Sealing structure of oil injection needle valve and oil injection nozzle cavity

Abstract

The utility model provides a sealing structure of an oil injection needle valve and an oil injection nozzle cavity, which improves the original surface sealing into linear sealing, increases the sealing pressure, ensures the sealing reliability and reduces the processing difficulty. The oil injection needle valve comprises a guide section and a needle valve section, and a needle valve head is arranged at the bottom of the needle valve; an oil guide cavity, a conical closing cavity and an oil spraying cavity are formed in the oil spraying nozzle; the conical closing cavity is a conical surface with the closing angle of alpha degrees inwards from top to bottom, the needle valve head comprises a first conical surface with the closing angle of beta degrees and a second conical surface with the closing angle of gamma degrees corresponding to the conical closing cavity, values of alpha, beta and gamma are angulation values corresponding to the vertical middle vertical plane, beta is smaller than alpha, gamma is larger than alpha, and the first conical surface is a conical surface with the closing angle of alpha degrees. And the first conical surface and the second conical surface are combined to form a circular ring line for sealing the conical closing cavity.

Description

Technical Field

[0001] This utility model relates to the technical field of electric fuel injector structure, specifically a sealing structure for a fuel injection needle valve and a fuel injector cavity. Background Technology

[0002] The high-pressure common rail electric fuel injection system controls the opening and closing of the injection needle valve within the injector cavity via a solenoid valve. During closure, the high-pressure fuel pressure within the entire injector cavity remains constant, thus placing extremely high sealing requirements on the mating surfaces of the injection needle valve and the injector cavity. Existing seals for the injection needle valve and injector cavity are conical seals, achieved by setting a conical surface at the end of the injection needle valve with the same angle as the injector cavity. However, this integral conical seal places high demands on the machining of the injection needle tip; even a slight angular deviation can compromise the seal. Furthermore, existing conical seals, due to their relatively large contact area, result in relatively low sealing pressure under high pressure conditions. Therefore, there is an urgent need to develop a sealing structure for the injection needle valve and injector cavity that is easier to manufacture and provides a more reliable seal. Utility Model Content

[0003] To address the aforementioned issues, this invention provides a sealing structure for the injection needle valve and the injection nozzle cavity, which improves the original surface seal to a line seal, increasing the sealing pressure, ensuring sealing reliability, and reducing processing difficulty.

[0004] A sealing structure for a fuel injection needle valve and a fuel injector cavity, characterized in that it comprises:

[0005] The fuel injection needle valve includes a guide section and a needle valve section, and a needle valve head is provided at the bottom of the needle valve;

[0006] And the fuel injector, which is equipped with an oil guide chamber, a conical constriction chamber and an injection chamber;

[0007] The conical constriction cavity is a conical surface with an inward constriction angle of α° from top to bottom. The needle valve head, corresponding to the conical constriction cavity, includes a first conical surface with a constriction angle of β° and a second conical surface with a constriction angle of γ°, where β is less than α and γ is greater than α. The first and second conical surfaces combine to form a circular line for sealing the conical constriction cavity.

[0008] Its further features are:

[0009] The bottom of the second conical surface is located inside the oil injection chamber. A pressure head is provided below the second conical surface. The pressure head is a cone with a flat bottom. The outer periphery of the cone is a third conical surface that tapers from top to bottom. The taper angle of the third conical surface from top to bottom is δ°, where δ is greater than γ.

[0010] Preferably, α-β = 0.5, γ-α = 0.5;

[0011] In the sealed state, the height of the annular line is located at one-third of the height of the conical constricting cavity from bottom to top. This ensures that the oil in the oil guide cavity and the oil in the upper layer of the conical constricting cavity have sufficient pressure to act on the annular line, ensuring a high oil pressure state for sealing.

[0012] By adopting this utility model, the original conical surface integral seal is transformed into a circular line seal. Compared to surface seals, which experience surface wear after a period of use, resulting in a deterioration in sealing performance, the angle formed by the circular line corresponding to the line seal gradually transitions from a line seal state to a surface seal state even as it is continuously smoothed during use. This allows the seal to be maintained for a longer period. Furthermore, the improved structure of the injection needle valve eliminates the need for complex machining; only the tool path needs to be modified, reducing machining difficulty. In addition, by transforming the surface seal into a line seal, the sealing pressure is increased when the upper oil level is almost the same. Thus, by improving the original surface seal into a line seal, the sealing pressure is increased, ensuring sealing reliability and reducing machining difficulty. Attached Figure Description

[0013] Figure 1 This is the main view assembly diagram of this utility model;

[0014] Figure 2 This is a cross-sectional view of the present invention;

[0015] Figure 3 for Figure 2 A magnified schematic diagram of the structure at point A (the angle of the bend in the diagram has been enlarged).

[0016] The names corresponding to the serial numbers in the diagram are as follows:

[0017] 10. Injection needle valve, 11. Guide section, 12. Needle valve section, 13. Needle valve head, 131. First cone surface, 132. Second cone surface, 133. Circular line, 134. Third cone surface, 20. Injector nozzle, 21. Guide chamber, 22. Conical constriction chamber, 23. Injection chamber. Detailed Implementation

[0018] A sealing structure for the injection needle valve and the injector nozzle cavity, see Figures 1-3 It includes a fuel injection needle valve 10 and a fuel injector 20;

[0019] The fuel injection needle valve 10 includes a guide section 11 and a needle valve section 12, and a needle valve head 13 is provided at the bottom of the needle valve 12; the fuel injector 20 is provided with an oil guide chamber 21, a conical constriction chamber 22, and an injection chamber 23.

[0020] The conical constriction cavity 22 is a conical surface with an inward closing angle of α° from top to bottom. The needle valve head 13 corresponds to the conical constriction cavity 22 and includes a first conical surface 131 with a closing angle of β° and a second conical surface 132 with a closing angle of γ°. β is less than α and γ is greater than α. The first conical surface 131 and the second conical surface 132 are combined to form a circular line 133 formed by a bend connection, which is used to seal the conical constriction cavity.

[0021] The bottom of the second conical surface 132 is located inside the oil injection chamber 23. A pressure head is provided below the second conical surface 132. The pressure head is a cone with a flat bottom. The outer periphery of the cone is a third conical surface 134 that tapers from top to bottom. The taper angle of the third conical surface 134 from top to bottom is δ°, where δ is greater than γ.

[0022] In the sealed state, the height of the annular line 133 is located at one-third of the height of the conical constricting cavity 22 from bottom to top. This ensures that the oil in the oil guide cavity 21 and the oil in the upper part of the conical constricting cavity 22 have sufficient pressure to act on the annular line 133, ensuring a high oil pressure state for sealing.

[0023] Its working principle is as follows: The original conical surface seal is transformed into a circular line seal. Compared to a surface seal, which will wear down after a period of use, thus reducing the sealing effect, the bend formed by the circular line corresponding to the line seal gradually transforms from a line seal state to a surface seal state even as it is continuously worn down during use. This allows the seal to be maintained for a longer period of time. In addition, the improved structure of the injection needle valve requires no complex machining; only the tool path needs to be changed, reducing the machining difficulty. Furthermore, by transforming the surface seal into a line seal, the sealing pressure is increased when the upper oil level is almost the same. Thus, the improvement from a surface seal to a line seal increases the sealing pressure, ensures sealing reliability, and reduces machining difficulty.

[0024] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0025] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A sealing structure for a fuel injection needle valve and a fuel injector cavity, characterized in that, It includes: The fuel injection needle valve includes a guide section and a needle valve section, and a needle valve head is provided at the bottom of the needle valve; And the fuel injector, which is equipped with an oil guide chamber, a conical constriction chamber and an injection chamber; The conical constriction cavity is a conical surface with an inward constriction angle of α° from top to bottom. The needle valve head, corresponding to the conical constriction cavity, includes a first conical surface with a constriction angle of β° and a second conical surface with a constriction angle of γ°, where β is less than α and γ is greater than α. The first and second conical surfaces combine to form a circular line for sealing the conical constriction cavity.

2. The sealing structure of the injection needle valve and the injection nozzle cavity according to claim 1, characterized in that: The bottom of the second conical surface is located inside the oil injection chamber. A pressure head is provided below the second conical surface. The pressure head is a cone with a flat bottom. The outer periphery of the cone is a third conical surface that tapers from top to bottom. The taper angle of the third conical surface from top to bottom is δ°, where δ is greater than γ.

3. The sealing structure of the injection needle valve and the injection nozzle cavity according to claim 1, characterized in that: Said α-β=0.5, γ-α=0.

5.

4. The sealing structure of the injection needle valve and the injection nozzle cavity according to claim 1, characterized in that: In the sealed state, the height of the annular line is located at one-third of the height of the conical constricting cavity from bottom to top.

Images