JPH10250513A - Impact absorbing body for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an impact absorbing body for vehicle which is integrated through blow molding and made of a thermoplastic resin which is excellent in mass production and capable of easily changing the mean wall thickness to regulate the impact absorbing performance. SOLUTION: One die 21 and the other die 22 are opened, the thermoplastic resin is melted by an extruder, and a cylindrical parison is extruded from its extrusion head 24, and arranged between the dies 21, 22. Then, the dies are closed, the parison is recessed from its both sides by a projection part 21a for forming a rib of one die 21 and a projection part 22a for forming a rib of the other die 22, and its tip part is abutted to form a joined part 4c, and the parison 23 is held by a pinch-off part of the dies 21, 22. Then, the pressurized fluid is introduced into the parison, and expanded along a cavity, and an impact absorbing body for vehicle is integrated through blow molding. Finally, the impact absorbing body for vehicle is taken out after it is cooled in the dies 21, 22.

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. 9, a shock absorber main body 1 cut out from a rigid polyurethane foam.
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. 10, a grid-like rib 2 is provided inside a substantially box-shaped outer shell 201 having one open side.
An impact absorber 200 for a vehicle made of synthetic resin integrally formed by injection molding and having an inner surface 02a between the outer plate of the door and the interior material as in (a) described above. (See Japanese Patent Application Laid-Open No. 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.

[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, when changing the average thickness 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.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has an advantage that mass productivity can be improved and an average thickness can be easily changed for adjusting shock absorbing performance. It is an object of the present invention to realize a vehicular shock absorber that can perform the following.

[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 of the concave ribs and the other concave rib formed by being depressed, and a joint portion in which the tips of the biconcave ribs are in contact with each other.

A vehicle shock absorber according to a second aspect of the present invention is a vehicle shock absorber that is provided in a door or a body side panel to absorb a shock due to a side impact, and is integrally formed by blow molding. Made of a thermoplastic resin, and a substantially hollow cubic body,
A concave rib formed by depressing one of a contact surface and a support surface of the main body facing each other toward the other, and a joint portion in which a tip end of the concave rib contacts the other inner surface. It is characterized by having.

Preferably, a corner R chamfer is formed at a corner of the support surface, and a periphery R chamfer is formed at a periphery of the support surface excluding the corner.

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 2mm~5mm Within.

In addition, 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, or the hollow portion of the main body is sealed by closing the blow hole. .

[0013]

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. 2 is a schematic sectional view taken along line AA of FIG. The vehicle shock absorber E ₁ is made of a thermoplastic resin integrally formed by blow molding, and includes a substantially hollow cubic main body 1, and a contact surface 2 and a support surface 3 of the main body 1 facing each other. It has one concave rib 4a and the other concave rib 4b formed to be depressed toward the other, respectively, and a joint 4c in which the tips of the two concave 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, and a corner R chamfered portion 6 is formed at a corner of the contact surface 2.

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

FIG. 3 is a schematic sectional view of a portion similar to FIG. 1 showing another embodiment of a vehicle shock absorber according to the present invention. Vehicle shock absorber for E _2, of the abutment surface 12 and the support surface 13, which face each other, of the main body 11, the support surface 13 of the abutment surface 12 formed by depressing towards a cylindrical concave ribs 1
4 and a joint portion 14a in which the tip of the concave rib 14 is in contact with the inner surface of the contact surface 12. Since the remaining portions may be the same as vehicle shock absorber for E ₁ shown in FIGS. 1 and 2 and a description thereof will be omitted.

[0017] Contrary to the above, the contact surface 12
May be depressed toward the support surface 13 to form a concave rib.

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.

In particular, 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 2 m.
It is desirable to be within the range of m to 5 mm. If the average thickness is less than 2 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, so that the impact absorbing performance is improved.

In addition, if the hollow portion of the main body is sealed by sealing the blowing hole formed by the blowing means, the shock absorbing performance is further improved.

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

FIG. 4 and FIG. 5 shows a 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.

Next, a manufacturing method of the vehicular shock absorber according to the present invention, will be described as an example the case of blow molding a vehicle shock absorber for E ₁ shown in FIGS.

As shown in FIG. 6, one mold 21 and the other mold 22 are opened, the thermoplastic resin is melted by an extruder (not shown), and a cylindrical parison 23 is extruded from the extrusion head 24. , Are arranged between the two molds 21 and 22.

After the above, the mold is closed, and the paris 23 is depressed from both sides thereof by the rib forming protrusions 21 a of the one mold 21 and the rib forming protrusions 22 a of the other mold 22, so that the tip ends. Are formed in contact with each other to form a joint 4c, and the paris 23 is
It is pinched between the pinch-off portions 1 and 22. If the joining portion 4c is welded, the shock absorbing performance is improved.

In this step, the opening of the tip end of the parison 23 is closed, and a predetermined amount of pressurized fluid is introduced by a blowing means or the like provided in the extrusion head 24, so-called pre-blowing is performed. Can be

After the above, pressurized fluid is introduced into the paris 23 by blowing means (not shown), and is expanded along the cavity, as shown in FIG. 7, to blow-mold the above vehicle shock absorber E _1. To be integrally molded.

[0032] After the above, after cooling to a temperature capable of taking out in the mold 21 and 22, it takes out the vehicle impact absorbing member E ₁ subjected to mold opening.

The vehicle shock absorber E ₂ shown in FIG.
In order to blow-mold the rib, a rib is formed in the other mold by projecting and deforming the paris so that its tip is brought into contact with the inner surface of the contact surface 12 to form the joint portion 14a. A split-type mold having a section is used.

[0034]

【Example】

(Example 1) Polypropylene (manufactured by Nippon Polychem, grade: EC-9, flexural modulus 12000 kg / cm ² , J
According to ISK-7113), FIG. 1 and FIG.
Was manufactured by blow molding, and the obtained vehicle shock absorber was subjected to a tensile tester (“TENSILON / STM” manufactured by AND Corporation).
-F1000BP "), the contact surface and the support surface were compressed from a direction deviated by 5 degrees, and the change in compression strain with respect to the compression load was measured. The result is shown by curve A in the graph shown in FIG.

Outer shape of vehicle shock absorber: length = 100 mm, width = 1
00 mm, height = 50 mm Radius of curvature of peripheral R chamfer: 10 mm Curvature radius of corner R chamfer: 25 mm Average thickness: 2.5 mm (Example 2) Peripheral R chamfer and corner R chamfer Except that no portion was formed, a vehicle shock absorber was manufactured by blow molding in the same manner as in Example 1, and the obtained vehicle shock absorber was measured for changes in compressive strain with respect to compressive load in the same manner as in Example 1. . The result is shown by curve B in the graph shown in FIG.

As is clear from the curves A and B shown in the graph of FIG. 8, the shock absorbers for vehicles of Examples 1 and 2 each have a compression load of about 580 kg / cm.
^{2. The} compressive strain changes linearly until it exceeds about 500 kg / cm ² , and the value is maintained at 20% or less, so that the shock absorbing performance is good and both are effective. .

In particular, in the case of the first embodiment in which the peripheral R-chamfered portion and the corner R-chamfered portion were formed at the peripheral edge and the corner other than the corner of the contact surface, respectively, the compressive load was about 600 kg / cm.
^{In 2} , the compression strain is greatly increased from about 20% to 60%, and the shock absorbing performance is better.

[0038]

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

Since integral molding is performed by blow molding, mass productivity can be surpassed, and manufacturing costs can be significantly reduced.

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 schematic sectional view similar to FIG. 2, showing another embodiment of a vehicle shock absorber according to the present invention.

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 an explanatory view showing one process during blow molding of the vehicle shock absorber according to the present invention.

FIG. 7 is an explanatory view showing one process during blow molding of the vehicle shock absorber according to the present invention.

FIG. 8 is a graph showing a relationship between a compressive load and a compressive strain in Example 1 and Example 2 in the vehicle shock absorber according to the present invention.

FIG. 9 is a schematic cross-sectional view of a door showing an example of a vehicle shock absorber provided in a conventional door.

FIG. 10 is a schematic perspective view of a door showing another example of a conventional vehicle shock absorber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1,11 Main body 2,12 Contact surface 3,13 Support surface 4a, 4b, 14 Concave rib 4c, 14a Joint 5 Peripheral R chamfer 6 Corner R chamfer 7 Parting line 21 One mold 21a , 22a Rib forming protrusion 22 Other mold 23 Parison 24 Extrusion head

Claims (7)

[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 impact absorber for a vehicle, comprising: a contact portion that abuts. 2. A shock absorber for a vehicle, which is provided in a door or a body side panel to absorb a shock 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, a concave rib formed by depressing one of a contact surface and a support surface of the main body facing each other toward the other, and a tip end of the concave rib is A shock absorber for a vehicle, comprising: a joining portion contacting the other inner surface. 3. A corner R-chamfered portion is formed at a corner of the support surface, and a peripheral R-chamfered portion is formed at a peripheral portion excluding the corner of the support surface. Item 1 or 2
The vehicle shock absorber according to any one of the preceding claims. 4. The thermoplastic resin has a flexural modulus of 5,000.
claims 1 to, characterized in that within the range of ^{kg / cm 2 ~25000kg / cm 2} 3 either 1
The shock absorber for vehicles according to the above item. 5. The average thickness of the shock absorber for a vehicle is 2 mm.
The shock absorber for a vehicle according to any one of claims 1 to 3, wherein the shock absorber is within a range of 5 to 5 mm. 6. The vehicle according to claim 1, wherein a ratio of an area of the contact surface is 70% or more of a projection area projected in a direction perpendicular to the contact surface. For shock absorber. 7. The shock absorber for a vehicle according to claim 1, wherein a hollow portion of the main body is sealed by sealing the blowing hole.