Honda Giken Kogyo Kabushiki Kaisha

Toshio Matsuno

Yoshiyuki Horii

To make a vehicle body frame welded with a rear cushion bracket as thin as possible and as light as possible. A vehicle body frame includes a bracket attached to a rear face of an upper portion of a center pipe. The bracket is attached with a rear wheel suspension and a cushion unit is supported thereon at an upper end portion thereof. The wall of the center pipe includes thick wall portions provided only at corner portions of left and right sides of a rear face wall thereof. Left and right end portions of a base portion of the bracket are welded at outer sides thereof to the thick portions of the center pipe. The wall thickness T,and T,of thick wall portions of the center pipe are made substantially equal to the wall thickness T,and T,of left and right end portions of the base portion of the bracket to be welded. Furthermore, the wall thickness of other portions of the center pipe is made thinner. The center pipe is formed by extrusion of an aluminum alloy or the like.

Attaching structure of rear cushion bracket

A pivot frame is formed as a casting of an aluminum alloy in a substantially U-shaped manner to be open toward a front side. Attaching bosses of a crankcase are placed between a left sidewall and a right sidewall of the pivot frame. Bearing portions of a rear swing arm are coaxially arranged on outer sides of the pivot frame. A pivot bolt is penetrated from one side and is fastened by a nut on the other side. An adjustment collar is interposed between the attaching boss and the right sidewall of the pivot frame. A side of a fixed portion of the adjustment collar is fixed to the right sidewall, and a side of a movable portion of the adjustment collar is pivoted by a tool. The adjustment collar allows the fastening torque of the nut to be constant, thereby preventing deformation from occurring in a fastening operation even when a pivot plate of an aluminum alloy is used.

Structure of pivot portion of rear swing arm

A vehicle body frame is formed by a head portion, a main pipe, a center pipe, a pivot frame, lower pipes and a down pipe. The head portion is a casting integrally formed with a head pipe. An oil tank is formed by a main body portion of the head portion, the down pipe, and a joint piece which is connected at a lower end thereof to the lower pipes. A tank space is formed in the main body portion, and a seal wall is integrally formed in the tank space for prohibiting the tank space from communicating with the main pipe. A number of ribs are integrally installed at an inner wall face of the tank space. The oil tank built into the frame of the present invention reduces the number and lengths of welds requiring liquid-tight performance to be as small as possible and as short as possible, and eliminates the need to hermetically seal the main pipe.

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Saitama, Japan

Toshio Matsuno