JP2000296759A - Seat belt slip joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize generating stress by progress of contraction of resin under a high temperature condition, and to provide excellent shape/performance holding capacity by cutting out a shoulder part of a resin guide part positioned in the shoulder part of an insert metal fitting embedding base of the resin guide part injectively molded by wrapping a part of an insert metal fitting. SOLUTION: An insert metal fitting 10 is composed of an installing part to a center pillar and an embedding base wrapped with resin, and a resin guide part 20 covers the embedding base of the insert metal fitting 10. A cutout part 21 is arranged in a shoulder part of the resin guide part 20 positioned in the shoulder part of the insert metal fitting 10. Such a cutout part 21 is arranged so that the shoulder part of the embedding base of the insert metal fitting 10 is exposed, the cutout quantity is desirably set to 10% to 100% of a resin guide part height H, and is particularly desirably cut out up to almost half of the resin guide part height H.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat belt slip joint for an automobile, and more particularly, to a resin seat belt slip joint containing an insert fitting which does not crack for a long time even at a high temperature inside the vehicle.

[0002]

2. Description of the Related Art Many conventional seat belt slip joints for automobiles cover a metal around with a thermoplastic resin as disclosed in Japanese Patent Application Laid-Open No. 7-329710.
Seat belt slip joints, which are interior parts of automobiles, can become quite hot due to the solar radiation in summer, and therefore, the seat belt slip joints need to maintain shape retention and performance at high temperatures for a long time.

[0003]

In a seat belt slip joint obtained by injection molding a resin around a metal, a large stress is generated in the seat belt slip joint due to molding shrinkage of the resin. Further, when a crystalline resin is used in the resin portion, when heat is applied to the seat belt slip joint, the seat belt slip joint further contracts, and a larger stress is generated.

For this reason, in the conventional seat belt slip joint, stress destruction may occur in the resin portion particularly in a high temperature environment in summer.

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention provides a highly reliable automotive seat belt slip joint which suppresses the stress generated due to the progress of resin shrinkage under high temperature conditions, is excellent in shape retention and performance retention, and is more reliable. The purpose is to:

[0006]

The seat belt slip joint of the present invention, which has been made to achieve the above object, comprises:
A description will be given with reference to FIGS.
An automotive seatbelt slip joint comprising an insert fitting 10 (see FIG. 2) including an attaching portion 11 and an embedded base portion 12 and a resin guide portion 20 formed to wrap a part thereof.
Guide portion 2 located on the shoulder of embedded base 12
The shoulder of 0 is cut off.

The present inventor has conducted intensive studies on the stress generated by the progress of resin shrinkage under high-temperature conditions in a seat belt slip joint made of a resin guide portion that is injection-molded so as to wrap the embedded base of the insert fitting. As a result, it has been found that particularly large stress is generated at the shoulder of the resin guide portion 20 located at the shoulder of the embedded base portion 12 of the insert fitting 10, and the present invention has been achieved.

That is, according to the seat belt slip joint of the present invention, the shoulder portion of the resin guide portion 20 located on the shoulder portion of the embedded base portion 12 of the insert fitting 10 has
By providing the notch 21 (see FIG. 1) so that the shoulder of the embedded base 12 of the insert fitting 10 is exposed, the stress generated on the shoulder due to the progress of resin shrinkage under high temperature conditions is reduced. It can be dispersed and released to other parts, and the maximum generated stress can be kept low.

Further, in the seat belt slip joint of the present invention, it is preferable to provide an anchor hole 13 near the shoulder of the embedded base 12 of the insert fitting 10. Thereby, the resin guide portion 2 which is lowered by providing the cutout portion 21 in the resin guide portion 20 is reduced.
The adhesive strength to the zero insert metal fitting 10 can be supplemented.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to FIGS. 1 to 4 showing one embodiment of the present invention. In addition,
FIG. 1 is a perspective view of a seat belt slip joint, and FIG.
Is a perspective view of the insert fitting, FIG. 3 is a rear view of the seat belt slip joint, and FIG. 4 is a side view of the seat belt slip joint.

The seat belt slip joint of the present invention is mounted on a center pillar of an automobile, and the seat belt passes through the pillar from the retractor and appears in the vehicle from a position near the shoulder, and the opening of the seat belt slip joint is opened. The belt moves smoothly through the section 31 (see FIG. 3).

This seat belt slip joint is
It is composed of an insert fitting 10 serving to support the load from the seat belt and assembling it to the center pillar, and a resin guide 20 for sliding with the belt.

The resin used for the resin guide section 20 is polyethylene, polypropylene, polystyrene, A
BS, polyvinyl chloride, polyamide, polyacetal,
Polycarbonate, modified polyphenylene ether, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyimide, polyamide imide, polyarylate, polysulfone, polyether sulfone, polyether ether ketone, liquid crystal polymer, polytetrafluoroethylene, thermoplastic elastomer, etc. Resins can be used, but any thermoplastic resin can be used as long as normal injection molding is possible. In particular, polyacetal resin is preferably used in the present invention because it has high heat resistance, excellent mechanical properties, and excellent sliding characteristics. The polyacetal resin to be used may be a homopolymer or a copolymer, and particularly preferably has a melt flow index of 1 to 50 g / 10 minutes as measured by ASTM D1238. It is preferable that a weather-resistant formulation is applied in consideration of direct sunlight. In addition, the bending elastic modulus of the polyacetal resin is A
The value measured by STM D790 is 30,000 kg
/ Cm ² or less.

For the purpose of improving heat resistance, mechanical strength, etc., an inorganic or organic filler can be added to the resin as required. Suitable fillers include glass fiber, carbon fiber, metal fiber, aramid fiber, potassium titanate, asbestos, silicon carbide, ceramic, silicon nitride, barium sulfate, calcium sulfate, kaolin, clay, pyrophyllite, bentonite, cellite Site, zeolite, mica, mica, nepheline sinite, talc, atalpargite, wollastonite, PMF,
Reinforced filling of ferrite, calcium silicate, calcium carbonate, magnesium carbonate, dolomite, zinc oxide, titanium oxide, magnesium oxide, iron oxide, molybdenum disulfide, graphite, gypsum, glass beads, glass balloon, quartz, quartz glass, etc. Materials. Two or more of these reinforcing fillers can be used in combination, and if necessary, they can be used after being pretreated with a silane-based or titanium-based coupling agent.

As shown in FIG. 2, the insert fitting 10 includes a mounting portion 11 for mounting on a center pillar and an embedded base 12 which is wrapped with resin. In FIG. 2, the embedded base is bent to increase the strength of the insert fitting, but this is not a limitation of the present invention.

As shown in FIG. 1, a resin guide portion 20 is provided.
Covers the embedded base 12 of the insert fitting 10. A notch 21 is provided at the shoulder of the resin guide 20 located at the shoulder of the insert fitting 10. The notch 21 is provided so that the shoulder of the embedded base 12 of the insert fitting 10 is exposed, and the notch amount is 10% of the height H of the resin guide portion.
Preferably, it is set to 100%, and it is particularly preferable to cut out to almost half of the height H of the resin guide portion as shown in FIG.

It is preferable that the notch 21 be invisible on the surface serving as the design surface, and is formed on the back surface side. It is also preferable to cover the notch 21 with, for example, a seat belt slip joint cover that is a separate component.

In the seat belt slip joint of the present invention, the notch 21 as described above is provided at the shoulder of the resin guide portion 20 to suppress the maximum stress generated by the progress of resin shrinkage under high temperature conditions. It has a great effect on extending the life under high temperature conditions.

On the other hand, if the notch 21 as described above is provided in the resin guide portion 20, the adhesive strength of the resin guide portion 20 to the insert fitting 10 is reduced depending on the cutout amount, and the resin shrinks. As the process proceeds, there is a concern that the resin guide portion 20 may be separated from the insert fitting 10. For this reason, it is preferable to provide an anchor hole 13 in the insert fitting 10 for joining a resin portion covering the front and back surfaces of the insert fitting 10. Such an anchor hole 1
3 is preferably arranged in a well-balanced manner, and is most preferably located in the vicinity of the shoulder of the embedded base 12 from the viewpoint of reinforcing the adhesive strength and reducing the generated stress.

The number and size of the anchor holes 13 are determined by the degree of the decrease in the adhesive strength due to the notch amount of the notch 21 provided in the resin guide 20 and the degree of the decrease in the rigidity of the insert fitting 10 due to the formation of the anchor hole. It can be appropriately designed in consideration of the above.

More specifically, as shown in FIG. 5, for example, when notch near 100% of the height of the resin guide portion,
As shown in FIG. 6, it is preferable to increase the number of anchor holes 13 of the insert fitting 10 to reinforce the bonding strength sufficiently. Even in this case, the number of the anchor holes 13 is preferably set to a maximum of about eight so as not to significantly reduce the rigidity of the insert fitting 10.

[0022]

The present invention will be described in more detail with reference to the following examples, which do not limit the present invention.

(Embodiment 1) FIG. 7 shows a seat belt slip joint of this embodiment. As shown in FIG. 8, the insert fitting 10 of this embodiment has an anchor hole 1 of φ4.
3 are provided in two places near the shoulder and two places in the center, and the thickness is 3.2 mm.

The cutout amount of the resin guide portion 20 is provided on the back side up to a height of 15 mm from the shoulder portion, and further a meat steal 71 is provided to make the thickness of the resin guide portion uniform at 3 mm. As the resin, a polyacetal copolymer having a weather resistance of 4 g / 10 min according to a melt flow index (ASTM D1238) was used.

With respect to the seat belt slip joint of the present embodiment, the simulation when the resin guide portion shrinks by 0.3% under the condition of an ambient temperature of 120 ° C. was evaluated by using CAE (Computer Edit Engineering) to determine the maximum generated stress and the maximum. The location where the stress occurred was calculated. Table 1 shows the evaluation results.

(Embodiment 2) FIG. 9 shows a seat belt slip joint of this embodiment. In the insert fitting 10 of this embodiment, as shown in FIG. 10, two anchor holes 13 of φ4 are provided at the center, and the thickness is 3.2 m.
m. Other dimensions, shapes and resins to be used are described in Example 1.
Is the same as

With respect to the seat belt slip joint of this embodiment, the maximum generated stress and the maximum stress generation location were calculated using CAE as in the first embodiment. Table 1 shows the evaluation results.

Comparative Example 1 FIG. 11 shows a seat belt slip joint of this comparative example. As shown in FIG. 12, the insert fitting 10 of this comparative example is provided with two φ4 anchor holes 13 at the center and has a thickness of 3.2.
mm. Other dimensions, shapes, and resins to be used are the same as those of the first embodiment, but the notch of the resin guide portion 20 is not provided.

With respect to the seat belt slip joint of this comparative example, the maximum generated stress and the maximum stress generation location were calculated using CAE as in Example 1. Table 1 shows the evaluation results.

[0030]

[Table 1]

As shown in Table 1, in Comparative Example 1 having the conventional shape, a very large maximum stress was generated at the shoulder.
In the seat belt slip joint according to the present invention, the maximum stress is generated inside the anchor hole or at the root of the notch, and the value is less than half of Comparative Example 1.

[0032]

As described above, the seat belt slip joint of the present invention has the following effects. (1) By providing a notch at the shoulder of the resin guide located at the shoulder of the base of the insert, the maximum stress generated by the progress of resin shrinkage under high temperature conditions can be kept low. it can. For this reason, the life until the occurrence of cracks due to creep over a long period of time can be significantly extended, and a more reliable automotive seat belt slip joint can be obtained. (2) In particular, in the case where an anchor hole is provided near the shoulder of the embedded base of the insert fitting, the adhesion of the resin guide to the insert fitting, which is reduced by the provision of the notch in the resin guide, is reduced. The strength can be supplemented, and the reliability is further improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a seat belt slip joint of the present invention.

FIG. 2 is a perspective view showing an insert fitting of the seat belt slip joint of FIG. 1;

FIG. 3 is a rear view of the seat belt slip joint of FIG. 1;

FIG. 4 is a side view of the seat belt slip joint of FIG. 1;

FIG. 5 is a perspective view showing another example of the seat belt slip joint of the present invention.

FIG. 6 is a perspective view showing an insert fitting of the seat belt slip joint of FIG. 5;

FIG. 7 is a perspective view illustrating a seat belt slip joint according to the first embodiment of the present invention.

FIG. 8 is a perspective view showing an insert fitting of the seat belt slip joint according to the first embodiment of the present invention.

FIG. 9 is a perspective view illustrating a seat belt slip joint according to a second embodiment of the present invention.

FIG. 10 is a perspective view showing an insert fitting of the seat belt slip joint according to the second embodiment of the present invention.

FIG. 11 is a perspective view showing a seat belt slip joint of Comparative Example 1.

FIG. 12 is a perspective view showing an insert fitting of the seat belt slip joint of Comparative Example 1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Insert metal fitting 11 Insert metal mounting part 12 Insert metal fitting embedding base 13 Anchor hole 20 Resin guide part 21 Notch part provided in resin guide part 31 Opening part for passing seat belt 71 Meat steal

Claims (3)

[Claims] 1. An automobile seat belt slip joint comprising an insert fitting comprising an attachment portion and an embedded base, and a resin guide portion molded so as to wrap a part thereof, wherein a shoulder portion of the embedded base of the insert fitting is provided. A seat belt slip joint for an automobile, characterized in that a shoulder portion of a resin-made guide portion is cut off. 2. The seat belt slip joint according to claim 1, wherein an anchor hole is provided in the vicinity of a shoulder portion of the base of the insert fitting. 3. The seat belt slip joint according to claim 1, wherein the resin guide portion is made of polyacetal.