Abstract:
A drive arrangement comprising a power source driving a First shaft, a second shaft, and at least one double overrunning clutches mechanically connecting the first shaft to the second shaft. 
     The double overrunning clutch is stacked in axial alignment around said first shaft and engage an interior surface of the second shaft such that torque from the first shaft can be selectively transmitted to the second shaft.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     Provisional Application for Patent No. 61/200,199 of Nov. 25, 2008 with the same title “Bi-Directional Overrunning Clutch Assembly” which is hereby incorporated by reference. Applicant claims priority pursuant to 35 U.S.C. Par. 119 (e) (i). 
     Co-pending application Ser. No. 12/583,260 for Hydraulic Hybrid Drive Apparatus filed May 16, 2009. 
    
    
     A portion of the disclosure for this patent document contains material to which a claim for copyright is made. The copyright owner has no objection to the facsimile reproduction of by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but reserves all other copyrights whatsoever. 
     STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a bi-directional overrunning clutch assembly such as would be used for purposes of power transmission, especially in fluid power driven machinery and equipment. 
     2. Background Information 
     Hydraulic systems are popular in applications involving hazardous, dirty, and nasty environments, such as coal mines, quarries, food processing plants, and construction sites. 
     Much effort has been expended in trying to increase the efficiency and performance ranges of hydraulic drives. The experience of co-inventor, George H. Morgan, over the past 35 years, has been that simple mechanisms in convenient packages for bolting between hydraulic components such as hydraulic pumps and motors, greatly simplify and extend the range of applications for hydraulic driven machinery and equipment. 
     This is especially true for brakes, clutches, and brake/clutch combinations. 
     Past industrial surveys have indicated that the field of brakes and clutches is most frustrating for machinery designers. They can&#39;t find what they want and application information is inadequate in many instances. The problem is especially acute for short run equipment and machinery manufacturers. 
     As an example, the development of the AUSCO™ failsafe brake and clutch line featured brakes, brakes with one way clutches, and clutches in convenient configurations that bolted between planetary gear boxes and hydraulic motors, most of which had mounting configurations to the SAE J744 pump mounting standards. With standard convenient configurations, ready to bolt into position, with large factors of safety, the simple approach was very well received by equipment and machinery designers. By having standard, off the shelf configurations, matching what was already out there, marketed through fluid power distributors as an afterthought with the hydraulic motors and pumps, produced in respectable volumes, the approach swept the industry in the 1970s and 1980s. The approach solved a real problem in the application of brakes and clutches for the short line equipment builders. The volume demand permitted economics of scales that led to the acceptance by major manufacturers beyond short run equipment builders. While there is a double over-running clutch available from HILLIARD™, it is not in a package convenient to short run equipment manufacturers. 
     SUMMARY OF THE INVENTION 
     The present invention in the preferred embodiment is a clutch assembly comprising a housing, at least one self engaging bi-directional overrunning clutch, a power input shaft, a power output shaft, shaft supporting bearings, seals, and retaining rings. 
     The housing, in the preferred embodiment of the present invention, comprises a forward male pilot and a rear female pilot, and mounting flanges to simplify installation. The at least one bi-directional over-running clutch fits between the power input and the power output shafts. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1 and 1A  illustrate potential applications of the preferred embodiment of the present invention, a bi-directional overrunning clutch assembly. 
         FIG. 2  illustrates the preferred embodiment of the present invention is a configuration facilitating installation. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIG. 2 , the preferred embodiment of the present invention, a self engaging bi-directional overrunning clutch assembly  1  comprises a housing  2 , at least one self engaging bi-directional overrunning clutch  3 , a power input shaft  6 , a power output shaft  17 , shaft supporting bearings  10 ,  11 ,  13 ,  14 , and  20 , seals  5  and  18 , snap rings  9 ,  14 ,  15 ,  16 , and a spacer  4 . 
     The housing comprises mounting flanges  22  and  23 . 
     In operation, When an input torque is imparted to either of said shafts  6  or  17 , the at least one bi-directional overrunning clutch  3  engages the other of said shafts  6  or  17 , imparting the torque from the either of said shafts  6  or  17  to the other of said shafts  6  or  17 , to drive a load such as a wheel  109  (Ref.  FIG. 1A ) or a wheel  109  through a differential  105  (Ref.  FIG. 1 ). 
     To simplify the explanation, say the said shaft  6  is driving the said shaft  17  through said clutch assembly  1 , which is driving the wheel  109  shown in  FIG. 1A . If the wheel  109  overruns the driving shaft  6 , the said shaft  17  overrun the said shaft  6 , because of the at least one self engaging bi-directional overrunning clutch  3 . In the arrangement shown in  FIG. 2  there are two clutches  3  mechanically acting in parallel, that is to say each clutch  3  carries half the load and in overrunning both clutches overrun. 
     This provides significant advantage over simply making a bigger clutch as a bigger clutch would take up more space causing the shaft  6  to be larger in diameter which in turn would cause the housing  2  to be larger in diameter which is very undesirable in many applications. Using the concept it would be possible to arrange 3 or 4 clutches in parallel to carry higher loads. 
     In  FIG. 1 , a hydraulic motor  107  is driving through said clutch assembly  1  into the a differential  105 , to turn the wheels  109 , while a transmission  103  is in neutral. When an operator of a vehicle drive with an internal combustion engine  102  serving as the power source, the transmission  103 , a driveline  104 , the differential  105 , axles  108 , and wheels  109  wants to go faster, such as after start up with the hydraulic motor  107 , the operator of the vehicle drive can engage the transmission  103  and drive the driveline  104  which drives through the differential  105  which drives the axles  108  which drive the wheels  109  from the engine  102 , through the transmission  103 , through the driveline  104 , through the differential  105 , through the axles  108 , overrunning the hydraulic motor  107  because of the self engaging bi-directional overrunning clutches  3  within the clutch assembly  1 . This is a much simpler approach than using a multiple disc or jaw clutch or cone clutch with all the problems of engagement and disengagement. 
     In  FIG. 1A , in a multiple wheel vehicle, driving the vehicle faster with other wheels is greatly simplified with the self engaging bi-directional overrunning clutch assembly  1  ((Ref.  FIG. 1 ). This facilitates multiple speed arrangements for vehicle designers, such as, but not restricted to construction equipment, where sometimes extra torque is required in a low speed mode. 
     In the preferred embodiment of the present invention, the at least one self engaging bi-directional overrunning clutch  3  is a Hilliard™ self engaging bi-directional overrunning clutch such as is known in the snowmobile and ATV trade. 
     As HILLIARD™ has limited sizes available, having said shafts  6  and  17  properly sized to allow multiple said clutches  3  to be inserted between said shafts  6  and  17 , the torque rating of said clutch assembly  1  can be increased, with minimal effect on configuration profile.  FIG. 1  illustrates a hydraulic pump  110 , with hydraulic lines  112 , which are in fluid communication with a hydraulic motor  107  attached to said clutch assembly  1  which is connected to a differential  105  which is connected to a driveshaft  104  and axles  10 , said axles  118  driving wheels  109 , said driveshaft  104  attached to a transmission  103 , attached to an engine  102 . The hydraulic pump  110  comprises a solenoid actuated clutch engageable pulley  111  driven by a belt drive off the engine  102 . 
     The differential  105 , as shown in  FIG. 1 , has two inputs, one from the drive line  104  and one from the hydraulic motor  107  through the clutch assembly  1 . This permits two inline torque inputs into the differential  105  which is very simple design approach as compared to existing cumbersome approaches. Extra pieces and extra connections are very unacceptable in the automotive design world. 
     For hydraulic driving of the wheels at low speed, the transmission  103  is in neutral, the solenoid actuated clutch engageable pulley is engaged, engaging the pump  110  which pumps oil to the motor  107  to drive through said clutch assembly  1  with a mounting housing  2 , engaging said at least one clutch  3  (Ref.  FIG. 2 ), which drives through the differential  105 , which drives the axles  108 , which drives the wheels  109 . 
     When a higher speed is desired, the transmission  103  is engaged, the hydraulic pump  110  disengaged, and the drive shaft  104  drives through the differential  105  at a higher speed than the hydraulic motor  107 , and the power output shaft  107   FIG. 2 ) overruns the power input shaft  6 , thanks to said at least one clutch  3 . This greatly simplifies clutch engaging arrangements as compared to cone clutches, multiple disc clutches, or other types of clutches that require force inputs for actuation or release. 
     In the preferred embodiment the differential  105  is of the type with a ring gear and two pinion gears which is common to the trade. 
     In the preferred embodiment of the present invention, the pump clutch  111  is a solenoid operated belt and pulley driven electric clutch such as is used in automotive air conditioning systems. Scherer Fluid Power, of Troy, Mich. applied such a clutch to a hydraulic pump some 25 or 30 years ago. The pump clutch  111  is shown with the pump  110  with hydraulic lines  112  which are in fluid communication with the hydraulic motor  107 . 
     In the preferred embodiment of the present invention, the hydraulic motor  107  is a ROLLER STATOR™ HB series hydraulic motor manufactured by White Hydraulics of Hopkinsville, Ky. 
     In the preferred embodiment of the present invention, the clutch  3  is a self engaging bi-directional overrunning clutch such as is manufactured by the motion control division of the Hilliard Corporation of Elmira, N.Y. The clutch  3  as is manufactured by the Hilliard Corporation comprises modified SPRAG™ type elements that not only engage upon power input, from either direction but permits a driven load to overrun the power input. 
     In operation, when smooth operation of a vehicle drive (not shown) at low speeds is desired, 
     the engine  102  power is diverted from the drive line  104  by having the transmission  103  in neutral, and using the hydraulic pump  110 , through the belt drive  113  and the pump clutch  111 . Hydraulic fluid is pumped from the hydraulic pump  110  to drive the hydraulic motor  107 , mounted on the clutch assembly  1  which is mounted on the differential  109 , said hydraulic motor  107  driving the axles  108  through the clutch assembly  1  which is engaged by the activation of the internal modified SPRAG type elements upon receiving an input motion from the hydraulic motor  107 . The axles  108  drive the wheels  109 . The engine  102  is operated in a speed range where the engine  102  operation is smooth, and efficient, while the speed of the driven wheels  109  of the vehicle (not shown) can be controlled by various means such as a variable speed axial piston pump  110 , a variable speed hydraulic motor  107 , or, with proper sizing, a fixed displacement pump  110  and a fixed displacement hydraulic motor  107 , such as the previously mentioned ROLLER STATOR HB hydraulic motor  107 , and a variable engine  102  speed. 
     Danfoss Sauer, with plants in Denmark, Germany, and the United States, manufactures a range of axial piston hydraulic pumps with electro/hydraulic controls that would be quite suitable for this application. 
     When a given speed is reached where said engine  102  can operate the vehicle in a conventional manner, the transmission  103  is engaged, the hydraulic pump  110  is declutched. The hydraulic motor  107  is not engaged because of the overrunning feature of said at least one said clutch  3  of said clutch assembly  1 . 
     In the preferred embodiment of the present invention, said engine  102  is a gasoline engine which is using fuel compression ignition technology from diesel engines to improve engine performance. Currently, this is known as homogeneous charge compression ignition technology. 
     By setting said engine  102  in the conventional manner to drive a vehicle at optimum transit speeds for fuel economy, and using the hydraulic drive arrangements at slow speeds, such as initial start up speeds to reach transit speeds, the limitations inherent in current HCCI engines are considerably alleviated. 
     Combining a hydraulic drive apparatus with a homogeneous charge compression ignition technology prime mover engine  102  alleviates the problem of rough operation of a vehicle with a homogeneous charge compression ignition technology prime mover engine  102  operating at low speeds. 
     An alternate preferred embodiment is the conversion of front wheel drive vehicles to four wheel drive vehicles by using the engine  102  to drive the hydraulic pump  110  to drive two hydraulic motors  107 , each of said hydraulic motors  107  driving through a respective clutch assembly  1  to drive it&#39;s respective rear wheel  109 . This is a solution for converting front wheel drive vehicles to four wheel drives, a problem that has perplexed vehicle designers to the present day (Ref.  FIG. 1A ). The self engaging bi-direction overrunning clutch  3  permits forward and reverse operation, without external means of engagement. 
     A second alternative embodiment would be an auxiliary vehicle drive means comprising the engine  102  driving the pump  110  supplying fluid to each of two hydraulic motors  107  through its respective clutch assembly  1  into each of the two front wheels  109  of a rear wheels  109  driven vehicle-or into the rear wheels  109  of a front wheel  109  driven vehicle. This is a means of converting two rear wheel driven vehicles such as pickup trucks used as service auxiliary vehicles in surface mining operations to four wheel drives, providing the higher torque required for driving up mine access slopes than is standard with conventional four wheel drive vehicles. Ref  FIG. 1A  illustrating a hydraulic motor  107  into said clutch assembly  1  into the wheel  109 . 
     As an example, with a differential  105  with a 3.5/1 input/output ratio, and a 210 foot pound Hilliard self engaging bi-directional double overrunning clutch  3  tied into the drive line  4  through the differential  105 , with a 6.5 cubic inch White ROLLER STATOR™ HB series motor  107 , with the hydraulic pump  110  producing 4.4 gallons per minute (gpm) at 3,000 psi, with a wheel  9  rolling radius of 13 inches, the tractive effort of each of the wheels  9  at 3,000 psi would be approximately 680 pounds. The 4.5 gpm would result in approximately 10 miles per hour vehicle speed. This figure assumes an 85% mechanical efficiency with a 90% volumetric efficiency of the ROLLER STATOR hydraulic motor  107  serving as the hydraulic motor  107 , and a 90% volumetric efficiency for the hydraulic pump  110 . For a hydraulic pump or motor, the volumetric efficiency represents the usable output of fluid compared to the fluid input. The difference is the internal leakage required for lubrication of internal parts of the hydraulic pump or motor. The internal leakage is a function of pressure differential across the hydraulic pump or motor. 
     In co-applicant Morgan&#39;s experience, spanning some forty years in the field of hydraulics comprising product design, circuit design, and sales and marketing experience, the combination of an axial piston pump  110  and a White Hydraulics model HB motor  109 , in vehicle drives, precludes the requirement of a hydraulic oil cooler. 
     Using multiple said clutches  3 , multiples of the above calculated torques can be obtained with off the shelf clutches  3 , thereby avoiding tooling costs for special configuration, such as larger diameters. 
     The White Hydraulics ROLLER STATOR™ HB series White motor has very smooth operation at unusually low revolutions. Applicant witnessed a HB series motor (in the 24 cubic inch displacement, as memory serves, some 20 years ago) tested at one sixth of a revolution per minute, with no visible clocking or output shaft ripple. It was used on hydraulic wheel chair drives because of this characteristic. In the preferred embodiment of this invention, the operating speed is from zero to approximately 132 revolutions per minute. With proper fluid selection the speed range is approximately triple that. However, the intent is to operate a vehicle with hydraulics until the vehicle speed is such the said engine  2  can smoothly operate the vehicle. 
     Although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. 
     For example, the HILLIARD double overrunning clutch  3  is the preferred embodiment, as is the pulley driven electric actuated clutch. Weight is an important consideration in vehicle design. However, as obvious to anyone skilled in the art, there are almost countless varieties of clutches that can be made to work, albeit perhaps with weight and complexity disadvantages. 
     Also, there are other ways to tie in the said clutch assembly  1  and the hydraulic motor  107  into the driveline  104 . Adding a power take off gearing arrangement would be an off highway type solution. However, this involves added weight, additional gears with resultant slight decrease in operating efficiencies, and possible loss of smoothest operation potential. 
     Also, the hydraulic pump  110  and pump clutch  111  can be Connected to the engine in a variety of ways, by the automobile manufacture&#39;s engineers, such as, but not restricted to, off the crankshaft at the front of the engine, off an accessory drive gearing arrangement, or a chain accessory drive. Space limitations, weight, reliability, and cost are among the factors involved. 
     In front wheel drives, the drive shaft  104  and the differential  105  functions, as well as the transmission  103  functions, are incorporated adjacent, if not within, the engine  102 . So, the said clutch assembly  1  and the motor  107  could be tied into the differential  105  in the engine  102 /transmission  103  region of the vehicle, as opposed to the rear of the vehicle as indicated in  FIG. 1 . 
     While  FIG. 1  illustrate a differential  105  applied as a rear end differential  105 , the differential  105  could be near the front of a front wheel drive vehicle, incorporated within a different type housing as opposed to what is represented in  FIG. 1 . 
     While the input power shaft  6  is shown as an internally splined shaft, and the output power shaft  1  is shown as an externally splined shaft, as obvious to anyone skilled in the art, either of the shafts  6  or  17  could be internally or externally splined. 
     The term fluid is intended to cover any fluid suitable for serving its intended purpose in the preferred embodiment of the invention described. There are many different types of fluids currently used or being developed for hydraulic drives, such as, but not restricted to, hydraulic oils, engine oils, synthetic oils, vegetable base oils, even water with and without additives. 
     For enablement purposes, MOBIL 1 synthetic oil with a 10W30 viscosity should serve well. The temperature rating is in the order of 400 degrees F. as opposed to most hydraulic oils designed for 120 degree F. system temperatures. This oil worked well for an application of a hydraulic drives designed by co-applicant Morgan in a region where the ambient temperatures reach 165 degrees F. in the summer. 
     It will be obvious to those skilled in the art that modifications may be made to the embodiments described above without departing from the scope of the present invention. Thus the scope of the invention should be determined by the appended claims in the formal application and their legal equivalents, rather than by the examples given.