1. Field of the Invention
The invention relates to a wheel rim, more particularly to a wheel rim adapted for use in bicycles.
2. Description of the Related Art
As shown in
In use, when the tire 22 contacts the ground, the tire coupling segment 122 of each of the annular side walls 12 is subjected to a lateral force (F1), and the other portions of the rim body are applied with stresses (as indicated by the arrows in
Although the structural strength of the abovementioned conventional wheel rim 1 can be strengthened by including an annular connecting wall that surrounds the annular base wall 11 and that interconnects the annular side walls 12 so as to provide pulling forces to the annular side walls 12 against the lateral forces (F1), such improvement is unable to provide sufficient structural strength against the total torque (T). Moreover, the inclusion of the annular connecting wall results in a relatively complicated wheel rim structure and a relatively high manufacturing cost.
Therefore, the object of the present invention is to provide a wheel rim having a higher structural strength.
Accordingly, a wheel rim of the present invention is adapted for retaining a tire that includes a pair of tire beads. The wheel rim comprises an annular rim body having a horizontally disposed rim axis. The rim body includes an annular base wall surrounding the rim axis and having opposite lateral edges, and a pair of annular side walls extending in radial outward directions respectively from the lateral edges of the annular base wall. Each of the annular side walls includes a hollow reinforcing segment that has a connecting edge connected to a respective one of the lateral edges of the annular base wall, and a distal edge radially spaced apart from the connecting edge, and a tire coupling segment that extends radially and outwardly from the distal edge of the reinforcing segment. The annular base wall and the reinforcing segments of the annular side walls cooperatively define an internal space. The tire coupling segments of the annular side walls cooperatively define a tire retaining space adapted for retaining the tire beads of the tire. The reinforcing segment of each of the annular side walls has an inner wall portion that confronts the internal space, an outer wall portion that is disposed at a radially outer side of the inner wall portion and that cooperates with the inner wall portion to define an annular chamber, and at least one connecting wall portion that is disposed in the annular chamber, that interconnects the inner and outer wall portions, and that cooperates with the inner and outer wall portions to form at least one H-shaped wall structure and to configure the annular chamber into at least two annular holes.
Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which:
Before the present invention is described in greater detail, it should be noted that like elements are denoted by the same reference numerals throughout the disclosure.
As shown in
The annular base wall 4 surrounds the rim axis (L) and has opposite lateral edges 42. In this embodiment, the annular base wall 4 further has a plurality of angularly spaced-apart spoke engaging holes 41 (only one is shown) adapted to be engaged with the rim engaging portions 32 of the spokes 3, respectively.
The annular side walls 5 extend in radial outward directions respectively from the lateral edges 42 of the annular base wall 4. Each of the annular side walls 5 includes a hollow reinforcing segment 51 that has a connecting edge 510 connected to a respective one of the lateral edges 42 of the annular base wall 4, and a distal edge 519 radially spaced apart from the connecting edge 510. Each of the annular side walls 5 further includes a tire coupling segment 52 extending radially and outwardly from the distal edge 519 of the reinforcing segment 51. The annular base wall 4 and the reinforcing segments 51 of the annular side walls 5 cooperatively define an internal space 501. The tire coupling segments 52 of the annular side walls 5 cooperatively define a tire retaining space 502 adapted for retaining the tire beads of the tire 33. In this embodiment, the reinforcing segment 51 of each of the annular side walls 5 has an inner wall portion 511 that confronts the internal space 501 and that has a thickness (d1), an outer wall portion 512 that is disposed at a radially outer side of the inner wall portion 511, that has a thickness (d2), and that cooperates with the inner wall portion 511 to define an annular chamber 518, and a pair of spaced-apart connecting wall portions 513 that are disposed in the annular chamber 518, that interconnect the inner and outer wall portions 511, 512, and that cooperate with the inner and outer wall portions 511, 512 to form a pair of H-shaped wall structures 517 and to configure the annular chamber 518 into three annular holes 514. Each of the annular holes 514 has a polygonal shape. The inner wall portion 511 of the reinforcing segment 51 of each of the annular side walls 5 has a connecting part 515 connected to the respective one of the lateral edges 42 of the annular base wall 4 and having a radial outer edge 5150 opposite to the annular base wall 4 and an inner surface 5151 confronting the internal space 501, and an oblique part 516 extending obliquely from the radial outer edge 5150 of the connecting part 515 to the outer wall portion 512 and having an inner surface 5161 confronting the internal space 501. The outer wall portion 512 of the reinforcing segment 51 of each of the annular side walls 5 further has an outer surface 5121 facing away from the annular chamber 518. In this embodiment, a distance between the inner surface 5151 of the connecting part 515 of the inner wall portion 511 and the outer surface 5121 of the outer wall portion 512 of a same one of the reinforcing segments 51 gradually increases in a direction away from the annular base wall 4, and a distance between the inner surface 5161 of the oblique part 516 of the inner wall portion 511 and the outer surface 5161 of the outer wall portion 512 of a same one of the reinforcing segments 51 gradually increases in a direction toward the annular base wall 4, such that sizes of the annular holes 514 in a same one of the reinforcing segments 51 decrease from the farthest one to the nearest one of the annular holes 514 relative to the annular base wall 4, i.e., the farthest one of the annular holes 514 relative to the annular base wall 4 has the largest cross-section. Each of the connecting rods 34 is inserted in the largest one of the annular holes 514 in the reinforcing segment 51 of a respective one of the annular side walls 5 for retaining an annular shape of the rim body 20. For each of the annular side walls 5, the H-shaped wall structures 517 of the reinforcing segment 51 are connected integrally to each other along an imaginary central line (K) that extends through the annular holes 514, and cross-sections of the H-shaped wall structures 517 decrease in a direction from the distal edge 519 to the connecting edge 510 of the reinforcing segment 51. For each of the annular side walls 5, each of the connecting wall portions 513 of the reinforcing segment 51 is generally perpendicular to the inner wall portion 511.
The tire coupling segment 52 of each of the annular side walls 5 has an abutment portion 521 connected to the distal edge 519 of the reinforcing segment 51 and having a thickness (W), and a tire bead coupling portion 522 projecting from the abutment portion 521 toward the tire coupling segment 52 of the other one of the annular side walls 5. In this embodiment, for each of the annular side walls 5, the sum of the thicknesses (d1, d2) of the inner and outer wall portions 511, 512 of the reinforcing segment 51 is generally equal to the thickness (W) of the abutment portion 521 of the tire coupling segment 52.
In use, the H-shaped wall structures 517 of the reinforcing segments 51 of the annular side walls 5 are capable of providing sufficient structural strength against the total torques applied on the annular side walls 5. Moreover, for each reinforcing segment 51, since the distance between the inner surface 5151 of the connecting part 515 of the inner wall portion 511 and the outer surface 5121 of the outer wall portion 512 gradually increases in a direction away from the annular base wall 4, and since the distance between the inner surface 5161 of the oblique part 516 of the inner wall portion 511 and the outer surface 5161 of the outer wall portion 512 gradually increases in a direction toward the annular base wall 4, stresses applied to the reinforcing segment 51 can be dispersed rather than being concentrated at the connecting edge 510 of the reinforcing segment 51, thereby effectively preventing fracture of the respective annular side wall 5. Furthermore, for each of the annular side walls 5, since the sum of the thicknesses (d1, d2) of the inner and outer wall portions 511, 512 of the reinforcing segment 51 is generally equal to the thickness (W) of the abutment portion 521 of the tire coupling segment 52, the strength-enhanced annular side walls 5 can be made without necessitating extra material for the rim body 20 which leads to a heavier weight.
It should be noted that, while the reinforcing segment 51 of each of the annular side walls 5 is exemplified to include two connecting wall portions 513, only one connecting wall portion 513 may be employed in other embodiments of this invention.
As shown in
While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.