Wheel for vehicle

Abstract

A wheel for vehicle 1 is provided with a disc 10 and a rim 20 and has a braking device 30 housed therein. An annular flange portion 41 protruded inward from a bead seat portion 22 in a radial direction of the wheel 1 is disposed at an end of the rim 20 on a side opposite to the disc 10. The flange portion 41 has an inclined surface 41a on a side opposite to the disc 10. The flange portion 41 is inclined toward the disc 10 in a direction toward a central axis L of the wheel 1. The inclined surface 41a acts to reduce air resistance at the wheel 1 while the vehicle is running and guides a portion of an underfloor airflow to an inner space of the wheel 1 to secure an amount of air for cooling the braking device 30.

Claims

1. A wheel for vehicle comprising: a disc; a rim; a braking device housed therein; an annular flow straightener disposed at an end of the rim on a side opposite to the disc; and the flow straightener having an annular protruded portion protruded inward from a bead seat portion of the rim in a radial direction of the wheel, wherein the protruded portion has an annular inclined surface on a side opposite to the disc, the inclined surface inclined toward the disc in a direction toward a central axis of the wheel; the inclined surface of the protruded portion is provided as a first inclined surface; the protruded portion further has a second inclined surface having an annular configuration and oriented toward the disc; the second inclined surface is inclined away from the disc in the direction toward the central axis of the wheel; and an annular top portion is formed where the first inclined surface and the second inclined surface intersect with each other.

2. The wheel for vehicle according claim 1, wherein the flow straightener is integrally formed with the rim.

3. The wheel for vehicle according to claim 1, wherein: the flow straightener is a separate component from the rim; and the flow straightener is attached to the rim.

4. A wheel for vehicle comprising: a disc; a rim; a braking device housed therein; an annular flow straightener disposed at an end of the rim on a side opposite to the disc; and the flow straightener having an annular protruded portion protruded inward from a bead seat portion of the rim in a radial direction of the wheel, wherein the protruded portion has an annular inclined surface on a side opposite to the disc, the inclined surface inclined toward the disc in a direction toward a central axis of the wheel; the flow straightener has an annular wall portion extending along a rim flange portion of the rim; a side surface of the wall portion on a side opposite to the disc is a flat surface orthogonal to the central axis of the wheel; the side surface continues to the inclined surface; the inclined surface of the protruded portion is provided as a first inclined surface; the protruded portion further has a second inclined surface having an annular configuration and oriented toward the disc; the second inclined surface is inclined away from the disc in the direction toward the central axis of the wheel; and an annular top portion is formed where the first inclined surface and the second inclined surface intersect with each other.

5. A wheel for vehicle comprising: a disc; a rim; a braking device housed therein, an annular flow straightener disposed at an end of the rim on a side opposite to the disc; and the flow straightener having an annular protruded portion protruded inward from a bead seat portion of the rim in a radial direction of the wheel, wherein the protruded portion has an annular inclined surface on a side opposite to the disc, the inclined surface inclined toward the disc in a direction toward a central axis of the wheel; the inclined surface is inclined 5 to 15 degrees with respect to a plane orthogonal to the central axis of the wheel; the inclined surface of the protruded portion is provided as a first inclined surface; the protruded portion further has a second inclined surface having an annular configuration and oriented toward the disc; the second inclined surface is inclined away from the disc in the direction toward the central axis of the wheel; and an annular top portion is formed where the first inclined surface and the second inclined surface intersect with each other.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a plane cross-sectional view of a wheel for vehicle according to a first embodiment of the present invention.

(2) FIG. 2 is an enlarged cross-sectional view of a flow straightener that is an important portion of the wheel for vehicle.

(3) FIG. 3 is an enlarged cross-sectional view of a flow straightener of a wheel for vehicle according to a second embodiment of the present invention.

(4) FIG. 4 is a plane cross-sectional view of a wheel for vehicle according to a third embodiment of the present invention.

(5) FIG. 5 is an enlarged cross-sectional view of a flow straightener of a wheel for vehicle according to a fourth embodiment of the present invention.

(6) FIG. 6 is an enlarged cross-sectional view of a flow straightener of a wheel for vehicle according to a fifth embodiment of the present invention.

(7) FIG. 7 is an enlarged cross-sectional view of a flow straightener of a wheel for vehicle according to a sixth embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(8) A wheel for vehicle according to a first embodiment of the present invention will be described hereinafter with reference to FIGS. 1 and 2.

(9) A wheel for vehicle 1 shown in FIG. 1 is made of a cast aluminum alloy (light metal), for example. The wheel for vehicle 1 integrally includes a disc 10 having a generally circular disc configuration and a rim 20 having a generally circular cylindrical configuration that continues from a peripheral edge of the disc 10. A tire T is mounted on an outer periphery of the rim 20.

(10) The disc 10 has a hub attachment portion 11 having a circular disc configuration in a central portion thereof, a peripheral edge portion 12 having an annular configuration and spoke portions 14 extending radially for connecting the hub attachment portion 11 and the peripheral edge portion 12.

(11) A hub hole 11a and a plurality of bolt holes 11b are formed in the hub attachment portion 11. Openings 15 are formed between the spoke portions 14.

(12) As with a standard rim of a wheel, the rim 20 includes a rim drop portion 21, a pair of bead seat portions 22 that continues from opposite ends of the rim drop portion 21 and a pair of rim flange portions 23.

(13) The disc 10 is disposed at an end of the rim 20 located outside (side opposite to a vehicle body) in an axial direction of the wheel. An inner space 2 of the wheel 1 is formed by the disc 10 and the rim 20. An opening 3 is formed in an inside of the rim 20 (vehicle body side) in the axial direction of the wheel.

(14) A hub (not shown) of a vehicle extends into the inner space 2 through the opening 3. The hub attachment portion 11 of the disc 10 is fixed to the hub. A braking device 30 is received in the inner space 2.

(15) The braking device 30 includes a brake rotor 31 fixed to the hub (not shown) and a brake caliper 32. The brake caliper 32 has a pair of brake pads (not shown) moved by hydraulic cylinder. Braking by friction can be realized by pressing the brake pads against the brake rotor 31.

(16) The openings 15 not only improve design but also let out heat generated by the braking device 30.

(17) Special features of the present invention will be described below. As shown in FIGS. 1 and 2, an annular flow straightener 40 is provided at an end of the rim 20 on the vehicle body side (side opposite to the disc 10). The flow straightener 40 is formed integrally with the rim 20. The flow straightener 40 has an annular flange portion 41 (protruded portion having a configuration of a flange) and an annular wall portion 42. The flange portion 41 is protruded inward from the bead seat portion 22 in a radial direction of the wheel 1. The wall portion 42 extends along the rim flange portion 23 and is formed integrally with the rim flange portion 23.

(18) A side surface of the flange portion 41 on the vehicle body side is an inclined surface 41a (tapered surface, conical surface) inclined toward the disc 10 in a direction toward a central axis L. A side surface of the wall portion 42 on the vehicle body side is an annular flat surface 42a orthogonal to the central axis L of the wheel 1. The flat surface 42a is continuous from the inclined surface 41a.

(19) A width a of the flow straightener 40 in the radial direction of the wheel and an angle b of the inclined surface 41a are determined so as to restrain the partial separation of an underfloor airflow (airflow entering through the opening 3) and at the same time to secure an amount of airflow required for cooling the braking device 30 inside the wheel 1. Preferably, the width a is from 50 mm to 80 mm. Preferably, the angle b of the inclined surface 41a is from 5 degrees to 15 degrees. If the angle b is less than 5 degrees, it is difficult to secure the amount of airflow for cooling the braking device 30. If the angle b is greater than 15 degrees, air resistance is increased and an effect of the flow straightener 40 is reduced although the amount of airflow for cooling may be secured.

(20) In this embodiment, the wheel 1 and the flow straightener 40 are integrally formed. Specifically, after the wheel 1 is casted, the flow straightener 40 is formed by flow forming and machine processing.

(21) Action of the wheel 1 is described below.

(22) As indicated by arrow A in FIG. 1, the underfloor airflow is straightened by the flat surface 42a of the wall portion 42 and the inclined surface 41a of the flange portion 41 that continues from the flat surface 42a in a front portion of the wheel 1 while the vehicle is running. Therefore, the separation of the airflow is restricted, and generation of vortex is restricted. Thereby, the air resistance is reduced. Moreover, since the underfloor airflow A is straightened to flow backward, the underfloor airflow A is restricted from hitting an inner wall surface of the rim 20 in the rear portion of the wheel 1. Thereby, air resistance caused by the hitting of the inner wall surface by the underfloor airflow A is also reduced.

(23) A portion of the underfloor airflow A is guided to the inside of the wheel 1 by the inclined surface 41a and cools the braking device 30. Then the underfloor airflow A flows out of the wheel 1 through the openings 15 of the disc 10 and joins a side airflow B that flows outside of the wheel 1.

(24) The flow straightener 40 is disposed on the vehicle body side of the rim 20, and therefore, the flow straightener 40 is less visible from outside. Modification such as reducing opening areas of the openings 15 of the disc 10 is not required to reduce the air resistance. Therefore, the design of the wheel is not compromised.

(25) Other embodiments of the present invention will be described hereinafter with reference to the drawings. In the description of these embodiments, same reference numerals will be used to indicate features corresponding to those of foregoing embodiments, and explanation thereof will be omitted.

(26) In a second embodiment shown in FIG. 3, a flow straightener 40A is made of an annular member 49 that is a separate component from a rim 20. The annular member 49 includes a flange portion 41 having an inclined surface 41a, a wall portion 42 having a flat surface 42a and a plurality of attachment portions 43 protruded outward from near a boundary of the flange portion 41 and the wall portion 42 in an axial direction of a wheel. The plurality of attachment portions 43 are formed spaced from each other in a circumferential direction. A protrusion 43a is formed outside of a distal end portion of the attachment portion 43 in a radial direction of the wheel. When the annular member 49 is pressed into the rim 20, the attachment portions 43 are elastically deformed and the protrusions 43a ride over a bead seat portion 22. When the annular member 49 is pressed further into the rim 20, the protrusions 43a are fitted into annular notches 24 formed in an inner peripheral surface of the rim 20 adjacent to the bead seat portion 22, and the attachment portions 43 are elastically returned.

(27) In a state where the annular member 49 is attached, the flange portion 41 is protruded inward from the bead seat portion 22 in the radial direction of the wheel. The wall portion 42 is contacted with a side surface of a rim flange portion 23 on the vehicle body side and the flat surface 42a of the wall portion 42 is flush with a side surface 23a of an outer peripheral edge of the rim flange portion 23 on the vehicle body side.

(28) Since an action of the flow straightener 40A while the vehicle is running is similar to that of the flow straightener in the first embodiment, a description thereof will be omitted.

(29) In a third embodiment shown in FIG. 4, an annular flow straightener 50 is formed at an end of a rim 20 on the vehicle body side. The flow straightener 50 includes an annular protruded portion 51 and a wall portion 52. The protruded portion 51 has a triangular cross-sectional configuration and is protruded inward from a bead seat portion 22 in a radial direction of a wheel 1. The wall portion 52 is disposed on the vehicle body side of a rim flange portion 23 and is formed integrally with the rim flange portion 23.

(30) As shown in FIG. 4, the protruded portion 51 has an annular first inclined surface 51a (tapered surface, conical surface) farther from the disc 10 and an annular second inclined surface 51b (tapered surface, conical surface) closer to the disc 10. As with the inclined surface 41a in the first and second embodiments, the first inclined surface 51a is inclined toward the disc 10 in a direction toward a central axis L of the wheel 1. The second inclined surface 51b is inclined away from the disc 10 in a direction toward the central axis L of the wheel 1.

(31) Cross-sectional outlines of the first inclined surface 51a and the second inclined surface 51b may be straight or curved.

(32) An annular top portion 51c is formed where the first inclined surface 51a and the second inclined surface 51b intersect with each other. A cross-sectional outline of the top portion 51c may be pointed. However, it is preferable that the cross-sectional outline of the top portion 51c is a convex curve having a relatively small radius of curvature.

(33) A flat surface 52a orthogonal to the central axis of the wheel is provided on the vehicle body side of the wall portion 52. The flat surface 52a is continuous from the inclined surface 51a.

(34) As with the first and second embodiments, as indicated by arrow A in FIG. 4, an underfloor airflow is straightened by the flat surface 52a and the inclined surface 51a in a front portion of the wheel 1 and a portion of the underfloor airflow is guided by the inclined surface 51a to cool a braking device 30.

(35) In the third embodiment, the following effects can also be achieved. In a rear portion of the wheel 1, when the underfloor airflow A hits an inner wall surface of the rim 20, the underfloor airflow A is divided at the top portion 51c of the protruded portion 51 into a flow along the inclined surface 51a and a flow along the inclined surface 51b. The airflow flowing along the inclined surface 51a is straightened by the flat surface 52a and flows rearward. The airflow flowing along the inclined surface 51b is guided by an inside of the wheel 1 and cools the braking device 30. Then the airflow flows out of the wheel 1 through openings 15 of the disc 10 and joins a side airflow flowing outside of the wheel 1.

(36) Since the portion of the underfloor airflow is divided and smoothly flows along the inclined surfaces 51a, 51b as mentioned above, air resistance can be reduced.

(37) As with the first and second embodiments, an inclination angle of the inclined surface 51a is preferably from 5 degrees to 15 degrees in the third embodiment. However, a larger inclination angle is acceptable because a portion of increase in the air resistance due to the increase in the inclination angle is cancelled out by the reduction in the air resistance due to the division of the flow mentioned above.

(38) In a fourth embodiment shown in FIG. 5, a cross-sectional outline of a first inclined surface 51a is convexly curved and smoothly continues to an inclined side surface 23a of a rim flange portion 23 on a vehicle body side.

(39) In a fifth embodiment shown in FIG. 6, a protruded portion 51 of a flow straightener 50A is composed of an annular member 55 and a cap 56 that are separate components from a rim 20. The annular member 55 having a generally mountain-shaped cross section includes an annular groove 55a and screw insertion holes 55b formed in a bottom surface of the groove 55a spaced from each other in a circumferential direction. The annular member 55 is fixed to a bead seat portion 22 of the rim 20 by screwing screws 57 inserted through the screw insertion holes 55b into screw holes 22a formed in an inner peripheral surface of the bead seat portion 22.

(40) The cap 56 has a halved annular configuration having a bent cross-section. The groove 55a is closed by fixing the cap 56 to a top portion of the annular member 55.

(41) A first inclined surface 51a and a second inclined surface 51b are formed in the annular member 55 and the cap 56. A top portion 51c is formed in the cap 56. The first inclined surface 51a is continuous from a side surface 23a of a rim flange portion 23 on a vehicle body side.

(42) In place of the groove 55a, countersunk holes having a diameter larger than that of a bolt head may be provided at a position of a bolt hole. In this case, a cap 56 is provided for each countersunk hole.

(43) In a sixth embodiment shown in FIG. 7, a protruded portion 51 of a flow straightener 50B is an annular member 58 that is a separate component from a rim 20. The annular member 58 has first and second inclined surfaces 51a, 51b and a top portion 51c. A shallow recess 58a having an annular configuration is formed in an outer peripheral surface of the annular member 58. The annular member 58 is fixed to an inner peripheral surface of the bead seat portion 22 by adhesive 59 filled in the recess 58a.

(44) The recess 58a may be continuously or intermittently formed in a circumferential direction.

(45) The present invention is not limited to the embodiments described above, and various modifications can be adopted without departing from the scope and the spirit of the invention.

(46) The flow straightener has a wall portion having a flat surface in the first and second embodiments. Alternatively, the flow straightener may not have a wall portion. In this case, the inclined surface of the flange portion continues to the side surface of the rim flange portion.

INDUSTRIAL APPLICABILITY

(47) The present invention may be applied to a wheel for vehicle in which reduction of air resistance and cooling of a braking device are required.