Vehicle wheel

A vehicle wheel of the present invention, includes: a sub air chamber member which serves as a Helmholtz resonator and is fixed to an outer circumferential surface of a well portion in a tire air chamber; a first standing wall surface formed such as to stand from the outer circumferential surface of the well portion outward in radial direction and extend in circumferential direction of the outer circumferential surface; and a second standing wall surface formed on the well portion such as to face the first standing wall surface in width direction of the outer circumferential surface.

TECHNICAL FIELD

The present invention relates to a vehicle wheel.

BACKGROUND ART

Conventionally, as a wheel that reduces the road noise caused by air column resonance in the air chamber of a tire, there are presented various wheels provided with Helmholtz resonators each having a sub air chamber communicating with the air chamber of a tire through a communication hole. As such a vehicle wheel, desirable is a vehicle wheel that has a structure in which a Helmholtz resonator (a sub air chamber member) can be easily and firmly attached to the outer circumferential surface of the well portion. In this situation, as disclosed for example by Patent Literature 1, the inventor has already presented a vehicle wheel with a structure that includes a sub air chambers on the inner side of a main body portion formed by an upper plate and a bottom plate, wherein the main body portion is attached to the outer circumferential surface of a well portion through the plate-shaped edge or fringe portions respectively extending from the respective sides of this main body portion.

In more detail, this vehicle wheel is provided with a pair of standing wall surfaces formed such as to extend along the circumferential direction of the outer circumferential surface of the well portion, and the main body portion is disposed substantially at the center between the standing wall surfaces facing each other. The respective tip ends of the edged portions extending from the main body portion are engagingly fixed to the respective standing wall surfaces.

RELATED ART DOCUMENT

Patent Literature

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

In a conventional vehicle wheel (for example, see Patent Literature 1), the above-described communication hole of a Helmholtz resonator protrudes from a main body portion having a sub air chamber. This communication hole is formed inside a protruding portion formed for example by a tube member. Particularly, in a vehicle wheel (for example, see FIG. 9B of Patent Literature 1) in which a main body portion is longitudinal in the circumferential direction of the wheel and the protruding portion is arranged such as to protrude from the end portion, with respect to the circumferential direction, of the main body portion, the communication hole is arranged substantially at the central portion along the wheel width direction of the sub air chamber member, in other words, substantially at the middle position between the both standing wall surfaces.

FIG. 7referred to in the following is a partial enlarged perspective view in the vicinity of the protruding portion of a sub air chamber member of a conventional vehicle wheel.

As shown inFIG. 7, a sub air chamber member10of this vehicle wheel is provided with a main body portion13which is longitudinal in the wheel circumferential direction X, and a tube body18arranged such as to protrude from the end portion, with respect to the wheel circumferential direction X, of the main body portion13.

Incidentally, the main body portion13is provided with an upper plate25aand a bottom plate, not shown, arranged on the side (the rear side of the sheet ofFIG. 7) opposite to the upper plate25a. A sub air chamber (not shown) is formed between the upper plate25aand the bottom plate (not shown). A communication hole18aformed inside the tube body18communicates with this sub air chamber.

The tip ends of both edge portions14a,14bextending along wheel width direction Y from the main body portion13are engagingly fixed to the first and second standing wall surfaces16a,16b(schematically shown by virtual lines inFIG. 7) formed on the outer circumferential surface of the well portion (not shown).

The sub air chamber member10is provided with an extending portion14cof a plate-shaped body, the extending portion14cextending from the end portion of the main body portion13along the wheel circumferential direction X. The extending portion14cis in a curve-shape convex on the outer circumferential surface of the well portion. The both ends of the extending portion14care engagingly fixed to the first and second standing wall surfaces16a,16b.

InFIG. 7, symbols33arepresent joint portions joining the upper plate25aand the bottom plate, wherein the upper plate25ais partially recessed toward the bottom plate (not shown).

The shaded portions categorized in three kinds by gray scale represent the state of deformation of the sub air chamber member10due to the centrifugal force generated at the maximum assumed rotational speed of the wheel, as deformation amount distribution. Incidentally, the deformation amount herein was obtained by a simulation testing by CAE (Computer Aided Engineering). The darkest shaded portion10aout of these shaded portions represents the region with the largest deformation amount (lifted degree) from the outer circumferential surface of the well portion to the centrifugal direction. The shaded portion10b, which is the second-darkest after the darkest shaded portion10a, represents the region with a medium deformation amount (lifted degree). The palest shaded portion10crepresents the region with a small deformation amount (lifted degree). The hollow portion10drepresents the region with little deformation.

In a sub air chamber member10of such a conventional vehicle wheel, as shown inFIG. 7, the deformation amounts of the end portion, with respect to the wheel circumferential direction X, of the main body portion13and the extending portion14care the largest due to the centrifugal force during rotation of the wheel. In other words, little deformation occurs on the sub air chamber member10in the vicinity of the both tip ends of the edged portions14a,14b, which are engagingly fixed to and strongly constrained by the first and second standing wall surfaces16a,16b(see the hollow portion10d). However, the closer to the central portion in the wheel width direction Y from the both tip ends of the edged portions14a,14bengaged to the first and second standing wall surfaces16a,16b, the larger the deformation amount of the sub air chamber member10from the shaded portions10c,10bto the darkest shaded portion10a.

Incidentally, although not shown, in comparison with a sub air chamber member with assumption that a tube body18is not arranged at the end portion of the main body portion13, the deformation amount in the centrifugal direction of the portion formed by integration of the tube body18and the extending portion14cof the sub air chamber member10, shown inFIG. 7, increased by 33%. The deformation amount (the length of displacement in the direction perpendicular to the surface at the position Q) of the bottom plate (not shown) at the position Q increased by 64%. The deformation amount (the length of displacement in the direction perpendicular to the surface at the position R) of the upper plate25aat the position R increased by 70%.

In the sub air chamber member10of such a conventional vehicle wheel, the tube body18which acts to increase the mass factor of the centrifugal force (F=mrω2: where m is the mass, r is the radius, and ω is the angular speed) is disposed at the central portion, with respect to the wheel width direction Y, of the main body portion13, the central portion being distant from the edged portions14a,14bfirmly constrained by the first and second standing wall surfaces16a,16b. This is also a cause of increasing the deformation amount. This increase in the deformation amount releases the engaging fitting of the both edge portions14a,14bto the first and second standing wall surfaces16a,16b. Further, the increase in the deformation amount significantly decreases the critical rotational speed, of the wheel, that detaches the sub air chamber member10from the well portion.

In this situation, an object of the invention is to provide a vehicle wheel that allows setting the critical rotational speed of the wheel higher than the critical rotational speed of a conventional vehicle wheel whose protruding portion forming a communication hole is disposed at the end portion, with respect to the wheel circumferential direction, of a sub air chamber member.

Means for Solving the Problems

For solution of the above-described problems, according to the present invention, a vehicle wheel includes: a sub air chamber member which serves as a Helmholtz resonator and is fixed to an outer circumferential surface of a well portion in a tire air chamber; a first standing wall surface formed such as to stand from the outer circumferential surface of the well portion outward in radial direction and extend in circumferential direction of the outer circumferential surface; and a second standing wall surface formed on the well portion such as to face the first standing wall surface in width direction of the outer circumferential surface, wherein the sub air chamber member includes: a main body portion longitudinal in the circumferential direction, the main body portion including a bottom plate disposed on the outer circumferential surface side of the well portion, and an upper plate forming a sub air chamber between the upper and and bottom plates; edge portions that join the bottom plate and the upper plate at both side portions, with respect to the width direction, of the main body portion, and are engagingly fixed to respective groove portions formed on the first standing wall surface and the second standing wall surface; and a protruding portion that is arranged such as to protrude from an end portion with respect to the longitudinal direction of the main body portion, in the circumferential direction, and is provided inside thereof with a communication hole for communication between the sub air chamber and the tire air chamber, and wherein the protruding portion is arranged being biased in the width direction of the main body portion from a central portion to a side of either of the edge portions.

This vehicle wheel is provided with a protruding portion that is engagingly fixed to either of the first standing wall surface and the second standing wall surface, wherein the protruding portion is biased to the end portion firmly constrained to the either of these standing wall surfaces. Thus, this vehicle wheel can more effectively prevent the deformation of a sub air chamber member when a centrifugal force is applied to the protruding portion unlike a conventional vehicle wheel (for example, see FIG. 9B of Patent Literature 1) in which a protruding portion is disposed at the central portion, with respect to the width direction, of a main body portion.

Further, it is preferable that this vehicle wheel includes: an extending portion formed by a plate shaped body extending from end portions, with respect to wheel circumferential direction, of the main body portion and the end portions, wherein the protruding portion is formed in integration with the extending portion.

This vehicle wheel makes it possible to reduce the deformation of the protruding portion itself being supported by the extending portion. Thus, the vehicle wheel realizes a stable silencing function.

In this vehicle wheel, the protruding portion is preferably formed such as to protrude in the wheel circumferential direction further than an end portion, with respect to the wheel circumferential direction, of the extending portion.

In this vehicle wheel, the extending portion is further back than the protruding portion toward the main body portion, forming a step. As a result, the stiffness of the extending portion is increased so that the deformation of the sub air chamber member, at the time when a centrifugal force is applied to the protruding portion, is further effectively prevented.

In this vehicle wheel, the communication hole preferably has a cross-sectional shape longitudinal in wheel radial direction.

In such a vehicle wheel, as the communication hole is longitudinal in the wheel radial direction, it is possible to arrange the protruding portion, the protruding portion being provided with the communication hole, with a bias to the edge portion. Thus, this vehicle wheel further more effectively prevents the deformation of the sub air chamber member when a centrifugal force is applied to the protruding portion.

In this vehicle wheel, the communication hole is preferably in a tongue shape that is longitudinal.

In such a vehicle wheel, as the tip end of a tongue shape, in a cross-sectional view, of the communication hole has a curved shape. Thus, the stiffness of the protruding portion itself including this communication hole therein is increased. As a result, the deformation, at the time when a centrifugal force is applied to the protruding portion, can be further effectively prevented.

In this vehicle wheel, it is preferable that: the first standing wall surface is formed on an annular standing wall standing at the well portion; wherein the sub air chamber member includes a rotation preventing member that protrudes in wheel width direction from the either of the edge portions to prevent the sub air chamber member from deviating in the wheel circumferential direction by that the rotation preventing member is fitted into a cut-away portion formed on the standing wall; and wherein the protruding portion is formed, being biased to the edge portion on which the rotation preventing member is formed.

In such a vehicle wheel, when the sub air chamber member is attached to the rim, the rotation preventing member is fitted to the cut-away portion and the edge portion on the side of this rotation preventing member is engagingly fixed to the first standing wall surface. Then, the edge portion on the side opposite to this end portion is pressed toward the rim, and this edge portion is engagingly fixed to the second standing wall surface.

In this vehicle wheel, as the protruding portion is formed, being biased to the edge portion where the rotation preventing member is formed. Accordingly, when the edge portion on the side opposite to this edge portion is pressed toward the rim, the sub air chamber member can be easily attached to the rim without disturbance by the protruding portion in this pressing.

In this vehicle wheel, the sub air chamber member is preferably formed from a resin.

This vehicle wheel makes it possible to realize reduction in weight, improvement of mass productivity, reduction in manufacturing cost, ensuring air tightness of the sub air chamber, and the like of the sub air chamber member.

Advantages of the Invention

In comparison with a conventional vehicle wheel in which a protruding portion forming a communication hole is disposed at the end portion, with respect to the wheel circumferential direction, of a sub air chamber member, a vehicle wheel according to the invention makes it possible to effectively prevent the deformation of a sub air chamber member caused when a centrifugal force is applied to a protruding portion. Thus, for a vehicle wheel according to the present invention, the critical rotational speed of the wheel can be set to a higher speed than for a conventional wheel.

EMBODIMENT FOR CARRYING OUT THE INVENTION

An embodiment according to the present invention will be described below in detail, referring to the drawings appropriately.

FIG. 1is a perspective view of a vehicle wheel1according to an embodiment of the present invention.

As shown inFIG. 1, the vehicle wheel1in this embodiment includes a plurality of sub air chamber members10, which serve as Helmholtz resonators, at equal intervals along the wheel circumferential direction X. Although a vehicle wheel having four sub air chambers10is shown in this embodiment, a vehicle wheel according to the present invention may have two, three, or more than four sub air chamber members10.

The vehicle wheel1in this embodiment is primarily featured by that a tube body18having a later-described communication hole18a(seeFIG. 2) inside the tube body18is formed such as to be biased to a later-described edge portion14a(seeFIG. 2) from the central portion, with respect to the wheel width direction Y, of the sub air chamber member10.

Herein, the entire configuration of the vehicle wheel1will be first described.

The vehicle wheel1in this embodiment is provided with a rim11and a disc12for connecting the rim11to a hub (not shown). InFIG. 1, symbol11drepresents the outer circumferential surface of a well portion11c, and a sub air chamber member10is fitted into the well portion11c, as described later in detail. Further, symbol15represents an annular standing wall standing at the outer circumferential surface11dof the well portion11csuch as to extend along the circumferential direction of the rim11. Incidentally, the sub air chamber member10is as described later engagingly fixed to the standing wall15. Symbol15arepresents a cut-away portion, of the standing wall15, into which a rotation preventing member19is fitted when the sub air chamber member10is engagingly fixed to the standing wall15.

FIG. 2is an entire perspective view of a sub air chamber member10.

The sub air chamber member10is a member which is longitudinal in one direction (wheel circumferential direction X), as shown inFIG. 2, and is provided with a main body portion13, a tube body18, edged portions14a,14b, and extending portions14c,14d.

Incidentally, the tube body18corresponds to ‘protruding portion’ set forth in claims.

The main body portion13is longitudinally formed such as to curve, matching the curvature along the circumferential direction of the outer circumferential surface11d(seeFIG. 1), and has a sub air chamber SC (seeFIG. 3) inside thereof, as described later.

The tube body18is arranged such as to protrude in the wheel circumferential direction X from the end portion with respect to the longitudinal direction (the end portion with respect to the wheel circumferential direction X) of the main body portion13, in other words, in the circumferential direction of the outer circumferential surface11d(seeFIG. 1).

The tube body18is arranged such as to be biased to the edge portion14afrom the center line10fwith respect to the wheel width direction Y of the main body portion13, in other words, the width direction of the outer circumferential surface11d(seeFIG. 1).

The communication hole18ais formed inside the tube body18. The communication hole18amakes the sub air chamber SC (seeFIG. 3) inside the main body portion13and a later-described tire air chamber MC (seeFIG. 3) communicate with each other.

The cross-sectional shape of the communication hole18ais preferably a cross-sectional shape, which is longitudinal in wheel radial direction Z (seeFIG. 3).

As described above, although the tube body18having such a communication hole18ais biased to the edge portion14ain this embodiment, it is also possible according to the invention to make an arrangement such that the tube body18is biased to the edge portion14b.

The edge portion14aand the edge portion14bare formed along the respective side portions, with respect to the wheel width direction Y, of the main body portion13, and extend in the wheel circumferential direction X. The edge portions14a,14bare engagingly fixed respectively to the first standing wall surface16a(seeFIG. 3) and the second standing wall surface16b(seeFIG. 3). The first standing wall surface16ais formed on the annular standing wall15standing from the well portion11c(seeFIG. 1). The second standing wall surface16bis formed on the well portion11c, facing the first standing wall surface16ain the wheel width direction Y. The edge portion14aand the edge portion14bare engagingly fixed respectively to a groove portion17a(seeFIG. 3) formed on the first standing wall surface16aand a groove portion17b(seeFIG. 3) formed on the second standing wall surface16bto thus fix the main body portion13to the well portion11c.

The extending portion14cand the extending portion14dare formed by integrating the plate-shaped body portion extending in the wheel circumferential direction X from the end portion, with respect to the wheel circumferential direction X, of a later-described bottom plate25b(seeFIG. 3) of the main body portion13, and plate-shaped portions extending in the wheel circumferential direction X from the end portions, with respect to the wheel circumferential direction X, of the edge portions14a,14b. Incidentally, the extending portions14c,14dare located on an extension, in the wheel circumferential direction X, of the edge portions14a,14b, being curved to match the curvature, with respect to the circumferential direction, of the outer circumferential surface11d(seeFIG. 1).

Incidentally, symbol19represents a rotation preventing member for preventing the sub air chamber member10from deviation along the wheel circumferential direction X by that the rotation preventing member19is fitted into the cut-away portion15a(seeFIG. 1) of the standing wall15(seeFIG. 1) when the sub air chamber member10is fixed to the outer circumferential surface11d(seeFIG. 1) of the well portion11c(seeFIG. 1). The rotation preventing member19is formed by a piece formed in a rectangular shape in a plan view formed such as to protrude from the edge portion14ain the wheel width direction Y.

FIG. 3referred to below is a cross-sectional view of the sub air chamber member10disposed on the well portion11c, and is a partial enlarged cross-sectional view taken along the line III-III inFIG. 1.

As shown inFIG. 3, the main body portion13of the sub air chamber member10is provided with a bottom plate25band an upper plate25aforming a sub air chamber SC between the upper and bottom plates25a,25b. Incidentally, although the upper and bottom plates25a,25bhave the same thickness in this embodiment, the upper and bottom plates25a,25bmay have different thicknesses respectively.

The upper plate25aforms the sub air chamber SC by curving such as to have a bulge above the bottom plate25bdisposed along the outer circumferential surface11dof the well portion11c.

The upper plate25ais provided with upper joint portions33aat the part that constructs the main body portion13. These upper joint portions33aare formed such that the upper plate25ais partially recessed toward the sub air chamber SC, and are in a circular shape in plan view. As shown inFIG. 2, these upper joint portions33aare formed in a quantity of eight such as to be arrayed in a line of the center line10fof the main body portion13, along the longitudinal direction (wheel circumferential direction X) of the sub air chamber member10.

Returning again toFIG. 3, the bottom plate25bis provided with bottom-side joint portions33bat the positions corresponding to the upper joint portions33a.

These bottom-side joint portions33bare formed such that the bottom plate25bis partially recessed toward the sub air chamber SC, and are in a circular shape in a plan view. These bottom-side joint portions33bare integrated at the tip end portions thereof with the tip end portions of the upper joint portions33aof the upper plate25ato thus join the upper and bottom plates25a,25b.

Incidentally, in the present invention, it is also possible to arrange a structure without such upper joint portions33aand bottom-side joint portions33b.

FIG. 4referred to below is a cross-sectional perspective view of the sub air chamber member10cut off by line IV-IV inFIG. 2.

As shown inFIG. 4, the upper joint portions33aand the bottom-side joint portions33bjoined with each other in the sub air chamber SC have a structure that improves the mechanical strength of the sub air chamber member10and also enables greater effect on a later-described silencing function by reducing variation in the inner volume of the sub air chamber SC.

The inner volume of the sub air chamber SC is preferably 50-250 cc approximately. By setting the inner volume of the sub air chamber SC in this range, the sub air chamber member10can have sufficient effect on silencing and meanwhile enables reduction in the weight of the vehicle wheel1(seeFIG. 1) by inhibiting an increase in the weight thereof. Further, the length of the sub air chamber member10along the wheel circumferential direction X (seeFIG. 2) can be appropriately set in consideration of adjusting the weight of the vehicle wheel1and easiness in attaching to the well portion11c, with the length of a half of the circumferential length (the circumferential length of the outer circumferential surface11d(seeFIG. 1) of the well portion11c(seeFIG. 1)) of the rim11(seeFIG. 1) as the maximum length.

Incidentally, inFIG. 4, symbol13represents the main body portion, symbol25arepresents the upper plate, and symbol25brepresents the bottom plate.

Returning toFIG. 3again, the communication hole18afor communication between the tire air chamber MC and the sub air chamber SC is as described above has a cross-sectional shape longitudinal in the wheel radial direction Z. Concretely, inFIG. 3, as shown by virtual lines (alternate long and two short dashes lines), the cross-sectional shape of the communication hole18ais wider on the bottom plate25b, and tapers from the bottom plate25btoward the outside in the wheel radial direction Z. Although the communication hole18apreferably has a cross-sectional shape that is longitudinal in the wheel radial direction Z, the communication hole18amay have a different cross-sectional shape such as a polygonal shape instead of a longitudinal shape. Incidentally, the cross-sectional area of the communication hole18apreferably has a diameter larger than or equal to 5 mm if converted into a circular shape with the same cross-sectional area.

The length of a communication hole18ais set such as to satisfy an expression for obtaining a resonant vibration frequency of a Helmholtz resonator, the expression being described by the following Expression 1.
f0=C/2π×√(S/V(L+α×√S))  Expression 1

C (m/s): sonic speed inside sub air chamber SC (=sonic speed inside tire air chamber MC)

V (m3): inner volume of sub air chamber SC

L (m): length of communication hole18a

S (m2): cross-sectional area of opening portion of communication hole18a

α: correction factor

Incidentally, the resonant vibration frequency f0is matched to the resonant vibration frequency of the tire air chamber MC.

The tube body18having such a communication hole18ain this embodiment is preferably formed, as shown inFIG. 2, such as to protrude in the wheel circumferential direction X further than the end portion, with respect to the wheel circumferential direction X, of the extending portion14c.

The tip ends of the edge portion14aand the edge portion14bare fitted respectively into the groove portion17aof the first standing wall surface16aand the groove portion17bof the second standing wall surface16b.

The thicknesses of the edge portions14a,14b, and the extending portions14c,14d(seeFIG. 2) in this embodiment are set substantially the same as the thicknesses of the bottom plate25band the upper plate25a. These edge portions14a,14band the extending portions14c,14dhave spring elasticity by appropriate selection of thickness and material thereof.

Although the sub air chamber member10in the above-described embodiment is made of (but is not limited to) a resin, the sub air chamber member10may be made of other materials such as metal. Incidentally, in a case of resin molding, in consideration of weight saving of the sub air chamber member10, improvement in mass-productivity, reduction in manufacturing cost, ensuring the airtightness of the sub air chamber SC, and the like, a resin that allows blow-molding and is light and highly rigid is preferable. Particularly, polypropylene, which is durable against repeated bending fatigue, is preferable.

The rim11to which the sub air chamber member10is fitted will be described below.

The rim11has the well portion11c, which is recessed toward the inner side (rotation center side) with respect to the wheel radius direction, between the bead sheet portions (not shown) of a tire, the bead sheet portions being formed at the both end portions with respect to the wheel width direction Y shown inFIG. 1.

The well portion11cis provided in order to put in the bead portions (not shown) of a tire (not shown) in attaching the tire to the rim11. Incidentally, the well portion11cin this embodiment is formed in a cylindrical shape with substantially the same diameter throughout the wheel width direction Y.

The annular standing wall15stands from the outer circumferential surface11dof this well portion11csuch as to extend along the circumferential direction of the rim11.

Returning again toFIG. 3, the standing wall15is arranged, standing from the outer circumferential surface11dsuch as to form the first standing wall surface16astanding from the outer circumferential surface11dof the well portion11cto the outer side with respect to the wheel radial direction Z (the upper side in the sheet ofFIG. 3, the same hereinafter).

The side surface portion11eformed on the inner side (left side in the sheet ofFIG. 3), with respect to the wheel width direction Y, of the well portion11cis provided with the second standing wall surface16bthat is arranged such as to substantially face the first standing wall surface16a. Incidentally, the standing wall15in this embodiment is integrally formed with the well portion11cin casting the rim11.

The first standing wall surface16aand the second standing wall surface16bare respectively provided with the groove portion17aand the groove portion17b. The groove portions17aand17bare formed along the circumferential direction of the outer circumferential surface11dof the well portion11cand form annular circumferential grooves. The edge portion14aand the edge portion14bof the sub air chamber member10are fitted in the groove portions17aand17b. Incidentally, the groove portions17aand17bin this embodiment are formed by machining the standing wall15and the side surface portion11erespectively.

The method of attaching the sub air chamber member10to the well portion11cwill be described below.FIGS. 5A and 5Bare process illustrations for illustrating a method for attaching the sub air chamber member10to the well portion11c.

Incidentally, attaching of the sub air chamber member10to the well portion11cin this embodiment assumes using a pusher (pressing device)50(seeFIGS. 5A and 5B) for pressing the edge portion14bat a position close to the groove portion17btoward the outer circumferential surface11dof the well portion11c.

As the pusher50, for example, one that presses the edge portion14b(seeFIGS. 5A and 5B) by the air pressure of an air cylinder can be adopted.

Incidentally, inFIGS. 5A and 5B, the pusher50is shown by virtual lines (alternate long and two short dashes lines) for the convenience of drawing.

Although the pusher50used in this embodiment is (but is not limited to) a plate shaped member provided with an edge portion having an arc-shaped outline with a curvature in the longitudinal direction (the wheel circumferential direction X inFIG. 2), of the sub air chamber member10, a design of the pusher50can be changed appropriately.

In this attaching method, as shown inFIG. 5A, first, the sub air chamber member10is inclined, and the edge portion14alocated in the vicinity of the rotation preventing member19is partially fitted into the groove portion17aof the first standing wall surface16a. Herein, as shown inFIG. 1, the rotation preventing member19is fitted into the cut-away portion15aof the standing wall15.

Then, inFIG. 5A, the pusher50shown by virtual lines is made contact with the edge portion14b. Symbol11drepresents the outer circumferential surface of the well portion11c.

Then, as shown inFIG. 5B, when the pusher50presses the edge portion14btoward the outer circumferential surface11dof the well portion11c, as the inclination angle of the sub air chamber member10to the outer circumferential surface11dof the well portion11cbecomes smaller, the edge portion14aon the both sides sandwiching the rotation preventing member19is gradually fitted into the groove portion17aof the first standing wall surface16a.

Herein, the edge portion14bhaving spring elasticity warps, corresponding to the magnitude of the pressing force of the pusher50.

Then, when the edge portion14bis further pressed toward the outer circumferential surface11dof the well portion11c, as shown inFIG. 3, the edge portion14aand the edge portion14bare completely fitted respectively into the groove portion17aformed on the first standing wall surface16aand the groove portion17bformed on the second standing wall surface16b. Thus, the sub air chamber member10is fitted to the well portion11c.

The actions and effects of the vehicle wheel1in this embodiment will be described below.

As shown inFIG. 3, the vehicle wheel1is engagingly fixed by that the edge portions14a,14bare fitted into the groove portions17a,17bof the first and second standing wall surfaces16a,16b.

On the sub air chamber member10fixed to the outer circumferential surface11dof the well portion11c, the action by the constrain forces caused by engaging fitting of the edge portions14a,14bto the first and second standing wall surfaces16a,16bis less significant at the end portion with respect to the wheel circumferential direction X and the extending portion14cthan in a region closer to the central portion, with respect to the wheel circumferential direction X, of the main body portion13. Accordingly, the deformation amount caused by the centrifugal force during rotation of the wheel is larger at the end portion with respect to the wheel circumferential direction X and the extending portion14cthan in a region closer to the central portion.

In a conventional sub air chamber member10, the tube body18protrudes in the wheel circumferential direction X from the position that is at the end portion, with respect to the wheel circumferential direction X, of the main body portion13and is substantially the central position with respect to the wheel width direction Y. As shown inFIG. 7, in a conventional sub air chamber member10, the darkest shaded portion10awith the largest deformation amount (lifted degree) out of the shaded portions categorized in three kinds by gray scale is largely distributed along the wheel circumferential direction X of the sub air chamber member10.

In the sub air chamber member10of such a conventional vehicle wheel, at the central portion, with respect to the wheel width direction Y, of the main body portion13, the central portion being distant from the edge portions14a,14bwhich are firmly constrained by the first and second standing wall surfaces16a,16b, disposed is the tube body18, which increases the mass factor of the centrifugal force (F=mrw2: m mass, r radius, ω angular speed). This also causes an increase in the deformation amount at the central portion with respect to the wheel width direction Y. The increase in the deformation amount significantly decreases the critical rotational speed of the wheel, the critical rotational speed detaching the sub air chamber member10from the well portion.

On the other hand, as described above, in the vehicle wheel1in this embodiment, the tube body18is arranged such as to be biased to the edge portion14afrom the center line10fwith respect to the wheel width direction Y of the main body portion13, in other words, the width direction of the outer circumferential surface11d(seeFIG. 1).

FIG. 6referred to below is a partial enlarged perspective view in the vicinity of the tube body18of the sub air chamber member10of the vehicle wheel1in the embodiment, representing the state of deformation of the sub air chamber member10due to the centrifugal force generated at the maximum assumed rotational speed of the wheel, as deformation amount distribution.

Incidentally, the deformation amount herein was obtained by a simulation testing by CAE (Computer Aided Engineering).

The shaded portion10aout of the shaded portions categorized in three kinds by gray scale represents the region with the largest deformation amount (lifted degree) from the outer circumferential surface11dof the well portion11c(seeFIG. 3) to the centrifugal direction. The shaded portion10brepresents the region with a medium deformation amount (lifted degree). The shaded portion10crepresents the region with a small deformation amount (lifted degree). The hollow portion10drepresents the region with little deformation.

As shown inFIG. 6, in the sub air chamber member10in this embodiment, the shaded portion10awith the largest deformation amount (lifted degree) is significantly reduced than in the sub air chamber member of the conventional vehicle wheel shown inFIG. 7. Further, unlike the conventional sub air chamber member of a conventional vehicle wheel1, the darkest shaded portion10aat the extending portion14cends at the vicinity of the center line10fwith respect to the wheel width direction Y, being separated from the darkest shaded portion10aat the main body portion13. Further, also in the region where the tube body18acting to increase the mass factor of centrifugal force is biased to the edge portion14a, the deformation amount (lifted degree) is small to be within the deformation amount of the shaded portion10c.

Incidentally, although not shown, in comparison with a sub air chamber member with assumption that the tube body18is not present at the end portion of the main body portion13, the deformation amount, at the center in the wheel width direction Y, of the extending portion14cshown inFIG. 6increased only by 13% (The deformation amount, to the centrifugal direction, of the portion formed by integration of the tube body18and the extending portion14cinFIG. 7increased by 33%.) The deformation amount (the displacement length at position Q in the direction perpendicular to the surface) of the bottom plate (not shown) at position Q increased only by 45% (increased by 64% inFIG. 7). The deformation amount (the displacement length at position R in the direction perpendicular to the surface) of the upper plate25aat position R increased only by 40% (increased by 70% inFIG. 7).

In the vehicle wheel1in this embodiment, the tube body18is arranged such as to be biased to the edge portion14a, which is engagingly fixed to the first standing wall surface16aand firmly constrained by the first standing wall surface16a. Thus, unlike the sub air chamber member10(seeFIG. 7) of a conventional vehicle wheel, the deformation of the sub air chamber member10of this vehicle wheel1is effectively prevented when a centrifugal force is applied to the tube body18.

Accordingly, the vehicle wheel1in this embodiment makes it possible to set the critical rotational speed of the wheel (the critical rotational speed at which the sub air chamber member10is detached from the well portion11c) higher than the critical rotational speed of a conventional wheel.

Further, in the vehicle wheel1, the protruding portion18is formed integrally with the extending portion14c. Accordingly, the vehicle wheel1makes it possible to reduce the deformation of the protruding portion18itself being supported by the extending portion14c. Thus, the vehicle wheel1realizes a stable silencing function.

Further, in the vehicle wheel1, the protruding portion18protrudes in the wheel circumferential direction X further than the end portion, with respect to the wheel circumferential direction X, of the extending portion14c. Accordingly, in the vehicle wheel1, the extending portion14cis further back than the protruding portion18toward the main body portion13, forming a step. As a result, the stiffness of the extending portion14cis increased so that the deformation of the sub air chamber member10, at the time when a centrifugal force is applied to the protruding portion18, is further effectively prevented.

Further, in the vehicle wheel1in this embodiment, as the communication hole18a(seeFIG. 3) has a cross-sectional shape longitudinal in the wheel radial direction Z (seeFIG. 3), it is possible to arrange the tube body18, the tube body18being provided with the communication hole18a, with a bias to the edge portion14a. Thus, the vehicle wheel1further more effectively prevents the deformation of the sub air chamber member10when a centrifugal force is applied to the tube body18, and it is thereby possible to set the critical rotational speed of the wheel to an even higher speed than conventionally.

Still further, as the communication hole18ahas a longitudinal tongue shape, the tip end of the tongue shape is in a curved shape. Thus, the stiffness of the protruding portion18itself including the communication hole18atherein is increased. As a result, the vehicle wheel1further more effectively prevents the deformation of the sub air chamber member10when a centrifugal force is applied to the tube body18.

Yet further, the tube body18is arranged being biased to the edge portion14awhere the rotation preventing member19is formed. Accordingly, as described above, it is possible to avoid the protruding portion18from interference with the pusher50in pressing the edge portion14bby the pusher50. Thus, for this vehicle wheel1, the sub air chamber member10can be easily attached to the rim11without disturbance by the protruding portion18in this pressing.

Further, as the sub air chamber member10is formed from a resin, this vehicle wheel1makes it possible to realize reduction in weight, improvement of mass productivity, reduction in manufacturing cost, ensuring air tightness of the sub air chamber SC, and the like of the sub air chamber member10.

Although the above embodiment has been described above, the present invention is not limited to the above embodiment and can be carried out in various ways without limitation.

Although, in the above-described embodiment, the tube body18is formed integrally with the later-described extending portion14c(seeFIG. 2), it is also possible to make the tube body18protrude from the main body portion13, separately and independently from the extending portion14c.

Further, although, in the above-described embodiment, the communication hole18ais arranged to have a cross-section in a longitudinal tongue shape, it is also possible by the invention to arrange a tube body18whose communication hole18ahas a cross-section in a shape of a longitudinal ellipse or a longitudinal polygon, and further, it is not required that the cross-sectional shape is longitudinal.

DESCRIPTION OF REFERENCE SYMBOLS

1: vehicle wheel10: sub air chamber member (Helmholtz resonator)10f: center line of main body portion11c: well portion11d: outer circumferential surface of well portion13: main body portion14a: edge portion14b: edge portion16a: first standing wall surface16b: second standing wall surface18: tube body (protruding portion)18a: communication hole25a: upper plate25b: bottom plateX: wheel circumferential directionY: wheel width directionZ: wheel radial directionSC: sub air chamberSC1: first sub air chamberSC2: second sub air chamberMC: tire air chamber