JP3052752U - Check valve for injection molding machine - Google Patents

Abstract

(57) [Problem] In a check valve having a tapered contact surface between a ring valve and a wear plate, a breakage accident occurs in the tapered portion of the ring valve due to internal resin pressure or wedge force. SOLUTION: The shape of a wear plate is applied to a ring valve at a right angle with respect to an axis, and corresponds to a resin passage extending from a mating surface of a wear plate with a shaft portion between screw head resin passages to an outer periphery. The large radius processing of the part enables stable molding without trouble.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to the shape of a check valve of an injection molding machine.

[0002]

[Prior art]

 Conventionally, in the construction of a check valve for a molten resin backflow in injection molding, in the case of a raw material resin which does not like the retention of the molten resin, for example, in the case of vinyl chloride molding, a ring valve and a wear valve are disclosed as disclosed in JP-A-10-034715. The contact surface of the plate was tapered and had a slope so that the flow of the molten resin became smooth.

[0003]

[Problems to be solved by the invention]

 However, in the above-described configuration, a stress accident of the resin internal pressure or a wedge force occurs in the tapered portion of the ring valve, thereby causing a breakage accident. The present invention solves the above problems and provides an improved check valve.

[0004]

[Means for Solving the Problems]

 In order to solve the above problems, in the present invention, a wear plate was provided via a thin shaft portion at the rear of the head body of the screw inserted into the heating cylinder, and a ring valve was loosely fitted to the shaft portion between the resin passages of the screw head. In this case, the wear plate is abutted by a seal portion at a plane perpendicular to the ring valve and the shaft to prevent a breakage accident. In addition, a portion corresponding to the resin passage extending from the mating surface of the wear plate to the shaft portion between the screw head resin passages and the outer periphery thereof is formed into a round shape, so that the flow of the molten resin is smoothened. It became a check valve for injection molding machines.

[0005]

[Embodiment of the invention]

 FIG. 1 is a partial sectional view of a screw or the like incorporating a check valve including a wear plate according to the present invention. Reference numeral 1 denotes a heating cylinder, in which the screw 2 and the ring valve 4 are rotatably and reciprocally fitted and inserted to plasticize and injection-fill the raw material resin. The wear plate 3 usually has a flat or tapered resin passage surface. However, the wear plate 3 has a stepped structure and is fitted and inserted through the thin shaft portion 10 of the screw head. The ring valve 4 is loosely fitted and screwed into the screw 2 by engaging the alignment with the shaft portion between the resin passages.

As shown in FIG. 1, the molten resin conveyed from the rotating screw at the time of plasticization passes through the opened seal part 7 when the ring valve 4 moves forward due to the molten resin pressure. 4 through a resin passage 8 which is a gap between the inner diameter of the screw head 5 and the outer peripheral portion of the shaft of the screw head 5 and a groove 9 which has been subjected to a smooth processing to allow the molten resin to pass through at the time of plasticization with which the ring valve 4 comes into contact. The fluid flows into the conical portion at the tip of the screw head 5.

The wear plate 3 is provided with a seal portion 7 which comes into contact with the ring valve 4 at a plane perpendicular to the shaft in order to prevent the ring valve from being damaged, and the wear plate 3 is mated with the shaft portion between the screw head resin passages. A check valve is provided to ensure a smooth resin passage so that a portion corresponding to the resin passage extending from the outer periphery to the outer periphery is formed as large as possible in the R portion 6.

As an example, screw diameter: 160 mm Wear plate R portion: 9 mm R / screw diameter = 9/160 = 0.056 The numerical value of R is R = screw diameter × 0.05-0 according to the screw diameter. .13 is preferred.

[0009]

[Effect of the invention]

 In the wear plate shape of the check ring according to the present invention, by making the contact surface with the ring valve perpendicular to the axis, it is possible to prevent the ring valve from being damaged and to prevent the wear plate from being screwed down. By making the portion corresponding to the resin passage extending from the mating surface with the shaft portion to the outer periphery large R processing, troubles such as stagnation and burning of the resin can be eliminated.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a screw and a heating cylinder incorporating a check ring according to the present invention.

[Explanation of symbols]

 1 ‥‥‥ Heating cylinder 2 ス ク Screw 3 ‥‥‥ Wear plate 4 リ ン グ Ring valve 5 ‥‥‥ Screw head 6 ‥‥‥ R part 7 シ ー ル Seal part 8 樹脂 Resin passage 9 ‥‥溝 Groove 10 細 Fine shaft

Claims (1)

[Utility model registration claims] A wear plate is provided at a rear portion of a head body of a screw inserted into a heating cylinder of an injection device through a thin shaft portion, and a ring valve is loosely fitted to a shaft portion between resin passages of the screw head. The wear plate is contacted by a seal portion at a surface perpendicular to the ring valve and the shaft, and a portion corresponding to a resin passage extending from the mating surface of the wear plate to the shaft portion between the screw head resin passages toward the outer periphery is subjected to R processing. A check valve for an injection molding machine.