JPH11132909A - Resin structural component and degradation detecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the detection of the degree of deterioration in real material at the time when a structural component is exposed to real environmental hysteresis by providing a protrusion to a resin structural component and inspecting a deformation or a breakage of the structural component at the time when a predetermined load is exerted on the protrusion. SOLUTION: A resin protrusion 2 is provided for a resin intake manifold, which is a pipe-shaped resin component 1. A predetermined displacement or a load is given to the protrusion 2, and a reactive force or a displacement is measured before degradation. Then a reactive force or a displacement is measured at appropriate time intervals during periods of use to grasp the degree of degradation. In addition. as the number of the natural vibration of the protrusion 2 is measured, and a Young's modulus increases with the development of degradation, the number of the natural vibration of the protrusion 2 is continued after an appropriate period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The field of using structural parts made of resin. In particular, it can be used for engine parts in the automobile industry.

[0002]

2. Description of the Related Art As an example of the use of resin structural parts, in the field of automotive equipment, engine structural parts have been used because of advantages such as cost reduction by shortening processing steps, improvement of fuel efficiency by reduction of weight, and improvement of design flexibility. Resin conversion is in progress. Since a resin material is significantly deteriorated over time as compared with a conventional metal material, it is necessary to confirm sufficient durability reliability when commercializing the resin material. For this reason, after the deterioration of the material is advanced by a deterioration acceleration test or the like, the degree of deterioration is measured by, for example, a method shown in the literature 1) to grasp the progress speed of the deterioration, and a sufficient strength margin in consideration of the deterioration is obtained. At present, it is designed to have. References 1) Shichi, Y., Yamaguchi, H., Inoue, Y .: Application of Surface and Local Analysis to Automotive Materials, Nondestructive Inspection, Vol. 44, No. 9 (1995).

[0003]

In an automobile or the like, the progress of the deterioration greatly differs depending on each use environment. Especially, in the case of resin parts, the change and the variation are large, and if the design is made assuming the worst environment and the lower limit of the variation, the safety margin of the product becomes very large, and the profitability is increased. become worse. Therefore, when using resin structural parts, it is possible to monitor the progress of deterioration in each use environment and to accurately detect when the life of the product is approaching, and take appropriate measures such as replacement if necessary. Is most desirable.

[0004] However, the above-described method of measuring deterioration can be performed at the test piece level, but cannot be applied to a product that is actually operating. If cost is also taken into account, a method for easily ascertaining the degree of deterioration at the site is required.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, in a resin-made structural part constituting a machine or a structure used for an automobile, one part is previously set when molding with a resin.
One or a plurality of resin protrusions are provided on the part, and the deformation or destruction of the protrusion when a predetermined load is applied to the protrusion is examined, whereby the actual material when the part is exposed to the real environment history is examined. The degree of deterioration can be detected. In the resin-made structural component having the projection, the degree of deterioration of the component can be detected based on the magnitude of the reaction force when a predetermined displacement is applied to the projection. Alternatively, it is also possible to detect the degree of deterioration of the component based on the natural frequency of the projection when an impact is applied to the projection.

That is, as the thermal deterioration of the resin progresses,
Experiments have shown that the stiffness tends to be significantly higher. FIG. 7 shows a relationship between a standing time when a resin material is left in a high-temperature bath kept at a constant temperature to promote thermal deterioration and a change in longitudinal elastic coefficient. When the deterioration is promoted at a high temperature in the atmosphere, the longitudinal elastic modulus of the resin increases with time as shown in the figure. At the same time, the elongation at break decreases.

Therefore, when a predetermined force is applied to the protrusion as in the present invention, if the deterioration is progressing, the displacement of the protrusion is small, or the protrusion exceeds the breaking elongation and breaks.
The degree of the deterioration or the degree of the deterioration can be grasped by the degree of the deformation or the destruction. In addition, when a predetermined displacement is applied, if the deterioration is progressing, the value of the load required to apply the displacement increases or breaks beyond the breaking elongation. Then, the degree of deterioration can be grasped by this load value or destruction. Alternatively, it is possible to grasp the deterioration from the frequency of the protrusion. As the deterioration proceeds, the rigidity of the resin increases, so that the vibration frequency of the protrusion also increases. Therefore, it is possible to grasp the degree of deterioration from the measurement of the frequency of the protrusion.

According to the present invention, the degree of deterioration can be easily grasped at the time of inspection of the engine room.

[0009]

FIG. 1 shows a first embodiment of the present invention. FIG. 2 shows a cross-sectional shape. A resin-made intake manifold, which is a pipe-shaped resin part 1, is provided with a resin protrusion 2 of the present invention. This part supplies the air taken from outside to the cylinder of the car engine.
Since it is directly attached to the engine body and stored in the engine room, deterioration due to heat load and the like is severe in addition to mechanical loads such as vibration and thermal stress.

As the material, glass fiber reinforced nylon having excellent mechanical and thermal properties is generally used. When the engine is running, it is exposed to a temperature environment of up to about 120 ° C, which is extremely high for resin materials.
In particular, it is a component for which thermal degradation is a concern. Therefore, an attempt was made to improve the durability reliability by the present invention.

Although the intake manifold is made of resin here, it is needless to say that the same embodiment can be applied to other resin parts.

The reaction force or displacement when a predetermined displacement or load is applied to the projection 2 is measured in an undegraded state, and these are measured at appropriate time intervals during use to determine the degree of deterioration. Figure out. The degree of deterioration can also be grasped by measuring the natural frequency of the projection. That is, the longitudinal elastic coefficient increases as shown in FIG. 7 with the progress of deterioration, so that the natural frequency increases. Therefore, if the natural frequency is measured in an undegraded state and the measurement of the natural frequency of the projection is continued after an appropriate period, the progress of the deterioration can be grasped.

FIG. 3 shows a second example of the embodiment. FIG. 4 shows a sectional view. Two projections 2 are provided to oppose each other.
The height H and the interval L of the two projections are determined based on the data shown in FIG. In other words, two protrusions 2
The distance L is determined so that when the material is deformed until it comes into contact, it does not break in an undegraded state, but breaks at a stage where deterioration has progressed. When this projection is pressed during a periodical inspection or the like, and this projection is damaged, it is possible to grasp the state of deterioration of the component, such as when it is time to replace it.

FIG. 5 shows a plurality of pairs of protrusions 2 as described above.
It is provided. FIG. 6 is a sectional view. Here, three pairs of projections are used, but the same invention applies to more or less than three pairs.

The intervals L ₁ , L ₂ , L ₃ of the pairs are sequentially increased. When inspecting for deterioration, grab the pairs in order starting from the pair with the smallest distance. A thing with a large interval has a large displacement and a severe load. Therefore, the degree of deterioration can be grasped based on which pair of protrusions is damaged in order from the pair with the largest interval and which is damaged.

[0016]

As described above, according to the present invention, the state of deterioration of a resin part can be easily grasped, and the reliability of the part can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of a pipe-shaped resin component according to an embodiment of the present invention.

FIG. 2 is a sectional view of FIG.

FIG. 3 is a perspective view of a pipe-shaped resin part according to a second embodiment of the present invention.

FIG. 4 is a sectional view of FIG. 3;

FIG. 5 is a perspective view of a pipe-shaped resin part according to a third embodiment of the present invention.

FIG. 6 is a sectional view of FIG. 5;

FIG. 7 is a characteristic diagram showing that the longitudinal elastic modulus of a resin increases due to thermal degradation.

[Explanation of symbols]

1 ... a pipe-shaped resin part, 2 ... a resin protrusion, 3 ... a pair of resin protrusions.

Claims (1)

[Claims] The present invention relates to a resin-made structural part for a machine or a structure used in an automobile, which has one or a plurality of resin protrusions, and which deforms the protrusion when a predetermined force is applied to the protrusion. A resin structural part and a deterioration detecting method, wherein the degree of deterioration of the part is detected by destruction.