High-precision wedge-shaped metering oil needle and machining method thereof

Abstract

The invention belongs to the field of aero-engine fuel oil control systems, and relates to a high-precision wedge-shaped metering oil needle and a machining method thereof. The invention provides a high-precision wedge-shaped metering oil needle. The high-precision wedge-shaped metering oil needle comprises a metering oil needle body (1), a metering valve bush (2) and a guide device (3). The metering oil needle (1) penetrates through the guide device (3), the tapered front end of the metering oil needle (1) is inserted into a fuel oil circulation window of the metering valve lining (2), the metering oil needle (1) can move in the axial direction, so that the area of the fuel oil circulation window is changed, and the front end of the metering oil needle (1) is a wedge-shaped surface. The method can be widely applied to the fields of automobiles, ships, aviation, spaceflight and the like.

Description

Technical Field

[0001] The invention belongs to the field of aviation engine fuel control systems and relates to a high-precision wedge-shaped metering oil needle and a processing method thereof. Background Art

[0002] like Figure 1 As shown, the fuel flow window of the metering needle assembly under the traditional structure is annular, such as Figure 3 As shown, the length / gap is relatively large. The working environment of aircraft engines is complex, especially under low-temperature conditions with small flow rates, the fuel viscosity is high, the gap of the annular flow window is narrow, and the high-viscosity fuel is not easy to flow in the window, which can easily clog the window, and the "temperature-fuel flow" characteristics of the fuel control system are poor. Summary of the invention

[0003] The purpose of the present invention is to provide a high-precision wedge-shaped metering oil needle and a processing method thereof, and to propose a structural design scheme for a high-precision wedge-shaped metering oil needle with feasible process, good consistency and high safety factor, which can be used for mass production.

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

[0005] A high-precision wedge-shaped metering oil needle, comprising:

[0006] Metering oil needle 1, metering valve bushing 2, and guide device 3;

[0007] The metering needle 1 passes through the guide device 3, and the tapered front end of the metering needle 1 is inserted into the fuel flow window of the metering valve bushing 2, and the metering needle 1 can move axially, thereby changing the area of ​​the fuel flow window.

[0008] The characteristic is that the front end of the metering oil needle 1 is a wedge-shaped surface.

[0009] include:

[0010] The wedge-shaped surface at the front end of the metering oil needle 1 is achieved by obliquely cutting the front end of the metering oil needle 1 from top to bottom.

[0011] The material of the metering oil needle 1 is steel.

[0012] The metering valve bushing 2 and the guide device 3 are made of aluminum.

[0013] A high-precision wedge-shaped metering oil needle processing method is provided, wherein the front end of the metering oil needle 1 is obliquely cut from top to bottom to form a wedge-shaped surface at the front end of the metering oil needle 1.

[0014] include:

[0015] Step 1: Use a CNC lathe turning method, apply a process lengthening method, clamp the outer circle of the metering oil needle, and position the end of the metering oil needle to machine the metering oil needle shape;

[0016] Step 2: Use the slow wire cutting processing method to clamp the outer circle of the oil needle guide, and process the wedge-shaped surface of the metering oil needle by reserving a 0.25mm margin;

[0017] Step 3: Use high-precision CNC external cylindrical grinding to position the guide outer circle and flow control outer circle by top alignment to complete the finishing process;

[0018] Step 4: Use slow wire cutting to clamp the oil needle 1 to guide the outer circle, lengthen the cutting process, and process the wedge-shaped surface of the metering oil needle.

[0019] Also includes:

[0020] Step 5: Check the dimensions of each point on the profile to see if they meet the final requirements of the design drawing; check the roughness of each surface to see if it meets the requirements of the design drawing; check the runout of the outer circle of the profile to the guide outer circle to see if it meets the requirements of the design drawing.

[0021] Step 5 also includes: checking whether each point of the profile is smoothly connected and whether there are no visible bosses or depressions.

[0022] The advantages of the present invention are:

[0023] 1. The number and size of the metering needle surface can be designed and processed as needed, which can accurately adjust the fuel supply and has good low-temperature characteristics.

[0024] 2. The cylindrical surface of the metering oil needle is formed by a high-precision CNC cylindrical grinder, and the inclined surface is formed by a high-precision CNC wire cutting machine, with a stable structure and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the structure of a conical metering oil needle;

[0026] Figure 2 It is a schematic diagram of the conical metering oil needle profile;

[0027] Figure 3 It is the circulation diagram of the conical metering oil needle;

[0028] Figure 4 This is a schematic diagram of the wedge-shaped metering oil needle structure;

[0029] Figure 5 It is a schematic diagram of the profile of a wedge-shaped metering oil needle;

[0030] Figure 6 It is the circulation diagram of the wedge-shaped metering oil needle;

[0031] Figure 7 This is a schematic diagram of the simulation of the deformation of the top clamp of the wedge-shaped metering oil needle;

[0032] Figure 8 It is a simulation diagram of a wedge-shaped metering oil needle flow plant;

[0033] Fig. 9 It is a graph showing the relationship between volume flow and displacement of a wedge-shaped metering needle assembly. DETAILED DESCRIPTION

[0034] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0035] The present invention utilizes the principle of small hole throttling, improves the surface structure of the metering oil needle, and uses a beveled metering oil needle to replace the traditional conical metering oil needle. Figure 4-6 As shown, a high-precision wedge-shaped metering oil needle comprises:

[0036] Metering oil needle 1, metering valve bushing 2, and guide device 3;

[0037] The metering needle 1 passes through the guide device 3, and the tapered front end of the metering needle 1 is inserted into the fuel flow window of the metering valve bushing 2, and the metering needle 1 can move axially, thereby changing the area of ​​the fuel flow window.

[0038] The front end of the metering oil needle 1 is a wedge-shaped surface.

[0039] include:

[0040] The wedge-shaped surface at the front end of the metering oil needle 1 is achieved by obliquely cutting the front end of the metering oil needle 1 from top to bottom.

[0041] The material of the metering oil needle 1 is steel.

[0042] The metering valve bushing 2 and the guide device 3 are made of aluminum.

[0043] When designing the wedge-shaped metering needle, the fuel regulation performance, stability and low-temperature characteristics of the metering needle were fully considered, and the process feasibility of the metering needle was paid attention to. With reasonable process parameters, a high-precision wedge-shaped metering needle with simple and efficient process technology was proposed. This structure makes full use of the throttling effect of the small hole, improves the length / gap ratio of the product in the small flow state, reduces the influence of viscosity on the flow of fuel under low temperature conditions, significantly improves the low-temperature characteristics of the regulator, and improves the "temperature-fuel flow" characteristics of the main control metering unit.

[0044] A high-precision wedge-shaped metering oil needle processing method is provided, wherein the front end of the metering oil needle 1 is obliquely cut from top to bottom to form a wedge-shaped surface at the front end of the metering oil needle 1.

[0045] include:

[0046] Step 1: Use a CNC lathe turning method, apply a process lengthening method, clamp the outer circle of the metering oil needle, and position the end of the metering oil needle to machine the metering oil needle shape;

[0047] Step 2: Use the slow wire cutting processing method to clamp the outer circle of the oil needle guide, and process the wedge-shaped surface of the metering oil needle by reserving a 0.25mm margin;

[0048] Step 3: Use high-precision CNC external cylindrical grinding to position the parts by means of top-to-top, and complete the finishing of the guide outer circle and flow control outer circle. During the process, the clamping force of the machine tool top is determined by simulation to prevent the parts from being deformed by the top-to-top force and affecting their processing quality. Fig. 9 As shown;

[0049] Step 4: Use a slow wire cutting process to clamp the oil needle (1) to guide the outer circle, lengthen the cutting process, and process a wedge-shaped surface of the metering oil needle.

[0050] Also includes:

[0051] Step 5: Check the dimensions of each point on the profile to see if they meet the final requirements of the design drawing; check the roughness of each surface to see if it meets the requirements of the design drawing; check the runout of the outer circle of the profile to the guide outer circle to see if it meets the requirements of the design drawing.

[0052] Step 5 also includes: checking whether each point of the profile is smoothly connected and whether there are no visible bosses or depressions.

[0053] The fuel flow window of the metering needle assembly under the traditional structure is annular, such as Figure 1-3 As shown, the length / gap is relatively large. The working environment of aircraft engines is complex, especially at low temperatures, the fuel viscosity is high, and the "temperature-fuel flow" characteristics of the fuel control system are poor. The high-precision wedge-shaped metering oil needle proposed in the present invention has a hole-shaped fuel flow window, such as Figure 6 As shown in the figure, the length / gap ratio of the product at low flow is improved, ensuring that the working state of the metering valve is closer to the small hole throttling at low flow, making the fuel flow under low temperature conditions less affected by viscosity, significantly improving the low temperature characteristics, and improving the "temperature-fuel flow" characteristics of the main control metering unit. After the metering needle structure is changed, in order to ensure the linear change and high precision requirements of the metered fuel, the fluid simulation software is used for modeling and analysis, see Figure 7 , find out the relationship between flow and displacement, and complete the design parameters of the metering oil needle surface, see Figure 8 . Through continuous iteration and optimization of experiments, the design of the beveled metering oil needle was finally completed.

Claims

1. A high-precision wedge-shaped metering oil needle, comprising: Metering oil needle (1), metering valve bushing (2), and guide device (3); The metering needle (1) passes through the guide device (3), and the tapered front end of the metering needle (1) is inserted into the fuel flow window of the metering valve bushing (2), and the metering needle (1) can move in the axial direction, thereby changing the area of ​​the fuel flow window. The invention is characterized in that the front end of the metering oil needle (1) is a wedge-shaped surface.

2. A high-precision wedge-shaped metering oil needle as claimed in claim 1, characterized in that: include: The wedge-shaped surface at the front end of the metering oil needle (1) is achieved by making an oblique cut from top to bottom on the front end of the metering oil needle (1).

3. A high-precision wedge-shaped metering oil needle as claimed in claim 1, characterized in that: The material of the metering needle (1) is steel.

4. A high-precision wedge-shaped metering oil needle as claimed in claim 1, characterized in that: The metering valve bushing (2) and the guide device (3) are made of aluminum.

5. A high-precision wedge-shaped metering oil needle processing method, characterized in that: The front end of the metering oil needle (1) is cut obliquely from top to bottom to form a wedge-shaped surface at the front end of the metering oil needle (1).

6. A high-precision wedge-shaped metering oil needle machining method as claimed in claim 5, characterized in that: include: Step 1: Use a CNC lathe turning method, apply a process lengthening method, clamp the outer circle of the metering oil needle, and position the end of the metering oil needle to machine the metering oil needle shape; Step 2: Use the slow wire cutting processing method to clamp the outer circle of the oil needle guide, and process the wedge-shaped surface of the metering oil needle by reserving a 0.25mm margin; Step 3: Use high-precision CNC external cylindrical grinding to position the guide outer circle and flow control outer circle by top alignment to complete the finishing process; Step 4: Use a slow wire cutting process to clamp the oil needle (1) to guide the outer circle, lengthen the cutting process, and process a wedge-shaped surface of the metering oil needle.

7. A high-precision wedge-shaped metering oil needle machining method as claimed in claim 6, characterized in that: Also includes: Step 5: Check the dimensions of each point on the profile to see if they meet the final requirements of the design drawing; check the roughness of each surface to see if it meets the requirements of the design drawing; check the runout of the outer circle of the profile to the guide outer circle to see if it meets the requirements of the design drawing.

8. A high-precision wedge-shaped metering oil needle machining method as claimed in claim 7, characterized in that: Step 5 also includes: checking whether each point of the profile is smoothly connected and whether there are no visible bosses or depressions.

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