NL2017463B1 - Cam transmission device for converting input rotary motion into output reciprocating motion, driving device comprising the transmission device, and aerial vehicle comprising wings driven by the driving device - Google Patents
Cam transmission device for converting input rotary motion into output reciprocating motion, driving device comprising the transmission device, and aerial vehicle comprising wings driven by the driving device Download PDFInfo
- Publication number
- NL2017463B1 NL2017463B1 NL2017463A NL2017463A NL2017463B1 NL 2017463 B1 NL2017463 B1 NL 2017463B1 NL 2017463 A NL2017463 A NL 2017463A NL 2017463 A NL2017463 A NL 2017463A NL 2017463 B1 NL2017463 B1 NL 2017463B1
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- Prior art keywords
- cam
- cam slot
- transmission device
- members
- sector
- Prior art date
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- 230000005540 biological transmission Effects 0.000 title claims abstract description 168
- 230000033001 locomotion Effects 0.000 title claims abstract description 62
- 230000008878 coupling Effects 0.000 claims description 69
- 238000010168 coupling process Methods 0.000 claims description 69
- 238000005859 coupling reaction Methods 0.000 claims description 69
- 230000007935 neutral effect Effects 0.000 claims description 21
- 239000000463 material Substances 0.000 description 17
- 230000007246 mechanism Effects 0.000 description 13
- 230000006870 function Effects 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 150000002739 metals Chemical class 0.000 description 3
- 230000001360 synchronised effect Effects 0.000 description 3
- 239000000446 fuel Substances 0.000 description 2
- 230000009347 mechanical transmission Effects 0.000 description 2
- 239000007769 metal material Substances 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
- F16H25/16—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for interconverting rotary motion and oscillating motion
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C33/00—Ornithopters
- B64C33/02—Wings; Actuating mechanisms therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64U—UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
- B64U10/00—Type of UAV
- B64U10/40—Ornithopters
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64U—UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
- B64U10/00—Type of UAV
- B64U10/80—UAVs characterised by their small size, e.g. micro air vehicles [MAV]
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64U—UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
- B64U50/00—Propulsion; Power supply
- B64U50/10—Propulsion
- B64U50/19—Propulsion using electrically powered motors
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64U—UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
- B64U50/00—Propulsion; Power supply
- B64U50/20—Transmission of mechanical power to rotors or propellers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H19/00—Gearings comprising essentially only toothed gears or friction members and not capable of conveying indefinitely-continuing rotary motion
- F16H19/08—Gearings comprising essentially only toothed gears or friction members and not capable of conveying indefinitely-continuing rotary motion for interconverting rotary motion and oscillating motion
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H27/00—Step-by-step mechanisms without freewheel members, e.g. Geneva drives
- F16H27/02—Step-by-step mechanisms without freewheel members, e.g. Geneva drives with at least one reciprocating or oscillating transmission member
Abstract
A transmission device for converting input rotary motion into output reciprocating motion comprises: an input axis; N (N being an integer at least equal to 2, and even) spaced output axes extending parallel to each other and to the input axis; N cam slot members configured to rotate about a respective one of the output axes; and a cam member configured to rotate about the input axis. Each cam slot member comprises a cam slot extending from a cam slot radius radially inwards. The transmission device is constructed and arranged to rotate any one of the cam slot members in opposite direction to a direction of rotation of an adjacent cam slot member, and to align the cam slot of any one of the cam slot members with the cam slot of an adjacent cam slot member at at least one rotational position of said any one of the cam slot members. The cam member comprises at least one cam at a distance from the input axis, and configured to consecutively engage in the cam slots of at least two adjacent cam slot members for reciprocating motion of the cam slot members.
Description
FIELD OF THE INVENTION
The present invention relates to the field of transmission devices for converting input motion into output motion, in particular for converting input rotary motion into output reciprocating motion. The invention also relates to a driving device having a motor delivering input rotary motion, the motor being coupled to the transmission device. The invention also relates to an aerial vehicle comprising the driving device to provide output reciprocating motion to drive wings of the aerial vehicle.
BACKGROUND OF THE INVENTION
Transmission devices which convert a rotary motion, from for example a rotating electric motor, such as a DC motor, into a reciprocating motion are known. These transmission devices often consist of linkage or string-based mechanisms. Although these mechanisms function quite well for normal sized transmission devices, they are not ideal for miniaturized applications. Due to their complex nature, i.e. they consist of a high number of parts and they include moving hinges, they are difficult and thus expensive to manufacture. So, mass production of said mechanisms is cumbersome.
For certain applications it is desirable to have an as small as possible transmission mechanism. The abovementioned linkage and string-based mechanisms have limitations regarding their miniaturization. This is a clear disadvantage for small scale applications. The main reason is the high number of parts necessary.
Some applications require a lightweight transmission mechanism. Again, the complexity and high number of parts necessary for the said transmission mechanisms impose limitations regarding the weight/mass. This is another disadvantage.
One of the possible applications for a transmission device converting rotary into reciprocating motion could be a flapping wing device. An example is the Delfly (http://www.delfly.nl) micro air vehicle, MAV, which has a wingbeat arrangement such that a so-called double clap and fling is realized with four wings. In order to miniaturize micro air
-2 vehicles, the transmission mechanism needs to be as small as possible whilst maintaining a symmetrical, reciprocating motion of the flapping wings.
The flapping mechanism needs to produce a high frequency flapping motion with high amplitude in order to provide enough thrust. At the same time it needs to be lightweight and compact.
The Delfly MAV has wings flapping with a 40° angular amplitude. The wings are driven by a linkage mechanism. The main disadvantage of linkage mechanisms, as mentioned, is their complexity. They consist of many parts and include moving hinges. This limits their further miniaturization and requires high production costs. Another disadvantage is the slightly asymmetrical wing motion inherent to linkage mechanisms. So, a difficulty lies in achieving a high amplitude rocking motion that is, at the same time, symmetric.
Thus there is a need for a transmission device, and driving device including the transmission device, in particular for driving wings of an aerial vehicle, but not limited to such application. The transmission device should have a simple design, that is lightweight, efficient, easy to manufacture and allows miniaturization. Additionally, there is a need for such a transmission device that converts a rotary motion into a high frequency reciprocating motion with a high amplitude that is, at the same time, symmetrical.
SUMMARY OF THE INVENTION
It would be desirable to provide a transmission device, driving device and aerial vehicle having a simple structure. It would also be desirable to provide a transmission device, driving device and aerial vehicle which can be miniaturized. It would also be desirable to provide a transmission device, driving device and aerial vehicle allowing a light weight. It would also be desirable to provide a transmission device, driving device and aerial vehicle having low inertia. It would also be desirable to provide an alternative transmission device, driving device and aerial vehicle.
To better address one or more of these concerns, in a first aspect of the invention a transmission device for converting input rotary motion into output reciprocating motion is provided. The transmission device comprises:
an input axis extending perpendicular to a virtual plane, wherein the input axis intersects the virtual plane at an input axis intersection point;
N (N being an integer at least equal to 2, and even) output axes extending parallel to each other, wherein the output axes are spaced and perpendicular to the virtual plane, and wherein the output axes intersect the virtual plane at respective output axis intersection points;
-3N cam slot members, each being configured to rotate about a respective one of the output axes, each cam slot member comprising a cam slot extending from a cam slot radius radially inwards, wherein the transmission device is constructed and arranged to rotate any one of the cam slot members in opposite direction to a direction of rotation of an adjacent cam slot member, and to align the cam slot of any one of the cam slot members with the cam slot of an adjacent cam slot member at at least one rotational position of said any one of the cam slot members; and a cam member configured to rotate about the input axis, the cam member comprising at least one cam at a distance from the input axis, which at least one cam is configured to consecutively engage in the cam slots of at least two adjacent cam slot members for reciprocating motion of the cam slot members.
The input axis and the output axes define axes of rotation, and may either be virtual axes, or physical axes supported in appropriate bearing structures known as such. In case of virtual axes, the primary and secondary engagement members are supported in appropriate bearing structures known as such to allow for a rotation thereof.
A cam slot member can be made in different shapes and sizes, and can be made from different materials, such as one or more metals and/or plastic materials. For a cam slot member, it is sufficient to comprise the cam slot, as defined above, and functioning as defined above. A remainder of each cam slot member may be arbitrarily shaped and sized, may be made from other materials, or may be even omitted. Hence, this feature contributes to the transmission device having low weight and low inertia. In some embodiments, a cam slot member may be essentially disk-shaped.
A cam member can also be made in different shapes and sizes, and can be made from different materials, such as one or more metals and/or plastic materials. For a cam member, it is sufficient to be configured to engage in the cam slots of the cam slot members to move the cam slot members in a reciprocating motion, while the cam member rotates in one direction.
The at least one cam of the cam member is defined as a part of the cam member configured to engage a surface of a side wall of a cam slot of a cam slot member.
The transmission device according to the invention may be constructed from a low amount of material and components to allow cam slot member and the cam member to be formed, and their function to be performed. Also for this reason, the transmission device may be lightweight, and may have low inertia.
The transmission device according to the invention allows for a high degree of miniaturization.
In the transmission device, in a first phase, when the cam member is rotated in a rotational direction, a cam of the cam member engages a cam slot of a first one of the cam
-4 slot members. During this engagement, the cam member rotates in the rotational direction, and drives and rotates the first one of the cam slot members in an opposite rotational direction. Also during this engagement, a second one of the cam slot members adjacent to the first one of the cam slot members driven by the cam member, is rotated in the rotational direction. Thus, in the first phase of engagement between the cam member and a first one of the cam slot members, the two adjacent first and second ones of the cam slot members rotate in opposite rotational directions.
In a second phase, the cam of the cam member, still rotating in the same rotational direction as before, engages a cam slot of the second one of the cam slot members. During this engagement, the cam member still rotates in the rotational direction, and drives and rotates the second one of the cam slot members in an opposite rotational direction. Also during this engagement, the first one of the cam slot members adjacent to the second one of the cam slot members driven by the cam member, is rotated in rotational direction. Thus, then the two adjacent first and second ones of the cam slot members again rotate in opposite rotational directions, however, both oppositely to the rotational directions in the previous phase.
The angle through which the cam slot member (engaged by the cam member) moves, at a given angle of rotation of the cam member, may depend on the ratio of the distance of the cam relative to the input axis on the one hand, and the cam slot radius of the cam slot member on the other hand.
As indicated above, in the first and second phases, both the first one and the second one of the cam slot members move in reciprocating manner. This makes the transmission device well-suited to actuate one or more pairs of wings of an aerial vehicle, wherein the wing movements are generated by the cam slot members rotating around the output axes, which may function as a virtual or physical hinge axis for the wings. The wings may also be connected, such as fixedly connected, or elastically connected, to the respective cam slot members, e.g. at an end of each wing.
In an embodiment of the transmission device, the cam member comprises at least one pair of diagonally opposed cams.
The use of diagonally opposed cams allows for an efficient, balanced motion input of the transmission device, wherein multiple cam slot members may be driven simultaneously by the same cam member.
In a simple embodiment of the transmission device, the at least one cam comprises a pin having a contact surface, such as a cylindrical contact surface, configured to contact a side surface of each cam slot.
-5The pin is a low-cost, low-weight implementation of a cam, and can have a cylindrical or otherwise rounded surface to engage in a cam slot of a cam slot member.
In an embodiment of the transmission device, the at least one cam comprises a roller having a contact surface, such as a cylindrical contact surface, configured to contact a side surface of each cam slot, the roller being mounted on the cam member to rotate freely about a roller axis parallel to the input axis.
Implementing the cam as a roller as defined above allows for a lowering of friction between the cam and a cam slot side wall surface, since a difference in speed between the roller surface and the cam slot side wall surface, as seen in the direction of the cam slot side wall surface, may be absorbed by a rotation of the roller.
In an embodiment of the transmission device, the at least one cam is fixedly mounted on the cam member.
When the at least one cam is fixedly mounted on the cam member, a simple and effective embodiment is obtained in which a fixed distance between the at least one cam and the input axis exists. In case the at least one cam comprises a pin, the pin may be fixed to a support arm, or be integral with a support arm of the cam member. In case the at least one cam comprises a roller, the roller axis can be fixed to a support arm, or be integral with a support arm of the cam member.
In an embodiment of the transmission device, the at least one cam is mounted on the cam member such that the distance between the at least one cam and the input axis is variable.
The variable distance is in a radial direction relative to the input axis, and may cause the at least one cam to engage a side wall surface of the cam slot at different positions of the side wall surface during the rotation of the at least one cam than the at least one cam would engage the side wall surface of the cam slot in case the at least one cam would be fixed on the cam member. Accordingly, with a cam member rotating at one speed, an angular speed profile, i.e., angular speed as a function of time, of the cam slot member reciprocatingly driven by the cam member may be varied depending on the varying distance between the at least one cam and the input axis.
In an embodiment of the transmission device having a variable distance between the at least one cam and the input axis, the at least one cam is mounted on the cam member to be radially slidable relative to the input axis.
-6In an embodiment, the transmission device further comprises a cam guide for guiding the at least one cam to vary the distance between the at least one cam and the input axis during rotation of the cam member about the input axis.
The cam guide may be stationary, and may engage the at least one cam to move it away from, or to move it towards the input axis, or to keep a constant distance between the at least one cam and the input axis, between different angular positions of the cam member.
In an embodiment of the transmission device, the cam guide is configured to define a minimum distance between the at least one cam and the input axis when the cam slot of a cam slot member faces the input axis. In other positions of the cam slot, the distance between the at least one cam and the input axis is increased in a predefined manner by the cam guide.
As defined above, the transmission device is constructed and arranged to rotate any one of the cam slot members in opposite direction to a direction of rotation of an adjacent cam slot member. In an embodiment of the transmission device, this feature is obtained in that each cam slot member comprises at least one engagement sector of a circular surface having an effective engagement sector radius and a central axis coaxially with the corresponding output axis, and wherein the at least one engagement sector of each one of the cam slot members engages an engagement sector of an adjacent cam slot member.
The engagement sector may extend on one side, or on both sides of the cam slot of the cam slot member. In particular, in some embodiments the cam slot may be centrally located in the engagement sector.
A surface of an engagement sector of a cam slot member is circular, i.e. the surface, as seen in a tangential direction, generally follows (a part of) a circle. In some embodiments, the surface is profiled. In some embodiments, the surface is flat, convex or concave, as seen in cross-sectional view.
A surface of an engagement sector of a cam slot member has an effective engagement sector radius, and a central axis, relative to which the effective engagement sector radius is measured. Herein, the term ‘effective radius’ relates to a radius which is effective in transmission of angular movement in the engagement of an engagement sector of a cam slot member with an engagement sector of an adjacent cam slot member, where the angular speed of the cam slot member depends on the embodiment and relative location of the cam member with respect to the cam slot member.
-7As defined above, the transmission device is constructed and arranged to rotate any one of the cam slot members in opposite direction to a direction of rotation of an adjacent cam slot member. In an embodiment of the transmission device, this feature is obtained in that the transmission device comprises N synchronization members, each being configured to rotate about a respective one of the output axes, each synchronization member comprising at least one coupling sector of a circular surface having an effective coupling sector radius and a central axis coaxially with the corresponding output axis, wherein the at least one coupling sector of each one of the synchronization members engages a coupling sector of an adjacent synchronization member. Advantageously, the cam slot members are fixed to the respective synchronization members, to be rotatable together.
A synchronization member can be made in different shapes and sizes, and can be made from different materials, such as one or more metals and/or plastic materials. For a synchronization member, it is sufficient to comprise the at least one coupling sector, as defined above, and functioning as defined above. A remainder of each synchronization member may be arbitrarily shaped and sized, may be made from other materials, or may be even omitted. Hence, this feature contributes to the transmission device having low weight and low inertia. In some embodiments, a synchronization member may be essentially diskshaped.
A surface of a coupling sector of a synchronization member is circular, i.e. the surface, as seen in a tangential direction, generally follows (a part of) a circle. In some embodiments, the surface is profiled. In some embodiments, the surface is flat, convex or concave, as seen in cross-sectional view.
A surface of a coupling sector of a synchronization member has an effective coupling sector radius, and a central axis, relative to which the effective coupling sector radius is measured. Herein, the term ‘effective radius’ relates to a radius which is effective in transmission of angular movement in the engagement of a coupling sector of a synchronization member with a coupling sector of an adjacent synchronization member.
It is noted that the feature of rotating one of the cam slot members in opposite direction to a direction of rotation of an adjacent cam slot member can be reached by the use of engagement sectors on the cam slot members, or by the use of synchronization members having coupling sectors, or by both features.
In an embodiment of the transmission device, each engagement sector is provided with a series of teeth, and the series of teeth of the at least one engagement sector of each
-8one of the cam slot members engages with the series of teeth of an engagement sector of an adjacent cam slot member.
In an embodiment of the transmission device, each coupling sector is provided with a series of teeth, and the series of teeth of the at least one coupling sector of each one of the synchronization members engages with the series of teeth of a coupling sector of an adjacent synchronization member.
Each tooth of each series of teeth may extend radially and axially relative to the corresponding central axis of the corresponding cam slot member or synchronization member, respectively. An effective radius of a sector provided with teeth is slightly smaller than the distance between the central axis and the tops of the teeth.
In another embodiment of the transmission device, each engagement sector is provided with a friction surface, and the friction surface of the at least one engagement sector of each one of the cam slot members frictionally engages with the friction surface of an engagement sector of an adjacent cam slot member.
In an embodiment of the transmission device, each coupling sector is provided with a friction surface, and the friction surface of the at least one coupling sector of each one of the synchronization members frictionally engages with the friction surface of a coupling sector of an adjacent synchronization member.
In an embodiment of the transmission device, the effective engagement sector radii of the respective cam slot members are the same, whereby a symmetrical and equal (in absolute sense) angular reciprocating movement of the cam slot members can be obtained. For similar reasons, in an embodiment of the transmission device, the effective coupling sector radii of the respective synchronization members are the same.
In a simple embodiment of the transmission device having strong internal mechanical engagement of components, the effective engagement sector radii of the respective cam slot members are the same as the effective coupling sector radii of the respective synchronization members.
In an embodiment of the transmission device, at least one cam slot member is directly or indirectly coupled to a spring member, such as a torque spring member or a linear spring member. The cam slot member may have a neutral angular position in which the spring member does not exert a torque on the cam slot member, and may have at least one biased angular position different from the neutral angular position, in which biased angular position the spring member exerts a torque on the cam slot member driving the cam slot member back to the neutral angular position thereof.
-9The spring member has one part coupled to the cam slot member, and another part coupled to a stationary structure, such as a frame or housing or body of the transmission device, or the device of which the transmission device forms part. The spring member produces a counteracting force/torque on the cam slot member when the cam slot member is rotated away from its neutral angular position in any one of its two opposite rotation directions. A spring characteristic of the spring member is selected such that in a transmission device in operation a desired dynamic behaviour of the cam slot member is obtained, taking into account all mechanical aspects of a mechanical system in which the transmission device is included.
When one cam slot member is coupled to a spring member, the transmission device being constructed and arranged to rotate any one of the cam slot members in opposite direction to a direction of rotation of an adjacent cam slot member, all cam slot members are mechanically coupled to each other, whereby the spring member produces a counteracting force/torque on all cam slot members when they are rotated away from their neutral angular position in any one of their two opposite rotation directions.
In some embodiments of the transmission device, more than one cam slot member is coupled to a respective spring member. In some embodiments of the transmission device, all cam slot members are coupled to respective spring members.
The cam slot members may be coupled to synchronization members or other parts (such as wings) as explained below, such that a (direct) coupling of a spring member to a synchronization member or other part is to be considered as an (indirect) coupling of the spring member to the cam slot member.
The spring member acts as an energy storage element, and thereby may flatten and/or reduce a load of motor driving a transmission device including at least one spring member.
In some embodiments, the spring member is made of metal, such as steel, or plastic. In some embodiments, the spring member is elongated, and is configured to be twisted around its longitudinal axis. In some embodiments, the spring member comprises a wound wire structure.
In an embodiment of the transmission device, the input axis intersection point is at equal distance from all output axis intersection points, and each one of cams, when the cam member is rotated in one direction, is configured to consecutively engage the cam slot of each cam slot member.
This has the advantage of a compact construction of the transmission device, in particular when the input axis intersection point and two output axis intersection points corresponding to adjacent cam slot members define a triangle. When N is at least equal to
- 104, and the output axis intersection points are corner points of an N-sided regular polygon, the input axis intersection point is located centrally in the polygon.
In a second aspect of the present invention, a driving device comprising the transmission device according to the present invention is provided. The driving device further comprises a motor operatively coupled to the cam member of the transmission device for rotating the cam member.
In an embodiment of the driving device, the motor is an electric motor. The electric motor may be powered by a battery, a fuel cell, one or more photovoltaic cells, or any other electric power supply. An electric motor can be controlled adequately by electronic circuitry to provide a speed of rotation of the primary engagement member of the transmission device, e.g. based on locally (i.e. in or near the driving device) or remotely provided control signals, and/or e.g. based on local or remote sensor signals. Control signals may be provided wirelessly to the driving device. On the other hand, also at least one fuel (such as petrol) powered motor can be used in the driving device.
In a third aspect of the present invention, an aerial vehicle is provided. The aerial vehicle may be a micro air vehicle, MAV. The aerial vehicle comprises the driving device according to the present invention. The aerial vehicle further comprises wings driven by the driving device in reciprocating manner.
With the driving device of the present invention, including the transmission device of the present invention, a high amplitude (e.g. 90° angular range) rocking motion of the wings, flapping in a synchronized way, can be obtained. With N = 4, two pairs of wings may be actuated to obtain a clap-and-peel aerodynamic mechanism, which occurs twice per wing beat cycle when adjacent wings approach each other.
In an particular simple embodiment of the aerial vehicle, which may be lightweight and compact, the wings are coupled to the cam slot members and/or to the synchronization members.
These and other aspects of the invention will be more readily appreciated as the same becomes better understood by reference to the following detailed description and considered in connection with the accompanying drawings in which like reference symbols designate like parts.
- 11 BRIEF DESCRIPTION OF THE FIGURES
Figure 1A schematically depicts a front view of a first embodiment of a transmission device according to the invention, in an operational position thereof.
Figure 1B schematically and partly diagrammatically depicts a cross-sectional view of the transmission device of Figure 1A, taken along the line lb, and included in an embodiment of a driving device according to the present invention.
Figures 2A, 2B, 2C and 2D schematically illustrate subsequent operational positions of the transmission device of Figure 1A.
Figure 3A schematically depicts a front view of a second embodiment of a transmission device according to the invention, in an operational position thereof.
Figure 3B schematically and partly diagrammatically depicts a cross-sectional view of the transmission device of Figure 3A, taken along the line lllb, and included in an embodiment of a driving device according to the present invention.
Figure 3C schematically depicts a front view of a variant of the second embodiment of a transmission device according to the invention, in an operational position thereof.
Figure 3D schematically and partly diagrammatically depicts a cross-sectional view of the transmission device of Figure 3C, taken along the line Hid, and included in an embodiment of a driving device according to the present invention.
Figures 4A, 4B, 4C and 4D schematically illustrate subsequent operational positions of the transmission device of Figures 3A and 3B.
Figures 4E, 4F, 4G and 4H schematically illustrate subsequent operational positions of the transmission device of Figures 3C and 3D.
Figure 5 schematically depicts a front view of a third embodiment of a transmission device according to the invention, in an operational position thereof.
Figure 6 schematically depicts a front view of a fourth embodiment of a transmission device according to the invention, in an operational position thereof.
Figure 7A schematically, and in top view, illustrates an embodiment of an aerial vehicle having one pair or two pairs of wings according to the invention, and provided with a motor and transmission device according to the invention.
Figure 7B schematically, and in front view, illustrates an embodiment of the aerial vehicle of Figure 7A having one pair of wings.
Figure 7C schematically, and in front view, illustrates an embodiment of the aerial vehicle of Figure 7A having two pairs of wings.
- 12 DETAILED DESCRIPTION OF THE FIGURES
Figures 1A depicts a front view of an embodiment of a transmission device 100 for converting input rotary motion into output reciprocating motion, and Figure 1B schematically and partly diagrammatically depicts a cross-sectional view of the transmission device 100.
A first cam slot member 102 and a second cam slot member 104 are configured to rotate about a respective one of spaced output axes 106, 108. The first and second cam slot members 102 and 104 each comprise a cam slot 110, 112, respectively, extending from a cam slot radius R1 radially inwards.
A cam member 120 is configured to rotate about an input axis 122. The cam member 120 comprises two cams 124, 126, each at a distance R2 from the input axis 122. The cams 124, 126 are diagonally opposed, and are connected through supports 128 to a cam axis 129 being coaxially with the input axis 122. Each cam 124, 126 is arranged to consecutively engage in the cam slots 110, 112 of the adjacent cam slot members 102, 104 when the cam member 120 is rotated.
Each cam 124, 126 may comprise a pin having a contact surface, such as a cylindrical contact surface, configured to contact an inner surface of each cam slot 110, 112, wherein the pin is fixedly mounted on the respective support 128 of the cam member 120. Alternatively, each cam 124, 126 may comprise a roller having a contact surface, such as a cylindrical contact surface, configured to contact an inner surface of each cam slot 110, 112, wherein the roller is mounted on the respective support 128 of the cam member 120 such that it rotates freely (idler roller) about a roller axis parallel to the input axis 122.
If the plane of drawing of Figure 1A is considered to be a virtual plane, the input axis 122 extends perpendicular to this virtual plane, wherein the input axis 122 intersects the virtual plane at an input axis intersection point. Also the output axes 106, 108 are perpendicular to the virtual plane, and they intersect the virtual plan at respective output axis intersection points. As can be seen in Figure 1 A, the input axis intersection point of the input axis 122 and the output axis intersection point of the output axes 106, 108 form a symmetrical triangle.
The transmission device 100 is constructed and arranged to synchronously rotate any one of the cam slot members 102, 104 in opposite direction to a direction of rotation of an adjacent cam slot member 104, 102, and to align the cam slot 110, 112 of any one of the cam slot members 102, 104 with the cam slot 112, 110 of an adjacent cam slot member 104, 102 at at least one rotational position of said any one of the cam slot members 102,
104.
In a first embodiment of this synchronizing feature, each cam slot member 102, 104 comprises an engagement sector of a circular surface having an effective engagement
- 13sector radius R1 and a central axis coaxially with the corresponding output axis 106, 108. The effective engagement sector radii R1 of the respective cam slot members 102, 104 are the same. The engagement sector of each one of the cam slot members 102, 104 engages an engagement sector of an adjacent cam slot member 104, 102. In Figure 1A, the engagement sector of cam slot member 102 is from about the lowermost point of its circumference to about the rightmost point of its circumference, while the engagement sector of cam slot member 104 is from about the lowermost point of its circumference to about the leftmost point of its circumference. Hence, the engagement sectors have an angular extension of about 90° (taking into account a width of the slots 110, 112). Each engagement sector may be provided with a series of teeth, wherein the series of teeth of the engagement sector of each one of the cam slot members 102, 104 engages with the series of teeth of an engagement sector of an adjacent cam slot member 104, 102. Alternatively, each engagement sector may be provided with a friction surface, wherein the friction surface of the engagement sector of each one of the cam slot members 102, 104 frictionally engages with the friction surface of an engagement sector of an adjacent cam slot member 104, 102.
In a second embodiment of said synchronizing feature, the transmission device 100 comprises two synchronization members 130, each being configured to rotate about a respective one of the output axes 106, 108. Each cam slot member 102, 104 is fixed to a respective synchronization member 130 to rotate together. Since such synchronization members 130 are optional, they are depicted in dashed lines. Each synchronization member 130 comprises at least one coupling sector of a circular surface having an effective coupling sector radius R1 and a central axis coaxially with the corresponding output axis 106, 108. The effective coupling sector radii R1 of the respective synchronization members 130 are the same. The coupling sector of each one of the synchronization members 130 engages a coupling sector of an adjacent synchronization member 130. The coupling sectors have an angular extension of essentially 90°. Each coupling sector may be provided with a series of teeth, wherein the series of teeth of the coupling sector of each one of the synchronization members 130 engages with the series of teeth of a coupling sector of an adjacent synchronization member 130. Alternatively, each coupling sector may be provided with a friction surface, wherein the friction surface of the coupling sector of each one of the synchronization members 130 frictionally engages with the friction surface of a coupling sector of an adjacent synchronization member 130.
The first embodiment of the synchronizing feature may be combined with the second embodiment of the synchronizing feature. In this case, the effective engagement sector radii of the respective cam slot members 102, 104 may be the same as the effective coupling sector radii of the respective synchronization members 130. Alternatively, only one of the
- 14 first embodiment and the second embodiment of the synchronizing feature may be implemented in the transmission device 100. In case only the second embodiment of the synchronizing feature is implemented, the cam slot members 102, 104 need not be provided with engagement sectors, and in some embodiments the cam slot radius may be substantially the same or slightly smaller than the effective coupling sector radius.
In Figures 1A and 1B, the cam slot members 102, 104 and the synchronization members 130 are depicted as essentially cylindrically shaped. For a cam slot member 102, 104, it is sufficient to comprise a cam slot 110, 112 and at least one engagement sector as defined above and functioning as defined above (as a first embodiment of the synchronizing feature). For a synchronization member 130, it is sufficient to comprise at least one coupling sector as defined above and functioning as defined above (as a second embodiment of the synchronizing feature). A remainder of each cam slot member 102, 104 or synchronization member 130 may be arbitrarily shaped and sized, may be made from different materials, or may be even omitted, apart from a portion of a cam slot member 102, 104 defining the cam slot 110, 112 thereof.
The cam slot members 102, 104 and the synchronization members 130 can thus be made in different shapes and sizes. They further can be made from different materials, such as one or more metal materials, one or more plastic materials, and combinations thereof. The materials should be capable of withstanding dynamic loads.
A surface of an engagement sector or a synchronization sector is circular, i.e. the surface, as seen in a tangential direction, generally follows (a part of) a circle. In some embodiments, the surface is profiled, such as provided with a series of teeth. In some embodiments, the surface is flat, convex or concave, as seen in cross-section in axial direction.
The cam member 120 may be driven through axis 128 by a motor 140 in a direction of rotation indicated by arrow 142. The motor 140 may be coupled (directly through a physical connection 128, or through a transmission or gear) to the cam member 120.
The combination of the transmission device 100 and the motor 140 forms a driving device.
The operation of the transmission device 100, while driving the cam member 120, is illustrated in Figures 2A, 2B, 2C and 2D.
Starting from the angular position of the cam member 120 shown in Figure 2A, and rotating the cam member 120 in the direction of rotation as indicated by arrow 142 (counterclockwise) around input axis 122, the first cam 124 will move into first cam slot 110 of the first cam slot member 102, while the second cam 126 will move away from second cam slot 112 of the second cam slot member 104. As a result, the first cam slot member 102 will be driven by the cam member 120 to rotate clockwise around output axis 106 and, due to the
- 15synchronization feature of the transmission device 100, the second cam slot member 104 will be driven to rotate counter-clockwise around output axis 108.
After a rotation of the cam member 120 form the angular position as shown in Figure 2A, across an angle of about 45° in the direction of rotation as indicated by arrow 142 around input axis 122, the angular position of the cam member 120 is as shown in Figure 2B. The first cam 124 has fully moved into the first cam slot 110. While continuing to rotate the cam member 120 in the direction of rotation as indicated by arrow 142, the first cam 124 will drive the first cam slot member 102 further to rotate clockwise and, due to the synchronization feature of the transmission device 100, the second cam slot member 104 will be further driven to rotate counter-clockwise.
After a further rotation of the cam member 120 from the angular position as shown in Figure 2B, across an angle of about 45° in the direction of rotation as indicated by arrow 142 around input axis 122, the angular position of the cam member 120 is as shown in Figure 2C. The first cam 124 is moving out of the first cam slot 110, and into the second cam slot 112. While continuing to rotate the cam member 120 in the direction of rotation as indicated by arrow 142, the first cam 124 will drive the second cam slot member 104 to rotate clockwise and, due to the synchronization feature of the transmission device 100, the first cam slot member 102 will be driven to rotate counter-clockwise.
After a further rotation of the cam member 120 from the angular position as shown in Figure 2C, across an angle of about 45° in the direction of rotation as indicated by arrow 142 around input axis 122, the angular position of the cam member 120 is as shown in Figure 2D. the first cam 124 has fully moved into the second cam slot 112. While continuing to rotate the cam member 120 in the direction of rotation as indicated by arrow 142, the first cam 124 will drive the second cam slot member 104 further to rotate clockwise and, due to the synchronization feature of the transmission device 100, the first cam slot member 102 will b e further driven to rotate counter-clockwise.
After a further rotation of the cam member 120 from the angular position as shown in Figure 2D, across and angle of about 45° in the direction of rotation as indicated by arrow 142 around input axis 122, the angular position of the cam member 120 is again as shown in Figure 2A, albeit that the first cam 124 now takes the position of the second cam 126, and the second cam 126 now takes the position of the first cam 124, as a result of the cam member 120 having rotated across 180°. During the rotation of the cam member 120 across 180°, the first cam slot member 102 and the second cam slot member 104 have made a reciprocating (back and forth) movement across 90°, in opposite rotational directions. Thus, a rotary motion at the input axis 122 of the cam member 120 is converted in the transmission device 100 into a synchronized reciprocating motion of the cam slot members 102, 104, and possibly also of the synchronization members, if present.
- 16As indicated in Figures 1A, 1B, 2A, 2B, 2C and 2D, each one of the cam slot members 102, 104 may have a respective wing 152, 154 (only schematically indicated) coupled to it. If present, the synchronization members 130 may also have a respective wing 152, 154 coupled to it, since they perform the same reciprocating motion as the cam slot members 102, 104. Thus, the motor 140, driving the cam member 120 to rotate in one direction, drives the wings 152, 154 in opposite reciprocating movement.
The wings 152, 154 may physically connected to the cam slot members 102, 104 and/or the synchronization members 130 through a physical connection, in particular a direct physical connection. However, indirect couplings are also possible, e.g. through a mechanical transmission or linkage. The combination of motor 140, transmission 100 and wings 152, 154 may be part of an aerial vehicle having the wings 152, 154 flapping to fly the aerial vehicle.
Above, the operation of the transmission device 100 has been described fora direction of rotation of the cam member 120 as indicated by arrow 142. A similar operation will be reached by rotating the cam member 120 opposite to the direction of rotation as indicated by arrow 142.
A spring member 160, such as a torque spring member, may be coupled (directly through a physical connection 162, or through a transmission or gear) to one of the first and second cam slot members 102, 104, or to each of the first and second cam slot members 102, 104, or to one of the synchronization members 130, or to each of the synchronization members 130, whereby the first and second cam slot members 102, 104 have a neutral angular position in which the spring member 160 does not exert a torque/force on the first and second cam slot members 102, 104, and at least one biased angular position different from the neutral angular position, in which biased angular position the spring member 160 exerts a torque/force on the first and second cam slot members 102, 104 driving the first and second cam slot members 102, 104 back to the neutral angular position thereof.
In Figures 2A and 2C, biased angular positions of the first and second cam slot members 102, 104 are shown, whereas a neutral angular position of the first and second cam slot members 102, 104 is centrally between said biased angular positions according to Figures 2B and 2D.
Each spring member 160 has one part coupled to the cam slot member(s) 102, 104, and another part coupled to a stationary structure, such as a frame or housing of the transmission device 100. The spring member 160 may produce a counteracting force/torque on the cam slot members 102, 104 when they are rotated away from their neutral angular position in any one of their two opposite rotation directions. A spring characteristic of the spring member 160 is selected such that in a transmission device 100 in operation a desired dynamic behaviour of the cam slot members 102, 104 is obtained, taking into account all
- 17 mechanical aspects of a mechanical system in which the transmission device 100 is included.
Instead of, or in addition to the spring member 160, at least one spring member, such as a linear spring member, may be coupled between at least one of the wings 152, 154 and a body of the aerial vehicle. Furthermore, at least one spring member may be coupled between the wings 152, 154.
Figure 3A depicts a front view of an embodiment of a transmission device 300 for converting input rotary motion into output reciprocating motion, and Figure 3B schematically and partly diagrammatically depicts a cross-sectional view of the transmission device 300.
A first cam slot member 302, a second cam slot member 303, a third cam slot member 304 and a fourth cam slot member 305 are configured to rotate about a respective one of spaced output axes 306, 307, 308, 309. The first, second, third and fourth cam slot members 302 to 305 each comprise a cam slot 310, 311, 312 and 313, respectively, extending from a cam slot radius R1 radially inwards.
A cam member 320 is configured to rotate about an input axis 322. The cam member 320 comprises one cam 324 at a distance R2 from the input axis 322. The cam 324 is connected through support 328 to a cam axis 329 being coaxially with the input axis 322. The cam 324 is arranged to consecutively engage in the cam slots 310, 311,312, 313 of the adjacent cam slot members 302, 303, 304, 305 when the cam member 320 is rotated.
The cam 324 may comprise a pin having a contact surface, such as a cylindrical contact surface, configured to contact an inner surface of each cam slot 310, 311,312, 313, wherein the pin is fixedly mounted on the support 328 of the cam member 320. Alternatively, the cam 324 may comprise a roller having a contact surface, such as a cylindrical contact surface, configured to contact an inner surface of each cam slot 310, 311, 312, 313, wherein the roller is mounted on the support 328 of the cam member 320 such that it rotates freely (idler roller) about a roller axis parallel to the input axis 322.
If the plane of drawing of Figure 3A is considered to be a virtual plane, the input axis 322 extends perpendicular to this virtual plane, wherein the input axis 322 intersects the virtual plane at an input axis intersection point. Also the output axes 306, 307, 308, 309 are perpendicular to the virtual plane, and they intersect the virtual plan at respective output axis intersection points. As can be seen in Figure 3A, the output axis intersection points of the output axes 306, 307, 308, 309 form a square with the input axis intersection point of the input axis 322 in the middle. The output axis intersection points of the output axes 306, 307 and the input axis intersection point of the input axis 322 form a symmetrical triangle. Likewise, the output axis intersection points of the output axes 307, 308 and the input axis intersection point of the input axis 322 form a symmetrical triangle. Likewise, the output axis
- 18intersection points of the output axes 308, 309 and the input axis intersection point of the input axis 322 form a symmetrical triangle. Likewise, the output axis intersection points of the output axes 309, 306 and the input axis intersection point of the input axis 322 form a symmetrical triangle.
The transmission device 300 is constructed and arranged to synchronously rotate any one of the cam slot members 302, 303, 304, 305 in opposite direction to a direction of rotation of an adjacent cam slot member 302, 303, 304, 305, and to align the cam slot 310, 311,312, 313 of any one of the cam slot members 302, 303, 304, 305 with the cam slot 310, 311,312, 313 of an adjacent cam slot member 302, 303, 304, 305 at at least one rotational position of said any one of the cam slot members 302, 303, 304, 305.
In a first embodiment of this synchronizing feature, each cam slot member 302, 303,
304, 305 comprises an engagement sector of a circular surface having an effective engagement sector radius R1 and a central axis coaxially with the corresponding output axis 306, 307, 308, 309. The effective engagement sector radii R1 of the respective cam slot members 302, 303, 304, 305 are the same. The engagement sector of each one of the cam slot members 302, 303, 304, 305 engages an engagement sector of an adjacent cam slot member 302, 303, 304, 305. In Figure 3A, the engagement sector of each one of the cam slot members 302, 303, 304, 305 is from about the lowermost point of its circumference to about the uppermost point of its circumference. Hence, the engagement sectors have an angular extension of about 180°. Each engagement sector may be provided with a series of teeth, wherein the series of teeth of the engagement sector of each one of the cam slot members 302, 303, 304, 305 engages with the series of teeth of an engagement sector of an adjacent cam slot member 302, 303, 304, 305. Alternatively, each engagement sector may be provided with a friction surface, wherein the friction surface of the engagement sector of each one of the cam slot members 302, 303, 304, 305 frictionally engages with the friction surface of an engagement sector of an adjacent cam slot member 302, 303, 304,
305.
In a second embodiment of said synchronizing feature, the transmission device 300 comprises four synchronization members 330, each being configured to rotate about a respective one of the output axes 306, 307, 308, 309. Each cam slot member 302, 303, 304, 305 is fixed to a respective synchronization member 330 to rotate together. Since such synchronization members 330 are optional, they are depicted in dashed lines. Each synchronization member 330 comprises two coupling sectors of a circular surface having an effective coupling sector radius R1 and a central axis coaxially with the corresponding output axis 306, 307, 308, 309. The two coupling sectors may be formed as one contiguous coupling sector. The effective coupling sector radii R1 of the respective synchronization members 330 are the same. In this embodiment, each synchronization member 330
- 19comprises two coupling sectors, since each synchronization member 330 has two different adjacent other synchronization members 330. The coupling sectors of each one of the synchronization members 330 engage the coupling sectors of adjacent synchronization members 330. The coupling sectors have an angular extension of about 90°. The coupling sectors may be in the same axial position and may form one contiguous coupling sector of 180°, or may be in different axial positions. Each coupling sector may be provided with a series of teeth, wherein the series of teeth of the coupling sectors of each one of the synchronization members 330 engages with the series of teeth of a coupling sector of adjacent synchronization members 330. Alternatively, each coupling sector may be provided with a friction surface, wherein the friction surfaces of the coupling sectors of each one of the synchronization members 330 frictionally engage with the friction surface of a coupling sector of adjacent synchronization members 330.
The first embodiment of the synchronizing feature may be combined with the second embodiment of the synchronizing feature. In this case, the effective engagement sector radii of the respective cam slot members 302, 303, 304, 305 may be the same as the effective coupling sector radii of the respective synchronization members 330. Alternatively, only one of the first embodiment and the second embodiment of the synchronizing feature may be implemented in the transmission device 300. In case only the second embodiment of the synchronizing feature is implemented, the cam slot members 302, 303, 304, 305 need not be provided with engagement sectors, and in some embodiments the cam slot radius may be smaller than the effective coupling sector radius.
In Figures 3A and 3B, the cam slot members 302, 303, 304, 305 and the synchronization members 330 are depicted as essentially cylindrically shaped. For a cam slot member 302, 303, 304, 305, it is sufficient to comprise a cam slot 310, 311,312, 313 and at least one engagement sector as defined above and functioning as defined above (as a first embodiment of the synchronizing feature). For a synchronization member 330, it is sufficient to comprise two coupling sectors as defined above and functioning as defined above (as a second embodiment of the synchronizing feature). A remainder of each cam slot member 302, 303, 304, 305 or synchronization member 330 may be arbitrarily shaped and sized (although within a cam slot radius R1), may be made from different materials, or may be even omitted, apart from a portion of a cam slot member 302, 303, 304, 305 defining the cam slot 310, 311,312, 313 thereof.
The cam slot members 302, 303, 304, 305 and the synchronization members 330, and also the cam member 320, can thus be made in different shapes and sizes. They further can be made from different materials, such as one or more metal materials, one or more plastic materials, and combinations thereof. The materials should be capable of withstanding dynamic loads.
-20A surface of an engagement sector or a synchronization sector is circular, i.e. the surface, as seen in a tangential direction, generally follows (a part of) a circle. In some embodiments, the surface is profiled, such as provided with a series of teeth. In some embodiments, the surface is flat, convex or concave.
The cam member 320 may be driven through axis 329 by a motor 340 in a direction of rotation indicated by arrow 342. The motor 340 may be coupled (directly through a physical connection 329, or through a transmission or gear) to the cam member 320.
The combination of the transmission device 300 and the motor 340 forms a driving device.
The operation of the transmission device 300, while the cam member 320 is driven, is illustrated in Figures 4A, 4B, 4C and 4D.
Starting from the angular position of the cam member 320 shown in Figure 4A, and rotating the cam member 320 in the direction of rotation as indicated by arrow 342 (counterclockwise) around input axis 322, the cam 324 will move into second cam slot 311 of the second cam slot member 303. As a result, the second cam slot member 303 will be driven by the cam member 320 to rotate clockwise around output axis 307 and, due to the synchronization feature of the transmission device 300, the first cam slot member 302 and the fourth cam slot member 305 will be driven to rotate counter-clockwise around respective output axes 306, 309. The third cam slot member 304 will be driven to rotate clockwise around the output axis 308.
After a rotation of the cam member 320 from the angular position as shown in Figure 4A, across an angle of about 45° in the direction of rotation as indicated by arrow 342 around input axis 322, the angular position of the cam member 320 is as shown in Figure 4B. The cam 324 has fully moved into the second cam slot 311. While continuing to rotate the cam member 320 in the direction of rotation as indicated by arrow 342, the cam 324 will drive the second cam slot member 303 further to rotate clockwise and, due to the synchronization feature of the transmission device 300, the first cam slot member 302 and the fourth cam slot member 305 will be further driven to rotate counter-clockwise, while the third cam slot member 304 will be driven further to rotate clockwise.
After a further rotation of the cam member 120 from the angular position as shown in Figure 4B, across an angle of about 45° in the direction of rotation as indicated by arrow 342 around input axis 322, the angular position of the cam member 320 is as shown in Figure 4C. The cam 324 is moving out of the second cam slot 311, and into the first cam slot 310. While continuing to rotate the cam member 320 in the direction of rotation as indicated by arrow 342, the cam 324 will drive the first cam slot member 302 to rotate clockwise and, due to the synchronization feature of the transmission device 300, the second cam slot member
-21 303 and the third cam slot member 304 will be driven to rotate counter-clockwise, while the fourth cam slot member 305 will be driven to rotate clockwise.
After a further rotation of the cam member 320 from the angular position as shown in Figure 4C, across an angle of about 45° in the direction of rotation as indicated by arrow 342 around input axis 322, the angular position of the cam member 320 is as shown in Figure 4D. The cam 324 has fully moved into the first cam slot 310. While continuing to rotate the cam member 320 in the direction of rotation as indicated by arrow 342, the cam 324 will drive the first second cam slot member 302 further to rotate clockwise and, due to the synchronization feature of the transmission device 100, the second cam slot members 303 and the third cam slot member 304 will be further driven to rotate counter-clockwise, while the fourth cam slot member 305 will be further driven to rotate clockwise.
After a further rotation of the cam member 320 from the angular position as shown in Figure 4D, across an angle of about 45° in the direction of rotation as indicated by arrow 342 around input axis 322, the angular position of the cam member 320 is diagonally opposite to the angular position shown in Figure 4A, as a result of the cam member 320 having rotated across 180°. During the rotation of the cam member 320 across 180°, the first, second, third and fourth cam slot members 302, 303, 304, 305 have made a reciprocating (back and forth) movement across 90°, in opposite rotational directions. Thus, a rotary motion at the input axis 322 of the cam member 320 is converted in the transmission device 300 into a synchronized reciprocating motion of the cam slot members 302, 303, 304, 305, and possibly also of the synchronization members 330, if present.
Further rotating the cam member 320 from the angular position as shown in Figure 4D will move the cam 324 subsequently into and out of third cam slot 312 of third cam slot member 304, and into and out of fourth cam slot 313 of fourth cam slot member 305, to arrive again in the position as shown in Figure 4A.
As indicated in Figures 3A, 3B, 4A, 4B, 4C and 4D, each one of the cam slot members 302, 303, 304, 305 may have a respective wing 352, 353, 354, 355 (only schematically indicated) coupled to it. If present, the synchronization members 330 may also have a respective wing 352, 353, 354, 355 coupled to it, since they perform the same reciprocating motion as the cam slot members 302, 303, 304, 305. Thus, the motor 340, driving the cam member 320 to rotate in one direction, drives the wings 352, 353, 354, 355 in opposite reciprocating movement.
The wings 352, 353, 354, 355 may physically connected to the cam slot members 302, 303, 304, 305 and/or the synchronization members 330 through a physical connection, in particular a direct physical connection. However, indirect couplings are also possible, e.g. through a mechanical transmission or linkage. The combination of motor 340, transmission
-22 300 and wings 352, 353, 354, 355 may be part of an aerial vehicle having the wings 352, 353, 354, 355 flapping to fly the aerial vehicle.
Above, the operation of the transmission device 300 has been described for a direction of rotation of the cam member 320 as indicated by arrow 342. A similar operation will be reached by rotating the cam member 320 opposite to the direction of rotation as indicated by arrow 342.
A spring member 360, such as a torque spring member, may be coupled (directly through a physical connection 162, or through a transmission or gear) to one of the first, second, third and fourth cam slot members 302, 303, 304, 305, or to each of the first and second cam slot members 302, 303, 304, 305, or to one of the synchronization members 330, or to each of the synchronization members 330, whereby the cam slot members 302, 303, 304, 305 have a neutral angular position in which the spring member(s) 360 does/do not exert a torque/force on the cam slot members 302, 303, 304, 305, and at least one biased angular position different from the neutral angular position, in which biased angular position the spring member(s) 160 exert(s) a torque/force on the cam slot members 302,
303, 304, 305 driving the cam slot members 302, 303, 304, 305 back to the neutral angular position thereof.
In Figures 4A and 4C, biased angular positions of the cam slot members 302, 303,
304, 305 are shown, whereas a neutral angular position of the cam slot members 302, 303, 304, 305 is centrally between said biased angular positions according to Figures 4B and 4D.
Each spring member 360 has one part coupled to one of the cam slot members 302, 303, 304, 305, and another part coupled to a stationary structure, such as a frame or housing of the transmission device 300. The spring member 360 produces a counteracting force/torque on the cam slot members 302, 303, 304, 305 when they are rotated away from their neutral angular position in any one of their two opposite rotation directions. A spring characteristic of the spring member 360 is selected such that in a transmission device 300 in operation a desired dynamic behaviour of the cam slot members 302, 303, 304, 305 is obtained, taking into account all mechanical aspects of a mechanical system in which the transmission device 300 is included.
Instead of, or in addition to the spring member 360, at least one spring member, such as a linear spring member, may be coupled between at least one of the wings 152, 154 and a body of the aerial vehicle. Furthermore, at least one spring member may be coupled between the wings 152, 154.
Figures 3C, 3D, 4E, 4F, 4G and 4H depict a variant of the transmission device or driving device according to the embodiment of Figures 3A, 3B, 4A, 4B, 4C and 4D explained above. The structure and operation of the transmission device or driving device of Figures
-233C, 3D, 4E, 4F, 4G and 4H essentially is the same as the structure and operation of the embodiment of Figues 3A, 3B, 4A, 4B, 4C and 4D, except that in the variant embodiment the cam is mounted on the cam member 320 such that the distance between the cam 324 and the input axis 322 is variable, whereby the variable distance is in a radial direction relative to the input axis 322. In an embodiment, the cam 324 is radially slidable relative to the input axis 322 through a cam slide member 380.
The transmission device 300 further comprises a cam guide 370 for guiding the cam 324 to vary the distance between the cam 324 and the input axis 322 during rotation of the cam member 320 about the input axis 322. The cam guide 370 comprises a guide path 372 defined by an inner guide wall 374 and an outer guide wall 376. In the embodiment shown, the guide path 372 has a square shape. However, various other closed paths, such as curved paths, are possible. Depending on the shape of the guide path 372, with the cam member 320 rotating at one speed, an angular speed profile (i.e., speed as a function of time) of the cam slot members 302, 303, 304, 305 reciprocatingly driven by the cam member 320 may be varied depending on the varying distance between the cam 324 and the input axis 322 as determined by the shape of the guide path 372. With the square shape of the guide path 372, an essentially triangular angular speed profile of the cam slot members 302, 303, 304, 305 is obtained.
The cam guide 370 is mounted stationary, and engages the cam 324 to move it away from, or to move it towards the input axis 322, or to keep a constant distance between the cam 324 and the input axis 322, between different angular positions of the cam member 320.
As can be seen in Figures 4F and 4H, the cam guide 370 is configured to define a minimum distance between the cam 324 and the input axis 322 when the cam slot 311,310, respectively, of the cam slot member 303, 302, respectively, faces the input axis 322. In other positions of the cam slots 310, 311, 312, 313, the distance between the cam 324 and the input axis 322 is increased in a predefined manner by the cam guide 370.
It is noted that the cam having a variable distance to the input axis, such as actuated by a cam guide as illustrated in Figures 3C, 3D, 4E, 4F, 4G and 4H can also be applied in the other embodiments discussed in this specification, to obtain a specific angular speed profile of reciprocating motion of the cam slot members.
Figure 5 schematically depicts a front view of an embodiment of a transmission device 500 for converting input rotary motion into output reciprocating motion. As can be seen when comparing Figure 5 to Figure 1A, an upper part of the transmission device 500 may be constructed and arranged identical to the transmission device 100. In the transmission device of Figure 5, parts that are similar to parts shown in Figure 1A are
-24 indicated with the same reference sign. For a description of these parts and their functioning, reference is made to the description of Figures 1A, 1B, 2A, 2B, 2C and 2D above.
The transmission device 500 further comprises third, fourth, fifth and sixth members
503. 504, 505, 506. Each one of the members is configured to rotate about respective output axes 513, 514, 515, 516. The third member 503 engages the first cam slot member 102 or a synchronization member 130 coupled thereto, and/or engages the fourth member
504. The fourth member 504 engages the second cam slot member 104 or a synchronization member 130 coupled thereto, and/or engages the third member 503. The fifth member 505 engages the third member 503, and/or engages the sixth member 506.
The sixth member 506 engages the fourth member 504, and/or engages the fifth member
505. The engagement between the first and second cam slot members 102, 104 or their corresponding synchronization members 130 on the one hand, and the third, fourth, fifth and sixth members 503, 504, 505, 506 on the other hand, may be through engagement sectors similar as the cam slot member sectors or the coupling sectors as described above, i.e. using interengaging series of teeth, or using friction surfaces.
Upon rotating of the cam member 120, the transmission device 500 operates to provide a reciprocating motion to the cam slot members 102, 104, and the third, fourth, fifth and sixth members 503, 504, 505, 506. At a rotation of the first cam slot member 102 in clockwise direction, the fourth member 504 and the fifth member 505 will also rotate in clockwise direction, while the second cam slot member 104, the third member 503 and the sixth member 506 will rotate counter-clockwise across the same (absolute) angle, and vice versa.
If only the third and fourth members 503, 504 would be present, and the fifth and sixth members 505, 506 would be absent, then the transmission device is suitable to convert a rotary input motion of the cam member 120 into reciprocating motion of the first and second cam slot members 102, 104 and the third and fourth members 503, 504, to drive four wings of an aerial vehicle, for example.
If the third, fourth, fifth and sixth members 503, 504, 505, 506 are present, then the transmission device is suitable to convert a rotary input motion of the cam member 120 into reciprocating motion of the first and second cam slot members 102, 104 and the third, fourth, fifth and sixth members 503, 504, 505, 506, to drive a maximum of six wings of an aerial vehicle, for example, in the same manner as illustrated above.
Figure 6 schematically depicts a front view of an embodiment of a transmission device 600 for converting input rotary motion into output reciprocating motion.
-25The transmission device 600 comprises eight cam slot members 601,602, 603, 604,
605, 606, 607, 608, rotatable around respective output axes 611,612, 613, 614, 615, 616, 617, 618, and having respective cam slots 621,622, 623, 624, 625, 626, 627, 628. A cam member 630 is rotatable around input axis 632, and comprises four cams 641,642, 643,
644 mounted on supports 645. Each one of the cam slot members 601,602, 603, 604, 605,
606, 607, 608 may be coupled to a synchronization member, as explained above. Shapes and sizes and features of the cam slot members 601,602, 603, 604, 605, 606, 607, 608, the synchronization members, and the cams 641,642, 643, 644 may be as explained above, in particular with respect to Figures 3A, 3B, 4A, 4B, 4C, 4D.
In the transmission device 600, the cam slot members 601,602, 603, 604, 605, 606,
607, 608, upon rotation of the cam member 630, are rotated in reciprocating motion across an angular range of 135°. Each one of the cams 641,642, 643, 644 subsequently moves into and out of cam slots 621,622, 623, 624, 625, 626, 627, 628, 621,622, ..., or in a reverse order, depending on a direction of rotation of the cam member 630.
Figures 7A, 7B and 7C schematically illustrate an aerial vehicle 710 comprising a body 711, and a transmission device 712 coupled to an electric of fuel-powered motor 714, which in turn is coupled to a battery 716 to power the motor 714. The aerial vehicle 710 may have two wings 720, 722 (Figure 7B), or may have four wings 720, 722, 724 and 726 (Figure 7C) coupled to the transmission device 712, whereby the wings 720, 722, 724 and 726 may be driven in reciprocating motion as illustrated by double arrows 728.
If, according to Figure 7B, the aerial vehicle 710 has two wings 720 and 722, the transmission device 712 may e.g. be a transmission device of the present invention as illustrated in Figures 1A, 1B, 2A, 2B, 2C and 2D, in combination with the motor 714 forming a driving device of the present invention.
If, according to Figure 7C, the aerial vehicle 710 has four wings 720, 722, 724 and 726, the transmission device 712 may e.g. be a transmission device of the present invention as illustrated in Figures 3A, 3B, 4A, 4B, 4C and 4D, in combination with the motor 714 forming a driving device of the present invention.
As explained above, a transmission device for converting input rotary motion into output reciprocating motion comprises: an input axis; N (N being an integer at least equal to 2, and even) spaced output axes extending parallel to each other and to the input axis; N cam slot members configured to rotate about a respective one of the output axes; and a cam member configured to rotate about the input axis. Each cam slot member comprises a cam slot extending from a cam slot radius radially inwards. The transmission device is constructed and arranged to rotate any one of the cam slot members in opposite direction to
-26a direction of rotation of an adjacent cam slot member, and to align the cam slot of any one of the cam slot members with the cam slot of an adjacent cam slot member at at least one rotational position of said any one of the cam slot members. The cam member comprises at least one cam at a distance from the input axis, and configured to consecutively engage in the cam slots of at least two adjacent cam slot members for reciprocating motion of the cam slot members.
As required, detailed embodiments of the present invention are disclosed herein. However, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting, but rather, to provide an understandable description of the invention.
The terms a/an, as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising (i.e., open language, not excluding other elements or steps). Any reference signs in the claims should not be construed as limiting the scope of the claims or the invention.
The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
The term coupled, as used herein, is defined as connected, although not necessarily directly.
Claims (28)
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2017463A NL2017463B1 (en) | 2016-09-15 | 2016-09-15 | Cam transmission device for converting input rotary motion into output reciprocating motion, driving device comprising the transmission device, and aerial vehicle comprising wings driven by the driving device |
| PCT/NL2017/050598 WO2018052288A1 (en) | 2016-09-15 | 2017-09-12 | Cam transmission device for converting input rotary motion into output oscillating motion, driving device comprising the transmission device, and aerial vehicle comprising wings driven by the driving device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2017463A NL2017463B1 (en) | 2016-09-15 | 2016-09-15 | Cam transmission device for converting input rotary motion into output reciprocating motion, driving device comprising the transmission device, and aerial vehicle comprising wings driven by the driving device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| NL2017463B1 true NL2017463B1 (en) | 2018-03-22 |
Family
ID=57227045
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NL2017463A NL2017463B1 (en) | 2016-09-15 | 2016-09-15 | Cam transmission device for converting input rotary motion into output reciprocating motion, driving device comprising the transmission device, and aerial vehicle comprising wings driven by the driving device |
Country Status (2)
| Country | Link |
|---|---|
| NL (1) | NL2017463B1 (en) |
| WO (1) | WO2018052288A1 (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0599370A1 (en) * | 1992-11-18 | 1994-06-01 | Koninklijke Philips Electronics N.V. | Method converting mechanism for electric toothbrush and toothbrush comprising such mechanism |
| CN1331390A (en) * | 2000-06-23 | 2002-01-16 | 孙福山 | Intermittent reciprocating rotation mechanism |
| CN204297093U (en) * | 2014-12-15 | 2015-04-29 | 佛山市神风航空科技有限公司 | A kind of asymmetric rotary flapping wing aircraft |
-
2016
- 2016-09-15 NL NL2017463A patent/NL2017463B1/en not_active IP Right Cessation
-
2017
- 2017-09-12 WO PCT/NL2017/050598 patent/WO2018052288A1/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0599370A1 (en) * | 1992-11-18 | 1994-06-01 | Koninklijke Philips Electronics N.V. | Method converting mechanism for electric toothbrush and toothbrush comprising such mechanism |
| CN1331390A (en) * | 2000-06-23 | 2002-01-16 | 孙福山 | Intermittent reciprocating rotation mechanism |
| CN204297093U (en) * | 2014-12-15 | 2015-04-29 | 佛山市神风航空科技有限公司 | A kind of asymmetric rotary flapping wing aircraft |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2018052288A1 (en) | 2018-03-22 |
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| Date | Code | Title | Description |
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| MM | Lapsed because of non-payment of the annual fee |
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