MOTORCYCLE FRAME

Autor: Ol`khovikov Viktor Vladislavovich

Contact: rosting@comp-net.ru

The patent refers to motorcycles, in particular, to motorcycle frames. The motorcycle frame includes a carcass 1 for fastening of front suspension 2 and back suspension 3 with rocking levers. Suspensions 2, 3 interact with their own shock-absorbers 5, 9. Shock-absorbers 5, 9 are connected sequentially in one body 4. Body 4 has a capacity of movement along the carcass 1 guides 6 and blocking of the above movement as well. The proposed technical solution is aimed at the regulation of the suspension hardness, in particular at the decreasing of the hardness of front and back suspensions to increase the ride comfort.

The patent refers to engines and can be used in production of motorcycles and mopeds.  

Technique level

The designs of omega-type frames with two shock absorbers on the front and back suspensions are known. The example is “Yamaha CTS1000”. Its frame contains the omega-type carcass, to which the front lever suspension with the shock absorber is fastened as well as the back pendulum suspension with shock absorber and a progressive characteristics

This design has two shock absorbers fastened rigidly to the frame. They do not interact with each other. Due to it each suspension has its own hardness characteristics that is determined by the design peculiarities. Here, the comfort and safety of ride are ideal at a very narrow range of the suspension adjustment. This range depends not only on the amount of persons riding a motorcycle (2 or 1) but also on the rider’s mass that makes the industrial adjustment of the suspension more difficult. Besides, there is a danger in case of head-on-crash (border or hummock): first the front part of the motorcycle is thrown up, then, when it goes down, the back part is thrown up. Here, a rotatory moment appears that tends to turn the motorcycle over.  

The essence of the patent

The main objective, at which the patent is aimed, is to increase the comfort and safety of the motorcycle ride. This objective is solved by the location of shock absorbers of the front and back suspension in the same body. It can move relative to the carcass frame in the direction of the front or back suspensions. It will decrease, if necessary, the hardness of the front or back suspension. As for the “Jamaha GTS1000”, the shock absorber of each suspension is fastened rigidly to the frame carcass. In this case the hardness characteristics is unchangeable under any conditions that influences negatively the comfort and safety of the ride under the increased loadings on the motorcycle suspension.

The set aim is achieved by that the motorcycle frame consists of a carcass to fasten the front and back suspensions, each of them interacting with the corresponding shock absorber. The shock absorbers are connected sequentially with each other and built-in in one body that can move along the guides fastened rigidly to the carcass. It is possible to block the sliding of the shock absorbers along the above carcass guides.

This design will allow, if necessary, for decreasing of the hardness of the front and back suspensions. Thus, in case of the head-on-crush (the dimensions of the obstacle are less than the motorcycle base length), the front suspension displaces the shock absorber body to the back suspension and then the back suspension displaces the shock absorber body to the front one. Here, the hardness of each suspension decreases and due to it, in case of obstacle overcoming, only the suspension moves. The motorcycle itself is subjected to the minimum effect that makes the ride more comfortable and safe.

In case of simultaneous effect of the both suspensions on the shock absorber, each suspension effects on its own shock absorber. It makes the characteristics of each suspension harder as compared to the consequent effect.  

List of drawings

Fig.1 presents the design of the omega-type frame with a carcass, suspensions and shock absorbers.

Fig.2 presents the principle kinematic scheme of the suspensions and frame shock absorber performance in case of obstacle overcoming (a, b, c, d) at the simultaneous effect (e), braking (f) and acceleration (g).

Data verifying the possibility of the patent implementation.

The frame design consists of a carcass 1, front suspension 2, back suspension 3, shock absorber body 4, small shock absorbers 5 and 9, sliding guide 6, lever systems 7 and 10, axis of wheels fastening 8, axis of suspensions fastening 2, 3, and 11.

The shock absorber body 4 is capable to move forward and backward along the guides 6 fastened rigidly to the body 1.

The movement of suspensions 2 and 5 is transmitted by small shock absorbers 5 and 9 though the lever systems 7 and 10.

Shock absorber performance

The shock absorber with suspensions and frame operates in the following way: when the suspension 2 moves upward (fig. 2,b) through the lever systems 7, it effects on the small shock absorber 5. It, in its turn, compresses and effects on the shock absorber body 4. Due to this effect, the body moves along the guides 6 in the direction of the suspension 3 initiating the small shock absorber 9 compression. Then the system turns into the initial state (fig. 2,c).

When the suspension 3 moves upward (fig. 2,d) through the lever systems 10, it effects on the small shock absorber 9. It, in its turn, compresses and effects on the shock absorber body 4. Due to this effect, the body moves along the guides 6 in the direction of the suspension 3 initiating the small shock absorber 9 compression. Then the system turns into the initial state (fig. 2,c).

When the suspensions 2 and 3 move upward simultaneously through the lever systems 7 and 10, they effect on the small shock absorbers 5 and 9. They, in their turn, compress and effect on the shock absorber body 4. At that, the shock absorber body 4 does not displace relative to the carcass 1 along the guides 6 in the direction of any suspension because it is subjected to the equal effect of small shock absorbers 5 and 9 (fig. 2,e).

At the consequent and simultaneous downward movement of the suspensions the order of the shock absorber 4 interaction with the suspensions 2 and 3 and carcass 1 remains the same, but the direction of individual parts movement changes into opposite one.

At a sharp braking, the blocking system of the shock absorber body 4 sliding along the guides 6 is actuated (fig. 2,f). At this moment, the suspension 2 is subjected to the increased loading. As a result of it, the suspension 2 displaces upward relative to the carcass 1 effecting through the lever systems 7 on the small shock absorber 5. The suspension compresses it but does not displace the shock absorber body 4 that makes the suspension 2 harder and prevents the typical motorcycle peck forward.

At a sharp acceleration the blocking system of the shock absorber body 4 sliding along the guides 6 is also actuated (fig. 2,g). Here, the suspension 3 is also subjected to the increased loading. As a result of it, the suspension 3 displaces upward relative to the carcass 1 effecting through the lever systems 10 on the small shock absorber 9. The suspension compresses it but does not displace the shock absorber body 4 that makes the suspension 2 harder and prevents its excessive collapse.  

Patent formula

The motorcycle frame contains a carcass to fasten the front and back suspensions interacting with their own shock absorbers. It has the following peculiarities: the shock absorbers are connected sequentially with each other and built-in in one body that can move along the guides fastened rigidly to the carcass. It is possible to block the shock absorber body sliding along the carcass guides.

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