Vehicle body frame structure of straddle-type vehicle
View Patent ↗Provided is a vehicle body frame structure which can reduce a burden in assembly of a straddle-type vehicle. The structure comprises a head pipe; and a pair of main frames extending rearward from the head pipe and outward in a vehicle width direction such that the main frames are spaced apart from each other in the vehicle width direction. Rear portions of the pair of main frames are detachably coupled to each other in the vehicle width direction via a coupling member. The pair of main frames include a pair of front frame members including respective first mounts to which a drive unit of the vehicle is mounted, and a pair of respective rear frame members located rearward relative to the front frame members. The pair of rear frame members have a stiffness lower than that of the front frame members in the vehicle width direction.
1. A vehicle body frame structure of a straddle vehicle comprising:
a head pipe; and
a pair of main frames extending rearward and outward in a vehicle width direction from the head pipe in such a manner that the main frames are spaced apart from each other in the vehicle width direction,
wherein rear portions of the pair of main frames are detachably coupled to each other in the vehicle width direction via a coupling member,
wherein the pair of main frames include a pair of front frame members including first mounts, respectively, to which a drive unit of the vehicle is mounted, and a pair of rear frame members located rearward relative to the front frame members, respectively,
wherein the pair of rear frame members have a stiffness lower than that of the front frame members in the vehicle width direction,
wherein the pair of main frames include a pair of pivot bracket members extending downward from rear end portions of the rear frame members, respectively,
wherein the coupling member is placed between the pair of pivot bracket members, coupled to the pair of pivot bracket members, and coupled to a rear surface of the drive unit, and
wherein a swing arm is mounted to the pair of pivot bracket members and the coupling member.
2. The vehicle body frame structure of the straddle vehicle according to claim 1 ,
wherein each of the pair of front frame members includes a plurality of rod-shaped frames placed in different directions, the plurality of rod-shaped frames of one of the front frame members and the plurality of rod-shaped frames of the other front frame member are arranged along a pair of virtual planes extending rearward from the head pipe to be spaced apart from each other in the vehicle width direction from the head pipe, and the plurality of rod-shaped frames of each of the pair of front frame members are coupled to each other to form a trellis structure, and
wherein each of the pair of rear frame members is constituted by a single rod-shaped frame extending rearward linearly from the front frame member.
3. The vehicle body frame structure of the straddle vehicle according to claim 1 ,
wherein the pair of rear frame members extend independently of each other in such a manner that the rear frame members are permitted to be deformed inward in the vehicle width direction.
4. The vehicle body frame structure of the straddle vehicle according to claim 1 ,
wherein the drive unit includes a second mount located rearward relative to the front frame members, and
wherein the second mount is coupled to the pair of pivot bracket members via the coupling member, and a rear suspension is coupled to the coupling member.
5. The vehicle body frame structure of the straddle vehicle according to claim 4 ,
wherein each of the rear frame members is placed between the first mount and the second mount in a vehicle length direction.
6. The vehicle body frame structure of the straddle vehicle according to claim 1 ,
wherein each of the front frame members includes an upper frame extending rearward from an upper portion of the head pipe, a lower frame extending rearward from a lower portion of the head pipe, and a connection frame connecting the upper frame to the lower frame substantially vertically, and
wherein each of the rear frame members extends continuously rearward from one of the upper frame and the lower frame.
7. The vehicle body frame structure of the straddle vehicle according to claim 1 ,
wherein each of the first mounts is placed at an intermediate portion of the front frame member in a vehicle length direction.
8. The vehicle body frame structure of the straddle vehicle according to claim 1 ,
wherein each of the first mounts includes a plurality of first mount members which are placed to be spaced apart from each other.
9. The vehicle body frame structure of the straddle vehicle according to claim 1 ,
wherein a rear portion of the drive unit is mounted to the pair of pivot bracket members.
10. The vehicle body frame structure of the straddle vehicle according to claim 9 ,
wherein the coupling member is placed between the pair of pivot bracket members and detachably coupled to the pair of pivot bracket members, and
wherein the rear portion of the drive unit is fastened to the coupling member by use of a fastener member inserted into the coupling member in a vehicle length direction.
11. The vehicle body frame structure of the straddle vehicle according to claim 1 ,
wherein the pair of rear frame members extend linearly from the pair of front frame members, respectively, and the pair of pivot bracket members extend linearly from the pair of rear frame members, respectively.
12. The vehicle body frame structure of the straddle vehicle according to claim 1 , further comprising:
a pair of rear frames extending rearward from the pair of main frames, respectively,
wherein the coupling member and the pivot bracket members are coupled to each other at locations where a pivot shaft is coupled, the swing arm being pivotally mounted to the pivot shaft, and at locations where the rear frames are coupled.