Frame of riding type motorcycle

Abstract

The invention relates to a riding-type motorcycle frame, which essentially comprises a stand tube (1), an inclined supporting tube of an engine (21), a main girder (4), a left and a right middle tube(15 and 19), a left and a right upper tube (12 and 5), a left and a right supporting tube (10 and 8), as well as an upper and a lower horizontal tube (20 and 16); bending parts on middle parts of theleft and the right upper tubes (12 and 5) which extend backward and upward are connected with a horizontal tube (6); a left and a right reinforcing plates (11 and 7) between the left and the right uppertubes (12 and 5) and the left and the right supporting tubes (10 and 8) are moved to the bending parts which are close to the middle parts on the left and the right upper tubes (12 and 5). By improvi ng structure design for the key connecting parts of the frame, the invention is more reasonable in frame structure, and more reliable in intensity and rigidity; the invention effectively reduces thevibration of the entire motorcycle, improves the riding comfort, and expands the service life of the entire frame.

Description

technical field [0001] The invention belongs to the technical field of motorcycles, and in particular relates to a motorcycle frame. Background technique [0002] At present, the frame of the well-known ride-on motorcycle on the market is also called a single cradle frame. The left and right upper tubes, left and right support tubes are welded, among which the main beam, standpipe, engine diagonal support tube, left and right middle tubes and upper and lower horizontal tubes constitute the front frame of the frame; left and right upper tubes, left and right middle tubes and left and right support tubes constitute The middle and rear frame of the frame. However, in use, we found that the existing riding motorcycle with a single-cylinder 250 engine mounted on it, when the engine speed was higher than 6000rpm, the vibration of the whole vehicle was very severe, and the riding comfort was poor. After analyzing the vibration characteristics of the frame, it is concluded that th...

AI Technical Summary

Problems solved by technology

However, in use, we found that when the engine speed is higher than 6000rpm, the existing riding motorcycle with a single-cylinder 250 engine mounted on it, the vibration of the whole vehicle is very severe, and the riding comfort is poor.

After analyzing the vibration characteristics of the frame, it is concluded that the frame is in the range below 200Hz, that is, the engine speed is below 6000rpm, the seat cushion, pedals, handlebar Z direction (up and down direction), handlebar X direction (front and rear) direction) the acceleration response of the four measuring points is small, and the frame vibration is small; while in the range higher than 200Hz, that is, the engine speed is higher than 6000rpm, the acceleration response of the four measuring points is relatively large, and there are two The larger the peak value, the stronger the vibration of the frame, that is to say, there is an unreasonable structural problem at the joints associated with the handlebars, pedals, and seat cushions on the frame, which causes the entire frame to vibrate at high speeds. The severe vibration under the environment affects the ride comfort of the vehicle

[0003] In addition, when the existing riding motorcycle frame used to hang the single-cylinder 250 engine is suddenly braked during the steering process, the connection between the lug and the upper horizontal tube, the upper horizontal tube and the left and right middle tubes will be installed on the rear suspension. The joints are prone to damage first

After analyzing the static strength of this frame by CAE, it is found that the overall stress level of the frame is lower than 50MPa under the steering braking condition, the connection between the lugs installed on the rear suspension and the upper horizontal tube, and the connection between the upper horizontal tube and the left and right There is a relatively large stress at the joint of the middle pipe (the maximum stress is about 232Mpa), which is greater than the dynamic yield stress (that is, higher than 117.5MPa). When braking suddenly during the steering process, it will be subject to a large centrifugal force and a large instantaneous impact load. The above defects lead to unreliable strength of the entire frame and affect the service life of the frame.

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