Quantitative feeding device for vacuum die-casting machine

Abstract

The utility model provides a quantitative feeding device for a vacuum die-casting machine and a feeding method of the quantitative feeding device, and belongs to the technical field of feeding devices. The feeding device comprises a vacuum exhaust system, a mold cavity, a melting cup, an alloy melt holding furnace and a punch. According to the feeding method, the principle of dynamic pressure difference and dynamic height difference is utilized, the quantitative weight is set, and precise aluminum alloy die-casting quantitative feeding is achieved in the mode that the pressure difference between the atmosphere and a mold cavity and / or melting cup vacuum and the liquid level height difference between the melting cup and an alloy melt heat preservation furnace are balanced. According to the utility model, the melting cup is communicated with the alloy solution holding furnace through the riser tube, the alloy solution in the melting cup is injected into the mold cavity through the punch, and the liquid suction process is the exhaust process, so that the filling rate can be improved or completely canceled, the quantitative feeding and vacuum exhaust efficiency is greatly improved, the feeding and injection time is shortened, and the production efficiency is improved. The defects caused by temperature drop of conventional alloy feeding are avoided, the production efficiency is improved, and the equipment cost is greatly reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of feeding devices, in particular to a quantitative feeding device for a vacuum die-casting machine. Background Art

[0002] The widely used aluminum alloy die-casting feeding methods are divided into air pressure metering, pump metering, and spoon metering. The first two items need to pass through the flow channel into the melting cup. In addition to the expensive equipment, it is restricted by the flow velocity and temperature drop of the flow channel, especially for large integrated body parts. The metering process is greatly restricted. The biggest problem with quantitative feeding through the spoon is the presence of surface aluminum oxide and inaccurate precision. Utility Model Content

[0003] In view of this, in order to solve the technical problems of expensive equipment and inaccurate precision in the prior art, the utility model provides a quantitative feeding device for a vacuum die-casting machine, which omits the existing pouring port, connects the melting cup with the alloy solution insulation furnace by using a liquid riser, vacuumizes the vacuum exhaust system, and uses a punch to press the alloy solution in the melting cup into the mold cavity, wherein the process of absorbing liquid is the process of exhausting, which can improve or completely eliminate the filling rate, greatly improve the efficiency of die-casting quantitative feeding and die-casting vacuum exhaust, shorten the feeding and injection time, avoid the defects caused by the temperature drop of conventional aluminum alloy feeding, improve production efficiency, and greatly reduce equipment costs. As for the injection process, the productivity can be increased by 50%.

[0004] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0005] A quantitative feeding device for a vacuum die-casting machine, comprising:

[0006] A vacuum exhaust system having an exhaust pipe connected to the mold cavity and / or the melting cup for evacuating the mold cavity and / or the melting cup;

[0007] An alloy melt holding furnace, which is connected to the bottom of the melting cup through one end of a riser pipe and is close to the punch injection starting position; the other end of the riser pipe away from the melting cup is located below the alloy melt surface of the alloy melt holding furnace;

[0008] The punch is arranged in the melting cup and is used to form a relatively sealed feeding space with the melting cup. The punch can move in the melting cup and is used to hydraulically inject the alloy melt in the melting cup into the mold cavity.

[0009] Preferably, it also includes:

[0010] An absolute pressure sensor, which is arranged at the exhaust pipe and is used to measure the vacuum degree;

[0011] An optical distance meter, which is arranged above the alloy melt holding furnace and is used to measure the distance from the bottom of the melting cup to the surface of the alloy melt in the alloy melt holding furnace;

[0012] An atmospheric pressure sensor, which is arranged in the control box of the vacuum exhaust system and is used to measure the atmospheric pressure of the environment;

[0013] The controller is arranged in the control box, and is used to receive the vacuum degree signal transmitted by the absolute pressure sensor, the distance signal transmitted by the optical rangefinder and the atmospheric pressure signal transmitted by the atmospheric pressure sensor, and display them on the operation screen, and control the vacuum exhaust system to evacuate and control the movement of the punch.

[0014] Preferably, the alloy melt holding furnace is located below the melting cup.

[0015] Preferably, the riser tube forms an acute angle a with respect to the direction opposite to the injection direction of the punch.

[0016] Preferably, the acute angle a is 45-65°.

[0017] Compared with the prior art, the utility model has the following beneficial effects:

[0018] 1) The quantitative feeding device for vacuum die-casting machine provided by the utility model omits the existing pouring port, connects the melting cup with the alloy solution insulation furnace by using a liquid riser, evacuates the vacuum exhaust system, and uses a punch to press the alloy solution in the melting cup into the mold cavity, wherein the process of absorbing liquid is the process of exhausting, which can improve or completely eliminate the filling rate, greatly improve the efficiency of die-casting quantitative feeding and die-casting vacuum exhaust, shorten the feeding and injection time, avoid the defects caused by the temperature drop of conventional aluminum alloy feeding, improve production efficiency, and greatly reduce equipment costs. As for the injection process, the productivity can be increased by 50%.

[0019] 2) The utility model uses a vacuum exhaust system to evacuate the mold cavity and / or the melting cup, and directly presses the molten alloy from the alloy solution insulation furnace into the melting cup through a liquid riser through a pressure difference, thereby reducing the temperature drop and oxidation reaction of the flow channel of the traditional quantitative furnace. The quantitative response time T replaces the quantitative and flow time of the traditional quantitative furnace and will be even shorter, because the alloy aluminum liquid in a vacuum state is directly fed from the bottom without a flow channel.

[0020] 3) The liquid riser of the utility model forms an acute angle a with respect to the direction of injection of the punch, which is more conducive to maintaining quantitative accuracy.

[0021] 4) The utility model arranges an optical distance meter above the alloy solution holding furnace to measure the height of the alloy melt, which has high accuracy and fast response, thus ensuring quantitative accuracy and great repeatability and reliability.

[0022] 5) The utility model adopts an absolute pressure sensor at the end of the mold or the top of the melting cup to indirectly measure the vacuum degree instantly formed in the melting cup and the mold cavity, which has high precision, fast response, extremely high reliability and repeatability.

[0023] 6) The quantitative feeding device for vacuum die-casting machine provided by the utility model, after the die is closed, the punch is in the starting position, and after receiving the command, the vacuum system starts vacuum exhaust through the mold cavity or the melting cup or both, and the air pressure in the mold cavity and the melting cup connected thereto drops (Ps), and after forming a pressure difference ΔP with the atmospheric pressure (P0), the alloy melt is gradually pressed into the melting cup through the inserted liquid riser until the set quantitative value is reached, and the injection begins; thus, the precise quantitative die-casting process of direct high-speed injection under extremely low pressure is realized. The precise quantitative, less temperature drop, less pores, and high productivity vacuum die-casting production of alloy castings, especially for large castings of integrated car bodies, is realized.

[0024] 7) The utility model uses the vacuum exhaust system of the vacuum die-casting machine to use the pressure difference to suck the alloy aluminum liquid into the melting cup, and realizes precise quantitative feeding through parameter ratio. At the same time, the vacuum makes the pressure of the melting cup and the mold cavity very low. The moment the quantitative feeding is completed, the injection can start, which greatly reduces the time from feeding to the end of injection. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the principle diagram of vacuum quantitative feeding of the utility model;

[0026] Figure 2 This is a schematic diagram of vacuum quantitative feeding of the utility model;

[0027] Figure 3 This is a schematic diagram of the vacuum quantitative feeding process of the utility model;

[0028] In the figure, 1. vacuum exhaust system; 2. mold cavity; 3. melting cup; 4. punch; 5. alloy solution holding furnace; 6. absolute pressure sensor; 7. optical rangefinder; 8. operation screen; 9. atmospheric pressure sensor; 10. control box; 11. exhaust pipe; 12. liquid riser. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model; it is obvious that the described embodiments are only part of the embodiments of the utility model, rather than all of the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the utility model without making creative work are within the scope of protection of the utility model.

[0030] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", "top / bottom" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0031] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "set / connected", "connected", etc. should be understood in a broad sense. For example, "connected" 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0032] like Figure 1-2 As shown, the utility model provides a quantitative feeding device for a vacuum die-casting machine, which omits the improvement made on the basis of the pouring port of the vacuum die-casting machine, and includes:

[0033] The vacuum exhaust system 1 has an exhaust pipe 11 connected to the mold cavity 2 and / or the melting cup 3, and is used to evacuate the mold cavity 2 and / or the melting cup 3. The vacuum exhaust system 1 can evacuate only the mold cavity 2 or the melting cup 3, or can evacuate both at the same time, which can be selected according to actual needs. The vacuum exhaust system 1 plays the role of both vacuum quantitative feeding and vacuum exhaust for die casting;

[0034] An alloy melt holding furnace, which is connected to the bottom of the melting cup 3 through one end of a riser pipe 12 and is close to the punch injection starting position; one end of the riser pipe 12 away from the melting cup 3 is located below the alloy melt surface of the alloy melt holding furnace, wherein the alloy melt holding furnace is preferably located below the melting cup 3;

[0035] The punch 4 is arranged in the melting cup 3, and is used to form a relatively sealed feeding space with the melting cup 3, and can move in the melting cup 3, and is used to hydraulically inject the alloy melt in the melting cup 3 into the mold cavity 2, wherein the punch 4 can be driven by a driving device, and the driving device can be a conventional driving device, such as a hydraulic cylinder, a driving motor, etc., which can be selected according to actual needs.

[0036] The quantitative feeding device for vacuum die-casting machine provided by the utility model evacuates the mold cavity 2 and / or the melting cup 3 through the vacuum exhaust system 1, presses the alloy solution in the alloy solution holding furnace 5 to the melting cup 3 by using the pressure difference, and injects the alloy solution in the melting cup 3 into the mold model by controlling the punch 4, so that the efficiency of quantitative feeding and vacuum exhaust of die casting is greatly improved, and the feeding and injection time is shortened, avoiding the defects caused by the temperature drop of conventional feeding of aluminum alloy, improving production efficiency, and greatly reducing equipment cost. In terms of the injection process, the productivity can be increased by 50%.

[0037] In the present invention, in order to realize automatic control, it also includes:

[0038] The absolute pressure sensor 6 is arranged at the exhaust pipe 11 and is used to measure the vacuum degree, and indirectly measure the vacuum degree in the mold cavity 2 and the melting cup 3, and has high precision, fast response, high reliability and repeatability;

[0039] An optical distance meter 7 is arranged above the alloy melt holding furnace and is used to measure the distance from the bottom of the melting cup 3 to the surface of the alloy melt in the alloy melt holding furnace. The optical distance meter 7 has high precision and fast response, ensuring quantitative accuracy and great repeatability and reliability;

[0040] An atmospheric pressure sensor 9, which is arranged in a control box 10 of the vacuum exhaust system 1 and is used to measure the atmospheric pressure of the environment;

[0041] The controller is arranged in the control box 10, and is used to receive the vacuum signal transmitted by the absolute pressure sensor 6, the distance signal transmitted by the optical rangefinder 7 and the atmospheric pressure signal transmitted by the atmospheric pressure sensor 9, and display them on the operation screen 8, and control the vacuum exhaust system 1 to evacuate and control the movement of the punch 4, wherein the controller can select a conventional controller in the field, such as a programmable logic controller (PLC), etc.

[0042] In the present invention, the alloy melt insulation furnace is located below the melting cup 3 .

[0043] In the present invention, the rising tube 12 forms an acute angle a with respect to the direction opposite to the injection direction of the punch 4, which is more conducive to maintaining the accuracy of quantitative feeding.

[0044] In the present invention, the acute angle a is 45-65°.

[0045] On the other hand, Figure 3 As shown, the utility model also provides a feeding method for the quantitative feeding device for the vacuum die-casting machine, comprising the following steps:

[0046] By using the principle of dynamic pressure difference and dynamic height difference, the quantitative weight is set, and precise quantitative feeding of aluminum alloy die-casting is achieved by balancing the pressure difference between the atmosphere and the mold cavity 2 and / or the vacuum of the melting cup 3 and the height difference between the melting cup 3 and the liquid level of the alloy melt holding furnace.

[0047] In the present invention, the following steps are specifically included:

[0048] Preparatory process: the die casting machine and other peripheral equipment enter the automatic cycle; the vacuum exhaust system 1 is at a static pressure below 5-10 mbar absolute; according to the process requirements, the quantitative weight value G of the product is set through the operation screen 8.

[0049] Mold closing in place: the cycle starts. After receiving this signal, the controller controls the atmospheric pressure sensor 9 to measure the ambient atmospheric pressure P0; the optical rangefinder 7 measures the distance h3 from the bottom of the melting cup 3 to the alloy liquid surface of the alloy solution holding furnace 5;

[0050] The mold cavity 2 and / or the melting cup 3 start to be evacuated: the exhaust pipe 11 of the vacuum exhaust system 1 is controlled by the controller to start evacuating. At this time, due to the pressure difference ΔP formed by the atmospheric pressure P0 and the vacuum Ps of the mold cavity 2 and the melting cup 3, the alloy melt is gradually pressed into the melting cup 3 through the liquid riser 12. At the same time, the controller controls the absolute pressure sensor 6 to continuously measure the vacuum degree Ps; the optical rangefinder 7 continuously measures the drop of the alloy liquid level h2; when the instant quantitative weight value G1 is equal to the set quantitative weight value G, the controller controls the quantitative end.

[0051] Injection starts: the controller controls the punch 4 to move forward, pushing the molten alloy in the melting cup 3 forward and closing the riser 12 at the bottom of the melting cup 3; at this time, the vacuum of the mold cavity 2 and / or the vacuum of the melting cup 3 will continue to be evacuated until the corresponding end signal is received and stopped; when the punch 4 completely passes over the top of the riser 12 of the melting cup 3, the remaining molten alloy in the riser 12 will flow back to the alloy solution insulation furnace 5 by gravity due to the lack of pressure difference, and continue to be kept warm.

[0052] End of injection: At this time, the filling and vacuum are finished. The die casting enters the pressure-maintaining cooling state.

[0053] Mold opening in place: After the robot takes out the parts, the vacuum exhaust system 1 pipeline blockage test, backflush cleaning and mold surface cleaning, it returns to the mold closing in place state and waits for the next cycle;

[0054] Next time the mold is closed: the next cycle starts and the above actions are repeated;

[0055] All the above settings and operations will be completed on the operation screen 8 located on the operation side and are controlled by the controller.

[0056] The utility model uses the controller to control the principle as follows:

[0057] In each injection cycle, the utility model can obtain instant quantitative G1=f(h2)=G by setting the quantitative weight value G and the liquid level drop h2 of the alloy solution holding furnace 5 under the constant inner diameter Db, but it is not advisable because Db is not smooth and constant; instead, the pressure difference principle H*γ=(h1+h2+h3)*γ=ΔP=P0-Ps is used, where γ is known, and P0, h2 and h3 are measured to know that the aluminum alloy liquid level in the melting cup 3 is h1=f(Ps); at the same time, the establishment of h1 is related to the time T, which is revised to h1=f(Ps,T), then the instant quantitative G1=f(h1)=f(Ps,T), and finally the quantitative end is reached with G1=G. Where Ps determines the quantitative accuracy, and T determines the quantitative response.

[0058] The mold cavity 2 or the melting cup 3 or both are evacuated by the vacuum exhaust system 1. When the value of Ps meets the quantitative weight value G at time T, the process will continue until it is stopped due to the end of process control. At this time, the vacuum formed in the melting cup 3 and the mold cavity 2 allows the injection to start at a higher speed, reducing the low-speed injection process, thanks to the fact that the air entrainment in the alloy melt is greatly eliminated under vacuum.

[0059] The utility model adopts the pressure difference between atmosphere and vacuum to add materials, and the quantitative amount is only related to the instantaneous vacuum degree and the response time; the area of ​​the vacuum exhaust system 1 and the exhaust valve connected thereto is directly proportional to the decrease of the absolute vacuum value, that is, it is directly proportional to the atmospheric pressure difference; and it is inversely proportional to the response time; the sealing factor will affect the response time; when the response time is too long, it is necessary to strengthen the overall sealing, including the mold itself, the melting cup 3 and the punch 4, etc.

[0060] In summary, the above-mentioned quantitative feeding device and feeding method for vacuum die-casting machine provided by the utility model have opened up another precise quantitative feeding method. After the vacuum exhaust system 1 becomes an indispensable means, it provides a selectivity of quantitative feeding method without changing the process. Compared with the traditional quantitative furnace, the vacuum exhaust system 1 is evacuated, and the alloy aluminum melt is pressed into the melting cup 3 by utilizing the pressure difference between vacuum and atmospheric pressure. The quantitative feeding is realized while the vacuum exhaust is being performed, which saves about half of the total feeding and exhausting time. When the quantitative feeding is completed, the injection can start immediately, which reduces the process time and improves the production efficiency. The quantitative feeding through the riser pipe 12 under the surface of the alloy solution holding furnace 5 also avoids the oxidation of the alloy and maintains the purity of the raw materials. The gold solution holding furnace 5 directly presses the molten alloy into the melting cup 3 through the riser pipe 12 without passing through an open material trough, which greatly reduces the temperature drop during the alloy feeding process and ensures the filling fluidity of the alloy melt required for injection; the vacuum will be completed as the injection is completed, or the injection process ends at a given position, and continuous vacuum exhaust will be achieved without being affected by the quantitative completion, thereby minimizing the porosity of the casting; when the punch 4 passes over the top interface of the riser pipe 12, the aluminum alloy melt in the riser pipe 12 will fall back into the holding furnace by gravity and wait for the next dosing process without the need for additional recovery and insulation; this reduces the total time of the injection process, improves productivity, reduces temperature drop and precise dosing, reduces porosity, and provides a practical vacuum quantitative feeding solution for super-large castings, especially new energy integrated car bodies.

[0061] Among them, the above alloy solution may preferably be an aluminum alloy solution.

[0062] The above are only preferred specific implementations of the utility model; however, the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solution and improved ideas of the utility model within the technical scope disclosed by the utility model, which should be included in the protection scope of the utility model.

Claims

1. A quantitative feeding device for a vacuum die casting machine, characterized in that: include: A vacuum exhaust system having an exhaust pipe connected to the mold cavity and / or the melting cup for evacuating the mold cavity and / or the melting cup; An alloy melt holding furnace, which is connected to the bottom of the melting cup through one end of a riser pipe and is close to the punch injection starting position; the other end of the riser pipe away from the melting cup is located below the alloy melt surface of the alloy melt holding furnace; The punch is arranged in the melting cup and is used to form a relatively sealed feeding space with the melting cup. The punch can move in the melting cup and is used to hydraulically inject the alloy melt in the melting cup into the mold cavity.

2. A quantitative feeding device for a vacuum die-casting machine according to claim 1, characterized in that: Also includes: An absolute pressure sensor, which is arranged at the exhaust pipe and is used to measure the vacuum degree; An optical distance meter, which is arranged above the alloy melt holding furnace and is used to measure the distance from the bottom of the melting cup to the surface of the alloy melt in the alloy melt holding furnace; An atmospheric pressure sensor, which is arranged in the control box of the vacuum exhaust system and is used to measure the atmospheric pressure of the environment; The controller is arranged in the control box, and is used to receive the vacuum degree signal transmitted by the absolute pressure sensor, the distance signal transmitted by the optical rangefinder and the atmospheric pressure signal transmitted by the atmospheric pressure sensor, and display them on the operation screen, and control the vacuum exhaust system to evacuate and control the movement of the punch.

3. A quantitative feeding device for a vacuum die-casting machine according to claim 1, characterized in that: The alloy melt insulation furnace is located below the melting cup.

4. A quantitative feeding device for a vacuum die-casting machine according to any one of claims 1 to 3, characterized in that: The rising tube forms an acute angle a with respect to the direction opposite to the injection direction of the punch.

5. A quantitative feeding device for a vacuum die-casting machine according to claim 4, characterized in that: The acute angle a is 45 to 65 degrees.

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