JPH0597007A - Structure of bumper reinforcement with closed section - Google Patents

Abstract

PURPOSE:To maintain the condition where the load in the colliding direction is absorbed effectively and increase the strength by restricting swings of the foremost of a horizontal rib with a swing checking part, and suppressing deformation in the runoff direction at the time of collision. CONSTITUTION:An inner member 3 and outer member 2 having channel-shaped section split to the fore and aft at the time of installing in a car are joined together by a die slide forming method, and a bumper reinforcement is formed in a closed section, and therein the outer member 2 is provided with horizontal ribs 7 in the form of flat plate extending within this closed section in the direction of die opening while the inner member 3 is furnished with swing checking parts 9 which are engaged by the foremost of the horizontal ribs 7 and check swinging. This allows maintaining high producibility by the die slide shaping method and eliminates necessity for reinforcement through installing a metal plate alongside with the aid of the horizontal ribs 7, which leads to accomplishment of lightweight construction and cost-down.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a closed-section bumper reinforcement structure in which two parts made of synthetic resin are joined to each other by a die slide molding method.

[0002]

2. Description of the Related Art Conventionally, for example, JP-A-2-26704.
A bumper having a structure as disclosed in Japanese Patent No. 7 is mounted on a vehicle. As shown in FIG. 8, the bumper is formed by interposing a foam material 53 between a skin member 51 and a bumper reinforcement 52 which is a strength member. Bumper reinforcement 52
Has a closed cross-section structure including an inner member 55 attached to a stay 54 extending from the vehicle body, and an outer member 56 having a U-shaped cross-section and having a peripheral edge joined to the inner member 55 so as to face the stay 54 in the front-rear direction of the vehicle.

The above bumper reinforcement 52
Is made of a hard synthetic resin, and is manufactured through the steps of manufacturing the inner member 55 and the outer member 56 and then bonding the peripheral edges. In this case, the inner member 55 and the outer member 56 are manufactured. Therefore, a separate manufacturing apparatus is required, and further, a transfer operation to the apparatus for bonding is required, and sufficient productivity cannot be obtained.

On the other hand, as a manufacturing method capable of improving the productivity of a synthetic resin product having a closed cross-section structure as described above, for example, Japanese Patent Publication No. 2-38377 discloses a die slide molding method (die slide injection method, Hereinafter, the DSI method) has been proposed. As shown in FIG. 9, the manufacturing apparatus is provided with a fixed die 61, a slide die 63 that is moved up and down by a cylinder 62, and a movable die 64 that is moved in the contact direction with respect to the slide die 63. Has been. A primary injection sprue 66 communicating with a main sprue 65 formed on the fixed die 61 is provided at substantially the center of the slide die 63.
Is formed, and cavities 67 and 68 corresponding to the shape obtained by dividing the final molded body into two parts are provided at upper and lower positions with the primary injection sprue 66 sandwiched between the mating surfaces of the slide mold 63 and the movable mold 64. ing. Further, a sprue 69 for joining is provided on the lower side of the slide die 63.

When the molten resin is injected from the injection molding machine into the main sprue 65 in the primary injection mold clamped state shown in FIG. 9, the resin is injected into the primary injection sprue as shown in FIG. 66, runner 70, gate 71
・ After 71, both cavities 67 and 68 are simultaneously filled. When this resin is solidified, split semi-finished products 72, 72 are formed in both cavities 67, 68.

Thereafter, as shown in FIG.
Is opened from the slide mold 63, and the resin 73 solidified in the primary injection sprue 66 is removed. Next, as shown in FIG. 12A, after sliding the slide die 63 upward, the movable die 64 is moved and the die is clamped. At this time, the two semi-finished products 72 are positioned so as to abut each other, and the sprue 69 for joining is communicated with the main sprue 65. The shapes of the cavities 67 and 68 are set so that the joint resin filled space 74 is formed on the outer peripheral side of the abutting surfaces of the semi-finished products 72 and 72 in the secondary injection mold clamping state. Therefore, after that, as shown in FIG.
When the molten resin is injected again through the main sprue 65, the resin is filled in the joining resin filling space 74 through the joining sprue 69 and the runner 70. By solidifying the injected resin, both semi-finished products 72, 72 are welded to each other on the outer peripheral side thereof, and a resin molded product having a closed cross-section structure is obtained as shown in FIG.

The manufacturing method by the DSI method as described above is
By providing a molding die in which the cavities 67 and 68 at the time of primary injection molding correspond to the shapes of the inner member 55 and the outer member 56, it is possible to apply to the manufacture of the bumper reinforcement 52 as well. This enables efficient production.

[0008]

However, although the bumper reinforcement can be manufactured efficiently by the DSI method as described above, the conventional bumper reinforcement structure is not always sufficient. There is a problem that satisfactory strength cannot be obtained. Therefore, as shown in FIG. 8 above,
For example, it is necessary to have a structure in which a metallic reinforcing plate 57 is arranged along the inner surface of the inner member 55,
In this case, there is a problem that the cost and weight cannot be reduced sufficiently.

The present invention has been made in view of the above-mentioned conventional problems, and its object is to maintain the high productivity on the premise that it is manufactured by the DSI molding method, and further improve the strength and It is an object to provide a structure of a bumper reinforcement having a closed cross section that can reduce weight and cost.

[0010]

In order to achieve the above-mentioned object, the structure of the closed-section bumper reinforcement of the present invention is divided in the front-rear direction at the time of assembly to a vehicle,
A structure of a closed cross-section bumper reinforcement in which at least one has an U-shaped cross section and an inner member and an outer member that are joined to each other by a mold slide molding method, and either one of the inner member and the outer member is provided. Is provided with a plate-shaped rib that extends in the mold opening direction in the closed cross section and reaches the vicinity of the other member, and the other member engages with the tip end of the rib and the tip end side It is characterized in that a deterrent unit for deterring the shake of the is provided.

[0011]

According to the above construction, since the plate-shaped ribs in the closed cross section are provided in a shape extending in the mold opening direction, it is possible to manufacture even with such a structure by the mold slide molding method. Yes, and thus high productivity is maintained. Further, since the ribs for improving the strength are provided as described above, it is not necessary to additionally attach and reinforce the metal plate as in the conventional case, and therefore it is possible to reduce the weight and reduce the cost. .. Moreover, since the ribs are provided in the front-rear direction of the vehicle, that is, parallel to the collision load direction, and the deflection of the tip portion is regulated by the restraint portion, bumper reinforcement at the time of collision With respect to the deformation in the front-back direction, the tip side of the rib does not escape from the collision direction and is inclined and deformed, and a state in which the load in the collision direction is effectively absorbed is maintained. As a result, the strength can be further improved.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe one embodiment of the present invention with reference to FIGS.

As shown in FIG. 1, a bumper reinforcement 1 according to this embodiment includes an outer member 2 and an inner member 3 which are joined to each other so as to face each other in the front-rear direction of the vehicle (left-right direction in the drawing). It consists of Both of these members 2 and 3 are made of hard synthetic resin. The inner member 3 located on the vehicle body side (right side in the drawing) is formed in a substantially flat plate shape, and is fixed to a stay (not shown) extending from the vehicle body in a substantially vertical mounting state. The outer member 2 has a substantially U-shaped outer peripheral cross-sectional shape, and the tip ends of the horizontal outer wall surfaces 2a and 2b extending toward the vehicle body, that is, the upper portion and the lower portion, are joined to the upper and lower ends of the inner member 3, respectively. .. In this way, on the front side of the bumper reinforcement 1 constituted by joining the outer member 2 and the inner member 3 to each other so as to form a closed cross-sectional shape, the impact absorbing member 4 made of foamed resin or the like is interposed. Then, the bumper 6 is formed by applying the skin member 5 made of a relatively soft synthetic resin.

Inside the bumper reinforcement 1, flat horizontal ribs 7 and vertical ribs 8 are respectively formed.
Are provided on the outer member 2. Horizontal rib 7
In the present embodiment, 7 is provided at a position that divides the internal space into approximately three equal parts in the height direction, and has a projecting structure from the vertical outer wall surface 2c of the outer member 2, and the tip end portion of the inner member 3 is provided. As it reaches the vicinity of the inner surface, as shown in FIG.

As shown in FIG. 3, a plurality of vertical ribs 8 are provided at appropriate intervals in the width direction, and as shown in FIG. 1, they extend from the vertical outer wall surface 2c of the outer member 2 toward the inner member 3. The upper and lower horizontal outer wall surfaces 2a and 2b and the horizontal ribs 7 and 7 of the outer member 2 within the range up to the midway position.
It is provided over the space.

On the other hand, on the inner surface of the inner member 3, there are provided shake preventing portions 9 and 9 having recessed grooves at height positions corresponding to the horizontal ribs 7 and 7, respectively. These shake suppressing portions 9 and 9 are respectively configured by providing short protruding pieces protruding toward the outer member 2 side by pair in the upper and lower positions with the recessed groove interposed therebetween. Then, the respective tip end portions of the horizontal ribs 7 extending from the vertical outer wall surface 2c of the outer member 2 to the inner member 3 side are fitted into the respective recessed grooves of the shake preventing portion 9, so that the horizontal ribs The deflection of the tip end side of 7.7 is regulated.

Note that FIG. 2 shows a cross-sectional structure of a joint region with the outer member 2 on the end side of the inner member 3. Each of the members 2 and 3 is provided with an outer-side joint portion 11 and an inner-side joint portion 12 having U-shaped cross sections facing each other in the front-rear direction. Outer side joint 11
Has a bifurcated shape of an outer protruding piece 11a and an inner protruding piece 11b which are parallel to each other, and an outer side recessed groove 11c is formed between these protruding pieces 11a and 11b. Further, the inner side joint portion 12 is provided with an outer side protruding piece 12a and an inner side protruding piece 12b protruding in parallel to the protruding pieces 11a and 11b, and an inner side recessed groove 12c is formed between these protruding pieces 12a and 12b. Has been formed.

The outer member 2 and the inner member 3 each having the above-mentioned joining portions 11 and 12 are joined to each other while the inner projecting piece 11b of the outer joining portion 11 is fitted in the inner recess groove 12c. Outer protrusion 12 of part 12
a is located in the outer side recessed groove 11c and is assembled with each other in an occlusal state. Then, the outer side recessed groove 11
In c, a space portion as the joint resin filling space 13 is formed between the outer protruding piece 12a of the inner side joint portion 12 and the outer protruding piece 11a of the outer side joint portion 11 located inside this. And this bonding resin filling space 1
As will be described later, the molten resin is injected into 3 and the molten resin is solidified, so that the joint portions 11 and 12 are joined to each other.

The bumper reinforcement 1 having the above structure is manufactured by the above-mentioned DSI method. In this case, as shown in FIG.
A slide die 23 that is vertically moved is provided between the movable die 22 and the movable die 22 that is movable in the contacting / separating direction (the horizontal direction in the drawing). A primary injection sprue 25, which communicates with the main sprue 24 formed on the fixed mold 21 when the slide mold 23 is in the primary injection state before sliding as shown in the figure, is formed at approximately the center of the slide mold 23. Has been done. The movable die 2 in the slide die 23
A male part 26 corresponding to the space shape between the horizontal ribs 7 and the vertical ribs 8 in the outer member 2 is provided on the upper surface of the primary injection sprue 25 on the mating surface with 2.

On the other hand, the movable die 22 is provided with a concave female die portion 27 surrounding the male die portion 26.
A space-shaped outer member cavity 28 corresponding to the outer member 2 is formed between the outer mold member 26 and the male mold portion 26. In addition, a space-shaped inner member cavity 29 corresponding to the inner member 3 is formed along the mating surface of the slide mold 23 and the movable mold 22 below the primary injection sprue 25. 23, a sprue 30 for joining is provided at a position lower than the cavity 29 for the inner member.

When the molten resin is injected from the nozzle 31 of the injection molding machine (not shown) into the main sprue 24 in the above-described primary injection state, the resin is moved from the primary injection sprue 25. The outer member cavity 28 and the inner member cavity 29 are filled with the runner 32 along the mating surface of the mold 22 and the slide mold 23 and the gates 33 and 34 provided above and below the runner 32, respectively. By solidifying, the outer member 2 and the inner member 3 are simultaneously formed.

Next, mold opening is performed to separate the movable mold 22 from the slide mold 23. At this time, the outer member 2 remains on the movable die 22 side, and the inner member 3 remains on the slide die 23 side. The solidified resin at the sprue runner gate used for the primary injection is cut off from the product and discarded outside the mold. Then, the slide mold 23 is lifted in the mold open state, and then the movable mold 22 is moved in the direction in which the movable mold 22 contacts the slide mold 23 and the mold is clamped.

At this time, as shown in FIG. 6, while the outer joint portion 11 and the inner joint portion 12 of the outer member 2 and the inner member 3 are overlapped with each other in the occlusal state described above over the entire circumference, they are fixed. The sprue 30 for joining of the slide mold 23 communicates with the main sprue 24 of 21, and
At the end of the runner 35 formed at the tip of the sprue 30 for joining, the outer member 2 and the inner member 3 are provided.
The joining resin filled space 13 in the joining region with the is communicated with.

Then, the operation of injecting the molten resin through the main sprue 24 is performed again, and as a result, the bonding resin filling space 13 is filled with the molten resin. Then, when the molten resin is solidified, the outer joint portion 1
1 and the inner side joint portion 12 are joined to each other over the entire circumference, and a bumper reinforcement 1 having a closed cross-sectional shape
Is created.

As described above, the bumper reinforcement 1 having the above structure can be manufactured by injection molding by the DSI method while maintaining high productivity. Further, since the horizontal ribs 7 and the vertical ribs 8 are provided inside the vehicle in the front-rear direction, that is, in parallel with the collision load direction, the strength against deformation is high, and as a result, the conventional bumper reinforcement described above is provided. As described above, it is not necessary to additionally install a metallic reinforcing plate or the like, and as a result, it is possible to further reduce the weight and reduce the cost.

Further, in the above-mentioned structure, particularly with respect to the horizontal rib 7 extending from the vertical outer wall surface 2c of the outer member 2 toward the inner member 3 side, the deflection of the tip portion of the horizontal rib 7 is caused by the deflection suppressing portion 9 provided in the inner member 3. It is regulated. As a result, even when the bumper reinforcement 1 is deformed in the front-rear direction at the time of a collision, the tip end side of the horizontal rib 7 does not escape from the collision direction and is inclined and deformed, so that the load in the collision direction is most effective. The state of absorption is maintained. This makes it even more rigid,
Energy absorption is improved.

In the structure of the above embodiment, the horizontal ribs 7 and the vertical ribs 8 are provided on the side of the outer member 2 having a U-shaped cross section. In this case, since the upper and lower horizontal outer wall surfaces 2a and 2b of the outer member 2 are located at the upper and lower ends of the vertical ribs 8, the upper and lower ends of the vertical rib 8 are integrally formed on these horizontal outer wall surfaces 2a and 2b. The configuration is linked. Therefore, the vertical rib 8 has a structure in which the vertical outer wall surface 2c and the upper and lower horizontal outer wall surfaces 2a and 2b are connected to each other on three sides, whereby the strength and rigidity are improved. In addition, since the restraint pieces for restraining the swing like the shake restraining portions 9 for the horizontal ribs 7 are not necessarily provided for the vertical ribs 8 connected to the outer peripheral wall surface on three sides as described above, the structure is simple. As a result, the weight can be further reduced and the mold can be easily manufactured.

In the above embodiment, the horizontal rib 7
Also, the example in which the vertical rib 8 is provided on the outer member 2 side has been described. In this case, when the mold is opened after the primary injection molding by the DSI method, the molded outer member 2 is moved to the movable mold 2.
The slide mold 23 should be left on the female mold part 27 side of
Since the male part 26 has a complicated shape that fills the lattice-shaped space between the horizontal ribs 7 and the vertical ribs 8, it tends to remain on the male part 26 side. Therefore, for example, it is necessary to provide the slide mold 23 with a knockout pin. Therefore, as shown in FIG. 7, for example, the horizontal ribs 7 and the vertical ribs 8 are provided in a shape extending from the inner member 3 side to the vertical outer wall surface 2c side of the outer member 2, and the shake suppressing portion 9 is provided on the vertical outer wall surface. It is also possible to adopt a configuration provided in 2c. In this configuration,
The upper and lower horizontal outer wall surfaces 2a and 2b of the outer member 2 are provided with projecting pieces 36 and 36, and the upper and lower ends of the vertical ribs 8 are fitted into the grooves of the pieces 36 and 36, respectively. The deflection of the upper and lower ends of the vertical rib 8 is regulated.

Further, in the above embodiment, both the horizontal ribs 7 and the vertical ribs 8 are provided in the bumper reinforcement 1, but it is possible to provide only one of them.
Furthermore, if it is a plate shape that extends in the front-rear direction, it may have other configurations such as being provided so as to be inclined with respect to the width direction.

[0030]

As described above, the structure of the bumper reinforcement having a closed cross section according to the present invention is configured such that one of the inner member and the outer member extends in the mold opening direction within the closed cross section and the other member. Is provided with a plate-shaped rib extending to the vicinity of, and the other member is provided with a restraining portion that engages with the tip portion of the rib and restrains the shake on the tip portion side.

As a result, it is possible to manufacture by a die slide molding method, high productivity is maintained, and
Since the ribs for improving the strength are provided inside, there is no need to additionally install a metal plate or the like for reinforcement as in the conventional case, and therefore, it is possible to reduce the weight and reduce the cost. Moreover, the ribs are provided in the front-rear direction of the vehicle, that is, parallel to the collision load direction, and
Since the deflection of the tip part is regulated by the restraint part, the tip side of the rib does not escape from the collision direction and is inclined and deformed against deformation in the front-back direction of the bumper reinforcement at the time of collision. , The state of effectively absorbing the load in the collision direction is maintained. Thereby, there is an effect that the strength can be further improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a bumper reinforcement according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a joint region between an outer member and an inner member in the bumper reinforcement.

FIG. 3 is a plan view of the bumper reinforcement.

FIG. 4 is a front view of the bumper reinforcement.

FIG. 5 is a schematic cross-sectional view of a molding die when the bumper reinforcement is molded by a DSI molding method.

FIG. 6 is a schematic cross-sectional view of a molding die showing secondary injection molding in the molding process by the DSI molding method.

FIG. 7 is a sectional view of a bumper reinforcement according to another embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a conventional bumper reinforcement.

FIG. 9 is a schematic cross-sectional view showing the configuration of a molding apparatus adopting the DSI molding method.

FIG. 10 is a cross-sectional view of an essential part showing a primary injection molding process in the molding apparatus.

FIG. 11 is a main-portion cross-sectional view showing a mold opening step after primary injection molding in the molding apparatus.

12A and 12B show a molding process in the molding apparatus, wherein FIG. 12A is a sectional view of a main part showing a state where mold clamping for secondary injection molding is performed, and FIG. It is a principal part sectional view which shows a secondary injection molding process.

FIG. 13 is a cross-sectional view of a resin product obtained by molding with the molding device.

[Explanation of symbols]

 1 Bumper reinforcement 2 Outer member 3 Inner member 7 Horizontal ribs 8 Vertical ribs 9 Shake prevention part

Front page continuation (72) Inventor Naoshi Kiyama 1 175, Ojihara, Hachimotomatsu-cho, Higashihiroshima City, Hiroshima Prefecture Daikyo Co., Ltd. (72) Inventor Shozo Nishida 1-6-7 Funakoshi-minami, Aki-ku, Hiroshima-shi, Hiroshima Japan Steel Works Hiroshima Works

Claims (1)

[Claims] 1. A bumper having a closed cross section formed by joining an inner member and an outer member, which are divided in the front-rear direction when assembled to a vehicle, and at least one of which has a U-shaped cross section, by a die slide molding method. In the reinforcement structure, one of the inner member and the outer member is provided with a plate-shaped rib extending in the mold opening direction within the closed cross section and reaching the vicinity of the other member, and A structure of a closed-section bumper reinforcement characterized in that the other member is provided with a restraining portion that engages with the leading end of the rib to restrain the swinging on the leading end side.