192 clutches and power-stop control – Clutches – Automatic
Patent
1997-09-15
2000-10-10
Lorence, Richard M.
192 clutches and power-stop control
Clutches
Automatic
F16D 41064
Patent
active
061291897
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to the application of one-way clutches to automotive accessory drives in general, but more specifically to serpentine "flat belt" drives with belt tensioners that are particularly suited for use of a high indexing rate, over-running clutch. It further relates to spiral type one-way clutches of an improved, high indexing rate design.
DESCRIPTION OF THE PRIOR ART
Accessory drive pulleys on internal combustion engines generally incorporate a belt shive and a hub section for attachment to either an engine crankshaft extension or to a driven spindle of an accessory. As such, the accessories are subject to both the low speed oscillations of the engine and to any sudden engine decelerations as up-shifts of the vehicle transmission takes place. When a sudden deceleration of the engine occurs, the alternator and other accessories resist slowing down due to their rotational inertia. This produces, on occasion, a loud "squeal" from the belt-pulley interface. Apart from stress on the belt, this effect is disconcerting to drivers. The remedy in the past has been to raise the tension in the belt, at the cost of increased belt wear.
A further reason why accessory belts are commonly operated at high tension levels is that the rotational output of the crankshaft spindle of an internal combustion engine inherently operates with pulsations or oscillations in its rotational velocity. The consequence for the belt is that its tension level fluctuates above and below a base level. To ensure proper engagement of the belt to the accessory pulley(s), the belt tension is raised above the level at which the tension variations may cause slippage. Thus the presence of an oscillatory component in the belt drive exposes conventional belt systems to an increased stress.
A need exists to provide a means by which the coupling of such oscillations to accessories is reduced or minimized.
A need also exists for an arrangement which will reduce or eliminate the anxiety-causing "belt squeal" that arises from sudden down shifts in engine speed.
It is a premise and object of the invention hereafter described that such need may be addressed by the use of a one-way clutch positioned in the rotary linkages between the main engine crank shaft and the various accessories being driven therefrom. Preferably, such clutch should be of a high indexing rate design in order to best address the problem of belt tension oscillations.
A high indexing rate type of one-way clutch incorporated in the hub of an accessory drive pulley will achieve two results. First, it will isolate the driven components from the slow-speed, high frequency torsional oscillations of the engine, and secondly, it will allow the driven components of the system to disengage from the engine continuum as deceleration takes place during an up-shift of the transmission.
A particular advantage of using these over-running pulleys in an accessory drive system is that by suppressing belt vibration during slow speed engine operation, the need to tighten the belt to a high tension level is reduced. Even if belt tension is not reduced, "belt squeal" arising from belt slippage during rapid decelerations of the engine is eliminated by introducing a one-way clutch into the couplings of an accessory drive system.
One design for a one-way clutch that will serve in this role is preferably provided by a spiral type one-way clutch with features that enhance both its' indexing capability and its' ability to free-wheel under high radial loadings. An object of this invention is, therefore, to provide such a clutch.
Early references to spiral clutch designs include U.S. Pat. No. 2,785,782 and U.S. Pat. No. 3,021,925 and United Kingdom patent GB-A-255943. A more recent form of one-way clutch from the same inventor as for the present invention that provides an improved indexing rate capacity is that described in the following patents: form a spiral channel for roller bearings. The spacing between the spiralled sidewalls of this channel is substantially const
REFERENCES:
patent: 1618915 (1927-02-01), Constantinesco
patent: 4341294 (1982-07-01), Kerr
patent: 4725259 (1988-02-01), Miyata
patent: 5638931 (1997-06-01), Kerr
French David J.
Ker-Train Holdings Ltd.
Lorence Richard M.
LandOfFree
Spiral type one-way clutch does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Spiral type one-way clutch, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spiral type one-way clutch will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2250266