Cycloidal rotor

Abstract

The invention provides a cycloidal rotor, having a main axis (0), extension arms (1) rotatable around the main axis (0) and arranged in a star configuration, and aerofoils (2) rotationally connected to the extension arms (1), wherein the aerofoils (2) are coupled rotationally with the rotation of the extension arms (1) via a gear transmission (P) so that the gear ratio between the rotation of the extension arms (1) and the rotation of the aerofoils (2) is 2:1, characterized in that the gear transmissions (P) are gear transmissions (P) for inducing variable rotational speed of the aerofoils (2) relative to the rotational speed of the extension arms (1), wherein each of the gear transmissions (P) induces a slowed down rotation of the corresponding aerofoil (2) relative to the extension arm (1) when the aerofoil (2) is perpendicular to the extension arm (1), and an accelerated rotation of the aerofoil (2) relative to the extension arm (1) when the aerofoil is parallel to the extension arm (1).

Description

[0001] Cycloidal rotor

[0002] The invention provides a cycloidal rotor having a main axis, extension arms rotatable around the main axis and arranged in a star configuration, and aerofoils coupled rotationally with the rotation of the extension arms via a gear transmission so that the gear ratio between the rotation of the extension arms and the rotation of the aerofoils is 2: 1.

[0003] In the art, cycloidal rotors used to propel air and water vehicles are known. Their general construction includes a main axis around which star-configured extension arms connected rotationally to aerofoils rotate. In order to obtain the best propelling effect, the rotation of the aerofoils is coupled with the rotation of the extension arms so that the gear ratio between the rotation of the extension arms and the rotation of the aerofoils is 2: 1. For this purpose, toothed gear transmissions, belt transmissions and transmissions combined of these two kinds are most commonly used.

[0004] From document US3134443A a mechanism is known for controlling rotation of the blades 7 of a cycloidal rotor 6, comprising an immovable central toothed wheel 32, toothed wheels 35 rigidly connected to the blades 7, and intermediate wheels 34. The gear ratio between the wheel 32 and the wheel 35 is 2: 1. Document US3639077A discloses a gear transmission mechanism of a cycloidal rotor, comprising a set of toothed wheels and belts. Also document RU2060203C1 discloses a gear transmission mechanism of a cycloidal rotor, in which the gear ratio between the central wheel and the blade wheels is 2: 1.

[0005] The constructions described provide the following effect:

[0006] - each aerofoil is arranged approximately perpendicularly to the direction of the thrust force, when it moves in direction opposite to its direction, i.e. pushes the medium with its entire surface,

[0007] - each aerofoil is arranged approximately in parallel to the direction of the thrust force, when it moves along the direction of the thrust force, i.e. provides low resistance. The above described cycloidal rotors of the prior art show a uniform rotational motion of the aerofoils, i.e. the rotational speed of the aerofoils is the same along their entire turn. Therefore, the aerofoils, in their intermediate positions, are arranged angularly relative to the thrust force, and the angle changes uniformly according to the mentioned gear transmission ratio of 2:1. In the angular positions, the aerofoils are not positioned optimally to maximize the thrust force. The present invention solves this problem by providing a mechanism which changes the characteristics of rotation of the aerofoils around their axes by slowing down the rotation of the aerofoils when they are perpendicular to the extension arm, and by accelerating the rotation of the aerofoils when they are parallel to the extension arms. This also encompasses holding up completely of the rotation of the aerofoil in a segment of the turn of the extension arm around the axis of the rotor. Hence, each aerofoil during a half of the turn of the rotor is positioned substantially perpendicularly to the thrust force, while during the second half of the turn - substantially perpendicularly to the extension arm to maximize effectiveness of the rotor.

[0008] The invention provides a cycloidal rotor having a main axis, extension arms rotatable around the main axis and arranged in a star configuration, and aerofoils rotationally connected to the extension arms, wherein the aerofoils are coupled rotationally with the rotation of the extension arms via a gear transmission so that the gear ratio between the extension arms rotation and the aerofoils rotation is 2: 1, characterized in that the gear transmissions are gear transmissions for inducing variable aerofoils rotational speed relative to the extension arms rotational speed, wherein each of the gear transmissions induces a slowed down rotation of the respective aerofoil relative to the extension arm when the aerofoil is perpendicular to the extension arm, and an accelerated rotation of the aerofoil relative to the extension arm when the aerofoil is parallel to the extension arm.

[0009] Preferably, the rotor comprises, on the main axis, a main gear transmission element, coupled rotationally with each of the aerofoils via the gear transmission.

[0010] More preferably, the main gear transmission element is independently rotatable on the main axis relative to the extension arms, to induce a direction change of the rotor thrust. Also more preferably, the main gear transmission element is a main wheel, and each gear transmission comprises: a first wheel coupled counter-rotationally with the main wheel, a second wheel coupled counter-rotationally with the first wheel, the second wheel being rotationally coupled in a concurrent manner with the aerofoil.

[0011] Even more preferably, the wheels are toothed wheels and the second toothed wheel is coupled rotationally with the aerofoil via a first auxiliary wheel that is coaxial and coupled rotationally therewith, as well as a second auxiliary wheel coupled via an endless connector with the first auxiliary wheel, and coaxial and coupled rotationally with the aerofoil.

[0012] Also more preferably, the wheels are toothed wheels, each toothed wheel being coupled rotationally with the aerofoil via an additional toothed wheel therebetween.

[0013] Still more preferably, the first toothed wheel or the main toothed wheel comprise means for holding up rotation of the first toothed wheel for a segment of the turn around the main toothed wheel.

[0014] Most preferably, the means for preventing the first toothed wheel and the main toothed wheel from coupling comprise a partially toothless profile of the main toothed wheel and sliding means of the first toothed wheel.

[0015] More preferably, the wheels are eccentrically rotatable and non-circular, while the second wheel has a central rotation axis and is non-circular.

[0016] Still more preferably, the wheels are elliptical.

[0017] Also still mote preferably, the wheels are toothed wheels.

[0018] Preferably, the gear transmission is equipped with a Geneva mechanism.

[0019] More preferably, the Geneva mechanism comprises a main wheel, a first wheel and pins, wherein the main wheel and the first wheel have mutually corresponding arcuate profiles for rotational engagement of the wheels, and furthermore, the first wheel has gaps to be engaged with the pins to hold up rotation of the first wheel in a segment of its turn.

[0020] The subject-matter of the invention is shown in embodiments in the drawings, where fig. 1 shows a general view of a rotor according to the invention in an embodiment, fig. 2 shows schematically an arrangement according to this embodiment of an extension arm with the aerofoil and the gear transmission as well as the controller, fig. 3 shows schematically an embodiment of a rotor according to the invention, along with a motion scheme, fig. 4 shows schematically an embodiment of the rotor of fig. 1, along with a motion scheme, fig. 4a shows an embodiment of the gear transmission of fig. 1 and fig. 4, fig. 5 shows schematically another embodiment of a rotor, along with a motion scheme, and fig. 5a shows a portion of the embodiment of the gear transmission of fig. 5.

[0021] A shown in the drawings, a cycloidal rotor according to the invention has a main axis 0, extension arms 1 rotatable around the main axis and arranged in a star configuration, and aerofoils 2 rotationally connected to the extension arms 1 (here, aerofoils 2 are connected at the ends of the extension arms 1, nevertheless they may be also connected closer to the centres thereof). The aerofoils 2 are coupled rotationally with rotation of the extension arms 1 via a gear transmission P so that the gear ratio between rotation of the extension arms 1 and the rotation of the aerofoils 2 is 2: 1. The invention is characterized in that the gear transmissions P are gear transmissions P for inducing variable rotational speed of the aerofoils 2 relative to the rotational speed of the extension arms 1, wherein each of the gear transmissions P induces slowed down rotation of the corresponding aerofoil 2, when it is perpendicular to the extension arm 1, and accelerated rotation of the aerofoil 2, when it is parallel to the extension arm 1.

[0022] The principle of operation of the invention is as follows:

[0023] - one turn of the extension arm 1 around the axis 0 translates to exactly half of turn of the aerofoil 2 around its axis; - when the aerofoil 2 moves within the medium in the direction of the assumed aerodynamic lift then the aerofoil 2 is positioned approximately perpendicularly to the extension arm 1, and thus the resistance force of the medium applied thereto is minimized;

[0024] - when the aerofoil 2 moves within the medium in a direction opposite to the assumed aerodynamic lift then the aerofoil 2 is positioned approximately perpendicularly to the direction of the force, and thus the resistance force of the medium applied thereto is maximized; this is the same aerodynamic lift that the rotor applies to the vehicle.

[0025] The principle of efficiency maximization, going beyond the prior art:

[0026] - the aerofoil 2 rotates slowly or does not rotate at all relative to the extension arm 1 when the aerofoil moves in the direction of the aerodynamic lift (at the same time it is positioned approximately perpendicularly to the extension arm);

[0027] - the aerofoil 2 rotates slowly or does not rotate at all relative to the vehicle when the aerofoil moves in a direction opposite to the direction of the aerodynamic lift (while it is positioned approximately perpendicularly to this force).

[0028] The figures of the drawing show embodiments in which the gear transmissions P are gear transmissions comprising toothed wheels in a linear arrangement along the extension arm 1. A person skilled in the art will surely note that some other kind of gear transmissions that the one comprising toothed wheel may be used; furthermore, the elements of the gear transmission not necessarily have to be arranged linearly along the extension arm, but this variant will be optimal in most cases.

[0029] The embodiments shown in the figures have four extension arms 1 and correspondingly four aerofoils 2, but here a person shilled in the art may note that the rotor may have other number of such elements, e.g. three or five, according to the use. For big rotors, there may be even more such elements. Contrary to the examples shown in the figures, wherein the aerofoils 2 are rotationally connected at both ends to the pairs of the mutually corresponding extension arms 1, also aerofoils 2 connected to a corresponding single extension arm 1 at one end only of the aerofoil 2 may be used. The embodiments presented in figs. l-4a have the same arrangement of elements so that in the main axis 0 a main toothed wheel 3 is arranged, and each gear transmission P comprises in succession, arranged linearly along the extension arm 1: a first toothed wheel 4 meshed with the main toothed wheel 3, a second toothed wheel 5 meshed with the first toothed wheel 4, wherein the second toothed wheel 5 is coupled rotationally with the aerofoil 2.

[0030] In these embodiments, the second toothed wheel 5 is coupled rotationally with the aerofoil 2 via a first auxiliary wheel 6 that is coaxial and rotationally coupled therewith, and a second auxiliary wheel 7 coupled via an endless connector 8 (e.g. a belt or chain) with the first auxiliary wheel 6, and coaxial and coupled rotationally with the aerofoil 2.

[0031] In some (not shown) embodiment, in lieu of coupling via an endless connector, the second toothed wheel 5 is coupled rotationally with the aerofoil 2 via an additional toothed wheel interposed between them. More intermediate toothed wheels may be also used as well as another kind of coupling, as will be clear for a person skilled in the art.

[0032] In the embodiment shown in figs. 1, 2, 4, 4a, the first toothed wheel 4 or the main toothed wheel 3 comprises means for holding up rotation of the first toothed wheel 4 in a segment of the turn around the main toothed wheel 3. The means comprise in this example a partially toothless profile 10 of the main toothed wheel 3 and sliding means 11 of the first toothed wheel 4 as best seen in fig. 4a where also operational scheme of such embodiment is shown. A person skilled in the art will note that also other means known in the art for partial holding up of rotation of the first toothed wheel 4 around the main toothed wheel 3 may be used.

[0033] Coupling between the wheels 3 and 4 is such that when the wheel 4 is at one side of the wheel 3, it is coupled therewith as a toothed wheel, while when at the other side, it is stationary relative to the extension arm 2.

[0034] When the aerofoil 2 moves in the direction of the aerodynamic lift then the sliding means 11 connected rigidly to the element 4 slide upon the toothless profile 10 of the wheel 3. As a result, the wheel 4 is stationary relative to the extension arm 1. Thus the aerofoil 2 is also stationary relative to the extension arm 1.

[0035] When the aerofoil 2 moves in the direction opposite to the aerodynamic lift then the wheels 3 and 4 are meshed and the wheel 4 rotates around its axis seated in the extension arm 1 in opposite direction and with the same rotational speed with which the extension arm 1 moves around its axis. Thus, the aerofoil 2 is constantly perpendicular to the direction of the aerodynamic lift.

[0036] The main toothed wheel 3 may be non-rotational relative to the extension arms 1 (one thrust direction) or it may be rotational independently of the extension arms, via a controller 9 (shown in fig. 2) connected operatively thereto, to change the thrust direction.

[0037] Fig. 3 shows an embodiment of the invention wherein the toothed wheels 3, 4 are rotational eccentrically and non-circular, while the second toothed wheel 5 has a central rotation axis and is non-circular. Here, specifically, the toothed wheels 3, 4 are elliptic, but also some other shape may be used which would meet the motion prerequisites for the aerofoils.

[0038] The toothed wheel 4 has the same number of teeth as the toothed wheel 3, and the toothed wheel 5 has twice as much teeth as the element 3. When the aerofoil 2 moves in the direction of the aerodynamic lift, the centres of the toothed wheels 3 and 4 are at the opposite side than the aerofoil 2, relative to their axes. At the same time, the toothed wheel 5 is arranged with its major axis along the extension arm 1. This arrangement causes that the aerofoil 2 rotates slowly and is maintained at an approximately right angle relative to the extension arm 1.

[0039] When the aerofoil 2 moves opposite to the aerodynamic lift then the centres of the wheels 3 are 4 at the same side as the aerofoil 2, relative to their axes. At the same time, the toothed wheel 5 is arranged with its major axis perpendicular to the extension arm 1. This arrangement causes that the aerofoil 2 rotates as fast as possible relative to the extension arm 1 in a direction opposite to the direction of the extension arm rotating around the main axis 0.

[0040] Figs. 5 and 5a show an example provided with a Geneva mechanism, here comprised of a main wheel 3, a first wheel 4 and pins 12, the main wheel 3 and the first wheel 4 having mutually corresponding arcuate profiles for holding up rotation of the first wheel, and furthermore the first wheel 4 has gaps 4a to be engaged with the pins 12 to induce rotation of the first wheel 4 in a segment of a turn. A further portion of the gear transmission P in this embodiment is similar to the gear transmission P shown in fig. 4, i.e., it has additional pulleys 6, 7 and belts 13, but as in the remaining examples, this portion of the gear transmission P may be implemented in any other way, by any method known in the art to enable obtaining suitable rotation of the aerofoil 2. Also the Geneva mechanism not necessarily has to be implemented in the form of wheels 3, 4, but this variant will be optimal in terms of the least complexity of the mechanism.

[0041] In this mechanism, wheels 3 and 4 have specifically adapted shapes (arcuate profiles) to produce a similar effect to operation of the mechanism of the embodiment of Figs. 1, 2, 4, 4a.

[0042] When the aerofoil 2 moves in the direction of the aerodynamic lift then the arcuate edge of the wheel 4 slides upon the arcuate edge of the wheel 3. This causes that the wheel 4 is stationary relative to the extension arm 1. Thus, the aerofoil 2 is stationary relative to the extension arm 1.

[0043] When the aerofoil 2 moves in direction opposite to the aerodynamic lift, the gaps 4a in the element 4 overlap the pins 12 to cause rotation of the element 4 in the same direction relative to the extension arm 1, towards which this extension arm rotates around its axis 0. Thus, the aerofoil 2 rotates relative to the extension arm 1 in the direction opposite to the rotation of the extension arm 1 around its axis 0. Clearly, the invention is not limited to the above described embodiments and the features indicated in the claim may be used in any combination proper for a specific use of the solution.

Claims

Claims1. A cycloidal rotor having a main axis (0), extension arms (1) rotatable around the main axis (0) and arranged in a star configuration, and aerofoils (2) rotationally connected to the extension arms (1), wherein the aerofoils (2) are coupled rotationally with the rotation of the extension arms (1) via a gear transmission (P) so that the gear ratio between the rotation of the extension arms (1) and the rotation of the aerofoils (2) is 2: 1, characterized in that the gear transmissions (P) are gear transmissions (P) for inducing variable rotational speed of the aerofoils (2) relative to the rotational speed of the extension arms (1), wherein each of the gear transmissions (P) induces slowed down rotation of the corresponding aerofoil (2) relative to the extension arm (1) when the aerofoil (2) is perpendicular to the extension arm (1), and accelerated rotation of the aerofoil (2) relative to the extension arm (1) when the aerofoil is parallel to the extension arm (1).

2. The rotor according to claim 1 , characterized in that the rotor comprises on the main axis (0) a main gear transmission element (3), rotationally coupled with each of the aerofoils (2) via the gear transmission (P).

3. The rotor according to claim 2, characterized in that the main gear transmission element (3) is independently rotatable on the main axis (0) relative to the extension arms, to cause a change in the thrust direction of the rotor.

4. The rotor according to claim 2, characterized in that the main gear transmission element (3) is a main wheel (3), and each gear transmission (P) comprises: a first wheel (4) coupled counter-rotationally with the main wheel (3), a second wheel (5) coupled counter-rotationally with the first wheel (4), wherein the second wheel (5) is coupled rotationally in a concurrent manner with the aerofoil (2).

5. The rotor according to claim 4, characterized in that the wheels (3, 4, 5) are toothed wheels, wherein the second toothed wheel (5) is coupled rotationally with theaerofoil (2) via a first auxiliary wheel (6) that is coaxial and rotationally coupled therewith, and a second auxiliary wheel (7) coupled via an endless connector (8) with the first auxiliary wheel (6), and coaxial and coupled rotationally with the aerofoil (2).

6. The rotor according to claim 4, characterized in that the wheels (3, 4, 5) are toothed wheels, and the second toothed wheel (5) is coupled rotationally with the aerofoil (2) by means of additional toothed wheel interposed between them.

7. The rotor according to claims 5 or 6, characterized in that one of the first toothed wheel (4) and the main toothed wheel (3) comprises means for holding up rotation of the first toothed wheel (4) for a segment of the turn around the main toothed wheel (3).

8. The rotor according to claim 7, characterized in that the means for preventing the first toothed wheel (4) and the main toothed wheel (3) from coupling comprise a partially toothless profile (10) of the main toothed wheel (3) and sliding means (11) of the first toothed wheel (4).

9. The rotor according to claim 4, characterized in that the wheels (3, 4) are rotational eccentrically and non-circular, while the second wheel (5) has a central rotation axis and is non-circular.

10. The rotor according to claim 9, characterized in that the wheels (3, 4, 5) are elliptical.

11. The rotor according to claim 9, characterized in that the wheels (3, 4, 5) are toothed wheels.

12. The rotor according to claim 2, characterized in that the gear transmission (P) is equipped with a Geneva mechanism.

13. The rotor according to claim 12, characterized in that the Geneva mechanism comprises a main wheel (3), a first wheel (4), and pins (12), wherein the main wheel(3) and the first wheel (4) have mutually corresponding arcuate profiles to couple rotationally the wheels (3, 4), and the first wheel (4) has gaps (4a) to be coupled with the pins (12) to hold up rotation of the first wheel (4) in a segment of the turn.

Images