Title of Invention

MOTORCYCLE WHEEL

Abstract

[Document Name] Abstract [Abstract] [Object] To provide a motorcycle wheel capable of absorbing an impact from, a road surface to further improve riding comfort. [Solving Means] Each two opposed spokes 47 and 48 (the positions of these spokes make an angle of 180°) with a hub 42 interposed therebetween respectively have spoke bases 4 6a placed offset in directions different from each other. Simultaneously, the spokes 47 and 48 curve to be convex in the different directions. [Selected Drawing] Fig. 3

Full Text

[Document Name] Specification [Title of the Invention] l^'GTORCYCLE WHEEL [Technical Field] [0001] The present invention relates to a motorcycle wheel used for a motorcycle. [Background Art] [O002] As a motorcycle wheel. Patent Document 1 discloses "a motorcycle two-piece wheel in which: wheel spoises integrally extending from a wheel hub positioned offset in one wheel axial direction from a central plane in the wheel-width direction curve to the other wheel axial direction; outer ends of the spokes are bent in a radial direction at positions offset in the other axial direction from the central plane in the wheel-width direction; and stepped portions formed on portions, closer to the center, of the bent outer ends are joined to a central rib of a rim". [Patent Document 1] Japanese Unexamined Utility Model Application Publication No. She 62-29901 [Disclosure of the Invention] [Problems to be Solved by the Invention] [0003] Having the spokes curved only in one direction, the motorcycle wheel described in Patent Document 1 absorbs an impact from a road surface by allowing the spokes to be deformed by the impact, and thus improves the riding comfort. However, only a lower one of the spokes is bent upon receiving the impact, and thus the rigidity of each spoke has to be increased. Moreover, when the spoke is deformed largely, the rotating surface of the wheel assembly shifts in one direction, becoming unbalance in a right-and-left direction. Thus, the technique described in Patent Document 1 has a problem of being not applicable to a wheel having long and narrow spokes. Purthermore, since the motorcycle wheel described in Patent Document 1 consists of two pieces, a tightening step of tightening the rim to the spokes is required at the time of the production, and a larger number of components are also required. Accordingly, there has been room for improvement in terms of the production cost. [0004] In order to solve the above problems, an object of the present invention is to provide a motorcycle wheel capable of absorbing an impact from a road surface to further improve riding comfort. [Means for Solving the Problems] [0005] For the purpose of accomplishing the above object, a first aspect of the present invention is characterized in that the motorcycle wheel includes a hub supported by an axle; a rim having a peripheral portion on which a tire is to be fitted; and a plurality of spokes each having an approximately U-shaped cross section, and extending in a radial direction to connect the hub to the rim. In the motorcycle wheel, the hub, the rim and the spokes are integrally casted, any one spoke of each pair of the spokes facing each other with the hub interposed therebetween has a spoke base on an inner-diameter side of the spoke, the spoke base being offset from a plane which passes through a rim center line in one axial direction of the wheel, rhe spoke extending to ourer-diameter side edges thereof while curving to be convex in the axial direction, and the other one spoke of each pair of the spokes facing each other with the hub interposed therebetween has a spoke base on an inner-diameter side of the spoke, the spoke base being offset from the plane which passes through the rim center line in the other axial direction of the wheel, the spoke extending to outer-diameter side edges thereof while curving to be convex in the other axial direction. [0006] A second aspect of the present invention is characterized in that, in a motorcycle wheel as recited to the first aspect, any one spoke of each adjacent two spokes has a spoke base on the inner-diameter side of the spoke, the spoke base being offset from the plane which passes through the rim center line in one axial direction of the wheel, the spoke extending to outer-diameter side edges thereof while curving to be convex in the axial direction, and the other one spoke of each adjacent two spokes has a spoke base on the inner-diameter side of the spoke, the spoke base being offset from the plane which passes through the rim center line in the other axial direction of the wheel, the spoke extending to outer-diameter side edges thereof while curving to be convex in the axial direction. [Effects of the Invention] [0007] In the motorcycle wheel according to the first aspect of the present invention, each pair of the spokes facing each other with the hub interposed therebetween curves in the directions different from each other. Thereby, a road-surface impact applied on one of the paired spokes can be elastically absorbed by the other one of the paired spokes curving in the opposite direction. Thus, the riding comfort can be further improved. [0008] In the motorcycle wheel according to the second aspect of the present invention, the adjacent spokes curve in the directions differenc from each other. Thereby, the adjacent spoke that curves in the different direction can prevent the rotating surface of rhe tire from shifting in the vehicle-width direction due to the deformation of the spoke. Thus, an unbalance state in a right-and-left direction can be mitigated, and the riding comfort can be improved. [Best Modes for Carrying Out the Invention] [0009] Hereinafter, preferred emibodiments of a motorcycle wheel according to the present invention will be described in detail with reference to the drawings. [0010] Fig. 1 is a side view of a motorcycle provided with the motorcycle wheel according to the present invention. A front fork 2 supports a front wheel assembly 1, and has its upper-end portions connected to a front-end portion of a mainframe 4 via a head tube 3 . The m^ainframe 4 extends in a front-rear direction of the vehicle on the center of the vehicle body, has its front portion welded to upper-end portions of a right-and-left pair of front pipes 5, and has flat portions formed on the right and left side surfaces at its rear portion. The flat portions are respectively welded to upper-end portions of a right-and-left pair of rear pipes 6 and front-end portions of a right-and-left pair of seat rails 7. [0011] The mainframe 4, the front pipes 5 and the rear oices 6 together forma cradle frame which supports a horizontal engine 8. The engine 8 is connected co a carburetor 9, which is connected to an air cleaner case 11 via a connecting tube 10. [0012] The air cleaner case 11 extends from a lower portion of the rear pipe 6 obliquely upward and rearward, and is disposed into a triangular space formed by the rear pipes 6, the seat rails 7, and a rear stay 12 connected to middle portions of the seat rails 7 that extend substantially horizontally rearward. The right and left side surfaces of the air cleaner case 11 are covered with side covers 13. [0013] A swing arm 14 has its front-end portion swingably connected to a lower portion of the rear pipe 6, and supports a rear wheel assembly 15 with its rear-end portion. Two ends of a rear cushion 17 are respectively connected to the rear-end portion of the swing arm 14 and to a side surface of a reinforcement bracket 16 welded to a side surface of the seat rail 7. [0014] Furthermore, an approximately V-shaped step holder 19 for allowing a rear step 18 to be attached thereto is provided ahead of the rear cushion 17. One end of the step holder 19 is connected to the rear stay 12 and the other end thereof shares ■ the same axis with the front-end portion of the swing arm 14, and is connected to the rear pipe 6. [0015] A dress guard 20 is provided to a portion rear of the rear cushion 17 located on upper of the left side surface of the rear ) v;heel assembly 15 . An upper-end portion of a side-surface frame 21 of the dress guard 20 has its top end portion supported by a bracket 22 and has its rear portion supported by a bracket 23. One end of the bracket 22 is tightened to an upper-end portion of the rear cushion 17 to be attached thereto, and the other end thereof extends rearward, and supports the upper-end portion of the side-surface frame 21. [0016] A lower-end portion of the side-surface frame 21 is connected to a rear-end portion of a lower-portion frame 25 with a bracket 24 . The lower-portion frame 25 extends forward while crossing the rear cushion 17 from the outside, and has its top-end portion connected to a bracket 26 attached to an edge portion of the step holder 19 that supports the rear step 18, while considerably overhanging sideward. [0017] Note that, as shown in Fig. 1, a fuel tank 24 is supported on the mainframe 4, and a seat 28 is supported on the seat rails 7. The vehicle body includes other main components except for those described so far: a front cowl 29 covering a front upper portion of the front fork 2; a rectangular guard pipe 30 attached to the front pipes 5 and overhanging in a vehicle-width direction; a handlebar 31 for allowing the front fork 2 to rotate; an unillustrated brake pedal provided at the right side of the vehicle body; steps 32 provided to both of the right and left side portions of the vehicle body; an exhaust pipe 33 extending rearward from the engine 8; an unillustrated muffler connected to a rear-end portion of the exhaust pipe 33; a change pedal 54 provided to the left side of the vehicle body; and the like. The dress guard 20 and the muffler are disposed as being assigned to "he right and left sides of the vehicle body which is thus sandwiched rherebetween. [G0i8] (First embodiment) Fig. 2 and Fig. 3 show a first embodiment of the present invention- Fig. 2 is a perspective view of a motorcycle wheel according to the present invention. Fig. 3 is a cross-sectional view of the motorcycle wheel according to the present invention. Fig. 4 is an explanatory drawing for explaining effects of the motorcycle wheel according to the present invention - The motorcycle wheel of this first embodiment is used as a front wheel of the motorcycle of Fig. 1. [0019] The front wheel assembly 1 includes a front wheel 40 and a tire 41 fitted on this front wheel 40. As shown in Fig. 2 and Fig. 3, the front wheel 40 includes; a hub 42 supported by an axle 35; and a rim 44 having its peripheral portion on which the tire 41 is fitted; and multiple spokes 45, ,.., 46 extending outward in radial directions from the hub to connect the hub to the rim. The hub A2. the rim A4, and the spokes 46, ..., 45 are integrally casted. [0020] The hub 42 includes: a cylindrical inner hub 42a provided on the axle side; a cylindrical outer hub 42b provided outside the inner hub in a radial direction; and a side wall 43 connecting one end portion of the inner hub 42a to that of the outer hub 42b. The side wall 43 is formed being inclined invjardly in the axial direction from the portion connected to the inner hub 42a as approaching the outer side in the radial direction. Additionally, formed are bolt holes 42c are formed into which bolts for attaching unillustrated braking means are screwed at end portions of the outer hub 42b that is located on an opposite side to an end portion where the side vjall 43 is formed. Incidentally, the braking means may be a disc brake or a drum brake. Moreover, the multiple spokes 46, ,.., 46 extend outward in the radial directions from a peripheral portion of the outer hub 42b. [0021] The rim 44 is in a cylindrical shape, and connected to the outer end of each of the spokes 46, .-., 46. The tire 41 is fitted on the peripheral portion of the rim 44. [0022] Each of the spokes 46, ..., 46 has a cross section in an approximately U shape being open to either one of sides in the axial direction. Each spoke 46 has its spoke base 46a jointed to the peripheral portion of the hub 42, the spoke base 4 6a being on an inner-diameter side of the spoke 46. The spoke 46 is connected to the rim 44 via the outer-diameter side edge thereof, [0023] In this embodiment, six spokes 46, ,.., 46 are provided. Among these, three first spokes 47, 47, 47 are arranged at intervals of 120° in a circumferential direction. .As shown in Figs. 2 and 3, the spoke bases 4 6a of the first spokes 47, ^7, 47 are offset, on the left side in the drawing of the front wheel 40, from a plane which passes through a rim center line CL extending in the radial direction, the line connecting axial-direction central portions of the rim 44. Simultaneously, the first spokes 47, 47, 47 extend to the cuter-diair.eter side edge while curving to be convex on the left side. The first spokes 47, 47, 47 are formed so that concave portions thereof may be opened to the right side in the drawing. The opened end portion of the concave portion is positioned on the opposite side (i.e., right side in the drawing), in the curving direction, in relation to the plane which passes through the rim center line CL. Remaining three second spokes 48, 48, 48 are arranged at intervals of 120° in the circumferential direction and being apart by 60° from the three first spokes 47, 47, 47. The spoke bases 46a of the second spokes 48, 48, 48 are offset on the right side, in the drawing, of the front wheel 40 from the plane which passes through the rim center line CL. Simultaneously, the second spokes 48, 48, 48 extend to the outer-diameter side edge while curving to be convex on the right side. The second spokes 48, 48, 48 are formed so that concave portions thereof may bs opened to the left side in the drawing. The opened end portions of the concave portions are positioned on the opposite side, the curving direction (i.e., left side in the drawing), in relation to the plane which passes through the rim center line CL. [0024] Thus, the spokes 47, 48 facing each other with the hub 42 interposed therebetween (that is, 180° apart from each other) have their corresponding spoke bases 46a offset in the directions different from each other, and curved to be convex in the directions different from each other. Moreover, either one of the adjacent spokes 47, 48 has its spoke base 46a offset in an axial direction of the front wheel 40 from the plane which passes through the rim center line CL. Sim.ultaneously, the one of rhe adjacent spokes 47, 48 curves to the outer-diameter side edge to be convex in an axial direction. Meanwhile, the other one of the adjacent spokes 48, 47 has its spoke base 4 6a on the inner-diameter side offse^ in the other axial direction of the front wheel 40 from the plane which passes through the rim center line CL. Simiultaneously, the other one of the adjacent spokes 47, 48 curves to the outer-diameter side edge to be convex in the other axial direction. [0025] In short, in the front wheel 40 of this embodiment, The multiple spokes 46, ..., 46 are arranged so that the spokes 47, 48 facing each other with the hub 42 interposed therebetween are arranged with their curving directions directed opposite to each other, and that the curving directions of the adjacent spokes 47, 48 may be directed opposite to each other. [0026] Additionally, swollen portions 46b, 45b, 4 6b are formed on the first spokes 47, 47, 47 being offset on a side where the side wall 43 is provided, the side wall connecting the one end portion of the inner hub 42a of the hub 42 to that of the outer hub 42b. The swollen portions 46b, 46b, 4 6b are parts of the spoke bases 46a, 46a, 46a swelling toward the center of the front wheel on the surfaces of the side walls 43, and are formed continuously from the surface of the first spokes 47, 47, 47. Each swollen portion 4 6b is formed to be inclined outward in the axial direction as the side wall 43 provided in the hub 42 approaches the center. Thus, the swollen portion 46b forms a substantially triangular concave-convex shape on the side wall 4 3 when vievjed from the front. [0027] Hereinafter, effects of the miotorcycle wheel according tc the present invention will be described with reference to Ij w Fig. 3 and Fig. 4. When an impact force is applied from a road surface to the bottC'in surface of the front vjheel 40 according to the present invention through an unillustrated tire, a force in an upward direction acts on the first spoke 47 of the front heel 40. Accordingly, the first spoke 47 is bent in an arrow 1 direction, and the rim 44 shifts in the arrow 1 direction. Thereby, a force F in an obliquely upward direction of the rim 44 acts on the second spoke 48 facing the first spoke 47 with the hub 42 interposed therebetween through the annular rim 44. In other words, while the second spoke 48 is pulled upward, a component force of the force F in the axial direction acts in an arrow 2 direction that is the direction opposite to the curving of the first spoke 47. In this respect, in a conventional wheel in which spokes facing each other with a hub interposed therebetween are curved in the same direction, the upper spoke facing the other spoke with the hub interposed therebetween receives a force in the curving direction. The curving of the spoke acts as resistance by itself, and accordingly an impact force cannot be absorbed with the elastic forced produced by the bending of the spoke. In contrast, in the front wheel 40 according to the present invention, the second spoke 48 facing the first spoke 47 with the hub 42 interposed therebetween curves in the opposite direction to that of the first spoke 47. Thus, the component force in the axial direction, acting in the arrow 2 direction, of the force F acting obliquely utJward can be absorbed by an elastic force o f the deformation of the second spoke 48 in the arrow 2 direction. i hereby, both of the first and second spokes 47, 48 absorb the impact frorr, the road surface, ailowing the riding comfort to be improved. Moreover, since both the first and second spokes 47, 48 facing each other with the hub 42 interposed therebetween can absorb the road-surface impact, the strengths of the first and second spokes 47, ^3 3 can be reduced in comparison with the conventional wheel. This makes it possible to adopt a wheel including long and narrow spokes. [0028] Moreover, as described above, when an impact force is applied from a road surface to the bottom surface of the front wheel 40 through the unillustrated tire, the force G in the upward direction acts on the first spoke 47 of the front wheel 40. The first spoke 47 is deformed in the arrow 1 direction, and the rim 44 shifts in the arrow 1 direction. At this point, since the adjacent second spoke 48 curves in the opposite direction to the first spoke 47, the curving of the second spoke acts as resistance by itself against the shift in the arrow 1 direction due to the bending of the first spoke. Thereby, a force for reducing the shift in the arrow 1 direction acts in an arrow 3 direction that is opposite to the arrow 1 direction. [0029] In this manner, the adjacent first and second spokes 47, 48 are arranged so that the curving directions thereof may be in the opposite directions to each other. Accordingly, the adjacent second and first spokes 48, 47 can prevent the excessive shift, in the vehicle-width direction, of the tire rotating surface due to the bending of the first and second spokes 47, 48, which is caused by the road-surface impact. In other words, with the use of the elasticity owing to the curving of the first and second spokes 47, 48 facing each other with the hub 42 interposed therebetween, the excessive shift of the adjacent second and first spokes 48, 47 can be prevented. Thereby, an unbalance state in a right-and-left direction is mitigated, and the riding com.fort can be improved. [0030] Additionally, the swollen portions 4 6b, 4 6b, 46b are formed in the first spokes 47, 47, 47 in a way that the spoke bases 46a, 46a, 46a are swollen toward the center of the front wheel 40 on the surface of the side wall 43. Accordingly, joint portions between the spokes 47, 47, 4 7 and the hub 42 can increase its strength with a three-dimensional configuration, the joint portion being applied the maximum stress when the spokes 47, 47, 47 are deformed. [0031] (Second embodiment) Fig. 5 and Fig. 6 show a second embodiment of the present invention. Fig. 5 is a perspective view of a motorcycle wheel according to the present invention . Fig . 5 is a cross-sectional view of the motorcycle wheel according to the present invention. The motorcycle wheel of this second embodiment is used as a rear wheel of the motorcycle of Fig. 1. Note that, in the drawing, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. [0032] The rear wheel assembly 15 includes a rear wheel 50 and a tire 51 fitted on the rear wheel 50. The rira 44 and the spokes 46, ..., 46 of the rear wheel 50 are the same as those of the front wheel 40 shown in the first embodiment, and the description thereof will be omitted. [0033] As shown in Fig. 5 and Fig. 6, a hub 52 includes: a cylindrical inner hub 52a provided on the axle side; a cylindrical outer hub 52b provided outside the inner hub 52a in a radial direction; and an intermediate wall 53 connecting the inner hub 52a and the outer hub 52b at the middle portions of the inner hub 52a and the outer hub 52b in the axial direction. At a peripheral portion of the inner hub 52a positioned on the left side, in the drawing, of the intermediate wall 53, a chain 35 for transmitting power from the engine 8 to the rear wheel assembly 15 is formed to support a gear 37 from which the chain 36 is suspended. In addition, into a space formed between the inner hub 52a and the outer hub 52b positioned on the right side, in the drawing, of the intermediate wall 53, unillustrated braking means, a drum brake for example, is attached. Note that, since the spokes 46, ..., 46 are jointed to the outer hub 52b at their middle portions in the axial direction, the swollen portion 4 55 provided in the front wheel 40 of the first embodiment is not provided. [0034] The spokes 46, -,, 46 of the rear wheel 50 have the same structure as that of the front wheel 40 of the first embodiment except that the swollen portions 46b, 46b, 4 6b are not provided. Accordingly the rear wheel 50 has the same effects as those of the front wheel 40 of the first embodiment. [0035] It should be noted that the present invention is not limited to the above-described embodiments. Modification, improvement, and the like can be made as appropriate. For example, the number of the spokes 46, ,.., 4 6 is not limited to six, and the number can be modified according to the specification appropriately. [Brief Description of the Drawings] [0036] [Fig. 1] Fig. lis a side viewofa motorcycle provided with a motorcycle wheel according to the present invention. [Fig. 2] Fig. 2 is a perspective view of a motorcycle wheel (front wheel) according to a first embodiment of the present invention. [Fig. 3] Fig. 3 is a cross-sectional view of the motorcycle wheel (front wheel). according to the first embodiment of the present invention. [Fig. 4] Fig. 4 is an explanatory drawing for explaining effects of the motorcycle wheel (front wheel) according to the first embodiment of the present invention. [Fig. 5] Fig. 5 is a perspective view of a motorcycle wheel (rear wheel) according to a second embodiment of the present invention. [Fig, 6] Fig. 5 is a cross-sectional view of the motorcycle wheel (rear wheel) according to the second embodiment of the present invention. [Explanation of the Reference Numerals] [0037] 1 FRONT WHEEL ASSEMBLY 15 REAR WHEEL ASSEMBLY 40 FRONT WHEEL (MOTORCYCLE WHEEL) 50 REAR WHEEL (MOTORCYCLE WHEEL) 42, 52 HUB 4 3 SIDE WALL 4 4 RIM 4 5 SPOKE 463 SPOKE BASE 4 6b 48 SWOLLEN PORTION FIRST SPOKE SECOND SPOKE FIG. 3 ARROW 1 ARROW 2 FIG. 4 ARROW 1 ARROW 2 ARROW 3 [Documer.t Name] Scope of Claims [Claim 1] A motorcycle wheel including: a hub supported by an axle; a rim having a peripheral portion on which a tire is to be fitted; and a plurality of spokes each having an approximant one spoke of each pair of the spokes facing each other with the hub interposed therebetween has a spoke base on an inner-diameter side of the spoke, the spoke base being offset from a plane which passes through a rim center line in one axial direction of the wheel, the spoke extending to outer-diameter side edges thereof while curving to be convex in the axial direction, and privately U-shaped cross section, and extending in a radial direction to connect the hub to the rim, wherein the hub, the rim and the spokes are integrally casted, the other one spoke of each pair of the spokes facing each other with the hub interposed therebetween has a spoke base on an inner-diameter side of the spoke, the spoke base being offset from the plane which passes through the rim center line in the other axial direction of the wheel, the spoke extending to outer-diameter side edges thereof while curving to be convex in the other axial direction. [Claim 2) The motorcycle wheel according to claim 1, wherein any one spoke of each adjacent two spokes has a spoke base on the inner-diameter side of the spoke, the spoke base being offset from the plane which passes through the rim center line in one axial direction of the wheel, the spoke extending to outer-diameter side edges thereof while curving to be convex in the axial direction, and the other one spoke of each adjacent two spokes has a spoke base on the inner-diameter side of the spoke, the spoke base being offset from the plane which passes through the rim center-line in the other axial direction of the wheel, the spoke extending to outer-diameter side edges thereof while curving to be convex in the axial direction.

Documents:

426-CHE-2009 CORRESPONDENCE OTHERS 24-10-2014.pdf

426-CHE-2009 DESCRIPTION (COMPLETE) 26-02-2009.pdf

426-CHE-2009 DRAWINGS 26-02-2009.pdf

426-CHE-2009 FORM-1 16-10-2014.pdf

426-CHE-2009 FORM-1 26-02-2009.pdf

426-CHE-2009 FORM-18 26-02-2009.pdf

426-CHE-2009 FORM-3 26-02-2009.pdf

426-CHE-2009 FORM-5 26-02-2009.pdf

426-CHE-2009 OTHERS 26-02-2009.pdf

426-CHE-2009 POWER OF ATTORNEY 26-02-2009.pdf

426-CHE-2009 AMENDED CLAIMS 01-09-2014.pdf

426-CHE-2009 CORRESPONDENCE OTHERS 16-10-2014.pdf

426-CHE-2009 EXAMINATION REPORTS RECIEVED 01-09-2014.pdf

426-CHE-2009 FORM-3 01-09-2014.pdf

426-che-2009 abstract.pdf

426-che-2009 claims.pdf

426-CHE-2009 CORRESPONDENCE OTHERS 26-08-2009.pdf

426-che-2009 correspondence others.pdf

426-CHE-2009-Petition for POR.pdf