Abstract: A navigation apparatus includes a memory that stores registered routes, wherein each registered route includes a previously traveled route, a corresponding starting point, and a corresponding destination point. The navigation apparatus includes a controller that searches for a route from a specified starting point to a specified destination point, compares the searched route with the registered routes, and utilizes, if a corresponding starting point is substantially identical to the specified starting point or a corresponding destination point is substantially identical to the specified destination point, a portion of a registered route including the substantially identical starting point or the substantially identical destination point as a navigation route.

Abstract: A navigation apparatus includes a memory that stores registered routes, wherein each registered route includes a previously traveled route, a corresponding starting point, and a corresponding destination point. The navigation apparatus includes a controller that searches for a route from a specified starting point to a specified destination point, compares the searched route with the registered routes, and utilizes, if a corresponding starting point is substantially identical to the specified starting point or a corresponding destination point is substantially identical to the specified destination point, a portion of a registered route including the substantially identical starting point or the substantially identical destination point as a navigation route.

Abstract: A roller retainer 11 encloses an outer periphery of the roller 9 situated on a diagonal 20 when the roller 9 is viewed from the side surface thereof. Whether the rollers 9 are arranged in a parallel manner or in a cross manner, the roller retainer 11 is able to keep a constant position and thus the disposition of the roller retainer 11 is free from the influence of the direction the roller 9. Also, since the roller retainer 11 restricts a corner portion 9a of the roller 9, the roller 9 is difficult to slip off the roller retainer 11 and thus the roller 9 can be restricted positively, thereby being able to control the skew of the roller 9.

Abstract: In a roller screw, a plurality of rollers 16 interposed between a nut member 14 and a screw shaft 12 are composed of a forward-motion load roller group 17, the rollers 16 of which are arranged in such a manner that the center lines thereof are set at a given angle &agr; with respect to the center line of the screw shaft 12, and backward-motion load roller group 18, the rollers 16 of which are arranged in such a manner that the center lines thereof are set at an angle &bgr;, which is different from the angle &agr;, with respect to the center line of the screw shaft 12; and, the forward-motion load roller group 17 and backward-motion load roller group 18 are disposed such that they are separated from each other.

Abstract: A roller retainer 11 encloses an outer periphery of the roller 9 situated on a diagonal 20 when the roller 9 is viewed from the side surface thereof. Whether the rollers 9 are arranged in a parallel manner or in a cross manner, the roller retainer 11 is able to keep a constant position and thus the disposition of the roller retainer 11 is free from the influence of the direction the roller 9. Also, since the roller retainer 11 restricts a corner portion 9a of the roller 9, the roller 9 is difficult to slip off the roller retainer 11 and thus the roller 9 can be restricted positively, thereby being able to control the skew of the roller 9.

Abstract: In a roller screw, a plurality of rollers 16 interposed between a nut member 14 and a screw shaft 12 are composed of a forward-motion load roller group 17, the rollers 16 of which are arranged in such a manner that the center lines thereof are set at a given angle &agr; with respect to the center line of the screw shaft 12, and a backward-motion load roller group 18, the rollers 16 of which are arranged in such a manner that the center lines thereof are set at an angle &bgr;, which is different from the angle &agr;, with respect to the center line of the screw shaft 12; and, the forward-motion load roller group 17 and backward-motion load roller group 18 are disposed such that they are separated from each other.