JP3197858U - Injection molding equipment - Google Patents

Abstract

An injection molding apparatus capable of reliably reducing resin leakage from a through hole of a valve stem to a rear end side where an air cylinder or the like is located when injection molding is performed by a hot runner method and a gate is opened and closed by a valve stem. provide. A nozzle housing 2 having a gate g opened at a front end and a flow path 4 communicating with the gate g and penetrating along the axial direction is disposed on the rear end side of the housing 2, A manifold 6 having a flow path 7 for supplying melted resin with the tip side communicating with the path 4, a gate g is opened and closed at the front end 11, and the center of the flow path 4 and the resin supply path 7 are arranged along the axial direction. A valve stem 10 that can be moved forward and backward, and a piston 24 that is positioned on the rear end side of the manifold 6 and is fixed to the rear end portion 12 of the valve stem 10 is advanced and retracted along the front end side and the rear end side together with the valve stem 10. A packing 22 is attached, which includes the air cylinder 17 to be enabled, and contacts the peripheral surface of the cylinder chamber 18 at a position where the valve stem 10 penetrates. [Selection] Figure 1

Description

  The present invention is an injection molding device with excellent maintainability that can reliably reduce resin leakage from the through hole of the valve stem that opens and closes the gate when injection molding resin material melted by the hot runner method. About.

  In a hot runner type injection molding apparatus, a melted resin material is pumped from a resin supply path in a manifold to a resin flow path in a nozzle housing, and the resin material is filled into a cavity from a gate on the tip side. It has been adopted. The gate is formed by a valve stem that advances and retreats along the axial direction in the center of the nozzle housing and in the manifold, and the advancement / retraction operation of the valve stem moves the piston attached to the rear end of the piston chamber to the cylinder chamber (See, for example, Patent Document 1).

  For example, like the injection molding apparatus 30 shown in FIG. 3, the nozzle housing 2 with the gate g at the tip facing the cavity C, the manifold 6 adjacent to the rear end side (upward in FIG. 3), and adjacent to the rear end side. An air cylinder 17 and a valve stem 10 that advances and retracts along the axial direction in the center of the resin flow path 4 in the nozzle housing 2 and in the manifold 6 are provided. The melted resin supplied from the resin flow path 7 in the manifold 6 is filled into the cavity C from the gate g through the resin flow path 4 in the nozzle housing 2. When closing the gate g, in order to advance the valve stem 10 including the front end portion 11 toward the cavity C, high-pressure air is supplied into the cylinder chamber 19 on the rear end side, and high pressure in the cylinder chamber 18 on the front end side is supplied. By discharging the air to the outside, the piston 24 is advanced together with the valve stem 10 to the tip side.

As shown in FIG. 3, the valve stem 10 includes a through hole 6h provided in the manifold 6 and a through hole 14h provided in the valve bushing 14 constituting the tip side of the cylinder chamber 18 on the tip side (downward in FIG. 3). And slidably penetrates. Therefore, if a part of the melted resin that is pumped through the resin supply path 7 to the gate g side leaks into the cylinder chamber 18 through the through holes 6h and 14h, for example, the movement of the piston 24 is hindered. May cause problems such as In order to prevent such a problem, an escape hole (drain hole) for allowing the resin to escape from the through hole 14h of the valve bushing 14 into the hollow portion 13 between the manifold 6 and the manifold plate 9 located on the outer peripheral side thereof. 29 is formed.
However, in the case where the escape hole 29 is provided, the resin that has leaked through the hole 29 accumulates in the hollow portion 13, so that the resin that has been decomposed and deposited almost periodically is removed. There is a problem that complicated and long-time maintenance is required and the maintenance cost is high.

Japanese Patent No. 5128147 (pages 1 to 11 and FIGS. 1 to 4)

  The present invention solves the problems described in the background art. When injection molding is performed by the hot runner method and the gate is opened and closed by the valve stem, the valve stem passes from the through hole to the rear end where the air cylinder is located. It is an object of the present invention to provide an injection molding apparatus that can reliably reduce the state of resin leakage.

In order to solve the above-mentioned problem, the present invention arranges a packing closely contacting the peripheral surface of the valve stem in a cylinder chamber of a fluid pressure cylinder such as an air cylinder in which the valve stem advances and retreats along the axial direction. Invented.
That is, an injection molding apparatus according to the present invention (Claim 1) includes a nozzle housing having a gate opening at the tip and a resin flow path communicating with the gate and penetrating along the axial direction, and the nozzle housing. A manifold that has a resin supply path that is disposed on the rear end side and that supplies a melted resin that communicates with the resin flow path at the front end side, and that opens and closes the gate at the front end portion. A valve stem having a central portion that can be moved back and forth along the axial direction of the front end side and the rear end side, and a piston that is positioned on the rear end side of the manifold and fixed to the rear end portion of the valve stem. A fluid pressure cylinder capable of moving forward and backward along the front end side and the rear end side together with the stem, and the valve stem at a position through which the valve stem penetrates in the front end side cylinder chamber of the fluid pressure cylinder. Comprising mounting a packing in contact with the peripheral surface systems out, characterized in that.

  Further, according to the present invention, the packing is supported by a holder having a convex ring that accommodates the packing inside in a concave formed in a bottom surface inside a valve bushing constituting a part of the cylinder chamber on the tip side. Also included is an injection molding apparatus (claim 2).

According to the injection molding apparatus of the first aspect, a part of the melted resin that is pumped to the gate side through the resin supply path formed in the manifold is transferred from the through hole of the valve stem into the cylinder chamber of the fluid pressure cylinder. It is possible to prevent or reduce the situation of leakage or leakage from the escape hole into the hollow portion. Therefore, stable injection molding can be performed, the above-described maintenance period is lengthened, and the maintenance cost can be reduced.
Further, according to the injection molding apparatus of the second aspect, the packing can be easily arranged together with the holder from the through hole of the valve stem to the front end side cylinder chamber of the fluid pressure cylinder.

The fluid pressure cylinder includes, for example, an air cylinder and a hydraulic cylinder having a cylinder and a piston that are operated by a pressure fluid.
The packing is made of, for example, a heat-resistant synthetic rubber (for example, fluororubber) or a synthetic resin, and has a circular O-ring with a circular cross section, a square ring with a square cross section, or an overall ring shape and Examples include, but are not limited to, a sealing material having one or more tongue-shaped contact pieces in an annular shape along the inner peripheral surface.
Furthermore, the holder that supports the packing may be either a form in which only the convex ring is inserted into the concave part of the valve bushing or a form in which the entire holder including the convex ring can be inserted into the concave part. .

Sectional drawing which shows the outline of the injection molding apparatus of this invention. (A) is the elements on larger scale which show the vicinity of the packing and holder in FIG. 1, (B) is the elements on larger scale similar to (A) which shows the holder of a different form. Sectional drawing which shows the outline of the conventional injection molding apparatus.

Below, the form for implementing this invention is demonstrated. In the following description, the lower side in FIG. 1 is referred to as the front end side, and the upper side is referred to as the rear end side.
As shown in FIG. 1, an injection molding apparatus 1 according to the present invention includes a cylindrical nozzle housing 2 having a gate g at the tip, a manifold 6 adjacent to the rear end, and an air cylinder (fluid pressure cylinder adjacent to the rear end). 17) and a pin (round bar) shaped valve stem 10 for opening and closing the gate g.
The nozzle housing 2 includes a conical portion 3 having a gate g at the tip, and a resin flow path 4 communicating with the gate g extends along the inner side in the axial direction. A band heater 5 is wound around the nozzle housing 2. The housing 2 includes a nozzle tip, a tip insulator, etc. (not shown).

The manifold 6 incorporates a resin supply path 7 having a substantially L shape for supplying molten resin supplied from a sprue nozzle (not shown) to the resin flow path 4. In the resin supply path 7, the tip end side that is coaxial along the axial direction of the resin flow path 4 communicates with the resin flow path 4.
Further, the valve stem 10 is disposed so as to be able to advance and retreat (slide) along the front / rear (axial) direction along the center of the bent portion of the resin supply path 7 and the center of the resin flow path 4, and the tip 11 thereof. Opens and closes the gate g. The rear end portion 12 of the valve stem 10 is fixed to a piston 24 that moves in the air cylinder 17.

As shown in FIG. 1, the air cylinder 17 is surrounded by the piston 24, the valve bushing 14 on the front end side (part), and the manifold back plate 27 on the rear end side, and is slidably disposed inside these. The cylinder chamber 18 on the front end side and the cylinder chamber 19 on the rear end side partitioned by the piston 24 are configured. An air intake pipe and an exhaust pipe (not shown) communicate with the cylinder chambers 18 and 19 individually.
The manifold back plate 27 is provided with a lid 28 for sealing the cylinder chamber 19 from the outside.
The valve bushing 14 has a substantially cylindrical shape as a whole, and is connected to the rear end surface of the manifold 6 through a concave-convex fitting. A cylindrical concave portion 16 is opened on the bottom surface 15 inside the valve bushing 14. Is formed.

Further, as shown in FIG. 2 (A), a plate-like holder 20 is fixed to the bottom surface 15 inside the valve bushing 14 by bolts b, and the tip of the holder 20 has a convex surface. A ring 21 is projected. The convex ring 21 accommodates (supports) an O-ring (packing) 22 containing a hollow portion on the inner side 23 thereof. The O-ring 22 and the convex ring 21 are inserted into the concave portion 16 opened in the bottom surface 15, and the inner peripheral surface of the O-ring 22 advances and retreats through the through hole 14 h of the valve bushing 14. It is in close contact with the peripheral surface of the stem 10 while being elastically deformed.
In order to replace the O-ring 22, when the bolt b is removed and the holder 20 is taken out, the O-ring 22 is taken out together with the holder 20.
As shown in FIG. 1, a cavity insert 8 having a conical recess 8a is disposed around the front end side of the nozzle housing 2, and the rear end side of the nozzle housing 2, the manifold 6, and the A manifold plate 9 is disposed around the valve bushing 14 through a hollow portion 13.

In the injection molding apparatus 1 as described above, the melted resin pressure-fed from the resin supply path 7 of the manifold 6 to the resin flow path 4 of the nozzle housing 2 is a gap between the tip 11 of the valve stem 10 and the gate g. To the cavity C and molded into a predetermined resin product.
During the molding operation, a part of the melted resin is passed through the resin supply passage 7 of the manifold 6 while the valve stem 10 is advanced and retracted, and the through hole 6 h of the manifold 6 and the through hole 14 h of the valve bushing 14. And flow into.

  However, according to the injection molding apparatus 1, the inner peripheral surface of the O-ring 22 housed in the inner side 23 of the convex ring 21 in the holder 20 is always on the inner bottom surface 15 in the valve bushing 14. Close to the surrounding surface. As a result, it is possible to reliably prevent a part of the melted resin from leaking into the cylinder chamber 18 on the front end side. Therefore, stable injection molding can be performed, the long-time maintenance described above is unnecessary, and the maintenance cost can be reduced.

FIG. 2B is an enlarged view similar to FIG. 2A showing the holder 25 having a different form. As shown in FIG. 2B, the holder 25 has an O-ring 22 accommodated in a ring groove 26 having a relatively small diameter formed on the bottom surface 15 inside the valve bushing 14, and the opening of the ring groove 26. The bolt b fixes the flat plate holder 25 arrange | positioned at the bottom face 15 of the said valve bushing 14 containing a part.
The O-ring 22 is always in close contact with the peripheral surface of the valve stem 10 whose inner peripheral surface advances and retreats while elastically deforming into an elliptical shape having a long axis in the illustrated vertical direction as a whole.
The valve bushing 14 having the ring groove 26 and the holder 25 can achieve the same effects as when the holder 20 is used.

The present invention is not limited to the form described above.
For example, the holders 20 and 25 are made of metal and made of heat-resistant synthetic resin, and an arbitrary shape can be selected as the visual shape in the front-rear direction.
The holder 20 may have a ring groove on the inner peripheral surface of the convex ring 21.
Further, the packing used in the present invention is a solid structure O-ring, a quad ring having a substantially cross-shaped or star-shaped cross section, a square ring having a hollow section and a square section, or the □ ring. However, it is good also as a form which provided the reinforcing material which consists of a thin metal plate in the middle of the inside and outside direction.
In addition, the packing has a ring shape as a whole and a U-shaped cross-section, and is open to the inner peripheral side, and an annular metal spring in the opening, or the circumferential direction of the opening. It is good also as a compound ring which has inserted the annular metal spring which has many slits along.

  According to the present invention, stable injection molding can be performed by the hot runner method, and when the gate is opened and closed by the valve stem, resin leakage from the through hole of the valve stem to the rear end side where the air cylinder or the like is located is ensured. An injection molding apparatus that can be reduced can be provided.

1 ……………… Injection molding device 2 …………… Nozzle housing 4 …………… Resin channel 6 …………… Manifold 7 …………… Resin supply channel 10 ………… Valve stem 11 ………… Valve stem tip 12 ………… Valve stem rear end 14 ………… Valve bushing 15 ………… Bottom side of valve bushing 16 ………… Recess 17 ………… Air cylinder (Fluid pressure cylinder)
18 ………… Cylinder chamber 20, 25… Holder 21 ………… Convex ring 22 ………… O-ring (packing)
g ......... Gate

Claims (2)

A nozzle housing (2) having a gate (g) opened at the tip and a resin flow path (4) communicating with the gate (g) and penetrating along the axial direction;
A manifold (6) having a resin supply passage (7) disposed on the rear end side of the nozzle housing (2) and supplying molten resin with the tip end side communicating with the resin flow passage (4);
The gate (g) can be opened and closed at the front end (11), and the center of the resin flow path (4) and the resin supply path (7) can be moved back and forth along the axial direction between the front end and the rear end. A valve stem (10) to be disposed;
The piston (24) positioned on the rear end side of the manifold (6) and fixed to the rear end portion (12) of the valve stem (10) is advanced and retracted along the front end side and the rear end side together with the valve stem (10). Fluid pressure cylinder (17) enabling
A packing (22) that contacts the peripheral surface of the valve stem (10) is attached to a position where the valve stem (10) penetrates in a cylinder chamber (18) on the tip side of the fluid pressure cylinder (17).
An injection molding apparatus (1) characterized by the above. The packing (22) is placed in a recess (16) formed in the bottom surface (15) inside the valve bushing (14) constituting a part of the cylinder chamber (18) on the tip side. It is supported by a holder (20) having a convex ring (21) accommodated inside,
The injection molding apparatus (1a) according to claim 1, characterized in that

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