Machining method for deep hole inner groove of nozzle
By combining mechanical and electrolytic machining, the problems of low machining efficiency and difficulty in controlling precision in the deep hole inner groove of nozzles have been solved, achieving efficient and economical machining results and meeting the machining needs of high-temperature alloy irregular structures.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-16
- Publication Date
- 2026-03-10
AI Technical Summary
In the existing technology, the machining efficiency of the nozzle deep hole inner groove is low, the cost is high, and the accuracy is difficult to control stably. In particular, the machining of irregular structures of high temperature alloy materials has problems such as rapid wear of boring tools and difficulty in controlling the dimensional accuracy of electrolytic machining.
A combination of machining and electrolytic machining is used. First, a reference hole is formed in the nozzle substrate. Then, a reference ring groove is formed by electrolytic machining. Finally, the rear and front sections of the reference ring groove are processed by machining and electrolytic machining respectively to achieve efficient removal of excess material and precise control of dimensions.
It achieves efficient machining of the inner groove of the nozzle deep hole, reduces the frequency and cost of tool replacement, improves the stability and consistency of machining accuracy, adapts to the machining needs of different areas, and avoids the defects of a single machining method.
Smart Images
Figure CN121624563A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of machining, and specifically to a method for machining a deep-hole inner groove in a nozzle. Background Technology
[0002] In a certain type of ammonia fuel injector assembly, the nozzle is made of high-temperature alloy material to meet the performance requirements under ammonia fuel combustion conditions. The core functional component of this nozzle—the oil chamber—adopts a deep-hole irregular-shaped internal groove structure, which is one of the key structures to ensure the normal operation of the injector.
[0003] For the machining of nozzle oil chambers, there are two main conventional solutions in the existing technology: one is the mechanical machining solution, which is formed by boring and grooving; the other is the electrolytic special machining solution, which is to complete the machining based on the principle of electrolysis.
[0004] However, the inner groove of the nozzle is not only larger in diameter and deeper than that of conventional nozzles, but also has an irregular structural feature. Furthermore, it is made of a high-temperature alloy, a difficult-to-machine material, which leads to significant drawbacks in existing conventional machining methods. If a boring bar is used for grooving, the high hardness and high machining resistance of the high-temperature alloy result in extremely low machining efficiency. On the other hand, the material's strong wear resistance causes rapid wear of the boring bar, making it impossible for a single boring bar to complete the machining of a single inner groove. Frequent tool changes are necessary, significantly increasing tool procurement and replacement costs. Moreover, tool changes easily leave tool marks on the inner groove surface, affecting machining quality. If an electrolytic special machining method is used, since the nozzle's inner groove directly intersects with the sealing seat surface, the electrolyte easily corrodes the sealing seat surface during electrolysis. Simultaneously, the dimensional accuracy of electrolytic machining is difficult to control stably, failing to meet the product's preset accuracy requirements, thus affecting the working performance of the nozzle and even the entire ammonia fuel injector assembly. Summary of the Invention
[0005] The purpose of this invention is to provide a machining method for the inner groove of a deep hole in a nozzle, so as to solve the problems of low efficiency, high cost and inability to reliably guarantee machining accuracy of existing machining methods.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention discloses a method for machining a deep-hole inner groove in a nozzle, comprising: S1, a reference hole is formed in the nozzle substrate by mechanical machining; S2, a reference ring groove is formed in the preset area of the reference hole by electrolytic machining; S3, the rear section of the reference annular groove is machined to the preset diameter; S4, the front section of the reference ring groove is electrolytically processed to a preset shape.
[0007] Furthermore, in S1, a reference hole is formed in the nozzle substrate by drilling, reaming, or drilling and boring.
[0008] Furthermore, during electrolytic machining in S2, the electrode diameter in the electrolytic machining fixture is 0.5~2.0mm smaller than the inner diameter of the reference hole, the electrolytic machining voltage is set to 5~35V, and the electrolytic time is set to 200~400s.
[0009] Furthermore, in step S3, the rear section of the reference ring groove is machined to a preset diameter by boring, and the radius of the boring tool tip arc is 0.2~0.4mm; the boring process includes rough boring and fine boring, and the appropriate machining parameters are adjusted according to the surface quality after each boring.
[0010] Furthermore, during electrolytic machining in S4, the electrode diameter in the electrolytic machining fixture is 0.5~2.0mm smaller than the inner diameter of the reference hole, the electrolytic machining voltage is set to 10~40V, and the electrolytic time is set to 500~700s.
[0011] The present invention has the following unexpected beneficial effects: 1. The processing method described in this invention adopts a combined approach of mechanical machining and electrolytic machining. It leverages the advantages of mechanical machining in datum positioning and precise control of local dimensions, while utilizing the efficiency advantage of electrolytic machining in removing large areas of excess material. This avoids the inherent defects of either single mechanical machining or single electrolytic machining, forming a composite process system suitable for machining the inner groove of deep holes in nozzles. Specifically, S1 and S2 are roughing stages, focusing on efficient removal of excess material; S3 and S4 are finishing stages, focusing on precise dimensional control. This setup avoids interference from residual material in the early stages on subsequent finishing processes, while reducing excessive reliance on equipment and cutting tools for finishing, achieving a balance between the orderly nature and economic efficiency of the processing flow.
[0012] 2. The method described in this invention adopts mechanical processing and electrolytic processing respectively for different processing scenarios of the rear and front sections of the reference ring groove, so that the processing technology of each region matches the dimensional accuracy requirements and structural characteristics of that region, thereby reducing processing deviations or quality defects caused by mismatch between the process and the regional characteristics.
[0013] 3. The present invention first forms a reference hole through mechanical processing to provide a stable positioning reference for subsequent electrolytic processing; the reference ring groove formed thereafter provides a unified reference for subsequent irregular inner groove partition processing, avoiding dimensional drift caused by the lack of reference during processing and improving the stability of overall processing accuracy. Attached Figure Description
[0014] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention.
[0015] Figure 1 A schematic flowchart of the machining method for the nozzle deep hole inner groove according to an embodiment of the present invention is shown.
[0016] Figure 2 A schematic diagram of the nozzle structure after the reference hole is formed by machining is shown.
[0017] Figure 3 A schematic diagram of the nozzle structure after the reference annular groove is formed by electrolytic machining is shown.
[0018] Figure 4 A schematic diagram of the nozzle structure following the machining of the reference annular groove is shown.
[0019] Figure 5 A schematic diagram of the nozzle structure is shown below the front section of the reference annular groove in electrolytic machining.
[0020] Figure 6 A schematic diagram of the water outlet cap is shown when the reference annular groove is formed by electrolytic machining.
[0021] Figure 7 A schematic diagram of the water outlet cap is shown when the front section of the reference annular groove is electrolytically processed. Detailed Implementation
[0022] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.
[0023] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.
[0024] In one embodiment, see Figure 1 As shown, the present invention provides a method for machining a deep-hole inner groove in a nozzle, comprising: S1, a reference hole is formed in the nozzle substrate by mechanical machining; S2, a reference ring groove is formed in the preset area of the reference hole by electrolytic machining; S3, the rear section of the reference annular groove is machined to the preset diameter; S4, the front section of the reference ring groove is electrolytically processed to a preset shape.
[0025] The processing method described in this invention employs a combination of machining and electrolytic machining. It leverages the advantages of machining in datum positioning and precise control of local dimensions, while utilizing the efficiency of electrolytic machining in removing large areas of excess material. This avoids the inherent limitations of either single machining or single electrolytic machining, forming a composite process system suitable for machining deep-hole inner grooves in nozzles. Specifically, S1 and S2 are roughing stages, focusing on efficient removal of excess material; S3 and S4 are finishing stages, focusing on precise dimensional control. This setup avoids interference from residual material in the early stages on subsequent finishing processes, while reducing excessive reliance on equipment and cutting tools for finishing, achieving a balance between the orderly nature and economic efficiency of the processing flow.
[0026] The method described in this invention adopts mechanical processing and electrolytic processing respectively for different processing scenarios of the rear and front sections of the reference ring groove, so that the processing technology of each region matches the dimensional accuracy requirements and structural characteristics of that region, thereby reducing processing deviations or quality defects caused by mismatch between the process and the regional characteristics.
[0027] This invention first forms a reference hole through machining, providing a stable positioning reference for subsequent electrolytic machining; the subsequently formed reference annular groove provides a unified reference for the subsequent machining of irregular inner grooves, avoiding dimensional drift caused by the lack of a reference during the machining process and improving the stability of the overall machining accuracy.
[0028] In a preferred embodiment of the present invention, in step S1, a reference hole is formed in the nozzle substrate by drilling, reaming, or drilling and boring.
[0029] See Figure 2 As shown, a reference hole 2 is formed in the nozzle base 1 by drilling, reaming or drilling and boring.
[0030] This preferred embodiment employs a combination of drilling and reaming or drilling and boring. First, the drill removes most of the excess material, then the reamer or boring tool performs finishing. This significantly improves the dimensional accuracy, roundness, coaxiality, and surface quality of the reference hole. Drilling and reaming are suitable for small to medium diameter holes with moderate depths and high requirements for surface roughness and dimensional accuracy; drilling and boring are suitable for large diameter, deep holes with extremely high coaxiality requirements. By providing two processing combinations, this preferred embodiment can adapt to the processing needs of nozzles of different specifications, improving the versatility and flexibility of the process.
[0031] The appropriate carbide cutting tool can be selected based on the dimensions of the inner groove of the part. Simultaneously, the inner groove and the clamping outer circle must maintain high precision to ensure that the part's machining requirements are met during subsequent S3 machining. Furthermore, the selected lathe must have high-pressure internal cooling capabilities, and the selected carbide cutting tool must have internal cooling holes. The appropriate machining parameters can be adjusted according to the surface quality after machining.
[0032] In a preferred embodiment of the present invention, during electrolytic machining in S2, the electrode diameter in the electrolytic machining fixture is 0.5~2.0mm smaller than the inner diameter of the reference hole, the electrolytic machining voltage is set to 5~35V, and the electrolytic time is set to 200~400s.
[0033] See Figure 3 As shown, after electrolytic machining is completed, a reference annular groove 3 obtained by electrolytic machining is formed in the preset area of the reference hole 2 of the nozzle substrate 1.
[0034] In this preferred embodiment, a single-sided gap of 0.25~1.0mm is maintained between the electrode and the reference hole 2, which is conducive to uniform electrolyte flow and avoids excessively high or low local current density, thereby ensuring that the electrolysis rate is consistent in all parts of the reference annular groove 3. Furthermore, since the gap is large enough, direct contact between the electrode and the hole wall of the reference hole 2 can be avoided to prevent short circuits, and interference caused by processing vibration and clamping errors is also reduced.
[0035] The electrolytic machining voltage is set to 5~35V. If the voltage is too low, the electrolysis speed will be slow and the efficiency will be low; if the voltage is too high, it will aggravate local corrosion and affect dimensional accuracy and surface roughness. Furthermore, step S2 is a roughing stage, which requires the rapid removal of most of the excess material from the annular groove. This voltage range can provide sufficient electrolytic energy to meet the cycle time requirements of mass production.
[0036] Setting the electrolysis time to 200-400 seconds ensures that most of the allowance in the area corresponding to the reference ring groove 3 is removed, providing a uniform and appropriate allowance for the subsequent finishing processes S3 and S4. If the time is set too short, insufficient allowance removal will occur, increasing the burden on subsequent machining; if the time is set too long, over-corrosion may occur, damaging the geometric accuracy of the reference hole.
[0037] See Figure 6 As shown, the first water outlet cap 4 of the electrolytic processing device S2 includes a first main body 41 and a first enlarged diameter end 42 connected to the end of the first main body 41. The first main body 41 is axially provided with a first drain channel 411 penetrating one side end face of the first main body 41, and the side of the first main body 41 is provided with a side hole 412 communicating with the first drain channel 411. The side end face of the first enlarged diameter end 42 opposite to the main body 41 is provided with a tapered portion 421 that matches the limiting tapered surface 21 in the reference hole 2.
[0038] During electrolytic processing, the conical part 421 of the first water outlet cap 4 fits against the limiting conical surface 21 in the reference hole 2. Electrolyte in the gap between the first water outlet cap 4 and the reference hole 2 enters the first drain channel 411 from the side hole 412 and flows back through the first drain channel 411.
[0039] In a preferred embodiment of the present invention, in step S3, the rear section of the reference ring groove 3 is machined to a preset diameter by boring, and the radius of the tip arc of the boring tool is 0.2~0.4mm; the boring process includes rough boring and fine boring, and the appropriate machining parameters are adjusted according to the surface quality after each boring.
[0040] See Figure 4 As shown, after the machining of S3 is completed, the rear section of the reference ring groove 3 is precision machined to the preset size.
[0041] High-temperature alloys have high hardness and high cutting resistance during machining. If the tool tip radius is too small, local stress concentration at the tool tip can lead to rapid chipping or wear, requiring frequent tool changes. If the tool tip radius is too large, it will increase the cutting contact area and intensify the tool load. A radius range of 0.2~0.4mm can disperse cutting stress, reduce the intense friction between the tool tip and the high-temperature alloy, extend tool life, reduce tool costs, and avoid machining interruptions due to tool chipping.
[0042] This preferred embodiment employs a distributed boring method, meaning that most of the residual material can be quickly removed through the rough boring process, avoiding leaving a large amount of material for the finish boring. If only a single finish boring operation is used, excessive material will lead to accelerated tool wear and increased machining vibration, which will negatively impact accuracy. The division of labor between rough boring for material removal and finish boring for precision control significantly improves overall machining efficiency and is suitable for batch production.
[0043] After each boring operation, the appropriate machining parameters (such as cutting speed, feed rate, and depth of cut) are adjusted based on the surface quality. This addresses uncertainties in the machining process; even within the same batch of nozzle substrates 1, slight differences may exist in the material uniformity of the high-temperature alloy and the initial accuracy of the datum hole 2. Furthermore, tool wear and machine vibration during machining can also affect surface quality. Dynamic parameter adjustment corrects these deviations in real time, preventing the application of fixed parameters that could lead to defective parts. On the other hand, it ensures consistency in batch processing. By adjusting parameters based on surface quality feedback, the machining quality of the rear section of the datum annular groove 3 in each nozzle substrate 1 remains stable, reducing the defect rate in batch production and improving process repeatability.
[0044] In a preferred embodiment of the present invention, during electrolytic machining in S4, the electrode diameter in the electrolytic machining fixture is 0.5~2.0mm smaller than the inner diameter of the reference hole, the electrolytic machining voltage is set to 10~40V, and the electrolytic time is set to 500~700s.
[0045] In this preferred embodiment, the electrode diameter in the electrolytic machining fixture is 0.5~2.0 mm smaller than the inner diameter of the reference hole, allowing the electrolyte to flow uniformly and ensuring stable electrolysis. Similarly, an appropriate gap prevents direct contact between the electrode and the workpiece, avoiding short circuits, and also prevents excessive corrosion caused by excessively small gaps leading to localized high current densities. Gap uniformity is a key factor in the dimensional accuracy of electrolytic machining; this parameter setting ensures that the front annular groove achieves the preset shape. Compared to step S2 (5~35V), this preferred embodiment sets a slightly higher voltage range, suitable for fine machining of the front annular groove, enabling more precise dimensional control. If the voltage is set too low, the machining speed will be slow and inefficient; if the voltage is set too high, surface ablation and dimensional deviations may occur. Furthermore, within this voltage range, the current density during electrolysis is moderate, facilitating precise control of the machining speed by adjusting the voltage. See Figure 7 As shown, the second water outlet cap 5 of the electrolytic processing device S4 includes a second main body 51 and a second enlarged diameter end 52 connected to the end of the second main body 51. The second main body 51 is axially provided with a second drain channel 511 penetrating both end faces of the second main body 51. The second enlarged diameter end 52 is provided with a guide slope 521 on the side end face opposite to the main body 51.
[0046] During electrolytic processing, the guide slope 521 of the second water outlet cap 5 is located at the junction of the front and rear sections of the reference ring groove 3. Electrolyte in the gap between the second water outlet cap 5 and the reference hole 2 enters from the guide slope 521 to the rear opening of the second water outlet cap 5, and then flows back through the second drain channel 511.
[0047] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.
Claims
1. A method for processing a deep hole inner groove of a nozzle, characterized by, The method comprises the following steps: S1, forming a reference hole in the nozzle base by mechanical processing; S2, forming a reference ring groove in a preset area of the reference hole by electrolytic processing; S3, mechanically processing the rear section of the reference ring groove to a preset hole diameter; S4, electrolytically processing the front section of the reference ring groove to a preset shape.
2. The method of claim 1, wherein: In the S1, the reference hole is formed in the nozzle base by drilling, reaming or drilling and boring.
3. The method of claim 1, wherein: In the S2, when electrolytic processing, the electrode diameter in the electrolytic processing clamp is 0.5-2.0 mm smaller than the inner diameter of the reference hole, the electrolytic processing voltage is set to 5-35 V, and the electrolytic time is set to 200-400 s.
4. The method of claim 1, wherein: In the S3, the rear section of the reference ring groove is processed to a preset hole diameter by boring, and the nose radius of the boring tool is 0.2-0.4 mm; the boring process includes a rough boring process and a fine boring process, and the processing parameters are adjusted according to the surface quality after each boring.
5. The method of claim 1, wherein: In the S4, when electrolytic processing, the electrode diameter in the electrolytic processing clamp is 0.5-2.0 mm smaller than the inner diameter of the reference hole, the electrolytic processing voltage is set to 10-40 V, and the electrolytic time is set to 500-700 s.