CN112297357A

CN112297357A - Injection mold

Info

Publication number: CN112297357A
Application number: CN202011079978.3A
Authority: CN
Inventors: 陈盈; 欧良明
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-10-10
Filing date: 2020-10-10
Publication date: 2021-02-02

Abstract

The invention belongs to the technical field of molds, and particularly relates to an injection mold which comprises a movable mold and a fixed mold; an upper cavity is formed in the movable die; a positioning rod is arranged on the movable die; the fixed die is provided with a lower cavity; the fixed die is provided with a positioning hole; the positioning rod is inserted into the positioning hole; a guide groove is formed in the positioning rod; a positioning bulge is arranged on the inner wall of the positioning hole and can be inserted into the guide groove; an air bag is arranged on the bottom surface of the positioning hole; the bottom surface of the positioning rod can contact the air bag and extrude the air bag; an injection molding hole is formed in the bottom surface of the lower cavity in the fixed die; a bushing is arranged in the injection molding hole; a first spring is mounted on the bushing; a movable cavity III is formed in the fixed die; a buffer rod and a spring II are arranged in the movable cavity III; an air release hole is formed in the fixed die; the invention has accurate positioning, is not easy to loosen after the die is closed, and is convenient for exhausting the air in the die.

Description

Injection mold

Technical Field

The invention belongs to the technical field of molds, and particularly relates to an injection mold.

Background

The mould is various moulds and tools for obtaining required products by injection molding, blow molding, extrusion, die casting or forging forming, smelting, stamping and other methods in industrial production. A mold is a tool used to make a shaped article, the tool being made up of various parts, different molds being made up of different parts. The processing of the appearance of an article is realized mainly through the change of the physical state of a formed material. When the existing mould is installed and used for the first time, small dislocation may exist between a movable mould and a fixed mould in the mould, the movable mould and the fixed mould are easy to collide when the movable mould and the fixed mould are combined, so that a parting surface of the mould is damaged, the normal use of the mould is influenced, meanwhile, in the using process of the mould, the balance between air exhaust in the mould and the sealing property of the mould is difficult to control, when the sealing property of the mould is improved, the air exhaust in the mould is easy to be inconvenient, the quality of a product is influenced, when the air exhaust difficulty in the mould is reduced, the sealing property of the mould is easy to be poor, when in injection moulding, plastic liquid overflows into a gap between the moulds, so that the product is flapped, and meanwhile, in the using process, the mutual locking between the moulds depends on an additional mould locking force, the mutual locking between the moulds is not mutually locked, the insufficient mould locking force is easy to appear, so that the, gaps occur, so that the product has flash, and the quality of the product is influenced.

The technical scheme is that the device comprises a fixed die and a movable die, wherein die cores are arranged on the surfaces of the fixed die and the movable die, a limiting rod is fixed on the side surface of the fixed die, a limiting groove is formed in the side surface of the movable die, a positioning groove is formed in the surface of the limiting rod, a positioning convex strip matched with the positioning groove is arranged on the inner surface of the limiting groove, the limiting rod is inserted into the limiting groove, and exhaust holes are formed in the surfaces of the fixed die and the movable die; through the positioning groove formed in the surface of the limiting rod and the positioning convex strip arranged on the inner surface of the limiting groove, when the limiting rod is inserted into the limiting groove, the positioning convex strip slides in the positioning groove, so that the limiting rod is positioned through the positioning groove and the positioning convex strip when being arranged in the limiting groove, and the fixed die and the movable die are prevented from being collided due to dislocation of the die cores arranged on the surfaces of the fixed die and the movable die when being reversely attached; but the cover half and the movable mould in this scheme mould can not be locked each other, and the clamping force is not enough probably to appear in the in-process of moulding plastics, leads to the product to appear the overlap, simultaneously, in the use, the mould passes through the air in the exhaust hole discharge mould in this scheme, can not avoid the plastic fluid in the mould to enter into the exhaust hole or flow out through the exhaust hole completely, causes the exhaust hole to block up easily and influences the operation that the pressure boost promoted product quality in the mould in the injection moulding process.

Disclosure of Invention

The invention provides an injection mold, which aims to make up the defects of the prior art, ensure accurate positioning of the mold during mold closing, avoid dislocation, reduce the difficulty of air discharge in the mold, ensure the sealing property of the mold, simultaneously ensure that the molds can be locked with each other, improve the stability of the mold in the injection molding process and avoid the problem of insufficient mold locking force during the injection molding of the mold.

The technical scheme adopted by the invention for solving the technical problems is as follows: the invention relates to an injection mold, which comprises a movable mold and a fixed mold, wherein the fixed mold is fixedly arranged on an injection molding machine; the movable mould is arranged on a movable part on the injection molding machine; the movable mold and the fixed mold can be mutually attached to complete the production of the injection molding piece; an upper cavity is formed in the movable die; the upper cavity is positioned on the side surface of the movable mould close to the fixed mould; a positioning rod is arranged on the movable die; the fixed die is provided with a lower cavity; the lower cavity is positioned on the side surface of the fixed die close to the movable die; the upper die cavity and the lower die cavity correspond to each other, and the edges of the upper die cavity and the lower die cavity are just attached; the fixed die is provided with a positioning hole; the positioning rod is inserted into the positioning hole; when the movable die moves, the positioning rod is not completely separated from the positioning hole; the side surface of the positioning rod is provided with guide grooves distributed along the length direction of the positioning rod; a positioning bulge is arranged on the inner wall of the positioning hole; the positioning protrusion can be inserted into the guide groove, and the positioning protrusion can freely move in the guide groove; an air bag is arranged on the bottom surface of the positioning hole; the bottom surface of the positioning rod can contact the air bag and extrude the air bag; an injection molding hole is formed in the fixed die; the outlet of the injection molding hole is positioned on the bottom surface of the lower cavity on the fixed die; the central line of the injection molding hole is vertical to the bottom surface of the lower cavity; a bushing is arranged in the injection molding hole; one end of the bushing, which is far away from the fixed die, is positioned outside the fixed die, and one end of the bushing, which is far away from the fixed die, is provided with a connector; a first spring is mounted on the bushing; the spring is positioned between the connector on the bushing and the fixed die; the bushing can freely move in the injection molding hole; a movable cavity III is formed in the fixed die; the three movable cavities are two in number and are symmetrically distributed around the central line of the injection molding hole; a buffer rod is arranged in the third movable cavity; the tail end of the buffer rod extends out of the third movable cavity and enters the injection molding hole; the tail end of the buffer rod is arc-shaped and is in contact with one end of the lining in the fixed die; the buffer rod does not exceed the center line of the bushing; a second spring is arranged in the third movable cavity; the second spring is positioned between the bottom surfaces of the three movable cavities and the buffer rod; an air release hole is formed in the fixed die; the air leakage hole is used for communicating the lower cavity with the outside;

when the injection molding machine works, the fixed die and the movable die are correctly installed on the injection molding machine, when the production is started, the movable die is controlled to slowly move towards the fixed die until the fixed die and the movable die are contacted with each other, the die assembly is completed, the upper die cavity and the lower die cavity are connected with each other to form the shape of a product, meanwhile, after the die assembly of the fixed die and the movable die is completed, the injection head of the injection molding machine is controlled to be contacted and pressed on the lining to complete the communication between the injection molding machine and the injection hole, then, the injection molding process of the injection molding machine is controlled to start the injection molding, the production of the injection molding product is completed, meanwhile, in the die assembly process of the fixed die and the movable die, the positioning rod on the movable die is gradually inserted into the positioning hole on the fixed die, the lower end of the positioning rod is contacted and extrudes the air bag in, the collision between the fixed mold and the movable mold is caused to affect the integrity of the parting surfaces of the movable mold and the fixed mold, so that the mold is damaged, meanwhile, in the process of mold closing, as the positioning groove is formed on the positioning rod, and the positioning bulge is arranged in the positioning hole, the positioning rod can be further positioned in the process of inserting the positioning rod into the positioning hole, so that the accuracy of the movement of the positioning rod is improved, the precision of the mold closing of the fixed mold and the movable mold is improved, the phenomenon that the parting surfaces of the fixed mold and the movable mold are collided due to the tiny dislocation between the fixed mold and the movable mold during mold closing is avoided, the mold is damaged, meanwhile, the phenomenon that the tiny dislocation between the movable mold and the fixed mold causes the flash defect on the surface of an injection molding product to affect the quality of the injection molding product is avoided, meanwhile, the air leakage hole arranged on the fixed mold can discharge the air in the, air is prevented from being doped in the injection molding piece, the qualification rate of the injection molding product is improved, meanwhile, air in the mold is discharged through the air leakage hole, dead angles in the injection molding product can be avoided, the quality of the injection molding product is influenced, and simultaneously, in the process that an injection molding head of the injection molding machine is contacted with and pressed on the lining, the lining gradually moves in the injection molding hole, the buffer rod is extruded when the lining moves, the buffer rod is pressed back to the movable cavity III, in the process that the buffer rod is pressed back to the third movable cavity by the lining, the lining moves slowly, so that the injection head of the injection molding machine is prevented from colliding with the fixed die due to the excessively high moving speed of the injection head, the injection head or the fixed die is prevented from being damaged, simultaneously, through the removal of bush, can increase and mould plastics the head and contact the bush to the displacement distance of the in-process of compressing tightly the bush, promote the first security of removing the in-process of moulding plastics, avoid moulding plastics and bump between head and the mould.

Preferably, a movable cavity II is formed in the fixed die; the central line of the movable cavity II is vertical to the bottom surface of the lower cavity on the fixed die; an ejector rod is arranged in the second movable cavity; the upper end of the ejector rod is positioned in the lower cavity, and the upper surface of the upper end of the ejector rod is flush with the bottom surface of the lower cavity; the ejector rod can move up and down in the second movable cavity; a first tension spring is arranged in the second movable cavity; two ends of the first tension spring are fixedly connected to the lower end of the ejector rod and the bottom surface of the second movable cavity respectively; an air passage is formed in the fixed die; two ends of the air passage are respectively communicated with the second movable cavity and the air bag; the air passage penetrates through the movable cavity III; the buffer rod is provided with a via hole; the air passages are communicated in the third movable cavity through the conducting holes; when the buffer rod is in the original position, the air passage is unblocked; in the process of closing the fixed die and the movable die, an injection head on the injection molding machine starts to move and contacts with the bushing; after the injection molding head contacts and compresses the bushing, the positioning rod just starts to contact the air bag;

when the injection molding machine works, after the fixed die and the movable die are matched, the air bag positioned in the positioning hole is extruded by the positioning rod, the pressure in the air bag rises, meanwhile, after the injection molding head is contacted with and presses the bushing, the positioning rod just begins to be contacted with the air bag, therefore, when the air bag begins to be compressed, the bushing is already pressed, the buffer rod in the third movable cavity is extruded by the bushing and is recovered into the third movable cavity, so that a conducting hole on the buffer rod and an air passage are staggered, the air passage is sealed, the ejector rod in the second movable cavity cannot stretch out, meanwhile, after the injection molding is completed, the injection molding head of the injection molding machine firstly begins to move towards the original position, after the injection molding head of the injection molding machine returns to the original position, the bushing returns to the original position under the action of the first spring, and simultaneously, after the bushing returns to the original position, the buffer rod in the, the buffer rod stretches out under the effect of spring two, after the buffer rod stretches out, conducting hole and air flue coincidence on the buffer rod, make the air flue switch on again, afterwards, the movable mould begins to separate with the cover half, simultaneously, through the air flue intercommunication between activity chamber two and the gasbag, the pressure in activity chamber two risees, promote the liftout rod and outwards stretch out, make the product after moulding plastics and mould separation, reduce the separation degree of difficulty between injection molding and the mould, the staff of being convenient for takes off the product of accomplishing production from the mould, simultaneously, after movable mould and cover half complete separation, get back to the normal position, the locating lever is not at the extrusion gasbag, the pressure in the activity chamber two with the gasbag intercommunication reduces, under the effect of extension spring one, the liftout rod is retrieved again in activity chamber two, wait for next time stretch out, separate product and mould.

Preferably, a baffle is arranged in the fixed die; the baffle is positioned on a passing path of the air leakage hole; the baffle is positioned right below the lower cavity and close to the bottom surface of the lower cavity; the baffle is provided with a through hole, and the air leakage hole can keep a conduction state through the through hole; a first movable cavity is formed in the baffle; the through hole penetrates through the first movable cavity; a sealing block is arranged in the first movable cavity; the through hole can be closed by the closing block, and the closing block can move freely in the first movable cavity; a bimetallic strip is arranged in the first movable cavity; the bimetallic strip and the sealing block are mutually connected through a flexible rod; when the bimetallic strip is not deformed, the through hole is kept smooth;

when the injection molding device works, the baffle is positioned right below the lower cavity and close to the lower cavity, when the mold is not subjected to injection molding production, the temperature sensed by the bimetallic strip in the first movable cavity in the baffle is relatively low, the bimetallic strip is not deformed, meanwhile, in the injection molding process, along with the gradual increase of plastic liquid filled in the mold, air in the mold is discharged from the air leakage hole, meanwhile, after the mold is completely covered by the plastic liquid filled in the mold, the temperature of the plastic liquid is relatively high, so that the temperature of the bimetallic strip in the baffle is increased, the bimetallic strip is deformed, the sealing block is pulled through the flexible rod to seal the through hole on the baffle, the air leakage hole is sealed, the phenomenon that the plastic liquid flows out through the air leakage hole in the subsequent pressurizing process for improving the quality of injection molded products after the mold is filled with the plastic liquid is avoided, and raw material waste is caused, and meanwhile, lead to the pressure boost process can not reach predetermined pressure, influence injection moulding product's quality, simultaneously, avoid the plastic liquid of liquid form to enter into and stop up the disappointing hole after the cooling in the hole of disappointing, influence the normal use of mould, simultaneously, after accomplishing the moulding plastics, the temperature in the mould descends, thereby make the temperature reduction of bimetallic strip, bimetallic strip reconversion, after bimetallic strip reconversion, bimetallic strip passes through the flexible rod and promotes the movement of closing block, relieve the closure to through-hole on the baffle, make the hole of disappointing switch on again.

Preferably, the upper surface of the fixed die is provided with a fixed groove; the lower surface of the movable die is provided with a fixed plate; the fixing plate can be inserted into the fixing groove; the fixing plates and the fixing grooves are respectively provided with a plurality of fixing grooves which are in one-to-one correspondence with each other; a cavity is formed in the fixed die; a fixed column is arranged in the cavity; the fixing column can be inserted into the fixing groove; after the fixing plate is inserted into the fixing groove, the fixing column can penetrate through a fixing hole correspondingly formed in the fixing plate; a third spring is arranged in the cavity; the spring is positioned between the fixed column and the cavity; a pull rope is arranged in the fixed die; two ends of the pull rope are fixedly connected to the fixed column and the buffer rod respectively; when the tail end of the buffer rod extends into the injection molding hole, the fixing column is retracted into the cavity;

when the injection molding machine works, after the fixed die and the movable die are matched, the fixed plate on the movable die is inserted into the fixed groove on the fixed die, after the fixed plate is inserted into the fixed groove, the fixed column in the cavity extends out and is inserted into the fixed hole on the fixed plate, so that the fixed plate is locked into the fixed groove, the problem that the mold locking force between the fixed die and the movable die is insufficient in the injection molding process is avoided, the product quality is influenced, meanwhile, when the injection molding head of the injection molding machine is contacted with and pressed against the bushing, the fixed plate is already inserted into the fixed groove and passes over the extending position of the fixed column in the fixed groove, therefore, the bushing is pressed by the injection molding head, the bushing presses the buffer rod back to the movable cavity III, the pull rope connected to the buffer rod is loosened, after the fixed column is released from being pulled, the fixed column extends outwards under the action of the spring III, and, therefore, the stretching action of the fixed column is blocked by the fixed plate until the fixed plate is completely inserted into the fixed groove, the fixed hole on the fixed plate is just opposite to the stretching position of the fixed column, the fixed column can be smoothly stretched out and inserted into the fixed hole, the fixed plate is locked, the movable mold is ensured to be in close contact with the fixed mold in the injection molding process, the mold locking force is prevented from being smaller than the injection pressure in the injection molding process, the movable mold is separated from the fixed mold, a gap is formed between the movable mold and the fixed mold, product burrs are caused, meanwhile, after the injection molding is completed, the injection molding head of the injection molding machine is separated from the bush firstly, the bush returns to the original position, the extrusion of the bush on the buffer rod is relieved, the buffer rod is enabled to stretch out again under the action of the spring II, the stretched pull rope is tightened, the fixed column is pulled back into the.

Preferably, a buffer cavity is formed in the positioning column; a movable rod is arranged in the buffer cavity; the lower end of the movable rod is provided with a flat plate, and the lower surface of the flat plate can be contacted with the air bag; the movable rod can move up and down in the buffer cavity, and the movable rod and the inner wall of the buffer cavity are sealed; the buffer cavity is communicated with the outside through a throttle valve; the buffer cavity is communicated with the outside through a one-way valve; the throttle valve and the one-way valve are mutually independent and are not communicated with each other;

when the movable die and the fixed die are assembled, the positioning rod assembly is inserted into the positioning hole, the buffer cavity is formed in the positioning rod, and the movable rod is installed in the buffer cavity, so that the movable rod is gradually contacted with the air bag at the bottom of the positioning hole in the process that the positioning rod is inserted into the positioning hole, the movable rod synchronously receives the reaction force of the air bag in the process that the movable rod extrudes the air bag, the movable rod withdraws towards the buffer cavity, the space in the buffer cavity is gradually reduced, the pressure is increased, the effect similar to the air bag is generated, the die assembling process of the movable die and the fixed die is buffered, the buffering effect is improved, meanwhile, the situation that the positioning rod directly and forcibly extrudes the air bag in the die assembling process to cause the air bag not to be deformed and cause the damage of the air bag is avoided, meanwhile, the pressure in the buffer cavity can be gradually released because the buffer cavity is communicated with, avoid accomplishing the compound die back at movable mould and cover half, still there is huge pressure in the cushion chamber, improve the demand of locking mould power between movable mould and the cover half, increase the mould and use the degree of difficulty, simultaneously, through the release rate who adjusts the choke valve, can guarantee at the compound die in-process, pressure in the cushion chamber is maintained at the certain limit throughout, avoids because the pressure in the cushion chamber is too high, leads to the unable compound die of movable mould and cover half or compound die time increase, influences production efficiency.

Preferably, an extension rod is arranged in the buffer cavity, and the central line of the extension rod is perpendicular to the central line of the positioning rod; the number of the extension rods is two, and the extension rods are symmetrically distributed in the buffer cavity; the locking rods are connected with each other through a tension spring; the movable rod cannot be contacted with the extension rod; one end of the extension rod, which is far away from the central line of the buffer cavity, can extend out of the positioning rod; an annular groove is formed in the side wall of the positioning hole; after the extension rod extends out of the positioning rod, the extension part of the extension rod is inserted into the annular groove;

when the injection molding machine works, in the process of closing the movable mold and the fixed mold, the pressure in the buffer cavity is increased, after the pressure in the buffer cavity is increased, the extension rod tends to extend out of the buffer cavity under the action of the pressure in the buffer cavity, after the positioning rod is completely inserted into the positioning hole, the extension part of the extension rod just aligns to the annular groove on the side wall of the positioning hole, so that the extension rod is inserted into the annular groove, the positioning rod is locked in the positioning hole, the firmness degree of the movable mold and the fixed mold after closing the mold is further improved, the phenomenon that a gap appears between the movable mold and the fixed mold during injection molding and the product quality is influenced is avoided, meanwhile, the discharge speed of the throttle valve is adjusted, after the injection molding is finished, the driving force of gas in the buffer cavity to the extension rod is just smaller than the pulling force of two pairs of extension rods between the extension rods, and the extension rod is prevented, the locking between the positioning rod and the positioning hole is released.

The invention has the following beneficial effects:

1. according to the injection mold, the positioning rod, the positioning hole, the positioning groove and the positioning protrusion are arranged, so that the accuracy of relative movement of the movable mold and the fixed mold can be guaranteed when the movable mold and the fixed mold are assembled, the movable mold and the fixed mold are prevented from being misplaced in the mold assembling process, the movable mold and the fixed mold are collided to cause damage to a parting surface on the movable mold and the fixed mold, the safety in the mold assembling process is improved, meanwhile, the movable mold can be buffered in the moving process in the mold assembling process through the arranged air bag and the arranged buffer cavity, the safety in the mold assembling process is improved, meanwhile, air in the mold can be discharged in the injection molding process through the air leakage hole arranged in the fixed mold, the phenomenon that air is doped in a product to influence the product quality is avoided, and meanwhile, the phenomenon that dead angle of the product is caused by.

2. According to the injection mold, the blocking piece, the bimetallic strip, the flexible rod and the sealing block are arranged, so that air in the mold can be smoothly discharged in the injection process, the phenomenon that air in the mold cannot be discharged and the quality of an injection product is influenced is avoided, meanwhile, under the action of the bimetallic strip, after the mold is filled with injection liquid, the sealing block is used for sealing the through hole in the blocking piece, and further the air leakage hole is blocked, the injection liquid in a mold cavity is prevented from leaking, the pressurization of the injection liquid in the mold is influenced, and the quality of the produced product is poor, meanwhile, the through hole in the baffle is sealed by the sealing block, so that the outflow of the injection liquid in the mold is prevented, the raw material waste is avoided, the air leakage hole is blocked by the solidified injection liquid, and the normal use of the mold is influenced.

3. According to the injection mold, the fixed groove, the fixed plate, the fixed column, the extension rod and the annular groove are arranged, so that the fixed plate and the extension rod piece can be mutually locked by the movable mold and the fixed mold after the movable mold and the fixed mold are assembled, and the phenomenon that a gap is formed between the movable mold and the fixed mold in the injection molding process to cause the flash of a product and influence on the quality of the product is avoided.

Drawings

The invention will be further explained with reference to the drawings.

FIG. 1 is a schematic structural view of a mold of the present invention;

FIG. 2 is a partial cross-sectional view of a stationary mold in a mold;

FIG. 3 is a schematic structural view of a movable mold in the mold;

FIG. 4 is a partial enlarged view of the positioning rod and the positioning hole of the mold;

FIG. 5 is an enlarged view of a portion of FIG. 1 at A;

FIG. 6 is an enlarged view of a portion of FIG. 1 at B;

FIG. 7 is an enlarged view of a portion of FIG. 1 at C;

FIG. 8 is an enlarged view of a portion of FIG. 2 at D;

FIG. 9 is an enlarged view of a portion E of FIG. 3;

in the figure: the fixed die comprises a fixed die 1, an injection molding hole 11, a fixed groove 12, a fixed column 121, a pull rope 122, a lower cavity 13, an air release hole 14, a baffle 141, a first movable cavity 142, a sealing block 143, a flexible rod 144, a bimetallic strip 145, an ejector rod 15, a second movable cavity 151, a first tension spring 152, a movable die 2, a positioning rod 21, an extension rod 211, a movable rod 212, a second tension spring 213, a positioning groove 214, an upper cavity 22, a fixed plate 23, a positioning hole 3, an air bag 31, an air channel 32, an annular groove 33, a positioning bulge 34, a bushing 4, a first spring 41, a buffer rod 42, a conducting hole 421, a second spring 422 and a third movable cavity 423.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.

As shown in fig. 1 to 9, the injection mold of the present invention includes a movable mold 2 and a fixed mold 1, wherein the fixed mold 1 is fixedly installed on an injection molding machine; the movable mould 2 is arranged on a movable part on the injection molding machine; the movable mold 2 and the fixed mold 1 can be attached to each other, so that the production of injection molding parts is completed; an upper cavity 22 is formed in the movable die 2; the upper cavity 22 is positioned on the side surface of the movable mold 2 close to the fixed mold 1; the movable die 2 is provided with a positioning rod 21; the fixed die 1 is provided with a lower cavity 13; the lower cavity 13 is positioned on the side surface of the fixed die 1 close to the movable die 2; the upper cavity 22 and the lower cavity 13 correspond to each other, and the edges of the upper cavity and the lower cavity are just attached; the fixed die 1 is provided with a positioning hole 3; the positioning rod 21 is inserted into the positioning hole 3; when the movable die 2 moves, the positioning rod 21 is not completely separated from the positioning hole 3; the side surface of the positioning rod 21 is provided with guide grooves distributed along the length direction of the positioning rod 21; a positioning bulge 34 is arranged on the inner wall of the positioning hole 3; the positioning projection 34 can be inserted into the guide groove, and the positioning projection 34 can move freely in the guide groove; an air bag 31 is arranged on the bottom surface of the positioning hole 3; the bottom surface of the positioning rod 21 can contact the air bag 31 and press the air bag 31; an injection molding hole 11 is formed in the fixed die 1; the outlet of the injection molding hole 11 is positioned on the bottom surface of a lower cavity 13 on the fixed die 1; the central line of the injection molding hole 11 is vertical to the bottom surface of the lower cavity 13; a bushing 4 is arranged in the injection molding hole 11; one end, far away from the fixed die 1, of the bushing 4 is located outside the fixed die 1, and a connector is arranged at one end, far away from the fixed die 1, of the bushing 4; a first spring 41 is arranged on the bushing 4; the first spring 41 is positioned between the connecting head on the bushing 4 and the fixed die 1; the bushing 4 is freely movable in the injection hole 11; a movable cavity III 423 is formed in the fixed die 1; the number of the three movable cavities 423 is two, and the three movable cavities are symmetrically distributed around the central line of the injection molding hole 11; a buffer rod 42 is arranged in the movable cavity III 423; the tail end of the buffer rod 42 extends out of the movable cavity III 423 and enters the injection molding hole 11; the tail end of the buffer rod 42 is arc-shaped and is in contact with one end of the lining 4 positioned in the fixed die 1; the buffer rod 42 does not exceed the center line of the bushing 4; a second spring 422 is arranged in the movable cavity III 423; the second spring 422 is positioned between the bottom surface of the third movable cavity 423 and the buffer rod 42; an air release hole 14 is formed in the fixed die 1; the air leakage hole 14 communicates the lower cavity 13 with the outside;

when the injection molding machine works, the fixed die 1 and the movable die 2 are correctly installed on the injection molding machine, when the production is started, the movable die 2 is controlled to slowly move towards the fixed die 1 until the fixed die 1 and the movable die are contacted with each other, the die assembly is completed, the upper die cavity 22 and the lower die cavity 13 are connected with each other to form the shape of a product, meanwhile, after the die assembly of the fixed die 1 and the movable die 2 is completed, the injection head of the injection molding machine is controlled to be contacted with and pressed on the lining 4, the communication between the injection molding machine and the injection molding hole 11 is completed, then, the injection molding process of the injection molding machine is controlled to start, the production of the injection molding product is completed, meanwhile, in the die assembly process of the fixed die 1 and the movable die 2, the positioning rod 21 on the movable die 2 is gradually inserted into the positioning hole 3 on the fixed die 1, the lower end of the positioning rod 21 is contacted with and, when the fixed die 1 and the movable die 2 are contacted with each other, the relative speed is too high, so that the fixed die 1 and the movable die 2 are collided, the integrity of the parting surfaces of the movable die 2 and the fixed die 1 is influenced, the die is damaged, meanwhile, in the die assembling process, because the positioning groove 214 is formed in the positioning rod 21 and the positioning bulge 34 is arranged in the positioning hole 3, the positioning rod 21 can be further positioned in the process that the positioning rod 21 is inserted into the positioning hole 3, the movement accuracy of the positioning rod 21 is improved, so that the accuracy in die assembling of the fixed die 1 and the movable die 2 is improved, the situation that the parting surfaces of the fixed die 1 and the movable die 2 are collided due to the existence of micro dislocation between the fixed die 1 and the movable die 2 when the die is assembled is avoided, the die is damaged, meanwhile, the situation that the surface of an injection product has a flash defect due to the existence of the micro dislocation between the movable, when the injection molding machine performs injection molding in a mold after the mold closing, air in the upper cavity 22 and the lower cavity 13 is exhausted, air doping in an injection molding part is avoided, the qualification rate of an injection molding product is improved, meanwhile, air in the mold is exhausted through the air release hole 14, dead angles in the injection molding product can be avoided, the quality of the injection molding product is influenced, meanwhile, in the process that an injection molding head of the injection molding machine contacts and presses the lining 4, the lining 4 gradually moves in the injection molding hole 11, the buffer rod 42 is extruded when the lining 4 moves, the buffer rod 42 is pressed back to the movable cavity three 423, in the process that the lining 4 presses the buffer rod 42 back to the movable cavity three 423, the lining 4 moves slowly, the phenomenon that the injection molding head of the injection molding machine moves too fast to cause collision when the injection molding head contacts with the fixed mold 1 to cause damage to the injection molding head or the fixed mold 1 is avoided, and meanwhile, through the movement of the lining 4, can increase and mould plastics the head and contact bush 4 to the displacement distance who compresses tightly the in-process of bush 4, promote the first security that removes the in-process of moulding plastics, avoid moulding plastics and bump between head and the mould.

As an embodiment of the invention, a second movable cavity 151 is formed in the fixed die 1; the central line of the second movable cavity 151 is vertical to the bottom surface of the lower cavity 13 on the fixed die 1; the second movable cavity 151 is internally provided with an ejector rod 15; the upper end of the ejector rod 15 is positioned in the lower cavity 13, and the upper surface of the upper end of the ejector rod 15 is flush with the bottom surface of the lower cavity 13; the ejector rod 15 can move up and down in the second movable cavity 151; a first tension spring 152 is arranged in the second movable cavity 151; two ends of the first tension spring 152 are fixedly connected to the lower end of the ejector rod 15 and the bottom surface of the second movable cavity 151 respectively; an air passage 32 is formed in the fixed die 1; two ends of the air passage 32 are respectively communicated with the second movable cavity 151 and the air bag 31; the air passage 32 penetrates through the movable cavity III 423; the buffer rod 42 is provided with a through hole 421; the air passage 32 is communicated in the movable cavity III 423 through the communicating hole 421; when the buffer rod 42 is in the original position, the air passage 32 is unblocked; in the process of closing the fixed die 1 and the movable die 2, an injection head on the injection molding machine starts to move and is in contact with the bush 4; after the injection head contacts and presses the bush 4, the positioning rod 21 just starts to contact the air bag 31;

during operation, after the fixed die 1 and the movable die 2 are matched, the air bag 31 in the positioning hole 3 is extruded by the positioning rod 21, the pressure in the air bag 31 is increased, meanwhile, after the injection head contacts and presses the bush 4, the positioning rod 21 just starts to contact the air bag 31, therefore, when the air bag 31 starts to be compressed, the bush 4 is already pressed, the buffer rod 42 in the movable cavity three 423 is extruded and retracted into the movable cavity three 423 by the bush 4, the through hole 421 on the buffer rod 42 is staggered with the air passage 32, the air passage 32 is sealed, the ejector rod 15 in the movable cavity two 151 cannot be extended, meanwhile, after the injection molding is completed, the injection head of the injection molding machine firstly starts to move to the original position, after the injection head of the injection molding machine returns to the original position, the bush 4 returns to the original position under the action of the spring one 41, and simultaneously, after the bush 4 returns to the original position, the buffer rod 42 in the movable cavity III 423 is not extruded by the bushing 4, the buffer rod 42 extends out under the action of the spring II 422, after the buffer rod 42 extends out, the through hole 421 on the buffer rod 42 is overlapped with the air passage 32 to enable the air passage 32 to be conducted again, then the movable mold 2 starts to be separated from the fixed mold 1, meanwhile, the movable cavity II 151 is communicated with the air bag 31 through the air passage 32, the pressure in the movable cavity II 151 is increased to push the ejector rod 15 to extend outwards, the injection molded product is separated from the mold, the separation difficulty between the injection molded product and the mold is reduced, a worker can conveniently take the produced product off from the mold, meanwhile, after the movable mold 2 is completely separated from the fixed mold 1 and returns to the original position, the positioning rod 21 is not extruding the air bag 31, the pressure in the movable cavity II 151 communicated with the air bag 31 is reduced, and the ejector rod 15 is retracted back into the movable cavity II 151 under the action of the tension spring I152, and waiting for the next extending, and separating the product from the mold.

As an embodiment of the present invention, a baffle 141 is installed in the fixed mold 1; the baffle 141 is positioned on the passing path of the air leakage hole 14; the baffle 141 is positioned right below the lower cavity 13 and close to the bottom surface of the lower cavity 13; a through hole is formed in the baffle 141, and the air leakage hole 14 can be kept in a conduction state through the through hole; a first movable cavity 142 is formed in the baffle 141; the through hole penetrates through the first movable cavity 142; a sealing block 143 is arranged in the first movable cavity 142; the through hole can be closed by a closing block 143, and the closing block 143 can move freely in the first movable cavity 142; a bimetallic strip 145 is arranged in the first movable cavity 142; the bimetallic strip 145 and the closing block 143 are connected with each other through a flexible rod 144; when the bimetallic strip 145 is not deformed, the through hole is kept smooth;

when the injection molding machine works, because the baffle plate 141 is positioned right below the lower cavity 13 and close to the lower cavity 13, when the injection molding production is not carried out on the mold, the temperature sensed by the bimetallic strip 145 in the first movable cavity 142 in the baffle plate 141 is relatively low, the bimetallic strip 145 is not deformed, meanwhile, in the injection molding process, along with the gradual increase of plastic liquid filled in the mold, air in the mold is discharged from the air leakage hole 14, meanwhile, after the mold is completely covered by the plastic liquid filled in the mold, because the temperature of the plastic liquid is relatively high, the temperature of the bimetallic strip 145 in the baffle plate 141 is increased, the bimetallic strip 145 is deformed, so that the flexible rod 144 pulls the sealing block 143 to seal the through hole on the baffle plate 141, the air leakage hole 14 is sealed, and after the mold is filled with the plastic liquid, the plastic liquid is prevented from flowing out through the air leakage hole 14 in the subsequent pressurizing process for improving the quality of injection molding products, the raw materials are wasted, meanwhile, the pressurizing process cannot reach the preset pressure, the quality of an injection molding product is influenced, meanwhile, the liquid plastic liquid is prevented from entering the air release hole 14 to be cooled and then blocking the air release hole 14, the normal use of the mold is influenced, meanwhile, after the injection molding is completed, the temperature in the mold is reduced, so that the temperature of the bimetallic strip 145 is reduced, the bimetallic strip 145 is restored to the original state, after the bimetallic strip 145 is restored to the original state, the bimetallic strip 145 pushes the sealing block 143 to move through the flexible rod 144, the sealing of the through hole in the baffle plate 141 is released, and the air release hole 14 is conducted again.

As an embodiment of the invention, a fixed groove 12 is formed on the upper surface of the fixed mold 1; a fixed plate 23 is arranged on the lower surface of the movable mold 2; the fixing plate 23 can be inserted into the fixing groove 12; a plurality of fixing plates 23 and fixing grooves 12 are arranged and are in one-to-one correspondence with each other; a cavity is formed in the fixed die 1; a fixing column 121 is arranged in the cavity; the fixing post 121 can be inserted into the fixing groove 12; after the fixing plate 23 is inserted into the fixing groove 12, the fixing column 121 can pass through a fixing hole correspondingly arranged on the fixing plate 23; a third spring is arranged in the cavity; the third spring is positioned between the fixed column 121 and the cavity; a pull rope 122 is arranged in the fixed die 1; two ends of the pull rope 122 are respectively fixedly connected to the fixed column 121 and the buffer rod 42; when the tail end of the buffer rod 42 extends out of the injection molding hole 11, the fixed column 121 is retracted into the cavity;

when the injection molding machine works, after the fixed die 1 and the movable die 2 are matched, the fixed plate 23 on the movable die 2 is inserted into the fixed groove 12 on the fixed die 1, after the fixed plate 23 is inserted into the fixed groove 12, the fixed column 121 in the cavity extends out and is inserted into the fixed hole on the fixed plate 23, so that the fixed plate 23 is locked into the fixed groove 12, the problem that the product has flash due to insufficient mold locking force between the fixed die 1 and the movable die 2 in the injection molding process is avoided, the product quality is influenced, meanwhile, when the injection head of the injection molding machine is contacted and pressed to the bush 4, the fixed plate 23 is already inserted into the fixed groove 12 and passes over the extending position of the fixed column 121 in the fixed groove 12, therefore, the bush 4 is pressed by the injection head, the cushion rod 42 is pressed back to the movable cavity three 423 by the bush 4, the pull rope 122 connected to the cushion rod 42 is loosened, after the fixed column 121 is released from being pulled, meanwhile, because the fixed plate 23 already crosses the extending position of the fixed column 121, the extending action of the fixed column 121 is blocked by the fixed plate 23, until the fixed plate 23 is completely inserted into the fixed slot 12, and the fixed hole on the fixed plate 23 is just opposite to the extending position of the fixed column 121, the fixed column 121 can not smoothly extend and be inserted into the fixed hole, the fixed plate 23 is locked, so that the movable mold 2 is ensured to be in close contact with the fixed mold 1 in the injection molding process, the mold locking force is prevented from being smaller than the injection molding pressure in the injection molding process, the movable mold 2 is separated from the fixed mold 1, a gap is generated between the movable mold 2 and the fixed mold 1, and the product is flapped, meanwhile, after the injection molding is completed, the injection molding head of the injection molding machine is firstly separated from the bush 4, the bush 4 is returned to the original position, the extrusion of the bush 4 on the buffer rod 42 is, the fixed column 121 is pulled back into the cavity through the action of the pull rope 122, the fixed plate 23 is unlocked, and the movable die 2 is conveniently separated from the fixed die 1.

As an embodiment of the invention, a buffer cavity is formed in the positioning column; a movable rod 212 is arranged in the buffer cavity; the lower end of the movable rod 212 is provided with a flat plate, and the lower surface of the flat plate can be contacted with the air bag 31; the movable rod 212 can move up and down in the buffer cavity, and the seal is kept between the movable rod 212 and the inner wall of the buffer cavity; the buffer cavity is communicated with the outside through a throttle valve; the buffer cavity is communicated with the outside through a one-way valve; the throttle valve and the one-way valve are mutually independent and are not communicated with each other;

during operation, in the process of closing the movable mold 2 and the fixed mold 1, the positioning rod 21 assembly is inserted into the positioning hole 3, because the positioning rod 21 is internally provided with the buffer cavity, and the movable rod 212 is installed in the buffer cavity, in the process of inserting the positioning rod 21 into the positioning hole 3, the movable rod 212 gradually contacts the air bag 31 at the bottom of the positioning hole 3, in the process of extruding the air bag 31 by the movable rod 212, the movable rod 212 synchronously receives the reaction force of the air bag 31, so that the movable rod 212 is retracted towards the buffer cavity, the space in the buffer cavity is gradually reduced, the pressure is increased, the effect similar to the air bag 31 is generated, the closing process of the movable mold 2 and the fixed mold 1 is buffered, the buffering effect is improved, meanwhile, the situation that in the closing process, the positioning rod 21 directly and forcibly extrudes the air bag 31 to cause no time for deformation of the air bag 31, the air bag 31 is damaged is caused, and meanwhile, the, pressure in the cushion chamber can be released gradually, avoid accomplishing the compound die back at movable mould 2 and cover half 1, still there is huge pressure in the cushion chamber, improve the demand of mode locking power between movable mould 2 and the cover half 1, increase the mould and use the degree of difficulty, and simultaneously, release rate through adjusting the choke valve, can guarantee at the compound die in-process, pressure in the cushion chamber remains throughout in the certain limit, avoid because the pressure in the cushion chamber is too high, lead to the unable compound die of movable mould 2 and cover half 1 or compound die time increase, influence production efficiency.

As an embodiment of the present invention, an extension bar 211 is installed in the buffer cavity, and a center line of the extension bar 211 is perpendicular to a center line of the positioning bar 21; the number of the extension rods 211 is two, and the extension rods are symmetrically distributed in the buffer cavity; the locking rods are connected with each other through a second tension spring 213; the movable rod 212 cannot contact with the protruding rod 211; one end of the extension rod 211, which is far away from the central line of the buffer cavity, can extend out of the positioning rod 21; an annular groove 33 is formed in the side wall of the positioning hole 3; after the extension bar 211 extends out of the positioning bar 21, the extending part of the extension bar 211 is inserted into the annular groove 33;

when the injection molding machine works, in the process of closing the movable mold 2 and the fixed mold 1, the pressure in the buffer cavity is increased, after the pressure in the buffer cavity is increased, the extending rod 211 tends to extend out of the buffer cavity under the action of the pressure in the buffer cavity, after the positioning rod 21 is completely inserted into the positioning hole 3, the extending part of the extending rod 211 is just aligned with the annular groove 33 on the side wall of the positioning hole 3, so that the extending rod 211 is inserted into the annular groove 33, the positioning rod 21 is locked in the positioning hole 3, the firmness after the movable mold 2 and the fixed mold 1 are closed is further improved, a gap is prevented from being formed between the movable mold 2 and the fixed mold 1 during injection molding, the product quality is influenced, meanwhile, the driving force of gas in the buffer cavity to the extending rod 211 is just smaller than the pulling force of the tension spring II 213 between the extending rods 211 after the injection molding is finished by adjusting the discharge speed of the throttle valve, the extension rod 211 has been retracted into the buffer chamber by the second extension spring 213, and the lock between the positioning rod 21 and the positioning hole 3 is released.

The specific working process is as follows:

when the injection molding machine works, the fixed die 1 and the movable die 2 are correctly installed on the injection molding machine, when the production is started, the movable die 2 is controlled to slowly move towards the fixed die 1 to complete die assembly, meanwhile, after the die assembly of the fixed die 1 and the movable die 2 is completed, the injection head of the injection molding machine is controlled to be contacted and pressed on the bush 4 to complete the communication between the injection molding machine and the injection molding hole 11, meanwhile, in the process of die assembly of the fixed die 1 and the movable die 2, the positioning rod 21 on the movable die 2 is gradually inserted into the positioning hole 3 on the fixed die 1, the lower end of the positioning rod 21 is contacted and pressed on the air bag 31 in the positioning hole 3, meanwhile, in the process of die assembly, as the positioning groove 214 is formed on the positioning rod 21, the positioning bulge 34 is arranged in the positioning hole 3 to position the positioning rod 21, and meanwhile, the air release hole 14 arranged on the fixed die 1 can exhaust the air in, meanwhile, in the process that the injection head of the injection molding machine is contacted and pressed to the liner 4, the liner 4 gradually moves in the injection molding hole 11, and the buffer rod 42 is extruded when the liner 4 moves, so that the buffer rod 42 is pressed back to the movable cavity III 423; after the fixed die 1 and the movable die 2 are matched, the air bag 31 in the positioning hole 3 is extruded by the positioning rod 21, the pressure in the air bag 31 is increased, meanwhile, after the injection head contacts and presses the bush 4, the positioning rod 21 just starts to contact the air bag 31, when the air bag 31 starts to be compressed, the bush 4 is already pressed, the buffer rod 42 in the movable cavity three 423 is extruded and retracted into the movable cavity three 423 by the bush 4, so that the through hole 421 on the buffer rod 42 is staggered with the air passage 32, the air passage 32 is sealed, meanwhile, after the injection molding is finished, the injection head of the injection molding machine firstly starts to move to the home position, after the injection head of the injection molding machine returns to the home position, the bush 4 returns to the home position under the action of the spring one 41, and simultaneously, after the bush 4 returns to the home position, the buffer rod 42 in the movable cavity three 423 is not extruded by the bush 4, the buffer rod 42 extends under the action of the second spring 422, after the buffer rod 42 extends, the through hole 421 on the buffer rod 42 is overlapped with the air passage 32, so that the air passage 32 is conducted again, then the movable die 2 is separated from the fixed die 1, meanwhile, the second movable cavity 151 is communicated with the air bag 31 through the air passage 32, the pressure in the second movable cavity 151 is increased, the ejector rod 15 is pushed to extend outwards, meanwhile, after the movable die 2 is completely separated from the fixed die 1 and returns to the original position, the positioning rod 21 does not extrude the air bag 31, the pressure in the second movable cavity 151 communicated with the air bag 31 is reduced, and the ejector rod 15 is retracted into the second movable cavity 151 under the action of the first tension spring 152; because the baffle 141 is located right below the lower cavity 13 and close to the lower cavity 13, when the mold is not subjected to injection molding production, the temperature sensed by the bimetal 145 in the first movable cavity 142 in the baffle 141 is relatively low, the bimetal 145 is not deformed, meanwhile, after the mold is completely covered by the filled plastic liquid, the temperature of the bimetal 145 in the baffle 141 is increased, so that the bimetal 145 is deformed, the closing block 143 is pulled through the flexible rod 144, the through hole on the baffle 141 is closed, so that the air release hole 14 is closed, meanwhile, after the injection molding is completed, the temperature in the mold is reduced, so that the temperature of the bimetal 145 is reduced, the bimetal 145 is restored to the original state, and after the bimetal 145 is restored to the original state, the bimetal 145 pushes the closing block 143 to move through the flexible rod 144, so that the closing of the through hole on the baffle 141 is released; when the fixed die 1 and the movable die 2 are matched, the fixed plate 23 on the movable die 2 is inserted into the fixed slot 12 on the fixed die 1, the fixed column 121 in the cavity is inserted into the fixed hole on the fixed plate 23 after the fixed plate 23 is inserted into the fixed slot 12, and at the same time, when the injection head of the injection molding machine is contacted and pressed against the bush 4, the fixed plate 23 is already inserted into the fixed slot 12 and crosses the extending position of the fixed column 121 in the fixed slot 12, therefore, the bush 4 is pressed against the bush 4, the buffer rod 42 is pressed back into the movable cavity three 423 by the bush 4, the pull rope 122 connected to the buffer rod 42 is loosened, after the pulling of the fixed column 121 is released, the fixed column 121 is extended outwards under the action of the spring three, and at the same time, because the fixed plate 23 has crossed the extending position of the fixed column 121, the extending action of the fixed column 121 is blocked by the fixed plate 23 until the, after the fixing hole on the fixing plate 23 is over against the extending part of the fixing column 121, the fixing column 121 can extend out and be inserted into the fixing hole, meanwhile, after the injection molding is completed, the injection molding head of the injection molding machine is firstly separated from the bushing 4, the bushing 4 is enabled to return to the original position, the extrusion of the bushing 4 on the buffer rod 42 is released, so that the buffer rod 42 extends out again under the action of the second spring 422, the stretching rope 122 is tightened by the buffer rod 42 which extends out again, the fixing column 121 is pulled back into the cavity through the action of the stretching rope 122, and the fixing plate 23 is unlocked; in the process of closing the movable die 2 and the fixed die 1, the positioning rod 21 is inserted into the positioning hole 3, and as the positioning rod 21 is internally provided with the buffer cavity and the movable rod 212 is arranged in the buffer cavity, the movable rod 212 is gradually contacted with the air bag 31 at the bottom of the positioning hole 3 in the process of inserting the positioning rod 21 into the positioning hole 3, and the movable rod 212 is synchronously subjected to the reaction force of the air bag 31 in the process of extruding the air bag 31 by the movable rod 212, so that the movable rod 212 is retracted towards the buffer cavity, the space in the buffer cavity is gradually reduced, the pressure is increased, and the effect similar to the air bag 31 is generated; when the movable die 2 and the fixed die 1 are matched, the pressure in the buffer cavity is increased, after the pressure in the buffer cavity is increased, the extending rod 211 tends to extend out of the buffer cavity under the action of the pressure in the buffer cavity, and after the positioning rod 21 is completely inserted into the positioning hole 3, the extending part of the extending rod 211 is just aligned with the annular groove 33 on the side wall of the positioning hole 3, so that the extending rod 211 is inserted into the annular groove 33.

The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. The utility model provides an injection mold, includes movable mould (2) and cover half (1), its characterized in that: the fixed die (1) is fixedly arranged on an injection molding machine; the movable mould (2) is arranged on a movable part on the injection molding machine; the movable mold (2) and the fixed mold (1) can be attached to each other, so that the production of injection molding parts is completed; an upper cavity (22) is formed in the movable die (2); the upper cavity (22) is positioned on the side surface of the movable mould (2) close to the fixed mould (1); a positioning rod (21) is arranged on the movable die (2); the fixed die (1) is provided with a lower cavity (13); the lower cavity (13) is positioned on the side surface of the fixed die (1) close to the movable die (2); the upper cavity (22) and the lower cavity (13) correspond to each other, and the edges of the upper cavity and the lower cavity are just attached to each other; the fixed die (1) is provided with a positioning hole (3); the positioning rod (21) is inserted into the positioning hole (3); when the movable die (2) moves, the positioning rod (21) is not completely separated from the positioning hole (3); the side surface of the positioning rod (21) is provided with guide grooves distributed along the length direction of the positioning rod (21); a positioning bulge (34) is arranged on the inner wall of the positioning hole (3); the positioning projection (34) can be inserted into the guide groove, and the positioning projection (34) can move freely in the guide groove; an air bag (31) is arranged on the bottom surface of the positioning hole (3); the bottom surface of the positioning rod (21) can contact the air bag (31) and press the air bag (31); an injection molding hole (11) is formed in the fixed die (1); the outlet of the injection molding hole (11) is positioned on the bottom surface of a lower cavity (13) on the fixed die (1); the central line of the injection molding hole (11) is vertical to the bottom surface of the lower cavity (13); a bushing (4) is arranged in the injection molding hole (11); one end, far away from the fixed die (1), of the bushing (4) is located outside the fixed die (1), and a connector is arranged at one end, far away from the fixed die (1), of the bushing (4); a first spring (41) is mounted on the bushing (4); the first spring (41) is positioned between the connector on the bushing (4) and the fixed die (1); the bushing (4) can move freely in the injection hole (11); a movable cavity III (423) is formed in the fixed die (1); the number of the three movable cavities (423) is two, and the three movable cavities are symmetrically distributed around the central line of the injection molding hole (11); a buffer rod (42) is arranged in the third movable cavity (423); the tail end of the buffer rod (42) extends out of the movable cavity III (423) and enters the injection molding hole (11); the tail end of the buffer rod (42) is arc-shaped and is in contact with one end, located in the fixed die (1), of the lining (4); the buffer rod (42) does not exceed the central line of the bushing (4); a second spring (422) is arranged in the third movable cavity (423); the second spring (422) is positioned between the bottom surface of the third movable cavity (423) and the buffer rod (42); an air leakage hole (14) is formed in the fixed die (1); the air leakage hole (14) is used for communicating the lower cavity (13) with the outside.

2. An injection mold according to claim 1, characterized in that: a second movable cavity (151) is formed in the fixed die (1); the central line of the second movable cavity (151) is vertical to the bottom surface of the lower cavity (13) on the fixed die (1); an ejector rod (15) is arranged in the second movable cavity (151); the upper end of the ejector rod (15) is positioned in the lower cavity (13), and the upper surface of the upper end of the ejector rod (15) is flush with the bottom surface of the lower cavity (13); the ejection rod (15) can move up and down in the second movable cavity (151); a first tension spring (152) is arranged in the second movable cavity (151); two ends of the first tension spring (152) are fixedly connected to the lower end of the ejector rod (15) and the bottom surface of the second movable cavity (151) respectively; an air passage (32) is formed in the fixed die (1); two ends of the air passage (32) are respectively communicated with the second movable cavity (151) and the air bag (31); the air passage (32) penetrates through the movable cavity III (423); a through hole (421) is formed in the buffer rod (42); the air passages (32) are communicated in the movable cavity III (423) through the communicating holes (421); when the buffer rod (42) is in the original position, the air channel (32) is unblocked; in the process of closing the fixed die (1) and the movable die (2), an injection molding head on the injection molding machine starts to move and is in contact with the bushing (4) in the same way; after the injection molding head contacts and presses the bush (4), the positioning rod (21) just starts to contact the air bag (31).

3. An injection mold according to claim 1, characterized in that: a baffle (141) is arranged in the fixed die (1); the baffle (141) is positioned on the passing path of the air leakage hole (14); the baffle (141) is positioned right below the lower cavity (13) and close to the bottom surface of the lower cavity (13); the baffle (141) is provided with a through hole, and the air leakage hole (14) can keep a conduction state through the through hole; a first movable cavity (142) is formed in the baffle (141); the through hole penetrates through the first movable cavity (142); a sealing block (143) is arranged in the first movable cavity (142); the through hole can be closed by a closing block (143), and the closing block (143) can move freely in the first movable cavity (142); a bimetallic strip (145) is arranged in the first movable cavity (142); the bimetallic strip (145) and the closing block (143) are connected with each other through a flexible rod (144); when the bimetallic strip (145) is not deformed, the through hole is kept open.

4. An injection mould according to claim 2, characterized in that: a fixed groove (12) is formed in the upper surface of the fixed die (1); a fixed plate (23) is arranged on the lower surface of the movable mold (2); the fixing plate (23) can be inserted into the fixing groove (12); a plurality of fixing plates (23) and a plurality of fixing grooves (12) are arranged and are in one-to-one correspondence with each other; a cavity is formed in the fixed die (1); a fixing column (121) is arranged in the cavity; the fixing column (121) can be inserted into the fixing groove (12); after the fixing plate (23) is inserted into the fixing groove (12), the fixing column (121) can penetrate through a fixing hole correspondingly formed in the fixing plate (23); a third spring is arranged in the cavity; the spring is positioned between the fixed column (121) and the cavity; a pull rope (122) is arranged in the fixed die (1); two ends of the pull rope (122) are fixedly connected to the fixed column (121) and the buffer rod (42) respectively; when the tail end of the buffer rod (42) extends into the injection molding hole (11), the fixing column (121) is retracted into the cavity.

5. An injection mold according to claim 1, characterized in that: a buffer cavity is formed in the positioning column; a movable rod (212) is arranged in the buffer cavity; the lower end of the movable rod (212) is provided with a flat plate, and the lower surface of the flat plate can be contacted with the air bag (31); the movable rod (212) can move up and down in the buffer cavity, and sealing is kept between the movable rod (212) and the inner wall of the buffer cavity; the buffer cavity is communicated with the outside through a throttle valve; the buffer cavity is communicated with the outside through a one-way valve; the throttle valve and the one-way valve are mutually independent and are not communicated with each other.

6. An injection mold according to claim 5, wherein: an extension rod (211) is arranged in the buffer cavity, and the central line of the extension rod (211) is perpendicular to the central line of the positioning rod (21); the two extension rods (211) are symmetrically distributed in the buffer cavity; the locking rods are connected with each other through a second tension spring (213); the movable rod (212) cannot be contacted with the extension rod (211); one end, far away from the central line of the buffer cavity, of the extension rod (211) can extend out of the positioning rod (21); an annular groove (33) is formed in the side wall of the positioning hole (3); after the extension rod (211) extends out of the positioning rod (21), the extension part of the extension rod (211) is inserted into the annular groove (33).