Precise plunger screw head

Abstract

The utility model relates to a precise plunger screw head which is fixedly installed at the front end of a screw, the screw is coaxially arranged in a material conveying channel of a material pipe, an injection assembly is arranged at the front end of the material pipe, a plunger sealing part is arranged at the front end of the plunger screw head, and a sealing part is arranged at the front end of the plunger sealing part. And a plunger sealing channel matched with the plunger sealing part in a grinding manner is arranged in the injection assembly. The plunger structure is ingeniously integrated into the screw, the integration degree is high, original equipment can be transformed, new equipment does not need to be purchased, and therefore repeated investment is saved, and after the precise plunger screw head is adopted, the injection pressure can be increased, the injection weight can be reduced, the phenomena of plastic carbonization and degradation can be reduced, the quality can be improved, and the production cost can be reduced. And the purpose of precise injection molding is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of injection molding, in particular to a precision plunger screw head. Background Art

[0002] Injection molding is an important part of modern industry. With the continuous improvement of product refinement, the requirements for injection molding precision are also getting higher and higher. In order to achieve precision injection molding, the common practice on the market is to use Sodick's plunger screw, which has a structure like Figure 1 As shown, the machine mainly consists of two parts: a screw and a plunger, which are arranged in a V-shape. The screw melts and pressurizes the material and then transports it to the plunger cavity. The injection volume is then controlled by controlling the movement distance of the piston in the plunger. However, the V-shaped plunger screw has a large structure and requires a lot of space for installation. The purchase of a new machine is very expensive, and replacing the V-shaped injection unit is also expensive. Because the raw material is diverted from the top to the plunger tube, the plastic cannot be first in, first out. The plastic at the front end of the plunger rod stays and carbonizes, producing black spots and yellowing. In addition, the old equipment cannot use the V-shaped injection mechanism, and purchasing a new one will result in repeated investment.

[0003] Therefore, this field urgently needs a product with higher integration and greater injection pressure. Utility Model Content

[0004] The purpose of the present invention is to provide a precision plunger screw head in order to overcome the defects of the prior art.

[0005] In order to achieve the purpose of the present invention, the present application provides the following technical solutions.

[0006] In the first aspect, the present application provides a precision plunger screw head, the precision plunger screw head is fixedly mounted on the front end of the screw, the screw is coaxially arranged in the feed channel of the material pipe, the front end of the material pipe is provided with an injection assembly, characterized in that the front end of the plunger screw head is provided with a plunger sealing portion, and the injection assembly is provided with a plunger sealing channel that is ground with the plunger sealing portion. The present application fixes the injection assembly at the front end of the material pipe. As the material enters the injection assembly and gradually fills the injection assembly, the material continues to be fed, and the material will push the screw as a whole to move backward. At this time, the screw is pushed forward by an external force, so that the plunger sealing portion enters the plunger channel. Since the plunger channel and the plunger sealing portion are ground (that is, the tolerance between the two is very small, when the two slide relative to each other, the material cannot leak from the gap between the two), at this time, the injection assembly and the plunger screw head form a cavity and piston structure. The injection amount of the material can be controlled by controlling the forward distance of the plunger screw head, thereby achieving the purpose of precision injection molding. Moreover, the present application does not need to set up an additional plunger structure like the prior art, and the overall volume is roughly the same as that of the existing common screw.

[0007] In one embodiment of the first aspect, a weight-reducing portion is coaxially provided on the top of the plunger sealing portion, the weight-reducing portion is cylindrical, and the outer diameter of the weight-reducing portion is smaller than the outer diameter of the plunger sealing portion. As is well known, in the field of injection molding screws, the cross-sectional area of the screw is inversely proportional to the injection pressure, and the cross-sectional area of the screw is proportional to the injection weight. In the present application, there are two purposes for setting the weight-reducing portion. The first is to reduce the weight of the injection molding to achieve the purpose of lightweighting, reduce the residence time of the material in the material pipe, and reduce the occurrence of carbonization. The purpose of setting the plunger sealing portion is first to fine-tune the sealant, and second to increase the injection pressure.

[0008] In one embodiment of the first aspect, a ratio of an outer diameter of the weight-reducing portion to an outer diameter of the plunger sealing portion is 0.1 to 0.9:1.

[0009] In one embodiment of the first aspect, the ratio of the outer diameter of the plunger seal to the outer diameter of the screw is 0.1 to 0.9:1. The diameter of the plunger seal is preferably from 1D to 100D, more preferably from 1D to 22D. Of course, the diameter of the plunger seal must be smaller than the diameter of the screw to achieve the function of reducing weight and increasing pressure.

[0010] In one embodiment of the first aspect, a guide portion, a sealing portion, and a guide groove portion are sequentially provided between the connecting thread of the plunger screw head and the plunger sealing portion. A pion is fixed to the outside of the guide portion, and a check ring is sleeved on the outside of the sealing portion. The outer diameter of the check ring is ground to the inner diameter of the feed passage of the feed pipe. The pion, check ring, and guide groove portion are common structures of existing screws. This is a plunger screw head form used in this application. The pion and check ring are formed, and the check ring and pion can form a sealing surface when they abut, forming a sealing structure.

[0011] In one embodiment of the first aspect, the check ring includes any one of a fork-type check ring and a ring-type check ring, wherein the fork-type check ring is more suitable for scenarios with higher melting speeds.

[0012] In one embodiment of the first aspect, the plunger screw head includes a plunger unit, a conjoined check ring and a marble, the front end of the plunger unit is provided with a plunger sealing portion, the rear end of the plunger unit is provided with a mounting cavity, the front end of the mounting cavity is provided with a plurality of second material transfer channels that pass through inside and outside, and the inner wall of the mounting cavity is provided with an internal thread; the outer wall of the front end of the conjoined check ring is provided with an external thread that matches the internal thread, and is fixedly installed at the rear end of the plunger unit; the axis center of the front end of the conjoined check ring is provided with a receiving cavity, the inner wall of the rear end of the receiving cavity is spherical, and the inner wall of the rear end is provided with a first material transfer channel that passes through inside and outside, the inner diameter of the middle part of the receiving cavity is constant, and the diameter of the opening of the front end of the receiving cavity becomes larger, the marble is placed in the receiving cavity, and the diameter of the marble is the same as the diameter of the inner wall of the rear end of the receiving cavity; the rear end of the conjoined check ring is provided with a connecting screw thread, and is fixed to the front end axis center of the screw through the connecting screw thread. This is the second form of the plunger screw head of the present application, which uses the forward and backward movement of the marble to achieve the switching between sealing and feeding.

[0013] In one embodiment of the first aspect, the injection assembly includes a plunger cylinder and a nozzle, a plunger sealing channel is provided at the axis of the plunger cylinder, the plunger cylinder is fixedly mounted at the front end of the material tube, and the nozzle is fixedly mounted at the front end of the plunger cylinder.

[0014] Compared with the prior art, the beneficial effects of the present invention are:

[0015] (1) The plunger structure is cleverly integrated into the screw, with a high degree of integration, and the volume and weight of the plunger screw are greatly reduced;

[0016] (2) It is suitable for injection molding with different metering, and by controlling the stroke of the plunger screw head, the extrusion amount of the material is controlled to achieve the purpose of precision injection molding;

[0017] (3) It can increase the injection pressure of the material; at the same time, it can reduce the residence time of the material in the material pipe and reduce the occurrence of carbonization. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a general schematic diagram of a plunger screw of Sodick in the prior art;

[0019] Figure 2 This is a schematic diagram of the overall assembly of the precision screw head assembly onto the screw;

[0020] Figure 3 Schematic diagram of the structure of the plunger screw head assembly in Example 1;

[0021] Figure 4 This is a partial enlarged schematic diagram of the plunger screw head during glue injection;

[0022] Figure 5This is a partial enlarged schematic diagram of the screw head assembly at the beginning of injection molding;

[0023] Figure 6 This is a partial enlarged schematic diagram of the screw head assembly when the screw continues to push forward;

[0024] Figure 7 This is a partial enlarged schematic diagram of the screw head assembly when the screw restarts to feed glue;

[0025] Figure 8 It is a structural diagram of the plunger cylinder;

[0026] Figure 9 Schematic diagram of the overall structure of the plunger screw head in Example 2;

[0027] Figure 10 for Figure 3 Schematic diagram of the structure of the middle plunger unit;

[0028] Figure 11 for Figure 3 Schematic diagram of the structure of the middle-connected check ring;

[0029] Figure 12 This is a schematic diagram of the structure of the plunger screw head when it is sealed with glue in Example 2;

[0030] Figure 13 It is a structural diagram of the plunger screw head and the plunger cylinder when sealed with glue.

[0031] In the accompanying drawings, 1 is a material pipe, 11 is a feed port, 2 is a screw, 3 is a plunger cylinder, 31 is a connecting channel, 32 is a plunger sealing channel, 33 is an installation channel, 4 is a plunger screw head, 41 is a weight reduction part, 42 is a plunger sealing part, 43 is a connecting part, 431 is a first feed channel, 432 is a mounting cavity, 433 is an internal thread, 44 is a connected check ring, 441 is a second feed channel, 442 is a connecting thread, 443 is an accommodating cavity, 444 is an external thread, 45 is a marble, 46 is a guide groove part, 47 is a sealing part, 48 is a guide part, 49 is a connecting thread, 5 is a nozzle, 6 is a check ring, and 7 is a meson. DETAILED DESCRIPTION

[0032] Unless otherwise defined, technical or scientific terms used in this specification and claims shall have the ordinary meanings understood by persons having ordinary skill in the art to which this invention belongs. All numerical values listed herein, from the lowest value to the highest value, refer to all numerical values obtained by incrementing the lowest value to the highest value by one unit when the difference between the lowest value and the highest value is two units or more.

[0033] The following describes specific embodiments of the present invention. It should be noted that, in the context of describing these embodiments, for the sake of brevity and clarity, this specification does not exhaustively describe all features of the actual embodiments. Those skilled in the art may modify and replace the embodiments of the present invention without departing from the spirit and scope of the present invention, and the resulting embodiments are also within the scope of protection of the present invention.

[0034] Example

[0035] The following is a detailed description of an embodiment of the present invention. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process. However, the protection scope of the present invention is not limited to the following embodiment.

[0036] Example 1

[0037] A precision screw head assembly, after being assembled on the injection molding machine, has the following structure Figure 2 The precision screw head assembly includes a plunger screw head 4 and a plunger cylinder 3, wherein the plunger cylinder 3 is fixedly connected to the top of the material pipe 1 of the injection molding machine, a nozzle 5 is fixed to the front end of the plunger cylinder 3, and the plunger screw head 4 is fixedly installed on the top of the screw 2. A feed port 11 is provided on the material pipe 1.

[0038] The structure of the plunger screw head group is as follows Figure 3 As shown, in this embodiment, the so-called plunger screw head assembly refers to the name after the plunger screw head 4 is assembled into a whole with the check ring 6 and the meson 7. Among them, the plunger screw head 4 is an integrated structure, which includes a weight reduction portion 41, a plunger sealing portion 42, a guide groove portion 46, a sealing portion 47, a guide portion 48 and a connecting screw 49 from the head to the back, wherein the connecting screw 49 is fixed at the front end center of the screw 2, and the plunger screw head 4 and the screw 2 are fixed by a thread. The diameter of the plunger sealing portion 42 is smaller than the diameter of the screw 2, which has the effect of reducing weight and increasing pressure. At the same time, the diameter of the weight reduction portion 41 is smaller than the diameter of the plunger sealing portion 42, which further has the effect of reducing weight and increasing pressure. The meson 7 is fixed on the outside of the guide portion 48, and the two are fixed by a threaded connection. Four guide grooves are opened on the periphery of the guide groove portion 46 and are glued. The check ring 6 is sleeved on the outside of the sealing portion 47, and the axial length of the sealing portion 47 is greater than the axial length of the check ring 6, that is, the relative position of the check ring 6 and the plunger screw head 4 is such that the front end face of the check ring 6 abuts against the tail end face of the guide groove portion 46, and the rear end face of the check ring 6 abuts against the front end face of the meson 7. The check ring can be a ring-type check ring or a fork-type check ring, both of which are existing technologies. The outer diameter of the check ring 6 is ground into the inner wall of the material pipe 1, as shown in FIG. Figures 4 to 7 shown.

[0039] The structure of the plunger cylinder 3 is as follows Figure 8 As shown, its structure is similar to the flange in a conventional screw 2, secured to the front end of the material pipe 1 by several bolts. A through-channel is provided at the axis of the plunger cylinder 3. From the front end to the rear end, it comprises a mounting channel 33, a plunger sealing channel 32, and a connecting channel 31. The inner diameter of the connecting channel 31 is identical to that of the material pipe 1, and they seamlessly intersect. The inner diameter of the plunger sealing channel 32 and the outer diameter of the plunger sealing portion 42 are precision-matched (i.e., the tolerance between the two is less than 0.01 mm, but relative sliding between them is possible). The axial length of the plunger sealing channel 32 is greater than that of the plunger sealing portion 42. The inner wall of the mounting channel 33 is threaded, and the nozzle 5 is fixedly mounted within the mounting channel 33. When the plunger sealing portion 42 begins to insert into the plunger sealing channel 32, the material is intercepted by the plunger sealing portion 42, thus forming a seal. At this point, by controlling the distance that the plunger sealing portion 42 advances, the volume of material ejected from the nozzle 5 can be controlled, achieving the desired effect of precision injection molding.

[0040] The entire working process is as follows:

[0041] During injection, as the screw 2 rotates, the molten material flows forward. At this time, the check ring 6 is located at the front end, that is, the front end of the check ring 6 abuts against the tail end of the guide groove 46, and the plunger sealing portion 42 is not inserted into the plunger sealing channel 32. Figure 4 As shown in the figure, the material flows along the following path: gap between screw 2 and the inner wall of pipe 1 → gap between pion 7 and the inner wall of pipe 1 → gap between the inner wall of check ring 6 and the outer wall of sealing portion 47 → guide groove → passage of plunger cylinder 3 → passage of nozzle 5. Because the mold is in contact with nozzle 5, the cold glue port in the mold prevents material from flowing out of the front end of nozzle 5. Consequently, the material is gradually stored in the passage of nozzle 5. As the stored material fills the passages of nozzle 5 and plunger cylinder 3, the volume of the material in the metering chamber gradually increases as feeding continues, generating a reverse thrust that causes the screw and plunger screw head 4 to gradually move backward.

[0042] When the injection molding starts, the outlet at the front end of the nozzle 5 is opened first, and then the driving device is used to push the screw 2 forward. At this time, the screw 2, the entire plunger screw head 4 and the meson 7 will move forward. Since the check ring 6 is only sleeved on the outside of the sealing portion 47 and is not fixed, the check ring 6 will not move forward at this time until the front end of the meson 7 on the plunger screw head 4 abuts against the rear end of the check ring 6. Figure 5 In this way, the check ring 6 and the meson 7 cut off the flow channel of the molten material, that is, the new material cannot flow forward, and the material originally stored in the nozzle 5 and the plunger cylinder 3 cannot flow backward, which has a sealing effect.

[0043] The driving device drives the screw to continue to move forward. At this time, the screw 2, the plunger screw head 4, the check ring 6, and the meson 7 will move forward together until the plunger sealing portion 42 enters the plunger sealing channel 32. Figure 6 As shown in the figure, due to the close tolerance between the plunger seal 42 and the plunger seal passage 32, a structure similar to that of a syringe and a piston is formed. As the screw 2 continues to advance, the plunger seal 42 pushes the material forward, ejecting it from the nozzle. Because the diameter of the plunger seal passage 32 is fixed, the injection volume can be precisely controlled by controlling the advancement length of the plunger seal 42 (i.e., the screw stroke).

[0044] When the injection molding is completed, the melt driving device starts to rotate, and the material is pushed from the discharge port to the metering chamber by the thrust generated by the screw edge angle. When the material is pushed to the tail end of the check ring 6, the material pushes the check ring 6 to move forward until the front end of the check ring 6 abuts against the tail end of the guide groove 46. In this way, the flow channel of the molten material is reopened. Figure 7 As the volume of the material in the metering chamber does not increase and the material cannot flow out from the front hole of the nozzle 5, the material will generate a reverse thrust, pushing the plunger screw assembly to continue moving backward until the plunger sealing portion 42 is completely pulled out of the plunger sealing channel 32, and then it returns to the state shown in FIG. Figure 4 In the state shown, you can continue with the next injection.

[0045] Example 2

[0046] The material pipe, screw, plunger cylinder and nozzle similar to those in Example 1 are used, except that a different form of plunger screw head is used, as follows.

[0047] In this embodiment, the structure of the plunger screw head 4 is as follows Figures 9 to 13As shown, it mainly consists of two detachable parts. The front part is the plunger unit, which includes a weight-reducing part 41, a plunger sealing part 42, and a connecting part 43 in sequence. These three parts form an integrated structure. A mounting cavity 432 is provided at the axis of the rear end of the connecting part 43. The inner wall of the rear end of the mounting cavity 432 is provided with an internal thread 433. The front end of the mounting cavity 432 is provided with a first feed channel 431 that runs through the inside and outside. The rear part of the plunger screw head 4 is a conjoined check ring 44. A accommodating cavity 443 is provided at the axis of the front end of the conjoined check ring 44. The inner wall of the accommodating cavity 443 at the rear end is spherical, and the inner wall of the rear end is provided with a second feed channel 441 that runs through the inside and outside. The diameter of the opening of the accommodating cavity 443 becomes larger at the front end. The outer wall of the conjoined check ring 44 is provided with an external thread 444 at the front end. The external thread 444 engages with the internal thread 433 at the axis of the connecting part 43, thereby fixing the plunger screw head 4 into a whole from front to back. The outer diameter of the joint check ring 44 and the connecting portion 43 is ground to the inner diameter of the material tube 1. A connecting thread 442 is provided on the outer wall of the rear end of the check ring 44, through which the entire plunger screw head 4 is fixed to the front end of the screw 2. A marble 45 is located within the accommodating chamber 443. The diameter of the marble 45 is the same as the diameter of the inner wall at the rear end of the accommodating chamber 443. The marble 45 can roll back and forth within the accommodating chamber 443. When the marble 45 contacts the sidewall of the rear end of the accommodating chamber 443, it blocks the entire second feed channel 441, acting as a sealant. When the marble 45 is separated from the rear end of the accommodating chamber 443, the material can pass through the second feed channel 441, the accommodating chamber 443, the mounting chamber 432, and the first feed channel 431 in sequence, ultimately reaching the plunger cylinder 3.

[0048] The specific process is as follows:

[0049] When feeding glue, the material enters the material pipe 1 from the feed port 11. Under the transportation of the screw 2, the material melts into a colloidal state and moves forward from the rear end of the material pipe 1. When it reaches the integrated check ring 44 of the plunger screw head 4, since the integrated check ring 44 and the inner wall of the material pipe 1 are in a grinding state, the material can only enter from the second feed channel 441, and then pass through the accommodating cavity 443, the installation cavity 432, the first feed channel 431, and the plunger cylinder 3 in turn, and finally reach the nozzle 5. The nozzle 5 is controlled not to discharge the material, and the material is gradually stored in the channel of the nozzle 5. After the stored material fills the channels of the nozzle 5 and the plunger cylinder 3, when feeding continues, the screw 2 and the plunger screw head 4 will gradually retreat.

[0050] When starting injection molding, first open the outlet at the front end of the nozzle 5, then push the screw 2 forward, and the entire plunger screw head 4 will move forward together. Due to the existence of inertia, the forward speed of the accommodating chamber 443 must be greater than the marble 45, so the marble 45 will gradually retreat relative to the accommodating chamber 443 until it abuts against the inner wall of the rear end of the accommodating chamber 443. In this way, the marble 45 will completely block all the second feed channels 441, forming a sealed state, as shown in FIG. Figure 12 As shown, new material cannot flow forward, and the material originally stored in the nozzle 5 and the plunger cylinder 3 cannot flow backward.

[0051] Continue to push the screw 2 forward until the plunger sealing portion 42 begins to enter the plunger sealing channel 32. Figure 13 As shown in the figure, due to the close tolerance between the plunger seal 42 and the plunger sealing channel 32, a structure similar to that of a syringe and a piston is formed. As the screw 2 continues to advance, the plunger seal 42 pushes the material forward, ejecting it from the nozzle. Because the diameter of the plunger sealing channel 32 is fixed, the injection volume of the material can be precisely controlled by simply controlling the advancement length of the plunger seal 42 (i.e., the stroke of the screw 2).

[0052] When the injection molding is completed, the control screw 2 moves backward as a whole, the marble 45 first disengages from the tail end of the accommodating cavity 443, the second feed channel 441 is reopened, and new material can be injected forward; then the plunger sealing part 42 also disengages from the plunger sealing channel 32, and the material can enter the plunger cylinder 3 and the nozzle 5.

[0053] The above description of the embodiments is intended to facilitate understanding and application of the present application by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without expending any creative effort. Therefore, the present application is not limited to the embodiments described herein, and improvements and modifications made by those skilled in the art based on the disclosure of this application without departing from the scope and spirit of this application are within the scope of this application.

Claims

1. A precision plunger screw head, wherein the precision plunger screw head is fixedly mounted on the front end of the screw, the screw is coaxially arranged in the feeding channel of the material pipe, and the front end of the material pipe is provided with an injection assembly, characterized in that: A plunger sealing portion is provided at the front end of the plunger screw head, and a plunger sealing channel which is ground to match the plunger sealing portion is provided in the injection assembly.

2. The precision plunger screw head according to claim 1, characterized in that: A weight-reducing portion is coaxially provided on the top of the plunger sealing portion. The weight-reducing portion is cylindrical, and the outer diameter of the weight-reducing portion is smaller than the outer diameter of the plunger sealing portion.

3. The precision plunger screw head according to claim 2, characterized in that: The ratio of the outer diameter of the weight-reducing portion to the outer diameter of the plunger sealing portion is 0.1 to 0.9:

1.

4. The precision plunger screw head according to claim 1, characterized in that: The ratio of the outer diameter of the plunger sealing portion to the outer diameter of the screw is 0.1 to 0.9:

1.

5. The precision plunger screw head according to claim 1, characterized in that: A guide portion, a sealing portion and a guide groove portion are sequentially arranged between the connecting thread of the plunger screw head and the plunger sealing portion. A pion is fixed on the outside of the guide portion. A check ring is sleeved on the outside of the sealing portion. The outer diameter of the check ring is ground into the inner diameter of the material delivery channel of the material pipe.

6. The precision plunger screw head according to claim 5, characterized in that: The check ring includes any one of a fork-type check ring and a ring-type check ring.

7. The precision plunger screw head according to claim 1, characterized in that: The plunger screw head includes a plunger unit, a connected check ring and a marble. The front end of the plunger unit is provided with a plunger sealing part, and the tail end of the plunger unit is provided with a mounting cavity. The front end of the mounting cavity is provided with multiple second feeding channels that pass through inside and outside, and the inner wall of the mounting cavity is provided with an internal thread; the outer wall of the front end of the connected check ring is provided with an external thread matching the internal thread, and is fixedly installed at the tail end of the plunger unit; an accommodating cavity is provided at the axis center of the front end of the connected check ring, the inner wall of the tail end of the accommodating cavity is spherical, and the inner wall of the tail end is provided with a first feeding channel that passes through inside and outside, the inner diameter of the middle part of the accommodating cavity is constant, and the diameter of the opening of the front end of the accommodating cavity becomes larger, the marble is placed in the accommodating cavity, and the diameter of the marble is the same as the diameter of the inner wall of the tail end of the accommodating cavity; the tail end of the connected check ring is provided with a connecting screw thread, and is fixed to the front end axis center of the screw through the connecting screw thread.

8. The precision plunger screw head according to claim 1, characterized in that: The injection assembly includes a plunger cylinder and a nozzle. A plunger sealing channel is provided at the axis of the plunger cylinder. The plunger cylinder is fixedly installed at the front end of the material tube, and the nozzle is fixedly installed at the front end of the plunger cylinder.

Images