Planetary wheel single station forging method and device

Abstract

The present application relates to the technical field of planetary gear single station forging, and particularly relates to a planetary gear single station forging forming method and device, the method comprising: determining whether the radial deformation of the upsetting blank is uniform based on a radial deformation characteristic value, and under the condition that the radial deformation of the upsetting blank is determined to be non-uniform, determining the total pressure of the adjusting punch based on an expansion rate, or adjusting the downward speed of the adjusting punch; determining whether the axial deformation of the upsetting blank is uniform based on a second axial deformation characteristic value, and under the condition that the axial deformation is determined to be non-uniform, adjusting the holding time of the final stage based on an axial deformation difference value to obtain a punched blank; optimizing a pressure adjustment coefficient or a speed adjustment coefficient according to batch fluctuation values of defect characteristic parameters; the device comprises a mechanical arm, a punching mechanism, a data acquisition module and a stamping control module. The present application improves the machining quality of the planetary gear single station.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of single-station forging of planetary gears, and in particular to a single-station forging forming method and device for planetary gears. BACKGROUND

[0002] In the field of wind power equipment manufacturing, the performance of the megawatt wind power gear box planetary gear as a key transmission component directly affects the stability and power generation efficiency of the wind power equipment. Currently, single-station forging is an important process for manufacturing planetary gears, but this process faces many challenges in forming quality. On the one hand, in the traditional forging process, the metal flow of the blank in the single station is difficult to accurately control, resulting in insufficient filling of the tooth profile part of the planetary gear, problems such as insufficient tooth tip fullness and irregular tooth root fillet, and seriously affecting the meshing accuracy and load capacity of the gear. On the other hand, during the single-station forging process, the temperature field and stress field are unevenly distributed, which easily causes internal defects in the planetary gear, such as micro-cracks and porosity, greatly reducing the fatigue life of the planetary gear. In addition, the limitations of die design and manufacturing precision make the blank poorly fit with the die during forging, further exacerbating the deterioration of forming quality, resulting in a high scrap rate. Improving the single-station forming quality of planetary gears and optimizing the existing forging process and equipment have become key problems to be solved.

[0003] Chinese Patent Application Publication No. CN114700702A discloses a forming process for high-speed hot upsetting of planetary half shaft gears, which includes the following specific steps: blanking, induction heating, shearing, blank shaping, station upsetting, and final forming. This process solves the defects that may be caused by the burrs, collapse angle, cutter marks, and non-parallel end faces of the cut end face, as well as the deformation of the outer circle, during the hot forging of umbrella gears.

[0004] The existing technology also has the following problems: in the single-station machining process of punching the upsetting blank to form a punched blank, the radial deformation and transverse deformation of the upsetting blank are not monitored and controlled, resulting in poor internal organizational integrity of the punched blank, and thus poor single-station machining quality of the planetary gear. SUMMARY

[0005] To overcome the problem of poor internal organizational integrity of the punched blank due to the lack of monitoring and control of the radial deformation and transverse deformation of the upsetting blank in the existing technology, and thus poor single-station machining quality of the planetary gear, the present application provides a single-station forging forming method and device for planetary gears.

[0006] To achieve the above-mentioned purpose, on the one hand, the present application provides a single-station forging forming method for planetary gears, comprising:

[0007] A plurality of positioning points are arranged on the upper surface of the upsetting blank, and a plurality of image information of the upper surface in the piercing process is obtained, wherein the piercing process includes an early stage, a middle stage and a late stage;

[0008] A radial deformation characteristic value of the plurality of positioning points, an expansion rate of the outer edge of the upsetting blank and a first axial deformation characteristic value of the upsetting blank are determined based on the image information of the early stage, so as to determine whether the radial deformation of the upsetting blank is uniform based on the radial deformation characteristic value, and under the condition that the radial deformation of the upsetting blank is determined to be non-uniform, the total pressure of the punch is adjusted by a pressure adjustment coefficient according to the expansion rate, or the downward speed of the punch is adjusted by a speed adjustment coefficient;

[0009] A second axial deformation characteristic value of the upsetting blank is determined based on the image information of the middle stage, so as to determine whether the axial deformation of the upsetting blank is uniform based on the second axial deformation characteristic value, and under the condition that the axial deformation is determined to be non-uniform, the piercing blank is obtained by adjusting the pressure holding time length of the late stage based on the axial deformation difference value of the first axial deformation characteristic value and the second axial deformation characteristic value;

[0010] A defect characteristic parameter of the fracture zone on the piercing section of the piercing blank of a plurality of production batches is obtained, so as to optimize the pressure adjustment coefficient or the speed adjustment coefficient according to the batch fluctuation value of the defect characteristic parameter.

[0011] Further, the determination process of the radial deformation characteristic value includes:

[0012] A plurality of displacement distances of the plurality of positioning points along the radial direction are determined according to the image information;

[0013] The standard deviation of the plurality of displacement distances is determined as the radial deformation characteristic value.

[0014] Further, the process of determining whether the radial deformation of the upsetting blank is uniform based on the radial deformation characteristic value includes:

[0015] The radial deformation characteristic value is compared with a preset radial deformation characteristic value;

[0016] It is determined that the radial deformation of the upsetting blank is non-uniform based on the comparison result that the radial deformation characteristic value is greater than the preset radial deformation characteristic value.

[0017] Further, under the condition that the radial deformation of the upsetting blank is determined to be non-uniform, the process of adjusting the total pressure of the punch according to the expansion rate includes:

[0018] The expansion rate is compared with a preset rate;

[0019] It is determined to increase the total pressure based on the comparison result that the expansion rate is less than the preset rate.

[0020] wherein a plurality of pressure adjustment coefficients are set based on a first rate difference between the preset rate and the expansion rate, so as to increase the total pressure according to the plurality of pressure adjustment coefficients.

[0021] Further, in the case that the radial deformation of the upsetting blank is determined to be uneven, the process of adjusting the downward speed of the punch according to the expansion rate comprises:

[0022] comparing the expansion rate with a preset rate;

[0023] determining to decrease the downward speed based on the comparison result that the expansion rate is greater than the preset rate;

[0024] wherein a plurality of speed adjustment coefficients are set based on a second rate difference between the expansion rate and the preset rate, so as to decrease the downward speed according to the plurality of speed adjustment coefficients.

[0025] Further, the process of determining the axial deformation representation value comprises:

[0026] determining an initial surface position of the upper surface of the upsetting blank and real-time surface positions at different stages in the stamping process;

[0027] aligning the initial surface position and the real-time surface positions with the geometric center as the reference to determine a plurality of vertical distances;

[0028] determining a standard deviation of the plurality of vertical distances as the axial deformation representation value;

[0029] wherein the first axial deformation representation value is the axial deformation representation value of the initial surface position and the real-time surface position at the early stage, and the second axial deformation representation value is the axial deformation representation value of the initial surface position and the real-time surface position at the middle stage.

[0030] Further, the process of determining whether the axial deformation of the upsetting blank is uniform based on the second axial deformation representation value comprises:

[0031] comparing the second axial deformation representation value with a preset axial deformation representation value;

[0032] determining that the axial deformation of the upsetting blank is uneven based on the comparison result that the second axial deformation representation value is greater than the preset axial deformation representation value.

[0033] Further, the process of adjusting the holding time at the late stage according to the axial deformation difference value comprises:

[0034] comparing the axial deformation difference value with a preset deformation difference value;

[0035] Set a plurality of time length adjustment coefficients based on the comparison result of the axial deformation difference value and the preset deformation difference value, to increase the pressure maintaining time length based on the plurality of time length adjustment coefficients.

[0036] Further, the process of determining to optimize the pressure adjustment coefficient or the speed adjustment coefficient based on the batch fluctuation value comprises:

[0037] Comparing the batch fluctuation value with a preset fluctuation value;

[0038] Determining to optimize the pressure adjustment coefficient or the speed adjustment coefficient based on the comparison result that the batch fluctuation value is greater than the preset fluctuation value;

[0039] Wherein, a plurality of pressure correction coefficients or a plurality of speed correction coefficients are set based on the fluctuation difference value of the batch fluctuation value and the preset fluctuation value, to optimize the pressure adjustment coefficient by the pressure correction coefficient, or to optimize the speed adjustment coefficient by the speed correction coefficient.

[0040] In another aspect, the present application also provides a planetary wheel single station forging forming device, comprising:

[0041] A mechanical arm;

[0042] A punching mechanism, comprising a punch sleeve movably connected with the mechanical arm, a punch movably connected with the punch sleeve, a die disposed below the punch and aligned with the center of the punch for placing a upsetting blank, a die pad disposed in the die, and a die fixing plate movably connected with the die and the die pad at the bottom of the die;

[0043] A data acquisition module, comprising an image collector disposed on the side of the mechanical arm facing the die;

[0044] A stamping control module connected with the data acquisition module, comprising,

[0045] A radial deformation determination unit for determining radial deformation representation values of a plurality of positioning points, an expansion rate of the outer edge of the upsetting blank, and a first axial deformation representation value of the upsetting blank based on image information of the early stage, to determine whether the radial deformation of the upsetting blank is uniform based on the radial deformation representation values, and to determine to adjust the total pressure of the punch by a pressure adjustment coefficient or to adjust the downward speed of the punch by a speed adjustment coefficient according to the expansion rate on the condition that the radial deformation of the upsetting blank is not uniform;

[0046] an axial deformation determination unit configured to determine a second axial deformation representation value of the upsetting blank based on the image information of the intermediate stage, to determine whether the axial deformation of the upsetting blank is uniform based on the second axial deformation representation value, and to adjust the holding time of the final stage of the piercing blank based on an axial deformation difference value between the first axial deformation representation value and the second axial deformation representation value under the condition that the axial deformation is determined to be non-uniform;

[0047] a correction unit configured to optimize the pressure adjustment coefficient or the speed adjustment coefficient based on batch fluctuation values of the defect representation parameters of the fracture zone on the piercing section of the piercing blank of a plurality of production batches.

[0048] Compared with the prior art, the present application has the beneficial effects that the present application sets a plurality of positioning points on the surface of the upsetting blank, determines the radial deformation representation value according to the displacement distance of each positioning point during the piercing process of the upsetting blank, determines whether the radial deformation of the upsetting blank in the early stage is uniform, and adjusts the total pressure of the punch or the downward speed of the punch under the condition that the radial deformation of the early stage is determined to be non-uniform, so as to correct the radial deformation uniformity of the upsetting blank in the remaining piercing process; the image information of the intermediate stage is obtained to determine the second axial deformation representation value, whether the axial deformation of the upsetting blank in the piercing process is uniform is determined according to the axial deformation representation value, and the holding time of the final stage is increased under the condition that the axial deformation is determined to be non-uniform, so as to improve the axial deformation uniformity; at the same time, the adjustment coefficient is optimized according to the batch fluctuation value of the historical production batch, so as to further improve the radial deformation uniformity and the axial deformation uniformity of the upsetting blank in the piercing process, thereby improving the internal integrity of the piercing blank and improving the machining quality of the planetary gear single station.

[0049] Further, under the condition of determining the non-uniform radial deformation, the total pressure of the punch or the downward speed of the punch is determined according to the expansion rate, and the non-uniformity of the radial deformation is further intensified under the condition of a larger expansion rate, and the downward speed of the punch needs to be appropriately reduced, and the total pressure of the punch needs to be appropriately increased under the condition of a smaller expansion rate, the expansion rate is essentially the flow speed of the metal along the radial direction, and directly reflects the activity of plastic deformation of the material, if the expansion rate is too large, the area with small flow resistance rapidly expands outward due to inertia, and the area with large flow resistance lags behind, so that the deformation amounts at different positions in the radial direction are significantly different, the downward speed of the punch is one of the power sources for driving the metal flow, the faster the speed, the stronger the extrusion impact on the upsetting blank in unit time, and the flow speed difference between different areas is further enlarged, therefore, the downward speed of the punch is reduced, the impact of the metal flow is reduced, sufficient time is left for the area with large flow resistance to uniformly supplement the material, the non-uniform trend of the faster and the slower is relieved, and thus the radial deformation deviation is corrected, when the expansion rate is small, the root cause of the non-uniform radial deformation is insufficient flow driving force, the low expansion rate means that the power of the plastic flow of the metal is insufficient, at this time, the material is difficult to uniformly expand in the radial direction, and local stagnation is prone to occur, the total pressure of the punch is the core energy source for driving the material flow, the greater the pressure, the higher the hydrostatic pressure borne by the upsetting blank, and the stronger the plastic deformation capacity of the material, so that the permeable flow of the metal in the radial direction is more sufficient, therefore, the total pressure of the punch is increased, the extrusion on the upsetting blank is strengthened, the metal is supplemented to the area with slow flow, the thickness deviation caused by insufficient power is eliminated, the uniformity of the radial deformation is corrected, and thus the internal integrity of the punched blank is further improved, and the machining quality of the planetary gear single station is improved.

[0050] Further, under the condition of determining the non-uniform radial deformation, the total pressure of the punch or the downward speed of the punch is determined according to the expansion rate, and the non-uniformity of the radial deformation is further intensified under the condition of a larger expansion rate, and the downward speed of the punch needs to be appropriately reduced, and the total pressure of the punch needs to be appropriately increased under the condition of a smaller expansion rate, the expansion rate is essentially the flow speed of the metal along the radial direction, and directly reflects the activity of plastic deformation of the material, if the expansion rate is too large, the area with small flow resistance rapidly expands outward due to inertia, and the area with large flow resistance lags behind, so that the deformation amounts at different positions in the radial direction are significantly different, the downward speed of the punch is one of the power sources for driving the metal flow, the faster the speed, the stronger the extrusion impact on the upsetting blank in unit time, and the flow speed difference between different areas is further enlarged, therefore, the downward speed of the punch is reduced, the impact of the metal flow is reduced, sufficient time is left for the area with large flow resistance to uniformly supplement the material, the non-uniform trend of the faster and the slower is relieved, and thus the radial deformation deviation is corrected, when the expansion rate is small, the root cause of the non-uniform radial deformation is insufficient flow driving force, the low expansion rate means that the power of the plastic flow of the metal is insufficient, at this time, the material is difficult to uniformly expand in the radial direction, and local stagnation is prone to occur, the total pressure of the punch is the core energy source for driving the material flow, the greater the pressure, the higher the hydrostatic pressure borne by the upsetting blank, and the stronger the plastic deformation capacity of the material, so that the permeable flow of the metal in the radial direction is more sufficient, therefore, the total pressure of the punch is increased, the extrusion on the upsetting blank is strengthened, the metal is supplemented to the area with slow flow, the thickness deviation caused by insufficient power is eliminated, the uniformity of the radial deformation is corrected, and thus the internal integrity of the punched blank is further improved, and the machining quality of the planetary gear single station is improved. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 The flowchart of the planetary gear single-station forging forming method of the embodiment of the present application is shown in the figure.

[0052] Figure 2 The flowchart of determining whether the radial deformation of the upsetting blank is uniform or not of the embodiment of the present application is shown in the figure.

[0053] Figure 3 The flowchart of determining whether the axial deformation of the upsetting blank is uniform or not of the embodiment of the present application is shown in the figure.

[0054] Figure 4 The structural schematic diagram of the planetary gear single-station forging forming device of the embodiment of the present application is shown in the figure.

[0055] In the figure: 1, punch sleeve, 2, punch, 3, die, 4, die pad, 5, die fixing plate, 6, upsetting blank, 7, image collector, 8, mechanical arm. DETAILED DESCRIPTION

[0056] In order to make the objects and advantages of the present application clearer, the following further describes the present application with reference to examples; it should be understood that the specific examples described herein are merely used to explain the present application and do not limit the present application.

[0057] The preferred embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the present application and are not intended to limit the protection scope of the present application.

[0058] It should be noted that, in the description of the present application, the terms indicating the direction or positional relationship such as 'upper', 'lower', 'left', 'right', 'inner', 'outer' and the like are based on the direction or positional relationship shown in the drawings, which is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0059] In addition, it should also be noted that, in the description of the present application, unless otherwise explicitly specified and limited, the terms'mounting', 'connection', 'connecting' should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements. Those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific circumstances.

[0060] Please refer to Figures 1-3 shown, Figure 1 the flowchart of the planetary gear single-station forging forming method of the embodiment of the present application; Figure 2 the flowchart of determining whether the radial deformation of the upsetting blank is uniform or not of the embodiment of the present application; Figure 3 the flowchart of determining whether the axial deformation of the upsetting blank is uniform or not of the embodiment of the present application.

[0061] The planetary gear single-station forging forming method of the embodiment of the present application comprises:

[0062] Step S1, a plurality of positioning points are arranged on the upper surface of the upsetting blank, and a plurality of image information of the upper surface in the punching process is obtained, wherein the punching process comprises an early stage, a middle stage and a late stage;

[0063] In step S2, a radial deformation characteristic value of the positioning points, an expansion rate of the outer edge of the upsetting blank, and a first axial deformation characteristic value of the upsetting blank are determined based on the image information of the early stage, so as to determine whether the radial deformation of the upsetting blank is uniform based on the radial deformation characteristic value, and if the radial deformation of the upsetting blank is determined to be non-uniform, the total pressure of the punch is adjusted by a pressure adjustment coefficient or the downward speed of the punch is adjusted by a speed adjustment coefficient according to the expansion rate;

[0064] In step S3, a second axial deformation characteristic value of the upsetting blank is determined based on the image information of the middle stage, so as to determine whether the axial deformation of the upsetting blank is uniform based on the second axial deformation characteristic value, and if the axial deformation is determined to be non-uniform, the piercing blank is obtained by adjusting the holding pressure time length of the late stage based on the axial deformation difference between the first axial deformation characteristic value and the second axial deformation characteristic value.

[0065] In step S4, a defect characteristic parameter of the fracture zone on the piercing section of the piercing blank of a plurality of production batches is obtained, so as to optimize the pressure adjustment coefficient or the speed adjustment coefficient according to the batch fluctuation value of the defect characteristic parameter.

[0066] Specifically, the manufacturing process of the planetary gear includes cutting, heating, upsetting, upsetting, one-time piercing die forging, machining and removing excess parts, and the embodiment of the present application is only for the one-time piercing die forging process of the upsetting blank. The upsetting blank is a solid pie-shaped cake with a diameter slightly smaller than the outer diameter of the final forging and a height slightly higher than the thickness of the final forging. In the piercing process, the punch applies axial pressure to the center of the upsetting blank, forcing the center metal to flow radially, and finally forming a through hole matching the size of the punch. The radially flowing metal increases the outer diameter of the blank, while the axial height decreases due to the extrusion and extension of the metal.

[0067] Specifically, the positioning points are arranged on the upper surface of the upsetting blank by the following methods: a high-temperature-resistant material such as tungsten, molybdenum, aluminum oxide and zirconium oxide is adhered to the upper surface of the upsetting blank by physical spot welding, plasma spraying or laser cladding to form the positioning points. The positioning points can be arranged at a preset angle uniformly along a circle with the geometric center of the upsetting blank as the center and a preset distance (greater than the diameter of the punch) as the diameter. For example, for an upsetting blank with a diameter of 300 mm, the punch has a diameter of 50 mm, and six positioning points can be arranged at an angle interval of 60° along a circle with a diameter of 100 mm.

[0068] Specifically, the device for obtaining the image information of the upper surface of the upsetting blank in the piercing process is an image collector, such as a near-infrared enhanced industrial camera with the model of SAP-2501NIR-GE, and the specific model is not limited.

[0069] Specifically, the piercing process can be divided into several stages according to the thickness of the blank, for example, the early stage is that the punch contacts the upset blank to the piercing depth reaches 1 / 3 of the thickness of the upset blank, the middle stage is that the piercing depth is from 1 / 3 to 2 / 3 of the thickness of the upset blank, and the final stage is that the piercing depth is from 2 / 3 of the thickness of the upset blank to the completion of the piercing, which is not limited in particular.

[0070] Specifically, the determination process of the radial deformation representation value includes:

[0071] According to the image information, the displacement distances of the positioning points in the radial direction are determined.

[0072] The standard deviation of the displacement distances is determined as the radial deformation representation value.

[0073] Specifically, after the images obtained by the industrial camera are preprocessed such as graying and denoising, the displacement distances of the positioning points on the surface of the blank in adjacent frames are compared, and the displacement distances of the points are calculated.

[0074] Specifically, the process of determining whether the radial deformation of the upset blank is uniform based on the radial deformation representation value includes:

[0075] The radial deformation representation value is compared with a preset radial deformation representation value.

[0076] Based on the comparison result that the radial deformation representation value is greater than the preset radial deformation representation value, it is determined that the radial deformation of the upset blank is not uniform.

[0077] Based on the comparison result that the radial deformation representation value is less than or equal to the preset radial deformation representation value, it is determined that the radial deformation of the upset blank is uniform.

[0078] Specifically, the value range of the preset radial deformation value is set to [2mm, 5mm], and the embodiment of the present application preferably is 3mm.

[0079] It can be understood that under the condition that the radial deformation of the upset blank is uniform, the displacement distances of the positioning points should be similar in the radial direction, the dispersion degree of each displacement distance is low, and the corresponding standard deviation value is small. When the radial deformation of the upset blank is not uniform, the dispersion degree of each displacement distance is high, and the standard deviation is large.

[0080] Specifically, under the condition that it is determined that the radial deformation of the upset blank is not uniform, the process of adjusting the total pressure of the punch according to the expansion rate includes:

[0081] The expansion rate is compared with a preset rate.

[0082] Based on the comparison result that the expansion rate is less than the preset rate, it is determined to increase the total pressure.

[0083] The first rate difference between the preset rate and the expansion rate is used to set a plurality of pressure adjustment coefficients, and the total pressure is increased according to the plurality of pressure adjustment coefficients.

[0084] Specifically, the first rate difference is compared with a preset difference value;

[0085] Based on the comparison result that the first rate difference is greater than the preset difference value, the total pressure is increased by a first pressure adjustment coefficient;

[0086] Based on the comparison result that the first rate difference is less than or equal to the preset difference value, the total pressure is increased by a second pressure adjustment coefficient.

[0087] Specifically, the expansion rate is the average displacement increment of the outer edge of the upset blank per unit time in the radial direction.

[0088] Specifically, the preset rate is set in the range of [5mm / s, 20mm / s], and the embodiment of the application is preferably 10mm / s; the preset difference value is set in the range of [2mm / s, 4mm / s], and the embodiment of the application is preferably 3mm / s; the first pressure adjustment coefficient is set in the range of [1.05, 1.08], and the embodiment of the application is preferably 1.06; and the second pressure adjustment coefficient is set in the range of [1.01, 1.04], and the embodiment of the application is preferably 1.03.

[0089] Specifically, under the condition that the radial deformation of the upset blank is uneven, the process of adjusting the downward speed of the punch according to the expansion rate comprises:

[0090] The expansion rate is compared with a preset rate;

[0091] Based on the comparison result that the expansion rate is greater than the preset rate, the downward speed is reduced;

[0092] The second rate difference between the expansion rate and the preset rate is used to set a plurality of speed adjustment coefficients, and the downward speed is reduced according to the plurality of speed adjustment coefficients.

[0093] Specifically, the second rate difference is compared with a preset difference value;

[0094] Based on the comparison result that the second rate difference is greater than the preset difference value, the downward speed is reduced by a first speed adjustment coefficient;

[0095] Based on the comparison result that the second rate difference is less than or equal to the preset difference value, the downward speed is reduced by a second speed adjustment coefficient.

[0096] Specifically, the first speed adjustment coefficient is set in the range of [0.92, 0.95], and the embodiment of the application preferably is 0.93; the second speed adjustment coefficient is set in the range of [0.96, 0.99], and the embodiment of the application preferably is 0.97.

[0097] It can be understood that the excessive expansion rate of the outer edge of the upsetting blank will cause local difference amplification, so that the downward speed of the punch is appropriately reduced, the deformation time of the metal is prolonged, the local resistance of the die pad has more sufficient time to guide the uniform flow of the metal, thereby increasing the radial deformation uniformity of the upsetting blank; under the condition that the expansion rate of the outer edge of the upsetting blank is small, the total pressure of the punch is appropriately increased, the overall driving force is improved, and the low resistance design of the die pad in the lag area is matched, so as to promote the flow of the metal to the area, and at the same time, the fast flow area can offset the additional driving force brought by the increase of the total pressure due to the high resistance design of the die pad, thereby correcting the deformation uniformity of the upsetting blank during the stamping process.

[0098] Specifically, the die pad is a die inner member directly in contact with the blank, and the local physical properties such as thickness and hardness of the die pad will significantly affect the deformation resistance of different regions of the upsetting blank, thereby guiding the metal flow direction.

[0099] Specifically, the determination process of the axial deformation representation value includes:

[0100] The initial surface position of the upper surface of the upsetting blank and the real-time surface position at different stages in the stamping process are determined.

[0101] The initial surface position and the real-time surface position are aligned with the geometric center as the reference to determine a plurality of vertical distances.

[0102] The standard deviation of a plurality of vertical distances is determined as the axial deformation representation value.

[0103] Specifically, the first axial deformation representation value is the axial deformation representation value of the initial surface position and the real-time surface position at the early stage, and the second axial deformation representation value is the axial deformation representation value of the initial surface position and the real-time surface position at the middle stage.

[0104] Specifically, the process of determining whether the axial deformation of the upsetting blank is uniform based on the second axial deformation representation value includes:

[0105] The second axial deformation representation value is compared with a preset axial deformation representation value.

[0106] Based on the comparison result that the second axial deformation representation value is greater than the preset axial deformation representation value, it is determined that the axial deformation of the upsetting blank is not uniform.

[0107] determine the axial deformation uniformity of the upsetting blank based on a comparison result of the second axial deformation representation value and the preset axial deformation representation value.

[0108] Specifically, the preset axial deformation representation value is set to [0.4mm, 0.8mm], and the embodiment of the application preferably 0.6mm.

[0109] Specifically, in the stamping process of the upsetting blank, the radial flow in the early stage is the main deformation direction, and the metal tends to flow to the radial area with small resistance. If the blank edge is not in close contact with the die, the radial flow resistance is small, and the edge metal flows more to the radial direction. The center is directly compressed by the punch, and the axial compression is more significant. The thickness reduction rate of the outer edge will be lower than that of the center area, forming a situation of thin center and thick edge, resulting in poor axial deformation uniformity in the early stage. After entering the middle stage, the upsetting blank has completed most of the radial deformation, and the contact mode with the punch and die changes from local contact to full adhesion. The axial pressure is more evenly transmitted to the full surface of the upsetting blank through the die interface, and the local concentration phenomenon of pressure distribution is weakened. The driving force for thickness reduction is more balanced. At the same time, the radial constraint of the metal by the die inner wall and the die cushion block is enhanced, and the metal is more difficult to escape from axial compression by preferential radial flow, and is forced to be more uniformly thinned in the axial direction. In addition, the die cushion block can exert additional resistance on the local thick area by adjusting its supporting force, forcing the metal in this area to be more fully compressed in the axial direction, further improving the thickness uniformity of the upsetting blank. The smaller the axial deformation representation value, the more uniform the thickness of the upsetting blank, and the more uniform the axial deformation.

[0110] Specifically, the process of adjusting the holding time length of the final stage according to the axial deformation difference value includes:

[0111] comparing the axial deformation difference value with a preset deformation difference value;

[0112] Based on the comparison result of the axial deformation difference value and the preset deformation difference value, a plurality of time length adjustment coefficients are set to increase the holding time length based on a plurality of time length adjustment coefficients.

[0113] Specifically, based on the comparison result that the axial deformation difference value is greater than the preset deformation difference value, the first time length adjustment coefficient is determined to increase the holding time length;

[0114] Based on the comparison result that the axial deformation difference value is less than or equal to the preset deformation difference value, the second time length adjustment coefficient is determined to increase the holding time length.

[0115] Specifically, the preset deformation difference value is set to [0.05mm, 0.2mm], and the embodiment of the present application preferably 0.1mm; the value range of the second time length adjustment coefficient is set to [1.2, 1.4], and the embodiment of the present application preferably 1.25; the value range of the first time length adjustment coefficient is set to [1.41, 1.6], and the embodiment of the present application preferably 1.45.

[0116] It can be understood that the greater the axial deformation difference value represents the better thickness uniformity of the intermediate stage upsetting blank, and the shorter the required increased holding time.

[0117] Specifically, under the condition of determining the axial deformation non-uniformity of the upsetting blank, the holding time of the final stage can be appropriately increased to increase the axial deformation uniformity. For the upsetting blank of the high-strength and large-size planetary gear, the plastic deformation of the metal not only depends on the external force, but also depends on the deformation time. The plastic deformation mechanisms such as metal internal atom diffusion and grain boundary sliding need a certain time to fully activate. The core of the final holding stage is: under the premise of stable punch position, by continuously maintaining the pressure, a supplementary flow window time is provided for the areas that are not fully deformed in the middle stage. At the same time, after the plastic deformation of the metal, there is a tendency of elastic recovery, especially in the high stress area. The areas with uneven thickness often have higher residual stress. If the stamping is directly ended, the thickness deviation may be aggravated by the rebound. Therefore, the holding time is extended in the final stage, so that the residual stress can be fully released slowly under the continuous pressure, the amount of elastic recovery is reduced, and the metal can complete the final forming in a more stable stress state, ensuring that the thickness uniformity is not easily deteriorated due to rebound in the subsequent process.

[0118] Specifically, the defect characterization parameter refers to the percentage of the defect area existing on the unit area of the punching section, wherein the defects include but are not limited to dislocations, microcracks and tear edges, which are determined based on the image information of the punching section, which is a prior art and will not be described here. The batch fluctuation value of the defect characterization parameter is the standard deviation of the defect characterization parameter of each batch.

[0119] Specifically, the process of optimizing the pressure adjustment coefficient or the speed adjustment coefficient based on the batch fluctuation value includes:

[0120] Comparing the batch fluctuation value with a preset fluctuation value;

[0121] Based on the comparison result that the batch fluctuation value is greater than the preset fluctuation value, the pressure adjustment coefficient or the speed adjustment coefficient is optimized;

[0122] Based on the comparison result that the batch fluctuation value is less than or equal to the preset fluctuation value, the pressure adjustment coefficient or the speed adjustment coefficient is not optimized;

[0123] The fluctuation difference between the batch fluctuation value and the preset fluctuation value is compared.

[0124] Specifically, the fluctuation difference is compared with a preset fluctuation difference.

[0125] Based on the comparison result that the fluctuation difference is greater than the preset fluctuation difference, it is determined to reduce the pressure adjustment coefficient by a first pressure correction coefficient or to reduce the speed adjustment coefficient by a first speed correction coefficient.

[0126] Based on the comparison result that the fluctuation difference is less than or equal to the preset fluctuation difference, it is determined to reduce the pressure adjustment coefficient by a second pressure correction coefficient or to reduce the speed adjustment coefficient by a second speed correction coefficient.

[0127] Specifically, the preset fluctuation value is set in the range of [0.05%, 0.15%], and the preset fluctuation value is preferably 0.1% in the embodiment of the application; the preset fluctuation difference is set in the range of [0.02%, 0.04%], and the preset fluctuation difference is preferably 0.03% in the embodiment of the application; the first pressure correction coefficient is set in the range of [0.88, 0.93], and the first pressure correction coefficient is preferably 0.9 in the embodiment of the application; the first speed correction coefficient is set in the range of [0.85, 0.9], and the first speed correction coefficient is preferably 0.87 in the embodiment of the application; the second pressure correction coefficient is set in the range of [0.94, 0.97], and the second pressure correction coefficient is preferably 0.955 in the embodiment of the application; and the second speed correction coefficient is set in the range of [0.91, 0.95], and the second speed correction coefficient is preferably 0.925 in the embodiment of the application.

[0128] Specifically, in the punching process, the generation of defects is directly related to pressure and speed. The pressure determines the uniformity of plastic deformation of the material. Excessive pressure may cause stress concentration and form micro cracks. The speed affects the deformation rate and energy accumulation. Excessive speed will cause material flow lag, resulting in a sharp increase in local strain rate, producing brittle fracture defects. The formation of the fracture zone is accompanied by severe plastic deformation and tearing, and there are a large number of dislocations, micro cracks and grain boundary damage in the microstructure. For high-strength alloy steel materials, these defects may further develop into delamination or block, destroying the continuity of the material. The defect characteristics of the fracture zone are exponentially negatively correlated with the fatigue crack initiation life. Therefore, the total pressure of the punch or the downward speed of the punch can be optimized according to the batch stability of the defect characterization parameters of the fracture zone to improve the production quality of the punched blank.

[0129] Please refer to Figure 4 Fig. 1 is a structural schematic diagram of a planetary wheel single-station forging forming device according to an embodiment of the application.

[0130] The planet wheel single-station forging forming device comprises:

[0131] The mechanical arm 8;

[0132] The punching mechanism comprises a punch sleeve 1 movably connected with the mechanical arm 8, a punch 2 movably connected with the punch sleeve 1, a die 3 arranged below the punch 2 and aligned with the center of the punch 2 to place the upsetting blank 6, a die pad 4 arranged in the die 3, and a die fixing plate 5 movably connected with the die 3 and the die pad 4 at the bottom of the die 3;

[0133] The data acquisition module comprises an image collector 7 arranged on the side of the mechanical arm 8 facing the die 3;

[0134] The stamping control module is connected with the data acquisition module and comprises,

[0135] The radial deformation determination unit is used to determine the radial deformation characteristic values of a plurality of positioning points, the expansion rate of the outer edge of the upsetting blank 6 and the first axial deformation characteristic value of the upsetting blank 6 based on the image information of the early stage, to determine whether the radial deformation of the upsetting blank 6 is uniform based on the radial deformation characteristic values, and to adjust the total pressure of the punch 2 by a pressure adjustment coefficient or the downward speed of the punch 2 by a speed adjustment coefficient according to the expansion rate on the condition that the radial deformation of the upsetting blank 6 is determined to be non-uniform;

[0136] The axial deformation determination unit is used to determine the second axial deformation characteristic value of the upsetting blank 6 based on the image information of the middle stage, to determine whether the axial deformation of the upsetting blank 6 is uniform based on the second axial deformation characteristic value, and to adjust the holding pressure time length of the final stage based on the difference between the first axial deformation characteristic value and the second axial deformation characteristic value to obtain the punched blank on the condition that the axial deformation is determined to be non-uniform;

[0137] The correction unit is used to optimize the pressure adjustment coefficient or the speed adjustment coefficient based on the batch fluctuation value of the defect characteristic parameters of the fracture zone on the punching section of the punched blank of a plurality of production batches.

[0138] Specifically, the punching process of the upsetting blank 6 is as follows: the upsetting blank 6 is placed in the die 3, the punch sleeve 1 is placed in the groove of the mechanical arm 8, the punch 2 is inserted from below the punch sleeve 1, the pin is used to fix the punch sleeve 1 and the mechanical arm 8, the die fixing plate 5 is placed on the press turret and fixed in the middle of the turret in a mechanical fitting manner, the die pad 4 is placed in the die, the die is placed on the die fixing plate 5 in the same way, the punch 2 is pressed down to the position shown in the figure under the control of the stamping control module, and the punch 2 is pulled out to complete the punching process of the upsetting blank 6.

[0139] Specifically, the punch angle of the punch 2 is 0.4°, the punch angle refers to the inclination angle of the forming surface of the punch 2 in contact with the upsetting blank 6 relative to the axis of the upsetting blank 6, the die pad 4 is 40mm deep, and the recess is slotted.

[0140] Specifically, the punch sleeve 1 and the punch 2 are connected by a pin, which prevents the workpiece from adhering to the punch 2 and the workpiece from being taken out of the mechanical arm 8. After the pin is pulled out, the punch 2 is separated from the punch sleeve 1 and the mechanical arm 8, and the workpiece can be separated from the punch 2. Through the innovation of the die 3, the process integration is realized, the ring rolling process and the secondary punching process are cancelled, the grain flow lines of the final formed planetary gear are distributed along the tooth profile, the tensile strength of the tooth root is improved to more than 1100MPa, and the yield strength is improved to more than 930MPa.

[0141] So far, the technical solutions of the present application have been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical solutions after the changes or replacements will fall within the protection scope of the present application.

Claims

1. A planetary wheel single station swage forming method characterized by, The method comprises the following steps: a plurality of positioning points are arranged on the upper surface of the upsetting blank, and a plurality of image information of the upper surface in the punching process is obtained, wherein the punching process comprises an early stage, a middle stage and a late stage; a radial deformation characteristic value of the plurality of positioning points, an expansion rate of the outer edge of the upsetting blank and a first axial deformation characteristic value of the upsetting blank are determined based on the image information of the early stage, so as to determine whether the radial deformation of the upsetting blank is uniform based on the radial deformation characteristic value, and to adjust the total pressure of the punch by a pressure adjustment coefficient or to adjust the downward speed of the punch by a speed adjustment coefficient based on the expansion rate under the condition that the radial deformation of the upsetting blank is determined to be non-uniform; a second axial deformation characteristic value of the upsetting blank is determined based on the image information of the middle stage, so as to determine whether the axial deformation of the upsetting blank is uniform based on the second axial deformation characteristic value, and to adjust the holding pressure time length of the late stage based on the axial deformation difference value of the first axial deformation characteristic value and the second axial deformation characteristic value to obtain a punched blank under the condition that the axial deformation is determined to be non-uniform; a defect characteristic parameter of a fracture zone on the punching section of the punched blank of a plurality of production batches is obtained, so as to optimize the pressure adjustment coefficient or the speed adjustment coefficient according to the batch fluctuation value of the defect characteristic parameter.

2. The planetary wheel single station swage forming method of claim 1, wherein, The determination process of the radial deformation characteristic value comprises: a plurality of displacement distances of the plurality of positioning points along the radial direction are determined according to the image information; the standard deviation of the plurality of displacement distances is determined as the radial deformation characteristic value.

3. The planetary wheel single station swage forming method of claim 2, wherein, The process of determining whether the radial deformation of the upsetting blank is uniform based on the radial deformation characteristic value comprises: the radial deformation characteristic value is compared with a preset radial deformation characteristic value; it is determined that the radial deformation of the upsetting blank is non-uniform based on the comparison result that the radial deformation characteristic value is greater than the preset radial deformation characteristic value.

4. The planetary wheel single station swage forming method of claim 3 wherein, The process of adjusting the total pressure of the punch according to the expansion rate under the condition that the radial deformation of the upsetting blank is determined to be non-uniform comprises: the expansion rate is compared with a preset rate; it is determined to increase the total pressure based on the comparison result that the expansion rate is less than the preset rate; wherein a plurality of pressure adjustment coefficients are set based on a first rate difference value between the preset rate and the expansion rate, so as to increase the total pressure according to a plurality of the pressure adjustment coefficients.

5. The planetary wheel single station swage forming method of claim 4 wherein, The process of adjusting the downward speed of the punch according to the expansion rate under the condition that the radial deformation of the upsetting blank is determined to be non-uniform comprises: the expansion rate is compared with a preset rate; it is determined to decrease the downward speed based on the comparison result that the expansion rate is greater than the preset rate; wherein a plurality of speed adjustment coefficients are set based on a second rate difference value between the preset rate and the expansion rate, so as to decrease the downward speed according to a plurality of the speed adjustment coefficients.

6. The planetary wheel single station swage forming method of claim 1 wherein, The determination process of the axial deformation characteristic value comprises: the initial surface position of the upper surface of the upsetting blank and the real-time surface position at different stages in the stamping process are determined; the initial surface position and the real-time surface position are aligned with the geometric center as the reference to determine a plurality of vertical distances; the standard deviation of the plurality of vertical distances is determined as the axial deformation characteristic value. The first axial deformation representation value is an axial deformation representation value of an initial surface position and a real-time surface position at an early stage, and the second axial deformation representation value is an axial deformation representation value of the initial surface position and a real-time surface position at a middle stage.

7. The planetary wheel single station swage forming method of claim 6 wherein, The process of determining whether the axial deformation of the upsetting blank is uniform based on the second axial deformation representation value comprises: comparing the second axial deformation representation value with a preset axial deformation representation value; determining that the axial deformation of the upsetting blank is not uniform based on a comparison result that the second axial deformation representation value is greater than the preset axial deformation representation value.

8. The planetary wheel single station swage forming method of claim 7 wherein, The process of adjusting the holding time length of the final stage based on the axial deformation difference value comprises: comparing the axial deformation difference value with a preset deformation difference value; setting a plurality of time length adjustment coefficients based on a comparison result of the axial deformation difference value and the preset deformation difference value, and increasing the holding time length based on the plurality of time length adjustment coefficients.

9. The planetary wheel single station swage forming method of claim 8 wherein, The process of determining whether to optimize the pressure adjustment coefficient or the speed adjustment coefficient based on the batch fluctuation value comprises: comparing the batch fluctuation value with a preset fluctuation value; determining whether to optimize the pressure adjustment coefficient or the speed adjustment coefficient based on a comparison result that the batch fluctuation value is greater than the preset fluctuation value; wherein a plurality of pressure correction coefficients or a plurality of speed correction coefficients are set based on a fluctuation difference value of the batch fluctuation value and the preset fluctuation value, so that the pressure correction coefficients optimize the pressure adjustment coefficient, or the speed correction coefficients optimize the speed adjustment coefficient.

10. A planetary gear single station swage forming apparatus using the planetary gear single station swage forming method according to any one of claims 1 to 9, characterized by, comprise: a mechanical arm; a punching mechanism comprising a punch head sleeve movably connected with the mechanical arm, a punch head movably connected with the punch head sleeve, a die disposed below the punch head and aligned with the center of the punch head to place the upsetting blank, a die cushion block disposed in the die, and a die fixing plate movably connected with the die and the die cushion block at the bottom of the die; a data acquisition module comprising an image collector disposed on the side of the mechanical arm facing the die; a stamping control module connected with the data acquisition module, comprise, a radial deformation determination unit configured to determine radial deformation representation values of a plurality of positioning points, an expansion rate of an outer edge of the upsetting blank, and a first axial deformation representation value of the upsetting blank based on image information of the early stage, to determine whether the radial deformation of the upsetting blank is uniform based on the radial deformation representation values, and to determine whether to adjust the total pressure of the punch head by a pressure adjustment coefficient or the downward speed of the punch head by a speed adjustment coefficient according to the expansion rate under the condition that the radial deformation of the upsetting blank is determined to be non-uniform; an axial deformation determination unit configured to determine a second axial deformation representation value of the upsetting blank based on image information of the middle stage, to determine whether the axial deformation of the upsetting blank is uniform based on the second axial deformation representation value, and to adjust the holding time length of the final stage to obtain the punched blank based on an axial deformation difference value of the first axial deformation representation value and the second axial deformation representation value under the condition that the axial deformation is determined to be non-uniform. a correction unit to optimize the pressure adjustment coefficient or the speed adjustment coefficient based on batch fluctuation values of defect characterization parameters of the fracture zone on the punched section of the punched blank for several production batches.

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