1. Field of the Invention
The present invention relates to an all-terrain straddle type vehicle, and more specifically to an all-terrain straddle type vehicle having a disc brake provided within a wheel.
2. Description of the Related Art
Conventional straddle type vehicles involve a problem in that when a vehicle runs on rough terrain, mud or the like adheres onto the vehicle wheels, and the mud or the like clogs and solidifies within the wheel of each vehicle wheel. In the case of a straddle type vehicle having a disc brake provided within the wheel, in particular, mud or the like can easily clog the gap between a brake caliper and the wheel. If the running of the vehicle is continued while leaving the mud or the like clogged in the gap as it is, the clogged mud or the like is gradually compressed by the brake caliper. The mud or the like compressed in the gap between the brake caliper and the wheel is difficult to remove manually. Further, if, as a result of interference with the brake caliper, the compressed mud is scattered and thrown in the form of dust and enters the gap between a disc rotor and a brake pad, this accelerates wear of the brake pad, causing a reduction in the life of the brake pad.
Accordingly, it is necessary to quickly remove mud or the like deposited inside the wheel. A device for removing mud or the like deposited inside the wheel is disclosed in, for example, JP-A-2006-71042 (Patent Document 1).
Patent Document 1 discloses a brake caliper supporting structure in which the brake caliper includes a pair of brake pads for clamping a brake disc, a piston for pressing the brake pads, a caliper body accommodating the piston in a movable manner, and a caliper bracket mounted to a caliper supporting portion which is connected to a knuckle to support the caliper body in a movable manner, and in which the distance from the center of the vehicle wheel to the caliper supporting portion is larger than the distance between the center of the vehicle wheel to the piston. Since the caliper supporting portion is located radially outside, mud, snow, or the like adhering onto the inner side of the wheel can be scraped off by the caliper supporting portion.
However, in the case of the brake caliper disclosed in Patent Document 1, since the mud, snow, or the like inside the wheel is scraped off in the vertically downward direction by the caliper supporting portion, the majority of the mud, snow, or the like thus scraped off keeps accumulating inside the wheel. In this regard, in the case of a straddle type vehicle that runs on rough terrain, in particular, in order to improve the riding comfort by absorbing vibrations resulting from the unevenness of the road surface, it is required to provide a large suspension stroke by setting a high minimum ground clearance for the vehicle. Since an increase in suspension stroke results in a corresponding increase in the depth of the wheel, this makes mud, snow, or the like even more likely to accumulate inside the wheel. If the mud, snow, or the like that has once been scraped off is allowed to keep accumulating inside the wheel thereafter, the amount of mud, snow, or the like deposited inside the wheel increases as the running time of the vehicle becomes longer. Eventually, the removal of the old mud, snow, or the like can no longer keep pace with the rate of depositing new mud, snow, or the like, thereby resulting in clogging.