JPS6155408B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a strainer body having a mesh on its peripheral surface.

When feeding fuel from a vehicle's fuel tank to the engine via a suction pipe, it is very common to attach a filter or strainer to the end of the pipe to prevent dust from entering the tank from getting into the pipe. In addition to the examples mentioned here, if we also look at the requirements in other fields, the demand for this technology has become extremely large. Therefore, from the consumer side,
There was a demand for the unit price of the strainer itself to be as low as possible, and in order to meet this demand, the main body was made of plastic, which had a relatively small number of parts and required less material, was economical, and could easily be made into any shape by injection molding. A strainer has been developed for use in this section. now,
An example of this is shown in FIG. 1 and briefly described. The strainer main body 1 has a substantially cylindrical shape, and has a plurality of crosspieces 2 extending in the axial direction at appropriate intervals in the circumferential direction.
(In this case, four at 90° intervals) connect the upper and lower annular frames 3 and 4, and connect the upper and lower annular frames 2 and 2 adjacent to the
A mesh body 5 that controls a filter function is provided in each space in the circumferential direction between the filters.

In such a cylindrical main body 1, a blind bottom plate 6 is attached to the lower frame 4, and a top plate 8 through which a suction pipe 7 passes is attached to the upper frame 3, but generally, as shown in the figure, the bottom plate 6 is The top plate 8 is integrally molded with the main body structure 1 described above, and the top plate 8 is separately molded and then attached to the upper frame 3 by snapping, gluing, ultrasonic welding, or the like. However, of course, the bottom plate 6 may also be molded separately.

In such a strainer, what is time-consuming and has the greatest impact on cost is the technique of incorporating the mesh body 5, which exhibits a filter function, into the main body 1, apart from attaching the top plate and the bottom plate. In general, a method for relatively rationally performing this integration is to embed the net body integrally when injection molding the above-mentioned main body 1. Although this method is simpler than other methods, there are still points to be improved. In order to clarify this point, we will add an explanation to this conventional integral embedding method in accordance with Figure 2, which shows an injection molding machine consisting of a normal fixed mold and a movable mold. The main parts of the movable mold are shown.

That is, assuming that the runner, gate, etc. from the injection source are located in a fixed mold (not shown), the movable mold 9 that reciprocates in the axial direction A on one molding process surface has a core pin 10, This core pin creates a space that defines the inside of the cylindrical body, and a groove 11 that defines a crosspiece in the axial direction is cut on the circumferential surface.

The mold portions facing the outer surface of the molded product with respect to the core pin 10 are slide molds 12a and 12b that open and close in the direction B perpendicular to the axis.

Therefore, the net body 5 is made by rolling a net formed into a sheet shape into a cylindrical shape and joining both edges.
After this is fitted onto the outer periphery of the core pin 10, the slide molds 12a and 12b are closed together, and then the whole is advanced toward the fixed mold and a normal molding process using this type of mold configuration is performed. When the molding of the cylindrical main body 1 is completed (in some cases, the bottom plate 6 is also molded at the same time), the corresponding portion of the net is embedded and fixed in the crosspiece 2. Thereafter, the molded product is taken out from between the slide molds which are reciprocated and opened again using a known ejector or by hand.

However, the above method has the following drawbacks.

First, it is difficult to form many molded products by arranging a large number of core pins in parallel. This is because fitting the net 5 onto the core pin 10 is a manual process, and it must be done carefully by aligning the seams of the net with the slits in the core. On the other hand, it takes time to complete the mesh fitting work, and there is a risk of resin burning on the material being used. The fact that it is impossible to produce a large number of pieces naturally leads to higher costs.

Also, if the molding process is repeated continuously,
This leads to overheating of the core pin 10, and even if the mesh is insert molded, it will no longer be a good product.

The present invention aims to provide a molding method that overcomes the above-mentioned defects while following the known method of molding a strainer body using a core pin and a slide mold.

Embodiments of the method of the present invention will be described below with reference to FIG. 3 and subsequent figures. Parts corresponding to known parts are given the same reference numerals as in FIGS. 1 and 2, but the features of the present invention are as follows:
One physical feature is that the core pin 10 is detachably attached to the fixed surface part 13 of the movable mold that supports the core pin 10.

That is, an extension leg part 14 is provided below the core pin 10 as a mounting part, and an insertion hole 15 through which the leg part 14 penetrates is bored at a predetermined position of the fixing surface part 13 on which the core pin is installed. Particularly in this case, in order to facilitate this insertion, the circumferential surface of the leg portion 14 is tapered, and the corresponding inner circumferential surface of the insertion hole is also tapered in a complementary manner.

Therefore, according to the manufacturing method of the present invention, the following steps are performed.

First, the rolled net body 5 is fitted in advance onto the core pin 10 which has been removed from the fixed surface portion 13 of the movable mold 9 so that the seam thereof is located in the slit 11 of the pin.

In this way, the core pin 10 prepared in advance
and the assembly of the net body 5 when both sliding mold parts 12a and 12b of the movable mold 9 are open,
The core pin leg part 14 is casually inserted into the insertion hole 15 of the fixing surface part 13 and assembled into the mold 9.

This core pin insertion operation does not require caution and can be easily performed, so even if a large number of core pins are inserted, it does not take much time. is possible.

After this, as shown in the fourth diagram, both slide parts 1
2a, 12b are closed while the entire movable mold 9 is moved into engagement with the schematically shown stationary mold 16;
Conventional injection molding is carried out. In addition, Chamba 17
The upper frame 3 is integrally molded in the chamber 18, and the lower frame 4 and the bottom plate 6 are integrally molded.The runner R, the sapmathon gate G, etc. are also schematically shown on the fixed mold.

In particular, if you prepare in advance more core pins 10 than are required for one molding, you can use the time during molding effectively to use the remaining core pins 10 (not shown). ) for the next molding, and the overall working time can be reasonably shortened.

That is, as shown in FIG.
Once a and 12b are open, pull out the molded product (strainer body 1) along with the core pin 10 (you can also use an ejector), and immediately insert another core pin prepared in advance into which a net has been fitted. 10 can be inserted, and in this way, it is possible to immediately move on to the next molding. Then, during this next molding, in parallel with the preassembly work of the net to the core pin, the previous molded product, which has been extracted together with the core pin, may be removed from the core pin.

Therefore, even if a large number of pieces are taken out using more core pins than before, the core pins can be quickly attached and detached without having to worry about it, and the time during molding can be used effectively, resulting in less problems such as resin burning. Without a doubt,
The waiting time for molding machines and resin will be significantly shortened, improving time utilization and operation rates, which will greatly contribute to lower costs.

Moreover, since the core pin is replaced with a cold one each time during each molding, it is possible to prevent the molded product from becoming defective due to abnormal heating of the core pin.

In the illustrated embodiment, each core pin is provided with a mounting portion 14 and is inserted and removed individually. However, this mounting portion 14 is made into a plate shape and several core pins are erected thereon, while the fixing surface portion 13 Instead of the single insertion hole 15, a recess into which this plate-shaped mounting portion is fitted may be provided, so that a plurality of core pins can be attached and detached at once.

As described above, according to the present invention, an extremely rational method for manufacturing a strainer body can be provided. It goes without saying that the shape of the main body and the net body may be cylindrical with a rectangular cross section or other shapes, and the integral molding of the bottom plate 6 is arbitrary. In addition, in the case shown, the top plate has a ridge 19 that creates a groove in the upper frame for future snap attachment.
(Fig. 4) is also provided on the core pin 10,
This is also an optional issue.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an example of a strainer to which the present invention is applied, FIG. 2 is a schematic perspective view of a movable mold produced by a conventional manufacturing method, and FIG. 3 is a schematic perspective view of a movable mold produced by the present invention manufacturing method. FIG. 4 is a schematic cross-sectional view of the inside of the mold during molding, and FIG. 5 is a schematic cross-sectional view of the inside of the mold after molding. In the figure, 1 is the strainer body, 2 is the crosspiece, 3 is the upper frame, 4 is the lower frame, 5 is the mesh body, 9 is the movable mold, 10 is the core pin, 12a, 12b are the sliding mold parts,
13 is a core pin fixing surface part, 14 is a core pin leg part,
15 is an insertion hole.

Claims (1)

[Claims] 1. After providing a core pin in a movable mold and fitting a net around the outer periphery of the core pin, the core pin and the outer periphery of the net are closed by closing a pair of slide mold parts together, and the movable mold is fixed. A strainer in which annular upper and lower frames are connected by a plurality of circumferentially spaced crosspieces extending in the axial direction by plastic injection molding in combination with a mold, and the net is arranged in the circumferential space between adjacent crosspieces. A manufacturing method for manufacturing a main body, wherein the core pin is detachably attached to a fixed surface portion of the movable mold on which the core pin is provided, and after fitting a net to the core pin in advance, the core pin is attached to the fixed surface portion. At the same time, the molded product of the strainer body after injection molding is removed from the fixing surface part together with the core pin.