Electric Trike Product

Overview

An electric trike is a three-wheeled cycle in the delta layout: one steered wheel in front, two driven wheels behind. The configuration trades the lean-to-corner dynamics of a bicycle for static stability, which is why the format dominates among older riders, riders with balance impairments, and short-range cargo users. The machine described here uses a 500 W mid-drive Mid-Drive Motor Unit feeding a rear Rear Axle Assembly through a chain, a 720 Wh Battery Pack under the Rear Cargo Basket, and a steel Step-Through Frame with a step-through main tube low enough to walk through rather than swing a leg over.

How it works

The motor is a brushless DC machine running at 48 V. Inside the Motor Housing, a wound Stator Assembly surrounds a Rotor Assembly carrying 14 Neodymium Magnet poles; three Hall Sensor elements report rotor position to the Motor Controller, which sequences current through six Power MOSFET switches to keep the magnetic field pulling the rotor around. A Helical Gear Pair reduction inside the motor unit drops the motor's 3,000-4,000 rpm to chain speed, and the Motor Output Sprocket drives the rear axle's Differential Input Sprocket at a further 11:36 ratio. Total reduction puts roughly 80 N·m at the axle, enough to start a loaded trike on a 10% grade.

The differential

Two driven wheels on a rigid axle create a problem a bicycle never has: in a corner, the outer wheel travels farther than the inner one. A solid axle would force both wheels to the same speed, scrubbing the tires and making the trike push wide. The Open Differential solves this exactly as a car axle does. Drive torque enters through the Differential Input Sprocket bolted to the Differential Case. Inside, two Spider Gear pinions mesh with two Side Gear outputs, each splined to one Rear Half-Shaft. Going straight, the spiders do not rotate on their own axis and both half-shafts turn together. In a turn, the spiders walk around the side gears, letting one wheel speed up by exactly as much as the other slows, while torque stays split evenly. The whole gearset runs in the Axle Housing on Ball Bearing supports behind Oil Seal closures.

Battery and control

The Battery Pack is a 13s5p array of 65 Li-ion Cell, 18650 cells: thirteen series groups give a 48.1 V nominal stack, five cells in parallel give 15 Ah. A BMS Board balances the series groups, cuts charge at 54.6 V, cuts discharge at 36.4 V, and limits current; a Thermal Fuse backs it up against a heating fault. The pack lives in a lockable Battery Case under the basket floor, held by a Battery Key Latch and charged through a Charge Socket at 2 A, giving a six- to seven-hour full charge.

The Motor Controller is a sinusoidal field-oriented drive built around an Microcontroller on a single Bare PCB board, with the power stage clamped to the finned Controller Case for heat rejection. Phase current is limited to 25 A. Unusually for a cycle controller, it supports a slow reverse gear — useful for backing a loaded trike out of a parking spot, and possible only because a trike does not need to be balanced.

Riding a trike is not riding a bike

Delta trikes corner by steering, not leaning, and the physics punishes bicycle habits. The roll axis runs from the front contact patch to the midpoint of the rear axle, so hard cornering loads the outside rear wheel and can lift the inside one; experienced riders shift their weight into the turn and keep speeds modest. The Cockpit reflects this: a swept-back Swept-Back Handlebar keeps the rider upright over the Seat Assembly, the Thumb Throttle gives fine speed control at walking pace, and the LCD Panel shows speed, assist level and battery state.

Brakes and running gear

The front wheel carries a 160 mm Front Brake Disc gripped by a mechanical Front Brake Caliper; the rear axle carries a contracting Rear Band Brake that doubles as a parking brake, since a trike will roll away on a slope where a bicycle would simply fall over and stay. Both Brake Lever units carry microswitches that cut motor power the moment either lever moves, a requirement under EN 15194. All three Wheel Assembly wheels run pneumatic tires at 2.5-4 bar; the smaller 20-inch rears keep the cargo deck and saddle height low.

Frame and cargo

The Step-Through Frame is welded hi-tensile steel rather than aluminum: the material is cheap, tolerant of point loads from the Rear Subframe, and easily repaired. The Step-Through Main Tube gives a standover height under 400 mm. Behind the seat, the Rear Cargo Basket is rated for 25 kg — placed between the rear wheels, cargo weight adds stability rather than degrading it, which is the quiet advantage of the delta layout over panniers on a two-wheeler.