A fuel injection pump guide piston assembly

Abstract

The purpose of the present invention is to provide a fuel injection pump guide piston assembly to achieve the effect of improving the anti-seizure ability of the guide piston assembly. The technical solution of the present invention is as follows: The present invention provides a fuel injection pump guide piston assembly, including: a guide piston, a first mounting hole is opened at the center position of its upper end surface; a second mounting hole is opened at its lower end surface, and the first mounting hole and the second mounting hole are connected through a connecting hole; a roller assembly, including: a roller installed in the second mounting hole, a roller bushing interference-fitted in the roller, and thrust bearings interference-fitted at both axial ends of the roller; a roller pin, whose clearance is assembled in the roller bushing; a boss is protruding from the hole wall of the second mounting hole, and the boss is in contact with the thrust bearing.

Description

Technical Field

[0001] The invention relates to the field of fuel supply pumps for marine low-speed engines, in particular to a fuel injection pump guide piston assembly. Background Art

[0002] The increasingly stringent emission regulations and the continuous improvement of diesel engine density and power have put forward higher requirements for diesel engine fuel systems. Increasing the injection pressure of fuel is an important way to solve these problems. As a key component of the transmission part of the high-pressure fuel injection pump, the guide piston assembly has a complex structure, variable load conditions, and relative friction between the guide piston assembly and the fuel injection pump body. As the injection pressure continues to increase, the load on the guide piston assembly becomes larger and larger, and it is more prone to seizure. Summary of the invention

[0003] The object of the present invention is to provide a fuel injection pump guide piston assembly to achieve the effect of improving the anti-seizure ability of the guide piston assembly.

[0004] The technical solution of the present invention is:

[0005] The present invention provides a fuel injection pump guide piston assembly, comprising:

[0006] The guide piston has a first mounting hole at the center of its upper end surface; a second mounting hole is formed on its lower end surface, and the first mounting hole and the second mounting hole are connected through a connecting hole;

[0007] The roller assembly comprises: a roller mounted in the second mounting hole, a roller bushing interference-fitted in the roller, and thrust bearings interference-fitted at both axial ends of the roller;

[0008] a roller pin, the clearance of which is fitted in the roller bushing;

[0009] A boss is protrudingly provided on the hole wall of the second mounting hole, and the boss is in contact with the thrust bearing.

[0010] Preferably, the thrust bearing is made of copper alloy;

[0011] A plurality of radial oil grooves are evenly arranged on the end surface of the thrust bearing, and the radial oil grooves are arranged toward the hole wall of the second mounting hole.

[0012] Preferably, a spherical annular groove is provided in the axial direction of the roller, and a circular arc transition connection is formed between the groove bottom of the spherical annular groove and the axial end face of the roller.

[0013] Preferably, a DLC coating is provided on the outer circumferential surface of the roller pin;

[0014] The roller bushing is made of copper alloy.

[0015] Preferably, the outer surface of the roller pin is set as a cylindrical surface, and two-step waist-shaped grooves are respectively set at two positions on the cylindrical surface, and the waist-shaped groove is set in the middle position of the roller pin;

[0016] A small-angle wedge-shaped groove is formed between the first waist-shaped groove located on the outer layer and the outer surface of the roller bushing, and an oil hole is arranged in the second waist-shaped groove located on the inner layer;

[0017] The two oil holes at the two positions are connected through a lubricating oil outlet passage, and the lubricating oil outlet passage is arranged at 90 degrees.

[0018] Preferably, the outer surface of the guide piston is set as a cylindrical surface, and the cylindrical surface is provided with a first circumferential oil groove, a second circumferential oil groove, a first axial oil groove and a vertical groove, the vertical groove is opened in the second circumferential oil groove, and the vertical groove is connected to the first circumferential oil groove and the second circumferential oil groove through the first axial oil groove;

[0019] An inclined hole is also provided on the cylindrical surface, and two ends of the inclined hole are respectively connected to the second circumferential oil groove and the inner wall of the second mounting hole;

[0020] A second axial oil groove communicating with the second circumferential oil groove is also provided on the cylindrical surface;

[0021] The cylindrical surface is also provided with a first straight hole and a second straight hole connected to each other, the first straight hole is connected to the first axial oil groove, and the second straight hole is connected to the first mounting hole;

[0022] A lubricating oil inlet passage is arranged on the outer circumferential surface of the roller pin, the lubricating oil inlet passage is arranged relative to the inclined hole, and the lubricating oil inlet passage is connected to the lubricating oil outlet passage.

[0023] Preferably, a first hole is provided on the hole wall of the second mounting hole;

[0024] A second hole is provided on the outer circumferential surface of the roller pin;

[0025] A spring and a stop pin are placed in the second hole in sequence, and the stop pin partially extends into the first hole.

[0026] Preferably, forced lubrication is adopted between the roller pin and the roller bushing;

[0027] Forced lubrication is adopted between the thrust bearing and the boss.

[0028] Preferably, a first chamfer is provided at the outer circle of the upper end of the guide piston;

[0029] A second chamfer is arranged on the hole wall of the first mounting hole.

[0030] The beneficial effects of the present invention are:

[0031] The anti-seizure capability between the guide piston and the roller assembly, the roller assembly and the roller pin, and the guide piston and the fuel injection pump body is improved; the guide piston has a compact overall structure and a strong load-bearing capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the present invention;

[0033] Figure 2 One of the cross-sectional views of the guide piston of the present invention;

[0034] Figure 3 The second cross-sectional view of the guide piston of the present invention;

[0035] Figure 4 It is a structural schematic diagram of the guide piston of the present invention;

[0036] Figure 5 It is a structural schematic diagram of the roller pin of the present invention;

[0037] Figure 6 It is a structural schematic diagram of the roller assembly of the present invention;

[0038] Figure 7 It is a structural schematic diagram of the thrust bearing of the present invention;

[0039] Explanation of the reference numerals: 1—guide piston; 2—roller; 3—roller pin; 4—spring; 5—stop pin; 6—thrust bearing; 7—hexagon socket flat-end set screw; 8—roller bushing; 9—lubricating oil inlet channel; 10—inclined hole; 11—first hole; 12—boss; 13—connecting hole: 14—first chamfer; 15—second chamfer: 16—second mounting hole: 17—second axial oil groove; 18—first straight hole; 19—second straight hole; 20—first circumferential oil groove; 21-second circumferential oil groove; 22—vertical groove; 23—first axial oil groove; 24—second waist-shaped groove; 25-first waist-shaped groove; 26—second hole; 27—oil hole; 29—spherical ring groove; 30—radial oil groove. DETAILED DESCRIPTION

[0040] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0041] Reference Figures 1 to 7 The present invention provides a fuel injection pump guide piston assembly, comprising:

[0042] A guide piston 1, the outer surface of the guide piston 1 is designed as a cylindrical surface, and a first mounting hole is opened at the center position of its upper end surface, and the first mounting hole is used for use with the plunger and the plunger spring, and for the installation of the lower spring 4 assembly. The connecting hole 13 with the first mounting hole is set at the center position of the upper end surface of the guide piston 1, so that the lubricating oil (A5) can be distributed more evenly on the roller surface; a second mounting hole 16 is opened on its lower end surface, and the second mounting hole 16 is used to fix and support the roller assembly and the roller pin 3. At the same time, the roller assembly and the roller pin 3 are also lubricated through the guide piston 1, wherein the first mounting hole and the second mounting hole 16 are connected through the connecting hole 13.

[0043] like Figure 1 , 6 and 7, the guide piston assembly also includes: a roller assembly, including: a roller 2 installed in the second mounting hole 16, a roller bushing 8 interference-fitted in the roller 2, and thrust bearings 6 interference-fitted at both axial ends of the roller 2; a roller pin 3, whose clearance is assembled in the roller bushing 8, and the outer circumferential surface of the roller pin 3 is a cylindrical surface; wherein, a boss 12 is protrudingly provided on the hole wall of the second mounting hole 16, and the boss 12 is in contact with the thrust bearing 6. For the roller 2, the roller 2 adopts an end groove deformation design to reduce the boundary stress; specifically, for the roller 2, during processing, the outer circle of the roller 2 and the inner hole of the roller 2 are first ground, and then the spherical annular groove 29 at the two axial end faces are grooved. After the grooving is completed, the outer circle and the inner hole generatrix of the roller 2 are naturally deformed into arcs, which can effectively weaken the edge effect of the outer cylindrical surface of the roller 2 and the lateral pressure effect of the inner hole of the roller 2 during the rotation of the roller 2, so that the stress distribution of the inner and outer working surfaces of the roller assembly is balanced, thereby reducing the excessive wear between the roller assembly and the roller pin 3 due to excessive local stress. The roller bushing 8 and the roller 2 are fitted with an interference fit, which increases the relative speed between the moving surface of the roller bushing 8 and the roller pin 3. The end surface of the roller bushing 8 moves at a high speed and forms an effective dynamic pressure oil film with the roller pin 3, thereby improving the dynamic pressure lubrication effect and reducing the probability of biting between the roller bushing 8 and the roller pin 3. The roller 2 and the thrust bearing 6 are fitted with an interference fit, which increases the relative speed between the moving surface of the thrust bearing 6 and the boss 12. The end surface of the thrust bearing 6 moves at a high speed and forms an effective dynamic pressure oil film with the boss 12. The formation of the dynamic pressure oil film can improve the dynamic pressure lubrication effect and reduce the possibility of biting between the thrust bearing 6 and the boss 12. The thrust bearing 6 is provided with a radial oil groove 30 to prevent excessive wear caused by insufficient oil supply to the end surface of the thrust bearing 6 when the boss 12 and the thrust bearing 6 are in close contact.

[0044] When the roller pin 3 is assembled onto the guide piston 1, a spring 4 and a stop pin 5 are provided for limiting the roller pin 3, wherein a first hole 11 is provided on the hole wall of the second mounting hole 16; a second hole 26 is provided on the outer circular surface of the roller pin 3; a spring 4 and a stop pin 5 are placed in the second hole 26 in sequence, and a portion of the stop pin 5 extends into the first hole 11. Specifically, when assembling the roller assembly and the roller pin 3 onto the guide piston 1, firstly, the roller bushing 8 and the thrust bearing 6 are installed onto the roller 2 by cold installation; then, the spring 4 and the stop pin 5 are sequentially placed into the second hole 26 of the roller pin 3; then, the roller assembly is placed at the lower part of the guide piston 1, and the roller pin 3 is sequentially passed through one side of the first hole 11 at the lower end of the guide piston 1, the inner hole of the roller assembly (specifically, the inner hole of the roller bushing 8), and the other side of the first hole 11 at the lower end of the guide piston 1; then, the stop pin 5 is pressed by hand so that its height is lower than the second mounting hole 16, and at the same time, the roller pin 3 is pushed until the stop pin 5 bounces into the first hole 11 of the guide piston 1 under the action of the spring 4.

[0045] like Figure 7 The thrust bearing 6 is made of copper alloy, specifically bronze alloy, which can effectively reduce the friction coefficient between the thrust bearing 6 and the boss 12; at the same time, the impact resistance and self-lubricating properties of the bronze alloy are also utilized. A plurality of radial oil grooves 30 are evenly arranged on the end surface of the thrust bearing 6, and the radial oil grooves 30 are arranged toward the hole wall of the second mounting hole 16. Specifically, there are four radial oil grooves 30. The lubricating oil stored in the radial oil grooves 30 can make the lubrication of the thrust bearing 6 more uniform, and effectively improve the lubrication effect between the thrust bearing 6 and the boss 12.

[0046] like Figure 1 and Figure 6 As shown, a spherical annular groove 29 is provided in the axial direction of the roller 2, and a circular arc transition connection is formed between the groove bottom of the spherical annular groove 29 and the axial end surface of the roller 2. Figure 6 It can be seen that the groove wall of the spherical annular groove 29 is formed in an arc shape, which can effectively weaken the edge effect of the outer cylindrical surface of the roller 2 and the side pressure effect of the inner hole of the roller 2 during the rotation of the roller 2, so that the stress distribution on the inner and outer working surfaces of the roller assembly is balanced, thereby reducing the probability of biting between the roller assembly and the roller pin 3.

[0047] Specifically, the outer surface of the roller pin 3 is provided with a DLC coating; the roller bushing 8 is made of a copper alloy, specifically a bronze alloy. The DLC coating has high hardness, low friction coefficient, wear resistance, and high temperature resistance. When the lubrication between the roller bushing 8 and the roller pin 3 is poor, the friction pair composed of the DLC layer and the roller bushing 8 of the copper alloy bearing can still operate well, which can further reduce the probability of biting between the roller pin 3 and the roller bushing 8.

[0048] like Figure 4 , two-step waist grooves are respectively arranged at two positions on the cylindrical surface of the roller pin 3, and the waist grooves are arranged in the middle position of the roller pin 3; a small-angle wedge groove is formed between the first waist groove 25 located in the outer layer and the outer surface of the roller bushing 8, and a first oil hole 27 is arranged in the second waist groove 24 located in the inner layer; the two oil holes 27 at the two positions are connected through the lubricating oil outlet channel, and the lubricating oil outlet channel is arranged at 90°. The first waist oil groove 25 is set to be a slender waist shape, mainly to make the relative movement of the roller bushing 8 and the roller pin 3 and the contact surface with the lubricating oil longer, so as to make full use of the movement speed of the two moving surfaces and bring the lubricating oil into the friction surface. At the same time, a small-angle wedge oil groove is formed between the first waist groove 25 located in the outer layer and the roller bushing 8 to enhance dynamic pressure lubrication. The second waist groove 24 located in the inner layer is used for lubricating oil storage to ensure sufficient supply of lubricating oil on the friction surface. In short, the setting of the two-step waist-shaped groove can improve the friction condition between the roller bushing 8 and the roller pin 3 and reduce the probability of the two being stuck.

[0049] like Figures 1 to 5The outer surface of the guide piston 1 is set as a cylindrical surface, and the cylindrical surface is provided with a first circumferential oil groove 20 and a second circumferential oil groove 21, a first axial oil groove 23 and a vertical groove 22, the vertical groove 22 is opened in the second circumferential oil groove 21, and the vertical groove 22 is connected to the first circumferential oil groove 20 and the second circumferential oil groove 21 through the first axial oil groove 23; an inclined hole 10 is also provided on the cylindrical surface, and the two ends of the inclined hole 10 are respectively connected to the second circumferential oil groove 21 and the inner wall of the second mounting hole 16; the cylindrical surface A second axial oil groove 17 connected to the second circumferential oil groove 21 is also provided on the cylindrical surface; a first straight hole 18 and a second straight hole 19 connected to each other are also provided on the cylindrical surface, the first straight hole 18 is connected to the first axial oil groove 23, and the second straight hole 19 is connected to the first mounting hole, so as to realize lubrication of the lower spring assembly installed in the first mounting hole; a lubricating oil inlet channel 9 is provided on the outer circumferential surface of the roller pin 3, the lubricating oil inlet channel 9 is arranged relative to the inclined hole 10, and the lubricating oil inlet channel 9 is connected to the lubricating oil outlet channel. That is to say, the lubricating oil flowing out of the fuel injection pump body flows into the second circumferential oil groove 21 through the second axial oil groove 17, and then flows into the first circumferential oil groove 20 through the vertical groove 22 and the first axial oil groove 23, so as to realize the lubrication between the guide piston 1 and the fuel injection pump body. Moreover, because the gap between the guide piston 1 and the fuel injection pump body hole matched therewith is very small, the lubricating oil entering the second axial oil groove 17 and the second circumferential oil groove 21 of the guide piston 1 maintains a certain pressure, and a lubricating oil film can be formed between the outer circle of the guide piston 1 and the pump body hole; at the same time, part of the lubricating oil in the second circumferential oil groove 21 flows into the lubricating oil inlet channel 9 through the inclined hole 10, so as to penetrate into the roller pin 3, and then flows out to the outer circle surface of the roller pin 3 through the oil hole 27, so as to deeply lubricate between the roller pin 3 and the roller bushing 8, and form a lubricating oil film between the roller pin 3 and the roller bushing 8.

[0050] In addition, from Figure 1 It can be seen that a hexagon socket flat-end set screw 7 is installed at the end of the roller pin 3, which can prevent the lubricating oil from leaking out.

[0051] In addition, in this embodiment, forced lubrication is adopted between the roller pin 3 and the roller bushing 8; forced lubrication is adopted between the thrust bearing 6 and the boss 12, and both are lubricated by the lubricating oil flowing out of the roller pin 3 and the roller bushing 8.

[0052] like Figure 1As shown, a first chamfer 14 is provided at the outer circle of the upper end of the guide piston 1; a second chamfer 15 is provided on the hole wall of the first mounting hole, and at the same time, a chamfer is provided at the edge of the oil groove provided on the outer surface of the guide piston 1. The angle range of the above chamfers is between 1 and 10 degrees. When the guide piston 1 and the guide hole on the fuel injection pump body cooperate, a small-angle convergent wedge can be formed, which strengthens the extrusion effect in the dynamic pressure lubrication and increases the oil film thickness on the surface of the guide piston 1 during operation, thereby reducing the probability of biting between the guide piston 1 and the fuel injection pump body.

[0053] The above-mentioned embodiments of the present invention improve the anti-seizure capability between the guide piston 1 and the roller assembly, the roller assembly and the roller pin 3, and the guide piston 1 and the fuel injection pump body. The guide piston 1 has a compact overall structure and a strong load-bearing capacity.

[0054] Although only one or more embodiments of the present invention are described in the above embodiments of the present invention, it should be understood by those skilled in the art that the present invention can be implemented in many other forms without departing from its subject matter and scope. Therefore, the examples and embodiments shown are considered to be illustrative rather than restrictive, and the present invention may include various modifications and substitutions without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A fuel injection pump guide piston assembly, characterized in that: include: The guide piston (1) has a first mounting hole at the center of its upper end surface; a second mounting hole (16) is formed on its lower end surface, and the first mounting hole and the second mounting hole (16) are connected via a connecting hole (13); A roller assembly, comprising: a roller (2) mounted in the second mounting hole (16), a roller bushing (8) interference-fitted in the roller (2), and thrust bearings (6) interference-fitted at both axial ends of the roller (2); A roller pin (3) whose clearance is fitted in the roller bushing (8); A boss (12) is protrudingly provided on the hole wall of the second mounting hole (16), and the boss (12) is in contact with the thrust bearing (6); The outer surface of the roller pin (3) is arranged as a cylindrical surface, and two-step waist-shaped grooves are arranged at two positions on the cylindrical surface, respectively, the two-step waist-shaped grooves comprising a first waist-shaped groove (25) located on the outer layer and a second waist-shaped groove (24) located on the inner layer, and the two-step waist-shaped grooves are arranged in the middle of the roller pin (3); A small-angle wedge-shaped groove is formed between the first waist-shaped groove (25) located on the outer layer and the outer surface of the roller bushing (8), and an oil hole (27) is provided in the second waist-shaped groove (24) located on the inner layer; The oil holes (27) at the two positions are connected via a lubricating oil outlet passage, and the lubricating oil outlet passage is arranged at 90 degrees.

2. The fuel injection pump guide piston assembly according to claim 1, characterized in that: The thrust bearing (6) is made of copper alloy; A plurality of radial oil grooves (30) are evenly arranged on the end surface of the thrust bearing (6), and the radial oil grooves (30) are arranged toward the hole wall of the second mounting hole (16).

3. The fuel injection pump guide piston assembly according to claim 1, characterized in that: A spherical annular groove (29) is provided in the axial direction of the roller (2), and a circular arc transition connection is formed between the groove bottom of the spherical annular groove (29) and the axial end surface of the roller (2).

4. The fuel injection pump guide piston assembly according to claim 1, characterized in that: The outer circumferential surface of the roller pin (3) is provided with a DLC coating; The roller bushing (8) is made of copper alloy.

5. The fuel injection pump guide piston assembly according to claim 1, characterized in that: The outer surface of the guide piston (1) is arranged as a cylindrical surface, and a first circumferential oil groove (20), a second circumferential oil groove (21), a first axial oil groove (23) and a vertical groove (22) are arranged on the cylindrical surface, wherein the vertical groove (22) is opened in the second circumferential oil groove (21), and the vertical groove (22) is connected to the first circumferential oil groove (20) and the second circumferential oil groove (20) through the first axial oil groove (23); An inclined hole (10) is also provided on the cylindrical surface, and two ends of the inclined hole (10) are respectively connected to the second circumferential oil groove (21) and the inner wall of the second mounting hole (16); A second axial oil groove (17) communicating with the second circumferential oil groove (21) is also provided on the cylindrical surface; A first straight hole (18) and a second straight hole (19) connected to each other are also provided on the cylindrical surface, wherein the first straight hole (18) is connected to the first axial oil groove (23), and the second straight hole (19) is connected to the first mounting hole; A lubricating oil inlet passage (9) is provided on the outer circumferential surface of the roller pin (3), the lubricating oil inlet passage (9) is arranged opposite to the inclined hole (10), and the lubricating oil inlet passage (9) is connected to the lubricating oil outlet passage.

6. The fuel injection pump guide piston assembly according to claim 1, characterized in that: A first hole (11) is provided on the hole wall of the second mounting hole (16); A second hole (26) is provided on the outer circumferential surface of the roller pin (3); A spring (4) and a stop pin (5) are placed in sequence in the second hole (26), and a portion of the stop pin (5) extends into the first hole (11).

7. The fuel injection pump guide piston assembly according to claim 1, characterized in that: Forced lubrication is adopted between the roller pin (3) and the roller bushing (8); Forced lubrication is adopted between the thrust bearing (6) and the boss (12).

8. The fuel injection pump guide piston assembly according to claim 1, characterized in that: The upper outer circumference of the guide piston (1) is provided with a first chamfer (14); A second chamfer (15) is provided on the hole wall of the first mounting hole.

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