CN116085158A

CN116085158A - Cross pin coupling device for control rod of high-pressure common rail fuel injector

Info

Publication number: CN116085158A
Application number: CN202211106084.8A
Authority: CN
Inventors: 王九如; 陈宇涵; 黄舒远
Original assignee: Putian Dexin Auto Parts Manufacturing Co ltd
Current assignee: Putian Dexin Auto Parts Manufacturing Co ltd
Priority date: 2022-09-09
Filing date: 2022-09-09
Publication date: 2023-05-09

Abstract

The invention discloses a high-pressure common rail cross pin coupling device which is used for connecting a control rod and a needle valve and eliminating faults caused by offset and non-perpendicularity between the axis of a nozzle and the axis of the control valve due to production and assembly. The high-pressure fuel oil injector fills the inner cavity A of the injector body with high-pressure fuel oil, eliminates static leakage of the injector, improves response speed of the injector and prolongs service life of the oil nozzle.

Description

Cross pin coupling device for control rod of high-pressure common rail fuel injector

Technical Field

The invention relates to a control rod cross pin coupling device of a high-pressure common rail fuel injector, belonging to the field of diesel engine fuel systems.

Background

With the implementation of five-country and six-emission regulations of diesel engine countries in China, an electric control high-pressure common rail system becomes the only choice of a diesel engine fuel system. To realize the national five-country six emission regulations, the fuel injection pressure of the diesel engine fuel system must be increased to more than 180Mpa, and some fuel injection pressures even require to be up to 200Mpa. At present, high-pressure common rail injectors of German Bosch and Japanese electric charge companies are mainly used for domestic diesel engines, and some domestic enterprises make some modifications based on the high-pressure common rail injectors and are used for common rail diesel engine hosts or accessories.

FIG. 1 is a schematic diagram of a Bosch injector structure, in which:

1. an electromagnet; 2. an armature; 3. a control valve seat; 4. a ball valve; 5. a control lever; 6. a high-pressure oil inlet; 7. a low-pressure oil return port; 9. a needle valve; 10. a nipple valve seat; 14. and (3) sealing rings.

B. A control room; A. an inner cavity; D. and an oil tank.

The high-pressure fuel oil is filled in the chambers B and D, the pressure is above 180Mpa, the pressure A is a low-pressure area, and the pressure is below 0.5Mpa, so that the high-pressure fuel oil in the region B can flow into the inner cavity A of the fuel injector through the gap between the control valve rod 5 and the control valve sleeve 3. The high-pressure fuel in the oil containing groove D area can flow into the inner cavity A of the oil injector through the clearance between the needle valve 9 and the oil nozzle valve seat 10, and the leakage amount of the two parts accounts for 15-25% of the whole leakage amount of the oil injector. The leakage of high-pressure fuel loses a large amount of hydraulic energy on the one hand, and simultaneously causes the heating temperature of the system to rise, so that the service life of the fuel injector is influenced.

In order to reduce the leakage loss of high-pressure fuel, the area A is filled with high-pressure fuel, so that B, D and the area A have no pressure difference, and the high-pressure leakage is prevented. One is to use special design, such as cummins xpi injector, see patent publication No. cn106194531.A, to integrate the control rod and needle valve, and make floating connection between the control rod and the control ball valve, to eliminate the trouble that the control rod and needle valve are blocked due to the non-concentricity and non-verticality of the control rod and the valve seat of the oil nozzle. Patent CN201110281471.0 is also of similar construction, but thus the entire fuel injector construction must be redesigned and manufactured.

A hydraulic coupling valve is arranged at the tail part of a control rod of an original common rail oil sprayer by Boshi company to form a hydraulic coupling mechanism, the control rod and an oil nozzle needle valve are not required to be integrated, and the hydraulic coupling mechanism is utilized to enable the pressure above the needle valve to drop after an electromagnet is electrified, so that the oil nozzle needle valve rises under the high-pressure action at an oil containing groove and opens oil nozzle oil injection. Such as the CN200780049995, CN2020519923 patent, but is somewhat complex in construction, with a delay of 0.1 ms for opening and closing.

The Boshi company also has products which directly integrate the needle valve and the control rod on the basis of the original common rail oil sprayer structure, such as a patent CN200880024554, but the requirements on the machining and assembling precision of the oil sprayer body and the oil nozzle parts are extremely high, the concentricity and the non-verticality are controlled between a plurality of mu, and the state of the art in China can not reach the level at present.

Disclosure of Invention

The invention aims to provide a high-pressure common rail injector control rod cross pin coupling device, which is formed by arranging a cross pin coupling between an existing common rail injector control rod 5 and a needle valve 9.

The invention aims at realizing the following steps: the control rod cross pin coupling device of the high-pressure common rail injector is a cross pin coupling 8 positioned between a control rod 5 and a needle valve 9, wherein the cross pin coupling 8 comprises a sleeve 8-2, a control rod pin 8-1, a gasket 8-3 and a needle valve pin 8-4;

wherein, a control rod pin hole 5-2 perpendicular to the axis of the control rod 5 is arranged on the control rod 5; the needle valve 9 is provided with a needle valve pin hole 9-2 perpendicular to the axis of the needle valve 9;

the lower end of the control rod 5 extends into the sleeve 8-2, the control rod pin 8-1 is positioned in the control rod pin hole 5-2, and two ends of the control rod pin 8-1 extend through the side wall of the sleeve 8-2, so that the control rod 5 is connected with the sleeve 8-2;

the upper end of the needle valve 9 extends into the sleeve 8-2, the needle valve pin 8-4 is positioned in the needle valve pin hole 9-2, and two ends of the needle valve pin 8-4 extend through the side wall of the sleeve 8-2, so that the connection between the needle valve 9 and the sleeve 8-2 is realized;

a spacer 8-3 is located within the sleeve 8-2 between the control rod 5 and the needle valve 9.

The invention has the advantages that: the cross pin coupling is arranged between the control rod and the needle valve of the conventional common rail fuel injector, so that the defect that the needle valve 5 or the control rod 9 is blocked or jammed in the movement due to the position deviation of processing or assembly and non-perpendicularity between the control rod 5 and the needle valve 9 can be eliminated.

Drawings

FIG. 1 is a schematic diagram of a conventional high pressure common rail injector from Bosch company.

Fig. 2 is a schematic view showing a structure in which a control lever and a needle valve are integrally connected.

Fig. 3 is a schematic view showing a specific structure of an oldham pin coupling according to a first embodiment of the present invention.

Fig. 4 is a detailed view of the structure of the cross pin joint sleeve.

FIG. 5 is a schematic illustration of an embodiment of a lever cross pin joint of the present invention on a common rail fuel injector.

Fig. 6 is a schematic structural view of a second embodiment of the present invention.

Fig. 7 is a schematic structural view of a third embodiment of the present invention.

Fig. 8 is a schematic structural diagram of another application mode of the present invention.

Description of the reference numerals: 1 electromagnet, 2 armature, 3 control valve seat, 3-1 oil outlet orifice, 3-2 oil inlet orifice, 4 ball valve, 5 control rod, 5-1 arc surface, 5-2 control rod pin hole, 6 high pressure oil inlet port, 7 low pressure oil return port, 8 cross pin coupling, 8-1 control rod pin, 8-2 sleeve, 8-2-1 first pin hole, 8-2-2 second pin hole, 8-3 gasket, 8-4 needle valve pin, 8-5 first limit groove, 8-6 second limit groove, 9 needle valve, 9-1 needle valve upper end, 9-2 needle valve pin hole, 10 oil nozzle valve seat, 11 return spring, 12 orifice, 13 orifice, 14 sealing ring, 15 collar, 16 gasket, 17 ring groove, 18 spring gasket, A inner cavity, B control chamber and D oil holding groove.

Detailed Description

In the description of the present invention, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "front", "rear", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of description and simplification of the description, and do not indicate or imply that the apparatus or element in question must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

The invention is described in detail below with reference to the accompanying drawings:

as shown in fig. 2, 3 and 4, the control rod cross pin coupling device of the high-pressure common rail injector is a cross pin coupling 8 between a control rod 5 and a needle valve 9, wherein the cross pin coupling 8 comprises a sleeve 8-2, a control rod pin 8-1, a gasket 8-3 and a needle valve pin 8-4;

Here the control lever 5 is integrated with the needle valve 9 by means of an oldham coupling 8.

Fig. 3 and 4 are schematic views showing the specific structure of the oldham pin coupling 8 of the present invention. The side wall of the sleeve 8-2 is provided with a first pin hole 8-2-1 and a second pin hole 8-2-2 which are perpendicular to each other respectively; the two ends of the control rod pin 8-1 pass through the first pin hole 8-2-1, and the two ends of the needle valve pin 8-4 pass through the second pin hole 8-2-2. The diameters of the first pin hole 8-2-1 and the second pin hole 8-2-2 can be the same, or can be different according to the stress condition.

The first pin hole 8-2-1 is in interference fit or movable fit with the control rod pin 8-1; the second pin hole 8-2-2 is in interference fit or movable fit with the needle valve pin 8-4.

The concrete structure is as follows: the diameter of the part of the control rod 5 extending into the sleeve 8-2 is 2.8-4 mm, the control rod pin hole 5-2 is in movable fit with the rod pin 8-1, and the outer diameter of the part of the control rod 5 extending into the sleeve 8-2 is 0.1-0.3 mm smaller than the aperture of the sleeve 8-2.

The diameter of the part of the needle valve 9 extending into the sleeve 8-2 is 3.2-4 mm, the needle valve pin hole 9-2 is in movable fit with the needle valve pin 8-4, and the outer diameter of the part of the needle valve 9 extending into the sleeve 8-2 is 0.1-0.3 mm smaller than the aperture of the sleeve 8-2. The control lever 5 is movable laterally with respect to the needle valve 9, and is rotatable about the lever pin 8-1 and the needle valve pin 8-4, with a total of 4 degrees of freedom. Because the control rod 5 and the needle valve 9 are in movable fit with the rod pin 8-1 and the needle valve pin 8-4, the control rod 5 and the needle valve 9 can freely move or rotate, and side force caused by eccentric manufacturing or assembling or non-perpendicular is eliminated, so that the control rod 5 can normally control the opening and closing of the needle valve 9.

The lower end face of the control rod 5 is an arc face 5-1. The thickness of the spacer 8-3 is required to satisfy the minimum clearance between the control rod 5, the control rod pin 8-1, the needle valve pin 8-4, and the portion of the needle valve 9 extending into the sleeve 8-2.

The side wall of the sleeve 8-2 is respectively provided with a first limit groove 8-5 and a second limit groove 8-6 which are mutually perpendicular; the width of the first limit groove 8-5 is 0.02-0.05 mm larger than the diameter of the control rod pin 8-1; the width of the second limiting groove 8-6 is 0.02-0.05 mm larger than the diameter of the needle valve pin 8-4.

The outer side wall of the sleeve (8-2) is provided with 4 flattening positions forming 45 degrees with the first pin hole 8-2-1 and the second pin hole 8-2-2, and the flattening amount b=0.1-1 mm of the flattening positions. In the case of a large demand for fuel supply, the design allows for a rapid flow of high-pressure fuel.

The structure is arranged in the high-pressure common rail fuel injector for use;

example 1

As shown in fig. 5: the high-pressure common rail oil sprayer comprises the control rod cross pin coupling device, and mainly comprises an electromagnet assembly, a control valve seat 3, an oil sprayer body and an oil nozzle valve seat 10, wherein a control rod 5 and a needle valve 9 are connected with each other and are arranged in the oil sprayer body and the oil nozzle valve seat 10, and a return spring 11 for realizing the reset of the control rod 5 is arranged in the oil sprayer body.

The side wall of the oil sprayer body is provided with an oil sprayer oil inlet 6, and the oil sprayer oil inlet 6 is communicated with an inner cavity A in the oil sprayer body; high-pressure oil enters the oil containing groove D arranged on the oil nozzle valve seat 10 through the oil nozzle orifice 13 or enters the oil containing groove D through the outer round flattening part of the needle valve 9, so that the inner cavity A is communicated with the oil containing groove D of the oil nozzle valve seat 10.

As can be seen in fig. 5, high pressure fuel from the injector inlet 6, through the orifice 12, directly into the internal cavity a in the injector body, flows through the return spring 11 and sleeve 8-2, through the orifice 13, and into the oil sump D. And accumulates at the nipple seating surface. When the electromagnet 1 is electrified, the armature 2 is sucked up, the ball valve 4 is opened, high-pressure fuel in the control chamber B flows to the low-pressure cavity through the oil outlet throttle hole 3-1, the high-pressure fuel flowing into the control chamber B is less than the high-pressure fuel flowing out because the diameter of the oil inlet throttle hole 3-2 is smaller than that of the oil outlet throttle hole 3-1, the high-pressure fuel pressure in the control chamber B is reduced, the control rod 5 is pushed upwards by the high-pressure fuel in the inner cavity A, when the fuel pressure in the control chamber B is smaller than the sum of the maximum hydraulic pressure acting on the control rod 5 and the spring pretightening force, the control rod 5 pulls the control rod pin 8-1, and the sleeve 8-2 and the needle valve pin 8-4 pull the needle valve 9 to rise, so that the oil nozzle sprays oil.

When the electromagnet 1 is powered off, the ball valve 4 falls on the conical surface of the control valve seat 3, and the oil outlet orifice 3-1 is closed to flow to a low-pressure channel. The high-pressure fuel continuously flows into the control chamber B from the oil inlet orifice 3-2, so that the fuel pressure of the control chamber B is increased, when the fuel pressure of the control chamber B acts on the control rod 5 and the elastic force of the return spring 11 exceeds the upward pressure acting on the control rod 5, the control rod 5 moves downwards, and the arc surface 5-1 of the control rod presses the gasket 8-3 and the needle valve 9. When the fuel pressure in the control chamber B and the elastic force of the return spring 11 exceed the hydraulic pressure acting on the needle valve 9 and the control lever 5 upward, the tapered surface of the needle valve 9 is dropped onto the tapered surface of the nozzle valve seat 10, and the nozzle is closed to stop the injection.

In order to minimize the accumulation of clearances in the upper end faces of the control rod pin 8-1, the needle valve pin 8-4, the control rod 5, and the needle valve 9 in the sleeve 8-2, the thickness of the spacer 8-3 may be appropriately selected, thereby increasing the response speed.

The diameter of the control rod is 2.8-4 mm, the diameters of the 8-1 control rod pin and the 8-4 needle valve pin are 1.2-2.7 mm, and the diameter of the 9-1 part of the needle valve is 2.8-4 mm, so that the control rod is preferentially selected under the condition of ensuring the strength of the part according to the oil injection pressure.

According to preliminary calculation, when the fuel pressure is 180Mpa, the pretightening force of the return spring 11 is about 0.4Mpa, the force acting on the valve seat of the nozzle tip of the existing Bosch structure fuel injector is about 1274N, and the acting force of the cross pin coupling structure is 922N. Meanwhile, when the pressure in the control chamber B is in the structure of the existing fuel injector, the fuel nozzle can be opened only when the pressure is reduced to 92Mpa, and after the cross pin coupling is adopted, the fuel pressure in the chamber B is reduced to 121Mpa, so that the fuel nozzle can be opened.

After the cross pin coupling 8 is adopted, the hydraulic pressure of the oil nozzle seat surface can be reduced, the service life of the oil nozzle can be prolonged, and meanwhile, the opening delay of the oil nozzle can be reduced, and the response is faster.

Preliminary experiments also prove that under the condition of 120Mpa of oil injection pressure, the oil supply quantity is 500mg, the oil supply duration of the oil injector with the old Bosch structure is 900 microseconds, and the oil supply duration is reduced to 600 microseconds after the cross pin coupling 8 is adopted. Meanwhile, the oil supply variance is smaller, which indicates that the cross pin floating coupling 8 is adopted, and the lateral force on the nozzle needle valve 9 and the control rod 5 caused by the non-concentricity is small.

Example 2

As shown in fig. 6, the position of the return spring 11 is adjusted on the basis of embodiment 1; a clamping ring 15 and a gasket 16 are arranged on the upper part of the control rod 5 in a ring manner, and a spring gasket 18 is arranged on the bottom surface of the control valve seat 3; the return spring 11 is located between a washer 16 and a spring washer 18. In order to secure the collar 15 and the washer 16, it is necessary to provide the lever 5 with a ring groove 17, the collar 15 and the washer 16 are fitted into the ring groove 17, the lower end of the return spring 11 is pressed against the washer 16, and the upper end thereof is pressed against the lower end face of the control valve seat 3 via a spring washer 18. The advantage is that the pressure of the return spring 11 directly presses the needle valve 9 through the control rod 5 and the spacer 8-3 without acting on the control rod pin 8-1 and the needle valve pin 8-4 through the sleeve 8-2, reducing the shear stress of the control rod pin 8-1 and the needle valve pin 8-4. Meanwhile, the control rod 5, the cross pin coupling 8 and the nozzle needle valve 9 can be assembled into parts in advance, and the parts are directly assembled into the nozzle valve seat 10 from top to bottom during assembly.

Example 3

As shown in fig. 7 and 8, in this embodiment, the first pin hole 8-2-1 and the second pin hole 8-2-2 of the box 8-2 are adjusted based on the embodiment 1. Specifically, a first limit groove 8-5 and a second limit groove 8-6 which are mutually perpendicular are respectively formed in the side wall of the sleeve 8-2; the width of the first limit groove 8-5 is 0.02-0.05 mm larger than the diameter of the control rod pin 8-1; the width of the second limiting groove 8-6 is 0.02-0.05 mm larger than the diameter of the needle valve pin 8-4.

In addition, the outer side wall of the sleeve 8-2 is provided with 4 flattening positions forming 45 degrees with the first pin hole 8-2-1 and the second pin hole 8-2-2, and the flattening amount b=0.1-1 mm of the flattening positions. In the case of a large demand for fuel supply, the design allows for a rapid flow of high-pressure fuel.

In the embodiment, the control rod pin 8-1 and the needle valve pin 8-4 can move and rotate freely in the first limit groove 8-5 and the second limit groove 8-6 respectively, so that the influence of axial eccentricity and non-perpendicularity of the control rod 5 and the needle valve 9 is eliminated, and the quick opening and closing of the oil nozzle are ensured.

In fig. 8, in order to make high-pressure fuel not need to enter the oil containing groove D through the throttle hole 13 and the oil inlet hole of the oil nozzle, so that the sealing of the end face of the oil injector and the end face of the oil nozzle is facilitated, 4 flattening positions forming 45 degrees with the first pin hole 8-2-1 and the second pin hole 8-2-2 are arranged on the outer side wall of the sleeve 8-2, and the flattening amount b=0.1-1 mm of the flattening positions. After the flattening position is kept, the outer circular arc of the sleeve 8-2 is used for ensuring the concentricity of the conical surface of the needle valve 9 and the conical surface of the nozzle valve seat 10 and ensuring the tightness of the conical surface of the nozzle.

The invention can be used on most common rail fuel injectors of companies like Bosch and electric appliances, etc., which are commonly used at present, reduces leakage, improves the quick response performance of the common rail fuel injector, reaches the national six-emission standard of diesel engines, and prolongs the service life of the common rail fuel injector.

It should be noted that the foregoing description is only a preferred embodiment of the present invention, and although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood that modifications, equivalents, improvements and modifications to the technical solution described in the foregoing embodiments may occur to those skilled in the art, and all modifications, equivalents, and improvements are intended to be included within the spirit and principle of the present invention.

Claims

1. The utility model provides a high pressure common rail fuel injector control rod cross pin shaft coupling device which characterized in that: the device is an Oldham pin coupling (8) positioned between a control rod (5) and a needle valve (9), wherein the Oldham pin coupling (8) comprises a sleeve (8-2), a control rod pin (8-1), a gasket (8-3) and a needle valve pin (8-4);

wherein, a control rod pin hole (5-2) perpendicular to the axis of the control rod (5) is arranged on the control rod (5); a needle valve pin hole (9-2) perpendicular to the axis of the needle valve (9) is formed in the needle valve (9);

the lower end of the control rod (5) extends into the sleeve (8-2), the control rod pin (8-1) is positioned in the control rod pin hole (5-2), and two ends of the control rod pin (8-1) extend through the side wall of the sleeve (8-2), so that the connection between the control rod (5) and the sleeve (8-2) is realized;

the upper end of the needle valve (9) stretches into the sleeve (8-2), the needle valve pin (8-4) is positioned in the needle valve pin hole (9-2), and two ends of the needle valve pin (8-4) extend through the side wall of the sleeve (8-2), so that the needle valve (9) is connected with the sleeve (8-2);

the gasket (8-3) is positioned in the sleeve (8-2) between the control rod (5) and the needle valve (9).

2. A high pressure common rail injector control rod cross pin coupling device as defined in claim 1, wherein: the side wall of the sleeve (8-2) is provided with a first pin hole (8-2-1) and a second pin hole (8-2-2) which are perpendicular to each other respectively; the two ends of the control rod pin (8-1) pass through the first pin hole (8-2-1), and the two ends of the needle valve pin (8-4) pass through the second pin hole (8-2-2).

3. A high pressure common rail injector control rod cross pin coupling device as claimed in claim 2, wherein:

the first pin hole (8-2-1) is in interference fit or movable fit with the control rod pin (8-1); the second pin hole (8-2-2) is in interference fit or movable fit with the needle valve pin (8-4).

4. A high pressure common rail injector control rod cross pin coupling device as defined in claim 1, wherein:

the diameter of the part of the control rod (5) extending into the sleeve (8-2) is 2.8-4 mm, the control rod pin hole (5-2) is in movable fit with the control rod pin (8-1), and the outer diameter of the part of the control rod (5) extending into the sleeve (8-2) is 0.1-0.3 mm smaller than the aperture of the sleeve (8-2).

5. A high pressure common rail injector control rod cross pin coupling device as defined in claim 1, wherein:

the diameter of the part of the needle valve (9) extending into the sleeve (8-2) is 3.2-4 mm, the needle valve pin hole (9-2) is in movable fit with the needle valve pin (8-4), and the outer diameter of the part of the needle valve (9) extending into the sleeve (8-2) is 0.1-0.3 mm smaller than the aperture of the sleeve (8-2).

6. A high pressure common rail injector control rod cross pin coupling device as defined in claim 1, wherein:

the side wall of the sleeve (8-2) is respectively provided with a first limit groove (8-5) and a second limit groove (8-6) which are mutually perpendicular; the width of the first limit groove (8-5) is 0.02-0.05 mm larger than the diameter of the control rod pin (8-1); the width of the second limit groove (8-6) is 0.02-0.05 mm larger than the diameter of the needle valve pin (8-4).

7. A high pressure common rail injector control rod cross pin coupling device as defined in claim 1, wherein: the lower end surface of the control rod (5) is an arc surface (5-1); the thickness of the gasket (8-3) is required to meet the requirement that the clearance between the control rod (5), the control rod pin (8-1), the needle valve pin (8-4) and the part of the needle valve (9) extending into the sleeve (8-2) is minimum.

8. A high pressure common rail injector control rod cross pin coupling device as defined in claim 1, wherein: the outer side wall of the sleeve (8-2) is provided with 4 flattening positions which form 45 degrees with the first pin hole (8-2-1) and the second pin hole (8-2-2), and the flattening amount b=0.1-1 mm of the flattening positions.

9. The high-pressure common rail oil sprayer is characterized by comprising the control rod cross pin coupling device disclosed in the claims 1-8, and mainly comprising an electromagnet assembly, a control valve seat (3), an oil sprayer body and an oil nozzle valve seat (10), wherein the control rod (5) and the needle valve (9) are connected with each other and are arranged in the oil sprayer body and the oil nozzle valve seat (10), and a return spring (11) for realizing the return of the control rod (5) is arranged in the oil sprayer body;

the side wall of the oil sprayer body is provided with an oil inlet hole (6) of the oil sprayer, and the oil inlet hole (6) of the oil sprayer is communicated with an inner cavity (A) in the oil sprayer body; high-pressure oil enters an oil containing groove D arranged on a nozzle valve seat (10) through a nozzle orifice (13), or enters the oil containing groove D through an outer round flattening part of a needle valve (9), so that the inner cavity (A) is communicated with the oil containing groove D of the nozzle valve seat (10).

10. The high pressure common rail injector of claim 9, wherein: a clamping ring (15) and a gasket (16) are arranged on the upper part of the control rod (5) in a ring way, and a spring gasket (18) is arranged on the bottom surface of the control valve seat (3); the return spring (11) is located between the washer (16) and the spring washer (18).