JP2010030491A - Absorber for bumper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an absorber for a bumper reducing any dispersion of the shock absorbing performance. <P>SOLUTION: The absorber 10 for bumper comprises: a first energy absorbing part 30 formed by foaming a resin forming material; a second energy absorbing part 40 formed of a resin forming material; and a bridging part 50 which is formed by foaming a resin forming material, and arranged facing the inner-vehicle side of a bumper fascia 80 to fix the first and second energy absorbing parts 30, 40 to each other. The second energy absorbing part 40 has a thin walled part 41 along the longitudinal direction D2 of the bumper fascia 80 on a boundary part 51 between a deformation permitting space SP1 and the bridging part 50, and has a slit 42 extending from the bumper reinforcement 70 side to the bumper fascia 80 and connected to the thin-walled part 41. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a bumper absorber provided between a bumper reinforcement and a bumper fascia in an automobile.

  Before and after the automobile, a bumper provided with an impact absorbing function is provided in order to protect the vehicle body and to reduce the load applied to the legs of the pedestrian in the event of an interpersonal accident. The bumper absorber is provided between the bumper reinforcement and the bumper fascia.

  In Patent Documents 1 and 2, collision energy of a bumper for a vehicle including a compression energy absorbing material, a buckling energy absorbing material made of a plate-like member, and a plurality of columnar connecting members arranged at intervals from each other. An absorber is described. In paragraph 0012 of Patent Document 1, at the position where the connecting member is provided, the compressive energy absorbing material is hardly compressed and deformed by the thickness of the connecting member with respect to the longitudinal direction of the vehicle body, but an obstacle exists between the connecting members. Since there is nothing, it is described that the collision energy can be effectively absorbed by compressing and deforming the substantially entire width of the compression energy absorbing material in the longitudinal direction of the vehicle body. That is, it is essential to provide a plurality of columnar connecting members, and it is essential to leave a space between the connecting members.

  Patent Document 3 discloses a compression energy absorbing material, a buckling energy absorbing material made of a plate-like member, and a front fixed holding that is provided on the inner surface of the bumper fascia so as to hold the front end portions of both energy absorbing materials. And an impact energy absorbing device for a vehicular bumper. The front fixed holding member is integrally formed with the bumper fascia. That is, when the collision energy absorbing device is viewed from the front side except for the bumper fascia, a large opening is formed between the compression energy absorbing material and the buckling energy absorbing material.

Patent Document 4 describes a bumper absorber that aims to reduce the impact on impact absorption performance due to the direction of the collision surface of a collision object colliding with the bumper fascia without complicating the structure of the bumper fascia. Has been. The bumper absorber is disposed so as to face the inside of the bumper fascia with the first energy absorbing portion formed by foaming the resin molding material, the second energy absorbing portion formed of the resin molding material And a bridge part. The second energy absorbing portion extends from the bumper reinforcement toward the bumper fascia at a position where a space allowing buckling is formed between the second energy absorbing portion and the first energy absorbing portion on the bumper reinforcement side. Yes. The bridging portion covers the first energy absorbing portion and the second energy absorbing portion while closing an opening between the first energy absorbing portion and the second energy absorbing portion on the bumper fascia side. They are fixed to each other.
JP 2004-345423 A JP 2004-345425 A JP 2004-345424 A JP 2007-326481 A

  The bumper absorber described above may cause variations in shock absorption performance. In the collision energy absorbing device described in Patent Documents 1 to 3, when the collision energy absorbing device is viewed from the front side except for the bumper fascia, a large opening is formed between the compression energy absorbing material and the buckling energy absorbing material. Therefore, it is assumed that variation in shock absorption performance occurs.

  In view of the above, an object of the present invention is to provide a bumper absorber capable of reducing variation in shock absorbing performance.

  In order to achieve the above object, the present invention is a bumper absorber provided between a bumper reinforcement and a bumper fascia outside the bumper reinforcement in an automobile, and is formed by foaming a resin molding material. A first energy absorbing portion provided along the longitudinal direction of the bumper fascia and extending from the bumper reinforcement toward the bumper fascia, and formed of a resin molding material, along the longitudinal direction of the bumper fascia Provided at a position where a space allowing deformation of itself is formed between the bumper reinforcement and the first energy absorbing portion on the bumper reinforcement side, and extending from the bumper reinforcement toward the bumper fascia. Formed by foaming a resin molding material and a second energy absorbing portion; The first energy absorption part and the second energy absorption part are arranged facing the vehicle interior side of the isia, and include a bridge part that fixes the first energy absorption part and the second energy absorption part to each other. A thin wall portion is formed along the longitudinal direction of the bumper fascia at the boundary portion between the bumper fascia and the bridge portion, and a slit extending from the bumper reinforcement side toward the bumper fascia and connected to the thin wall portion is formed. It is characterized by being.

That is, a space in which the second energy absorbing portion is not restrained is formed between the first energy absorbing portion formed by foaming the resin molding material and the second energy absorbing portion formed of the resin molding material. Therefore, the deformation of the second energy absorbing portion is not hindered during impact input. Then, when an impact force is input, the reaction force increases as the displacement increases in the first energy absorption unit, whereas the reaction force increases rapidly and increases at the initial stage in the second energy absorption unit. And then the reaction force decreases rapidly. As a result, the reaction force against the impacted object becomes a reaction force that combines the first and second (first and second) energy absorbing parts, and the impacted object has a substantially constant reaction over a long period of the displacement of the absorber. Power will act. Therefore, it is possible to appropriately absorb the collision energy over a long period of displacement of the absorber, and good shock absorption performance can be obtained.
In addition, since the bridging portion formed by foaming the resin molding material is arranged facing the inside of the bumper fascia and fixes both energy absorbing portions to each other, the collision object that collided with the bumper fascia Even if the collision surface is not perpendicular to the direction connecting the bumper reinforcement and the bumper fascia, the input load can be received on the wide surface of the second energy absorbing portion, and there are the first and second energy absorbing portions. Phenomenon that falls only in the direction can be suppressed.

  Furthermore, since the thin wall portion of the second energy absorbing portion is formed along the longitudinal direction of the bumper fascia at the boundary portion between the space and the bridge portion, the second energy absorbing portion is the boundary at the time of impact input. It becomes easy to bend from the part. Also, the slit of the second energy absorbing portion extends from the bumper reinforcement side toward the bumper fascia and is connected to the thin wall portion. Even at this point, the second energy absorbing portion starts from the boundary portion at the time of impact input. As it becomes easy to bend. And the dispersion | variation in shock absorption performance can be reduced effectively by forming the said thin part and the said slit simultaneously in a 2nd energy absorption part.

The position where the bumper absorber is provided may be the front part of the automobile, the rear part of the automobile, the side part of the automobile, and the like. The bumper fascia may be provided in a direction shifted from a horizontal direction when viewed from the bumper reinforcement.
The resin molding material may be a molding material containing a resin, and may be a material made only of a resin, or a material containing a material other than a resin such as an additive.
The extending direction of the first and second energy absorbing portions may be a direction shifted from the horizontal direction. The first energy absorber may or may not contact the bumper fascia. The second energy absorbing unit may or may not contact the bumper fascia.

According to the first aspect of the present invention, it is possible to reduce the variation in shock absorbing performance.
In the inventions according to claims 2 and 5, the variation in the shock absorbing performance can be further reduced.
In the inventions according to claims 3 and 4, it is possible to reduce the influence on the impact absorbing performance due to the direction of the collision surface of the colliding object colliding with the bumper fascia.

(1) Configuration of bumper absorber:
FIG. 1 is an exploded perspective view showing a main part of a passenger car 1 employing a bumper absorber 10 according to an embodiment of the present invention. FIG. 2 is a perspective view showing the absorber 10 as viewed from the front side. 3 and 4 are perspective views showing the B1 portion of the absorber 10 shown in FIG. 2, FIGS. 5 and 9 are views showing the second energy absorbing portion 40, and FIG. 6 is a diagram showing the absorber 10 shown in FIG. FIG. 7 is a vertical sectional view showing the absorber 10 shown in FIG. 2 in a sectional view at the position A2-A2 in FIG. 3, and FIG. 8 is a first sectional view shown in FIG. FIG. 10 is an exploded perspective view schematically showing a state in which the absorber 10 is manufactured, and FIG. 11 is a bumper for an automobile, showing an area ratio for closing the opening between the first and second energy absorbing portions 30 and 40. It is a figure which shows a mode that it assembled | attached to 100 with a vertical cross section.
In FIG. 1, the bumper 100 is shown in an exploded manner at the front portion of the passenger car 1. The bumper absorber according to the present invention can be applied to the rear and side bumpers of an automobile, but will be described by taking the absorber 10 at the front of the automobile as an example.
The front bumper 100 includes a bumper reinforcement 70 that is attached and fixed to the front side of the vehicle body of the automobile, and a bumper fascia 80 that is provided on the front side (vehicle outer side) of the reinforcement 70 and covers the reinforcement 70 and the absorber 10. In order to absorb the impact, a bumper absorber 10 provided between the reinforcement 70 and the bumper fascia 80 is provided. Of course, bumpers provided with parts other than these parts 10, 70 and 80 are also included in the present invention.

  The bumper reinforcement 70 has a length close to the width of the automobile, and is disposed with the longitudinal direction directed in the vehicle width direction D2, for example, the front ends of a pair of left and right front side frames extending in the front-rear direction D1 at the front portion of the vehicle body. It is connected and fixed to the part. The reinforcement 70 has an outer shape elongated in the vehicle width direction, and is formed in a substantially rectangular parallelepiped shape such as a straight rectangular parallelepiped shape or a curved rectangular parallelepiped shape. For example, the reinforcement member 70 extrudes a metal member such as a steel plate into a cylindrical shape having a rectangular cross section. It is formed into a long shape by molding or the like. As shown in FIG. 11, the reinforcement 70 is formed in a cylindrical shape having a plurality of plate-like partition walls 72 extending in the front-rear direction for reinforcement. Of course, various structures are conceivable for the reinforcement, and in order to protect the vehicle body in the event of a collision accident or the like, it is assumed that the required strength and shock absorption are obtained. In addition, the reinforcement has a role of absorbing a shock by being crushed by itself, and also has a function as a pedestal for a shock absorber function to be crushed by a bumper absorber.

The bumper fascia 80 has the length of the width of the automobile, is disposed with the longitudinal direction thereof directed in the vehicle width direction D2, and is attached and fixed to the front portion of the vehicle body. The bumper fascia 80 is formed into a thin plate by molding a resin molding material having a synthetic resin such as a thermoplastic resin or a thermosetting resin by press molding, injection molding, or the like in order to reduce the weight of the automobile. The bumper fascia 80 covers the reinforcement 70 and the absorber 10 when viewed from the outside of the automobile, and a design suitable for constituting the front surface of the automobile is given to the outer surface. The bumper fascia 80 also has a function of blocking external heat and rain wind from entering the inside of the vehicle so as to prevent the impact absorption performance of the reinforcement 70 and the absorber 10 from being deteriorated. The bumper fascia may be provided with a vent called a grill for the purpose of introducing air into the radiator.
The bumper fascia 80 is formed in a thin shape with a resin molding material having a resin. Therefore, when an impact is input, the bumper fascia 80 is deformed with a relatively small load. The input impact energy is absorbed mainly by the absorber 10 and is absorbed by the reinforcement 70 when it is not absorbed by the absorber.

The bumper absorber 10 is provided to protect a pedestrian in the event of a personal accident, and when a collision object such as a pedestrian's leg collides with the front surface of the bumper fascia (vehicle outer surface 80a) from the direction of the bumper fascia. It has a function of receiving an impact, deforming between the collision object and the bumper reinforcement, absorbing the energy of the collision, and reducing the reaction force to the collision object.
The bumper absorber can be filled with foamed resin particles in a mold, heated and fused to each other, or blown with air into a parison in which the resin is melted into a cylinder. For example, a blow molded body (a kind of resin molded body) molded into a resin, a resin injection molded body (a kind of resin molded body) formed by injection molding a resin into a required shape, and the like are used. The bumper absorber of the present invention has a structure excellent in shock absorption by combining a resin foam molded body and a resin molded body.

The bumper absorber 10 includes a soft leg (first energy absorption part) 30 formed by foaming a resin molding material, a hard leg (second energy absorption part) 40 formed of a resin molding material, and a resin. And a bridge portion 50 formed by foaming a molding material. The soft legs 30 are provided along the longitudinal direction D <b> 2 of the bumper fascia and extend from the reinforcement 70 toward the bumper fascia 80. The hard leg 40 is provided along the longitudinal direction D2 of the bumper fascia, and the reinforcement is formed at a position where a space (deformation allowable space SP1) that allows bending deformation is formed between the soft leg 30 and the reinforcement 70 side. It extends from 70 toward bumper fascia 80. The bridge portion 50 is disposed facing the vehicle inner side of the bumper fascia 80, and fixes the soft leg 30 and the hard leg 40 to each other while sandwiching the edge (front edge portion 40c) of the hard leg 40 on the bumper fascia 80 side. is doing. Here, the bridge portion 50 closes the opening OP1 between the soft leg 30 and the hard leg 40 on the bumper fascia 80 side so that the area ratio is half or less.
The longer the bumper absorber is in the front-rear direction, the greater the amount of shock energy absorbed, but the longer the vehicle is in the front-rear direction. Therefore, the bumper absorber is required to be as short as possible in the front-rear direction so as to be able to absorb the required energy without applying an excessive reaction force to the collision object.

FIG. 12 shows the compression load (reaction force) F with respect to the displacement x of the resin foam molded body, the extended resin molded body, and the combination of these in a graph format. Here, in a range where the compression load F does not become excessive, if the compression load F increases quickly in a region where the displacement x is small and then the compression load F becomes substantially constant with a long displacement, an excessive reaction force is exerted on the collision object. It is possible to absorb a lot of impact energy without giving any. If it has such an x-F characteristic, it can be said that the shock absorbing performance of the absorber is very good.
In addition, the measurement of the compressive load F with respect to the displacement x can be performed as follows, for example.
First, an absorber sample that collides with an impactor having a predetermined shape is attached to a fixed base at a predetermined position. The impactor is configured to move horizontally at a constant speed (for example, 40 km / h) toward the fixed base. The impactor has a built-in load sensor for measuring the compressive load F, and the control device (not shown) can detect the compressive load F according to the movement position of the impactor. The displacement x of the absorber indicates the moving distance from the position where the impactor contacts the absorber sample.
Then, by causing the impactor to collide with the absorber sample from the front under the above conditions, the compressive load F with respect to the displacement x of the absorber sample can be measured.

A resin foam molded body such as a soft leg has an x-F characteristic in which the compression load F1 increases as the displacement x of the resin foam molded body increases. With only the resin foam molded article, the amount of impact energy absorbed is reduced by the slow rise of the compression load at the initial stage of displacement. On the other hand, when the compressive force is applied in the extending direction, the x-F characteristic of the resin molded body such as a hard leg rapidly peaks at the initial stage when the compressive force is applied. After that, the compression load F2 has a characteristic of rapidly decreasing. Therefore, in the resin molded body, the amount of impact energy absorbed is reduced by the smaller compression load at the later stage of displacement.
The compression load F3 of the absorber is a compression load F1 + F2 that is a combination of the compression load F1 of the resin foam molding and the compression load F2 of the resin molding, and becomes a substantially constant compression load over a long period of displacement. As a result, the reaction force against the impacted object becomes a substantially constant reaction force that combines the reaction force from the resin foam molding and the reaction force from the resin molding, and is excessive in the initial stage after the impact occurs. The reaction force quickly increases within a range that does not become, and then becomes substantially constant with a long displacement.

The absorber 10 is substantially the same as the reinforcement 70, has a length close to the width of the automobile, has an outer shape elongated in the vehicle width direction, and is a straight, substantially rectangular parallelepiped shape having a groove formed on the reinforcement 70 side. Or a curved, substantially rectangular parallelepiped shape. In the absorber 10 of the present embodiment, an impact receiving surface that receives an impact is formed on the front side facing the bumper fascia 80, and the soft leg 30 and the hard leg 40 are vertically moved from the impact receiving surface toward the reinforcement 70. D3 is alternately provided at predetermined positions at positions adjacent to each other.
The length L0 (L1 + L2 in FIG. 6) of the absorber 10 in the front-rear direction D1 is set according to the vehicle type, and is, for example, 30 to 150 mm. Moreover, although the length H1 of the up-down direction of the absorber 10 is set according to a vehicle model, it is set to 20-150 mm, for example. Here, when H1> L0, it is presumed that the soft leg and the hard leg are less likely to fall in the same direction at the time of impact input, and the impact absorbing performance is improved.

  Here, the soft leg 30 is formed by foaming a resin and forming a plate shape that is thicker up and down than the hard leg 40. The rear edge 30d is a surface facing the bumper fascia 80 in the reinforcement 70 (the vehicle outer side surface 70a). ), Extending forward from the reinforcement 70 side toward the bumper fascia 80, the front edge portion 30c is in contact with the rear surface (inside surface 80b) of the bumper fascia, and the upper surface 30a and the lower surface 30b are horizontal. Has been placed. In addition, a plurality of soft legs 30 are provided from the bridge portion 50 toward the reinforcement 70 so as to form the groove-shaped thinned portion 20 on the reinforcement 70 side. The thinned portion 20 is formed in a groove shape that is recessed from the reinforcement side to the bumper fascia side, and is arranged with the longitudinal direction directed in the vehicle width direction D2 to be a space SP1 that allows bending deformation of the hard leg 40. Yes. In the present embodiment, a plurality of thinned portions 20 are formed on the rear surface of the absorber 10, and each thinned portion has a shape cut out in a U-shaped cross section.

The hard leg 40 is formed by forming a thin plate shape vertically below the soft leg 30 without foaming the resin, and the rear edge portion 40d is a surface facing the bumper fascia 80 in the reinforcement 70 (the vehicle outer surface 70a). They are in contact with each other and extend forward from the reinforcement 70 side toward the bumper fascia 80 so that the front edge portion 40c contacts the rear surface of the bumper fascia (the vehicle interior side surface 80b), and the upper surface 40a and the lower surface 40b are disposed horizontally. ing. Further, the hard leg 40 extends horizontally into the thinned portion 20 at a position where a space SP1 allowing its own bending deformation is formed from the bridge portion 50 toward the reinforcement 70. In the present embodiment, a plurality of hard legs are provided, and each hard leg is sandwiched between a pair of soft legs in the up-down direction, and is arranged so as not to contact each soft leg. The hard legs may be arranged so as to be separated from only one of the pair of soft legs and in contact with the other.
Since the front edge portion 40c of the hard leg is in contact with the bumper fascia, the inclination of the rising load in the x-F curve is increased by the reaction force of the hard leg 40 in the initial stage of the collision, and the shock is very good against the absorber. Absorption performance can be imparted.

  The bridge portion 50 is formed by foaming and molding a resin molding material simultaneously with the soft legs 30. That is, the soft leg 30 and the bridge portion 50 are simultaneously molded and integrally formed. Thereby, the dispersion | variation in the shock absorption performance of the absorber 10 reduces.

Moreover, the through-hole 52 which connects the reinforcement 70 side and the bumper fascia 80 side is formed in the bridge part 50 of this embodiment. The bridge portion 50 fixes the soft leg 30 and the hard leg 40 to each other while closing the opening OP1 between the soft leg 30 and the hard leg 40 so that the area ratio is less than half on the bumper fascia 80 side. is doing.
Referring to FIG. 7, the total area So of the opening OP1, the total area Sh of the through hole 52, and the total area Sb of the bridge portion 50 that covers the opening OP1 are determined from the reinforcement 70 to the bumper fascia. Bridge of the portion covering the opening OP1, the through hole 52, and the opening OP1 when projected in the extending direction D4 on the plane PL1 perpendicular to the extending direction D4 of the soft leg 30 and the hard leg 40 directed to 80 It can be expressed by the projected area of the part 50. These projected areas are represented in FIG. In addition, in the same figure, the vertical end view which shows the absorber 10 in the upper stage and the end surface in the position of A3-A3 of FIG. 3 is shown in the upper stage, and the front view which sees the absorber 10 from the front is shown in the lower stage.
In the present embodiment, the openings OP1 are formed at a plurality of locations. If the projected area of each opening OP1 is So1, So2,..., SoN (N is an integer of 1 or more), the total area So of the openings is represented by ΣSoi (i = 1 to N). If the projected area of each through hole 52 is Shi (i = 1 to M, M is an integer of 1 or more), the total area Sh of the through holes is represented by ΣSh. The total area Sb of the bridge portion 50 that covers the opening OP1 is represented by So-Sh. Then, Sb ≧ Sh, that is, the impact surface of the collided object that collided with the bumper fascia by closing the opening OP1 and fixing the soft leg and the hard leg so that the area ratio of the bridge portion is half or less. The impact on the shock absorbing performance due to the orientation of the is sufficient.

  By the way, when the test for measuring the x-F characteristics was repeatedly performed, the variation in the compressive load F was larger when the impactor moving speed was 40 km / h, which was relatively high, compared with 20 km / h, which was relatively slow. It turns out that it grows. It is preferable that the variation in the shock absorbing performance is small. Therefore, by forming the thin portion 41 and the slit 42 in the hard leg 40, variation in the shock absorbing performance of the absorber 10 is reduced.

The thin portion 41 is formed on the hard leg 40 along the longitudinal direction D <b> 2 of the bumper fascia 80. The thin wall portion 41 is formed in a boundary portion 51 between the deformation allowable space SP1 and the bridge portion 50. Thereby, the hard leg 40 is easy to bend from the boundary part 51 at the time of impact input. As shown in FIG. 5 and the like, the thin-walled portion 41 of the present embodiment is on the upper and lower hard legs 40A, 40B facing each other, that is, on the lower surface 40b of the upper hard leg 40A and the upper surface 40a of the lower hard leg 40B. It is formed in a groove shape. Of course, the thin-walled portion may be formed only on one of the upper and lower surfaces of the hard leg, or may be formed on both the upper and lower surfaces of the hard leg. In addition, the thin-walled portion may be formed not only continuously along the longitudinal direction (D2) of the hard leg but also intermittently with a certain interval.
Since the thin leg 41 is formed in the hard leg 40, a bending start point can be created when an impact is input, and the bending position and the bending range are stabilized. Thereby, the dispersion | variation in the shock absorption performance of the absorber 10 is suppressed. Further, as shown in FIG. 6 and the like, since the thin leg portion 41 of the hard leg is provided in the thinning portion 20 adjacent to the bridge portion 50, the thin portion 41 serves as a starting point for bending the hard leg. It functions stably. For this reason, the variation in the shock absorbing performance of the absorber 10 is further suppressed.

The slit 42 is formed to extend forward from the bumper reinforcement 70 side (rear edge portion 40 d) toward the bumper fascia 80 in the hard leg 40. The slit 42 is characterized in that a tip portion extending forward is connected to the thin portion 41. Since the tip end of the slit 42 is substantially connected to the boundary portion 51 between the deformation-permitted space and the bridge portion, the hard leg 40 is easily bent from the boundary portion 51 when an impact is input. It can also be said that the slits 42 of the present embodiment are formed toward the rear in the hard leg 40 so as to project from the thin portion 41 to the thinned portion 20 so that the rear edge portion 40d opens. As shown in FIG. 5 and the like, a plurality of upper and lower hard legs 40A and 40B are formed at intervals in the longitudinal direction D2 of the bumper fascia. The intervals between the slits 42 may be equal intervals as in the present embodiment, or may not be equal intervals. By providing a slit in the hard leg, the bending deformation amount and bending range of the hard leg when a pedestrian's lower limb collides with the bumper fascia can be adjusted, and the variation in the shock absorbing performance of the absorber 10 can be suppressed. Can do.
And by forming the thin part 41 and the slit 42 in the hard leg 40 at the same time, it is possible to effectively reduce the variation in the shock absorbing performance.

In this embodiment, by further forming the extended portion 43 on the hard leg 40, the impact on the impact absorbing performance due to the direction of the collision surface of the colliding object colliding with the bumper fascia 80 is reduced.
The extension part 43 is formed to bend along the facing surface 70a of the bumper reinforcement 70 to the bumper fascia 80 at the rear edge portion 40d of the hard leg. A plurality of extending portions 43 are arranged at intervals along the longitudinal direction D2 of the bumper fascia at the rear edge portion 40d of the hard leg. Each of the extending portions 43 of the present embodiment is alternately extended to the opposite side in the rear edge portion 40d of the hard leg, and is formed in a strip shape with a certain interval on each side. As shown in FIG. 5 and the like, each of the hard legs 40A and 40B has a plurality of first extending portions extending upward perpendicular to the extending direction (front-rear direction D1) of the main body portion of the hard legs. 43A and a plurality of second extending portions 43B extending downward perpendicular to the extending direction D1 of the main body portion of the hard leg are formed.

When the above-mentioned extension part is not formed on the hard leg, if the collision angle of the collision object that collides with the bumper fascia 80 is shifted from the extension direction (front-rear direction D1) of the main part of the hard leg in the up-down direction D3, a plate shape is formed. The main body portion of the formed hard leg easily falls down in the vertical direction, the initial load peak in the load-displacement curve decreases, and the impact absorption amount decreases. By adding the extension part 43 to the rear edge portion 40d of the hard leg, even if the collision angle of the colliding object is shifted in the vertical direction D3 (for example, about 4 °), the main body portion of the hard leg falls in the vertical direction. It becomes difficult, and it is possible to obtain shock absorption performance close to the case of no deviation (0 °). Therefore, by providing the extended portion 43 on the hard leg 40, the impact angle dependency of the shock absorbing performance of the absorber 10 can be reduced.
Further, by forming the extended portions 43 alternately on the upper and lower sides of the hard leg 40, the above-described collapse prevention function is further exhibited, and at the same time, an increase in the initial load is suppressed as much as possible in the load-displacement curve. be able to.

Resins such as thermoplastic resins and thermosetting resins used for foam molding can be used as the resin constituting the resin molding material for forming the soft legs and bridges, and the impact absorption performance is improved. From the viewpoint and the viewpoint of easy molding, thermoplastic resins such as polystyrene, polypropylene, polystyrene / polyethylene copolymer, and the like can be used. In addition, when forming an absorber by foaming a thermoplastic resin, after forming a large number of expandable resin particles impregnated with a foaming agent in a bead-shaped plastic and pre-foamed at a predetermined magnification, the absorber was shaped. A large number of expandable resin particles may be filled into a mold and further heated and foamed to form a bead foam by molding, or foamed by mixing a foaming agent with plastic. The foamed molded body may be formed by extruding and molding plastic from a predetermined die. For the expandable resin particles, expanded polypropylene (EPP), expanded polystyrene (EPS) or the like is preferably used. As the foaming agent, a volatile foaming agent that generates hydrocarbons such as butane and pentane, an inorganic foaming agent that generates carbon dioxide gas such as ammonium carbonate, and the like can be used. The foaming ratio of the foamed molded product is, for example, 20 to 50 times.
Moreover, although the resin molding material may be composed of only a resin and a foaming agent, an additive such as a filler may be included in the resin molding material. The blending ratio of each material in the resin molding material is 50% by weight (preferably 65% by weight or more) of the resin and 50% by weight or less (preferably 35% by weight) of the additive from the viewpoint of sufficiently retaining the properties of the resin. % Or less).

The density of the flexible legs are preferably 0.01~0.18g / cm ^3, more preferably 0.018~0.07g / cm ^3, more preferably 0.02~0.03g / cm ^3. It is preferable to set the density to be equal to or higher than the lower limit because the compressive load is appropriately increased and good compressive load characteristics can be obtained and the impact energy can be absorbed sufficiently. On the other hand, if the density is less than the above upper limit, the compressive load does not increase too much, and the amount of displacement of the soft leg until the compressive load exceeds the allowable limit to the “bottomed state” increases, and the impact energy is sufficiently absorbed. This is preferable.

The density of the crosslinking portions is preferably 0.01~0.18g / cm ^3, more preferably 0.018~0.07g / cm ^3, more preferably 0.02~0.03g / cm ^3. It is preferable to set the density to be equal to or higher than the lower limit because the compressive load is appropriately increased and good compressive load characteristics can be obtained and the impact energy can be absorbed sufficiently. On the other hand, if the density is less than the above upper limit, the compressive load does not increase too much, and the amount of displacement of the soft leg until the compressive load exceeds the allowable limit to the “bottomed state” increases, and the impact energy is sufficiently absorbed. This is preferable.

Synthetic resins are preferable for the resins (including elastomers) constituting the resin molding material for forming the hard legs, and thermoplastic resins are particularly preferable from the viewpoint of imparting appropriate impact absorbability to the hard legs. It is also possible to use a functional resin. The thermoplastic resin is preferably an olefin resin such as polypropylene or polyethylene, a resin obtained by adding an elastomer to an olefin resin, or the like from the viewpoint of imparting particularly suitable shock absorption to the hard leg. Additives such as fillers may be added to the resin material. The compounding ratio of the additive is, for example, a weight ratio equal to or less than the weight ratio of the resin from the viewpoint of sufficiently exhibiting the properties of the resin. Injection molding, press molding, extrusion molding, or the like can be used for molding the resin molding material.
Charpy impact strength of resin molding material for forming hard legs (Charpy impact strength specified in JIS K7111-1 “Plastics – Determination of Charpy impact properties” at the time of establishment in 2006) is 20 J / m ² The above is preferable, and 30 J / m ² or more is more preferable. The reason for setting the Charpy impact strength to be equal to or more than the lower limit is that the hard leg is appropriately bent and deformed by reducing cracking of the hard leg at the time of impact input.
The density of the hard legs can be, for example, 0.9 to 1.2 g / cm ³ (more preferably 1.0 to 1.1 g / cm ³ ).

  The ratio of the length L1 in the front-rear direction D1 of the bridge portion 50 to the length L0 in the front-rear direction D1 of the absorber 10 is preferably 0.20 to 0.65, and more preferably 0.40 to 0.50. When the ratio is equal to or higher than the lower limit, the soft leg and the hard leg are sufficiently fixed to each other at the bridge portion, and even if the collision surface of the colliding object is deviated from the outer surface of the bumper fascia in the vertical section, the soft leg or It is preferable because the hard legs are less likely to fall in the same direction, and the impact energy can be absorbed sufficiently. If the ratio is less than or equal to the upper limit, the length L2 in the front-rear direction of the thinned portion 20 is sufficiently long. As a result, sufficient bending deformation of the hard leg occurs during impact input, and the reaction force applied from the absorber to the collision object Is preferable because it does not become excessive before the impact energy is sufficiently absorbed and good impact absorption performance is obtained. The length L1 in the front-rear direction of the bridge portion can be set to, for example, 6 to 105 mm, and the length L2 in the front-rear direction of the cutout portion 20 can be set to, for example, 9 to 120 mm.

  The ratio of the thickness (L11, L15 in FIG. 6) of the soft leg 30 to the length L2 in the front-rear direction of the thinned portion 20 is preferably 0.25 to 0.6, and preferably 0.3 to 0.5. Is more preferable. If the ratio is equal to or greater than the lower limit, even if the collision surface of the collision object in the vertical cross section deviates from the vehicle outer surface of the bumper fascia, the soft leg and the hard leg are less likely to fall in the same direction, and sufficiently absorb the impact energy. This is preferable. When the ratio is less than or equal to the upper limit, the reaction force applied from the absorber to the impacted object does not become excessive before the impact energy is sufficiently absorbed, and good impact absorbing performance can be obtained. In addition, the thickness L11, L15 of the up-down direction of a soft leg can be 5-40 mm, for example.

  The thickness L13 of the hard leg 40 in the vertical direction D3 is preferably 1.0 to 3.0 mm, and more preferably 1.8 to 2.2 mm. If the thickness L13 is greater than or equal to the lower limit, the compressive load becomes sufficiently large at the initial stage when an impact is input, and even if the collision surface of the collision object in the vertical cross section deviates from the outer surface of the bumper fascia, It is preferable because the hard legs are less likely to fall in the same direction, and the impact energy can be absorbed sufficiently. When the thickness L13 is less than or equal to the upper limit, the hard leg is easily bent and deformed when an impact is input, and the compressive load does not become excessive at the initial stage, and good shock absorbing performance is obtained. The ratio of the thickness L13 in the vertical direction D3 of the hard leg 40 to the length L0 in the front-rear direction D1 of the absorber 10 is, for example, 0.01 to 0.07 (more preferably 0.02 to 0.05). be able to.

The ratio of the thickness D3 in the vertical direction D3 (L12, L14 in FIG. 6) to the length L0 in the front-rear direction D1 of the absorber 10 is preferably 0.05 to 0.4, and 0.08 to 0.34. Is more preferable. When the ratio is equal to or higher than the lower limit, a sufficient space for allowing bending deformation of the rigid legs is secured, and the compression load is not excessive at the initial stage when an impact is input, so that favorable shock absorbing performance can be obtained. . If the ratio is less than the upper limit, even if the hard leg falls when the impact is input, it hits the soft leg and is supported by the soft leg, and the compression load is sufficiently maintained at the later stage of the displacement of the hard leg, and the impact energy is sufficiently absorbed. Is preferable. In addition, 5-15 mm is preferable and, as for the thickness L12 and L14 of the up-down direction of a thinning part, 7.5-12.5 mm is more preferable.
The ratio of the length L2 of the thinned portion 20 to the length L0 in the front-rear direction D1 of the absorber 10 is preferably 0.35 to 0.80, and more preferably 0.50 to 0.60. It is preferable that the ratio is equal to or more than the lower limit, since the bending deformation of the hard leg is not hindered when an impact is input, and a good shock absorbing performance can be obtained. If the ratio is less than the upper limit, even if the collision surface of the colliding object deviates from the vehicle outer surface of the bumper fascia, the hard legs are less likely to fall in the same direction, and the impact energy can be absorbed sufficiently. preferable.
The diameter of the through hole (d1 in FIG. 7) when viewed through the pair of substantially semi-cylindrical through holes 52 that sandwich the hard leg 40 is larger than the thickness L13 of the hard leg, and the thickness L12 of the hollow portion that sandwiches the hard leg. , L14 and the total thickness L13 of the rigid legs L12 + L13 + L14 or less are preferable. Thereby, the impact on the impact absorbing performance due to the direction of the collision surface of the colliding object colliding with the bumper fascia can be reduced.

  The width W1 (see FIG. 9) of the thin portion 41 is preferably 0.2 to 6 mm, and more preferably 0.5 to 3 mm. 5-60% is preferable and, as for depth L16 (refer FIG. 6) of the thin part 41 with respect to plate | board thickness L13 of the hard leg 40, 10-30% is more preferable. If the width W1 and the depth L16 are equal to or greater than the lower limit, it is preferable to suppress the bending of the hard leg 40 not starting from the thin portion 41 when an impact is input, and the width W1 and the depth L16 are less than or equal to the upper limit. If it is present, it is preferable that the hard leg 40 can be prevented from cracking from the thin portion 41 at the time of impact input or the amount of impact absorbed energy can be reduced without generating a required initial load.

The interval L21 (see FIG. 9) between the slits 42 is preferably 50 to 400 mm, and more preferably 100 to 300 mm. If the distance L21 is equal to or greater than the lower limit, a decrease in the amount of energy absorbed by the absorber 10 due to a decrease in the initial load generated when the collision object collides can be suppressed as much as possible, and the distance L21 is equal to or smaller than the upper limit. If so, the shock absorbing performance can be sufficiently stabilized, which is preferable.
The width L22 of the slit 42 is preferably 1 to 3 mm.

The extension portions 43 have a thickness of 1 to 2 mm, a width L23 (see FIG. 9) of 5 to 15 mm, lengths L12 and L14 (see FIG. 6) of 5 to 15 mm, and an interval L24 between the alternately extending portions 43 ( A rectangular shape of 0 to 20 mm is preferable. Of course, the shape of the extended portion 43 is not limited to a rectangular shape, and can be replaced with various shapes such as a semicircular shape and a trapezoidal shape.
In addition, in FIG. 6 etc., the front-end | tip of the extension part 43 is contacting the soft leg 30, However, the front-end | tip of the extension part 43 does not need to contact the soft leg 30. FIG. In the latter case, the length of the extended portion 43 is shorter than the thickness of the thinned portion 20 in the vertical direction D3.

(2) Bumper absorber manufacturing method:
The hard leg 40 can be formed using various known techniques. For example, a granular raw material of thermoplastic resin such as polypropylene is supplied to an injection molding machine with a heater, and the raw material is heated and melted by a heater to be melted in a predetermined mold having a shape of a hard leg. A hard leg can be formed by injecting and molding the thermoplastic resin in a state, and cooling the mold to solidify the resin. When forming a hard leg using a thermosetting resin, the liquid thermosetting resin is injected into a predetermined mold and then the mold is heated to cure the resin, or It can be formed by adding a curing agent to the thermosetting resin and injecting it into the mold and then curing the resin after a predetermined time. Of course, a hard leg can also be formed by extrusion molding or press molding.

  FIG. 10 schematically shows a method for forming the soft leg 30 and the bridge portion 50. In this molding method, a metal molding die MD1 having cavities corresponding to the soft legs 30 and the bridge portions 50 is used, and the mold is simultaneously filled with foamable resin particles and heated by vapor pressure or the like. Tighten. The mold MD1 includes a main body part MD2, a lid part MD3, and a plurality of medium molds MD4. As the mold MD1, a mold having a plurality of vapor holes having a diameter smaller than the diameter of the bead-shaped resin particles (expandable resin particles) and matched to the shape of the absorber 10 can be used. The medium-size MD 4 is used for forming the thinned portion 20 in the soft leg 30, forming the through hole 52 in the bridge portion 50, and forming a slit for inserting the hard leg 40 in the foam molded product.

In order to mold the soft leg 30 and the bridge portion 50, first, a resin molding material containing a foaming agent is put into the molding die MD1. Then, at the position of the middle size MD 4, while forming the hollow portion 20 in the soft leg 30 and forming the through hole 52 in the bridge portion 50, the resin molding material is foamed to form the bridge portion 50 and the soft leg 30. Mold and integrate at the same time.
Here, when bead-like resin particles (foamable resin particles) containing a foaming agent are used for the resin molding material containing the foaming agent, the absorber can be easily formed by thermoforming. For example, a foaming agent may be added to a particulate thermoplastic resin such as polypropylene and pre-foamed into beads to form a large number of bead-shaped resin particles. The diameter of the vapor hole of the mold is assumed to be smaller than the diameter of the bead-shaped resin particles. Next, a large number of bead-shaped resin particles are filled in the mold and the mold is clamped. Furthermore, water vapor whose temperature is raised by a predetermined heater up to a temperature at which the thermoplastic resin constituting the bead-like resin particles is heated and melted is introduced into the mold. Then, the inside of the mold can be heated, and the bead-like resin particles are further foamed, and the bead-like resin particles are bonded while being melted and bonded to the resin plate to form an absorber. When the mold is opened after the mold is cooled, a resin foam molded product in which the soft legs 30 and the bridge portions 50 are integrally molded can be taken out.
And the absorber 10 is formed by inserting the hard leg 40 in the said resin foam molded product.

  In order to adjust the density of the resin foam molded article, the amount of foaming agent impregnated into the bead-shaped resin particles and the expansion ratio may be adjusted. For example, if the blending ratio of the foaming agent added to the particulate thermoplastic resin is increased, the foaming ratio is increased and the density is decreased, and if the blending ratio of the foaming agent added to the particulate thermoplastic resin is decreased, the foaming ratio is increased. Smaller and higher density. Further, if the weight of the bead-shaped resin particles filled in the mold is increased, the expansion ratio is decreased and the density is increased. If the weight of the bead-shaped resin particles filled in the mold is decreased, the expansion ratio is increased. The density becomes smaller.

  In addition to the manufacturing method described above, as shown in Japanese Patent Application Laid-Open No. 2007-326481, after setting the resin plate constituting the hard leg 40 in the mold, the cavity is filled with expandable resin particles, It is also possible to use a manufacturing method in which the bridge portion, the soft leg, and the hard leg are integrated by performing mold clamping simultaneously with heating with pressure or the like.

(3) Action and effect of bumper absorber:
In the present absorber 10, a deformation-allowable space SP1 in which the hard legs are not restrained is formed between the soft legs 30 formed by foaming the resin molding material and the hard legs 40 formed of the resin molding material. As shown by a two-dot chain line in FIG. 11, the deformation-permitting space SP1 allows bending deformation of the hard leg 40 starting from the thin portion 41 when an impact is input. Here, when a collision object such as a pedestrian collides with the bumper fascia 80, the deformation of the hard leg 40 is not hindered. Therefore, as shown in FIG. On the other hand, in the hard leg 40, the reaction force (compression load F2) rapidly increases and reaches a peak in the initial stage, and then the reaction force rapidly decreases. Since the reaction force (compression load F3) on the collision object is a reaction force combining the soft leg 30 and the hard leg 40, a substantially constant reaction force acts on the collision object over a long period of displacement of the absorber. The absorption amount of the impact energy is an energy amount obtained by integrating the compression load F3 by the displacement x until the compression load F3 exceeds the allowable limit compression load F4 to become a “bottomed state”. It becomes possible to absorb the collision energy appropriately, and good shock absorption performance can be obtained.
In addition, although an absorber will become heavy when an absorber is formed with a steel plate, since the absorber of this embodiment is formed with the resin molding material, it can be made lighter than a steel plate type.

In addition, the soft leg 30 and the hard leg 40 are fixed to each other while the bridge portion 50 closes the opening OP1 between the soft leg 30 and the hard leg 40 on the bumper fascia 80 side so that the area ratio is less than half. Therefore, as shown in the lower part of FIG. 8, there is little or no opening on the bumper fascia 80 side in the absorber 10.
In the absorber of the present invention, as shown in FIG. 11, the soft leg 30 and the hard leg 40 are fixed to each other by the bridge portion 50 so that the opening OP <b> 1 is closed on the bumper fascia 80 side. As a result, even if the collision surface of the colliding object that has collided with the bumper fascia 80 is not perpendicular to the direction D1 connecting the reinforcement 70 and the bumper fascia 80, the input load at the time of collision is a large surface of the hard leg 40 Therefore, the phenomenon that the soft leg 30 and the hard leg 40 fall only in a certain direction is avoided. Therefore, the impact on the impact absorbing performance due to the direction of the collision surface of the collision object can be reduced.

  Further, it is not necessary to form a structure for holding the bumper fascia 80 side of the soft leg 30 or the hard leg 40 in the bumper fascia 80. Therefore, according to the bumper absorber, it is possible to reduce the influence on the impact absorbing performance due to the direction of the collision surface of the colliding object colliding with the bumper fascia without complicating the structure of the bumper fascia.

Further, since the thin leg portion 41 of the hard leg is formed along the longitudinal direction D2 of the bumper fascia at the boundary portion 51 between the deformation allowable space and the bridge portion, as shown by a two-dot chain line in FIG. Sometimes, the hard leg 40 is easily bent from the boundary portion 51 as a starting point. Further, since the slits 42 of the hard legs extend from the bumper reinforcement 70 side toward the bumper fascia 80 and are connected to the thin wall portion 41, the hard legs 40 are easily bent from the boundary portion 51 when an impact is input. Become. And since the thin part 41 and the slit 42 are simultaneously formed in the hard leg 40, the dispersion | variation in shock absorption performance reduces effectively.
In addition, since a plurality of extended portions 43 are arranged at intervals in the rear edge portion 40d of the hard leg, the influence on the impact absorbing performance due to the direction of the collision surface of the colliding object colliding with the bumper fascia 80 is reduced. Can be made.

(4) Modification:
As disclosed in Japanese Patent Laid-Open No. 2007-326481, a convex portion that abuts against the plate-like hard leg 40 in the thinned portion 20 may be formed. Further, the plate-like hard leg 40 and the thinned portion 20 may be provided unevenly on the lower side in the absorber.
Like the bumper absorber 11 shown in FIGS. 13 and 14, the bridging portion 50 may cover the edge 40 c on the bumper fascia 80 side of the plate-like hard leg 40 and be separated from the bumper fascia 80. Since the bridge portion 50 includes the front edge portion 40c of the hard leg, and the hard leg 40 is covered with the resin foam molding forming the bridge portion without penetrating the bridge portion 50, it is input to the absorber 10. The impact load applied is once received by the bridge portion 50 and then transmitted to the hard leg 40. In the illustrated example, the hard leg 40 is not provided with an extending portion, the thin portion 41 is formed on the upper surface of the upper hard leg 40, and the thin portion 41 is formed on the lower surface of the lower hard leg 40. Yes. Although not shown, each hard leg 40 is formed with a slit extending from the bumper reinforcement 70 side toward the bumper fascia 80 and connected to the thin portion 41. This absorber 11 can also reduce variation in shock absorption performance.

  Like the bumper absorber 12 shown in FIG. 15 and FIG. 16, the bridging portion 50 completely closes the opening OP <b> 1 between the soft leg and the hard leg on the bumper fascia 80 side, and connects the soft leg 30 and the hard leg 40. You may make it fix mutually. The length L4 in the front-rear direction D1 of the hole 53 and the thickness L3 in the front-rear direction D1 of the bridge portion 50 on the front side of the hole 53 may be set according to the shock absorbing performance of the absorber 12. In the illustrated example, the hard leg 40 is not provided with an extending portion, and a groove along the longitudinal direction D2 of the bumper fascia is formed on the upper surface and the lower surface of the hard leg 40 to form the thin portion 41. Although not shown, each hard leg 40 is formed with a slit extending from the bumper reinforcement 70 side toward the bumper fascia 80 and connected to the thin portion 41. This absorber 12 can also reduce variation in shock absorption performance.

  Like the bumper absorber 13 shown in FIG. 17, a claw-like locking projection 44 is formed on the front edge portion 40 c of the hard leg 40, and the locking projection 44 is engaged with the bumper fascia 80 side of the bridge portion 50. A concave locking portion 54 to be stopped may be formed. When the hard leg 40 is inserted into the bridge portion 50 in order to manufacture the absorber 13, the locking protrusion 44 is locked to the locking portion 54, so that the hard leg 40 is fixed to the bridge portion 50. Then, the locking protrusions 44 locked to the locking portion 54 can prevent the hard legs 40 from dropping from the absorber 13 when the absorber 13 is transported.

In the various embodiments described above, the soft leg, the hard leg, and the bridge portion may be formed in a bent shape such as a corrugated shape while the longitudinal direction is oriented in the horizontal direction, or the longitudinal direction is oriented in a direction other than the horizontal direction. It may be arranged.
Only one of the above-mentioned thinning portions may be formed on the absorber. Only one of the hard legs may be provided on the absorber. In this case, only one opening may be formed between the soft leg and the hard leg on the bumper fascia side. Only one soft leg may be formed on the absorber. For example, the absorber of the present invention can be configured by arranging a pair of plate-like hard legs without contacting a top and bottom of a single soft leg.
Only one through hole of the bridge portion may be formed in the absorber. When providing a some hard leg in an absorber, you may form the through-hole connected with a some hard leg in a bridge part.
The slit may extend toward the bumper fascia from the bumper reinforcement side to a position beyond the bridge portion.

(5) Example:
EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated concretely, this invention is not limited by an Example.
[Example 1]
The rigid legs were injection molded using polypropylene NJ602G (Charpy impact strength 63 J / m ² ) manufactured by Sun Allomer Co., Ltd. so that the length in the front-rear direction was 44 mm, the length in the vehicle width direction was 200 mm, and the thickness was 2.0 mm. A molded product was used. In the hard leg, a thin portion was formed at the boundary between the bridge portion and the thinned portion, and a slit connected to the thin portion was formed so as not to cross the bridge portion from the bumper reinforcement side. The thin part had a width of 2 mm and a depth of 0.35 mm (17.5% of the thickness of the hard leg). Two slits were formed for each rigid leg, with an interval of 100 mm and a width of 1 mm.
As the expandable resin particles, polypropylene bead-like pre-expanded particles (φ3 mm, density 0.03 g / cm ³ , expansion ratio 30 times) manufactured by JSP Corporation were used.

The absorber sample has a substantially rectangular parallelepiped shape, three soft legs and two hard legs, and alternately arrange the soft legs and hard legs, and connect the front side of the soft legs and the front side of the hard legs. A bridging part that fixes the soft leg and the hard leg to each other was formed. In addition, in the bridge portion, six through holes having a diameter of 15 mm were formed for one rigid leg so as to be equidistant with a center distance of 50 mm, for a total of twelve. Here, the length of the absorber sample in the front-rear direction is 44 mm, the length of the absorber sample in the vehicle width direction is 300 mm, and the length L2 in the front-rear direction of each cutout portion is 25 mm (the length L1 in the front-rear direction of the bridge portion) 19 mm), the vertical lengths L12 and L14 of each cutout portion were 7.5 mm, and the vertical thicknesses L11 and L15 of each soft leg were both 22 mm. Therefore, the vertical length of the absorber sample is 100 mm.
First, a large number of the foamable resin particles are filled in a mold having a plurality of vapor holes, high-temperature steam is introduced into the mold from the vapor holes, and the density of the soft legs and the bridge portions is 0. A large number of expandable resin particles were subjected to foam molding so as to obtain 0.03 g / cm ^3, and the soft legs and the bridge portions were integrally molded. Next, hard legs were inserted into the bridge portion to form the absorber sample of Example 1. Three samples were formed.

[Comparative Example 1]
Three absorber samples of Comparative Example 1 were formed in the same manner as in Example 1 except that the thin leg and the slit were not formed on the hard leg.

[Comparative Example 2]
Three absorber samples of Comparative Example 2 were formed in the same manner as Example 1 except that no slit was formed on the hard leg.

[Comparative Example 3]
Three absorber samples of Comparative Example 3 were formed in the same manner as in Example 1 except that the thin part was not formed on the hard leg.

[Comparative Example 4]
A thin leg that is 5mm away from the boundary between the bridge part and the cut-out part on the hard leg is formed on the hard leg, and the slit extends from the bumper reinforcement side to the thin part so as not to cross the thin part. Formed. Otherwise, three absorber samples of Comparative Example 4 were formed in the same manner as Example 1.

[Test method]
As a bumper cover equivalent material, a polypropylene injection molded product (meat of 200 mm in the vehicle width direction, 100 mm in the first and third examples, and 90 to 130 mm in the second example) in the vehicle width direction. A thickness of 3 mm) was used.
As the compressive load measuring device, a device having a rectangular parallelepiped receiving tool to which an absorber sample was attached and a leg-type pusher moving horizontally at a constant speed of 40 km / h toward the receiving device was used. The leg type pusher is made of steel S45C and has a cylindrical shape of Φ75 × 300 mm, has a built-in load sensor for measuring the compression load F, and a compression load F according to the moving position of the impactor by a control device (not shown). Is detected. The displacement x of the absorber sample was the moving distance from the position where the leg-shaped pusher contacts the absorber sample.
The absorber samples of Example 1 and Comparative Examples 1 to 4 are sequentially attached by bringing the ends of the soft leg and the rigid leg into contact with the support of the compressive load measuring device, and the front surface of the absorber sample. A bumper cover (bumper fascia) equivalent material was placed in contact with.
As shown in the upper part of FIG. 18, with respect to each absorber sample, the front side was slightly lowered using a jig to shift the extending direction of the soft leg and the hard leg by 4 ° from the horizontal direction.
For each absorber sample with a bumper cover equivalent material placed on the front, the leg-shaped pusher was moved horizontally toward the support and collided from the front, and the compression load F was detected according to the position of the pusher. . The compression load F (unit: kN) against the displacement x (unit: mm) of the test sample was graphed. Further, the maximum difference when the maximum difference in the compression load F was maximized at the same displacement x between the displacement 0 mm and the displacement 37 mm corresponding to 85% compression was obtained.

[Test results]
19 to 23 are graphs showing the compression load F with respect to the displacement x in each example. Moreover, the maximum difference of the compressive load F was smaller in the case of Example 1 than the case of Comparative Examples 1-4 as follows.
Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4
0.6kN 2.0kN 1.5kN 2.0kN 2.0kN
As shown in the above results, by forming a thin portion at the boundary between the deformation-allowable space and the bridge portion with respect to the hard leg, and forming a slit connected to the thin portion, variation in shock absorption performance can be achieved. It was confirmed that it can be reduced.

[Example 2]
Two absorber samples identical to those in Example 1 were formed.

[Example 3]
A plurality of rectangular strip-like extended portions with a thickness of 2 mm, a width of 11 mm, a length of 7.5 mm, and a staggered extension portion of 0 mm at the rear edge of the rigid leg are staggered vertically. Arranged. Otherwise, two absorber samples of Example 2 were formed in the same manner as Example 1.

[Comparative Example 5]
As the hard leg, as shown in FIG. 24, a hard leg having a thickness of 2 mm, a length of 7.5 mm, and an extended portion that is continuous in the longitudinal direction D2 is provided above and below the rear edge. Otherwise, two absorber samples of Example 5 were formed in the same manner as Example 1.

[Test method]
As shown in the upper part of FIG. 18, the front side is slightly lowered using a jig, and the extending direction of the soft legs and the hard legs is shifted by 4 ° from the horizontal direction, so that the absorber samples of Examples 1 and 2 and Comparative Example 5 are compared. Then, the leg-shaped pusher was moved horizontally toward the support and collided from the front, and the compression load F was detected according to the movement position of the pusher. The compression load F (unit: kN) against the displacement x (unit: mm) of the test sample was graphed.
Further, as shown in the lower part of FIG. 18, the extending direction of the soft leg and the hard leg is set as the horizontal direction, and the leg-type pusher is directed toward the receiving member with respect to the absorber samples of Examples 1 and 2 and Comparative Example 5. It moved horizontally and made it collide from the front, and the compression load F was detected according to the moving position of the pusher. The compression load F (unit: kN) against the displacement x (unit: mm) of the test sample was graphed.

[Test results]
25 to 27 are graphs showing the compression load F with respect to the displacement x in each example. In Example 1, when the collision angle is 4 °, the peak of the initial load (displacement 17.5 mm) is about 1 kN lower than that in the case of the collision angle 0 °. The drop in the initial load peak (displacement 17.5 mm) when the collision angle was 4 ° with respect to the case was suppressed to about 0.3 kN.
On the other hand, in the case of Comparative Example 5, the peak of the initial load (displacement of 17.4 mm) in the case of the collision angle of 4 ° with respect to the case of the collision angle of 0 ° was increased by about 0.9 kN. In this case, the reaction force against the collision object may exceed a desired reaction force.
As shown in the above results, the bumper fascia collides with the bumper fascia by arranging a plurality of extended parts bent along the opposite surface to the bumper fascia in the bumper reinforcement at the rear edge of the hard leg. It was confirmed that the impact on the impact absorbing performance due to the direction of the impact surface of the impacted object can be reduced.

  Note that the present invention is not limited to the above-described embodiments and modifications, and the configurations disclosed in the above-described embodiments and modifications are mutually replaced or the combination is changed, the known technology, and the above-described configurations. Configurations in which the respective configurations disclosed in the embodiment and the modified examples are mutually replaced or combinations are changed are also included.

The principal part disassembled perspective view which illustrates the principal part of the motor vehicle which employ | adopted the bumper absorber. The perspective view which shows the example of the absorber for bumpers seeing from the front side. The perspective view which shows the B1 part of the absorber shown in FIG. 2 seeing from the front side. The perspective view which shows the B1 part of the absorber shown in FIG. 2 seeing from a rear side. The perspective view which shows the example of a 2nd energy absorption part seeing from the front side. FIG. 4 is a vertical sectional view showing the absorber shown in FIG. 2 in a cross-sectional view at a position A1-A1 in FIG. 3; FIG. 4 is a vertical sectional view showing the absorber shown in FIG. 2 in a cross-sectional view at a position A2-A2 in FIG. 3. The figure which shows the area ratio which plugs up the opening between the 1st, 2nd energy absorption parts shown in FIG. The figure which shows the 2nd energy absorption part shown in FIG. 3 seeing from an up-down direction and back. The disassembled perspective view which illustrates typically a mode that the absorber for bumpers is manufactured. The vertical cross section which illustrates a mode that the absorber was assembled | attached to the bumper. The figure of the graph format which illustrates the compressive load with respect to the displacement x of an absorber. The perspective view which expands and shows the part corresponded to B1 part of FIG. 2 in the absorber which concerns on a modification. The vertical sectional view which shows the absorber which concerns on a modification on a cross-sectional view in the position equivalent to A1-A1 of FIG. The perspective view which expands and shows the part corresponded to B1 part of FIG. 2 in the absorber which concerns on a modification. The vertical sectional view which shows the absorber which concerns on a modification on a cross-sectional view in the position equivalent to A1-A1 of FIG. The vertical sectional view which shows the absorber which concerns on a modification on a cross-sectional view in the position equivalent to A1-A1 of FIG. The side view which illustrates typically the method of measuring shock absorption performance. The figure which shows the change of the compressive load with respect to displacement about Example 1. FIG. The figure which shows the change of the compressive load with respect to a displacement about the comparative example 1. FIG. The figure which shows the change of the compressive load with respect to a displacement about the comparative example 2. FIG. The figure which shows the change of the compressive load with respect to a displacement about the comparative example 3. FIG. The figure which shows the change of the compressive load with respect to a displacement about the comparative example 4. FIG. The perspective view which shows the external appearance of the hard leg used in the comparative example 5. FIG. FIG. 6 is a diagram showing changes in compressive load with respect to displacement in Example 2. FIG. 9 is a diagram illustrating changes in compressive load with respect to displacement in Example 3. The figure which shows the change of the compressive load with respect to a displacement about the comparative example 5. FIG.

Explanation of symbols

1 ... car,
10-13 ... Bumper absorber,
20 ... Meat extraction part,
30 ... Soft leg (first energy absorption part), 30a ... Upper surface, 30b ... Lower surface,
30c ... front edge (bumper fascia side edge),
30d ... Rear edge (bumper reinforcement side edge),
40 ... Hard leg (second energy absorbing part), 40a ... Upper surface, 40b ... Lower surface,
40c ... front edge (bumper fascia side edge),
40d ... rear edge (bumper reinforcement side edge),
41 ... Thin part,
42 ... Slit,
43 ... Extension site,
44 ... locking projection,
50 ... Bridge part, 51 ... Boundary part between deformation allowable space and bridge part,
52 ... Through hole, 53 ... Hole, 54 ... Locking part,
70 ... Bumper reinforcement, 70a ... Outside surface (opposite surface),
72 ... partition wall,
80 ... Bumper fascia, 80a ... Vehicle outside surface, 80b ... Vehicle inside surface,
100 ... Bumper,
D1 ... front-rear direction, D2 ... vehicle width direction, D3 ... vertical direction,
M1 ... impacted object, M2 ... impact surface,
MD1 ... mold, MD2 ... main body, MD3 ... lid, MD4 ... medium,
OP1 ... Opening,
SP1: Deformable space,

Claims (5)

A bumper absorber provided between a bumper reinforcement in a vehicle and a bumper fascia outside the bumper reinforcement,
A first energy absorbing portion formed by foaming a resin molding material, provided along the longitudinal direction of the bumper fascia, and extending from the bumper reinforcement toward the bumper fascia;
Formed with a resin molding material, provided along the longitudinal direction of the bumper fascia, and at a position where a space allowing deformation of itself is formed between the bumper reinforcement and the first energy absorbing portion. A second energy absorbing portion extending from the bumper reinforcement toward the bumper fascia,
Formed by foaming a resin molding material, arranged facing the vehicle inner side of the bumper fascia, and provided with a bridging portion that fixes the first energy absorbing portion and the second energy absorbing portion to each other,
In the second energy absorbing portion, a thin portion along the longitudinal direction of the bumper fascia is formed at a boundary portion between the space and the bridge portion, and from the bumper reinforcement side toward the bumper fascia. The bumper absorber is characterized in that a slit is formed to extend to connect to the thin portion.   2. The bumper absorber according to claim 1, wherein a plurality of the slits are formed in the second energy absorbing portion at intervals in a longitudinal direction of the bumper fascia.   In the second energy absorbing portion, a plurality of extending portions bent along the surface facing the bumper fascia in the bumper reinforcement are arranged at intervals on the edge on the bumper reinforcement side. The bumper absorber according to claim 1 or 2, characterized in that.   4. The bumper absorber according to claim 3, wherein each of the extending portions extends alternately to the opposite side at an edge of the second energy absorbing portion on the bumper reinforcement side. 5.   5. The resin molding material according to claim 1, which is obtained by foaming a resin molding material in a molding die and molding the first energy absorbing portion and the bridging portion simultaneously. Bumper absorber.

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