EXTREME TRANSMISSION RATIO EFFICIENT MECHANISM

Abstract

Currently, there is no efficient mechanism for speed increasing with very high transmission ratio. Therefore, a planetary mechanism is proposed, with two suns (0b, 3b), having teeth numbers: Z.sub.1,Z.sub.4, one stationary (0b) and one (3b) constituting the input of mechanism, a carrier (1a, 1b, 1c, 1d) constituting the output, and a planetic shaft (2b) with two planets (2a, 2c), cooperating with corresponding suns (0b, 3b) and having teeth numbers: Z.sub.2,Z.sub.3, where the term: Z.sub.1/Z.sub.2.Z.sub.3/Z.sub.4 is closest to 1, so the transmission ratio between moving sun (3b) and carrier (1a, 1b, 1c, 1d) is maximum possible. In a specific case, named “Three Successive Integers Mechanism”, this transmission ratio is equal to k.sup.2, where k is integer, easily taking high value. The applications are unlimited, while some are: —wind turbine, —electric assisted bicycle, —energy storage unit of enormous kinetic energy with k.sup.4 times increased moment of inertia, —mechanically driven supercharger for ICE or fuel cell, —robotic articulated arm (as speed reducer).

Claims

1. Extreme Transmission Ratio Mechanism, being a planetary mechanism, consisting of: a conventionally stationary frame (0a), a first gear, named “reaction sun” (0b), rigidly connected to the frame (0a), the axis of rotation of which is named “central axis”, having a teeth number Z.sub.1, a second gear, named “action sun” (3b), supported on the frame (0a) coaxially with the central axis and being able to rotate freely and endlessly about the central axis, having a teeth number Z.sub.4, while the action sun (3b) is the input or the output of this Extreme Transmission Ratio Mechanism, in case of speed increasing or speed reducing, respectively, a carrier (1a, 1b, 1c, 1d), supported on the frame (0a) coaxially with the central axis and being able to rotate freely and endlessly about the central axis, while the carrier (1a, 1b, 1c, 1d) is the output or the input of this Extreme Transmission Ratio Mechanism, in case of speed increasing or speed reducing, respectively, on the carrier (1a, 1b, 1c, 1d), parallel to the central axis, at a distance from the central axis, equally angularly distributed around the central axis, there is a plurality of axes, each of them named “planetic axis”; a shaft, named “planetic shaft” (2b), is corresponding to each of these planetic axes, supported on the carrier (1a, 1b, 1c, 1d) coaxially with its corresponding planetic axis and being able to rotate freely and endlessly about this planetic axis, with a third gear, named “reaction planet” (2a), rigidly connected to the one end of this planetic shaft (2b) coaxially with this planetic axis, cooperating with the reaction sun (0b), having a teeth number Z.sub.2, and with a fourth gear, named “action planet” (2c), rigidly connected to the other end of this planetic shaft (2b) coaxially with this planetic axis, cooperating with the action sun (3b), having a teeth number Z.sub.3, while this mechanism is characterized by the following: the teeth numbers of all these four gears satisfy the relation: (Z.sub.1−Z.sub.2)*(Z.sub.4−Z.sub.3)>0, (Z.sub.1+Z.sub.2)*module.sub.R=(Z.sub.4+Z.sub.3)*module.sub.A, where module.sub.R is the module of the gears pair: reaction sun (0b) and reaction planet (2a), and module.sub.A is the module of the gears pair: action sun (3b) and action planet (2c), the toothing profiles of all these four gears are either the involute, or the cycloidal of any type, or any other type of conjugate profiles, straight or helical.

2. Extreme Transmission Ratio Mechanism, according to claim 1, being characterized by that the teeth numbers of the gears satisfy the relation:
(Z.sub.1−Z.sub.2)*(Z.sub.4−Z.sub.3)*(Z.sub.4−Z.sub.1)=1, or: (Z.sub.1−Z.sub.2)*(Z.sub.4−Z.sub.3)*(Z.sub.1−Z.sub.4)=1.

3. Extreme Transmission Ratio Mechanism, according to claim 1 or claim 2, being characterized by that the reaction sun (0b), remaining supported on the frame (0a) coaxially with the central axis, can freely and endlessly rotate about the central axis, either before or during the operation for which this Extreme Transmission Ratio Mechanism has been designed, in synchronization with this operation or independently.

4. Extreme Transmission Ratio Mechanism, according to claim 1 or claim 2 or claim 3, being characterized by that it is applied as a speed reducer on the transmission mechanism of an articulated arm of a robot.

5. Extreme Transmission Ratio Mechanism, according to claim 1 or claim 2 or claim 3, being characterized by that it is applied as a speed increaser on the transmission mechanism of a supercharged device, such as an internal combustion engine or a fuel cell, transmitting power from the crank-shaft of the internal combustion engine or the shaft of an electric motor, respectively, to the shaft of the air or the oxygen supercharger, respectively.

6. Extreme Transmission Ratio Mechanism, according to claim 1 or claim 2 or claim 3, being characterized by that it is applied as a speed increaser on the transmission mechanism of a wind turbine, transmitting power from the propeller shaft of the wind turbine to the shaft of an electric generator.

7. Extreme Transmission Ratio Mechanism, according to claim 1 or claim 2 or claim 3, being characterized by that it is applied as a speed increaser on the transmission mechanism of a slow work-generating device, such as a thermal engine, especially a Stirling engine, transmitting power from the output shaft of the work-generating device to the shaft of an electric generator.

8. Extreme Transmission Ratio Mechanism, according to claim 1 or claim 2 or claim 3, being characterized by that the carrier (1a, 1b, 1c, 1d) of this Extreme Transmission Ratio Mechanism is coincident with the rotor of an electric device which is either an electric motor, or an electric generator, or both, alternatively, either transmitting power from the shaft of the electric motor to the shaft of a slow work-generating device, such as the motion mechanism of a human powered vehicle, especially a bicycle, in order to assist this work generation, or transmitting power from the shaft of the work-generating device to the shaft of the electric generator.

9. Extreme Transmission Ratio Mechanism, according to claim 1 or claim 2 or claim 3, being characterized by that the carrier (1a, 1b, 1c, 1d) is a rotating part, such as a flywheel, within a mechanical system which is a storage unit of kinetic energy, where sometimes the action sun (3b) is the input of this mechanical system and gives energy to this storage unit and sometimes the action sun (3b) is the output of this mechanical system and receives energy from this storage unit, depending on the requirements of the operation for which this Extreme Transmission Ratio Mechanism has been designed.

10. Extreme Transmission Ratio Mechanism, according to claim 1 or claim 2 or claim 3 or claim 5 or claim 6 or claim 7 or claim 8 or claim 9, being characterized by that the carrier (1a, 1b, 1c, 1d), being either the output of this Extreme Transmission Ratio Mechanism or the rotating part of the Extreme Transmission Ratio Mechanism of claim 9, is connected to a starter (4), either via a clutch or via a unidirectional power transmission, so that, after starting this Extreme Transmission Ratio Mechanism, the starter (4) can be disengaged, except in the case that the starter (4) is both an electric motor, or an electric generator, alternatively, and after starting it goes into generator mode.

Description

[0081] The Drawings present:

[0082] FIG. 1: the mechanism with one planetic unit and a counter-weight.

[0083] FIG. 2: a more complete version of the mechanism with five planetic units.

[0084] FIG. 3: the mechanism with five planetic units in an exploded view without bearings and bolts.

[0085] FIG. 4: a side view and the section A-A of the mechanism with five planetic units; for better understanding of this Drawing, where the parts are rigidly connected together, their cross-hatches are the same in density and angle.

[0086] FIG. 5: a front view and the section B-B of the mechanism with five planetic units.

[0087] In these Drawings, the Parts are denoted as follows: [0088] Body “0”: Stationary Frame [0089] 0a: Frame in general [0090] 0b: Reaction Sun [0091] 0c: Bolt that rigidly connects the Reaction Sun to the Frame [0092] Body “1”: Rotating Carrier [0093] 1a: Carrier Disk with the Toothing for peripheral external connection [0094] 1b: Bar which rigidly connects the two Disks of the Carrier [0095] 1c: Carrier Disk with the Pulley for peripheral external connection [0096] 1d: Carrier Flange for axial external connection [0097] Body “2”: Rotating Planetic Unit [0098] 2a: Reaction Planet [0099] 2b: Planetic Shaft [0100] 2c: Action Planet [0101] 2d: Bolt that rigidly connects the Reaction Planet and the Action Planet to the Planetic Shaft [0102] Body “3”: Rotating Action Sun [0103] 3a: Shaft for external connection of the Action Sun [0104] 3b: Action Sun [0105] 3c: Bolt that rigidly connects the Action Sun to its Shaft for external connection [0106] 4: Starter—it can be an Electric Motor only, or an Electric Motor or an Electric Generator, alternatively

[0107] In general, this planetary mechanism has a frame (0a), which conventionally is either stationary or movable in space.

[0108] Rigidly connected to the frame there is a gear, named “reaction sun” (0b), the axis of which is named “central axis”, and with a teeth number Z.sub.1.

[0109] Coaxially with the central axis there is also another gear, named “action sun” (3b), supported on the frame, being able to freely and endlessly rotate about the central axis and with a teeth number Z.sub.4.

[0110] Coaxially with the central axis, finally, there is a carrier (1a, 1b, 1c, 1d), supported on the frame and being able to freely and endlessly rotate about the central axis, as well.

[0111] This carrier has a plurality of axes, each of them being named “planetic axis”, parallel to the central axis and at a distance L from it, common for all planetic axes, and equally angularly distributed around the central axis (FIG. 5).

[0112] There is a number of shafts, equal to the number of the planetic axes, each of them being named “planetic shaft” (2b), being coaxial with its own planetic axis, and supported on the carrier being able to freely and endlessly rotate about its own planetic axis.

[0113] On each planetic shaft there is a gear, named “reaction planet” (2a), coaxially with its respective planetic axis and rigidly connected to the one end of the planetic shaft, which cooperates with the reaction sun, and with a teeth number Z.sub.2.

[0114] On each planetic shaft there is, also, a gear, named “action planet” (2c), coaxially with its respective planetic axis and rigidly connected to the other end of the planetic shaft, which cooperates with the action sun, and with a teeth number Z.sub.3.

[0115] Each planetic shaft, the reaction planet and the action planet form a unit, named “planetic unit”.

[0116] Only one such planetic unit is necessary to be used, as long as there is a properly designed counter-weight to achieve the static and dynamic balancing of the mechanism (FIG. 1).

[0117] On the contrary, the maximum number of these planetic units is five (FIG. 2, FIG. 3, FIG. 4 and FIG. 5), so that their deployment remains at the same plane, while the best possible load distribution in more cooperating teeth, at the same time, ensures the required strength with a smaller tooth width, and thus the best possible use of space is achieved.

[0118] The large number of planetic units also favors the increasing of the moment of inertia of the carrier as a whole, a situation which is particularly desirable in some applications.

[0119] As mentioned above, the mathematical term: Z.sub.1/Z.sub.2*Z.sub.3/Z.sub.4 is forced to be as close to 1 as possible, without, however, being equal to it, so that the transmission ratio between the action sun and the carrier is rendered the highest possible.

[0120] The following relation applies for the modules:

(Z.sub.1+Z.sub.2)*module.sub.R=(Z.sub.4+Z.sub.3)*module.sub.A,

[0121] as well as the relative note, on the standardization of the modules to reduce the construction cost, apply. The toothing profiles of all these gears can be the involute, the cycloidal of any type (hypocycloidal, epicycloidal, full or parts of them), or any other type of conjugate profiles, straight or helical.

[0122] When this mechanism is used as a speed reducer, the carrier is the input of the mechanism and the action sun is the output of the mechanism.

[0123] However, this mechanism is mainly intended to be used as a speed increaser, so, in this case the action sun is the input of the mechanism and the carrier is the output of the mechanism.

[0124] Finally, the carrier, either as the input or the output of the mechanism, may be connected to external machines either by a formation on its central shaft (1d), or by a peripheral toothing (1a) or even by a peripheral pulley (1c), as in FIG. 2, FIG. 3, FIG. 4 and FIG. 5.

[0125] The shaft (3a), to which the action sun is rigidly connected, can penetrate—there is enough space for the required strength of all involved elements—the specially shaped central shaft of the carrier (1d), internally through its core, so the carrier can be connected to external machines in all possible ways, that means either coaxially with the action sun and on the same side, in the way that just described, or coaxially with the action sun and on the opposite side, or peripherally.

[0126] This last way of connection—peripherally—will obviously be preferred under very high load conditions, since in this case both, the action sun and the carrier, can be mounted in the most robust manner.

[0127] A more specific implementation of the just presented mechanism is achieved by the appropriate application of the “Three Successive Integers Conjecture” to the teeth numbers of the involved gears, so that, as mentioned above, the transmission ratio between the action sun and the carrier is: 1:k.sup.2.

[0128] The following relation, also, applies for the modules:

(2*k+1)*module.sub.R=(2*k−1)*module.sub.A.

[0129] As is well known, the apparent moment of inertia, as it appears from the side of the slower moving part of a mechanism in which power is transmitted by a transmission ratio: “a”, is equal to the moment of inertia of the other side multiplied by the square of this transmission ratio, namely: “a.sup.2”, hence the apparent moment of inertia: “I.sub.CA” of the carrier from the side of the action sun and the moment of inertia: “I.sub.C0” of the carrier, are correlated by the relation: I.sub.CA=k.sup.4*I.sub.C0.

[0130] After this exhaustive presentation, some more specialized applications of this mechanism will be presented:

[0131] Reducers or Increasers, alternatively: [0132] An electro-reducer—that is an electric motor with an embedded reducer—where the carrier of this mechanism is the rotor of the electric motor; a good application example of this configuration is the electro-reducer that assists the movement of a bicycle.

[0133] There is, also, the reversed mechanism, that means an electric generator with an embedded increaser, where the carrier, again, of this mechanism is the rotor of the electric generator; a good example, also, is a bicycle with this electric generator which transforms the work—partially or in total—that is produced by the cyclist to electric energy, which is accumulated in a battery, and which, in turn, supplies an electro-reducer that assists the movement of the bicycle, in other periods.

[0134] The ideal configuration, of course, is an electric device which is both, an electric motor or an electric generator, alternatively, the rotor of which, again, is the carrier of this mechanism and its action sun is connected—rigidly or not—to the shaft of the cooperating machine; which, in the cases of the above examples is the crank-shaft of the bicycle. [0135] An energy storage unit, which can be named “Inertial Battery Mechanism”, in which the carrier is a terminal body, that means neither an input nor an output, in a mechanical system which is a unit of storage of a significant amount of kinetic energy, part of which may be returned to the action sun, which is both, the only input or the only output of the mechanism, depending on the requirements of the operation. It is obvious that the use of five planetic units duly magnifies the moment of inertia, catapulting the apparent moment of inertia to a level, orders of magnitude higher than when using the classic flywheel.

[0136] A good application example of this, is a light human powered vehicle, a bicycle for instance, during the operation of which in some periods, for instance in a downhill road, kinetic energy is stored in this inertial accumulator, and in other periods, for instance in an uphill road, it is returned to the vehicle wheels. Another good example is a wind turbine, during the operation of which in some periods, when the wind drives its blade-shaft, the whole or a part of kinetic energy is stored in this inertial accumulator and in other periods, when there is no sufficient wind action, it drives the electric generator.

[0137] Reducers:

[0138] For the movements of an articulated arm of a robot; using the perfect involute is more robust and efficient than its competitors.

[0139] For any other classic application of a speed reducer.

[0140] Increasers for the increasing of the speed of: [0141] the crank-shaft of an internal combustion engine with mechanically driven supercharger, from a few thousands of RPM to hundreds of thousands of RPM, in order to supercharging air into the engine, [0142] the shaft of an electric motor, from a few thousands of RPM to hundreds of thousands of RPM, in order to supercharging oxygen into a fuel cell, [0143] the blade-shaft of a wind turbine, from a few RPM to a few thousands of RPM, in order to drive an electric generator; being a single-stage planetary mechanism, it is therefore more compact, robust and efficient than its competitors, [0144] the shaft of a thermal engine, a Stirling one for example, from a few RPM to a few thousands of RPM, in order to drive an electric generator.

[0145] Finally, another interesting application could be a speed increaser which transmits power from a machine which produces mechanical work, with an operating frequency of one cycle per day or 1/1,440 RPM (geo-frequency), to an electric generator which operates at a frequency of a few thousands of RPM.

[0146] The machine, which produces mechanical work with geo-frequency, could be named: “Geo-Frequency Engine”, and could be, also, of any kind; an example, however, of such a machine is an even solid state device with an element, the length or the volume of which increases during the day, receiving heat, while this element returns to its original state overnight, discharging a part of this heat.

[0147] In this way, thermal insulation materials are not required for the purpose of isolating the hot area and the cold area, as well as complex mechanisms are not required for the movements of the parts, which produce the mechanical work, from the hot area to the cold area and vice versa.

[0148] In this version of this mechanism, the design suggests the use of five planetic units, each of which carries two heavy planets, thus making the involved moment of inertia already very large, rendering therefore the apparent moment of inertia literally enormous.

[0149] This huge moment of inertia receives and successfully manages any deviation in the work-generating schedule, compared to the designed one, due to the inevitable variation of critical parameters during the twenty-four hours operation.

[0150] Being more specific, three successive integers can be used and the integer k can be set as: k=1,200, so the transmission ratio is: 1:1,440,000 and the carrier rotates at a frequency of 1,000 RPM, a rather sufficient value for an electric generator.

[0151] The construction of such a machine today is just a scenario of scientific fiction, mainly due to the current technology of materials; however, in the future, the crucial relevant problems may be solved.

[0152] In all above cases of speed increasing with high transmission ratio, due to the huge apparent moment of inertia, it is just impossible to start the mechanism from the side of the action sun and thus the presence of a starter (4) is required, which is connected to the carrier either by a clutch or by a unidirectional transmission mechanism, so that after starting the mechanism this starter can be disengaged.

[0153] The starter can be even a complete electric device with the capability to be both, an electric motor or an electric generator, alternatively, so that after starting it goes into generator mode, thus reducing the number of components involved, and therefore the complexity of the mechanism and its weight.

[0154] Another case is that the starter is connected via the peripheral pulley or via a second peripheral toothing, which is in the location of the pulley, and the electric generator alone is connected via the already depicted peripheral toothing.

[0155] It is relatively easy to construct, using common materials and manufacturing of medium precision requirements, a single-stage speed reducer with the dimensions of a medium-size wall clock and a transmission ratio: 1:1,000,000.

[0156] However, the greatest challenge is to design and construct a speed increaser, with the most proper existing components and materials for manufacturing with the best precision requirements for dimensions and roughness, and with special coatings on the working sides of the teeth of the gears, in order to produce an efficient single-stage speed increaser with a ratio much higher than 1:100, for use in the field of the wind turbines, and not only.

[0157] Advantages:

[0158] The most significant advantages are the incomparable simplicity of the whole mechanism and the use of the perfect involute.

[0159] In its basic version, this mechanism includes only three moving parts, namely the action sun, the carrier and the planetic unit.

[0160] Moreover, its operation is based on the cooperation of only two pairs of cooperating gears.

[0161] As a result, the highest possible degree of efficiency is achieved for both operations, either to reduce or to increase the speed, and moreover this mechanism is rendered unique to be an efficient speed increaser.

[0162] All parts can be already existing components, except the two non-standard gears.

[0163] In fact, these two gears are standard ones with a scale factor: (2*k+1)/(2*k−1), or: (2*k−1)/(2*k+1), both scale factors being very close to 1, so for a medium level mass production the cost of them can be less than 110% of the cost of the standard gears; however, the cost of the whole mechanism according to the present invention can be easily less than the 50% of the cost of the whole mechanism according to the prior state of the art, for the same purposes and requirements.

[0164] So, this mechanism is characterized by easy construction, as well as easy and cost-effective operation and maintenance.

[0165] By just its design per se, this mechanism is limited in size, however with the addition of more planetic units and specifically with the use of up to five such planetic units, the load to be received by the involved teeth is ideally distributed to more simultaneously cooperating teeth pairs and thus achieves the minimum, allowed by the strength requirements, width of the toothings, with the best possible space exploitation. Additionally, it is very important that, also by the design of this mechanism per se, the most balanced arrangement of the diameters of the gears is achieved, as a result of which the usual—and particularly problematic in relative cases, being also the weakest link in any power train—pinion is absolutely absent.

[0166] Regarding the application of this mechanism as a temporary—but even with a longer duration—energy storage unit, this proposal is superior to the classic flywheel, as for the same mass—therefore volume and weight—the apparent moment of inertia of the carrier as a whole—that is with all planetic units—is k.sup.4 times greater, with correspondingly huge margins of energy storage.

[0167] These advantages make this mechanism the ideal option for any case where an increasing of speed is required; however, in any case, also, where a drastic reduction of speed is required, this mechanism is superior to its existing competitors.

[0168] In conclusion, these are a number of merits which are easily contrasted as advantages over a competition, which, in fact, is rather moderate.