Automotive interior material and method of manufacturing the same

Abstract

An automotive interior material with high appearance quality and a method of manufacturing the same in the following configurations and steps: A door trim 1 (automotive interior material) has a flat portion 11 (main-body portion) covering a door panel and an armrest 12 protruding into the vehicle compartment. Molten resin material added with foaming agent is supplied into a cavity CV1 formed between a pair of molds 2, 3. Then, opening of the pair of molds 2, 3 by a predetermined amount causes the molten resin material in the cavity CV1 to foam. An upper surface 14 (vertical wall portion) of the armrest 12 is connected to the flat portion 11 and extends in a thickness direction of the flat portion 11. A surface of the upper surface 14 facing outward from the vehicle compartment is formed with a recessed portion 15. During a vehicle collision, an object in the vehicle presses the arm rest 12 formed on the door trim 1. Then the door trim 1 is broken and deformed in the recessed portion 15, so that the armrest 12 is crushed, thus absorbing an impact by a collision.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Japanese Patent Application No. 2006-211724 filed Aug. 3, 2006. The entire content of this priority application is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an automotive interior material and a method of manufacturing the same.

BACKGROUND

A door trim, a type of interior material, is attached onto a vehicle door inside the vehicle compartment. The door trim is usually formed with synthetic resin material, and an armrest is integrally formed on the surface of the door trim inside the vehicle compartment. The armrest is a shelf that supports the forearm of a vehicle occupant comfortably and is protruding into vehicle compartment by a predetermined amount. The armrest, during a vehicle collision, may hit an object in the vehicle compartment, thus causing some damage to the object.

To reduce damage to the object during a vehicle collision, there have been a conventional technique of forming a notched groove of a substantially triangular shape in cross section at a base portion of an armrest formed on a door trim, for example, as disclosed in Japanese Utility Model Laid-Open No. 6-6123 (FIG. 1 at page 5). The notched groove is formed on the surface of the door trim facing outward from the vehicle compartment, extending in the vehicle longitudinal direction. If the armrest is pressed by the object in the vehicle compartment during a vehicle collision, the notched groove is broken and the armrest is crushed while absorbing the collision energy. This enables to reduce damage to the object during a vehicle collision.

Recently, the need of vehicle weight reduction on the market has intensified and door trims are no exception. To reduce the vehicle weight, resin foam material has been used as a material for automotive interior materials, such as door trim and the like.

Inventors of the present invention, as described below, have attempted to use resin foam material to form a door trim capable of reducing damage to an object during a vehicle collision.

As shown in FIG. 6, a cavity CV is formed between an opposing movable mold 7 and stationary mold 8 which are disposed vertically. On the surface of the stationary mold 8 that forms the cavity CV, there is formed a protrusion portion 81 of a substantially triangular shape in cross section. The protrusion portion 81 is formed extending in a vertical direction to paper in FIG. 6.

As shown in FIG. 7, after the molten resin material SR added with foaming agent is supplied into the cavity CV, the movable mold 7 is moved away from the stationary mold 8 to open the movable mold 7 by a predetermined amount. This causes the molten resin material SR to foam and a door trim 9 is formed. An operation of opening the movable mold 7 by the predetermined amount to foam the molten resin material SR may be called core-back. At core-back, a notched groove 91 is formed by the protrusion portion 81 on the surface of the door trim 9 in contact with the stationary mold 8.

As shown in FIG. 7, a portion forming the notched groove 91 of the door trim 9 is smaller than any other portion in thickness. Accordingly, the portion forming the notched groove 91 has a reduced volume of resin material due to the reduced thickness and does not have sufficient thickness even after the resin material is foamed. In this case, on the surface of the door trim 9 in contact with the movable mold 7, a depression 92 is unavoidably formed at a location opposite to the notched groove 91. Formation of the depression 92 on a decorative surface of the door trim 9 (the surface in contact with the movable mold 7) will impair the appearance of the door trim 9.

SUMMARY

The present invention has been made in view of the aforementioned circumstances and its object is to provide an automotive interior material with good appearance quality and a method of manufacturing the same.

A method of manufacturing automotive interior material, the automotive interior material being mounted on a vehicle body inside the vehicle compartment and having a recessed portion of a thin-wall shape in cross section on a surface facing outward from the vehicle compartment, the automotive interior material being pressed by an object in a vehicle and deformed by the recessed portion so as to absorb an impact during a vehicle collision and the automotive interior material including a main body covering the vehicle body and a vertical wall portion connected to the main body and extending in a thickness direction of the main-body portion, the method including the steps of: providing a protrusion portion on a portion that forms the vertical wall portion of a mold and supplying molten resin material added with foaming agent into the mold; opening the mold by a predetermined amount in a main-body thickness direction after supplying the molten resin material into the mold to foam the molten resin material and to form the main body with a predetermined thickness; and forming the recessed portion for the vertical wall portion by the protrusion portion.

According to the present invention, the vertical wall portion extends in the main-body thickness direction (mold opening direction). Even though the recessed portion is formed in the vertical wall portion, this permits molten resin to foam sufficiently at other portions except the recessed portion when the mold is opened. Accordingly, no depression will be formed on a decorative surface of the automotive interior material.

Preferably, the present invention has the following configuration:

(1) The automotive interior trim member manufactured according to a manufacturing method of the present invention can reduce damage to an object in a vehicle. The automotive interior trim member manufactured according to a manufacturing method of the present invention forms no depression or the like on a decorative surface.

(2) Preferably, the automotive interior material is a door trim, and the vertical wall portion constitutes an upper surface of an armrest formed on the door trim. During a vehicle collision, a thin-wall portion is deformed by a pressure of an object, so that the armrest is crushed. This can reduce damage to the object without particularly changing the shape of the armrest.

According to the present invention, an automotive interior material with good appearance can be manufactured, because of no depression or the like on a decorative surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a door trim according to a first illustrative aspect seen from the interior side of the vehicle compartment;

FIG. 2 is a sectional view when a mold is filled with unfoamed molten resin to form a door trim shown in FIG. 1;

FIG. 3 is a sectional view when molten resin is foamed through the core-back of a mold shown in FIG. 2;

FIG. 4 is a sectional view when a mold is filled with unfoamed molten resin to form a door trim according to a second illustrative aspect;

FIG. 5 is a sectional view when molten resin is foamed through the core-back of a mold shown in FIG. 4;

FIG. 6 is a view showing a conventional technique and a sectional view when a mold is filled with unfoamed molten resin to form a thin-wall portion on a door trim; and

FIG. 7 is a view showing a conventional technique and a sectional view when molten resin is foamed through the core-back of a mold shown in FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED ILLUSTRATIVE ASPECTS

(First Illustrative Aspect)

Referring now to FIGS. 1 to 3, the first illustrative aspect according to the present invention will be described blow. The right side of a door trim 1 shown in FIG. 3 is the interior side of a vehicle compartment and a surface inside the vehicle compartment is a decorative surface. The door trim 1 according to the present illustrative aspect is a type of automotive interior material attached on the interior side of the vehicle compartment.

The door trim 1 according to the present illustrative aspect is molded by foaming synthetic resin material added with foaming agent. The synthetic resin material may use thermoplastic synthetic resin material such as polypropylene. The foaming agent may use bicarbonate such as sodium hydrogencarbonate, chemical foaming agent or the like.

The door trim 1 is not limited to the above, but is used for rear seat doors of a vehicle and is attached on a door panel of the rear seat doors (not shown) inside the vehicle compartment. The door panel corresponds to a vehicle body of the present invention.

As shown in FIG. 1, the door trim 1 has a flat portion 11 covering a door panel and an upper surface 14 connected to the flat portion 11 and extending in a thickness direction of the flat portion 11. The flat portion 11 corresponds to the main body of the present invention. The upper surface 14 corresponds to the vertical wall portion of the present invention.

As shown in FIG. 1, substantially in the center of the door trim 1, there is formed an armrest 12 expanding into the vehicle compartment. The armrest 12 is a shelf that supports the forearm of a rear-seat occupant comfortably. The upper surface 14 is the upper surface of the armrest 14.

As shown in FIG. 2, a pair of molds 2, 3 are disposed so as to face each other horizontally. Between the pair of molds 2, 3, a cavity CV1 is formed. The one mold 2 is a movable mold and forms a decorative surface of the door trim 1 (a surface inside the vehicle compartment), while the other mold 3 is a stationary mold and forms a surface of the door trim 1 facing outward from the vehicle compartment.

As shown in FIG. 2, the pair of molds 2, 3 have opposing surfaces 21, 31 for forming the flat portion 11, respectively. The opposing surfaces 21, 31 are substantially parallel to each other and extend vertically, respectively.

As shown in FIG. 2, horizontal surfaces 22, 32 for forming the upper surface 14 of the armrest 12 extends from the opposing surfaces 21, 31. The horizontal surfaces 22, 32 extend laterally so as to slightly tilt downward and extend in substantially parallel to each other.

As shown in FIG. 2, vertical surfaces 23, 33 for forming the front surface 13 of the armrest 12 extend from the horizontal surfaces 22, 32. The vertical surfaces 23, 33 extend obliquely downward, respectively.

As shown in FIG. 2, an end portion of the horizontal surface 32 facing outward from the vehicle compartment has an upward protruding protrusion portion 34 formed thereon. The protrusion portion 34 is formed on the horizontal surface 32 extending in a front/reverse direction of paper in FIG. 2.

The door trim 1 can be produced in the following processes:

First, molten resin material such as polypropylene added with foaming agent is injected and supplied into the cavity CV1 formed between the pair of molds 2, 3. At a predetermined period after the molten resin material is supplied into the cavity CV1, the one mold 2 (movable mold) is moved away from the other mold 3 (stationary mold) (core-back of the mold 2). This allows the pair of molds 2, 3 to open, by a predetermined amount, in a thickness direction of the flat portion 11 (a direction indicated by an arrow in FIG. 2). Then, as shown in FIG. 3, an internal pressure of the cavity CV1 lowers to foam the molten resin material with which the cavity CV1 is filled, thus forming the door trim 1.

As shown in FIG. 3, the foamed molten resin material is formed to have a predetermined thickness by the opposing surfaces 21, 31 and the vertical surfaces 23, 33 of the pair of molds 2, 3. This forms the flat portion 11 and the front surface 13 of the armrest 12.

As shown in FIG. 3, the upper surface 14 of the armrest 12 is formed by the horizontal surfaces 22, 32 of the pair of molds 2, 3. In other words, the upper surface 14 of the armrest 12 is formed by a region sandwiched by the horizontal surfaces 22, 32 in the pair of molds 2, 3.

On one end of the upper surface 14 of the armrest 12 facing outward from the vehicle compartment, there is formed a recessed portion 15 recessed upward. The recessed portion 15 is formed by the protrusion portion 34 provided on the mold 3 (stationary mold). The recessed portion 15 is formed in a surface of the door trim 1 facing outward from the vehicle compartment. The bottom of the recessed portion 15 is a thin-wall portion in which part of the door trim 1 is formed into a thin-wall shape.

The recessed portion 15 is formed extending in a lengthwise direction of the armrest 12 (vehicle longitudinal direction). The upper surface 14 of the armrest 12 extends in such a direction as to approximately meet the opening direction of the mold 2 (thickness direction of flat portion 11). In the opening direction of the mold 2 (core-back direction) before and after the core-back, a ratio of change in a length of the upper surface 14 of the armrest 12 is lower than that in a thickness of the flat portion 11 of the door trim 1.

Accordingly, a surface (decorative surface) of the upper surface 14 of the armrest 12 inside the vehicle compartment will have no depression resulting from shortage of molten resin. The reason is that a portion forming the recessed portion 15 in the upper surface 14 of the armrest 12 has little molten resin, while other portions except the recessed portion 15 has a sufficient amount of molten resin, so that molten resin can be sufficiently foamed at other portions except the recessed portion 15, thus minimizing an influence of the recessed portion 15.

As shown in FIG. 3, a portion surrounded by the horizontal surfaces 22, 32 is formed so as to be longer than a distance (core-back amount) for retracting the mold 2 (movable mold). This allows molten resin to be foamed at both ends of the upper surface 14 and a part of molten resin does not caused to foam in the center of the upper surface 14.

The door trim 1 formed in this way is mounted on a door panel of a vehicle door inside the vehicle compartment. During a vehicle collision, an object in the vehicle presses the armrest 12 formed on the door trim 1. In this case, the door trim 1 is broken and deformed in the recessed portion 15, so that the armrest 12 is crushed. This can absorb an impact resulting from the collision.

In the present illustrative aspect, the upper surface 14 of the armrest 12 extends in a thickness direction (opening direction of mold 2) of the flat portion 11. Accordingly, even though the recessed portion 15 is formed on the upper surface 14, no depression or the like will be formed on the upper surface 14. The reason is that, when the pair of molds 2, 3 are opened, molten resin exists sufficiently in other portions except the recessed portion 15 to foam a sufficient amount of molten resin.

In the present illustrative aspect, no depression or the like will be formed on a decorative surface of the door trim 1, and a door trim 1 with good appearance can be manufactured. A thickness direction of the upper surface 14 of the armrest 12 is different from an opening direction of the mold 2 (movable mold). Accordingly, even after the foaming of a molten resin, the thickness of the upper surface 14 of the armrest 12 hardly changes, which will form no depression or the like on the upper surface 14 of the armrest 12.

During a vehicle collision, the armrest 12 is pressed by an object in a vehicle. This causes the armrest 12 to be deformed and crushed in the recessed portion 15. Accordingly, the door trim 1 according to the present illustrative aspect can mitigate damage to the object during a vehicle collision without particularly changing the shape of the armrest 12.

(Second Illustrative Aspect)

Referring to FIGS. 4-5, the second illustrative aspect according to the present invention will be described blow. The left side of a door trim 4 shown in FIG. 5 is the interior side of a vehicle compartment and a surface inside the vehicle compartment is a decorative surface.

As shown in FIG. 4, a pair of molds 5, 6 are disposed so as to face each other horizontally. Between the pair of molds 5, 6, a cavity CV2 is formed. The one mold 5 is a movable mold and forms a decorative surface of the door trim 4 (a surface inside the vehicle compartment), while the other mold 6 is a stationary mold and forms a surface of the door trim 4 facing outward from the vehicle compartment.

In the same way as for the first illustrative aspect, a pair of molds 5, 6 have opposing surfaces 51, 61 for forming a flat portion 41, horizontal surfaces 52, 62 for forming an upper surface 44 of an armrest 42 and vertical surfaces 53, 63 for forming a front surface 43 of the armrest 42, respectively. The vertical surfaces 53, 63 extend obliquely downward from ends of the horizontal surfaces 52, 62.

In the present illustrative aspect, a protrusion portion 64 is formed substantially at a central portion of the horizontal surface 62 of the mold 6 (stationary type) in the lengthwise direction. A cross section of the protrusion portion 64 is formed into a substantially triangular shape. The protrusion portion 64 is formed on the horizontal surface 62 in the same way as for the first illustrative aspect 1 and extends in a front/reverse direction of paper in FIG. 4.

The door trim 4 can be produced in the following processes: First, molten resin material such as polypropylene added with foaming agent is injected and supplied into the cavity CV2 formed between the pair of molds 5, 6. At a predetermined period after the molten resin material is supplied into the cavity CV2, the one mold 5 (movable mold) is moved away from the other mold 6 (stationary mold) (core-back of the mold 5). This allows the pair of molds 5, 6 to open, by a predetermined amount, in a thickness direction of the flat portion 41 (a direction indicated by an arrow in FIG. 4). Then, as shown in FIG. 5, an internal pressure of the cavity CV2 lowers to foam the molten resin material with which the cavity CV2 is filled, thus forming the door trim 4.

As shown in FIG. 5, the foamed molten resin material is formed to have a predetermined thickness by the opposing surfaces 51, 61 and the vertical surfaces 53, 63 of the pair of molds 5, 6. This forms the flat portion 41 and the front surface 43 of the armrest 42.

As shown in FIG. 5, the upper surface 44 of the armrest 42 is formed by the horizontal surfaces 52, 62 of the pair of molds 5, 6. In other words, the upper surface 44 of the armrest 42 is formed by a region sandwiched by the horizontal surfaces 52, 62 in the pair of molds 5, 6.

Substantially in the center of the upper surface 44 of the armrest 42, there is formed a notched groove 45 recessed upward. The notched groove 45 corresponds to a recessed portion in the present invention. The recessed portion 45 is formed by the protrusion portion 64 provided on the stationary mold 6. The notched groove 45 is formed in a surface of the door trim 4 facing outward from the vehicle compartment. The bottom of the notched groove 45 is a thin-wall portion in which part of the door trim 4 is formed into a thin-wall shape.

On other configurations, descriptions thereof are omitted because of the similarities to the first illustrative aspect. According to the door trim 4 of the present illustrative aspect, the notched groove 45 is formed at a central portion of the upper surface 44 in a width direction. The upper surface 44 of the armrest 42 extends long in a thickness direction of the flat portion 41. Accordingly, even though the notched groove 45 is formed in the upper surface 44, molten resin can be foamed sufficiently because other portions except the notched groove 45 have a sufficient amount of molten resin. Accordingly, this enables manufacture of the door trim 4 with good appearance without forming a depression or the like on a decorative surface of the door trim 4.

(Other Illustrative Aspects)

The present invention is not limited to foregoing descriptions and illustrative aspects described referring to drawings. For example, the following illustrative aspects are included as well in the technical scope of the present invention and further in addition to the following, various changes and implementations may be made without departing from the spirit and the scope of the present invention:

(1) The upper surface (vertical wall portion) of an armrest is not required to extend in such a direction as to completely meet a thickness direction of a flat portion. If an amount of molten resin material to be foamed is sufficient, the upper surface of the armrest may extend in a different direction from the thickness direction of the flat portion.

(2) The opening direction of a pair of molds is not required to completely meet the thickness direction of the flat portion. For example, as shown in the second illustrative aspect, there may be used a pair of molds which open in a little different direction from the thickness direction of the flat portion.

(3) The recessed portion (thin-wall portion) may have any shape, provided that the door trim can be deformed if pressed during a vehicle collision.

(4) The recessed portion (thin-wall portion) is not required to be formed on an upper surface of an armrest. For example, the recessed portion may be formed in a peripheral edge portion of a door trim. Otherwise, the recessed portion may be formed at a flange portion or the like extending in an opening direction of a mold.

(5) In forming the recessed portion in an upper surface of an armrest, the armrest is formed at a position in a width direction where no depression or the like is formed on a decorative surface. Specifically, an armrest may be formed at any position in a width direction inside the vehicle compartment, provided that an inequality of a/A≧a′/A′ is satisfied, where A is a thickness of the flat portion (main-body portion) of a door trim before core-back, a is a thickness of the flat portion (main-body portion) of the door trim after core-back, A′ is a thickness of an upper surface (vertical wall portion) of an armrest before core-back and a′ is a thickness of the upper surface (vertical wall portion) of the armrest after core-back.

(6) The recessed portion (thin-wall portion) is not required to continuously extend in a lengthwise direction (vehicle longitudinal direction) of the armrest. For example, the recessed portion may be formed at part of the armrest in the lengthwise direction, or may be formed at the armrest by dividing it into multiple portions in the lengthwise direction.

(7) The above-described illustrative aspects show aspects where the present invention is applied to a vehicle door trim, but the present invention may be applied to other automotive interior materials such as a vehicle quarter panel and a pillar garnish.

Claims

1. A method of manufacturing automotive interior material,

the automotive interior material being mounted on a vehicle body inside the vehicle compartment and having a recessed portion of a thin-wall shape in cross section on a surface facing outward from the vehicle compartment,

the automotive interior material being pressed by an object in a vehicle and deformed by the recessed portion so as to absorb an impact during a vehicle collision and

the automotive interior material including a main body covering the vehicle body and a vertical wall portion connected to the main body and extending in a thickness direction of the main-body portion,

the method comprising the steps of:

providing a protrusion portion on a portion that forms the vertical wall portion of a mold and supplying molten resin material added with foaming agent into the mold;

opening the mold by a predetermined amount in a main-body thickness direction after supplying the molten resin material into the mold to foam the molten resin material and to form the main body with a predetermined thickness; and

forming the recessed portion for the vertical wall portion by the protrusion portion.

2. The method of manufacturing automotive interior material according to claim 1, wherein the automotive interior material is a door trim mounted on a vehicle door panel.

3. An automotive interior material manufactured using the method of manufacturing automotive interior material according to claim 1.

4. The automotive interior material according to claim 3, wherein the automotive interior material is a door trim mounted on a vehicle door panel.

5. The automotive interior material according to claim 4, wherein the vertical wall portion constitutes an upper surface of an armrest of the door trim.