Douglas fir type mortise and tenon structure deflection abrasive water jet strengthening method and system

Abstract

The application provides a fir-type mortise and tenon joint structure deflection abrasive water jet strengthening method and system. The method uses a deflection abrasive water jet nozzle and a three-sided shielding strengthening tool to strengthen the surface of a workpiece. The system uses the above method. The application can solve the problems of "physical inaccessibility" (cannot enter) and "jet shadow" (cannot be sprayed / angle is not correct) of traditional strengthening tools in the extremely limited space of a fir-type mortise and tenon joint structure (deep groove, multiple teeth, reverse buckle), thereby realizing full coverage and uniform stress distribution of surface strengthening.

Description

Technical Field

[0001] This invention relates to the field of waterjet technology, specifically to a method and system for strengthening waterjet with deflecting abrasive using a fir tree-shaped tenon joint structure. Background Technology

[0002] The fir tree-shaped tenon joint is a critical component connecting the turbine disk and blades of aero-engines, and it withstands extremely high centrifugal loads, vibration loads, and thermal cycling loads during service. Engineering practice shows that the root arc of the tenon groove and the contact surface are high-risk areas for fatigue crack initiation, and their surface integrity directly determines the service life of the core component. Therefore, introducing residual compressive stress using surface strengthening technology is an essential process. Currently, the strengthening of this type of structure mainly adopts shot peening or conventional waterjet strengthening technology. However, existing technologies face insurmountable geometric and methodological bottlenecks when dealing with fir tree-shaped tenon joints: First, accessibility is poor. The fir tree-shaped structure has typical characteristics of "deep grooves," "multiple teeth," and "concave," resulting in extremely limited space. Traditional abrasive waterjet nozzles are usually straight-tube designs and are relatively large in size. If sprayed outside the trough, the high-pressure water jet will be blocked by the upper tooth profile due to the straight-line propagation characteristics of the jet, failing to directly impact the deep tooth root arc and forming a significant "jet shadow zone." If an attempt is made to insert the nozzle into the trough, traditional straight nozzles are prone to physical interference (collision) with the trough wall, making operation impossible. Secondly, uniform reinforcement is difficult to control. Even if a small-sized straight nozzle is used to barely enter, existing methods typically employ a single spray angle to scan along the contour. However, the tenon structure contains a flat load-bearing surface and a tooth root arc with extremely high curvature. For flat surfaces, a certain angle is suitable to balance cutting cleanliness and impact. However, for narrow tooth root arcs, if the angle is too small, the jet energy will be severely dissipated, failing to form a sufficient residual compressive stress layer. Existing technologies lack a zonal processing method that can automatically adjust the incident strategy according to different geometric features, resulting in insufficient reinforcement of critical parts and potential over-reinforcement of non-critical parts. Finally, the abrasive utilization rate is low and environmental pollution occurs. Existing waterjet enhancement methods are mostly carried out in open or simply shielded environments. After high-speed abrasives hit the wall, they splash everywhere, which not only wastes abrasives but also makes waste liquid recovery difficult and deteriorates the working environment. Summary of the Invention

[0003] This invention provides a method and system for strengthening fir tree-shaped tenon joint structures with deflected abrasive waterjet, which solves the problems of "physical inaccessibility" (cannot enter) and "jet shadow" (cannot be sprayed / incorrect angle) of traditional strengthening tools in the interior of fir tree-shaped tenon joint structures (deep groove, multi-tooth, undercut) where space is extremely limited, thereby achieving full coverage and uniform stress distribution of surface strengthening.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A method for surface strengthening of a fir tree-shaped tenon joint structure using deflected abrasive waterjet nozzles and a three-sided shielding strengthening fixture is disclosed. The method includes the following steps: Step S1: Workpiece clamping; the fir tree-shaped tenon joint workpiece to be strengthened is fixed within the three-sided shielding strengthening fixture; the three-sided shielding strengthening fixture includes a base and shielding walls disposed on the base, the shielding walls and the base together forming a semi-closed receiving cavity with one side open; the workpiece is located within the semi-closed receiving cavity; Step S2: Trajectory planning; based on the tooth profile characteristics of the workpiece, the area to be strengthened is divided into contact bearing areas. The process involves several steps: Step S3: Nozzle posture adjustment; controlling the deflecting abrasive water jet nozzle to extend from the opening into the semi-enclosed receiving cavity; Step S4: Strengthening operation; controlling the deflecting abrasive water jet nozzle to move along the area to be strengthened and spray abrasive water jet; wherein, when strengthening the contact bearing surface area, the angle between the nozzle axis and the normal to the workpiece surface is controlled to be within a first angle range; when strengthening the complex narrow contour surface area, the angle between the nozzle axis and the normal to the workpiece surface is controlled to be within a second angle range; the lower limit of the second angle range is greater than the upper limit of the first angle range.

[0005] To achieve the above objectives, the present invention also provides the following technical solutions: A fir-tree-shaped tenon joint structure deflecting abrasive waterjet reinforcement system, the system comprising: a six-axis robotic arm; a deflecting abrasive waterjet nozzle held by the six-axis robotic arm, the nozzle having a curved connecting pipe; a three-sided shielding reinforcement fixture having a semi-enclosed receiving cavity capable of reflecting the jet; and a controller configured to perform the above-described method.

[0006] Compared with the prior art, the present invention has achieved the following beneficial effects: 1. Overcoming "geometric blind spots" and achieving full coverage reinforcement: By adopting a deflecting abrasive water jet nozzle and coordinating with an insertion action, the technical solution breaks through the "straight line constraint" of traditional straight nozzles; the nozzle can bypass the undercut structure of the tenon and physically probe into the depth of the narrow tooth groove, eliminating the "reinforcement blind spot" caused by the nozzle's inability to reach in traditional methods, and ensuring full coverage of complex surfaces; 2. Eliminate stress concentration and optimize strengthening quality: The workpiece is divided into "contact bearing surface" and "complex narrow contour surface" by trajectory planning (S2), and a differentiated angle control strategy is implemented. The narrow surface adopts a larger near normal angle. This solves the problem of uneven strengthening effect caused by uniform method parameters on surfaces with different curvatures. Especially at the tooth root arc, which is most prone to fatigue failure, sufficient residual compressive stress implantation depth is ensured, which significantly improves the fatigue life of the workpiece. 3. Environmental constraints and energy gains: By constructing a semi-enclosed containment cavity through a three-sided shielding reinforcement tool, the high-speed splashing waste abrasive and waste liquid are effectively constrained, improving the workshop working environment. On the other hand, by utilizing the reflective effect of the shielding wall, some of the rebounded abrasive forms a secondary micro-forging or cleaning effect on the non-main jet area of ​​the workpiece, improving surface integrity without increasing energy consumption. Attached Figure Description

[0007] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0008] Figure 1 This is a schematic diagram illustrating the reinforcement trajectory of the contact surface area in a fir-tree-shaped tenon joint structure. Figure 2 This is a schematic diagram of the reinforcement trajectory in the straight section area of ​​the fir tree-shaped tenon joint structure; Figure 3 This is a schematic diagram of the complex contour surface reinforcement trajectory of a fir tree-shaped tenon joint structure; Figure 4 This is a simplified structural diagram of a deflecting abrasive water jet nozzle. Figure 5 This is a schematic diagram of the three-dimensional structure of the reinforced tooling with three-sided shielding; Figure 6 This is a BB-direction sectional view of a three-sided shielded reinforced tooling; Figure 7 This is a cross-sectional view of the three-sided shielding reinforced tooling along the AA direction; Figure 8 This is a diagram showing the implementation of a deflecting nozzle extending into the tooling for reinforcement operations; Figure 9 This is a partial cross-sectional schematic diagram of the nozzle operating inside the tooling; Figure 10 This is a three-dimensional structural diagram of a deflecting abrasive water jet nozzle; Figure 11 This is a three-dimensional structural diagram of a three-sided shielded reinforced tooling. Figure 12 This is a schematic diagram showing the distribution of the reinforced areas of the workpiece within the tooling; Figure 13 It is a schematic diagram of the assembly and positioning of tooling fixtures and workpieces; Figure 14 It is a cross-sectional three-dimensional view of the three-sided shielded reinforced tooling; Figure 15 This is a schematic diagram of the overall structure of an automated deflecting abrasive waterjet reinforcement system; Figure 16This is a close-up diagram of a deflecting nozzle extending into the mortise groove. Figure 17 This is a schematic diagram illustrating the principle of spray angle and trajectory control in the contact bearing surface area; Figure 18 It is a partial sectional three-dimensional view of the reinforcement work in the contact load-bearing surface area; Figure 19 It is a partial sectional 3D view of the reinforcement work on a complex and narrow contour area; Figure 20 It is a schematic diagram of the principle of spray angle and trajectory control in complex and narrow contour areas.

[0009] Explanation of reference numerals in the attached figures 10-Three-sided shielding reinforced fixture; 11-Base; 12-Shielding wall; 121-First side plate (left / right side wall); 122-Second side plate (right / left side wall); 123-Back plate; 13-Semi-enclosed receiving cavity; 14-Flow guiding structure; 141-Inclined flow channel (or drain hole). 20-Tooling fixture; 21-Positioning groove; 30-Workpiece (fir tree-shaped tenon joint structure workpiece); 40 - Deflecting abrasive waterjet nozzle; 41 - Nozzle body; 42 - Connecting pipe; 50 - Six-axis robotic arm.

[0010] D, E, and F represent the reinforcement locations in the contact surface area of ​​the fir tree-shaped tenon joint structure; G and H represent the reinforcement positions in the straight section area of ​​the fir tree-shaped tenon joint structure; I, J, and K represent the locations where the complex contours of the fir tree-shaped tenon joint structure are reinforced. RS represents the location of the reinforced area in the fir tree-shaped tenon joint structure. Detailed Implementation

[0011] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be understood that the specific embodiments described herein are only for illustration and explanation of the present invention and are not intended to limit the present invention.

[0012] Any specific numerical value (including the endpoints of the numerical range) disclosed in this invention is not limited to the exact value, but should be understood to also cover values ​​close to the exact value, such as all possible values ​​within ±5% of the exact value. Furthermore, for the disclosed numerical range, one or more new numerical ranges can be obtained by arbitrarily combining the endpoint values ​​of the range, the endpoint values ​​with specific point values ​​within the range, and the specific point values. These new numerical ranges should also be considered as specifically disclosed in this invention.

[0013] The terminology used in this invention is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” as used herein are intended to include the plural forms as well. The terms “comprising,” “including,” “containing,” and “having” are inclusive and thus describe the presence of said features, elements, compositions, steps, integers, operations, and / or components, but do not exclude the presence or inclusion of one or more other features, integers, steps, operations, elements, components, and / or sets thereof. Although the open-ended term “comprising” should be understood as a non-limiting term used to describe and claim the various embodiments described in this invention, in some aspects it may instead be understood as a more restrictive and limiting term, such as “consisting of” or “essentially composed of.” Thus, for any given embodiment describing compositions, materials, components, elements, features, integers, operations, and / or method steps, the invention also particularly includes embodiments consisting of or substantially consisting of such compositions, materials, components, elements, features, integers, operations, and / or method steps. In the case of “consisting of…”, alternative embodiments exclude any additional compositions, materials, components, elements, features, integers, operating and / or method steps. In the case of “essentially composed of…”, any additional compositions, materials, components, elements, features, integers, operating and / or method steps that substantially affect the essential and novel characteristics are excluded from such embodiments. However, any compositions, materials, components, elements, features, integers, operating and / or method steps that do not substantially affect the essential and novel characteristics may be included in the embodiments.

[0014] Any method steps, procedures, and operations described in this invention should not be construed as necessarily requiring them to be performed in the specific order discussed or shown, unless explicitly specified. It should also be understood that, unless otherwise stated, additional or alternative steps may be used.

[0015] In this invention, except where expressly stated, any matters or issues not mentioned are directly applicable to those known in the art without any modification. Furthermore, any embodiment described in this invention can be freely combined with one or more other embodiments described in this invention, and the resulting technical solutions or concepts are considered part of the original disclosure or original record of this invention, and should not be regarded as new content not disclosed or anticipated by this invention, unless those skilled in the art consider the combination to be clearly unreasonable.

[0016] Unless otherwise stated, the terminology used in this invention has the same meaning as commonly understood by those skilled in the art. If a term is defined in this invention and its definition differs from the common understanding in the art, the definition of this invention shall prevail.

[0017] As mentioned above, in the existing technology, the problems of "physical inaccessibility" (cannot enter) and "jet shadow" (cannot be sprayed / incorrect angle) of traditional strengthening tools in the extremely space-constrained interior of fir tree-shaped tenon joint structures (deep grooves, multi-tooth, and undercuts) remain unsolved, and it is impossible to achieve full coverage and uniform stress distribution surface strengthening. In view of this, the present invention provides the following technical solution to solve the above problems.

[0018] First aspect See Figure 15This invention provides a method for surface strengthening of a fir tree-shaped tenon joint structure using deflected abrasive waterjet. The method utilizes a deflected abrasive waterjet nozzle 40 and a three-sided shielding strengthening fixture 10 to strengthen the surface of a workpiece 30. The method includes the following steps: Step S1: Workpiece clamping; The workpiece 30 with the fir tree-shaped tenon joint structure to be strengthened is fixed within the three-sided shielding strengthening fixture 10. The three-sided shielding strengthening fixture 10 includes a base 11 and a shielding wall 12 disposed on the base 11. The shielding wall 12 and the base 11 together form a semi-closed receiving cavity 13 with an opening on one side. The workpiece 30 is located within the semi-closed receiving cavity 13. Step S2: Trajectory planning; Based on the tooth profile characteristics of the workpiece 30... The area to be strengthened is divided into a contact bearing surface area and a complex narrow contour surface area; Step S3: Nozzle posture adjustment; control the deflecting abrasive water jet nozzle 40 to extend from the opening into the semi-closed receiving cavity 13; Step S4: Strengthening operation; control the deflecting abrasive water jet nozzle 40 to move along the area to be strengthened and spray abrasive water jet; wherein, when strengthening the contact bearing surface area, the angle between the nozzle axis and the normal to the surface of the workpiece 30 is controlled to be a first angle range; when strengthening the complex narrow contour surface area, the angle between the nozzle axis and the normal to the surface of the workpiece 30 is controlled to be a second angle range; the lower limit of the second angle range is greater than the upper limit of the first angle range. By using the deflecting abrasive water jet nozzle 40 in conjunction with the three-sided shielding strengthening fixture 10, and combining it with the differentiated angle control method for different areas (contact bearing surface and complex narrow contour surface), full coverage and no dead angle strengthening of complex concave surfaces such as fir tree-shaped tenon joint structures is achieved. By providing operational constraints through the semi-enclosed receiving cavity 13, and by using the deflection nozzle to penetrate into narrow spaces and adjust the incident angle according to geometric features, the problem of "processing blind spots" such as the difficulty of penetrating the root of the tenon groove in existing straight nozzle technology is effectively solved, as well as the technical defects of insufficient coverage of complex curved surfaces and uneven stress distribution caused by single-angle strengthening.

[0019] It should be noted that the 'deflection' mentioned in this invention refers to the nozzle structure having a curved feature in its geometry, thereby changing the initial jet direction and enabling it to bypass obstacles.

[0020] See Figure 10 and Figure 16In some embodiments of the present invention, the deflecting abrasive waterjet nozzle 40 includes a nozzle body 41 and a connecting pipe 42. The connecting pipe 42 has a curved section, such that the axis of the nozzle body 41 is set at a fixed angle with the input end axis of the connecting pipe 42. The length of the nozzle body 41 is smaller than the opening distance between adjacent grooves of the fir tree-shaped tenon joint structure, and is configured to extend into the groove. By setting the connecting pipe 42 with a curved section and the nozzle body 41 with a length smaller than the opening distance between the grooves, an insertion structure that can physically avoid interference is constructed, realizing the function of directly sending the jet source into the depth of narrow grooves without touching the inner wall of the workpiece. This further solves the problem that standard nozzles cannot approach the strengthening target point due to physical size interference when processing deep and narrow grooves, resulting in key parts such as the root of the tooth not obtaining effective strengthening strength.

[0021] See Figure 17 In some embodiments of the present invention, the first angle range is 45°~55°; the second angle range is 70°~90°. By defining specific angle parameters, a 45°~55° incident angle is used on flat contact bearing surfaces to balance cutting and impact, while a large angle (near normal) impact of 70°~90° is used on complex and narrow contour surfaces (such as tooth roots) that are prone to stress concentration, thereby optimizing the energy transfer efficiency. This further solves the problem that when a single incident angle is used to process surfaces with drastic curvature changes, it is easy to generate "jet shadows" or excessive energy attenuation in concave areas, resulting in insufficient depth of residual compressive stress layer in critical parts.

[0022] See Figure 11 In some embodiments of the present invention, the shielding wall 12 of the three-sided shielding reinforcement fixture 10 includes a first side plate 121 and a second side plate 122 disposed opposite to each other, and a back plate 123 connecting the backs of the first side plate 121 and the second side plate 122; the inner surfaces of the first side plate 121, the second side plate 122 and the back plate 123 are all high-hardness smooth surfaces, configured to reflect the splashed abrasive back to the surface of the workpiece 30 at a speed that still possesses polishing kinetic energy. Through the reflective cavity formed by the first side plate 121, the second side plate 122 and the back plate 123, and in conjunction with the high-hardness smooth surface design, the principle of reflection is used to achieve efficient retention and directional reflection of the kinetic energy of the splashed abrasive, thereby forming a secondary polishing effect on the surface of the workpiece 30. This further solves the problem of abrasive failure and waste after a single impact in traditional waterjet reinforcement, not only improving the abrasive utilization rate, but also effectively reducing the roughness of the reinforced surface and improving surface integrity.

[0023] See Figure 13In some embodiments of the present invention, the three-sided shielding reinforcement fixture 10 further includes a fixture clamp 20, which is disposed on the base 11 and located within the semi-enclosed receiving cavity 13. The fixture clamp 20 is provided with a positioning groove 21 adapted to the tenon shape of the workpiece 30, which is used to limit the displacement of the workpiece 30 and to make the tooth surface to be reinforced of the workpiece 30 face the opening. By providing a positioning groove 21 adapted to the tenon shape, high-rigidity positioning and clamping of the workpiece 30 within the semi-enclosed receiving cavity 13 is achieved, ensuring that the workpiece does not shift or vibrate under the impact of high-pressure water jet. This further solves the problem that the reinforcement trajectory deviates from the preset path due to unstable workpiece fixation, resulting in uneven reinforcement effect or damage to non-reinforced areas.

[0024] See Figure 14 In some embodiments of the present invention, the three-sided shielding reinforcement fixture 10 is further provided with a flow guiding structure 14, which is configured to discharge waste liquid and waste abrasive material accumulated in the semi-enclosed receiving cavity 13. The flow guiding structure 14 includes an inclined flow channel 141 or a drain hole opened below the base 11. By providing a flow guiding structure 14 (such as an inclined flow channel 141) below the base 11, the waste liquid and waste abrasive material are quickly guided and discharged, preventing them from accumulating in the semi-enclosed receiving cavity 13. This further solves the problem of the "water cushion damping effect" of accumulated liquid on the jet beam, that is, the accumulation of water buffers the jet energy, resulting in a decrease in the reinforcement effect, and the problem of waste material accumulation interfering with the nozzle movement path.

[0025] See Figure 15 In some embodiments of the present invention, in step S4, the deflecting abrasive water jet nozzle 40 is clamped and driven by a six-axis robotic arm 50; the movement trajectory of the deflecting abrasive water jet nozzle 40 is generated through offline programming. This offline programming is generated based on the three-dimensional CAD model of the workpiece 30, eliminating non-reinforced areas and combining it with the geometric dimensions of the nozzle body 41 for collision detection. By combining the six-axis robotic arm 50 with offline programming technology based on three-dimensional model collision detection, high-precision attitude control and collision-free path planning of the deflecting nozzle 40 in complex and confined spaces are achieved. This further solves the problems of not being able to perform manual teaching in confined spaces with obstructed vision, and the high risk of equipment collisions in complex multi-degree-of-freedom motion.

[0026] See Figure 1 and Figure 3In some embodiments of the present invention, the method parameters for the strengthening operation include: jet pressure of 180~220MPa, target distance of 3.5~5.5mm, and nozzle movement speed of 8~12mm / s. By strictly controlling the method parameters within a specific window (e.g., pressure of 180~220MPa), an optimal balance between strengthening strength and material surface integrity is achieved. This further solves the problems of insufficient strengthening layer depth (parameters too low) or excessive surface erosion damage (parameters too high) caused by fluctuations in method parameters, ensuring consistency in batch processing.

[0027] See Figure 1 and Figure 3 In some embodiments of the present invention, the complex and narrow contour surface region includes the root arc segment and tip arc segment of the fir tree-shaped tenon joint structure; the contact load-bearing surface region includes the straight sidewall segment of the fir tree-shaped tenon joint structure. By clearly defining the specific geometric definitions of the complex and narrow contour surface region and the contact load-bearing surface region, accurate identification and classification of the key fatigue weak points (tooth root arc) of the workpiece are achieved. This further solves the problem that the ambiguous region division makes it impossible to implement targeted large-angle reinforcement on the arc segment with high stress concentration, thus affecting the overall fatigue resistance improvement.

[0028] See Figure 6 In some embodiments of the present invention, the abrasive waterjet forms a primary impact upon contact with the surface of the workpiece 30, and a secondary impact is formed through reflection by the shielding wall 12. This secondary impact covers the area of ​​the workpiece 30 facing away from the main jet direction or performs secondary smoothing on the reinforced surface. Utilizing the reflective effect of the shielding wall 12 to form the secondary impact achieves supplementary coverage of the "geometric shadow area" (facing away region) that the main jet cannot directly reach, as well as smoothing the reinforced surface. This further solves the problem of blind spots in the processing of complex surfaces by unidirectional jets, effectively reduces the surface roughness after reinforcement, and improves the hydrodynamic performance of the workpiece.

[0029] Detailed construction of the three-sided shielding reinforced tooling (corresponding to) Figures 11-14 ): like Figure 11 As shown, in some embodiments of the present invention, the three-sided shielding reinforcement fixture 10 is generally a semi-enclosed box structure, mainly composed of a base 11 and shielding walls 12 vertically arranged on the base. Specifically, the shielding wall 12 includes a first side plate 121, a second side plate 122 arranged opposite to each other, and a back plate 123 connecting the rear ends of the two side plates. The aforementioned side plates and the base together form a semi-enclosed receiving cavity 13 with an opening on one side. In order to recover jet energy using the principle of reflection, the inner surface of the shielding wall 12 is treated with high hardness and smoothness, configured to reflect the high-speed splashed abrasive back to the central area of ​​the semi-enclosed receiving cavity 13 at a speed that still possesses polishing kinetic energy.

[0030] like Figure 12 and Figure 13 As shown, the workpiece 30 (fir tree-shaped tenon joint structure) to be strengthened is precisely positioned in the semi-enclosed receiving cavity 13 by the tooling fixture 20. The toothed surface of the workpiece 30 to be strengthened faces the opening of the tooling, and the back of the workpiece 30 is in close contact with or near the back plate 123. The tooling fixture 20 is provided with a positioning groove 21 that is strictly adapted to the shape of the tenon root of the workpiece 30, and is fastened with bolts to ensure that the workpiece 30 does not undergo any displacement or vibration under the impact load of the high-pressure water jet. Figure 12 The red area in the diagram indicates the surface of workpiece 30 exposed to the jet attack range that needs to be strengthened.

[0031] like Figure 14 As shown in the AA cross-sectional view, in order to solve the problem of waste liquid accumulation in the semi-enclosed space, a flow guiding structure 14 is integrated below the base 11. In this embodiment, the flow guiding structure 14 is manifested as an inclined flow channel 141 (or drain hole) opened below the base. This flow channel is connected to the space behind the back plate 123, and uses gravity to quickly discharge the waste liquid and waste abrasive accumulated in the semi-enclosed accommodating cavity 13, avoiding the water cushion damping effect of the rising liquid level on the jet beam, and also facilitating the recycling of abrasive.

[0032] Regarding the overall layout and intervention methods of the automated enhancement system (corresponding) Figures 15-16 ): like Figure 15 As shown, the entire strengthening method relies on an automated system. The deflecting abrasive waterjet nozzle 40 is clamped on the end flange of the six-axis robotic arm 50. The six-axis robotic arm 50 has a high degree of freedom of movement and can drive the nozzle 40 to perform multi-pose operations at the opening of the three-sided shielded strengthening fixture 10 according to the complex trajectory generated by offline programming.

[0033] Figure 16 The microscopic state of the deflecting abrasive waterjet nozzle 40 inserted into the workpiece 30 is further demonstrated. Thanks to the special curved design of the nozzle connecting pipe 42 (such as an elbow structure) and the small size of the nozzle body 41 (smaller than the opening distance between adjacent tooth grooves), the nozzle can physically extend into the narrow mortise of the workpiece 30. As shown in the figure, the nozzle body 41 has penetrated deep into the mortise without physical interference (collision) with the inner wall of the workpiece 30. This structure breaks through the "line-of-sight constraint" of traditional straight-tube nozzles, allowing the jet source to get extremely close to the surface to be strengthened deep within.

[0034] Regarding the zone-enhanced trajectory and angle control strategy (corresponding) Figures 17-20 ): This embodiment employs a partition-differentiated enhancement strategy. For example... Figure 17 and Figure 18As shown, when strengthening the "contact bearing surface area" of workpiece 30 (i.e., the straight or small curvature segments of the tooth surface shown in G and H in the figure), the control system adjusts the posture of the six-axis robotic arm 50 so that the nozzle axis forms a first angle range with the normal to the workpiece surface. In this embodiment, this angle (α1, α2) is controlled between 45° and 55° (e.g., Figure 17 (As shown in the figure, α1=45°, α2=52°). This angle setting allows the water jet to have both tangential cutting and cleaning components and normal impact components, which is beneficial for removing the surface oxide layer and introducing moderate residual compressive stress, while facilitating the abrasive particles to fly out along the reflection path after cutting.

[0035] like Figure 19 and Figure 20 As shown, when the reinforced area transitions to the "complex and narrow contour surface area" of workpiece 30 (i.e., the tooth root arc segment and tooth tip undercut shown in Figures I and J), due to the extremely limited space and high stress concentration in this area, the control system drives the nozzle 40 to deflect at a large angle. Figure 20 As shown, the angle between the nozzle axis and the normal to the workpiece surface is adjusted to the second angle range, i.e., 70°~90° (close to normal impact, as shown in the figure, α>70°). The curved structure of the deflecting nozzle allows it to bypass the obstruction of the upper tooth tip and directly and vertically impact the deep tooth root arc. This near-normal impact maximizes energy transfer efficiency, ensuring that the shadow area (dead corner) of the obstacle can obtain sufficient reinforcement strength, thereby forming a residual compressive stress layer of sufficient depth at the tooth root.

[0036] See Figure 4 This demonstrates the structural principle of a deflecting abrasive waterjet nozzle. Its connecting pipe exhibits a pronounced bending feature, causing the nozzle's axis to deflect, thus enabling it to bypass obstacles. See also... Figure 5 and Figure 7 This demonstrates the simplified structural principle of a three-sided shielded reinforced tooling. For example... Figure 5 As shown, the tooling, through its side walls and back plate, forms a semi-enclosed cavity to constrain the workpiece and abrasive; as Figure 7 As shown in the AA cross-sectional view, the bottom of the fixture has a connected discharge channel to verify the gravity-guided flow principle of waste liquid discharge. See also Figure 8 and Figure 9 This demonstrates the implementation principle of enhanced operations. For example... Figure 8 As shown, the deflecting nozzle extends into the tooling without interference; Figure 9 This further demonstrates the microscopic geometric relationship of the nozzle head penetrating deep into the mortise groove of the workpiece, verifying the physical accessibility of small-sized curved nozzles in narrow spaces.

[0037] Second aspect The present invention provides a fir tree-shaped tenon joint structure deflecting abrasive waterjet reinforcement system, the system comprising: a six-axis robotic arm 50; a deflecting abrasive waterjet nozzle 40 held by the six-axis robotic arm, the nozzle having a curved connecting pipe 42; a three-sided shielding reinforcement fixture 10 having a semi-enclosed receiving cavity 13 capable of reflecting the jet; and a controller configured to perform the method as described in the first aspect.

[0038] Example like Figure 15 As shown, this embodiment provides a method for strengthening a fir tree-shaped tenon joint structure using deflected abrasive waterjet. This method relies on an automated strengthening system consisting of a six-axis robotic arm 50, a deflected abrasive waterjet nozzle 40, and a three-sided shielding strengthening fixture 10.

[0039] The specific method and procedure are as follows: Step 1, Workpiece clamping and positioning: First, as... Figure 12 and Figure 13 As shown, the fir tree-shaped tenon joint workpiece 30 (hereinafter referred to as workpiece 30) to be strengthened is installed in the three-sided shielding strengthening fixture 10. In specific operation, the root of the tenon of workpiece 30 is embedded into the positioning groove 21 of the fixture clamp 20 set on the base 11, and locked by the pressure plate to ensure that the position of workpiece 30 remains fixed during the strengthening process. At this time, workpiece 30 is located in the semi-closed receiving cavity 13 formed by the base 11 and the shielding wall 12 (including the first side plate 121, the second side plate 122 and the back plate 123), and the tooth surface of workpiece 30 to be strengthened faces the opening side of the fixture.

[0040] Step Two: Offline Programming and Trajectory Planning: Before physical jetting, trajectory planning is first performed on the computer control terminal. The 3D CAD models of the workpiece 30 and the deflecting abrasive waterjet nozzle 40 are imported into trajectory planning software (such as RobotStudio). Figures 1 to 3 as well as Figures 17 to 20 As shown, the software logically divides the area to be strengthened into two categories based on the tooth profile features of workpiece 30: the contact bearing surface area (e.g., Figure 2 and Figure 18 The flat or slightly curved segments shown); complex and narrow contour areas (such as...) Figure 3 and Figure 19 (The tooth root arc segment and tooth tip arc segment are shown). Subsequently, the software generates motion code for the six-axis robotic arm 50 and performs virtual collision detection based on the geometry of the nozzle body 41 to ensure that the nozzle does not interfere with the inner wall of the workpiece when it extends into the tooth groove of the workpiece 30.

[0041] Step 3, Nozzle attitude adjustment and intervention: such as Figure 15As shown, the six-axis robotic arm 50 is activated, driving the deflecting abrasive waterjet nozzle 40 held at its end to move to the front of the opening of the three-sided shielding reinforcement fixture 10. Because the deflecting abrasive waterjet nozzle 40 has a curved connecting pipe 42 (such as... Figure 10 As shown, the robotic arm 50 adjusts its posture so that the shorter nozzle body 41 can physically extend into the semi-enclosed receiving cavity 13 and further probe into the narrow gap between the adjacent tooth grooves of the workpiece 30. During this process, the distance between the nozzle body 41 and the surface of the workpiece 30 is maintained at a set target distance (4 mm in this embodiment) through the coordinate control of the robotic arm.

[0042] Step 4, Differentiated Enhancement Operation: Activate the high-pressure water jet system, adjust the jet pressure to the range of 180~220MPa, and start the abrasive supply. The six-axis robotic arm 50 drives the deflecting abrasive water jet nozzle 40 to move along a preset trajectory, executing the following differentiated enhancement strategy: For the contact load-bearing surface area ( Figure 18 State): Control the posture of the robotic arm 50 so that the nozzle axis forms a small angle α1 with the surface normal of the workpiece 30 (in this embodiment, it is controlled between 45° and 55°). This angle is beneficial for removing the surface oxide layer using the tangential component of the water jet, while introducing compressive stress through the normal component.

[0043] For complex and narrow contour areas ( Figure 19 (Status): When the nozzle moves to the root arc of the tooth, the robotic arm 50 quickly adjusts its posture, increasing the spray angle to maintain the angle α2 between the nozzle axis and the normal to the surface of the workpiece 30 at 70° or higher (preferably close to 90° normal impact). Figure 16 and Figure 19 As shown in the partial cross-section, thanks to the curved design of the connecting tube 42, the nozzle body 41 can "bypass" the obstruction of the upper tooth tip and directly and vertically impact the deep tooth root arc, eliminating the "jet shadow area".

[0044] Step 5, Abrasive Recovery and Environmental Control: Throughout the strengthening process, the splashed abrasive and waste liquid generated after the high-speed jet impacts the workpiece 30 are confined within the semi-enclosed containment cavity 13. For example... Figure 6 As shown, some of the splashed abrasive impacts the inner surface of the shielding wall 12, which has undergone high-hardness and smoothing treatment, and is reflected, using residual kinetic energy to make a secondary impact on the back area of ​​the workpiece 30, thus playing a role in auxiliary cleaning and micro-forging. Finally, the waste liquid and waste abrasive converge under the action of gravity to the guide structure 14 (inclined flow channel 141) below the base 11 and are discharged to the external recycling system, avoiding the buffering interference of waste liquid accumulation on the jet energy.

[0045] These are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. Furthermore, specific examples have been used in the specification to illustrate the principles and implementation methods of the present invention. The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention, and the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for strengthening abrasive waterjet with a fir tree-shaped tenon joint structure, characterized in that, The method uses a deflecting abrasive water jet nozzle (40) and a three-sided shielding reinforcement fixture (10) to strengthen the surface of the workpiece (30); The method includes the following steps: Step S1: Workpiece clamping; The fir tree-shaped tenon joint structure workpiece (30) to be reinforced is fixed in the three-sided shielding reinforcement fixture (10); The three-sided shielding reinforcement fixture (10) includes a base (11) and a shielding wall (12) set on the base (11), the shielding wall (12) and the base (11) together form a semi-closed receiving cavity (13) with one side open; The workpiece (30) is located in the semi-closed receiving cavity (13); Step S2: Trajectory planning; Based on the tooth profile features of the workpiece (30), the area to be strengthened is divided into a contact bearing surface area and a complex and narrow profile surface area; Step S3: Nozzle attitude adjustment; control the deflecting abrasive water jet nozzle (40) to extend from the opening into the semi-closed receiving cavity (13); Step S4: Strengthening operation; control the deflecting abrasive water jet nozzle (40) to move along the area to be strengthened and spray abrasive water jet; wherein, when strengthening the contact bearing surface area, the angle between the nozzle axis and the normal of the workpiece (30) surface is controlled to be a first angle range; when strengthening the complex narrow contour surface area, the angle between the nozzle axis and the normal of the workpiece (30) surface is controlled to be a second angle range; the lower limit of the second angle range is greater than the upper limit of the first angle range.

2. The strengthening method as described in claim 1, characterized in that, The deflecting abrasive water jet nozzle (40) includes a nozzle body (41) and a connecting pipe (42). The connecting pipe (42) has a curved section, such that the axis of the nozzle body (41) and the axis of the input end of the connecting pipe (42) are set at a fixed angle. The length of the nozzle body (41) is smaller than the opening distance between adjacent tooth grooves of the fir tree-shaped tenon joint structure, and is configured to extend into the tooth groove.

3. The strengthening method as described in claim 1, characterized in that, The first angle range is 45° to 55°; and / or, the second angle range is 70° to 90°.

4. The strengthening method as described in claim 1, characterized in that, The shielding wall (12) of the three-sided shielding reinforcement fixture (10) includes a first side plate (121) and a second side plate (122) arranged opposite to each other, and a back plate (123) connecting the back of the first side plate (121) and the second side plate (122). The inner surfaces of the first side plate (121), the second side plate (122) and the back plate (123) are all high-hardness smooth surfaces, configured to reflect the splashed abrasive back to the surface of the workpiece (30) at a speed that still has polishing kinetic energy.

5. The strengthening method as described in claim 4, characterized in that, The three-sided shielding reinforcement fixture (10) also includes a fixture clamp (20), which is disposed on the base (11) and located in the semi-enclosed receiving cavity (13); The tooling fixture (20) is provided with a positioning groove (21) that is adapted to the tenon shape of the workpiece (30) to limit the displacement of the workpiece (30) and to make the tooth surface to be strengthened of the workpiece (30) face the opening.

6. The strengthening method as described in claim 1, characterized in that, The three-sided shielding reinforcement tooling (10) is also provided with a flow guiding structure (14), which is configured to discharge the waste liquid and waste abrasive material accumulated in the semi-closed accommodating cavity (13); The flow guiding structure (14) includes an inclined flow channel (141) or a drain hole located below the base (11).

7. The strengthening method as described in claim 1, characterized in that, In step S4, the deflecting abrasive water jet nozzle (40) is held and driven by a six-axis robotic arm (50); The movement trajectory of the deflecting abrasive water jet nozzle (40) is generated by offline programming, which is based on the three-dimensional CAD model of the workpiece (30), eliminating non-reinforced areas and combining the geometric dimensions of the nozzle body (41) for collision detection.

8. The strengthening method as described in claim 1, characterized in that, The parameters of the enhanced operation method include: jet pressure 180~220MPa, target distance 3.5~5.5mm, and nozzle moving speed 8~12mm / s; The complex and narrow contour area includes the root arc segment and tip arc segment of the fir tree-shaped tenon joint structure, and the contact bearing surface area includes the straight section sidewall of the fir tree-shaped tenon joint structure.

9. The strengthening method as described in claim 4, characterized in that, The abrasive water jet forms a primary impact upon contact with the surface of the workpiece (30), and a secondary impact is formed by reflection through the shielding wall (12). The secondary impact covers the area of ​​the workpiece (30) facing away from the main jet direction or performs secondary smoothing on the reinforced surface.

10. A fir-tree-shaped tenon joint structure deflecting abrasive waterjet reinforcement system, characterized in that, The system includes: Six-axis robotic arm (50); A deflecting abrasive water jet nozzle (40) held by the six-axis robotic arm, the nozzle having a curved section connecting pipe (42). The three-sided shielding reinforced tooling (10) has a semi-enclosed receiving cavity (13) capable of reflecting the jet. A controller configured to perform the method as described in any one of claims 1 to 9.

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