JPS5934484B2 - Synthetic resin molded product with synthetic resin insert - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a synthetic resin molded article having a synthetic resin insert.

Here, explanation will be given using an example of an assist grip as shown in FIG. 1, but the present invention is not limited to this.

Conventionally, assist grips have been molded from soft synthetic resin material with embedded spring steel inserts.

However, since spring steel is used as the insert, there are problems with high cost and weight. Therefore, the inventor of the present application,
An attempt was made to use a hard synthetic resin material as the insert. At this time, since the synthetic resin insert (hereinafter referred to as insert) 1 has low rigidity and is pressed downward by the flow of resin during molding, the insert 1 is unevenly distributed downward and molded. It is necessary to provide a boss 1a as shown in FIG. 4 to prevent uneven distribution of the insert 1 due to pressure.

However, since the boss 1a is not restricted from moving from side to side, the insert 1 is unevenly distributed in the lateral direction as shown in Fig. 5, and is sometimes exposed, causing problems in terms of appearance and feel when gripping. . Further, after molding, the soft synthetic resin portion 2 shrinks and the boss 1a is exposed as shown in FIG. 6, causing the same problem as described above. In addition, FIG. 3 is a cross-sectional view of the both end attachment parts lc of the assist grip, and the lower surface of the insert 1 needs to be covered to prevent the soft synthetic resin part 2 from contracting and exposing the insert 1, as described above. . However, in this case, when the insert 1 is tightened with the machine screw 4 when attaching it to the vehicle body panel 3, as shown in Fig. 7, the insert 1 causes a new phenomenon, making it impossible to obtain sufficient tightening force. screw 4
This causes a problem that the parts fall off from the vehicle body panel 3. In view of the above, the present invention provides a synthetic resin that does not cause uneven distribution of the insert during molding, does not expose the boss portion of the insert even when the soft synthetic resin portion contracts, and does not cause problems in terms of appearance and feel. An object of the present invention is to provide a method for producing a synthetic resin molded article by which a molded article can be obtained.

The gist of this invention is that when manufacturing a synthetic resin molded product consisting of a hard synthetic resin insert and a soft synthetic resin part in which the insert is buried, a fitting hole is formed in the longitudinal middle of the synthetic resin insert. By providing an appropriate number of bosses, forming set pins in the mold corresponding to each boss, and fitting the set pins into the fitting holes of the bosses, the synthetic resin insert can be floated in the cavity. A method for manufacturing a synthetic resin molded product, characterized in that molding is carried out while holding the product.

Hereinafter, a method according to an embodiment of the present invention will be explained based on FIGS. 8 to 10.

Hard synthetic resin insert (hereinafter referred to as insert)
5, and a soft synthetic resin portion 6 in which the insert 5 is embedded.

At this time, the material of the insert 5 is polypropylene,
The material for the soft synthetic resin portion 6 can be appropriately selected from polyethylene, soft vinyl chloride, foamed urethane, and the like. As shown in FIG. 9, the mounting portions 5c at both ends of the insert 5 form a lower end surface in which the central portion of the lower end protrudes from the surroundings, and an appropriate number of mounting portions are provided at the middle lower portion, as shown in FIGS. 8 and 10. A cylindrical boss 5a is formed. This boss 5a
It has a fitting hole 5b into which a set pin 7 can be fitted during molding to allow the insert 5 to float and be held within the cavity 8. In this way, since the insert 5 is held floating by the set pin 7 during molding, the insert 5 is exposed downward and unevenly from side to side during molding, and
Due to the contraction of the soft synthetic resin portion 6, the boss 5a of the insert 5
The lower end surface of the device will not be exposed.

In addition, since the central part of the lower end of the mounting part 5c of the insert 5 forms a lower end surface that protrudes from the surroundings, even if the soft synthetic resin part 6 contracts, the lower end face of the mounting part 5c will not touch the soft synthetic resin part 6. It is kept exposed at the same level as the road surface.

In the case of the mounting part with this structure, the lower surface of the insert 5 can directly contact the vehicle body panel 3 and be tightened with the machine screw 4, so no shearing phenomenon occurs in the insert 5, sufficient tightening force can be obtained, and of course, There is no possibility that the machine screw 4 will fall off from the vehicle body panel 3. Since the method for manufacturing a synthetic resin molded product of the present invention has the above-described configuration, the insert is not unevenly distributed during molding, and even if the soft resin part shrinks, the boss part of the insert is not exposed, and the appearance is improved. Moreover, it is possible to obtain a synthetic resin molded product that has no problems in terms of feel.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the assist grip, Fig. 2 is a partial sectional view of the assist grip that tends to cause problems, and Fig. 3 is a perspective view of the assist grip.
4 is a sectional view taken along the - line in FIG. 2, FIG. 5 is a sectional view of FIG. 4 with the insert unevenly distributed,
Figure 6 is a sectional view of the boss of the insert protruding from the soft synthetic resin part in Figure 4, Figure 7 is a sectional view of the mounting portion of Figure 3 in an installed state, and Figure 8 is an embodiment of the present invention. FIG. 9 is a partial sectional view showing the relationship between the assist grip and the mold in the method of 1, FIG. 9 is a sectional view taken along the line -- in FIG. 8, and FIG. 10 is a sectional view taken along the line X--X in FIG. 8. 5... (synthetic resin) insert, 5a...
... Boss, 5b ... Fitting hole, 5c ...
・Mounting part, 6...Soft synthetic resin part, 7...
...Set pin, 8...Cavity.

Claims (1)

[Claims] 1. When manufacturing a synthetic resin molded product consisting of a hard synthetic resin insert and a soft synthetic resin part in which the synthetic resin insert is embedded, a boss in which a fitting hole is formed in the longitudinal middle part of the synthetic resin insert In addition to providing an appropriate number of bosses, set pins are formed on the mold corresponding to each boss.
A method for manufacturing a synthetic resin molded product, characterized in that molding is carried out while holding the synthetic resin insert floating in the cavity by fitting the set pin into the fitting hole of the boss.