Lock-up Collar and Electromagnetic Clutch

[jvan1947]

Hi, I hope that someone can explain how the EMC and Lock-up collar work to bring the mass of the forward propeller shaft, Crown wheel, Ujoints, drive and driven sprockets and chain up to speed without stretching the chain?
Note I have an ESOTF transfer case (not TOD, not AWD) so I only have 2WH, 4WH and 4WL with CADS for the front axle engagement.
I drive a Hyundai Terracan 2.9L CRDi diesel. For all intents and purposes the TOD version of this car has an almost identical transfer case to the Ford's BW4405 Control Trac (so close in fact that the parts diagrams are identical, including the transfer case shape and ribbings).
I do understand the workings of the TOD version , but the workings of the ESOTF lock up mechanism without the Viscous Coupling is not described anywhere in detail. At least I cannot find it.

NB I do not have any trouble with the system. I just want to know how it works. I have asked Hyundai and Borg Warner but have not recieved replies.

The transfer case in the Hyundai is also used in the Kia and is a BW44-24.

The reason I am asking on this forum is because whenever I put in a search argument on the internet this forum crops up.

Cheers John

 

[gijoecam]

There are several different versions of the 44-05 transfer case. Unfortunately, I cannot tell you how (if?) yours differs from the ones on the Explorer.

Assuming it's functionally the same as the Explorer's, it's going to operate the exact same way it does on the 95-96 Explorers.

In 2wd, the electromagnetic clutch doesn't do anything. Due to the shearing of the fluid between the friction discs of the clutch, it's normal for the front driveshaft to turn, although it's not transmitting any useful power. With the center axle disconnect 'broken', the front differential carrier could, in theory, be stationary (while the spider gears inside the diff would be turning).

When you shift to 4high, the system would engage the electromagnetic clutch in the transfer case, which would quickly accelerate the front driveshaft and differential up to the vehicle's speed. Once both the front and rear drivetrains are spinning the same speed, the left and right front drive axle components will also be turning the same speeds, allowing the center axle disconnect to lock the front axle components together.

For 4low, the same conditions as 4high occur with regards to case and CAD lockup, but the transfer case shift motor engages the low range planetary gear set as well, for added torque.

Does that help?

A few years ago, I had some technical questions about the case. I sent an e-mail to the customer support address listed on the Borg-Warner web site, and had a response within a day or two. It might be worth a call or e-mail to them for further clarification.

Now, it's also possible that the non-TOD case is entirely different, using a traditional electromagnetic clutch to synch the driveline speeds, followed by a lockup collar locking the front and rear outputs together... I really couldn't tell you as I know nothing whatsoever about Hyundais, other than the fact that they have metric fuel lines on some of the older Accents. Sorry.

 

[jvan1947]

Thank You Gijoecam for your reply.

I'm sorry if I did not explain myself correctly. I am only interested in finding out how the manual transfer case works with Electronic Shift on The Fly.
I enclose 2 pics . One is for the BW1345-1350 with electric shift motor as used in the Ford and the Identical picture taken from my Hyundai manual.

Note the Electric Shift Insert Above
and

These pictures clearly show that my Hyundai SUV uses an identical transfer case as the Ford with ESOTF

So I would be very grateful if someone can explain how the 2W-4W lockup in the Ford assembly works. Are there any places where "slip" occurs before the shaft is up to speed. Is there something not shown (eg has the clutch some inbuilt viscous coupling??? )

Before 4W mode is locked the forward propeller shaft is not turning and the Cads have disconnected the Front Right Axle.

Cheers John

 

[gijoecam]

OK, we're not dealing with a Borg-Warner 44-05, we're dealing with a 13-54... Two completely different transfer cases with two completely different operating characteristics. The 13-54 was used in the first-generation (1991-1994) Explorers, and was also used on the Rangers from around 1991 to 2000. (Don't quote me on those years for the Ranger) Regardless, it's NOT the same as a 44-05. Not in any way.

For the electronic shift Rangers, here's the description of the operation from the service manual (obviously the part about the hubs doesn't apply to your vehicle):

Section 07-07A: Transfer Case, 4x4 System, Service 1995 Aerostar/Ranger/Explorer Workshop Manual

DESCRIPTION AND OPERATION

--------------------------------------------------------------------------------

Electronic Shift Operation, Ranger
The transfer case (7A195) is equipped with a magnetic clutch, similar to an air conditioning compressor clutch, which is located inside the transfer case adjacent to the lockup sleeve. The clutch is used to spin up the front drive system from zero to vehicle speed in milliseconds. This spin-up allows the shift between 2H and 4H to be made at vehicle speeds listed in the vehicle owner's guide. The spin-up engages the front lock hubs. When the transfer case rear and front output shaft reach synchronous speed, the spring-loaded shift collar mechanically engages the mainshaft lockup hub to the chain-drive sprocket and the magnetic clutch is then deactivated. Shifts between 4H and 4L can only occur with the transmission safety switches closed. The vehicle's speed must also be within specified limits as determined by the Generic Electronic Module (GEM).

The electronic shift control system consists of a rotary switch control system, a GEM, an electric shift transfer case shift motor (7G360) with an integral shift position sensor, a clutch pedal position switch or transmission range sensor, and a brake signal input switch.

There is a control switch located on the instrument panel for fingertip shift control.


Switch Control System

When the switch on the instrument panel is turned, there is a one second delay, then the electronic control module verifies the transfer case positions (2H, 4H or 4L). Next, the GEM looks at the shift position sensor and the transmission range sensor or clutch pedal position switch (depending on transmission type) and brake pedal switch. If all conditions are correct to allow the desired shift, the electronic control module will tell the electric shift transfer case shift motor to execute the shift. After the shift has been made and the electric shift transfer case shift motor is off, the control module again looks at the shift position sensor to make sure the proper shift has been accomplished. Finally, the dash indicator light on the control panel will be illuminated by a signal from the GEM indicating the desired shift has been completed.

In the manual shift on the fly 13-54 case, I *believe* that the friction of the lockup collar on the front sprocket is what spins the front driveline up to speed, but don't quote me on that either. My knowledge of the 13-54 is very limited.

-Joe

 

[jvan1947]

Hi, GIJOECAM , Thanks for that answer, I now think the answer lies in this statement

Electronic Shift Operation, Ranger
The transfer case (7A195) is equipped with a magnetic clutch, similar to an air conditioning compressor clutch, which is located inside the transfer case adjacent to the lockup sleeve. The clutch is used to spin up the front drive system from zero to vehicle speed in milliseconds.

Yes the lockup up assembly (2H-4H) could work like an AC clutch. After spending more time with the available documentation, it appears that the Electromagnet is pulsed on for about 11 seconds. During this time the forward prop shaft and attached mass is spun up to speed (milliseconds) , the shift fork will latch/position the lock-up collar so that the drive sprocket is driven by the lockup collar which is now splined to the drive shaft.

I think that this is probably very close to how ESOTF 2H-4H works..

During this 11 seconds the Cads will engage the Front Right wheel axle (providing the splines line up). This may not be the case if the vehicle is stationary (bogged).

Joe , thank you for your input.

Have a look at http://forum.australia4wd.com/ and in particular the Terracan Forum and our picture gallery.

Cheers John