1. Field of the Invention
The invention relates to a wheel rim, more particularly to a wheel rim having annular side walls with hollow segments.
2. Description of the Related Art
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Therefore, the object of the present invention is to provide a wheel rim that has a strong and light construction, and that can effectively dissipate heat generated during a wheel braking action.
Accordingly, a wheel rim of the present invention comprises an annular rim body having a horizontally disposed rim axis. The rim body includes an annular base wall, and a pair of opposite annular side walls. The annular base wall is formed with a plurality of spoke fastening holes spaced apart from each other, and has two opposite lateral edges. The annular side walls extend radially, outwardly and respectively from the lateral edges of the annular base wall. Each of the annular side walls includes a hollow segment that defines an annular hole. The hollow segment has an inner wall portion disposed at an inner side of the annular hole and facing the other one of the annular side walls, and an outer wall portion connected to the inner wall portion and disposed at an outer side of the annular hole opposite to the inner side of the annular hole.
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.
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The annular base wall 4 is formed with a plurality of spoke fastening holes 41 spaced apart from each other, and has two opposite lateral edges 42.
The annular side walls 6 extend radially, outwardly and respectively from the lateral edges 42 of the annular base wall 4. Each of the annular side walls 6 includes a hollow segment 62 that defines an annular hole 65. The hollow segment 62 has an inner wall portion 63 disposed at an inner side of the annular hole 65 and facing the other one of the annular side walls 6, and an outer wall portion. 64 connected to the inner wall portion 63 and disposed at an outer side of the annular hole 65 opposite to the inner side of the annular hole 65. Each of the annular side walls 6 further includes an interior wall surface 66 that faces and defines the annular hole 65 in the hollow segment 62 thereof, and that has an elongated radial cross-section relative to the rim axis (L).
The annular connecting wall 5 interconnects the annular side walls 6, surrounds the annular base wall 4, and cooperates with the annular side walls 6 to define an annular tire retaining groove 50.
The inner wall portion 63 of the hollow segment 62 of each of the annular side walls 6 includes a first surface 631 facing the annular tire retaining groove 50, and a second surface 632 opposite to the first surface 631 and facing the annular hole 65. Each of the annular side walls 6 further includes a connecting segment 61 interconnecting the hollow segment 62 thereof and the annular base wall 4. In this embodiment, the inner wall portion 63 of each of the hollow segments 62 of the annular side walls 6 extends radially and outwardly from the connecting segment 61 of a respective one of the annular side walls 6, and is connected to the annular connecting wall 5. The outer wall portion 64 of each of the hollow segments 62 of the annular side walls 6 includes an oblique part 641 that extends obliquely and outwardly from the connecting segment 61 of the corresponding one of the annular side walls 6, a radially extending part 642 that extends from the oblique part 641 in radial outward directions relative to the rim axis (L) and that has a radial outer edge 6421 distal from the annular base wall 4, and a connecting end part 643 that extends from the radial outer edge 6421 of the radially extending part 642 to connect to the inner wall portion 63. In this embodiment, the connecting end part 643 of the outer wall portion 64 of each of the hollow segments 62 is formed with a plurality of elongated vent holes 640 spaced apart from each other and in spatial communication with the annular hole 65. Preferably, the vent holes 640 in the connecting end parts 643 of the two hollow segments 62 are staggered relative to each other. The radially extending part 642 of the outer wall portion 64 of each of the hollow segments 62 further includes a third surface 644 facing the annular hole 65, and a brake pad contacting surface 645 opposite to the third surface 644 and disposed outside the annular hole 65. The second surface 632 of the inner wall portion 633 of a respective one of the annular side walls 6 and the third surface 644 of the outer wall portion 64 of the same annular side wall 6 form the corresponding interior wall surface 66.
The interior wall surface 66 of each of the annular side walls 6 has a radial outer end 661 distal from the annular base wall 4 and a radial inner end 662 opposite to the radial outer end 661. The radial outer ends 661 of the interior wall surfaces 66 of the annular side walls 6 are disposed on a first imaginary cylindrical plane (H1). The radial inner ends 662 of the interior wall surfaces 66 of the annular side walls 6 are disposed on a second imaginary cylindrical plane (H2). The annular connecting wall 5 has a radial outer surface 51 that faces the annular tire retaining groove 50, and that has a pair of connecting edges 52 connected respectively to the annular side walls 6 between the first and second imaginary cylindrical planes (H1), (H2).
The interior wall surface 66 of the hollow segment 62 of each of the annular side walls 6 can distribute lateral stresses, such that the lateral stresses will not be directly applied to the inner wall portion 63 and concentrated at the connecting edge 52, thereby avoiding the occurrence of cracks.
The hollow segments 62 of the annular side walls 6 can also minimize degradation of the inserted tire and other components of the rim body 20 due to heat that is generated from the friction between the brake pads 8 and the brake pad contacting surface 645 of the outer wall portion 64 of each of the annular side walls 6 during a wheel braking action. In particular, since the vent holes 640 in the outer wall portion 64 of each of the annular side walls 6 are in spatial communication with the annular holes 65 in the hollow segments 62, when the wheel rim is rotating, the air inside the hollow segments 62 will be induced to flow out quickly, thereby resulting in air circulation to dissipate heat. In this embodiment, the vent holes 640 are formed in the connecting end part 643 of the outer wall portion 64 of each of the annular side walls 6 in centrifugal directions relative to the rim axis (L) for strengthening the air circulation.
Preferably, the total thickness of the inner wall portion 63 of each of the annular side walls 6 and the connected one of the outer wall portions 64, i.e., the sum of the distance (W1) (See
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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.