CN108327179B

CN108327179B - Nitrogen nozzle assembly used in gas-assisted mold

Info

Publication number: CN108327179B
Application number: CN201810091872.1A
Authority: CN
Inventors: 欧忠飞
Original assignee: Zhejiang Geely Holding Group Co Ltd; Geely Automobile Research Institute Ningbo Co Ltd
Current assignee: Zhejiang Geely Holding Group Co Ltd; Geely Automobile Research Institute Ningbo Co Ltd
Priority date: 2018-01-30
Filing date: 2018-01-30
Publication date: 2020-07-24
Anticipated expiration: 2038-01-30
Also published as: CN108327179A

Abstract

The invention provides a nitrogen nozzle assembly used in a gas-assisted mold, wherein the gas-assisted mold is provided with an insert for containing the nitrogen nozzle assembly, the nitrogen nozzle assembly is arranged in the insert and comprises: the air needle core sleeve is embedded in the mounting part of the insert, the wall surface surrounded by the outer surface of the air needle core sleeve is matched with the inner wall surface of the mounting part, and a containing space is limited in the air needle core sleeve; the gas needle core is fixed in the accommodating space and is provided with a gas channel communicated with the gas channel and the flow channel, the gas channel is used for introducing gas from the outside, and the flow channel is a flow channel after the gas enters a cavity in the gas-assisted mold; the gas channel is provided with a gas inlet end connected with the gas channel and a gas outlet end connected with the flow channel, and the gas needle core exceeds the surface of the insert at the gas outlet end by a first preset length at one side of the gas outlet end. The invention ensures the sealing performance of the nitrogen nozzle in the working process, is convenient to disassemble, assemble and maintain on the gas-assisted die, and ensures that the sealing ring in the nitrogen nozzle is not damaged.

Description

Nitrogen nozzle assembly used in gas-assisted mold

Technical Field

The invention relates to the technical field of gas-assisted molding, in particular to a nitrogen nozzle assembly for a gas-assisted mold.

Background

Gas-assisted molding has recently been increasingly used. Gas-assisted molding (GIM) is a novel injection molding technology which is characterized in that high-pressure inert gas is injected when plastic is properly filled into a cavity (90-99%), the gas pushes molten plastic to continuously fill the cavity, and the gas pressure maintaining process is used for replacing the plastic pressure maintaining process. The mold typically used in gas-assisted molding is a gas-assisted mold. In the gas-assisted forming process, the gas functions in two ways: firstly, driving the plastic to flow to continuously fill the die cavity; and secondly, the hollow pipeline is formed, the plastic consumption is reduced, the weight of the finished product is reduced, the cooling time is shortened, and the pressure maintaining pressure is transmitted more effectively. In general, a nitrogen nozzle assembly is used as a main device for air inlet in gas-assisted molding. Therefore, the structure and performance of the nitrogen nozzle assembly as an air inlet device for air in the gas-assisted forming process directly affect the final quality of the gas-assisted forming.

The nitrogen nozzle in the prior art is generally installed in a thread fastening mode, and the problems of insufficient hole machining precision and insufficient thread perpendicularity during tapping can exist, so that the situation of air leakage is caused after the nitrogen nozzle is installed. What's more, the phenomenon that the installation does not advance or the installation back card is dead in the nitrogen gas nozzle installation among the prior art, the change and the maintenance of nitrogen gas nozzle in later stage of being not convenient for. Moreover, when the nitrogen nozzle is installed in the prior art, the sealing ring on the nitrogen nozzle always breaks, so that the sealing ring cannot have practical effect in the subsequent use process.

Disclosure of Invention

One object of the present invention is to provide a nitrogen nozzle assembly for use in a gas-assisted mold, which ensures the sealing performance of the nitrogen nozzle during operation and avoids any gas leakage.

A further object of the present invention is to enable the nitrogen nozzle to be easily removed, installed and maintained on a gas-assisted mold, and to ensure that the seal ring is not damaged during installation.

In particular, the present invention provides a nitrogen gas nozzle assembly for use in a gas-assisted mold having an insert disposed therein for receiving the nitrogen gas nozzle assembly, the nitrogen gas nozzle assembly being disposed in the insert and comprising: the gas needle core sleeve is embedded in the mounting part of the insert, the wall surface surrounded by the outer surface of the gas needle core sleeve is matched with the inner wall surface of the mounting part, and a containing space is limited in the gas needle core sleeve; the gas needle core is fixed in the accommodating space and is provided with a gas channel communicated with a gas channel and a flow channel, the gas channel is used for introducing gas from the outside, and the flow channel is a flow channel after the gas enters a cavity in the gas-assisted mold; the gas channel is provided with a gas inlet end connected with the gas channel and a gas outlet end connected with the flow channel, and the gas needle core exceeds the surface of the insert at one side of the gas outlet end by a first preset length.

Further, the gas-assisted die is provided with a fixed die and a movable die which can be separated, the fixed die is provided with the air passage, the movable die is provided with the flow passage, the insert is a fixed die insert, the fixed die insert is fixed in the fixed die, and the gas needle core, the gas needle core sleeve and the fixed die insert are hermetically attached to one side of the gas inlet end of the fixed die so as to prevent gas from leaking when entering the gas passage from the air passage.

Furthermore, the gas-assisted die is provided with a fixed die and a movable die which can be separated from each other, the fixed die is provided with the runner, the movable die is provided with the air passage, the insert is a movable die insert, the movable die insert is fixed in the movable die, and the air needle core, the air needle core sleeve and the movable die insert are hermetically attached to the movable die on one side of the air inlet end so as to prevent gas from leaking when entering the gas passage from the air passage.

Further, the nitrogen nozzle assembly further comprises: the sealing ring is arranged on one side of the air inlet end and arranged between the air needle core sleeve and the fixed die, so that the sealing ring can seal a gap between the air needle core sleeve and the fixed die to prevent gas from entering the gas channel from overflowing from the gap.

Furthermore, the gas needle core sleeve is provided with a sealing groove which is arranged around the circumference of the gas channel on one side of the gas inlet end, and the sealing ring is arranged in the sealing groove.

Further, the air needle core is sleeved on one side of the air outlet end and exceeds the surface of the insert on one side of the air outlet end by a second preset length.

Further, the first predetermined length is greater than the second predetermined length.

Furthermore, the wall surface surrounded by the outer surface of the air needle core sleeve has a taper on one side close to the air outlet end, so that the air needle core sleeve seals the port of the mounting part on one side of the air outlet end to prevent molten plastic from overflowing from a gap between the mounting part and the air needle core sleeve.

Further, the cross-sectional area of the gas channel at the gas inlet end is larger than the cross-sectional area of the gas channel at the gas outlet end, so as to control the flow speed and flow rate of the gas when the gas leaves the gas channel and enters the flow channel.

Further, the first predetermined length is 1.5mm to 2 mm.

The nitrogen nozzle assembly used in the gas-assisted mold can avoid the occurrence of gas leakage phenomenon of the nitrogen nozzle in the working process to the maximum extent due to the tight combination between the nitrogen nozzle and the insert, and the tight structural design and the specific position relation among the nitrogen nozzle, the fixed mold insert and the sealing ring. After the nitrogen nozzle is installed on the fixed die insert, the sealing ring of the nitrogen nozzle is arranged between the gas needle core sleeve and the fixed die in a compressed mode to fill the gap between the gas needle core sleeve and the fixed die, and therefore sealing requirements of parts are met.

Further, the nitrogen nozzle of the invention is firstly arranged on the insert of the fixed die, and then the assembly is fixed on the fixed die, thereby ensuring that the sealing ring is not damaged in the installation process. Moreover, the nitrogen nozzle can be conveniently detached, installed and maintained on the gas-assisted mold in the mounting mode.

The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments thereof, taken in conjunction with the accompanying drawings.

Drawings

Some specific embodiments of the invention will be described in detail hereinafter, by way of illustration and not limitation, with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the drawings:

FIG. 1 is a schematic illustration of an assembly of a nitrogen nozzle assembly for use in gas assisted forming, according to an embodiment of the present invention;

FIG. 2 is an enlarged fragmentary view of the nitrogen nozzle assembly of FIG. 1 assembled;

FIG. 3 is a detailed view of the air core sleeve of FIG. 1 showing the air core sleeve in elevation, cross-sectional, and top views;

FIG. 4 is a detailed view of the air needle core of FIG. 1 showing the air needle core in front, cross-sectional, top, and bottom views;

fig. 5 is a perspective view of the air needle core, the air needle core cover, and the seal ring shown in fig. 1, taken apart.

The symbols in the figure represent the following meanings:

1. the gas needle comprises a moving die, a runner, a nitrogen nozzle, a gas needle core, a nitrogen nozzle 31, a gas needle core, a nitrogen nozzle 32, a gas needle core sleeve 33, a sealing ring, a fixed die insert 4, a fixed die insert 5, a screw, a gas channel 6, a fixed die 7, a fixed die 81, a first end 82, a second end 83, a sealing groove 91, a gas inlet end 92 and a gas outlet end.

Detailed Description

Referring to fig. 1 and 5, the nitrogen nozzle 3 of the present invention is mainly composed of a gas needle core 31, a gas needle core cover 32, and a seal ring 33. Figure 3 shows the internal and external configuration of the air core sleeve 32 in detail. Figure 4 shows the internal and external structure of the air needle core 31 in detail. The structure of the nitrogen gas nozzle will be described in detail below with reference to fig. 3, 4, and 5.

As shown in fig. 3, the air needle core sleeve 32 has a long cylindrical shape, and a wall surface surrounded by an outer surface of the air needle core sleeve 32 has a shape formed by combining a plurality of cylinders having different diameters. At the first end 81 of the air needle core sleeve 32, the wall bounded by its outer surface is a first cylinder having a first diameter and having a first length extending along the central axis. At the second end 82 of the air needle core sleeve 32, the wall bounded by its outer surface is a second cylindrical shape having a second diameter and having a second length extending along the central axis. The first cylinder shape and the second cylinder shape are combined, the central axes of the first cylinder shape and the second cylinder shape are the same, the first diameter is larger than the second diameter, and the first length is smaller than the second length. The wall defined by the outer surface of the air needle core sleeve 32 is tapered at the second end 82. And the air needle hub 32 is provided at the first end 81 with a seal groove 83 provided circumferentially around the inner wall surface of the first cylindrical first end 81. Therefore, the wall surface surrounded by the outer surface of the air core sleeve 32 is finally approximately in a T shape. The air needle core sleeve 32 defines a receiving space therein.

As shown in fig. 4, the air needle core 31 is fixed in the accommodation space. In order to fix the air needle core 31 in the accommodating space better, a wall surface surrounded by the outer surface of the air needle core 31 is matched with the inner wall surface of the air needle core sleeve 32 to be fixed tightly. The air needle core 31 also has two ends, an air inlet end 91 and an air outlet end 92. Inlet end 91 corresponds to first end 81 and outlet end 92 corresponds to second end 82. Between the inlet end 91 and the outlet end 92 is a through channel of the air needle core 31, i.e. an air channel, so that air can smoothly flow from the inlet end 91 to the outlet end 92 in the air channel. The cross-sectional area of the gas channel at the gas inlet end 91 is greater than the cross-sectional area of the gas channel at the gas outlet end 92. This is advantageous for controlling the flow rate and flow of gas as it leaves the gas channel. In this embodiment, the cross-sectional area of the gas channel at gas outlet end 92 decreases sharply. Since the flow rate of the gas is related to the change of the cross section of the passage through which the gas flows, the gas can obtain a faster flow rate after passing through the gas passage having a sharply reduced cross section.

As shown in fig. 5, the gas passage composed of the gas inlet end 91 and the gas outlet end 92 is provided at the side of the wall surface surrounded by the outer surface of the gas needle core 31. And the sealing ring 33 is arranged at one side of the air inlet end 91, and the sealing ring 33 is arranged in the sealing groove 83 of the air needle core sleeve 32.

As shown in fig. 1 and 2, the nitrogen gas nozzle 3 including the gas cylinder 31, the gas cylinder cover 32, and the packing 33 is installed in the fixed mold insert 4. The fixed mold insert 4 has a mounting portion capable of nesting the air needle core sleeve 32. The wall surface enclosed by the outer surface of the air needle core sleeve 32 is matched with the inner wall surface of the mounting part. In particular, the wall defined by the outer surface of the air needle core sleeve 32 has a taper on the side of the second end 82, i.e., the side close to the air outlet end 92, which enables the air needle core sleeve 32 to seal the mounting portion on the side of the air outlet end 92, so as to prevent molten plastic from overflowing from the gap between the mounting portion and the air needle core sleeve 32 during operation. In one embodiment, the taper of the air core sleeve 32 at the second end 82 matches the taper of the fixed mold insert 4 at the same side, and in order to prevent the matching gap between the tapers of the air core sleeve 32 and the fixed mold insert 4 from being too large, the matching gap between the tapers of the air core sleeve 32 and the fixed mold insert 4 is generally set to be 0.01-0.02 mm. Alternatively, the fit clearance of the taper of the air needle core sleeve 32 and the fixed mold insert 4 may be 0.015 mm. Optionally, the fit clearance of the conicity of the air needle core sleeve 32 and the fixed mold insert 4 can also be 0.01 mm. Optionally, the fit clearance of the taper of the air needle core sleeve 32 and the fixed mold insert 4 can also be 0.02 mm.

In another embodiment, the nitrogen gas nozzle 3 composed of the air core 31, the air core sleeve 32 and the sealing ring 33 may be installed in a movable mold insert. The movable mold insert is fixed in the movable mold 1. And correspondingly, the fixed die 7 is provided with the runner 2, and the movable die 1 is provided with the air passage 6 for introducing air from the outside. The air needle core 31, the air needle core sleeve 32 and the movable mold insert are hermetically attached to the movable mold 1 at one side of the air inlet end 91 so as to prevent gas from leaking when entering the gas channel from the gas passage 6.

Further, the air-assisted die is provided with a fixed die 7 and a movable die 1 which can be separated. The fixed die 7 and the movable die 1 are respectively an upper part and a lower part of the die and can be parted at a set position. The fixed die 7 is provided with a gas passage 6 for introducing gas from the outside. The fixed mold insert 4 is fixed in the fixed mold 7, and the air needle core 31, the air needle core sleeve 32 and the fixed mold insert 4 are hermetically attached to the fixed mold 7 on one side of the air inlet end 91 so as to avoid leakage of air when the air enters the air channel from the air passage 6. In this embodiment, the fixed mold insert 4 is fixed to the fixed mold 7 by a plurality of screws or bolts 5. After the nitrogen nozzle 3 is fixed to the fixed mold insert 4, the sealing ring 33 of the nitrogen nozzle 3 is disposed between the gas needle core sleeve 32 and the fixed mold 7, so that the sealing ring 33 can seal a gap between the gas needle core sleeve 32 and the fixed mold 7, and prevent gas from overflowing from the gap when entering the gas channel from the gas channel 6.

Further, the movable mold 1 is provided with a flow channel 2, and the flow channel 2 is a flow channel after gas enters a cavity in the gas-assisted mold. The fixed die insert 4 is attached to the moving die 1 at one side of the air outlet end 92. The gas needle core 31 exceeds the surface of the fixed mold insert 4 on the side of the gas outlet end 92 by a first preset length on the side of the gas outlet end 92. In this embodiment, the first predetermined length is 1.5mm to 2 mm. The designer of the application further discovers that when the first preset length exceeds 2mm, the length of the gas needle core 31 can break through the flow channel 2 of the cavity of the gas-assisted mold, so that gas cannot completely enter the flow channel 2, but instead, the gas can leak in the flow channel 2, and further the molding of a product is influenced; on the contrary, when the first predetermined length is less than 1.5mm, the too small length of the gas needle core 31 may cause insufficient power for the introduced gas to initially enter the flow channel 2, thereby affecting the product molding by the gas in the flow channel 2. The designer of the present application thus finds, but with a first predetermined length in the range of 1.5mm to 2mm, that the gas can completely enter the flow channel 2 with a suitable initial momentum and then shape the product well in the flow channel 2. That is, the first predetermined length may be 1.5mm, 1.6mm, 1.8mm, 2mm, etc. And the air pin sleeve 32 exceeds the fixed mold insert 4 on the side of the air outlet end 92 by a second predetermined length. The first predetermined length is greater than the second predetermined length, that is, the length of the air needle core 31 extending into the flow channel 2 is greater than the length of the air needle core sleeve 32 extending into the flow channel 2. Therefore, the gas can smoothly enter the flow channel 2 through the air core 31, rather than flowing back into the air core cover 32.

The nitrogen nozzle assembly is arranged in the fixed die insert 4, and particularly comprises a nitrogen nozzle 3. The air needle core 31 in the nitrogen nozzle 3 is provided with an air passage for communicating the air passage 6 with the runner 2, so that after external air enters the air needle core 31 through the air passage 6 of the fixed die 7, the external air enters the runner 2 of the movable die 1 through the air passage of the air needle core 31 to push molten plastic in the runner 2 to a preset position, and a hollow casting plastic product is obtained.

Further, the installation step of the nitrogen nozzle 3 is explained in detail with reference to fig. 1 to 5. First, the gas cylinder 31, the gas cylinder cover 32, and the packing 33 are assembled into the nitrogen nozzle 3. Then, the nitrogen gas nozzle 3 is installed in the fixed mold insert 4. Subsequently, the fixed mold insert 4 is fastened to the fixed mold 7 with screws 5. The gap between the nitrogen gas nozzle 3 and the gas duct 6 of the stationary mold 7 is sealed with a seal ring 33. This manner of securing avoids high rates of failure of the seal ring 33 during installation. The nitrogen nozzle 3 is installed with its inlet end 91 abutting against the gas duct 6 and its outlet end 92 extending a first predetermined length into the flow channel 2. Because the nitrogen nozzle 3 is coated in the gas-assisted mould due to the molten plastic in the gas inlet process, gas cannot leak on the runner 2, and the instability of the product in production is caused.

Further, the air core sleeve 32 and the air core 31 have special processing precision requirements. In order to achieve a better fit between the air needle core sleeve 32 and the air needle core 31 during use, the dimensional accuracy of the two planes of the air needle core 31 is required to be controlled in an important way, and particularly, the dimensional requirement of a position with tolerance is required to be within a tolerance range.

Thus, it should be appreciated by those skilled in the art that while a number of exemplary embodiments of the invention have been illustrated and described in detail herein, many other variations or modifications consistent with the principles of the invention may be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be understood and interpreted to cover all such other variations or modifications.

Claims

1. A nitrogen gas nozzle assembly for use in a gas-assisted mold, the gas-assisted mold having therein an insert for housing the nitrogen gas nozzle assembly, the nitrogen gas nozzle assembly disposed in the insert and comprising:

the gas needle core sleeve is embedded in the mounting part of the insert, the wall surface surrounded by the outer surface of the gas needle core sleeve is matched with the inner wall surface of the mounting part, and a containing space is limited in the gas needle core sleeve; and

the gas needle core is fixed in the accommodating space, the wall surface surrounded by the outer surface of the gas needle core is matched with the inner wall surface of the gas needle core sleeve to be tightly fixed, the gas needle core is provided with a gas channel communicated with a gas channel and a flow channel, the gas channel is used for introducing gas from the outside, and the flow channel is a flow channel after the gas enters a cavity in the gas-assisted mold; and is

The gas channel is provided with a gas inlet end connected with the gas channel and a gas outlet end connected with the flow channel, and the gas needle core exceeds the surface of the insert on one side of the gas outlet end by a first preset length;

the gas needle core is sleeved on one side of the gas outlet end and exceeds the surface of the insert on one side of the gas outlet end by a second preset length, wherein the first preset length is larger than the second preset length.

2. The nitrogen nozzle assembly as claimed in claim 1, wherein the gas-assisted mold has a fixed mold and a movable mold which are separable, the fixed mold is provided with the gas passage, the movable mold is provided with the flow passage, wherein the insert is a fixed mold insert fixed in the fixed mold, and the gas needle core, the gas needle core sleeve and the fixed mold insert are in sealing fit with the fixed mold on the side of the gas inlet end so as to prevent gas from leaking from the gas passage into the gas passage.

3. The nitrogen nozzle assembly as claimed in claim 1, wherein the gas-assisted mold has a fixed mold and a movable mold which are separable, the fixed mold is provided with the flow passage, the movable mold is provided with the gas passage, wherein the insert is a movable mold insert fixed in the movable mold, and the gas needle core, the gas needle core sleeve and the movable mold insert are hermetically attached to the movable mold on the side of the gas inlet end to prevent gas from leaking from the gas passage into the gas passage.

4. The nitrogen nozzle assembly as recited in claim 2, further comprising:

the sealing ring is arranged on one side of the air inlet end and arranged between the air needle core sleeve and the fixed die, so that the sealing ring can seal a gap between the air needle core sleeve and the fixed die to prevent gas from entering the gas channel from overflowing from the gap.

5. The nitrogen nozzle assembly as claimed in claim 4, wherein said gas needle hub has a seal groove around a circumference of said gas channel on a side of said gas inlet end, said seal ring being disposed in said seal groove.

6. The nitrogen nozzle assembly of any one of claims 1-5, wherein a wall bounded by an outer surface of the air spike sheath is tapered on a side adjacent the air exit end such that the air spike sheath seals a port of the mounting portion on the air exit end side to prevent molten plastic from escaping from a gap between the mounting portion and the air spike sheath.

7. The nitrogen nozzle assembly of any of claims 1-5, wherein the cross-sectional area of the gas channel at the gas inlet end is larger than the cross-sectional area thereof at the gas outlet end to control the flow rate and flow of gas as it exits the gas channel into the flow passage.

8. The nitrogen nozzle assembly as recited in claim 1, wherein the first predetermined length is between 1.5mm and 2 mm.