FR2771699A1 - Frame for motor vehicle - Google Patents

Abstract

The leading frame section (3) extends from the front of the vehicle body by a predetermined extent. Towards the rear, a section of the rear frame (5) is located under the seat (6). These frames are joined by an intermediate section (4). Preferred features: Front and rear frame sections are made in fibre reinforced plastic, the rear frame taking the form of a parcel compartment. The front frame has an integral non-slip panel. This frame is a U-shaped molded shell, with transverse open structure at one end. Here a welded on, flat transverse panel of reinforcement forms a closed structure. A number of stiffening ridges rise from the base of the molded shell to be welded to this panel. The rear frame shaped as a compartment, has jointing regions below it, and is fixed to the intermediate section. To the rear of the compartment is a fastening point for a rear shock absorber. This is mounted onto the compartment via a panel contacting the rear wall of the compartment, with the lower surface of a wall projecting towards the rear of the latter. A seat is placed on the compartment, pivoting to it on a hinge axis incorporated in a transverse opening formed in a reinforcement of the compartment. The frame sections are formed by moulding in fluid state, commencing with a sheet comprising layered reinforcing filaments with intervening thermoplastic.

Description

 The present invention relates to a frame-frame for motorcycles or the like such as two-wheeled or three-wheeled vehicles of the scooter type, for example, and more particularly to a frame-frame technology which easily meets the demand for diversification of motorcycle designs while simplifying construction, improving manufacturing technique and reducing weight.

 Until now, as a frame-frame intended for two-wheeled vehicles of the scooter type, for example, a frame-frame of integral structure has been known, consisting mainly of an aluminum frame. In the case of motorcycles of the scooter type or the like, as a part of the frame serves as a footrest located near the ground, a separate non-slip plate is disposed on the aluminum frame mentioned above so as to protect the articles or the like transported on the frame, when the vehicle hits a curb or the like, for example. On the other hand, in order to reduce the weight of the vehicle, it was known to use a synthetic resin reinforced with fibers to form the frame of the vehicle. One of these known synthetic resin frames has a two-piece design, including a front frame portion, which is tilted back and down from a fork tube and which then extends horizontally at the bottom thereof, as well as a rear frame element produced generally in the form of a luggage compartment, which is fixed to a rear end of the front frame element.

 With regard to the known synthetic resin frame-frame, however, when the size of a vehicle is modified in the longitudinal direction thereof due to a request for diversification of the models of motorcycles, namely the front frame element, either the rear frame element must be re-prepared or re-manufactured, thereby increasing the production cost. In addition, in the case of an aluminum frame, the mounting of a non-slip plate on the part forming the footrest will lead to an increase in the number of constituent elements, and the need for an assembly operation.

 In addition, the technology according to which a chassis frame is made of fiber-reinforced synthetic resin has been described, for example, in Japanese patent publication NO H06-184322. In this prior art, so as to form a floor and a rear frame element of the chassisframe so that it is in the form of a monocoque structure closed in cross section, a pair of molded shells of generally shaped configuration is produced. of U, each of which has a pair of flanges projecting transversely out of the open end thereof. The respective flanges of one of the molded shells are fixed in opposition relation to the corresponding flanges of the other by means of fixing screws or the like, so as to form a closed structure in cross section. The connected edges serve as footrests. However, when the opposite edges protruding transversely on the open end of the molded shells are produced, the molding dies intended to form the shells become of a complex configuration, and much time is necessary for the fixing operation. ledges using screws or the like.

 An object of the present invention is therefore to provide a frame-frame of simple design, which allows to modify or vary easily and inexpensively the dimension in the longitudinal direction, the shape of the vehicle, or the like.

 Another object of the present invention is to provide a fiber reinforced synthetic resin frame which has high structural rigidity and which is easy to form using molding dies or the like.

 With a view to achieving the aim described above, a frame-frame according to the present invention comprises a front frame element extending from the front of the body of a vehicle over a predetermined extent in the direction of the rear, a rear frame member disposed under a seat, and an intermediate frame member adapted to connect the front frame member to the rear frame member. Thanks to the use of the intermediate frame element through which the front and rear frame elements are connected, the dimensions, shapes or the like of the vehicle can be varied by simply modifying the intermediate frame. Furthermore, since the front frame member and the rear frame member can be used in common for a plurality of vehicle models, it is possible to reduce the production cost and simplify maintenance or the like due to the use of building blocks. On the other hand, if one prepares a plurality of front frame elements and rear frame elements which are of material, shape and size or the like, which differ, one can use in combinations that suitably vary with the middle frame element to accommodate a variety of designs.

 Preferably, at least each of the front frame member and the rear frame member of the chassis frame is formed of fiber-reinforced synthetic resin, and the rear frame member is made primarily in the form of a luggage compartment. Thus, the front and rear frame elements which constitute the main part of the frame-frame are formed from fiber-reinforced synthetic resin, thereby contributing to a reduction in the weight of the vehicle. Here, the synthetic resin materials incorporating fiber reinforcement means may include thermoplastic synthetic resins or thermosetting synthetic resins, and the reinforcement means may be in the form of glass fibers, carbon fibers, fiber fibers ceramic, aramid fibers or other.

 The front frame element has an integrated non-slip plate. The realization of the non-slip plate in one piece with the front frame element makes it possible to obtain a reduction in the number of constituent elements, and avoids an assembly operation.

When the front frame member is made of fiber-reinforced synthetic resin, the non-slip plate can easily be molded in one piece with it without requiring additional time.

The front frame member is composed of a substantially U-shaped molded shell, of open cross-sectional structure, at an open end from which a flat reinforcing member is welded so as to form a closed cross-sectional structure. A plurality of stiffening ribs extend upward from the bottom of the molded shell to be welded to the flat reinforcing member. Such a U-shaped molded shell and such a flat reinforcement element can easily be produced using molding dies and, by welding the reinforcement element at the open end of the molded shell.
In order to form the structure with a closed cross section, it is possible to obtain a chassis frame of high rigidity. The molded shell provided with an open end can be made in a U-shaped or semi-circular configuration or the like in cross section, which facilitates the removal of the molded shell from the molding die. The reinforcing element has practically the same width as the open end of the molded shell, so that it barely protrudes outside the molded shell. As a welding method between the molded shell and the reinforcing element, a heat-sealing method can be adopted in which the joint regions between them are heated and welded to each other, a welding method by vibration in which microvibration is applied to the joint regions, while they are kept under pressure, in order to weld them thereby by heating due to friction, a high frequency welding process in which the joint regions are welded together by high frequency induction heating, and the like. By using the closed cross-sectional structure obtained by welding the reinforcing member to the open end of the molded shell, it is possible to strengthen the torsional rigidity, the flexural rigidity or the like while reducing the weight of the vehicle, and it is possible to prevent the open end of the molded shell from widening so as to maintain dimensional accuracy. When covered and closed by the reinforcing element, the U-shaped molded shell is transformed into a structure with a practically square cross section, so that it can be provided with a higher torsional rigidity in comparison of a semi-circular cross section. The stiffening ribs are arranged inside the U-shaped shell and are welded to the reinforcing element.

They are preferable in order to further strengthen the torsional rigidity and the flexural rigidity of the chassis frame.

 The rear frame element, in the form of a luggage compartment, is provided at the bottom of the luggage compartment with a plurality of fixing regions intended to fix the rear frame element to the intermediate frame. By fixing the intermediate frame element to the luggage compartment which constitutes the main part of the rear frame element, it is not necessary to enlarge or extend the intermediate frame element towards the rear, d where it results in a reduction in weight. The luggage compartment is provided, at its rear region, with a fixing part intended for a rear suspension element. The rear suspension element is mounted on the luggage compartment by means of a lug which is arranged in contact with a rear wall of the luggage compartment, and with a lower face of a wall projecting towards the rear of that -this.

Through the use of the intermediate frame member in the manner mentioned above, the force transmitted from the rear suspension member is widely distributed, and the upwardly directed force is supported by the wall protruding towards the rear so as to prevent a concentration of stresses on the bolts or the like arranged on the rear wall of the luggage compartment.

 A seat arranged on the luggage compartment is pivotally supported by a hinge pin which is inserted through a through hole formed in a flange of the luggage compartment. The through hole is formed by communicating transversely each of the concave parts of given width and given depth which are arranged alternately in upward and downward orientations.

That is to say that the concave parts are formed alternately in such a way that each of the concave parts upwards and downwards has a bottom of the same depth dug from opposite directions alternately which extends in a same transverse axis, respectively, and that neighboring alternating concave parts, of the same width, define lateral cutting surfaces, each of which extends in the same vertical plane. Such alternating concave parts are placed in transverse communication with each other so as to form the through hole intended for the hinge axis.

By virtue of the formation of the concave parts and the through hole as mentioned above, the hinge structure can be achieved easily using simple equipment, without the use of slide dies or the like.

 According to a further aspect of the present invention, each of the front and rear frame elements of fiber-reinforced synthetic resin is formed, by a fluidized molding process, of a laminated sheet in which a fiber mat is laminated. made of filaments and a synthetic thermoplastic resin. The process for molding in the fluidized state which is mentioned here comprises the steps consisting in obtaining a predetermined volume of rough material by cutting out a laminated sheet in which are laminated in multiple layers mats of continuous fibers or filaments and sheets of thermoplastic synthetic resin or the like, heating the blank material to a temperature above the melting point of the synthetic resin, and stamping the molten blank material while fluidizing the synthetic resin therein a molding die. Thanks to the application of this molding process in the fluidized state, the forming cycle can be shortened so as to improve productivity, and the rigidity of the frame-frame can be increased, at equivalent weight, until it reaches approximately double the Izod resilience, for example, compared to a sheet molded composite product which is obtained by stamping a thermosetting synthetic resin reinforced with glass of cut fibers or the like. The mat of continuous fibers or filaments to be used may be formed of glass fibers, carbon fibers or other fibers in the form of continuous filaments, and the thermoplastic synthetic resin to be used may be a polypropylene plastic or analogues.

The present invention will be more clearly understood by reference to the following detailed description of preferred embodiments when read in conjunction with the accompanying drawings, in which identical reference characters refer to identical parts in all of the views, and in which
Figure 1 is a side elevational view of a two-wheeled motorcycle in the form of a scooter to which the present invention is applied.

 Figure 2 is an exploded perspective view of a frame-frame.

 Figure 3 is a side view of a front frame member for explaining a state of connection between a front frame member and an intermediate frame member.

 FIG. 4 is a plan view of the front frame element shown in FIG. 3.

 Figure 5 is a sectional view of Figure 3, taken along the line A-A.

 Figure 6 shows sectional views showing different types of welded states between a U-shaped molded shell and a flat reinforcing element.

 Figure 7 is a side elevational view showing a rear part of the chassis frame constituting mainly a luggage compartment.

 Figure 8 is a top plan view of the luggage compartment.

 Figure 9 is a view for explaining the state of connection between the intermediate frame member and a rear frame member.

 Figure 10 is a view for explaining a state of attachment of a rear shock absorber to the luggage compartment.

 Figure 11 is an exploded perspective view showing an attachment region of the rear shock absorber.

 Figure 12 is an explanatory perspective view showing a seat hinge structure formed on a flange of the luggage compartment.

 FIG. 13 is a plan view from above of the flange of FIG. 12.

Figure 14 is a sectional view taken along the line
AA of figure 13, and
Figure 15 is a sectional view taken along the line
BB of figure 13.

 The embodiment of the present invention will now be explained with reference to the accompanying drawings. Referring first to Figure 1, a frame-frame according to the present invention is applied for example to a frame-frame 2 of a two-wheeled motorcycle 1 of the scooter type. As shown in FIG. 2, this frame-frame 2 comprises a front frame element 3, an intermediate frame element 4 and a rear frame element 5. The rear frame element 5 mainly comprises a luggage compartment. On the rear frame element 5 is mounted a seat 6 (Figure 1). These front frame member 3, intermediate frame member 4 and rear frame member 5 are made of fiber-reinforced synthetic resin respectively. In this embodiment, these frame elements are formed, by a process of molding in the fluidized state, of a laminated sheet in which are laminated a thermoplastic polypropylene resin and a glass fiber in filaments. In order to manufacture the frame-frame in accordance with this process of molding in the fluidized state, there is provided a needled mat of approximately 40% by weight, which is obtained by needling beforehand a glass fiber in the form of continuous filaments, and a Polypropylene of approximately 60% by weight to which a heat resistance treatment and a weather resistance treatment are applied beforehand. The needled mat and polypropylene are first laminated into multiple layers to form a laminated sheet. A predetermined volume of blank material is obtained by cutting the laminated sheet, and is heated to temperatures between approximately 200 and 220 degrees centigrade thereby softening or melting the polypropylene to bring it to the fluid state. Then, the heated blank material is transported into a molding die so as to be stamped, when the die is quickly closed, to form each of the frame members. Thanks to this molding process in the fluidized state, the molded products can be filled with fibers in a very dense manner, thereby increasing the rigidity, at equivalent weight, compared to composite sheet molded products, and it is possible to even perform effective molding.

 The front frame member 3, as shown in Figure 3, is integrally provided with a fork tube support part 3a and a footrest part 3c. An upright portion extending vertically 3b, for which bending rigidity and torsional rigidity are required, is produced in a closed cross-section structure, by welding a flat protective plate 8 to a molded shell 7 having a cross section open, thus obtaining sufficient rigidity. The molded shell 7 is in the form of an integrated structure comprising, along its length, the fork tube support part 3a, the upright part 3b and the footrest part 3c. With the exception of the support part of the fork tube 3a, the molded shell 7 has a substantially U-shaped cross section and is open upwards. As shown in Figures 3 and 4, on the inner wall of the U-shaped cross section are provided a plurality of ribs extending transversely 7r intended to strengthen the rigidity.

 In the case of molding of the front frame element 3, the molded shell 7 of open cross section is firstly produced using the forming die during the molding process in the fluidized state. Although the molded shell 7 is made in one piece over its entire length, it is easily removed from the matrix because the basic configuration has a U-shaped configuration with an open upper end, and because the transverse ribs 7r extend from the bottom of the U-shaped shell to the open end of the molded shell 7 in the upward direction. Then, the flat protective plate 8 is molded using another matrix by a molding process in the fluidized state, so as to have a shape which can cover the open end of the upright part 3b. Thus, the flat protective plate 8 is welded to the open end of the molded shell 7 so as to form a closed cross section. During welding, a filament 9 as a high-frequency inductor is embedded in the seal region of the flat cover plate 8, as shown in Figure 5. The seal region is heated and melted inside 'a high frequency electric field, thus being welded while embedding the filament 9. The filament 9 can be embedded on the side of the molded shell 7, as shown in Figure 6 (A). Alternatively, welding can be accomplished by vibration welding in which microwave vibration is applied to the joint region while the molded shell 7 and the flat shield 8 are pressed against each other, as shown in Figure 6 (B). By fully welding the upright portion 3b of the front frame member 3 as mentioned above, it is possible to increase the torsional rigidity and the flexural rigidity while obtaining a reduction in weight. Although a slope is formed on each of the opposite side walls of the U-shaped shell 7 to facilitate exit from the die, the width between the opposite side walls is kept constant by welding the flat plate 8 to the molded shell 7, thereby improving the accuracy of the dimensions.

 The bottom wall of the molded shell 7 in which the footrest part 3c is located also serves as a non-slip plate. As this molded shell 7 is produced according to a U-shaped structure open upwards, it is not necessary to provide any additional non-slip plate or the like on the bottom thereof.

 The intermediate frame element 4 is provided with a seal wall 4f intended to be fixed to the front frame element 3, and a seal region 4r intended to be fixed to the rear frame element 5, and the attachments can be made, for example, using fixing bolts, by means of necessary stiffening means such as metal plates or the like. That is to say that the front frame element 3 and the intermediate frame element 4 are fixed in the manner shown in FIG. 2. For the intermediate frame element 4, several types of variants, each of which is different in length, inclination or the like, so that different types of vehicle frames with regard to length, shape or the like can be constructed for more than one model of motorcycle, by changing the type of the intermediate frame member 4 while using the common front frame member 3 and the common rear frame member 5.

 The rear frame element 5 is produced mainly in the form of a luggage box and, as shown in FIG. 7, it is fixed to the intermediate frame element 4 by fixing a bottom wall of the luggage box to the joint region 4r of the intermediate frame element 4 by means of fixing bolts. As shown in Figures 7 and 8, on the bottom of the luggage compartment of the rear frame member 5 are provided two parallel grooves extending transversely M, M, on the opposite ends of which are formed holes for bolts allowing '' insert shoulder bolts b, b through them. On the other hand, on the intermediate frame element 4 is provided a mounting plate 16 of metal or synthetic resin, as shown in Figure 9, which has two pairs of nuts n, n corresponding to the bolt holes of the luggage compartment. When fixing the rear frame element to the intermediate frame element 4, the shoulder bolts b, b are inserted from the bottom of the luggage compartment, through the holes for bolts, in the nuts n, n of the mounting plate 16, so as to fixedly attach the rear frame element 5 against the intermediate frame element 4. There is no provision in this exemplary embodiment, but it is possible to provide a metal stiffening plate or the like, which is placed on each of the grooves M, M of the luggage compartment and extends over the entire length thereof, so that a more stable fixing using the bolts b, b can be obtained between the intermediate frame element 4 and the rear frame element 5. Due to the fixing using the bottom wall of the luggage compartment, it is not necessary that the middle frame 4 way its rear end extend e excessively rearward, which contributes to a saving in material cost and a reduction in the weight of the vehicle or the like.

 With regard to the frame-frame 2 as it is constructed according to the method mentioned above, when the front frame element 3 and the rear frame element 5 are used in common for all the models of motorcycles and that the intermediate frame member 4 is changed according to the models, it is possible to obtain different types of frame-frame for respective motorcycle models, whereby the production cost can be reduced, and maintenance of the vehicle or the like can easily be performed. Furthermore, as regards the front frame element 3, the bottom wall of the footrest part 3c serves as a non-slip plate, and does not require any additional non-slip plate, which makes it possible to reduce the weight of the vehicle and the material cost.

 A rear shock absorber 10, which extends upwards from a swinging arm, is mounted by means of a metal frame lug 11 on the upper rear end of the luggage compartment of the frame element rear 5. That is to say that on the upper rear end of the luggage compartment is provided a projecting region r. The frame lug 11 is mounted via a plurality of fixing bolts 12, 12 on the rear end of the luggage compartment so that it is in contact, via the upper wall of the latter, with the underside of the projecting region r as well as in contact, via the rear wall thereof, with the rear surface of the luggage compartment. The upper end of the rear shock absorber 10 is mounted on the frame tab 11 using a fixing bolt 13. With this design, an upwardly directed force transmitted from the rear shock absorber 10 is distributed to the plurality of fixing bolts 12, 12 and the force coming from the ground is supported by the region projecting towards the rear r of the luggage compartment, thereby preventing the fixing bolts 12, 12 from being concentrated of constraint.

 On a flange f of the upper front end of the luggage compartment is provided a hinge connection region intended for a driver's seat which covers the upward opening of the luggage compartment. As shown in FIG. 12, on the flange f, four semi-circular concave parts c, c of a given depth and a given width are alternately dug from the top and the bottom and are placed in transverse communication with the one with the other so as to form a through hole s intended for a hinge pin 14. That is to say that, as shown in FIGS. 13 to 15, the flange f has a given thickness and a given width so to protrude from the front over a given area.

The semi-circular concave parts c, c are formed alternately on the flange f in such a way that each of the concave parts upwards and downwards c, c has a bottom of the same depth dug from opposite directions alternately, the bottom of which extends or lies on the same transverse axis, respectively, and which adjacent alternating concave parts c, c, of practically the same width, define lateral cutting surfaces which extend on the same vertical plane. The alternating concave parts are in communication via their bottom with one another so as to form the through hole s of circular shape. Due to the formation of the concave parts c, c and the through hole s as mentioned above, the hinge structure can be easily achieved without the use of slide dies or the like, thus making the design of the manufacturing equipment.

 As shown in FIG. 12, the hinge pin 14 is inserted from a hinge bore 6a of the seat 6, through the through hole s, into a nut 15.

When the hinge pin 14 is fixed to the nut 15, the seat 6 is supported with the possibility of pivoting by the hinge pin 14 on the flange f.

 Although a preferred embodiment of the present invention has been presented and described in detail, the invention is not limited to this but can also be produced in various ways, and a frame-frame 2 having practically the same design and fulfilling the same function to achieve the same result will fall within the same technical scope as the claimed invention. For example, the design of the seal between the front frame element 3 and the intermediate frame element 4 as well as the design of the seal between the intermediate frame element 4 and the rear frame element 5 can be freely chosen, and the intermediate frame member 4 can be made of a metallic material such as aluminum or the like instead of synthetic resin.

Claims (8)

 1. Frame-frame (2) for motorcycles or the like, comprising a front frame element (3) extending from the front of a vehicle body over a predetermined extent towards the rear, a frame element rear (5) disposed under a seat (6), and an intermediate frame member (4) adapted to connect said front frame member to said rear frame member.  2. Frame frame (2) for motorcycles or the like according to claim 1, wherein at least each of said front frame member (3) and said rear frame member (5) is made of fiber-reinforced synthetic resin, and said rear frame element is produced mainly in the form of a luggage compartment.  3. Frame-frame (2) for motorcycles or the like according to either claim 1 or claim 2, wherein said front frame element (3) is integrally provided with a non-slip plate.  4. Frame-frame (2) for motorcycles or the like according to any one of claims 1 to 3, in which said front frame element (3) is produced in the form of a molded shell practically in the shape of a U (7 ), of open cross-sectional structure, at an open end from which a flat reinforcing member (8) is welded to form a closed cross-sectional structure, and a plurality of stiffening ribs (7r) extend upward from the bottom of said molded shell (7) so as to be welded to said flat reinforcing element.  5. Frame-frame (2) for motorcycles or the like according to any one of claims 2 to 4, in which said rear frame element (5) made in the form of a luggage compartment is provided, at the bottom of the compartment to luggage, of a plurality of joint regions for attachment to said intermediate frame member (4).  6. Frame-frame (2) for motorcycles or the like according to any one of claims 2 to 5, in which the luggage compartment is provided on its rear region with a fixing part intended for a rear shock absorber (10), and said rear shock absorber is mounted on the luggage compartment by means of a lug (11) which is arranged in contact with a rear wall of the luggage compartment and with a lower surface of a wall projecting towards the rear of it.  7. Frame-frame (2) for motorcycles or the like according to any one of claims 2 to 6, in which a seat (6) is disposed on the luggage compartment, and is supported with possibility of pivoting by a hinge pin. (14) which is inserted into a through hole formed in a flange of the luggage compartment, and said through hole is made by making transverse communication each of concave parts of given width and given depth which are arranged alternately in the upward direction and bottom.  8. Frame-frame (2) for motorcycles or the like according to any one of the preceding claims, in which each of said front and rear frame elements of fiber-reinforced synthetic resin is produced by a fluidized molding process. , from a laminated sheet in which are laminated a mat of filament fibers and a thermoplastic synthetic resin.