FR2701899A1 - Rim and wheel for a cycle, and method for manufacturing them - Google Patents

Abstract

Rim and wheel for a cycle, characterised in that it consists of two annular elements joined together: a first element or outer element (2) made of plastic secured to a second element (3) or inner element made of a different material from that of the said first element.

Description

TENT AND WHEEL FOR A CYCLE AND THEIR MANUFACTURING METHOD
The present invention relates to a new rim for cycles. It also relates to the wheel comprising the rim, as well as its manufacturing process.

 The rims and in particular those intended for cycles are produced by a curved aluminum profile. In most cases, they are connected to the hub by spokes, in order to constitute the vehicle wheel. The profiles used are of different types, but generally have the shape of a U comprising two lateral wings whose outer faces constitute the braking faces against which the brake pads are pressurized to ensure the desired braking. This type of rim, although offering certain advantages, nevertheless presents a certain number of disadvantages. Indeed, the operation of bending the profile to give it its circular shape does not make it possible to ensure a rim width of precise and constant dimension over the entire circumference thereof. In addition, the operation of drilling the holes intended to receive the spokes nuts causes local swellings, thus creating an unpleasant irregular braking surface, and the braking efficiency is reduced accordingly. Furthermore, the rim being produced by bending a profile, inevitably comprises a connector at the junction of the two ends of the latter, a connector which, in most cases, is difficult to achieve perfectly, whether the junction is sleeved or welded. The passage of the fitting during braking causes jerks, further disrupting the braking qualities and accelerating the aging of the parts. In addition, wheels of this type are relatively heavy and do not have an aerodynamic profile. Also, some manufacturers have made wheels in composite material, but the sidewalls intended for braking also have irregularities detrimental to good braking, and it is not possible to produce a profile capable of receiving a tire, and these wheels do not can only be fitted with hoses. In addition, radial impacts on the edges of the rim quickly deteriorate the rim itself, which quickly becomes unusable.

 The present invention therefore seeks to remedy the drawbacks mentioned above and proposes a new rim and therefore wheel design.

 Thus the rim for cycle according to the invention is characterized in that it consists of two annular elements, integral with one another, namely, a first element or external element of plastic material, integral with a second element or internal element, made of a material different from that of said first element.

According to an additional characteristic, the first element is a circular profile having a section having the general shape of a
U open towards the outside, having two lateral wings connected by their base, by a transverse wall which comprises a projecting profile intended to cooperate with a hollow profile of the second element. Said projecting profile being for example formed by two converging lower faces of the transverse wall, while the corresponding hollow profile is formed by the two outer faces of the upper half-walls of the second element.

 According to another additional characteristic, the second element or internal element is in the general form of a circular box formed by a peripheral reinforcement wall covering a core, said peripheral wall being of composite material to constitute an external reinforcement wall around said core which is made of synthetic foam. Said core being for example made of hard foam, of the polyurethane type, while the reinforcing wall consists of one or more layers of glass or carbon fabric impregnated with epoxy type resin.

 The invention also relates to the method of manufacturing the rim which is characterized in that it comprises an additional step of machining the first rim element, while during a prior step, an initial annular profile is produced, the section has dimensions greater than the dimensions of the first element, said initial profile being intended to form said first element, and produced for example by injection of charged plastic material.

 The manufacturing process also includes another preliminary step, during which a synthetic foam core is produced which is covered with a layer of glass or carbon fibers to produce a covered core. Then in a preparatory stage, the initial profile is assembled with the covered core which is placed in a mold which is closed, before injecting resin into the layer or layers of fibers.

 Other characteristics and advantages of the invention will emerge from the description which follows with reference to the appended drawings which are given only by way of nonlimiting examples.

 Figures 1 to 5 illustrate a wheel with the rim according to the invention.

 Figure 1 is a plan view along the axis of the rim.

 Figure 2 is a side view of Figure 1.

 Figure 3 is a detailed sectional view along III-III on a larger scale showing the profile of the rim itself.

 FIG. 4 is a partial sectional view along IV-IV, on a larger scale, of FIG. 1.

 Figure 5 is a view similar to Figure 4, but in a section along V-V in Figure 1.

 Figures 6 to 20 illustrate the method of producing the rim.

 Figures 6 to 8 illustrate the initial circular profile of plastic material, produced in a prior step.

 Figure 6 is a plan view of this initial circular profile.

 Figure 7 is a side view.

 Figure 8 is a section on VIII-VIII of Figure 6.

 Figures 9a, 10a, 9b and 10b illustrate the foam half-cores, made in another prior step.

 Figure 9a is a plan view of one of the half-cores.

 Figure 9b is a plan view of the other of the half-cores.

 Figure 10a is a sectional view along Xa-Xa of the core of Figure 9a.

 Figure 10b is a sectional view along Xb-Xb of the core of Figure 9b.

 Figures 11 and 12 illustrate the two elements of the sleeve to be made beforehand, and intended to constitute the mechanical part of the hub.

 Figures 13, 14a and 14b show an intermediate step which consists in covering the outer face of two cores, with different reinforcing layers.

 Figure 13 is a perspective view illustrating the establishment of the different layers.

 Figures 14a and 14b are sectional views of the two covered half-cores.

 Figures 15 and 16 illustrate a preparatory step which consists in assembling the different elements of the wheel.

 Figure 17 illustrates the placement of the elements in an injection mold, while Figure 18 shows the mold in its closed injection position.

 Figures 19 and 20 are views similar to Figure 3, illustrating the last step of the manufacturing process. Figure 19 showing the rim before machining, while Figure 20 shows the rim after machining.

 The rim according to the invention and bearing the general reference (1) has a general plane of symmetry (P) and is constituted by two annular elements (2, 3): a first element or external circular element (2) integral with a second element or internal circular element (3).

The first element (2) is a crown constituted by a circular profile intended to retain the tire (not shown) from the wheel, and for this purpose, said profile has a section having the general shape of a
U open towards the external periphery (EX) and in which is intended to take place the tire and the possible inner tube. Said profile has two lateral wings (4 ', 4 ") advantageously symmetrical with respect to the plane (P), connected by their base, by a transverse wall (5).

Furthermore, the end of each of the wings comprises a peripheral projection, respectively (6, 7) extending towards the inside of the recess (8), intended to retain the tire fitted to the wheel. Note also that the outer faces (9, 10) of the side walls form the braking sides of the rim. Said transverse wall (5) is bounded on one side by a curved outer face (11) and on the other side, by an inner face (12) consisting of two lower converging faces (12a, 12b) which converge on the plane (P) of symmetry at a point (A).

 According to one arrangement of the invention, the first element or external circular element (2) is made of plastic and is for example made of polyamide loaded with short fibers of the carbon or glass fiber type.

 The second element of the rim or internal circular element (3) which is a structure, is in the form of a profiled circular box formed by a peripheral wall (13) covering a core (14). Said peripheral wall (13) is made of so-called composite material, to form one or more reinforcing layers which can be of all types, such as woven layers of glass or carbon fibers, impregnated with an epoxy resin. Furthermore, the core (14) is for example made of rigid foam of the polyurethane or polymethacrylate type.

The peripheral wall (13) comprises two curved side walls (15a, 15b) which are symmetrical and gradually converge towards the inside of the rim at a point (B) of convergence located on the plane (P). It also includes an upper wall (17) formed by two upper half-walls (17a, 17b) converging towards the inside of the core to form, by its external faces (17'a, 17'b), a shape complementary to the two faces. converging (12a, 12b) of the first element (2).

 It will also be noted that the core (14) consists of two half-cores (14a, 14b) arranged one against the other along the plane (P) and that the two upper half-walls are extended by two portions of vertical walls (18a, 18b) extending towards the inside of the core.

 The rim itself (1) and according to the preferred embodiment of the invention, is an integral part of the wheel and forms the assembly thereof, as appears more particularly in Figures 1, 4 and 5. Indeed, the rim itself said (1) is connected to the central part (19) of the wheel by three link arms (20a, 20b, 20c). As for the second element (3), the link arms and the central part are produced by the core (14, 14a, 14b) covered with one or more reinforcing layers of carbon fabric impregnated with resin.

 The process for manufacturing the wheel according to the invention, and in particular its rim, is described below and illustrated diagrammatically by FIGS. 4 to 20.

 According to this method, an initial circular profile (2i) intended to form the first element (2) of the rim is produced beforehand (FIGS. 6, 7, 8). This initial circular profile (2i) is for example produced by injection of a plastic material loaded with short fibers of the glass or carbon type or any other material. The shape of the initial profile has the shape of the initial section more particularly illustrated in FIG. 8. Thus, the initial profile is limited peripherally by two parallel lateral faces (21, 22), an upper face (23) and the two converging faces. lower (12a, 12b) converging at point (A) which form a circular "V" profile (120) projecting towards the axis (XX) and intended to cooperate with a hollow circular profile (170) of the second element ( 3).

 In another preliminary step (FIGS. 9a, 10a, 9b, 10b), the core (14) is produced by machining the two half-cores (14a, 14b) in a rigid polyurethane or polymethacrylate foam plate.

Each of the half-cores comprising a planar diametral face (140a, 140b) intended to be applied one against the other to be glued together.

 The wheel hub sleeve (24) is produced in another preliminary step, said sleeve being for example made of aluminum and obtained by machining. This comprises two lateral flanges (25, 26) nested and glued together in the assembly phase.

 In an intermediate step illustrated in FIGS. 13, 14a and 14b, the outer faces of the half-cores (14a, 14b) are covered with different pieces of carbon fabric (28, 29, 30a, 30b, 30c, 30d, 30e, 30f ). Said layers being glued to the core to facilitate handling of the covered half-cores (31a, 31b) thus produced, and as illustrated in FIGS. 14a and 14b.

 After having carried out the preliminary stages and the intermediate stage, a preparatory stage is carried out (FIGS. 15 and 16): the initial circular section (2i) is assembled with the two covered half-cores (31a, 31b) to produce a set of wheel (32) which is then placed in a mold (33) (FIG. 17) which is closed (FIG. 18), then resin is injected into the layers of carbon fabric to impregnate them and obtain, after heating and polymerization, on the one hand the rigidity of the reinforcing layers, and on the other hand, the bonding of the initial circular profile (2i) on the second element by adhesion of the converging faces (12a) and (12b) with the faces of the upper half-walls (17a, 17b). The retention of the element (2) on the second element (3) being of course also ensured by the cooperation of the projecting profile (120) and the corresponding hollow profile (170).

 After polymerization and removal of the wheel, in an additional step (Figures 19, 20), the initial circular profile (2i) is machined to give it its final shape. Figure 19 is a sectional view before machining, while Figure 20 is a view after machining. In this subsequent step, the flanks (9, 10) of the rim are formed on the one hand, and the circular recess (8) for retaining the tire on the other hand. The machining is done by removing material and in particular lateral material (210, 220) to produce diametrical faces (9, 10) of braking and central material (80).

 To this end, the dimensions (L, D) of the initial profile (2i) are greater than the dimensions (1, d) of the final circular profile (2) constituting the first element of the rim.

 Machining makes it possible on the one hand to obtain a precise dimensioning in width (1), and on the other hand to create perfect, homogeneous and continuous braking faces (20, 21), both in their dimensional aspect and in their surface finish appearance. Furthermore, the machining allows a perfect geometry of the profile (2) relative to the axis (XX ') of rotation of the wheel and of its plane (P) of general symmetry.

 The braking faces (20,21) are advantageously symmetrical with respect to the plane (P) and can be parallel to each other, but also convergent towards the axis of the wheel, as illustrated, to form for example an angle of about 3 degrees with the plane (P), but they can be just as divergent.

 Of course, the invention is not limited to the embodiments described and shown by way of examples, but it also includes all the technical equivalents and their combinations.

Claims (11)

 1. Rim for cycle, characterized in that it is constituted by two annular elements, integral: a first element or external element (2) made of plastic, integral with a second element (3) or internal element, produced in a material different from that of said first element.  2. Rim for cycle according to claim 1, characterized in that the first element (2) is a circular profile having a section having the general shape of a U open towards the outside, having two lateral wings (4 ', 4 ") connected by their base, by a transverse wall (5) which comprises a projecting profile (120) intended to cooperate with a hollow profile (170) of the second element (3).  3. Rim for cycle according to claim 2, characterized in that the projecting profile (120) is formed by two lower faces (la, 12b) converging on the transverse wall (5), while the hollow profile (170) corresponding is formed by the two outer faces (17'a, 17'b) of the upper half-walls (17a, 17b) of the second element (3).  4. Rim for cycle according to claim 3, characterized in that the second element (3) or internal element is in the general form of a circular box formed by a peripheral reinforcement wall (13) covering a core (14) , said peripheral wall (13) being made of composite material to constitute an outer reinforcing wall around said core (14) which is made of synthetic foam.  5. A rim for a cycle according to claim 4, characterized in that the core is of hard foam, of the polyurethane type, while the reinforcement wall (13) consists of one or more layers of glass or carbon fabric impregnated with epoxy resin.  6. Wheel fitted with the rim according to any one of the preceding claims, characterized in that it comprises link arms (20a, 20b, 20c) connecting said rim (1) to a central part (19).  7. A method of manufacturing a rim for cycle according to any one of the preceding claims, characterized in that it comprises a complementary step of machining the first rim element (2).  8. Manufacturing method according to claim 7, characterized in that in a prior step, an initial section (2i) is annular, the section of which has dimensions (D, L) greater than the dimensions (d, 1) of the first element (2), said initial section (2i) being intended to form said first element (2).  9. The manufacturing method according to claim 8, characterized in that the prior step is an injection of charged plastic material.  10. The manufacturing method according to claim 8 or 9, characterized in that in another preliminary step, a core (14) is made of synthetic foam which is covered with a layer of glass or carbon fibers (28, 30a, 30b, 30c, 30d, 30e, 30f, 29) to make a covered core (31a, 31b).  11. The manufacturing method according to claim 10, characterized in that in a preparatory step, the initial section (2i) is assembled with the covered core (31a, 31b) which is placed in a mold (33) that the it is closed, before injecting resin into the fiber layer (s) (28, 30a, 30b, 30c, 30d, 30e, 30f, 29).