JP6475051B2 - Energy absorbing structure - Google Patents

Description

  The present invention relates to an energy absorbing structure that collapses and absorbs impact energy when a vehicle collision occurs.

  The vehicle is provided with an energy absorbing member that is crushed when a collision occurs and absorbs impact energy. A typical example of the energy absorbing member is an energy absorbing member disposed between the bumper beam and the front frame. Conventionally, energy absorbing members have been made of metal such as iron, but in recent years, cylindrical energy absorbing members made of fiber reinforced resin (CFRP) mixed with carbon fibers have been put into practical use in order to reduce the weight of vehicle bodies. It has become. The cylindrical energy absorbing member is crushed along the axial direction, so that the amount of impact energy absorbed is stabilized.

  On the other hand, in Patent Document 1, in an energy absorbing device that absorbs impact energy by pressing an energy absorbing member axially from one end thereof with a pressing plate and compressing and destroying it, the pressing plate is brought into its initial posture. An energy absorbing device provided with a guide mechanism that holds the energy absorbing member so as to be movable in the axial direction while being held is disclosed. Specifically, in the energy absorbing device of Patent Document 1, a rod extending downward in a direction parallel to the axis of the energy absorbing member is fixed to the lower surface side of the pressing plate, and the support plate on the rear end side is It has a hole provided at a position corresponding to the rod or a U-shaped notch. Thereby, when an impact load is applied to the pressing plate, the pressing plate moves in the axial direction of the energy absorbing member.

JP 7-217690 A

  However, the energy absorbing device described in Patent Document 1 uses a rod as a guide mechanism, and the pressure plate can be moved in parallel by moving the rod in the axial direction. However, when inputting a load from an oblique direction, etc. The rod may be bent and deformed. When the rod is deformed, the guide function cannot be performed, and an unexpected load may be applied in the process of collapsing the energy absorbing device.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to suppress the deformation of the rod when an impact load is input, and an energy absorbing member by a guide mechanism using the rod. It is an object of the present invention to provide an energy absorbing structure that can ensure the collapse in the axial direction.

  In order to solve the above problems, according to an aspect of the present invention, a cylindrical energy absorbing member made of a fiber reinforced resin that is crushed in the axial direction and absorbs collision energy when a collision load is input, and the energy absorbing member A pressing member that contacts the end of the energy absorbing member and transmits the collision load to the energy absorbing member, a holding member that contacts an end of the energy absorbing member on the rear end side, and the holding member from the pressing member And at least one rod provided extending in the axial direction of the energy absorbing member, and a guide hole provided in the holding member through which the rod is inserted, the axial length of the portion in contact with the rod An energy absorbing structure comprising: the guide hole having a length smaller than a thickness of the holding member.

  The openings at both ends of the guide hole may have an enlarged taper shape.

  In the cross section including the axis of the guide hole in the holding member, the inner surface of the guide hole may have an arc shape.

  The rod may be inserted into a holding hole provided in the pressing member, and an axial length of the holding hole in a portion in contact with the rod may be smaller than a thickness of the pressing member.

  Openings at both ends of the holding hole may have an enlarged taper shape.

  In the cross section including the axis of the holding hole in the pressing member, the inner surface of the holding hole may have an arc shape.

  As described above, according to the energy absorbing structure of the present invention, the deformation of the rod at the time of input of impact load is suppressed, and the axial collapse of the energy absorbing member is ensured by the guide mechanism using the rod. Can do.

It is a side view which shows the energy absorption structure concerning one Embodiment of this invention. It is explanatory drawing which shows the energy absorption structure concerning the embodiment. It is sectional drawing which shows the energy absorption structure concerning the embodiment. It is explanatory drawing which shows the mode at the time of the collapse of the energy absorption structure concerning the embodiment. It is sectional drawing which shows the conventional energy absorption structure. It is explanatory drawing which shows the mode at the time of the collapse of the conventional energy absorption structure. It is sectional drawing which shows the modification 1 of an energy absorption structure. It is sectional drawing which shows the modification 2 of an energy absorption structure.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol. In the present specification and drawings, a plurality of components having substantially the same functional configuration may be distinguished by adding different alphabets after the same reference numeral. However, when it is not necessary to particularly distinguish each of a plurality of constituent elements having substantially the same functional configuration, only the same reference numerals are given.

<1. Configuration of energy absorbing structure>
With reference to FIGS. 1-3, the structural example of the energy absorption structure 100 concerning one Embodiment of this invention is demonstrated. FIG. 1 is a side view of an energy absorbing structure 100 according to the present embodiment. In FIG. 1, the upper side is the front side of the vehicle, and the lower side is the rear side of the vehicle. FIG. 2 is a top view of the energy absorbing structure 100 as viewed from above. FIG. 3 is a cross-sectional view of the XX cross section of FIG. 2 as viewed in the direction of the arrow. In the following description, the front side of the vehicle may be referred to as the upper side, and the rear side of the vehicle may be referred to as the lower side.

  The energy absorbing structure 100 includes an energy absorbing member 10. The energy absorbing member 10 is held by the pressing member 20 on the upper side and held by the holding member 40 on the lower side. The pressing member 20 is fixed in the vicinity of a portion that can receive a collision load when the vehicle collides. In the present embodiment, the pressing member 20 is fixed to the bumper beam 2 via a stay or the like (not shown). The holding member 40 is joined to the front end side of a front frame (not shown). Therefore, the energy absorbing member 10 is disposed between the bumper beam and the front frame.

(1-1. Energy absorbing member)
The energy absorbing member 10 is a member that absorbs collision energy by receiving a collision load and collapsing when the vehicle collides with a preceding vehicle, an obstacle, or another object. The energy absorbing member 10 also plays a role of appropriately transmitting the load to the front frame when the collision load is large. The energy absorbing member 10 is made of fiber reinforced resin (FRP). In the present embodiment, the energy absorbing member 10 is formed of carbon fiber reinforced resin (CFRP) using a thermosetting resin and carbon fiber, and can achieve high strength and light weight.

  The energy absorbing member 10 made of FRP develops a load by being crushed while being continuously broken at the time of a collision, and can realize stable impact energy absorption with little load fluctuation. Further, the energy absorbing member 10 made of FRP has a characteristic that there is little crushing residue and a large amount of shock energy is absorbed per unit weight. The energy absorbing member 10 made of FRP can be, for example, a composite material using an assembly composed of braids and vertical cords.

  The reinforcing fiber used for the fiber reinforced resin constituting the energy absorbing member 10 is not particularly limited. For example, carbon fibers, glass fibers, aramid fibers, and the like, or reinforced fibers that combine these can be used. Among these, carbon fibers are preferably included from the viewpoint of high mechanical properties and ease of strength design.

  The fiber reinforced resin matrix resin constituting the energy absorbing member 10 may be a thermosetting resin or a thermoplastic resin. In the case of a thermosetting resin, examples of the main material include an epoxy resin, an unsaturated polyester resin, a vinyl ester resin, a phenol resin, a polyurethane resin, and a silicon resin, and one or two or more of these are exemplified. A mixture of these may also be used. When these thermosetting resins are employed as the matrix resin, it is possible to add an appropriate curing agent or reaction accelerator to the thermosetting resin.

  In the case of a thermoplastic resin, the main materials include, for example, polyethylene resin, polypropylene resin, polyvinyl chloride resin, ABS resin, polystyrene resin, AS resin, polyamide resin, polyacetal resin, polycarbonate resin, thermoplastic polyester resin, PPS ( Polyphenylene sulfide) resin, fluororesin, polyetherimide resin, polyetherketone resin, polyimide resin, etc. are exemplified, and one of these or a mixture of two or more may be used. These thermoplastic resins may be used alone, as a mixture, or as a copolymer. In the case of a mixture, a compatibilizer may be used in combination. Further, brominated flame retardants, silicon-based flame retardants, red phosphorus and the like may be added as flame retardants. It is preferable to use a thermoplastic resin for an automobile member that is required to be relatively mass-produced from the viewpoint of ease of molding and mass productivity.

  In this case, examples of the thermoplastic resin used include polyolefin resins such as polyethylene and polypropylene, polyamide resins such as nylon 6 and nylon 66, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyether ketone, Examples of the resin include polyether sulfone and aromatic polyamide. Among them, the plastic matrix resin is preferably at least one selected from the group consisting of polyamide, polyphenylene sulfide, polypropylene, polyether ether ketone, and phenoxy resin.

  The energy absorbing member 10 has a hollow cylindrical shape, and is arranged so that the axial direction is along the front-rear direction of the vehicle. In the present embodiment, a hollow cylindrical energy absorbing member 10 is used. The upper end portion of the energy absorbing member 10 has a tapered shape that decreases in diameter toward the end portion. By having such a tapered shape, when the energy absorbing member 10 receives an input of a collision load, the tip of the energy absorbing member 10 is easily developed while being crushed toward the inner space. The size of the energy absorbing member 10 can be appropriately designed according to the size of the vehicle, the amount of impact energy absorbed to be obtained, the weight of the energy absorbing member 10, and the like. For example, the axial length of the energy absorbing member 10 is 130 to 200 mm, the inner space has a diameter of 40 to 60 mm, and a thickness of about 4 to 5 mm.

(1-2. Guide mechanism)
The energy absorbing structure 100 has a guide mechanism for causing the energy absorbing member 10 to be crushed in the axial direction. The guide mechanism includes a pressing member 20, a holding member 40, and a guide rod 30. The pressing member 20 is disposed in contact with the upper end of the energy absorbing member 10. The upper end of the energy absorbing member 10 is joined to the pressing member 20 using, for example, an adhesive. The pressing member 20 is made of a metal typified by iron or the like.

  The holding member 40 is disposed in contact with the lower end of the energy absorbing member 10. The lower end of the energy absorbing member 10 is joined to the holding member 40 using, for example, an adhesive. The holding member 40 is made of a metal typified by iron or the like. The holding member 40 has a role of receiving an impact load input to the energy absorbing structure 100 through the energy absorbing member 10 and transmitting it to the front frame when a collision occurs, and has a certain strength. Required. Therefore, the thickness of the holding member 40 can be about 1 to 5 mm.

  A guide rod 30 is fixed to the pressing member 20. The guide rod 30 is a member having a substantially perfect circular cross section. The guide rod 30 is inserted through a holding hole 20 a provided in the pressing member 20. The guide rod 30 has a head 31 having a diameter larger than the diameter of the holding hole 20a at the tip thereof. For example, the guide rod 30 is fixed to the pressing member 20 by being press-fitted into the holding hole 20a or by being joined to the holding hole 20a using an adhesive or the like. In the present embodiment, four guide rods 30 are fixed to the pressing member 20.

  The guide rod 30 is inserted through a guide hole 40 a provided in the holding member 40 on the rear end side. For example, the guide rod 30 is fixed to the holding member 40 by being lightly press-fitted into the guide hole 40a or by being joined to the guide hole 40a using an adhesive or the like. The holding hole 20a and the guide hole 40a have a substantially circular cross-sectional shape orthogonal to the axial direction.

  In such a guide mechanism, rattling of the energy absorbing structure 100 due to vibration during traveling of the vehicle is prevented during a non-collision. On the other hand, when a collision occurs and an impact load is input, the pressing member 20 moves downward while the guide rod 30 fixed to the pressing member 20 is guided by the guide hole 40a. Along with this movement, the pressing member 20 causes the energy absorbing member 10 to be crushed in the axial direction.

  Here, as shown in FIG. 3, in the energy absorbing structure 100 according to the present embodiment, the openings at both ends of the guide hole 40a of the holding member 40 have an enlarged taper shape in which the diameter increases toward the opening end. Have. Therefore, the guide hole 40a is in contact with the guide rod 30 at the central portion in the axial direction and supports the guide rod 30. That is, the axial length of the portion in contact with the guide rod 30 in the guide hole 40 a is shorter than the thickness of the holding member 40.

  Further, in the energy absorbing structure 100 according to the present embodiment, the openings at both ends of the holding hole 20a of the pressing member 20 have an enlarged taper shape whose diameter increases toward the opening end, similarly to the guide hole 40a. Therefore, the holding hole 20a is in contact with the guide rod 30 and supports the guide rod 30 in the central portion in the axial direction. That is, the axial length of the portion in contact with the guide rod 30 in the holding hole 20 a is shorter than the thickness of the pressing member 20.

  Since the guide hole 40a of the holding member 40 has an enlarged taper shape whose diameter increases toward the opening end, the allowable range of the inclination of the guide rod 30 with respect to the axial direction of the guide hole 40a is relatively large. Therefore, even when the guide rod 30 is tilted with respect to the axial direction of the energy absorbing member 10, the guide rod 30 is not easily caught on the edge of the opening of the guide hole 40a. As described above, the thickness of the holding member 40 can be about 1 to 5 mm, but the axial length of the inner surface of the guide hole 40a in contact with the guide rod 30 is, for example, about 1.0 to 1.5 mm. It can be suppressed.

  Thereby, the guide rod 30 is not deformed and is not clogged in the guide hole 40a, and the sliding operation of the guide rod 30 in the guide hole 40a is ensured. That is, even when a collision load is input non-uniformly to the pressing member 20 when an offset collision occurs in front of the vehicle, the plurality of guide rods 30 slide unevenly. The inside of the guide hole 40a is slid without significantly tilting toward the input side of the collision load.

  Further, since the holding hole 20a of the pressing member 20 has an enlarged taper shape whose diameter increases toward the opening end, the allowable range of the inclination of the guide rod 30 with respect to the axial direction of the holding hole 20a becomes relatively large. Therefore, even when the guide rod 30 is tilted with respect to the axial direction of the energy absorbing member 10, deformation of the guide rod 30 due to the edge of the holding hole 20a is suppressed. At this time, since the holding hole 20a has an enlarged taper shape, it may be allowed that the inclination of each guide rod 30 is different. Therefore, the inclination with respect to the axial direction of the energy absorption member 10 in each guide rod 30 is suppressed small. Thereby, the pressing member 20 is easily moved downward, and the energy absorbing member 10 is easily pressed in the axial direction.

<2. State at the time of load input>
FIG. 4 is a diagram illustrating a state of the energy absorbing structure 100 when a load is input nonuniformly to the energy absorbing structure 100. FIG. 4 corresponds to the cross-sectional view shown in FIG. As shown in FIG. 4, when a load is input non-uniformly to the pressing member 20, in the energy absorbing structure 100 according to the present embodiment, the axial direction in which the guide rod 30 and the inner surface of the guide hole 40 a are in contact with each other. Since the length is relatively short, the allowable range of the inclination of the guide rod 30 with respect to the axial direction of the guide hole 40a is relatively large. Therefore, the restriction of the guide rod 30 by the inner surface of the guide hole 40a is easy to be released.

  In addition, since each opening of the guide hole 40a has an enlarged taper shape, the guide rod 30 slides unevenly in the guide hole 40a without being caught by the guide hole 40a while being inclined. At this time, since the holding hole 20a of the pressing member 20 has an enlarged taper shape, the allowable range of the inclination of the guide rod 30 with respect to the axial direction of the holding hole 20a is relatively large, and the axial direction of the energy absorbing member 10 is relatively large. The inclination of the guide rod 30 is kept small. Therefore, the guide rod 30 is easier to slide in the guide hole 40a.

  Therefore, even when a load is input non-uniformly to the energy absorbing structure 100, the energy absorbing member 10 is easily crushed along the axial direction. As described above, the energy absorbing structure 100 according to the present embodiment can generate a load as designed without any unexpected load intervention due to the clogging of the guide rod 30 in the guide hole 40a.

  For comparison, a description will be given of a case where a load is input non-uniformly in an energy absorbing structure that does not have guide holes and holding holes whose openings at both ends have enlarged taper shapes. 5 and 6 show an energy absorbing member provided with a guide mechanism in which the guide hole 4a is a straight hole and the guide rod 3 is fixed to the pressing member 20 by welding or the like. 5 and 6 correspond to FIGS. 3 and 4, respectively.

  As shown in FIGS. 5 and 6, when the guide hole 4a is a straight hole, the guide rod 3 has the same axial length as the thickness of the holding member 4 of about 1 to 5 mm and contacts the inner surface of the guide hole 4a. ing. When the load is input unevenly, the allowable range of the inclination of the guide rod 3 in the guide hole 4a is small, and the guide rod 3 is pressed against the edge of the opening of the guide hole 4a. As a result, as shown in FIG. 6, stress concentrates on the edge of the opening of the guide hole 4 a in contact with the guide rod 3, and the guide rod 3 is deformed.

  As a result, the guide rod 3 is clogged in the guide hole 4a, and an unexpected load other than the load by the energy absorbing member 10 is generated. Therefore, the transition of the energy absorption amount with respect to the crushing stroke amount becomes unstable, and the energy absorption characteristics are deteriorated.

<3. Modification>
Hereinafter, some modified examples of the energy absorbing structure 100 according to the present embodiment will be described. In addition, each modification demonstrated below may be applied independently to the structure demonstrated in the said embodiment, and may be applied to this invention in combination.

(Modification 1)
FIG. 7 is a view showing an energy absorbing structure 100A according to Modification 1, and is a cross-sectional view corresponding to FIG. The energy absorbing structure 100A according to Modification 1 is different from the energy absorbing structure 100 described in the above embodiment in the shapes of the holding hole 20b of the pressing member 20 and the guide hole 40b of the holding member 40. The holding hole 20b and the guide hole 40b have a substantially circular cross-sectional shape perpendicular to the axial direction, and the diameter of the opening side at both ends in the axial direction is larger than the diameter of the central part in the axial direction. . The holding hole 20b and the guide hole 40b are in contact with the guide rod 30 at the diameter-reduced portion in the central portion in the axial direction.

  Also by the energy absorbing structure 100A according to the first modification, when the load is input non-uniformly to the pressing member 20, the restriction of the guide rod 30 by the inner surface of the guide hole 40b is easily released. The guide rod 30 slides non-uniformly in the guide hole 40b without being caught in the guide hole 40b while being tilted. At this time, also in the holding hole 20b of the pressing member 20, the allowable range with respect to the inclination of the guide rod 30 with respect to the axis of the holding hole 20b is relatively large, and the inclination of the guide rod 30 with respect to the axial direction of the energy absorbing member 10 is suppressed. Therefore, the guide rod 30 is easier to slide in the guide hole 40b.

  Therefore, even when a load is input non-uniformly to the energy absorbing structure 100A, the energy absorbing member 10 is easily crushed along the axial direction. As described above, the energy absorbing structure 100A according to the first modification can generate the designed load without any unexpected load intervention due to the clogging of the guide rod 30 in the guide hole 40b.

(Modification 2)
FIG. 8 is a view showing an energy absorbing structure 100B according to the second modification and is a cross-sectional view corresponding to FIG. The energy absorbing structure 100B according to Modification 2 is different in the shape of the holding hole 20c of the pressing member 20 and the guide hole 40c of the holding member 40 from the case of the energy absorbing structure 100 described in the above embodiment. The holding hole 20c and the guide hole 40c have a substantially circular cross-sectional shape orthogonal to the axial direction, and the diameter of the opening side at both ends in the axial direction is larger than the diameter of the central part in the axial direction. Then, it is common with the holding hole 20a and the guide hole 40a described in the above embodiment. In Modification 2, the inner surfaces of the holding hole 20c and the guide hole 40c have an arc shape in a cross section including the axis of the holding hole 20c and the guide hole 40c. The holding hole 20c and the guide hole 40c are in contact with the guide rod 30 at the reduced diameter portion at the central portion in the axial direction.

  Also by the energy absorbing structure 100B according to the second modification, when the load is input non-uniformly to the pressing member 20, the restriction of the guide rod 30 by the inner surface of the guide hole 40c is easily released. The guide rod 30 slides unevenly in the guide hole 40c without being caught in the guide hole 40c while being tilted. At this time, also in the holding hole 20c of the pressing member 20, the allowable range with respect to the inclination of the guide rod 30 with respect to the axis of the holding hole 20c is relatively large, and the inclination of the guide rod 30 with respect to the axial direction of the energy absorbing member 10 is kept small. Therefore, the guide rod 30 is easier to slide in the guide hole 40c.

  In particular, in Modification 2, the inner surfaces of the holding hole 20c and the guide hole 40c are curved surfaces, so that even if the guide rod 30 is inclined in the holding hole 20c and the guide hole 40c, the guide rod 30 and the holding hole 20c. Or it becomes easy to contact | connect the guide hole 40c on a surface, and a stress is easy to be disperse | distributed. Therefore, deformation of the guide rod 30 is easily suppressed, and clogging of the guide rod 30 into the guide hole 40c is easily suppressed.

  Therefore, even when a load is input non-uniformly to the energy absorbing structure 100B, the energy absorbing member 10 is easily crushed along the axial direction. As described above, the energy absorbing structure 100B according to the modified example 2 can express the load as designed without any unexpected load intervention due to the clogging of the guide rod 30 in the guide hole 40c.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

2 Bumper beam 3 Guide rod 4 Holding member 4a Guide hole 10 Energy absorbing member 20 Pressing member 20a, 20b, 20c Holding hole 30 Guide rod 31 Head 40 Holding member 40a, 40b, 40c Guide hole 100, 100A, 100B Energy absorbing structure

Claims (6)

A cylindrical energy absorbing member made of fiber reinforced resin that crushes in the axial direction when absorbing a collision load and absorbs collision energy;
A pressing member that abuts on an end of the energy absorbing member on the front end side and transmits the collision load to the energy absorbing member;
A holding member that comes into contact with an end portion on the rear end side of the energy absorbing member;
At least one rod provided extending from the pressing member to the holding member in the axial direction of the energy absorbing member;
A guide hole provided in the holding member, through which the rod is inserted, wherein the axial length of a portion in contact with the rod is smaller than the thickness of the holding member;
An energy absorbing structure comprising:   The energy absorbing structure according to claim 1, wherein openings at both ends of the guide hole have an enlarged taper shape.   The energy absorption structure according to claim 1 or 2, wherein an inner surface of the guide hole has an arc shape in a cross section including an axis of the guide hole in the holding member. The rod is inserted into a holding hole provided in the pressing member,
The energy absorption structure according to any one of claims 1 to 3, wherein an axial length of the holding hole at a portion in contact with the rod is smaller than a thickness of the pressing member.   The energy absorbing structure according to claim 4, wherein the openings at both ends of the holding hole have an enlarged taper shape. 6. The energy absorbing structure according to claim 4, wherein an inner surface of the holding hole has an arc shape in a cross section including an axis of the holding hole in the pressing member.

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