Yamaha PW series Drive Unit (2016)

March 29, 2016

Smooth and Powerful

The overall concept for the PW series is "smooth and powerful". While providing the smooth electric-assist expected by many general e-Bike users, our systems are equipped with powerful support and a natural, "organic" assist feel in the high speed range as well. The "triple sensor system" is what enables this "organic assist feel" that has been part of Yamaha's development philosophy from the start.The three sensors refer to: 1. a torque sensor that detects pedaling power, 2. a speed sensor that detects the bicycle's speed, and 3. a crank sensor that detects the number of rotations through pedaling. The sensors instantly detect the running conditions and the movement of the rider with precision, allowing for a smooth and powerful assist.One aim of the PWseries is to win over the hearts of athletic, sporty cyclists, in addition to the every-day users.

1. Drive Unit

There are two main advantages in center mount type units. First, the gears originally equipped to the bicycle can be utilized as a part of e-Bike systems, allowing for optimal motor performance.
Second is weight distribution. Centralization of mass leads to a natural weight balance while riding and while stopped, retaining the superior weight distribution of a bicycle.

We have succeeded in developing one of the world's smallest and lightest drive units. This involves the direct transmission of the motor power to the crankshaft, providing for a minimal exterior design.
The high-power motor has ample amounts of low-down torque, making electrical assist on hills and gravel roads – under the hardest of conditions - extremely powerful.

Center mount unit (bottom bracket motor)
Support up to 25km/h
Motor
- Rated power: 250W
- Peak torque: 80 Nm
- Continuous maximum torque: 70 Nm
- Direct transmission of the motor power to the crankshaft
Sensors
- Torque sensor, speed sensor, crank sensor
Weight
- 3.5kg (excl. Drive Sprocket)

The compact, light weight center mount unit
There are two main advantages in center mount type units. First, the gears originally equipped to the bicycle can be utilized as a part of e-Bike systems, allowing for optimal motor performance.Second is weight distribution. Centralization of mass leads to a natural weight balance while riding and while stopped, retaining the superior weight distribution of a bicycle.
We have succeeded in developing one of the world's smallest and lightest drive units. This involves the direct transmission of the motor power to the crankshaft, providing for a minimal exterior design.The high-power motor has ample amounts of low-down torque, making electrical assist on hills and gravel roads – under the hardest of conditions - extremely powerful.

Support Level

Mode	HIGH	STD	ECO	ECO+
Instantaneous maximum value at pedal crank axis	< 2.8	< 1.9	< 1.0	< 0.5


Image of the torque at starting	Motor torque / Input torque

Notes:These figures are standard numerical values of YAMAHA.These figures may change depending on the differences in a characteristic setup, and the differences in vehicles composition

2.The triple sensor system

The "triple sensor" system is what holds the product concept of "smooth and powerful" in place. The three sensors are the: 1. a torque sensor that detects pedaling power, 2. a speed sensor that detects the bicycle's speed, and 3. a crank sensor that detects the number of rotations through pedaling. By equipping the three sensors to the unit, the rider is supported by continuous assistance under every riding condition. The constant assist is what allows the "smooth and powerful" concept to come alive during the ride.
The torque sensor has great response, resulting in an optimal assist timing through fine-tuning the motor control.

3. Four Drive Modes +Off Mode +walk assistance

The assistance modes are available in "High", "Standard", "Eco", and "+Eco".
Optimized assist control for each gear enables powerful and natural assist power with a long cruiser range.
Four assist modes (or five, including 0 assist) are available so that the optimum assist level can be selected according to use. The Assist Mode can be selected with ease by using the switch

Mode	Assistance profile
High	Provides a constant and powerful assistance. Perfect for riding uphill.
STD	Satisfies both power and cruising range. Recommended for daily use.
ECO	Saves energy for an extended cruising range. Best used when cruising on a flat road.
+ECO	Range of +Eco mode will be approximately 30% longer than Eco mode.
OFF*	Allows you to ride without power assist while switch functions remain enabled.

* The OFF mode is available only on the LCD display.

Improvement of Walking Assistance

Make it easier to push the bike up on slopes.

Maximum torque of walking assistance is strengthen to 70Nm.
Gradually reaching the maximum torque while pushing the switch.
Speed limit is 6km/h at the highest gear and going lower as shifts down

4. LCD multi function Drive Controller

Easy to use in any scene

One of the design philosophies of the PW series, in addition to the "smooth and powerful" concept, is "ease of use". This is reflected on the design of the main switch. The LCD multi function Drive Controller is equipped with the following functions.

By pressing the "Pushing assist switch", an appropriate level of assist for walking is available.
The display can be removed to prevent theft.
For sport-riding oriented riders that monitor their cadence while riding, a cadence meter is available.
The unit is designed to provide satisfaction to riders of all types, including those with a strong inclination towards "riding quality".

More features

Drive control: 4 selectable assist modes
Battery capacity indicator:
- 10 scale bar
- Digital display (in %)
Assist power meter
Cycle computer
Range meter
Cadence meter
Clock
Removable display
USB connector is added:
- 5V electric power can be supplied to connected device.
- Parameter writing tool can be connected.

5. Three Types of Battery


Down Tube Type Lithium-ion battery: 36V, 400Wh Charging time: approx. 3.5hrs Weight: 2.9kg	Rear Carrier Type 500Wh Lithium-ion battery: 36V, 500Wh Charging time: approx. 4hrs Weight: 3.8kg	Rear Carrier Type 400Wh Lithium-ion battery: 36V, 400Wh Charging time: approx. 3.5hrs Weight: 2.9kg

Select between "down tube type" and "rear carrier type" to fit the application.
We have a 400Wh lineup for the down tube type and 500Wh and 400Wh lineup for the rear carrier type.

Select where you load your battery pack from 2 locations

The battery pack employs a large capacity cell (highest spec available) compared to prior models. Being a lithium-ion battery, it lasts long, and over-charging does not detract from the battery's recharging functions.

The battery pack can also be attached to the following places – on the down tube, or on the rear carrier. The battery pack can be recharged without being removed from the bicycle when placed on the down tube or rear carrier.

With these two variations, bicycle manufacturers have increased freedom of design, allowing more models to equip the assist system. The PWseries is designed to cater to a variety of bicycle types, from commuters, road bikes, mountain bikes, and small-wheeled bicycles.