Friction drive
Encyclopedia
A friction Drive or friction engine is a type of transmission
that, instead of a chain
and sprockets, uses 2 wheel
s in the transmission to transfer power to the driving wheels. This kind of transmission is often used on scooters
, mainly go-peds, in place of a chain.
An example of this system is in an early Turicum
automobile. The Turicum's friction drive consisted of a flat steel disc coupled directly to the engine. This primary disc subsequently drove a smaller leather
covered wheel oriented normal to its surface. Assuming a constant rotational velocity on the primary wheel, the angular velocity on the disc's surface will increase proportionally to the distance from the center of rotation. Therefore, positioning the smaller wheel at different points along the larger wheel's surface varies the gear ratio
. Furthermore, since there are no limitations beyond the minimum and maximum positions, the gear ratios are infinitely adjustable.
The problem with this type of drive system is that they are not very efficient. Since the output wheel (leather covered wheel) has width, the area of contact is spread across various radii on the primary disc. Consequently, since the angular velocity varies as radius varies, the system must overcome these variances. The compromise is slippage of the leather to metal contact area which creates friction, which in turn converts much of the energy transfer of this system into heat. Heat generation also requires a cooling system to keep the transmission working effectively.
, the Arista
, the Armadale
, the Astra
, the Allvelo
, the Bukh & Gry
, the Crown 12HP Model Two (1905-1906), the Davis Totem
, the Ner-a Car
, the Cartercar
and the Turicum
.
's first three models, the AL, BL and CL were equipped with a friction drive.
Transmission (mechanics)
A machine consists of a power source and a power transmission system, which provides controlled application of the power. Merriam-Webster defines transmission as: an assembly of parts including the speed-changing gears and the propeller shaft by which the power is transmitted from an engine to a...
that, instead of a chain
Chain
A chain is a sequence of connected links.Chain may also refer to:Chain may refer to:* Necklace - a jewelry which is worn around the neck* Mail , a type of armor made of interlocking chain links...
and sprockets, uses 2 wheel
Wheel
A wheel is a device that allows heavy objects to be moved easily through rotating on an axle through its center, facilitating movement or transportation while supporting a load, or performing labor in machines. Common examples found in transport applications. A wheel, together with an axle,...
s in the transmission to transfer power to the driving wheels. This kind of transmission is often used on scooters
Scooter (motorcycle)
A scooter is a motorcycle with step-through frame and a platform for the operator's feet. Elements of scooter design have been present in some of the earliest motorcycles, and motorcycles identifiable as scooters have been made from 1914 or earlier...
, mainly go-peds, in place of a chain.
An example of this system is in an early Turicum
Turicum
Turicum was a Swiss automobile manufactured between 1904 and 1906 in Zurich, 1907 till 1912 in Uster. Turicum is the Latin name of Zurich....
automobile. The Turicum's friction drive consisted of a flat steel disc coupled directly to the engine. This primary disc subsequently drove a smaller leather
Leather
Leather is a durable and flexible material created via the tanning of putrescible animal rawhide and skin, primarily cattlehide. It can be produced through different manufacturing processes, ranging from cottage industry to heavy industry.-Forms:...
covered wheel oriented normal to its surface. Assuming a constant rotational velocity on the primary wheel, the angular velocity on the disc's surface will increase proportionally to the distance from the center of rotation. Therefore, positioning the smaller wheel at different points along the larger wheel's surface varies the gear ratio
Gear ratio
The gear ratio of a gear train is the ratio of the angular velocity of the input gear to the angular velocity of the output gear, also known as the speed ratio of the gear train. The gear ratio can be computed directly from the numbers of teeth of the various gears that engage to form the gear...
. Furthermore, since there are no limitations beyond the minimum and maximum positions, the gear ratios are infinitely adjustable.
The problem with this type of drive system is that they are not very efficient. Since the output wheel (leather covered wheel) has width, the area of contact is spread across various radii on the primary disc. Consequently, since the angular velocity varies as radius varies, the system must overcome these variances. The compromise is slippage of the leather to metal contact area which creates friction, which in turn converts much of the energy transfer of this system into heat. Heat generation also requires a cooling system to keep the transmission working effectively.
In automobiles
Automobiles using this drive system included the Anglo-DaneAnglo-Dane
The Anglo-Dane was a Danish automobile manufactured by H. C. Fredriksen of Copenhagen from 1902 to 1917. Fredriksen began by building bicycles in the 1890s; for these he used British parts - hence the name....
, the Arista
Arista (1912 automobile)
The Arista was a French automobile which took its name from its founder, one P. Arista-Ruffier; the marque was manufactured in Paris from 1912 to 1915. Eight models were introduced in the first year of production...
, the Armadale
Armadale (automobile)
The Armadale was an English automobile manufactured from 1906 to 1907 by Armadale Motors Ltd, Northwood, Middlesex, then Northwood Motor & Engineering Works, also of Northwood....
, the Astra
Astra (1922 automobile)
The Astra was a small French cyclecar made by E Pasquet in Paris with a twin-cylinder two-stroke engine of 496 cc; the automobile, which was manufactured only in 1922, featured independent suspension on all four wheels, as well as friction drive....
, the Allvelo
Allvelo
Allvelo was a company founded by Fritiof Karlström in Landskrona. They mostly made bicycles, but between 1903 and 1907 they assembled and sold CKD cars and trucks under their own name. For instance, they sold Waltham the US Orient Buckboard as Allvelo Orient and Allvelo Pansarmobil Sport and the...
, the Bukh & Gry
Bukh & Gry
The Bukh & Gry was a Danish automobile manufactured in 1904. Its creators, Bukh and Gry, had both worked in the American automotive industry; together they built only one car, manufactured at Horve and shown at the Tivoli Gardens in Copenhagen in 1905. This model had a water-cooled 10/12 hp...
, the Crown 12HP Model Two (1905-1906), the Davis Totem
Davis Totem
The Davis Totem was an American automobile manufactured from 1921 until 1922. As many as ten were built; they boasted friction drive similar to that found in their contemporaries, the Kelsey and the Metz. The cars used four-cylinder Herschell-Spillman engines. The touring car, which seated five,...
, the Ner-a Car
Ner-a Car
The Ner-a-Car was a type of feet forwards motorcycle designed by Carl Neracher in 1918. Around 6,500 Ner-a-Cars are believed to have been produced between 1921 and 1927 in England, and about 10,000 Neracars in the US...
, the Cartercar
Cartercar
The Cartercar was an American automobile manufactured in 1905 in Jackson, Michigan, in 1906 in Detroit, and from 1907 to 1915 in Pontiac, Michigan.-History:...
and the Turicum
Turicum
Turicum was a Swiss automobile manufactured between 1904 and 1906 in Zurich, 1907 till 1912 in Uster. Turicum is the Latin name of Zurich....
.
In locomotives
Plymouth Locomotive WorksPlymouth Locomotive Works
Plymouth Locomotive Works was a US builder of small railroad locomotives. All Plymouth locomotives were built in a plant in Plymouth, Ohio until 1997 when the company was purchased by Ohio Locomotive Crane and production moved to Bucyrus, Ohio in 1999...
's first three models, the AL, BL and CL were equipped with a friction drive.