Structure of forged oil rail and manufacturing method thereof

Abstract

The invention relates to a structure of a forged oil rail and a manufacturing method thereof. The structure of the forged oil rail is provided with a plurality of pressure-bearing seats; the main body of the forged oil rail is assembled with the pressure-bearing seat, and the main body of the forged oil rail is tightly connected with the pressure-bearing seat in a brazing manner. The forging oil rail has the advantages of being simple in structure, high in cost performance, good in reliability and the like, and the problem that the forging oil rail body is torn when fluid stress exceeds the yield strength of material base metal is completely solved.

Description

Technical Field

[0001] This invention relates to hydraulic rails and their manufacturing methods, particularly to a forged hydraulic rail structure and its manufacturing method. Background Technology

[0002] Currently, in the gasoline rail manufacturing process, with increasingly stringent emission standards, the required injection pressure is also increasing. To meet these emission requirements, the fuel rail design has shifted from assembled brazed rails to integral forged rails, requiring CNC machining equipment to manufacture the forged rails. Faced with ever-increasing injection pressures, the inherent stress imbalances within the product are becoming increasingly prominent.

[0003] Please see Figure 1-3 These are CAE analyses of the stress levels in existing forging hydraulic rails. Figure 1 , 2 The analysis leads to the following conclusions: When the diameter of the main oil passage is fixed, the larger the diameter of the radial flow channel, the smaller the axial stress, and under the same material conditions, the less prone it is to tearing of the base material. Stress concentration occurs at the inlet of the radial flow channel. Through analysis of... Figure 2 , 3 Based on the analysis, the following conclusions can be drawn: When the diameter of the radial flow channel is fixed, the smaller the diameter of the main oil passage, the smaller the axial stress, and the less likely the base material will tear, assuming the same material. Stress concentration occurs at the inlet of the radial flow channel.

[0004] However, the radial flow channel, often defined by the customer's design boundary, not only serves as a flow channel but also acts as a constraint for the installation and fixation of injectors or support blocks. Therefore, the diameter of the radial flow channel cannot be expanded indefinitely. Furthermore, the design of the main oil passage, which affects the pressure fluctuations of the entire system, also limits its diameter from being too small. Consequently, when the fluid stress exceeds the yield strength of the base material, the tearing of the forged oil rail body becomes inevitable.

[0005] In summary, based on the CAE analysis results, the following conclusions can be drawn: Within the limits of the design boundaries, a smaller main oil passage design diameter and a larger diameter for the branch channels result in lower stress pressure and improved stress concentration. Stress concentration occurs at the inlet of the radial branch channels. Summary of the Invention

[0006] The purpose of this invention is to provide a structure for a forged oil rail and its manufacturing method, which mainly solves the technical problems existing in the prior art. This invention has the advantages of simple structure, high cost performance and good reliability, and completely overcomes the problem that the forged oil rail body is torn when the fluid stress exceeds the yield strength of the base material.

[0007] To solve the above-mentioned technical problems, the present invention is implemented as follows:

[0008] A forged oil rail structure is characterized by: having a plurality of pressure-bearing seats; the main body of the forged oil rail and the pressure-bearing seats are assembled by brazing to tightly connect the main body of the forged oil rail and the pressure-bearing seats.

[0009] The forged oil rail is characterized in that the assembly and positioning method between the main body of the forged oil rail and the pressure seat is press-fit positioning or laser welding spot welding positioning.

[0010] The forged oil rail is characterized in that: the pressure bearing seat is brazed by plating copper on its surface to connect the pressure bearing seat to the main body of the forged oil rail.

[0011] The structure of the forged oil rail is characterized by the following: In terms of the material selection of the pressure bearing seat, due to the mechanical properties of the material, the crystal lattice changes, and after brazing, the material itself will return to the original mechanical properties of the parent material; the pressure bearing seat uses a material with a higher yield strength than the main body of the forged oil rail, so as to resist higher stress pressure and achieve the reliability and durability of the design.

[0012] The forged oil rail structure is characterized by the following: the pressure bearing seat adopts a stepped segmented pressure bearing structure, with the lower part of the structure being larger than the upper part, and the side closer to the main oil passage being larger.

[0013] A method for manufacturing the forged oil rail structure as described above is characterized in that: a pressure seat is pre-positioned on a tooling, a dummy is used for initial positioning and alignment, a vacuum method is used to adsorb the pressure seat, and the forged oil rail is fixed on the tooling at the same time. The clamping mechanism is activated, and the oil cylinder clamps the oil rail. After activation, the pressure seat is pressed into the oil passage hole of the forged oil rail.

[0014] The manufacturing method of the forged oil rail structure is characterized in that: the method further includes brazing by plating copper on the surface of the pressure seat to connect the pressure seat to the main body of the forged oil rail.

[0015] The beneficial effects of this invention are:

[0016] 1. The structure of the forged oil rail of the present invention solves the problem that existing designs are often limited by design boundaries and cannot optimize the stress intensity to be lower than the yield strength of the base material by assembling a pressure bearing seat on the main body of the forged oil rail.

[0017] 2. Since the gap between the main body of the forged oil rail and the pressure seat is very small and the position is quite demanding, it is not possible to use copper rings, copper paste / flux, etc. The present invention uses copper plating on the surface of the pressure seat for brazing to connect the pressure seat and the main body of the forged oil rail.

[0018] 3. In this invention, regarding the material selection for the pressure bearing seat, due to the mechanical properties of the material, the crystal lattice changes. After brazing, the material itself will revert to the original mechanical properties of the parent material. Therefore, this design uses a material with higher yield strength for the pressure bearing seat to withstand higher stress pressure, thereby achieving the reliability and durability of the design.

[0019] 4. In the structural design of the pressure bearing seat of this invention, due to design limitations, a stepped segmented pressure bearing structure is adopted. The structure is larger at the bottom and smaller at the top (larger on the main oil passage side).

[0020] 5. The manufacturing method of the forged oil rail structure of the present invention, wherein the positioning of the pressure bearing seat is reliable, the manufacturing difficulty is reduced, the failure rate is reduced, the production efficiency is high, the product quality is improved and the product service life is extended. Attached Figure Description

[0021] Figure 1 The stress condition of the existing forged oil rail CAE analysis is as follows: main oil passage 10mm, radial flow passage 3.2mm.

[0022] Figure 2 The second stress condition for the existing forged oil rail CAE analysis is: main oil channel 10mm, radial flow channel 6mm.

[0023] Figure 3 The stress condition of the existing forged oil rail CAE analysis is as follows: main oil channel 9mm, radial flow channel 6mm.

[0024] Figure 4 This is a schematic diagram of the structure of the present invention.

[0025] Figure 5 This is a perspective view of the pressure-bearing seat in this invention.

[0026] Figure 6 This is a cross-sectional view of the pressure bearing seat in this invention.

[0027] Figure 7 This is an assembly structure diagram of the main body of the pressure bearing seat and the forged oil rail in this invention.

[0028] Figure 8 This is the first case of stress analysis of forged oil rails in this invention using CAE.

[0029] Figure 9 This is the first case of stress analysis of forged oil rails in this invention using CAE. Detailed Implementation

[0030] The present invention will be further described below with reference to the embodiments.

[0031] Please see Figure 4-7This invention discloses a structure for a forged oil rail. As shown in the figure, several pressure-bearing seats 2 are provided; the main body 1 of the forged oil rail and the pressure-bearing seats 2 are assembled by brazing to tightly connect the main body of the forged oil rail to the pressure-bearing seats.

[0032] like Figure 8 , 9 As shown, the tearing of the forged oil rail body 1 can be completely overcome after the addition of the pressure bearing seat 2.

[0033] In this invention, the assembly and positioning method between the main body of the forged oil rail and the pressure seat is press-fit positioning or laser welding spot welding positioning.

[0034] In this invention, the pressure bearing seat is brazed to connect the pressure bearing seat to the main body of the forged oil rail by means of copper plating on the surface. Because the gap between the main body of the forged oil rail and the pressure bearing seat is very small and the position is quite demanding, methods such as using copper rings or applying copper paste / flux are not feasible. Therefore, this invention uses copper plating on the surface of the pressure bearing seat for brazing to connect the pressure bearing seat to the main body of the forged oil rail.

[0035] In this invention, regarding the material selection of the pressure bearing seat, due to the mechanical properties of the material, the crystal lattice changes, and after brazing, the material itself will revert to the original mechanical properties of the parent material; the pressure bearing seat uses a material with a higher yield strength than the main body of the forged oil rail, so as to resist higher stress pressure and achieve the reliability and durability of the design.

[0036] In this invention, the pressure bearing seat adopts a stepped segmented pressure bearing structure, with the lower part being larger and the upper part smaller, and the side closer to the main oil passage being larger.

[0037] The present invention also discloses a method for manufacturing the structure of the forged oil rail as described above, characterized in that: the pressure seat is pre-positioned on the tooling, the initial positioning and alignment are performed by the dummy, the pressure seat is adsorbed by vacuum, the forged oil rail is fixed on the tooling at the same time, the clamping mechanism is activated, and the oil cylinder clamps the oil rail; after activation, the pressure seat is pressed into the oil passage hole of the forged oil rail.

[0038] The method further includes brazing the pressure seat to the main body of the forged oil rail by means of copper plating on the surface of the pressure seat.

[0039] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. All equivalent changes and modifications made within the scope of the claims of this invention should be considered within the technical scope of this invention.

Claims

1. A structure for a forged hydraulic rail, characterized in that... It is equipped with several pressure-bearing seats; the main body of the forged oil rail is assembled with the pressure-bearing seats by brazing.

2. The structure of the forged oil rail according to claim 1, characterized in that... The assembly and positioning method between the main body of the forged oil rail and the pressure seat is press-fit positioning or laser welding spot welding positioning.

3. The structure of the forged oil rail according to claim 1, characterized in that... The pressure bearing seat is brazed by copper plating on its surface to connect the pressure bearing seat to the main body of the forged oil rail.

4. The structure of the forged oil rail according to claim 1, characterized in that... Regarding the material selection for this pressure bearing seat, due to the mechanical properties of the material, the crystal lattice changes. After brazing, the material itself will revert to the original mechanical properties of the parent material. The pressure bearing seat uses a material with a higher yield strength than the main body of the forged oil rail, in order to withstand higher stress pressure and achieve the reliability and durability of the design.

5. The structure of the forged oil rail according to claim 1, characterized in that... The pressure bearing seat adopts a stepped segmented pressure bearing structure, with the lower part being larger and the upper part smaller, and the side closer to the main oil passage being larger.

6. A method for manufacturing a forged oil rail structure as described in claim 1, 2, 3, 4, or 5, characterized in that: The pressure seat is pre-positioned on the tooling, and the artificial body is used for initial positioning and alignment. The pressure seat is adsorbed by vacuum method, and the forged oil rail is fixed on the tooling at the same time. The clamping mechanism is started, and the oil cylinder clamps the oil rail. After starting, the pressure seat is pressed into the oil passage hole of the forged oil rail.

7. The method for manufacturing the forged oil rail structure according to claim 6, characterized in that: The method further includes brazing the pressure seat to the main body of the forged oil rail by means of copper plating on the surface of the pressure seat.

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