An inlet structure of a fuel pump

Abstract

The present invention discloses an inlet structure of a fuel pump, which relates to the technical field of fuel pumps and includes an inlet pipe provided on the fuel pump for the flow of oil. A pressure-flow exhaust mechanism for eliminating air in the oil in the inlet pipe to prevent the occurrence of air binding problems is provided on the inlet pipe. The pressure-flow exhaust mechanism includes an annular base, and the annular base includes an integrally formed inner step portion. A conical sealing seat coaxially arranged with the annular base is provided on the annular base. The conical sealing seat includes an integrally formed inclined conical surface. A conical channel for the flow of oil is formed between the inner step portion and the inclined conical surface. The present invention utilizes the Venturi effect and the Bernoulli effect to generate a low pressure at the conical channel, and sucks the gas at the bent portion into the special-shaped sealed seat through the connecting pipe, thereby preventing the gas from entering the pump body, effectively solving the air binding phenomenon caused by gas accumulation when the fuel pump sucks oil, ensuring the normal operation of the fuel pump, and avoiding problems such as insufficient fuel flow or pressure fluctuation.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel pumps, and particularly to an inlet structure of a fuel pump. Background Art

[0002] A fuel pump is a core component in a fuel system, and its main function is to extract fuel from a fuel tank and deliver it to a fuel injection system or a carburetor of an engine at a certain pressure. A non-variable displacement fuel pump realizes fluid transportation by converting the energy of a working fluid into kinetic energy and then converting the kinetic energy into potential energy including fluid pressure energy. Common non-variable displacement fuel pumps include turbine type, vane type, etc.

[0003] Chinese Patent (Publication No.: CN117345688A), this solution specifically includes an inlet pipe, a valve seat, a volute, an oil pump port, two guide fins, a support frame, a rotating shaft, an elastic component, and a valve plate. The valve seat is installed on the fuel pump housing and is located at the inlet part of the fuel pump; a support frame is provided on the valve seat, a rotating shaft is installed in the support frame, two valve plates are installed on the rotating shaft, and the valve plates are pressed by an elastic component; the oil pump port is installed on the fuel pump core and is inserted into the volute; the guide fins are a radially inward extension structure of the oil pump port, and the two guide fins are arranged oppositely and cross with the valve plates; the stability of the fuel pump under low-flow conditions is improved.

[0004] When air enters the pump body during the operation of the existing fuel pump, the air will occupy the internal space of the pump, resulting in problems such as the pump being unable to normally transport fuel, insufficient flow rate, and pressure fluctuation. At the same time, during the vehicle driving process, the oil in the fuel tank may shake, causing air bubbles to exist in the oil, and these air bubbles will be sucked into the pump body along with the oil. When the inlet structure of the fuel pump in the above patent is used, it is difficult to effectively break the air bubbles that may exist in the oil, and thus it is difficult to eliminate or reduce the gas entering the pump body. Furthermore, the fuel pump may experience problems such as insufficient fuel flow rate or pressure fluctuation due to air binding during use. Therefore, an inlet structure of a fuel pump is proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide an inlet structure of a fuel pump, which has the advantage of effectively solving the air binding phenomenon caused by gas accumulation when the fuel pump sucks oil, and solves the problems of insufficient fuel flow rate or pressure fluctuation that may occur due to air binding during the use of the fuel pump.

[0006] To achieve the above purpose, the present invention provides the following technical solution: An inlet structure of a fuel pump includes an inlet pipe for oil flow provided on the fuel pump. The middle part of the inlet pipe includes an integrally formed bent part, and a pressure-flow exhaust mechanism for eliminating air in the oil in the inlet pipe to prevent air binding problems is provided on the inlet pipe.

[0007] The pressure-flow exhaust mechanism comprises an annular base fixedly connected to the inner wall of the inlet pipe, the annular base comprises an integrally formed inner step portion, a conical sealing seat coaxially arranged therewith is provided on the annular base, the conical sealing seat comprises an integrally formed oblique conical surface, and a conical channel for oil liquid to flow is formed between the inner step portion and the oblique conical surface;

[0008] The annular base is provided with a plurality of groups of micro-diameter holes communicating with the gas between the conical channels, and the annular base is provided with an annular cavity communicating with the gas between the plurality of groups of micro-diameter holes;

[0009] The inlet pipe is fixedly connected with a special-shaped closed seat which is in communication with the gas between the annular cavity grooves. The special-shaped closed seat is provided with a connecting pipe which is in communication with the gas at the bend part, and the special-shaped closed seat is provided with a self-discharging component which sucks the gas at the bend part.

[0010] Preferably, the cross-sectional area of the tapered channel is smaller than the cross-sectional area of the annular base.

[0011] Preferably, a bubble-blocking net for oil flow is fixedly connected to the inner wall of the bend portion.

[0012] Preferably, a positioning ring is fixedly connected to the annular base, a guide pin is fixedly connected to one end of the conical sealing seat facing the positioning ring, and a circular hole for the guide pin to slide through is opened on the positioning ring;

[0013] The outer peripheral surface of the guide pin is sleeved with a yield spring, and the two ends of the yield spring are respectively fixedly connected to the positioning ring and the conical sealing seat.

[0014] Preferably, the self-draining component comprises an air-containing chamber opened in a special-shaped closed seat, an air-sealing plate is slidably arranged in the air-containing chamber, and an outer peripheral surface of the air-sealing plate is in sliding contact with an inner wall of the air-containing chamber;

[0015] The special-shaped sealed seat and the connecting pipe are fixedly connected, and the end of the connecting pipe away from the special-shaped sealed seat is fixedly connected to the bending part, and the connecting pipe and the gas containing chamber are gas-connected.

[0016] Preferably, the inner wall of the special-shaped sealed seat includes an integrally formed extending tooth portion, a retaining ring is fixedly connected to the extending tooth portion, and a metal spring is fixedly connected to the inner circumference of the retaining ring;

[0017] The air-containing chamber is located below the metal spring, and an oil-sealing chamber filled with oil is provided above the air-containing chamber. A pressure column is fixedly connected to one side of the metal spring facing the air-containing chamber, and the pressure column is fixedly connected to the air sealing plate.

[0018] A transverse pipeline communicating with the gas between the oil sealing chamber is fixedly passed through the special-shaped sealed seat, and one end of the transverse pipeline away from the special-shaped sealed seat is fixedly passed through the inlet pipeline and communicated with the gas between the annular cavity groove.

[0019] Preferably, a plug block is fixed to the special-shaped sealed seat by threads. Limit posts are fixedly connected to the opposite surfaces of the plug block and the metal elastic sheet. A return spring is sleeved on the two groups of limit posts, and the two ends of the return spring are fixedly connected to the plug block and the metal elastic sheet respectively.

[0020] Preferably, an air outlet pipe is fixedly penetrated through the air storage chamber. A group of one-way valves are respectively fixedly connected to the air outlet pipe and the connection pipe, and the valve ports of the two groups of one-way valves are in opposite directions.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] By providing a pressure-flow exhaust mechanism, the present invention utilizes the Venturi effect and Bernoulli effect to generate a low pressure at the conical channel, and sucks the gas at the bent part into the special-shaped sealed seat through the connection pipe, thereby preventing the gas from entering the pump body, effectively solving the air binding phenomenon caused by gas accumulation when the fuel pump sucks oil, ensuring the normal operation of the fuel pump, and avoiding problems such as insufficient fuel flow or pressure fluctuation.

[0023] By providing a self-draining component, the present invention can automatically perform exhaust operations according to the low pressure generated by the oil flow and automatically reset when the oil suction stops, discharging the gas in the air storage chamber, providing a reserved space for the subsequent discharge of air in the oil, realizing the automation of exhaust and reset, and eliminating the need for manual intervention.

[0024] By providing a bubble-blocking net, when the oil flows through the bubble-blocking net, the bubbles will collide and aggregate on the surface of the bubble-blocking net to form larger bubbles. This aggregation effect makes the bubbles easier to burst and accumulate together. By aggregating and bursting the bubbles, the bubble-blocking net can significantly improve the gas discharge efficiency in the oil, reduce the residence time of gas in the oil, and thus effectively prevent the occurrence of air binding phenomenon. Description of the Drawings

[0025] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0026] Figure 2 It is a schematic diagram of the component where the annular base of the present invention is located;

[0027] Figure 3 For the present invention Figure 2 The enlarged view at A;

[0028] Figure 4 It is a schematic diagram of the component where the positioning through-ring of the present invention is located;

[0029] Figure 5 It is a schematic diagram of the component where the metal elastic sheet of the present invention is located;

[0030] Figure 6For the present invention Figure 5 Enlarged view at position B in the present invention;

[0031] Figure 7 Schematic diagram of the initial position of the conical sealing seat of the present invention;

[0032] Figure 8 Schematic diagram of the positional relationship between the inner stepped portion and the inclined conical surface when the oil fluid flows through in the present invention.

[0033] In the figure: 1. Inlet pipeline; 101. Bent portion; 2. Anti-foam net; 3. Annular base; 301. Inner stepped portion; 4. Conical sealing seat; 401. Inclined conical surface; 5. Positioning through-ring; 6. Guide pin; 7. Yielding spring; 8. Micro-diameter hole; 9. Annular cavity; 10. Special-shaped sealing seat; 11. Tooth-extending portion; 12. Clamping ring; 13. Metal elastic sheet; 14. Oil-sealing chamber; 15. Plug; 16. Return spring; 17. Pressing column; 18. Air-sealing plate; 19. Air-containing chamber; 20. Connecting pipeline. Specific embodiments

[0034] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0035] Please refer to Figures 1 to 8 , the present invention provides a technical solution: a fuel pump inlet structure, including an inlet pipeline 1 provided on the fuel pump for the flow of oil fluid. The middle part of the inlet pipeline 1 includes an integrally formed bent portion 101. A pressure-flow exhaust mechanism for eliminating the air in the oil fluid in the inlet pipeline 1 to prevent the occurrence of air binding problems is provided on the inlet pipeline 1;

[0036] The pressure-flow exhaust mechanism includes an annular base 3 fixedly connected to the inner wall of the inlet pipeline 1. The annular base 3 includes an integrally formed inner stepped portion 301. A conical sealing seat 4 coaxially arranged with the annular base 3 is provided on the annular base 3. The conical sealing seat 4 includes an integrally formed inclined conical surface 401. A conical channel for the flow of oil fluid is formed between the inner stepped portion 301 and the inclined conical surface 401;

[0037] A plurality of groups of micro-diameter holes 8 communicating with the gas in the conical channel are formed on the annular base 3, and an annular cavity 9 communicating with the gas between the plurality of groups of micro-diameter holes 8 is formed on the annular base 3;

[0038] An irregular sealed seat 10 that is fixedly connected to the inlet pipe 1 and communicates with the annular cavity 9 is provided. The irregular sealed seat 10 is provided with a connecting pipe 20 that communicates with the gas at the bent part 101, and the irregular sealed seat 10 is provided with a self-draining component for sucking the gas at the bent part 101.

[0039] As Figure 1 , Figure 2 , Figure 5 , Figure 7 and Figure 8 shown, when the fuel pump sucks the oil, the oil enters the pump body through the inlet pipe 1, and the oil can push the conical sealing seat 4 to move a certain distance in the annular base 3, so as to form a conical channel for the oil to flow through between the inclined conical surface 401 and the inner step 301.

[0040] At the same time, when the oil flows from the annular base 3 through the conical channel, the cross-sectional size area of the conical channel is smaller than the cross-sectional size area of the annular base 3. Then, under the Venturi effect, the flow rate of the oil increases when passing through the conical channel. Among them, the Venturi effect is expressed as: when a fluid (liquid or gas) passes through a pipe, when the cross-sectional area of the pipe suddenly becomes smaller, the velocity of the fluid will increase, and at the same time the pressure will decrease; therefore, when the pump body sucks the oil, the flow rate of the oil passing through the conical channel increases.

[0041] At the same time, the Bernoulli effect refers to that in the steady flow of an ideal fluid, along the streamline, the sum of the kinetic energy, potential energy and static pressure energy of the fluid per unit volume remains unchanged. Then, when the flow rate of the oil at the conical channel increases, a low-pressure phenomenon will occur at its position. Therefore, this low-pressure phenomenon will be transmitted to the annular cavity 9 through a plurality of micro-diameter holes 8 communicating with the conical channel, and the low pressure will be transmitted to the inside of the irregular sealed seat 10 through the annular cavity 9.

[0042] Among them, when there is gas in the oil at the bent part 101, the low pressure generated at the irregular sealed seat 10 will suck the gas at the bent part 101 through the connecting pipe 20, so as to promote the gas to enter the irregular sealed seat 10, thereby ensuring that the gas is guided out of the bent part 101, so as to eliminate or reduce the amount of gas entering the pump body, so as to avoid the phenomenon of air binding in the pump body, so as to avoid problems such as insufficient fuel flow or pressure fluctuation.

[0043] To ensure that the bubbles in the oil can gather and arrange, a bubble-blocking net 2 for the oil to flow through is fixedly connected to the inner wall of the bent part 101. When the oil flows at the bent part 101, its flow direction changes and passes through the position where the bubble-blocking net 2 is located. When the oil flows through the bubble-blocking net 2, the bubbles inside it will collide with the surface of the bubble-blocking net 2 and gather to form larger bubbles. When the bubbles are larger, they will burst with the expansion of the bubble-blocking net 2 to release the air wrapped inside.

[0044] Meanwhile, the connection position between the connecting pipe 20 and the bent part 101 is at the highest level in the bent part 101. Thus, the gas in the bubble will basically gather at the connection position between the connecting pipe 20 and the bent part 101 after rupture. Then, when the subsequent oil fluid flows through the conical channel position, the tightening of the channel size can prompt the special-shaped sealing seat 10 to actively suck the gas gathered at the bent part 101 into it. And when the suction process of the oil fluid stops, the gas in the special-shaped sealing seat 10 can be discharged automatically to ensure that during the subsequent oil fluid suction process, a reserved space is provided for the air in the subsequent oil fluid.

[0045] Further, a positioning through-ring 5 is fixedly connected to the annular base 3. One end of the conical sealing seat 4 facing the positioning through-ring 5 is fixedly connected with a guiding pin 6, and a circular hole for the guiding pin 6 to slide through is formed in the positioning through-ring 5.

[0046] A yielding spring 7 is sleeved on the outer peripheral surface of the guiding pin 6, and both ends of the yielding spring 7 are fixedly connected to the positioning through-ring 5 and the conical sealing seat 4 respectively.

[0047] As Figure 1 、 Figure 2 、 Figure 4 、 Figure 7 and Figure 8 shown, when the fuel pump sucks the oil fluid medium, it can sequentially pass through the positions of the conical sealing seat 4 and the positioning through-ring 5. Among them, when sucking the oil fluid, the suction force prompts the oil fluid to squeeze the inclined conical surface 401, so as to prompt the conical sealing seat 4 and the guiding pin 6 thereon to move towards the positioning through-ring 5. Then, at this time, the yielding spring 7 undergoes a compressive deformation. Thus, when the oil fluid flows, a conical channel for the oil fluid to flow through can be provided by the inner step part 301 and the inclined conical surface 401, so as to achieve the purpose of changing the flow cross-sectional size when the oil fluid passes through the annular base 3 and the conical channel position.

[0048] Further, the self-discharge component includes an air storage chamber 19 formed in the special-shaped sealing seat 10. An air sealing plate 18 is slidably arranged in the air storage chamber 19, and the outer peripheral surface of the air sealing plate 18 is in sliding contact with the inner wall of the air storage chamber 19.

[0049] The special-shaped sealing seat 10 is fixedly connected and communicated with the connecting pipe 20, and one end of the connecting pipe 20 far from the special-shaped sealing seat 10 is fixedly connected and communicated with the bent part 101. The connecting pipe 20 is in gas communication with the air storage chamber 19.

[0050] As Figure 1 and Figure 5As shown, when the oil fluid passes through the annular base 3 and the conical channel in sequence, due to the smaller cross-sectional size at the conical channel, under the Venturi effect, the flow rate of the oil fluid at the conical channel is faster. Thus, under the Bernoulli effect, the negative pressure generated at the conical channel is transmitted to the special-shaped closed seat 10. When there is air at the bent part 101, it can prompt the air sealing plate 18 to move upward, so as to extract the gas accumulated at the bent part 101 through the connecting pipe 20, so that the gas at this place is sucked into the special-shaped closed seat 10, timely exhausting the gas and preventing the gas from accumulating in the bent part 101 and following the oil fluid into the pump body, thus avoiding the phenomenon of air binding.

[0051] On the basis of the self-draining component embodiment, the inner wall of the special-shaped closed seat 10 includes an integrally formed tooth-extending part 11. A clamping ring 12 is clamped and fixed on the tooth-extending part 11, and a metal elastic sheet 13 is fixedly connected to the inner peripheral surface of the clamping ring 12.

[0052] The air storage chamber 19 is located below the metal elastic sheet 13. There is an oil-sealing chamber 14 filled with oil fluid above the air storage chamber 19. A pressure column 17 is fixedly connected to the side of the metal elastic sheet 13 facing the air storage chamber 19. The pressure column 17 is fixedly connected to the air sealing plate 18. A transverse pipe that is gas-communicated with the oil-sealing chamber 14 is fixedly penetrated on the special-shaped closed seat 10. One end of the transverse pipe far from the special-shaped closed seat 10 is fixedly penetrated on the inlet pipe 1 and is gas-communicated with the annular cavity 9.

[0053] A plug 15 is threadedly fixed on the special-shaped closed seat 10. Limiting columns are fixedly connected to the opposite surfaces of the plug 15 and the metal elastic sheet 13. A return spring 16 is sleeved on the two groups of limiting columns, and the two ends of the return spring 16 are respectively fixedly connected to the plug 15 and the metal elastic sheet 13.

[0054] An air outlet pipe is also fixedly penetrated on the air storage chamber 19. One-way valves are respectively fixedly connected to the air outlet pipe and the connecting pipe 20, and the valve ports of the two groups of one-way valves are in opposite directions.

[0055] As Figure 1 、 Figure 2 、 Figure 3 、 Figure 5 and Figure 6 shown, when the oil fluid flows through the conical channel formed by the inner step part 301 and the inclined conical surface 401, the negative pressure phenomenon generated at this position is transmitted to the oil-sealing chamber 14 through the micro-diameter hole 8, the annular cavity 9 and the transverse pipe. The oil-sealing chamber 14 is filled with oil fluid during actual use. Thus, when there is accumulated gas at the bent part 101, when the metal elastic sheet 13 deforms upward, it can drive the air sealing plate 18 to move upward synchronously through the pressure column 17, so as to prompt the gas at the bent part 101 to enter the air storage chamber 19 through the connecting pipe 20.

[0056] When there is no accumulated gas in the bent part 101, the low-pressure phenomenon at the horizontal pipeline is difficult to be transmitted to the oil-sealing chamber 14. This low-pressure phenomenon will drive the oil in the oil-sealing chamber 14 to have a tendency to move towards the annular cavity 9 and the micro-diameter hole 8, that is, it will promote the upward deformation of the metal elastic sheet 13 and the upward movement of the pressure column 17 and the air-sealing plate 18. However, since the end of the connecting pipeline 20 far from the air-containing chamber 19 is in contact with the oil in the bent part 101, it is difficult to drive the oil in the bent part 101 to enter the air-containing chamber 19 through the connecting pipeline 20. Therefore, when there is no gas in the bent part 101, when the oil flows through the conical channel, it is difficult to make up for this low-pressure phenomenon through the oil in the oil-sealing chamber 14. Thus, there will be no obvious deformation at this time, and the oil in the bent part 101 will not be sucked into the air-containing chamber 19.

[0057] At the same time, when there is accumulated gas in the bent part 101, under the action of the low pressure at the conical channel, at this time, part of the oil in the oil-sealing chamber 14 enters the horizontal pipeline, which promotes the upward deformation of the metal elastic sheet 13 and drives the return spring 16 to undergo a compressive deformation, thereby driving the pressure column 17 and the air-sealing plate 18 to move upward to suck the gas at the bent part 101 through the connecting pipeline 20. At the same time, when the pump body stops sucking oil, the conical seal 4 plugs the annular base 3 under the action of the elastic potential energy of the yielding spring 7, and under the action of the elastic potential energy of the return spring 16, it drives the metal elastic sheet 13 to restore its deformation, and replenishes the oil inside the oil-sealing chamber 14 through a small amount of oil in the annular base 3.

[0058] Among them, when the metal elastic sheet 13 restores its deformation, it drives the pressure column 17 and the air-sealing plate 18 to move downward to promote the gas in the air-containing chamber 19 to be discharged from the air outlet pipeline. It should be noted that two one-way valves with opposite valve port directions are fixedly arranged on both the connecting pipeline 20 and the air outlet pipeline to limit the flow direction of the gas, so that the gas accumulated at the bent part 101 can enter the air-containing chamber 19 through the connecting pipeline 20, and when the metal elastic sheet 13 deforms and resets, it can promote the gas in the air-containing chamber 19 to be discharged through the outlet pipeline, thereby preventing the gas from flowing back into the bent part 101 through the connecting pipeline 20 again.

[0059] It should be noted that during the actual use process, the plug 15 is in threaded fit with the special-shaped closed seat 10. Therefore, before assembling the special-shaped closed seat 10, the plug 15 can be unscrewed to facilitate adding oil to the oil-sealing chamber 14 in the special-shaped closed seat 10. At the same time, it can also drive the return spring 16 to be in contact connection with the plug 15, so as to facilitate the assembly operation of the plug 15. And during the actual use, the plug 15 seals the oil-sealing chamber 14 to prevent the oil in the oil-sealing chamber 14 from leaking.

[0060] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A fuel pump inlet structure, including an inlet pipe provided on the fuel pump for the circulation of oil, characterized in that: The middle part of the inlet pipe includes an integrally formed bending part, and the inlet pipe is provided with a pressure flow exhaust mechanism for eliminating air in the oil in the inlet pipe to prevent air binding problems; The pressure-flow exhaust mechanism comprises an annular base fixedly connected to the inner wall of the inlet pipe, the annular base comprises an integrally formed inner step portion, a conical sealing seat coaxially arranged therewith is provided on the annular base, the conical sealing seat comprises an integrally formed oblique conical surface, and a conical channel for oil liquid to flow is formed between the inner step portion and the oblique conical surface; The annular base is provided with a plurality of groups of micro-diameter holes communicating with the gas between the conical channels, and the annular base is provided with an annular cavity communicating with the gas between the plurality of groups of micro-diameter holes; The inlet pipe is fixedly connected with a special-shaped closed seat in communication with the gas between the annular cavity grooves, the special-shaped closed seat is provided with a connecting pipe in communication with the gas at the bend part, and the special-shaped closed seat is provided with a self-draining component for sucking the gas at the bend part; The self-draining component includes an air-containing chamber opened in the special-shaped sealed seat, an air-sealing plate is slidably arranged in the air-containing chamber, and the outer peripheral surface of the air-sealing plate is in sliding contact with the inner wall of the air-containing chamber, the special-shaped sealed seat and the connecting pipe are fixedly connected, and the end of the connecting pipe away from the special-shaped sealed seat is fixedly connected with the bending part, and the connecting pipe and the air-containing chamber are gas-connected; The inner wall of the special-shaped sealed seat includes an integrally formed extending tooth portion, a retaining ring is fixedly connected to the extending tooth portion, and a metal spring is fixedly connected to the inner circumferential surface of the retaining ring, the air-containing chamber is below the metal spring, and an oil-sealing chamber filled with oil is provided above the air-containing chamber, a pressure column is fixedly connected to the side of the metal spring facing the air-containing chamber, and the pressure column is fixedly connected to the air-sealing plate, and a transverse pipeline in gas communication with the oil-sealing chamber is fixedly passed through the special-shaped sealed seat, and one end of the transverse pipeline away from the special-shaped sealed seat is fixedly passed through the inlet pipeline and is in gas communication with the annular cavity groove; The special-shaped closed seat is threadedly fixed with a plug block, and the opposite surfaces of the plug block and the metal spring sheet are fixedly connected with limit posts, and the two groups of limit posts are sleeved with return springs, and the two ends of the return springs are respectively fixedly connected to the plug block and the metal spring sheet; An air outlet pipe is fixedly passed through the air containing chamber, and a group of one-way valves are fixedly connected to the air outlet pipe and the connecting pipe respectively, and the valve ports of the two groups of one-way valves are in opposite directions.

2. The inlet structure of a fuel pump according to claim 1, characterized in that: The cross-sectional area of the tapered channel is smaller than the cross-sectional area of the annular base.

3. The inlet structure of a fuel pump according to claim 1, characterized in that: The inner wall of the bending portion is fixedly connected with a bubble-blocking net for oil liquid circulation.

4. The inlet structure of a fuel pump according to claim 1, characterized in that: A positioning ring is fixedly connected to the annular base, a guide pin is fixedly connected to one end of the conical sealing seat facing the positioning ring, and a circular hole is provided on the positioning ring for the guide pin to slide through; The outer peripheral surface of the guide pin is sleeved with a yield spring, and the two ends of the yield spring are respectively fixedly connected to the positioning ring and the conical sealing seat.

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