CN112388923A

CN112388923A - Can realize injection molding machine that dynamic injection moulding used

Info

Publication number: CN112388923A
Application number: CN202011161206.4A
Authority: CN
Inventors: 陈明华
Original assignee: Suzhou Gienkee Plastics Technology Co ltd
Current assignee: Suzhou Gienkee Plastics Technology Co ltd
Priority date: 2020-10-27
Filing date: 2020-10-27
Publication date: 2021-02-23

Abstract

The invention discloses an injection molding machine capable of realizing dynamic injection molding, which comprises a shell, a charging barrel, a screw and a power system, wherein the power system comprises a power unit and a driving unit, and the power unit comprises a screw rod with forward and reverse threaded sections; the driving unit comprises a first driver and a second driver which respectively drive the first nut and the second nut to rotate in the same direction or in the opposite direction. On one hand, the invention realizes the actions of injection, pressure maintaining, feeding and loosening of the screw rod by controlling the steering and the speed of the first nut and the second nut, and can implement a dynamic injection molding technology particularly in the actions of pressure maintaining and feeding, thereby improving the product yield and the feeding efficiency; on the other hand, the inertia is small, the action response is fast, the size is small, the two drivers do work simultaneously, the specification of the drivers is reduced, and the price is low.

Description

Can realize injection molding machine that dynamic injection moulding used

Technical Field

The invention belongs to the field of injection molding machines, and particularly relates to an injection molding machine capable of realizing dynamic injection molding.

Background

Injection molding machines, also known as injection molding machines or injection molding machines. It is a main forming equipment for making various shaped plastic products from thermoplastic plastics or thermosetting plastics by using plastic forming mould. The injection molding machine can heat the plastic, apply high pressure to the molten plastic, and inject it to fill the mold cavity.

Specifically, the injection motion state mainly includes the following actions:

1) and injection: the injection motor drives the rotary screw rod to push the injection screw rod to advance;

2) and pressure maintaining: keeping the pressure intensity of the die cavity and the material pipe unchanged for a period of time, and continuously applying work by the injection motor;

3) and feeding materials: the feeding motor drives the glue injection screw to rotate (the glue injection screw can only rotate in one direction);

4) and loosening after loosening: the pressure of screw rod anterior segment can be bigger and bigger to produce the backpressure when the reinforced motor drives and penetrates gluey screw rod rotation, needs ball to move backward at this moment and releases the backpressure, reinforced motor and the simultaneous working of ejection motor this moment.

Meanwhile, the dynamic injection molding technology comprises the following steps: the injection screw generates axial pulsating oscillation force in the process of injection molding processing, namely, the injection screw generates axial vibration in the pressure maintaining and feeding stage, so that the product yield and the feeding efficiency are improved.

At present, the injection molding machine mainly has two design schemes:

the first scheme is as follows: jet out and respectively adopt a servo motor to pass through synchronous pulley transmission with reinforced, this scheme is adopted in the product design of present most manufacturers, and the advantage of this scheme is: realize great torque output through band pulley speed reduction, the price is relatively cheap, and the shortcoming is: a) the inertia is large, the response is slow, and the transmission efficiency is high without direct drive; b) the belt is flexible and subject to wear.

Scheme II: jet out and reinforced respectively adopting a servo motor directly to drive, require very high to the motor, few manufacturers adopt this design, and mainly also use on small-size machine, the advantage of this scheme is: the inertia is low, the response speed is high, and the transmission efficiency is high; the disadvantages are that: a) the motor torque required by the injection device with the same specification is high, and the price is high; b) it is not suitable for large injection seat.

In the two schemes, because the injection and feeding actions are independently moved, a thrust bearing is switched at the feeding position, and the two motors are independently used.

Therefore, most manufacturers adopt a belt transmission scheme, and dynamic injection molding is difficult to realize due to large inertia and belt flexibility; the direct drive of servo motors used by a small number of manufacturers can realize dynamic injection, but the actual application is not seen yet, the price is too high compared with an injection machine with the same specification, and the direct drive of servo motors is only applied to a small-sized machine at present due to the limitation of the motors.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide an improved injection molding machine capable of realizing dynamic injection molding.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

an injection molding machine capable of realizing dynamic injection molding, comprising:

a housing;

the charging barrel comprises a barrel body and a nozzle, wherein the barrel body is internally provided with a cavity and is communicated with the shell from one end part, and the nozzle is positioned at the other end part of the barrel body;

a screw extending along the length of the barrel;

the power system is used for driving the screw to rotate around the axis of the screw and to linearly move along the length direction of the screw, and particularly comprises a power unit and a driving unit, wherein the axis of the power unit coincides with the axis of the screw and moves synchronously relative to the screw, the power unit comprises a screw rod with forward and reverse threaded sections, a first nut and a second nut which are respectively matched with the forward and reverse threaded sections, one end of the screw rod is connected with the end of the screw rod, which is far away from the nozzle, the other end of the screw rod can penetrate out of the end, which is far away from the charging barrel, of the machine shell, and the driving unit comprises a first driver and a second driver which respectively drive the first nut and the second nut to.

Preferably, the axes of the forward and reverse screw flights are collinear and coincide with the screw axis.

According to a specific embodiment and preferred aspect of the present invention, the forward and reverse thread segments have equal thread pitches. This facilitates the motion control of the various states during the injection molding process.

Preferably, under the condition that the first nut and the second nut are at the same speed and opposite in rotation direction, the screw rod is driven by the screw rod to advance or retreat. This makes it possible to perform an injection operation or a back-loosening (casting prevention, i.e., prevention of the sol from flowing back into the mold) operation.

Further, under the repeated switching of the first nut and the second nut which are at the same speed and synchronously rotate reversely, the screw rod drives the screw rod to repeatedly advance and retreat. In this way, the motor output torque force of the injection operation is maintained, and at the same time, the first nut and the second nut are synchronously reversed, the same frequency and amplitude are maintained, and the screw rod drives the screw rod to repeatedly advance and retreat.

Preferably, under the condition that the first nut and the second nut rotate in the same direction and a speed difference is formed between the first nut and the second nut, wherein the speed difference is repeatedly switched between positive and negative, and the screw rod drives the screw rod to repeatedly advance and retreat. That is, the first nut and the second nut are simultaneously reversed to realize the in-situ rotation of the screw rod, and on the basis of the action, the first nut and the second nut are superposed to have a speed difference, for example, the rotating speed of the first nut is V + V amplitude, the rotating speed of the second nut is V-V amplitude, at the moment, the screw rod advances, and the difference between the rotating speed of the first nut and the rotating speed of the second nut is 2V amplitude (positive value); the rotating speed of the first nut is V-V amplitude, the rotating speed of the second nut is V + V amplitude, the screw rod retreats at the moment, and meanwhile, the difference value between the rotating speed of the first nut and the rotating speed of the second nut is-2V amplitude (negative value).

Further, under the condition that the speed difference value is in the positive and negative repeated switching, the ejection end part of the screw rod generates back pressure backwards, the first nut reversing speed is smaller than the second nut reversing speed, the screw rod drives the screw rod to retreat, and the speed and the retreating distance are controlled through the pressure sensor. Therefore, the motion of the two speed difference control screw rods is repeated, so that the dynamic injection molding technology can be implemented, and the feeding action is convenient to complete.

The first driver and the second driver are the same and are arranged in the shell side by side, the first driver comprises a first stator and a first rotor, and the first rotor is fixedly connected with a first nut; the second driver comprises a second stator and a second rotor, and the second rotor is fixedly connected with the second nut.

Preferably, the first rotor and the second rotor are rotatably provided on the housing through rotary bearings from both end portions, respectively.

The lead screw, the first nut, and the second nut constitute two sets of ball screw structures that share one lead screw.

Meanwhile, the screw rod is connected with the screw rod through an external piece.

Due to the implementation of the technical scheme, compared with the prior art, the invention has the following advantages:

on one hand, the injection molding, pressure maintaining, feeding and loosening actions of the screw rod are realized by controlling the steering and the speed of the first nut and the second nut, and particularly, a dynamic injection molding technology can be implemented in the pressure maintaining and feeding actions so as to improve the product yield and the feeding efficiency; on the other hand, the inertia is small, the action response is fast, the size is small, the two drivers do work simultaneously, the specification of the drivers is reduced, and the price is low.

Drawings

FIG. 1 is a schematic sectional view of the structure of an injection molding machine according to the present invention;

FIG. 2 is a state of motion (one) of the ball screw of FIG. 1;

FIG. 3 is a view showing a moving state (II) of the ball screw shown in FIG. 1;

FIG. 4 shows the state of motion of the ball screw of FIG. 1 (III);

fig. 5 is a movement state (four) of the ball screw of fig. 1;

wherein: 1. a housing;

2. a charging barrel; 20. a barrel; 21. a nozzle;

3. a screw;

4. a power system; 40. a power unit; 400. a screw rod; 401. a first nut; 402. a second nut; 403. an external connector; 41. a drive unit; 411. a first driver; a1, a first stator; b1, a first rotor; 412. a second driver; a2, a second stator; b2, a second rotor; c. and rotating the bearing.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of embodiments in many different forms than those described herein and that modifications may be made by one skilled in the art without departing from the spirit and scope of the application and it is therefore not intended to be limited to the specific embodiments disclosed below.

In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the present application.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

As shown in fig. 1, the injection molding machine capable of realizing dynamic injection molding according to the present embodiment includes a housing 1, a barrel 2, a screw 3, and a power system 4.

Specifically, the charging barrel 2 includes a barrel 20 having a cavity therein and communicating with the casing 1 from one end, and a nozzle 21 located at the other end of the barrel 20, wherein the barrel 20 is provided with a plastic material inlet.

The screw 3 extends along the length of the barrel 2.

The power system 4 is used for driving the screw rod 3 to rotate around the axis of the screw rod and move linearly along the length direction of the screw rod.

In this example, the power system 4 includes a power unit 40 whose axis coincides with the axis of the screw 3 and which moves synchronously relative to the screw 3, and a drive unit 41.

The power unit 40 comprises a screw rod 400 with forward and reverse threaded sections, and a first nut 401 and a second nut 402 which are respectively matched with the forward and reverse threaded sections, wherein one end part of the screw rod 400 is connected with the end part of the screw rod 3 far away from the nozzle 21, and the other end part of the screw rod can penetrate out of the end part of the machine shell 1 far away from the charging barrel 2.

Specifically, the axial leads of the forward and reverse thread sections are collinear and coincide with the axial lead of the screw rod 3.

In this example, the forward and reverse thread segments have equal thread pitches. This facilitates the motion control of the various states during the injection molding process.

The driving unit 41 includes a first driver 411 and a second driver 412 that drive the first nut 401 and the second nut 402 to rotate in the same direction or in opposite directions, respectively.

The first driver 411 and the second driver 412 are identical and are arranged in the casing 1 side by side, the first driver 411 comprises a first stator a1 and a first rotor b1, and the first rotor b1 is fixedly connected with the first nut 401; the second driver 412 includes a second stator a2 and a second rotor b2, the second rotor b2 is fixedly connected to the second nut 402.

The first rotor a1 and the second rotor a2 are rotatably provided on the housing 1 from both ends via rotary bearings c, respectively.

The screw 400, the first nut 401, and the second nut 402 constitute two sets of ball screw structures that share one screw.

Meanwhile, the screw rod 400 is connected with the screw rod 3 through an external connector 403. Conventionally, the extension is a spline and a half-moon ring connection.

In this example, taking the screw 400 as an example that one end near the injection is a right-handed thread and the other end is a left-handed thread, the operation state of the screw 400 is explained as follows:

1) and an injection operation: the first rotor and the first nut rotate reversely, the second rotor and the second nut rotate forwardly at the same rotating speed, and the forward movement of the screw rod can be realized, so that the ejection of the dissolved material is implemented;

2) and pressure maintaining action: keeping the motor output torque force of the injection action, simultaneously keeping the synchronous reverse rotation of the first nut and the second nut, repeatedly switching the steering directions of the first nut and the second nut (combining with the figures 2 and 3), keeping the same frequency and amplitude, and enabling the screw rod to drive the screw rod to repeatedly advance and retreat, wherein at the moment, the dynamic injection molding technology can be implemented;

3) and feeding: (a) the first nut and the second nut are simultaneously reversed to realize the in-situ rotation of the screw rod, on the basis of action, a speed difference of the first nut and the second nut is superposed, as shown in a combined graph 4, the rotating speed of the first nut is V + V amplitude, the rotating speed of the second nut is V-V amplitude, at the moment, the screw rod moves forward, and meanwhile, the difference value between the rotating speed of the first nut and the rotating speed of the second nut is 2V amplitude (positive value); referring to fig. 5, the rotation speed of the first nut is V-V amplitude, the rotation speed of the second nut is V + V amplitude, the screw rod retreats, the difference between the rotation speed of the first nut and the rotation speed of the second nut is-2V amplitude (negative value), and when the difference is repeatedly switched between positive and negative, the same frequency and amplitude are maintained, so that the screw rod drives the screw rod to repeatedly advance and retreat, and at this time, a dynamic injection molding technique can be implemented; (b) under the action recorded in the step (a), the screw rod continuously moves, the ejection end part of the screw rod generates back pressure backwards, the reverse rotation speed of the first nut is lower than that of the second nut, the screw rod drives the screw rod to retreat, the speed and the retreat distance are controlled by a pressure sensor, and the step (a) and the step (b) are repeated until the feeding is finished;

4) after loosening action (tape casting): the first nut rotates positively, the second nut rotates negatively, the two nuts rotate identically, and the screw rod drives the screw rod to retreat at the moment, so that molten material is prevented from flowing back to the die.

In summary, the present embodiment has the following advantages:

1) the injection, pressure maintaining, feeding and loosening actions of the screw rod are realized by controlling the steering and the speed of the first nut and the second nut, and particularly, a dynamic injection molding technology can be implemented in the pressure maintaining and feeding actions so as to improve the product yield and the feeding efficiency;

2) compared with synchronous belt transmission adopted by most manufacturers, the belt is in rigid connection, so that the inertia is low and the response speed is high; compared with the existing servo motor direct drive technology, the motor utilization efficiency of the scheme is high (two motors can do work simultaneously), the rated power of the motor used by the injection molding machine with the same specification can be smaller, and the manufacturing cost of the injection molding machine can be reduced;

3) the switching of lead screw and screw rod does not need thrust bearing switching, direct spline and half moon ring connect can, simultaneously, compact structure, it is small.

The present invention has been described in detail in order to enable those skilled in the art to understand the invention and to practice it, and it is not intended to limit the scope of the invention, and all equivalent changes and modifications made according to the spirit of the present invention should be covered by the present invention.

Claims

1. An injection molding machine capable of realizing dynamic injection molding, comprising:

a housing;

the charging barrel comprises a barrel body and a nozzle, wherein the barrel body is internally provided with a cavity and is communicated with the shell from one end part, the nozzle is positioned at the other end part of the barrel body, and a plastic raw material inlet is formed in the barrel body;

a screw extending along a length of the barrel;

the power system is used for driving the screw rod to rotate around the axis of the screw rod and move linearly along the length direction of the screw rod,

the method is characterized in that:

the driving system comprises a shaft axis and a screw shaft axis which coincides with the screw and a driving unit, wherein the power unit comprises a screw rod with a forward and reverse thread section, a first nut and a second nut which are matched with the forward and reverse thread section respectively, one end part of the screw rod is far away from the screw rod, the end part of the screw rod is connected with the end part of the nozzle, the other end part of the screw rod can be far away from the casing, the end part of the charging barrel penetrates out of the casing, and the driving unit comprises a first driver and a second driver which drive the first nut and the second nut in the same direction or in the reverse direction.

2. An injection molding machine capable of achieving dynamic injection molding according to claim 1, characterized in that: the axial leads of the forward and reverse threaded sections are collinear and coincide with the axial lead of the screw.

3. An injection molding machine capable of realizing dynamic injection molding according to claim 1 or 2, characterized in that: the thread pitches of the forward and reverse thread sections are equal.

4. An injection molding machine capable of achieving dynamic injection molding according to claim 3, characterized in that: and under the condition that the first nut and the second nut are at the same speed and opposite in rotation direction, the screw rod is driven by the screw rod to move forwards or backwards.

5. An injection molding machine capable of achieving dynamic injection molding according to claim 4, characterized in that: and under the repeated switching of the first nut and the second nut which are at the same speed and synchronously rotate reversely, the screw rod is driven by the screw rod to repeatedly advance and retreat.

6. An injection molding machine capable of realizing dynamic injection molding according to claim 4 or 5, characterized in that: and under the condition that the first nut and the second nut rotate in the same direction and a speed difference is formed between the first nut and the second nut, wherein the speed difference is repeatedly switched between positive and negative, and the screw rod drives the screw rod to repeatedly advance and retreat.

7. An injection molding machine capable of achieving dynamic injection molding according to claim 6, characterized in that: under the repeated switching of the speed difference between the positive and negative, the ejection end part of the screw generates back pressure backwards, the first nut reverse rotation speed is smaller than the second nut reverse rotation speed, and the screw rod drives the screw to retreat.

8. An injection molding machine capable of achieving dynamic injection molding according to claim 1, characterized in that: the first driver and the second driver are the same and are arranged in the shell side by side, the first driver comprises a first stator and a first rotor, and the first rotor is fixedly connected with the first nut; the second driver comprises a second stator and a second rotor, and the second rotor is fixedly connected with the second nut.

9. An injection molding machine capable of performing dynamic injection molding according to claim 8, wherein: the first rotor and the second rotor are respectively and freely rotatably arranged on the shell from two end parts through rotating bearings.

10. An injection molding machine capable of achieving dynamic injection molding according to claim 1, characterized in that: the screw rod, the first nut and the second nut form two groups of ball screw structures sharing one screw rod, wherein the screw rod is connected with the screw rod through an external piece.