JPH0337693Y2 - - Google Patents

Description

[Detailed description of the invention] ≪Industrial application field≫ This invention relates to a filter element in which each folded piece of a filtration member folded in a zigzag shape is expanded into a fan shape. This invention relates to an improvement in molding and sealing an opening at an outer peripheral end.

≪Prior Art≫ In this type of filter element, a disk-shaped filtration member that has been expanded in advance into a fan shape is loaded into a mold in order to simplify the work of attaching the frame to the inner and outer peripheries and the sealing work. The frame portion and the sealing resin coating portion are integrally molded by injection molding.

FIG. 4 shows a conventional filter element obtained by this molding technique, in which an inner frame part 2 is integrated on the inner circumferential side of each folding piece 1, and an outer frame part 3 on the flange is integrated on the outer circumferential side. are integrated. The folding piece has triangular openings on the upper and lower surfaces of the outer frame portion 3, and each opening is closed by a resin coating portion (indicated by diagonal lines) 4a, 4b.

≪Problems to be solved by the invention≫ The problem with this structure is the flow of the resin during injection molding of the resin constituting the frame portions 2, 3 and the resin coating portions 4a, 4b. The issue to be resolved is where to set it.

In other words, in the past, the only structure available was to set the gates on the upper and lower surfaces of the frames 2 and 3 and allow the flow to flow toward the openings. This is because, as is clear from a glance at the drawing, the mold can only be formed into a shape that sandwiches the top and bottom of each folded piece 1, and the position of the gate perpendicular to the parting plane between the molds is located at the frame portion 2. This is because only cavities constituting 3 were obtained.

Therefore, the position of the gate is limited to the upper and lower surfaces of the frame parts 2 and 3, and therefore the tail of the gate protrudes above the frame parts 2 and 3 when die-cutting.

There is no problem if this kind of tail protrudes from the inner frame 2, but if the tail protrudes from the outer frame 3, the protrusion of the tail may cause problems when the frame 3 is sandwiched between the flanges of the case. This may impair the sealing properties,
Deburring work becomes extremely troublesome due to poor attachment.

This idea solves the above drawbacks, and allows the resin to flow well into the triangular opening on the outside without setting a gate on the top surface of the outer frame, forming a resin film with sealing properties. It is intended to.

<<Means for solving the problem>> In order to achieve the above-mentioned object, this invention expands each folded piece of a zigzag-folded filter member into a fan shape with one end as the inner periphery and the other end as the outer periphery. In a filter element in which a frame part is integrally molded on the inner and outer peripheral parts, and a resin coating part for sealing is integrally molded on the inner end surface of the triangular opening of the filter member located above and below the outer frame part, the triangular shape The present invention is characterized in that an outer circumferential wall portion communicating with the sealing resin coating portion is formed at a plurality of locations outside the opening, and a gate portion for taking in the resin is formed on the top surface of the outer circumferential wall portion.

<<Operation>> The resin flowing from the gate flows from the outer circumferential wall toward the frame and the triangular opening, completely blocking the outer circumference. Therefore, the surface of the frame is finished in a smooth state.

<<Example>> Hereinafter, an example of this invention will be described in detail using the drawings.

1 and 2 show a filter element according to this invention.

In the figure, reference numeral 10 denotes a filter element, and this filter element 10 is made by folding a filter member in a zigzag shape, unfolding it into a fan shape with the cut end of each folded piece 12 as the inner periphery, and the cut end of the other end as the outer periphery. It has a disk shape with a conical head, and frame portions 14 and 16 are integrally molded on the inner and outer peripheral portions by injection molding.

The inner frame part 14 has a cylindrical shape, and each folding piece 1
It is integrally molded to completely cover the inner opening of 2.

Further, the outer frame portion 16 has a flange shape.
An outer triangular opening formed by each of the folded pieces 12 is formed on the upper and lower sides of the frame 16, and this portion has a resin coating portion 18 shown with diagonal lines.
completely sealed by. In addition, frame part 1
A plurality of outer circumferential wall portions 20 are formed at appropriate intervals above and below sandwiching the folding piece 12 between two triangular portions on the outer circumferential side of the folding piece 12. Each outer peripheral wall portion 20 communicates between the frame portion 16 and the resin coating portion 18.

A gate portion 2 is provided on the top surface of each outer peripheral wall portion 20.
2 is formed, and the gate of the molding die is separated from this portion during die cutting.

Note that a specific outer circumferential wall portion 2 of each outer circumferential wall portion 20
A protruding piece 22a is formed at the top of the gate 22 so that the lower part of the gate part 22 is convex. This protrusion 22a
are formed at three locations at 120° intervals and function to position the filter element 10 when it is assembled into a filter case (not shown).

Next, a mold structure for molding the filter element 10 having the above structure will be explained using FIG. 3.

The figure shows upper and lower molds 24, 24 for molding the filter element 10, and a mold surface that follows the shape of each folded piece 12 is formed between the two molds 24, and the parting surface thereof is a first cavity 26 for forming the frame portion 14 inside;
A second cavity 28 for forming the frame portion 16 and the resin coating portion 18 on the outer side, and a third cavity 30 communicating with the second cavity 26.
is formed. The third cavity 30 forms the outer peripheral wall portion 20. A gate 32 and a runner 34 communicating with the end of the third cavity 30 are formed in each mold 24 so as to be perpendicular to the parting surface. A gate 36 and a runner 38 also communicate with the end of the first cavity 24 .

Therefore, during resin injection molding, the resin enters the third cavity 30 through the gate 32 in the outer part, and then flows around into the second cavity 28 through the third cavity 30, and one side is on the frame 16 side. Meanwhile, the other fluid flows toward the side where the resin coating 18 is formed.

It goes without saying that the number and arrangement interval of the outer peripheral wall portions 20 are determined by taking resin flow into consideration.

<<Effects>> As explained in detail using the examples above, in the filter element of this invention, the resin can flow well into the triangular opening on the outside without setting a gate on the upper surface of the outer frame. However, a resin film with sealing properties can be formed. Therefore, failure to seal the outer frame portion due to the tail of the gate and failure to attach it to the case will not occur, and the complexity of deburring work can also be eliminated.

[Brief explanation of the drawing]

Fig. 1 is a half-cut side view showing a filter element according to this invention, Fig. 2 is a plan view showing a quarter of the filter element, Fig. 3 is a half sectional view showing a molding die, and Fig. 4 is a half-cut side view showing a filter element according to the invention. FIG. 3 is a half-cut side view showing a conventional filter element. 10...Filter element, 12...Folding piece, 14...Inner frame portion, 16...Outer frame portion, 18
...resin coating part, 20...outer peripheral wall part, 22... gate part.

Claims (1)

[Claims for Utility Model Registration] (1) Each folded piece of a filtration member folded in a zigzag shape is expanded into a fan shape with one end as the inner periphery and the other end as the outer periphery, and a frame is integrally formed on the inner and outer peripheries. At the same time, in the filter element in which a sealing resin coating part is integrally molded on the inner end surface of the triangular opening of the filter member located above and below the outer frame part, the sealing resin coating part is formed at multiple locations outside the triangular opening. 1. A filter element comprising: an outer peripheral wall communicating with the resin coating; and a gate for taking in the resin formed on the top surface of the outer peripheral wall. (2) The filter element according to claim 1, wherein the gate portion also serves as a positioning protrusion for positioning the filter element within the case.