JPH0223361B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an automobile wheel and a method for manufacturing the same, and in particular to a method for manufacturing a fiber-reinforced composite wheel and a product thereof. As used herein, "composite wheel" and "fiber-reinforced composite wheel" refer to a wheel construction of fiber-reinforced plastic resin. The object of the invention is to provide an automobile wheel that has the same strength and durability as a regular steel wheel, but is lighter in weight and economical to manufacture. It is another object of the present invention that reinforcing fibers are placed in the wheel rim and disc portions and selectively oriented to increase durability and strength and/or to provide a structure that is more economical than conventional reinforced plastic wheel manufacturing techniques. An object of the present invention is to provide a method for manufacturing a fiber-reinforced composite wheel, which can be carried out in the following manner. Yet another object of the invention is to provide a wheel manufacturing device implementing the method described above. Yet another object of the invention is to provide a fiber reinforced composite wheel manufactured by the method described above. Still another object of the present invention is to prevent the formation of resin flow marks and bonding marks during the molding operation, particularly at discontinuous parts such as rim flanges, bolt holes and hand holes around the wheel disc. An object of the present invention is to provide a method for molding a fiber-reinforced composite wheel that minimizes. The invention and its additional objects, features and advantages will be apparent from the claims, the drawings and the following description. In this invention, the wheel rim and disc part are
A fiber reinforced resin molded wheel and method of manufacture is contemplated that is formed from separate mold charges of sheet molding compound. Separately formed charges are formed into a unitary composite rim and disk structure consisting of essentially homogeneous dentures reinforced with fibers. Preferably, the disk load consists of a stack of pre-cut sheet sections. The reinforcing fibers of the disk charge and final disk wheel section are randomly oriented when viewed in a plane perpendicular to the axis of the wheel. These planes correspond to the layers of reinforcing fibers in the sheet molding compound material. The rim charge is preferably one or more lengths of pre-cut sheet molding compound which are coiled to form at least one helix or hoop. Become. The sheet layer in the rim loading wheel will be referred to herein as a helical ply.
Preferably, the reinforcing fibers of the rim loading wheel body and the final rim wheel section include at least first fibers oriented substantially randomly around the rim periphery and selected fibers in one or more directions with respect to the wheel axis and periphery. A second directional fiber is included in the direction. In various embodiments described herein, the directional fibers are oriented coaxially parallel or circumferentially with respect to the wheel axis. In another embodiment, the directional fibers are arranged in a double helix forming an X-pattern across the wheel rim. By way of background to this invention, a line for preparing one type of sheet molding compound of fiber reinforced plastic utilized in the practice of this invention is shown in FIG. When the thermosetting resin paste 10 is pulled onto a continuous sheet 14 made of polyethylene film by a doctor blade 12, that is, a device for adjusting the amount of paste (called a doctor knife), on an endless belt conveyor 16. ,
Supplied in metered quantities. The paste 10 comprises an unsaturated polyester, vinyl ester or epoxy resin, thickeners such as oxides or hydroxides of Group II metals, catalysts such as organic peroxides or hardeners, inert fillers such as CaCO ₃ or clay, and mold release agents such as zinc stearate are included. In a first stage 18, a continuous fiber filament or strand 20 is transferred to a roller 2.
2 and chopped by a multi-knife roll arbor (shaft) 23 to form discontinuous fibers 24, which are transferred by gravity onto the paste layer 25, essentially in a substantially disordered manner on the surface of the resin layer. to fall. The fiber orientation disorder obtained in processing step 18 is shown schematically at 26 in the plan view. Preferably, the strands 20 are drawn from inside a fiber ball or roll (not shown) so that the chopped discontinuous fibers 24 are randomly twisted within the resin layer. Among the glass fibers used as reinforcing fibers in this way,
Especially E-glass (99% of the total production of long glass fibers)
(name of alkali-free glass fiber developed for electrical products) and S-glass (high strength,
(name of high modulus glass fiber) is preferred. In a second processing step 28, continuous fiber filaments 30 are placed on the resin layer 25, parallel to the running direction of the conveyor 18, evenly spaced and parallel to one direction on the disordered discontinuous fibers. The fiber pattern at stage 28 is shown at 32 in plan view. To prevent twisting of the continuous fibers 30 within the sheet molding compound, the fiber strands are drawn from the outside of the roll 34. A second layer 35 of paste 36 identical to paste 10 is metered onto a second polyethylene film 40 by doctor blade dam 38 and conveyed by rollers 42 onto running film layer 25 to form plastic resin sheet material layer 25, essentially in the middle between 35,
A sandwich body is formed in which continuous fiber strands 30 and discontinuous fibers 24 are arranged. In a third processing stage 44, a radially projecting blade 46 held in an arbor 48 penetrates the upper film layer 35 and cuts the continuous strands 30 in discontinuous and parallel strands as shown at 50 in plan view. to form a substantially unidirectional fiber pattern. blade 46
The individual strands 3 are arranged around the surface of the arbor 48.
0 at selected intervals to form discontinuous, parallel, substantially unidirectional fiber strands 52 having a desired selected length and staggered arrangement. The sandwiched sheet is then clamped by rollers 54 and rolled onto a roll 56 of forming stock comprised of continuous sandwiched sheet material. Resin raw materials are 5000~
Maturation to molding viscosity of 60000Pa-sec
It must be made viscous. In FIG. 1, the directional fibers are shown thicker than the disordered discontinuous fibers 24 at 30, 52, but this is for contrast only; in actual practice, the fibers are usually of the same type. have the same thickness. As another preferred processing method, the film layer 35
The step of cutting the strands 30 through can be performed after the roll 56 of continuous sandwich sheet material is formed. In this case, the arbor 48 is not provided in the processing apparatus shown in FIG. 1, but is located in another machine (not shown). After the molding raw material becomes viscous or matures, that is, the polyester resin and the Group 2 metal oxide or hydroxide undergo a hydroxyl-carboxyl ion reaction,
This reaction causes the paste layer 35 to have a viscosity of 5,000 to 5,000.
After sufficient time has elapsed to proceed to reach 60,000 Pa-sec, the forming stock is fed to the underside of the arbor to penetrate the film 40 and cut the strands 30. The penetration and cutting of the strands 30 in this high viscosity state of the molding material consisting of the sandwiched sheet material reduces the amount of resin squeezed or transferred through the film 40. As will be apparent, the processing steps schematically shown in Figure 1 do not result in multi-layer directional-disorder orientation (as shown at 50), but rather in sheet forming, e.g. with randomly oriented fibers or with only continuous fiber orientation. It can be applied when forming raw materials. For example, processing steps 28 and 44 may be deactivated so that the rolled sheet stock contains only disordered chop fibers 24 in the form shown at 26. Similarly, in processing steps 18 and 44, the final rolled raw material is
The actuation can be deactivated to include only continuous parallel strands 30 in the configuration shown at 32. In order to prevent the fiber strands from reorienting or twisting due to the possibly serrated roller surface, it is useful to cover the tightening roller 54 with an endless belt or the like. Disorganized fiber forms, as shown at 26, and disordered-oriented forms, as shown at 50, are particularly useful in wheel manufacturing. Although not preferred, the present invention may also utilize a configuration consisting of disordered fibers and continuous fibers, as shown at 32, for wheel production. For a discussion of the manufacture of sheet molding compounds of the type described below, see U.S. Pat.
Volume 86, No. 3, March 1978, P27-33; “Structure
SMC: Materials, Processing and Performance Review,'' Owens, Corning Fiberglass Corporation, Pub. 5-TM-8364, 1978, etc. Glass fiber reinforcements, including E-glass and S-glass, which are preferred herein, are discussed in "Evaluation of Glass Fiber Reinforcements", Plastic Compounding, July/August 1978, P14-25. In the thickening or ripening process, Disk et al., "Magnesium Oxide and Hydroxide for SMC," Modern Plastics, November 1974, P94-98; and Raohn et al., "Unsaturated Polyester "Rapid Aging of Resin Prepregs", German Plastics, translated from Kunststuffe, Volume 65, October,
1975, pp. 678-680. A method of forming a fiber-reinforced composite wheel according to the present invention is illustrated in FIGS. 2-4. Referring first to FIG. 2, a continuous strip of fiber-reinforced plastic resin molding stock is first coiled to form a multi-spiral layer or ply rim-forming charge wheel 60. The sheet-form forming raw material is processed by the roller 56.
(FIG. 1) and then coiled. In this case, polyethylene films 14 and 40 are removed. In addition, when the sheet-like raw material is manufactured by the method described in relation to FIG.
Cut from the roll 206 shown. The rim part therefore consists of distinct circumferentially arranged layers in the radial direction of the wheel to be molded, i.e. radially stacked circumferential layers, each layer extending in a given direction with respect to the axis of the wheel. It will contain oriented fibers and randomly arranged fibers. The particular rim charge embodiment shown at 60 in FIG. 2 consists of three spiral plies coiled from a continuous length of raw material and having overlapping ends 61. In practice, sheet molding compound is not always commercially available in sufficient length to form hoop 60 from a continuous length of strip stock. In such cases, it may be necessary to "splice" the ends of the short sheet lengths. It is anticipated that sheet strips of desired lengths will be available for high volume manufacturing of wheels. Some of the embodiments discussed herein have different types, i.e. different fiber orientations,
Includes sheet molding compounds that require multiple lengths of strip stock. In either case, the number of spiral plies required will depend on the number of different types of sheet molding compound required and the wall thickness of each sheet. Wheel 60 in FIG. 2 is for illustrative purposes only. Wheel 60 is formed by winding a coil around a rotatable mandrel (not shown) to a diameter approximately equal to the final desired center diameter of the wheel rim. If the wheel rim is of the type with a bead retaining flange on one or both ends of the rim, before placing the wheel in the wheel mold,
It is useful to stretch the axial wheel ends outwards. Therefore, the wheel body 60 is formed at the wheel end portion 68 to form a first preform 69.
It is preferably mounted on a rotatable die 62 with an outer surface 64 that cooperates with a rotatable roll follower 66 to form a slight outward flare. The expanded rim-loading wheel preform 69 is then placed between the two radially outwardly opened rim-shaped halves 72, 74, with the expanded lower end 68 resting on the upper surface of the lower disk-shaped half 84. placed so that it is The mold halves 72, 74 are connected to fluid cylinders 77, 79 (FIG. 3) by push rods 73, 75 and are slidable inwardly on guideways 76, 78. Cylinders 77, 79 are connected to and operated by appropriate hydraulic control devices 85. Radial inner surface or molding surface 8 of mold halves 72, 74
1 and 83 are each preferably contoured to form a suitable tire bead seat, bead retention flange, and rim well on the outer surface of the rim. Stretched loading wheel preform 69
However, the disk type body 84 is formed between the rim type halves 72 and 74.
Once placed on top, the rim halves are closed and the preform 69 is radially compressed and captured. In the continuous manufacturing process, the mold halves 72, 7
4 is maintained at a high temperature of 132°C (approximately 270°C) to 160°C (approximately 320°C). In FIG. 3, a fiber-reinforced (plastic) suitably cut from a roll of raw material similar to roll stock 56 after peeling off films 14, 40.
A plurality of flat sheet sections of sheet molding compound are stacked one on top of the other to form disk loading section 80. Disc loading piece 8
The preferred raw material roll utilized to form the 0 is as described in connection with FIG. 1, except that the continuous fibers 30 are omitted and the step of cutting the continuous fibers 30 through by the arbor 48 is omitted. is formed similarly. The disc loading pieces are placed in the molds coaxially within the rim-shaped loading 69 on the molding surface 82 of the lower disc mold 84. The disk loading piece 80 therefore consists of distinct layers, axially stacked, in the axial direction of the wheel being molded, each layer having reinforcements such as discontinuous fibers 24. The fibers will be randomly oriented and arranged with respect to the axis of the wheel.
As shown in FIG. 3, a disk loading member 80 extends into the mold and upwardly from the mold and cooperates with a cavity 100 in the upper disk mold body 94 to form a disk hand hole pocket as described below. It is supported by a horn 90 for use. Preferably, each disk loading section 80 is substantially square, with the corners of the sections staggered circumferentially in a rosette pattern so that the disk-shaped surface 82 is at its maximum. are stacked so that they are covered. This special configuration allows material flow and
The resulting bond line traces on the final disk are minimized. Mold pieces 84, 94, and 120 (in addition to mold pieces 72, 74) are heated to the aforementioned 132° C. (approximately 270° C.) during and during the molding process or operating cycle.
It is continuously maintained at a high temperature in the range of 〓) to 160℃ (approximately 320℃). If the final wheel is of the type that includes a hub extending axially from the main portion of the disk, a number of small square hub-loading seat pieces 86 are inserted into the disk loading section above a cavity 88 formed in the mold surface. It is located between the piece 80 and the mold surface 82. The cavity 88 is located on the opposing surface 9 of the upper disk type body 94.
In cooperation with the horn 98 attached to 9, a hub pocket is formed in the wheel disc. Piece 86
is the cavity 8 when the disc type body is closed.
Helps eliminate air that would otherwise be trapped within the 8. Outward radial surface 1 of disk-shaped body 84, 94
01 and 103 respectively cooperate with surfaces 81 and 83 to define a rim recess, flange and bead seat rim portion of generally uniform wall thickness in the mold cavity shape. The number of plies of disk loading pieces 80, 86 and rim loading 69 of FIG. 3 is determined by the desired wheel wall thickness and sheet stock density. As previously discussed, the disk loading pieces 80 are placed in a pattern that substantially covers the mold surface, thus providing approximately the final disk shape and reducing material flow during subsequent compression molding. It is desirable to place the Given any particular density of sheet molding compound and desired wheel dimensions, one skilled in the art can readily determine the number of plies, etc. to fill the mold volume with a minimum of overflow conditions. Ru. It is also contemplated that square charges may be utilized to form other shaped disks other than the rosette-like stacks preferred herein, such as four-spoke disks. 3 and 4, the next step in the compression molding operation is to move the lower disc mold 84 upwardly from its resting position on its lower stop 92 and simultaneously move the upper disc mold 94 downwardly into the fluid control system. 85, the disk mold body corresponds axially and is in the initial molding position within the closed rim molds 72, 74, and very close to the fully closed and final molding position shown in FIG. is moved until the position is reached. Preferably, the movement of mold bodies 84, 94 is controlled such that the mold bodies move relative to each other and reach their final positions (FIG. 4) substantially simultaneously.
The movement of the upper mold body must be well controlled, since the upper mold body 94 must initially be positioned at a distance from the mold bodies 72, 74 and 84 so that the mold charge can be positioned. It won't happen. The mold body 84 is guided by an enclosing sleeve 120, which is provided with an axial stop shoulder 122 that cooperates with a lip 126 on the mold body 84 to limit upward movement of the disk mold body. The mold body 84 is also connected by rod 124 to a suitable hydraulic cylinder (not shown). A sleeve skirt 96 axially protrudes from the radially outer end of the upper mold body 94 .
When lowered, it catches the rim-shaped bodies 72, 74 and clamps the rim-shaped bodies, and at the same time, the disk-shaped body 9
4 to a predetermined position. The horn 98 on the upper mold surface 99 initially loads the hub charge 86 into the opposing cavity 88 of the lower mold body 84.
form. At the same time, the horn 90 first forms a disk loading piece 80 in a corresponding recess 100 in the upper mold surface, first forming a circular row of pockets 102.
(FIGS. 4-7), the pockets 102 are offset from the wheel disc 104 and are joined together by a narrow circumferential continuous bridge 106 around each pocket. The closed mold is then subjected to high pressures on the order of 150 psi (10.3 megapascals) for on the order of 5 minutes at elevated temperatures of 132°C to 160°C to form an essentially compressed fiber-reinforced material reinforced by compression molded dispersed fibers. A homogeneous resin integral rim and disk structure is formed. The mold body is then opened in the reverse order to that described above and the mold wheel 116 (FIGS. 5-7)
is taken out for finishing. In this case, a particular advantage of the forming method hitherto described is the use of a movable lower disc mold in combination with the step of stretching out the ends of the rim charge to form the open flange 68 as described above. This is thought to be due to the fact that it was established. 2-4, the slightly retracted position of the lower disk mold body 84 when the flanged rim charge 69 is placed in the mold results in the final outer rim flange The lower flange portion of the rim charge, designated 122 (FIG. 6), may be positioned proximate the flanging surface of the rim molds when the rim molds 72, 74 are closed. This means that no molding material is "pressed" into the flange area when the disc mold is closed. This results in
The reinforcing fibers are more evenly distributed on the flange than if the mold body 84 were fixed. This is especially
This is important when fibers transverse to the wheel rim are utilized, as discussed in Figures 13-17. In wheel manufacturing molds, rim molds with more than two mold bodies can also be utilized within the scope of this invention. The molded wheel 116 includes integral bead retaining flanges 122, 123 and bead seats 126, 1.
It includes a rim portion 120 with a central recess 124 (FIG. 6) connected to a flange 122 by 27. As shown in FIG. 6, the recess 124 is offset or asymmetrical with respect to the rim centerline, i.e., the recess 124 is closer to the outer flange 122 than the inner flange 123 ("outer" and "inner" are (mentioned relative to the preferred orientation of the final wheel mounted on the wheel). A disc portion of wheel 116, indicated generally at 130, is connected to rim portion 120 at the lower outer end of recess 124. The outer surface of the disk 130, as shown in FIGS. 5 and 6, includes five circumferentially spaced radial ribs 1 in symmetrical rows alternating with the aforementioned pockets 102.
It includes 32. Each rib 132 has a recess 124
The hub shell 134 extends widely from a position adjacent to the hub shell 134 and flares out into an outwardly cup-shaped hub shell 134 at the center. Rib 13
2 not only reinforces the wheel, but also gives it a decorative spoke shape. The outer surface of shell 134 includes an axially extending channel 138 that is radially aligned with the center of each pocket 102. The ribs 132 are hollow, ie, a pocket 136 extends into each rib 132 on the inner surface of the wheel disc, as shown in FIG. Each rib pocket 136 has a pair of reinforcing ribs 140 (seventh
) straddles the rib 140 and the recess 124.
It is stretched out to the base of. Similarly, each hand hole 110 is surrounded by a continuous reinforcing trellis or bead 141, as shown in FIG.
The radially outer portion of each trough-shaped portion 141 is connected to the pocket 14.
4 (FIGS. 6 and 7) from the rim recess 124. Between the rib 132 and the opening 110, the disk portion 130 narrowly tapers from a thickened region 146 (FIG. 6) adjacent the shell 134. During finishing operations, the bead retaining flange 12
The burr is removed from the end of 2,123. The bottom and side edges of each pocket 102 are aligned with the dashed line 1 in FIG.
08, a circular row of openings or hand holes 110 (8-1
0), which cooperate with the ribs 132 to give the wheel as a whole a spoked configuration. Hub central hole 114 is drilled at the base of shell 134 .
A circular row of mounting holes 112 are drilled into the thickened portion 146 of the wheel disc 130, coaxially with the pilot surface 113 of the wheel (FIGS. 6 and 9).
or formed by other means, the bolt holes 112 are spaced outwardly in radial alignment with each channel 138 in the hub shell outer surface. An opening 150 is drilled into the rim 120 for the expansion valve. Although finishing operations are required on the forming wheel, such as removing the pockets 102 and drilling the bolt holes 112, forming the solid disc described above reduces the tendency for bond lines to form in the molded part, and The strength and durability of the finished wheel 114 is increased. The molded and finished wheels are 116 (Figs. 5-7) and 1, respectively.
17 (Figures 8-10). According to the invention described above, and the first
When manufacturing wheels using the sheet molding compound shown in the figure, glass fiber/resin weight ratios of approximately 45% to approximately 75% were tested, and fiber/resin weight ratios of 50/50 were tested. preferable. At fiber/resin ratios lower than 30%, there is too little fiber reinforcement for the manufacture of automobile wheels, and at ratios above 75% the "wetting limit" of the glass fibers is exceeded, thus reducing formability. However, the adhesion between resin and glass deteriorates. As mentioned above, the paste contains a small amount of catalyst, etc., and contains about 50% resin and about 50%
% filler. When manufacturing wheels in accordance with one embodiment of the present invention, a disordered pattern 25 (FIG. 1) and an oriented/disordered pattern 50 for disk loadings and rim loadings, respectively.
is particularly useful. Preferably, but not necessarily, the rim charge is coiled such that the oriented fibers are radially inward of the disordered fiber layer in each charge ply. The disordered fiber 24 is
Oriented fibers 52 having a length between 1.25 cm and 10 cm, with all fibers having the same length and preferably 5 cm.
The length is between 5cm and 30cm, preferably 20cm.
The useful range of fiber length as a fiber/weight ratio is determined by strength and formability. preferred 50%
By utilizing the glass fiber weight ratio of 5/
Oriented/disordered fiber weight ratios ranging from 45 to 45/5 are contemplated, with a range from 20/30 to 30/20 being preferred. In one wheel made in accordance with this invention, the disk charge consists of multiple plies of 50% by weight disordered fibers, the disordered fibers 24 having a length of about 2.5 cm and essentially perpendicular to the mold axis. facing a flat surface. The rim loading consists of a hoop of oriented/disordered sheet molding compound containing 50% fiber by weight, the rim loading hoop comprising:
Oriented fibers 52 in each ply include disordered fibers 24
The coil is arranged radially inward and wound in a coil so as to face in the circumferential direction. The disordered fibers 24 are therefore essentially arranged in a spiral direction rotating about the mold axis. The oriented fibers 52 have a length of 20 cm, the disordered fibers 24 have a length of 5 cm, and the oriented/disordered fiber weight ratio is 30/20. In the material specification for the disc and rim loading of the aforementioned example of a wheel according to the invention (see structure B3 of the table for test results):
"SMC" is the commercial designation for sheet molding compound. The particular compound utilized is manufactured by Owens Corning Fiberglass Company. D is 52 in Figure 1
represents an oriented fiber of the type shown, and R represents a disordered fiber 24. Therefore, SMC−R50 is 50
means a sheet molding compound containing % by weight of disordered fibers. (See Automotive Engineering above)

【table】

【table】

[Table] Paste composition and paste viscosity (same as for SMC-R50) For medium-duty vehicle wheels, a number of different wheel constructions have been manufactured and tested according to the following 1978 original equipment fatigue test specifications: Table: Dynamic Cornering Fatigue Disc Fatigue B ₁₀ -30000 cycles No failure below 20000 cycles Bending moment 2263N・m SEA J328a requires 18000 cycles Dynamic Radial Fatigue Rim Fatigue B ₁₀ -1000000 cycles No failure below 80000 cycles Radial load 12910N Test tire pressure 448K Pa SAE J328a requires 400000 cycles All wheels tested (except the D wheel construction) included SMC-R50 material in the disc loading pattern and were finished as described above. All wheels are identical to those shown at 117 in Figures 8-10. Various rim (belt) constructions are shown schematically in Figures 11-17 and the following table compares belt constructions and test results:

[Table] Figures 11 to 17 schematically show the installation of sheet molding compound in various belt structures according to the invention. In each of Figures 11-17, the stock is viewed from the side of the tire or radially outward of the rim charge. The bead-to-bead direction is vertical in FIG. 11, with horizontal dimensions broken away for ease of illustration. FIG. 11 shows Structure A in the table, where the belt is made of 50% by weight disordered glass roving (e.g., SMC-
Constructed from a three-spiral ply sheet molding compound containing R50). Although the test results for Structure A are good, this choice of belt material results in less wheel-to-wheel uniformity than desired. FIG. 12 shows the structure previously described in detail and shows test results for different glass compositions and lengths in the exemplary structures B ₁ , B ₂ , B ₃ and B ₄ of the table. In the various types of sheet molding compounds produced according to FIG.
Essentially separate layers are deposited in separate steps. FIG. 12 shows a preferred orientation in which the disordered fibers of each ply are located radially outward of the oriented fibers in that ply with respect to the rim charge axis. Three to six plies are required depending on the thickness and density of the material. The oriented fibers are oriented in the circumferential direction of the wheel rim. As is clear from the table, structure B ₃
has given good test results. FIG. 13 shows a belt structure consisting of sheets wound in a continuous spiral.
It contains circumferentially oriented fibers as described above. The belt structure also includes separate loading pieces with fibers disposed between each ply and axially aligned when the sheet is helically wound. Belt structure C is shown. This charge cuts individual pieces from a first continuous strip of sheet molding compound and then places the pieces side by side before being spirally wound onto a second strip. Manufactured by placing The oriented fibers in the continuous spiral ply are oriented in the longitudinal direction of the strip and thus essentially in the circumferential direction of the charge axis. However, the fibers in the loading piece are axially oriented. In other words, the reinforcing fibers in this belt structure form a lattice-like pattern oriented in the circumferential and axial directions of the rim and wheel. become. Wheels molded from rim charges manufactured and tested under load will
It was operated for 8.7 M (hundredth) cycles (Structure C in the table). In this regard, the table shows structures A and B ₂ ~
All of the wheels actually tested, illustrated as G, were previously described in connection with FIGS. (excluding wheels of structure D). Therefore,
Disk performance was believed to be consistent overall with Structures A and B ₃ and was not tested (with the exception of Structure D wheels). It is also contemplated that continuous oriented fibers may be used in the rim loading. However, discontinuously oriented fibers are preferred over circumferentially continuous rim-load fibers;
This is because the processing method described here provides good moldability, that is, the reinforcing fibers can be separated in the circumferential direction of the hoop blank 60 during the molding operation. Such separation is such that in the preferred method the rim charge is formed smaller than the final rim diameter and must be stretched circumferentially when hoop blank 60 is expanded within molds 62-66 and mold 74. must occur from
There is a concomitant increase in fiber separation. Another example of a modification is the rim loading hoop 60 (second
It is envisaged that the three-layer spiral winding for Figure) is replaced by three separate concentric hoops with circumferentially staggered overlapping joints. Rim loads are also featured in the July 1977 issue of Plastics World magazine, ``Best SMC and BMC-
It can be constructed from a single coil of thick-walled molding composition (TMC) of the type described in the article ``Miscellaneous''. Similarly, the rosette-type charge pattern 80 (FIG. 3) may be replaced with a single sheet section of US Steel's trademark TMC.
Such modifications can be applied in all directions, i.e. not only in the plane perpendicular to the wheel axis
There are potential advantages when utilizing TMC-R to yield fibers. Therefore, although SMC is preferred for forming the wheels of this invention in the embodiments described so far, TMC can be utilized and is widely utilized in the present invention. Figures 14 and 15 show complementary belt structures E and G (table), respectively. In structure E (FIG. 14), three inner layers of SMC-D/R, including the laterally oriented fibers of the wheel rim, are surrounded by plies of SMC-R50. Structure G (Figure 15)
In, SMC-R50 is the inner ply. In each belt construction E and G, three plies of D30/R20 compound weighing 2.0Kg and one ply of R50 compound weighing 1.3Kg result in a total weight of 3.3Kg. Fiber content is 50%, disordered (R)
is 31.8%, and oriented fiber (D) is 18.2%. The preferred range for both disordered and oriented fibers is 18-32
In weight%, the total amount is about 50% by weight. The test results are shown in the table. FIG. 16 shows a belt construction D consisting of one ply of SMC-R50 and two plies of sheet molding compound sold by PPG Industries, Inc. of Pittsburgh, PA under the trademark XMC. The sheet molding compound is prepared by depositing a plurality of continuous fibers 200 from individual creels (not shown) into a resin bath 202 according to the method schematically shown in FIG.
and a rotating mandrel 20 through a large number of small holes 204.
6. Manufactured by drawing upwards. Small hole 204
is attached to a carriage 208 that oscillates in a direction parallel to the axis of the mandrel 206, and the fibers 200 deposit multiple helical layers in both directions to form essentially a double helix pattern. A cutter/gun 210 is attached to the carriage 208 and picks up one or more fiber threads 21.
I have come to accept 2. These fibers are chopped (cut) to a predetermined length and passed through a mandrel 20.
6 is wound or laid down 214. Movement of the carriage 208 and chopper/gun 210 about the mandrel axis causes the chop fibers to be randomly or randomly deposited in a direction essentially or substantially parallel to the mandrel axis. These fibers will be referred to as "oriented-disordered" fibers. "Oriented-disordered" fibers are designated as DR in the table. The rocking speed of the carriage 208 relative to the angular velocity of the mandrel 206 is varied to control the helical angle of the fibers 200.
A comprehensive discussion of the method previously described in connection with FIG. 18 can be found in U.S. Pat. No. 4,167,429. Once the winding 214 is complete, the winding is axially cut and removed from the mandrel 206. To produce a wheel rim charge according to the present invention, the sheet is further cut in the direction of the mandrel axis, as shown at 216, to form a predetermined width corresponding to the rim width. The result is a plurality of strips of predetermined length, preferably 20.3 cm (8 in.) wide, one of which is
Partially shown in the figure. Each strip includes oriented fibers 222 in an essentially X-shaped pattern at acute angles across the strip, with oriented-disordered fibers 222
20 is oriented essentially in the longitudinal direction of the strip. The following are utilized in manufacturing wheels according to this invention and are discussed below:
The material details of XMC sheet molding compound are:

Table: The composition of SMC-R65 is the same as above except that it contains 65% 2.5 cm (1 in.) disordered fibers. Having a total glass content of 80% or more, the sheet molding compound becomes viscous and
Handling becomes difficult. For glass content below 55%, the resulting wheel rim is weak. If the helix angle is less than 79 degrees, the fiber ends of the rim flange will become too wide and the desired strength will not be achieved. Above 82°, the circumferential strength of the wheel rim decreases.
80.16[deg.] is the value that does not require modification in conventional winding machines and is utilized in the aforementioned angular range, and is preferred for this purpose in practice. 79゜～
The criticality of the helical angle within the range of 82° is unknown. Number of layers of oriented fibers, i.e. mandrel 20
6 must be sufficient to "fill" all the diamond-shaped openings between the oriented strands. Figure 16 shows the inner layer of SMC-R65 and the X-pattern/orientation-disordered sheet material (X/DR in the table)
A belt structure D consisting of two outer layers is shown. The total weight of each belt is 3.2Kg, consisting of 2.48Kg of XMC compound (total weight of two plies) and 0.72Kg of R65 compound. Total glass content is 65% by weight
on the order of 14.7% disorder (R), 10% orientation-clear order (DR) and 40.3% orientation or
It is made up of fibers. As is clear from the table, belt structure D provides very good results, especially considering that steel wheels are typically expected to operate for 800,000 cycles without fatigue failure of the rim. It is believed that the improved test results of Structure D are due, at least in part, to the oriented fibers in the lateral direction of the wheel rim, i.e. in the axial direction of the wheel. The improved forming method described above allows these transversely oriented fibers to extend into the rim flange, thus strengthening the flange bead seat radius, where fatigue failure is common in steel wheels. In fact, the most common form of final failure of wheels of construction D consists of a small crack in the front rim recess radius. As a result of this form of destruction, air slowly leaks out, so it can be said that this form of destruction is preferable when used on an actual expressway. Figure 17 shows a belt structure F consisting of X/DR plies sandwiched between SMC-R65 plies.
shows. For wheels with belt structure F manufactured and tested, the total belt weight is 3.2Kg
It consists of 1.92Kg of R65 compound (total weight of two plies) and 1.28Kg of XMC compound. As in Structure D, the total glass content was 65% by weight. In structure F, this total is 39% disorder (R), 20.8% oriented and 5.2
% orientation-disordered (DR) fibers. Preferred ranges herein for belts of structures D and F are about 15-39% disorder, about 4-11% by weight.
orientation-disorder, and approximately 19-40% by weight oriented fibers. A total glass content of about 60-65% is preferred, with 65% being particularly preferred. As is clear from structure F in the table, the results for this belt shape are not better than for structure D (FIG. 16). This is the outermost X/
This is believed to be due to the loss of lateral strength as a result of replacing the DR ply with the fully disordered (R) ply shown in FIG. Structure D of FIG. 16 is currently preferred. It is contemplated that another X/DR ply will replace one continuous length strip stock (lengths not currently commercially available) in manufacturing.
It is expected that wheel rims manufactured in this manner will be stronger than those previously tested by eliminating potential weaknesses where another ply was joined end-to-end. A disk structure consisting of stacked SMC-R50 is currently preferred. (Test results are in Table A and B ₃ ). 20-21 show another embodiment of a wheel molded according to the present invention, and 22-23
The figure shows the finished wheel. The wheels of Figures 20-23 are specifically designed for front wheel drive vehicles and feature substantially increased disc offset compared to the wheels of Figures 5-10. Elements of FIGS. 20-23 that are similar to elements described in detail in FIGS. 5-10 are designated with corresponding reference numerals followed by the suffix "a." Pocket coupling bridge portion 10 in FIG. 21
6a is substantially thinner than that at 106 in FIG. 6, which allows the pocket 102 to be broken from the wheel disc without the need for additional finishing operations. In another important feature of the invention, a quality control method for inspecting oriented fiber patterns within a molded wheel is contemplated. This configuration is achieved by winding oriented fibers of radiopaque material such as barium or lead glass onto a green sheet stock and forming it into a wheel. Thus, in the embodiment of FIGS. 16 and 17, the quality control aspect of the invention may be implemented by utilizing radiopaque fibers as one or more of the fibers 200 of FIG. 18. Similar modifications can easily be made to the SMC method of FIG. Then, molding and/or
Or the finished wheel is taken as a sample,
The laid state of the oriented fibers is examined by X-ray inspection. In the claims section, "oriented fibers" refers to fibers that have a controlled orientation within the green sheet forming stock and therefore an essentially controllable orientation within the forming wheel. Fibers 30, 52 (Figure 1) and 222 (Figure 18)
is an example of oriented fibers discussed in detail previously.
"Disordered fibers" refer to fibers that are oriented substantially randomly in at least one plane, as illustrated by discontinuous fibers 24 in FIG. "Oriented-disordered fibers" refers to disordered fibers that are controlled during the sheet molding compound manufacturing process to be oriented in a substantially predetermined direction, as shown at 220 in FIG. All orientation terms, unless otherwise specified, are with respect to the final wheel axis.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of forming one type of raw fiber reinforced plastic resin sheet molding compound utilized in practicing various embodiments of the present invention; FIGS. Figure 5 is a fragmentary elevational view of one wheel embodiment formed by the process of Figures 2-4; Figures 6 and 7 are respectively A fragmentary side cross-sectional and rear view of the wheel of FIG. 5 taken along lines 6-6 of FIG. 5 and 7-7 of FIG. 6; FIG. Elevated views, Figures 9 and 10 are 9-9 in Figure 8, respectively.
Fragmentary side cross-sectional and rear views of the wheel of FIG. 8 taken along lines 10--10 of FIG.
FIG. 17 is a schematic diagram of various configurations of rim charges for molding fiber-reinforced composite wheels according to the present invention, and FIG. 18 is a schematic diagram of sheet moldings utilized in carrying out various embodiments of the present invention. a schematic diagram similar to FIG. 1 showing an alternative method for providing the compound; FIG. 19 a fragmentary cross-section similar to a portion of FIG. 7 showing a modification of the wheel of FIGS. 5-10; Figures 20-23 are schematic illustrations of further embodiments of a wheel according to the invention, corresponding substantially to Figures 5, 6, 8 and 9, respectively. 24...Disordered fibers, 30, 52...Oriented fibers, 120...Rim part, 130...Disc part.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a fiber-reinforced composite wheel comprising an integral rim portion and a disc portion, the method comprising: coil-winding a first sheet portion of fiber-reinforced plastic resin to load a rim comprising at least one coil ply; forming a hoop, placing the rim-loading hoop in a mold, and placing another disk charge comprising at least one second sheet section of fiber-reinforced plastic resin in the mold within the rim-loading hoop; a method comprising the steps of: compression molding the rim loading hoop and disk loading to form a unitary fiber reinforced composite wheel; and removing the wheel from the mold. 2. A method according to claim 1, characterized in that before placing the rim loading hoop in the mold, the axial ends of the hoop are stretched open. 3. The mold includes a first mold body that can reciprocate in the radial direction and a second mold body that can reciprocate in the axial direction, and the step of placing the rim loading hoop in the mold includes the step of placing the rim loading hoop in the mold. is placed in the mold, and the first
capturing the rim loading hoop in the mold by closing the mold so that the axial end of the rim loading hoop extends into the cavity portion for forming the bead retaining flange; closing the mold body to trap the material forming the bead retaining flange within the cavity portion rather than forcing it to flow under pressure into the cavity portion by closing the second mold body. The method according to claim 1 or 2, wherein: 4. The method of claim 3, wherein the rim loading hoop is formed of a sheet molding compound containing oriented fibers extending in the axial direction of the hoop. 5. The second molded body is comprised of a plurality of parts, and the second molded body is closed by moving each of these parts so as to reach a closed position at the same time. The method described in Section 3. 6. A circular row of openings are provided around the disc portion so that the wheel as a whole has the appearance of having spokes, and at the location of each opening, a pocket is integral with the disc portion but offset from it. 5. A method of manufacturing a wheel that is molded in position, the method comprising the step of removing the pocket from the molded wheel to form the opening. The method according to any one of the above. 7. The disc part is in a non-porous state when the wheel is molded, and the claim includes the step of opening a circular row of mounting holes in the disc part for attaching the wheel to an automobile. The method described in item 6 of the scope of 8. Consists of a rim-shaped body that can reciprocate in the radial direction about the axis of the mold, and two disc-shaped bodies that form a mold cavity, and both of the two disc-shaped bodies are in a closed position that forms the cavity and in a closed position that forms the cavity. 1. A compression molding mold for molding a resin wheel for an automobile, characterized in that the mold is configured to simultaneously reciprocate in the axial direction between open positions spaced apart from the center. 9 A method for compression molding a fiber-reinforced composite rim for an automobile wheel, which comprises a first mold body that can reciprocate in the radial direction and a second mold body that can reciprocate in the axial direction, and the mold bodies are all common. A mold adapted to work to form a cavity for compression molding a wheel rim including a bead retaining flange is provided, a rim molding charge consisting of a hoop of reinforced resin sheet molding compound is formed, and all of the foregoing placing the rim loading hoop in the mold with the mold body open, closing the mold body under heat and pressure, opening the mold body and removing the rim. how to. 10. The method of claim 9, wherein the axial ends of the rim-loading hoop are stretched open before placing the rim-loading hoop into the mold. 11 The step of placing the rim loading hoop in the mold includes placing the rim loading hoop in the mold and closing the first mold body so that the axial end of the rim loading hoop is in the mold. capturing the rim loading hoop in the mold so as to extend into the cavity portion for forming the bead retaining flange, closing the second mold body and loading the material forming the bead retaining flange into the mold; 11. A method according to claim 9 or 10, characterized in that it comprises the step of trapping in the cavity part rather than forcing it into the cavity part by means of closure of the two molded bodies. . 12. The method of claim 11, wherein the rim loading hoop is formed of a sheet molding compound that includes oriented fibers extending in the axial direction of the hoop. 13. Claim 1, characterized in that said second mold body is composed of a plurality of parts, and said second mold body is closed by moving each of these parts so as to reach a closed position at the same time. The method described in Section 11. 14 Consisting of a disk portion and a rim portion, the reinforcing fibers in the disk portion are arranged in a plurality of distinct layers when viewed in the axial direction, and are oriented randomly with respect to the axis of the wheel in each of the layers. reinforcing fibers in the rim portion include first fibers oriented randomly with respect to the axis of the wheel and second fibers oriented in a preselected direction with respect to the axis of the wheel. A composite wheel made of fiber-reinforced resin, characterized in that the first fibers and the second fibers are arranged in radially distinct circumferential layers, respectively. 15. The second fibers include oriented fibers oriented parallel to the axis of the wheel.
A composite wheel according to claim 14. 16 the rim portion includes a bead retention flange;
16. The wheel of claim 15, wherein the oriented fibers extend across the rim and into the flange. 17. The wheel according to claim 14 or 15, wherein the second fibers further include oriented fibers oriented in a circumferential direction of the axis of the wheel. 18 Claim 15, wherein the oriented reinforcing fibers are intermittently discontinuous.
The wheel according to any one of Items 1 to 17. 19. Claim 1, characterized in that the reinforcing fibers have a structure selected from the group consisting of glass, aramid, graphite and carbon.
The wheel according to any one of Items 4 to 18. 20 It is made of fiber-reinforced plastic resin and includes a rim part and a non-porous disc part integral with the rim part, and a plurality of pockets that are homogeneous with the disc part are integrated with the disc part, and the pockets are connected from the disc part. Claims 14 to 19, characterized in that the wheel is removed to form an opening in the disk portion so that the disk portion and the wheel as a whole have an appearance as if they have spokes. The wheel according to any one of paragraphs.