Part-mounting structure for vehicle body

Abstract: The part-mounting structure comprises a part-mounting portion (6) of a sandwich structure constituted by a core layer (2) and plastic skin layers (1) formed on both surfaces of the core layer, and a part-mounting metal member (7) ,at least one of the skin layers (1) having a tapered recess (4) having a sloped side wall (4a) and a flat bottom wall (4b),the bottom wall being constituted by the skin layers bonded together, the part-mounting metal member having a bottom plate (8),and a pair of side plates (9) vertically extending from the bottom plate substantially on both sides, at least one of the side plates having a dent (10) tapered complementarily to the tapered recess of the sandwich structure. The part-mounting metal member is mounted to the part-mounting portion of the sandwich structure with a surface of the tapered recess of the sandwich structure and a surface of the tapered dent of the part-mounting metal member bonded together by an adhesive. This structure is suitable for mounting various parts such as engines, suspension beams, upper arms, radius rods, dumpers, seat slide rails, etc. to the vehicle body.

Description: The present invention relates to a part-mounting structure for a sandwich structure constituted by a core layer and skin layers, and more particularly to a part-mounting structure for a vehicle body constituted by such a sandwich structure. Recently, to reduce vehicle weights and to increase productivity by reducing vehicle parts, it was proposed to use composite structures such as fiber-reinforced plastics for vehicle bodies, and they are now partly put into practical use. Such composite structures are in general sandwich structures constituted by cores coated with skin layers on both surfaces. Various proposals were made to use foamed plastics for cores (Japanese Patent Publication Nos. 46-36329 and 55-43912, Japanese Utility Model Laid-Open No. 63-30276, U.S. Patent Nos. 4,559,274 and 4,573,707, etc.), and to use honeycomb structures for cores (Japanese Patent Laid-Open No. 47-32521, Japanese Utility Model Laid-Open Nos. 57-114774, 62-174935 and 62-174978, etc.). It was also proposed to use for vehicle bodies sandwich structures whose core portions are partly hollow (Japanese Utility Model Laid-Open No. 62-166136, etc.). However, in such sandwich structures, if parts such as engines, suspension beams, upper arms, radius rods, dumpers, seat slide rails, etc. are mounted to them directly by screws, etc., the screws would not be able to be firmly fixed, and the mounting strength of parts would be insufficient. Particularly, since various parts such as engines mounted to the vehicle body are heavy and subjected to vibrations, mere threading, welding or bonding for mounting the parts onto the skin layers of the sandwich structures would be insufficient in mounting strength. In addition, once peeling takes place in the adhesion layer, the breakage thereof would propagate quickly. Also, since a floor panel, a lower part of the vehicle body, is provided with various parts such as seats, a side brake, a change lever, etc., and is subjected to a large stress, it should have part-mounting structures having extremely high strength. Further, if part-mounting brackets are used to mount parts to the vehicle body, the reduction of the number of parts and vehicles' weights would not be achieved. In addition, since the brackets are generally bulky, the mounting space would be inevitably large. In addition, since the seat slide rails are portions to which the overall weight of a passenger is applied, and are likely to be subjected to a large load when the seat is slid , the seat slide rail-mounting structure is required to have high strength. Accordingly, an object of the present invention is to provide a structure for mounting various parts such as engines, suspension beams, upper arms, radius rods, dumpers, etc. to a vehicle body of a sandwich structure constituted by a core layer and skin layers with sufficient strength. Specifically, an object of the present invention is to provide a part-mounting portion of a vehicle body of a sandwich structure to which a part is fixedly mounted. "Product Engineering" Vol. 44, No. 4, April 1973 (New York, USA), pages 29 to 31, discloses, in a sandwich structure comprising a core layer and plastics skin layers formed on both surfaces of said core layer, a part-mounting portion including a flat wall area formed by said skin layers bonded together, said flat wall area being at the bottom of a tapered recess formed in at least one of said skin layers and having a sloping side wall. The present invention is characterised by the said tapered recess being formed in the region of an edge of the sandwich structure with the recess being open toward the said edge, the sandwich structure having a flange portion formed by the said skin layers bonded together along the said edge, and the said bottom wall of the tapered recess being coplanar with said flange portion. We have found that by providing a sandwich structure with a tapered recess in its part-mounting portion, and by fixedly mounting a part-mounting metal member having a complementary tapered dent to the tapered recess of the sandwich structure by an adhesive, a load exerted from a part such as a front suspension beam, an upper arm, an engine, a radius rod, a dumper, etc. mounted to the part-mounting metal member can be transmitted smoothly to wide areas of the overall skin layers of the sandwich structure, thereby avoiding the concentration of stress in the sandwich structure. We have further found that by providing a vehicle body of a sandwich structure with an engine-mounting portion comprising a tapered recess and a projected portion having an engaging portion at its lower end, and by fixedly mounting an engine-mounting metal member having a tapered dent complementary to the tapered recess of the sandwich structure and a bent portion engageable with the projected portion to the engine-mounting portion of the sandwich structure by an adhesive and a bolt, a load of an engine mounted to the engine-mounting metal member can be transmitted smoothly to wide areas of the overall skin layers of the sandwich structure, thereby avoiding the concentration of stress in the sandwich structure. In a preferred arrangement, the part-mounting portion is provided together with a part-mounting metal member having a bottom plate, and a pair of side plates vertically extending from the bottom plate substantially on both sides, at least one of the side plates having a dent tapered complementarily to the tapered recess of the sandwich structure. A part-mounting structure according to a first embodiment of the present invention is constituted by a core layer and plastic skin layers formed on both surfaces of the core layer, and a part-mounting metal member, at least one of the skin layers having a tapered recess having a sloped side wall and a flat bottom wall, the bottom wall being constituted by the skin layers bonded together, the part-mounting metal member having a bottom plate, and a pair of side plates vertically extending from the bottom plate substantially on both sides, at least one of the side plates having a dent tapered complementarily to the tapered recess of the sandwich structure, and the part-mounting metal member being mounted to the part-mounting portion of the sandwich structure with a surface of the tapered recess of the sandwich structure and a surface of the tapered dent of the part-mounting metal member bonded together by an adhesive. The pair of front suspension beam-mounting portions according to a second embodiment of the present invention are formed in a lower edge portion of a front frame at front and rear positions (two positions) in a vehicle body of a sandwich structure constituted by a core layer and plastic skin layers formed on both surfaces of the core layer, and in each front suspension beam-mounting portion, at least one of the skin layers having a tapered recess having a sloped side wall and a flat bottom wall, the bottom wall being constituted by the skin layers bonded together, and the tapered recess opening toward the edge of the sandwich structure. A metal member for mounting a front suspension beam to each front suspension beam-mounting portion of a vehicle body of a sandwich structure constituted by a core layer and plastic skin layers according to the second embodiment of the present invention may be provided and preferably has a bottom plate, and a pair of side plates vertically extending from the bottom plate substantially on both sides, at least one of the side plates having a dent tapered complementarily to the tapered recess of the sandwich structure. A front suspension beam-mounting structure according to the second embodiment of the present invention may thus comprise (a) a pair of front suspension beam-mounting portions of a vehicle body of a sandwich structure constituted by a core layer and plastic skin layers, the front suspension beam-mounting portions being formed in a lower edge portion of a front frame at front and rear positions (two positions), and in each front suspension beam-mounting portion, at least one of the skin layers having a tapered recess having a sloped side wall and a flat bottom wall, the bottom wall being constituted by the skin layers bonded together, the tapered recess opening toward the edge of the sandwich structure, and (b) a pair of front suspension beam-mounting metal members each having a bottom plate and a pair of side plates vertically extending from the bottom plate substantially on both sides, at least one of the side plates having a dent tapered complementarily to the tapered recess of the sandwich structure, each of the front suspension beam-mounting metal members being mounted to each of the front suspension beam-mounting portions of the sandwich structure with a surface of the tapered recess of the sandwich structure and a surface of the tapered dent of the front suspension beam-mounting metal member bonded together by an adhesive. The pair of upper arm-mounting portions according to the third embodiment of the present invention are formed in a lower edge portion of a front frame at front and rear positions (two positions) in a vehicle body of a sandwich structure constituted by a core layer and plastic skin layers formed on both surfaces of the core layer, in each upper arm-mounting portion, at least one of the skin layers being provided with a tapered recess having a sloped side wall and a flat bottom wall, the bottom wall being constituted by the skin layers bonded together, and the tapered recess opening toward the edge of the sandwich structure. A metal member for mounting an upper arm to each upper arm-mounting portion of a vehicle body of a sandwich structure according to the third embodiment of the present invention may be provided and preferably has a bottom plate; a pair of first side plates vertically extending from one side of the bottom plate substantially on both lateral sides, and a pair of second side plates extending from the other side of the bottom plate for supporting the upper arm; at least one of the first side plates having a dent tapered complementarily to the tapered recess of the sandwich structure. An upper arm-mounting structure according to the third embodiment of the present invention may comprise (a) a pair of upper arm-mounting portions of a vehicle body of a sandwich structure constituted by a core layer and plastic skin layers, the upper arm-mounting portions being formed in a lower edge portion of a vehicle frame of the sandwich structure at front and rear positions (two positions), in each upper arm-mounting portion, at least one of the skin layers having a tapered recess being provided with a sloped side wall and a flat bottom wall, the bottom wall being constituted by the skin layers bonded together, and the tapered recess opening toward the edge of the sandwich structure; and (b) a pair of upper arm-mounting metal members each having a bottom plate, a pair of first side plates vertically extending from one side of the bottom plate substantially on both lateral sides, and a pair of second side plates extending from the other side of the bottom plate for supporting the upper arm, at least one of the first side plates having a dent tapered complementarily to the tapered recess of the sandwich structure; each of the upper arm-mounting metal members being mounted to each of the upper arm-mounting portions of the sandwich structure with surfaces of the tapered recesses of the sandwich structure and surfaces of the tapered dents of the first side plates of the upper arm-mounting metal members bonded together by an adhesive. A first engine-mounting portion of a vehicle body of a sandwich structure constituted by a core layer and plastic skin layers according to a fourth embodiment of the present invention is constituted by a core layer and plastic skin layers formed on both surfaces of said core layer, at least one of said skin layers having a tapered recess having a sloped side wall and a flat bottom wall, and said bottom wall being constituted by said skin layers bonded together. A first metal member for mounting an engine to a first engine-mounting portion of a vehicle body of a sandwich structure according to the fourth embodiment of the present invention may be provided and preferably has a bottom plate, a pair of first side plates vertically extending from one side of the bottom plate substantially on both lateral sides, and a pair of second side plates extending from the other side of the bottom plate for supporting the engine; at least one of the first side plates having a dent tapered complementarily to the tapered recess of the sandwich structure. A first engine-mounting structure according to the fourth embodiment of the present invention may comprise (a) a first engine-mounting portion of a vehicle body of a sandwich structure constituted by a core layer and plastic skin layers formed on both surfaces of said core layer, at least one of said skin layers having a tapered recess having a sloped side wall and flat bottom wall, and said bottom wall being constituted by said skin layers bonded together; and (b) a first metal member for mounting an engine to the engine-mounting portion, the engine-mounting metal member having a bottom plate, a pair of first side plates vertically extending from one side of the bottom plate substantially on both lateral sides, and a pair of second side plates extending from the other side of the bottom plate for supporting the engine; at least one of the first plates having a dent tapered complementarily to the tapered recess of the sandwich structure. Some embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which:- Fig. 1 is a partially cut perspective view showing a part-mounting portion of a sandwich structure according to a first embodiment of the present invention; Fig. 2 is a perspective view showing a part-mounting metal member to be bonded to the part-mounting portion shown in Fig. 1; Fig. 3 is a partially cut perspective view showing the part-mounting metal member of Fig. 2 fixedly mounted to the part-mounting portion of Fig. 1; Fig. 4 is a cross-sectional view taken along the line A-A in Fig. 3; Fig. 5 is a schematic side view showing the positions of front suspension beam-mounting portions in the vehicle body of a sandwich structure according to the second embodiment of the present invention; Fig. 6 is a schematic side view showing the front suspension beam fixed to the front suspension beam-mounting portions of the sandwich structure; Fig. 7 is a schematic side view showing the positions of the upper arm-mounting portions in the vehicle body of a sandwich structure; Fig. 8 is a perspective view showing an upper arm-mounting metal member to be bonded to the upper arm-mounting portion shown in Fig. 7 according to a third embodiment of the present invention; Fig. 9 is a partially cut perspective view showing the upper arm-mounting metal member of Fig. 8 fixedly mounted to the upper arm-mounting portion of Fig. 1; Fig. 10 is a cross-sectional view taken along the line B-B in Fig. 9; Fig. 11 is a schematic side view showing the position of the first engine-mounting portion in the vehicle body of a sandwich structure; Fig. 12 is a perspective view showing a first engine-mounting metal member to be bonded to the fourth engine-mounting portion shown in Fig. 11 according to a fourth embodiment of the present invention; Fig. 13 is a partial perspective view showing a pair of side members of the first engine-mounting metal member of Fig. 12 to be fixedly mounted to the first engine-mounting portion of Fig. 11 according to the fourth embodiment of the present invention; Fig. 14 is a partially cut perspective view showing the first engine-mounting metal member shown in Fig. 12 fixed to the first engine-mounting portion shown in Fig. 11; and Fig. 15 is a cross-sectional view taken along the line C-C in Fig. 14. Fig. 1 is a partial perspective view showing the part-mounting portion of a sandwich structure according to the first embodiment of the present invention. The sandwich structure is constituted by a core layer 2 made of a foamed material and a pair of skin layers 1, 1 formed on both surfaces of the core layer 2. In an edge portion of the sandwich structure, both skin layers 1, 1 are bonded together to form a flange portion 3. In the part-mounting portion 6 of this sandwich structure, the skin layers 1, 1 are provided with tapered recesses 4, 4 symmetrically formed on both surfaces. Each tapered recess 4 comprises a sloped side wall 4a and a flat bottom wall 4b, and in the bottom wall 4b both skin layers 1, 1 are bonded together. In this embodiment, the tapered recess 4 is opened toward the edge portion of the sandwich structure, and the bottom wall 4b is coplanar with the flange portion 3. The sloped side wall 4a is in an elongated shape, and is constituted by flat side wall portions and conical side wall portions. Incidentally, the bottom wall 4b is provided with a plurality of holes 5 for receiving bolts for mounting a part-mounting metal member. Fig. 2 is a perspective view showing a part-mounting metal member 7 to be fixedly mounted to the part-mounting portion shown in Fig. 1. The part-mounting metal member 7 comprises a bottom plate 8, and a pair of side plates 9, 9 vertically extending from the bottom plate 8 substantially on both sides. Each of the side plates 9, 9 is provided with a tapered dent 10, 10 which is shaped complementarily to the tapered recess 4 of the sandwich structure shown in Fig. 1. Incidentally, since a space between these tapered dents 10, 10 receives the bottom wall 4b constituted by both skin layers bonded together, its gap is equal to or slightly larger than the thickness of the bottom wall 4b. Opposing portions 11, 11 of the tapered dents 10, 10 are also provided with a plurality of holes 12 for bolts at positions corresponding to the holes 5. The bottom plate 8 of the part-mounting metal member 7 is provided with a plurality of bolt holes 15 for mounting a part. An edge portion of the bottom plate 8 is bent upwardly to provide a bent fringe portion 13. This bent fringe portion 13 is provided with notches 14, 14 (only one is shown in Fig. 2) at centers of sides perpendicular to the side plates 9, 9 for permitting the flange portion 3 of the sandwich structure to extend therethrough. Fig. 3 is a partially cut perspective view showing the part-mounting metal member 7 of Fig. 2 fixedly mounted to the part-mounting portion 6 of the sandwich structure shown in Fig. 1, and Fig. 4 is an A-A cross-sectional view showing the part-mounting structure shown in Fig. 3. As is clear from Fig. 4, the tapered recesses 4, 4 of both skin layers 1, 1 of the sandwich structure are in complete contact with the tapered dents 10, 10 of the part-mounting metal member 7 in entire surfaces. In this state, the tapered recesses 4, 4 and the tapered dents 10, 10 are fixedly bonded together by an adhesive. As shown in Fig. 4, since the holes of the tapered dents 10, 10 of the side plates 9, 9 are aligned with the holes 5 of the bottom wall 4b of the tapered recesses 4, 4, they are fixed by bolts 16 extending therethrough. A part can be mounted to the bottom plate 8 of the part-mounting metal member 7 by bolts threaded to the holes 15. A load exerted by the part mounted is transmitted to both side plates 9, 9 via the bottom plate 8 of the part-mounting metal member 7 and then uniformly transmitted via the tapered dents 10, 10 to the tapered recesses 4, 4 of the both skin layers 1, 1 fixed to the part-mounting metal member 7. Since the tapered recesses 4, 4 are fixed to the complimentarily tapered dents 10, 10, a load of any direction can be sustained by some portions of the part-mounting portion having enough strength. Specifically speaking, in the figure, when an upward load is applied, the load is sustained by the upper, conical side wall portions of the tapered recesses 4, 4. On the other hand, when a downward load is applied, the load is sustained by the surfaces 1a and 9a. In general, a shear strength of adhesion is much larger than a peeling strength, the structure in which a load is sustained by this shearing strength is extremely advantageous in strength. Further, when a lateral load is applied, both lateral side wall portions of the tapered recesses 4, 4 sustain the load sufficiently. In addition, when a torsional load is applied, the torsional load can be sustained by the overall surfaces of the adhered walls of the tapered recesses 4, 4, because both overall tapered surfaces of the sandwich structure and the part-mounting metal member are fixed by adhesion. Moreover, since the tapered dents 10, 10 are fixed on both surfaces, a torsional load of any direction is transmitted as a pressing force to the tapered recesses in some portions on both surfaces. In other words, a force of peeling direction in a portion is inevitably a force in a pressing direction in another portion. Accordingly, the torsional load is sufficiently sustained by some of those portions. This means that a torsional load is not applied only as a peeling force to the bonded boundaries between the tapered recesses 4, 4 and the tapered dents 10, 10. Incidentally, even when one of the skin layers 1, 1 is flat, the skin layers 1, 1 are fixed to both side plates 9, 9 of the part-mounting metal member 7 simultaneously on both surfaces of the tapered recess 4 and the flat portion, so that it is sufficiently strengthened against a torsional load. As described above, a load exerted from the part is fully sustained by the bonded portions between the tapered recesses 4, 4 of the skin layers 1, 1 and the tapered dents 10, 10 of the part-mounting metal member 7 and between the portion 1a in Fig. 1 and the portion 9a in Fig. 2. However, for the purposes of reinforcement and fail-safe, the part-mounting metal member is fixed to the part-mounting portion 6 of the sandwich structure by bolts 16, so that the part-mounting metal member 7 is not detached even when the adhesion is broken. Bent fringe portion 13 of the bottom plate 8 of the part-mounting metal member 7 is for reinforcement of the bottom plate 8, and the notches 14, 14 provided in this bent fringe portion 13 are for permitting the flange portion 3 of the sandwich structure to extend therethrough. Accordingly, the flange portion 3 itself is not notched, serving to maintain the strength of the sandwich structure itself. The part-mounting structure according to the first embodiment of the present invention has been explained referring to the attached drawings, but the present invention is not restricted thereto, and any modifications can be made that would be apparent to a skilled reader. For instance, instead of providing a pair of tapered recesses symmetrically in the skin layers, only one skin layer can be provided with a tapered recess while another skin layer is kept flat, so that a part-mounting metal member having side plates, only one of which is provided with a tapered dent, can be used. With respect to the shape of the tapered recesses of the skin layers, it is not restricted to an elongated one. As long as it has a sloped side wall, it may have any shape depending upon its applications. As described above in detail, the part-mounting structure according to the first embodiment of the present invention can serve to transmit a load applied to the part to the overall surfaces of the sandwich structure. Also, since the part-mounting metal member is fixed to the sandwich structure with the tapered recesses of the sandwich structure adhered to the complimentarily tapered dents of the part-mounting metal member, the part-mounting structure of the present invention is sufficiently strong to a load applied to a part in any direction including vertical, lateral and torsional directions. Fig. 5 is a schematic side view showing the positions of the front suspension beam-mounting portions of Fig. 1 in the sandwich structure according to the second embodiment of the present invention. The front suspension beam-mounting portions 18, 19 are provided in a lower edge portion of a front frame 20a, which is a part of the vehicle body constituted by the sandwich structure. A vehicle has a pair of front frames on both lateral sides, and the front frames extend forward from the center portion of the vehicle body inside the front wheels 21a, 21a substantially in parallel therewith. Fig. 5 shows a front frame 20a on the left side, and a front frame on the right side (not shown) is also provided with front suspension beam-mounting portions. In the front suspension beam-mounting portions 18, 19, the rear mounting portion 19 is located at a slightly higher position than the front mounting portion 18. Also the front mounting portion 18 opens just downward, while the rear mounting portion 19 opens toward the downwardly inclined forward direction with respect to the vehicle body. The front suspension beam-mounting portions 18, 19 do not necessarily have the same size, but the shapes of the front suspension-mounting portions are essentially similar to those shown in Fig. 1. A front suspension beam-mounting metal member to be fixedly mounted to the front suspension beam-mounting portion has substantially the same shape as shown in Fig. 1. As shown in Fig. 3, the front suspension beam-mounting metal member can be fixedly mounted to the front suspension beam-mounting portion 6 of the sandwich structure which may be the same as shown in Fig. 1. Fig. 6 schematically shows that the metal members 22, 26 having the shape shown in Fig. 2 and also having dents tapered complementarily to the tapered recesses of the front suspension beam-mounting portion are fixedly mounted to the front suspension beam-mounting portions 18, 19 of the front frame 20a, and that the front suspension beam 30 is mounted to the front suspension beam-mounting metal members 22, 26. The front suspension beam 30 is fixed to the front frame 20a at both ends thereof, with bolts threaded into the holes of the bottom plates 24, 28 of the metal members 22, 26 fixed to the front suspension beam-mounting portions 18, 19 of the front frame 20a at positions shown by the arrows. Extending through a box 31 provided in the front suspension beam 30 at its center position is a leaf suspension extending laterally. The front suspension beam 30 is bent such that its rear end is directed slightly upward. Thus, the front suspension beam 30 is fixed at its rear end to the rear mounting portion 19 substantially in perpendicular to the bottom plate 28 of the metal member 26. Accordingly, the axial direction of the front suspension beam 30 is substantially coincident with the directions of bolts for mounting the front suspension beam 30 to the sandwich structure. By such a structure for mounting the front suspension beam 30 to the front frame 20a, an external force exerted from front is sustained by the bottom plate 28 of the metal member 26, and it is transmitted to the skin layers of the front frame 20a via the side plates of the metal member 26, whereby such an external force can be smoothly transmitted to the vehicle body in parallel with a vehicle floor. Specifically speaking, in the front suspension beam-mounting portion 19, a force exerted from front via the front suspension beam 30 is sustained by the adhesion boundary between the side plates oi the metal member 26 and the skin layers of the sandwich structure, whereby the force can be transmitted to the skin layers of the front frame without concentration in any particular portions. In this case, since the directions of the bolts for mounting the front suspension beam 30 to the metal member 26 are the same as that of the force, the breakage of the bolts can be avoided. As described above, a large force which may be exerted from front by collision, etc. is transmitted to the overall vehicle body through the front suspension beam-mounting metal member 26 fixed to the front suspension beam-mounting portion 19 of the sandwich structure, so that such an external force can be absorbed by a large mass of the overall vehicle body. As a result, the vehicle body of this structure exhibits good shock resistance. The front suspension beam-mounting structure according to the second embodiment of the present invention is strong enough not only to a force from front but also to a force of any direction for the reasons as described above in connection with the first embodiment. As in the case of the part-mounting structure shown in Fig. 3, a load exerted from the front suspension beam is fully sustained by the bonded portions between the tapered recesses 4, 4 of the skin layers 1, 1 and the tapered dents 10, 10 of the front suspension beam-mounting metal member 7 and between the portion 1a in Fig. 1 and the portion 9a in Fig. 2. However, for the purposes of reinforcement and fail-safe, the front suspension beam-mounting metal members 22, 26 are fixed to the front suspension beam-mounting portions 18, 19 of the sandwich structure by bolts 16, so that the front suspension beam-mounting metal members 22, 26 are not detached even when the adhesion is broken. The front suspension beam-mounting structure according to the second embodiment of the present invention has been explained referring to the attached drawings, but the present invention is not restricted thereto, and any modifications can be made. The front suspension beam-mounting structure according to the second embodiment of the present invention can serve to transmit a load applied to the front suspension beam to the overall surfaces of the sandwich structure as described above in connection with the first embodiment. In addition, since the rear end portion of the front suspension beam is bent slightly upward, the axial direction of the bottom plate of the front suspension beam is substantially perpendicular to the front suspension beam-mounting metal member fixed to the front frame at a rear mounting portion thereof. Accordingly, a force exerted from front through the front suspension beam can be sustained by the bottom plate of the front suspension beam-mounting metal member at the rear position. The force is then transmitted to the overall vehicle body smoothly via the side plates of the metal member. Therefore, the front suspension beam-mounting structure of the present invention is sufficiently strong to a shock exerted from front. Fig. 7 is a schematic side view showing the positions of the upper arm-mounting portions of Fig. 1 in the vehicle body of the sandwich structure according to the third embodiment of the present invention. The upper arm-mounting portions 48, 49 are provided in a lower edge portion of a front frame 20a, which is a part of the vehicle body constituted by the sandwich structure. A vehicle has a pair of front frames on both lateral sides, and the front frames extend forward from the center portion of the vehicle body inside the front wheels 21a, 21a substantially in parallel therewith. Fig. 7 shows a front frame 20a on the left side, and a front frame on the right side (not shown) is also provided with the same upper arm-mounting portions. The recesses of the upper arm-mounting portions 48, 49 do not necessarily have the same size, but the shapes of the recesses are essentially similar to the recess 4 shown in Fig. 1. With respect to a rear upper arm, they can be mounted to a rear frame of the vehicle body like the front upper arm. Fig. 8 is a perspective view showing an upper arm-mounting metal member 54 to be fixedly mounted to the upper arm-mounting portion having the same configuration as shown in Fig. 7. The upper arm-mounting metal member 54 comprises a bottom plate 60, and a pair of first side plates 55, 55 vertically extending from one side of the bottom plate 60 substantially on both lateral sides. Each of the first side plates 55, 55 is provided with a tapered dent 56, 56 which is shaped complementarily to the tapered recess 4 of the sandwich structure shown in Fig. 1. Incidentally, since a space between these tapered dents 56, 56 receives the bottom wall 4b constituted by bonded skin layers 1, 1 shown in Fig. 1, its gap is equal to or slightly larger than the thickness of the bottom wall 4b. Opposing portions 59, 59 of the tapered dents 56, 56 are also provided with a plurality of holes 58 for bolts at positions corresponding to the holes 5. The bottom plate 60 of the metal member 54 is also provided with a pair of second side plates 63, 63 extending from the other side thereof for mounting an upper arm. Each side plate 63 is provided with a bent fringe portion 63a and a hole 65 for mounting the upper arm. An edge portion of the bottom plate 60 is bent upwardly to provide a bent fringe portion 61. This bent fringe portion 61 is provided with notches 62, 62 (only one is shown in Fig. 8) at centers of sides perpendicular to the first side plates 55, 55 for permitting the flange portion 3 of the sandwich structure to extend therethrough. Fig. 9 is a partially cut perspective view showing the upper arm-mounting metal member 54 of Fig. 8 fixedly mounted to the upper arm-mounting portion 6 of the sandwich structure, and Fig. 10 is a B-B cross-sectional view showing the upper arm-mounting structure shown in Fig. 9. As is clear from Fig. 10, the tapered recesses 4, 4 of both skin layers 1, 1 of the sandwich structure are in complete contact with the tapered dents 56, 56 of the upper arm-mounting metal member 54 in entire surfaces 4a, 4b. In this state, the tapered recesses 4, 4 and the tapered dents 56, 56 are fixedly bonded together by an adhesive. As shown in Fig. 10, since the holes 58 of the tapered dents 56, 56 of the side plates 55, 55 are aligned with the holes 5 of the bottom wall 4b of the tapered recesses 4, 4, they are fixed by bolts 68 extending therethrough. An upper arm 50 is mounted to the metal member by inserting its ends into the holes 65, 65 of the side plates 63, 63 in the upper arm-mounting portions 48, 49 as schematically shown in Fig. 7. A load applied to the upper arm 50 is uniformly transmitted via both first side plates 55, 55 of the upper arm-mounting metal member 54 to the tapered recesses 4, 4 of the two skin layers 1, 1 to which the upper arm-mounting metal member 54 is fixed. Since the tapered recesses 4, 4 are fixed to the complimentarily tapered dents 56, 56, a load of any direction can always be sustained by some portions of the upper arm-mounting structure having enough strength. Specifically speaking, when an upward load is applied, the load is sustained by the upper, conical side wall portions of the tapered recesses 4, 4. On the other hand, when a downward load is applied, the load is sustained by the surfaces 1a and 55a. In general, a shear strength of adhesion is much larger than a peeling strength, the structure in which a load is sustained by this shearing strength is extremely advantageous in strength. Further, when a lateral load is applied, both lateral side wall portions of the tapered recesses 4, 4 sustain the load sufficiently. In addition, when a torsional load is applied, the torsional load can be sustained by the overall surfaces of the adhered walls of the tapered recesses 4, 4, because both overall tapered surfaces of the sandwich structure and the upper arm-mounting metal member are fixed by adhesion. Moreover, since the tapered dents 56, 56 are fixed on both surfaces, a torsional load of any direction is transmitted as a pressing force to the tapered recesses in some portions on both surfaces. In other words, a force of peeling direction in a portion is inevitably a force in a pressing direction in another portion. Accordingly, the torsional load is sufficiently sustained by some of those portions. This means that a torsional load is not applied only as a peeling force to the bonded boundaries between the tapered recesses 4, 4 and the tapered dents 56, 56. As described above, a load exerted from the upper arm is fully sustained by the bonded portions between the tapered recesses 4, 4 of the skin layers 1, 1 and the tapered dents 56, 56 of the upper arm-mounting metal member 54 and between the portion 1a in Fig. 1 and the portion 55a in Fig. 8. However, for the purposes of reinforcement and fail-safe, the upper arm-mounting metal members are fixed to the upper arm-mounting portions 48, 49 of the sandwich structure by bolts 68, so that the upper arm-mounting metal members are not detached even when the adhesion is broken. Bent fringe portion 61 of the bottom plate 60 of the upper arm-mounting metal member 54 is for reinforcement of the bottom plate 60, and the notches 62, 62 provided in this bent fringe portion 61 are for permitting the flange portion 3 of the sandwich structure to extend therethrough. Accordingly, the flange portion 3 itself is not notched, serving to maintain the strength of the sandwich structure itself. The upper arm-mounting structure according to third embodiment of the present invention has been explained referring to the attached drawings, but the present invention is not restricted thereto, and any modifications can be made as described above in connection with the first embodiment. In addition, as mechanical fastening means in the tapered recess, any other means than bolts, for instance, rivets, etc. may be used. As described above in detail, the upper arm-mounting structure of the present invention can serve to uniformly transmit a load applied to the upper arm to the overall surfaces of the sandwich structure. An engine is fixed to the vehicle body at three points or more. Fig. 11 is a schematic side view showing the position of a first engine-mounting portion 78 having a shape shown in Fig. 1 in the vehicle body of the sandwich structure. The first engine-mounting portion 78 according to the fourth embodiment of the present invention is provided in a lower edge portion of a front frame 20b, which is a part of the vehicle body constituted by the sandwich structure. A vehicle has a pair of front frames on both lateral sides, and the front frames extend forward from the center portion of the vehicle body inside the front wheels 21b, 21b substantially in parallel therewith. In this embodiment, the first engine-mounting portion 78 is formed in a lower edge portion of the front frame on the right side. Incidentally, a recess 79 near the first engine-mounting portion 78 is a portion for mounting a front upper arm. Fig. 12 is a perspective view showing a first engine-mounting metal member 83 to be fixedly mounted to the first engine-mounting portion having the same shape as shown in Fig. 1 according to the fourth embodiment of the present invention, and Fig. 13 is a partial perspective view showing the side plates of the first engine-mounting metal member 83 shown in Fig. 12. The first engine-mounting metal member 83 comprises a bottom plate 90, a pair of first side plates 86, 86 vertically extending from one side of the bottom plate 90 substantially on both lateral sides, and a pair of second side plates 92, 92 extending from the other side of the bottom plate 90 for supporting the engine. In this embodiment, the second side plates 92, 92 are integrally connected at their one ends as shown in Fig. 12. Each of the first side plates 86, 86 is provided with a tapered dent 87, 87 which is shaped complementarily to the tapered recess 4 of the sandwich structure shown in Fig. 1. Incidentally, since a space between these tapered dents 87, 87 receives the bottom wall 4b constituted by bonded skin layers 1, 1 shown in Fig. 1, its gap is equal to or slightly larger than the thickness of the bottom wall 4b. Opposing portions 88, 88 of the tapered dents 87, 87 are also provided with a plurality of holes 89 for bolts at positions corresponding to the holes 5. In this embodiment, the bottom plate 90 of the first metal member 83 may also be provided with a pair of third side plates 93, 93 extending therefrom on the same side as the second side plates 92, 92 for mounting an upper arm. In this embodiment, the third side plates 93, 93 are integrally connected at their one ends as shown in Fig. 12. Each side plate 93 is provided with a hole 85 for mounting the upper arm. An edge portion of the bottom plate 90 is bent upwardly for reinforcement. The second and third side plates are also provided with bent portions in their edges for reinforcement. Incidentally, since the direction of supporting the engine and the direction of supporting the upper arm are different, the bottom plate 90 of the first engine-mounting metal member 83 is bent in compliance with the difference in the above supporting direction. Fig. 14 is a partially cut perspective view showing the first engine-mounting metal member 83 of Fig. 12 fixedly mounted to the first engine-mounting portion having the same shape as the part-mounting portion 6 of the sandwich structure shown in Fig. 1, and Fig. 15 is a C-C cross-sectional view showing the first engine-mounting structure shown in Fig. 14. As is clear from Fig. 15, the tapered recesses 4, 4 of both skin layers 1, 1 of the sandwich structure are in complete contact with the tapered dents 87, 87 of the first engine-mounting metal member 83 in entire surfaces 4a, 4b. In this state, the tapered recesses 4, 4 and the tapered dents 87, 87 are fixedly bonded together by an adhesive. As shown in Fig. 15, since the holes 89 of the tapered dents 87, 87 of the side plates 86, 86 are aligned with the holes 5 of the bottom wall 4b of the tapered recesses 4, 4, they are fixed by bolts 86 extending therethrough. The engine is mounted to the first metal member 83 by inserting its ends into the holes 94, 94 of the second side plates 92, 92. A load of the engine is uniformly transmitted via both first side plates 86, 86 of the first engine-mounting metal member 83 to the tapered recesses 4, 4 of the two skin layers 1, 1 to which the first engine-mounting metal member 83 is fixed. Since the tapered recesses 4, 4 are fixed to the complimentarily tapered dents 87, 87, a load of any direction can always be sustained by some portions of the first engine-mounting structure having enough strength. Specifically speaking, when an upward load is applied, the load is sustained by the upper, conical side wall portions of the tapered recesses 4, 4. On the other hand, when a downward load is applied, the load is sustained by the surfaces 1a shown in Fig. 1 and 86a shown in Fig. 13. In general, a shear strength of adhesion is much larger than a peeling strength, the structure in which a load is sustained by this shearing strength is extremely advantageous in strength. Further, when a lateral load is applied, both lateral side wall portions of the tapered recesses 4, 4 sustain the load sufficiently. In addition, when a torsional load is applied, the torsional load can be sustained by the overall surfaces of the adhered walls of the tapered recesses 4, 4, because both overall tapered surfaces of the sandwich structure and the first engine-mounting metal member are fixed by adhesion. Moreover, since the tapered dents 87, 87 are fixed on both surfaces, a torsional load of any direction is transmitted as a pressing force to the tapered recesses in some portions on both surfaces. In other words, a force of peeling direction in a portion is inevitably a force in a pressing direction in another portion. Accordingly, the torsional load is sufficiently sustained by some of those portions. This means that a torsional load is not applied only as a peeling force to the bonded boundaries between the tapered recesses 4, 4 and the tapered dents 87, 87. As described above, a load exerted from the engine is fully sustained by the bonded portions between the tapered recesses 4, 4 of the skin layers 1, 1 and the tapered dents 87, 87 of the first engine-mounting metal member 83 and between the portion 1a in Fig. 1 and the portion 86a in Fig. 13. However, for the purposes of reinforcement and fail-safe, the first engine-mounting metal member is fixed to the first engine-mounting portion 78 of the sandwich structure by bolts 96, so that the first engine-mounting metal member is not detached even when the adhesion is broken. Bent fringe portion 91 of the bottom plate 90 of the first engine-mounting metal member 83 is for reinforcement of the bottom plate 90. The first engine-mounting structure according to the fourth embodiment of the present invention has been explained referring to the attached drawings, but the present invention is not restricted thereto, and any modifications can be made unless they deviate from the scope of the present invention as described above. Incidentally, the first engine-mounting metal member 83 shown in Fig. 12 has a pair of third side plates for mounting an upper arm, but the third side plates 93, 93 are not indispensable. As described above in detail, the first engine-mounting structure according to the fourth embodiment of the present invention can serve to uniformly transmit a load of the engine to the overall surfaces of the sandwich structure. Incidentally, the skin layers of the sandwich structure can be made of various plastics, and fiber-reinforced plastics are preferable. For formability, matrix materials of the fiber-reinforced plastics are preferably thermoplastic resins. Particularly, from the aspects of formability, strength and durability, carbon-reinforced nylons are preferable. The core layer may be formed plastics, honeycomb cores or even may be hollow. However, from the aspects of formability and strength, the foamed plastics, particularly polyurethane foams are preferable.

Claims: In a sandwich structure comprising a core layer (2) and plastics skin layers (1) formed on both surfaces of said core layer, a part-mounting portion (6) including a flat wall area (4b) formed by said skin layers bonded together, said flat wall area being at the bottom of a tapered recess (4) formed in at least one of said skin layers and having a sloping side wall (4a), said tapered recess being formed in the region of an edge of the sandwich structure with the recess being open toward the said edge, the sandwich structure having a flange portion (3) formed by the said skin layers bonded together along the said edge, and the said bottom wall of the tapered recess being coplanar with said flange portion. A vehicle body including a pair of part-mounting portions as claimed in claim 1, mounting a part which is a front suspension beam (30), the front suspension beam-mounting portions (18, 19) being formed in a lower edge portion of a front frame (20a) of the said sandwich structure at front and rear positions. A vehicle body as claimed in claim 2, wherein the rear mounting portion (19) is located at a higher position than the front mounting portion (18), said tapered recess (4) opening downward in said front mounting portion, and said tapered recess (4) opening downwardly and forwardly in said rear mounting portion. A vehicle body including a pair of part-mounting portions as claimed in claim 1, mounting a part which is an upper arm, said upper arm-mounting portions (48, 49) being formed in a lower edge portion of a vehicle frame (20a) of the said sandwich structure at front and rear positions. A vehicle body including a part-mounting portion as claimed in claim 1, wherein a said recess (4) is formed in each of said skin layers (1) and the said flat bottom wall (4b) has a hole (5) for mounting a part in the area in which said skin layers are directly bonded together. A part-mounting structure comprising a part-mounting portion (6) as claimed in claim 1 and a part-mounting metal member (7) having a bottom plate (8) and a pair of side plates (9) extending substantially perpendicularly from said bottom plate on both sides, at least one of said side plates having a dent (10) tapered complementarily to said tapered recess (4), and said part-mounting metal member being mounted to said part-mounting portion with a surface of said tapered recess and a surface of said tapered dent of said part-mounting metal member bonded together by an adhesive. A part-mounting structure as claimed in claim 6, wherein said part-mounting metal member (7) is further fixed to said part-mounting portion of said sandwich structure by a plurality of bolts extending through holes (15) of said part-mounting portion and said part-mounting metal member. A vehicle body including a pair of part-mounting structures as claimed in claim 6, mounting a part which is a front suspension beam (30), the front suspension beam-mounting structures (18, 19) being formed in a lower edge portion of a front frame (20a) of the vehicle body at front and rear positions. A vehicle body as claimed in claim 8, wherein said front suspension beam (30) is fixed to the bottom plate (9) of each front suspension beam-mounting metal member (7) by bolts in such a manner that an axis of said front suspension beam is substantially perpendicular to the bottom plate of said front suspension beam-mounting metal member mounted to the rear mounting portion of said sandwich structure. A vehicle body including a pair of part-mounting structures as claimed in claim 6, mounting a part which is an upper arm, the upper arm-mounting structures (48, 49) being formed in a lower edge portion of the vehicle body frame (20a) at front and rear positions, and the upper arm-mounting metal members (54) each having a pair of second side plates (63) extending from the other side of said bottom plate for supporting the upper arm. A vehicle body as claimed in claim 10, wherein said metal members (54) are further fixed to said upper arm-mounting portions (48, 49) by mechanical fastening means in portions where said tapered dents (56) of said metal members are bonded to said tapered recesses (4) of said upper arm-mounting portions. A vehicle body including a part-mounting structure as claimed in claim 6, mounting a part which is an engine, the said engine-mounting structure comprising an engine-mounting portion (78) of a vehicle body and a said metal member (83) for mounting the engine to said engine-mounting structure, and a pair of second side plates (92) extending from the other side of said bottom plate (90) for supporting the engine. A part-mounting structure as claimed in claim 12, wherein said metal member (83) is further fixed to said engine-mounting portion (78) by mechanical fastening means in a portion where said tapered dent (87) of said metal member is bonded to said tapered recess (4) of said engine-mounting structure.

Inventors: KAJIWARA HAJIME, KAWADE TATEO, OHNO MASAO, SANO SHOICHI, UCHIDA KEN, YOSHIDA SUGURU, KAJIWARA, HAJIME, KAWADE, TATEO, OHNO, MASAO, SANO, SHOICHI, UCHIDA, KEN, YOSHIDA, SUGURU
Applicants: HONDA MOTOR CO LTD, HONDA GIKEN KOGYO KABUSHIKI KAISHA
Application year: 1989
Main classification: B62D29
IPC codes: B62D29