JPH11334504A - Shock absorbing material for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shock absorbing material for a vehicle at a low manufacturing cost with good dynamic and static behavior and ideal shock absorbing property. SOLUTION: A shock absorbing material E1 for a vehicle, formed of thermoplastic resin and integrally with blow molding, includes a mainbody 1 in an almost hollow cubic shape, one recessed rib 4a and the other recessed rib formed by recessing the mainbody 1 on its contact face 2 and its supporting face 3 opposed to each other and faced to each other and a joint put in contact with the ends of both recessed ribs. On the side wall 1a of the mainbody 1, an opening 8 is formed wherein the ratio of the opening area to all area is within 0.2%-15%. The opening 8 allows the improvement of dynamic behavior during destruction due to shock.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorber for a vehicle which is installed in a door or a body side panel of a vehicle such as an automobile to absorb a shock caused by a side collision.

[0002]

2. Description of the Related Art Heretofore, the following (a) and (b) have been known as a vehicle shock absorber for absorbing a shock caused by a side collision.

(A) As shown in FIG. 7, a shock absorber main body 1 cut out from a rigid polyurethane foam and manufactured.
A shock absorber 103 for a vehicle in which powder of the hard polyurethane foam is prevented from falling off by wrapping an outer peripheral surface of a hard resin foam 103a with a synthetic resin film 103b. One that absorbs the impact caused by a collision from the side by being provided inside (see Japanese Patent Application Laid-Open No. 7-32527).

(B) As shown in FIG. 8, a grid-like rib 20 is provided inside a substantially box-shaped outer shell 201 having one open side.
A synthetic resin-made vehicle shock absorber 200 integrally formed by injection molding and having 2a, as described in (a) above.
In the same manner as above, a shock absorber from a side impact is absorbed by being provided between the outer plate of the door and the interior material (see JP-A-8-66981).

[0005]

However, among the above prior arts (A), since the synthetic resin film is wrapped around the shock absorber main body cut out from the rigid polyurethane foam, the number of processing steps is large. However, there is a problem that the mass productivity is inferior and the cost is increased. Further, foamed polyurethanes have elasticity in compression properties and tend to have insufficient static behavior for efficiently absorbing impact force, though depending on the type of foamed polyurethane. In addition, there is also a problem that water enters from the sliding portion of the glass of the door and the like, and the polyurethane foam absorbs the water, so that the original repulsion cannot be obtained.

[0006] In the method (b), when the crushed piece is broken by an impact at the time of collision, a sharp corner is formed on the crushed piece, which may cause harm to a human body. In addition, since the maximum load at the time of structural destruction is high and a large reaction force is generated, it is difficult to ensure occupant safety sufficiently, and the dynamic behavior is poor. Further, when the average thickness is changed in order to adjust the shock absorbing performance of the vehicle shock absorber, the mold used for injection molding must be changed, and it takes time and cost to manufacture the mold. There is a problem.

[0007] The present invention has been made in view of the above-mentioned problems of the prior art, and has excellent static behavior for efficiently absorbing an impact force. It has ideal shock absorption characteristics with a small load and so-called good dynamic behavior.It also excels in mass productivity, and it is easy to change the average thickness to adjust the shock absorption performance. It is an object of the present invention to realize a shock absorber for a vehicle that can be used.

[0008]

In order to achieve the above object, a vehicle impact absorber according to a first aspect of the present invention is provided in a door or a body side panel to absorb an impact due to a side impact. The shock absorber for a vehicle, which is made of a thermoplastic resin integrally formed by blow molding, and has a substantially hollow cubic-shaped main body, and a contact surface and a support surface of the main body facing each other facing the other. One rib and the other concave rib formed by being depressed, and a joint portion in which the tip of the biconcave rib abuts, and the side wall of the main body has a ratio of an opening area to an entire area of the side wall ( An opening having an aperture ratio within a range of 0.2% to 15% is formed.

Furthermore, the thermoplastic resin, or the elastic modulus used as within the scope of 5000kg / cm ² ~25000kg / cm ² flexural or range an average thickness of the vehicular shock absorber 1mm~5mm Within.

[0010]

[Function] Since it is integrally molded by blow molding, it excels in mass productivity, and therefore has the advantage that the manufacturing cost is low and the shock absorption performance can be easily adjusted over a wide range by changing the wall thickness. However, there is a tendency that the maximum load at the time of causing structural failure is high and the dynamic behavior is not sufficient. Therefore, the above-mentioned drawback is compensated for by providing an opening having an opening ratio in the above range on the side wall.

As a result, it is possible to realize a low-cost vehicle shock absorber having ideal shock absorption characteristics in which both static behavior and dynamic behavior are good.

[0012]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic perspective view showing an embodiment of a vehicle shock absorber according to the present invention, and FIG.
It is a schematic cross section along a line. The vehicle shock absorber E ₁
It is made of a thermoplastic resin integrally formed by blow molding, and is formed by recessing a substantially hollow cubic body 1 and a contact surface 2 and a support surface 3 of the body 1 facing each other toward the other. One of the concave ribs 4a and the other concave rib 4b is provided, and a joint 4c is formed in which the tips of the biconcave ribs 4a and 4b abut. Further, a peripheral edge R chamfered portion 5 is formed at a peripheral portion of the contact surface 2 except for a corner portion,
A corner R chamfer 6 is formed at the corner of the contact surface 2.

A parting line 7 at the time of blow molding appears substantially in the middle between the contact surface 2 and the support surface 3.

The vehicle shock absorber for E ₁ which is integrally formed by blow molding is excellent in mass productivity, therefore, a good and inexpensive and high energy absorption as compared with the case of using a foamed polyurethane or the like It exhibits static behavior, but tends to have insufficient dynamic behavior due to a large maximum load when destroyed by the impact of a collision. For ideal shock absorbing characteristics to eliminate such drawbacks, ranging from 0.2% to 15% of the total area of the side wall to the side wall (peripheral wall) 1a of the main body 1 of the vehicle shock absorber for E ₁ An opening 8 having an opening area of not more than is provided.

[0016] the main body 1 of the vehicle shock absorber for E ₁ forms an opening 8 of the opening ratio, while maintaining good static behavior specific to vehicle shock absorber for by blow molding, the dynamic behavior It is possible to obtain a very ideal shock absorbing property close to that of a foamed polyurethane filling.

[0017] Figure 3 is an impact of the impact absorbing characteristics of a vehicle shock absorber for E ₁ perforated according to this embodiment, foamed polyurethane filling of a vehicle shock absorber and imperforate vehicle shock absorber by blow molding It is a graph compared with the absorption characteristics.
Vehicle shock absorber for E ₁ according to the present embodiment as shown by the solid line curve A _1, the value of the initial load a ₁ is a suitable level, the subsequent change in the flat, yet maximum load b ₁
No large difference between the value and the value of the initial load a _1, having an ideal shock-absorbing properties. On the other hand, a blow-molded vehicle shock absorber A ₂ having no opening (non-porous).
Although the value of the initial load a ₂ is the appropriate and subsequent change flat, poor high dynamic behavior is maximum load b _2.
In addition, shock absorber A ₃ for vehicles filled with polyurethane foam.
Is not much different between the maximum load b ₃ and the initial load a ₃ ,
It has the disadvantage that the gradient to the initial load a ₃ is gentle and the range of elastic deformation is wide, and therefore the amount of energy absorption is small and the static behavior is poor.

Regarding the aperture ratio of the opening 8 of the side wall 1a,
As described above, it is appropriate that the area is in the range of 0.2% to 15% of the entire area of the side wall 1a. If the ratio of the opening area is less than 0.2%, the effect of suppressing the maximum load is insufficient, and the reaction force at the time of breaking due to the impact of a collision is large, which is dangerous for the occupant. Further, when the ratio of the opening area is 15% or less, the initial load is reduced and buckling is caused at an early stage. If buckling occurs, it will be completely crushed and cannot absorb the impact force.

As described above, according to the present embodiment, it has ideal shock absorption characteristics excellent in both dynamic behavior and static behavior, and therefore has extremely high performance and is superior in mass productivity. A low-cost manufacturing shock absorber for vehicles can be realized.

In the present invention, as the thermoplastic resin,
Polyolefins such as polyethylene and polypropylene, styrene resins such as polystyrene and ABS resins, polyester resins such as polyethylene terephthalate, polyamides and the like, which have high mechanical strength such as rigidity are used.

Particularly, the flexural modulus is 5000 kg / cm ^2.
It is desirable to use one within the range of ２５25000 kg / cm ² .

If the flexural modulus is less than 5000 kg / cm ^2, it is too soft and is deformed by impact,
On the other hand, if it is larger than 25,000 kg / cm ² , it will be too hard and will be damaged by impact, and it will be impossible to obtain sufficient impact absorption performance as a vehicle impact absorber.

The average thickness of the vehicle shock absorber is 1 m.
It is desirable to be within the range of m to 5 mm. Particularly preferably, it is 1.5 mm to 3 mm. If the average thickness is less than 1 mm, the material may be deformed by absorbing an impact without absorbing the impact. Conversely, if the average thickness is more than 5 mm, the impact may not be absorbed.

Further, when the ratio of the area of the contact surface is set to 70% or more of the projected area projected in the direction perpendicular to the contact surface, the impact load is dispersed and the shock absorbing performance is improved.

Here, an example of use of the vehicle shock absorber according to the present invention will be described.

[0026] Figures 4 and 5 show the case where a 1 and a vehicle shock absorber for E ₁ shown in FIG. 2 according to the present invention in an automobile door, the inner panel 32 of the door 30 of a vehicle such as an automobile and a portion corresponding to the occupant's chest and lumbar sitting in the seat 33 between the door trim 31, a vehicle shock absorber for E ₁ are arranged respectively. Vehicle shock absorber for E _1, although in the one for those with lumbar for chest protection shape different support surface 3 side Both contacts the inner panel 32, contacts the contact surface 2 is the door trim 31 It is attached in the state where it did.

It is needless to say that the body side panel of the vehicle can be installed in the same manner as the door described above.

[0028]

EXAMPLES (Example 1) Polypropylene (manufactured by Nippon Polychem, grade: EC-9, flexural modulus 12000 kg /
cm ² , JISK-7113)
And a vehicle shock absorber having the same shape as that shown in FIG. 2 is manufactured by blow molding, and the opening ratio of the opening is 0.1%.
About 3.5% and 15.2%, the compression strain by collision was examined by the following test methods. FIG. 6 shows the result.

Outer shape of shock absorber for vehicle: length = 100 mm, width = 100 mm height = 50 mm average thickness: 2.5 mm Test method Impactor: has a flat surface of 80 mm × 160 mm. Impact speed: 30 km / h Atmospheric temperature: normal temperature Measurement result: Absorbed energy is drawn as a hysteresis curve.

The curve B _{1 in} FIG. 6 shows the shock absorption characteristics of the sample having an aperture ratio of 3.5%. The difference between the initial load and the maximum load was obtained without the initial load value being too high or too low. Is small, and the transition between them is flat, and therefore close to the ideal curve. However, the impact absorption characteristics of the sample aperture ratio of 0.1% as indicated by the curve B ₂ of FIG. 6 is large maximum load, close to that of a by nonporous a shock absorber for a vehicle according to the blow molding dynamic behavior Is shown. The curve B _{3 in} FIG.
The sample with an aperture ratio of 15.2% indicated by has an initial load that is too low, a large maximum load, and poor dynamic behavior. This is presumed to be due to insufficient rigidity as a whole because the opening area is too large.

The same experiment as described above was conducted by changing the opening ratio of the opening on the side wall in various ways.
It has been found that within the range of 15%, good impact absorption characteristics excellent in both dynamic behavior and static behavior can be obtained.

[0032]

Since the present invention is configured as described above, the following effects can be obtained.

Since the shock absorber for a vehicle is integrally formed by blow molding, it can excel in mass productivity and significantly reduce the manufacturing cost.

Since the maximum load at the time of structural destruction tends to increase in the vehicle shock absorber integrally formed by blow molding as described above, the dynamic shock can be obtained by providing an opening having a predetermined opening ratio on the side wall. Improve dynamic behavior.

As a result, it is possible to realize an inexpensive impact absorber for a vehicle, which has both good static behavior and dynamic behavior, and therefore has high performance and is inexpensive.

Further, since the average thickness of the vehicle shock absorber can be easily adjusted only by changing the thickness of the parison, the shock absorbing performance of the vehicle shock absorber can be adjusted in a short time and at low cost. Can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of one embodiment of a vehicle shock absorber according to the present invention.

FIG. 2 is a schematic sectional view taken along line AA of FIG.

FIG. 3 is a graph comparing the shock absorbing characteristics of the vehicle shock absorber of FIG.

FIG. 4 is an explanatory view showing an example of use of the vehicle shock absorber according to the present invention.

FIG. 5 is a schematic sectional view of a door in one usage example shown in FIG. 4;

FIG. 6 is a graph showing shock absorption characteristics when the aperture ratio of the side wall of the vehicle shock absorber is changed.

FIG. 7 is a schematic cross-sectional view of a door showing an example of a vehicle shock absorber provided inside a conventional door.

FIG. 8 is a schematic perspective view of a door showing another example of a conventional vehicle shock absorber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 2 Contact surface 3 Support surface 4a, 4b Concave rib 4c Joining part 5 Peripheral R chamfered part 6 Corner R chamfered part 7 Parting line 8 Opening 30 Door 31 Door trim 33 Sheet

Claims (4)

[Claims] An impact absorber for a vehicle, which is provided in a door or a body side panel to absorb an impact due to a collision from a side surface, and is made of a thermoplastic resin integrally formed by blow molding. A body having a substantially hollow cubic shape, one concave rib and the other concave rib formed by respectively depressing the opposing contact surface and support surface of the main body toward the other, and the tip of the biconcave rib. An opening having a contact portion, wherein a ratio of an opening area to a total area of the side wall is in a range of 0.2% to 15% in a side wall of the main body. Shock absorber for vehicles. 2. The thermoplastic resin has a flexural modulus of 5,000.
The vehicle shock absorber according to claim 1, characterized in that those within the range of ^{kg / cm 2 ~25000kg / cm 2} . 3. An average thickness of the shock absorber for a vehicle is 1 mm.
The shock absorber for vehicles according to claim 1 or 2, wherein the distance is within a range of from 5 to 5 mm. 4. The vehicle according to claim 1, wherein an area ratio of the contact surface is 70% or more of a projection area projected in a direction perpendicular to the contact surface. For shock absorber.