DRIVE SYSTEM WITH FREEWHEEL CLUTCH

Abstract: The invention relates to a drive system comprising at least one drive source (P) delivering its power by means of a driving, rotation-and-torque transmitting element (T), at least one speed variator (V) and at least one driven, rotation-and-torque receiving element (R), wherein, according to the invention, for distributing power originating from one drive source (P1) over several driven elements (R1, R2) and/or for combining power originating from several drive sources (P1-P4) on a single driven element (R), the or each speed variator (V) is designed as an infinitely variable, slipless freewheel clutch (V).

Description: Title: DRIVE SYSTEM WITH FREEWHEEL CLUTCH This invention relates to a drive system comprising at least one drive source delivering its power by means of a driving, rotation-and-torque transmitting element, at least one speed variator and at least one driven, rotation-and- torque receiving element. Such a device is known for instance as a drive of a passenger car in which the coupling between the wheels and th drive source is formed inter alia by a continuously variable transmission. In general, when, via a speed variator, a driving, rotation-and-torque transmitting element, such as a drive shaft of a drive source, is to be coupled to a driven, rotation-and-torque receiving element, such as a central output shaft, this necessitates the provision of fluid clutches, slip clutches, gearboxes, freewheel clutches and th like so as to tune the speed of the driving element to the speed of the driven element before a coupling is effected. Apart from the fact that power is lost in these parts as a result of heat development and friction, it is impossible, in the absence of these parts, for the speed of the driven element to be regulated steplessly from zero revolutions per second to a maximum value, nor can the driving element be varied from zero rotations per second. One object of the invention is to provide a drive system in which the speed of the driving element is independent of the speed of the driven element and the speed of the driven element can be varied from zero revolutions per second to a maximum value, independently of the speed of the driving element. These conditions must apply throughout the entire control range of the drive system, i.e., from zero speed to a maximum value. A further object of the invention is to provid a drive system in which all driving elements are at all times dynamically coupled to all driven elements, i.e., a drive system without friction, fluid or similar conventional in/out clutches. To that end, the drive system of the type described in the opening paragraph hereof is characterized according to the invention in that, for distributing power originating from one drive source over several driven elements and/or for combining power originating from several drive sources on a driven, rotation-and-torque receiving, single element, the or each speed variator is designed as an infinitely variable, slipless freewheel clutch having an input and an output shaft, the input shaft being provided with at least one pair of eccentric discs whose eccentricity can be varied, also during operation, from a neutral position of zero eccentricity to a maximum value by means of a control device incorporated in the input shaft, the eccentricity of the respective discs being mutually opposite, while a plurality of circumferential units are arranged on a pitch circle whose centre coincides with the centreline of the input shaft and which is located in, or in the vicinity of, a plane in which the eccentric discs can oscillate during operation, these circumferential units each comprising a crank arm which can be driven for oscillation by one of the eccentric discs, the crank arms of the respective circumferential units each being dynamically connected to the output shaft via at least one unidirectional drive system, consisting of a freewheel system, via respective intermediate shafts and a transmission with a fixed transmission ratio. Such a drive system can serve for distributing power originating from one drive source over several driven, rotation-and-torque receiving elements and can also serve for combining power originating from several drive sources on a single, rotation-and-torque receiving, driven element. All this can be effected without necessitating the incorporation of additional fluid or friction clutches, gearboxes or similar additional sources of friction into the drive system. Moreover, the operation of such an infinitely variable, slipless freewheel clutch is not based on friction but on positive engagement between freewheel clutches, gears and similar elements. Accordingly, in the infinitely variable, slipless freewheel clutches of the drive system, too, hardly any power will be lost in the form of heat as a result of friction. In addition, such an infinitely variable, slipless freewheel clutch has the advantage that it is practically noiseless. Further, a drive system that is fitted with such infinitely variable, slipless freewheel clutches has the advantage that when the speed of the output shaft of such a freewheel clutch is higher than the speed that is imposed on the output shaft by the input shaft of the freewheel clutch, for instance because the output shaft of the infinitely variable, slipless freewheel clutch is being caused to rotate by the driven, rotation-and-torque receiving element connecte thereto, such motive force being exerted on this output shaft will not be transmitted by the freewheel to the input shaft of the freewheel clutch. This prevents the drive source connecte to the input shaft from being driven by any motive force exerted on the output shaft of the freewheel clutch. In accordance with a further elaboration of the invention, for distributing power originating from one drive source over a plurality of driven elements, the driving element can be dynamically connected to at least two infinitely variable, slipless freewheel clutches whose output shafts are each directly or dynamically connected to one of the driven, rotation-and-torque receiving elements, with speeds of the driven elements being controllable independently of each other. Such an application can for instance be used when several rotation-and-torque receiving, driven elements take their power from a single drive source, it being required tha the speed of the driven elements be infinitely variable without large quantities of power being lost in the process. Heretofore, such a distribution of power has only been possible at the expense of relatively large power losses in clutches and gearboxes or in hydraulic motors . With the distribution of power according to the present proposal, the speed of one of the driven, power receiving elements can be reduced to zero, while the other driven, power receiving elements can be controlled as desired. The possibilities for such a drive system are particularly advantageous, for instance in tractors, where several power receiving elements take their power from a single motor shaft, or in the drive of a tank, where the speeds of the track can be controlled completely independently of each other without interposition of gearboxes . For combining power originating from several drive sources on a driven, rotation-and-torque receiving, single element, it is possible, in accordance with an alternative further elaboration of the drive system, to connect a plurality of infinitely variable, slipless freewheel clutches in parallel, the input shafts of the freewheel clutches each being connected to a rotation-and-torque transmitting, driving element of one of the drive sources, and the freewheel clutches being controllable in such a way that the speeds of the output shafts thereof, which are each dynamically connected to the driven, rotation-and-torque receiving, single element, are tuned to the desired speed of this driven element. Such a drive system makes it possible for one of the driving, rotation-and-torque transmitting elements, which are connected to the driven, rotation-and-torque receiving, single element via infinitely variable, slipless freewheel clutches, to be coupled at a later stage. Thus, a power receiving element that is already being driven for rotation can be supplied with additional power by gradually coupling the driving element that is dynamically connected to the driven element via the infinitely variable, slipless freewheel clutch. If one of the driving, power transmitting elements is stationary, the output shaft of the infinitely variable, slipless freewheel clutch connected thereto rotates freely and in that case the input shaft of this freewheel clutch is stationary. The power that is thus lost in the freewheel clutch is minimal. It is further possible to have the driven single element driven successively by one of the respective driving elements, as desired. Such a use of the drive system makes it possible, for instance, to use the several drive sources for different power ranges . A drive system of such design can for instance be used advantageously in marine propeller drives, where, according to a further elaboration of the invention, the driv sources are marine turbines or marine motors, while the driving, rotation-and-torque transmitting elements are output shafts of the marine turbines or marine motors and the driven, rotation-and-torque receiving single element is a marine propeller shaft. In the current marine propeller drives with several drive sources, use is made of so-called SSS clutches which can couple optimally only in limited, fixed speed ranges, inasmuc as the operation thereof is based on pawls which mesh with th ratchet teeth as a result of centrifugal force. Accordingly, only in a very narrowly defined speed range can a shift be made from one drive source to the other drive source. Moreover, such SSS clutches cause a rattling sound in certain speed ranges during the shifting phase. The marine propeller drive system according to the invention offers the advantage that a shift can be made in th entire speed range of the marine propeller shaft. Accordingly in the case of disasters, for instance failure of one of the drive sources, the drive can be taken over immediately by another drive source via the infinitely variable, slipless freewheel clutch. The virtual noiselessness of the infinitely variable, slipless freewheel clutch, which operates utilizing eccentric discs, is of great importance, in particular for marine propeller drive systems of navy ships . In a third alternative further elaboration of the drive system, for combining power originating from several drive sources on a driven, rotation-and-torque receiving, single element, the drive system is characterized in that a pluralit of infinitely variable, slipless freewheel clutches are connected in series, while the output shaft of each of these infinitely variable, slipless freewheel clutches is connected to the input shaft of a next freewheel clutch, with the exception of the last infinitely variable, slipless freewheel clutch included in the series, which has its output shaft connected to the driven, rotation-and-torque receiving, single element, the input shaft of each freewheel clutch being dynamically connected to at least one driving, rotation-and- torque transmitting element and the respective infinitely variable, slipless freewheel clutches being controllable in such a manner that the speed of the output shafts thereof is tuned to the desired speed of the driving, rotation-and-torque transmitting element dynamically connected thereto. A drive system of such design offers the advantage that with few parts such as shafts and with few geared transmissions or similar transmissions, several drive sources can be connected to the driven, rotation-and-torque receiving, single element. This offers the advantage that upon actuation of the device only a minimum of mass inertia forces needs to be overcome and that, moreover, owing to the minor number of geared transmissions, only little power is lost through friction. Moreover, a drive system of such design offers the advantage that it occupies little space inasmuch as the infinitely variable, slipless freewheel clutches can be arranged in line. Further, when the infinitely variable, slipless freewheel clutches are provided with a fixed coupling possibility between the input and the output shaft thereof to effect a direct drive, upon failure of one of the drive sources, the input and the output shaft of the freewheel clutch associated with this drive source can be coupled via the fixed coupling possibility. Thus, any friction losses in the freewheel clutch which is no longer necessary owing to failure of the drive source, are eliminated. In some applications it can be desirable for the direction of rotation of the driven, rotation-and-torque receiving elements to be reversible. To that end, according to a further elaboration of the invention, at least one of the continuously variable, slipless freewheel clutches can be so designed that the direction of rotation of the output shaft thereof is reversible. In infinitely variable, slipless freewheel clutches which are connected in series, only the speed variator whose output shaft is connected to the driven, rotation-and-torque receiving element needs to be reversible. In freewheel clutches which are connected in parallel, however, each freewheel clutch which is connected to the driven, rotation- and-torque receiving, single element must be reversible. According to a further elaboration of the invention, the reversibility of the direction of rotation of the driven, rotation-and-torque receiving element is effected in that the respective unidirectional drive systems of the infinitely variable, slipless freewheel clutch the rotational direction of whose output shaft is reversible, are reversible in that they comprise a double-acting freewheel system which is adapted for driving the respective intermediate shafts in a first direction of drive and in a second, opposite direction of drive, the respective unidirectional drive systems being reversible only when the speed of rotation of the output shaft is zero. Such a drive system comprises at least one power receiving, driven element whose direction of rotation can be reversed, without additional sources of friction being introduced into the drive system. It should be noted that US 2 864 259 describes an infinitely variable, slipless freewheel clutch. However, this publication does not give any indication for the utilization of such an infinitely variable, slipless freewheel clutch for use in a drive system in which power originating from one drive source is distributed over several driven elements and/or in which power originating from several drive sources is combined on a driven, single element. The advantages of the invention - namely the possibility of avoiding the use of expensive friction or hydraulic clutches, thereby reducing the power losses to a minimum and still achieving a control range of the driven element or elements going steplessly from zero revolutions per second to a maximum value - are achieved in particular when the infinitely variable, slipless freewheel clutches are utilized in a drive system in which power is distributed or combined. To clarify the invention, five embodiments of a drive system will now be described, with reference to the accompanying drawings, in which: Fig. 1 is a sectional view of an infinitely variable, slipless freewheel clutch which can be used in one of the drive systems shown in the following figures; Fig. 2 is a sectional view taken on line II-II in Fig. 1; Fig. 3 is a schematic representation of a drive system in which the power of one drive source is distributed over several power receiving, driven elements; Fig. 4 is a schematic representation of a drive system in which power originating from several drive sources is combined via a plurality of parallel-connected infinitely variable, slipless freewheel clutches on a single, power receiving, driven element; Fig. 5 is an example of a practical application of the principle shown in Fig. 4; Fig. 6 is another example of a practical application of the principle shown in Fig. 4; and Fig. 7 is a schematic representation of a drive system in which power originating from several drive sources is combined via a plurality of series-connected infinitely variable, slipless freewheel clutches on a driven, rotation-and-torque receiving, single element. The drawings all relate to a drive system that comprises at least one drive source P which delivers its power by means of a driving, rotation-and-torque receiving, transmitting element T, at least one speed variator V and at least one driven, rotation-and-torque receiving element R. The drive system is characterized according to the invention in that, for distributing power originating from one drive source PI over several driven elements R1-R2 (see Fig. 3) and/or for combining power originating from several drive sources P1-P4 on a driven, rotation-and-torque receiving, single element R (see Figs 4-7), the or each speed variator V is designed as an infinitely variable, slipless freewheel clutch V having an input shaft 1 and an output shaft 9 (see Fig. 1) . The input shaft 1 comprises at least one pair of eccentric discs 2a, 2b, whose eccentricity can be varied, also during operation, from a neutral position of zero eccentricity to a maximum value by means of a control device 3 incorporated in the input shaft 1, the eccentricity of the respective discs 2a, 2b being mutually opposite. The infinitely variable, slipless freewheel clutch further comprises a plurality of circumferential units 4 located on a pitch circle S (see Fig. 2) whose centre coincides with the centreline HI of the input shaft 1 and which is located in, or in the vicinity of, a plane in which the eccentric discs 2a, 2b can oscillate during operation. The circumferential units 4 are each provided with a crank arm 5 which can be driven for oscillation by one of the eccentric discs 2a, 2b. The crank arms 5 of the respective circumferential units 4 are each dynamically connected to the output shaft 9 via at least one unidirectional drive system 6, consisting of a freewheel system 6, via respective intermediate shafts 7 and a transmission 8 with a fixed transmission ratio. The use of such infinitely variable, slipless freewheel clutches provides for great flexibility in regard of the number of drive sources and driven elements without necessitating the introduction of additional sources of friction, such as clutches and gearboxes and the like, into the drive system. Moreover, the infinitely variable, slipless freewheel clutches themselves exhibit low internal friction. pinion 10 provided on a common output shaft 9 of the respective freewheel clutches VI, V2, meshing with a gearwheel 11 located on the marine propeller shaft R. Another example of a drive system with a plurality of infinitely variable, slipless freewheel clutches V1-V4 connected in parallel is formed by the device shown in Fig. 6. Here, the driven, rotation-and-torque receiving element R is formed by a conveyor belt or chain of great length, which is driven at a plurality of points by the drive rollers 12 mounted on the output shaft 9 of the infinitely variable, slipless freewheel clutches V1-V4. The drive system shown schematically in Fig. 7 for combining power from several drive sources P1-P4 on a driven, rotation-and-torque receiving, single element R is characterized by a plurality of infinitely variable, slipless freewheel clutches V1-V4 which are connected in series. The output shaft 9 of each infinitely variable, slipless freewheel clutch V1-V3 in the series is connected to the input shaft 1 of a next freewheel clutch V2-V4, with the exception of the last infinitely variable, slipless freewheel clutch V4 included in the series, which has its output shaft 9 connecte to the driven, rotation-and-torque receiving, single element R. The input shaft 1 of each freewheel clutch V1-V4 is dynamically connected to at least one driving, rotation-and- torque transmitting element T1-T4 via, for instance, a gear o chainwheel transmission with respective transmission ratios ii~i 4 . The respective infinitely variable, slipless freewheel clutches V1-V4 can be so controlled that the speed i2θ) 2 -i 4 ύ 4 of the output shafts 9 thereof is tuned to the desired speed 0)2-0) 4 of the driving, rotation-and-torque transmitting elemen T1-T4 dynamically connected thereto. When the speed across th series of freewheel clutches V1-V4 runs up, i.e., when iιθ)χ is smaller than i 4 Cι 4 , use must be made of infinitely variable, slipless freewheel clutches V1-V4 whose transmission 8 betwee the intermediate shafts 7 and the output shaft 9 has an overdrive ratio. For some applications, it may be desirable for the direction of rotation of the rotation-and-torque receiving, driven element R to be reversible. In a drive system with parallel-connected freewheel clutches V1-V4 (Figs 4-6) , which are all dynamically connected to a driven, rotation-and-torque receiving, single element R, this can be effected by providing each freewheel clutch V1-V4 with an output shaft 9 whose direction of rotation is reversible. In a drive system with series-connected freewheel clutches V1-V4 (Fig. 7) , this can be effected by making only the last infinitely variable, slipless freewheel clutch V4 included in the series of such design that the direction of rotation of the output shaft 9 thereof can be reversed. A freewheel clutch V having an output shaft 9 whose direction of rotation is reversible comprises reversible unidirectional drive systems 6. To that end, the reversible unidirectional drive systems 6 comprise a double-acting freewheel system that is adapted for driving the respective intermediate shafts 7 in a first direction of drive and in a second, opposite direction of drive. The respective unidirectional drive systems 6 should be reversible only when the speed of rotation of the output shaft 9 of the freewheel clutch V is zero. It will be clear that the invention is not limited to the embodiment described, but that various modifications are possible within the framework of the invention. Thus, it is for instance possible for distributions and combinations of power to occur in a single drive system, for example a marine propeller drive which is connected, via parallel-connected freewheel clutches, to a main course turbine and a cross course turbine and of which a part of the power of the marine propeller shaft is taken off via a freewheel clutch for the benefit of auxiliary devices .

Claims: CLAIMS 1. A drive system comprising at least one drive source delivering its power by means of a driving, rotation-and- torque transmitting element, at least one speed variator and at least one driven, rotation-and-torque receiving element, characterized in that, for distributing power originating from one drive source (PI) over several driven elements (Rl, R2) and/or for combining power originating from several drive sources (P1-P4) on a driven, rotation-and-torque receiving, single element (R) , the or each speed variator (V) is designed as an infinitely variable, slipless freewheel clutch having an input (1) and an output shaft (9), the input shaft (1) being provided with at least one pair of eccentric discs (2a, 2b) whose eccentricity can be varied, also during operation, from a neutral position of zero eccentricity to a maximum value by means of a control device (3) incorporated in the input shaft (1), the eccentricity of the respective discs (2a, 2b) being mutually opposite, while a plurality of circumferential units (4) are arranged on a pitch circle (S) whose centre coincides with the centreline (HI) of the input shaft (1) and which is located in, or in the vicinity of, a plane in which the eccentric discs (2a, 2b) can oscillate during operation, said circumferential units (4) each comprising a crank arm (5) which can be driven for oscillation by one of the eccentric discs (2a, 2b) , the crank arms (5) of the respective circumferential units (4) each being dynamically connected to the output shaft (9) via at least one unidirectional drive system (6), consisting of a freewheel system (6), via respective intermediate shafts (7) and a transmission (8) with a fixed transmission ratio. 2. A drive system according to claim 1, characterized in that, for distributing power originating from one drive source (PI) over a plurality of driven elements (Rl, R2) , the driving element (TI) is dynamically connected to at least two infinitely variable, slipless freewheel clutches (VI, V2) whose output shafts (9) are each directly or dynamically connected to one of the driven, rotation-and-torque receiving elements (Rl, R2), with speeds (0)oι, 0)02) of the driven elements (Rl, R2) being controllable independently of each other. 3. A drive system according to claim 1, characterized in that, for combining power originating from several drive sources (P1-P4) on a driven, rotation-and-torque receiving, single element (R) , a plurality of infinitely variable, slipless freewheel clutches (V1-V4) are connected in parallel, the input shafts (1) of the freewheel clutches (V1-V4) each being connected to a rotation-and-torque transmitting, driving element (T1-T4) of one of the drive sources (P1-P4), and the freewheel clutches (V1-V4) being controllable in such a way that the speeds (0)o/ii~0)o/i ) of the output shafts (9) thereof, which are each dynamically connected to the driven, rotation-and-torque receiving, single element (R) , are tuned to the desired speed (O)o) of this driven element (R) . 4. A drive system according to claim 3, characterized in that the drive sources (PI, P2) are marine turbines or marine motors, while the driving, rotation-and-torque transmitting elements (TI, T2) are output shafts of the marine turbines or marine motors and the driven, rotation-and-torque receiving, single element (R) is a marine propeller shaft. 5. A drive sytem according to claim 1, characterized in that, for combining power originating from several drive sources (P1-P4) on a driven, rotation-and-torque receiving, single element (R) , a plurality of infinitely variable, slipless freewheel clutches (V1-V4) are connected in series, said infinitely variable, slipless freewheel clutches (V1-V3) having their output shaft (9) connected to the input shaft (1) of a next freewheel clutch (V2-V4) , with the exception of the last infinitely variable, slipless freewheel clutch included in the series (V4), which has its output shaft (9) connected to the driven, rotation-and-torque receiving, single element (R) , the input shaft (1) of each freewheel clutch (V1-V4) being dynamically connected to at least one driving, rotation- and-torque transmitting element (T1-T4), and the respective infinitely variable, slipless freewheel clutches (V1-V4) being controllable in such a manner that the speed (i2θ) 2 -i 4 θ) 4 ) of the output shafts (9) thereof is tuned to the desired speed (0) 2 -0) 4 ) of the driving, rotation-and-torque transmitting element (T2-T4) dynamically connected thereto. 6. A drive system according to any one of the preceding claims, characterized in that at least one of the infinitely variable, slipless freewheel clutches (V1-V4) is so designed that the direction of rotation of the output shaft (9) thereof is reversible. 7. A drive system according to claim 6, characterized in that the respective unidirectional drive systems (6) of the infinitely variable, slipless freewheel clutch (V1-V4) the rotational direction of whose output shaft (9) is reversible, are reversible in that they comprise a double-acting freewheel system (6) which is adapted for driving the respective intermediate shafts (7) in a first direction of drive and in a second, opposite direction of drive, said respective unidirectional drive systems (6) being reversible only when the speed of rotation of the output shaft (9) is zero.

Inventors: MASONI PIETRO, MASONI, PIETRO
Applicants: MASONI PIETRO, MASONI, PIETRO
Application year: 1993
Main classification: F16H37
IPC codes: B63H23, F16H29, F16H37