A small locomotive fuel pump assembly

Abstract

This utility model discloses a small locomotive fuel pump assembly belonging to the field of fuel pump technology, including a fuel pump, a pressure relief valve, a pump barrel, and a drive wiring harness. The pump barrel includes an inlet chamber and an outlet chamber. The inlet chamber is provided with a first mounting cylinder and a second mounting cylinder. The bottom of the first mounting cylinder is connected to the outlet chamber and has a fuel pump hole. The second mounting cylinder is connected to the outlet chamber and has a pressure relief hole. The fuel pump passes through the first mounting cylinder, with its outlet end passing through the fuel pump hole. The pressure relief valve passes through the second mounting cylinder. By setting the first and second mounting cylinders, the fuel pump and pressure relief valve are respectively installed in the first and second mounting cylinders. The fuel pump outlet end directly passes through the fuel pump hole and communicates with the outlet chamber. The pressure relief valve passes through the pressure relief hole. This not only improves the installation stability of the fuel pump and pressure relief valve in the pump barrel and prevents the fuel pump from shifting during locomotive operation, but also extends the service life of the fuel pump.

Description

Technical Field

[0001] This utility model relates to the field of fuel pump technology, specifically to a small locomotive fuel pump assembly. Background Technology

[0002] Motorcycles require an electronic fuel injection pump to deliver fuel from the fuel tank to the engine for continuous operation.

[0003] Chinese utility model patent publication number "CN210714896U" discloses a motorcycle fuel pump assembly, including a top cover assembly, a wiring harness assembly, a fuel pump, a pressure reducing valve, and a fuel reservoir. The two ends of the wiring harness assembly are respectively connected to the top cover assembly and the fuel pump. The top cover assembly connects to the fuel reservoir to form a receiving space, and the fuel pump and pressure reducing valve are disposed in the receiving space. The fuel reservoir includes an upper edge connecting part, a fuel pump part, a pressure reducing part, and a bolt locking part. The bolt locking part is a single piece, including a locking plate, two locking holes, and several reinforcing ribs. One side of the locking plate is connected to the outer surface of the fuel pump part, and the other side of the locking plate is connected to the two locking holes. The locking holes protrude from the locking plate, and the several reinforcing ribs connect the outer surface of the locking plate and the outer surface of the locking holes.

[0004] However, the aforementioned motorcycle fuel pump assembly still has the following drawbacks: First, according to paragraphs

[0019] to

[0025] of the instruction manual, the fuel pump and pressure reducing valve are installed inside the fuel tank, and the gap between the fuel pump inlet and the bottom of the fuel tank is filled by a shock-absorbing pad. However, during long-term use, the rubber shock-absorbing pad will dry out and crack, failing to dampen the fuel pump and causing the fuel pump to move around inside the fuel tank during locomotive operation, resulting in a poor service life for the fuel pump.

[0005] Secondly, the fuel pump outputs fuel directly to the motorcycle engine through the fuel outlet pipe assembled on the top cover. However, when the engine stops running, the fuel in the fuel outlet pipe will flow back into the fuel pump assembly, resulting in insufficient fuel pressure in the fuel pipe when the engine is restarted, which cannot meet the needs of the motorcycle engine to start quickly.

[0006] Therefore, it is necessary to improve upon the aforementioned shortcomings. Utility Model Content

[0007] The purpose of this invention is to provide a small locomotive fuel pump assembly that has a stable structure, long service life, and can maintain oil output pressure.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a small locomotive fuel pump assembly, including a fuel pump, a pressure relief valve, a pump barrel, and a drive wiring harness. One end of the pump barrel is fitted with an inlet cap, and the other end is fitted with an outlet cap. The outlet cap is provided with an outlet pipe, and the inlet cap is provided with an inlet pipe and a drain pipe. The pump barrel includes an inlet chamber and an outlet chamber. The inlet chamber is provided with a first mounting cylinder and a second mounting cylinder. The bottom of the first mounting cylinder is connected to the outlet chamber and has a fuel pump hole. The second mounting cylinder is connected to the outlet chamber and has a pressure relief hole. The fuel pump passes through the first mounting cylinder and the fuel pump outlet end passes through the fuel pump hole. The pressure relief valve passes through the second mounting cylinder. One end of the drive wiring harness is fitted with the outlet cap, and the other end is electrically connected to the fuel pump. The operation of the fuel pump causes fuel to be drawn from the inlet pipe into the pump barrel and output from the outlet pipe.

[0009] By adopting the above technical solution: the pump barrel is equipped with a first mounting cylinder and a second mounting cylinder, so that the fuel pump and the pressure relief valve are respectively installed in the first mounting cylinder and the second mounting cylinder. The fuel pump outlet end is directly installed in the fuel pump hole and communicates with the fuel outlet chamber. The pressure relief valve is installed in the pressure relief hole. This not only improves the installation stability of the fuel pump and the pressure relief valve in the pump barrel, preventing the fuel pump from surging during locomotive operation and extending the service life of the fuel pump, but also allows the pressure relief valve to regulate the fuel pressure in the fuel outlet chamber. When the engine stops running, the fuel in the fuel outlet pipe maintains pressure through the pressure relief valve, avoiding fuel backflow that would cause insufficient pressure, and ensuring that the fuel pressure in the fuel pipe meets the requirements for rapid start-up when the engine is restarted.

[0010] The aforementioned small locomotive fuel pump assembly can be further configured as follows: an elastic positioning ring is provided on the outer circumference of the fuel pump, the inner ring of the positioning ring abuts against the fuel pump, and the outer ring abuts against the inner wall of the first mounting cylinder; a receiving cavity is provided at the end of the fuel inlet pipe near the fuel pump on the fuel inlet cap; the fuel pump's sucker pipe passes through the receiving cavity; a first sealing ring is fitted around the outer circumference of the sucker pipe, the inner ring of the first sealing ring abuts against the outer circumference of the sucker pipe, and the outer ring abuts against the inner wall of the receiving cavity; a positioning post is provided on the fuel inlet end face of the fuel pump; a positioning hole is provided on the fuel inlet cap along the axial direction of the positioning post; the positioning post passes through the positioning hole, and the sucker pipe passes through the receiving cavity, causing the end face of the fuel inlet cap to contact the end face of the fuel pump. By adopting the above technical solution: the elastic positioning ring is set between the outer periphery of the fuel pump and the inner wall of the first mounting cylinder, effectively absorbing and buffering the vibration during locomotive operation, preventing hard contact and wear between the fuel pump and the first mounting cylinder. At the same time, its elastic deformation characteristics tightly fill the gap, curbing the axial movement of the fuel pump in the pump barrel, significantly improving the operational stability and service life of the fuel pump. Meanwhile, the first sealing ring forms a reliable radial seal through the tight contact between the inner and outer rings and the oil suction pipe and the receiving cavity wall, effectively preventing fuel leakage in the oil inlet pipe. The precise fit between the positioning pin and the positioning hole ensures the accurate alignment of the fuel pump and the fuel inlet cap during assembly. Combined with the direct contact between the end face of the fuel inlet cap and the end face of the fuel pump, a stable axial positioning is formed, jointly constructing a multi-layer anti-loosening structure, ensuring the connection reliability and sealing durability of the fuel pump assembly under long-term vibration conditions.

[0011] The aforementioned small locomotive fuel pump assembly can be further configured as follows: a support cylinder extends outward from the end of the oil drain pipe near the pressure relief valve, a number of support ribs are distributed at intervals on the inner wall of the support cylinder, the end face of the support cylinder can abut against the end face of the pressure relief valve, a pressure relief notch is opened on the side wall of the support cylinder, and an oil drain groove is provided in the oil inlet cap connected to the oil drain notch.

[0012] By adopting the above technical solution, the support cylinder provides stable axial support for the pressure relief valve through direct contact between its end face and the end face of the pressure relief valve. This effectively limits the axial displacement of the pressure relief valve during operation and locomotive vibration, improving its installation stability. Meanwhile, the several support ribs distributed at intervals on the inner wall of the support cylinder not only achieve radial limiting and support for the pressure relief valve, but also ensure that fuel can flow smoothly through the gaps between the support ribs. In addition, the pressure relief notch and the oil drain groove on the oil inlet cap cooperate with each other to increase the smoothness of oil discharge from the pressure relief valve. This not only ensures timely response and smooth pressure relief process of the pressure relief valve, avoiding pressure abnormalities caused by oil circuit blockage, but also helps to maintain the residual pressure in the oil outlet line, providing a reliable guarantee for the rapid restart of the engine.

[0013] The aforementioned small locomotive fuel pump assembly can be further configured such that: a one-way valve assembly passes through the oil outlet pipe, a mounting boss is provided on the inner wall of the oil outlet pipe, a limiting ring is provided at one end of the oil outlet pipe relative to the fuel pump, one end of the one-way valve assembly abuts against the end face of the mounting boss, and the other end abuts against the limiting ring.

[0014] By adopting the above technical solution, the mounting boss and the limiting ring form a stable axial installation space within the oil outlet pipe, allowing the one-way valve assembly to be precisely defined and pressed within this space. This effectively prevents the one-way valve assembly from shifting under fuel pressure fluctuations or vehicle vibration, ensuring its operational reliability. Simultaneously, the one-way valve assembly achieves stable installation in the oil outlet pipe through tight contact between its two ends and the mounting boss face and the limiting ring, respectively. When the engine stops running, the one-way valve closes promptly, blocking fuel from flowing back into the fuel pump assembly through the oil outlet pipe, thus maintaining residual fuel pressure in the oil outlet pipe. This effectively solves the starting delay problem caused by insufficient fuel line pressure when the engine restarts, ensuring the vehicle can start quickly. Furthermore, the simple mechanical structure improves the reliability and durability of the assembly.

[0015] The aforementioned small locomotive fuel pump assembly can be further configured as follows: a one-way valve assembly includes a valve seat, a valve stem, and a return spring. One end of the valve stem slides with the valve seat, and the other end is provided with a valve head. A first limiting post extends outward from the end of the valve seat near the valve head, and a second limiting post extends outward from the end of the valve head near the valve seat. The return spring passes through the valve stem. One end of the return spring is sleeved on the outer periphery of the first limiting post and abuts against the end face of the valve seat, and the other end is sleeved on the outer periphery of the second limiting post and abuts against the end face of the valve head. The valve head abuts against the mounting boss to achieve closure of the oil outlet pipe.

[0016] By adopting the above technical solution, the sliding fit between the valve seat and the valve stem ensures that the valve head can accurately respond to changes in fuel pressure. When the fuel pump is running, the fuel pressure pushes the valve head to compress the return spring and disengage from the mounting boss, allowing fuel to be smoothly output through the outlet pipe. When the engine stops running, the return spring quickly returns to its original position through the guiding action of the first and second limit posts, pushing the valve head to fit tightly against the mounting boss to achieve a seal. This not only prevents the spring from shifting or twisting during long-term vibration, but also ensures the sealing accuracy of the valve head to the outlet pipe, effectively preventing fuel backflow while reducing valve body wear, and significantly improving the service life and operational reliability of the one-way valve assembly.

[0017] The aforementioned small locomotive fuel pump assembly can be further configured as follows: several sets of sealing grooves are provided at both ends of the pump barrel, and a second sealing ring is provided in the sealing groove; several first buckles are spaced apart on the outer periphery of the fuel outlet cap; several first locking blocks are spaced apart on the outer periphery of the pump barrel near the fuel outlet cap; the first buckles and the first locking blocks cooperate to achieve a detachable connection between the fuel outlet cap and the pump barrel; several second buckles are spaced apart on the outer periphery of the fuel inlet cap; several second locking blocks are spaced apart on the outer periphery of the pump barrel near the fuel inlet cap; the second buckles and the second locking blocks cooperate to achieve a detachable connection between the fuel inlet cap and the pump barrel.

[0018] By adopting the above technical solution, the fuel outlet cap and the pump barrel are quickly assembled through the snap-fit ​​of the first buckle and the first locking block, forming a stable circumferential fixation without the need for additional fasteners. This simplifies the assembly process and reduces production costs. The fuel inlet cap uses the same second buckle and second locking block structure, allowing the sealing caps at both ends of the pump barrel to be disassembled independently. When the fuel pump or pressure relief valve requires maintenance, the corresponding end cap can be opened simply by separating the buckle, significantly shortening maintenance time. At the same time, the elastic snap-fit ​​characteristics of the buckle and locking block can reduce assembly errors, and the second sealing ring can improve the sealing of the connection between the fuel outlet cap, fuel inlet cap, and pump barrel, ensuring a tight fit between the cap and the pump barrel end face and preventing fuel leakage from the connection gap.

[0019] The aforementioned small locomotive fuel pump assembly can be further configured such that: the ends of the first buckle and the second buckle are provided with a first guide slope, and the first block and the second block are provided with a second guide slope, and the first guide slope and the second guide slope cooperate to realize the guide engagement between the first block and the first buckle, and between the second block and the second buckle.

[0020] By adopting the above technical solution, the first guide slope and the second guide slope form an automatic alignment mechanism during the assembly process. When the oil outlet cap or oil inlet cap is pressed against the pump barrel, the radial component force generated by the contact of the slope causes the buckle to slide naturally into the bottom of the buckle block, avoiding the component damage that may be caused by traditional rigid snap-fit. This allows the assembly personnel to complete the installation without precise alignment, significantly improving the assembly efficiency of the production line. At the same time, the slope cooperation can disperse the force on the buckle, prevent buckle breakage caused by local stress concentration, and extend the durability of the connection structure.

[0021] The aforementioned small locomotive fuel pump assembly can be further configured as follows: a first positioning protrusion is provided at one end of the first locking block relative to the oil inlet cap, the first positioning protrusion being able to contact the outer surface of the first buckle; a second positioning protrusion is provided at one end of the second locking block relative to the oil outlet cap, the second positioning protrusion being able to contact the outer surface of the second buckle.

[0022] By adopting the above technical solution: when the first buckle engages with the first buckle block, the first positioning protrusion can prevent the rigid deformation caused by excessive bending of the first buckle, thereby improving the stability of the first buckle structure. The second positioning protrusion can also position the second buckle in the same way as the first positioning protrusion, thereby improving the stability of the fuel pump assembly structure of the small locomotive.

[0023] The aforementioned small locomotive fuel pump assembly can be further configured such that: a number of mounting components are provided on the outer periphery of the pump barrel, the mounting components including a first mounting plate and a second mounting plate, the first mounting plate and the second mounting plate forming a mounting groove.

[0024] By adopting the above technical solution: the first mounting plate and the second mounting plate enable the small locomotive fuel pump assembly to be quickly installed and connected to the locomotive through the mounting slot, thereby improving the ease of installation of the small locomotive fuel pump assembly.

[0025] The beneficial effects of this utility model are as follows: First, by separating the fuel pump and pressure relief valve into a first mounting cylinder and a second mounting cylinder, respectively housing the fuel pump and pressure relief valve in the inlet and outlet chambers of the pump barrel, independent installation and isolation of the components are achieved, reducing mutual interference and improving overall stability. The fuel pump outlet is directly inserted into the pump hole, ensuring efficient fuel flow from the inlet chamber to the outlet chamber, avoiding the fuel pump slippage problem caused by aging shock absorbers in traditional structures, and extending service life. Simultaneously, the design of the outlet pipe, combined with the pump barrel structure, helps control fuel flow direction and reduces the risk of backflow. As a preferred method, the fuel pump is mounted in the first mounting cylinder using an elastic fixing device. This device includes an annular elastic element, whose inner wall is in close contact with the outer surface of the fuel pump, and whose outer wall elastically abuts against the inner wall of the first mounting cylinder. During locomotive operation, the element absorbs vibration through elastic deformation, preventing fuel pump displacement.

[0026] Second, a one-way valve assembly is integrated into the fuel outlet pipe. The one-way valve assembly includes a valve seat, a movable valve stem, and a return spring. When the fuel pump is running, the valve stem is pushed open to allow fuel to flow out. When it stops, the return spring pushes the valve stem to close the flow passage, preventing fuel backflow and ensuring sufficient pressure in the fuel line when the engine starts.

[0027] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the small locomotive fuel pump assembly of this utility model; Figure 2 This is a schematic diagram of the pump barrel of this utility model; Figure 3 This is a schematic diagram of the pump barrel of this utility model from another perspective; Figure 4 This is a schematic diagram of the structure of the fuel pump of this utility model; Figure 5 This is a schematic diagram of the structure of the oil inlet cap of this utility model; Figure 6 This is a schematic diagram of the oil outlet cap of this utility model; Figure 7 This is a cross-sectional schematic diagram of the oil outlet cap of this utility model; Figure 8 This is a schematic diagram of the one-way valve assembly of this utility model; Figure 9 This is a schematic diagram of the pressure relief valve of this utility model; Label annotations: Pump barrel 1, Oil inlet chamber 11, First mounting cylinder 111, Second mounting cylinder 112, Oil pump hole 113, Pressure relief hole 114, Oil outlet chamber 12, Sealing groove 13, Second sealing ring 14, First locking block 15, First positioning protrusion 151, Second locking block 16, Second positioning protrusion 161, Second guide slope 17, Mounting component 18, First mounting plate 181, Second mounting plate 182, Mounting groove 183, Fuel pump 2, Positioning ring 21, Oil suction pipe 22, First sealing ring 23, Positioning Column 24, pressure relief valve 3, drive wiring harness 4, oil inlet cap 5, oil inlet pipe 51, oil outlet pipe 52, receiving cavity 53, positioning hole 54, support cylinder 55, support rib 551, pressure relief notch 552, oil outlet groove 553, second buckle 56, oil outlet cap 6, oil outlet pipe 61, mounting boss 62, limit ring 63, first buckle 64, first guide slope 65, one-way valve assembly 7, valve seat 71, first limit post 711, valve stem 72, valve head 721, second limit post 722, return spring 73. Detailed Implementation

[0029] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0030] A small locomotive fuel pump assembly, such as Figures 1 to 9As shown, the system includes a pump barrel 1, a fuel pump 2, a pressure relief valve 3, and a drive wiring harness 4. One end of the pump barrel 1 is fitted with an inlet cap 5, and the other end is fitted with an outlet cap 6. The outlet cap 6 has an outlet pipe 61, and the inlet cap 5 has an inlet pipe 51 and a drain pipe 52. The pump barrel 1 includes an inlet chamber 11 and an outlet chamber 12. The inlet chamber 11 has a first mounting cylinder 111 and a second mounting cylinder 112. The bottom of the first mounting cylinder 111 connects to the outlet chamber 12 and has an opening for oil... Pump hole 113, second mounting cylinder 112 connects to oil outlet chamber 12 and has pressure relief hole 114. Fuel pump 2 passes through first mounting cylinder 111 and oil outlet end of fuel pump 2 passes through fuel pump hole 113. Pressure relief valve 3 passes through second mounting cylinder 112. One end of drive harness 4 is snapped to oil outlet cap 6 and the other end is electrically connected to fuel pump 2. When fuel pump 2 is running, fuel is drawn from inlet pipe 51 into pump barrel 1 and output from oil outlet pipe 61. The pump barrel 1 is equipped with a first mounting cylinder 111 and a second mounting cylinder 112, through which the fuel pump 2 and the pressure relief valve 3 are respectively installed. The fuel pump 2's outlet end is directly installed in the fuel pump hole 113 and communicates with the fuel outlet chamber 12, while the pressure relief valve 3 is installed in the pressure relief hole 114. This not only improves the installation stability of the fuel pump 2 and the pressure relief valve 3 in the pump barrel 1, preventing the fuel pump 2 from moving during locomotive operation and extending the service life of the fuel pump 2, but also allows the pressure relief valve 3 to regulate the fuel pressure in the fuel outlet chamber 12. When the engine stops running, the fuel in the fuel outlet pipe 61 maintains pressure through the pressure relief valve 3, preventing fuel backflow and insufficient pressure, and ensuring that the fuel pressure in the fuel pipe meets the requirements for rapid start-up when the engine restarts.

[0031] like Figure 1 , Figure 2 As shown, the pump barrel 1 has several sets of mounting parts 18 on its outer periphery. The mounting parts 18 include a first mounting plate 181 and a second mounting plate 182, which form a mounting groove 183. The first mounting plate 181 and the second mounting plate 182 enable the small locomotive fuel pump assembly to be quickly installed and connected to the locomotive through the mounting groove 183, thereby improving the ease of installation of the small locomotive fuel pump assembly.

[0032] The pump barrel 1 has several sets of sealing grooves 13 at both ends, and a second sealing ring 14 is provided in the sealing groove 13. Several first snaps 64 are spaced apart on the outer periphery of the oil outlet cap 6. Several first locking blocks 15 are spaced apart on the outer periphery of the pump barrel 1 near the oil outlet cap 6. The first snaps 64 and first locking blocks 15 cooperate to achieve a detachable connection between the oil outlet cap 6 and the pump barrel 1. Several second snaps 56 are spaced apart on the outer periphery of the oil inlet cap 5. Several second locking blocks 16 are spaced apart on the outer periphery of the pump barrel 1 near the oil inlet cap 5. The second snaps 56 and second locking blocks 16 cooperate to achieve a detachable connection between the oil inlet cap 5 and the pump barrel 1. The oil outlet cap 6 and the pump barrel 1 are quickly assembled through the snap-fit ​​of the first snaps 64 and first locking blocks 15, forming a stable circumferential fixation without the need for additional fasteners, which simplifies the assembly process and reduces production costs. The fuel inlet cap 5 adopts the same second snap-fit ​​56 and second locking block 16 structure, allowing the sealing caps at both ends of the pump barrel 1 to be disassembled independently. When the fuel pump 2 or pressure relief valve 3 needs maintenance, the corresponding end cap can be opened simply by separating the snap-fit, significantly shortening maintenance time. At the same time, the elastic snap-fit ​​characteristics of the snap-fit ​​and locking block can reduce assembly errors, and the second sealing ring 14 can improve the sealing performance of the connection between the fuel outlet cap 6, fuel inlet cap 5 and pump barrel 1, ensuring a tight fit between the cap and the end face of the pump barrel 1, and preventing fuel leakage from the connection gap.

[0033] like Figure 4As shown, the fuel pump 2 has an elastic positioning ring 21 on its outer circumference. The inner ring of the positioning ring 21 abuts against the fuel pump 2, and the outer ring abuts against the inner wall of the first mounting cylinder 111. The fuel inlet cap 5 has a receiving cavity 53 at the end of the fuel inlet pipe 51 near the fuel pump 2. The fuel pump 2's sucker pipe 22 passes through the receiving cavity 53. A first sealing ring 23 is fitted around the outer circumference of the sucker pipe 22. The inner ring of the first sealing ring 23 abuts against the outer circumference of the sucker pipe 22, and the outer ring abuts against the inner wall of the receiving cavity 53. The fuel pump 2's fuel inlet end face has a positioning post 24. The fuel inlet cap 5 has a positioning hole 54 along the axial direction of the positioning post 24. The positioning post 24 passes through the positioning hole 54, and the sucker pipe 22 passes through the receiving cavity 53, causing the end face of the fuel inlet cap 5 to contact the end face of the fuel pump 2. The elastic positioning ring 21 is located between the outer circumference of the fuel pump 2 and the inner wall of the first mounting cylinder 111, effectively absorbing and... The system buffers vibrations during locomotive operation, preventing hard contact and wear between the fuel pump 2 and the first mounting cylinder 111. Simultaneously, its elastic deformation characteristics tightly fill the gap, suppressing axial movement of the fuel pump 2 within the pump barrel 1, significantly improving the operational stability and service life of the fuel pump 2. Furthermore, the first sealing ring 23, through its inner and outer rings tightly abutting against the walls of the oil suction pipe 22 and the receiving cavity 53 respectively, forms a reliable radial seal, effectively preventing fuel leakage from the oil inlet pipe 51. The precise fit between the positioning pin 24 and the positioning hole 54 ensures accurate alignment of the fuel pump 2 and the fuel inlet cap 5 during assembly. Combined with the direct contact between the end face of the fuel inlet cap 5 and the end face of the fuel pump 2, a stable axial positioning is formed, collectively constructing a multi-layered anti-loosening structure. This ensures the connection reliability and sealing durability of the fuel pump assembly under long-term vibration conditions.

[0034] like Figure 5 , Figure 7 As shown, the first latch 64 and the second latch 56 have a first guide slope 65 at their ends, and the first latch block 15 and the second latch block 16 have a second guide slope 17. The first guide slope 65 and the second guide slope 17 cooperate to guide and engage the first latch block 15 with the first latch 64 and the second latch block 16 with the second latch 56. The first guide slope 65 and the second guide slope 17 form an automatic alignment mechanism during assembly. When the oil outlet cap 6 or the oil inlet cap 5 is pressed against the pump barrel 1, the radial force generated by the slope contact causes the latch to slide naturally under the latch block, avoiding component damage that may be caused by traditional rigid engagement. This allows assembly personnel to complete the installation without precise alignment, significantly improving the assembly efficiency of the production line. At the same time, the slope engagement can distribute the force on the latch, preventing latch breakage caused by local stress concentration and extending the durability of the connection structure.

[0035] The first locking block 15 has a first positioning protrusion 151 at one end opposite the oil inlet cap 5, which can contact the outer surface of the first latch 64. The second locking block 16 has a second positioning protrusion 161 at one end opposite the oil outlet cap 6, which can contact the outer surface of the second latch 56. When the first latch 64 is engaged with the first locking block 15, the first positioning protrusion 151 can prevent the rigid deformation caused by excessive bending of the first latch 64, thereby improving the stability of the first latch 64 structure. The second positioning protrusion 161 and the first positioning protrusion 151 can also position the second latch 56, thereby improving the stability of the small locomotive fuel pump assembly structure.

[0036] like Figure 5 As shown, the oil drain pipe 52 extends outward from one end near the pressure relief valve 3 and has a support cylinder 55. The inner wall of the support cylinder 55 has several support ribs 551 distributed at intervals. The end face of the support cylinder 55 can abut against the end face of the pressure relief valve 3. The side wall of the support cylinder 55 has a pressure relief notch 552. The oil inlet cover 5 is connected to the oil drain notch 552 and has an oil drain groove 553. The support cylinder 55 provides stable axial support for the pressure relief valve 3 through direct contact between its end face and the end face of the pressure relief valve 3. This effectively limits the axial displacement of the pressure relief valve 3 during operation and locomotive vibration, improving its installation stability. The several support ribs 551 distributed at intervals on the inner wall of the support cylinder 55 not only achieve radial limiting and support for the pressure relief valve 3, but also ensure that fuel can flow smoothly through the gaps between the support ribs 551. In addition, the pressure relief notch 552 and the oil drain groove 553 on the oil inlet cap 5 cooperate with each other to increase the smoothness of oil discharge of the pressure relief valve 3. This not only ensures that the pressure relief valve 3 responds in a timely manner and the pressure relief process is smooth, avoiding pressure abnormalities caused by oil circuit blockage, but also helps to maintain the residual pressure in the oil outlet pipe 61, providing a reliable guarantee for the rapid restart of the engine.

[0037] like Figure 6 , Figure 7As shown, the oil outlet pipe 61 is provided with a one-way valve assembly 7, and the inner wall of the oil outlet pipe 61 is provided with a mounting boss 62. The end of the oil outlet pipe 61 relative to the fuel pump 2 is provided with a limiting ring 63. One end of the one-way valve assembly 7 abuts against the end face of the mounting boss 62, and the other end abuts against the limiting ring 63. The mounting boss 62 and the limiting ring 63 form a stable axial mounting space within the oil outlet pipe 61, allowing the one-way valve assembly 7 to be precisely defined and pressed within this space. This effectively prevents the one-way valve assembly 7 from shifting under fuel pressure fluctuations or vehicle vibration, ensuring its operational reliability. Simultaneously, the one-way valve assembly 7 achieves stable installation in the oil outlet pipe 61 by tightly contacting the end faces of the mounting boss 62 and the limiting ring 63 at both ends. When the engine stops running, the one-way valve closes promptly, blocking fuel from flowing back into the fuel pump assembly through the oil outlet pipe 61, thus maintaining residual fuel pressure within the oil outlet pipe 61. This effectively solves the starting delay problem caused by insufficient fuel line pressure when the engine restarts, ensuring rapid vehicle start-up. Furthermore, the simple mechanical structure enhances the reliability and durability of the assembly.

[0038] like Figure 8 As shown, the one-way valve assembly 7 includes a valve seat 71, a valve stem 72, and a return spring 73. One end of the valve stem 72 is slidably engaged with the valve seat 71, and the other end is provided with a valve head 721. A first limiting post 711 extends outward from the end of the valve seat 71 near the valve head 721, and a second limiting post 722 extends outward from the end of the valve head 721 near the valve seat 71. The return spring 73 passes through the valve stem 72. One end of the return spring 73 is sleeved on the outer periphery of the first limiting post 711 and abuts against the end face of the valve seat 71, and the other end is sleeved on the outer periphery of the second limiting post 722 and abuts against the end face of the valve head 721. The valve head 721 abuts against the mounting boss 62 to close the oil outlet pipe 61. The sliding fit between valve seat 71 and valve stem 72 ensures that valve head 721 can accurately respond to changes in fuel pressure. When fuel pump 2 is running, fuel pressure pushes valve head 721 to compress return spring 73 and disengage from mounting boss 62, allowing fuel to be smoothly output through outlet pipe 61. When the engine stops running, return spring 73 quickly returns to its original position through the guiding action of first limit post 711 and second limit post 722, pushing valve head 721 to fit tightly against mounting boss 62 to achieve a seal. This not only prevents the spring from shifting or twisting during long-term vibration, but also ensures the sealing accuracy of valve head 721 to outlet pipe 61, effectively preventing fuel backflow while reducing valve body wear, and significantly improving the service life and operational reliability of one-way valve assembly 7.

[0039] It should be noted that, as Figure 9 As shown, the pressure relief valve 3 is a conventional technical means in this field, and will not be described in detail in this embodiment.

[0040] The embodiments described above are merely examples of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these modifications and improvements all fall within the protection scope of this utility model.

Claims

1. A fuel pump assembly for a small locomotive, comprising a fuel pump, a pressure relief valve, a pump barrel, and a drive wiring harness, wherein one end of the pump barrel is fitted with an inlet cap and the other end is fitted with an outlet cap, the outlet cap is provided with an outlet pipe, and the inlet cap is provided with an inlet pipe and a drain pipe, characterized in that: The pump barrel includes an inlet chamber and an outlet chamber. The inlet chamber is provided with a first mounting cylinder and a second mounting cylinder. The bottom of the first mounting cylinder is connected to the outlet chamber and has a pump hole. The second mounting cylinder is connected to the outlet chamber and has a pressure relief hole. The fuel pump passes through the first mounting cylinder and the fuel pump outlet end passes through the pump hole. The pressure relief valve passes through the second mounting cylinder. One end of the drive harness is snapped to the fuel outlet cap and the other end is electrically connected to the fuel pump. The operation of the fuel pump causes fuel to be drawn from the inlet pipe into the pump barrel and output from the outlet pipe.

2. A small engine fuel pump assembly as defined in claim 1, wherein: The fuel pump has an elastic positioning ring on its outer circumference. The inner ring of the positioning ring abuts against the fuel pump, and the outer ring abuts against the inner wall of the first mounting cylinder. The fuel inlet cap has a receiving cavity at the end of the fuel inlet pipe near the fuel pump. The fuel pump's sucker pipe passes through the receiving cavity. The outer circumference of the sucker pipe is fitted with a first sealing ring. The inner ring of the first sealing ring abuts against the outer circumference of the sucker pipe, and the outer ring abuts against the inner wall of the receiving cavity. The fuel pump's fuel inlet end face has a positioning post. The fuel inlet cap has a positioning hole along the axial direction of the positioning post. The positioning post passes through the positioning hole, and the sucker pipe passes through the receiving cavity, causing the fuel inlet cap end face to contact the fuel pump end face.

3. A small engine fuel pump assembly as defined in claim 2 wherein: The oil drain pipe extends outward from the end near the pressure relief valve and has a support cylinder. The inner wall of the support cylinder has several support ribs distributed at intervals. The end face of the support cylinder can abut against the end face of the pressure relief valve. The side wall of the support cylinder has a pressure relief notch. The oil inlet cover is connected to the oil drain notch and has an oil drain groove.

4. A small engine fuel pump assembly as defined in claim 1, wherein: The oil outlet pipe is equipped with a one-way valve assembly. The inner wall of the oil outlet pipe is provided with a mounting boss. The end of the oil outlet pipe that is opposite to the fuel pump is provided with a limiting ring. One end of the one-way valve assembly abuts against the end face of the mounting boss, and the other end abuts against the limiting ring.

5. A small engine fuel pump assembly as defined in claim 4, wherein: The one-way valve assembly includes a valve seat, a valve stem, and a return spring. One end of the valve stem slides with the valve seat, and the other end is provided with a valve head. A first limiting post extends outward from the end of the valve seat near the valve head, and a second limiting post extends outward from the end of the valve head near the valve seat. The return spring passes through the valve stem, with one end sleeved on the outer periphery of the first limiting post and abutting against the end face of the valve seat, and the other end sleeved on the outer periphery of the second limiting post and abutting against the end face of the valve head. The valve head abuts against the mounting boss to seal the oil outlet pipe.

6. A small engine fuel pump assembly as claimed in any one of claims 1 to 5 wherein: The pump barrel has several sets of sealing grooves at both ends, and a second sealing ring is provided in each sealing groove. Several first buckles are spaced apart on the outer periphery of the oil outlet cap, and several first locking blocks are spaced apart on the outer periphery of the pump barrel near the oil outlet cap. The first buckles and first locking blocks cooperate to achieve a detachable connection between the oil outlet cap and the pump barrel. Several second buckles are spaced apart on the outer periphery of the oil inlet cap, and several second locking blocks are spaced apart on the outer periphery of the pump barrel near the oil inlet cap. The second buckles and second locking blocks cooperate to achieve a detachable connection between the oil inlet cap and the pump barrel.

7. A small motorcycle fuel pump assembly according to claim 6 wherein: The first and second buckles are provided with a first guide slope at their ends, and the first and second blocks are provided with a second guide slope. The first and second guide slopes cooperate to achieve the guiding and engaging of the first block with the first buckle and the second block with the second buckle.

8. A small motorcycle fuel pump assembly according to claim 7 wherein: The first locking block has a first positioning protrusion at one end relative to the oil inlet cap, and the first positioning protrusion can contact the outer surface of the first buckle. The second locking block has a second positioning protrusion at one end relative to the oil outlet cap, and the second positioning protrusion can contact the outer surface of the second buckle.

9. A small motorcycle fuel pump assembly according to claim 8 wherein: The pump barrel is provided with several sets of mounting components on its outer periphery. The mounting components include a first mounting plate and a second mounting plate, and the first mounting plate and the second mounting plate form a mounting groove.

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