阅读说明：本技术 一种高压燃油泵 (High-pressure fuel pump ) 是由 郑龙浩 王辰 于 2021-08-18 设计创作，主要内容包括：本发明公开了一种高压燃油泵,包括壳体及安装在其底部的外密封壳所述壳体的内部开设有输油室,所述输油室的顶部连接有缓冲凸钮,所述输油室的顶部开设有输油孔,所述输油室的内壁活动连接有活塞杆,所述活塞杆的底部连接有下连接架,所述活塞杆包括柱塞杆,所述柱塞杆的顶部安装有柱塞套和密封圈一,所述密封圈一卡接于柱塞套和柱塞杆之间形成的凹槽中,所述柱塞杆的顶部开设有容纳槽。本发明通过设置的缓冲凸钮减轻柱塞套靠近输油室顶部时的冲击,避免柱塞套直接撞击输油室的顶部,使柱塞套损伤,延长柱塞套的使用寿命,当燃油渗漏时,通过排杂槽能够对渗漏的液体进行引流,并且防止柱塞套和输油室中卡进杂质。(The invention discloses a high-pressure fuel pump which comprises a shell and an outer sealing shell arranged at the bottom of the shell, wherein an oil conveying chamber is arranged inside the shell, the top of the oil conveying chamber is connected with a buffering convex button, the top of the oil conveying chamber is provided with an oil conveying hole, the inner wall of the oil conveying chamber is movably connected with a piston rod, the bottom of the piston rod is connected with a lower connecting frame, the piston rod comprises a plunger rod, the top of the plunger rod is provided with a plunger sleeve and a first sealing ring, the first sealing ring is clamped in a groove formed between the plunger sleeve and the plunger rod, and the top of the plunger rod is provided with an accommodating groove. According to the invention, the impact of the plunger sleeve approaching the top of the oil delivery chamber is reduced through the arranged buffering convex button, the plunger sleeve is prevented from directly impacting the top of the oil delivery chamber, the plunger sleeve is prevented from being damaged, the service life of the plunger sleeve is prolonged, when fuel oil leaks, leaked liquid can be guided through the impurity discharging groove, and impurities in the plunger sleeve and the oil delivery chamber are prevented from being clamped.)

1. The utility model provides a high pressure fuel pump, includes casing (1) and installs outer seal shell (6) in its bottom, its characterized in that: defeated grease chamber (2) have been seted up to the inside of casing (1), the top of defeated grease chamber (2) is connected with buffering convex button (3), the oil transmission hole has been seted up at the top of defeated grease chamber (2), the inner wall swing joint of defeated grease chamber (2) has piston rod (4), the bottom of piston rod (4) is connected with down link (5), piston rod (4) include plunger rod (401), plunger sleeve (402) and sealing washer (404) are installed to the top of plunger rod (401), sealing washer (404) joint is in the recess that forms between plunger sleeve (402) and plunger rod (401), holding tank (403) have been seted up at the top of plunger rod (401), the inner wall fixedly connected with adapter sleeve (405) of holding tank (403), the top fixed mounting of adapter sleeve (405) has contact piece (406), contact piece (406), Connecting sleeve (405) and holding tank (403) form airtight cavity, and airtight cavity's internally mounted has buffer spring (407), and is a plurality of buffer spring (407)'s one end all connects jointly on contact piece (406), and is a plurality of buffer spring (407)'s the other end all connects jointly on holding tank (403).

2. A high pressure fuel pump as set forth in claim 1, wherein: the bottom of the oil conveying chamber (2) is provided with an impurity discharging groove (7), and the inner wall of the impurity discharging groove (7) is provided with an air hole communicated with the outside.

3. A high pressure fuel pump as set forth in claim 1, wherein: the bottom of the piston rod (4) is movably connected with a second sealing ring (13), the top of the second sealing ring (13) is provided with a plurality of guide grooves (14), and the guide grooves (14) are uniformly distributed on the top of the second sealing ring (13).

4. A high pressure fuel pump as set forth in claim 3, wherein: outer wall fixed mounting of sealing washer two (13) has outer go-between (8), the outer wall of outer go-between (8) and the bottom inner wall fixed connection of oil transportation room (2), annular hold up tank (9) have been seted up at the top of outer go-between (8), relief hole (10) have been seted up to the outer wall of outer go-between (8), supporting spring (12) are installed, and are a plurality of to the inner wall of annular hold up tank (9) the top of supporting spring (12) is connected with filter screen (11) jointly, the tip of filter screen (11) and the interior wall connection of annular hold up tank (9).

5. The high pressure fuel pump of claim 4, wherein: the inner wall fixedly connected with honeycomb duct (15) of relief hole (10), the one end that relief hole (10) were kept away from in honeycomb duct (15) is connected with stock solution chamber (16), the tip fixed mounting of stock solution chamber (16) has back flow (17), oil inlet pipe (18) are installed at the top of back flow (17).

6. The high pressure fuel pump of claim 5, wherein: the outer wall fixed mounting who advances oil pipe (18) has the admission valve, the one end of advancing oil pipe (18) and the inner wall fixed connection of oil transportation room (2), the one end fixedly connected with who fails the oilhole is seted up in oil transportation room (2) goes out oil pipe (19), the outer wall fixed mounting who goes out oil pipe (19) has check valve (20).

7. A high pressure fuel pump as set forth in claim 1, wherein: one end, far away from the piston rod (4), of the buffering convex button (3) is connected with a first transmission rod (21), the tops of the first transmission rods (21) are connected with a damper (22) together, and the bottom of the damper (22) is connected with a second transmission rod (23).

Technical Field

The invention relates to the technical field of fuel pumps, in particular to a high-pressure fuel pump.

Background

High pressure fuel pumps, a term of art in the automotive sector. Is one of the basic components of the fuel injection system of the electronic fuel injection automobile. The fuel pressure regulator is used for sucking fuel from a fuel tank, pressurizing the fuel and then conveying the fuel to a fuel supply pipe, and is matched with the fuel pressure regulator to establish certain fuel pressure. The high-pressure oil pump is a key link for fuel oil pressurization, and after the low-pressure oil pump sends fuel oil to the high-pressure oil pump, the high-pressure oil pump can pressurize gasoline to a pressure of more than ten megapascals (which is thirty times of the pressure of a common gasoline pump) and send the gasoline to an oil rail.

The conventional patent (publication number: CN108979924A) comprises a plunger sleeve, a plunger, an oil inlet valve and a sealing ring, wherein a plunger cavity and a valve cavity are arranged in the plunger sleeve, the oil inlet valve is arranged in the valve cavity, an oil inlet cavity is arranged between the end part of the oil inlet valve and the valve cavity, the plunger is arranged in the plunger cavity, and the plunger sleeve is inwards recessed at the position of the plunger cavity to form an accommodating groove. By using the high-voltage assembly, the accommodating groove part can be effectively cooled.

When the plunger piston reciprocates to extrude and convey fuel oil, the plunger sleeve extrudes and impacts the top of the oil conveying chamber, so that the plunger sleeve is damaged, particularly the edge position of the plunger sleeve is easy to wear, the fuel oil leaks along a gap between the plunger sleeve and the oil conveying chamber, impurities contained in the fuel oil are clamped into the inner walls of the plunger piston and the oil conveying chamber during conveying, the movement of the plunger piston is influenced, and further, the fuel oil leaks in a large amount and is stored at the bottom of the oil conveying chamber.

To this end, a high pressure fuel pump is proposed to solve the above problems.

Disclosure of Invention

The invention aims to provide a high-pressure fuel pump, which reduces the impact of a plunger sleeve when the plunger sleeve is close to the top of a fuel delivery chamber through a buffering convex button, avoids the damage of the plunger sleeve caused by the direct impact of the plunger sleeve on the top of the fuel delivery chamber, can guide leaked liquid through a impurity discharging groove, and prevents impurities from being clamped in the plunger sleeve and the fuel delivery chamber so as to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme:

a high-pressure fuel pump comprises a shell and an outer seal shell arranged at the bottom of the shell, wherein a fuel conveying chamber is arranged in the shell, the top of the fuel conveying chamber is connected with a buffering convex button, a fuel conveying hole is arranged at the top of the fuel conveying chamber, a piston rod is movably connected with the inner wall of the fuel conveying chamber, the bottom of the piston rod is connected with a lower connecting frame, the piston rod comprises a plunger rod, a plunger sleeve and a first sealing ring are arranged at the top of the plunger rod, the first sealing ring is clamped in a groove formed between the plunger sleeve and the plunger rod, a containing groove is arranged at the top of the plunger rod, a connecting sleeve is fixedly connected with the inner wall of the containing groove, a contact piece is fixedly arranged at the top of the connecting sleeve, the contact piece, the connecting sleeve and the containing groove form a closed cavity, a buffer spring is arranged in the closed cavity, and one end of each buffer spring is commonly connected to the contact piece, a plurality of buffer spring's the other end all connects on the holding tank jointly.

When the lower link drives the piston rod upward movement, the plunger rod drives the plunger sleeve to move, the contact piece contacts the buffering convex button earlier, the contact piece extrudes the buffer spring, make the buffer spring cushion the plunger rod, alleviate the impact when the plunger sleeve is close to defeated grease chamber top, avoid the direct top that strikes defeated grease chamber of plunger sleeve, make the plunger sleeve harm, the life of extension plunger sleeve, prevent that the fuel from leaking between defeated grease chamber and the plunger sleeve, the sealing washer that sets up simultaneously prevents that the fuel from leaking between plunger sleeve and the plunger rod.

Preferably, the bottom of the oil transmission chamber is provided with an impurity discharging groove, and the inner wall of the impurity discharging groove is provided with an air hole communicated with the outside.

When blocking into impurity between plunger bushing and the oil transportation room, when the plunger bushing moves down, impurity gets into the lower part of plunger bushing and arranges the cavity that forms between the miscellaneous groove, and fall into annular hold up tank along arranging the miscellaneous groove, prevent that impurity in the fuel from causing the plunger bushing damage, arouse the fuel seepage, make the device damage, improve the stability of piston rod operation, and the fuel of oil transportation indoor wall seepage can fall into annular hold up tank through arranging miscellaneous groove water conservancy diversion, avoid liquid to ooze the casing, or get into lubricated chamber dilution lubricating oil.

Preferably, the bottom of the piston rod is movably connected with a second sealing ring, the top of the second sealing ring is provided with guide grooves, and the guide grooves are uniformly distributed on the top of the second sealing ring.

Seal through sealing washer two, avoid the fuel to pass through the plunger rod and get into lubricated portion, dilute lubricating oil, the guiding gutter can lead the drainage to the fuel that leaks from the plunger rod, gets into annular hold up tank in, is convenient for collect the utilization, prevents that liquid from two seepage of sealing washer, influence piston rod operation.

Preferably, the outer wall fixed mounting of sealing washer two has outer go-between, the outer wall of outer go-between and the bottom inner wall fixed connection who defeated grease chamber, annular hold up tank has been seted up at the top of outer go-between, the relief hole has been seted up to the outer wall of outer go-between, supporting spring, a plurality of is installed to the inner wall of annular hold up tank supporting spring's top is connected with the filter screen jointly, the tip of filter screen and the interior wall connection of annular hold up tank.

The inside annular hold up tank that sets up of outer go-between is convenient for store and collects liquid, and the filter screen can prevent impurity jam honeycomb duct to getting rid of the impurity in the fuel, prevents the liquid seepage, and supporting spring advances to support the filter screen, and the fuel in the annular hold up tank can be discharged through the relief hole, avoids the seepage liquid to store up, makes the device damage.

Preferably, the inner wall fixedly connected with honeycomb duct of relief hole, the one end that the relief hole was kept away from to the honeycomb duct is connected with the stock solution chamber, the tip fixed mounting in stock solution chamber has the back flow, the oil inlet pipe is installed at the top of back flow.

Feed liquid that accumulates in the annular holding vessel gets into the honeycomb duct through the relief hole, and liquid gets into the stock solution chamber, and the fuel in the back flow and the fuel that advances in the oil pipe receive the attraction and get into defeated oil chamber, can carry out reuse, practice thrift the fuel to the seepage fuel.

Preferably, an oil inlet valve is fixedly mounted on the outer wall of the oil inlet pipe, one end of the oil inlet pipe is fixedly connected with the inner wall of the oil delivery chamber, an oil outlet pipe is fixedly connected to the end, provided with the oil delivery hole, of the oil delivery chamber, and a check valve is fixedly mounted on the outer wall of the oil outlet pipe.

The fuel oil is extruded by the piston rod and is conveyed from the oil conveying hole to the oil outlet pipe, and the liquid is prevented from flowing back to the oil conveying chamber under the control of the one-way valve, so that the oil way conveying efficiency is improved.

Preferably, one end, far away from the piston rod, of the buffering convex button is connected with a first transmission rod, the tops of the first transmission rods are connected with a damper together, and the bottom of the damper is connected with a second transmission rod.

The damper is transmitted to the vibration borne by the buffering convex button through the first transmission rod, the damper is transmitted to the position of the vibration generated by the operation of the lower connecting frame through the second transmission rod, the vibration is further reduced by the damper, the influence of the vibration on the shell is reduced, the normal operation of other structures in the device is prevented from being influenced by the vibration, and the stability of the device is improved.

Compared with the prior art, the invention has the beneficial effects that:

1. the buffering convex button that can reduce through the setting strikes that the piston rod received, the reinforcing stability, when the plunger rod drives plunger bushing rebound, make the contact piece contact buffering convex button earlier, contact piece extrusion buffer spring makes buffer spring cushion the plunger rod, alleviate the impact when plunger bushing is close to defeated grease chamber top, avoid the direct top that strikes defeated grease chamber of plunger bushing, make the plunger bushing damage, the life of extension plunger bushing prevents that the fuel from leaking between defeated grease chamber and the plunger bushing.

2. Can carry out the drainage to the liquid of seepage through setting up the trash removal groove, prevent that the fuel from flowing down from the oil transportation indoor wall, direct inflow sealing washer two, from two seepage of sealing washer, improve the leakproofness of two departments of sealing washer, prevent simultaneously that blocking from advancing impurity in plunger bushing and the oil transportation room, lead to a large amount of fuel seepage, make two seepage of sealing washer, cause the device to damage, the stability of piston rod operation has been improved, when the plunger bushing moves down, impurity gets into the lower part of plunger bushing and arranges the cavity that forms between the trash removal groove, and fall into annular holding vessel along arranging the trash removal groove.

3. The inside annular hold up tank that sets up of outer go-between is convenient for store and collects liquid, prevents the liquid seepage, gets into the honeycomb duct through the filter screen with impurity removal, the feed liquid that stores up in the annular hold up tank through the relief hole, avoids the seepage liquid to store up, and liquid gets into the stock solution chamber to through the back flow during the oil pipe that advances of backward flow reflux, reuse resources are saved.

Drawings

FIG. 1 is a schematic view of the internal structure of the present invention;

FIG. 2 is a schematic perspective view of a piston rod according to the present invention;

FIG. 3 is a schematic cross-sectional view of a piston rod according to the present invention;

FIG. 4 is a schematic structural diagram of a second seal ring of the present invention;

FIG. 5 is a cross-sectional view of the outer connecting ring of the present invention;

fig. 6 is an enlarged schematic view of a portion a in fig. 1 according to the present invention.

In the figure: 1. a housing; 2. an oil delivery chamber; 3. a buffer convex button; 4. a piston rod; 401. a plunger rod; 402. a plunger sleeve; 403. accommodating grooves; 404. a first sealing ring; 405. connecting sleeves; 406. a contact piece; 407. a buffer spring; 5. a lower connecting frame; 6. an outer seal housing; 7. a trash discharging groove; 8. an outer connecting ring; 9. an annular storage tank; 10. a discharge hole; 11. filtering with a screen; 12. a support spring; 13. a second sealing ring; 14. a diversion trench; 15. a flow guide pipe; 16. a liquid storage cavity; 17. a return pipe; 18. an oil inlet pipe; 19. an oil outlet pipe; 20. a one-way valve; 21. a first transmission rod; 22. a damper; 23. and a second transmission rod.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise. Furthermore, the terms "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Referring to fig. 1 to 6, the present invention provides a high pressure fuel pump, which has the following technical scheme:

a high-pressure fuel pump comprises a shell 1 and an outer sealing shell 6 arranged at the bottom of the shell, wherein an oil conveying chamber 2 is arranged in the shell 1, the top of the oil conveying chamber 2 is connected with a buffering convex button 3, the top of the oil conveying chamber 2 is provided with an oil conveying hole, the inner wall of the oil conveying chamber 2 is movably connected with a piston rod 4, the bottom of the piston rod 4 is connected with a lower connecting frame 5, the piston rod 4 comprises a piston rod 401, the top of the piston rod 401 is provided with a piston sleeve 402 and a sealing ring I404, the sealing ring I404 is clamped in a groove formed between the piston sleeve 402 and the piston rod 401, the top of the piston rod 401 is provided with an accommodating groove 403, the inner wall of the accommodating groove 403 is fixedly connected with a connecting sleeve 405, the top of the connecting sleeve 405 is fixedly provided with a contact piece 406, the connecting sleeve 405 and the accommodating groove 403 form a closed cavity, a buffering spring 407 is arranged in the closed cavity, and one end of each buffering spring 407 is commonly connected to the contact piece 406, the other ends of the plurality of buffer springs 407 are all connected in common to the accommodation groove 403.

The connecting sleeve 405 is flexible and bendable, a cavity formed by the connecting sleeve 405, the contact piece 406 and the accommodating groove 403 is used for sealing and protecting the buffer spring 407, when the lower connecting frame 5 drives the piston rod 4 to move upwards, the plunger rod 401 drives the plunger sleeve 402 to move, the contact piece 406 firstly contacts the buffer convex button 3, the contact piece 406 extrudes the buffer spring 407, the buffer spring 407 buffers the plunger rod 401, the impact when the plunger sleeve 402 approaches the top of the oil delivery chamber 2 is relieved, the plunger sleeve 402 is prevented from directly impacting the top of the oil delivery chamber 2, the plunger sleeve 402 is damaged, the service life of the plunger sleeve 402 is prolonged, fuel is prevented from leaking between the oil delivery chamber 2 and the plunger sleeve 402, the sealing ring I404 is arranged to prevent the fuel from leaking between the plunger sleeve 402 and the plunger rod 401, and the buffer convex button 3 can enable the plunger sleeve 402 to move towards the top of the oil delivery chamber 2 as far as possible while buffering the plunger sleeve 402, reduce the oil transportation residual, improve oil transportation efficiency.

Referring to fig. 6, as an embodiment of the present invention, the bottom of the oil transfer chamber 2 is provided with an impurity discharging groove 7, the inner wall of the impurity discharging groove 7 is provided with an air hole communicated with the outside, the air hole can balance the internal and external air pressures, and the bottom space can realize the air pressure balance when the piston rod 4 moves up and down, without affecting the normal operation of each component.

The impurity discharging groove 7 is arc-shaped, the height of the impurity discharging groove 7 is smaller than the contact height between the plunger sleeve 402 and the inner wall of the oil transportation chamber 2, the plunger sleeve 402 is still damaged in the process of long-term reciprocating motion, fuel oil leaks along the gap between the oil transportation chamber 2 and the plunger sleeve 402, when the fuel oil carrying impurities leaks downwards between the oil transportation chamber 2 and the plunger sleeve 402, the impurities are clamped between the plunger sleeve 402 and the oil transportation chamber 2, when the plunger sleeve 402 moves downwards, the impurities enter a cavity formed between the lower part of the plunger sleeve 402 and the impurity discharging groove 7 and fall into the annular storage groove 9 along the impurity discharging groove 7, the phenomenon that the plunger sleeve 402 is damaged by the impurities in the fuel oil to cause the leakage of the fuel oil is prevented, the device is damaged, the operation stability of the piston rod 4 is improved, and the fuel oil leaking from the inner wall of the oil transportation chamber 2 can fall into the annular storage groove 9 through the impurity discharging groove 7, prevent the fuel oil from entering the outer sealing shell 6 and leaking out of the shell 1 or entering the lubricating cavity, dilute the lubricating oil and reduce the lubricating capability and improve the service performance.

Referring to fig. 4, as an embodiment of the present invention, a second sealing ring 13 is movably connected to the bottom of the piston rod 4, a diversion trench 14 is formed in the top of the second sealing ring 13, and the diversion trenches 14 are uniformly distributed in the top of the second sealing ring 13.

Seal through two sealing washer 13, avoid the fuel to pass through plunger rod 401 and directly get into lubricated portion, dilute lubricating oil, influence lubricated effect, guiding groove 14 can lead the drainage to the fuel that leaks from plunger rod 401, gets into annular holding vessel 9, and the collection of being convenient for is utilized, prevents that liquid from accumulating up, influences the operation of piston rod 4.

Referring to fig. 2, as an embodiment of the present invention, an outer connecting ring 8 is fixedly installed on an outer wall of a second sealing ring 13, the outer wall of the outer connecting ring 8 is fixedly connected with an inner wall of the bottom of the oil transportation chamber 2, an annular storage tank 9 is formed at the top of the outer connecting ring 8, a discharge hole 10 is formed in the outer wall of the outer connecting ring 8, a support spring 12 is installed on the inner wall of the annular storage tank 9, a filter screen 11 is commonly connected to the tops of a plurality of support springs 12, and an end of the filter screen 11 is connected with the inner wall of the annular storage tank 9.

11 flexible of filter screen, the inside annular hold up tank 9 that sets up of outer go-between 8 is convenient for store and collects liquid, filter screen 11 can separate fuel and impurity, get rid of the impurity in the fuel, prevent that impurity from blockking up honeycomb duct 15, prevent the liquid seepage, supporting spring 12 advances to support filter screen 11, it is protruding to make filter screen 11, increase filter screen 11 filter area, fuel in the annular hold up tank 9 can discharge through relief hole 10, avoid seepage liquid to store up, make the device damage.

Referring to fig. 6, a guide pipe 15 is fixedly connected to the inner wall of the discharge hole 10, a liquid storage chamber 16 is connected to one end of the guide pipe 15 far away from the discharge hole 10, a return pipe 17 is fixedly mounted at the end of the liquid storage chamber 16, and an oil inlet pipe 18 is mounted at the top of the return pipe 17.

Feed liquid accumulated in the annular storage tank 9 enters the flow guide pipe 15 through the discharge hole 10, the liquid enters the liquid storage cavity 16, when the piston rod 4 moves downwards to absorb oil, the one-way valve 20 is closed, the oil inlet valve is opened, fuel oil in the return pipe 17 and fuel oil in the oil inlet pipe 18 are sucked to enter the oil conveying chamber 2, leaked fuel oil can be reused, and fuel oil is saved.

Referring to fig. 1, an oil inlet valve is fixedly installed on an outer wall of an oil inlet pipe 18, one end of the oil inlet pipe 18 is fixedly connected to an inner wall of an oil transfer chamber 2, an oil outlet pipe 19 is fixedly connected to an end of the oil transfer chamber 2 where an oil transfer hole is opened, and a check valve 20 is fixedly installed on an outer wall of the oil outlet pipe 19.

The fuel oil is extruded by the piston rod 4 and is conveyed from the oil conveying hole to the oil outlet pipe 19, and is controlled by the one-way valve 20, so that the liquid is prevented from flowing back to the oil conveying chamber 2, and the oil way conveying efficiency is improved.

Referring to fig. 1, as an embodiment of the present invention, one end of the buffer knob 3 away from the piston rod 4 is connected with a first transmission rod 21, the tops of the two first transmission rods 21 are both connected with a damper 22, and the bottom of the damper 22 is connected with a second transmission rod 23.

The vibration borne by the buffering convex button 3 is transmitted to the damper 22 through the first transmission rod 21, the vibration generated by the operation of the lower connecting frame 5 can be transmitted to the damper 22 through the second transmission rod 23, the influence of the vibration on the shell 1 is reduced, the vibration is further reduced through the damper 22, the influence of the vibration on the normal operation of other structures in the device is avoided, and the stability of the device is improved.

The working principle is as follows: when the lower connecting frame 5 drives the piston rod 4 to move upwards, the plunger rod 401 drives the plunger sleeve 402 to move, the contact piece 406 firstly contacts the buffering convex button 3, the contact piece 406 extrudes the buffering spring 407, the buffering spring 407 buffers the plunger rod 401 to reduce the impact when the plunger sleeve 402 is close to the top of the oil delivery chamber 2, the first transmission rod 21 transmits the vibration borne by the buffering convex button 3 to the damper 22 to reduce the influence of the vibration on the shell 1, the plunger sleeve 402 is damped by the buffering convex button 3 in the long-term reciprocating motion process, but still damaged, fuel oil leaks along the gap between the oil delivery chamber 2 and the plunger sleeve 402, when fuel oil carrying impurities leaks downwards between the oil delivery chamber 2 and the plunger sleeve 402, the impurities are clamped between the plunger sleeve 402 and the oil delivery chamber 2, the plunger sleeve 402 moves downwards, the top of the plunger sleeve 402 is connected with the inner wall of the oil delivery chamber 2, impurities in the plunger sleeve 402 and the oil delivery chamber 2 can enter a cavity formed between the lower part of the plunger sleeve 402 and the impurity discharging groove 7 and fall into the annular storage groove 9 along the impurity discharging groove 7, fuel leaked from the inner wall of the oil delivery chamber 2 can be guided into the annular storage groove 9 through the impurity discharging groove 7, when the fuel leaks through a gap between the plunger rod 401 and the plunger sleeve 402, the fuel flows into the annular storage groove 9 on the outer connecting ring 8 through the guide groove 14 on the second sealing ring 13, feed liquid stored in the annular storage groove 9 is filtered through the filter screen 11, the impurities are removed, the fuel enters the guide pipe 15 through the discharge hole 10, the liquid enters the liquid storage cavity 16, when the piston rod 4 moves downwards, the one-way valve 20 is closed, the oil inlet valve is opened and flows back to the oil inlet pipe 18 through the return pipe 17, the fuel in the return pipe 17 and the fuel in the oil inlet pipe 18 are sucked into the oil delivery chamber 2, the leaked fuel can be reused.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.