A locking device for local pressure application in counter-gravity casting and counter-gravity casting equipment

Abstract

The present invention discloses a locking device for local pressurization of anti-gravity casting and an anti-gravity casting device, comprising a side mold locking part and an upper mold locking part, wherein the side mold locking part is fixed to the side mold template or frame of the anti-gravity casting device through a connecting component, and comprises a locking drive mechanism, a locking force transmission mechanism and a side mold locking block, wherein the locking force drive mechanism is provided with a locking force transmission mechanism, and the locking force transmission mechanism is connected to the side mold locking block, wherein the side mold locking block has an inclined surface, and the upper mold locking part is provided with an inclined surface adapted to the shape of the side mold locking block. When the present invention is applied to a multi-liter liquid pipe anti-gravity wheel casting molding device with a local pressurization device, a stable locking force can be provided during local pressurization, thereby significantly improving safety.

Description

Technical Field

[0001] The invention relates to the technical field of casting, in particular to a locking device for local pressurization of counter-gravity casting and counter-gravity casting equipment. Background Art

[0002] Lightweighting is one of the most important ways to save energy and reduce emissions for fuel vehicles and to reduce consumption and increase range for new energy vehicles. Replacing traditional steel materials with lightweight materials such as aluminum alloys has become an inevitable choice for the renewal of automobile design. Aluminum alloys used in automobiles can be divided into cast aluminum alloys and deformed aluminum alloys. Cast aluminum alloys are mainly used to manufacture components such as engines, clutch housings, wheels, and chassis parts. With the demand for improved casting quality and the development of casting technology, more parts are produced by low-pressure casting, differential pressure casting, and pressure-regulated casting, all of which belong to anti-gravity casting methods. The basic principle of this type of casting is to use low-pressure gas to drive the molten metal in the crucible or holding furnace, so that it rises through the riser and enters the mold cavity. After the filling is completed, the molten metal in the mold completes solidification and shrinkage compensation under pressure.

[0003] Traditional aluminum alloy low-pressure, differential pressure and pressure-regulated wheel casting technology usually adopts a single-gate single-riser tube filling technology. Taking aluminum alloy wheels as an example, a riser tube is set at the center of the wheel, that is, the wheel center position of the wheel, so that the metal melt enters the mold cavity and completes the filling and solidification. This method is simple in design and easy to implement, but the disadvantages are that the filling distance is long and the molding is difficult. In order to avoid cold shut, the temperature of the wheel metal mold is generally as high as 400°C or above, resulting in a low cooling rate of the wheel, coarse structure, and easy formation of shrinkage cavities and shrinkage in the hot joints. Casting defects such as shrinkage cavities and shrinkage are easy to form. In order to refine the structure and eliminate casting defects such as shrinkage cavities and shrinkage, water cooling, water mist cooling and other methods are generally used in the prior art to strengthen the cooling of the wheel mold. However, strengthening the cooling greatly shortens the solidification time of the wheel. For example, the solidification time of a large-size wheel after strengthening cooling can be shortened to less than 100s, but at the same time, it causes the problem of difficulty in controlling the temperature field of the wheel cooling and solidification process during the production process, resulting in difficulty in achieving sequential solidification, unstable product performance, and low pass rate.

[0004] There have been attempts at other filling methods in the prior art of wheels. Patent CN201010107026.8 discloses a low-pressure casting double-sided pouring process and device for aluminum alloy wheels. Gates are set on both sides of the wheel to allow molten aluminum to enter from the rim. By controlling the cooling, the molten aluminum crystallizes from the wheel center to the rim at the rapidly cooled mold temperature, shortening the distance the molten aluminum flows. Combined with cooling, shrinkage defects at the R angle or rim area are reduced. Patents CN201310557627.2, CN201410825962.0 and other documents disclose the use of a combination of a central gate and a gate on both sides in the hope of reducing the weight of the hub and improving the mechanical strength. CN201610390494.8 uses a one-machine dual-mold hub mold, and the gate is also set at the rim position to achieve one-time casting of two hubs.

[0005] However, the above-mentioned device and method also have obvious defects. For the method in which the aluminum liquid enters only from the rim, the inlet is set in the middle of the rim, which will cause diversion after entering, that is, filling the wheel center and the wheel rim at the same time, resulting in uncontrollable filling time at each location, and then uncontrollable solidification sequence, which is easy to form shrinkage defects. For the method of combining the central gate and the gate on both sides, since the aluminum liquid enters from two inlets, it will form a convergence in the middle position, which is easy to cause cold shut due to reasons such as poor gas discharge.

[0006] The applicant has designed a rapid sequential solidification wheel forming device and method based on a multi-liter liquid pipe, and the gate of the mold is set just below the wheel rim or outside the upper R angle of the lower wheel rim. This method can significantly reduce the filling distance and solve the problem of long-distance shrinkage compensation for large-sized wheels. At the same time, local mechanical pressurization is used to eliminate shrinkage cavities and shrinkage at the center of the wheel. However, since the pressure of local mechanical pressurization is very high, far exceeding the holding pressure of low-pressure or differential pressure casting, how to achieve effective mold locking to ensure the local pressurization effect during local mechanical pressurization has become an urgent problem to be solved. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a locking device for local pressurization of counter-gravity casting and a counter-gravity casting equipment.

[0008] The complete technical solution of the present invention includes:

[0009] A locking device for counter-gravity casting, the locking device for counter-gravity casting comprising a side mold locking part, an upper mold locking part and a lower mold locking part, the side mold locking part is fixed to the side mold template or frame of the counter-gravity casting equipment through a connecting component, comprising a locking drive mechanism, a locking force transmission mechanism and a side mold locking block, the locking force drive mechanism is provided with a locking force transmission mechanism, the locking force transmission mechanism is connected to the side mold locking block, the side mold locking block has an inclined surface, and the upper mold locking part and the lower mold locking part are provided with inclined surfaces adapted to the shape of the side mold locking block.

[0010] The locking drive mechanism can drive the side mold locking part to move left and right.

[0011] In the mold locking state, the inclined surface of the side mold locking block matches and fits with the inclined surfaces of the upper mold locking part and the lower mold locking part, and the side mold driving mechanism applies a locking force to the fitting surface.

[0012] In the mold locking state, the inclined surface of the side mold locking block is located above the inclined surfaces of the upper mold locking part and the lower mold locking part.

[0013] The locking drive mechanism is a hydraulic cylinder, and the locking force transmission mechanism is a hydraulic rod.

[0014] Anti-gravity casting equipment with the device.

[0015] The counter-gravity casting equipment is a low-pressure casting equipment or a differential pressure casting equipment.

[0016] The counter-gravity casting device further comprises a local pressurizing and refining device, wherein the local pressurizing and refining device comprises a local pressurizing mechanism and a refining mechanism;

[0017] The local pressure mechanism is arranged below the position corresponding to the wheel center of the anti-gravity casting wheel mold, and includes a pressure driving mechanism, a pressure transmission mechanism and a pressure applying mechanism. The pressure applying mechanism contacts the metal melt and applies pressure to the metal melt after the filling is completed.

[0018] The refinement mechanism is arranged on the anti-gravity casting wheel mold, corresponding to the position above the wheel center, and refines the metal melt during its solidification process.

[0019] The pressure driving mechanism is a hydraulic cylinder, the pressure transmitting mechanism is a hydraulic rod, and the pressure applying mechanism is a pressure block.

[0020] The thinning mechanism is an ultrasonic thinning mechanism or a vibration thinning mechanism.

[0021] The counter-gravity casting equipment comprises a mold, and a gate on the mold is opened on a circular surface just below the wheel rim.

[0022] The advantages of the present invention over the prior art are:

[0023] The applicant proposed a rapid sequential solidification wheel forming device and method based on multiple riser tubes, in which the gate of the mold is set directly below the rim of the wheel. By filling the mold with liquid in multiple riser tubes, the filling distance of the molten metal is shortened by more than half compared with the existing single riser tube mode, and the temperature of the metal mold can be reduced from the existing 420°C to below 320°C, which naturally speeds up the cooling speed and cooling effect of the wheel and realizes rapid sequential solidification. And further improved, a local pressurizing device is added at the center of the wheel, and the pressure applying mechanism contacts the molten metal and applies pressure to the molten metal after the filling is completed. The aluminum liquid here is solidified under extremely high pressure, eliminating the possibility of forming shrinkage cavities and shrinkage defects. However, since the pressure of local mechanical pressurization is very high, far exceeding the holding pressure of low-pressure or differential pressure casting, it brings safety hazards. Based on this, the applicant has designed a clamping device for local pressurization of anti-gravity casting. When applying local pressurization, the hydraulic cylinder applies clamping force to the fitting slope of the side mold locking block and the upper mold locking part, which can ensure that the metal melt can still maintain a good mold locking state under extremely high pressure conditions. When applied to a multi-liter liquid pipe anti-gravity wheel casting molding device with a local pressurization device, it can provide a stable clamping force during local pressurization, significantly improving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a schematic structural diagram of a wheel counter-gravity casting equipment structure with a mold locking device of the present invention in an unlocked state.

[0025] Figure 2 The present invention is a schematic structural diagram of a wheel counter-gravity casting equipment structure with a mold locking device of the present invention in a locked state.

[0026] Figure 3 It is a schematic diagram of a wheel structure in the prior art.

[0027] Figure 4 a is Figure 1 The part of the equipment that is prone to air entrainment when filling.

[0028] Figure 4 b is Figure 4 A partial enlarged view of a.

[0029] Figure 4 c is Figure 4 a Schematic diagram of the filling sequence during slow filling. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0031] like Figure 1As shown, the locking device of the present invention includes a side mold locking part, an upper mold locking part and a lower mold locking part, wherein the side mold locking part is fixed to the side mold template or frame of the counter-gravity casting equipment through a connecting part, including a first side mold locking part and a second side mold locking part, each side mold locking part includes a locking drive mechanism 11, a locking force transmission mechanism 12 and a side mold locking block 13, the locking force driving mechanism 11 can be a hydraulic cylinder, a motor or any other general driving mechanism in the prior art, and a hydraulic cylinder is preferably used here, and a locking force transmission mechanism is provided on the hydraulic cylinder. The locking force transmission mechanism preferably uses a hydraulic rod here, and the front end of the hydraulic rod is connected to the side mold locking block 13, and each side mold locking block is shaped like a semi-trapezoid, and has a forward-protruding inclined surface 14 at the front end, and the inclined surface 14 is used to respectively press the corresponding upper mold locking part inclined surface 16 on the upper mold locking part 15 and the corresponding lower mold locking part inclined surface on the lower mold locking part when locking the mold.

[0032] The locking drive mechanism 11 can drive the side mold locking part to move left and right to perform mold opening and mold locking operations.

[0033] In the mold locking state, the inclined surface of the side mold locking block matches and fits with the inclined surfaces of the upper and lower mold locking parts, and the side mold driving mechanism applies a certain clamping force to the fitting surface. In the mold locking state, the inclined surface of the side mold locking block is located above the inclined surfaces of the upper and lower mold locking parts.

[0034] When the upper, lower and side molds are clamped, Figure 1 As shown, the locking force driving mechanism 11 drives the side mold locking part to move outward to leave a mold closing space, and the upper mold template descends to close the mold. Then the locking force driving mechanism 11 drives the side mold locking part to move inward, so that the corresponding two inclined surfaces match and fit together. The inclined surface of the side mold locking block is located above the inclined surfaces of the upper and lower mold locking parts, and the mold is locked. Figure 2 As shown. Then proceed with the casting process. After completion, unlock by following the reverse sequence of the locking method.

[0035] After the present invention is locked, when the local pressurizing device locally pressurizes the aluminum liquid after filling, the pressure is transmitted to the upper mold through the aluminum liquid. At this time, the side mold driving mechanism applies a certain clamping force to the fitting surface of the upper mold locking part and the side mold locking part. The mold locking state under extremely high pressure can be ensured, which significantly improves safety.

[0036] The wheel forming device used in conjunction with the present invention and the supporting process are described below.

[0037] Figure 3This is a typical wheel structure diagram, in which in the prior art, the center of the wheel is usually called the wheel center, the part on the outside of the wheel that is assembled with the tire and supports the tire is called the rim, the wheel part that is installed and connected to the axle wheel center and supports the rim is called the spoke, and there is a window in the middle of the multiple spokes. The rim part that maintains and supports the direction of the tire is called the flange.

[0038] In the existing production of low-pressure or differential pressure cast aluminum alloy wheels, almost all of them use a riser pipe set at the central wheel center position of the wheel, and allow the melt to pass through the insulation cup and gate sleeve connected to the riser pipe, enter the mold cavity from the gate at the wheel center, and be diverted under the action of the diverter cone, and fill the mold in the order of wheel center-spoke-rim-rim, and solidify after filling the mold cavity. This is because in actual production, it is easiest to set the gate and riser pipe here, and the cross-sectional shape of the gate is a regular circle, which is simple to process. At the same time, the area of ​​the gate is large, which can make the filling speed fast. However, some problems caused by the above-mentioned pouring and filling method have never been well solved, such as the long gate distance, the long filling distance, and it is very difficult to compensate for shrinkage at the hot joints such as the connection between the rim and the spoke, which is easy to form shrinkage cavities and shrinkage, becoming a major problem that plagues the production of the wheel industry. Although water cooling, water mist cooling and other methods are used to enhance cooling in order to achieve sequential solidification, the short filling and solidification time of the wheel makes it difficult to accurately control the temperature field, and a considerable proportion of scrap is still inevitable.

[0039] In the prior art, bilateral pouring is performed at the middle of the rim side. However, the filling and solidification sequence is uncontrollable due to the filling diversion, which also easily leads to shrinkage defects.

[0040] Based on this problem, the present invention proposes a wheel forming device based on a multi-liter liquid channel, such as Figure 1 As shown, it includes a heat preservation furnace 1 containing aluminum liquid, a high-pressure gas source connected to the heat preservation furnace, and multiple riser pipes 2 are arranged in the heat preservation furnace, and the lower parts of the multiple riser pipes are immersed in the aluminum liquid 3. When the aluminum liquid in the furnace is pressurized by the high-pressure gas source, the aluminum liquid can rise along the multiple riser pipes. The riser pipe is connected to the gate of the mold through a thermos cup and the special-shaped gate assembly 4 disclosed in the present invention, and enters the mold cavity 5 of the mold. The special-shaped gate casting assembly includes a gate cup and a special-shaped gate sleeve located above it.

[0041] The gate of the mold is set on the annular surface directly below the wheel rim. It is particularly noted that the "annular surface directly below the wheel rim" in the present invention refers to the annular surface formed on the side of the rim opposite to the wheel flange, surrounding the center axis of the wheel. The outer circle of the annular surface is the circle formed by the outermost contour line of the wheel on the surface, and the inner circle is the circle formed by the outer contour line of the window area of ​​the wheel around the center axis of the wheel. Figure 3Correspondingly, the position where the sprue sleeve is connected to the mold is also arranged at this location.

[0042] Particularly preferably, the gate and the gate sleeve can be arranged at a position on the annular surface corresponding to the outer side of the window area, or can be arranged at a position on the annular surface corresponding to the connection between the rim and the spoke.

[0043] In a preferred embodiment, the gate can be provided with two, which can be symmetrically arranged on both sides of the wheel, or multiple gates can be arranged around the wheel axis. Corresponding to the gate, the riser can be provided with two, which can be symmetrically arranged on both sides of the wheel, or multiple riser can be arranged around the wheel axis.

[0044] The above device can significantly reduce the filling distance and solve the problem of long-distance shrinkage compensation for large-sized wheels. The filling and solidification time at the wheel center position is late, and the liquid flow convergence problem may occur, which may cause casting defects such as shrinkage cavities, shrinkage and inclusions. Therefore, a local pressurization and refinement device is added in this design, and the local pressurization and refinement device includes a local pressurization mechanism or / and a refinement mechanism; the local pressurization mechanism is arranged below the mold, corresponding to the position below the wheel center on the mold, including a pressure driving mechanism, a pressure transmission mechanism and a pressure applying mechanism, the pressure applying mechanism contacts the metal melt, and applies pressure to the metal melt after the filling is completed; the refinement mechanism is arranged above the wheel mold, corresponding to the position above the wheel center, and refines the metal melt during its solidification process. The pressure driving mechanism is a hydraulic cylinder 6, the pressure transmission mechanism is a hydraulic rod 7, and the pressure applying mechanism is a pressure block 8. The specific pressurization process is to apply a mechanical pressure of 1000KPa~120MPa after the filling is completed. The aluminum liquid here is solidified under extremely high pressure to prevent shrinkage defects from forming here due to insufficient edge shrinkage pressure.

[0045] The refinement mechanism is an ultrasonic refinement mechanism or a vibration refinement mechanism. In this specific embodiment, it includes a vibration generator 9 and a vibration rod 10. The vibration rod 10 is inserted into the aluminum liquid to vibrate the aluminum liquid during the solidification process, so that the dendrites formed by the aluminum liquid crystal are broken, the nucleation is enhanced, the grains are refined, and the mechanical properties of the wheel are improved.

[0046] The present invention also discloses a low-pressure / differential pressure casting process suitable for the filling mode. Since the pouring and filling method of the present invention has undergone tremendous changes compared with the prior art, the original filling method and solidification process cannot be applied to the present invention. Based on this, the present invention also designs a process suitable for the filling position.

[0047] The specific steps include:

[0048] (1) The locking drive mechanism drives the side mold locking part to move outward to leave a mold clamping space, and then the lower mold, the upper mold and the side mold are clamped. After the lower mold, the upper mold and the side mold are clamped, the locking drive mechanism drives the side mold locking part to move inward to make the two inclined surfaces match and fit together. The inclined surface of the side mold locking block is located above the inclined surface of the upper mold locking part, and the mold is locked;

[0049] (2) Liquor lifting: The aluminum liquid in the holding furnace is pressurized by a high-pressure gas source, so that the aluminum liquid rises to the pouring gate position along the liquid riser under pressure. The pressure raising speed in this stage is 2.8-4.0 KPa / s, and the pressure is increased to 20 KPa;

[0050] (3) Filling: Continue to increase the pressure to allow the aluminum liquid to enter the mold cavity through the gate. This filling stage is a two-stage pressurization. The pressure increase rate in the first stage is 0.1-0.2 KPa / s for 2-4 seconds. Then enter the second stage to increase the pressure rapidly until the mold cavity is filled. At this time, the pressure reaches 35 KPa.

[0051] The pressure increase speed P' of the second stage is determined as follows:

[0052]

[0053] Where:

[0054] P′ is the pressure increase rate, in kPa / s; H is the total height of the cavity, in mm; ρ is the density of the metal melt, in g / cm 3 ; K is the resistance coefficient, and its value range is 1 to 1.5; t is the preset filling time, in seconds, preferably 10 seconds; 102 is the unit conversion coefficient; N is the number of liquid riser tubes, and its value range is 2 to 6, which can be selected according to the number of windows of different types of wheels, preferably 2 to 4; x is its liquid rise index, and its value range is 0.2 to 0.8. In the wheel type scheme adopted in this embodiment, the value is 0.5.

[0055] (4) Crystallization pressurization and pressure holding: After filling is completed, the pressure is rapidly increased to 150 KPa at a pressure increase rate of 8 to 10 KPa / , and the pressure is maintained for 60 to 150 seconds. At this time, the wheel solidification is completed.

[0056] (5) Depressurization and venting: After the aluminum alloy wheel has solidified, the gas pressure in the holding furnace is released, allowing the unsolidified aluminum liquid in the riser and pouring nozzle to flow back into the holding furnace.

[0057] (6) Unlock the mold, eject the casting, and enter the next production cycle.

[0058] As for the selection of the pressure increasing speed in the liquid raising stage and the mold filling stage, since the inner diameter of the liquid raising pipe is fixed during the liquid raising, turbulence will basically not be generated, so a fast pressure increasing speed is adopted so that the metal melt can be quickly raised to the gate position and the liquid raising time is shortened. In the mold filling stage, the complex shapes of the mold cavity and the gate must be taken into consideration. In the traditional mold filling method, since the method of pouring from the wheel center position is adopted, the cross-sectional area of ​​the liquid raising pipe and the gate is not much different, and the cross-sectional area of ​​the mold cavity at the wheel center is large, and turbulence is not easy to be generated. Therefore, the filling pressure increasing speed can be obtained by experience or experiment. For the mold filling method of the present invention, the mold filling is carried out on the annular surface of the rim, which is an irregular conformal gate. The shape area of ​​the liquid raising pipe and the gate is very different. At the same time, the space at the rim is small. If the filling pressure is unreasonable, turbulent air is easily generated, resulting in pore defects. The filling pressure design in the prior art adopts the calculation method under the ideal state, combined with the resistance coefficient, etc. for correction. The flow state change caused by the change of the cross-sectional area of ​​the liquid raising pipe and the gate is not considered. Therefore, it is impossible to obtain the ideal filling and pressurizing speed by using the empirical formula in the prior art.

[0059] Therefore, the present invention has studied the above problems, combined with the riser, the gate, the shape and cross-sectional area of ​​the cavity above the gate, and the flow characteristics of the metal melt. It is found that for the wheel rim position, if Figure 4 In the circle indicated by the arrow in a, there are two parts where the area changes significantly in the initial stage of filling, such as Figure 4 At the circular frame indicated by the arrow in b, if turbulence occurs, air entrainment is very likely to form at this position. After design and calculation, the present invention adopts a two-stage pressurization. The first stage significantly reduces the pressurization speed so that the metal melt can flow smoothly in the initial stage of filling and fill the above area to avoid air entrainment. Figure 4 c (the arrow here indicates the direction of melt filling), and then enters the second stage of rapid pressure increase to shorten the filling time. In the second stage of the filling process of the present invention, it is found that the filling stability is significantly related to the number of riser tubes, because the traditional method of pouring from the wheel center position has only one riser tube and gate, so the law can be obtained through experiments and quantitative processing can be performed. In the filling method of the present invention, the number of riser tubes and gates can be 2 or more. Under the same boosting conditions, the flow rate at the gate and the flow rate in the cavity above the gate will change significantly, resulting in uncontrollable filling flow mode. Therefore, the present invention obtains the boosting method of the second stage through research. It can be seen from formula (1) that within the same preset filling time, as the number of riser tubes increases, the boosting speed that can be adopted can be gradually increased, and will not cause turbulent air entrainment and other problems. The value of the resistance coefficient is related to the viscosity of the molten metal, the complexity of the casting cavity, etc. When the resistance is small, the lower limit is taken, and when the resistance is large, the upper limit is taken.

[0060] Embodiment 1:

[0061] Two riser tubes and pouring gates are used, and the mass percentage composition of the metal melt is as follows: Si: 5-9%, Mg: 0.3-0.5%, Zr: 0.01-0.02%, B: 0.005-0.007%, RE: 0.002-0.005%, Nd: 0.002-0.005%, Fe: 0.05-0.15%, Mn: 0.05-0.1%, Ti: 0.08-0.14%, and the rest is Al and unavoidable impurities.

[0062] (1) The locking drive mechanism drives the side mold locking part to move outward to leave a mold clamping space, and then the lower mold, the upper mold and the side mold are clamped. After the lower mold, the upper mold and the side mold are clamped, the locking drive mechanism drives the side mold locking part to move inward to make the two inclined surfaces match and fit together. The inclined surface of the side mold locking block is located above the inclined surface of the upper mold locking part, and the mold is locked;

[0063] (2) Liquor lifting: The aluminum liquid in the holding furnace is pressurized by a high-pressure gas source, so that the aluminum liquid rises to the pouring gate position along the liquid riser under pressure. The pressure raising speed in this stage is 3.5 KPa / s, and the pressure is increased to 20 KPa;

[0064] (3) Filling: Continue to increase the pressure to allow the aluminum liquid to enter the mold cavity through the gate. The pressure increase rate in the first stage is 0.2 KPa / s and the time is 1.8 s, so that the metal melt is filled steadily. Figure 4 b The area indicated by the arrow enters the second stage and then quickly fills the mold at a pressure increase rate of 0.66 KPa / s until the cavity is filled.

[0065] (4) Crystallization pressurization and pressure holding: After the filling is completed, the pressure is quickly increased to 150KPa at a pressure increase rate of 8KPa / , and the pressure is maintained. The hydraulic cylinder drives the hydraulic rod to drive the pressure block to apply 2000KPa mechanical pressure to the wheel center position, and the vibration generator drives the vibration rod to vibrate and refine the aluminum liquid until the wheel solidifies. During the pressure holding process, the high pressure shrinkage of the rim hot section is always maintained at the gate. Under the high-pressure aluminum liquid shrinkage, the possibility of shrinkage cavities and shrinkage at this location is completely eliminated. At the same time, the pressure block locally pressurizes the metal liquid at the wheel center, eliminating the possibility of shrinkage cavities and shrinkage at this location.

[0066] (5) Depressurization and venting: After the aluminum alloy wheel has solidified, the gas pressure in the holding furnace is released, allowing the unsolidified aluminum liquid in the riser and pouring nozzle to flow back into the holding furnace.

[0067] (6) Unlock the mold, eject the casting, and enter the next production cycle.

[0068] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A counter-gravity casting device with a clamping device for counter-gravity casting, characterized in that: The locking device for counter-gravity casting comprises a side mold locking part, an upper mold locking part and a lower mold locking part, wherein the side mold locking part is fixed to the side mold template or the frame of the counter-gravity casting equipment through a connecting component, and comprises a locking driving mechanism, a locking force transmission mechanism and a side mold locking block, wherein the locking force driving mechanism is provided with a locking force transmission mechanism, the locking force transmission mechanism is connected to the side mold locking block, the side mold locking block is provided with an inclined surface, and the upper mold locking part and the lower mold locking part are provided with an inclined surface adapted to the shape of the side mold locking block; The counter-gravity casting equipment comprises a mold, wherein the gate on the mold is provided on a toroidal surface directly below the wheel rim; the toroidal surface directly below the wheel rim refers to a toroidal surface formed around the central axis of the wheel on the side of the rim opposite to the wheel flange; the outer circle constituting the toroidal surface is a circle formed by the outermost contour line of the wheel on the surface, and the inner circle is a circle formed by the outer contour line of the window area of ​​the wheel around the central axis of the wheel; The casting process of the counter-gravity casting equipment with the clamping device for counter-gravity casting is as follows: (1) The locking drive mechanism drives the side mold locking part to move outward to leave a mold clamping space, and then the lower mold, upper mold and side mold are clamped. After the lower mold, upper mold and side mold are clamped, the locking drive mechanism drives the side mold locking part to move inward to make the two inclined surfaces match and fit together. The inclined surface of the side mold locking block is located above the inclined surface of the upper mold locking part, and the mold is locked; (2) Liquid lifting: The aluminum liquid in the holding furnace is pressurized by a high-pressure gas source, so that the aluminum liquid rises to the pouring gate position along the liquid lifting pipe under pressure. The pressure raising speed in this stage is 2.8~4.0kPa / s, and the pressure is increased to 20kPa; (3) Filling: Continue to increase the pressure so that the aluminum liquid enters the cavity through the gate. This filling stage is a two-stage pressurization. The pressure increase rate in the first stage is 0.1~0.2kPa / s, and the time is 2~4s. Then enter the second stage of rapid pressure increase until the cavity is filled. At this time, the pressure reaches 35kPa; The boost speed of the second stage Determined by: （1） Where: is the pressure increase rate, in kPa / s; H is the total height of the cavity, in mm; is the density of the metal melt, in g / cm 3 ; is the resistance coefficient, and its value range is 1~1.5; is the preset filling time, in seconds; 102 is the unit conversion factor; N is the number of riser tubes, and its value range is 2~6; is its liquid rise index, ranging from 0.2 to 0.8; (4) Crystallization pressurization and pressure holding: After filling is completed, the pressure is rapidly increased to 150 kPa at a pressure increase rate of 8-10 kPa / , and the pressure is maintained for 60-150 seconds. At this time, the wheel solidification is completed; (5) Depressurization and venting: After the aluminum alloy wheel has solidified, the gas pressure in the holding furnace is released, allowing the unsolidified aluminum liquid in the riser and pouring gate to flow back into the holding furnace; (6) Unlock the mold, eject the casting, and enter the next production cycle.

2. The anti-gravity casting equipment according to claim 1, characterized in that: The locking drive mechanism can drive the side mold locking part to move left and right.

3. The anti-gravity casting equipment according to claim 2, characterized in that: In the mold locking state, the inclined surface of the side mold locking block matches and fits with the inclined surfaces of the upper mold locking part and the lower mold locking part, and the side mold driving mechanism applies a locking force to the fitting surface.

4. The anti-gravity casting equipment according to claim 3, characterized in that: In the mold locking state, the inclined surface of the side mold locking block is located above the inclined surfaces of the upper mold locking part and the lower mold locking part.

5. A counter-gravity casting device as claimed in claim 4, characterized in that: The counter-gravity casting equipment is a low-pressure casting equipment or a differential pressure casting equipment.

6. A counter-gravity casting device as claimed in claim 5, characterized in that: The counter-gravity casting device further comprises a local pressurizing and refining device, wherein the local pressurizing and refining device comprises a local pressurizing mechanism and a refining mechanism; The local pressure mechanism is arranged below the position corresponding to the wheel center of the anti-gravity casting wheel mold, and includes a pressure driving mechanism, a pressure transmission mechanism and a pressure applying mechanism. The pressure applying mechanism contacts the metal melt and applies pressure to the metal melt after the filling is completed. The refinement mechanism is arranged on the anti-gravity casting wheel mold, corresponding to the position above the wheel center, and refines the metal melt during its solidification process.

7. The anti-gravity casting equipment according to claim 6, characterized in that: The pressure driving mechanism is a hydraulic cylinder, the pressure transmitting mechanism is a hydraulic rod, and the pressure applying mechanism is a pressure block.

8. The anti-gravity casting equipment according to claim 7, characterized in that: The thinning mechanism is an ultrasonic thinning mechanism or a vibration thinning mechanism.

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