly, this creates a gap oil reservoir 53 between the inner ring of the oil baffle ring 5 and the outer circle of the plunger sleeve 2. Within the limited space, the increased size of the gap oil reservoir 53 increases the reservoir volume, providing better buffering and pressure reduction for the high-pressure fuel rushing into the fuel chamber 111 during the pump oil system's draining phase. The end 51 is designed with a concave opening structure, which significantly increases the pressure loss along the flow path of high-pressure fuel through this narrow slit. This reduces the flow rate of high-pressure fuel flowing out through the upper and lower end faces of the oil baffle ring 5, and greatly reduces the impact force on the pump body 1 wall at the corresponding location. This structure can reduce the impact force of high-pressure fuel on the oil baffle ring 5, the retaining ring 4, and the pump body 1, significantly improving the reliability and service life of the oil baffle ring 5, the retaining ring 4, and the pump body 1.

[0054] Further, please refer to Figure 6 The plunger sleeve 2 is provided with a plunger sleeve inlet and return oil hole 24 communicating with the inlet and return oil hole 52, and the inlet and return oil hole 52 is located below the plunger sleeve inlet and return oil hole 24. Specifically, the relative deviation distance between the upper edge of the inlet and return oil hole 52 and the lower edge of the plunger sleeve inlet and return oil hole 24 is L1, and the relative deviation distance between the upper plane position of the oil baffle ring 5 and the upper edge of the plunger sleeve inlet and return oil hole 24 is L2. Preferably, the value of L1 is 1.5 to 2.5 mm, and the value of L2 is 2 to 4 mm. By controlling L1 and L2, the high-pressure fuel that rushes out of the fuel chamber 111 from the inlet and return oil holes 52 during the oil discharge phase of the pump system can first impact the inner wall of the oil baffle ring 52. After the impact and rebound, it flows out through the inlet and return oil holes 52. The impact force of the high-pressure fuel is greatly reduced after multiple rebounds on the inner wall of the oil baffle ring 5. The fuel pressure through the inlet and return oil holes 52 is reduced, which effectively reduces the impact cavitation erosion caused by the high-pressure fuel on the wall of the pump body 1. At the same time, it also effectively reduces the impact pressure caused by the high-pressure fuel on the sealing ring 3, and extends the service life of the plunger sleeve 2.

[0055] Compared with existing technologies, the plunger sleeve 2 of this utility model, as shown in the table below, utilizes a multi-stage sealing ring 3, a pressure-reducing ring 12, an oil-blocking ring 5, and a retaining spring 4, effectively extending the lifespan of the pump body 1 and the plunger sleeve 2. Simply adding the multi-stage sealing ring 3 can slow down corrosion between the plunger sleeve 2 and the pump body 1, increasing the lifespan of the plunger sleeve 2 by 200% and the pump body 1 by 50%. Using the multi-stage sealing ring 3 and the pressure-reducing ring 12 increases the lifespan of the plunger sleeve by 650%. Using the multi-stage sealing ring 3, the pressure-reducing ring 12, and the flat oil-blocking ring 5 (spring) can slow down corrosion between the plunger sleeve 2 and the pump body 1, reduce sealing ring damage, and prevent pump body cavitation, increasing the lifespan of the plunger sleeve 2 by 800% and the pump body 1 by 200%.

[0056] Comparison table of product lifespan between the design scheme of this utility model and existing technical solutions.

[0057]

[0058] Please see Figure 1 , Figure 8 and Figure 9 An oil pumping system assembly for an oil supply pump includes a plunger sleeve structure with multi-stage sealing rings for 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 has a through second mounting cavity 25, in which the oil outlet valve assembly 9 and the plunger 6 are installed, and the plunger sleeve 2 and the plunger 6 form a plunger pair.

[0059] Further, please refer to Figure 8 and Figure 9The delivery valve assembly 9 includes a delivery valve seat assembly 7 and a delivery valve core assembly 8. The delivery valve core assembly 8 includes a delivery valve core body 81, a valve seat 82, a spring 83, a spring seat 84, and a steel ball 85. The delivery valve core body 81 and the valve seat 82 are press-fitted together, forming a third mounting cavity 86. The spring 83, spring seat 84, and steel ball 85 are mounted in the third mounting 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 delivery valve seat assembly 7 is provided with a fuel passage 76. The steel ball 85 is used to open or close the connection between the third mounting cavity 86 and the fuel passage 76. Specifically, the fuel passage 76 is connected to a mechanical 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 of the fuel passage 76 acts on the steel ball 85. The valve seat 82 is provided with a conical cavity 822 that mates with the steel ball 85. The conical cavity 822 is connected to a through hole, and 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 mates with the steel ball 85. The steel ball 85 is positioned between the conical cavity 822 and the arc-shaped groove 841. By using the conical cavity 822 and the arc-shaped groove 841, the centering fit of the steel ball 85 is good. During the opening and closing process of the steel ball 85, it can be ensured that the steel ball 85 does not deviate significantly from the center line of the valve seat 82, thus ensuring the sealing performance between the steel ball 85 and the valve seat 82. In operation, when the mechanical fuel injector is shut off, if pressure fluctuations occur in the high-pressure fuel in the high-pressure fuel line, causing an abnormal increase in the fuel pressure P2 in the fuel passage 76, exceeding the sum of the high-pressure fuel pressure P1 inside the pump system and the spring force F1 of spring 83, the fuel pressure P2 compresses spring 83 under the pressure difference. This causes steel ball 85 to move downwards, opening the third mounting chamber 86 and connecting it to the fuel passage 76. Fuel in the fuel passage 76 is then depressurized through this point and released into the pump system, eliminating the pressure fluctuations in the high-pressure fuel line. When the fuel pressure P2 in the fuel passage 76 is lower than the sum of the high-pressure fuel pressure P1 inside the pump system and the spring force F1 of spring 83, steel ball 85 returns to its original position and seals, closing the connection between the third mounting chamber 86 and the high-pressure fuel passage, cutting off further fuel leakage from the high-pressure fuel line, maintaining the pressure in the high-pressure fuel line, and ensuring that the working pressure of the mechanical fuel injector remains within the set range. Therefore, the 9-outlet delivery valve assembly has the dual functions of high-pressure sealing and balancing pressure fluctuations in the high-pressure oil pipe, ensuring the normal and reliable function of the pump system, high-pressure oil pipe and mechanical injector; preventing abnormal injection by the mechanical injector and ensuring engine performance.

[0060] Furthermore, the oil outlet valve seat assembly 7 includes an oil outlet valve seat 71, an oil outlet valve spring seat 72, an adjusting shim 73, an oil outlet valve spring 74, and an oil outlet valve seat 75. The oil outlet valve seat 71 has threads at both ends, and the oil outlet valve seat 71 and the oil outlet valve seat 75 have a coaxial through fourth mounting cavity 711. The oil outlet valve spring seat 72, the adjusting shim 73, the oil outlet valve spring 74, and the oil outlet valve core assembly 8 are sequentially installed in the fourth mounting cavity 711. One end of the oil outlet valve spring 74 abuts against the adjusting shim 73, and the other end abuts against the oil outlet valve core assembly 8. Specifically, the delivery valve seat 71 is connected to an external high-pressure fuel line via threads, and is locked in place with the internal threads of the plunger sleeve 2 via threads. The upper ends of the delivery valve core 81 and the delivery valve seat 75 are respectively provided with matching sealing conical surfaces, which are used to seal the high-pressure fuel. The lower middle end of the delivery valve seat 75 and the delivery valve core 81 adopt a cylindrical slide valve type, and the cylindrical mating section of the delivery valve core 81 has evenly distributed fuel passages 811. The delivery valve core 81 seals or connects the fuel passage 76 using the delivery valve spring 74. By selecting adjusting shims 73 of different thicknesses, the opening pressure of the delivery valve assembly 9 can be adjusted, improving the applicability of the valve assembly.

[0061] Further, please refer to Figure 10 The upper part of the plunger 6 is provided with vertical, oblique, and horizontal oil drain grooves 61 and an oblique oil control bevel 62. 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 connected through the fuel chamber 111, and the fuel leakage return passage 18 is connected to the return tank through the main fuel return passage 17. Specifically, fuel is delivered to the fuel chamber 111 through the fuel inlet passage 16. After the fuel chamber 111 is filled with fuel, the excess fuel will flow back to the return tank through the main fuel return passage 17. At the same time, the main fuel return passage 17 is responsible for delivering the fuel returned by the fuel leakage return passage 18 of the pump system back to the return tank, so as to avoid the fuel pressure in the fuel chamber 111 from rising due to obstructed flow, dynamically maintain the fuel pressure in the fuel chamber 111 within a limited pressure fluctuation range, and prevent the sealing ring 3 from failing due to excessive pressure.

[0062] The working principle of the pump oil system of this utility model is as follows:

[0063] During operation, the plunger 6 slides in the second mounting cavity 25. A variable-volume pressure chamber 26 is formed by the inner wall of the second mounting cavity, the upper end face of the plunger 6, and the matching sealing conical surfaces of the delivery valve core 81 and the upper end of the delivery valve seat 75. As the volume of the pressure chamber 26 decreases, the fuel is compressed, and the fuel pressure P3 in the plunger sleeve rises rapidly. Once the fuel pressure P3 rises sufficiently to overcome the opening pressure of the delivery valve assembly 9 (the elastic force F2 of the delivery valve spring 74 and part of the weight of the delivery valve assembly 9), the delivery valve core 81 rises, exposing the oil passage 811. The fuel in the pressure chamber 26 flows out of the pump system through the oil passage 811 and is delivered to the injector via an external high-pressure fuel line. The working process of the pump system can be divided into the following three stages:

[0064] I. Oil Absorption Stage

[0065] Please see Figure 11 During the oil suction phase, the oil outlet valve core 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. As the plunger 6 slides downward, the volume of the oil pressure chamber 26 increases, and the pressure inside the oil pressure chamber 26 decreases, which is lower than the fuel pressure in the fuel chamber 111. After the plunger 6 continues to move downward until its top plane exposes the oil inlet and return holes 24 on the plunger sleeve 2, under the action of the pressure difference, the fuel in the fuel chamber 111 flows through the oil inlet and return holes 52 and is quickly sucked into the oil pressure chamber 26 through the oil inlet and return holes 24 on the plunger sleeve 2.

[0066] II. Oil Pressing Stage

[0067] Please see Figure 10 and Figure 12 During the oil compression phase, initially, the delivery valve core 81 remains sealed to the delivery valve seat 75 under the pre-tightening pressure of the delivery valve spring 74. The plunger 6 continues to rise until its upper top plane covers the upper edge of the plunger sleeve's inlet / outlet port 24. This upward movement of the plunger 6 until the control edge 62 of the plunger 6 is not connected to the lower edge of the plunger sleeve's inlet / outlet port 24 is called the effective oil compression stroke P. Within the effective oil compression stroke P, the volume of the oil compression chamber 26 decreases, and the fuel pressure rises rapidly after being compressed. When the fuel pressure P3 in the plunger sleeve's oil compression chamber 26 rises sufficiently to overcome the opening pressure of the delivery valve assembly 9 and the external fuel pressure acting on the delivery valve core 81, the delivery valve core 81 rises, and the fuel is delivered out of the pump system through the circumferential oil passage 811 designed on the delivery valve core 81 and the fuel passage 76.

[0068] III. Oil Drainage Stage

[0069] Please see Figure 13The oil draining stage is the final stage of the oil pressurization stage. As the high-pressure fuel in the oil pressurization chamber 26 continuously flows out of the pump system, when the plunger 6 continues to move upward to a certain position, the oil control bevel 62 on the plunger 6 connects with the oil inlet and return port 24 of the plunger sleeve. The high-pressure fuel in the oil pressurization chamber 26 will pass through the oil drain groove 61 on the plunger 6, and then connect through the oil inlet and return port 24 of the plunger sleeve to form a pressure relief channel. The high-pressure fuel rushes out at high speed from the oil inlet and return port 24 of the plunger sleeve to the inner wall of the oil baffle ring 5, and then, after rebounding, completes a pressure reduction in the gap reservoir chamber 53 formed between the oil baffle ring 5 and the plunger sleeve. The high-pressure fuel in the gap reservoir chamber 53 will mainly flow out to the fuel chamber 111 through the oil inlet and return port 52 on the oil baffle ring 5, and 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 baffle ring 5 and the plunger sleeve 2. During this process, the high-pressure fuel pressure in the pressure chamber 26 drops rapidly, insufficient to overcome the opening pressure of the delivery valve assembly 9 and the external fuel pressure acting on the delivery valve core. The delivery valve core 81 falls back, and the delivery valve core 81 and the delivery valve seat 75 return to a sealed state. After the plunger 6 continues to move upward to the top dead center, it begins to move downward under the restoring force of the pump system spring, and the pump system enters the oil suction stage again, forming an oil supply cycle.

[0070] This utility model discloses a plunger sleeve structure for a multi-stage sealing ring in an oil supply pump and an oil pump system assembly. By setting up multi-stage sealing rings 3 and pressure-reducing rings 12, it effectively prevents impurities and corrosive or humid gases from the external environment from entering the sealing rings 3 near the pressure-reducing rings 12, reducing the impact of fuel pressure in the fuel chamber 111 on the sealing rings 3 near the pressure-reducing rings 12, reducing the frequency of damage and abnormal deformation of the sealing rings 3 near the pressure-reducing rings 12, and improving their sealing reliability. The upper and lower end faces of the oil baffle ring 5 are flat, and the two ends 51 are concave arc-shaped structures, reducing the impact force of high-pressure fuel on the oil baffle ring 5, the retaining spring 4, and the pump body 1, improving their reliability and service life. The retaining spring 4, set on the inclined surface, not only improves the working reliability and fatigue life of the retaining spring 4, but also buffers the impact force on the oil baffle ring 5 through the force of the retaining spring 4, dynamically compensating for the machining deviation of the length dimension of the oil baffle ring 5 or the wear caused by the use of parts, improving its assembly and use stability. The plunger sleeve, connected to the inlet and return oil ports 24 via the inlet and return oil ports 52, prevents high-pressure fuel from causing impact cavitation on the pump body 1 wall. An outlet valve assembly 8 is provided to ensure the mechanical injector's operating pressure remains within the set range.

[0071] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific implementation method of this utility model and is not intended to limit this utility model. Any modifications, equivalent substitutions, and improvements made within the scope of the spirit of this utility model should be included within the protection scope of this utility model.

Claims

1. A plunger sleeve structure with multi-stage sealing rings for an oil supply pump, characterized in that, The pump body (1) comprises a fuel cavity (111) and a plunger sleeve (2) sleeved on the fuel cavity (111); at least two ring grooves (21) are arranged on the outer side of the plunger sleeve (2), and a sealing ring (3) is arranged in each ring groove (21); and a pressure reducing ring belt (12) for reducing oil pressure is formed between the lower edge of the ring groove (21) close to the fuel cavity (111) and the inner wall of the fuel cavity (111).

2. The plunger sleeve structure of a multi-stage sealing ring of an oil feed pump according to claim 1, wherein The pressure reducing ring belt (12) comprises a buffer area (121), a pressure reducing area (122) and a reducing amount area (123) arranged in sequence from the sealing ring (3) to the fuel cavity (111); the length of the pressure reducing area (122) is h, and the width is t, wherein h is not less than 1.2 mm, and t is 0.05-0.1 mm.

3. The plunger sleeve structure of a multi-stage sealing ring of an oil feed pump according to claim 1 or 2, characterized in that, The cross section of the sealing ring (3) close to the fuel cavity (111) is oval, and the cross sections of the other sealing rings (3) are one of oval, circular and circular truncated cone.

4. The plunger sleeve structure of a multi-stage sealing ring of an oil feed pump according to claim 1 or 2, characterized in that, The plunger sleeve (2) further comprises a snap spring (4) and an oil blocking ring (5), the outer side of the plunger sleeve (2) is further provided with a snap spring groove (23), the snap spring (4) is arranged in the snap spring groove (23), the plunger sleeve (2) is provided with a stepped surface (22), the oil blocking ring (5) is arranged on the outer side of the plunger sleeve (2), one end of the oil blocking ring (5) abuts against the stepped surface (22), and the other end of the oil blocking ring (5) abuts against one end of the snap spring (4).

5. The plunger sleeve structure of a multi-stage sealing ring of an oil feed pump according to claim 4, wherein The snap spring groove (23) is an inclined surface, and the end surface close to the oil blocking ring (5) is circularly arc-shaped.

6. The plunger sleeve structure of a multi-stage sealing ring of an oil feed pump according to claim 4, wherein The upper and lower end surfaces of the oil blocking ring (5) are flat, the oil blocking ring (5) is provided with an end head (51), the end head (51) is a circularly concave closing structure, and the oil blocking ring (5) is uniformly and interval ly provided with a plurality of oil inlet and return holes (52) along the circumferential direction.

7. The plunger sleeve structure of a multi-stage sealing ring of an oil feed pump according to claim 6, wherein The plunger sleeve (2) is provided with a plunger sleeve oil inlet and return hole (24) in communication 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. A pump oil system assembly characterized by, The plunger sleeve structure of the multi-stage sealing ring of the fuel supply pump comprises the plunger sleeve structure of the multi-stage sealing ring of the fuel supply pump according to any one of claims 1-7, and further comprises a plunger (6) and an oil outlet valve assembly (9) arranged in the plunger sleeve (2).

9. The pump oil system assembly of claim 8, wherein, The oil outlet valve assembly (9) comprises an oil outlet valve seat assembly (7) and an oil outlet valve core assembly (8), the oil outlet valve core assembly (8) comprises an oil outlet valve core body (81), a valve seat (82), a spring (83), a spring seat (84) and a steel ball (85), the oil outlet valve core body (81) and the valve seat (82) are interference-fitted, a third installation cavity (86) is formed between the oil outlet valve core body (81) and the valve seat (82), the spring (83), the spring seat (84) and the steel ball (85) are arranged in the third installation cavity (86), one end of the spring (83) abuts against the spring seat (84), the other end of the spring (83) abuts against the valve seat (82), the oil outlet valve seat assembly (7) is provided with a fuel passage (76), and the steel ball (85) is used for opening or closing the communication between the third installation cavity (86) and the fuel passage (76).

10. The pump oil system assembly of claim 9, wherein, The oil outlet valve seat assembly (7) comprises an oil outlet valve tight seat (71), an oil outlet valve spring seat (72), an adjusting gasket (73), an oil outlet valve spring (74) and an oil outlet valve seat (75); the oil outlet valve tight seat (71) is provided with threads at both ends, the oil outlet valve tight seat (71) and the oil outlet valve seat (75) are provided with coaxial through fourth installation cavities (711), the oil outlet valve spring seat (72), the adjusting gasket (73), the oil outlet valve spring (74) and the oil outlet valve core assembly (8) are sequentially installed in the fourth installation cavities (711), one end of the oil outlet valve spring (74) abuts against the adjusting gasket (73), and the other end abuts against the oil outlet valve core assembly (8).

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