Machine element or mechanism – Gearing – Plural power paths to and/or from gearing
Patent
1989-01-19
1991-10-08
Wright, Dirk
Machine element or mechanism
Gearing
Plural power paths to and/or from gearing
180247, F16H 3706
Patent
active
050543350
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to transfer units for four-wheel vehicles and particularly to transfer units which enable four-wheel drive vehicles to be shifted between two-wheel drive and four-wheel drive, and low-gear and high-gear.
Four-wheel drive vehicles are highly desirable for off-road travel over rough terrain. However two-wheel drive vehicles are more desirable on normal hard, improved road surfaces. Therefore to satisfy the needs of the operator who drives on a variety of surfaces, vehicles have been produced that are capable of shifting between two-wheel drive and four-wheel drive. Traditionally, these types of vehicles could only be shifted between two-wheel drive and four-wheel drive when the vehicle was at a halt.
Recently, vehicles capable of shifting between two-wheel drive and four-wheel drive have been produced having transfer units that synchronize their front and rear output shafts before the actual shifting takes place. An example of such a transfer unit can be found in U.S. Pat. No. 4,555,846 to Cochran et al. The synchronizing apparatus in Cochran, however, is hard to repair and requires a plurality of parts that tend to wear out over time.
The capability to shift between low-gear and high-gear is also very desirable. This is especially so for four-wheel drive vehicles, which often encounter terrain that requires the use of low-gear at one point and high-gear at another point. In prior art vehicles having the capability to shift between low-gear and high-gear, such shifting could only be accomplished when the vehicle was at a halt. Stopping the vehicle in order to perform such a shift between low-gear and high-gear has proved to be very inconvenient, especially for the off-road racing enthusiast.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an easily repairable, efficient and economical apparatus for synchronizing the front and rear output shafts of a transfer unit, such that a vehicle in which such transfer unit is installed can shift between two-wheel drive and four-wheel drive while the vehicle is moving.
An additional object of the present invention is to provide an apparatus for synchronizing the rear output shaft and the high gear of a transfer unit, such that a vehicle in which such a transfer unit is installed can smoothly and efficiently shift between low-gear and high-gear while the vehicle is moving.
Generally, the present invention includes a transfer unit having an input shaft, a rear output shaft, a front output shaft, a low-gear/high gear section, and a two-wheel drive/four wheel drive section. The low-gear/high gear section has low and high range power transfer gears which are selectively coupled to the rear output shaft. When the transfer unit is shifted between low-gear and high-gear, the rear output shaft is synchronized with the high range power transfer gear before the high range power transfer gear is actually coupled to the rear output shaft.
The two-wheel drive/four-wheel drive section of the transfer unit has a power transfer gear coupled to the front output shaft and a synchronizer ring coupled to the rear output shaft. The power transfer gear has a beveled portion. When the transfer unit is shifted between two-wheel drive and four-wheel drive, the synchronizer ring engages the beveled portion of the power transfer gear to synchronize the front and rear output shafts before the front and rear output shafts are actually coupled.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of components of a four-wheel vehicle including a transfer unit of the present invention.
FIG. 2 is a cross sectional view of a preferred embodiment the transfer unit as shown in FIG. 1.
FIG. 3 is a cross sectional view of the transfer unit of FIG. 2 as taken on line 3--3.
FIGS. 4a-d are cross sectional views of the low-gear/high gear section of a preferred embodiment of the transfer unit as the vehicle is shifted from low-gear to high-gear.
FIGS. 5a-c are cross sectional views of the two-wheel drive/four-wheel drive sectio
REFERENCES:
patent: 2220463 (1940-11-01), Sinclair
patent: 2385231 (1945-09-01), Peterson et al.
patent: 2397587 (1946-04-01), Armantrout
patent: 3095758 (1963-07-01), Bixby
patent: 3788164 (1974-01-01), Ojima
patent: 4103753 (1978-08-01), Holdeman
patent: 4188838 (1980-02-01), Nakao et al.
patent: 4233857 (1980-11-01), Quick
patent: 4270409 (1981-06-01), Glaze et al.
patent: 4292860 (1981-10-01), Kako et al.
patent: 4305309 (1981-12-01), Ookubo et al.
patent: 4314627 (1982-02-01), Nozawa
patent: 4324152 (1982-04-01), Oshima et al.
patent: 4344335 (1982-08-01), Kawai
patent: 4441379 (1984-04-01), Malkowski et al.
patent: 4462271 (1984-07-01), Stieg
patent: 4559846 (1985-12-01), Cochran et al.
patent: 4605084 (1986-08-01), Haynes et al.
patent: 4745825 (1988-05-01), Yamamoto
patent: 4781266 (1988-11-01), Hoffa et al.
patent: 4782721 (1988-11-01), Dick
patent: 4838121 (1989-06-01), Takeshita et al.
American Motor Corp. publication, Transfer Case 207, pp. 8 and 9 (Mar. 1986).
Subaru Service Manual, Haynes publication 681, 1980-1988, pages attached.
"A Transfer Case That's Out of This World", Four Wheeler Magazine, Feb. 1983, pp. 47-49.
Toyota Repair Manual, vol. 2, Jan. 1989, pp. TF-41, 42 and 58.
LandOfFree
System for shifting four-wheel vehicles does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System for shifting four-wheel vehicles, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System for shifting four-wheel vehicles will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-250169