Needle valve hot runner system

Abstract

The present invention discloses a needle valve type hot runner system, which includes a valve needle, a manifold plate, a hot nozzle assembly, and a driving mechanism for driving the valve needle to extend and retract. The manifold plate is provided at one end of the hot nozzle assembly, and the other end of the hot nozzle assembly is the discharging end. The manifold plate and the hot nozzle assembly have a communicating valve needle hole, and the valve needle is inserted into the valve needle hole. An active block is provided in the housing of the driving mechanism. The outer side wall of the active block has a circle of convex ridges, and the convex ridges divide the cavity into a first cavity and a second cavity. One end of the active block is detachably connected with a limiting block. This system can effectively improve the stability of the valve needle, and the distribution channel is also arranged at the end of the valve needle, which can reduce the temperature loss caused by premature fluid diversion and the problem of poor flow. And the stability of pneumatic drive can be ensured through the structure of the convex ridges; the limiting block is modularly designed, and different sizes of limiting blocks can be replaced during use.

Description

Technical Field

[0001] The present invention belongs to the technical field of molds, and particularly relates to a hot runner system. Background Art

[0002] The hot runner system is generally applied to injection molds. By heating, the plastic in the runner and the gate is kept in a molten state. The hot runner system generally consists of several parts such as a hot nozzle, a manifold plate, a temperature control box, and accessories. The hot nozzle generally includes two types: an open hot nozzle and a needle valve hot nozzle. Since the form of the hot nozzle directly determines the selection of the hot runner system and the manufacture of the mold, the hot runner system is often correspondingly divided into an open hot runner system and a needle valve hot runner system;

[0003] The needle valve hot runner system drives the movement of the valve needle through a pneumatic component to control the flow rate of the plastic fluid; in the prior art, the runner in the system is branched in the manifold plate and then enters the valve needle hole. Since the valve needle is generally relatively long, in order to obtain a better fluid flow effect, the processing requirements for parts such as the valve needle and the valve needle hole are very high, and the relatively long valve needle will inevitably shake during use, affecting the outflow of the fluid.

[0004] In addition, the valve needle of the needle valve hot runner system is driven by compressed air. In the prior art, the driving mechanism for driving the valve needle is designed with reference to a cylinder, and the pressure holding of its driving force is not very stable; in addition, since different molds have different requirements for the telescopic stroke of the valve needle, that is, each hot runner system has different requirements for the movement stroke of the driving mechanism, the driving mechanism cannot achieve a modular design with a unified structure. Summary of the Invention

[0005] The main technical problem to be solved by the present invention is to provide a needle valve hot runner system, which can effectively improve the stability of the valve needle, reduce the processing precision requirements of the entire valve needle mechanism, and the runner is also arranged at the end of the valve needle, which can reduce the temperature loss caused by premature fluid diversion and the problem of poor flow. And through the structure of the convex rib, the stability of the pneumatic drive can be ensured, and the pressure holding after the movement of the moving block can be ensured to be stable; by making the limit block into a modular design, different sizes of limit blocks can be replaced during use.

[0006] To solve the above technical problem, one technical solution adopted by the present invention is as follows:

[0007] A needle valve hot runner system, comprising a valve needle, a manifold plate, a hot nozzle assembly, and a driving mechanism for driving the valve needle to expand and contract, wherein the driving mechanism is driven by compressed air;

[0008] The flow splitter is arranged at one end of the hot nozzle assembly, and the other end of the hot nozzle assembly is the discharging end. The flow splitter and the hot nozzle assembly have a communicating valve needle hole, and the valve needle is inserted into the valve needle hole, and the valve needle can reciprocate along its axial direction;

[0009] The flow splitter and the hot nozzle assembly have a communicating main flow channel. A valve needle sleeve is arranged at the discharging end of the hot nozzle assembly. The valve needle sleeve has a flow splitting channel communicating with the main flow channel and a positioning hole communicating with the valve needle hole. The flow splitting channel communicates with the positioning hole. The valve needle is inserted into the positioning hole, and the valve needle and the positioning hole are in clearance fit;

[0010] The driving mechanism includes a housing. The housing has a cylindrical cavity. An active block is arranged in the cavity. The active block can move along the axial direction of the cavity. The valve needle is fixedly connected to the active block;

[0011] The outer side wall of the active block has a circle of convex ribs, and the side wall of the convex ribs has a groove for installing a sealing ring. The convex ribs divide the cavity into a first cavity and a second cavity. Air holes are arranged in both the first cavity and the second cavity. The active block is pushed to move by injecting compressed air into the first cavity or the second cavity;

[0012] A limiting block is detachably connected to one end of the active block. The valve needle is fixedly connected to the other end of the active block and passes out of the housing.

[0013] Further, the active block includes a telescopic block and a fixed block. The convex ribs are located on the side wall of the telescopic block. The telescopic block has a groove. The fixed block can be placed into the groove and fixedly connected to the telescopic block. The fixed block has a through hole arranged along the axial direction of the housing. The through hole is a stepped hole with two apertures. The valve needle can pass through the through hole and is limited by the stepped hole.

[0014] Further, the fixed block and the telescopic block are in clearance fit, and a sealing ring is arranged between them. The fixed block and the telescopic block are fixed by a snap ring.

[0015] Further, one end of the fixed block extends out of the groove and out of the housing, and the fixed block and the housing are sealed by a sealing ring.

[0016] Further, one end of the active block has a convex column, and the limiting block is threadedly connected to the convex column.

[0017] Further, the housing includes a columnar housing and two end caps respectively fixedly connected to both ends of the columnar housing. One of the end caps has a through opening for the valve needle to pass through.

[0018] Furthermore, the positioning hole is a stepped hole with two different diameters. The part with the smaller diameter has a clearance fit with the valve needle, and the part with the larger diameter communicates with the shunt channel.

[0019] Furthermore, the discharging end of the hot nozzle assembly has a mounting hole, and the valve needle sleeve is fixedly installed in the mounting hole.

[0020] Furthermore, there is a clearance between the outer side wall of the valve needle sleeve and the inner side wall of the mounting hole. One end of the valve needle sleeve inserted into the mounting hole has a flange. A locking member is also included. The locking member is inserted into the clearance and fixedly connected to the hot nozzle assembly, and the locking member can abut against the flange to fix the valve needle sleeve.

[0021] Furthermore, the valve needle sleeve is a copper-made valve needle sleeve, and there are 3 valve needles. The 3 valve needles are circumferentially and evenly distributed around the axis of the hot nozzle.

[0022] Advantages of the present invention:

[0023] In the present invention, the positioning part of the valve needle is arranged at the end of the valve needle, which can effectively improve the stability of the valve needle, reduce the processing precision requirements of the entire valve needle mechanism, and the shunt channel is also arranged at the end of the valve needle, which can reduce the temperature loss caused by premature fluid shunting and the problem of poor fluid flow.

[0024] The positioning hole is a stepped hole with two different diameters for positioning and guiding respectively. Simply put, the positioning hole combines the functions of positioning the valve needle and the flow channel. Only the end of the valve needle contacts the fluid to control the fluid. Most of the fluid flows in the same flow channel in the hot nozzle, and the fluidity is very good.

[0025] The driving mechanism divides the cavity into two non-communicating parts through the convex rib, and drives the movable block by injecting compressed air into the two cavities respectively, thereby driving the telescopic movement of the valve needle fixedly connected to the movable block. Moreover, the structure of the convex rib can ensure the stability of the air pressure drive and ensure the pressure holding stability after the movement of the movable block;

[0026] The movable block is detachably connected with a limit block. The movement stroke of the movable block is limited by the distance between the limit block and the housing. The driving mechanism can be designed into a modular form, and different-sized limit blocks can be replaced during use.

[0027] The movable block includes a telescopic block and a fixed block. The fixed block has a through hole axially arranged along the housing. The through hole is a stepped hole with two aperture sizes. The valve pin can pass through the through hole and be limited by the stepped hole. The valve pin is installed through the stepped hole and is pressed and fixed by a combined assembly method. The structure is simple, and the installed valve pin can have very good stability and service life. Moreover, the replacement of the valve pin is relatively convenient.

[0028] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly and implement it according to the content of the specification, the following takes the preferred embodiments of the present invention and combines with the drawings to describe in detail as follows. Brief Description of the Drawings

[0029] Figure 1 is a schematic structural diagram of the valve pin type hot runner system of the present invention;

[0030] Figure 2 is a cross-sectional view of the valve pin and the hot nozzle assembly of the present invention;

[0031] Figure 3 is a cross-sectional view of the valve pin sleeve of the present invention;

[0032] Figure 4 is an exploded structural diagram of the valve pin and the hot nozzle assembly of the present invention;

[0033] Figure 5 is an exploded structural diagram of the drive mechanism of the present invention;

[0034] Figure 6 is a cross-sectional view of the drive structure of the present invention;

[0035] Figure 7 is an exploded structural diagram of the movable block of the present invention;

[0036] The reference signs of each part in the drawings are as follows:

[0037] valve pin 1, manifold plate 2, hot nozzle assembly 3, valve pin hole 31, main runner 32, mounting hole 33, valve pin sleeve 4, sub-runner 41, positioning hole 42, flange 43, locking member 5, drive mechanism 6, housing 61, movable block 62, convex rib 621, annular groove 626, first cavity 611, second cavity 612, limiting block 622, columnar housing 613, end cover 614, telescopic block 623, fixed block 624, groove 6231, through hole 6241, convex column 625 and snap ring 63. Detailed Description of the Embodiments

[0038] The following combines the drawings to elaborate on the preferred embodiments of the present invention in detail, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0039] Embodiment:

[0040] A valve needle type hot runner system, as Figures 1 to 4 shown: The hot runner system includes a valve needle 1, a manifold 2 and a hot nozzle assembly 3;

[0041] The manifold is provided at one end of the hot nozzle assembly, the other end of the hot nozzle assembly is the discharging end, the manifold and the hot nozzle assembly have a communicating valve needle hole 31, the valve needle is inserted into the valve needle hole, and the valve needle can reciprocate along its axial direction;

[0042] The manifold and the hot nozzle assembly have a communicating main runner 32, a valve needle sleeve 4 is provided at the discharging end of the hot nozzle assembly, the valve needle sleeve has a diverging channel 41 communicating with the main runner, and a positioning hole 42 communicating with the valve needle hole, the diverging channel communicates with the positioning hole, the valve needle is inserted into the positioning hole, and the valve needle and the positioning hole are in clearance fit.

[0043] In the hot runner system of the present invention, the positioning part of the valve needle is arranged at the end of the valve needle, which can effectively improve the stability of the valve needle, reduce the processing precision requirements of the whole valve needle mechanism, and the diverging channel is also arranged at the end of the valve needle, which can reduce the temperature loss caused by premature diversion of the fluid and the problem of poor fluid flow.

[0044] In this embodiment, there are 3 valve needles, and the 3 valve needles are circumferentially and evenly distributed around the axis of the hot nozzle. The arrangement of the 3 valve needles is beneficial to the uniform entry of the fluid into the mold, and there will be no high internal pressure, which can prevent the problems of air holes and wire drawing in the injection-molded products.

[0045] This embodiment, as Figure 2 and 3 shown: The positioning hole is a stepped hole with two different diameters, wherein the part with the smaller diameter is in clearance fit with the valve needle, and the part with the larger diameter communicates with the diverging channel.

[0046] Simply put, the positioning hole serves both to position the valve needle and as a runner. Only the end of the valve needle contacts the fluid to control the fluid, and the fluid mostly flows in the same runner in the hot nozzle, with very good fluidity.

[0047] As Figure 2 and 4 shown: The discharging end of the hot nozzle assembly has a mounting hole 33, and the valve needle sleeve is fixedly installed in the mounting hole.

[0048] There is a gap between the outer side wall of the valve needle sleeve and the inner side wall of the mounting hole. One end of the valve needle sleeve inserted into the mounting hole has a flange 43. It further includes a locking member 5. The locking member is inserted into the gap and fixedly connected to the hot nozzle assembly, and the locking member can abut against the flange to fix the valve needle sleeve. In this embodiment, the locking member is threadedly connected to the hot nozzle assembly.

[0049] In this embodiment, the valve needle sleeve is fixed by the locking member, which is convenient for the modular design of the product. For hot runner systems of different specifications, only the valve needle and the valve needle sleeve need to be replaced, and the valve needle sleeve does not need to be processed with a structure connected to the hot nozzle, which is convenient for manufacturing.

[0050] In this embodiment, the valve needle sleeve is a copper valve needle sleeve. The copper material has fast heat conduction and good heat storage, which can ensure the temperature of the fluid and thus ensure its fluidity.

[0051] This embodiment further includes a driving mechanism 6. The driving mechanism is connected to the valve needle to drive the reciprocating movement of the valve needle. The driving mechanism uses compressed air as the driving power.

[0052] The driving mechanism is as Figure 5 and Figure 6 shown: It includes a housing 61. The housing has a cylindrical cavity. An active block 62 is provided in the cavity. The active block can move along the axial direction of the cavity. The valve needle 1 is fixedly connected to the active block;

[0053] The outer side wall of the active block has a circle of convex ridges 621, and the side wall of the convex ridges has a groove 626 for installing a sealing ring. The convex ridges divide the cavity into a first cavity 611 and a second cavity 612. The first cavity and the second cavity are both provided with air holes. By injecting compressed air into the first cavity or the second cavity, the active block is pushed to move;

[0054] One end of the active block is detachably connected with a limit block 622. The valve needle is fixedly connected to the other end of the active block and passes out of the housing.

[0055] The valve needle driving mechanism of the present invention divides the cavity into two non - communicating parts by the convex ridges, and drives the active block by injecting compressed air into the two cavities respectively, thereby driving the telescopic movement of the valve needle fixedly connected to the active block; the active block is detachably connected with a limit block, and the movement stroke of the active block is limited by the distance between the limit block and the housing, that is, when the active block moves, the movement space of the active block is limited by limit blocks of different heights, so as to realize the control of the stroke.

[0056] In this embodiment, the housing is as Figure 6As shown in the figure, it includes a columnar shell 613 and two end caps 614 fixedly connected to both ends of the columnar shell respectively. One of the end caps has a through hole 6141 for the valve needle to pass through.

[0057] That is to say, the shell of this embodiment is a split structure. The split setting has the advantages of being easy to process and convenient for later maintenance. In this embodiment, the columnar shell and the two end caps are in interference connection, and the shell in interference connection can meet the requirements of both stable connection and sealing at the same time.

[0058] The movable block is as Figure 7 As shown in the figure, it includes a telescopic block 623 and a fixed block 624. The convex rib is located on the side wall of the telescopic block. The telescopic block has a groove 6231. The fixed block can be placed into the groove and fixedly connected to the telescopic block. The fixed block has a through hole 6241 arranged along the axial direction of the shell. The through hole is a stepped hole with two hole diameters. The valve needle can pass through the through hole and be limited by the stepped hole.

[0059] The valve needle is installed through the stepped hole, and the valve needle is pressed and fixed by a combined assembly method. The structure is simple, and the installed valve needle can have very good stability and service life, and the replacement of the valve needle is also relatively convenient. In this embodiment,

[0060] The fixed block and the telescopic block are in clearance fit, and a sealing ring is provided between them. The fixed block and the telescopic block are fixed by a circlip 63. It can be understood that because the fixed block and the telescopic block are in clearance fit, the assembly is very convenient. Then, it is fixed by a circlip. The circlip is a standard part, and its disassembly and assembly are very convenient.

[0061] One end of the fixed block extends out of the groove and passes through the shell, and the fixed block and the shell are sealed by a sealing ring.

[0062] In this embodiment, one end of the movable block has a convex column 625, and the limiting block is threadedly connected to the convex column. The threadedly connected limiting block is very convenient for installation and replacement. Moreover, the threaded connection structure has better stability and is not easy to loosen compared with the movable block in linear motion.

[0063] The working principle of the present invention is as follows:

[0064] The hot runner system sets the positioning part of the valve needle at the end of the valve needle, which can effectively improve the stability of the valve needle, reduce the processing accuracy requirements of the entire valve needle mechanism, and the runner is also set at the end of the valve needle, which can reduce the temperature loss caused by premature fluid diversion and the problem of poor flow.

[0065] The positioning hole is a stepped hole with two different diameters for positioning and guiding the flow respectively. Simply put, the positioning hole combines the functions of positioning the valve needle and the flow channel. Only the end of the valve needle contacts the fluid to control the fluid. Most of the fluid flows in the same flow channel within the hot nozzle, and the fluidity is very good.

[0066] The valve needle sleeve is fixed by a locking member, which is convenient for the modular design of the product. For hot runner systems of different specifications, only the valve needle and the valve needle sleeve need to be replaced. The valve needle sleeve does not need to be processed with a structure connected to the hot nozzle, and the manufacturing is convenient.

[0067] The valve needle driving mechanism divides the cavity into two non - communicating parts through a rib, and drives the movable block by injecting compressed air into the two cavities respectively, thereby driving the expansion and contraction of the valve needle fixedly connected to the movable block. Moreover, the structure of the rib can ensure the stability of the pneumatic drive and the pressure - maintaining stability after the movement of the movable block; the movable block is detachably connected with a limit block, and the movement stroke of the movable block is restricted by the distance between the limit block and the housing, that is, when the movable block moves, its movement space is restricted by limit blocks of different heights, so as to realize the control of the stroke.

[0068] The movable block includes a telescopic block and a fixed block. The fixed block has a through - hole arranged along the axial direction of the housing. The through - hole is a stepped hole with two hole diameters. The valve needle can pass through the through - hole and is limited by the stepped hole. The valve needle is installed through the stepped hole and is pressed and fixed by a combined assembly method. The structure is simple, and the installed valve needle can have very good stability and service life, and the replacement of the valve needle is also relatively convenient.

[0069] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. All equivalent structural transformations made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are equally included in the patent protection scope of the present invention.

Claims

1. A needle valve type hot runner system, characterized in that: It includes a valve needle (1), a manifold plate (2), a hot nozzle assembly (3), and a driving mechanism (6) for driving the valve needle to extend and retract. The driving mechanism is driven by compressed air; The manifold plate is provided at one end of the hot nozzle assembly. The other end of the hot nozzle assembly is the discharging end. The manifold plate and the hot nozzle assembly have a communicating valve needle hole (31). The valve needle is inserted into the valve needle hole, and the valve needle can reciprocate along its axial direction; The manifold plate and the hot nozzle assembly have a communicating main flow channel (32). A valve needle sleeve (4) is provided at the discharging end of the hot nozzle assembly. The valve needle sleeve has a diverging flow channel (41) communicating with the main flow channel, and a positioning hole (42) communicating with the valve needle hole. The diverging flow channel communicates with the positioning hole. The valve needle is inserted into the positioning hole, and the valve needle and the positioning hole are in clearance fit; The driving mechanism includes a housing (61). The housing has a cylindrical cavity. An active block (62) is provided in the cavity. The active block can move along the axial direction of the cavity. The valve needle is fixedly connected to the active block; The outer side wall of the active block has a circumferential rib (621), and the side wall of the rib has a groove for installing a sealing ring. The rib divides the cavity into a first cavity (611) and a second cavity (612). Both the first cavity and the second cavity are provided with air holes. By injecting compressed air into the first cavity or the second cavity, the active block is pushed to move; One end of the active block is detachably connected with a limit block (622). The valve needle is fixedly connected to the other end of the active block and passes out of the housing; The active block includes a telescopic block (623) and a fixed block (624). The rib is located on the side wall of the telescopic block. The telescopic block has a groove (6231). The fixed block can be placed into the groove and fixedly connected with the telescopic block. The fixed block has a through hole (6241) arranged along the axial direction of the housing. The through hole is a stepped hole with two different diameters. The valve needle can pass through the through hole and be limited by the stepped hole.

2. The needle valve type hot runner system according to claim 1, characterized in that: The fixed block and the telescopic block are in clearance fit, and a sealing ring is provided between them. The fixed block and the telescopic block are fixed by a snap ring (63).

3. The needle valve type hot runner system according to claim 1, characterized in that: One end of the fixed block extends out of the groove and out of the housing, and the fixed block and the housing are sealed by a sealing ring.

4. The needle valve type hot runner system according to claim 1, wherein: One end of the active block has a convex column (625). The limit block is threadedly connected to the convex column.

5. The needle valve type hot runner system according to claim 1, characterized in that: The housing includes a columnar housing (613) and two end caps (614) respectively fixedly connected to both ends of the columnar housing. One of the end caps has a through opening for the valve needle to pass through.

6. The needle valve type hot runner system according to claim 1, wherein: The positioning hole is a stepped hole with two different diameters. The part with the smaller diameter is in clearance fit with the valve needle, and the part with the larger diameter communicates with the diverging flow channel.

7. The needle valve type hot runner system according to claim 6, characterized in that: The discharging end of the hot nozzle assembly has a mounting hole (33). The valve needle sleeve is fixedly installed in the mounting hole.

8. The needle valve type hot runner system according to claim 7, wherein: A gap is provided between the outer sidewall of the valve needle sleeve and the inner sidewall of the mounting hole. One end of the valve needle sleeve inserted into the mounting hole has a flange (43). A locking member (5) is further included. The locking member is inserted into the gap and fixedly connected to the hot nozzle assembly, and the locking member can abut against the flange to fix the valve needle sleeve.

9. The needle valve type hot runner system according to claim 1, characterized in that: The valve needle sleeve is a copper valve needle sleeve. There are 3 valve needles, and the 3 valve needles are circumferentially evenly distributed around the axis of the hot nozzle.

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