Die-casting die and die-casting method for forming auxiliary frame of automobile chassis

Abstract

The invention relates to the technical field of automobile auxiliary frame die-casting production, and provides a die-casting die and a die-casting method for forming an automobile chassis auxiliary frame, and the die-casting die comprises a movable die assembly, a fixed die assembly, a charging barrel, an exhaust block and a vacuum pump, and a first air exhaust part, a second air exhaust part and a third air exhaust part which are connected with a vacuum machine are respectively arranged on the charging barrel, the air exhaust block and the vacuum pump. Compared with the prior art, the method has the advantages that after filling of the product cavity is completed, the first vacuumizing state, the second vacuumizing state and the third vacuumizing state are conducted in sequence, the vacuum degree in the product cavity can be controlled to be 150 mbar or below 150 mbar, and therefore the die casting quality of the chassis auxiliary frame is improved, and the chassis auxiliary frame can meet the design requirement.

Description

Technical Field

[0001] The invention relates to the technical field of die-casting production of automobile subframes, in particular to a die-casting mold and a die-casting method for forming automobile chassis subframes. Background Art

[0002] The automobile chassis subframe is different from general die-casting parts. Its size reaches 507×858×215mm, its weight reaches 8.8kg, the maximum outer dimension of the mold body is ≥2.3m, the flatness of the mold frame parting surface is ≤0.1mm, the processing accuracy of the cavity forming part is ≤±0.1mm, and the processing accuracy of the cavity matching surface is ≤±0.03mm. In addition, the chassis subframe is a stress-bearing part, and its mechanical properties are much higher than those of ordinary die-casting products. The hardness of the die-casting parts is ≥75HRF, the elongation is ≥3.0%, the tensile strength is ≥200MPa, and the 0.2% elastic limit stress is ≥150MPa. For such large, high-precision and difficult die-casting molds, traditional die-casting technology cannot meet the product design requirements. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a die-casting mold and a die-casting method for forming an automobile chassis subframe in view of the current status of the prior art.

[0004] The technical solution adopted by the present invention to solve the above technical problems is: a die-casting mold for forming a chassis subframe of an automobile is provided, wherein the die-casting mold has at least a first vacuum state, a second vacuum state and a third vacuum state, and the die-casting mold comprises: Fixed mold assembly; A movable mold assembly, which is movably matched with the fixed mold assembly, and a product cavity is formed between the fixed mold assembly and the movable mold assembly; A barrel, which is inserted into the fixed mold assembly, the barrel is connected with the product cavity through a flow channel, and a pouring port and a first air extraction part are arranged at intervals along the feeding path on the barrel; An exhaust block is fixed between the movable mold assembly and the fixed mold assembly, the exhaust block is connected to the product cavity through an overflow groove, and a second exhaust portion is provided at one end of the exhaust block away from the overflow groove; A vacuum pump is fixed between the fixed mold assembly and the movable mold assembly and is connected to the product cavity through an overflow groove. A third air pumping part is provided at one end of the vacuum pump away from the product cavity. The first air pumping part, the second air pumping part and the third air pumping part are all connected to a vacuum machine. When the die-casting mold is in a first vacuum state, the vacuum machines connected to the first vacuum part, the second vacuum part and the third vacuum part are all in an open state; When the die-casting mold is in the second vacuum state, the vacuum machine connected to the first vacuum part is in a closed state, and the vacuum machines connected to the second vacuum part and the third vacuum part are both in an open state; When the die-casting mold is in the third vacuum state, the vacuum machines connected to the first vacuum part and the second vacuum part are in a closed state, and the vacuum machine connected to the third vacuum part is in an open state.

[0005] In the above-mentioned die-casting mold for forming an automobile chassis subframe, the vacuum pump comprises: A bottom plate connected to the movable mold assembly, wherein the bottom plate is provided with a connecting groove communicating with the overflow groove; An upper cover plate connected to the fixed mold assembly and movably abutting against the bottom plate; A pump body, which is connected inside the upper cover plate and movably pressed against the end surface of the bottom plate, a first through hole penetrating the pump body is provided inside the pump body, a second through hole communicating with the first through hole is provided on the side wall of the pump body, the first through hole is communicated with the connecting groove and a gas passage is formed between the connecting groove; The first oil cylinder is arranged on the fixed mold assembly, and the output shaft of the first oil cylinder is movably inserted in the first through hole. The output shaft of the first oil cylinder moves in the first through hole to control the opening and closing of the gas channel.

[0006] In the above-mentioned die-casting mold for molding an automobile chassis subframe, the barrel is in a hollow cylindrical shape, and the first air extraction portion is formed by a third through hole penetrating the wall thickness of the barrel.

[0007] In the above-mentioned die-casting mold for molding an automobile chassis subframe, filters are provided between the exhaust block and the vacuum machine and between the vacuum pump and the vacuum machine, and the filters are used to prevent the metal in the product cavity from entering the vacuum machine.

[0008] The above-mentioned die-casting mold for forming a chassis subframe of an automobile further includes at least two extrusion assemblies that move in sequence, each of which has: A second oil cylinder, which is arranged on the fixed mold assembly; A connector connected to an output end of the second oil cylinder; An extrusion sleeve connected to the fixed die assembly; A pressing block connected between the extrusion sleeve and the connecting head; An extrusion rod, one end of which passes through the pressing block and is connected to the connecting head, and the other end of which passes through the extrusion sleeve and is movably inserted in the product cavity.

[0009] The technical problem to be solved by the present invention further provides a die-casting method, including the above-mentioned die-casting mold, and the die-casting method comprises: S1, the die-casting machine closes the die-casting mold; S2, the metal raw material fills the product cavity through the barrel; S3, the die-casting mold enters the first vacuum state, the second vacuum state and the third vacuum state in sequence; S4, the die-casting machine pressurizes, maintains pressure, and cools the die-casting mold in sequence; S5. The die-casting machine opens the die-casting mold to obtain the automobile subframe.

[0010] The above-mentioned die-casting method comprises the steps of: S21, the die-casting machine punch is extended into the barrel to squeeze the metal raw material in the barrel into the product cavity.

[0011] In the above die-casting method, the steps include: S31, after the die-casting machine punch passes through the pouring port, the die-casting mold enters a first vacuum state; S32, after the die-casting machine punch passes through the exhaust hole, the die-casting mold enters the second vacuum state; S33, when the die-casting machine punch is switched from low-speed operation to high-speed operation, the die-casting mold enters a second vacuum state.

[0012] Compared with the prior art, the advantage of the present invention is that after the product cavity is filled, the first vacuum state, the second vacuum state and the third vacuum state are sequentially performed, so that the vacuum degree in the product cavity can be controlled at 150 mbar or below 150 mbar, thereby improving the die-casting quality of the chassis subframe so that it can meet the design requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a plan view of the die-casting mold of the present application when it is connected to the die-casting machine and is in a first vacuum state; Figure 2 is a plan view of the die-casting mold of the present application when it is connected to the die-casting machine and is in a second vacuum state; Figure 3 is a plan view of the die-casting mold of the present application when it is connected to the die-casting machine and is in a third vacuum state; Figure 4 It is a three-dimensional diagram of the fixed mold assembly; Figure 5 It is a three-dimensional diagram of the movable mold assembly; Figure 6 It is a three-dimensional diagram of a part of the structure of the present application; Figure 7 is a partial cross-sectional view of the vacuum valve; Figure 8It is a state diagram of the extruded component and the chassis subframe in the product cavity in the die casting mold; Fig. 9 is a perspective view of the extrusion assembly.

[0014] In the figure, 1. die-casting mold; 2. die-casting machine; 3. die-casting machine punch; 4. fixed mold assembly; 5. movable mold assembly; 6. barrel; 7. pouring port; 8. first exhaust section; 9. exhaust block; 10. overflow groove; 11. second exhaust section; 12. vacuum pump; 13. third exhaust section; 14. bottom plate; 15. connecting groove; 16. upper cover plate; 17. pump body; 18. first through hole; 19. second through hole; 20. first oil cylinder; 21. filter tip; 22. extrusion assembly; 23. second oil cylinder; 24. connector; 25. extrusion sleeve; 26. pressing block; 27. extrusion rod. DETAILED DESCRIPTION

[0015] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0016] A die-casting mold and die-casting method for forming a chassis subframe of an automobile, wherein the die-casting mold 1 has at least a first vacuum state, a second vacuum state and a third vacuum state, and the die-casting mold 1 comprises: a fixed mold assembly 4; a movable mold assembly 5, which is movably matched with the fixed mold assembly 4, and a product cavity is formed between the fixed mold assembly 4 and the movable mold assembly 5; a barrel 6, which is inserted into the fixed mold assembly 4, and the barrel 6 is connected to the product cavity through a flow channel, and a pouring port 7 and a first air pumping part 8 are arranged on the barrel 6 along the feeding path at intervals; an exhaust block 9, which is fixed between the movable mold assembly 5 and the fixed mold assembly 4, and the exhaust block 9 is connected to the product cavity through an overflow groove 10, and a second air pumping part 11 is arranged at one end of the exhaust block 9 away from the overflow groove 10; a vacuum pump 12, which is fixed between the fixed mold assembly 4 and the movable mold assembly 5 and It is connected to the product cavity through the overflow groove 10, and a third air pumping part 13 is provided at the end of the vacuum pump 12 away from the product cavity. The first air pumping part 8, the second air pumping part 11 and the third air pumping part 13 are all connected to the vacuum machine; when the die-casting mold 1 is in the first vacuum pumping state, the vacuum machines connected to the first air pumping part 8, the second air pumping part 11 and the third air pumping part 13 are all in the open state; when the die-casting mold 1 is in the second vacuum pumping state, the vacuum machine connected to the first air pumping part 8 is in the closed state, and the vacuum machines connected to the second air pumping part 11 and the third air pumping part 13 are in the open state; when the die-casting mold 1 is in the third vacuum pumping state, the vacuum machines connected to the first air pumping part 8 and the second air pumping part 11 are in the closed state, and the vacuum machine connected to the third air pumping part 13 is in the open state.

[0017] Based on the above embodiments, an exemplary structure of the present application is as follows: Figures 1 to 9As shown, in this scheme, the die-casting mold 1 has two product cavities, the discharge port 7 on the barrel 6 is used to receive the metal raw material from the die-casting machine 2, the first exhaust part 8 is connected to the vacuum machine through a pipeline (not shown in the figure), the flow channel is arranged between the movable mold component 5 and the fixed mold component 4, and there are six overflow grooves 10 between the movable mold component 5 and the fixed mold component 4, each product cavity is connected with three overflow grooves 10, and each corresponding product cavity is connected with two vacuum pumps 12 and an exhaust block 9, the overflow grooves 10 on both sides of the product cavity are connected to the vacuum pump 12, and the overflow groove 10 in the middle position is connected to the exhaust block 9. When working, the metal raw material first enters the die-casting mold through the discharge port 7 and fills the product cavity. After the product cavity is filled, the die-casting mold 1 is in a first vacuum state (such as Figure 1 As shown), the second vacuum state (as shown Figure 2 as shown) and the third vacuum state (as shown Figure 3 As shown in the figure, compared with the vacuuming operation before filling the product cavity in the prior art, in this solution, three states of vacuuming operations are performed after the product cavity is filled. Since the metal raw material occupies the volume in the product cavity and the gas in the product cavity is concentrated in one place after feeding, the vacuum machine in this solution can control the vacuum degree in the product cavity to 150 mbar or below 150 mbar, thereby improving the die-casting quality of the chassis subframe so that it can meet the design requirements.

[0018] Furthermore, the vacuum pump 12 includes: a base plate 14, which is connected to the movable mold assembly 5, and is provided with a connecting groove 15 connected to the overflow groove 10; an upper cover plate 16, which is connected to the fixed mold assembly 4 and movably abuts against the base plate 14; a pump body 17, which is connected in the upper cover plate 16 and movably abuts against the end surface of the base plate 14, and a first through hole 18 penetrating the pump body 17 is provided in the pump body 17, and a second through hole 19 connected to the first through hole 18 is provided on the side wall of the pump body 17, and the first through hole 18 is connected to the connecting groove 15 and a gas channel is formed between the connecting groove 15; a first oil cylinder 20, which is provided on the fixed mold assembly 4, and the output shaft of the first oil cylinder 20 is movably inserted in the first through hole 18, and the output shaft of the first oil cylinder 20 moves in the first through hole 18 to control the opening and closing of the gas channel.

[0019] The bottom plate 14 and the upper cover plate 16 are used to protect the pump body 17, so that the vacuum pump 12 can be used normally in the die-casting mold 1. After the third vacuum state of the die-casting mold 1 ends, the first oil cylinder 20 drives the output shaft to move to close the gas channel, so that the die-casting mold 1 can perform subsequent operations.

[0020] Preferably, the barrel 6 is in a hollow cylindrical shape, and the first air extraction portion 8 is formed by a third through hole penetrating through the wall thickness of the barrel 6 .

[0021] Furthermore, a filter 21 is provided between the exhaust block 9 and the vacuum machine and between the vacuum pump 12 and the vacuum machine. The filter 21 is used to prevent the metal in the product cavity from entering the vacuum machine.

[0022] During the die-casting process, aluminum slag and aluminum ash will be produced in the overflow groove 10. The filter tip 21 prevents these things from entering the vacuum machine through the pipe, thereby ensuring the normal operation of the vacuum machine. In addition, if equipment failure causes the metal raw material to run directly out of the product cavity from the overflow groove 10, the filter tip 21 can also prevent the metal raw material from flowing back into the vacuum machine.

[0023] Furthermore, it also includes at least two extrusion components 22 with sequential actions, each of which has: a second oil cylinder 23, which is arranged on the fixed mold component 4; a connecting head 24, which is connected to the output end of the second oil cylinder 23; an extrusion sleeve 25, which is connected to the fixed mold component 4; a pressing block 26, which is connected between the extrusion sleeve 25 and the connecting head 24; an extrusion rod 27, one end of which passes through the pressing block 26 and is connected to the connecting head 24, and the other end of the extrusion rod 27 passes through the extrusion sleeve 25 and is movably inserted in the product cavity.

[0024] Since the chassis subframe structure is too large, some areas are subjected to large forces, the internal structure is not dense, and there are defects such as pores during the molding process. Therefore, the present solution designs multiple extrusion components 22 at corresponding positions to extrude parts of the chassis subframe.

[0025] Specifically, eight local extrusion positions are set in the present scheme, and eight extrusion rods 27 are set correspondingly. After the feeding in the product cavity is completed, the second oil cylinder 23 drives the extrusion rod 27 to extrude the local structure of the chassis subframe through the connecting head 24, thereby solving the above-mentioned problem. Preferably, since the feeding and solidification times of the eight extrusion positions are different, the present scheme determines the starting time of the extrusion device according to the distance between each position and the barrel 6 and the CAE simulation results to check the solidification time of the metal raw material. One end of the extrusion rod 27 is movably inserted in the extrusion sleeve 25, which can provide a guiding effect for the movement of the extrusion rod 27 while increasing the extrusion pressure of the extrusion rod 27 on the chassis subframe, so that the extrusion rod 27 can be more easily inserted into the chassis subframe.

[0026] The present solution also provides a die-casting method, comprising the following steps: S1, the die-casting machine 2 closes the die-casting mold 1; S2, the metal raw material fills the product cavity through the barrel 6; S3, the die-casting mold 1 sequentially enters a first vacuum state, a second vacuum state, and a third vacuum state; S4, the die-casting machine 2 sequentially pressurizes, maintains pressure, and cools the die-casting mold 1; S5, the die-casting machine 2 opens the die-casting mold 1 to obtain an automobile subframe.

[0027] Further, the method includes step S21 , wherein the die-casting machine punch 3 extends into the barrel 6 to squeeze the metal raw material in the barrel 6 into the product cavity.

[0028] Further comprising step S31, after the die-casting machine punch 3 passes through the pouring port 7, the die-casting mold 1 enters a first vacuum state; S32, after the die-casting machine punch 3 passes through the exhaust hole, the die-casting mold 1 enters the second vacuum state; S33, when the die-casting machine punch 3 switches from low-speed operation to high-speed operation, the die-casting mold 1 enters a second vacuum state.

[0029] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0030] In addition, in the present invention, descriptions such as "first", "second", "one", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0031] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0033] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways without departing from the scope defined by the spirit of the present invention.

Claims

1. A die-casting mold for molding a chassis subframe of an automobile, the die-casting mold having at least a first vacuum state, a second vacuum state and a third vacuum state, characterized in that: The die-casting mold comprises: Fixed mold assembly; A movable mold assembly, which is movably matched with the fixed mold assembly, and a product cavity is formed between the fixed mold assembly and the movable mold assembly; A barrel, which is inserted into the fixed mold assembly, the barrel is connected with the product cavity through a flow channel, and a pouring port and a first air extraction part are arranged at intervals along the feeding path on the barrel; An exhaust block is fixed between the movable mold assembly and the fixed mold assembly, the exhaust block is connected to the product cavity through an overflow groove, and a second exhaust portion is provided at one end of the exhaust block away from the overflow groove; A vacuum pump is fixed between the fixed mold assembly and the movable mold assembly and is connected to the product cavity through an overflow groove. A third air pumping part is provided at one end of the vacuum pump away from the product cavity. The first air pumping part, the second air pumping part and the third air pumping part are all connected to a vacuum machine. When the die-casting mold is in a first vacuum state, the vacuum machines connected to the first vacuum part, the second vacuum part and the third vacuum part are all in an open state; When the die-casting mold is in the second vacuum state, the vacuum machine connected to the first vacuum part is in a closed state, and the vacuum machines connected to the second vacuum part and the third vacuum part are both in an open state; When the die-casting mold is in the third vacuum state, the vacuum machines connected to the first vacuum part and the second vacuum part are in a closed state, and the vacuum machine connected to the third vacuum part is in an open state.

2. A die-casting mold for molding an automobile chassis subframe as claimed in claim 1, characterized in that: The vacuum pump comprises: A bottom plate connected to the movable mold assembly, wherein the bottom plate is provided with a connecting groove communicating with the overflow groove; An upper cover plate connected to the fixed mold assembly and movably abutting against the bottom plate; A pump body, which is connected inside the upper cover plate and movably pressed against the end surface of the bottom plate, a first through hole penetrating the pump body is provided inside the pump body, a second through hole communicating with the first through hole is provided on the side wall of the pump body, the first through hole is communicated with the connecting groove and a gas passage is formed between the connecting groove; The first oil cylinder is arranged on the fixed mold assembly, and the output shaft of the first oil cylinder is movably inserted in the first through hole. The output shaft of the first oil cylinder moves in the first through hole to control the opening and closing of the gas channel.

3. A die-casting mold for molding an automobile chassis subframe as claimed in claim 1, characterized in that: The barrel is in a hollow cylindrical shape, and the first air extraction portion is formed by a third through hole penetrating through the wall thickness of the barrel.

4. A die-casting mold for molding an automobile chassis subframe as claimed in claim 1, characterized in that: A filter tip is provided between the exhaust block and the vacuum machine and between the vacuum pump and the vacuum machine. The filter tip is used to prevent the metal in the product cavity from entering the vacuum machine.

5. A die-casting mold for molding an automobile chassis subframe as claimed in claim 1, characterized in that: Also included are at least two extrusion assemblies with sequential actions, each of the extrusion assemblies having: A second oil cylinder, which is arranged on the fixed mold assembly; A connector connected to an output end of the second oil cylinder; An extrusion sleeve connected to the fixed die assembly; A pressing block connected between the extrusion sleeve and the connecting head; An extrusion rod, one end of which passes through the pressing block and is connected to the connecting head, and the other end of which passes through the extrusion sleeve and is movably inserted in the product cavity.

6. A die casting method, characterized in that A die-casting mold for forming an automobile chassis subframe as claimed in any one of claims 1 to 5, characterized in that the die-casting method comprises: S1, the die-casting machine closes the die-casting mold; S2, the metal raw material fills the product cavity through the barrel; S3, the die-casting mold enters the first vacuum state, the second vacuum state and the third vacuum state in sequence; S4, the die-casting machine pressurizes, maintains pressure, and cools the die-casting mold in sequence; S5. The die-casting machine opens the die-casting mold to obtain the automobile subframe.

7. A die casting method as claimed in claim 6, characterized in that: Includes steps: S21. The die-casting machine punch extends into the barrel to squeeze the metal raw material in the barrel into the product cavity.

8. A die casting method as claimed in claim 7, characterized in that: Includes steps: S31, after the die-casting machine punch passes through the pouring port, the die-casting mold enters the first vacuum state; S32, after the die-casting machine punch passes through the exhaust hole, the die-casting mold enters the second vacuum state; S33, when the die-casting machine punch is switched from low-speed operation to high-speed operation, the die-casting mold enters a second vacuum state.

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