August 2021

n TRANSPORTATION Precision motor-maker comes up with ‘invisible’ e-bike propulsion T he Swiss precision drive specialist maxon motor has used its expertise to develop an electric bike drive system that is almost invisible and weighs only 3.5kg, including its battery. Maxon has spent “several years” developing the Bikedrive Air technology which it plans to sell to bicycle manufacturers to incorporate into their frames, and as conversion kits for existing bikes. The version for bicycle OEMs consists of a mid-mounted 220W/30Nm brushless internal-rotor motor with a single-stage planetary gearhead, a 250Wh 36V lithium- ion battery that can be integrated into the frame, and a controller. It will allow the manufacturers to offer electric road bikes weighing just 10.5kg and trail bikes weighing 15.5kg. A “unique” freewheel technology will provide electrical assistance only when needed, and is said to result in a user experience that is “like riding with a tailwind”. The electrical assistance can be activated at the press of a button. When the rider exerts more pressure on the pedals, a torque sensor responds immediately to deliver more power. Speeds of up to 25km/h are possible. The 250Wh battery weighs just 1.4kg and takes 3.5h for a full charge. An extra 250Wh battery can be mounted magnetically on the frame or stored in a backpack to double the range. The converter kit version uses a motor with ironless windings mounted in the bike’s rear wheel, in conjunction with a frame- mounted 360Wh, 48V battery that takes two hours to charge. It is claimed to accelerate from 0 to 20mph (32km/h) in less than 3s and can carry an average-weight (175lb/80kg) cyclist up a 10% incline to an altitude of 3,200ft (975m) in less than 30 minutes. The motor delivers up to 50Nm of torque and is said to operate with a typical efficiency of 85%. Riders can choose the torque level they require via a handle-bar mounted “powergrip”. LEDs indicate the battery status and the motor temperature. The conversion kits are priced from CHF 2,100-2,500 (£1,655-1,971), depending on the wheel and battery sizes. Maxon has also developed an iOS/Android app for the Bikedrive that allows cyclists to tune support levels and select ride profiles. The first OEM bike manufacturers have started to integrate the new drive into their bicycles and these are expected to go on sale later this year. n www.maxonbikedrive.com Bicycle manufacturers can integrate maxon’s BikeDrive Air propulsion system into their bikes so that the system is almost invisible. The drive components are hidden inside the bicycle’s frame PROCESS CONSULTING ENGINEERING SOFTWARE Let’s focus on usability. EPLAN Platform 2022 It’s in your hands!