JPS5865639A - Multi-valve nozzle of injection molder - Google Patents

Abstract

PURPOSE:To make the retention of molten resin hardly occur, by locating the outer circumferential surface of a resin inflow hole in a plane that does not pass the axis of a needle valve, and flowing a molten resin from the inflow hole into a valve chamber helically. CONSTITUTION:The molten resin fed from a heating cylinder is introduced via a connecting bore 14. When the resin flows from the inflow hole 15 into the valve chambers 16a, 16b, since the outer circumferential surface of the inflow hole 15 lies in a plane that does not pass the axis of the needle valves 18a, 18b, the molten resin flows from the inflow hole 15 via one side of each of the chambers 16a, 16b into the valve chambers 16a, 16b so that the flow becomes helical and therefore the retention of the resin would hardly occur. The injection is performed through nozzle holes 17a, 17b.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a needle valve type multi-pulp nozzle for an injection molding machine.

This type of conventional device will be explained with reference to FIGS. 1 to 4. Reference numeral 1 denotes a heating cylinder, and a screw 2 is rotatably and axially slidably inserted into the inner diameter surface of the heating cylinder.

3 is a multi-pulp nozzle scattered at the tip of the heating cylinder 1, which introduces the molten resin from the heating cylinder 1 through the connection hole 4, passes through the inlet hole 5, and enters the valve chambers 6a and 6.
b and is injected from nozzle holes 7a and 7b. The nozzle holes 7a and 7b are provided with needle valves 8a and 8b, respectively, and are normally closed by springs 9m and 9b that press from behind the needle valves 8a and 8b. When the pressure exceeds the pressing force of the springs 9m and 9b, the springs are opened and injection is performed.

However, since the inflow hole 5 and the needle valves 8a and 8b are arranged in the same plane, retentions A and B occur as shown in FIGS. 3 and 4. These retentions A and B can be alleviated to some extent by the shape of the needle valve arm and the inlet hole 5, but they cannot be completely eliminated.16 Also, the needle valves that open and close each nozzle hole 7a and 7b must operate at the same time. However, due to the current situation as described above, the pressures of each resin in the valve chamber do not reach the same value at the same time. Therefore, the opening and closing operations of the needle valves were not performed simultaneously, which was inconvenient.

The object of the present invention is to eliminate the above-mentioned drawbacks and provide a needle valve type multi-pulp nozzle in which the nozzle can be opened and closed at the same time.

Next, referring to FIG. 5 and FIG. 6, one embodiment of the present invention will be explained by taking the case of two nozzle holes as an example. 11 is a heating cylinder, and a screw 12 is rotatable and slidable in the axial direction. is inserted into its inner diameter surface.

Numeral 13 is a multi-pulp nozzle which is guided into the heating cylinder 1] valve chambers 16a and 16b, and is guided through nozzle holes 17 & and 1
The injection is performed from 7b. Needle valves 18m and 18b are provided in the valve chambers 16a and 16b, respectively, and are normally pushed by hydraulic pressure acting in the direction of arrow A on hydraulic plungers 19a and 19b behind the needle valves 18a and 18b. Although the nozzle holes 17a and 17b are respectively blocked, when the resin pressure in the valve chambers 16a and 16b becomes larger than the pressing force due to the hydraulic pressure acting on the plungers 19'a and 19b, the needle valves close against the pressing force. 18a and 18b move back by a predetermined amount (move to the right in the figure), open nozzle holes 17m and 17b, and perform injection. 20m and 20b are bushes provided coaxially with the needle valves 18a and 18b;
It supports the needle valves 18a and 18b.

The pressing force acting on the back of the needle valve 18a and the lug 8b is not determined by a hydraulic pressure such as oil pressure as described above (but may also be a pneumatic pressure such as air, or as explained in the conventional example). It is obvious that a spring may be used for this purpose.

Further, the inflow j115 is R from the outer surface to the connection hole 14.
The stoppers 21 m and 21 b having a section are discharged. As shown in FIG. 6, the inlet hole 15 is configured such that the outer circumferential surface of the inlet droplet 15 is in contact with the outer circumferential surface of the needle valves 18m and 18b. Further, as shown in FIG. 7, the outer peripheral surface of the inflow hole 15 is a plane different from the axis C of the needle valves 18a and 18b. Therefore, as shown in FIGS. 8 and 9, the molten resin flows around from the inflow hole 15 to the valve chambers 16a and 16b from only one side, forming a spiral flow and causing stagnation.

In addition, the portion of the tip of the stopper 2 and 21b that is in contact with the hole diameter surface of the valve chambers 16a and 16b is rounded along the same hole diameter surface, and a bushing that supports the needle valve 18 is added as shown in FIG. If the resin is made to protrude into the valve chamber 16 and the corner portion relative to the inflow hole 15 is made a smooth slope with respect to the resin flow to prevent stagnation, the coke will be smooth and stagnation will be less likely to occur, and a spiral shape will be formed. The flow will also be more effective.

Furthermore, as mentioned above, there is no accumulation of resin flowing into the valve chamber, so there is no difference in the resin pressure depending on each nozzle, and there is no variation in the opening/closing operation of the needle valve. By providing a pressing mechanism, opening and closing operations can be performed even more simultaneously.

[Brief explanation of drawings]

FIG. 1 is a diagram of a conventional device. Figure 2 is cross section 1 in Figure 1.
Figure -1. 3 and 4 are diagrams explaining the flow state of resin in the nozzle, and FIG. 3 is a detailed view of FIG. 2. The fourth drawing is a detailed view of the 101st part in Fig. 1. FIG. 5 is a diagram showing an embodiment according to the present invention. Figure 6 is cross section I of Figure 5.
−■Figure. The seventh diagram shows another embodiment of the present invention, in which the outer periphery of the inflow east passes through the axis of the needle valve. FIGS. 8 and 9 are explanatory diagrams according to the implementation of the present invention, and FIG. 8 shows an inflow. This is a detailed view of the connection between the valve chamber and the valve chamber, and is a detailed view of Figure 6. Figure 9 is a detailed view of part 2j of Figure 5. 14... Connection hole, 15... Inflow hole, 16a, 35b
...Valve room. 17m, 17b-Nozzle hole% 15m, 18b-
Needle valve b2o'a. 20b...Bush. =19 ku 314 ya 4 figure

Claims (1)

[Claims] 1. When the resin melted and measured in the heating cylinder of an injection molding machine is allowed to flow into a mold having two or more gates, the heating cylinder and the mold opening are communicated. In a multi-pulp nozzle in which opening and closing of two or more gates and the same number of nozzle holes are controlled by needle valves, one nozzle is provided coaxially with the heating cylinder on an extension of the outlet of the molten resin at the tip of the heating cylinder. The connecting hole and the valve chambers having the same axis as the needle valve and the same number as the two or more gates having a nozzle hole at the tip, and the connecting hole and the valve chamber radially communicating with each other, and , the molten resin has a ten-sided axis different from the needle valve's fine detail, and the molten resin flows around the outer periphery of the needle valve only from one side, flowing in a spiral shape, and the outer periphery touches the outer periphery of the needle valve. an inflow hole that communicates in a range from a position to a position that coincides with the axis of the needle valve, and two or more nozzle holes for closing a nozzle hole provided at an end opposite to the nozzle hole in the needle valve, respectively. A multi-pulp nozzle for an injection molding machine consisting of an independently installed suppression mechanism. 2. A multi-pulp nozzle for an injection molding machine according to claim 1, wherein the suppression mechanism is a hydraulic cylinder or a pneumatic cylinder. 4. In the pulp according to Claims 1 to 3, an end face facing the valve chamber of a bush supporting the needle valve protrudes into the valve chamber at a communication portion between the inflow hole and the resin flow path. A multi-valve nozzle for an injection molding machine that has a smooth sloped surface for the flow of resin from the inflow hole.