Planet wheel single-station forging forming method and device

Abstract

The invention relates to the technical field of planet wheel single-station forging, in particular to a planet wheel single-station forging forming method and device.The method comprises the steps that whether radial deformation of an upset blank is uniform or not is determined based on a radial deformation characterization value, and under the condition that it is determined that the radial deformation of the upset blank is not uniform, the upset blank is subjected to single-station forging forming; determining the total pressure of the adjusting punch or the descending speed of the adjusting punch based on the expansion rate; whether the axial deformation of the upset blank is uniform or not is determined based on the second axial deformation characterization value, and under the condition that it is determined that the axial deformation is not uniform, the pressure maintaining duration of the last stage is adjusted based on the axial deformation difference value, and a punched blank is obtained; optimizing a pressure regulation coefficient or a speed regulation coefficient according to the batch fluctuation value of the defect characterization parameter; the device comprises a mechanical arm, a punching mechanism, a data acquisition module and a punching control module. The machining quality of the single station of the planet gear is improved.

Description

Technical Field

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

[0002] In the field of wind turbine manufacturing, planetary gears in megawatt-class wind turbine gearboxes are critical transmission components, and their performance directly impacts the stability and power generation efficiency of wind turbines. Currently, single-station forging is a key process for planetary gear manufacturing, but this process faces numerous challenges in terms of forming quality. Firstly, in traditional forging processes, the metal flow of the blank within a single station is difficult to precisely control. This leads to inadequate filling of the planetary gear tooth profile, resulting in insufficient tooth addendum fillet and irregular root fillet, severely impacting the gear meshing accuracy and load-bearing capacity. Secondly, during the single-station forging process, the uneven distribution of temperature and stress fields can easily lead to internal defects in the planetary gear, such as microcracks and looseness, significantly reducing the fatigue life of the planetary gear. Furthermore, limitations in die design and manufacturing precision result in poor fit between the blank and the die during forging, further exacerbating the deterioration of forming quality and resulting in high scrap rates. Improving the single-station forming quality of planetary gears and optimizing existing forging processes and equipment have become key issues that need to be addressed urgently.

[0003] Chinese patent application publication number: CN114700702A discloses a high-speed hot upsetting planetary half-shaft gear forming process. The specific steps of this process include: blanking, induction heating, shearing, blank shaping, station upsetting and final forming. It solves the defects that may be caused by burrs, collapsed angles, cutting marks, non-parallelism of the two end faces, external circle deformation and other adverse effects on tooth surface forming when hot forging bevel gears of Harbin Machinery.

[0004] The following problems also exist in the prior art: in the single-station processing process of punching the upsetting blank to form the punched blank in the prior art, there is a lack of monitoring and regulation of the radial deformation and lateral deformation of the upsetting blank, resulting in poor internal structural integrity of the punched blank, thereby resulting in poor single-station processing quality of the planetary gear. Summary of the Invention

[0005] To this end, the present invention provides a single-station forging method and device for a planetary gear, which is used to overcome the problem in the prior art of lack of monitoring and regulation of the radial deformation and lateral deformation of the upsetting blank, resulting in poor internal structural integrity of the punched blank, and thus leading to poor single-station processing quality of the planetary gear.

[0006] To achieve the above objectives, the present invention provides a single-station forging method for a planetary gear, comprising: Setting a plurality of positioning points on the upper surface of the upset blank to obtain a plurality of image information of the upper surface during the punching process, wherein the punching process includes an early stage, a middle stage, and a final stage; Determining radial deformation characterization values ​​of a plurality of positioning points, an expansion rate of an outer edge of the upsetting blank, and a first axial deformation characterization value of the upsetting blank based on image information from an early stage, determining whether the radial deformation of the upsetting blank is uniform based on the radial deformation characterization values, and, if it is determined that the radial deformation of the upsetting blank is non-uniform, adjusting the total pressure of the punch using a pressure adjustment coefficient according to the expansion rate, or adjusting the downward speed of the punch using a speed adjustment coefficient; Determining a second axial deformation characterization value of the upsetting blank based on image information at the mid-stage, determining whether the axial deformation of the upsetting blank is uniform based on the second axial deformation characterization value, and, if the axial deformation is determined to be non-uniform, adjusting a holding time at the final stage based on an axial deformation difference between the first axial deformation characterization value and the second axial deformation characterization value to obtain a punched blank; Defect characterization parameters of fracture zones on punching cross sections of the punching blanks of several production batches are obtained to optimize the pressure adjustment coefficient or the speed adjustment coefficient according to batch fluctuation values ​​of the defect characterization parameters.

[0007] Furthermore, the process of determining the radial deformation characterization value includes: Determining a plurality of displacement distances of the plurality of positioning points along a radial direction according to the image information; The standard deviation of the displacement distances is determined as a radial deformation characterization value.

[0008] Furthermore, the process of determining whether the radial deformation of the upsetting blank is uniform based on the radial deformation characterization value includes: comparing the radial deformation characterization value with a preset radial deformation characterization value; Based on the comparison result that the radial deformation characterization value is greater than the preset radial deformation characterization value, it is determined that the radial deformation of the upset blank is non-uniform.

[0009] Furthermore, 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: comparing the expansion rate with a preset rate; determining to increase the total pressure based on a 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 between the preset rate and the expansion rate, so as to increase the total pressure according to the plurality of pressure adjustment coefficients.

[0010] Furthermore, under the condition that the radial deformation of the upsetting blank is determined to be non-uniform, the process of adjusting the downward speed of the punch according to the expansion rate includes: comparing the expansion rate with a preset rate; Determining to reduce the downlink speed based on a 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 between the expansion rate and the preset rate, so as to reduce the downlink speed according to the plurality of speed adjustment coefficients.

[0011] Furthermore, the process of determining the axial deformation characterization value includes: Determine the initial surface position of the top surface of the upset blank and the real-time surface position at different stages of the stamping process; aligning the initial surface position and the real-time surface position based on a geometric center, and determining a plurality of vertical distances; Determine the standard deviation of the plurality of vertical spacings as a representative value of the axial deformation; The first axial deformation characterization value is an axial deformation characterization value of an initial surface position and a real-time surface position in an early stage, and the second axial deformation characterization value is an axial deformation characterization value of an initial surface position and a real-time surface position in a mid-stage.

[0012] Furthermore, the process of determining whether the axial deformation of the upsetting blank is uniform based on the second axial deformation characterization value includes: comparing the second axial deformation characterization value with a preset axial deformation characterization value; Based on the comparison result that the second axial deformation characterization value is greater than the preset axial deformation characterization value, it is determined that the axial deformation of the upset blank is non-uniform.

[0013] Furthermore, the process of adjusting the holding time in the final stage according to the axial deformation difference includes: comparing the axial deformation difference value with a preset deformation difference value; A plurality of time adjustment coefficients are set based on a comparison result between the axial deformation difference value and the preset deformation difference value, so as to increase the holding time based on the plurality of time adjustment coefficients.

[0014] Furthermore, the process of determining and optimizing the pressure adjustment coefficient or the speed adjustment coefficient based on the batch fluctuation value includes: comparing the batch fluctuation value with a preset fluctuation value; Determining 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; Among them, a number of pressure correction coefficients or a number of speed correction coefficients are set based on the fluctuation difference between the batch fluctuation value and the preset fluctuation value, and the pressure adjustment coefficient is optimized by the pressure correction coefficient, or the speed adjustment coefficient is optimized by the speed correction coefficient.

[0015] On the other hand, the present invention also provides a planetary gear single-station forging device, comprising: robotic arm; a punching mechanism comprising a punch sleeve movably connected to the robotic arm, a punch movably connected to the punch sleeve, a die disposed below the punch and aligned with the center of the punch for placing an upset blank, a die pad disposed within the die, and a die fixing plate disposed at the bottom of the die and movably connected to the die and the die pad; A data acquisition module, comprising an image collector provided on a side of the robotic arm facing the mold; A stamping control module, connected to the data acquisition module, includes: a radial deformation determination unit configured to determine, based on image information from an early stage, radial deformation characterization values ​​of a plurality of the positioning points, an expansion rate of an outer edge of the upsetting blank, and a first axial deformation characterization value of the upsetting blank, so as to determine whether the radial deformation of the upsetting blank is uniform based on the radial deformation characterization values, and, if it is determined that the radial deformation of the upsetting blank is non-uniform, to determine, based on the expansion rate, whether to adjust the total pressure of the punch using a pressure adjustment coefficient or to adjust the downward speed of the punch using a speed adjustment coefficient; an axial deformation determination unit, configured to determine a second axial deformation characterization value of the upsetting blank based on the image information of the intermediate stage, determine whether the axial deformation of the upsetting blank is uniform based on the second axial deformation characterization value, and, if the axial deformation is determined to be uneven, adjust a holding time in a final stage based on an axial deformation difference between the first axial deformation characterization value and the second axial deformation characterization value to obtain a punched blank; A correction unit is used to optimize the pressure adjustment coefficient or the speed adjustment coefficient based on batch fluctuation values ​​of defect characterization parameters of fracture zones on punching cross sections of the punching blanks of several production batches.

[0016] Compared with the prior art, the beneficial effect of the present invention lies in that, by setting a number of positioning points on the surface of the upsetting blank, the radial deformation characterization value is determined according to the displacement distance of each positioning point during the punching process of the upsetting blank to determine whether the radial deformation of the upsetting blank in the early stage is uniform, and the total pressure of the punch or the downward speed of the punch is adjusted under the condition that the radial deformation in the early stage is determined to be uneven, so as to correct the radial deformation uniformity of the upsetting blank in the remaining stamping process; the image information of the mid-term stage is obtained to determine the second axial deformation characterization value, and whether the axial deformation of the upsetting blank in the stamping process is uniform according to the axial deformation characterization value, and the holding time in the final stage is increased under the condition that the axial deformation is determined to be uneven, 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 to further improve the radial deformation uniformity and axial deformation uniformity of the upsetting blank in the punching process, thereby improving the internal integrity of the punching blank and improving the processing quality of the planetary gear single station.

[0017] Furthermore, the present invention determines the total pressure of the punch or the downward speed of the punch according to the expansion rate under the condition of determining the uneven radial deformation. Under the condition of a large expansion rate, the unevenness of the radial deformation will be further aggravated, and the downward speed of the punch needs to be appropriately reduced. Under the condition of a small expansion rate, the total pressure of the punch needs to be appropriately increased. The expansion rate is essentially the flow speed of the metal along the radial direction, and its size directly reflects the activity of the plastic deformation of the material. If the expansion rate is too large, the area with small flow resistance will expand outward rapidly due to inertia, while the area with large flow resistance will lag behind, resulting in significant differences in the deformation amount at different radial positions. 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 per unit time, which will further widen the flow speed difference in different areas. Therefore, reducing the downward speed of the punch can reduce the impact of metal flow. The expansion rate is low, and the root cause of the uneven radial deformation is insufficient flow driving force. The low expansion rate means insufficient power for the plastic flow of the metal. At this time, it is difficult for the material to expand uniformly 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 on the upsetting blank, the stronger the plastic deformation ability of the material, and the more sufficient the metal's radial penetration flow. Therefore, increasing the total pressure of the punch can strengthen the extrusion effect on the upsetting blank, push the metal to replenish the slow-flowing area, eliminate the thickness deviation caused by insufficient power, and correct the uniformity of the radial deformation, thereby further improving the internal integrity of the punching blank and improving the processing quality of the planetary gear single station.

[0018] Furthermore, under the condition of determining that the axial deformation of the upsetting blank is uneven, the present invention appropriately extends the holding time in the final stage, drives the metal's shrinkage flow through continuous pressure to compensate for the axial deformation deviation in the main deformation stage, thereby correcting the axial deformation uniformity, thereby further improving the internal integrity of the punching blank and improving the processing quality of the planetary gear single station. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a flow chart of a single-station forging method for a planetary gear according to an embodiment of the present invention; Figure 2 A flow chart for determining whether radial deformation of an upsetting blank is uniform according to an embodiment of the present invention; Figure 3 A flow chart for determining whether the axial deformation of an upsetting blank is uniform according to an embodiment of the present invention; Figure 4 This is a schematic structural diagram of a single-station forging device for a planetary gear according to an embodiment of the present invention; In the figure: 1. punch sleeve, 2. punch, 3. die, 4. die pad, 5. die fixing plate, 6. upsetting blank, 7. image collector, 8. robotic arm. DETAILED DESCRIPTION

[0020] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0022] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside", and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is only 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. Therefore, it cannot be understood as a limitation on the present invention.

[0023] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0024] See also Figure 1-Figure 3 As shown, Figure 1 This is a flow chart of a single-station forging method for a planetary gear according to an embodiment of the present invention; Figure 2 A flow chart for determining whether radial deformation of an upsetting blank is uniform according to an embodiment of the present invention; Figure 3 The flowchart of an embodiment of the present invention is used to determine whether the axial deformation of an upset blank is uniform.

[0025] The single-station forging method for a planetary gear according to an embodiment of the present invention includes: Step S1, setting a plurality of positioning points on the upper surface of the upset blank, and obtaining a plurality of image information of the upper surface during the punching process, wherein the punching process includes an early stage, a middle stage, and a final stage; Step S2: determining radial deformation characterization values ​​of a plurality of positioning points, an expansion rate of an outer edge of the upsetting blank, and a first axial deformation characterization value of the upsetting blank based on image information from an early stage, determining whether the radial deformation of the upsetting blank is uniform based on the radial deformation characterization values, and, if it is determined that the radial deformation of the upsetting blank is non-uniform, determining whether to adjust the total pressure of the punch using a pressure adjustment coefficient or to adjust the downward speed of the punch using a speed adjustment coefficient based on the expansion rate; Step S3: determining a second axial deformation characterization value of the upsetting blank based on the image information of the mid-stage, determining whether the axial deformation of the upsetting blank is uniform based on the second axial deformation characterization value, and, if the axial deformation is determined to be uneven, adjusting the holding time of the final stage based on the axial deformation difference between the first axial deformation characterization value and the second axial deformation characterization value to obtain a punched blank; Step S4, obtaining defect characterization parameters of fracture zones on punching cross sections of the punching blanks of several production batches, so as to optimize the pressure adjustment coefficient or the speed adjustment coefficient according to batch fluctuation values ​​of the defect characterization parameters.

[0026] Specifically, the manufacturing process of the planetary gear includes cutting, heating, upsetting, upsetting, one-time punching and die forging, and machining to remove excess parts. The embodiment of the present invention is only for the one-time punching and die forging process of the upsetting blank. The blank after upsetting is a solid round 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. During the punching process, the punch applies axial pressure to the center of the upsetting blank, forcing the central metal to flow radially, and finally forming a through hole matching the size of the punch. The radially flowing metal during punching increases the outer diameter of the blank. At the same time, the axial height is reduced due to the extrusion and extension of the metal.

[0027] Specifically, the method of setting positioning points on the upper surface of the upsetting blank is: high-temperature resistant materials such as tungsten, molybdenum, alumina and zirconia are adhered to the upper surface of the upsetting blank by physical spot welding, plasma spraying or laser cladding to form positioning points. The positions of the positioning points can be set uniformly at preset angles along a circle with the geometric center of the upsetting blank as the center and a preset distance (greater than the punch diameter) as the diameter. Taking an upsetting blank with a diameter of 300 mm as an example, the punch diameter is 50 mm, and 6 positioning points can be set at an angle interval of 60° along a circle with a diameter of 100 mm.

[0028] Specifically, the device used in the embodiment of the present invention to obtain image information of the upper surface of the upset blank during the punching process is an image collector, such as a near-infrared enhanced industrial camera of model SAP-2501NIR-GE, and the specific model is not limited.

[0029] Specifically, the punching process can be divided into several stages according to the thickness of the blank. For example, the early stage is from the time when the punch contacts the upset blank to the time when the punching depth reaches 1 / 3 of the thickness of the upset blank. The middle stage is from the time when the punching depth reaches 1 / 3 to 2 / 3 of the thickness of the upset blank. The final stage is from the time when the punching depth reaches 2 / 3 of the thickness of the upset blank to the completion of the punching. There is no specific limitation.

[0030] Specifically, the process of determining the radial deformation characterization value includes: Determining a plurality of displacement distances of the plurality of positioning points along a radial direction according to the image information; The standard deviation of the displacement distances is determined as a radial deformation characterization value.

[0031] Specifically, after several images acquired by the industrial camera are pre-processed by grayscale conversion and denoising, the positioning points on the blank surface in adjacent frame images are compared to calculate the displacement distance of each point.

[0032] Specifically, the process of determining whether the radial deformation of the upsetting blank is uniform based on the radial deformation characterization value includes: comparing the radial deformation characterization value with a preset radial deformation characterization value; Determining that the radial deformation of the upsetting blank is non-uniform based on a comparison result that the radial deformation characterization value is greater than the preset radial deformation characterization value; The radial deformation of the upset blank is determined to be uniform based on a comparison result that the radial deformation characterization value is less than or equal to the preset radial deformation characterization value.

[0033] Specifically, the preset radial deformation value has a range of [2 mm, 5 mm], and 3 mm is preferred in the embodiment of the present invention.

[0034] It can be understood that under the condition of uniform radial deformation of the upsetting blank, the displacement distances of several positioning points should be close along the radial direction, the discrete degree of each displacement distance is low, and the corresponding standard deviation value is small. When the radial deformation of the upsetting blank is uneven, the discrete degree of each displacement distance is high and the standard deviation will be large.

[0035] Specifically, 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: comparing the expansion rate with a preset rate; determining to increase the total pressure based on a 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 between the preset rate and the expansion rate, so as to increase the total pressure according to the plurality of pressure adjustment coefficients.

[0036] Specifically, comparing the first rate difference with a preset difference; determining to increase the total pressure by a first pressure adjustment coefficient based on a comparison result that the first rate difference is greater than the preset difference; The total pressure is increased by a second pressure adjustment coefficient based on a comparison result that the first rate difference is less than or equal to the preset difference.

[0037] Specifically, the expansion rate is the average displacement increment of the outer edge of the upsetting blank in the radial direction per unit time.

[0038] Specifically, the value range of the preset rate is set to [5mm / s, 20mm / s], and the embodiment of the present invention is preferably 10mm / s; the value range of the preset difference is set to [2mm / s, 4mm / s], and the embodiment of the present invention is preferably 3mm / s; the value range of the first pressure adjustment coefficient is set to [1.05, 1.08], and the embodiment of the present invention is preferably 1.06; the value range of the second pressure adjustment coefficient is set to [1.01, 1.04], and the embodiment of the present invention is preferably 1.03.

[0039] Specifically, under the condition that the radial deformation of the upsetting blank is determined to be non-uniform, the process of adjusting the downward speed of the punch according to the expansion rate includes: comparing the expansion rate with a preset rate; Determining to reduce the downlink speed based on a 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 between the expansion rate and the preset rate, so as to reduce the downlink speed according to the plurality of speed adjustment coefficients.

[0040] Specifically, comparing the second rate difference with a preset difference; Determining to reduce the downlink speed by a first speed adjustment coefficient based on a comparison result that the second rate difference is greater than the preset difference; Based on a comparison result that the second rate difference is less than or equal to the preset difference, it is determined to reduce the downlink speed by a second speed adjustment coefficient.

[0041] Specifically, the value range of the first speed adjustment coefficient is set to [0.92, 0.95], and the preferred value in the embodiment of the present invention is 0.93; the value range of the second speed adjustment coefficient is set to [0.96, 0.99], and the preferred value in the embodiment of the present invention is 0.97.

[0042] It is understandable that excessive expansion rate of the outer edge of the upsetting blank will lead to amplified local differences. Therefore, the downward speed of the punch is appropriately reduced, the deformation time of the metal is prolonged, and the local resistance control of the die pad has more time to guide the metal to flow evenly, 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 relatively small, the total pressure of the punch is appropriately increased to enhance the overall driving force, and the low resistance design of the die pad in the lag area is combined to promote the flow of metal to this area. At the same time, the high resistance design of the die pad in the area where the flow is too fast can offset the additional driving force brought about by the increase in total pressure, thereby correcting the deformation uniformity of the upsetting blank during the stamping process.

[0043] Specifically, the die pad is an internal component of the mold that is in direct contact with the blank. Its local physical properties such as thickness and hardness will significantly affect the deformation resistance of different areas of the upsetting blank, thereby guiding the direction of metal flow.

[0044] Specifically, the process of determining the axial deformation characterization value includes: Determine the initial surface position of the top surface of the upset blank and the real-time surface position at different stages of the stamping process; aligning the initial surface position and the real-time surface position based on a geometric center, and determining a plurality of vertical distances; The standard deviation of a number of the vertical spacings is determined as a representative value of the axial deformation.

[0045] Specifically, the first axial deformation characterization value is the axial deformation characterization value of the initial surface position and the real-time surface position in the early stage, and the second axial deformation characterization value is the axial deformation characterization value of the initial surface position and the real-time surface position in the middle stage.

[0046] Specifically, the process of determining whether the axial deformation of the upsetting blank is uniform based on the second axial deformation characterization value includes: comparing the second axial deformation characterization value with a preset axial deformation characterization value; Determining that the axial deformation of the upsetting blank is non-uniform based on a comparison result that the second axial deformation characterization value is greater than the preset axial deformation characterization value; Based on the comparison result that the second axial deformation characterization value is less than or equal to the preset axial deformation characterization value, it is determined that the axial deformation of the upset blank is uniform.

[0047] Specifically, the preset axial deformation characterization value has a value range of [0.4 mm, 0.8 mm], and is preferably 0.6 mm in the embodiment of the present invention.

[0048] Specifically, in the stamping process of the upsetting blank, radial flow is the main deformation direction in the early stage, and the metal tends to flow to the radial area with small resistance. If the edge of the blank is not in close contact with the die, the radial flow resistance is small, the edge metal flows more in the radial direction, and the center is directly compressed by the punch, the axial compression is more significant, and the thinning rate of the outer edge will be lower than that of the central area, forming a situation where the center is thin and the edge is thick, 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 has changed from local contact to full fit, and the axial The axial pressure is more evenly transmitted to the entire surface of the upsetting blank through the die interface, the local concentration of pressure distribution is weakened, and the driving force for thickness thinning is more balanced. At the same time, the radial constraint of the metal by the inner wall of the die and the die pad is enhanced, and it is more difficult for the metal to escape axial compression through preferential radial flow, and is forced to thin more evenly in the axial direction. The die pad can adjust its support force to exert additional resistance on the local thicker area, forcing the metal in this area to be more fully compressed axially, further improving the thickness uniformity of the upsetting blank. The smaller the axial deformation characterization value, the more uniform the thickness of the upsetting blank and the more uniform the axial deformation.

[0049] Specifically, the process of adjusting the holding time in the final stage according to the axial deformation difference includes: comparing the axial deformation difference value with a preset deformation difference value; A plurality of time adjustment coefficients are set based on a comparison result between the axial deformation difference value and the preset deformation difference value, so as to increase the holding time based on the plurality of time adjustment coefficients.

[0050] Specifically, based on the comparison result that the axial deformation difference value is greater than the preset deformation difference value, it is determined that the holding time is increased by a first time adjustment coefficient; Based on the comparison result that the axial deformation difference value is less than or equal to the preset deformation difference value, it is determined to increase the holding time by a second time adjustment coefficient.

[0051] Specifically, the value range of the preset deformation difference is set to [0.05mm, 0.2mm], and the embodiment of the present invention preferably is 0.1mm; the value range of the second duration adjustment coefficient is set to [1.2, 1.4], and the embodiment of the present invention preferably is 1.25; the value range of the first duration adjustment coefficient is set to [1.41, 1.6], and the embodiment of the present invention preferably is 1.45.

[0052] It can be understood that the larger the axial deformation difference value is, the better the thickness uniformity of the upsetting blank is in the mid-stage, and the shorter the holding time that needs to be increased is.

[0053] Specifically, under the condition that the axial deformation of the upsetting blank is determined to be uneven, the holding time in the final stage can be appropriately increased to increase the uniformity of the axial deformation. For the upsetting blank of high-strength and large-sized planetary gears, the plastic deformation of the metal depends not only on the external force, but also on the deformation time. The plastic deformation mechanisms such as atomic diffusion and grain boundary sliding in the metal require a certain amount of time to be fully activated. The core of the final holding stage is: under the premise of stable punch position, by continuously maintaining pressure, a supplementary flow window time is provided for the area that is not fully deformed in the mid-term. At the same time, there is a tendency for elastic rebound after plastic deformation of the metal, especially in the high-stress area. The area with uneven thickness in the mid-term is often accompanied by higher residual stress. If the stamping is terminated directly, the rebound may aggravate the thickness deviation. Therefore, extending the holding time in the final stage can allow the blank to fully and slowly release the residual stress under continuous pressure, reduce the amount of elastic recovery, and allow the metal to complete the final forming under a more stable stress state, ensuring that the thickness uniformity is not easily deteriorated by rebound in subsequent processes.

[0054] Specifically, the defect characterization parameter refers to the percentage of defect area present on the punching section per unit area, wherein defects include but are not limited to dislocations, microcracks and tear edges, which are determined based on the image information of the punching section. This is a prior art and will not be elaborated on. The batch fluctuation value of the defect characterization parameter is the standard deviation of the defect characterization parameter of each batch.

[0055] Specifically, the process of determining and optimizing the pressure adjustment coefficient or the speed adjustment coefficient based on the batch fluctuation value includes: comparing the batch fluctuation value with a preset fluctuation value; Determining 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; Determining not to optimize the pressure adjustment coefficient or the speed adjustment coefficient based on a comparison result that the batch fluctuation value is less than or equal to the preset fluctuation value; Among them, a number of pressure correction coefficients or a number of speed correction coefficients are set based on the fluctuation difference between the batch fluctuation value and the preset fluctuation value, and the pressure adjustment coefficient is optimized by the pressure correction coefficient, or the speed adjustment coefficient is optimized by the speed correction coefficient.

[0056] Specifically, the fluctuation difference is compared with a preset fluctuation difference; Based on the comparison result that the fluctuation difference is greater than the preset fluctuation difference, determining to reduce the pressure adjustment coefficient by the first pressure correction coefficient, or to reduce the speed adjustment coefficient by the first speed correction coefficient; 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.

[0057] Specifically, the value range of the preset fluctuation value is set to [0.05%, 0.15%], and the embodiment of the present invention is preferably 0.1%; the value range of the preset fluctuation difference is set to [0.02%, 0.04%], and the embodiment of the present invention is preferably 0.03%; the value range of the first pressure correction coefficient is set to [0.88, 0.93], and the embodiment of the present invention is preferably 0.9; the value range of the first speed correction coefficient is set to [0.85, 0.9], and the embodiment of the present invention is preferably 0.87; the value range of the second pressure correction coefficient is set to [0.94, 0.97], and the embodiment of the present invention is preferably 0.955; the value range of the second speed correction coefficient is set to [0.91, 0.95], and the embodiment of the present invention is preferably 0.925.

[0058] Specifically, during the punching process, the generation of defects is directly related to pressure and speed. Pressure determines the uniformity of plastic deformation of the material. Excessive pressure may cause stress concentration and form microcracks. Speed ​​affects the deformation rate and energy accumulation. Too high a speed will cause material flow lag, resulting in a surge in local strain rate and brittle fracture defects. The formation of the fracture zone is accompanied by severe plastic deformation and tearing. There are a large number of dislocations, microcracks and grain boundary damage in the microstructure. For high-strength alloy steels, these defects may further develop into delamination or falling blocks, 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.

[0059] See also Figure 4 As shown in FIG, it is a schematic structural diagram of a single-station forging device for a planetary gear according to an embodiment of the present invention.

[0060] The single-station forging device for planetary gears according to the embodiment of the present invention comprises: Robotic arm 8; The punching mechanism includes a punch sleeve 1 movably connected to the robotic arm 8, a punch 2 movably connected to the punch sleeve 1, a die 3 arranged below the punch 2 and aligned with the center of the punch 2 for placing an upset blank 6, a die pad 4 arranged in the die 3, and a die fixing plate 5 arranged at the bottom of the die 3 and movably connected to the die 3 and the die pad 4; A data acquisition module, comprising an image collector 7 provided on a side of the robotic arm 8 facing the mold 3; A stamping control module, connected to the data acquisition module, includes: a radial deformation determination unit, configured to determine, based on image information from an early stage, radial deformation characterization values ​​of a plurality of the positioning points, an expansion rate of the outer edge of the upsetting blank 6, and a first axial deformation characterization value of the upsetting blank 6, so as to determine whether the radial deformation of the upsetting blank 6 is uniform based on the radial deformation characterization values, and, if it is determined that the radial deformation of the upsetting blank 6 is non-uniform, determine, based on the expansion rate, whether to adjust the total pressure of the punch 2 using a pressure adjustment coefficient, or to adjust the downward speed of the punch 2 using a speed adjustment coefficient; an axial deformation determination unit, configured to determine a second axial deformation characterization value of the upsetting blank 6 based on the image information of the intermediate stage, determine whether the axial deformation of the upsetting blank 6 is uniform based on the second axial deformation characterization value, and, if the axial deformation is determined to be uneven, adjust the holding time of the final stage based on the axial deformation difference between the first axial deformation characterization value and the second axial deformation characterization value to obtain a punched blank; A correction unit is used to optimize the pressure adjustment coefficient or the speed adjustment coefficient based on batch fluctuation values ​​of defect characterization parameters of fracture zones on punching cross sections of the punching blanks of several production batches.

[0061] 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 robotic arm 8, the punch 2 is inserted from the bottom of the punch sleeve 1, and is fixed to the punch sleeve 1 and the robotic arm 8 with a pin. The die fixing plate 5 is placed on the press turntable and fixed in the middle of the turntable by mechanical cooperation. The die pad 4 is placed in the die, and the die is placed on the die fixing plate 5 in the same way. The punch 2 is pressed down under the control of the stamping control module until it is shown in the figure, and when it is pulled out, the punching process of the upsetting blank 6 is completed.

[0062] Specifically, the punch angle of the punch 2 is 0.4°, which refers to the inclination angle of the forming surface where the punch 2 contacts the upsetting blank 6 relative to the axis of the upsetting blank 6. The die pad 4 is 40 mm deep and is grooved using a concave pit.

[0063] Specifically, the punch sleeve 1 and the punch 2 are connected by a pin to prevent the workpiece from sticking to the punch 2 and the workpiece from being unable to be taken out of the robot arm 8. After the pin is pulled out, the punch 2 is separated from the punch sleeve 1 and the robot arm 8, and the workpiece can then be separated from the punch 2; through the innovation of the mold 3, "extrusion instead of punching, forging instead of rolling" is achieved, the process is integrated, the ring rolling process and the secondary punching process are eliminated, and the grain streamlines of the finally formed planetary gear are directionally distributed along the tooth profile, the tooth root tensile strength is increased to more than 1100MPa, and the yield strength is increased to more than 930MPa.

[0064] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A single-station forging method for a planetary gear, characterized in that: include: Setting a plurality of positioning points on the upper surface of the upset blank to obtain a plurality of image information of the upper surface during the punching process, wherein the punching process includes an early stage, a middle stage, and a final stage; Determining radial deformation characterization values ​​of a plurality of positioning points, an expansion rate of an outer edge of the upsetting blank, and a first axial deformation characterization value of the upsetting blank based on image information from an early stage, determining whether the radial deformation of the upsetting blank is uniform based on the radial deformation characterization values, and, if it is determined that the radial deformation of the upsetting blank is non-uniform, determining whether to adjust the total pressure of the punch using a pressure adjustment coefficient or to adjust the downward speed of the punch using a speed adjustment coefficient based on the expansion rate; Determining a second axial deformation characterization value of the upsetting blank based on image information at the mid-stage, determining whether the axial deformation of the upsetting blank is uniform based on the second axial deformation characterization value, and, if the axial deformation is determined to be non-uniform, adjusting a holding time at the final stage based on an axial deformation difference between the first axial deformation characterization value and the second axial deformation characterization value to obtain a punched blank; Defect characterization parameters of fracture zones on punching cross sections of the punching blanks of several production batches are obtained to optimize the pressure adjustment coefficient or the speed adjustment coefficient according to batch fluctuation values ​​of the defect characterization parameters.

2. The planetary gear single-station forging method according to claim 1, characterized in that: The process of determining the radial deformation characterization value includes: Determining a plurality of displacement distances of the plurality of positioning points along a radial direction according to the image information; The standard deviation of the displacement distances is determined as a radial deformation characterization value.

3. The planetary gear single-station forging method according to claim 2, characterized in that: The process of determining whether the radial deformation of the upsetting blank is uniform based on the radial deformation characterization value includes: comparing the radial deformation characterization value with a preset radial deformation characterization value; Based on the comparison result that the radial deformation characterization value is greater than the preset radial deformation characterization value, it is determined that the radial deformation of the upset blank is non-uniform.

4. The single-station forging method for planetary gears according to claim 3, characterized in that: 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: comparing the expansion rate with a preset rate; determining to increase the total pressure based on a 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 between the preset rate and the expansion rate, so as to increase the total pressure according to the plurality of pressure adjustment coefficients.

5. The planetary gear single-station forging method according to claim 4, characterized in that: Under the condition that the radial deformation of the upsetting blank is determined to be non-uniform, the process of adjusting the downward speed of the punch according to the expansion rate includes: comparing the expansion rate with a preset rate; Determining to reduce the downlink speed based on a 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 between the expansion rate and the preset rate, so as to reduce the downlink speed according to the plurality of speed adjustment coefficients.

6. The planetary gear single-station forging method according to claim 1, characterized in that: The process of determining the axial deformation characterization value includes: Determine the initial surface position of the top surface of the upset blank and the real-time surface position at different stages of the stamping process; aligning the initial surface position and the real-time surface position based on a geometric center, and determining a plurality of vertical distances; Determine the standard deviation of the plurality of vertical spacings as a representative value of the axial deformation; The first axial deformation characterization value is an axial deformation characterization value of an initial surface position and a real-time surface position in an early stage, and the second axial deformation characterization value is an axial deformation characterization value of an initial surface position and a real-time surface position in a mid-stage.

7. The single-station forging method for planetary gears according to claim 6, characterized in that: The process of determining whether the axial deformation of the upsetting blank is uniform based on the second axial deformation characterization value includes: comparing the second axial deformation characterization value with a preset axial deformation characterization value; Based on the comparison result that the second axial deformation characterization value is greater than the preset axial deformation characterization value, it is determined that the axial deformation of the upset blank is non-uniform.

8. The single-station forging method for planetary gears according to claim 7, characterized in that: The process of adjusting the holding time in the final stage according to the axial deformation difference includes: comparing the axial deformation difference value with a preset deformation difference value; A plurality of time adjustment coefficients are set based on a comparison result between the axial deformation difference value and the preset deformation difference value, so as to increase the holding time based on the plurality of time adjustment coefficients.

9. The single-station forging method for planetary gears according to claim 8, characterized in that: The process of determining and optimizing the pressure adjustment coefficient or the speed adjustment coefficient based on the batch fluctuation value includes: comparing the batch fluctuation value with a preset fluctuation value; Determining 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; Among them, a number of pressure correction coefficients or a number of speed correction coefficients are set based on the fluctuation difference between the batch fluctuation value and the preset fluctuation value, and the pressure adjustment coefficient is optimized by the pressure correction coefficient, or the speed adjustment coefficient is optimized by the speed correction coefficient.

10. A planetary gear single-station forging device using the planetary gear single-station forging method according to any one of claims 1 to 9, characterized in that: include: robotic arm; a punching mechanism comprising a punch sleeve movably connected to the robotic arm, a punch movably connected to the punch sleeve, a die disposed below the punch and aligned with the center of the punch for placing an upset blank, a die pad disposed within the die, and a die fixing plate disposed at the bottom of the die and movably connected to the die and the die pad; A data acquisition module, comprising an image collector provided on a side of the robotic arm facing the mold; A stamping control module connected to the data acquisition module, include, a radial deformation determination unit configured to determine, based on image information from an early stage, radial deformation characterization values ​​of a plurality of the positioning points, an expansion rate of an outer edge of the upsetting blank, and a first axial deformation characterization value of the upsetting blank, so as to determine whether the radial deformation of the upsetting blank is uniform based on the radial deformation characterization values, and, if it is determined that the radial deformation of the upsetting blank is non-uniform, to determine, based on the expansion rate, whether to adjust the total pressure of the punch using a pressure adjustment coefficient or to adjust the downward speed of the punch using a speed adjustment coefficient; an axial deformation determination unit, configured to determine a second axial deformation characterization value of the upsetting blank based on the image information of the intermediate stage, determine whether the axial deformation of the upsetting blank is uniform based on the second axial deformation characterization value, and, if the axial deformation is determined to be uneven, adjust a holding time in a final stage based on an axial deformation difference between the first axial deformation characterization value and the second axial deformation characterization value to obtain a punched blank; A correction unit is used to optimize the pressure adjustment coefficient or the speed adjustment coefficient based on batch fluctuation values ​​of defect characterization parameters of fracture zones on punching cross sections of the punching blanks of several production batches.

Images