As a two-wheeler producer, turn your customers into eternal fans.

Secure a competitive edge with Traction‑X’s patented ride comfort and safety advantage.

TRACTION‑X

is a new and patent­ed sys­tem of trans­mis­sion and sus­pen­sion for scoot­ers, which is par­tic­u­lar­ly light and com­pact allow­ing an increase of the wheel diam­e­ter, thus yield­ing  ben­e­fi­cial effects on the dri­ving characteristics.

Illustration of a scooter with Traction-X, a revolutionary drive technology for excellent driving characteristics of scooters.

The design of a scoot­er with Traction‑X pow­er­train suspension

Using the exam­ple of the elec­tric scoot­er illus­trat­ed in Fig­ure, the poten­tial of the new dri­ve con­cept has been illus­trat­ed in an artis­tic representation.

A con­ven­tion­al scoot­er has a so-called pow­er train swing arm, which con­tains motor and sec­ondary dri­ve with­in a rotat­ing lev­el. The seri­ous dis­ad­van­tages of this design have been described in the sec­tion state of the art. Alter­na­tive­ly, the motor is arranged in the cen­ter of the chas­sis or frame, and the pow­er trans­mis­sion to the rear wheel in done via a belt or chain dri­ve. The rear wheel is mount­ed in the chas­sis by means of the swing arm. Nei­ther the use of the instal­la­tion space nor the func­tion are near­ly optimal.

An elec­tric scoot­er equipped with Traction‑X would allow the motor to be rigid­ly mount­ed to the frame and with­in the rear wheel (see illus­tra­tion). The sig­nif­i­cant­ly enlarged rear wheel is also the rock­er arm for shock absorp­tion and damp­ing. The space gained facil­i­tates to accom­mo­date part of the bat­tery below the seat and in front of the rear wheel, so that the footwell is com­plete­ly avail­able to the dri­ver. Dri­ving sta­bil­i­ty, rolling com­fort and agili­ty of the vehi­cle are sig­nif­i­cant­ly improved, as described in sec­tion the inno­va­tion.

The over­all vehi­cle and its out­stand­ing tech­ni­cal improve­ments will rep­re­sent noth­ing less than a tech­ni­cal revolution!

animation traction-x

THE DRIVE

A combination of secondary drive, drive wheel and wheel
suspension

As a pas­sion­ate motor­cy­clist, I am not averse to the com­fort of a scoot­er, but I do not want to accept the sig­nif­i­cant­ly poor­er rid­ing char­ac­ter­is­tics and the deficit in safe­ty com­pared toa motor­bike. As an engi­neer, I have there­fore devel­oped a new  sys­tem that com­bined pow­er trans­mis­sion and wheel sus­pen­sion and thus merges the advan­tages of the motor­cy­cle with the advan­tages of the scoot­er. That is Traction‑X!

I have been a pas­sion­ate motor­cy­clist for most of my life. In addi­tion to enjoy­ing the rid­ing expe­ri­ence, feel­ing close to nature and a feel­ing of free­dom, my enthu­si­asm is also based on a inquis­i­tive­ness for the inner­most tech­ni­cal con­nec­tions of motor­cy­cles, these mar­vels of mechan­ics, electrics and elec­tron­ics. Part of my pas­sion has always been the plea­sure of doing man­u­al work when I dis­man­tled my motor­cy­cles to restore or main­tain them and at the same time reveal their tech­ni­cal secrets. In lat­er years, when I asked for more com­fort, I found that many of the fea­tures of mod­ern scoot­ers suit­ed me, but that I was forced to accept some sig­nif­i­cant­ly poor­er rid­ing char­ac­ter­is­tics com­pared to the motor­cy­cle. As a tech­ni­cal­ly ambi­tious engi­neer, I soon began to think of a remedy.

The fol­low­ing is a brief analy­sis of the require­ments, cir­cum­stances and derived prop­er­ties of the com­pet­ing two-wheeled con­cepts: A motor scoot­er is char­ac­ter­ized in that there should be a splash-proof footwell behind the front wheel and in front of the driver’s seat, allow­ing the rid­er a nat­ur­al and relaxed sit­ting pos­ture. A motor­cy­cle, on the oth­er hand, is char­ac­ter­ized by the fact that the fuel tank and an engine are locat­ed between the legs of the seat­ed rid­er. Both assem­blies must there­fore be posi­tioned fur­ther back in a scoot­er. This would the­o­ret­i­cal­ly increase the scoot­er wheel­base. How­ev­er, since the wheel­base of a two-wheel­er must not become too large, all scoot­ers designed so far were forced to lim­it it by a com­bat­ion of essen­tial­ly two mea­sures. The first mea­sure to reduce the wheel­base is to instal­la­tion of small­er wheels com­pared to the motor­cy­cle. How­ev­er, this has three neg­a­tive effects

  • The dri­ving sta­bil­i­ty of the scoot­er is low­er com­pared to a motor­cy­cle, because the sta­bi­liz­ing angu­lar momen­tum of the small­er wheels is low­er, and con­se­quent­ly the dri­ving behav­ior of scoot­ers is often per­ceived as “wob­bly” and “ner­vous”.
  • The rolling com­fort of the small­er wheels is sig­nif­i­cant­ly worse, since due to their small­er diam­e­ter, even small pot­holes or uneven­ness­es on the road are ful­ly traversed.
  • Dri­ving safe­ty is low­er because the small­er con­tact area or the small­er “tyre swath” means that there is less grip on the road.

The sec­ond pop­u­lar mea­sure to lim­it the wheel­base of any scoot­er is the instal­la­tion of so-called dri­ve train swingarms, which com­bine the motor-gear­box assem­bly with aux­il­iary com­po­nents includ­ing sec­ondary dri­ve as a large sus­pen­sion lever. The neg­a­tive effect of this tech­ni­cal mea­sure is the large unsprung mass, which must be coun­ter­act­ed by a hard spring coef­fi­cient and greater damp­ing of the rear wheel sus­pen­sion. As a result, the over­all sus­pen­sion ride com­fort is com­par­a­tive­ly poor.

The cus­tomer wish­es and require­ments for a relaxed seat­ing posi­tion, weath­er pro­tec­tion, com­fort and a maneu­ver­able vehi­cle, as shown in the fig­ure are there­fore bought with sev­er­al dis­ad­van­tages with con­ven­tion­al motor scooters.

This is exact­ly where the Traction‑X inven­tion comes in, com­bin­ing all the advan­tages of the scoot­er with all the advan­tages of the motor­cy­cle, “the best of both worlds”, so to speak..

PROOF OF CONCEPT

The Demonstrator

In coop­er­a­tion with the Insti­tute of Auto­mo­tive Engi­neer­ing at the Cologne Uni­ver­si­ty of Applied Sci­ences, a scaled demon­stra­tor of Traction‑X has been cre­at­ed. This 3D-print­ed mod­el, ani­mat­ed by means of a micro-PC, is proof of the fea­si­bil­i­ty i.e., of the Traction‑X concept.

Details can be read at the blog­post Demon­stra­tor.

TRACTION‑X @ LaborX Hamburg

Last month, Traction‑X was a guest of start-up con­sul­tant Dr Jan Evers in Hamburg’s LaborX. His pod­cast “Ideen­couch” is a very spe­cial appre­ci­a­tion for all start-ups and bud­ding entre­pre­neurs. We received a trea­sure trove of tips and good expert advice in the con­ver­sa­tion. In addi­tion, we had a lot of fun!

Many thanks to Jan and his team at the LaborX!

Lis­ten for yourself!

The pod­cast episode

The pod­cast episode on Spotify

STATE OF THE ART

What is the technical status quo of two-wheeler technology?

Con­ven­tion­al motor­cy­cles often have a sec­ondary dri­ve by means of a link chain or toothed belt. The state-of-the-art in dri­ve tech­nol­o­gy for these motor­cy­cles is the func­tion­al and spa­tial sep­a­ra­tion of the dri­ve shaft and swing arm axis, in com­bi­na­tion with the cen­tral mount­ing of a con­ven­tion­al rear wheel. The dis­ad­van­tage of this design is the vari­abil­i­ty of the dis­tance between the chain sprock­et and the rear wheel sprock­et in the chain dri­ve or between the front and rear pul­ley in the belt dri­ve. The deflec­tion of the rear wheel when dri­ving over a bump leads to notice­able reper­cus­sions in the dri­ve train, i.e. on engine speed and torque.

The state of the art in scoot­er dri­ve trains is the com­bi­na­tion of a so-called swing arm dri­ve train with a con­ven­tion­al rear wheel that has a cen­tral mount­ing. A swing arm dri­ve train is an inte­gral design of engine, trans­mis­sion and rear wheel swing arm. The motor and dri­ve hous­ing is swiv­el-mount­ed in the motor­cy­cle frame and fol­lows the move­ments dur­ing the com­pres­sion and rebound. The dri­ve shaft and swing arm are also func­tion­al­ly and spa­tial­ly sep­a­rat­ed. The dis­ad­van­tage of this design is the large unsprung mass, i.e. the large moment of iner­tia, which results in a mod­er­ate response and com­fort of the rear wheel sus­pen­sion. The advan­tage of this design is the con­stant dis­tance between the chain sprock­et and the rear wheel sprock­et in the chain dri­ve or between the front and rear pul­ley in the belt drive.

Diagram showing the advantages, requirements and disadvantages of conventional two-wheel drive technology
Illustration Traction-X, the new development of the patented concept for drive and suspension.

THE PATENT

Click here to access files at the Ger­man Patent and Trade­mark Office

The inven­tion on which Traction‑X is based is a device for trans­mit­ting the dri­ve torque from the engine of a wheeled vehi­cle to its dri­ve wheel and for shock-absorb­ing and resilient sus­pen­sion of the dri­ve wheel itself. An extreme­ly com­pact design is achieved, which fea­tures great advan­tages espe­cial­ly for motor scooters.

The inven­tion of the Traction‑X was moti­vat­ed by the task to devel­op a com­pact unit for pow­er-trans­mis­sion and wheel sus­pen­sion for a motor scoot­er, which meets the fol­low­ing requirements

  • A short wheel­base of the two-wheel­er in com­bi­na­tion with a small turn­ing cir­cle and a low moment of iner­tia around its ver­ti­cal axis were sought to real­ize, with the aim to achieve good agili­ty and mobil­i­ty of the scooter.
  • A large wheel diam­e­ter was sought to facil­i­tate, so that dri­ving sta­bil­i­ty, road-hold­ing, and ride com­fort are sig­nif­i­cant­ly improved com­pared to con­ven­tion­al scooters.
  • The mass of the motor-gear unit should have no influ­ence on the shock-absorb­ing and spring-loaded wheel sus­pen­sion, i.e. the unsprung mass of the entire wheel sus­pen­sion should be small, regard­less of how large the motor-trans­mis­sion unit is.

Tech­ni­cal­ly, the Traction‑X inven­tion could be referred to as a “dri­ve arm wheel sus­pen­sion”. It com­bines the func­tion­al­i­ty of three tech­ni­cal components

  1. the sec­ondary dri­ve from the motor or trans­mis­sion out­put to the dri­ve wheel, depend­ing on whether it is an inter­nal com­bus­tion engine or an elec­tric motor drive
  2. the swing arm or the rock­er arm of the resilient sus­pen­sion, and
  3. the dri­ve wheel itself.

For this pur­pose, Traction‑X fea­tures a very large wheel bear­ing, which has the same dimen­sions as the wheel rim itself, so that there is an inner ring inside the wheel, which is not rotat­ing w.r.t. wheel rim and tire. The wheel is sup­port­ed like a rock­er arm by means of a spring strut and an axle. This axle or wheel lever shaft at the same time is the dri­ve shaft for the wheel itself. For this pur­pose, it has a dri­ve gear­wheel with exter­nal teeth, which is in engage­ment with an inter­nal tooth­ing con­nect­ed to the out­er wheel rim. The dri­ve shaft is dri­ven at an out­er end by a motor gear unit, for exam­ple via a chain, belt or spur gear dri­ve. For its sec­ond func­tion as a swing arm, the dri­ve shaft is mount­ed at its out­er ends via plain or roller bear­ings into the frame of the two-wheel­er. The inner com­po­nent of Traction‑X, which is non-rota­tion­al w.r.t. the wheel rim, is mount­ed sta­t­i­cal­ly deter­mined onto the com­bined dri­ve and wheel lever shaft by means of a ball bear­ing and a nee­dle bear­ing. The heli­cal gear unit and the bear­ings inside the hous­ing made of the inner wheel ring and wheel rim can be sealed to the out­side by means of radi­al shaft seals. Thus, the entire Traction‑X dri­ve arm wheel sus­pen­sion can be ful­ly oil-lubricated.

In a sec­ond vari­ant of the inven­tion the wheel is sup­port­ed by means of three rollers, which engage and roll in a ring groove. This replaces the very large ball bear­ing. Again, this arrange­ment results in an inner com­po­nent that is not rotat­ing w.r.t. wheel rim and tire. The roller cas­ings pro­trud­ing into the inside of the wheel slight­ly reduce the inte­ri­or clear­ance, but yield some coun­ter­ing advan­tages. They can be used in a sealed vari­ant that is lubri­cat­ed for life. With­in a scoot­er of mod­er­ate dri­ve pow­er, oil bath lubri­ca­tion can be dis­pensed with, so that the two large radi­al shaft seals can be omit­ted. This in turn reduces the fric­tion­al moment in the system.

The use case of Traction‑X with­in a scoot­er was the moti­va­tion of the inven­tor. There­fore, the advan­tages of the inven­tion for this appli­ca­tion will be worked out in the sec­tion Inno­va­tion.

Drive-Train Swing-Wheel

Caption references
1 com­bined dri­ve and swing-wheel shaft
1a par­al­lel key
1b keyway
2 retain­ing ring and ring groove
3 grooved ball bear­ing (mov­able)
4 deep groove ball bear­ing (fixed)
5 cylin­der screw
6 left hous­ing cover
7 gear wheel with exter­nal teeth
8 hous­ing cov­er and right-hand side wheel hub
9 right-hand side wheel hub
10 nee­dle bear­ing (mov­able)
11 radi­al shaft seal­ing ring
12 deep groove ball bear­ing (fixed)
13 dri­ve sprock­et for chain drive
14 shaft nut with lock wash­er and shaft groove
15 cylin­der screw
16 right hous­ing cover
17 grooved ball bearing
18 radi­al seal­ing ring wheel cir­cum­fer­ence right
19 tire
20 wheel rim
21 radi­al seal­ing ring wheel cir­cum­fer­ence left
22 dri­ve gear with inter­nal toothing
23 shaft nut with lock wash­er and shaft groove
24 radi­al seal­ing ring
25 bolt­ed inter­face of the hub halves
26 screwed con­nec­tion with sus­pen­sion strut axle
27 riv­et­ed con­nec­tion of wheel rim to dri­ve gear 22
28 secur­ing screw for wheel bear­ing out­er ring
29 secur­ing wash­er for wheel bear­ing out­er ring
30 secur­ing screw for wheel bear­ing inner ring
31 secur­ing wash­er for wheel bear­ing inner ring
32 spring strut axis
33 spring strut with damper cartridge

Drive-Train Roller-Ring Swing-Wheel

Caption references
101 com­bined propul­sion and swing-wheel shaft
101a ring groove
101b ring groove
102 retain­ing ring and ring groove
103 deep groove ball bear­ing (float­ing) for chassis
104 deep groove ball bearing
105 cylin­der screw
106 left hous­ing cover
107 dri­ve gear with exter­nal teeth
108 hous­ing cov­er or right-hand side wheel hub
109 hous­ing cov­er or left-hand side wheel hub
110 track roller 1
111 nee­dle bear­ing (mov­able)
112 radi­al shaft seal­ing ring
113 deep groove ball bear­ing (fixed)
114 chain dri­ve sprocket
115 shaft nut with lock wash­er and shaft groove
116 cylin­der screw
117 right-hand side hous­ing cover
118 secur­ing ring for track roller 1
119 radi­al shaft seal­ing ring wheel cir­cum­fer­ence left
120 tire
121 wheel rim
122 radi­al shaft seal­ing ring wheel cir­cum­fer­ence right
123 dri­ve gear with inter­nal toothing
124 shaft nut with lock wash­er and shaft groove
125 radi­al shaft seal­ing ring
126 screwed con­nec­tion of two wheel rim halves
127 screwed con­nec­tion with spring strut axle and track roller 2 housing
128 riv­et­ed con­nec­tion of wheel rim to dri­ve gear 123
129 track roller 2
130 secur­ing ring for track roller 2
131 sus­pen­sion strut axle
132 screwed con­nec­tion for track roller 3 housing
133 track roller 3
134 secur­ing ring for track roller 3
135 sus­pen­sion strut with damper cartridge

THE INNOVATION

A compact secondary drive unit for a scooter

Traction‑X is a new and patent­ed vehi­cle dri­ve con­cept that enables small unsprung mass­es, extreme­ly effi­cient use of space and large wheel diam­e­ters, which is par­tic­u­lar­ly advan­ta­geous for scooters.

Verbesserungen durch Traction-X, einer revolutionären Antriebstechnologie für exzellente Fahreigenschaften von Motorroller.

Traction‑X is a new pow­er train con­cept for scoot­ers that offers great advan­tages and that can option­al­ly be used for oth­er types of wheeled vehi­cles. The basis is the patent DE 10 2011 117 388 A “Device for the com­bi­na­tion of sec­ondary dri­ve, rock­er arm and dri­ve wheel of a wheeled vehicle”.

When used for motor scoot­ers, the Traction‑X inven­tion has the fol­low­ing com­pelling advan­tages over dri­ve sys­tems with dri­ve unit rockers:

  • much small­er unsprung mass,
  • sig­nif­i­cant­ly larg­er wheel diam­e­ter and
  • short­er wheelbase.

Traction‑X thus com­bines all the advan­tages of the scoot­er with all the advan­tages of the motorcycle.

  1. A scoot­er equipped with Traction‑X has a small turn­ing cir­cle and a com­par­a­tive­ly low mass moment of iner­tia around its ver­ti­cal axis, because of which the scoot­er has out­stand­ing agili­ty and very good maneu­ver­abil­i­ty. At the same time, the large pos­si­ble wheel diam­e­ters give the scoot­er out­stand­ing dri­ving sta­bil­i­ty com­pared to con­ven­tion­al scoot­ers and sig­nif­i­cant­ly improved ride com­fort that is on a par with a motorcycle.
  2. Com­pared to scoot­ers with a con­ven­tion­al swing arm dri­ve train, the rear wheel sus­pen­sion of a motor scoot­er equipped with Traction‑X has sig­nif­i­cant­ly low­er unsprung mass­es, which enable sen­si­tive respon­sive­ness of the sus­pen­sion and damp­ing. The required tire air pres­sure can also be reduced with Traction‑X, so that the sen­si­tiv­i­ty of the sus­pen­sion of this com­po­nent is also con­sid­er­ably better.
  3. In both embod­i­ments of Traction‑X, a free space remains with­in the torus-shaped swing arm, which can favor­ably be used to accom­mo­date the elec­tric motor, the dri­ve motor gear­box or parts there­of, so that an extreme­ly com­pact two-wheel dri­ve enti­ty is cre­at­ed. Thus, the footwell of the scoot­er is ful­ly avail­able again, which sig­nif­i­cant­ly increas­es the driver’s comfort.
  4. The dri­ving sta­bil­i­ty is sig­nif­i­cant­ly bet­ter than with con­ven­tion­al scoot­ers due to the high­er gyro­scop­ic moments of the larg­er wheels, i.e. just as great as with a motorbike.
  5. The dri­ving safe­ty is high­er due to the larg­er con­tact area of the wheel with the road, i.e. the larg­er “tyre swath”, because thus the adhe­sion between tyre and road is also greater.

The favor­able fea­tures of Traction‑X have been described and dis­closed in the patent doc­u­ment, in the draw­ings and in the claims, so that they may eas­i­ly be applied indi­vid­u­al­ly or in any com­bi­na­tion. The aim is the ben­e­fi­cial imple­men­ta­tion of the inven­tion in var­i­ous embodiments.

The inven­tion Traction‑X can there­fore also be used to design a bicy­cle of the future. For instance, there is the pos­si­bil­i­ty of com­bin­ing the rock­er arm axis of the rear sus­pen­sion with the ped­al crank axis into a com­mon and inte­gral com­po­nent. A mul­ti-pur­pose axis like this would save weight and increase the sta­bil­i­ty of the wheel sus­pen­sion. This par­tial aspect of the inven­tion is already pro­tect­ed as an indi­vid­ual claim of the patent. The unique sell­ing points for any future bicy­cle could there­fore be

  • light weight due to ped­al crank bear­ing = swing arm bearing
  • increased dri­ve com­fort due to a con­stant dis­tance between rear wheel axle and ped­al crank axle dur­ing the com­pres­sion of the rear suspension