Roller pin assembly, guide piston and fuel injection pump

Abstract

The present invention discloses a roller pin assembly, a guide piston and a fuel injection pump, wherein the roller pin assembly comprises a stop pin, a return spring, a roller body, a bushing which is gap-fitted in the roller body and a roller pin which is gap-fitted in the bushing, a lubricating oil groove is arranged on the outer wall of the roller pin, and a plurality of through holes are distributed on the bushing, and the through holes can introduce the lubricating oil in the lubricating oil groove into between the roller body and the bushing; the guide piston comprises a piston body and a roller pin assembly; the fuel injection pump comprises an isobaric oil outlet valve assembly, a fuel injection pump body, a plunger pair, a rack adjustment mechanism, an upper spring disk assembly, a plunger spring, a lower spring seat, a hard block and a guide piston. The roller pin assembly, the guide piston and the fuel injection pump provided by the present invention can improve the reliability and service life of the roller pin assembly, increase the structural strength, stability and service life of the fuel injection pump, and improve the efficiency of the fuel injection pump assembly and the installation of the fuel injection pump on the diesel engine.

Description

Technical Field

[0001] The invention relates to the technical field of diesel engines, and in particular to a roller pin assembly, a guide piston and a fuel injection pump. Background Art

[0002] As people's requirements for energy conservation and environmental protection continue to increase, improving diesel engine technology to achieve higher fuel economy and better emission levels has attracted more and more attention from manufacturers. Today, ultra-high pressure fuel injection has become the inevitable development direction of fuel injection systems with its potential advantages in improving economy and emissions. However, to achieve ultra-high pressure fuel injection, the pump end pressure must be greatly increased, which leads to an increase in the contact stress between the roller body and the cam, and the contact stress between the roller body and the bushing, and between the roller pin and the bushing in the roller pin assembly. The mechanical wear between the roller and the bushing, and between the roller pin and the bushing. The roller pin assembly is one of the main components of the fuel injection pump, and its working condition directly affects the quality of the fuel injection pump. In order to ensure the normal operation of the roller pin assembly, it must have good lubrication, but the conventional roller pin assembly structure cannot meet the increasingly stringent working conditions. It is necessary to study new technologies to improve the reliability and service life of the roller pin assembly, so as to meet the use requirements of high-strength fuel injection pumps. At the same time, the pump end pressure is greatly increased, and higher requirements are placed on the structural strength and performance of the injection pump. The existing injection pumps suitable for four-stroke, exhaust gas turbocharged, intercooled, and irreversible diesel engines (such as CN201620491459) cannot meet the development needs of diesel engines in terms of structural strength, stability, and service life, and there are many structures that need further improvement. Summary of the invention

[0003] In view of this, the purpose of the present invention is to overcome the defects in the prior art and provide a roller pin assembly, a guide piston and a fuel injection pump, which can improve the reliability and service life of the roller pin assembly, improve the structure of the fuel injection pump, increase the structural strength, stability and service life of the fuel injection pump, and simplify the installation process of the fuel injection pump. It can not only simplify the assembly process when assembling the fuel injection pump and improve the assembly efficiency when assembling the fuel injection pump, but also simplify the installation process of the fuel injection pump on the diesel engine and improve the assembly efficiency of the fuel injection pump on the diesel engine.

[0004] A roller pin assembly of the present invention comprises a stop pin, a return spring, a roller body, a bushing gap-fitted in the roller body and a roller pin gap-fitted in the bushing, wherein the left and right ends of the roller pin are provided with protrusions protruding from the bushing; a lubricating oil groove is provided on the outer wall of the roller pin, and a lubricating oil channel is provided inside the roller pin, the head end of the lubricating oil channel leads to the outside, and the end of the lubricating oil channel leads to the lubricating oil groove; a plurality of through holes are distributed on the bushing, and the through holes can guide the lubricating oil in the lubricating oil groove into between the roller body and the bushing; a mounting hole is provided on the protrusion, and the axis of the mounting hole is along the radial direction of the roller pin, the return spring is installed in the mounting hole, the head end of the stop pin extends out of the protrusion, and the end of the stop pin is located in the mounting hole and connected to the return spring.

[0005] Furthermore, the plurality of through holes are spaced axially along the bushing to form N groups of lubricating oil hole groups, and each group of the lubricating oil hole group is composed of M through holes spaced circumferentially along the bushing; and P lubricating oil grooves are spaced circumferentially along the roller pin, and the axial lengths of the P lubricating oil grooves are greater than the axial distance between the leftmost lubricating oil hole group and the rightmost lubricating oil hole group.

[0006] Furthermore, the spacing between two adjacent groups of lubricating oil hole groups is the same, the spacing between two adjacent through holes in each group of lubricating oil hole groups is the same, and the spacing between two adjacent lubricating oil grooves is the same; each group of lubricating oil hole groups is staggered by β° from left to right along the same rotation direction.

[0007] Furthermore, a positioning adjustment hole is provided on one side end surface of the roller pin; a lubricating oil inlet is provided on the protruding portion, and the head end of the lubricating oil channel is connected to the lubricating oil inlet.

[0008] The present invention also discloses a guide piston, comprising a piston body and a roller pin assembly as described above, wherein an installation space for accommodating the roller pin assembly is provided at the bottom of the piston body, wherein the installation space comprises a transverse hole for accommodating the roller pin and a vertical groove for accommodating the roller body and the bushing, wherein the transverse hole and the vertical groove are perpendicular to and connected to each other, wherein the bottom of the roller body protrudes from the vertical groove, and a positioning hole for accommodating the head end of the stop pin is provided inside the transverse hole at a position corresponding to the installation hole.

[0009] The present invention also discloses a fuel injection pump, comprising an isobaric oil delivery valve assembly, a fuel injection pump body, a plunger pair, a rack adjustment mechanism, an upper spring disk assembly, a plunger spring, a lower spring seat and a hard block, wherein the fuel injection pump body is provided with a center hole in the up and down directions, the isobaric oil delivery valve assembly is arranged on the top of the fuel injection pump body, the plunger pair, the rack adjustment mechanism, the upper spring disk assembly, the plunger spring, the lower spring seat and the hard block are all installed in the center hole, and also comprises the guide piston as described above, wherein the guide piston is connected to the bottom of the lower spring seat.

[0010] Furthermore, a lifting threaded hole is provided on the isobaric oil outlet valve assembly, and a high-pressure fuel outlet hole communicating with the outside is also provided on the isobaric oil outlet valve assembly, and the bottom of the high-pressure fuel outlet hole is a spherical surface.

[0011] Furthermore, an inverted "U"-shaped groove is provided at the bottom of the fuel injection pump body, and the spacing between the two side walls of the inverted "U"-shaped groove increases radially outwardly along the fuel injection pump body. A first scale line is provided on the two side walls of the inverted "U"-shaped groove, and a second scale line is provided on the guide piston corresponding to the position of the first scale line.

[0012] Furthermore, the plunger pair includes a plunger sleeve and a plunger rod slidably arranged inside the plunger sleeve; a plunger sleeve oil return hole is arranged on the plunger sleeve, and a corrosion-resistant screw is arranged at a position of the fuel injection pump body corresponding to the plunger sleeve oil return hole, and an corrosion-resistant concave surface is arranged at one end of the corrosion-resistant screw facing the plunger sleeve oil return hole, and the corrosion-resistant concave surface is recessed in a direction away from the plunger sleeve oil return hole; the plunger sleeve oil return hole includes an oil hole portion and an opening portion located on a side of the oil hole portion close to the corrosion-resistant screw, and the opening direction of the opening portion is toward the corrosion-resistant concave surface; a protective boss is arranged on the top of the plunger rod.

[0013] Furthermore, it also includes a first locating pin and a second locating pin, the upper and lower ends of the first locating pin are respectively connected to the isobaric oil delivery valve assembly and the fuel injection pump body, and the upper and lower ends of the second locating pin are respectively connected to the isobaric oil delivery valve assembly and the plunger pair; the bottom of the isobaric oil delivery valve assembly is provided with a first locating pin mounting groove for accommodating the first locating pin, and the first locating pin mounting groove is connected to the outside along the radial direction of the fuel injection pump body.

[0014] The beneficial effects of the present invention are as follows: a roller pin assembly, a guide piston and a fuel injection pump disclosed by the present invention, since a plurality of through holes are provided on the bushing, lubricating oil can fully enter the gap between the roller body and the bushing, and a uniformly distributed lubricating oil film can be formed between the roller body and the bushing through the rotation of the roller body and the floating of the bushing; since a lubricating oil groove is provided on the roller pin and there is a gap between the bushing and the roller pin, a uniformly distributed lubricating oil film can also be formed between the floating bushing and the roller pin, effectively improving the mechanical wear between the bushing and the roller body and between the bushing and the roller pin, thereby improving the reliability and service life of the roller pin assembly, and further improving the reliability and service life of the guide piston; by improving the structure of the fuel injection pump, increasing the structural strength, stability and service life of the fuel injection pump, not only can the assembly process when assembling the fuel injection pump be simplified and the assembly efficiency when assembling the fuel injection pump be improved, but also the installation process of installing the fuel injection pump on the diesel engine can be simplified and the assembly efficiency of installing the fuel injection pump on the diesel engine can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0016] Figure 1 It is a cross-sectional schematic diagram of the fuel injection pump of the present invention;

[0017] Figure 2 It is a structural schematic diagram of the fuel injection pump of the present invention;

[0018] Figure 3 It is a structural schematic diagram of the isobaric oil outlet valve assembly of the present invention;

[0019] Figure 4 It is a structural schematic diagram of the plunger pair of the present invention;

[0020] Figure 5 It is a structural schematic diagram of the upper spring disk assembly of the present invention;

[0021] Figure 6 It is a structural schematic diagram of the guide piston of the present invention;

[0022] Figure 7 It is a schematic diagram of the local structure of the present invention;

[0023] Figure 8 It is a structural schematic diagram of the roller pin assembly of the present invention;

[0024] Fig. 9 It is a schematic structural diagram of the bushing of the present invention;

[0025] Fig.10 It is a schematic structural diagram of the roller pin of the present invention.

[0026] Description of main reference numerals: 1-isobaric oil outlet valve assembly, 101-oil outlet valve, 102-pressure reducing valve, 103-high-pressure fuel outlet hole, 104-lifting threaded hole, 105-first positioning pin installation groove, 2-fuel injection pump body, 201-corrosion-resistant screw, 202-inverted "U"-shaped groove, 203-first scale line, 3-plunger pair, 301-plunger sleeve, 302-plunger rod, 303-protective boss, 304-plunger sleeve into the oil return hole, 304a-oil hole part, 304b-opening part, 4-rack adjustment mechanism, 5-upper spring disk assembly, 51-upper large cylinder, 52-lower small cylinder, 53-sealing ring, 54-assembly threaded hole, 6-plunger spring, 7-lower spring seat, 8-hard block, 9-guide piston, 901-piston body, 902-second scale line, 11-roller pin assembly, 110-stop pin, 111-reset spring, 112-roller body, 113-bushing, 113a-through hole, 114-roller pin, 114a-lubricating oil groove, 114b-lubricating oil inlet, 114c-positioning adjustment hole, 12-bleed screw, 13-second positioning pin, 14-bleed hole, 15-washer. DETAILED DESCRIPTION

[0027] like Figure 8-Figure 10 As shown, the roller pin assembly 11 in this embodiment includes a stop pin 110, a return spring 111, a roller body 112, a bushing 113 gap-fitted in the roller body 112, and a roller pin 114 gap-fitted in the bushing 113, and the left and right ends of the roller pin 114 are both provided with protrusions protruding from the bushing 113; a lubricating oil groove 114a is provided on the outer wall of the roller pin 114, and a lubricating oil channel is provided inside the roller pin 114, the head end of the lubricating oil channel leads to the outside, and the end of the lubricating oil channel leads to the outside. The lubricating oil groove 114a is provided with a plurality of through holes 113a on the bushing 113, and the through holes 113a can guide the lubricating oil in the lubricating oil groove 114a into between the roller body 112 and the bushing 113; the protruding portion is provided with a mounting hole, and the axis of the mounting hole is along the radial direction of the roller pin 114, the return spring 111 is installed in the mounting hole, the head end of the stop pin 110 extends out of the protruding portion, and the rear end of the stop pin 110 is located in the mounting hole and connected to the return spring 111;

[0028] The plurality of through holes 113a are spaced axially along the bushing 113 to form N groups of lubricating oil hole groups, each group of the lubricating oil hole group is composed of M through holes 113a spaced circumferentially along the bushing 113; the lubricating oil grooves 114a are spaced circumferentially along the roller pin 114, and the axial lengths of the P lubricating oil grooves 114a are greater than the axial distance between the leftmost lubricating oil hole group and the rightmost lubricating oil hole group; the spacing between two adjacent groups of the lubricating oil hole groups is the same , the distance between two adjacent through holes 113a of each group of the lubricating oil hole groups is the same, and the distance between two adjacent lubricating oil grooves 114a is the same; the lubricating oil hole groups of each group are staggered by β° from left to right along the same rotation direction, and the preferred value of β is 10, 20, 30 or 45; a positioning adjustment hole 114c is provided on one end surface of the roller pin 114; a lubricating oil inlet 114b is provided on the protruding portion, and the head end of the lubricating oil channel is connected to the lubricating oil inlet 114b.

[0029] In this embodiment, the number of through holes 113a is 12, N=3, M=4, P=2, β=30; each group of lubricating oil hole groups is staggered by 30° from left to right along the same rotation direction, and a space for accommodating lubricating oil is formed between the two lubricating oil grooves 114a and the inner wall of the bushing 113. The lubricating oil enters the lubricating oil channel from the lubricating oil inlet 114b, and then enters the lubricating oil groove 114a, and then the lubricating oil enters between the bushing 113 and the roller body 112 from each through hole 113a. As the roller body 112 and the bushing 113 rotate, a lubricating oil film is formed between the bushing 113 and the roller body 112, which effectively improves the mechanical wear between the bushing 113 and the roller body 112; the axial lengths of the two lubricating oil grooves 114a are both greater than the axial distance between the leftmost lubricating oil hole group and the rightmost lubricating oil hole group, which can ensure that the lubricating oil in the lubricating oil groove 114a can smoothly enter each through hole 113a. The first group of lubricating oil holes rotates 30° counterclockwise (or clockwise) with the central axis of the bushing 113 as the center and overlaps with the second group of lubricating oil holes. The second group of lubricating oil holes rotates 30° counterclockwise (or clockwise) with the central axis of the bushing 113 as the center and overlaps with the third group of lubricating oil holes. This design can make the three groups of lubricating oil holes staggered evenly, making it easier to form a uniformly distributed lubricating oil film between the bushing 113 and the roller body 112. The roller body 112 and the bushing 113 are clearance fits, and the bushing 113 and the roller pin 114 are also clearance fits. Therefore, the bushing 113 is floating, which can make the distribution of the lubricating oil film more uniform, improve the failure of parts caused by dry friction, and improve the reliability of the roller pin assembly 11 and the service life of the roller pin assembly 11. A positioning adjustment hole 114c is provided on the right end face of the roller pin 114. The positioning adjustment hole 114c can be a square hole or a round hole. When a round hole is used, the positioning adjustment hole 114c is not located at the rotation center of the roller pin 114. When the roller pin assembly 11 is assembled into the guide piston 9, the stop pin 110 and the return spring 111 are first installed in the mounting hole of the roller pin 114, and then the stop pin 110 is pressed to compress the return spring 111, and the roller pin 114 is installed in the piston body 901. Since the head end of the stop pin 110 does not necessarily face the positioning hole on the piston body 901, the head end of the stop pin 110 cannot enter the positioning hole to achieve the positioning effect. At this time, a tool can be used to insert the positioning adjustment hole 114c, and the roller pin 114 is rotated until the head end of the stop pin 110 enters the positioning hole on the piston body 901, thereby simplifying the assembly process when assembling the injection pump and improving the assembly efficiency when assembling the injection pump.

[0030] like Figure 6As shown, the present invention also discloses a guide piston 9, including a piston body 901 and the roller pin assembly 11 as described above, the bottom of the piston body 901 is provided with an installation space for accommodating the roller pin assembly 11, the installation space includes a transverse hole for accommodating the roller pin 114 and a vertical groove for accommodating the roller body 112 and the bushing 113, the transverse hole and the vertical groove are perpendicular to each other and connected, the bottom of the roller body 112 protrudes from the vertical groove, and the position of the transverse hole corresponding to the installation hole is provided with a positioning hole for accommodating the head end of the stop pin 110. The stop pin 110 can be used to prevent the roller pin 114 from rotating, and the roller body 112 and the bushing 113 can both rotate.

[0031] like Figure 1-Figure 6 As shown, the present invention also discloses a fuel injection pump, comprising an isobaric oil delivery valve assembly 1, a fuel injection pump body 2, a plunger pair 3, a rack adjustment mechanism 4, an upper spring disk assembly 5, a plunger spring 6, a lower spring seat 7 and a hard block 8, the fuel injection pump body 2 is provided with a middle hole in the up and down directions, the isobaric oil delivery valve assembly 1 is arranged at the top of the fuel injection pump body 2, the plunger pair 3, the rack adjustment mechanism 4, the upper spring disk assembly 5, the plunger spring 6, the lower spring seat 7 and the hard block 8 are all installed in the middle hole, and also comprises the guide piston 9 as described above, and the guide piston 9 is connected to the bottom of the lower spring seat 7. The cam of the diesel engine cooperates with the plunger spring 6 of the fuel injection pump to make the guide piston 9 reciprocate in the up-down direction, thereby driving the plunger rod 302 in the plunger pair 3 to reciprocate in the up-down direction. The top of the plunger rod 302 forms a pump chamber with the plunger sleeve 301. The isobaric oil outlet valve assembly 1 is provided with an oil outlet valve chamber and a pressure reducing valve chamber. The pump chamber is communicated with the oil outlet valve chamber and the pressure reducing valve chamber at the same time. The oil outlet valve chamber is provided with an oil outlet valve 101, and the pressure reducing valve 102 is provided in the pressure reducing valve chamber. During the oil supply stroke, when the oil pressure in the pump chamber increases and is greater than the opening pressure of the oil outlet valve 101, the oil outlet valve 101 overcomes the elastic force of the spring and opens, and the high-pressure fuel in the pump chamber enters the high-pressure oil pipe from the high-pressure fuel outlet hole 103; after the oil supply is completed, the pump chamber becomes a low-pressure chamber, and the high-pressure fuel in the high-pressure oil pipe flows back into the pump chamber through the high-pressure fuel outlet hole 103. When the high-pressure fuel is lower than a certain set value, the oil outlet valve 101 is closed. If the sum of the oil pressure in the high-pressure chamber due to pressure wave transmission and superposition is higher than the opening pressure of the pressure reducing valve 102, the pressure reducing valve 102 opens, the high-pressure fuel enters the low-pressure chamber, and the oil pressure in the oil channel is released.

[0032] like Figure 3As shown, in this embodiment, the isobaric oil outlet valve assembly 1 is provided with a lifting threaded hole 104, and the isobaric oil outlet valve assembly 1 is also provided with a high-pressure fuel outlet hole 103 communicating with the outside, and the bottom of the high-pressure fuel outlet hole 103 is a spherical surface. The lifting threaded hole 104 can facilitate the lifting of the fuel injection pump, simplify the lifting and positioning process during lifting, thereby improving the assembly efficiency of the fuel injection pump installed on the diesel engine, and the bottom of the high-pressure fuel outlet hole 103 is a spherical surface, which is conducive to reducing the stress concentration at this part.

[0033] like Figure 7 As shown, in this embodiment, an inverted "U"-shaped groove 202 is provided at the bottom of the fuel injection pump body 2, and the spacing between the two side walls of the inverted "U"-shaped groove 202 increases radially outwardly of the fuel injection pump body 2, and a first score line 203 is provided on the two side walls of the inverted "U"-shaped groove 202, and a second score line 902 is provided on the guide piston 9 at a position corresponding to the first score line 203. The spacing between the two side walls of the inverted "U"-shaped groove 202 increases radially outwardly of the fuel injection pump body 2, and the preferred solution is that the two side walls of the inverted "U"-shaped groove 202 are two inclined surfaces or curved surfaces, so that the first score line 203 can be observed from the outside. In the process of installing the fuel injection pump on the diesel engine, it is necessary to adjust the pre-stroke of the plunger rod 302. Since the guide piston 9 and the plunger rod 302 are connected as one, it is only necessary to adjust the guide piston 9 to the correct height position to adjust the pre-stroke of the plunger rod 302 to the design value. During actual assembly, it is only necessary to adjust the guide piston 9 so that the second score line 902 is aligned with the first score line 203. Therefore, the design of the first score line 203 and the second score line 902 can simplify the process of adjusting the height position of the guide piston 9, thereby simplifying the installation process of the fuel injection pump on the diesel engine, facilitating the installation of the fuel injection pump on the diesel engine, and improving the assembly efficiency of the fuel injection pump installed on the diesel engine.

[0034] like Figure 1 and Figure 3As shown, in this embodiment, the plunger pair 3 includes a plunger sleeve 301 and a plunger rod 302 slidably arranged inside the plunger sleeve 301; a plunger sleeve oil return hole 304 is arranged on the plunger sleeve 301, and a corrosion-resistant screw 201 is arranged at a position corresponding to the plunger sleeve oil return hole 304 of the fuel injection pump body 2, and an corrosion-resistant concave surface is arranged at one end of the corrosion-resistant screw 201 facing the plunger sleeve oil return hole 304, and the corrosion-resistant concave surface is recessed in a direction away from the plunger sleeve oil return hole 304; the plunger sleeve oil return hole 304 includes an oil hole portion 304a and an opening portion 304b located on a side of the oil hole portion 304a close to the corrosion-resistant screw 201, and the opening direction of the opening portion 304b is toward the corrosion-resistant concave surface; a protective boss 303 is arranged on the top of the plunger rod 302. In this embodiment, the axis height position of the anti-corrosion screw 201 is higher than the axis height position of the oil hole portion 304a. Since the oil hole portion 304a is at a lower position, the opening portion 304b gradually tilts upward in the direction close to the anti-corrosion screw 201, so that the opening direction of the opening portion 304b is toward the anti-corrosion concave surface. The traditional anti-corrosion screw adopts a planar structure, and the fuel will splash onto the fuel injection pump body 2 after impacting the end face of the planar structure of the anti-corrosion screw. In the present invention, the opening direction of the opening portion 304b of the plunger sleeve entering the oil return hole 304 is toward the anti-corrosion concave surface. The anti-corrosion concave surface can reduce the splashing of fuel, thereby better controlling the cavitation on the anti-corrosion screw 201 that can be disassembled and replaced, reducing the erosion of the fuel injection pump body 2, and is conducive to extending the service life of the fuel injection pump body 2.

[0035] like Figure 1 and Figure 2 As shown, in this embodiment, a first locating pin (not shown in the figure) and a second locating pin 13 are also included. The upper and lower ends of the first locating pin are respectively connected to the isobaric oil delivery valve assembly 1 and the fuel injection pump body 2, and the upper and lower ends of the second locating pin 13 are respectively connected to the isobaric oil delivery valve assembly 1 and the plunger pair 3. During the assembly process of the fuel injection pump, the second locating pin 13 can provide a positioning basis for the isobaric oil delivery valve assembly 1 and the plunger pair 3. Since the plunger pair 3 is installed in a suspended manner, the isobaric oil delivery valve assembly 1 and the plunger sleeve 301 are connected as a component by screws. The first locating pin can provide a positioning basis for the component and the fuel injection pump body 2, making assembly easier. Figure 2As shown, a first locating pin mounting groove 105 for accommodating the first locating pin is provided at the bottom of the isobaric oil delivery valve assembly 1, and the first locating pin mounting groove 105 is connected with the outside along the radial direction of the fuel injection pump body 2. When the components consisting of the plunger sleeve 301 and the isobaric oil delivery valve assembly 1 are assembled with the fuel injection pump body 2, since the first locating pin mounting hole on the isobaric oil delivery valve assembly 1 is located on the lower end surface of the isobaric oil delivery valve assembly 1, it is not convenient to observe the position of the first locating pin mounting hole, and the diameter of the first locating pin mounting hole is not large, so it is difficult to adjust the position so that the exposed part of the first locating pin on the fuel injection pump body 2 is just inserted into the first locating pin mounting hole on the isobaric oil delivery valve assembly 1. Therefore, the present invention designs the first locating pin mounting hole on the isobaric oil delivery valve assembly 1 to be a first locating pin mounting groove 105. Workers can directly observe the first locating pin mounting groove 105 from the outside. During assembly, it is only necessary to align the exposed portion of the first locating pin on the fuel injection pump body 2 and insert it into the first locating pin mounting groove 105. This makes it more convenient to assemble the components consisting of the plunger sleeve 301 and the isobaric oil delivery valve assembly 1 with the fuel injection pump body 2, simplifies the assembly process of the fuel injection pump, and improves the assembly efficiency of the fuel injection pump assembly.

[0036] like Figure 1 and Figure 5 As shown, the upper spring disk assembly 5 includes an upper spring disk body and two sealing rings 53. The upper spring disk body includes an upper large cylinder 51 and a lower small cylinder 52 arranged in sequence from top to bottom. The plunger spring 6 abuts against the bottom of the large cylinder. An inner hole for the plunger rod 302 to pass through is arranged in the middle of the upper spring disk body. A sealing ring 53 is respectively arranged on the circumference of the upper large cylinder 51 and the top of the inner hole. The sealing ring 53 can prevent the mixed oil from leaking downward and contaminating the lubricating oil; the bottom of the lower small cylinder 52 is provided with an assembly threaded hole 54, and the axial direction of the assembly threaded hole 54 is along the up and down direction. The gap between the upper large cylinder 51 and the fuel injection pump body 2 is small and a sealing ring 53 is provided between the upper spring disk assembly 5 and the fuel injection pump body 2. When installing or removing the upper spring disk assembly 5, it is difficult to move the upper spring disk assembly 5 along the axis direction of the middle hole of the fuel injection pump body 2. After the assembly threaded hole 54 is provided at the bottom of the lower small cylinder 52, when installing or removing the upper spring disk assembly 5, the tool can be directly used to thread the assembly threaded hole 54, and the upper spring disk assembly 5 can be driven to move by the tool, thereby achieving the installation or removal of the upper spring disk assembly 5, further simplifying the assembly process when assembling the fuel injection pump, and improving the assembly efficiency when assembling the fuel injection pump. A washer 15 is provided between the upper spring disk assembly 5 and the shoulder surface of the middle hole of the fuel injection pump body 2, and the preload force of the plunger spring 6 can be adjusted by adjusting the thickness of the washer 15, such as replacing washers 15 of different thicknesses, grinding the thickness of the washer 15 thin, etc.

[0037] like Figure 2As shown, the fuel injection pump body 2 is provided with a bleed screw mounting hole communicating with the pump chamber, and a bleed screw 12 is arranged in the bleed screw mounting hole. The bleed screw 12 is detachable, and the bleed screw 12 can be loosened to discharge the air in the fuel injection pump. Figure 1 and Figure 2 As shown, the fuel injection pump body 2 is provided with a vent hole 14, which enables the cavity of the fuel injection pump body 2 located at the lower side of the upper spring plate assembly 5 to communicate with the outside, thereby balancing the internal and external air pressures of the fuel injection pump body 2 when the guide piston 9 moves.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A fuel injection pump, comprising an isobaric oil delivery valve assembly (1), a fuel injection pump body (2), a plunger pair (3), a rack adjustment mechanism (4), an upper spring plate assembly (5), a plunger spring (6), a lower spring seat (7) and a hard block (8), wherein the fuel injection pump body (2) is provided with a middle hole in the up-down direction, the isobaric oil delivery valve assembly (1) is arranged at the top of the fuel injection pump body (2), the plunger pair (3), the rack adjustment mechanism (4), the upper spring plate assembly (5), the plunger spring (6), the lower spring seat (7) and the hard block (8) are all installed in the middle hole, characterized in that: It also includes a guide piston (9), wherein the guide piston (9) is connected to the bottom of the lower spring seat (7); The guide piston (9) comprises a piston body (901) and a roller pin assembly (11); The roller pin assembly (11) comprises a stop pin (110), a return spring (111), a roller body (112), a bushing (113) loosely mounted in the roller body (112), and a roller pin (114) loosely mounted in the bushing (113); both left and right ends of the roller pin (114) are provided with protrusions protruding from the bushing (113); a lubricating oil groove (114a) is provided on the outer wall of the roller pin (114); a lubricating oil channel is provided inside the roller pin (114); the first end of the lubricating oil channel leads to the outside, and the terminal end of the lubricating oil channel leads to the lubricating oil groove (114a); a plurality of through holes (113a) are distributed on the bushing (113); the through holes (113a) are capable of guiding the lubricating oil in the lubricating oil groove (114a) into between the roller body (112) and the bushing (113); The plurality of through holes (113a) are spaced apart in the axial direction of the bushing (113) to form N groups of lubricating oil holes, each group of the lubricating oil holes being composed of M through holes (113a) spaced apart in the circumferential direction of the bushing (113); The spacing between two adjacent groups of lubricating oil hole groups is the same, and the spacing between two adjacent through holes (113a) in each group of lubricating oil hole groups is the same; and each group of lubricating oil hole groups is staggered by β° from left to right along the same rotation direction.

2. The fuel injection pump according to claim 1, characterized in that: The protruding portion is provided with a mounting hole, the axis of the mounting hole is along the radial direction of the roller pin (114), the return spring (111) is mounted in the mounting hole, the head end of the stop pin (110) protrudes from the protruding portion, and the tail end of the stop pin (110) is located in the mounting hole and connected to the return spring (111); The bottom of the piston body (901) is provided with an installation space for accommodating the roller pin assembly (11), the installation space comprising a transverse hole for accommodating the roller pin (114) and a vertical groove for accommodating the roller body (112) and the bushing (113), the transverse hole and the vertical groove being perpendicular to and connected to each other, the bottom of the roller body (112) protruding from the vertical groove, and a positioning hole for accommodating the head end of the stop pin (110) being provided inside the transverse hole at a position corresponding to the installation hole; The fuel injection pump further comprises a first locating pin and a second locating pin (13), wherein the upper and lower ends of the first locating pin are respectively connected to the isobaric fuel delivery valve assembly (1) and the fuel injection pump body (2), and the upper and lower ends of the second locating pin (13) are respectively connected to the isobaric fuel delivery valve assembly (1) and the plunger pair (3); a first locating pin mounting groove (105) for accommodating the first locating pin is provided at the bottom of the isobaric fuel delivery valve assembly (1), and the first locating pin mounting groove (105) is connected to the outside along the radial direction of the fuel injection pump body (2); The fuel injection pump body (2) is provided with a bleed screw mounting hole which is in communication with the pump cavity. A bleed screw (12) is arranged in the bleed screw mounting hole. The bleed screw (12) is used to discharge air in the fuel injection pump. The fuel injection pump body (2) is provided with a bleed hole (14). The bleed hole (14) enables the cavity of the fuel injection pump body (2) located at the lower side of the upper spring plate assembly (5) to be in communication with the outside, so as to balance the internal and external air pressures of the fuel injection pump body (2) when the guide piston (9) moves.

3. The fuel injection pump according to claim 2, characterized in that: P lubricating oil grooves (114a) are arranged at intervals along the circumference of the roller pin (114), and the axial lengths of the P lubricating oil grooves (114a) are all greater than the axial distance between the leftmost lubricating oil hole group and the rightmost lubricating oil hole group.

4. The fuel injection pump according to claim 3, characterized in that: The distance between two adjacent lubricating oil grooves (114a) is the same.

5. The fuel injection pump according to claim 1, characterized in that: A positioning adjustment hole (114c) is provided on one end surface of the roller pin (114); a lubricating oil inlet (114b) is provided on the protruding portion, and the head end of the lubricating oil channel is connected to the lubricating oil inlet (114b).

6. The fuel injection pump according to claim 2, characterized in that: The isobaric oil outlet valve assembly (1) is provided with a lifting threaded hole (104), and the isobaric oil outlet valve assembly (1) is also provided with a high-pressure fuel outlet hole (103) communicating with the outside, and the bottom of the high-pressure fuel outlet hole (103) is a spherical surface.

7. The fuel injection pump according to claim 6, characterized in that: An inverted "U"-shaped groove (202) is provided at the bottom of the fuel injection pump body (2), the spacing between two side walls of the inverted "U"-shaped groove (202) increases radially outwardly of the fuel injection pump body (2), first engraved lines (203) are provided on the two side walls of the inverted "U"-shaped groove (202), and a second engraved line (902) is provided on the guide piston (9) at a position corresponding to the first engraved line (203).

8. The fuel injection pump according to claim 7, characterized in that: The plunger pair (3) comprises a plunger sleeve (301) and a plunger rod (302) slidably arranged inside the plunger sleeve (301); a plunger sleeve oil return hole (304) is arranged on the plunger sleeve (301); a corrosion-resistant screw (201) is arranged at a position of the fuel injection pump body (2) corresponding to the plunger sleeve oil return hole (304); and the corrosion-resistant screw (201) is arranged at one end thereof facing the plunger sleeve oil return hole (304). There is an anti-corrosion concave surface, the anti-corrosion concave surface is recessed in a direction away from the plunger sleeve entering the oil return hole (304); the plunger sleeve entering the oil return hole (304) comprises an oil hole portion (304a) and an opening portion (304b) located on a side of the oil hole portion (304a) close to the anti-corrosion screw (201), and the opening direction of the opening portion (304b) is toward the anti-corrosion concave surface; and a protective boss (303) is provided on the top of the plunger rod (302).

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