Swingable vehicle

In a three-wheel vehicle in which left and right suspension arms are attached to a rear portion of a vehicle body frame so as to be capable of swinging in a vertical direction, and driving wheels connected via a drive shaft are rotatably mounted to distal ends of the suspension arms comprising:

• a vehicle frame structure including an under frame constituting a lower portion of the vehicle body frame with a rising portion inclining upwardly towards a rear in front of the drive shaft;
• a fore-and-aft extending portion extending substantially in a fore-and-aft direction above the drive shaft;
• and a downwardly extending portion extending downwardly behind the drive shaft;
• wherein said suspension arms are formed into an A-shape and are supported by a lower part of the rising portion and a lower end of the downwardly extending portion via a supporting shaft, and
• wherein the rising portion, the fore-and-aft extending portion, and the downwardly extending portion are formed into a single frame, and the left and right suspension arms are supported via a single supporting shaft.

A three-wheel swingable vehicle comprising:

• wheels driven through drive shafts;
• a pair of constant velocity joints operatively connected to each of said drive shafts;
• a ball spline mechanism provided between said constant velocity joints for enabling the distance between said constant velocity joints to be contracted and extended;
• and
• said ball spline mechanism includes a spline shaft having an outer circumferential surface provided with a plurality of shaft-side spline grooves extending in the axial direction, an outer tube surrounding the periphery of said spline shaft and having an inner circumferential surface provided with a plurality of tube-side spline grooves extending in the axial direction and a plurality of balls capable of rolling while being fitted in said shaft-side spline grooves and said tube-side spline grooves,
• wherein said drive shafts are mounted to a swingable three-wheel vehicle in which a vehicle body frame is swung in a left-right direction relative to a double wishbone type suspension for supporting rear wheels as said wheels,
• the vehicle further comprising:
• left and right suspension arms mounted to a vehicle body frame, said vehicle body frame being swingable in the left-right direction relative to said suspension arms;
• wherein said suspension arms are provided at left and right positions and at upper and lower positions to constitute a double wishbone type suspension, left and right drive wheels are supported by said double wishbone type suspension and said drive wheels are connected to a drive source side through drive shafts extending in a front-rear direction.