CN119099104A - Precision plunger screw head - Google Patents

Abstract

The present invention relates to 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, the front end of the material pipe is provided with an injection assembly, the front end of the plunger screw head is provided with a plunger sealing part, and the injection assembly is provided with a plunger sealing channel that is ground with the plunger sealing part. The present invention skillfully integrates the plunger structure into the screw, has a high degree of integration, can be modified on the original equipment, does not need to purchase new equipment, thereby saving repeated investment, and after using the precision injection screw head, can increase the injection pressure, reduce the injection weight, can reduce the carbonization and degradation of plastics, can improve the quality, and achieve the purpose of precision injection molding.

Description

Precision plunger screw head

Technical Field

The invention relates to the technical field of injection molding, in particular to a precision plunger screw head.

Background

Injection molding is an important component part in the modern industry, and along with the continuous improvement of the product refinement degree, the requirement on injection molding precision is also higher and higher. In order to realize precise injection molding, a plunger type screw rod of a sand dick is commonly used in the market at present, the structure of the plunger type screw rod is shown in fig. 1, the plunger type screw rod mainly comprises two parts, one part is a screw rod, the two parts are distributed in a V shape, materials are melted and pressurized through the screw rod and then conveyed into a cavity of the plunger, and then the injection molding amount is controlled by controlling the moving distance of the piston in the plunger. However, the V-shaped plunger screw has the advantages of large structural volume, large installation space, very high price for purchasing a new machine, and high price for replacing the injection molding unit with the V-shaped structure, the plastic can not be first in and first out because of the diversion of the raw materials from the upper end into the injection pipe, the plastic at the front end of the injection rod stays to cause carbonization, black spots are generated to yellow, and the existing old equipment can not use the injection mechanism with the V-shaped structure, so that repeated investment is caused by purchasing a new opportunity.

Therefore, there is a great need in the art for a product with higher integration and higher ejection pressure.

Disclosure of Invention

The object of the present invention is to provide a precision plunger screw head that overcomes the above-mentioned drawbacks of the prior art.

In order to achieve the purpose of the application, the application provides the following technical scheme.

In a first aspect, the present application provides a precision plunger screw head, the precision plunger screw head is fixedly mounted at the front end of a screw, the screw is coaxially arranged in a delivery channel of a material pipe, and the front end of the material pipe is provided with an injection assembly, and the precision plunger screw head is characterized in that the front end of the plunger screw head is provided with a plunger sealing part, and the injection assembly is provided with a plunger sealing channel worn with the plunger sealing part. According to the application, the injection assembly is fixed at the front end of the material pipe, after the material enters the injection assembly and is gradually filled in the injection assembly, the material is continuously fed, the screw rod is pushed to integrally move backwards, at the moment, the screw rod is pushed forwards by external force, so that the plunger sealing part enters the plunger channel, and because the plunger channel and the plunger sealing part are ground (namely, the tolerance between the plunger channel and the plunger sealing part is very small, when the plunger channel and the plunger sealing part slide relatively, the material cannot leak out from a gap between the plunger channel and the plunger sealing part), at the moment, the injection assembly and the plunger screw head form a cavity and piston structure, and the injection quantity of the material can be controlled by controlling the advancing distance of the plunger screw head, so that the aim of precise injection is fulfilled. In addition, the application does not need to additionally arrange a plunger structure like the prior art, and the whole volume is approximately the same as that of the prior common screw rod.

In one embodiment of the first aspect, a top portion of the plunger sealing portion is coaxially provided with a weight-reducing portion, the weight-reducing portion is cylindrical, and an outer diameter of the weight-reducing portion is smaller than an outer diameter of the plunger sealing portion. It is well known in the field of injection molding screws that 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 application, the weight reduction part is arranged for two purposes, namely, the purpose of reducing the weight of injection molding, achieving the purpose of reducing the weight, reducing the residence time of materials in a material pipe, reducing the occurrence of carbonization, and the purpose of the plunger sealing part is arranged for fine sealing glue, and the purpose of increasing the injection pressure.

In one embodiment of the first aspect, a ratio of an outer diameter of the weight-reduction portion to an outer diameter of the plunger seal portion is 0.1 to 0.9:1.

In one embodiment of the first aspect, a ratio of an outer diameter of the plunger seal to an outer diameter of the screw is 0.1 to 0.9:1. The diameter of the plunger sealing part is preferably 1D-100D, more preferably, the diameter of the plunger sealing part is 1D-22D, and certainly, the diameter of the plunger sealing part is ensured to be smaller than the diameter of the screw rod, so that the weight reduction and pressurization functions are achieved.

In one embodiment of the first aspect, a guiding portion, a sealing portion and a guiding groove portion are sequentially arranged between the connecting screw teeth of the plunger screw head and the plunger sealing portion, a meson is fixed on the outer side of the guiding portion, a non-return ring is sleeved on the outer side of the sealing portion, and the outer diameter of the non-return ring and the inner diameter of the material conveying channel of the material pipe are ground. The meson, the non-return ring and the diversion trench are common structures of the existing screw, which is a plunger screw head form used by the application, and the sealing surface can be formed by the non-return ring and the meson when the non-return ring and the meson are in butt joint, so that the sealing structure is formed.

In an embodiment of the first aspect, the non-return ring comprises any one of a fork non-return ring or a ring non-return ring, wherein the fork non-return ring is more suitable for a scene with higher melt adhesive speed.

In one embodiment of the first aspect, the plunger screw head comprises a plunger unit, a connected non-return ring and a marble, wherein a plunger sealing part is arranged at the front end of the plunger unit, an installation cavity is arranged at the tail end of the plunger unit, a plurality of second material passing channels which are internally and externally communicated are arranged at the front end of the installation cavity, internal threads are arranged on the inner wall of the installation cavity, external threads matched with the internal threads are arranged on the outer wall of the front end of the connected non-return ring and fixedly arranged at the tail end of the plunger unit, a containing cavity is arranged at the axis center of the foremost end of the connected non-return ring, the inner wall of the tail end of the containing cavity is in a round sphere shape, a first material passing channel which is internally and externally communicated is arranged at the inner wall of the tail end of the containing cavity, the opening diameter of the foremost end of the containing cavity is enlarged, the marble is placed in the containing cavity, the diameter of the marble is the same as the diameter of the inner wall of the tail end of the containing cavity, and the connecting screw teeth are fixedly arranged at the front axis center of the screw through the connecting screw teeth. The second plunger screw head is in the form of the application, and the forward and backward movement of the marble is utilized to realize the switching between sealing and feeding.

In one embodiment of the first aspect, the injection assembly includes a plunger cylinder having a plunger seal channel at an axial center thereof, the plunger cylinder being fixedly mounted to a forward end of the tube, and a nozzle fixedly mounted to a forward end of the plunger cylinder.

Compared with the prior art, the invention has the beneficial effects that:

(1) The plunger structure is skillfully integrated into the screw rod, the integration degree is high, the volume of the plunger type screw rod is greatly reduced, and the weight is smaller;

(2) The injection molding device is suitable for injection molding with different metering, and the extrusion amount of materials is controlled by controlling the stroke amount of the plunger screw head, so that the purpose of precise injection molding is achieved;

(3) The injection pressure of the material can be increased, the residence time of the material in the material pipe is reduced, and the carbonization is reduced.

Drawings

FIG. 1 is a schematic view of a prior art ram screw;

FIG. 2 is a schematic view of the overall assembly of a precision screw head set to a screw;

FIG. 3 is a schematic view showing the structure of a head set of a plunger screw according to embodiment 1;

FIG. 4 is an enlarged schematic view of a portion of the plunger screw head during glue in;

FIG. 5 is an enlarged partial schematic view of a screw head set at the beginning of injection molding;

FIG. 6 is an enlarged partial schematic view of the screw head set as the screw continues to advance;

FIG. 7 is an enlarged partial schematic view of the screw head set with the screw restarting the feeding of glue;

FIG. 8 is a schematic structural view of a plunger cylinder;

FIG. 9 is a schematic view showing the overall structure of a head of a plunger screw according to embodiment 2;

FIG. 10 is a schematic view of the structure of the plunger unit of FIG. 3;

FIG. 11 is a schematic structural view of the conjoined check ring of FIG. 3;

FIG. 12 is a schematic view showing the structure of the plunger rod head according to example 2;

Fig. 13 is a schematic diagram of the structure of the plunger screw head and the plunger cylinder when sealing.

In the drawing, 1 is a material pipe, 11 is a material inlet, 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 material passing channel, 432 is an installation cavity, 433 is an internal thread, 44 is a connected non-return ring, 441 is a second material passing channel, 442 is a connecting screw thread, 443 is a containing 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 screw thread, 5 is a nozzle, 6 is a non-return ring, and 7 is a meson.

Detailed Description

Unless defined otherwise, technical or scientific terms used in the specification and claims should be given the ordinary meaning as understood by one of ordinary skill in the art to which the invention pertains. All numerical values recited herein as being from the lowest value to the highest value refer to all numerical values obtained in increments of one unit between the lowest value and the highest value when there is a difference of more than two units between the lowest value and the highest value.

In the following, specific embodiments of the present invention will be described, and it should be noted that in the course of the detailed description of these embodiments, it is not possible in the present specification to describe all features of an actual embodiment in detail for the sake of brevity. Modifications and substitutions of embodiments of the invention may be made by those skilled in the art without departing from the spirit and scope of the invention, and the resulting embodiments are also within the scope of the invention.

Examples

The following will describe embodiments of the present invention in detail, and the embodiments and specific operation procedures are given by implementing the present invention on the premise of its technical solution, but the scope of protection of the present invention is not limited to the following embodiments.

Example 1

The structure of the precision screw head set after being assembled on an injection molding machine is shown in fig. 2. The precise screw head group comprises a plunger screw head 4 and a plunger cylinder 3, wherein the plunger cylinder 3 is fixedly connected with the top end of a material pipe 1 of an injection molding machine, a nozzle 5 is fixed at the front end of the plunger cylinder 3, the plunger screw head 4 is fixedly arranged at the top end of a screw rod 2, and a material inlet 11 is arranged on the material pipe 1.

As shown in fig. 3, in the present embodiment, the plunger rod head group refers to a name obtained by assembling the plunger rod head 4, the check ring 6, and the meson 7 together. Wherein, plunger screw head 4 is integrated into one piece structure, from beginning to end includes weight-reducing portion 41, plunger sealing portion 42, guiding gutter portion 46, sealing portion 47, guiding portion 48 and connection screw tooth 49 in proper order, and wherein, connection screw tooth 49 is fixed in the front end center department of screw rod 2 to make plunger screw head 4 and screw rod 2 fixed through the screw thread. The diameter of the plunger seal 42 is smaller than the diameter of the screw 2, and the effect of weight reduction and pressurization is achieved. Meanwhile, the diameter of the weight-reducing portion 41 is smaller than that of the plunger seal portion 42, and the weight-reducing and pressurizing effects are further achieved. The meson 7 is fixed to the outside of the guide portion 48, and the two are fixed by screw connection. The periphery of the channel portion 46 is provided with 4 channels of used glue. The check ring 6 is sleeved outside the sealing portion 47, and the axial length of the sealing portion 47 is greater than the axial length of the check ring 6, namely, the relative position of the check ring 6 and the plunger screw head 4 is that the front end face of the check ring 6 is stopped at the forefront and the tail end face of the diversion trench 46 is abutted, and the tail end face of the check ring 6 is stopped at the rearmost and the front end face of the meson 7 is abutted. The non-return ring can be a ring non-return ring or a fork non-return ring, which are all the prior art. The outer diameter of the non-return ring 6 and the inner wall of the material pipe 1 are ground, as shown in fig. 4-7.

The plunger cylinder 3 is constructed as shown in fig. 8, and has a structure similar to that of a flange in a common screw 2, and is fixed to the front end of the pipe 1 by a plurality of bolts. The axial center of the plunger cylinder 3 is provided with a through channel, and a mounting channel 33, a plunger sealing channel 32 and a connecting channel 31 are arranged from the front end to the tail end in sequence. Wherein the inner diameter of the connecting channel 31 is the same as the inner diameter of the material pipe 1, and the connecting channels are mutually communicated without gaps. The inner diameter of the plunger seal channel 32 and the outer diameter of the plunger seal 42 are precisely milled (i.e., less than 0.01mm tolerance between the two, but relative sliding between the two is possible). The axial length of the plunger seal channel 32 is greater than the axial length of the plunger seal 42. The inner wall of the mounting channel 33 is provided with threads, and the nozzle 5 is fixedly arranged in the mounting channel 33. After the plunger seal 42 begins to be inserted into the plunger seal channel 32, at this time, the material is cut off by the plunger seal 42, and the sealing effect is achieved. At this time, the volume of the material injected from the nozzle 5 can be controlled by controlling the advancing distance of the plunger seal 42, thereby achieving the effect of precision injection molding.

The whole working process is as follows:

At the time of injecting the glue, the melted material flows forward with the rotation of the screw 2, and at this time, the check ring 6 is positioned at the forefront position, that is, the front end of the check ring 6 abuts against the rear end of the flow guiding groove 46, and the plunger seal 42 is not inserted into the plunger seal channel 32, as shown in fig. 4. The material flow path is that the gap between the screw rod 2 and the inner wall of the material pipe 1, the gap between the meson 7 and the inner wall of the material pipe 1, the gap between the inner wall of the non-return ring 6 and the outer wall of the sealing part 47, the flow guiding groove, the channel of the plunger cylinder 3 and the channel of the nozzle 5, the cold glue nozzle in the mold prevents the material from flowing out of the front end of the nozzle 5 due to the contact of the mold and the nozzle 5, the material is gradually stored in the channel of the nozzle 5, and when the stored material is continuously fed after the stored material is filled in the channel of the nozzle 5 and the channel of the plunger cylinder 3, the volume of the material is gradually increased in the metering chamber, a reverse thrust is generated, and the screw rod and the plunger screw head 4 are gradually reversed.

When injection molding is started, the outlet at the forefront end of the nozzle 5 is opened, and then the screw rod 2 is pushed forward by the driving device, and at this time, the screw rod 2, the whole plunger screw head 4 and the meson 7 move forward. Since the check ring 6 is merely sleeved outside the sealing portion 47, that is, is not fixed, the check ring 6 does not move forward at this time until the front end of the meson 7 on the plunger rod head 4 abuts against the rear end of the check ring 6, as shown in fig. 5. Therefore, the flow channel of the molten material is cut off by the non-return ring 6 and the meson 7, namely, new material cannot flow forwards, and the material originally stored in the nozzle 5 and the plunger cylinder 3 cannot flow backwards, so that the sealing effect is achieved.

The drive means drives the screw further forward, at which point the screw 2, plunger screw head 4, check ring 6, and meson 7 move together forward until the plunger seal 42 enters the plunger seal channel 32, as shown in fig. 6. Because of the small tolerances between the plunger seal 42 and the plunger seal 32, a structure similar to a barrel and piston is formed, and as the screw 2 continues to advance, the plunger seal 42 pushes the material forward, thereby ejecting material from the nozzle. Since the diameter of the plunger seal channel 32 is determined, the injection volume of the material can be precisely controlled by controlling the advancing length of the plunger seal 42 (i.e., the stroke of the screw).

When the injection molding is completed, the melt adhesive driving device starts to rotate, the material is pushed to the metering chamber from the discharging opening through the thrust generated by the spiral angle of rise, and when the material is pushed to the tail end of the non-return ring 6, the material pushes the non-return ring 6 to move forward until the front end of the non-return ring 6 abuts against the tail end of the diversion trench part 46, so that the flow channel of the molten material is re-opened, as shown in fig. 7. As the volume of the material in the metering chamber does not increase, the material cannot flow out of the front hole of the nozzle 5, and a reverse thrust force is generated by the material to push the plunger screw set to move backwards until the plunger sealing part 42 is completely pulled out of the plunger sealing channel 32, so that the state shown in fig. 4 is restored, and the next injection molding can be continued.

Example 2

A tube, screw, plunger cylinder and nozzle similar to example 1 was used, except that a different form of plunger screw head was used, as follows.

In this embodiment, as shown in fig. 9 to 13, the structure of the plunger screw head 4 mainly includes two detachable parts, the front section is a plunger unit, and includes a weight-reducing part 41, a plunger sealing part 42, and a connecting part 43 in order, which are an integrated structure. The rear end axle center department of connecting portion 43 sets up installation cavity 432, and the rear end inner wall of installation cavity 432 is equipped with internal thread 433, and the front end of installation cavity 432 is equipped with inside and outside first material passageway 431 that link up. The rear section of the plunger screw head 4 is provided with a conjoined check ring 44, a containing cavity 443 is arranged at the axial center of the front end of the conjoined check ring 44, the inner wall of the tail end of the containing cavity 443 is in a sphere shape, the inner wall of the tail end is provided with a second material passing channel 441 which is internally and externally communicated, and the diameter of the opening of the front end of the containing cavity 443 is increased. The outer wall of the forefront end of the conjoined check ring 44 is provided with an external thread 444, and the external thread 444 is meshed with an internal thread 433 at the axle center of the connecting part 43, so that the plunger screw head 4 is fixed back and forth into a whole. The outer diameter of the joint part of the conjoined check ring 44 and the connecting part 43 is in grinding fit with the inner diameter of the material pipe 1. A connecting screw 442 is provided on the outer wall of the tail end of the conjoined check ring 44, and the entire plunger screw head 4 is fixed to the front end of the screw 2 by the connecting screw 442. A marble 45 is provided in the receiving cavity 443, and the diameter of the marble 45 is the same as the diameter of the inner wall of the rear end of the receiving cavity 443. The marble 45 can roll back and forth in the accommodating cavity 443, and when the marble 45 is abutted against the side wall of the tail end of the accommodating cavity 443, the marble 45 can block all the second material passing channels 441 to play a role of sealing glue, and when the marble 45 is separated from the tail end of the accommodating cavity 443, materials can sequentially pass through the second material passing channels 441, the accommodating cavity 443, the mounting cavity 432 and the first material passing channels 431 and finally reach the inside of the plunger cylinder 3.

The specific process is as follows:

When glue is fed, the material enters the material pipe 1 from the feeding port 11, the material is melted into colloid under the conveying of the screw rod 2, the material moves forward from the rear end of the material pipe 1, when the material reaches the conjoined check ring 44 of the plunger screw head 4, the material can only enter from the second passing channel 441 because the conjoined check ring 44 is in a grinding state with the inner wall of the material pipe 1, then sequentially passes through the accommodating cavity 443, the mounting cavity 432, the first passing channel 431 and the plunger cylinder 3, finally reaches the nozzle 5, the material is controlled to be not discharged, the material is gradually stored in the channel of the nozzle 5, and when the material is continuously fed after the stored material fills the channels of the nozzle 5 and the plunger cylinder 3, the screw rod 2 and the plunger screw head 4 can gradually backward.

When injection molding is started, the outlet at the forefront end of the nozzle 5 is opened, and then the screw rod 2 is pushed to move forwards, and the whole plunger screw rod head 4 moves forwards together with the outlet. Because of the inertia, the advancing speed of the receiving cavity 443 must be greater than that of the marble 45, so that the marble 45 gradually moves backward relative to the receiving cavity 443 until the marble abuts against the inner wall of the tail end of the receiving cavity 443, and thus, the marble 45 blocks all the second passing channels 441 to form a sealing state, as shown in fig. 12, that is, new material cannot flow forward, and material originally stored in the nozzle 5 and the plunger cylinder 3 cannot flow backward.

The forward movement of the push screw 2 continues until the plunger seal 42 begins to enter the plunger seal channel 32, as shown in fig. 13. Because of the small tolerances between the plunger seal 42 and the plunger seal 32, a structure similar to a barrel and piston is formed, and as the screw 2 continues to advance, the plunger seal 42 pushes the material forward, thereby ejecting material from the nozzle. Since the diameter of the plunger seal channel 32 is determined, the injection volume of the material can be precisely controlled by controlling the advancing length of the plunger seal 42 (i.e., the stroke of the screw 2).

When the injection molding is completed, the control screw 2 is moved backward as a whole, the marble 45 is firstly separated from the rear end of the receiving cavity 443, the second passing channel 441 is opened again, new material can be injected forward, and then the plunger seal 42 is also separated from the plunger seal channel 32, and the material can enter the plunger cylinder 3 and the nozzle 5.

The embodiments are described above in order to facilitate the understanding and application of the present application by those of ordinary skill in the art. It will be apparent to those skilled in the art that various modifications can be made to these embodiments and that the general principles described herein may be applied to other embodiments without the use of inventive faculty. Accordingly, the present application is not limited to the embodiments herein, and those skilled in the art, based on the present disclosure, make improvements and modifications within the scope and spirit of the application.

Claims (8)

1. The precise plunger screw head is fixedly arranged at the front end of a screw rod, the screw rod is coaxially arranged in a conveying channel of a material pipe, and an injection assembly is arranged at the front end of the material pipe.

2. The precision plunger screw head of claim 1, wherein the top of the plunger seal is coaxially provided with a weight-reducing 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 seal.

3. The precision plunger screw head of claim 2, wherein the ratio of the outer diameter of the weight reduction portion to the outer diameter of the plunger seal portion is 0.1-0.9:1.

4. The precision plunger screw head of claim 1, wherein the ratio of the outer diameter of the plunger seal to the outer diameter of the screw is 0.1-0.9:1.

5. The precise plunger screw head according to claim 1, wherein a guide part, a sealing part and a diversion trench part are sequentially arranged between the connecting screw teeth and the plunger sealing part of the plunger screw head, a meson is fixed on the outer side of the guide part, a non-return ring is sleeved on the outer side of the sealing part, and the outer diameter of the non-return ring and the inner diameter of the material conveying channel of the material pipe are ground.

6. The precision plunger screw head of claim 5, wherein the check ring comprises any one of a fork check ring or a ring check ring.

7. The precise plunger screw head of claim 1, wherein the plunger screw head comprises a plunger unit, a connected non-return ring and a marble, wherein a plunger sealing part is arranged at the front end of the plunger unit, an installation cavity is arranged at the tail end of the plunger unit, a plurality of second passing channels which are internally and externally communicated are arranged at the front end of the installation cavity, internal threads are arranged on the inner wall of the installation cavity, external threads matched with the internal threads are arranged on the outer wall of the front end of the connected non-return ring and are fixedly arranged at the tail end of the plunger unit, an accommodating cavity is arranged at the axis center of the foremost end of the connected non-return ring, the tail end inner wall of the accommodating cavity is in a sphere shape, the inner wall of the tail end is provided with a first passing channel which is internally and externally communicated, the inner diameter of the middle part of the accommodating cavity is constant, the opening diameter of the foremost end of the accommodating cavity is enlarged, the marble is placed in the accommodating cavity, the diameter of the marble is the same as the diameter of the tail end inner wall of the accommodating cavity, connecting threads are arranged at the tail end of the connecting threads and are fixedly arranged at the front axis of the screw through connecting threads.

8. The precision plunger screw head of claim 1, wherein the injection assembly comprises a plunger cylinder and a nozzle, wherein a plunger sealing channel is arranged at the axis of the plunger cylinder, the plunger cylinder is fixedly arranged at the front end of the material pipe, and the nozzle is fixedly arranged at the front end of the plunger cylinder.