Die casting equipment and process for automobile torque converter

Abstract

The invention discloses automobile torque converter die-casting equipment and technology, and belongs to the technical field of drawing equipment.The automobile torque converter die-casting equipment comprises a die-casting assembly, a clamping assembly and a detection assembly.The high-heat-conduction insert made of beryllium copper alloy is embedded in the corresponding wall thickness sudden change area in a movable die, and a water cooling channel led out from the back face is matched for continuous heat removal; the heat export rate of a hot spot area is greatly increased, the solidification time difference between a wall thickness sudden change area and a thin wall area is shortened, and a reasonable sequential solidification gradient is established; and after the hot spot area enters a semi-solidification state, the oil cylinder drives the extrusion pin to advance along the guide hole in the insert, volume loss generated by solidification shrinkage is forcibly compensated, the three parts are integrated at the corresponding position of the same hot spot, and the shrinkage cavity and shrinkage porosity defects of the wall thickness sudden change area are cooperatively eliminated from the three dimensions of material heat conduction, cooling layout and mechanical feeding.

Description

Technical Field

[0001] This invention relates to the field of drawing equipment technology, and in particular to a die-casting equipment and process for automotive torque converters. Background Technology

[0002] The torque converter is the core hydraulic component in an automatic transmission that transmits engine torque. During operation, its housing needs to withstand the centrifugal force generated by high-speed rotation and the pulsating pressure during the transmission of hydraulic torque. The requirements for the density and airtightness of the casting are extremely stringent. The torque converter housing is usually formed by aluminum alloy die casting process and is a typical thin-walled rotating body casting. The overall wall thickness is relatively thin, but there are obvious abrupt changes in wall thickness in the flange transition area, bushing hole wall and the root of the reinforcing rib due to functional and structural strength requirements.

[0003] However, the area of ​​abrupt change in wall thickness has a concentrated amount of metal, a large volume, and a relatively small heat dissipation area, i.e., a large modulus. After the die casting filling is completed, the cooling rate is much slower than that of the surrounding thin-walled area, forming a hot spot. The surrounding thin-walled area solidifies first to form a solid shell, which wraps around the thick-walled area in the middle, which is still in a liquid or semi-solid state. This cuts off the channel for the external liquid metal to replenish inward. The encased liquid metal continues to cool and shrink, but there is no new liquid metal to replenish it. In the end, internal defects such as shrinkage cavities or shrinkage porosity are formed at the abrupt change in wall thickness, which seriously affects the airtightness and mechanical properties of the shell under high-speed rotation and pulsating pressure conditions.

[0004] Existing technologies typically address these issues by increasing the cross-section of the ingate, raising the boost pressure, or adding cooling channels in the hot spot area. However, increasing the ingate only improves the hot spot closest to the gate. For complex annular shells like torque converter housings where hot spots are scattered in multiple locations, distant hot spots receive almost no benefit. Furthermore, increasing the gate size means more waste, increasing material costs and subsequent processing. While simply increasing the boost pressure can allow the molten metal in the entire cavity to withstand higher static pressure, the pressure must be transmitted through the liquid metal. If the thin-walled area between the gate and the hot spot solidifies first, blocking the pressure transmission channel, the external high pressure cannot reach the deeper hot spots. Excessive pressure can lead to a series of side effects, such as increased flash, shortened mold life, and bulging. While adding cooling channels in the hot spot area can shorten solidification time and reduce shrinkage tendency to some extent, the volume shrinkage accompanying the liquid-solid phase transformation of aluminum alloy is an inherent property of the material. As long as there is a sudden change in wall thickness, there will inevitably be a region that will solidify last. Simply relying on cooling methods can only reduce shrinkage from severe to mild, but cannot guarantee its complete elimination. There is still a lack of effective means to directly apply mechanical feeding to the hot spot location to address residual shrinkage tendency, making it difficult to meet the stringent requirements of torque converter housing for internal density and airtightness of the casting. Summary of the Invention

[0005] This invention provides a die-casting equipment and process for automotive torque converters, which can solve the problems in the prior art where insufficient thermal conductivity of mold steel leads to the formation of hot spots in areas of abrupt changes in wall thickness and the formation of shrinkage cavities and porosity due to solidification lag.

[0006] An automotive torque converter die-casting equipment includes: a die-casting assembly equipped with a cooling water circulation system, the die-casting assembly including a die-casting table, the die-casting table having a moving mold and a fixed mold, the moving mold and the fixed mold being used to form a cavity for the torque converter housing after mold closing and to complete the die-casting process; a clamping assembly for removing the die-cast part from the die-casting assembly and clamping it to a testing assembly; and a testing assembly including a testing housing and a support block, the testing housing and the support block being used to enclose the casting part and perform online testing on the casting part.

[0007] Preferably, a pair of fixed blocks are installed on the die-casting platform, one of which is equipped with a hydraulic cylinder. The output end of the hydraulic cylinder is connected to the moving mold, and the fixed mold is connected to the other fixed block.

[0008] Preferably, an insert mounting groove is provided in the moving mold at a position corresponding to the region of abrupt change in the wall thickness of the casting. A heat-conducting component is embedded in the insert mounting groove. The heat-conducting component includes a high-thermal-conductivity insert installed in the inner cavity of the moving mold. The front end face of the high-thermal-conductivity insert forms part of the cavity forming surface. The high-thermal-conductivity insert is made of beryllium copper alloy.

[0009] Preferably, the moving mold is provided with a water cooling channel, and the water cooling channel inlet and outlet are respectively led out from the back of the high thermal conductivity insert and connected to the cooling water circulation system of the die casting assembly.

[0010] Preferably, a hydraulic cylinder is installed on the outside of the moving mold, and an extrusion pin is installed at the output end of the hydraulic cylinder. A guide hole adapted to the extrusion pin is opened in the high thermal conductivity insert. The extrusion pin passes through the moving mold and the guide hole in sequence, and in the initial state, its front end face is flush with the front end face of the high thermal conductivity insert, together forming part of the cavity forming surface.

[0011] Preferably, an electric actuator is installed at one end of the support block, and a sealing gasket is embedded at one end of the detection housing and the support block that are close to each other.

[0012] Preferably, a water gap cavity is provided at the contact point between the detection housing and the support block, and the spacing between the water gap cavities is ~mm.

[0013] Preferably, the support block is equipped with a water injection and drainage system, which includes an inlet and an outlet communicating with the water gap cavity, for injecting deaerated water into the water gap cavity.

[0014] Preferably, an ultrasonic transducer assembly is installed inside the detection housing, the ultrasonic transducer assembly comprising a plurality of ultrasonic transducer elements, the ultrasonic transducer elements being embedded in the wall of the detection housing.

[0015] The die-casting process for the automotive torque converter includes the following steps: S1: The hydraulic cylinder drives the moving mold and the fixed mold to close the mold to form a cavity. The injection mechanism injects the aluminum alloy liquid into the cavity at high speed to complete the filling. During the filling process, the cooling water circulation system continuously introduces cooling water into the water cooling channel and accelerates the heat dissipation of the area with a sudden change in wall thickness through the high thermal conductivity insert. S2: After filling is completed, the injection mechanism switches to the pressure boosting and holding mode. After a preset delay time, the hydraulic cylinder drives the extrusion pin to advance into the cavity, applying local feeding pressure to the semi-solidified metal in the area of ​​sudden change in wall thickness, and maintaining the pressure until the metal in that area is completely solidified. S3: The extrusion pin retracts, the hydraulic cylinder drives the moving mold to retract to complete the mold opening, the ejection mechanism pushes the casting out of the moving mold, the clamping assembly picks up the casting and transfers it to the detection assembly; S4: The electric actuator drives the load block and the detection housing to close together and enclose the casting. The water injection and drainage system injects degassed water into the water gap cavity to form an ultrasonic coupling layer. The ultrasonic transducer group performs ultrasonic detection on the area of ​​sudden change in the wall thickness of the casting to obtain data on internal shrinkage cavities and porosity defects. S5: Determine whether the casting is qualified based on the ultrasonic test results. Qualified products enter the next process, while unqualified products are marked and rejected.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This solution uses a high thermal conductivity insert made of beryllium copper alloy to be embedded in the corresponding thickening change area in the moving mold. Combined with the water cooling channel led out from the back to continuously dissipate heat, the heat dissipation rate of the hot spot area is greatly improved compared with the H mold steel body. The solidification time difference between the thickening change area and the thin-walled area is significantly shortened, and the temperature difference on the mold surface is narrowed, which is conducive to establishing a reasonable sequential solidification gradient. After the high thermal conductivity insert controls the solidification process of the hot spot area to a semi-solidified state with an outer shell and the interior still having plasticity, the hydraulic cylinder drives the extrusion pin to advance along the guide hole in the insert. Local mechanical pressure is applied to the semi-solidified metal to force the volume loss caused by solidification shrinkage to be filled. The three are integrated at the same hot spot corresponding position. From the three dimensions of material thermal conductivity, cooling layout and mechanical shrinkage, the defect chain of heat concentration, solidification lag and insufficient shrinkage is cut off in a coordinated manner, eliminating the shrinkage and porosity defects in the thickening change area.

[0017] (2) This solution detects the closed cavity formed by the mating of the shell and the bearing block, and ensures the liquid tightness by the sealing gasket. The water injection and drainage system injects degassed water into the water gap cavity to form a continuous liquid coupling layer. The ultrasonic transducer group can complete signal transmission and reception without direct contact with the surface of the casting, realizing one-time full coverage scanning, so that die casting and internal defect detection can be completed on the same equipment, and unqualified castings can be found and removed in time within the production cycle. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the die-casting equipment provided by the present invention; Figure 2 This is a three-dimensional structural diagram of the die-casting component provided by the present invention; Figure 3 This is a schematic diagram of the moving mold and fixed mold structure provided by the present invention; Figure 4 This is a schematic diagram of the cross-sectional structure of the moving mold provided by the present invention; Figure 5 Provided by the present invention Figure 4 Schematic diagram of the structure at point A in the middle; Figure 6 This is a schematic diagram of the cross-sectional structure of the detection component provided by the present invention; Figure 7 Provided by the present invention Figure 6 A schematic diagram of the three-dimensional structure at point B.

[0019] Explanation of reference numerals in the attached figures: 1. Die-casting assembly; 2. Clamping assembly; 3. Detection assembly; 11. Die-casting table; 12. Fixing block; 13. Hydraulic cylinder; 14. Moving mold; 15. Fixed mold; 21. High thermal conductivity insert; 22. Water cooling channel; 23. Oil cylinder; 24. Extrusion pin; 31. Detection housing; 32. Bearing block; 33. Sealing gasket; 34. Water gap cavity; 35. Ultrasonic transducer assembly. Detailed Implementation

[0020] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0021] like Figure 1 , Figure 2 and Figure 4As shown in the figure, an embodiment of the present invention provides an automotive torque converter die-casting equipment, comprising: a die-casting assembly 1, on which a cooling water circulation system is installed, and the die-casting assembly 1 includes a die-casting table 11, on which a moving mold 14 and a fixed mold 15 are provided, the moving mold 14 and the fixed mold 15 are used to form the cavity of the torque converter housing after the mold is closed and to complete the die-casting molding; a clamping assembly 2, which is used to remove the die-cast part from the die-casting assembly 1 and clamp it to a detection assembly 3; and a detection assembly 3, which includes a detection housing 31 and a support block 32, which are used to enclose the casting part and perform online detection on the casting part.

[0022] like Figures 4 to 5 As shown, a pair of fixed blocks 12 are installed on the die-casting table 11. A hydraulic cylinder 13 is installed on one of the fixed blocks 12. The output end of the hydraulic cylinder 13 is connected to the moving mold 14, and the fixed mold 15 is connected to the other fixed block 12.

[0023] An insert mounting groove is provided in the moving mold 14 at the position corresponding to the region of abrupt change in the wall thickness of the casting. A heat-conducting component is embedded in the insert mounting groove. The heat-conducting component includes a high-thermal-conductivity insert 21 installed in the inner cavity of the moving mold 14. The front end face of the high-thermal-conductivity insert 21 constitutes part of the cavity forming surface. The high-thermal-conductivity insert 21 is made of beryllium copper alloy.

[0024] The moving mold 14 is provided with a water cooling channel 22. The water inlet and outlet of the water cooling channel 22 are respectively led out from the back of the high thermal conductivity insert 21 and connected to the cooling water circulation system of the die casting assembly 1.

[0025] A hydraulic cylinder 23 is installed on the outside of the moving mold 14. An extrusion pin 24 is installed at the output end of the hydraulic cylinder 23. A guide hole adapted to the extrusion pin 24 is opened in the high thermal conductivity insert 21. The extrusion pin 24 passes through the moving mold 14 and the guide hole in sequence. In the initial state, its front end face is flush with the front end face of the high thermal conductivity insert 21, and together they form part of the cavity forming surface.

[0026] Among them, the torque converter housing is a thin-walled rotating casting, and there are obvious abrupt changes in wall thickness in the flange transition area, bushing hole wall and the root of the reinforcing rib.

[0027] The total volume shrinkage rate of aluminum-silicon alloys commonly used in die casting is about 3.5% to 6% during the solidification process from liquid to solid. In areas with uniform wall thickness, the casting solidifies almost simultaneously in all parts, and the shrinkage is small and dispersed, so the problem is not prominent. However, in areas with abrupt changes in wall thickness, the metal content is concentrated, the volume is large, and the heat dissipation area is relatively small, that is, the modulus is large, and the cooling rate is much slower than in the surrounding thin-walled areas.

[0028] This leads to a key phenomenon: the surrounding thin-walled region solidifies first to form a solid shell, which wraps around the thick-walled region in the middle, which is still in a liquid or semi-solid state. This cuts off the channel for the external liquid metal to replenish itself. The encased liquid metal continues to cool and shrink, but there is no new liquid metal to replenish it. After solidification, it leaves shrinkage cavities or porosity inside. This isolated area that is finally solidified is the thermal point.

[0029] The region of abrupt change in the wall thickness of the torque converter housing is a typical hot spot location. Shrinkage defects and porosity severely affect the airtightness and mechanical properties of the housing under high-speed rotation and pulsating pressure conditions.

[0030] To address this, this solution involves locally embedding high thermal conductivity inserts 21 at locations corresponding to abrupt changes in wall thickness on the mold and configuring dedicated water-cooling channels 22 to selectively accelerate the solidification process in the hot spot region. Simultaneously, an extrusion pin 24 is placed at the same location to apply mechanical feeding when the metal is in a semi-solidified state. By enhancing the synergistic effect of heat dissipation and local extrusion, shrinkage cavities and porosity defects are eliminated. The specific method is as follows: A pair of fixed blocks 12 are installed on the die-casting table 11. A hydraulic cylinder 13 is installed on one of the fixed blocks 12. The output end of the hydraulic cylinder 13 is connected to the moving mold 14. The fixed mold 15 is fixedly installed on the other fixed block 12. The hydraulic cylinder 13 drives the moving mold 14 to move along the die-casting table 11 and close with the fixed mold 15 to form the cavity of the torque converter housing.

[0031] An insert mounting groove is provided inside the moving mold 14 at the location corresponding to the abrupt change in the casting wall thickness. A high thermal conductivity insert 21 made of beryllium copper alloy is embedded in the insert mounting groove, and the front end face of the high thermal conductivity insert 21 directly forms part of the cavity forming surface. After the aluminum liquid fills the cavity, the metal in the hot spot area is in close contact with the front end face of the high thermal conductivity insert 21. Since the thermal conductivity of beryllium copper alloy is about three to four times that of conventional hot work die steel, the heat at the hot spot is conducted to the interior through the high thermal conductivity insert 21 at a much higher rate than in other parts of the mold. The solidification process in this area is selectively accelerated, the duration window of the hot spot is compressed, and the area of ​​the final solidification region is reduced accordingly.

[0032] The moving mold 14 is provided with a water cooling channel 22. The water inlet and outlet of the water cooling channel 22 are led out from the back of the high thermal conductivity insert 21 and connected to the cooling water circulation system of the die casting assembly 1. The cooling water flows continuously on the back of the high thermal conductivity insert 21, and carries away the heat absorbed by the high thermal conductivity insert 21 from the cavity side in an instant. This forms a directional heat conduction path on the high thermal conductivity insert 21 with rapid heat absorption at the front end and continuous heat dissipation at the back end, so that the high thermal conductivity insert 21 always maintains a low initial temperature during continuous batch production, and can stably strengthen heat dissipation in the hot spot area in each mold.

[0033] It should be noted that accelerating heat dissipation can shorten the solidification time of the hot spot area and reduce the spatial range of the final solidification area. However, the volume shrinkage accompanying the liquid-solid phase transformation of aluminum alloy is an inherent property of the material. As long as there is a sudden change in wall thickness, there will inevitably be a final solidification area. Cooling methods can reduce the tendency of shrinkage cavities from severe to mild, but cannot guarantee that it will be completely eliminated. It is still necessary to use mechanical means to finally fill the remaining shrinkage cavities.

[0034] A hydraulic cylinder 23 is installed on the outside of the moving mold 14. The working pressure of the hydraulic cylinder 23 is 10-30 MPa. A pressing pin 24 is installed at its output end. The pressing pin 24 is a high-strength steel cylindrical pin with a diameter selected between 8 and 30 mm depending on the size of the hot spot area of ​​the casting. The material is SKD61H13 hot work die steel and is surface nitrided to improve wear resistance and resistance to aluminum liquid adhesion.

[0035] The high thermal conductivity insert 21 has a guide hole that matches the extrusion pin 24. The extrusion pin 24 passes through the moving mold 14 and the guide hole in sequence. In the initial state, its front end face is flush with the front end face of the high thermal conductivity insert 21. The two together form part of the cavity forming surface.

[0036] The key to eliminating shrinkage cavities and porosity defects by the extrusion pin 24 lies not in the fact that it can apply pressure, but in applying pressure at the correct time window. Timing control is the core of the entire mechanism, and its working process is divided into the following four stages according to the timing: The first stage is the filling period. The injection punch of the die-casting machine pushes the molten aluminum to fill the cavity at high speed. This process usually only takes tens of milliseconds. During this stage, the extrusion pin 24 remains in its initial position and its front end is normally covered by the molten aluminum as part of the cavity wall, without affecting the filling flow.

[0037] The second stage is the pressure boosting and holding period. After filling is completed, the injection mechanism switches to the pressure boosting and holding mode, and the molten metal in the entire cavity is subjected to a static high pressure of 30 to 90 MPa. At this time, the outer layer of the casting begins to solidify and form a shell, but the inside of the hot spot area is still in a liquid or pasty state. During this stage, the extrusion pin 24 has not yet moved and is in a waiting state.

[0038] The third stage is the action period of the extrusion pin 24, which is the key moment in the entire sequence. The timing starts from the end of filling and after a preset delay time, usually 1 to 5 seconds, depending on the casting wall thickness and alloy composition, the control system issues a command, and the hydraulic cylinder 23 drives the extrusion pin 24 to advance into the cavity along the guide hole. The advancing stroke is usually 5 to 15 mm.

[0039] The setting of this delay directly determines the effect of extrusion and feeding: if the delay is too short, the metal in the hot spot area will still be completely liquid. After the extrusion pin 24 is pushed in, it will only push the liquid metal to another place, and it will not be able to establish effective feeding pressure. It may even disrupt the flow field. If the delay is too long, the metal will have completely solidified into a rigid solid. If the extrusion pin 24 cannot be pushed in or is forcibly pushed in, it will cause the casting to crack.

[0040] The correct delay should allow the extrusion pin 24 to be pushed in when the metal in the hot spot region is in a semi-solidified state, corresponding to a solidification fraction of approximately 30% to 70%. The high thermal conductivity insert 21 controls the solidification process in the hot spot region at a predictable pace by accelerating heat dissipation, thus defining a stable and repeatable process window for the intervention of the extrusion pin 24.

[0041] The fourth stage is the pressure holding period until complete solidification. After the extrusion pin 24 is pushed into place, it does not immediately retract, but remains in the extended position to continue applying pressure until the metal in the hot spot area is completely solidified before retracting with the mold opening action.

[0042] After the front end of the extrusion pin 24 extends into the semi-solidified metal, its function of eliminating shrinkage cavities and porosity is reflected in three aspects. The first is forced volume compensation: the extrusion pin 24, as a rigid entity, is pushed in a certain distance, and the pushed-in volume directly replaces the voids originally caused by solidification shrinkage. This is equivalent to injecting additional volume from the outside at the hot spot to compensate for the shrinkage.

[0043] Taking a rough numerical calculation as an example, assuming the metal volume of a certain hot spot region is 10 cm³, and the solidification shrinkage rate is 5%, the volume that needs to be compensated for is 0.5 cm³. If a 12 mm diameter extrusion pin 24 is used, its cross-sectional area is about 1.13 cm², and the pushing distance is only about 4.4 mm to completely compensate for the shrinkage.

[0044] Secondly, pressure transmission densification: the pressure applied by the extrusion pin 24 is transmitted to the surroundings through the unsolidified liquid and semi-solid metal. According to Pascal's law, an increase in pressure at any point in a closed liquid will be transmitted equally to every part of the liquid. This high static pressure compresses existing micropores and shrinkage, causing them to close or significantly shrink. According to Boyle's law, if the pressure increases tenfold, the pore volume will shrink to one-tenth of its original size. On the other hand, it forces the residual liquid metal to penetrate into the microscopic gaps between dendrites to fill the shrinkage between dendrites and improve the density of the structure.

[0045] Thirdly, it bypasses the blockage of the feeding channel: Without the extrusion pin 24, the feeding of the hot section area can only rely on the pressure transmitted from the gate direction. However, the thin-walled area between the gate and the hot section has often solidified and blocked the pressure transmission channel, and the pressure at the far end cannot be delivered. The extrusion pin 24 is directly set at the hot section position, which is equivalent to establishing a local feeding source in the local area where feeding is most needed. It does not rely on the far-end pressure transmission channel and is not affected by the solidification and blockage of the gate.

[0046] The presence of the outer solidified shell simultaneously blocks the channel through which molten aluminum leaks in the reverse direction along the gap between the extrusion pin 24 and the guide hole, allowing the pressure output by the cylinder 23 to be effectively transmitted to the interior of the semi-solidified area without leakage.

[0047] Since the extrusion pin 24 has been pushed into the cavity in a semi-solid state, a circular pit with the same cross-sectional shape as the extrusion pin 24 will be left on the surface of the casting after the mold is opened and the part is removed. The depth of the pit is the pushing stroke of the extrusion pin 24.

[0048] Therefore, the arrangement of the extrusion pin 24 on the mold not only needs to meet the process requirement of spatial alignment with the hot spot area, but also needs to take into account the design constraints of whether the surface of the casting at this location allows for the presence of pits in terms of product function.

[0049] On the torque converter housing, the extrusion pin 24 is positioned within the machining allowance area of ​​the flange face. This area will be removed during subsequent finishing processes. The pit left by the extrusion pin 24 is removed along with the allowance material, and will not affect the flatness of the sealing surface, the assembly fit accuracy, or the appearance quality of the finished part.

[0050] The above solution uses a high thermal conductivity insert 21 in conjunction with a water cooling channel 22 and an extrusion pin 24 to eliminate shrinkage defects in the hot spot area, rather than relying solely on traditional methods such as increasing the gate size, increasing the boost pressure, or simply adding cooling. This is a targeted choice based on the structural characteristics of the torque converter housing itself.

[0051] If the traditional approach of increasing the gate size is adopted, the hope is to deliver more liquid metal to the hot spot area before solidification to complete the feeding process by using a shorter filling path and a larger flow cross section. However, the torque converter housing is a complex annular shell with hot spots scattered in multiple locations, each with different distances and directions from the gate. Increasing the gate size can only improve the one or two hot spots closest to the gate, and is almost powerless for the distant hot spots. Moreover, increasing the gate size means more waste, increasing material costs and subsequent processing volume.

[0052] If the injection system is increased to make the molten metal in the cavity bear higher static pressure to assist in shrinkage, the pressure must be transmitted through the molten metal. Once the channel between the gate and the hot spot solidifies and blocks, the external high pressure cannot be delivered. Furthermore, excessive pressure will lead to a series of side effects such as increased flash, shortened mold life, and mold expansion.

[0053] While relying solely on cooling methods such as the high thermal conductivity insert 21 and water-cooling channel 22 can shorten solidification time and reduce the degree of hot spot lag, thus mitigating the severity of shrinkage cavity tendency, the presence of a sudden change in wall thickness inevitably results in a final solidification zone. Cooling methods can only reduce the size of shrinkage cavities, not eliminate them completely. The unique advantage of the extrusion pin 24 lies in its direct physical intervention at the hot spot location. It does not rely on distant pressure transmission channels, is unaffected by gate solidification blockage, and directly applies feeding at the final solidification location, complementing the cooling methods.

[0054] Through the synergistic cooperation of the above structures, the high thermal conductivity insert 21 is responsible for establishing a thermal conductivity rate in the hot spot area that is much higher than that of the mold body to accelerate solidification and reduce the size of the hot spot. The water cooling channel 22 is responsible for maintaining the stability and repeatability of this thermal conductivity rate in each mold cycle during continuous production. Together, they regulate the solidification rhythm of the hot spot area to a semi-solidification window suitable for the intervention of the extrusion pin 24. The extrusion pin 24 then completely fills the volume loss caused by solidification shrinkage within this window through rigid volume replacement and high static pressure transmission.

[0055] The three components are structurally integrated at the same hot spot position of the moving mold 14, and functionally complement each other: the cooling method shortens the solidification time, reduces the size of the hot spot, and reduces the tendency of shrinkage cavity; the extrusion pin 24 completes the final elimination of the residual shrinkage cavity tendency. The two work together to form an integrated system of directional enhanced heat dissipation, continuous and stable heat dissipation, and precise extrusion and shrinkage compensation. From the three dimensions of material heat conduction, cooling layout, and mechanical shrinkage compensation, the defect generation chain of heat concentration, solidification lag, and insufficient shrinkage compensation is cut off simultaneously, thereby effectively eliminating shrinkage cavity and porosity defects in the torque converter housing wall thickness change area.

[0056] like Figures 6 to 7 As shown, an electric actuator is installed at one end of the bearing block 32, and a sealing gasket 33 is embedded at one end of the detection housing 31 and the bearing block 32 close to each other.

[0057] A water gap cavity 34 is provided at the contact point between the detection housing 31 and the bearing block 32, and the spacing of the water gap cavity 34 is 2 to 5 mm.

[0058] A water injection and drainage system is installed on the support block 32. The water injection and drainage system includes an inlet and an outlet that are connected to the water gap cavity 34, and is used to inject deaerated water into the water gap cavity 34.

[0059] An ultrasonic transducer assembly 35 is installed inside the detection housing 31. The ultrasonic transducer assembly 35 includes several ultrasonic transducer elements, which are embedded in the wall of the detection housing 31.

[0060] After the torque converter housing is die-cast, it is impossible to determine whether there are residual shrinkage cavities or porosity defects in the area where the wall thickness changes abruptly. Non-destructive testing is required for confirmation. However, the torque converter housing is a thin-walled part of rotation with curvature and varying wall thickness. Traditional contact ultrasonic testing requires the probe to be placed against the workpiece surface point by point and a coupling agent to be applied. For such complex curved castings, the operation efficiency is low and the coupling stability is poor, making it difficult to meet the online full inspection requirements under the die-casting production cycle.

[0061] Therefore, this solution uses water immersion coupling instead of traditional probe contact coupling. The casting is placed in a closed cavity that matches its outer contour. Degassed water is filled between the outer surface of the casting and the inner wall of the cavity to form a continuous liquid coupling layer. This allows the ultrasonic transducer element embedded in the cavity wall to complete signal transmission and reception without direct contact with the surface of the casting. The specific method is as follows: An electric actuator is installed at one end of the support block 32, which drives the support block 32 to move toward the detection housing 31.

[0062] After die casting is completed and the mold is opened and the casting is removed, the casting is taken out from the moving mold 14 by the clamping assembly 2 and transferred to the bearing block 32. The clamping assembly 2 includes a multi-axis robotic arm and a pneumatic gripper installed at its end. The robotic arm moves to one side of the moving mold 14 after the mold is opened according to a preset trajectory. After the pneumatic gripper picks up the casting, it is transported to the positioning surface of the bearing block 32 and released, thus completing the automatic transfer of the casting from the die casting station to the inspection station. The robotic arm drive, pneumatic gripper clamping and trajectory control of the clamping assembly 2 are all mature automated handling solutions in the existing technology, and will not be described in detail here.

[0063] After the casting is placed on the support block 32, it moves with the block and enters the detection housing 31. After the detection housing 31 and the support block 32 are aligned, the casting is completely enclosed in the closed space formed by the two.

[0064] A sealing gasket 33 is embedded at one end of the detection housing 31 and the bearing block 32 that are close to each other. After they are joined, the sealing gasket 33 is deformed by pressure and sticks tightly to the mating surface, preventing the subsequently injected liquid from leaking out from the mating gap, and providing a sealing guarantee for establishing a stable liquid coupling environment in the closed space.

[0065] A water gap cavity 34 is provided at the contact point between the detection housing 31 and the bearing block 32. The spacing of the water gap cavity 34 is 2 to 5 mm. This spacing allows a uniform and controllable thin liquid space to be maintained between the outer surface of the casting and the inner wall of the detection housing 31.

[0066] A water injection and drainage system is installed on the support block 32. The water injection and drainage system includes an inlet and an outlet that are connected to the water gap cavity 34. After the assembly is completed, degassed water is injected into the water gap cavity 34 through the inlet. The degassed water fills all the gaps between the outer surface of the casting and the inner wall of the detection housing 31, forming a continuous liquid coupling layer covering the entire surface of the casting to be inspected.

[0067] Degassed water, instead of ordinary water, is used as the coupling medium because the degassed treatment removes the tiny dissolved bubbles in the water, preventing bubbles from adhering to the surface of the casting or suspending in the water gap cavity 34 and causing scattering and attenuation of the ultrasonic wave propagation path, thus ensuring that the coupling layer transmits ultrasonic signals with uniformity and stability.

[0068] An ultrasonic transducer assembly 35 is installed inside the detection housing 31. The ultrasonic transducer assembly 35 includes several ultrasonic transducer elements. The ultrasonic transducer elements are embedded in the wall of the detection housing 31, and the arrangement of each transducer element corresponds to the area on the casting that needs to be inspected.

[0069] During testing, the ultrasonic transducer element excites ultrasonic waves, which pass through the wall of the testing housing 31 and enter the degassed water layer in the water gap cavity 34. Then, they are transmitted into the interior of the casting wall through the liquid coupling layer. When they encounter the interface of defects such as shrinkage cavities or shrinkage porosity, they are reflected. The reflected signal returns along the original path and is received by the transducer element. The location and size of the defects inside the casting can be determined based on the time and amplitude of the echo signal.

[0070] With the cooperation of the above structures, the detection housing 31 and the support block 32 are matched to form a closed cavity. The sealing gasket 33 ensures the liquid tightness of the cavity. The water gap cavity 34 establishes a liquid coupling channel with uniform thickness between the casting and the transducer. After the degassed water fills the channel, the ultrasonic wave can complete the signal coupling and transmission without the probe directly contacting the surface of the casting. The ultrasonic transducer group 35 is embedded in the wall of the detection housing 31 and arranged corresponding to each inspected area of ​​the casting to achieve a one-time full-coverage scan of the entire casting.

[0071] This detection method does not rely on point-to-point contact between the probe and the workpiece surface, and is not limited by the curved shape of the casting surface. It can complete the online non-destructive testing of shrinkage cavities and porosity defects inside the torque converter housing within the die-casting production cycle.

[0072] The die-casting process for automotive torque converters includes the following steps: S1: Hydraulic cylinder 13 drives moving mold 14 and fixed mold 15 to close the mold to form a cavity. The injection mechanism injects aluminum alloy liquid into the cavity at high speed to complete the filling. During the filling process, the cooling water circulation system continuously introduces cooling water into the water cooling channel 22 and accelerates the heat dissipation of the wall thickness change area through the high thermal conductivity insert 21. S2: After filling is completed, the injection mechanism switches to the pressure boosting and holding mode. After a preset delay time, the hydraulic cylinder 23 drives the extrusion pin 24 to advance into the cavity, applying local feeding pressure to the metal in the semi-solidified state in the area of ​​sudden change in wall thickness, and maintaining the pressure until the metal in that area is completely solidified. S3: Extrusion pin 24 retracts, hydraulic cylinder 13 drives moving mold 14 to retract to complete mold opening, ejection mechanism pushes casting out of moving mold 14, clamping assembly 2 clamps casting and transfers it to detection assembly 3; S4: The electric actuator drives the bearing block 32 and the detection housing 31 to close together and enclose the casting. The water injection and drainage system injects degassed water into the water gap cavity 34 to form an ultrasonic coupling layer. The ultrasonic transducer group 35 performs ultrasonic detection on the casting wall thickness abrupt area to obtain internal shrinkage cavity and porosity defect data. S5: Determine whether the casting is qualified based on the ultrasonic test results. Qualified products enter the next process, while unqualified products are marked and rejected.

[0073] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A die-casting equipment for automotive torque converters, characterized in that, include: The die casting assembly (1) is equipped with a cooling water circulation system and includes a die casting table (11). The die casting table (11) is provided with a moving mold (14) and a fixed mold (15). The moving mold (14) and the fixed mold (15) are used to form the cavity of the torque converter housing after the mold is closed and to complete the die casting process. Clamping assembly (2), the clamping assembly (2) is used to remove the die-casting completed casting from the die-casting assembly (1) and clamp it to the detection assembly (3); The detection component (3) includes a detection housing (31) and a support block (32), which are used to enclose the casting and perform online detection on the casting.

2. The automotive torque converter die-casting equipment as described in claim 1, characterized in that, A pair of fixed blocks (12) are installed on the die-casting table (11), one of the fixed blocks (12) is equipped with a hydraulic cylinder (13), the output end of the hydraulic cylinder (13) is connected to the moving mold (14), and the fixed mold (15) is connected to the other fixed block (12).

3. The automotive torque converter die-casting equipment as described in claim 1, characterized in that, The moving mold (14) has a slot for mounting a block at a position corresponding to the region of sudden change in the wall thickness of the casting. A heat-conducting component is embedded in the slot. The heat-conducting component includes a high-thermal-conductivity block (21) installed in the cavity of the moving mold (14). The front end face of the high-thermal-conductivity block (21) forms part of the cavity forming surface. The high-thermal-conductivity block (21) is made of beryllium copper alloy.

4. The automotive torque converter die-casting equipment as described in claim 3, characterized in that, The moving mold (14) is provided with a water cooling channel (22). The water inlet and outlet of the water cooling channel (22) are respectively led out from the back of the high thermal conductivity insert (21) and connected to the cooling water circulation system of the die casting assembly (1).

5. The automotive torque converter die-casting equipment as described in claim 3, characterized in that, A hydraulic cylinder (23) is installed on the outside of the moving mold (14). An extrusion pin (24) is installed at the output end of the hydraulic cylinder (23). A guide hole adapted to the extrusion pin (24) is opened in the high thermal conductivity insert (21). The extrusion pin (24) passes through the moving mold (14) and the guide hole in sequence. In the initial state, its front end face is flush with the front end face of the high thermal conductivity insert (21) and together they form part of the cavity forming surface.

6. The automotive torque converter die-casting equipment as described in claim 1, characterized in that, An electric actuator is installed at one end of the bearing block (32), and a sealing gasket (33) is embedded at one end of the detection housing (31) and the bearing block (32) close to each other.

7. The automotive torque converter die-casting equipment as described in claim 1, characterized in that, A water gap cavity (34) is provided at the contact point between the detection housing (31) and the support block (32), and the spacing between the water gap cavities (34) is 2 to 5 mm.

8. The automotive torque converter die-casting equipment as described in claim 7, characterized in that, The support block (32) is equipped with a water injection and drainage system, which includes an inlet and an outlet connected to the water gap cavity (34) for injecting deaerated water into the water gap cavity (34).

9. The automotive torque converter die-casting equipment as described in claim 1, characterized in that, An ultrasonic transducer assembly (35) is installed inside the detection housing (31). The ultrasonic transducer assembly (35) includes several ultrasonic transducer elements, which are embedded in the wall of the detection housing (31).

10. A die-casting process for an automotive torque converter, characterized in that, The automotive torque converter die-casting equipment includes any one of claims 1 to 9, wherein the automotive torque converter die-casting process includes the following steps: S1: The hydraulic cylinder (13) drives the moving mold (14) and the fixed mold (15) to close the mold and form a cavity. The injection mechanism injects the aluminum alloy liquid into the cavity at high speed to complete the filling. During the filling process, the cooling water circulation system continuously introduces cooling water into the water cooling channel (22) and accelerates the heat dissipation of the wall thickness change area through the high thermal conductivity insert (21). S2: After filling is completed, the injection mechanism switches to the pressure boosting and holding mode. After a preset delay time, the oil cylinder (23) drives the extrusion pin (24) to push into the cavity, apply local feeding pressure to the metal in the semi-solidified state in the area of ​​sudden change in wall thickness, and maintain the pressure until the metal in the area is completely solidified. S3: The extrusion pin (24) retracts, the hydraulic cylinder (13) drives the moving mold (14) to retract to complete the mold opening, the ejection mechanism pushes the casting out from the moving mold (14), the clamping assembly (2) clamps the casting and transfers it to the detection assembly (3). S4: The electric actuator drives the bearing block (32) and the detection housing (31) to close together and enclose the casting. The water injection and drainage system injects degassed water into the water gap cavity (34) to form an ultrasonic coupling layer. The ultrasonic transducer group (35) performs ultrasonic detection on the area of ​​sudden change in the wall thickness of the casting to obtain data on internal shrinkage cavities and porosity defects. S5: Determine whether the casting is qualified based on the ultrasonic test results. Qualified products enter the next process, while unqualified products are marked and rejected.

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