Vehicle Wheel and Production Method Thereof
20230264513 · 2023-08-24
Inventors
- Tristan Timmel (Chemnitz, DE)
- Wolfgang Nendel (Oederan/OT Schönerstadt, DE)
- Mirko Spieler (Gelenau, DE)
- Sebastian Iwan (Chemnitz, DE)
- Torsten Vogel (Thum-Herold, DE)
Cpc classification
B29L2031/32
PERFORMING OPERATIONS; TRANSPORTING
B29C2045/14327
PERFORMING OPERATIONS; TRANSPORTING
B60B1/003
PERFORMING OPERATIONS; TRANSPORTING
B29C45/14311
PERFORMING OPERATIONS; TRANSPORTING
B60B2310/204
PERFORMING OPERATIONS; TRANSPORTING
Y02T10/86
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
B29K2077/00
PERFORMING OPERATIONS; TRANSPORTING
B60B1/0246
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
The invention relates to a stable one piece wheel, which is particularly suitable for cycles having an increased system weight such as electrically powered bicycles or cargo bikes, and a method producing said vehicle wheel. Said vehicle wheel comprises an annular portion (110), a plurality of spokes (120) and a hub portion (130) integrally formed by mould injection of fibre reinforced or carbo nano tubes containing thermoplastic, wherein each of the plurality of spokes (120) comprise a substantially Z-shaped cross section with a middle leg (122) and a pair of outer legs (121, 123), wherein the angle (γ) enclosed by each of the pair of outer legs and the middle leg is greater than a right angle and wherein the length of the middle leg (122) increases from the annular portion (110) toward the hub portion (130).
Claims
1. A vehicle wheel comprising: an annular portion, a plurality of spokes and a hub portion integrally formed by mould injection of fibre reinforced or carbon nano tubes containing thermoplastic, wherein each of the plurality of spokes comprise a substantially Z-shaped cross section with a middle leg and a pair of outer legs, wherein the angle enclosed by each of the pair of outer legs and the middle leg is greater than a right angle; and wherein the length of the middle leg increases from the annular portion toward the hub portion.
2. The vehicle wheel according to claim 1, wherein the middle leg is angled with regard to the rotational axis of the wheel.
3. The vehicle wheel according to claim 1, wherein each of the outer legs comprises at least one curved portion directed towards the middle leg.
4. The vehicle wheel according to claim 3, wherein the radius of the curved portion increases toward the annular portion.
5. The vehicle wheel according to claim 3, wherein the curved portions have a radius in a range between 3 to 20 mm and each Z-shaped cross section has a wall thickness in a range between 1.5 to 5 mm.
6. The vehicle wheel according to claim 1, wherein the length of the outer legs increases continuously towards the region for connection to the annular portion in order to widen the line, along which the Z-profile is connected to the annular portion.
7. The vehicle wheel according to claim 1, wherein the Z-shaped cross section of each spoke is configured to be torsionally elastic for the compensation of a load, which is directed substantially vertical to the outer periphery of the annular portion in a section between two adjacent spokes.
8. The vehicle wheel according to claim 3, wherein the outer legs of each Z-cross section is configured to allow deflection into the direction of a curvature.
9. The vehicle wheel according to claim 1, wherein the wheel comprises at least four spokes and the ends of the legs of each spoke are interconnected at the hub in order to form semicircular or at least partially elliptic windows defined between the annular portion and pairs of adjacent spokes.
10. The vehicle wheel according to claim 1, wherein said hub portion comprises a metal insert or a plastic insert connected with injection moulding or by utilizing residual heat of the injection molded hub portion configured to hold at least one of an axle, an electric motor, a hub dynamo, an internal gear hub or a wheel bearing, wherein the wheel suspension can be configured unilateral or bilateral.
11. The vehicle wheel according to claim 10, wherein the metal insert comprises apertures for an injection molded and form-fitting connection.
12. The vehicle wheel according to claim 11, wherein the hub portion is pseudo-pentagonal or pseudo-hexagonal shaped with rounded corners having at one side a radially inwardly extending rim for mounting an electric motor, wherein each of said corner comprises vertically extending pair of ribs for guiding the connecting elements and forming an air gap, when the electric motor is mounted.
13. The vehicle wheel in accordance with claim 1, wherein said fiber reinforced thermoplastic has a glass-fiber content of 20 to 65% by weight; and wherein said thermoplastic is selected from PA6, PA6.6 or a mixture thereof.
14. The wheel according to claim 13, wherein said glass-fiber-reinforced or carbon nano tubes containing thermoplastic has a tensile stress at break of 100 MPa to 300 MPa, and an E modulus of at least 6000 MPa.
15. The wheel according to claim 1, wherein the annular portion comprises a rim with an symmetric profile, which has two diverging legs directed radially outward, wherein each end portion has an integrally formed rim flange protruding inwardly towards the symmetry axis of the profile.
16. A method for producing a vehicle wheel, the method comprising the following steps: injection molding a fiber reinforced or carbon nano tubes containing thermoplastic to integrally form a one-piece body comprising an annular portion, a plurality of spokes and a hub portion, wherein the plurality of spokes form a substantially Z-shaped cross section with a middle leg and a pair of outer legs, wherein the angle enclosed by each of the pair of outer legs and the middle leg is greater than a right angle; and wherein the length of the middle leg increases from the annular portion toward the hub portion.
17. The method according to claim 16, further comprising connecting an insert of metal or plastic to the hub portion by injection molding through apertures of said inlet and backmolding at least a part of the insert in a force- and/or form-fitting manner.
18. The method according to claim 16, further comprising providing and extracting a plurality of radially arranged sliders with a collapsible core in the injection tool to form an annular portion comprising a rim with a symmetric profile, which has two diverging legs directed radially outward, wherein each end portion has an integrally formed rim flange protruding inwardly.
Description
BRIEF DESCRIPTION OF THE FIGURES
[0044] The accompanying figures illustrate exemplary embodiments of the disclosure and serve to explain, by way of example the principles of the disclosure and are not intended to be drawn to scale. The figures are included to provide illustration and a further understanding of the various aspects and embodiments, but are not intended to restrict the disclosure to the embodiment illustrated in the figures and are not necessarily to scale. Where technical features in the figures or detailed description are followed by references signs, the reference signs have been included for the sole purpose of increasing the intelligibility of the figures and description. For purposes of clarity, not every component may be labelled in every figure.
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DETAILED DESCRIPTION OF THE FIGURES
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[0069] The annular portion 110, a plurality of spokes 120 and the hub portion 130. The view of the vehicle wheel shown in
[0070] One characteristic feature of the vehicle wheel is that each of the plurality of spokes comprise a substantially Z-shaped cross section with a middle leg 122 and a pair of outer legs 121 and 123. Further the width of the middle leg 122 increases from the annular portion towards the hub portion 130. In this way the spoke tapers in direction to the annular portion or rim. This geometry is illustrated by the dot-dashed curved lines in
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[0072] The embodiment shown in
[0073] Moreover,
[0074] The dashed line of each cross section is parallel to the rotational axis of the wheel. That is to say the middle leg 122 is angled (a) with regard to the rotational axis of the vehicle wheel. This oblique Z-profile forms a flatter spoke with regard to the middle plane of the wheel disk than a Z-profile with a middle leg which extends parallel to the rotational axis 137 and is vertical to the middle plane of the wheel disk. In this context “wheel disc” means the part of a wheel which comprise supporting member between the axle or hub portion and the rim. Flattening the Z-shaped cross section by means of inclining the middle leg 122 as well as curving the outer legs 121, 123 towards the middle leg 122 is especially advantageous at the connection line of the annular portion, which only has a limited width.
[0075] Each of the outer legs 121, 123 comprises at least one curved portion directed towards the middle leg 122, wherein the radius (r1 see also
[0076] Sections C-C and B-B represent the mid portion of the spoke 120 and they have shorter lengths of the Z-profiles than the sections A-A and D-D. Further the length of the middle leg increases from the annular portion toward the hub portion (from section D-D—to A-A).
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[0080] Along the outer circumference of the hub portion 130 the outer legs 121, 123 of the spokes 120 form a at least partially sinusoidal connection line 136, because each outer leg of a spoke is connected to the leg of the adjacent spoke. This provides a smooth transition between the spokes 120, wherein the waveform form is limited to the section between the adjacent middle legs.
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[0082] The width t1 is less than the width t3 of the hub portion. The width t1 min is less than the maximum width of the rim of the annular portion. The annular portion 110 forms a rim with an open hollow profile in the outward radial direction, which is a modified V-shaped with curved shapes at each of the legs 111 and 112 having curved portions at each leg. Further the arrows 156 and 157 indicate that the spoke can be twisted in the case that between two adjacent spokes a vertical force 152 is applied as indicated in
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[0084] There are further torques that can be introduced into the wheel. When the wheel is accelerated or rotated a force 153 comprising one of a start-up torque, drive torque or acceleration torque occurs along the circumferences of the rim. By means of a device for braking as the disk brake 135 further opposite torques in direction of the arrow 155 can occur.
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[0086] The introduced energy (F, 152) can be efficiently dissipated by flexing and twisting the involved spoke members. That is to say the outer legs of each Z-cross section are configured to allow deflection into the direction of a curvature in order to absorb the high loads. Thereby, each of the outer legs facing each other deflect in analogy to a torsion bar spring and distribute the load of the vertical impact equally to both spokes. It is known that the flexural stress σ.sub.b (torque M/work W) of a plate spring of the height h, length I and width b can be calculated as follows:
σ.sub.b=M/W=(6*F*I)/(b*h.sup.2)
[0087] Such common formulas and formulas derived therefrom can be used in order to estimate the maximum permissible stress σ.sub.bmax, wherein in analogy to a torsion bar spring the length I of the spring corresponds to the length of the flexural member of the Z-profile.
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[0089] Further, said hollow profile includes transverse ribs 115 partitioning said hollow profile into a plurality of segments. The annular portion of the vehicle wheel of
[0090] In order to produce this complex rib 115 and rim flange 114 structure it is required to use radially arranged sliders (see arrows 118) with a collapsible core.
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[0093] Further the reference F shows the extension of a thru-axle diameter (front/rear). Diameters for front thru axles may include a range between 9 and 20 mm and including preferably 10 mm, 12 mm or 15 mm. Rear axles typically have diameters of or 12 mm. Thru axles are known for example from mountain bikes. Said thru-axle can also be combined with disc-braked cycles and is not only suited for mountain bikes but also for road bikes and electrically driven bikes.
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[0096] A side and plan view of a metal insert 139 is shown in
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[0098] With regard to the annular portion 110 of the wheel
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[0101] Further the design of the inner hub portion 130 and especially the use of the ribs 134 do not only reinforce the hub shell but can also guide the protruding counterparts 127 of the insertable component 160 into the mounted position. Further said ribs 134 allow to provide in between the rounded corners 132 of the pseudo-hexagonal hub portion (see section B-B) an air gap 164 between the outer housing of the component 160 and the inner wall of the hub portion 130. This is especially advantageous if the component 160 comprises a heat source as an electric motor such that this air volume can serve as isolation.
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[0105] In conclusion the vehicle wheel according to the invention has excellent stability characteristics and can be used in a wide field of applications including cargo cycles and electrically operated bicycles such as pedelecs and e-bikes. Since the wheel according to the invention meets high safety requirements, bicycles can be used as road cycles. In particular, the wheel is suited to be used for fleet bikes because they can be rapidly produced in one process step and in large quantities and in operation be easily maintained.
LIST OF REFERENCE NUMBERS
[0106] 100 vehicle wheel [0107] 110 annular portion [0108] 111 leg of hollow profile of rim [0109] 112 leg facing leg 111 [0110] 113 bottom of hollow profile of annular portion [0111] 114 inwardly protruding rim flange [0112] 115 rib [0113] 116 intersection point of spoke 126 with the rim [0114] 117 valve adapter [0115] 118 sliders [0116] 119 clincher tire [0117] 120 spoke [0118] 121 outer leg [0119] 122 middle leg [0120] 123 opposite outer leg [0121] 125 another spoke [0122] 126 adjacent spoke [0123] 127 protruding element for ribs 134 [0124] 128 intersection point of spoke 125 with the rim [0125] 129 plane along middle of wheel disk [0126] 130 hub portion [0127] 131 maximum radius of pseudo hexagon [0128] 132 rounded corner [0129] 133 flange [0130] 134 pair of ribs [0131] 135 disk brake [0132] 136 partially sinusoidal connection line between spoke and hub portion [0133] 137 rotational axis [0134] 138 apertures [0135] 139 metal insert [0136] 140 window in wheel disk [0137] 142 ellipse [0138] 143 holes in flange 133 [0139] 149 rotational axis [0140] 151 vertical force applied to spoke axis [0141] 152 vertical force applied between spokes [0142] 153 start-up torque, drive torque and acceleration torque [0143] 154 lateral force [0144] 155 braking torque [0145] 156 twisting of an outer leg [0146] 157 twisting of opposite outer leg [0147] 160 insertable component as e.g. electric motor with axle [0148] 161 screw [0149] 163 circumferential portion molded partially around insert 139 [0150] 164 air gap [0151] 165 rim tape [0152] 166 holes of insert [0153] 167 rotational movement [0154] 168 valve adapter [0155] 169 heat radiation [0156] 170 bilateral suspension [0157] 171 unilateral suspensions on right side [0158] 172 unilateral suspension on left side