Injection molding machine for underground box production

Abstract

The invention relates to the technical field of injection molding machines, in particular to an injection molding machine for buried box production, a front mold transmission assembly is adopted and comprises a workbench, an injection molding pipeline, a rear mold and a front mold, one end of the injection molding pipeline is in transmission connection with a screw rod driving assembly, and the screw rod driving assembly drives the injection molding pipeline to rotate and axially move; one side of the front mold is in transmission connection with a hydraulic transmission assembly, the hydraulic transmission assembly drives the front mold to move close to or away from the rear mold, and a front mold transmission assembly is connected between the hydraulic transmission assembly and the front mold, so that the flowability of liquid PP can be improved, the liquid PP can flow to the position between the front mold and the rear mold more quickly, and the flowability of the liquid PP is improved. The liquid PP can be quickly filled in the reinforcing ribs, the movement starting time of the front mold can be greatly shortened through the driving mode of the electromagnets, the acceleration of the front mold is controlled by providing damping, and then the flowing speed of the liquid PP is accurately controlled, so that the production requirements of the buried box are met.

Description

Technical Field

[0001] The present invention relates to the technical field of injection molding machines, and particularly to an injection molding machine for producing buried boxes Background Art

[0002] The material of the buried box is polypropylene, a kind of PP. The buried box solves the waterproof problem through underground sealing treatment. Through the unique fence-shaped reinforcing rib design, the heat dissipation and heat preservation problems in the internal environment are effectively realized. It is injection-molded at one time with high-quality materials and has the characteristics of earthquake resistance, corrosion resistance, acid and alkali resistance, etc. The bearing strength of the battery buried box is high. The common production method is integral injection molding, so an injection molding machine will be used for production

[0003] The Chinese patent with the publication number of CN118876370A discloses a self-cooling mold for injection molding of turbine parts, including a lower mold base and an upper mold base. An injection hole is opened in the upper mold base, and a second solenoid valve is arranged in the injection hole. A groove is opened in the lower mold base, and a self-cooling mechanism is arranged in the lower mold base; the self-cooling mechanism includes two liquid tanks, a function cavity, a communication cavity and a liquid storage cavity opened in the lower mold base. The communication cavity connects the two liquid tanks with the function cavity. A piston is hermetically and slidably connected in the liquid tank, and a positioning column is detachably connected to the upper surface of the piston. The positioning column is fixedly connected to the lower surface of the upper mold base. A lower slide plate and an upper slide plate are hermetically and slidably connected in the function cavity. The advantage is that injection molding can be automatically stopped and cooled when the injection pressure reaches a certain value, which is more convenient to use, and it avoids the occurrence of defective products easily caused by manual control, and the cooling effect is better, and it is more convenient to demold

[0004] In the prior art, after injection molding and cooling, an ejection mechanism is required to eject the produced product. Due to the shape characteristics of the buried box, it has fence-shaped reinforcing ribs on the outside. While providing a certain strength support, the reinforcing ribs also help to provide part of the heat dissipation function. Due to the shape and thickness characteristics of the fence-shaped reinforcing ribs, the thinner reinforcing ribs are more likely to quickly cool down during the flow process, causing them to turn into solids in advance during the injection molding process, resulting in local insufficient filling problems in the mold Summary of the Invention

[0005] In view of the above-mentioned drawbacks of the prior art, the present invention provides an injection molding machine for producing buried boxes to solve the problems raised in the above background art

[0006] To achieve the above object, the present invention is realized through the following technical solutions The present invention provides an injection molding machine for the production of underground boxes, which includes a workbench, an injection molding pipeline, a rear mold and a front mold. One end of the injection molding pipeline is drivingly connected with a screw driving assembly, and the screw driving assembly drives the injection molding pipeline to rotate and move axially. One side of the front mold is drivingly connected with a hydraulic driving assembly, and the hydraulic driving assembly drives the front mold to move closer to or away from the rear mold. A front mold driving assembly is connected between the hydraulic driving assembly and the front mold; The front mold driving assembly includes a driving rod fixedly connected to the output shaft of the hydraulic driving assembly. The end of the driving rod has a groove, and an electromagnet is fixedly connected in the groove. One side of the front mold is fixedly connected with a flange plate. One side of the flange plate is fixedly connected with a moving rod. The moving rod is slidably inserted into the groove at the end of the driving rod, and a force-bearing magnet is fixedly connected to the end of the moving rod. The force-bearing magnet is affected by the magnetic force of the electromagnet. The electromagnet is connected to a frequency converter and changes the frequency of the alternating current through the frequency converter to change the frequency of the change of the magnetic pole of the electromagnet; A sealing sleeve is fixedly connected to the outside of the rear mold. The sealing sleeve includes a sealing housing as the main body. The front mold slides in the sealing housing, and a closed space is formed between the rear mold and the front mold by the sealing housing.

[0007] As a further scheme of the present invention, one end of the driving rod is fixedly connected with a cylinder body. A piston is slidably connected in the cylinder body. One side of the piston is fixedly connected with a connecting rod. The connecting rod is slidably inserted into the side plate of the cylinder body and one end is fixedly connected to the flange plate. Both side plates of the cylinder body are fixedly connected with air discharge pipes through holes. Air discharge grooves are provided on the air discharge pipes. The air discharge grooves are in the shape of a safety pin, and both ends of the air discharge grooves are respectively connected to the internal cavity and the outside of the cylinder body.

[0008] As a further scheme of the present invention, a plurality of semiconductor refrigeration chips are fixedly embedded on the piston, and the semiconductor refrigeration chips are electrically connected to the frequency converter.

[0009] As a further scheme of the present invention, heat-conducting metal sheets are fixedly connected to both side plates of the piston and the inner walls of both side plates of the cylinder body. The heat-conducting metal sheets are located corresponding to the semiconductor refrigeration chips. A plurality of V-shaped heat-conducting sheets are fixedly connected to one side of the heat-conducting metal sheets, and connecting sheets are fixedly connected between the V-shaped heat-conducting sheets.

[0010] As a further scheme of the present invention, the sealing sleeve further includes air vent grooves opened at partial positions on the top plate and both side plates of the sealing housing. The edges of the air vent grooves are aligned with the edges of the rear mold. Pressure guiding frames are fixedly connected to the outside of the sealing housing corresponding to the air vent grooves. Negative pressure transmission pipes are fixedly connected to the top and both side positions of the pressure guiding frames, and the negative pressure transmission pipes are all fixedly connected to a negative pressure vacuum pump.

[0011] As a further aspect of the present invention, the injection molding pipe includes an injection molding housing as an outer housing and an injection molding screw disposed within the injection molding housing. A hydraulic oil conduction cylinder is fixedly connected to the end of the injection molding screw. An expansion bladder is fixedly connected to the circumferential side of the hydraulic oil conduction cylinder. Both ends of the expansion bladder are fixedly connected with connection rings. A slot is formed at a position of the hydraulic oil conduction cylinder close to the injection molding screw. The hydraulic oil within the hydraulic oil conduction cylinder can enter the expansion bladder through this slot. A pressing disk is slidably connected within the hydraulic oil conduction cylinder. A stop rod is fixedly installed on the side plate of the hydraulic oil conduction cylinder, and the end of the stop rod corresponds to the edge of the slot of the hydraulic oil conduction cylinder. When the pressing disk contacts the stop rod, the position where the pressing disk is located has not yet passed through the slot of the hydraulic oil conduction cylinder. A sealing ring is fixedly connected to the outer side of the injection molding housing close to the injection nozzle. An oil liquid pipe is fixedly connected through the sealing ring. A fixing block is fixedly installed on the outer side of the oil liquid pipe. A liquid injection pipe is fixedly connected to the side of the fixing block facing the hydraulic oil conduction cylinder, and the liquid injection pipe is fixedly connected to and communicates with the oil liquid pipe.

[0012] As a further aspect of the present invention, a first communication pipe is fixedly connected through the center of the pressing disk. A fixing ring is fixedly connected within the first communication pipe. One side of the fixing ring is fixedly connected with a first blocking block through a spring. The first blocking block covers the port of the first communication pipe through the elastic tension of the spring. The oil liquid pipe is connected to a hydraulic pump. A fixing frame is fixedly connected within the oil liquid pipe. A fixing frame is fixedly connected within the liquid injection pipe. One side of the fixing frame is fixedly connected with a second blocking block through a spring. The end of the liquid injection pipe is reduced in diameter inward, and the second blocking block is slidably connected within the reduced-diameter end of the liquid injection pipe. A top rod is fixedly connected to the inner wall of the side plate of the hydraulic oil conduction cylinder. When the liquid injection pipe contacts the first communication pipe, the end of the liquid injection pipe is sleeved outside the first communication pipe. As the pressing disk and the first communication pipe slide towards the top rod, the top rod will contact the first blocking block. Then, the spring on the first blocking block is stretched, and the first blocking block contacts the second blocking block within the liquid injection pipe, causing the second blocking block to slide into the liquid injection pipe from the end of the liquid injection pipe, enabling the liquid injection pipe to communicate with the first blocking block. The diameter of the liquid injection pipe is the same as that of the first communication pipe.

[0013] As a further aspect of the present invention, a hydraulic conduction pipe is fixedly connected through the fixing block and the sealing ring together, and the end of the hydraulic conduction pipe extends from the sealing ring to the outside and communicates with a hydraulic pump. A simple hydraulic telescopic rod is fixedly connected to one side of the fixing block. One of the connection rings is fixedly installed at the end of the hydraulic oil conduction cylinder close to the injection molding screw, and the other connection ring is slidably sleeved outside the hydraulic oil conduction cylinder.

[0014] The technical solution provided by the present invention has the following beneficial effects compared with the known public technologies: By adopting the front mold drive assembly, the present invention can improve the fluidity of liquid PP, enabling the liquid PP to flow faster between the front mold and the rear mold and quickly fill the ribbed part. Moreover, the driving mode of the electromagnet can greatly shorten the starting time of the movement of the front mold, and by providing damping, the acceleration of the front mold can be controlled, thereby accurately controlling the flow rate of the liquid PP to meet the production requirements of the buried box. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0016] Figure 1 is a schematic diagram of the overall structure of the present invention; Figure 2 is a schematic diagram of a partial structure of the present invention; Figure 3 is a schematic diagram of the semi-sectional structure of the front mold drive assembly of the present invention; Figure 4 is of the present invention Figure 3 enlarged view at A; Figure 5 is a schematic diagram of the structure at the piston of the present invention; Figure 6 is a schematic diagram of the injection molding pipeline of the present invention; Figure 7 is a schematic diagram of the internal structure of the injection molding pipeline of the present invention; Figure 8 is a schematic diagram of the structure at the fixed block of the present invention (one); Figure 9 is a schematic diagram of the structure at the fixed block of the present invention (two); Figure 10 is a schematic diagram of the internal structure of the hydraulic oil conduction cylinder of the present invention; Figure 11 is a semi-sectional schematic diagram of the sealing sleeve housing of the present invention.

[0017] The reference numerals in the figure respectively represent: 1, workbench; 2, injection molding pipeline; 201, injection molding housing; 202, injection molding screw; 203, hydraulic oil conduction cylinder; 204, expansion bladder; 205, connecting ring; 206, pressing disc; 207, first communication pipe; 208, first blocking block; 209, fixing ring; 210, sealing ring; 211, fixing block; 212, hydraulic transmission pipe; 213, simple hydraulic telescopic rod; 214, oil pipe; 215, second blocking block; 216, fixing frame; 217, stop rod; 218, ejector rod; 219, liquid injection pipe; 3, rear mold; 4, front mold; 5, hydraulic transmission assembly; 6, screw drive assembly; 7, front mold drive assembly; 701, transmission rod; 702, electromagnet; 703, force receiving magnet; 704, moving rod; 705, flange; 706, cylinder body; 707, air release pipe; 708, connecting rod; 709, piston; 710, semiconductor refrigeration sheet; 711, heat conducting metal sheet; 712, V-shaped heat conducting sheet; 713, connecting sheet; 8, sealing sleeve housing; 801, sealing housing; 802, ventilation groove; 803, pressure guiding frame body; 804, negative pressure transmission pipe. Detailed implementation mode

[0018] In order to make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] The present invention will be further described below with reference to the embodiments.

[0020] Embodiment 1, as Figures 1 to 5 shown, an injection molding machine for producing buried boxes includes a workbench 1, an injection molding pipeline 2, a rear mold 3 and a front mold 4. One end of the injection molding pipeline 2 is drivingly connected to a screw drive assembly 6. The screw drive assembly 6 drives the injection molding pipeline 2 to rotate and axially move. One side of the front mold 4 is drivingly connected to a hydraulic transmission assembly 5. The hydraulic transmission assembly 5 drives the front mold 4 to move closer to or away from the rear mold 3. A front mold drive assembly 7 is connected between the hydraulic transmission assembly 5 and the front mold 4; The front mold drive assembly 7 includes a drive rod 701 fixedly connected to the output shaft of the hydraulic drive assembly 5. The end of the drive rod 701 has a groove, and an electromagnet 702 is fixedly connected in the groove. One side of the front mold 4 is fixedly connected with a flange plate 705. One side of the flange plate 705 is fixedly connected with a moving rod 704. The moving rod 704 is slidably inserted into the groove at the end of the drive rod 701, and the end of the moving rod 704 is fixedly connected with a force-receiving magnet 703. The force-receiving magnet 703 is affected by the magnetic force of the electromagnet 702. The electromagnet 702 is connected to a frequency converter and changes the frequency of the alternating current through the frequency converter to change the frequency of the pole change of the electromagnet 702; A sealing sleeve housing 8 is fixedly connected to the outside of the rear mold 3. The sealing sleeve housing 8 includes a sealing housing body 801 as the main body. The front mold 4 slides in the sealing housing body 801, and the sealing housing body 801 forms a closed space between the rear mold 3 and the front mold 4.

[0021] When the device is working, small plastic particles gradually fall from the feeding barrel into the injection molding shell 201, and are rotated and pushed toward the injection nozzle of the injection molding shell 201 by the injection molding screw 202. In this process, the heating component outside the injection molding shell 201 and the tangential force generated by the rotation of the injection molding screw 202 will gradually heat the small plastic particles to a liquid state. After the small plastic particles are melted to a certain amount, the injection molding screw 202 moves toward the injection nozzle of the injection molding shell 201 to inject the plastic between the rear mold 3 and the front mold 4. In the production of buried boxes, PP material is mostly used. This material has good physical properties and can remain sealed underground for a long time. It usually has fence-like reinforcement ribs to enhance local strength and increase heat dissipation. In the production process, the injection During the injection molding, the front mold 4 is driven by the hydraulic transmission component 5 to press against one side of the rear mold 3, and provides pressure during the injection molding process to ensure that the front mold 4 is close to the rear mold 3, so that the PP forms a buried box shape between the rear mold 3 and the front mold 4. In this process, the melted PP will flow between the rear mold 3 and the front mold 4, forming a reinforcing rib structure where needed. In order to improve the fluidity of PP, during the injection molding process, the electromagnet 702 is powered by an external power supply, and the frequency of the alternating current is adjusted by a frequency converter. After the frequency of the alternating current changes, the magnetic pole of the electromagnet 702 facing the force magnet 703 will change at a certain frequency, and the force magnet 703 will be subjected to the suction and repulsion of a certain frequency change. The constantly changing suction and repulsion will make the force magnet 703 move. Stable reciprocating motion, the front mold 4 fixed with the force magnet 703 will reciprocate with a certain amplitude, and because the range of the magnetic field is small, it is suitable for small-range driving. At the same time, compared with hydraulic pressure as a transmission medium, the magnetic force acts faster, and the frequency of changing the direction of action is easier to adjust. The frequency converter, a simple component, can be used to quickly change the reciprocating frequency, and the magnitude of the force can be controlled by adjusting the current, so as to achieve stable control. Under the action of the magnetic force and the control of the current, the front mold 4 reciprocates in the sealed shell 801. During the injection molding process, since the sliding process of the front mold 4 in the sealed shell 801 is similar to the piston movement, when the front mold 4 is away from the rear mold 3, the injection molding The liquid PP flowing out of the shell 201 is sucked into the space between the rear mold 3 and the front mold 4, so that the flow speed of the liquid PP in the rear mold 3 and the front mold 4 can be quickly changed in a short time, and the fluidity of the liquid PP can be improved, so that the liquid PP can flow into the space between the rear mold 3 and the front mold 4 faster. In this way, the liquid PP can flow into the mold range of the reinforcing rib more easily, that is, the liquid PP is better filled in the range of the reinforcing rib, and at the same time, the speed of the liquid PP flowing to various places can be improved, and the speed of liquid PP filling can be accelerated. In addition, the small force range of the electromagnet 702 will not cause the liquid PP to flow too fast, resulting in the liquid PP being locally cooled to a solid state between the rear mold 3 and the front mold 4, nor will it be due to the large distance between the rear mold 3 and the front mold 4.Excessive liquid PP is filled in the rear mold 3 and the front mold 4. When the front mold 4 is attached to the rear mold 3, the liquid PP accumulates at the lower positions of the rear mold 3 and the front mold 4, causing the front mold 4 to be unable to make the liquid PP fill the space between the rear mold 3 and the front mold 4 under pressure. When the amount of liquid PP reaches the requirement, the injection molding work is stopped. The cooling components in the rear mold 3 and the front mold 4 gradually reduce the temperature of the liquid PP, quickly cooling the PP to a solid state, and then demolding it from the front mold 4.

[0022] One end of the transmission rod 701 is fixedly connected to a cylinder body 706. A piston 709 is slidably connected inside the cylinder body 706. One side of the piston 709 is fixedly connected to a connecting rod 708. The connecting rod 708 is slidably inserted through the side plate of the cylinder body 706 and one end is fixedly connected to the flange 705. Both side plates of the cylinder body 706 are fixedly connected through exhaust pipes 707. The exhaust pipes 707 are provided with exhaust grooves. The exhaust grooves are in the shape of a safety pin, and the two ends of the exhaust grooves are respectively connected to the internal cavity and the outside of the cylinder body 706.

[0023] During the reciprocating process of the force-bearing magnet 703, the force-bearing magnet 703 drives the flange 705 on the moving rod 704 to move. Through the connection between the flange 705 and the front mold 4, the front mold 4 is then driven to move. During the reciprocating movement of the flange 705, the flange 705 drives the piston 709 to reciprocate inside the cylinder body 706 through the transmission of the connecting rod 708. During the reciprocating process of the piston 709 in the cylinder body 706, the cavity on one side of the piston 709 will be squeezed, generating a relatively large pressure in some areas of the cylinder body 706. Relatively, a negative pressure is generated in the cavity on the other side of the piston 709, thus creating a pressure difference with the outside of the cylinder body 706. This part of the pressure difference is transmitted to the outside through the exhaust pipe 707. In this process, when air enters or leaves the cylinder body 706, it must pass through the safety-pin-shaped exhaust grooves of the exhaust pipe 707. Due to the small aperture of the safety-pin-shaped exhaust grooves and the shape of the safety pin that hinders the flow of air, it plays a certain role in hindering the transmission of air pressure. Therefore, during the reciprocating process of the front mold 4, this part of the air pressure difference will have a certain damping effect on the reciprocating movement of the front mold 4 when passing through the exhaust pipe 707, restricting the moving speed of the front mold 4. Since the starting speed of the electromagnet 702 is relatively fast, that is, the acceleration obtained by the front mold 4 is relatively large, this part of the damping can limit the magnitude of the acceleration of the front mold 4, avoiding the excessive flow speed of the liquid PP resulting in an increase in contact with the air inside the rear mold 3 and the front mold 4, and forming bubbles in the PP. The sealing performance of the buried box with bubbles will be greatly reduced. Therefore, it is necessary to avoid the generation of bubbles.

[0024] A plurality of semiconductor refrigeration chips 710 are fixedly embedded on the piston 709. The semiconductor refrigeration chips 710 are electrically connected to the frequency converter.

[0025] The air pressure difference between the outside and the inside of the cylinder 706 is an important factor in providing damping. The temperature change generated by the thermoelectric cooler 710 can change the pressure of the gas in the enclosed space, so it can change the damping. At the same time, the temperature change on the thermoelectric cooler 710 is relatively fast. By changing the magnitude of the current, the power of the thermoelectric cooler 710 can be quickly changed to change the speed of temperature change. At the same time, in the enclosed space, the temperature change will quickly change the gas pressure, and then can quickly change the damping magnitude. At the same time, using gas as the damping medium, compared with liquid, the compressible characteristic of gas can provide damping more stably during the movement process of small amplitude and quickly changing the movement direction, and can also control the air pressure magnitude through the adjustment of the current magnitude under the action of the control system to quickly increase the damping effect. When the thermoelectric cooler 710 acts, the air pressure on one side of the piston 709 increases and the air pressure on the other side decreases. Then, during this process, the air pressure difference between the cylinder 706 and the outside is increased. When the cylinder 706 moves, the increased air pressure difference during the movement is superimposed on the air pressure difference brought by the temperature change, which will make the movement of the cylinder 706 more difficult, and then can better reduce the acceleration of the front mold 4. It can be understood that when the thermoelectric cooler 710 does not work, the damping value received by the cylinder 706 is the smallest. After the thermoelectric cooler 710 works, the air pressure difference between the cylinder 706 and the outside is increased, and the damping value at this time is larger.

[0026] Both side plates of the piston 709 and the inner walls of both side plates of the cylinder 706 are fixedly connected with heat-conducting metal sheets 711. The heat-conducting metal sheets 711 correspond to the position of the thermoelectric cooler 710. One side of the heat-conducting metal sheet 711 is fixedly connected with a plurality of V-shaped heat-conducting sheets 712, and connecting sheets 713 are fixedly connected between the V-shaped heat-conducting sheets 712.

[0027] During the working process of the thermoelectric cooler 710, the temperature is transferred to the V-shaped heat-conducting sheets 712, and through the contact between the V-shaped heat-conducting sheets 712 and the gas, the gas temperature can be changed more quickly to change the acceleration magnitude of the front mold 4 to meet the production requirements. During the reciprocating process of the cylinder 706, the V-shaped heat-conducting sheets 712 will be folded or unfolded to ensure continuous contact with the gas.

[0028] Embodiment 2, on the basis of Embodiment 1, as Figures 6 to 10 shown, The injection molding pipe 2 includes an injection molding housing 201 as an outer housing and an injection molding screw 202 disposed within the injection molding housing 201. A hydraulic oil conduction cylinder 203 is fixedly connected to the end of the injection molding screw 202. An expansion bladder 204 is fixedly connected to the circumferential side of the hydraulic oil conduction cylinder 203. Connecting rings 205 are fixedly connected to both ends of the expansion bladder 204. A slot is formed at a position of the hydraulic oil conduction cylinder 203 close to the injection molding screw 202. The hydraulic oil within the hydraulic oil conduction cylinder 203 can enter the expansion bladder 204 through this slot. A pressing disk 206 is slidably connected within the hydraulic oil conduction cylinder 203. A stop rod 217 is fixedly installed on the side plate of the hydraulic oil conduction cylinder 203. The end of the stop rod 217 corresponds to the edge of the slot of the hydraulic oil conduction cylinder 203. When the pressing disk 206 contacts the stop rod 217, the position where the pressing disk 206 is located has not yet passed through the slot of the hydraulic oil conduction cylinder 203. A sealing ring 210 is fixedly connected to the outer side of the injection molding housing 201 near the injection nozzle. An oil pipe 214 is fixedly connected through the sealing ring 210. A fixing block 211 is fixedly installed on the outer side of the oil pipe 214. A liquid injection pipe 219 is fixedly connected to the side of the fixing block 211 facing the hydraulic oil conduction cylinder 203, and the liquid injection pipe 219 is fixedly connected to and communicates with the oil pipe 214.

[0029] During the injection molding process, the injection molding screw 202 will move only axially under the drive of a hydraulic mechanism, and push the liquid PP within the injection molding housing 201 out from the injection nozzle of the injection molding housing 201. As the injection molding screw 202 moves, the pressing disk 206 will contact the liquid injection pipe 219 on the fixing block 211. Under the relative movement between the hydraulic oil conduction cylinder 203 and the liquid injection pipe 219, the liquid injection pipe 219 will push the pressing disk 206 within the hydraulic oil conduction cylinder 203 towards the stop rod 217, and push the hydraulic oil within the hydraulic oil conduction cylinder 203 into the expansion bladder 204 through the slot of the hydraulic oil conduction cylinder 203. With the replenishment of the hydraulic oil, the volume of the expansion bladder 204 within the injection molding housing 201 gradually increases. The expanding expansion bladder 204 will generate a thrust on the liquid PP. While the injection molding screw 202 extrudes the liquid PP, the expansion bladder 204 helps to extrude the liquid PP to make up for the amount of liquid PP sucked out by negative pressure when the front mold 4 moves away from the rear mold 3, and helps to extrude the liquid PP. At the same time, it can be understood that when the hydraulic oil returns to the hydraulic oil conduction cylinder 203, the volume of the expansion bladder 204 within the injection molding housing 201 rapidly decreases, that is, at the moment when the injection molding work ends, along with the retraction of the injection molding screw 202, the amount of liquid PP near the injection nozzle of the injection molding housing 201 rapidly decreases, which can help the liquid PP to quickly return into the injection molding housing 201 and avoid drooling near the injection nozzle.

[0030] A fixing ring 209 is fixedly connected inside the first connecting pipe 207. One side of the fixing ring 209 is fixedly connected with a first blocking block 208 through a spring. The first blocking block 208 covers the port of the first connecting pipe 207 through the elastic tension of the spring. The oil pipe 214 is connected to the hydraulic pump. A fixing frame 216 is fixedly connected inside the oil pipe 214. A fixing frame 216 is fixedly connected inside the liquid injection pipe 219. One side of the fixing frame 216 is fixedly connected with a second blocking block 215 through a spring. The end of the liquid injection pipe 219 is reduced in diameter inward, and the second blocking block 215 is slidably connected inside the reduced-diameter end of the liquid injection pipe 219. A push rod 218 is fixedly connected to the inner wall of the side plate of the hydraulic oil conduction cylinder 203. When the liquid injection pipe 219 contacts the first connecting pipe 207, the end of the liquid injection pipe 219 is sleeved outside the first connecting pipe 207. And as the pressing disc 206 and the first connecting pipe 207 slide towards the push rod 218, the push rod 218 will contact the first blocking block 208. Then the spring on the first blocking block 208 is stretched. The first blocking block 208 contacts the second blocking block 215 inside the liquid injection pipe 219, and the second blocking block 215 is made to slide into the liquid injection pipe 219 from the end of the liquid injection pipe 219, so that the liquid injection pipe 219 communicates with the first blocking block 208. The diameter of the liquid injection pipe 219 is the same as that of the first connecting pipe 207.

[0031] When the liquid injection pipe 219 contacts the first connecting pipe 207, the end of the liquid injection pipe 219 is sleeved outside the first connecting pipe 207. Together with the first blocking block 208 outside the first connecting pipe 207, they are all shrouded inside the end of the liquid injection pipe 219 until the push rod 218 extends into the first connecting pipe 207, exerting a squeezing effect on the first blocking block 208. And through the contact between the first blocking block 208 and the second blocking block 215 inside the liquid injection pipe 219, the first blocking block 208 and the second blocking block 215 are made to extend into the liquid injection pipe 219 together. As the second blocking block 215 leaves the range of the end of the liquid injection pipe 219, the ends of the liquid injection pipe 219 and the first connecting pipe 207 are connected nearby, and at this time the liquid injection pipe 219 and the first connecting pipe 207 are firmly attached to each other under the action of pressure. The hydraulic pressure can be transmitted to the inside of the liquid injection pipe 219 through the oil pipe 214 and further transmitted to the expansion bladder 204 through the hydraulic oil conduction cylinder 203. In this way, the hydraulic oil in the expansion bladder 204 can continue to be increased, making the volume of the expansion bladder 204 further increase, further helping to extrude the liquid PP inside the injection molding housing 201. At the same time, the amount of the extruded liquid PP is the same as the volume of the hydraulic oil supplemented from the oil pipe 214 into the hydraulic oil conduction cylinder 203. In this way, the extrusion amount of the liquid PP can be better controlled, adjusted to the actual required liquid PP content of the buried box, and it can also be during the production process, after the injection molding screw 202 stops axially moving, the extrusion speed and extrusion amount of the liquid PP can also be adjusted by adjusting the hydraulic oil conduction to cooperate with the reciprocating movement of the front mold 4 to suck the liquid PP.

[0032] The fixed block 211 and the sealing ring 210 are jointly penetrated and fixedly connected with a hydraulic transmission pipe 212, and the end of the hydraulic transmission pipe 212 extends from the sealing ring 210 to the outside and is communicated with a hydraulic pump. One side of the fixed block 211 is fixedly connected with a simple hydraulic telescopic rod 213. One of the connecting rings 205 is fixedly installed at the end of the hydraulic oil conduction cylinder 203 close to the injection screw 202, and the other connecting ring 205 is slidably sleeved outside the hydraulic oil conduction cylinder 203.

[0033] The simple hydraulic telescopic rod 213 is connected to an external hydraulic pump through the hydraulic transmission pipe 212. The extended distance of the simple hydraulic telescopic rod 213 can be adjusted by controlling the hydraulic pressure. After the simple hydraulic telescopic rod 213 extends a certain distance, when the expansion bladder 204 moves towards the simple hydraulic telescopic rod 213, the contact time between the connecting ring 205 and the simple hydraulic telescopic rod 213 can be made earlier than the contact time between the liquid injection pipe 219 and the first connecting pipe 207. In this way, the expansion bladder 204 will first change its shape. When the hydraulic oil enters the inside of the expansion bladder 204, the diameter of the expansion bladder 204 has already increased. Under the action of the pressure of the liquid PP, the expansion bladder 204 will increase its folds and diameter. The pressure of the liquid PP on both sides of the folds of the expansion bladder 204 is the same. When the hydraulic oil enters the expansion bladder 204, the hydraulic oil can enter the expansion bladder 204 more smoothly, avoiding the situation that the pressure of the liquid PP is too large and causing difficulty for the hydraulic oil to enter. When the hydraulic pressure in the simple hydraulic telescopic rod 213 is small, the simple hydraulic telescopic rod 213 can be completely retracted. At this time, the length of the simple hydraulic telescopic rod 213 is shorter than that of the liquid injection pipe 219, so the simple hydraulic telescopic rod 213 will not contact the connecting ring 205 throughout the process. The corresponding state is that the entry of the hydraulic oil at this time does not require the cooperation of the shape of the expansion bladder 204.

[0034] Embodiment 3, on the basis of Embodiment 1 or 2, as Figure 11 shown, The sealing sleeve housing 8 further includes ventilation grooves 802 opened at partial positions on the top plate and both side plates of the sealing housing 801. The edges of the ventilation grooves 802 are aligned with the edges of the rear mold 3. A pressure guiding frame body 803 is fixedly connected to the outside of the sealing housing 801 corresponding to the positions of the ventilation grooves 802. Negative pressure transmission pipes 804 are fixedly connected to the top and both side positions of the pressure guiding frame body 803, and the negative pressure transmission pipes 804 are all fixedly connected to a negative pressure vacuum pump.

[0035] During the reciprocating motion of the front mold 4, the negative pressure vacuum pump transmits the negative pressure to the ventilation groove 802 through the negative pressure transmission tube 804. The position of the ventilation groove 802 covers the upper part of the rear mold 3 and the front mold 4 and the upper part of the left and right sides. The negative pressure can extract the air between the front mold 4 and the rear mold 3, and at the same time, it can exert a certain suction force on the liquid PP between the rear mold 3 and the front mold 4, overcome the movement trend of the liquid PP to flow under the rear mold 3 and the front mold 4, and make the liquid PP as close as possible to the middle of the rear mold 3 and the front mold 4. When the front mold 4 is close to the rear mold 3, the liquid PP can be pressed evenly to ensure that the shape of the buried box meets the requirements. At the same time, the discharge of gas can further avoid the occurrence of bubbles in the buried box.

[0036] It should be noted that the negative pressure vacuum pump is not the only tool that can provide negative pressure. Its main function is to provide negative pressure to discharge the gas between the rear mold 3 and the front mold 4. This idea is a common practice of technicians in this field and belongs to the prior art. It is not shown in the figure and is not a further limitation of the solution.

[0037] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. An injection molding machine for producing an underground box, comprising a workbench, an injection molding pipe, a rear mold and a front mold, one end of the injection molding pipe is connected to a screw drive assembly, the screw drive assembly drives the injection molding pipe to rotate and move axially, one side of the front mold is connected to a hydraulic transmission assembly, the hydraulic transmission assembly drives the front mold to move closer to or away from the rear mold, characterized in that: A front mold transmission assembly is connected between the hydraulic transmission assembly and the front mold; the front mold transmission assembly includes a transmission rod fixedly connected to the output shaft of the hydraulic transmission assembly, the end of the transmission rod has a groove, and an electromagnet is fixedly connected in the groove, one side of the front mold is fixedly connected to a flange, one side of the flange is fixedly connected to a moving rod, the moving rod is slidably inserted in the groove at the end of the transmission rod, and the end of the moving rod is fixedly connected to a force-bearing magnet, the force-bearing magnet is acted upon by the magnetic force of the electromagnet, the electromagnet is connected to a frequency converter and the frequency of the change of the magnetic pole of the electromagnet is changed by changing the frequency of the alternating current through the frequency converter; a sealing shell is fixedly connected to the outer side of the rear mold, the sealing shell includes a sealing shell as a main body, the front mold slides in the sealing shell, and the sealing shell forms a closed space between the rear mold and the front mold.

2. The injection molding machine for producing an underground box according to claim 1, characterized in that: One end of the transmission rod is fixedly connected to a cylinder, a piston is slidably connected to the cylinder, one side of the piston is fixedly connected to a connecting rod, the connecting rod is slidably inserted on the side plate of the cylinder and one end is fixedly connected to a flange, both side plates of the cylinder are penetrated and fixedly connected with an air release pipe, an air release groove is opened on the air release pipe, the air release groove is in the shape of a paper clip and the two ends of the air release groove are respectively connected to the internal cavity and the outside of the cylinder.

3. The injection molding machine for producing an underground box according to claim 2, characterized in that: A plurality of semiconductor cooling sheets are embedded and fixedly connected to the piston, and the semiconductor cooling sheets are electrically connected to the frequency converter.

4. The injection molding machine for producing an underground box according to claim 3, characterized in that: The two side plates of the piston and the inner walls of the two side plates of the cylinder are fixedly connected with heat-conducting metal sheets, and the heat-conducting metal sheets correspond to the positions of the semiconductor refrigeration sheets. One side of the heat-conducting metal sheets is fixedly connected with a plurality of V-shaped heat-conducting sheets, and connecting sheets are fixedly connected between the V-shaped heat-conducting sheets.

5. The injection molding machine for producing an underground box according to claim 4, characterized in that: The sealing shell also includes ventilation grooves opened on the top plate and part of the two side plates of the sealing shell, the edges of the ventilation grooves are aligned with the edges of the rear mold, and a pressure-conducting frame is fixedly connected to the position of the ventilation groove on the outside of the sealing shell, and negative pressure conduction pipes are fixedly connected to the top and two side positions of the pressure-conducting frame, and the negative pressure conduction pipes are fixedly connected to the negative pressure vacuum pump.

6. An injection molding machine for producing an underground box according to claim 1 or 5, characterized in that: The injection molding pipeline includes an injection molding shell as an external shell and an injection molding screw in the injection molding shell, the end of the injection molding screw is fixedly connected to a hydraulic oil transmission cylinder, the circumferential side of the hydraulic oil transmission cylinder is fixedly connected to an expansion bladder, both ends of the expansion bladder are fixedly connected to connecting rings, the hydraulic oil transmission cylinder is provided with a groove near the injection molding screw, and the hydraulic oil in the hydraulic oil transmission cylinder can enter the expansion bladder through the groove, the hydraulic oil transmission cylinder is slidably connected with a pressing plate, the side plate of the hydraulic oil transmission cylinder is fixedly installed with a stop rod, the end of the stop rod corresponds to the edge of the groove of the hydraulic oil transmission cylinder, when the pressing plate contacts the stop rod, the position of the pressing plate has not passed through the groove of the hydraulic oil transmission cylinder, the outer side of the injection molding shell is fixedly connected to a sealing ring near the injection nozzle, the sealing ring is fixedly connected with an oil pipe, the outer side of the oil pipe is fixedly installed with a fixed block, the fixed block is fixedly connected with an injection pipe on the side facing the hydraulic oil transmission cylinder, and the injection pipe and the oil pipe are fixedly connected and communicated with each other.

7. The injection molding machine for producing an underground box according to claim 6, characterized in that: A first connecting pipe is fixedly connected through the center of the pressing plate, a fixing ring is fixedly connected in the first connecting pipe, a first blocking block is fixedly connected to one side of the fixing ring through a spring, the first blocking block is covered at the port of the first connecting pipe through the elastic tension of the spring, the oil pipe is connected to the hydraulic pump, a fixing frame is fixedly connected in the oil pipe, a fixing frame is fixedly connected in the injection pipe, a second blocking block is fixedly connected to one side of the fixing frame through a spring, the end of the injection pipe is reduced in diameter inwardly, and the second blocking block is slidably connected to A push rod is fixedly connected to the inner wall of the side plate of the hydraulic oil conducting cylinder, which is connected to the reduced diameter end of the injection pipe. When the injection pipe contacts the first connecting pipe, the end of the injection pipe is sleeved outside the first connecting pipe, and as the pressing plate and the first connecting pipe slide toward the push rod, the push rod will contact the first blocking block, and then the spring on the first blocking block will be stretched, the first blocking block will contact the second blocking block in the injection pipe, and the second blocking block will slide from the end of the injection pipe into the injection pipe, so that the injection pipe and the first blocking block are connected to each other, and the diameter of the injection pipe is the same as that of the first connecting pipe.

8. The injection molding machine for producing underground boxes according to claim 7, characterized in that: The fixed block and the sealing ring are jointly penetrated and fixedly connected with a hydraulic transmission pipe, and the end of the hydraulic transmission pipe extends from the sealing ring to the outside and is connected to the hydraulic pump. A simple hydraulic telescopic rod is fixedly connected to one side of the fixed block, one of the connecting rings is fixedly installed on the end of the hydraulic oil transmission cylinder close to the injection screw, and the other connecting ring is slidably sleeved outside the hydraulic oil transmission cylinder.

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