Precise forming process and forging device for air chamber of automobile brake system

Abstract

The invention relates to the technical field of automobile part forming, and discloses an automobile brake system air chamber precise forming process which comprises the following steps: cutting an original blank by adopting split forging to obtain an upper shell blank and a lower shell blank; the upper shell blank and the lower shell are subjected to upsetting treatment, and an upper upsetting blank and a lower upsetting blank are obtained; the upper upsetting blank is put into an upper shell pre-forging die for pre-forging and then put into an upper shell finish-forging die for finish-forging, and an upper shell finish-forging blank is obtained; and the lower upsetting blank is put into a lower shell finish forging die to be subjected to finish forging, and a lower shell forged blank is obtained. Through the near-net forming forging process, the machining allowance is reduced to the maximum extent, the material utilization rate is increased to 70%, the tensile strength of a finished part is increased to 345 MPa, the ductility is increased to 12%, and good air tightness is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobile accessory forming, in particular to a precision forming process and forging device for an automobile brake system air chamber. BACKGROUND

[0002] In order to meet the requirements of high strength, high air tightness and compact space layout, the modern air chamber design tends to be complex in geometry with deep cavity, thin wall and multiple ribs. Such structural characteristics make the traditional manufacturing process face severe technical bottlenecks, especially in precision forming, material utilization and cost control. A mainstream process such as CNC machining and forging technology can meet the production requirements to a certain extent, but its inherent defects have seriously restricted the upgrading of the industry.

[0003] Specifically, in the CNC machining step, the excess amount is gradually removed from the aluminum alloy bar to form the air chamber structure through milling, turning and other processes, which can achieve high dimensional accuracy (±0.05mm), but the material utilization rate is low, and the machining allowance is generally 40%-60%. Taking a new energy automobile brake air chamber as an example, the single piece CNC machining time is more than 35 minutes, the tool wear cost accounts for as high as 18%, and the surface layer grain is broken due to the severe friction between the tool and the material during the cutting process, which significantly reduces the fatigue life of the part (the measured life is reduced by more than 30%), and the machining of deep cavity structure (cavity depth ratio ≥ 3:1) requires frequent tool replacement and clamping adjustment, further exacerbating the contradiction between efficiency and cost.

[0004] Although the forging process can reduce material waste through die forming, it has fundamental defects when applied to complex air chamber structures. During die casting, the metal melt is prone to entrain gas during high-speed filling, forming internal pores and leading to high unqualified air tightness test. A brake system supplier uses ADC12 aluminum alloy to die cast the air chamber, with a leakage rate of up to 8% at 0.8MPa pressure test, far exceeding the ≤0.5% requirement of ISO 26262 standard. In addition, the mechanical properties of the as-cast aluminum alloy are insufficient (tensile strength ≤240MPa), making it difficult to meet the high load requirements of heavy vehicle brake air chambers, forcing the wall thickness to increase by 20% to compensate for the strength defects, which in turn offsets the lightweight advantage.

[0005] Another defect of the forging process is the incomplete filling of thin-walled structures. When the wall thickness is ≤3mm, the temperature of the melt front drops sharply, causing loss of flowability, and the measured unfilled area accounts for 5%-8%, which needs to be repaired or scrapped, significantly increasing the cost.

[0006] Therefore, the traditional forging technology still has significant limitations in processing deep cavity and multi-joint structure. Firstly, the mold design complexity is high: the deep cavity structure requires the mold cavity to have very high surface finish and accurate draft angle, the porosity of the forging process is high, and the cost of CNC is too high, so the existing mold processing technology cannot balance the economy and precision; secondly, the material flow control is difficult: the filling of multi-joint structure needs to accurately coordinate the multi-directional compressive stress, and the traditional unidirectional forging is easy to produce folding defects, and the traditional forging cannot solve the problems of insufficient filling of the air chamber deep cavity, folding defects of the joint, and thin wall deformation. SUMMARY

[0007] The purpose of the present application is to provide an automobile brake system air chamber precision forming process and forging device to solve the technical problems in the prior art.

[0008] To solve the above technical problems, the present application specifically provides the following technical solutions: The present application provides an automobile brake system air chamber precision forming process, comprising the following steps: S100, using split forging, cutting the original blank to obtain an upper shell blank and a lower shell blank; S200, respectively performing first heat treatment on the upper shell blank and the lower shell blank, and performing upsetting treatment on the upper shell blank and the lower shell to obtain an upper upsetting blank and a lower upsetting blank, until the diameter of the upper shell blank is the same as the diameter of the upper die cavity, and the diameter of the lower shell blank is the same as the diameter of the lower die cavity; S300, using a first press to put the upper upsetting blank into an upper shell pre-forging die for pre-forging, and then into an upper shell finish-forging die for finish-forging, to obtain an upper shell finish-forging blank; S400, using a first press to put the lower upsetting blank into a lower shell finish-forging die for finish-forging, to obtain a lower shell finish-forging blank, and using a trimming die to trim the lower shell finish-forging blank, to obtain a lower shell forging blank; S500, performing second heat treatment on the upper shell finish-forging blank and the lower shell forging blank, to obtain an air chamber upper shell forging and an air chamber lower shell forging.

[0009] As a preferred embodiment of the present application, the original blank is aluminum alloy 6061-T6.

[0010] As a preferred embodiment of the present application, in the S200 step, the upsetting treatment comprises the following steps: S201. Heat the upper shell blank to 520±10℃, place it in the upper shell upsetting mold, and apply axial pressure to the upper shell blank through a hydraulic press to increase the blank diameter from 90mm to 200mm and compress the height from 110mm to 35mm, with a deformation of 68%. After upsetting, the surface of the blank is sprayed with graphite lubricant. S202. The lower shell blank is heated to 520±10℃ and placed in the upper shell upsetting mold. Axial pressure is applied to the upper shell blank by a hydraulic press, so that the blank diameter increases from 90mm to 120mm and the height is compressed from 85mm to 45mm, with a deformation of 47%. After upsetting, graphite lubricant is sprayed on the surface of the blank.

[0011] As a preferred embodiment of the present invention, the pre-forging and the final forging satisfy the following conditions: the press is a 2500t electric screw press with an impact energy of 150kJ and an impact speed of 0.8m / s.

[0012] As a preferred embodiment of the present invention, the edge trimming process includes the following steps: S401. Cool the lower shell final forging billet to below 150°C, and place the lower shell final forging billet in the edge trimming device; S402. The lower shell final forging billet is trimmed using a second press at a shearing speed of 10 mm / s, with a flash thickness of <0.5 mm and a blank edge burr of ≤0.05 mm. The second press is a 400t mechanical press.

[0013] In a preferred embodiment of the present invention, the temperature of the first heat treatment is 500-525°C, and the holding time is 1.5-2 hours; The second heat treatment includes the following steps: The upper shell final forging billet and the lower shell forging billet are solution treated at 530℃, held at the temperature for 3 hours, quenched with room temperature water, and held at 175℃ for 8 hours in an aging furnace to obtain the forging billet. The forging blank is subjected to water cooling, etching, pickling, and shot blasting processes to obtain a forging with work hardening and a smooth surface.

[0014] This invention provides a forging apparatus for the precision forming process of air chambers in automotive braking systems, including an integrated forging apparatus for pre-forging and final forging of irregularly shaped cavities and an edge trimming apparatus. The irregular cavity pre-forging and final forging integrated forging device is used to forge the upper upsetting billet; The trimming device includes an upper trimming base plate and a lower trimming base plate. The upper trimming base plate is fixed to the slider of the press, and the lower trimming base plate is fixed to the worktable of the press. The upper trimming base plate and the lower trimming base plate are connected by trimming guide posts. The upper trimming base plate slides above the lower trimming base plate along the trimming guide posts under the drive of the press. A cutting die is provided on the lower cutting plate, and the outer contour of the cutting die is consistent with the outer contour of the product. The cutting die is used for blanking the product. A cutting punch is fixedly provided at the bottom of the upper cutting plate, and the shape of the cutting punch is the same as the inner cavity of the product. The cutting punch slides on the upper cutting plate under the drive of the upper cutting plate. The cutting punch is used to transmit the force of the press to the product. The trimming punch has a trimming stripper plate on its periphery, and a cutter is provided at the bottom of the trimming stripper plate. The cutter has a slanted blade structure with an inclination angle of 5°. During the pressing down process of the trimming punch, the trimming stripper plate is used to position the product and press down the flash, and the cutter is used to cut the flash of the product.

[0015] In a preferred embodiment of the present invention, a cutting guide sleeve is provided between the cutting guide post and the upper cutting base plate and the lower cutting base plate. The cutting guide sleeve and the cutting guide post are used to correct the position of the cutting blade during the cutting process so that the cutting positions are the same.

[0016] In a preferred embodiment of the present invention, the trimming stripper plate is slidably mounted on the periphery of the trimming punch. A plurality of spring bolts are provided between the trimming stripper plate and the upper base plate of the trimming punch. Under the connection of the spring bolts, the trimming stripper plate can slide under the drive of the upper base plate of the trimming punch. A spring is provided on the spring bolt, and the spring connects the upper base plate of the trimming punch and the trimming stripper plate together. When the spring causes the trimming stripper plate to be pressed down to the lowest point, it rebounds.

[0017] As a preferred embodiment of the present invention, a material-coordinating bolt is further provided between the cutting stripper plate and the cutting upper bottom plate. The material-coordinating bolt is disposed between the spring bolts. The material-coordinating bolt is used to support and slide the cutting stripper plate, and at the same time, the material-coordinating bolt is used to assist in the positioning of the cutting guide sleeve and the cutting guide post.

[0018] Compared with the prior art, the present invention has the following advantages: This invention employs a pre-cutting and then forging method, combined with heat treatment of the material, to optimize the metal flow path and cavity filling behavior of the air chamber structure. It also combines a structural split forging method with rough upsetting, pre-forging, and other means to solve the problem of insufficient tensile strength and elongation caused by deep cavities, thin walls, and multiple ribs in the air chamber structure. This invention uses 6061-T6 aluminum alloy as the gas chamber forging material and provides corresponding forging and trimming dies. It increases the tensile strength of the gas chamber structure obtained by the existing forging process to 345MPa, the elongation to 12%, and the airtightness. After trimming, the burrs on the edge of the lower shell forging blank are ≤0.05mm, no secondary processing is required, the flash removal rate is 100%, the dimensional accuracy after trimming reaches IT8 level, and the surface roughness Ra≤3.2μm. This invention employs a near-net-shape forging process, which reduces machining allowance, increases material utilization to 70%, simplifies the cutting process, lowers the requirements for cutting tools, and reduces production costs. Attached Figure Description

[0019] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0020] Figure 1 A schematic flowchart of the precision forming process for the air chamber of an automotive braking system is provided for this invention. Figure 2 This invention provides a schematic diagram of the medium-roughing process for the precision forming of the air chamber of an automotive braking system; Figure 3 This invention provides a schematic diagram of the overall front structure of the upper housing; Figure 4 This invention provides a schematic diagram of the overall side structure of the upper shell; Figure 5 This invention provides a schematic diagram of the overall side view of the upper housing structure; Figure 6 This invention provides a schematic diagram of the overall side view of the lower housing structure; Figure 7 This invention provides a top view of the overall structure of the lower housing; Figure 8 This invention provides a schematic diagram of the upper die model structure of the upper shell pre-forging mold; Figure 9 This invention provides a schematic diagram of the lower die model structure of the upper shell pre-forging mold; Figure 10 This invention provides a schematic diagram of the upper die model structure of the final forging die for the upper shell; Figure 11 This invention provides a schematic diagram of the lower die model structure of the upper shell final forging die; Figure 12 This invention provides a schematic diagram of the lower die model structure of the lower shell final forging die; Figure 13 A schematic diagram of the upper die model structure of the final forging die for the shell is provided for this invention; Figure 14 This invention provides a side view schematic diagram of the final forging die for the lower housing. Figure 15 This invention provides an integrated forging apparatus for pre-forging and final forging of irregularly shaped cavities; Figure 16 Provided for the present invention Figure 15 The schematic diagram of the rotating mechanism in the embodiment shown is as follows; Figure 17 This invention provides a schematic diagram of the pre-forged upper cavity in the embodiment shown in Figure 15; Figure 18 A top view of the forging base in the embodiment shown in Figure 15 is provided for the present invention. Figure 19 A side view of the edge-cutting device is provided for this invention. Figure 20 Provided for the present invention Figure 19 A cross-sectional view of the cutting device in the embodiment shown.

[0021] The labels in the diagram represent the following: 101 - Upper die of lower shell final forging mold; 102 - Lower die of lower shell final forging mold; 103 - Lifting hole; 1-Upper die holder, 11-Pre-forging upper cavity, 12-Final forging upper cavity; 2-Lower die holder, 21-Pre-forging lower cavity, 22-Final forging lower cavity, 23-Rotating shaft, 24-Baffle; 3-Forged base, 31-Bracket, 32-Rotating hole, 33-Mounting cavity, 34-Guide post; 4-First press; 5-Suction cup, 51-Airflow channel, 52-Conical opening, 53-Sealing gasket, 54-Y-type hose, 55-Negative pressure equipment, 56-Positive pressure equipment, 57-Three-way solenoid directional valve; 61-Motor, 62-Driving wheel, 63-Driven wheel; 71-Positioning block, 72-Positioning rod, 73-Positioning groove; 81-Limit block, 82-Limit hole; 201 - Upper base plate for trimming; 202 - Trimming punch; 203 - Trimming stripper plate; 204 - Trimming die; 205 - Lower base plate for trimming; 206 - Trimming guide bushing; 207 - Trimming guide post; 208 - Spring bolt; 209 - Material bolt. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The function of the brake chamber is to convert the pressure of compressed air into the mechanical force that rotates the brake camshaft, thus achieving the braking action. When a car brakes, air enters the brake chamber through the air inlet. Under the action of air pressure, the diaphragm deforms, pushing the push rod and driving the brake adjusting arm to rotate the brake cam, pressing the brake shoe friction pads against the brake drum to generate braking. Structurally, the chamber is a thin-walled, bowl-shaped component with a small overall draft angle and a complex shape.

[0024] In order to obtain automotive braking system air chambers with low porosity, thin walls that are not easily deformed, and a low rate of rib folding defects, such as... Figure 1 As shown, the present invention provides a precision forming process for an automotive braking system air chamber, comprising the following steps: S100. The original blank is cut into two parts by split forging to obtain the upper shell blank and the lower shell blank. S200. Perform the first heat treatment on the upper shell blank and the lower shell blank respectively, and perform upsetting treatment on the upper shell blank and the lower shell blank until the diameter of the upper shell blank is the same as the diameter of the upper mold cavity and the diameter of the lower shell blank is the same as the diameter of the lower mold cavity, to obtain the upper upsetting blank and the lower upsetting blank. S300: The upper upsetting billet is placed into the upper shell pre-forging die for pre-forging using the first press, and then placed into the upper shell final forging die for final forging to obtain the upper shell final forging billet; S400: The first press is used to place the lower upsetting billet into the lower shell final forging die for final forging to obtain the lower shell final forging billet. The edge trimming die is used to trim the lower shell final forging billet to obtain the lower shell forging blank. S500: Perform a second heat treatment on the final forging blank of the upper shell and the forging blank of the lower shell to obtain the upper shell forging and the lower shell forging of the gas chamber.

[0025] Select upper shell blank, This invention, through structural analysis, divides the entire air chamber product into an upper shell and a lower shell. The overall structure of the upper shell is as follows: Figure 3 , Figure 4 and Figure 5 As shown, the overall structure of the lower shell is as follows: Figure 6 , Figure 7As shown, in order to obtain the finished upper and lower shells, the present invention forges the above materials according to their different structural characteristics.

[0026] Specifically, the production process for the upper shell is as follows: Select a suitable raw material for producing the upper shell blank, and use a high-speed aluminum saw to cut the raw material into simple pieces to obtain the upper shell blank; The upper shell blank undergoes a first heat treatment, followed by rough upsetting. The specific process for the rough upsetting of the upper shell is detailed below. Figure 2 As shown, the process continues until the diameter of the upper shell blank is the same as the diameter of the upper mold cavity, thus obtaining the upper upsetting blank. The upper upsetting billet is placed into the upper shell pre-forging die for pre-forging using a first press, and then placed into the upper shell final forging die for final forging to obtain the upper shell final forging billet. The final forging billet of the upper shell is subjected to a second heat treatment to obtain the finished part (the upper shell forging of the air chamber).

[0027] Unlike existing technologies, this invention first uses a hydraulic press to upset the initial cylindrical blank after simple cutting, so that the upset diameter is close to the cavity diameter. This fixes the position of the blank relative to the mold cavity during the subsequent forging process. In addition, a pre-forging process is added, which to some extent solves the problem that the upper shell has ribs and is difficult to forge in one go.

[0028] After upsetting, the billet is more easily positioned in the mold cavity during forging, making it easier for the workpiece to follow the mold shape during forging. This optimizes the metal flow path and mold cavity filling behavior, solving production problems such as high porosity and folding defects caused by difficulties in material rheology control and precise coordination of filling of multi-ribbed structures in existing technologies. The resulting samples have good morphology and performance, solving the forming problem of deep cavity, thin wall, and multi-ribbed complex air chamber structures.

[0029] The production process for the lower shell is as follows: Select a suitable raw material for producing the lower shell blank, and use a high-speed aluminum saw to cut the raw material into simple pieces to obtain the lower shell blank; The lower shell blank undergoes a first heat treatment, followed by rough upsetting until the diameter of the lower shell blank is the same as the diameter of the lower mold cavity, thus obtaining the lower upsetting blank. The first press is used to put the lower upsetting billet into the lower shell final forging die for final forging to obtain the lower shell final forging billet. The lower shell final forging billet is trimmed by the trimming die to obtain the lower shell forging blank. The lower shell forging billet is subjected to a second heat treatment to obtain the finished part (gas chamber lower shell forging).

[0030] The production process of the lower shell is different from that of the upper shell. The main reasons are as follows: (1) In the process of structural division, the complex structure is divided into the upper shell. The upper shell contains a lot of thick ribs and thin walls, so it needs to be pre-forged. The structure of the lower shell is simpler and does not need to be pre-forged, thereby reducing production costs. (2) The upper shell is more compatible with the original blank, so it does not need to be trimmed. In order to reduce the cutting process and cost in the early stage and reduce tool loss, the lower shell needs to be trimmed during production.

[0031] Similar to the upper shell, the lower shell also uses a rough upsetting process for forging. The reason for this is the same as for the upper shell: to make it easier to position the material in the mold cavity during the forging process, so that the lower upsetting billet can be accurately shaped in the final forging mold of the lower shell.

[0032] This invention divides the air chamber of the automotive braking system into structures with different structural features, and uses different forging processes to forge each structure. This not only results in a more precise automotive braking system air chamber, but also reduces the pre-processing of materials before forging, thereby reducing the difficulty of material cutting and tool wear, and also reduces material loss and lowers production costs.

[0033] The present invention further employs heat treatment, rough upsetting, and pre-forging to perform precision processing on the upper shell, so that the upper shell blank can be more accurately positioned in the mold cavity during the forging process. This solves the forming problem of deep cavity, thin wall, and multi-rib complex air chamber structure to a certain extent, thereby realizing the precision forging of air chamber structure.

[0034] In this invention, the original blank is aluminum alloy 6061-T6. Aluminum alloy 6061-T6 is a high-quality alloy, which is more conducive to improving the airtightness and tensile strength of the air chamber structure.

[0035] When selecting a suitable initial blank thickness, aluminum alloy 6061-T6 itself has specific specifications. The diameter of the 6061 extruded bar is less than 100mm. Selecting different specifications of aluminum alloy 6061-T6 affects the forging cost. In order to make the forming process more precise and reduce material consumption, this invention further provides the following roughing process steps: In step S200, the upsetting process includes the following steps: S201. Heat the upper shell blank to 520±10℃, place it in the upper shell upsetting mold, and apply axial pressure to the upper shell blank through a hydraulic press to increase the blank diameter from 90mm to 200mm and compress the height from 110mm to 35mm, with a deformation of 68%. After upsetting, the surface of the blank is sprayed with graphite lubricant (thickness 0.05mm) to reduce the frictional resistance of subsequent forging. S202. Heat the lower shell blank to 520±10℃ and place it in the upper shell upsetting mold. Apply axial pressure to the upper shell blank using a hydraulic press to increase the blank diameter from 90mm to 120mm and compress the height from 85mm to 45mm, with a deformation of 47%. After upsetting, spray graphite lubricant (0.05mm thick) onto the surface of the blank to reduce the frictional resistance of subsequent forging.

[0036] Before upsetting, a first heat treatment is required. In the preferred embodiment, the temperature of the first heat treatment is 500-525℃ and the holding time is 1.5-2h.

[0037] After rough upsetting, the upper and lower upset billets need to be forged separately. The upper upset billet requires pre-forging and final forging, while the lower upset billet is directly forged. In this invention, the same forging conditions are used for both pre-forging and final forging. The difference lies in the dies used for pre-forging and final forging of the upper upset billet, and the dies used for final forging of the lower upset billet are different from those used for the upper upset billet.

[0038] Specifically, the pre-forging and final forging include the following conditions: the press is a 2500t electric screw press, the impact energy is 150kJ, and the impact speed is 0.8m / s, to ensure that the ribs and thin walls are fully formed.

[0039] Unlike the upper shell, the lower shell requires edge trimming because the initial cutting process is a rough cut. The edge trimming process includes the following steps: S401. Cool the lower shell final forging billet to below 150°C and place the lower shell final forging billet in the trimming device; S402. The lower shell final forging billet is trimmed using a second press at a shearing speed of 10 mm / s. The flash thickness is <0.5 mm and the burr on the edge of the billet is ≤0.05 mm. The second press is a 400t mechanical press.

[0040] After forging and trimming the workpiece, based on the material properties of aluminum alloy 6061-T6, this invention further performs a second heat treatment on the final forging blank of the upper shell and the forging blank of the lower shell to achieve surface work hardening and smoothness. Specifically, this includes the following steps: The upper shell final forging billet and the lower shell forging billet were solution treated at 530℃, held at the temperature for 3 hours, quenched with room temperature water, and held at 175℃ for 8 hours in an aging furnace to obtain the forging billet. The forging blank is subjected to water cooling, etching, pickling and shot blasting processes to obtain forgings with work hardening and smooth surface.

[0041] like Figures 8 to 14As shown, the present invention further provides a mold adapted to the above-mentioned precision forming process of the air chamber of the automotive braking system, wherein, Figure 8 This is a schematic diagram of the upper die model structure of the pre-forging mold for the upper shell; Figure 9 This is a schematic diagram of the lower die model of the upper shell pre-forging mold; Figure 10 This is a schematic diagram of the upper die model structure of the final forging die for the upper shell; Figure 11 This is a schematic diagram of the lower die model of the final forging die for the upper shell; Figure 12 This is a schematic diagram of the lower die model structure of the final forging die for the lower shell. Figure 13 This is a schematic diagram of the upper die model of the final forging mold for the lower shell. Figure 14 This is a side view of the final forging die for the lower shell.

[0042] Figure 14 This is the closed state of the upper die 101 and lower die 102 of the lower shell final forging die. The lifting hole 103 is for convenient fixing of the die during transportation and installation. The aforementioned final forging die adopts an open forging cavity with a cavity depth of 80mm. It includes a deep cavity with a thin wall (average wall thickness of 4mm) and a lower shell of the gas chamber. The die material is 5CrMnMo hot work die steel with surface nitriding treatment (hardness ≥60HRC). The surface roughness of the die cavity is Ra≤0.4μm. The die is preheated to 200±20℃ to reduce thermal shock and optimize material filling.

[0043] like Figure 15 As shown, this invention provides an embodiment of an integrated forging device for irregularly shaped cavities, specifically a pre-forging upper cavity 12 and a final forging upper cavity 13 integrated into an upper die base 1, and a pre-forging lower cavity 21 and a final forging lower cavity 22 correspondingly integrated into a lower die base 2. A suction cup 5 within the pre-forging upper cavity 12 is used to adsorb the pre-forged part, allowing the lifting die to remove the pre-forged part from the pre-forging lower cavity 21. A rotating mechanism drives the lower die base 2 to rotate, positioning the final forging lower cavity 22 below the pre-forging upper cavity 12, releasing the pre-forged part into the final forging lower cavity 22. The lower die base 2 then rotates back, positioning the final forging lower cavity 22 below the final forging upper cavity 13, thus completing the final forging operation.

[0044] In this embodiment, it is mainly used for forging the upper housing of the air chamber of the automobile braking system.

[0045] Among them, the pre-forging upper cavity 12 and the final forging upper cavity 13 are punches, and the pre-forging lower cavity 21 and the final forging lower cavity 22 are dies; the pre-forging upper cavity 12 and the final forging upper cavity 13 are symmetrically arranged along the central axis of the upper die holder 1, and the pre-forging lower cavity 21 and the final forging lower cavity 22 are symmetrically arranged along the rotation axis 23 of the lower die holder 2. The center line of the upper die holder 1 coincides with the rotation axis of the lower die holder 2, which lays the foundation for the accurate alignment of the cavities after the lower die holder 2 rotates.

[0046] The forged base 3 is a rectangular platform structure.

[0047] The central area of ​​the upper surface of the forging base 3 is the mounting area of ​​the lower die base 2. A rotating hole 32 is opened at the center of the mounting area of ​​the lower die base 2 along the setting direction. The lower die base 2 is provided with a rotating shaft 23 vertically downward at the geometric center point between the pre-forging lower cavity 21 and the final forging lower cavity 22. The rotating shaft 23 is clearance-fitted with the rotating hole 32.

[0048] The upper surface of the forging base 3 is provided with a portal bracket 31 that covers the lower die base 2 directly above it, for mounting the first press 4.

[0049] The forging base 3 has an internal mounting cavity 33 for mounting the rotating mechanism.

[0050] The first press 4 is vertically mounted on the support 31. The movable end of the first press 4 is connected to the upper die base 1, so that the upper die base 1 is located above the lower die base 2, and the pre-forging upper cavity 12, the pre-forging lower cavity 21, the final forging upper cavity 13, and the final forging lower cavity 22 correspond one-to-one in the vertical direction.

[0051] The first press 4 adopts a hydraulically driven structure, equipped with two hydraulic cylinders. The hydraulic cylinders are vertically fixed on the lower surface of the crossbeam of the support 31. The lower end of the piston rod is connected to the upper surface of the upper die seat 1 through a quick-release flange. The hydraulic system includes an oil tank, a hydraulic pump, an overflow valve, a solenoid valve 57, etc. The extension or retraction of the piston rod is controlled by the solenoid valve 57 to realize the pressing down or lifting of the upper die seat 1. The die closing pressure is adjusted by the overflow valve. The pre-forging pressure is usually 10-20MPa, and the final forging pressure is usually 25-40MPa.

[0052] The suction cup 5 is set on the inner wall of the pre-forging upper cavity 12. The upper mold base 1 is provided with an airflow channel 51 connected to the suction cup 5. The airflow channel 51 is connected to an external negative pressure device 55. The suction cup 5 is used to adsorb the pre-forging part.

[0053] The rotating mechanism is located in the mounting cavity 33 within the forging base 3. The rotating mechanism drives the lower die holder 2 to rotate in the horizontal direction, so that the final forging lower cavity 22 can move between directly below the pre-forging upper cavity 12 and directly below the final forging upper cavity 13.

[0054] Specifically, Pre-forging stage: The lower die holder 2 is in the initial position, that is, the pre-forging lower cavity 21 is located directly below the pre-forging upper cavity 12. The initial forging material is placed into the pre-forging lower cavity 21, and the first press 4 drives the upper die holder 1 to press down. The pre-forging upper cavity 12 and the pre-forging lower cavity 21 are closed, and the pre-forging is completed. Transfer stage: The upper die holder 1 is raised, and at the same time the negative pressure device 55 is started. The suction cup 5 adsorbs the pre-forged part after pre-forging. The rotating mechanism drives the lower die holder 2 to rotate 180°. The final forging lower cavity 22 rotates to directly below the pre-forging upper cavity 12. The negative pressure device 55 stops, and the pre-forged part is released and falls into the final forging lower cavity 22. Final forging stage: The rotating mechanism drives the lower die holder 2 to rotate 180° again, and the lower forging cavity 22 rotates to be directly below the upper forging cavity 13. The first press 4 drives the upper die holder 1 to press down, and the upper forging cavity 13 and the lower forging cavity 22 close together, completing the final forging. Reset phase: The upper die holder 1 is lifted to remove the finished forging after final forging, and the lower die holder 2 is reset to the initial position to enter the next forging cycle.

[0055] Furthermore, in conjunction with the characteristic that the lower die holder 2 rotates 180°, allowing the final forging lower cavity 22 to move between directly below the pre-forging upper cavity 12 and directly below the final forging upper cavity 13, in this embodiment, the cavity directions of the pre-forging upper cavity 12 and the pre-forging lower cavity 21 are exactly opposite to the cavity directions of the final forging upper cavity 13 and the final forging lower cavity 22, so that the final forging lower cavity 22 remains consistent with the cavity direction of the pre-forging upper cavity 12 or the final forging upper cavity 13 after rotating 180°.

[0056] This embodiment also provides an example of a rotating mechanism.

[0057] like Figure 16 As shown, the rotating mechanism includes a motor 61, a drive wheel 62 is provided on the output shaft of the drive motor 61, a driven wheel 63 is provided on the rotating shaft 23, the forging base 3 is provided with a mounting cavity 33 in the vertical direction, the motor 61 is provided in the mounting cavity 33, and the drive wheel 62 and the driven wheel 63 are engaged.

[0058] The drive motor 61 is a servo motor 61, which has a precise rotation angle control function with a control accuracy of ±0.1°; the rotation angle can be set to 180° through the controller.

[0059] The driving gear has a module of 2-3 and 20-30 teeth. The driven gear has the same module as the driving gear and 40-60 teeth. The two gears mesh and transmit power with a reduction ratio of 2:1, which reduces the speed and increases the torque, ensuring that the lower mold base 2 rotates smoothly. Furthermore, a baffle 24 is provided around the lower die holder 2, and the driving wheel 62 and the driven wheel 63 are arranged in the space formed by the baffle 24 to prevent oxide scale and dust from entering the gear meshing area during the forging process and affecting the transmission accuracy.

[0060] In order to improve the positioning accuracy of the final forging lower cavity 22, which can move between the pre-forging upper cavity 12 and the final forging upper cavity 13, the following embodiments are also provided in this embodiment.

[0061] like Figure 17 As shown, a positioning block 71 extends outward from the side of the lower die base 2 in the horizontal direction. Two positioning rods 72 are vertically arranged on the movement trajectory of the positioning block 71 on the forging base 3. The positions of the two positioning rods 72 are set such that when the positioning block 71 contacts the two positioning rods 72 respectively, the final forging lower cavity 22 is located directly below the pre-forging upper cavity 12 and the final forging upper cavity 13, which can further improve the mold closing accuracy between the upper cavity and the lower cavity.

[0062] A positioning groove 73 is provided on each side of the positioning block 71. The two positioning grooves 73 correspond one-to-one with the two positioning rods 72 and can be engaged with each other. The end of the positioning groove 73 can be magnetically attracted to the positioning rod 72, forming a double constraint with mechanical engagement.

[0063] This allows the current mold base 2 to rotate to a position close to the positioning rod 72 under the drive of the servo motor 61. If there is an angular error in the servo motor 61, it can be corrected by magnetic force to achieve active alignment between the positioning groove 73 and the positioning rod 72 instead of passive jamming.

[0064] Furthermore, during mechanical clamping, there is an assembly gap between the positioning groove 73 and the positioning rod 72. The magnetic attraction force can tightly attract the positioning rod 72 to the end of the positioning groove 73, completely eliminating the gap and fixing the position of the lower mold base 2.

[0065] This implementation also provides the following examples.

[0066] The lower die holder 2 is provided with a limiting block 81 vertically upward, which is used to abut against the upper die holder 1 when the pre-forging upper cavity 12 moves toward the final forging lower cavity 22 to release the pre-forging part, so that there is a gap between the upper die holder 1 and the lower die holder 2, so as to avoid the pre-forging upper cavity 12 and the final forging lower cavity 22 closing and causing wear to the pre-forging part.

[0067] Meanwhile, since there is a gap between the upper die holder 1 and the lower die holder 2, the pre-forging part can slightly adjust its position by its own gravity after the negative pressure is released, ensuring that the center of the pre-forging part is aligned with the center of the final forging lower cavity 22.

[0068] Specifically, 2-4 limit blocks 81 are symmetrically arranged along the rotation axis of the lower mold base 2. The top of the limit block 81 is provided with an arc transition surface instead of a sharp end face. On the one hand, this avoids scratching the lower surface of the upper mold base 1 during contact; on the other hand, it reduces stress concentration and prevents the top crack caused by high frequency contact.

[0069] Furthermore, in order to enable the upper mold base 1 and the lower mold base 2 to close properly, in this embodiment, the upper mold base 1 is provided with a limiting hole (not shown in the figure) that can engage with the limiting block 81. The position of the limiting hole is set such that when the final forging lower cavity 22 rotates to directly below the final forging upper cavity 13, the limiting hole is exactly above the limiting block 81, so as to avoid the limiting block 81 restricting the closing of the upper mold base 1 and the lower mold base 2.

[0070] At the same time, the limiting block 81 and the limiting hole work together to guide the closing of the upper mold base 1 and the lower mold base 2, thereby improving the positioning accuracy.

[0071] Specifically, the limiting block 81 and the limiting hole are both tapered structures with the larger end at the bottom and the smaller end at the top, so as to facilitate positioning of the two during the mold closing process.

[0072] Furthermore, in order to improve the accuracy of the mold closing between the upper mold base 1 and the lower mold base 2, two guide pillars 34 are symmetrically provided between the top of the bracket 31 and the forging base 3, and the guide pillars 34 penetrate the upper mold base 1, and the upper mold base 1 moves up and down along the guide pillars 34.

[0073] This embodiment provides the following examples for suction cup 5.

[0074] like Figure 18 As shown, the suction cup 5 is a conical opening 52 that is set inside the upper mold base 1 and connects the airflow channel 51 and the pre-forged upper cavity 12, rather than a traditional flat suction cup 5.

[0075] Specifically, the cone angle is usually controlled between 60° and 90°. If the cone angle is too small, it will easily lead to local stress concentration on the surface of the pre-forged part, while if it is too large, the adsorption contact area will be insufficient. The diameter of the large end of the cone-shaped opening 52 is 8-15mm, and the diameter of the small end is 4-8mm. The depth of the cone-shaped opening 52 is 5-10mm to ensure that the channel length is sufficient to form a stable negative pressure field, while avoiding the accumulation of material on the inner wall of the channel due to excessive depth.

[0076] A flexible graphite sealing gasket 53 is provided around the end of the conical opening 52 that is in contact with the pre-forging part, which serves as a flexible sealing interface between the conical opening 52 and the pre-forging part.

[0077] The sealing gasket 53 has an annular structure. An annular groove is opened at the edge of the large end of the conical opening 52. After the sealing gasket 53 is embedded in the annular groove, it is fixed with high-temperature epoxy resin adhesive with a temperature resistance of ≥250℃. The upper surface of the sealing gasket 53 is flush with the large end of the conical opening 52 to avoid protrusions that hinder the fitting of the pre-forged parts or depressions that cause air leakage.

[0078] Flexible graphite can withstand long-term operating temperatures of over 450℃, and the contact between the sealing gasket 53 and the high-temperature forging is not continuous: after pre-forging, the total time for adsorbing the pre-forging part and rotating the lower die 2 is about 2-3 seconds, and the contact is immediately broken after release; the short contact time prevents heat from accumulating on the sealing gasket 53 and avoids the temperature from continuously rising.

[0079] Furthermore, the inner wall of the pre-forging upper cavity 12 is provided with multiple suction cups 5, and the ends of the corresponding multiple airflow channels 51 converge into a connection port. This connection port is connected to a Y-shaped hose 54. One end of the Y-shaped hose 54 is connected to an external negative pressure device 55, and the other end is connected to an external positive pressure device 56. An electromagnetic reversing valve 57 is provided at the three-way passage of the Y-shaped hose 54 to realize the switching between negative pressure and positive pressure at the suction cups 5.

[0080] Solenoid directional valve 57 is a two-position three-way solenoid directional valve; negative pressure equipment 55 uses a rotary vane vacuum pump with a pumping speed of 10-20m / s. 3 / h, ultimate vacuum degree ≤ -0.095MPa, ensuring that stable negative pressure can be quickly established at suction cup 5; positive pressure equipment 56 uses an oil-free air compressor with an output pressure of 0.3-0.5MPa and a flow rate of 0.1-0.2m³ / h. 3 / min, the positive pressure does not need to be too high, to avoid impacting the pre-forged parts and causing deformation. It is only necessary to assist in breaking the negative pressure and pushing the pre-forged parts away from the suction cup 5.

[0081] The switching between three states—negative pressure adsorption, positive pressure release, and normal pressure standby—is achieved through the valve core action of the electromagnetic reversing valve 57. The specific process is deeply integrated with the equipment transfer process. State 1: Transfer stage after negative pressure adsorption of pre-forged parts After pre-forging is completed, the controller issues an adsorption command, the valve core of the electromagnetic reversing valve 57 switches to the state of connection between the airflow channel 51 and the negative pressure device 55, the vacuum pump starts, and the airflow passes through the negative pressure branch of the Y-type hose 54 → three-way valve → airflow channel 51 → conical mouth 52 suction cup 5, quickly removing the air between the suction cup 5 and the pre-forged part, and the pre-forged part is firmly adsorbed in the pre-forging upper cavity 12; then the upper die seat 1 is lifted, and the pre-forging upper cavity 12 and the pre-forging lower cavity 21 are separated.

[0082] State 2: Positive pressure release pre-forging stage - the pre-forging part falls into the lower cavity of the final forging. The lower die holder 2 rotates 180°, and the final forging lower cavity 22 moves to directly below the pre-forging upper cavity 12. The upper die holder 1 descends to the limit block 81 and abuts. The controller issues a release command, and the valve core of the electromagnetic reversing valve 57 switches to the state of connection between the airflow channel 51 and the positive pressure device 56. The air compressor outputs positive pressure airflow, which passes through the positive pressure branch of the Y-type hose 54 → three-way valve → airflow channel 51 → conical port 52 suction cup 5, quickly breaking the negative pressure at the suction cup 5. At the same time, the positive pressure airflow pushes the pre-forging part to move towards the final forging lower cavity 22, ensuring that the pre-forging part falls smoothly into the final forging lower cavity 22 under the combined action of gravity and positive pressure.

[0083] State 3: Atmospheric pressure standby non-adsorption / release stage After the pre-forged parts are released or when the device is in standby mode, the position of the valve core of the electromagnetic reversing valve 57 is not restricted, and the vacuum pump and air compressor are shut down.

[0084] The integrated forging device for irregularly shaped cavities, provided by this invention, integrates the upper forging cavity and the upper forging cavity of the pre-forging die base, and the lower forging cavity and the lower forging cavity of the pre-forging die base. A suction cup within the upper forging cavity adsorbs the pre-forged part, allowing the lifting die to remove the pre-forged part from the lower forging cavity. A rotating mechanism drives the lower die base to rotate, positioning the lower forging cavity below the upper forging cavity, releasing the pre-forged part into it. The lower die base then rotates, positioning the lower forging cavity below the upper forging cavity to complete the final forging operation. This integrates the traditional three steps of pre-forging, transfer, and final forging, requiring two separate machines, into a single continuous operation, accelerating the production cycle of upper shell forging.

[0085] like Figure 19 and Figure 20 As shown, the present invention further provides a trimming device, including an upper trimming base plate 201 and a lower trimming base plate 205. The upper trimming base plate 201 is fixed to the slider of the press. The press is a second press, specifically a 400t mechanical press.

[0086] The lower cutting plate 205 is fixed to the press worktable. The upper cutting plate 201 is connected to the lower cutting plate 205 through the cutting guide post 207. The upper cutting plate 201 slides above the lower cutting plate 205 along the cutting guide post 207 under the drive of the press.

[0087] A trimming die 204 is provided on the lower trimming base plate 205. The outer contour of the trimming die 204 is consistent with the outer contour of the product. The trimming die 204 is used for blanking the product. A trimming punch 202 is fixedly provided at the bottom of the upper trimming base plate 201. The shape of the trimming punch 202 is the same as the inner cavity of the product. The trimming punch 202 slides on the upper trimming base plate 201 under the drive of the upper trimming base plate 201. The trimming punch 202 is used to transmit the force of the press to the product.

[0088] When the upper bottom plate 201 of the trimming edge is running at the bottom, the trimming punch 202 is fitted inside the trimming die 204. The structure of the trimming punch 202 is the same as the upper die model of the lower shell final forging die, and the structure of the trimming die 204 is the same as the lower die model of the lower shell final forging die.

[0089] The trimming punch 202 is provided with a trimming stripper plate 203 on its periphery, and a cutter 210 is provided at the bottom of the trimming stripper plate 203. The cutter 210 has a slanted blade structure with an inclination angle of 5°. During the pressing down process of the trimming punch 202, the trimming stripper plate 203 is used to position the product and press down the flash, and the cutter 210 is used to cut the flash of the product.

[0090] In the trimming die structure, the trimming die is matched with the final forging die of the lower shell, and its cutting edge clearance is set to 0.1mm. It adopts a slanted blade structure (tilt angle 5°) to reduce shearing force.

[0091] The mold is made of SKD11 cold work mold steel with a hardness of 62-64HRC and is titanium-plated to extend its lifespan.

[0092] The above-mentioned products are the lower shell final forging billets or the upper shell final forging billets. If it is an upper shell final forging billet, the corresponding mold shape is the same as the upper mold model structure of the upper shell final forging mold and the lower mold model structure of the upper shell final forging mold.

[0093] A cutting guide sleeve 206 is provided between the cutting guide post 207 and the upper cutting base plate 201 and the lower cutting base plate 205. The cutting guide sleeve 206 and the cutting guide post 207 are used to correct the position of the cutter 210 during the cutting process so that the cutting positions are the same.

[0094] The trimming stripper plate 203 is slidably installed on the periphery of the trimming punch 202. Several spring bolts 208 are provided between the trimming stripper plate 203 and the trimming upper base plate 201. Under the connection of the spring bolts 208, the trimming stripper plate 203 can slide under the drive of the trimming upper base plate 201. The spring bolts 208 are provided with springs, which connect the trimming upper base plate 201 and the trimming stripper plate 203 together. When the spring drives the trimming stripper plate 203 to be pressed down to the lowest point, it rebounds.

[0095] The springback of the spring bolt 208 occurs after shearing. The springback can reduce the impact damage of the cutting edge when it hits the lowest point, thus extending the life of the shearing device.

[0096] A material-coordinating bolt 209 is also provided between the trimming stripper plate 203 and the trimming upper base plate 201. The material-coordinating bolt 209 is located between the spring bolts 208. The material-coordinating bolt 209 is used to support and slide the trimming stripper plate 203. At the same time, the material-coordinating bolt 209 is used to assist in the positioning of the trimming guide sleeve 206 and the trimming guide post 207.

[0097] The shearing device disclosed in this invention can quickly trim the edges of the final forged blank. Compared with milling, turning and other techniques, the cutting tool in this device has springback protection, which can spring back after trimming to prevent collision, thereby improving the service life of the cutting tool.

[0098] Based on the above method and the corresponding mold and trimming device, the present invention provides an embodiment: Example 1: 1. Selecting materials: (1) The original blank material is aluminum alloy 6061-T6 material bar. The weight of the original blank material of the upper shell is 1.889kg and the blank material is φ90*110. The weight of the original blank material of the lower shell is 1.45kg and the blank material is φ90*85. The original blank was cut using a high-speed aluminum saw to obtain an upper shell blank and a lower shell blank. The upper shell blank weighed 1.505 kg with a residual value of 0.384 kg, and the lower shell blank weighed 991 g with a residual value of 0.459 kg. The weight tolerance was controlled within ±0.5%. (2) Heat the upper shell blank and the lower shell blank to 500-525℃ (within the recrystallization temperature range of aluminum alloy), hold for 1.5-2 hours, and the furnace exit time is about 30 seconds; (3) The billet is clamped into the roughing mold and the upper shell blank is upset using a hydraulic press. Axial pressure is applied by the hydraulic press to increase the diameter of the billet from 90mm to 200mm and compress the height from 110mm to 35mm, with a deformation of about 68%. After upseting, graphite lubricant (thickness 0.05mm) is sprayed on the surface of the upset billet to reduce the frictional resistance of subsequent forging. The lower shell blank will be upset using a hydraulic press. Axial pressure will be applied by the hydraulic press to increase the diameter of the blank from 90mm to 120mm and compress the height from 85mm to 45mm, with a deformation of about 47%. After upsetting, the surface of the blank will be sprayed with graphite lubricant (0.05mm thick) to reduce the frictional resistance of subsequent forging. At this point, the diameter of the upper shell blank is the same as the diameter of the upper mold cavity, and the diameter of the lower shell blank is the same as the diameter of the lower mold cavity, thus obtaining the upper upsetting blank and the lower upsetting blank. The blank size after upsetting the upper shell is approximately φ200*35; the blank size after upsetting the lower shell is approximately φ120*50. (4) Use the transfer assembly to clamp the upper upsetting billet to the lower die of the upper shell pre-forging mold. Use a 2500t electric screw press to put the upper upsetting billet into the upper shell pre-forging mold for pre-forging. The impact energy is 150kJ and the impact speed is 0.8m / s. Then put it into the upper shell final forging mold for final forging. The impact energy is 150kJ and the impact speed is 0.8m / s to obtain the upper shell final forging billet. (5) Use the transfer assembly to clamp the lower upsetting billet to the lower die of the pre-forging mold of the lower shell, and use a 2500t electric screw press to put the lower upsetting billet into the final forging mold of the lower shell for final forging. The impact energy is 150kJ and the impact speed is 0.8m / s to obtain the final forging billet of the lower shell. (6) The lower shell final forging billet is trimmed using a trimming die. The blade gap is set to 0.1mm, and a slanted blade structure (inclination angle 5°) is adopted. The lower shell final forging billet is cooled to below 150℃ and placed in a trimming device. A 400t mechanical press is used for trimming, with a shearing speed of 10mm / s. The flash thickness is controlled within 0.5mm to obtain the lower shell forging billet. (7) Take the above-mentioned upper shell final forging billet and lower shell forging blank, set the solution temperature to 530℃, hold it for 3 hours after reaching the temperature, quench it with room temperature water, put it into the aging furnace and set the temperature to 175℃, hold it for 8 hours after reaching the temperature; the surface treatment process is to water cool, etch, pickle and shot blast the forging blank to obtain forgings with work hardening and surface smoothness.

[0099] The characterization results are as follows: (1) Material utilization rate During the simple cutting process, the material utilization rate of the upper shell blank was 79.6%, and the material utilization rate of the lower shell blank was 68%, which is a relatively high material utilization rate.

[0100] (2) Edge trimming effect After trimming, the burrs on the edge of the forged blank of the lower shell are ≤0.05mm, requiring no secondary processing. The flash removal rate is 100%, and the dimensional accuracy after trimming reaches IT8 level, with a surface roughness Ra≤3.2μm.

[0101] (3) Performance of finished products The tensile strength increased from 240MPa in the forging process to 345MPa (an increase of 43.8%), the elongation increased from 6% to 12%, and the airtightness was significantly improved.

[0102] The precision forming process and forging device for the automotive braking system air chamber in this embodiment can optimize the metal flow path and cavity filling behavior to solve the forming problem of complex air chamber structures with deep cavities, thin walls, and multiple ribs. Through near-net-shape forging process, the machining allowance is minimized, the material utilization rate is increased to 70%, the tensile strength of the finished part is increased to 345MPa, the elongation is increased to 12%, and it has good air tightness.

[0103] The above embodiments are merely exemplary embodiments of this application and are not intended to limit this application. The scope of protection of this application is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to this application within its substance and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this application.

Claims

1. A precision forming process for an automotive braking system air chamber, characterized in that, Includes the following steps: S100. The original blank is cut into two parts by split forging to obtain the upper shell blank and the lower shell blank. S200. Perform a first heat treatment on the upper shell blank and the lower shell blank respectively, and perform upsetting treatment on the upper shell blank and the lower shell blank until the diameter of the upper shell blank is the same as the diameter of the upper mold cavity and the diameter of the lower shell blank is the same as the diameter of the lower mold cavity, to obtain the upper upsetting blank and the lower upsetting blank. S300. The upper upsetting billet is placed into the upper shell pre-forging mold for pre-forging using a first press, and then placed into the upper shell final forging mold for final forging to obtain the upper shell final forging billet. S400. The lower upsetting billet is placed into the lower shell final forging die by the first press for final forging to obtain the lower shell final forging billet. The lower shell final forging billet is trimmed by the trimming die to obtain the lower shell forging blank. S500, the upper shell final forging blank and the lower shell forging blank are subjected to a second heat treatment to obtain the upper shell forging and the lower shell forging of the gas chamber.

2. The precision forming process for an automotive braking system air chamber according to claim 1, characterized in that, The original blank was aluminum alloy 6061-T6.

3. The precision forming process for an automotive braking system air chamber according to claim 2, characterized in that, In step S200, the upsetting process includes the following steps: S201. Heat the upper shell blank to 520±10℃, place it in the upper shell upsetting mold, and apply axial pressure to the upper shell blank through a hydraulic press to increase the blank diameter from 90mm to 200mm and compress the height from 110mm to 35mm, with a deformation of 68%. After upsetting, the surface of the blank is sprayed with graphite lubricant. S202. The lower shell blank is heated to 520±10℃ and placed in the upper shell upsetting mold. Axial pressure is applied to the upper shell blank by a hydraulic press, so that the blank diameter increases from 90mm to 120mm and the height is compressed from 85mm to 45mm, with a deformation of 47%. After upsetting, graphite lubricant is sprayed on the surface of the blank.

4. The precision forming process for an automotive braking system air chamber according to claim 1, characterized in that, The pre-forging and the final forging satisfy the following conditions: the press is a 2500t electric screw press with an impact energy of 150kJ and an impact speed of 0.8m / s.

5. The precision forming process for an automotive braking system air chamber according to claim 1, characterized in that, The edge trimming process includes the following steps: S401. Cool the lower shell final forging billet to below 150°C, and place the lower shell final forging billet in the edge trimming device; S402. The lower shell final forging billet is trimmed using a second press at a shearing speed of 10 mm / s, with a flash thickness of <0.5 mm and a blank edge burr of ≤0.05 mm. The second press is a 400t mechanical press.

6. The precision forming process for an automotive braking system air chamber according to claim 1, characterized in that, The temperature of the first heat treatment is 500-525℃, and the holding time is 1.5-2 hours; The second heat treatment includes the following steps: The upper shell final forging billet and the lower shell forging billet are solution treated at 530℃, held at the temperature for 3 hours, quenched with room temperature water, and held at 175℃ for 8 hours in an aging furnace to obtain the forging billet. The forging blank is subjected to water cooling, etching, pickling, and shot blasting processes to obtain a forging with work hardening and a smooth surface.

7. A forging apparatus for the precision forming process of an automotive braking system air chamber as described in any one of claims 1-6, characterized in that, This includes an integrated forging device for pre-forging and final forging of irregularly shaped cavities, and a trimming device; The irregular cavity pre-forging and final forging integrated forging device is used to forge the upper upsetting billet; The trimming device includes an upper trimming base plate (201) and a lower trimming base plate (205). The upper trimming base plate (201) is fixed to the slider of the press, and the lower trimming base plate (205) is fixed to the worktable of the press. The upper trimming base plate (201) and the lower trimming base plate (205) are connected by a trimming guide post (207). The upper trimming base plate (201) slides above the lower trimming base plate (205) along the trimming guide post (207) under the drive of the press. A trimming die (204) is provided on the trimming bottom plate (205). The outer contour of the trimming die (204) is consistent with the outer contour of the product. The trimming die (204) is used for blanking the product. A trimming punch (202) is fixedly provided at the bottom of the trimming top plate (201). The shape of the trimming punch (202) is the same as the inner cavity of the product. The trimming punch (202) slides on the trimming punch (202) under the drive of the trimming top plate (201). The trimming punch (202) is used to transmit the force of the press to the product. The trimming punch (202) is provided with a trimming stripper plate (203) on its periphery. The trimming stripper plate (203) is provided with a cutter (210) at its bottom. The cutter (210) has a slanted blade structure with an inclination angle of 5°. During the pressing down process of the trimming punch (202), the trimming stripper plate (203) is used to position the product and press down the flash. The cutter (210) is used to cut the flash of the product.

8. The forging apparatus according to claim 7, characterized in that, A cutting guide sleeve (206) is provided between the cutting guide post (207), the upper cutting base plate (201), and the lower cutting base plate (205). The cutting guide sleeve (206) and the cutting guide post (207) are used to correct the position of the cutter (210) during the cutting process so that the cutting positions are the same.

9. The edge-cutting device according to claim 7, characterized in that, The trimming stripper plate (203) is slidably mounted on the periphery of the trimming punch (202). A plurality of spring bolts (208) are provided between the trimming stripper plate (203) and the trimming upper base plate (201). Under the connection of the spring bolts (208), the trimming stripper plate (203) can slide under the drive of the trimming upper base plate (201). A spring is provided on the spring bolt (208). The spring connects the trimming upper base plate (201) and the trimming stripper plate (203) together. When the spring drives the trimming stripper plate (203) to be pressed down to the lowest point, it rebounds.

10. The forging apparatus according to claim 9, characterized in that, A material-coordinating bolt (209) is also provided between the trimming stripper plate (203) and the trimming upper base plate (201). The material-coordinating bolt (209) is located between the spring bolts (208). The material-coordinating bolt (209) is used to support and slide guide the trimming stripper plate (203). At the same time, the material-coordinating bolt (209) is used to assist in the positioning of the trimming guide sleeve (206) and the trimming guide post (207).

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