
A torque tube system is a power transmission and braking technology that involves a stationary housing around the
drive shaft, often used in automobiles with a front engine and rear drive. The torque tube consists of a large diameter stationary housing between the transmission and rear end that fully encloses a rotating tubular steel or small-diameter solid drive shaft (known colloquially in the U.S. as a "rope drive") that transmits the power of the engine to a regular or
limited-slip differential
A limited-slip differential (LSD) is a type of differential that allows its two output shafts to rotate at different speeds but limits the maximum difference between the two shafts. Limited-slip differentials are often known by the generic tr ...
. The purpose of a torque tube is to hold the rear end in place during acceleration and braking. Otherwise, the axle housing would suffer axle wrap, such that the front of the differential would lift up excessively during acceleration and sink down during braking. Its use is not as widespread in modern automobiles as is the
Hotchkiss drive
The Hotchkiss drive is a shaft drive form of power transmission. It was the dominant means for front-engine, rear-wheel drive layout cars in the 20th century. The name comes from the French automobile manufacturer Hotchkiss, although other maker ...
, which holds the rear end in place and prevents it from flipping up or down, during acceleration and braking, by anchoring the axle housings to the leaf springs using spring perches.
Construction
The "torque" that is referred to in the name is not that of the driveshaft, along the axis of the car, but that applied by the wheels. The engineering problem that the torque tube solves is how to get the traction forces generated by the wheels to the car frame. The torque moving the wheels and axles in a forward direction is met with an "equal and opposite" reaction of the axle housing and differential, making the differential want to spin in a reverse direction, in the same way that a cyclist "pops a wheely", lifting the bicycle in the air in the opposite direction from the turn of the wheel. The essential problem is how to keep the differential from rotating during acceleration and braking. The torque tube solves that problem by coupling the
differential housing to the
transmission housing and therefore propels the car forward by pushing up on the engine/transmission and then through the engine mounts to the car frame, with the reverse happening during braking. In contrast, the Hotchkiss drive transmits the traction forces to the car frame by using suspension components such as
leaf springs or
trailing arm
A (semi) trailing-arm suspension, sometimes referred to as (semi) trailing-link is a vehicle axle or wheel suspension design in which one or more horizontal arms (or "links"), perpendicular to and forward of the axle, are connecting the axle or ...
s.
A type of
ball and socket joint called a "torque ball" is used at one end of the torque tube to allow relative motion between the axle and transmission due to suspension travel. Later
American Motors
American Motors Corporation (AMC; commonly referred to as American Motors) was an American automobile manufacturing company formed by the merger of Nash-Kelvinator Corporation and Hudson Motor Car Company on May 1, 1954. At the time, it was t ...
Rambler models (1962 through 1966) used a flange and cushion mount in place of the ball and socket. Since the torque tube does not constrain the car's body to the axle in the lateral (side-to-side) direction a
panhard rod is often used for this purpose. The combination of the panhard rod and the torque tube allows the easy implementation of soft coil springs in the rear to give good ride quality, as in Buicks after 1937. Before 1937, Buicks used leaf springs, so the panhard rod was not used, though the torque tube allowed a
cantilever spring suspension, which gives a softer ride than a center-mount axle on the leaf spring, as required by the Hotchkiss setup.
In addition to transmitting traction forces, the torque tube is hollow and contains the rotating
driveshaft
A drive shaft, driveshaft, driving shaft, tailshaft ( Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power and torque and rotation, usually used to conne ...
. Inside the hollow torque ball is the
universal joint
A universal joint (also called a universal coupling or U-joint) is a joint or coupling connecting rigid shafts whose axes are inclined to each other. It is commonly used in shafts that transmit rotary motion. It consists of a pair of hinges ...
of the driveshaft that allows relative motion between the two ends of the driveshaft. In most applications the drive shaft uses a single universal joint which has the disadvantage that it causes speed fluctuations in the driveshaft when the shaft is not straight. The Hotchkiss drive uses two universal joints, which has the effect of canceling the speed fluctuations and gives a constant speed even when the shaft is no longer straight .
V8-powered models of the 1963-1966
AMC Rambler
Rambler is an automobile brand name that was first used by the Thomas B. Jeffery Company between 1900 and 1914.
Charles W. Nash bought Jeffery in 1916, and the name was reintroduced to the automobile marketplace by Nash Motors from 1950 to 1954. ...
used a
double-Cardan constant velocity joint to eliminate driveshaft fluctuations, though six-cylinder and earlier V8 models used only one standard universal joint.
The torque tube design is typically heavier and securely ties the rear end together, thus providing for a rigid rear end and assuring good alignment under all conditions. However, because of the greater unsprung weight of the torque tube and radius rods, there may be a "little hopping around of the rear end when cornering fast or on
washboard roads".
Application
Examples of the torque tube were the American cars of the
Ford brand up through 1948, including over 19,000,000
Model Ts.
Ford used the less expensive transverse springs that could not take forward thrust. For many of those years,
Chevrolet used the torque tube, while
Buick
Buick () is a division of the American automobile manufacturer General Motors (GM). Started by automotive pioneer David Dunbar Buick in 1899, it was among the first American marques of automobiles, and was the company that established General ...
used it starting in 1906 (in the model D). The torque tube also allowed Buick, beginning in 1938, to use coil springs for a softer ride than traditional leaf springs, which can use a
Hotchkiss drive
The Hotchkiss drive is a shaft drive form of power transmission. It was the dominant means for front-engine, rear-wheel drive layout cars in the 20th century. The name comes from the French automobile manufacturer Hotchkiss, although other maker ...
, but coil springs cannot. Buick's use of a torque tube and coil springs became a Buick "engineering trademark", until it was dropped with the 1961 model year full-sized models.
The
Nash 600
The Nash 600 is an automobile that was manufactured by the Nash-Kelvinator Corporation of Kenosha, Wisconsin for the 1941 through 1949 model years, after which the car was renamed the Nash Statesman. The Nash 600 was positioned in the low-priced ...
model adopted torque-tube drive in 1941 without an enclosed joint, but utilized a "horizontal yoke at the front end of the torque tube is supported by rubber biscuits at each side."
After the merger of Nash and Hudson in 1954,
American Motors Corporation
American Motors Corporation (AMC; commonly referred to as American Motors) was an American automobile manufacturing company formed by the merger of Nash-Kelvinator Corporation and Hudson Motor Car Company on May 1, 1954. At the time, it was t ...
(AMC) continued to use the coil spring and torque tube rear suspension design on their large-sized cars (
Rambler Classic
The Rambler Classic is an intermediate sized automobile that was built and sold by American Motors Corporation (AMC) from the 1961 through 1966 model years. The Classic took the place of the Rambler Six and Rambler Rebel V-8 names, which were ...
and
Ambassador
An ambassador is an official envoy, especially a high-ranking diplomat who represents a state and is usually accredited to another sovereign state or to an international organization as the resident representative of their own government or sov ...
) from the 1956 through the 1966 model year. The enclosed driveshaft made for more complicated gear swaps and hampered hot rodders. The discontinued torque-tube drive was replaced by a completely new open driveshaft and four-link axle-location system.
The 1961
Pontiac Tempest
The Pontiac Tempest is an automobile that was produced by Pontiac from 1960 to 1970, and again from 1987 to 1991.
The Tempest was introduced as an entry-level compact in October 1960 at the Paris Auto Show for the 1961 model year. An innovativ ...
was introduced as a new model, featuring an
inline 4
A straight-four engine (also called an inline-four) is a four-cylinder piston engine where cylinders are arranged in a line along a common crankshaft.
The vast majority of automotive four-cylinder engines use a straight-four layout (with the e ...
coupled to a
transaxle
A transaxle is a single mechanical device which combines the functions of an automobile's transmission, axle, and differential into one integrated assembly. It can be produced in both manual and automatic versions.
Engine and drive at the s ...
via a torque tube, giving it a perfect 50-50 front-rear weight balance.
The
Peugeot 403 and
404
404 may refer to:
* 404 (number)
* AD 404
* 404 BC
* HTTP 404, the HTTP error response status for "Not Found"
Cars
* Peugeot 404
* Bristol 404, produced in the 1950s
* Unimog 404
Highways
* A404(M) motorway, in England
* Ontario Highway 40 ...
models used a torque tube. The
Peugeot 504, and
Peugeot 505 estate/station wagons, as well as most export-market sedans also had torque tubes, while domestic and European-market sedan models had a
transaxle
A transaxle is a single mechanical device which combines the functions of an automobile's transmission, axle, and differential into one integrated assembly. It can be produced in both manual and automatic versions.
Engine and drive at the s ...
and individual rear suspension.
The
Chevrolet Chevette (1976-1988) and the similar Pontiac T-1000 used a torque tube and center bearing. This design was unlike any other Chevrolet model "to isolate impacts to the rear wheels, cut down on road noise, and reduce engine vibration ... also allows a reduction in the height of the drive shaft and tunnel."
The continuing limited production of the
Avanti switched to a new chassis in 1986 that utilized a torque tube along with an
independent rear suspension.
The Mercedes SLS has a torque tube, but only to align the transaxle with the engine.
The
Chevrolet Corvette
The Chevrolet Corvette is a two-door, two-passenger luxury sports car manufactured and marketed by Chevrolet since 1953. With eight design generations, noted sequentially from C1 to C8, the Corvette is noted for its performance and distinctive ...
has used a torque tube since the 1996 introduction of the
C5 version in the 1997 model year.
References
{{DEFAULTSORT:Torque Tube
Automotive transmission technologies