FR2666544A1 - RESIN WHEEL. - Google Patents

Abstract

Resin wheel (11) having two or more independently molded parts (11A and 11B) one of which is screwed into the other molded part or the other molded parts, so that the molded parts are fitted and coupled together. The wheel (11) includes a rim (1), a disc (2) and a hub bolt hole (3). Such a wheel can be used in the automotive field.

Description

RESIN WHEEL

FIELD OF THE INVENTION

  The present invention relates to a resin wheel, and more particularly, to a low-weight resin wheel which is suitable for mass production and excellent in mechanical characteristics such as impact resistance, bending resistance, stiffness, heat resistance, strength

  fatigue and creep resistance.

BACKGROUND OF THE INVENTION

Among the wheels, the auto wheels

  mobiles are usually made of steel or

  light alloys such as aluminum alloys

  minium and magnesium alloys.

  Steel wheels are manufactured by compression or forming of profiles The formed wheels vary greatly in terms of the dimensions provided. Specially, the roundness of the heel seat

  of the rim often deviates from the desired value.

  In addition, steel wheels are heavy and therefore are not desirable since all parts of the automobile tend to

be reduced in weight.

  On the contrary, the wheels made of alloy

  lightweight are formed with stable dimensions.

  In addition, these wheels are much lighter than steel wheels. Namely, the weight of light alloy wheels is a third of that of steel wheels. However, the materials of light alloy wheels cost three to five times more than steel wheel materials so the

  light alloy wheels are very expensive.

  In recent years, the focus has been on saving energy To obtain this saving, it is quite important to reduce the weights of parts of the automobile. Specially, the unsprung elements such as the wheels to be manufactured with lighter weight to improve economy

fuel and handling.

  Under these circumstances, a resin wheel which is satisfactorily of low weight, which can be molded stably, and which

  is economical to manufacture has been proposed recently.

  This resin wheel mainly contains a fiber reinforced plastic, i.e. a resin reinforced with short and long fibers The resin wheel is lighter and molded with greater stability than the metal wheel In addition, the resin wheels are

  suitable for mass production In cons-

  As a result, manufacturing costs can be reduced. In addition, the resin wheel is expected to have excellent capacity for coloring and other design factors. Such resin wheel is required for have the following characteristics: (1) It is highly impact resistant

to avoid destruction.

  (2) It only flows slightly, for

  avoid the tire coming off the wheel.

  (3) It is highly resistant to

  heat produced by the brake drum.

  (4) It is excellent in uniformity.

  Since the wheel is an important part of the automobile, if the molded wheel is not uniform or if it has a defect, the wheel cannot be used.

  (5) It can be produced in large series.

  The upper half of the wheel of the prior art is shown in Figure 4 The wheel includes a rim 1 and a disc 2 provided with a hole 3

  for hub bolt Aluminum wheels available

  commercially available are roughly classified in terms of construction in two categories (1) one-piece wheel which is produced by molding the rim and the disc together; and (2) two-piece wheel which is made by molding the rim 1: and the disc 2 separately and then by assembling them with metal bolts The two-piece wheel has the great advantage that various combinations of wheels can be offered by changing the

  drawing of disc 2 while maintaining the construction

  rim 1 However, the two-piece wheel must have overlapping parts, since

  rim 1 and disc 2 are joined together.

  In addition, the two-piece wheel is heavier than the one-piece wheel, since the overlapping parts are joined together with

metal bolts.

  Of course, the low weight of the resin wheel is its first selling point To exploit this quality, any construction that

  increasing weight should be avoided as much as possible.

  Consequently, the present situation is that the resin wheel of the prior art takes the form of a one-piece wheel, whether it is manufactured by injection molding or compression molding. If the prior art resin wheel is made by compression molding,

  the fibers are relatively slightly loose

  improved at the time of molding As a result, the molded wheel is excellent in rigidity, strength and other factors In addition, the molded wheel has good heat resistance and good creep resistance, since the resin used most often comprises a resin thermosetting However, this molding method is not suitable for molding of complex shape such as a wheel whose wall thickness varies greatly from one area to another In addition, the productivity is low, since the cycle

molding is long.

  On the contrary, the process of molding by

  injection is quite excellent in production

  activity and reduces manufacturing costs.

  However, the resistances of products produced by injection molding generally vary from a third to a fifth of the resistances of the products

  manufactured using compression molding.

  Specifically, when the resins are kneaded or flow, the fibers are deteriorated or flow. Then, the fibers and the molecules are oriented, or a flow line is created at the point where the two masses of resin meet. it follows that the physical properties of the material of the molded product become non-uniform or deteriorate, leading to reductions in strength. Specially, in the case of a wheel, casting lines often take place, partly because the disc is provided with many decorative holes to increase the cooling effect and for aesthetic reasons and partly because bolt holes exist for assembly to the drum of the automobile body Because of the frequent presence of a casting line , resin wheels have not yet been made by injection molding in practice, and resin wheels made by injection molding have not

been placed on the market.

SUMMARY OF THE INVENTION

  In view of the above problems with the wheels of the prior art, it is an object of the present invention to provide a resin wheel which is excellent in its mechanical characteristics such as impact resistance, fatigue resistance, and resistance to creep, which is economical to manufacture, and which can be produced

in large series.

  It is a more specific object of the invention than to provide a resin wheel which is of

  low weight and excellent resistance, special-

  Also in characteristics such as flexural strength, impact resistance, rigidity, heat resistance, resistance to

fatigue, and resistance to creep.

  It is another object of the invention to provide a resin wheel which has uniform physical properties and varies little in quality.

  among the commercial products produced.

  It is an additional object of the invention to provide a resin wheel which is suitable for mass production

  and which can be manufactured at low cost.

  It is yet another object of the invention to provide a resin wheel which is divided into two or more parts, so that

  various types can be constructed.

  The resin wheel according to the invention comprises two or more molded parts coupled together. The individual parts are molded separately, and then one of them is screwed into the other or the others, so that they are adjusted. together More specifically, two independent parts are rotated by a given angle in opposite directions so that the convex parts can be adjusted in the concave parts. For example, these two

  parts are a bolt and a nut.

  The new resin wheel has two or more molded parts which are adjusted together by screwing the convex parts into the concave parts, but the weight of the wheel is not thereby greatly increased This wheel

  is also not less than a one-wheel

  part at the resistance level In addition, this wheel

  resin type separate parts suf- guard

  fisam-ment the advantages of two-piece wheels so that lower costs and greater

  design freedom be provided.

  Other objects and characteristics of the invention will become apparent during its

description which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

  F Igures 1, 2 A, 2 B, 3 are views

  in cross section of resin wheels according to the invention.

  Figure 4 is a sectional view of a resin wheel of the prior art. Figures 5 A, 5 B, 6 A and 6 B are front elevations of the fitting parts of the resin wheels shown in Figures 2 A and 2 B; Figure 7 is a sectioned perspective view of an example of a pair of fitting parts; Figures 8 A, 8 B and 8 C are sectional views of other examples of a pair of fitting parts; Figure 9A is a cutaway perspective view of another example of a pair of fitting parts; Figure 9 B is a sectional view along the plane B-B of Figure 9 A; Figure 10 is a sectional view of a further example of a pair of fitting parts; Figures l HA, IIB, IIC, Il D, IE, 11 F are enlarged sections of the adjusting parts, to show the shapes of the threaded parts; Figure 12 is still a sectional view of another resin wheel according to the invention; Figure 13A is still a sectional view of the vicinity of the hub of an additional resin wheel according to the invention; Figure 13 B is an enlarged view of part B of Figure 13 A; Figure 13 C is a sectional view along the plane C-C of Figure 13 B; and Figure 14 is a sectional view

  an additional resin wheel according to the invention.

  DETAILED DESCRIPTION OF THE INVENTION

  Referring to Figures 1,2 A, 2 B, and 3,

  resin wheels according to the invention are shown.

  Note that Figures 2 A and 3 are

  cuts of the upper halves of resin wheels.

  In these figures and in the following, a rim is designated by the number 1 The number 2 designates a disc A hole for the bolt of the hub 3 is

formed in disc 2.

  Each of these resin wheels according to the invention is divided into a plurality of parts No limitation is imposed on the number of numerous parts No restriction is given either on the position or positions

wheel divisions.

  In Figure 1, the resin wheel is generally indicated by the number 11 This wheel It is divided into two parts, namely, the parts

  shown IA and IIB, at rim 1.

  In Figure 2 A, the resin wheel is generally indicated by the number 12 This wheel 12 is divided into several molded parts 12 A,

  12 B, 12 C and 12 D, at disc level.

  In Figure 2B, the resin wheel is generally indicated by the number 120. This wheel 120 is divided into molded parts 121, 122, etc. In Figure 3, the resin wheel is generally indicated by the number 13 This wheel 13 is divided into molded parts 13 A, 13 B, 13 C, 13 D and 13 E at the rim 1 and at

disc level 2.

  In Figures 1, 2 A, 2 B and 3, each

  part of the division is molded independently.

  These molded parts have parts which fit 91, 92, 93, 94, 95, 96, 97, 98 and 99 screwed one

in the other.

  The separate part 121 of the wheel 120 forms the rim 1 and the outer periphery of the hub 2 A plurality of notches 122 is formed in the internal surface of the separate part 121 This internal surface 123 is threaded at the

  periphery except at the positions of the notches 122.

  The separate part 123 forms the central part of the hub 2, and comprises a radial part. The front end surface 126, or the

  outer surface, is threaded at the periphery.

  In assembly, the separate part 122 is fitted into the central hole 127 formed in the separate part 121 while turning the separate part 122 in such a way that the threaded part 123 couples to the threaded part 126 The separated parts 121 and 122 are toured respectively

  in directions indicated by R 1 and R 2.

  Of course, one of the separate parts can be kept at rest. In this way, the wheel 120 having windows 128 is completed as shown in Figure 2 B. Figures 6 A and 6 B illustrate the manner in which the wheel 12 shown in Figure 2 A is - assembled The internal threaded surface 131 of the separate part 12 A and the external threaded surface 132 of the separate part 12 B are screwed together to couple the separate parts 12 A and 12 B together. external threaded part 12 C is screwed into the internal threaded surface 133 of the separated part 12 B The external threaded surface of the separated part 12 D is screwed into the internal threaded surface of the separated part 12 C. The shapes of the parts which adjust are described in the following The parts which adjust are firmly coupled together

  by screwing the convex part into the concave part.

  Figure 7 A is a cutaway perspective view of a pair of fitting parts Figure 7B is a sectional view along the plane BB of Figure 7A In these figures, the separate molded parts 14 A and 14 B have a thread

  outside and an internal thread on their

  respective adjustment faces Thus, the separate parts 14 A and 14 B couple one after the other, and can be screwed into each other by turning them in opposite directions indicated

R 1 and R 2 respectively.

  As shown in Figures SA, 8 B and 8 C, the parts that adjust can be threaded at several levels This structure allows the separate parts 14 A and 14 B to be adjusted

  together more solidly and more rigidly.

  As shown in Figures 9 A and 9 B, screw threads each taking the shape of a sawtooth can be formed to prevent the adjusting parts from loosening and to increase strength The wheel, 140, It includes a separate part 141 on the side of the rim and a separate part 142 on the side of the center of the hub The thread 144 on the outer surface of the separate part 142 is screwed into the thread 143 on the inner surface of the separate part 141 Both

  threads 143 and 144 extend peri-

  spherical The saw teeth 145 and 146 are formed regularly at the periphery Consequently, the separate part 141 does not rotate in the opposite direction, namely the direction to loosen it. As shown in Figure 10, the coupling of parts that adjust to multi-level using a bolt 16, rivet or the like is effective

to prevent loosening.

  As shown in Figure l IA, if the tension forces F and F act in directions

1 2

  opposite, the parts that adjust disengage

  will manage one from the other, thus disengaging one from the other the separate parts 14 A and 14 B. To avoid this disengagement, an improvement in the form of the threads of the parts which adjust is effective con-me shown in Figures

11 B-11 F.

We must understand that the forms

  to avoid loosening and constant disengagement

  simply kill examples of the invention and that any other form can be adapted within the scope of the invention to the extent

or the goal is reached.

  In the new resin wheel, an adhesive is sandwiched between the concave and convex fitting surfaces of the separate molded parts 14 A and 14 B shown in Figures 7 A-11 F, or an adhesive is placed in between between the contact surfaces of the separate molded parts 14 A and 14 B between the adjacent levels of the parts which adjust to multi-levels, to link together the separate parts 14 A and 14 B. Alternatively, the parts are linked together by thermal melting These configurations are quite effective for improving the resistance of the parts which adjust and also for

  avoid loosening and disengagement.

  The separate parts of the new resin wheel can be molded from any synthetic resin including different

  thermosetting and thermoplastic resins.

  More specifically, thermo resins

  curable materials include phenolic resin, epoxy resin, unsaturated polyester resin, vinyl ester resin, polyurethane resin, diallyl phthalate resin, alkyd resin, urea resin, melamine resin and their modifications Of these substances, resin unsaturated polyester, vinyl ester resin, phenolic resin and epoxy resin are preferred Especially, vinyl ester resin and polyester resin

  unsaturated are preferable These thermoset resins

  can be used alone or in combination

combination.

  Thermoplastic resins include various polyamide resins, such as Nylon 6, N ylon 6 6, Nylon 4 6, Nylon 6 10, Nylon 10, Tiylon II, and Nylon 12, polybutylene terephthalate (PBT), polyphenylene sulfide (PPS) , acetal resin (POM), polycarbonate (PC), polyethylene terephthalate SR 6433 JP / GL (Irregularity) (PET), pofypropylene (PP), polyether sulfone (PES), polysulfone (PSF), polyether ether ketone (PEEK) , polyphenylene oxide (PP 0), polyamideimide (PAI), polyimide (PI), polyester and different liquid crystal polymers From these materials, different polyamide resins, PBT, PPS, POM, PC, PES, PI, PAI, PEEK , polyester and different polymers of liquid crystals are preferable These thermoplastic resins can be used alone

or in combination.

  It is possible to add to the resins described above a necessary quantity of various fillers, aging-resistant agents, crosslinking agents, oils, plasticizers, oligomers and elastomers to improve the capacity. exposure, heat resistance, wear resistance, fluidity, coeficient of thermal expansion, resistance to flan-me, chemical resistance and others

characteristics.

  In the present invention, the reinforcing fibers added to the synthetic resin described above can consist of glass, carbon, graphite, aramid, polyethylene, ceramics such as Si C, and A 1203, metals such as boron, and stainless steel If the diameter of the reinforcing fibers is too small, then the resin

  synthetic is not sufficiently reinforced.

  Conversely, if the fiber diameter is too large, then it is difficult to perform injection molding and the moldability is low. Consequently, the diameter of the reinforcing fibers is 0.1 to 100 µm, preferably

0.5 to 50 pm.

  If the amount of reinforcing fibers

  cement added is too small, so the reinforcement

  cement does not produce a sufficient effect Inver-

  If the amount is too large, then the amount of resin forming the matrix is

  insufficient and the moldability is poor.

  Consequently, the ratio of the amount of reinforcing fibers added to the amount of molding material is preferably 5 to 5% by volume, more preferably 10 to 60% by volume.

  The special molding material used

  preferably in the present invention

  includes continuous fibers and thermo-resin

  plastic These materials are molded according to an extrusion by drawing into rods having a diameter of 2.5 to 3 nrm These rods are cut into blocks of 10 nmm long In this case, the length of the reinforcing fibers present can be adjusted as desired by controlling the cutting length as described above Since the blocks are formed by stretch extrusion the intervals between the fibers are sufficiently impregnated with resin although the fibers are long This type of resin reinforced with long fibers is much higher in terms of mechanical properties, with normal resin reinforced with short fibers as described above, but the aptitudes for molding or shaping are greatly deteriorated; the molding and shaping properties of the resin reinforced with long fibers are fairly comparable to

  those of resin reinforced with short fibers.

  The addition of a normal resin reinforced with short fibers is quite effective in improving the workability of the resin reinforced with long fibers In this case, the added amount of resin reinforced with short fibers s raises to less than 70% by weight of the total amount, preferably

less than 60%.

  In the present invention, any of the moldings can be used.

  compression, injection and injection-

  compression to mold the separate parts from the materials described above A casting line which would normally be produced by injection molding can be avoided by dividing the wheel into two or more pieces Taking this fact into account, it can be said that the the present invention especially gives great advantages when the wheel is molded according to a molding by

  injection or injection-compression molding.

  The separate molded parts of the resin wheel can be formed using any of the three methods described above or by

  using a combination of several methods.

When injection molding-

  compression is used, the molding dies are opened slightly, or the molding dies are closed with a low clamping force Then the material is injected into the

  mold After that, the clamping force is increased

  to mold the wheel under compression.

  When injection compression molding is used, a molten resin is injected between the upper and lower molding dies

  using an injection cylinder or an extru-

  deuse, the dies being mounted between presses.

  The molds are closed before or after the

supply of resin.

  In recent years, energy saving has been required at the request of society seeking environmental protection. Thus, it has been demanded that automobile components be reduced in weight. Especially, the lighter unsprung components produce marked effects Elements not suspended on a spring are also required to be reduced

  in weight to improve handling.

  For these reasons, it is desired that a wheel be equipped with a combination of a reinforcing structure to further improve the

  strength and weight reduction structure.

  These structures can be introduced into the entire wheel, or they can be installed only in the rim, disc or

in another desired position.

  An example of a reinforcement structure is shown in Figure 12, where a type of layer

  reinforcement is formed as an inter-

  middle 18 of the wheel body 17 or as a surface layer 19 In this reinforcement layer, the reinforcement fibers are contained in increased proportion Otherwise, the intermediate layer 18 or the surface layer 19 is

  composed of reinforcing elements or the like.

  In Figure 12, the border line between the parts

separate molded is omitted.

  In this case, examples of materials for the reinforcing layer include glass, carbon, graphite, aramid, ceramics, such as Si C and A 1203, and metals, such as boron and stainless steel These materials can take different forms Optimal forms include textile glass roving having long fibers arranged in lines in one direction in mesh, braid, twist, resin band, or sheet-of-resin in which the fibers arranged are maintained, and fabric woven in three

dimensions.

  Where a reinforcement layer is inserted in a wheel, the molding of the insert is used with profit. That is to say that a filling agent of a given shape is molded beforehand The molded filling agent is placed in a given position inside the mold, and then the wheel is molded according to

injection molding.

  Normally, a wheel is fixed via a hub bolt to the disc adjacent to the brake drum or brake disc and thus the surroundings of the hole for the hub bolt are subjected to the heat created by the brake If the wheel is used during a long-term, the resin softens or a creep

  product, leading to a relaxation of tensions.

  This results in the hub nut loosening The structures to solve this problem are shown in Figures 13 A, 13 B and 13 C Figure 13 A is a sectional view of the surroundings of a hub Figure 13 B is a sectional view of part B of Figure 13 A Figure 13C is a sectional view along the plane CC of Figure 13 B. A ring 20 of high rigidity, high mechanical strength and heat resistance , is fitted in the hub bolt hole 3 of a resin wheel 10 Preferably, the force with which a hub nut 23 is tightened on a hub bolt 21 is transmitted to a brake drum 24 via the ring 20 In 25 is indicated the tire The optimum materials of the ring include metals, heat resistant plastics, heat resistant plastics reinforced by fibers, carbon composites reinforced by

carbon fibers, and ceramics.

  Thermal insulation can be formed by insert molding on those surfaces of the disc or rim that face the brake drum to provide insulation for heat from the brake drum As shown in Figure 14, this thermal insulation can be formed on a part 31 of the surface of the disc 2, on the total surface of the disc 2, that is to say the surfaces 31 and 32, a part of or all of the surface 33 of the rim 1, or all of the surface of the side of the brake drum, i.e. surfaces 31, 32 and 33 The thermal insulation may consist of heat resistant plastics, ceramics, inorganic materials, sheets reinforced with these materials, and slate comprising asbestos or similar Any material can be used as long as it presents

  thermal insulation and high resistance.

  The new resin wheel has the advantage that a device with another function can be embedded in the wheel and molded in solidarity with the wheel Con-me example, if a device for warning of an anomaly such as puncture warning device is embedded in the wheel and molded integrally with the wheel, is offered a basic automotive component for safety in which a wheel is integral

  of a tire An integrated safety mechanism

  Reinforcement ribs extending vertically from the rim of a wheel can be easily molded integrally from the

wheel.

  The new resin wheels are used not only as automobile wheels such as passenger cars but also as vehicle wheels such as buses, trucks, railroad cars, metro cars, linear motor vehicles, airplanes, motorcycles, bicycles, golf carts, go-karts, and other recreational vehicles in the

leisure parks.

Claims (9)

  1 resin wheel (11) comprising two molded parts (l MA and ll B) independently or more, one of which is screwed into the other molded part or the other molded parts, so that the molded parts are adjusted and coupled together.   2 Resin wheel according to the claim   tion 1, in which the wheel comprises a rim (1) and a disc (2) and in which the wheel is divided into two parts molded at the level of the rim,   the two parts being coupled together.   3 resin wheel according to claim 1, wherein the wheel comprises a rim (1) and a disc (2) and wherein the wheel is divided into two or more molded parts at the   disc, all parts being coupled together.   4 resin wheel according to claim 1, wherein the wheel comprises a rim (1) and a disc (2), and wherein the wheel is divided into three or more molded parts at the rim and disc, all parties being coupled together.   A resin wheel according to claim 1, wherein the fitting surface of a separate molded part has an external thread, while the fitting surface of the other separate molded part has an internal thread in which the external thread is screwed.   6 resin wheel according to claim 5, wherein each of said threads has a plurality of levels.   7 Resin wheel according to claim, wherein a sawtooth screw thread is formed perpendicular to the direction in which the external and internal threads extend. 8 Resin wheel according to claim 1, wherein the sections which fit separate molded parts are locked together by bolt or rivet.   A resin wheel according to claim 1, wherein an adhesive is placed between the fitting surfaces of the separate molded parts. Resin wheel according to claim 1, wherein the fitting surfaces of the separate molded parts are bonded together by thermal fusion.   A resin wheel according to claim 1, wherein the wheel is made of blocks obtained by cutting rods which are molded from continuous fibers and a thermoplastic resin by stretch extrusion.   12 Resin wheel according to claim 1, in which the wheel is made of blocks obtained by cutting rods which are molded from continuous fibers and from a thermoplastic resin according to a stretch extrusion, and in which   the resin is reinforced with short fibers.   13 Resin wheel according to claim 1, wherein the separate molded parts are formed by compression molding, molding   by injection or injection-compression molding.