New drive concept for micro-mobility
BAYK AG specializes in developing electrically assisted cargo bikes as an environmentally friendly alternative for parcel and delivery services, as well as for transporting people in urban areas. This manufacturer, based in Regensburg, Germany, is an international driver of innovation for commercial e-bikes. The EPACs (Electronically Power Assisted Cycles) need to stand up to everyday wear and tear and manage maximum mileage on a single charge. The R+W elastomer coupling allowed this cargo bike specialist to achieve another big advancement during the development process.
The transportation e-bikes from BAYK AG are really up with the times. The increase in online shopping on a regional and national level is causing delivery traffic to increase. Everyone is familiar with scenes of vans of well-known colors double parked while making deliveries, causing blocked roads and traffic jams. The exhaust fumes from the internal combustion engines only add to already polluted city air. Nevertheless, food markets and other local retailers now must meet their customers' desire to have items delivered directly to their doorstep. Courier and parcel services are struggling more and more to hire staff, especially people with a proper driver’s license. On top of all this, the “final mile” is the biggest cost factor when it comes to delivery.
Transportation solutions for the urban jungle
A company from Pielenhofen near Regensburg, Bavaria has presented an elegant solution to this ever-growing problem. Originating from a bicycle factory, BAYK AG now houses a highly skilled manufacturer and developer of zero emission modes of transport. Their e-bike, categorized as a Pedelec 25, is legally classified as a bicycle and may be ridden with a license or car insurance on all roadways approved for bicycles. They can easily avoid traffic jams by using bike routes, bring loading and unloading time windows down significantly, and without generating emissions. This allows them to become the ideal all-purpose carrier for the urban jungle. BAYK has created three product lines to meet market demands: Heavy goods transport using the BRING model, people transport with the CityCRUISER (the VELOTAXI), and the CareCRUISER (the ENJOYABLE BIKE EXPERIENCE) for seniors. Johannes Maier, who is responsible for purchasing & logistics at BAYK AG, puts the advantages in a nutshell: “Our vehicles enable our partners to deliver goods efficiently, reliably and free of emissions, to transport people and to create driving experiences.” As an added bonus, the eye-catching bikes with their modern designs also act as an attractive advertising space.
The toughest demands
What all three product lines have in common is the tough demands in the urban environment. Contrary to private use e-bikes, courier e-bikes for parcel services require daily driver changes, face delivery time pressures, are generally treated with less care, and see high mileage on a variety of terrain. Johannes Maier likes to quote one of his customers, a major parcel service provider: “'The toughest demands on heavy goods vehicles in Germany is seen by the military, but the parcels and express couriers follows in second place'. For us this means that we cannot simply expect our customers to take care of our vehicles, and that we are required to construct and build the vehicles in such a way, that they stand up to the conditions.”
The core of every cargo bike is its drive. To ensure that the drive is fully protected and easy to maintain, BAYK has positioned it inside a protective housing close to the rear axle, which they designed in-house. Each drive shaft has a separate drive motor, delivering a torque of 110 Nm. While this special drive above the rear axle is perfect for the BAYK models, it was not intended for this type of usage by the motor manufacturer, as Johannes Maier explains: “In the utility and cargo bikes business, there is really only one motor manufacturer in Germany that offers standardized hub drives, which are generally built into the wheels. We wanted to find a new approach with our cargo bike, for the extreme kind of demands on motors. We asked ourselves the question of what the power transmission from motor to drive shaft could look like”
Consultation brings a breakthrough
After a lively discussion between the development engineers at BAYK AG and the coupling experts at R+W Antriebselemente GmbH, a ground-breaking new construction for cargo bike drives was created. The idea was sparked by a tip from the BAYK chairmain, who still manages a metals technology company, and the experience of a BAYK designer who studied at Bayreuth University. R+W operates a development partnership with this university as well as the RWTH Aachen. BAYK managing director Johannes Maier describes their cooperation with R+W: “We were delighted that Mr. Bremauer was able to assist us, even though we are certainly not likely to order the largest number of couplings. In the on-site meeting with our construction department, we immediately came up with a solution by using properly configured elastomer couplings that offer a perfect fit to the axle connection.”
Damping, tolerance, assembly
The first prototype for this coupling design was received in March 2019. The benefits of an elastomer coupling are its axial, lateral, and angular misalignment compensations, as well as vibration and shock damping. Elastomer couplings also offer a flexible plug-in design. These properties are very beneficial to BAYK’s requirements, as they reduce wear on the motor and axle connection and dampen vibrations, which promote a longer lifespan of the drivetrain. R+W Studied BAYK’s requirements in detail to offer a precise fit using a precision machined bore and keyway. The coupling’s plug-in design facilitates easy assembly in a tight working space.
More than just elastomers
These days, every BAYK heavy goods cargo bike drive uses two R+W EKL precision elastomer couplings. The backlash free coupling design is defined by the highly precise geometry of the drive jaw contours, which are controlled with a precision plug gauge. The elastomer inserts press-fit into the hubs and create an assembly without any play. This is the only way to guarantee torque transmission without wear and tear under harsh conditions. The elastomer insert is available in various versions with a variety of shore hardnesses, depending on the desired level of damping. The R+W elastomer insert is unique in that is offers a specially developed geometry combined with a selectable shore hardness. Even after an overload, the elastomer insert does not enter its critical plastic range and become permanently deformed. In fact, it returns to its original state and can operate normally. All these features in the standard version of its design are what makes the R+W elastomer coupling so special.
“For us, choosing elastomer couplings from R+W has more than proven itself,” says Johannes Maier in summary. “We are currently in the process of transferring the concept to the VELOTAXI models, because it is so robust and modular. If, for example, a spoke wheel has been bumped or damaged, it can generally be replaced without replacing the motor. We are already becoming successful internationally. The VELOTAXI is currently in the process of being integrated into Paris' public transportation system. Despite the high usage levels with an average of 1,000 km per month and 70 km battery range, we provide a two-year guarantee to our BAYKs. An outstanding quality promise, which we can attribute to our strong partnership with R+W Antriebselemente GmbH.”
Who is behind the application:
As a manufacturer of cargo bikes and bike rickshaws, BAYK AG is an important part of the transportation revolution when it comes to micro-mobility. R+W Antriebselemente GmbH designs and manufactures couplings for machine and plant engineering and is always on the lookout for applications and customers who shape the world with innovative ideas.
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