What Type of Clutch?

[MolaKule]

This type of clutch has recently been used in some automatic (Step-Shift) transmissions because it cannot slip; I.e. it is either engaged or disengaged.


What is the name of this type of clutch?


This question is open to all.

 

[tundraotto]

Sprag Clutch?

 

[Danno]

Dog clutch

 

[Trav]

"Step Shift" Can refer to anything from older Citroen semi automatics to new knocks offs of that system used by BMW or a old Sturmy Archer 3 spd bicycle gear box.
Probably a Dog clutch as you say its engaged or not no slip.

 

[97prizm]

Centrifugal clutch?

 

[double vanos]

Dog clutch?

 

[ag_ghost]

dual-Clutch aka
twin-clutch

 

[MolaKule]

A Sprague clutch is a "directional clutch" that uses a ball bearing and a cam to create a wedge action for transmitting torque:

https://gfycat.com/ablepitifulannashummingbird-roller-coaster , so that is not the one we seek.

Those who said it was the Dog Clutch is correct and congratulations.

The Dog Clutch is either engaged or disengaged, so there are no frictional surfaces nor any pistons to be actuated by the AT hydraulic fluid.

However, the engagement or disengagement of the Dog Clutch has to be timed correctly because of the geometry, and so shift feel can be different as described by the following article:

Dog Clutch in ZF9 transmission

 

[Overfill]

Mola,

How do formulations between ATs that use Dog clutches differ from those that do not (i.e. Dex VI)? Are there any formulation differences?

 

[MolaKule]

The XXXTE series of ZF AT's contain both conventional wet clutch, clutch packs and Dog Clutches.

The dog clutches in these transmissions have different diameters.

Since we have both wet clutches and dog clutches, we need a bit more AW chemistry with some conventional wet clutch FM chemistry.

Weber State University has an explanation of operation for this Unique and compact transmission/transaxle:

https://www.youtube.com/watch?v=8aChAGYTmZk

Notice in the first video he states that the dog clutches have index indicators on the side surfaces to index the dog clutch teeth. This "indexing" situation has created a number of software updates because customer feedback indicated a shift feel that was deemed unacceptable.

 

[BusyLittleShop]

Another type that qualifies under "cannot slip; I.e. it is either
engaged or disengaged" are seamless gear boxes which sports the
advantage of the input shaft and gears are essentially one unit, with
the gears splined to the shaft and spinning at the same speed at all
times. On the output shaft, all the gears spin freely, but inside each
gear is a set of four pawls that can lock the gear to the shaft to
transmit power. The pawls are pushed into place by pins that are
extended outward from the center of the shaft by a set of rods inside;
using a ratchet effect, two of the pawls lock into place under power,
while two lock into place under deceleration.



Honda's patented 50K seamless shift...