An automobile brake master cylinder body extrusion casting forming device and a casting method thereof

Abstract

The application discloses an automobile brake master cylinder body extrusion casting forming device and a casting method thereof, and belongs to the technical field of extrusion casting equipment. The device comprises a base, a supporting rod, a top seat, a hydraulic cylinder, a moving frame, a liquid inlet pipe, and a mounting assembly and a cooling assembly. The mounting assembly adopts a spring rotary locking structure of a control rod matched with a clamping block, so that the mold is quickly disassembled without tools; the cooling assembly adopts a water-air composite cooling system composed of a water cooling pipe and a cooling fan. The casting method adopts hierarchical filling, two-stage progressive pressurization and water-air composite cooling cooperation, effectively improving the casting density and grain refinement effect. The application is suitable for high-quality extrusion casting production of various automobile brake master cylinders.

Description

Technical Field

[0001] This invention relates to the field of extrusion casting equipment technology, specifically to an extrusion casting forming device and method for automotive brake master cylinder blocks, which is particularly suitable for producing aluminum alloy master cylinder block blanks for automotive brake systems using extrusion casting technology. Background Technology

[0002] As a core pressure-bearing component in a vehicle's braking system, the internal casting density and overall mechanical strength of the brake master cylinder directly affect the reliability of the braking response. During operation, the brake master cylinder must withstand repeatedly changing hydraulic loads, placing high demands on the density, grain refinement, and dimensional accuracy of the casting. Extrusion casting, which applies continuous high pressure during the solidification of molten metal, effectively reduces internal shrinkage cavities and refines the grains, making it a commonly used forming method for mass-producing high-strength aluminum alloy brake master cylinder blanks.

[0003] Existing squeeze casting equipment has the following shortcomings in actual production applications: Firstly, the efficiency of mold assembly and disassembly is low. In actual processing workshops, when faced with orders for different models of brake master cylinders, frequent switching of molding dies is required. Conventional extrusion casting equipment often uses bolt arrays to fix the upper and lower dies to the pressure plate of the frame. When changing to different specifications of dies, operators need to manually disassemble and retighten multiple sets of fixing bolts one by one. This cumbersome tool disassembly process consumes a significant amount of downtime, reducing the continuity of production line processing. For a multi-variety, small-batch production model, the proportion of equipment idle time caused by frequent mold changes increases significantly, directly affecting overall production efficiency.

[0004] Secondly, the reliability of bolt locking is insufficient. Extrusion molding processes involve cyclic high-pressure impact loads. Traditional bolt-locking structures are prone to thread tensile fatigue or stripping and loosening after long-term cyclic stress, leading to uneven stress on the mold fixing points. Once the bolts loosen, the mold is prone to displacement under high-pressure expansion forces, which can cause dimensional deviations in the casting or even fire hazards. Furthermore, the consistency of bolt preload is difficult to guarantee. Uneven stress on each bolt during manual tightening can cause gaps on the mold mating surfaces, affecting the molding quality of the casting.

[0005] Third, the mold closing and positioning accuracy is poor. Existing equipment lacks an independent anti-deflection guiding and positioning structure, relying on the operator's visual alignment of the edges during mold closing and fixing, resulting in poor assembly position accuracy. When the mold is subjected to the high-pressure expansion force of molten metal, it is prone to lateral slippage, causing the wall thickness of the main cylinder casting to exceed tolerances, reducing the finished product qualification rate. The uniformity of wall thickness in critical parts such as the piston hole and valve hole of the brake main cylinder directly affects its pressure-bearing performance and service life; excessive wall thickness deviation can lead to localized stress concentration, shortening the service life of the components.

[0006] Fourth, the heat exchange efficiency of the cooling system declines rapidly. During the extrusion casting process, the mold needs to withstand repeated thermal shocks from the high-temperature molten metal. Timely and effective cooling is crucial for controlling the solidification sequence of the casting and ensuring grain refinement. Existing equipment mostly uses single water cooling or air cooling methods, which have limited heat exchange efficiency. In some equipment equipped with air cooling, the dust filters are easily clogged by workshop dust after long-term use, resulting in increased airflow resistance and reduced air volume, which in turn leads to a gradual decline in heat dissipation efficiency. Moreover, the disassembly and cleaning of the filters often requires tools, making maintenance inconvenient. Operators are prone to neglecting daily inspections, further exacerbating the deterioration of cooling performance.

[0007] Fifth, the matching of casting process parameters is insufficient. Existing squeeze casting methods mostly use single-speed filling and constant pressure holding, which makes it difficult to balance filling stability and edge filling effect. The matching degree between the pressure loading method and the metal solidification stage is not high, which makes it easy for micro-shrinkage cavities to remain inside the casting. The density and mechanical properties are difficult to meet the requirements of high pressure-bearing components such as brake master cylinder.

[0008] Therefore, there is an urgent need to develop an extrusion casting molding device for automotive brake master cylinder that enables rapid mold assembly and disassembly, reliable locking, precise positioning, and convenient maintenance of the cooling system, along with a casting process method with optimized parameters, in order to solve the aforementioned problems in the existing technology. Summary of the Invention

[0009] This invention belongs to the technical field of extrusion casting equipment, specifically relating to an extrusion casting molding device and method for automotive brake master cylinder blocks. The technical problem this invention aims to solve is to address the problems existing in current extrusion casting equipment, such as cumbersome and time-consuming mold assembly and disassembly steps, poor locking reliability due to long-term pressure on traditional bolts, excessive wall thickness deviation in master cylinder block castings due to lack of positioning structure during mold closing, inconvenient maintenance of cooling system filters leading to reduced heat exchange efficiency, and low casting density due to insufficient matching of process parameters. This invention provides an extrusion casting molding device and method for automotive brake master cylinder blocks.

[0010] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: An extrusion casting apparatus for an automotive brake master cylinder includes a base, a support rod, a top seat, a hydraulic cylinder, a movable frame, and an inlet pipe; as well as a mounting assembly that connects the base and the movable frame.

[0011] The base serves as a load-bearing foundation support platform, bearing the operating weight and extrusion force of the entire equipment. The support rod is fixedly connected to the top of the base, and the top seat is fixedly connected to the top of the support rod. The hydraulic cylinder is fixedly connected to the inside of the top seat through a flange. The movable frame is fixedly connected to the output end of the hydraulic cylinder and slidably connected to the outer periphery of multiple support rods. The liquid inlet pipe is connected to and fixedly connected to the side wall of the movable frame, and is used to deliver the molten metal required for extrusion molding into the mold cavity.

[0012] The mounting assembly is used for tool-free disassembly, positioning, and locking of the mold, including a mold that snaps onto the opposing sidewalls of the movable frame and the base. The inner cavity of the mold shapes the outline of the main cylinder of the automotive brake. Both ends of the mold have sliding grooves, which are connected to locking slots. The sliding grooves and locking slots cooperate to provide internal accommodating space for the sliding insertion and rotational locking of the locking components.

[0013] Mounting rings are fixedly connected to the interior of both ends of the base and both ends of the movable frame. A control rod is slidably connected inside the mounting ring, and a limit block is fixedly connected to the outer periphery of the control rod. The limit block is slidably connected to the inner wall of the mounting ring, and the mounting ring provides spatial orientation constraint for the sliding and rotational movements of the control rod and the limit block. A locking block is fixedly connected to the end of the control rod, slidably connected to and engaged within a groove. A control lever is fixedly connected to the end of the control rod away from the locking block. The control lever receives pressing and torsional forces and transmits these forces to the control rod, causing it to synchronously displace and rotate.

[0014] A spring is fitted around the outer circumference of the control rod. The front end of the spring abuts against the inner wall of the mounting ring, and the rear end abuts against the end of the limiting block. When the spring is compressed, it accumulates elastic force, and the rebound tension pushes the limiting block and control rod to return to their original position, keeping the locking block firmly engaged inside the slot to prevent loosening. Pressing the control lever compresses the spring, causing the locking block to disengage from the slot and retract along the slide. This rotary locking mechanism, which eliminates the need to disassemble fasteners, replaces the traditional bolt-set fixing method, shortening the waiting time for changing and mounting multi-specification molds.

[0015] Furthermore, multiple positioning pins are fixedly connected to the opposing sidewalls of the movable frame and the base, and multiple positioning grooves matching the positioning pins are opened on the opposing sidewalls of the two molds. The positioning pins are engaged with the corresponding positioning grooves. During the mold closing and assembly stage, the cooperation between the positioning pins and the positioning grooves provides directional interference limiting, preventing lateral misalignment caused by pressure on the upper and lower molds, maintaining the uniformity of the cylinder blank wall thickness during extrusion casting, and reducing the probability of forming defects such as shrinkage porosity and blowholes.

[0016] Furthermore, a cooling assembly is connected to the side wall of the base. The cooling assembly includes a radiator fixedly connected to the side wall of the base, and a water-cooling pipe connected and fixedly connected to the end of the radiator. The water-cooling pipe is embedded inside the base and fits tightly against the mold. The contact and engagement between the water-cooling pipe and the mold shortens the heat transfer path and can quickly dissipate the heat accumulated in the mold.

[0017] Furthermore, the outer end of the radiator is fixedly connected to a mounting bracket, and two cooling fans are fixedly connected inside the mounting bracket by screws for forced air cooling to accelerate the dissipation of internal heat storage, forming a water-air composite cooling system that significantly improves the overall heat exchange efficiency.

[0018] Furthermore, a filter plate for blocking dust and impurities is slidably connected inside the mounting frame, and a handle is fixedly connected to the top of the filter plate. Two locking blocks are slidably connected inside the mounting frame; the ends of the locking blocks abut against the side walls of the filter plate, and sliding columns are fixedly connected to the ends of the locking blocks away from the filter plate. Springs are fitted around the outer circumference of the sliding columns; the front end of the springs abuts against the locking blocks, and the rear end abuts against the inner wall of the mounting frame. Handles are fixedly connected to the outer ends of the two sliding columns. Pulling the handles outwards unlocks and removes the filter plate for cleaning, reducing the difficulty of daily inspection and maintenance and preventing dust from clogging the air ducts and causing a decrease in heat exchange efficiency.

[0019] The present invention also provides a method for extrusion casting of an automotive brake master cylinder block, wherein the extrusion casting molding apparatus described above is used for casting, and the method includes the following steps: Step 1, Mold Installation: Press and rotate the control lever to compress the spring 1, aligning the locking block 1 with the slide groove. Push the preheated mold between the base and the moving frame. Release the control lever, and the spring 1 will spring back and push the locking block 1 into the slot to complete the locking. Step 2, Mold Closing and Alignment: Start the hydraulic cylinder to push the moving frame down along the support rod, and insert the positioning pin into the positioning slot to achieve precise alignment of the upper and lower molds until the parting surface is completely closed; Step 3, staged filling: Molten aluminum alloy at 720-750℃ is injected into the mold cavity through the inlet pipe. In the first stage, the filling speed is low at 0.15-0.2m / s to fill the cavity to 70-80% of the volume. In the second stage, the speed is increased to 0.25-0.3m / s to complete the remaining filling. Step 4, Two-stage pressure holding: Immediately after filling, apply a first-stage pressure of 40-60 MPa and hold for 5-8 seconds to complete the initial shrinkage. Then, increase the pressure to 60-90 MPa and hold for 7-17 seconds to allow the molten metal to solidify under progressive high pressure. Step 5, Water-Air Combined Cooling: While holding the pressure, the cooling components are turned on. The water-cooled pipes circulate coolant to directly remove the heat from the mold, and the cooling fan forces air cooling to accelerate the heat dissipation of the radiator, controlling the solidification of the casting from thick wall to thin wall. Step 6: Depressurize, open the mold, and remove the part: After the pressure holding is completed, slowly depressurize to normal pressure. The hydraulic cylinder drives the moving frame to move upward to open the mold. After pressing the control lever to unlock, remove the main cylinder casting of the brake.

[0020] Furthermore, the switching point of the staged filling is controlled at 75% of the cavity volume. The filling speed of the first stage is 0.18 m / s, and the filling speed of the second stage is 0.27 m / s. The entire filling process is completed within 8 to 12 seconds. The low-speed stage avoids splashing and air entrapment of molten metal, while the high-speed stage ensures complete filling of the cavity corners. The combination of the two-stage speeds significantly reduces the porosity of the casting.

[0021] Furthermore, the first-stage pressurization pressure is 50MPa and held for 6 seconds, and the second-stage pressurization pressure is 80MPa and held for 12 seconds, with a total holding time of 18 seconds. The first-stage pressure completes the volume compensation and initial compaction of the liquid metal, while the second-stage high pressure acts on the semi-solid metal to further refine the grains and eliminate micro-shrinkage pores. The two-stage progressive pressurization effectively improves the internal density of the casting.

[0022] Furthermore, the water inlet temperature of the water cooling pipe is controlled at 20-30℃, the cooling water flow rate is 15-25L / min, and the cooling fan speed is 1500-2500rpm; water cooling directly contacts the mold for rapid heat conduction, air cooling enhances the heat exchange efficiency of the radiator, and water-air composite cooling improves the cooling rate of the mold while ensuring a uniform temperature gradient to avoid thermal cracking in the casting.

[0023] Furthermore, the pressure relief time before mold opening shall not be less than 3 seconds, and the mold opening speed shall be controlled at 50-80 mm / s; the mold preheating temperature shall be 260-320℃, and the release agent spraying thickness shall be 0.1-0.2 mm; the method also includes a filter plate periodic maintenance step: pull the handle outward to unlock the second locking block, pull out the filter plate to clean the dust, and then insert it back to lock it, so as to maintain the long-term stable operation of the cooling system.

[0024] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention utilizes a spring-loaded locking structure within the mounting assembly, where a control lever engages with a locking block. Operators can control the locking block to slide back and forth within the groove and slot simply by pressing and rotating the control lever, eliminating the need for disassembling multiple sets of fasteners with auxiliary tools and shortening the disassembly and assembly time during mold changes for different main cylinder block sizes. Simultaneously, the spring-tensioned locking structure prevents bolts from loosening or stripping under prolonged high-pressure conditions, ensuring uniform and stable locking force and improving mold locking reliability during continuous production line processing.

[0025] 2. In the present invention, the positioning posts on the base and the moving frame cooperate with the positioning grooves on the side wall of the mold, providing directional interference limit during the mold clamping and assembly stage, preventing horizontal misalignment and offset of the upper and lower molds under pressure, maintaining uniform wall thickness of the cylinder blank during squeeze casting, reducing the probability of forming defects such as shrinkage porosity and air holes, ensuring that the pressure sealing performance of the automobile brake master cylinder meets the processing requirements, and improving the qualified rate of finished products.

[0026] 3. In the present invention, a composite cooling component with water-cooled pipes and cooling fans is arranged outside the base. The water-cooled pipes fit closely with the mold pipeline to circulate and dissipate high-temperature heat during the forming stage, and the external forced air cooling is matched to accelerate the heat dissipation rate. The water-air composite cooling system can dissipate the heat accumulated in the mold more efficiently, which is conducive to controlling the sequential solidification of castings and improving the grain refinement effect. The independent plug-pull filter plate cooperates with the lateral elastic clamping block structure, and the dust-proof net can be unlocked and drawn out by pulling outward, which reduces the difficulty of daily inspection and cleaning, effectively prevents the heat exchange efficiency from decreasing caused by workshop dust blocking the air duct, and ensures the long-term stable operation of the cooling system.

[0027] 4. The casting method matched with the present invention adopts a process scheme that combines graded filling, two-stage progressive pressing and water-air composite cooling: low-speed filling avoids air entrainment, high-speed filling ensures corner filling, first-stage pressure completes liquid feeding, second-stage high pressure refines grains to eliminate micro-shrinkage pores, and water-air composite cooling controls the solidification sequence. The parameter matching and optimization of the three processes can effectively control the solidification process of the brake master cylinder body casting, obtain high-quality castings with dense structure and fine grains, and the internal density can reach more than 99.5%, meeting the stringent requirements of core components of automobile brake systems on mechanical properties. Description of Drawings

[0028] Figure 1 is an overall perspective structural schematic diagram of the squeeze casting forming device for the automobile brake master cylinder body of the present invention; Figure 2 is a structural schematic diagram of the cooperation between the positioning post and the positioning groove of the present invention; Figure 3 is a sectional structural schematic diagram of the mounting assembly of the present invention; Figure 4 is a structural schematic diagram of the cooling component of the present invention; Figure 5 is a structural schematic diagram of the cooperation between the second clamping block and the second spring in the cooling component of the present invention.

[0029] In the diagram: 1. Base; 2. Support rod; 3. Top seat; 4. Hydraulic cylinder; 5. Moving frame; 6. Liquid inlet pipe; 7. Mounting assembly; 701. Mold; 702. Positioning pin; 703. Positioning groove; 704. Mounting ring; 705. Control rod; 706. Limit block; 707. Spring 1; 708. Locking block 1; 709. Slide groove; 710. Locking slot; 711. Control lever; 8. Cooling assembly; 801. Radiator; 802. Water cooling pipe; 803. Mounting frame; 804. Cooling fan; 805. Filter plate; 806. Locking block 2; 807. Sliding pin; 808. Spring 2; 809. Handle; 810. Handle. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Example

[0031] Please refer to Figures 1 to 5 This embodiment provides an extrusion casting molding apparatus for automotive brake master cylinder bodies, used for the extrusion casting molding production of aluminum alloy automotive brake master cylinder bodies.

[0032] like Figure 1 As shown, the device includes a base 1, which is welded from cast steel and serves as a load-bearing foundation platform to support the weight and extrusion pressure of the entire equipment. Four support rods 2 are fixedly connected to the four corners of the top of the base 1. The support rods 2 are made of high-strength alloy steel and have undergone surface hardening treatment to improve wear resistance. A top seat 3 is fixedly connected to the top of the support rods 2. A hydraulic cylinder 4 is fixedly connected inside the top seat 3 via a flange. The hydraulic cylinder 4 provides the driving force for the upper and lower mold opening and closing, as well as the pressure required for extrusion molding. A movable frame 5 is fixedly connected to the output end of the hydraulic cylinder 4. Guide sleeves are provided at the four corners of the movable frame 5, slidably connected to the outer periphery of the four support rods 2. The support rods 2 provide guidance and restriction for the upper and lower sliding trajectory of the movable frame 5, ensuring the straightness of the mold closing movement. A liquid inlet pipe 6 is connected and fixedly connected to the side wall of the movable frame 5. The liquid inlet pipe 6 is externally connected to a gating system for supplying molten aluminum alloy required for extrusion molding into the mold cavity.

[0033] The base 1 and the movable frame 5 are connected together by a mounting component 7, which is used for tool-free disassembly, positioning, and locking of the mold. Figure 3As shown, the mounting component 7 includes a mold 701, which is made of hot-work die steel and is snapped onto the opposing sidewalls of the movable frame 5 and the base 1. The inner cavity shape of the mold 701 matches the outer contour of the main cylinder of the automotive brake. Slide grooves 709 are provided at both ends of the mold 701, extending horizontally inward along the sidewalls of the mold. A locking groove 710 is connected to the end of each slide groove 709, which is circumferentially deflected at a certain angle relative to the slide groove 709, forming an L-shaped locking channel. The slide groove 709 and the locking groove 710 cooperate to provide internal space for the sliding insertion and rotational locking of the locking component.

[0034] Mounting rings 704 are fixedly connected to the interior of both ends of the base 1 and the interior of both ends of the movable frame 5. The mounting rings 704 are cylindrical structures with internal steps. A control rod 705 is slidably connected inside the mounting rings 704. A limit block 706 is fixedly connected to the outer periphery of the control rod 705. The limit block 706 is a disc-shaped structure and is slidably connected to the inner wall of the mounting rings 704. The mounting rings 704 provide spatial orientation constraints for the sliding and rotational movements of the control rod 705 and the limit block 706. A locking block 708 is fixedly connected to the end of the control rod 705 facing the mold. The locking block 708 is a protruding structure with a cross-sectional dimension that matches the slide groove 709. It can be slidably connected inside the slide groove 709 and can be locked inside the slot 710 after rotation. A control lever 705 is fixedly connected to the outer end of the lever away from the locking block 708. The control lever 711 is a flat knob-shaped lever, which is convenient for the operator to press and twist. The control lever 711 receives the pressing and twisting force and transmits the force to the control lever 705 so that it can synchronously generate axial displacement and circumferential rotation.

[0035] A spring 707, a cylindrical helical compression spring, is fitted around the outer periphery of the control lever 705. The front end of the spring 707 abuts against the inner stepped surface of the mounting ring 704, and the rear end abuts against the end of the limiting block 706. When the spring 707 is compressed, it accumulates elastic force, and the rebound tension pushes the limiting block 706 and the control lever 705 to return to their original position outwards, keeping the locking block 708 firmly engaged inside the slot 710, thus preventing loosening. When the mold needs to be disassembled, the operator presses the control lever 711 inwards to compress the spring 707, causing the locking block 708 to disengage from the slot 710. Rotating the control lever 711 aligns the locking block 708 with the slide groove 709, allowing the mold 701 to be pulled outwards. This rotating locking mechanism, which eliminates the need to disassemble fasteners, replaces the traditional bolt-set fixing method. The assembly and disassembly time for a single mold can be reduced from 15-20 minutes to 2-3 minutes, significantly shortening the waiting time for changing and mounting multi-specification molds 701.

[0036] like Figure 2As shown, to address the issue of lateral offset that easily occurs when traditional mold positioning relies on edge alignment, multiple positioning posts 702 are fixedly connected to the opposing sidewalls of the moving frame 5 and the base 1. The positioning posts 702 have a cylindrical structure with an inlet cone at the end. Multiple positioning grooves 703, which are cylindrical blind holes, are provided on the opposing sidewalls of the two molds 701, matching the positioning posts 702. During mold closing, the positioning posts 702 engage with the corresponding positioning grooves 703, providing a structural interference limit to prevent lateral deflection during mold closing. The fitting accuracy between the positioning posts and the positioning grooves can reach H7 / g6, effectively ensuring the alignment accuracy of the upper and lower molds, preventing lateral slippage of the molds during extrusion, and maintaining uniform casting wall thickness.

[0037] like Figure 1 and Figure 4 As shown, a cooling assembly 8 is connected to the side wall of the base 1. The cooling assembly 8 is used to accelerate heat dissipation from the mold and control the solidification process of the casting. The cooling assembly 8 includes a cooling radiator 801 fixedly connected to the side wall of the base 1, and a water-cooling pipe 802 connected and fixedly connected to the end of the cooling radiator 801. The water-cooling pipe 802 is made of copper tubing, embedded inside the base 1, and maintains a tight fit with the bottom surface of the mold 701. The contact and fit between the water-cooling pipe 802 and the mold 701 shortens the heat transfer path and can quickly conduct away the heat accumulated in the mold. The cooling radiator 801 is a finned tube heat exchanger with circulating cooling water inside, and heat dissipation is achieved through external air convection.

[0038] A mounting bracket 803 is fixedly connected to the outer end of the radiator 801. The mounting bracket 803 is formed by bending sheet metal. Two cooling fans 804 are fixedly connected to the inside of the mounting bracket 803 by screws. The cooling fans 804 are axial flow fans used for forced air cooling to accelerate the dissipation of heat stored inside the radiator 801. The contact water cooling of the water cooling pipe 802, combined with the forced air cooling of the cooling fans 804, forms a water-air composite cooling system. Compared with a single cooling method, the heat exchange efficiency is improved by more than 30%, which can more effectively control the mold temperature.

[0039] like Figure 4 and Figure 5 As shown, a filter plate 805 is slidably connected inside the air inlet side of the mounting bracket 803. The filter plate 805 is a detachable dust filter used to block dust and impurities in the workshop from entering the air duct. A handle 810 is fixedly connected to the top of the filter plate 805, and the top edge of the filter plate 805 is engaged in the bottom groove of the handle 810. A locking block 806 is slidably connected to each of the left and right sides inside the mounting bracket 803. The inner end of the locking block 806 is inclined and abuts against the side wall of the filter plate 805, providing a lateral locking effect. A sliding post 807 is fixedly connected to the outer end of the locking block 806 away from the filter plate 805, and the sliding post 807 extends outward through the side wall of the mounting bracket 803.

[0040] A second spring 808 is fitted around the outer periphery of the sliding column 807. The second spring 808 is a cylindrical helical compression spring. The front end of the second spring 808 abuts against the outer end face of the second locking block 806, and the rear end of the second spring 808 abuts against the inner wall of the mounting bracket 803. A handle 809, which is a U-shaped rod structure, is fixedly connected to the outer ends of the two sliding columns 807. When cleaning the filter plate 805, the operator pulls the handle 809 outward, causing the two sliding columns 807 to move outward simultaneously, compressing the second spring 808, causing the second locking block 806 to disengage from the side wall of the filter plate 805. The handle 810 can then be pulled upward to remove the filter plate 805 for cleaning. After cleaning, the filter plate 805 is inserted back into the mounting bracket 803, the handle 809 is released, and the second spring 808 rebounds, pushing the second locking block 806 to re-lock the filter plate 805. This tool-free, quick-release structure reduces the difficulty of daily inspection and cleaning, and can effectively prevent dust from clogging the air ducts in the workshop, thus preventing a decrease in heat exchange efficiency. Example

[0041] This embodiment provides a method for extrusion casting of an automotive brake master cylinder block, using the extrusion casting molding apparatus described in Embodiment 1 for casting production, specifically including the following steps: Step 1, Mold Installation: First, clean the cavity of mold 701, using compressed air to blow away residual aluminum shavings and oxide scale. Evenly spray a high-temperature resistant water-based release agent onto the inner wall of the cavity, controlling the spray thickness to 0.1–0.2 mm. Place the mold in a heating furnace and preheat to 280°C, maintaining this temperature for 2 hours to ensure uniform mold temperature. Then, press and rotate the control lever 711 on the equipment, causing the control rod 705 to compress the spring 707 inwards, aligning the locking block 708 with the entrance position of the slide groove 709. Push the preheated mold 701 horizontally into the mounting position between the base 1 and the moving frame 5. After confirming the mold is in place, release the control lever 711. The spring 707 rebounds, pushing the limit block 706 and the control rod 705 outwards to reset. The locking block 708 slides along the slide groove 709 and rotates under the spring force, locking into the slot 710, completing the locking and fixing of mold 701. Install and fix the upper and lower molds in the same manner.

[0042] Step 2, Mold Closure and Alignment: Start hydraulic cylinder 4. The piston rod extends, pushing the moving frame 5 smoothly downwards along the four support rods 2. During the descent, the positioning pin 702 at the bottom of the moving frame 5 first inserts into the positioning groove 703 at the top of the upper mold, and the positioning pin 702 on the base 1 inserts into the positioning groove 703 at the bottom of the lower mold. Precise alignment of the upper and lower molds is achieved through the precise cooperation of the positioning pins and grooves. The hydraulic cylinder continues to advance until the parting surfaces of the upper and lower molds 701 are completely aligned. Once the mold closing force reaches the set value, the mold remains closed.

[0043] Step 3, Staged Filling: Molten aluminum alloy is injected into the mold cavity through the gating system connected to the inlet pipe 6. The aluminum alloy used is ADC12, and the pouring temperature is controlled at 735℃. The filling process is divided into two stages: In the first stage, the filling speed is increased to 0.18 m / s until 75% of the cavity volume is reached. During this stage, the molten metal rises steadily, avoiding splashing and air entrapment, effectively reducing porosity defects in the casting. In the second stage, the speed is increased to 0.27 m / s to complete the filling of the remaining 25% of the cavity, ensuring that the molten metal fills the flanges, valve holes, and other corners at the solidification front, preventing incomplete filling defects. The entire filling process is completed within 8–12 seconds. The reasonable matching of the two-stage filling speed reduces the overall porosity of the casting by more than 40% compared to filling at a single speed.

[0044] Step 4, Two-Stage Pressurization and Holding: After filling, hydraulic cylinder 4 continues to apply pressure to extrude the molten metal within the mold cavity. The extrusion and holding process consists of two progressive pressurization stages: the first stage applies 50 MPa for 6 seconds, during which the metal remains in a relatively fluid liquid state, and the pressure facilitates the main volumetric shrinkage and initial compaction; the second stage increases the pressure to 80 MPa for 12 seconds, at which point the metal has entered a semi-solid state. Under this high pressure, the dendrite gaps are further compressed, refining the grain structure and eliminating internal micro-shrinkage cavities and porosity defects. The total holding time is 18 seconds, allowing the molten metal to fully solidify and form under progressive high pressure. This precise matching of the two pressure stages with the solidification phases ensures that the internal density of the casting reaches over 99.5%.

[0045] Step 5, Water-Air Composite Cooling: Simultaneously with the pressure holding start-up, the cooling component 8 is activated. Circulating cooling water flows through the water-cooling pipe 802, with the inlet water temperature controlled at 25℃ and a flow rate of 20L / min. The cooling water circulates within the water-cooling pipe, directly carrying away the heat accumulated in the mold through close contact with the bottom surface. Simultaneously, two cooling fans 804 are activated, with their speed set to 2000rpm, forcing air convection to accelerate heat dissipation from the radiator 801. The direct heat conduction of water cooling combined with the enhanced heat exchange of air cooling forms a water-air composite cooling system, increasing the overall cooling rate of the mold by more than 30% compared to a single cooling method. During the cooling process, controlling the solidification of the casting from thick-walled to thin-walled sections facilitates feeding and grain refinement, while the uniform temperature gradient prevents hot cracks in the casting.

[0046] Step Six: Depressurization, Mold Opening, and Part Removal: After the pressure holding period, slowly depressurize for at least 3 seconds. Once the cavity pressure has stabilized and dropped to atmospheric pressure, activate hydraulic cylinder 4 to move the moving frame 5 upwards to open the mold. Control the mold opening speed at 60mm / s to prevent thermal cracking of the casting due to rapid mold opening. After the mold is in place, press control lever 711 to unlock block 708. Use a special tool to remove the formed brake main cylinder casting, remove any remaining material from the gate, and after visual inspection and dimensional testing, proceed to the next process.

[0047] In addition, regular maintenance of the filter plates is performed during production: After each shift, pull outwards handle 809, causing sliding column 807 to compress spring 808, disengaging locking block 806 from filter plate 805. Pull upwards handle 810 to remove filter plate 805, and use compressed air to blow away dust and impurities adsorbed on the filter screen. After cleaning, insert filter plate 805 back into mounting bracket 803, release handle 809, and spring 808 pushes locking block 806 to relock filter plate 805. Regular maintenance ensures unobstructed airflow and maintains long-term stable heat exchange efficiency of the cooling system.

[0048] The automotive brake master cylinder casting produced using the apparatus and method of this embodiment has an internal density of over 99.5%, a tensile strength of ≥320MPa, an elongation of ≥3%, and a wall thickness deviation controlled within ±0.1mm. All performance indicators meet the technical requirements for automotive brake system master cylinders. The mold changeover time is reduced by more than 80% compared to traditional bolt fixing methods, effectively improving equipment uptime for multi-variety production.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A compression casting device for a car brake master cylinder, used for compression casting a car brake master cylinder, comprising a base (1), wherein a support rod (2) is fixedly connected to the top of the base (1); a top seat (3), fixedly connected to the top of the support rod (2), wherein a hydraulic cylinder (4) is fixedly connected to the inside of the top seat (3) via a flange; a movable frame (5), fixedly connected to the output end of the hydraulic cylinder (4), wherein the movable frame (5) is slidably connected to the outer periphery of a plurality of the support rods (2); and an inlet pipe (6), communicating with and fixedly connected to the side wall of the movable frame (5); characterized in that, The device further includes a mounting assembly (7) that is connected to both the base (1) and the movable frame (5), the mounting assembly (7) comprising: The mold (701) is snapped onto the opposite sidewalls of the movable frame (5) and the base (1). Both ends of the mold (701) are provided with sliding grooves (709), and the sliding grooves (709) are connected to the slots (710). Mounting rings (704) are fixedly connected to the inside of both ends of the base (1) and the inside of both ends of the movable frame (5); A control lever (705) is slidably connected to the inside of the mounting ring (704). A limit block (706) is fixedly connected to the outer periphery of the control lever (705). The limit block (706) is slidably connected to the inner wall of the mounting ring (704). A locking block (708) is fixedly connected to the end of the control lever (705). The locking block (708) is slidably connected to the inside of the slide groove (709) and locked into the inside of the slot (710). A control lever (711) is fixedly connected to the end of the control lever (705) away from the locking block (708). Spring 1 (707) is sleeved on the outer periphery of the control rod (705). The front end of spring 1 (707) abuts against the inner wall of the mounting ring (704), and the rear end of spring 1 (707) abuts against the end of the limiting block (706).

2. The extrusion casting apparatus for the main cylinder of an automotive brake according to claim 1, characterized in that, Multiple positioning posts (702) are fixedly connected to the opposing sidewalls of the movable frame (5) and the base (1). Multiple positioning grooves (703) matching the positioning posts (702) are opened on the opposing sidewalls of the two molds (701). The positioning posts (702) are engaged in the corresponding positioning grooves (703).

3. The extrusion casting apparatus for the main cylinder of an automotive brake according to claim 1, characterized in that, The side wall of the base (1) is connected to a cooling assembly (8). The cooling assembly (8) includes a radiator (801) fixedly connected to the side wall of the base (1) and a water cooling pipe (802) connected to and fixedly connected to the end of the radiator (801). The water cooling pipe (802) is embedded in the interior of the base (1) and fits against the mold (701).

4. The extrusion casting apparatus for the main cylinder of an automotive brake according to claim 3, characterized in that, The outer end of the radiator (801) is fixedly connected to a mounting bracket (803), and two cooling fans (804) are fixedly connected inside the mounting bracket (803) by screws.

5. The extrusion casting apparatus for the main cylinder of an automotive brake according to claim 4, characterized in that, The mounting bracket (803) has a filter plate (805) slidably connected inside. The top of the filter plate (805) is fixedly connected to a handle (810). The mounting bracket (803) has two locking blocks (806) slidably connected inside. The ends of the locking blocks (806) abut against the side wall of the filter plate (805). The ends of the locking blocks (806) away from the filter plate (805) are fixedly connected to sliding columns (807). The outer periphery of the sliding columns (807) is fitted with springs (808). The outer ends of the two sliding columns (807) are fixedly connected to handles (809).

6. A method for extruding and casting the master cylinder block of an automotive brake, characterized in that, Casting is performed using the extrusion casting apparatus according to any one of claims 1 to 5, the method comprising the following steps: Step 1: Mold Installation Press and rotate the control lever (711) to drive the control lever (705) to compress the spring (707), so that the locking block (708) is aligned with the slide groove (709). Push the preheated mold (701) between the base (1) and the moving frame (5), release the control lever (711), and the spring (707) will rebound and push the locking block (708) into the slot (710) to complete the locking. Step 2: Mold closing and alignment: Start the hydraulic cylinder (4) to push the moving frame (5) down along the support rod (2), and insert the positioning column (702) into the positioning groove (703) to achieve precise alignment of the upper and lower molds until the parting surface is completely closed; Step 3, tiered filling: Molten aluminum alloy at 720-750°C is injected into the mold cavity through the inlet pipe (6). In the first stage, the mold is filled at a low speed of 0.15-0.2 m / s to 70-80% of the cavity volume. In the second stage, the speed is increased to 0.25-0.3 m / s to complete the remaining filling. Step 4: Two-stage pressurization and pressure holding: After filling, apply a first-level pressure of 40-60 MPa and hold for 5-8 seconds to complete the initial feeding. Then, increase the pressure to 60-90 MPa and hold for 7-17 seconds to allow the molten metal to solidify under progressive high pressure. Step 5: Water-air combined cooling: While holding pressure and starting, the cooling component (8) is turned on. The water cooling pipe (802) circulates the coolant and directly removes the heat from the mold. The heat dissipation fan (804) forces air cooling to accelerate the heat dissipation of the radiator (801) and controls the casting to solidify sequentially from thick wall to thin wall. Step Six: Depressurize, open the mold, and remove the parts: After the pressure holding is completed, the pressure is slowly released to normal pressure. The hydraulic cylinder (4) drives the moving frame (5) to move upward to open the mold. After pressing the control lever (711) to unlock, the main cylinder casting of the brake is taken out.

7. The method for extruding and casting the master cylinder block of an automotive brake according to claim 6, characterized in that, In step three, the switching point of the staged filling is controlled at 75% of the cavity volume. The filling speed of the first stage is 0.18 m / s, and the filling speed of the second stage is 0.27 m / s. The entire filling process is completed within 8 to 12 seconds. The low-speed stage avoids splashing and air entrapment of molten metal, while the high-speed stage ensures complete filling of the cavity corners. The combination of the two-stage speeds reduces the porosity of the casting by more than 40%.

8. The method for extruding and casting the master cylinder block of an automotive brake according to claim 6, characterized in that, In step four, the first-stage pressurization pressure is 50 MPa and held for 6 seconds, and the second-stage pressurization pressure is 80 MPa and held for 12 seconds, for a total holding time of 18 seconds. The first-stage pressure completes the volume shrinkage and initial compaction of the liquid metal, while the second-stage high pressure acts on the semi-solid metal to further refine the grains and eliminate micro-shrinkage pores. The two-stage progressive pressurization makes the internal density of the casting reach more than 99.5%.

9. The method for extruding and casting the master cylinder block of an automotive brake according to claim 6, characterized in that, In step five, the water inlet temperature of the water cooling pipe is controlled at 20-30℃, the cooling water flow rate is 15-25L / min, and the cooling fan speed is 1500-2500rpm. Water cooling directly contacts the mold for rapid heat conduction, air cooling enhances the heat exchange efficiency of the radiator, and the water-air composite cooling increases the mold cooling rate by 30% while ensuring a uniform temperature gradient and preventing thermal cracks in the casting.

10. The method for extruding and casting the main cylinder block of an automotive brake according to claim 6, characterized in that, In step six, the pressure relief time before mold opening shall not be less than 3 seconds, and the mold opening speed shall be controlled at 50-80 mm / s; the mold preheating temperature shall be 260-320℃, and the release agent spraying thickness shall be 0.1-0.2 mm; the method also includes a filter plate periodic maintenance step: pull the handle (809) outward to unlock the second card block (806), pull out the filter plate (805), clean the dust, and then insert it back to lock it, so as to maintain the long-term stable operation of the cooling system.

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