An injection molding machine for producing engineering plastic parts

Abstract

The present application discloses an injection molding machine for producing engineering plastic parts. A rotatable nozzle rod is arranged on the nozzle of the injection molding machine, so that when the nozzle rod is inserted into the gate, it drives the extrusion rod to move forward synchronously and is guided by the toggle groove to drive the nozzle rod to rotate, so that the guide hole in the nozzle rod is connected with the discharge hole on the nozzle and the feed hole in the gate, forming an injection flow channel from top to bottom. When the nozzle drives the nozzle rod to separate from the gate, the influence of the toggle groove on the extrusion rod will gradually decrease. At this time, the gravity ball will drive the entire nozzle rod to rotate, so that the guide hole is separated from the discharge hole and the feed hole. At this time, the discharge hole will be blocked, eliminating the influence of the subsequent molten plastic in the nozzle on the molten plastic in the nozzle rod, and the connecting port I on the guide hole will be twisted at the connection with the feed hole, and the connection point of the continuously solidified plastic in the feed hole and the molten material in the guide hole will be cut off by the torsional force, thereby reducing the formation of wire drawing.

Description

Technical Field

[0001] The present application relates to the technical field of plastic processing, and in particular to an injection molding machine for producing engineering plastic parts. Background Art

[0002] Injection molding machines are generally used for the production of engineering plastic parts. The granular plastic is melted into liquid by the injection molding machine, and the nozzle of the injection molding machine is inserted into the gate of the mold through a mobile device. The molten plastic is then pressed into the mold through the nozzle on the injection molding machine by pressure, and injection molding is performed. After the mold is cooled, the finished plastic part is obtained.

[0003] In this process, taking a horizontal injection molding machine as an example, the nozzle that has completed the injection molding will leave the gate again driven by the moving device. At this time, the injection molding machine will remove the pressure on the molten plastic. Since the molten material cooled by the internal cooling system of the mold at the gate gradually solidifies, and the molten material in the nozzle remains molten, if the nozzle is directly pulled out of the gate, the solidified plastic can easily pull a large amount of the molten plastic in the nozzle out of the nozzle, and the molten material in the inner cavity of the injection molding machine will also tend to detach from the nozzle opening, causing wire drawing to form at the nozzle, resulting in waste of molten plastic. After solidification, this wire drawing will hinder the nozzle from being inserted into the gate again, affecting subsequent processing. Summary of the invention

[0004] The present application proposes an injection molding machine for producing engineering plastic parts, which has the advantages that when the extrusion rod moves forward, it is guided by the toggle groove to drive the nozzle rod to rotate, when the extrusion rod retreats, it gradually loses the restriction of the toggle groove and drives the nozzle rod to rotate under the drive of the gravity ball, when the nozzle rod is inserted into the gate, the nozzle rod rotates to make the injection flow channel pass through, when the nozzle rod is inserted into the gate, the gravity ball pushes the piston to input the retained molten plastic into the guide hole, the gravity ball pushes the piston to make the valve plate close the branch hole to prevent the molten plastic in the guide hole from entering the retention cylinder under the pressure of the injection molding machine, when the nozzle rod leaves the gate, it rotates to disconnect the injection flow channel, and the disconnected injection flow channel prevents the molten plastic in the nozzle from flowing into the guide hole, when the nozzle rod rotates, the residual molten plastic in the guide hole converges to the connection port II at a lower position to prevent the residual molten plastic from flowing out of the connection port I, and when the nozzle rod rotates, the gravity ball pulls the piston to extract the residual molten plastic in the guide hole through the branch hole, so as to solve the problem of drooling and wire drawing of the nozzle of the existing injection molding machine.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical scheme: an injection molding machine for the production of engineering plastic parts, comprising a fixed mold base and a nozzle on one side, a gate is provided at one end of the fixed mold base, a feeding hole is provided at the bottom of the gate, and a toggle groove is provided on the outer side of the fixed mold base located on the gate to limit the rotation direction of the nozzle rod; a liquid collection cavity is provided at one end of the nozzle, and a discharge hole is provided on one side of the liquid collection cavity, a connecting seat is provided on the side of the nozzle facing the fixed mold base, an annular groove is provided on the inner side wall of the connecting seat, a nozzle rod is sleeved in the connecting seat, and an annular extension protrusion is provided on the outer side of the end of the nozzle rod close to the nozzle The extended protrusion is movably sleeved in the annular groove to limit the position of the nozzle rod; a guide hole is opened in the nozzle rod, and the guide hole forms a connection port I near the opening of the gate, and the guide hole forms a connection port II near the opening of the nozzle. The nozzle rod is inserted into the gate, and the connection port I is connected to the feeding hole, and the connection port II is connected to the discharge hole. The guide hole forms a streamlined shape with the connection port I at the bottom and the connection port II at the top, which is used to guide the flow direction of the molten plastic; a fixed seat is provided on the outer side of the nozzle rod, and an L-shaped extrusion rod is provided on the fixed seat. The extrusion rod is inserted into the toggle groove to receive the extrusion of the toggle groove to drive the nozzle rod to rotate.

[0006] Preferably, the toggle groove is semi-annular, the depth of the toggle groove increases uniformly from bottom to top, and the minimum depth of the toggle groove is greater than the minimum depth of the gate.

[0007] Preferably, the distance that one end of the horizontal portion of the extrusion rod inserted into the toggle groove is inserted into the fixed mold seat is greater than the distance that the nozzle rod is inserted into the gate, so that the extrusion rod first contacts the bottom of the toggle groove to drive the advancing nozzle rod to rotate.

[0008] Preferably, a snap-fit ​​plate is provided at the center of the outer top of the nozzle rod, a retention cylinder is provided at the center of the top of the snap-fit ​​plate, a sealing cover is provided at the top opening of the retention cylinder, a piston is provided in the inner cavity of the retention cylinder, a pull rod is provided at the center of the top of the piston for extracting and squeezing out the molten plastic, and an electric heating pipe is provided on the outer side of the retention cylinder for heating the molten plastic in the retention cylinder.

[0009] Preferably, a gravity ball is provided at the top end of the pull rod passing through the cover, and the center of the gravity ball is eccentrically arranged to one side of the circumference where the toggle groove is located, so as to provide power for the nozzle rod to rotate after it is separated from the gate.

[0010] Preferably, a connecting port is provided on the bottom end of the retention cylinder and the snap-fit ​​plate, an inclined branch hole is provided in the nozzle rod, the bottom opening of the branch hole is connected to the guide hole, and the top opening of the branch hole is connected to the connecting port, so as to provide a channel for the molten plastic to enter the retention cylinder, and the bottom end of the branch hole is closer to the connecting port I than the top end, so as to reduce the obstruction encountered when the molten plastic in the retention cylinder flows back to the guide hole.

[0011] Preferably, a spring is provided between the sealing cover and the piston for driving the piston to move in advance.

[0012] Preferably, a vertical valve hole is provided in the nozzle rod, and a valve plate is provided in the valve hole for sealing the branch hole after the molten plastic in the retention cylinder is discharged, the top end of the valve plate passes through the snap-fit ​​plate and the bottom end of the retention cylinder and is fixed to the bottom end of the piston for synchronous movement with the piston, and a valve port is provided at the bottom of the valve plate for providing a flow channel for the molten plastic in the guide hole.

[0013] Preferably, a pressure relief hole is opened in the nozzle rod, one end of the pressure relief hole is connected to the guide hole, and the valve hole passes through the branch hole and the guide hole from top to bottom and is connected to the pressure relief hole, so as to press the molten plastic in the pressure relief hole to the guide hole when the valve plate is pressed down.

[0014] The present application provides an injection molding machine for the production of engineering plastic parts. A rotatable nozzle rod is arranged on the nozzle of the injection molding machine so that when the nozzle rod is inserted into the gate, the extrusion rod is driven to move forward synchronously and is guided by the toggle groove to drive the nozzle rod to rotate, so that the guide hole in the nozzle rod is connected with the discharge hole on the nozzle and the feed hole in the gate, forming an injection flow channel from top to bottom, so that the molten material can quickly pass through the injection flow channel into the mold for injection molding, thereby reducing pressure loss.

[0015] At the same time, when the nozzle drives the nozzle rod to separate from the gate, the influence of the toggle groove on the extrusion rod will gradually decrease. At this time, the gravity ball will drive the entire nozzle rod to rotate, so that the guide hole is separated from the discharge hole and the feed hole. At this time, the discharge hole will be blocked, eliminating the influence of the molten plastic in the subsequent nozzle on the molten plastic in the nozzle rod, and the connecting port Ⅰ on the guide hole will be twisted at the connection with the feed hole, and the connection point between the continuously solidified plastic in the feed hole and the molten material in the guide hole will be cut off by the torsional force, reducing the formation of wire drawing, and at this time, the position of the connecting port Ⅰ gradually rotates to a high position, so that the molten material at the connecting port Ⅰ has a tendency to flow to the low position in the guide hole, further hindering the molten plastic in the guide hole from flowing out of the connecting port Ⅰ.

[0016] At the same time, when the gravity ball drives the entire nozzle rod to rotate, the gravity ball itself will gradually rotate to the lower position, so that the gravity ball pulls the piston downward through the pull rod, so that the piston extracts the molten plastic in the diversion hole through the connecting port and the branch hole into the retention cylinder, thereby guiding the material at the connection port I to flow in the direction of the branch hole, further avoiding the problem of molten material being discharged from the connection port I, and an electric heating pipe is arranged on the outside of the retention cylinder to heat and keep the sucked molten plastic warm, waiting for the next injection to input the molten plastic in the retention cylinder into the diversion hole again. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which constitute a part of the specification, illustrate the embodiments disclosed in the present application and, together with the description, serve to explain the principles disclosed in the present application.

[0018] The present disclosure may be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0019] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0020] Figure 2 This is a schematic diagram of the fixed die base structure of the present invention;

[0021] Figure 3 This is a schematic diagram of the nozzle rod structure position of the present invention;

[0022] Figure 4 This is a schematic diagram of the internal structure distribution of the present invention;

[0023] Figure 5 It is a schematic diagram of the structure of the nozzle and the connecting seat of the present invention;

[0024] Figure 6 This is a schematic diagram of the internal structure of the nozzle rod of the present invention;

[0025] Figure 7 This is a schematic diagram of the internal structure of the retention cylinder of the present invention;

[0026] Figure 8 It is a schematic diagram of the internal injection flow channel distribution of the present invention.

[0027] Among them: 1. Fixed mold base; 2. Gate; 3. Feed hole; 4. Toggle groove; 5. Nozzle; 51. Liquid collection chamber; 52. Discharge hole; 6. Connecting seat; 61. Ring groove; 7. Nozzle rod; 71. Extended protrusion; 8. Guide hole; 81. Connecting port I; 82. Connecting port II; 83. Branch hole; 84. Valve hole; 85. Pressure relief hole; 9. Fixed seat; 91. Extrusion rod; 10. Snap plate; 11. Retention cylinder; 12. Cover; 13. Pull rod; 14. Piston; 15. Spring; 16. Gravity ball; 17. Connecting port; 18. Electric heating pipe; 19. Valve plate; 20. Valve port. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application. Example

[0029] See also Figure 1 to Figure 2 , Figure 8 , an injection molding machine for producing engineering plastic parts, comprising a fixed mold base 1 and a nozzle 5 on one side, a gate 2 is provided at one end of the fixed mold base 1, a feeding hole 3 is provided in the fixed mold base 1, the feeding hole 3 is connected with the gate 2, the feeding hole 3 is located at one end of the gate 2 and the opening is at the bottom of the gate 2, the fixed mold base 1 is located on the outside of the gate 2 and is provided with a toggle groove 4, the toggle groove 4 is semi-annular, by limiting the shape of the toggle groove 4, the extrusion rod 91 entering the toggle groove 4 can rotate up to 180 degrees, so that the extrusion rod 91 can drive the nozzle rod 7 and the retention cylinder 11 to rotate 180 degrees, ensuring that the guide hole 8 can be connected with the discharge hole 52 and the feeding hole 3, ensuring that the retention cylinder 11 can rotate from the lower position of the nozzle rod 7 to the upper position, the toggle groove 4 moves from the bottom to the top, the spacing between the groove bottom and the groove is uniformly increased, and the toggle groove 4 is The minimum spacing value from the bottom of the groove 4 to the groove opening is greater than the spacing value from the bottom of the groove of the gate 2 to the groove opening, so that when the nozzle 5 drives the nozzle rod 7 to insert into the gate 2, the extrusion rod 91 can move synchronously with the nozzle rod 7, so that the horizontal end of the extrusion rod 91 can first contact the bottom of the toggle groove 4 with the shallowest depth. As the nozzle rod 7 drives the extrusion rod 91 to continue to move forward, the extrusion rod 91 can only move from the shallowest depth to the deepest depth along the bottom of the toggle groove 4 in the toggle groove 4, that is, to perform a rotational forward movement with the center line of the nozzle rod 7 as the center of the circle, so that the extrusion rod 91 can drive the nozzle rod 7 to rotate synchronously. When the nozzle 5 drives the nozzle rod 7 to gradually separate from the gate 2, the actions of the extrusion rod 91 and the nozzle rod 7 are opposite to the above actions. It should be noted that at this time, the rotation action of the nozzle rod 7 comes from the rotation of the gravity ball 16 under its own weight.

[0030] See also Figure 1 , Figures 3 to 5 , Figure 8 A liquid collecting chamber 51 is provided at one end of the nozzle 5, and a thread is provided on the wall of the liquid collecting chamber 51 for fixed connection with the barrel of an existing injection molding machine. The barrel will provide pressurized molten plastic to the nozzle 5 and drive the nozzle 5 to perform reciprocating linear motion. A discharge hole 52 is provided on one side of the liquid collecting chamber 51. A connecting seat 6 is fixedly connected to the side of the nozzle 5 facing the fixed mold seat 1 by bolts, and an annular groove 61 is provided on the inner side wall of the connecting seat 6.

[0031] See also Figure 1 , Figure 3 to Figure 4 , Figure 6 , Figure 8 A nozzle rod 7 is arranged between the nozzle 5 and the fixed mold base 1. The side of the nozzle rod 7 close to the nozzle 5 is movably sleeved in the connecting seat 6. The end of the nozzle rod 7 close to the nozzle 5 is fitted with the opposite end of the nozzle 5. An annular extension protrusion 71 is welded on the outer side of the end of the nozzle rod 7 close to the nozzle 5. The extension protrusion 71 is movably sleeved in the annular groove 61, so that the nozzle rod 7 can rotate in the connecting seat 6. At this time, the nozzle 5 will not rotate, and the connecting seat 6 will provide support and limit for the nozzle rod 7. The center of the nozzle rod 7 remains unchanged during rotation. The connection between the nozzle rod 7, the connecting seat 6 and the nozzle 5 is sealed, so that when the nozzle rod 7 rotates, the molten plastic will not leak from the gap.

[0032] See also Figure 4 , Figure 6 , Figure 8 A guide hole 8 is provided in the nozzle rod 7. The opening of the guide hole 8 near the gate 2 forms a connection port Ⅰ81, and the opening of the guide hole 8 near the nozzle 5 forms a connection port Ⅱ82. When the nozzle rod 7 is inserted into the gate 2, the connection port Ⅰ81 is located at the bottom of the end of the nozzle rod 7 near the gate 2, and the connection port Ⅱ82 is located at the top of the end of the nozzle rod 7 near the nozzle 5. The guide hole 8 forms a streamlined shape with the connection port Ⅰ81 at the bottom and the connection port Ⅱ82 at the top. When the nozzle rod 7 is inserted into the gate 2, the connection port Ⅰ81 is connected to the feed hole 3, and the connection port Ⅱ82 is connected to the discharge hole 52 to form an injection flow channel, so that when the molten plastic in the nozzle 5 flows under the pressure provided by the injection molding machine barrel, it can be input into the guide hole 8 through the discharge hole 52, flow downward along the flow channel of the guide hole 8, and be input into the feed hole 3 from the lower connection port Ⅰ81. The flow stroke from top to bottom reduces the pressure loss of the molten material. When the nozzle 5 is brought When the movable nozzle rod 7 is separated from the gate 2, the influence of the toggle groove 4 on the extrusion rod 91 will gradually decrease. At this time, the gravity ball 16 will drive the entire nozzle rod 7 to rotate. At this time, the connection port Ⅰ81 will rotate upward, and the connection port Ⅱ82 will rotate downward, so that the guide hole 8 is separated from the discharge hole 52 and the feed hole 3. At this time, the discharge hole 52 will be blocked by the nozzle rod 7, eliminating the influence of the molten plastic in the subsequent nozzle 5 on the molten plastic in the nozzle rod 7, and the connection port Ⅰ81 on the guide hole 8 will be twisted at the connection with the feed hole 3, and the connection point between the continuously solidified plastic in the feed hole 3 and the molten material in the guide hole 8 will be cut off by the torsional force, reducing the formation of wire drawing, and at this time, the position of the connection port Ⅰ81 gradually rotates to a high position, so that the molten material at the connection port Ⅰ81 has a tendency to flow to the low position in the guide hole 8, further hindering the molten plastic in the guide hole 8 from flowing out of the connection port Ⅰ81.

[0033] See also Figure 1 , Figure 3 to Figure 4 , Figure 6 , Figure 8 The top outer side of the nozzle rod 7 is bolted with a fixing seat 9, and an L-shaped extrusion rod 91 is welded at the center of the fixing seat 9. An arc surface is provided at one end of the extrusion rod 91 that is horizontally inserted into the toggle groove 4, and a rolling ball can also be designed on this end surface to reduce the hard friction between the extrusion rod 91 and the bottom of the toggle groove 4. The distance at which the end of the extrusion rod 91 that is horizontally inserted into the toggle groove 4 is inserted into the fixed mold seat 1 is greater than the distance at which the nozzle rod 7 is inserted into the gate 2, so that when the nozzle head 5 drives the nozzle rod 7 to be inserted into the gate 2, the extrusion rod 91 can move synchronously with the nozzle rod 7, so that the horizontal end of the extrusion rod 91 can first contact the bottom of the toggle groove 4 where the depth is the shallowest.

[0034] See also Figure 1 , Figure 3 to Figure 4 , Figures 7 and 8 The center of the top of the outer side of the nozzle rod 7 is bolted with a snap-fit ​​plate 10, and the top center of the snap-fit ​​plate 10 is fixedly connected with a retention cylinder 11, so that the retention cylinder 11 is fixed to the nozzle rod 7 through the snap-fit ​​plate 10. When the nozzle rod 7 rotates due to the influence of the extrusion rod 91, it can drive the retention cylinder 11 to rotate synchronously. When the gravity ball 16 moves downward due to its own weight, it will transmit the force to the nozzle rod 7 through the retention cylinder 11, driving the nozzle rod 7 to rotate. The top opening of the retention cylinder 11 is fixedly connected with a cover 12 by bolts, and a piston 14 is movably sleeved in the inner cavity of the retention cylinder 11. The top center of the piston 14 is fixedly connected with a pull rod 13, and the outer side of the retention cylinder 11 is fixedly sleeved with an electric heating pipe 18. The molten plastic extracted from the retention cylinder 11 is heated by the electric heating pipe 18 to keep the plastic in a molten state, so as to facilitate the return of these molten plastics to the guide hole 8 during the next injection.

[0035] See also Figure 4 , Figures 7 and 8The pull rod 13 passes through the top of the cover 12 and is fixedly connected with a gravity ball 16. The center of the gravity ball 16 is eccentrically arranged to the circumferential side where the toggle groove 4 is located, so that when the nozzle 5 drives the nozzle rod 7 to gradually separate from the gate 2, the restriction of the toggle groove 4 on the extrusion rod 91 will gradually weaken. In other words, at this time, the restriction on the entire nozzle rod 7 and the gravity ball 16 is also gradually weakened, but the direction in which the extrusion rod 91 can rotate is still limited, which also limits the direction in which the nozzle rod 7 can rotate. At this time, the gravity ball 16 is eccentrically arranged. , so that the gravity ball 16, under its own weight, drives the nozzle rod 7 to rotate in the rotation direction limited by the toggle slot 4 with the center line of the nozzle rod 7 as the center of the circle. At this time, the gravity ball 16 and the retention cylinder 11 will gradually rotate to the lower position of the nozzle rod 7. In this process, the component force of the gravity ball 16 in the direction perpendicular to the horizontal plane will gradually increase, so that the gravity ball 16 gradually pulls the pull rod 13, driving the piston 14 to move in the direction of the cover 12, causing the piston 14 to extract the molten plastic in the guide hole 8 through the connecting port 17 and the branch hole 83. The material enters the retention cylinder 11, and when the nozzle 5 drives the nozzle rod 7 to insert into the gate 2, the extrusion rod 91 can move synchronously with the nozzle rod 7, so that the horizontal end of the extrusion rod 91 can first contact the bottom of the shallowest groove 4. As the nozzle rod 7 drives the extrusion rod 91 to continue to move forward, the extrusion rod 91 can only move from the shallowest depth to the deepest depth in the toggle groove 4 along the bottom of the toggle groove 4, that is, to perform a rotation forward action with the center line of the nozzle rod 7 as the center of the circle, so that the extrusion rod 91 can drive the nozzle 5 to move synchronously with the nozzle rod 7, so that the horizontal end of the extrusion rod 91 can first contact the bottom of the toggle groove 4. The nozzle rod 7 rotates synchronously, and the nozzle rod 7 will drive the storage cylinder 11 and the gravity ball 16 to rotate synchronously, so that the storage cylinder 11 and the gravity ball 16 gradually rotate from the bottom of the nozzle rod 7 to the top of the nozzle rod 7. In this process, the component force of the gravity ball 16 in the direction perpendicular to the horizontal plane will gradually increase, so that the gravity ball 16 gradually pushes the pull rod 13, driving the piston 14 to move in the direction of the connecting port 17, causing the piston 14 to transfer the molten plastic in the storage cylinder 11 back to the guide hole 8 through the connecting port 17 and the branch hole 83.

[0036] See also Figure 7 A connecting port 17 is provided on the bottom end of the retention cylinder 11 and the snap-fit ​​plate 10, and an inclined fork hole 83 is provided in the nozzle rod 7. The bottom opening of the fork hole 83 is connected to the guide hole 8, and the top opening of the fork hole 83 is connected to the connecting port 17. The bottom end of the fork hole 83 is closer to the connecting port Ⅰ81 than the top end, so that the molten plastic pressed out from the retention cylinder 11 to the fork hole 83, when merged into the guide hole 8, has the same flow direction as the molten plastic in the guide hole 8, thereby reducing the problem of impact between the molten plastic merged into the branch fork hole 83 and the molten material in the main branch guide hole 8. Example

[0037] See also Figure 4 , Figures 7 and 8On the basis of the first embodiment, the outer side of the pull rod 13 is wrapped with a spring 15, the bottom end of the spring 15 is fixedly connected to the top end of the piston 14, and the top end of the spring 15 is fixedly connected to the bottom end of the cover 12. When the gravity ball 16 is above the nozzle rod 7, the piston 14 is pressed downward to discharge the molten plastic in the retention cylinder 11. The downwardly moving piston 14 will pull the spring 15 to stretch and store energy. Then, when the gravity ball 16 gradually rotates to the lower position of the nozzle rod 7, the component force of the gravity ball 16 in the direction of the piston 14 continues to decrease. At this time, the stretched spring 15 can pull the piston 14 to move in the direction of the cover 12 in advance, without waiting for the gravity ball 16 to rotate to a certain angle to provide sufficient pulling force to pull the piston 14 to move, so that the piston 14 can be sucked in advance through the fork hole 83 and the connecting port 17 The molten plastic entering the guide hole 8 shortens the retention time of the molten plastic in the guide hole 8, especially when the nozzle rod 7 starts to rotate after leaving the gate 2. This advance movement will further hinder the discharge of the molten plastic at the connection port I81. When the gravity ball 16 rotates to the lower position of the nozzle rod 7, the spring 15 will be compressed and stored. Then, when the gravity ball 16 gradually rotates to the upper position of the nozzle rod 7, the component force of the gravity ball 16 in the direction away from the piston 14 is continuously reduced, so that the compressed spring 15 can push the piston 14 in advance to push the molten plastic in the retention cylinder 11 back into the guide hole 8. At this time, the connection port II82 has not yet been connected to the discharge hole 52, and the pressurized molten plastic has not yet passed through the discharge hole 52 to enter the guide hole 8. At this time, the molten plastic pushed back in advance will enter the guide hole 8 more smoothly. Example

[0038] See also Figure 4 , Figures 6 to 8 On the basis of the first embodiment, a pressure relief hole 85 is opened in the nozzle rod 7, one end of the pressure relief hole 85 is connected to the guide hole 8, and a vertical valve hole 84 is opened in the nozzle rod 7, and the valve hole 84 passes through the branch hole 83 and the guide hole 8 from top to bottom and is connected to the pressure relief hole 85.

[0039] A valve plate 19 is movably sleeved in the valve hole 84. The top of the valve plate 19 penetrates the buckle plate 10 and the bottom of the retention cylinder 11 and is fixed to the bottom of the piston 14 by bolts. A valve port 20 is provided at the bottom of the valve plate 19, so that when the piston 14 moves toward the cover 12 to extract the molten plastic, it can drive the valve plate 19 to move synchronously in the same direction. At this time, since the valve plate 19 closes the bifurcation hole 83, the piston 14 can only perform empty extraction, but the space between the piston 14 and the communication port 17 will continue to increase, and the pressure will continue to decrease. When the valve port 20 moves When the piston 14 moves to the direction of the connecting hole 17 to press out the molten plastic, it can drive the valve plate 19 to move synchronously in the same direction. At this time, the valve port 20 still opens the fork hole 83, and the molten plastic in the retention cylinder 11 can flow out through the fork hole 83. When the valve port 20 leaves the fork hole 83 and the closed part of the valve plate 19 closes the fork hole 83, the molten plastic in the retention cylinder 11 can no longer be discharged. At this time, gravity The ball 16 will not be able to move further, and the valve port 20 is at the position of the guide hole 8, which will not hinder the normal flow of the molten plastic in the guide hole 8. Since the valve plate 19 closes the branch hole 83, the molten plastic in the guide hole 8 cannot rush into the retention cylinder 11 through the branch hole 83 at this time, so that when the branch hole 83 is opened next time, there is still enough space in the retention cylinder 11 to suck the molten plastic remaining in the guide hole 8. When the bottom end of the valve plate 19 contacts and fits with the bottom end of the pressure relief hole 85, the top end of the valve plate 19 closes the branch hole 83. Closed, the valve port 20 of the valve plate 19 opens the guide hole 8. At this time, because the valve plate 19 is in the pressure relief hole 85, the molten plastic in the pressure relief hole 85 can be discharged through the port connecting the pressure relief hole 85 with the guide hole 8, and will not hinder the normal downward pressure of the valve plate 19. At this time, the bottom end of the valve plate 19 is in contact with the bottom end of the pressure relief hole 85, and the pressurized molten plastic passing through the valve port 20 exerts a force on the top and bottom ends of the valve port 20. Therefore, the valve plate 19 will not be displaced due to the pressure of the molten plastic.

Claims

1. An injection molding machine for producing engineering plastic parts, characterized in that: The fixed mold base (1) comprises a nozzle (5) on one side, wherein a gate (2) is provided at one end of the fixed mold base (1), a material delivery hole (3) is provided at the bottom of the gate (2), and a toggle groove (4) is provided on the outer side of the gate (2) of the fixed mold base (1) for limiting the rotation direction of the nozzle rod (7); A liquid collecting chamber (51) is provided at one end of the nozzle (5), a discharge hole (52) is provided at one side of the liquid collecting chamber (51), a connecting seat (6) is provided at the side of the nozzle (5) facing the fixed mold seat (1), an annular groove (61) is provided on the inner side wall of the connecting seat (6), a nozzle rod (7) is sleeved in the connecting seat (6), an annular extension protrusion (71) is provided on the outer side of one end of the nozzle rod (7) close to the nozzle (5), and the extension protrusion (71) is movably sleeved in the annular groove (61) for limiting the position of the nozzle rod (7); The nozzle rod (7) is provided with a guide hole (8), the opening of the guide hole (8) close to the gate (2) forms a connection port I (81), and the opening of the guide hole (8) close to the nozzle (5) forms a connection port II (82), one end of the nozzle rod (7) is inserted into the gate (2), the connection port I (81) is connected to the material feeding hole (3), and the connection port II (82) is connected to the material discharge hole (52), and the guide hole (8) forms a streamlined shape with the connection port I (81) at the bottom and the connection port II (82) at the top, so as to guide the flow direction of the molten plastic; A fixing seat (9) is arranged on the outer side of the nozzle rod (7), and an L-shaped extrusion rod (91) is arranged on the fixing seat (9). The extrusion rod (91) is inserted into the toggle groove (4) and is used to receive the extrusion of the toggle groove (4) to drive the nozzle rod (7) to rotate; A snap-fit ​​plate (10) is provided at the center of the top of the outer side of the nozzle rod (7), a retaining cylinder (11) is provided at the center of the top of the snap-fit ​​plate (10), a sealing cover (12) is provided at the top opening of the retaining cylinder (11), a piston (14) is provided in the inner cavity of the retaining cylinder (11), a pull rod (13) is provided at the center of the top of the piston (14) for extracting and squeezing out molten plastic, and an electric heating tube (18) is provided on the outer side of the retaining cylinder (11) for heating the molten plastic in the retaining cylinder (11); a gravity ball (16) is provided at the top of the pull rod (13) penetrating through the sealing cover (12), the center of the gravity ball (16) is eccentrically arranged to the circumferential side where the toggle groove (4) is located, and is used to provide power for the nozzle rod (7) to rotate after it is separated from the gate (2).

2. The injection molding machine for producing engineering plastic parts according to claim 1, characterized in that: The toggle groove (4) is semi-annular in shape, and the depth of the toggle groove (4) increases evenly from bottom to top, and the minimum depth of the toggle groove (4) is greater than the minimum depth of the gate (2).

3. The injection molding machine for producing engineering plastic parts according to claim 2, characterized in that: The distance at which one end of the horizontal portion of the extrusion rod (91) is inserted into the toggle groove (4) is greater than the distance at which the nozzle rod (7) is inserted into the gate (2), so that the extrusion rod (91) first contacts the bottom of the toggle groove (4) to drive the advancing nozzle rod (7) to rotate.

4. The injection molding machine for producing engineering plastic parts according to claim 3, characterized in that: A communicating port (17) is provided on the bottom end of the storage cylinder (11) and the buckle plate (10), and an inclined fork hole (83) is provided in the nozzle rod (7). The bottom opening of the fork hole (83) is connected to the guide hole (8), and the top opening of the fork hole (83) is connected to the communicating port (17), so as to provide a passage for the molten plastic to enter the storage cylinder (11). The bottom end of the fork hole (83) is closer to the connecting port I (81) than the top end, so as to reduce the obstruction encountered by the molten plastic in the storage cylinder (11) when it flows back to the guide hole (8).

5. The injection molding machine for producing engineering plastic parts according to claim 4, characterized in that: A spring (15) is provided between the sealing cover (12) and the piston (14) for driving the piston (14) to move in advance.

6. The injection molding machine for producing engineering plastic parts according to claim 5, characterized in that: A vertical valve hole (84) is provided in the nozzle rod (7), and a valve plate (19) is provided in the valve hole (84) for sealing the branch hole (83) after the molten plastic in the retention cylinder (11) is discharged. The top end of the valve plate (19) passes through the snap-fit ​​plate (10) and the bottom end of the retention cylinder (11) and is fixed to the bottom end of the piston (14) for synchronous movement with the piston (14). The bottom of the valve plate (19) is provided with a valve port (20) for providing a flow channel for the molten plastic in the guide hole (8).

7. The injection molding machine for producing engineering plastic parts according to claim 6, characterized in that: A pressure relief hole (85) is provided in the nozzle rod (7), one end of the pressure relief hole (85) is connected to the guide hole (8), and the valve hole (84) passes through the branch hole (83) and the guide hole (8) from top to bottom to be connected to the pressure relief hole (85), so as to press the molten plastic in the pressure relief hole (85) toward the guide hole (8) when the valve plate (19) is pressed downward.

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