NL2004905C2 - Strain wave gearing assembly. - Google Patents
Strain wave gearing assembly. Download PDFInfo
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- NL2004905C2 NL2004905C2 NL2004905A NL2004905A NL2004905C2 NL 2004905 C2 NL2004905 C2 NL 2004905C2 NL 2004905 A NL2004905 A NL 2004905A NL 2004905 A NL2004905 A NL 2004905A NL 2004905 C2 NL2004905 C2 NL 2004905C2
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- flexible
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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
- F16H49/00—Other gearings
- F16H49/001—Wave gearings, e.g. harmonic drive transmissions
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Description
STRAIN WAVE GEARING ASSEMBLY
The present invention relates to a strain gearing assembly, a strain wave drive system comprising of a plurality of stacked strain wave gearing assemblies a power 5 generator for generating electrical power comprising such strain wave gearing assembly and a motor comprising such strain wave gearing.
Strain wave gearings, also known as harmonic drive gears or harmonic drives, are input/output gearing mechanisms and as such are known. Basically, the strain wave gearing mechanism has three components: a wave generator, a flexible sleeve and a 10 rigid cylindrical sleeve. The wave generator is made up of an lobed disk, for example with an elliptical cross-section, and an outer ball bearing. The disk is inserted into the bearing, giving the bearing an elliptical shape as well. The flexible sleeve is generally cup-shaped. The side wall of the cup is thin and flexible, while the bottom part is thick and rigid. This results in significant flexibility of the walls at the open end due to the 15 thin side wall, but in the closed bottom part being quite rigid and able to be tightly secured to a support element, such as frame or shaft. Teeth are positioned radially around the outside of the flexible sleeve. The flexible sleeve fits tightly over the wave generator, so that when the wave generator disk is rotated, the flexible sleeve deforms to the shape of the rotating lobed disk but does not rotate with the wave generator.
20 The rigid cylindrical sleeve is provided with teeth on the inside. The flexible sleeve and generator are placed inside the rigid cylindrical sleeve, meshing the outer teeth of the flexible sleeve and inner teeth of the rigid cylindrical sleeve. Because the flexible sleeve has an elliptical shape, its teeth only actually mesh with the teeth of the cylindrical rigid sleeve in two regions on opposite sides of the flexible sleeve, along the 25 major axis of the ellipse.
The flexible sleeve has fewer teeth than there are on the rigid sleeve If the rigid cylindrical sleeve is connected to a reference point, for example a frame or shaft, this means that the rigid cylindrical sleeve rotates in the same direction as the wave generator, but in a slower rotation than the wave generator. If instead the rigid 30 cylindrical sleeve is connected to the reference point, then for every full rotation of the wave generator, the flexible sleeve rotates in the opposite direction and with a slower rotation than the wave generator. Such strain wave gearings may typically be used in 2 motion control and for gearing reduction, but may also be used, for example, to increase rotational speed, or for differential gearing.
In the known design, the rigid end of the cup that forms the flexible sleeve is fixed to a reference point, for example a stationary element, a frame or similar 5 structure. Consequently, the rigid end of the cup-shaped flexible sleeve acts as a retainer for the flexible part of the flexible sleeve. Due to the length of the cup-shaped flexible sleeve, i.e. the rigid and flexible part thereof, relatively much space is needed, which renders the strain wave gear assembly rather bulky. Furthermore, despite the extended length of the cup, the contact surface of the outer gear teeth of the flexible 10 sleeve still cannot be perfectly parallel to the contact surfaces of the inner teeth of the rigid cylindrical sleeve. This means that forces are transmitted at a relatively small contact area, which may result in a damage to the gearing.
It is an object of the present invention to provide a strain wave gearing assembly wherein the drawbacks of the prior art have been obviated or at least reduced.
15 It is a further object of the present invention to provide a cost effective and compact strain wave gearing assembly.
It is a further object of the invention to provide a strain wave gearing assembly providing for a good alignment between the inner teeth and outer teeth thereof.
According to a first aspect of the present invention at least one of the objects is 20 achieved in a strain wave gearing assembly, comprising: - a first support element; - a rigid second element, arranged to be rotatable around a rotational axis relative to the first element, the rigid second element comprising at least one lobe arranged at its outer surface; 25 - a flexible third element, arranged on top of the rigid second element, wherein the flexible third element comprises a first number of aligned teeth arranged at its outer surface; - a rigid fourth element arranged on top of the flexible third element, the fourth element comprising a second, different number of aligned teeth, arranged at the inner 30 surface of the element, wherein the teeth of the flexible third element are configured to engage the teeth of the fourth element so as to cause the fourth element to rotate upon rotation of the rigid second element or to cause the second element to rotate upon rotation of the rigid fourth ring element; 3 - a retainer assembly arranged between the first support element and the flexible third element to tangentially retain the flexible third element relative to the first support element in a rotational direction, while allowing movement of the flexible third element in a direction perpendicular to the rotational axis.
5 The first support element generally is a frame, a shaft, rotor, or any similar stationary or non-stationary element relative to which the third flexible element, for example a ring-shaped element, is to be retained. The retainer element, i.e. the element that may limit the motion of the third ring-shaped element in the direction of the motion of the moving parts of the gearing, is arranged between the support element and the 10 flexible element, which enables the volume and possibly also the mass of the gearing to be reduced with respect to common gearings that make use of the earlier mentioned cup-like structure.
In embodiments of the invention the retainer assembly is essentially one dimensional and may comprise, for example, a spring and/or an elastic pad or a series 15 of springs and/or pads, as will be described hereafter.
In embodiments of the invention a single retainer element may be sufficient to properly retain the third element relative to the first element. In other embodiments, two or more retained elements are used to retain the flexible third element. The retained elements may be located at any position, but in one of the embodiments of the 20 invention the retainer assembly comprises a first retainer element arranged at one end of the flexible third element and a second retainer element arranged at the opposite end of the flexible third element so as to maintain the flexible third element essentially parallel to the first support element. More generally, an essentially symmetrical and bilateral support of the flexible third ring by the retainer elements, enables ring-shaped 25 elements, for example pipe segments, to be made axially wider than in the conventional strain wave gearings. In a further embodiment of the invention the flexible third ring-shaped element can be blocked at both its circumferentials, further facilitating the use of a relatively wide flexible ring-shaped elements. In these embodiments a good parallel contact between the lobes of the second element and the inner surface of the 30 flexible third element can be realized. Furthermore, as will be discussed hereafter, an aerodynamic or hydrodynamic bearing pressure can be formed at relative ease between the third flexible ring and the lobed second ring when the third flexible ring is wide enough. This may greatly reduce the friction losses inside the gearing assembly, at least 4 with respect to the usual ball-bearings common in strain wave gears using the earlier mentioned cup-shaped sleeves. Such gearing assembly may be compact and/or lightweight and may require only a small number of components.
In embodiments of the present invention, herein sometimes referred to as the 5 "doughnut" configurations, the ring-shaped elements are configured as pipe segments. The assembly may then comprise: - a first support element, for example a rigid first pipe segment; - a rigid second pipe segment, arranged around the first pipe segment and arranged to be rotatably driven, the rigid second pipe segment having a plurality of 10 lobes extending in a generally axial direction along the outer surface of the second pipe segment; - a flexible third pipe segment, arranged around the rigid second pipe segment so as to be radially flexed by the lobes of the rigid second pipe segment, wherein the flexible third pipe segment comprises a first number of aligned teeth arranged at its 15 outer circumferential surface; - a rigid fourth pipe segment arranged around the flexible third pipe segment and comprising a second, different number of aligned teeth, arranged at its inner circumferential surface, wherein the teeth of the flexible third pipe element are configured to engage the teeth of the rigid fourth pipe segment so as to cause the rigid 20 fourth pipe segment to rotate upon rotation of the rigid second pipe segment or to cause the rigid second pipe segment to rotate upon rotation of the rigid fourth pipe segment; - a retainer assembly arranged between the support element, for example the rigid first pipe segment, segment and the flexible third pipe segment to tangentially retain the flexible third pipe segment relative to the rigid first pipe segment; 25 wherein the retainer assembly comprises a first retainer element arranged at one end of the rigid first pipe segment and a second retainer element arranged at the opposite end of the rigid first pipe segment so as to maintain the rigid first pipe segment essentially parallel to the flexible third pipe segment.
The pipe segments may be generally cylindrical, but different shapes are 30 conceivable as well. For example, one or more of the pipe segments may have an oval cross- section or an even more complex shape. More generally, the rigid second element, flexible third element and rigid fourth element may have nearly parallel planes 5 with widened contact lines, at which they move along each other, while the teeth of the flexible element engage the teeth of the abutting fourth element.
In other embodiments, herein also referred to as the "pancake" configurations, the ring-shaped elements are substantially flat. The assembly then may comprise: 5 - a rigid second flat ring-shaped element arranged so as to be rotatably driven relative to the first support element, the second flat rigid ring-shaped element having a plurality of lobes extending in a generally radial direction along the outer surface of the second flat rigid ring-shaped element; - a flexible third flat ring-shaped element, arranged on top of and concentric with 10 respect to the rigid second flat rigid ring-shaped element so as to be axially flexed by the lobes of the second flat rigid ring-shaped element, wherein the flexible third flat ring-shaped element comprises a first number of aligned teeth arranged at its upper surface; - a rigid fourth flat ring-shaped element arranged on top of the flexible third flat 15 ring-shaped element and comprising a second, different number of aligned teeth, wherein the teeth of the flexible third flat ring-shaped element are configured to engage the teeth of the rigid fourth flat ring-shaped element so as to cause the rigid fourth flat ring-shaped element to rotate upon rotation of the rigid second flat ring-shaped element; 20 - a retainer assembly arranged between the first support element and the third flexible flat ring-shaped element to tangentially retain the third flexible flat ring-shaped element relative to the first support element.
In the "pancake" configuration the ring-shaped elements may have an essential circular opening at its centre, i.e. may be punctured, and the flexible elements may 25 essentially connect the inner and outer circumferentials of the "pancake" elements.
The earlier mentioned retainer element(s) may be configured to impede rotation of the flexible third ring-shaped element in tangential direction, whilst allowing movement of the flexible third ring-shaped element in a direction perpendicular to the tangential direction. In case of the "doughnut" configurations movement in the radial 30 direction is allowed, while in the "pancake" configurations movement in the axial direction is allowed.
In some embodiments one or more of the retainer elements is fixed at its outer circumferential surface and its inner circumferential surface to the third flexible 6 pipe segment and the rigid first pipe segment respectively. The retainer elements may be fixed in such a way that the flexible third pipe segment is blocked in both rotational directions. In these embodiments the retainer assembly provides for a bidirectional retainment and substantially no movement in the tangential direction relative to the first 5 pipe segment is possible.
In other embodiments of the present invention the retainer element is configured to allow rotation of the flexible third pipe segment in a first rotational direction and to block rotation of the flexible third pipe segment in a second, opposite rotational direction. The assembly may perform a function similar to a "freewheel clutch". In a 10 further embodiment the retainer element comprises an upper retainer element part and a lower retainer element part. The upper retainer element part may include at least one tangential lip arranged to project obliquely downward and the lower retainer element part may include at least one tangential lip arranged to project obliquely upward. Furthermore, the lips are configured to enter into abutment when the retainer elements 15 parts are in contact with each other and the flexible ring segment tends to rotate in the second direction so that rotation in the second direction is impeded. The lips may be further configured to slide along each other when the flexible third pipe segment rotates in the first direction, opposite the second direction. Preferably the lips are resilient, for example because they are made of resilient material.
20 When the outer surface of the second ring-shaped element and the inner surface of the flexible third ring-shaped element are sufficiently parallel, for example when at both ends of the flexible third ring-shaped element a retainer element is used, the surfaces of the third ring-shaped element and of the (lobes of) the third ring-shaped element may be separated by a thin-air film. This air is being compressed in the narrow 25 path at the location of the lobes of the second ring-shaped element. Therefore also the shape of the lobes of the second ring-shaped element plays a role in the generation of a suitable air-cushion.
More general, in embodiments of the present invention the bearing between the outer surface of the rotatable rigid second ring-shaped element, for example the lobes 30 of the second ring-shaped element, and the inner surface of the flexible third ring- shaped element is a fluid bearing, i.e. a gas and/or liquid bearing. In fluid bearings a fluid, i.e. a gas, air and/or liquid is present between the bearing faces, for example between the outer surface of the rotatable rigid second pipe segment and the inner 7 surface of the flexible third pipe segment. In hydrodynamic bearings the rotation of one of the surfaces relative to the other sweeps a fluid in to the bearing, forming a lubricating effect. In case "air" is used instead of a liquid, this type of bearing may be referred to as an aerodynamic bearing.
5 In further embodiments of the invention both surfaces have a relatively low roughness value, for example a value Ra smaller than 0.1 micron. Because of this smoothness of the surfaces the generation of an effective air-bearing is enhanced, even at low speeds, which makes the friction losses in the gearing assembly relatively small indeed.
10 The use of two retainer rings in one of the embodiments of the present invention in combination with an outer and inner surface of the third and fourth ring-shaped elements respectively, make it possible to ensure particularly small friction losses and a wear reduction of the sliding contact surfaces of the gearing assembly. Furthermore, the retainer elements may be shaped, for example ring-shaped, so as to confine the air 15 bearing volume between them thereby strengthening the air bearing effect.
In further embodiments of the invention the air bearing effect may be enhanced by using grooves at one or both surfaces, such as being used in the so-called Spiral Groove Bearings, invented by Prof. Muijderman. In embodiments of the invention at least one of the outer surface of the rotatable rigid second ring-shaped element and the 20 inner surface of the flexible third ring-shaped element has one or more grooves, for example generally V-shaped or U-shaped grooves. In further embodiments of the invention both surfaces are provided with the V- and/or U-shaped grooves with a view to control the movement, i.e. the position, of the ring-shaped elements in an axial direction.
25 In further embodiments the outer surface of the rotatable rigid second ring-shaped element and the inner surface of the flexible ring-shaped element are configured to allow a sliding bearing at relatively low rotational speeds and a hydrodynamic or aerodynamic bearing, for example an air bearing, at higher rotational speeds of the second ring-shaped element.
30 The friction between the (smooth) inner surface of the flexible third ring-shaped element and that of the rigid second ring-shaped element during the start-up phase, when the air film has not been built up to a sufficient extent, may be minimized by ensuring sufficient hardness of the smooth contact surfaces. The hardness of the contact 8 surfaces be enlarged, for example, by anodizing the outer and/or inner surfaces and possibly performing an additional lapping operation. Additionally, needles or balls may be used as rotating bearing elements in between the smooth areas. Hydrodynamic bearings rely on bearing motion to sweep fluid in to the bearing and may have high 5 friction and short life at low speed or during starts and stops. Thus, an auxiliary bearing may be used during the start-up and shutdown phase to reduce the risk of damage to the hydrodynamic bearing.
In embodiments of the invention the second pipe segment has two lobes, preferably distributed at 180° angular distance. In other embodiments the pipe segment 10 may have one lob or three or more lobes distributed evenly along the circumference of the second pipe segment. For stability reasons the lobes of the second ring-shaped element pipe may be supported at three lines, at 120° angular distance. In this embodiment the second element can rotate stably in a three-line support. More lobes may provide even more stability and at a smaller number of lobes additional measures 15 are to be taken to ensure a mechanical stable function of the gearing. In the latter case rollers, sliding contacts and similar devices may be needed to provide for the required stability.
In an embodiment of the invention the rigid second pipe segment comprises a substantially cylindrical inner pipe segment part and an outer pipe segment part 20 forming one or more lobes relative to the circumferential surface of the inner pipe segment. In a more specific embodiment the rigid second pipe segment comprises a first cylindrical element and a thin walled second pipe element, for example an elongated strip-like element, connected to the outer circumferential surface of the first cylindrical element, the circumferential length of the thin walled second pipe element 25 being larger than the circumferential length of the first cylindrical element so as to cause the outer surface of the second pipe segment to be lobed. An advantage of this embodiment is that strip-like elements having at least one side with the required smoothness are readily available so that an additional step of polishing the surface of the pipe segment is not needed.
30 In an embodiment of the invention the strain wave gearing assembly comprises sealing rings for sealing off the space between the flexible third element and the first support element, each sealing ring being attached to an end portion of the flexible third element and the first element/retainer elements.
9
In embodiments of the invention the strain wave gearing assembly is integrated with a wave generator for rotatably driving the rigid second ring-shaped element or the rigid fourth ring-shaped element relative to the first support element. For example, the rigid second ring-shaped element may comprise a plurality of turbine blades. The wave 5 generator, that forms a drive system, may be configured to generate a stream of turbine fluid for example liquid and/or gas, water, along the turbine blades to cause the second or fourth ring-shaped input element to rotate in order to drive the fourth or second output element respectively. In other embodiments the strain wave gearing assembly is used in wind turbines for generating electrical energy. The gearing assembly may be 10 configured to transmit the relatively slow movement of the turbine blades, especially in case of large diameter wind turbines, into a relatively fast movement, for example, rotation of the electrical generator.
According to another aspect of the invention a strain wave gearing assembly is provided, the assembly comprising: 15 - a substantially first support element; - a second ring-shaped element, arranged to be rotatable relative to the first support element, the second ring-shaped element comprising a plurality of lobes arranged at its outer surface; - a substantially flexible third ring-shaped element, arranged on top of the second 20 ring-shaped element, wherein flexible third ring-shaped element comprises a first number of aligned teeth arranged at its outer surface; - a fourth ring-shaped element arranged on top of the flexible third ring-shaped element, the fourth ring-shaped element comprising a second, different number of aligned teeth, arranged at the inner surface of the ring-shaped element, wherein the 25 teeth of the flexible third ring-shaped element are configured to engage the teeth of the fourth ring-shaped element; - a retainer assembly arranged between the rigid first element and the flexible third ring-shaped element to tangentially retain the flexible third ring-shaped element relative to the first element; 30 wherein the first support element comprises a metal portion configured to be connected to an electric power source and wherein the rotatable second ring-shaped element comprises at least one magnet, the metal portion and magnet forming an integrated electric motor for driving the second ring-shaped element.
10
The combination of the metal portion forming a number of coils and the magnets make it possible to generate an magnetic field that can be used to rotate the rotatable second ring-shaped element. For example, a series of alternately oriented permanent magnets may be attached at the inner surface of the second ring-shaped element (i.e.
5 the drive ring). The magnets are activated by a rotating magnetic field, produced by controlling, for example by pulse modulation of, the current provided by the power source in the successive coils, placed near and parallel to the magnets.
In an embodiment of the invention the first support element is a rigid first pipe segment, the rigid first pipe segment comprising a generally cylindrical, thin walled 10 metal pipe portion arranged between stationary end plates. The metal pipe portion may be made of copper or any other suitable conductive material.
Due to the high transmission ratios that are possible using the present strain wave gearing assembly the number of windings of the metal coil can be kept rather small. The thin-walled metal portion may be provided with a pattern with relatively short and 15 thick metal strips. In a further embodiment a meandering pattern is present in the thin- walled metal pipe portion. For example, an essentially rigid meandering pattern may be made cost-effectively by stamping a metal strip or by any other suitable method of fabrication.
In a specific embodiment the assembly comprises a rotatable rigid second pipe 20 segment, the second pipe segment being provided at the inner surface thereof with at least one magnet, preferably a plurality of magnet elements. In embodiments of the invention 50-70 permanent magnet strips may be used, for example in the gearing of a bike. In other embodiments fewer of more magnets or magnet strips may be used, for example up to 1200 or more magnets in de wind turbine mounted axially at the inner 25 circumferential surface of the second rigid pipe segment. The second pipe segment is placed freely around the first support element, for example a first rigid pipe segment formed by the earlier-mentioned meandering metal portion (sleeve).
In an embodiment of the invention the strain wave gearing assembly comprises a sensor for detecting an alignment between the at least one of the magnet elements and 30 the meander patterns. The sensor can be for example a Hall-sensor or an optical sensor.
In an embodiment of the invention the strain wave gearing assembly the power source is connected to the sensor for generating a modulated current through the meandering pattern in dependence of the detected alignment between the one magnet 11 element and the meander pattern. By adjusting a predetermined period between a pulse of the modulated current through the meander pattern and the instance of alignment of the one or more magnets with the meander patterns, the induced magnetic forces can act in an accelerating or decelerating way between the rigid second ring-shaped 5 element on the one side, and the first support element and the flexible third ring-shaped element on the other side. Accordingly, the strain wave gearing assembly will act as drive or brake.
In an embodiment of the invention the rigid fourth ring-shaped element is a rigid element that is part of or connected to an output shaft. The reduction ratio of this 10 embodiment may be defined as the difference of the number of teeth fourth element and the number of teeth of the third element, divided by the number of teeth of the third element. In other embodiments the first support element is a rigid element and is part of or connected to an output shaft. In this embodiment the reduction ratio may be defined as the difference by the number of teeth of the fourth element and the number of teeth 15 of the third element, divided by the number of teeth of the fourth ring. In practical embodiments of the present invention a wide range of transmission ratios may be realized, for example transmission ratios between 1:20 and 1:2000.
According to another aspect of the present invention a strain wave gearing assembly is provided, the assembly comprising: 20 - a first support element; - a rigid second ring-shaped element, arranged to be rotatable relative to the first support element, the rigid second ring-shaped element comprising a plurality of lobes arranged at its outer surface; - a substantially flexible third ring-shaped element, arranged on top of the rigid 25 second ring-shaped element, wherein flexible third ring-shaped element comprises a first number of aligned teeth arranged at its outer surface; - a rigid fourth ring-shaped element arranged on top of the flexible third ring-shaped element, the fourth ring-shaped element comprising a second, different number of aligned teeth, arranged at the inner surface of the ring-shaped element, wherein the 30 teeth of the flexible third ring-shaped element are configured to engage the teeth of the fourth ring-shaped element; wherein the flexible third ring-shaped element and/or the fourth rigid ring-shaped element comprises a carrier ring and a pleated strip of flexible material, for example 12 polycarbonate, attached to the carrier ring, the pleats of the strip forming an array of flexible outer and/or inner teeth of the third flexible ring-shaped element and/or the fourth ring-shaped element, respectively.
Due to the flexibility of the pleated strip forming the teeth according to this 5 embodiment the risk of damage to the teeth, for example, at high torque levels, is reduced. Furthermore the transmission may run more smoothly than in case teeth are used that have been milled in the respective ring-shaped element. A further advantage of using the teeth according to this embodiment of the invention is that they allow for relatively high transmission ratios, which means that the rotational speed difference 10 between the contact surfaces of the second and third ring-shaped elements will be relatively large. A large speed difference makes it easier to provide for an air bearing between the contact surfaces and hence a relatively low friction.
The contact surfaces between the second and third ring-shaped elements and/or between the third and fourth ring-shaped elements may be essentially line-shaped. In 15 other words, the contact surfaces define a line contact rather than a point contact.
In embodiments of the invention the retainer elements may at least partly comprise resilient material. The resilient material may result in a contact between the flexible ring-shaped element and the first element so as to impede movement in the tangential direction, while due to the resilient characteristics of the material, allow the 20 flexible ring-shaped element to move more or less freely in a direction perpendicular to this tangential direction. The resilient material could be formed, for example, by foam or felt, for instance open-pore polyurethane foam. Other materials, such as steel wool coated with epoxy to connect the steel wires at their crossing points and/or a strip of undulating steel ribbon, could be used as well for the same purpose.
25 According to a further aspect of the present invention a plurality of stacked strain wave assemblies as defined herein is provided. For example, a number of strain wave gearing assemblies according to the "pancake configuration" may be connected in a parallel manner to an output shaft so that a higher level of output torque can be provided. According to other embodiments a number of strain wave gearing assemblies of the 30 "doughnut" configuration may be stacked by arranging them in series, one around the other, so that the rotational speed of the output shaft may be decreased or increased. When only the second ring-shaped element of the first, innermost strain wave gearing assembly is driven and the last, outermost fourth ring-shaped element forms the output 13 shaft, an especially high transmission ratio can be created effectively. In further embodiments one or more strain wave gearing assemblies of the "pancake" configuration are combined with one or more strain wave gearing assemblies of the "doughnut" configuration.
5 According to another aspect of the invention a motor is provided, the motor comprising a strainwave gearing assembly as defined herein.
According to another aspect of the invention a vehicle is provided comprising a strainwave gearing assembly as defined herein.
According to another aspect of the invention a power generator for generating 10 electrical power is provided, the generator comprising a turbine having a rotor, the rotor being part of or connected to the rigid fourth ring-shaped element of the strain wave gearing assembly as defined herein.
The term "rigid" element herein is used to describe embodiments of the invention wherein the element is rigid to the extent that, when in use, the element provides for an 15 essentially stable movement (e.g. rotation) of the element relative to one or more other elements. For example, when the rigid element is a rigid pipe segment, the pipe segment may be may of essentially hard and inflexible material, but in other embodiments the pipe segment is flexible to some extent. In an embodiment of the invention the rigid ring-shaped element may be a caterpillar track or similar 20 construction. The caterpillar track may be supported by a couple of wheels, a sliding plate or a similar support structure.
Further details, characteristics and features of the present invention will be elucidated in the following description of several embodiments thereof. In the description 25 reference is made to the annexed drawings, in which show:
Figure 1 a partly cut-away perspective view of an embodiment of a strain wave gearing assembly;
Figure 2 a longitudinal section along I-I of the embodiment of figure 1;
Figure 3 a partly cut-away view of the embodiment of figures 1 and 2; 30 Figure 4 a longitudinal section of another embodiment of the invention;
Figure 5 a detailed cross-section of the embodiment of figures 1 and 2;
Figure 6 a schematic representation of the inner ring, flexible ring and outer ring of the doughnut shaped embodiment of figures 1-5; 14
Figure 7 a detailed view of a part of an embodiment of the strain wave gearing assembly, in cross section;
Figure 8 an exploded view showing the drive ring assembly of the doughnut shaped configuration of Figures 1-7; 5 Figure 9 a view of the drive ring assembly of figure 7 in assembled position;
Figure 10 a cross section of another embodiment of the strain wave gearing assembly in a pancake configuration;
Figure 11a top view of the embodiment having a pancake configuration.
Figure 12A a top view of a strip provided with Muijderman grooves; 10 Figure 12B a side view in perspective of the butt-welded strip of figure 11A;
Figure 13 a schematic view of an embodiment of a combination of doughnut-type and pancake-type strainwave gearing assemblies; and
Figure 14 a strainwave gearing assembly provided with a power supply, an electronic circuit for generating a modulated current and a sensor.
15
In a conventional strain wave gearing assembly comprises an electric motor that rotates a so called wave generator. A wave generator comprises an elliptical disc surrounded by a bearing that flexes diametrically opposite portions of a surrounding flexible ring. The flexible ring is on the outer surface thereof provided with outer gear 20 teeth for engaging with inner gear teeth of an output ring or output member surrounding the flexible ring. The output ring is a generally inelastic while the flexible ring is flexible so that the latter may take the shape of the rotating elliptical disc of the wave generator. The flexible ring generally has a fewer number of outer teeth than the output ring so that the rotation of the elliptical disk results in a reduction of the 25 transmission ratio between the wave generator and the output member.
In this type of strain wave gearing assemblies the flexible ring is embodied as axially oriented cup-shaped pipe, also referred to as the cup, of which the very circumferential end acts as the flex ring. Due to the length of the cup-shaped flexible ring its circumferential end enables motion in a radial direction. The other, opposite end 30 of the cup is closed and is fixed to a stationary element, for example a frame, preventing the cup-shaped flexible ring to rotate.
An example of such strain wave gearing assembly using a cup-shaped flexible ring is known from US 2006/0283289 A1.
15
However, due to the length of the cup-shaped flexible ring, relatively much space is needed which renders the known strain wave gearing assemblies rather bulky.
Furthermore, despite the extended length of the cup, the contact surface of the outer gear teeth of the flexible ring still cannot be perfectly parallel to the contact 5 surfaces of the inner teeth of the output ring. This means that forces are transmitted at a relatively small contact area between the outer and inner teeth, which may result in a damage to the drive or may limit the maximum allowable torque.
Fig. 1 shows a partly open view in perspective of a first embodiment of a strain wave gearing assembly 1, wherein the strain wave gearing assembly comprises a so-10 called doughnut configuration. This embodiment can be applied in a drive for a vehicle, e.g. a bicycle. Figs 2,4,5 and 6 show further details of the first embodiment. Shown is a casing 3 through which a central spindle 2 or shaft extends. The casing 3 comprises a ring-shaped element 20, hereafter called the driven ring, a first side wall 90 and a second side wall 91. The structure offside walls and ring-shaped element is rotatable 15 trough bearings 94 around the shaft 2. In the embodiment shown in Fig. 1 the side wall has been provided with a number of holes 93 arranged at their respective circumferentials. These holes 93 are able to engage with spokes (not shown) of a bicycle wheel. The interior of the casing 3 has been provided a number of rings in a concentric way with the central shaft 2. Two, perpendicular with the central shaft 2 20 extending side plates 4,5 are connected to the central shaft 2. A stiff ring 6 is provided at the ends of the respective side plates 4,5. The side plates 4,5 and the stiff ring 6 form a cylindrical ring-shaped element 70. In this embodiment also called the driving part 70. The carrying forces on the bicycle wheel are guided via the bearings 94 on the central shaft 2. Furthermore, a stiff ring-shaped element 7, a so-called driving ring, is 25 provided, rotatable with respect to the cylindrical driving part 70. As shown in detail in Fig. 6, the driving ring 7 is provided with an number of lobes 8 at the its outer circumference. The driving ring may be built of massive material. In an embodiment as shown in Figs 4 and 5, the driving ring 7 comprises actually two sub-rings. At the inner side a first driving sub-ring 12 is provided, which can be rotated in a way as is 30 described in this description. A second driving sub-ring 10 is provided at the outer side there of, whereby a few points of the second sub-ring are connected with the first sub-ring 12.
16
By selecting the circumference of the second sub-ring 10 sufficiently larger then the circumference of the first sub-ring 12, the second sub-ring 10, which has a substantially cylindrical shape, will form one or more of the said lobes 8. The non-rotatable stiff ring 1 with the lobes 8 and the driving ring 7 constitute a so-called wave 5 generator. The strain wave gearing assembly further comprises a, flexible gear-teeth ring 15, which is flexible in a sense that this gear-teeth ring will conform itself to the shape of the passing lobes 8 of the wave generator. The exterior of the flexible gear-teeth ring 15 is further provided with a large number of exterior teeth 17. In an embodiment the flexible gear-teeth ring can be manufactured of fibers, e.g. in a 10 manufacturing process wherein in a first step glass fibers are wrapped around a spike and in a next step the poly-urethane raisin is applied to form a fiber layer. During the poly-merisation the fibers and the raisin are guided through a extrusion apparatus. The interior of the extrusion apparatus may be provided with pattern of grooves to provide the flexible geared teeth ring of a groove pattern. These grooves can form a teeth 15 structure in the polyurethane layer, which teeth engage with teeth of the output ring. Other embodiments of the flexible gear teeth ring are possible and can be envisaged by a person skilled in the art. The strain wave gearing further comprises a so-called inner gear teeth driven ring 20 around the flexible gear teeth ring 15. The interior surface of the inner gear teeth driven ring 20 has been provided with inner teeth 22. The number 20 of inner teeth of the inner gear teeth ring 20 is different of the number of teeth of the flexible gear teeth ring 15, such that a rotation of the inner gear teeth ring 20 through rotation of the wave generator causes an acceleration or deceleration of its rotation. In this way, a proper selection of these numbers provides for a faster or slower rotation of the inner gear teeth driven ring 20 with respect the drive ring 15.
25 In operation, care should be taken that by rotating of the drive ring 7, provided with the lobes 8, the flexible gear teeth ring 15 follows the movement of the passing lobes in a radial direction (P), while being blocked in a rotational direction (R).
As described above, in a conventional flexible gear drive assembly a non-rotatable flexible cup-shaped element is applied which is attached the static casing 3 of the 30 strain wave gearing assembly. The circumferential of this element can deform in a radial direction such that a movement of the lobes 8 of the drive ring 7 can be followed, while being blocked for a rotation due to the fixation at the casing 3. In the embodiment shown in Fig. 1 the flexible gear teeth ring 15 is just not cup-shaped and, basically, is 17 able to rotate with respect to the drive ring 7. In order to counteract this rotation one or more retainer assemblies 30,31 have been provided between the stiff first ring 6 and the flexible gear teeth ring 15. The retainer assemblies are attached near the circumferential of the flexible gear teeth 15.
5 An embodiment of the retainer assembly, as shown in Fig. 2 and Fig. 3, comprises a substantially ring-shaped retainer element 35 extending along the said circumferential of the flexible gear teeth ring 15 and said elements 4, 5. The retainer element has resilient characteristics. For example, the retainer element can be manufactured out of elastic material, such as foam. Other materials comprise 10 polyurethane foam with open pores, felt or similar materials.
Due to the elastic characteristics the retainer element is compressible in a radial direction P, when one of the lobes 8 passes, and can expand to its original shape when the lobe has passed. The upper side of Fig. 2 shows a retainer element which is slightly compressed due to the influence of a lobe of the rotating ring 7, while the lower side of 15 Fig.2 shows a retainer element relaxed to original shape by absence of the lobe 8. In this way, the distance in radial direction, indicated by respective arrows, between the radial side of the elements 4,5 and the circumference of the flexible geared teeth ring 15 may vary as required.
The material of the retainer element is arranged in such a way that a pressure 20 exerted by the retainer element 35 on the flexible ring 15 counteracts rotation of the flexible ring, in particular the drive ring 7, with respect to the wave generator. Alternatively phrased, the retainer element causes such a high friction in a tangential direction, that at rotation of the drive ring 7 a rotation of the flexible gear teeth ring is counteracted or even prevented. The embodiment shown in Figs 2,3 and 4 is provided 25 with retainer elements at both ends, such that the flexible gear teeth ring 15 is maintained parallel with respect to the drive ring 7. In an embodiment the retainer elements have been arranged at a largest possible distance from each other. In other embodiments a single retainer element 30, 31 can fixate the flexible gear teeth ring 15 in a rotation direction with respect to the drive ring 7 .
30 Furthermore, in the embodiments shown in Fig.2 and Fig.3 the retainer elements 35 are implemented as rings. In other embodiments a few, small retainer elements may provided at the circumferential of the flexible gear teeth ring 15, which retainer elements extends each along a small arc segment of the circumference.
18
The embodiment shown in Fig. 4 is provided with a retainer ring assembly 36, besides the retainer element 39, which has been manufactured of flexible material. The retainer ring assembly comprises a inner fixation ring 37 and an outer fixation ring 38. Resilient lips is provided at the interior of the outer fixation ring 38 and at the 5 exterior of the inner fixation ring 37. In operation, these lips of the inner fixation ring 37 and the outer fixation ring 38 will slide along each other upon rotation in a first direction, so that rotation in this direction remains possible. Upon rotation in the opposite direction, the lips of the outer fixation ring 38 will engage with the lips of the inner fixation ring 37 and therewith prevent rotation of the flexible gear teeth ring 15 10 with respect to the drive ring 7. In this way the retainer assembly has been arranged such that rotation of the flexible geared teeth ring 17 in one direction is possible, while rotation in the opposite direction, is blocked or at least counteracted.
In the embodiments described, the support element comprising the stiff ring 6 is stationary with respect to the flexible gear teeth ring 15, while the drive ring 7 is 15 rotatably arranged with respect to the rings 6,15. Driving drive ring 7 brings about a rotation of the driven ring 20. In other embodiments the function of the driving ring and the driven ring can be interchanged. In an alternative operation mode, rotating the inner geared teeth ring 20 will bring about rotation of de drive ring 7. In still further embodiments both operation modes are interchangeable depending on the required 20 function, so that the concerned strain wave gearing can operate in both modes. Also in these last described embodiments the retainer assemblies 30,31 enables a movement of the concerned rings 7,15 with respect to each other, while block a rotation in at least one direction.
Fig. 7 shows a further embodiment of a flexible gear teeth ring 15 and/or 25 the inner gear teeth ring 20. Fig. 7 shows diagrammatically the former described outer sub-ring 10, which forms the lobes 8. The lobes 8 enable movement of the flexible gear teeth ring back and forth in a radial direction. The teeth of the exterior surface 16 of the flexible gear teeth ring 15 have been formed by a folded film, or form folds of a elongated strip. These folded film has been attached at a number of discrete positions of 30 a flexible carrier 40. In this way, the teeth 17 can be provided with such a flexibility that a relatively smooth movement can be obtained with respect to embodiments provided with a flexible gear teeth ring wherein the teeth and the carrier form a single massive body. For example, in embodiments wherein the teeth have been milled in the 19 flexible gear teeth ring 15.
An advantage of this flexible arrangement is that the flexibility of the teeth enables transmission of a relatively large torque, because several teeth of both the flexible gear teeth ring 15 and the driven ring 20 are simultaneously engaged. A further 5 advantage is an improved relief of shocks and therewith accompanied smooth functioning of the transmission.
In the embodiment shown in Fig. 7 besides the teeth of the flexible ring 15, also the inner teeth of the inner gear teeth ring 20 are formed by a folded film. Fig. 7 shows that the inner gear teeth is construed by a relatively stiff exterior carrier 43, on which a 10 folded film is attached at a number of positions. In this way, flexible teeth can be provided, which engage with the already described flexible gear teeth ring 15.
In an embodiment the teeth have been provided in a V-profile, wherein the individual V-shape are arranged along the tangential surface of the flexible gear teeth ring 15. As indicated earlier, the ring 7 is provided with two or three protrusions or 15 lobes. In operation, these lobes 8 push the flexible gear teeth ring 15 , teeth by teeth, over the inner teeth 22 of the inner gear teeth ring 20 so as to move the inner gear teeth ring. In the shown embodiments, the engaged and moving teeth 17,22 are hereby in a substantially line contact with each other. In particular, the contact surface between the outer teeth and the inner teeth has a smooth extended contact field with a substantially 20 wedge shape. This causes, at the start of a movement of the second ring 7, a slide bearing effect which may convert in an air/ liquid bearing effect, depending of the medium present between the teeth.
In an embodiment the inner surface 46 of the flexible gear teeth ring 15 and the outer surface 47 of the drive ring 7, at least the exterior of the sub-ring 10 thereof, are 25 very smooth. Preferably, the smoothness Ra, defined according the International Organization for Standardization (ISO)1302:2002 standard of the surface, may be smaller than 0,1 pm, such that a very low friction between both surfaces can be obtained. The low friction between the exterior surface 47 of the drive ring 7 and the interior surface of the flexible gear teeth ring 15 creates a supporting air layer between 30 both surfaces. This air layer can be further promoted by providing a relatively high difference in speed between both contact surfaces. Also the wedge shaped contact line promotes the creation of the air layer. The high speed of the surface of the lobes of the drive ring 7 pushes the air layer into the wedge shape, causing a supporting air 20 pressure.
In a further embodiment, shown in Fig 12 A and 12 B, the opposed surfaces 46,47 of the drive ring 7 and/or of the flexible gear teeth ring 14 have been provided with grooves. The grooves may be provided with smooth slide contact fields. For 5 example by etching the grooves. Preferably, these grooves have a substantially V-shape or U-shape. Fig 12 A and Fig. 12 B show an embodiment of these grooves. In this embodiment a carrier film, e.g. a polycarbonate foil, is provided with a pattern consisting of a large number of V-shape or U-shape grove by an electrostatic printer. The toner of the electrostatic printer may comprise a suitable thermo plastic material 10 and wear-resistant toner particles with a diameter of, for example, 20 pm.
Fig. 12 A shows a carrier film 50 provided with such grooves 48. The carrier shape is conformed to a ring shape and the end of the V-shape or U-shape are butt-welded, after which the carrier film is provided at the interior surface of the flexible gear teeth ring 15. For example, the carrier film can be glued at flexible outer gear teeth 15 ring. These known grooves, the so-called Muijderman-groves, improve the air cushion between both rings and reduce the friction between both rings. Instead of these slide contact air layer hydraulic bearings it is possible to provide this bearing with a series of parallel needle bearings and/or a series/array of ball bearings. Muijderman grooves are known from "Spiral Groove Bearings", Philips Technical Library, Muijderman E.A, 20 1966.
In the described embodiments the drive ring can be formed by the second ring shaped element or by the fourth ring shaped element 20. Driving of the drive ring can be performed in various ways. For example, in a mechanical way by the shaft of a wind mill or alternatively an hydraulic or pneumatic turbine.
25 In an embodiment the concerned ring can be driven via a rotating magnetic field. Fig. 1-4, 8 en 9 show an embodiment of such magnetic drive. Fig 8 shows an exploded view of a part of the embodiment of Fig. 1 and Fig. 2. Fig 9 shows the assembled part of switch gearing assembly. Fig. 8 shows, amongst other, the shaft 2, the side plates 4,5, both retainer assemblies 30,31 and the first support element. In this embodiment the 30 rigid first ring 6 comprises a thin walled copper pipe, attached to the static side plates 4,5. The copper pipe is provided with a meander pattern in an axial direction. The meander pattern can be connected with three phases of an electric power supply unit. Furthermore, the interior of the rotating ring, as shown in Fig. 2,3 or 4 is provided with 21 magnetic strips. The number of magnet strips is freely selectable. In this embodiment it is about 62. The magnet strips are provided in such a way that the north and south poles of adjacent magnet strips are oppositely arranged with each other. In operation, the meander pattern of the copper ring 6 generates a rotating magnetic field due to a 5 modulated current provided by the power supply unit 150. The resulting rotating magnetic field induce a force between the magnet strips and the meander pattern and cause rotation of the drive ring 7.
In this embodiment the strain wave gearing with a high transmission ratio between the different rings enables magnetic driving. This meander pattern 10 configuration comprises a relatively few thick coils, wherein the resistive losses can be relatively small. Also the meander pattern can be easily manufactured on the copper pipes. For example, by pressing the pattern in the copper pipe. A further advantage is that the low resistance enables easy adjustment of the motor torque because the motor torque depends proportionally on the effective current through the coils, and is 15 substantially independent of the rotational speed.
Fig. 14 shows an embodiment of the strain wave gearing assembly 13 provided with a power supply unit 150, which is electrically connected with the meander pattern 56 of the first copper ring 6. The power supply unit comprises an electronic circuit 151 and a sensor 153 for determining the position of the magnet strips 55 with respect to the 20 coils of the meander pattern 56. The sensor 153 is electrically connected with the electronic circuit 151. The sensor may comprise a Hall-element or an optical sensor.
In operation, the power supply unit 105 generates a modulated current through the coils of the meander pattern. The modulated current comprises one or more current pulses, in dependence of the detected position of the magnet strips with respect to the coils of the 25 meander pattern. The generated current pulses in the meander coils generate the rotating magnetic field that cause rotation of the drive ring 7. By selecting a time period between the instance of the current pulse and the instance of alignment between the magnet strips and the meander coils or vice verse, and the direction of the current through the meander coils, the induced force can be accelerating or decelerating the 30 drive ring 7.
A further advantage of is that this motor can be built in a compact protective casing without a danger for overheating, because its low resistive losses and low friction losses. This compact and protective casing enables application of strain wave 22 gearing assembly in harsh environments, for example sea and mines, because the interior of the strain wave gearing assembly is protected against degrading external influences .
A further advantage of a motor provided with a strain wave gear assembly is its 5 low non-suspended weight that can be realized in a combination of motor and wheel for use in driving and braking a vehicle.
A further advantage of a motor provided with a strain wave gear assembly is that the high transmission ratio enables easy reduction of high frequency oscillations caused by the modulated current through the motor.
10 Referring to Figs. 1-9, embodiments have been described wherein the strain wave gearing assembly has a so-called doughnut configuration. Figs 10 and 11 shows a an embodiment of a strain wave gearing assembly with a so-called pancake configuration. In this configuration a number of flat rings are provided, wherein a ring is provided with a number of lobes, for example two or three, which move a different, 15 flexible ring in an axial direction instead of a radial direction (outward direction). An advantage of this embodiment is that it can be assembled in a very compact way, as elucidated hereafter.
Fig. 10 shows a cross-section parallel with the central axis of the embodiment of a strainwave gearing assembly with a pancake configuration. Fig. 11 shows a partly 20 opened view of the upper section. This embodiment comprises a drive motor with a drive element that runs in a substantially circular orbit. Furthermore, the drive element 60 comprises a flat ring shape. In operation, the drive motor drives the drive element 60 via the circumferential side of the drive element. The drive element 60 forms a number of lobes 62, which move a flexible flat ring 61, provided under the drive element 60, in 25 a downward direction. Fig. 10 shows a case wherein the left side of flexible ring 61 has moved itself upwards, while the right side of the flexible ring has moved itself downwards. Fig. 11 shows a cross-section of the flexible flat ring 61 perpendicular with the central axis, wherein reference A indicates the downwards moved areas of the flexible ring 61 and reference B indicates the upwards moved areas. A driven flat ring 30 64 has been provided underneath the flexible flat ring 61. The driven ring 64 has been connected to a driven output shaft. The lower side of the flex ring 61 has been provided with a number of teeth 67 which engage with a number of teeth 68 provided at the upper side of the driven ring 64. The number of teeth 67 of the flexible gear teeth ring 23 61 is different than the number of teeth 68 of the driven ring 64. The flexible flat ring 61 projects a little in a radial direction with respect to the driven flat ring 64. At the position of this radial border of the flexible flat ring 61 a ring-shaped retainer element 66 has been provided. The ring shape or a ring-segment retainer element is made of a 5 foam material. The retainer element 66 counteracts a rotation of the flexible gear teeth ring 61 in a tangential direction, while a movement caused by the passing lobes in a radial direction remains possible. The shown embodiment is provided with two, ring segmented, retainer elements, which extend only for a small part along the border of the flexible ring 61. In other embodiments a single retainer element suffices or 10 alternatively the retainer ring can be formed as an enclosed circle around the circumference of the flexible ring 61. In such embodiments the contact surfaces of the teeth of the flexible gear teeth ring 61 and the drive ring 64 are radially directed.
In further embodiments, not shown, instead of a single strain wave gearing assembly a number of strain wave gearing assemblies can be stacked and coupled in 15 parallel or in series with respect to each other. For example, the pancake type gearing assemblies can be used in parallel and driven, for example, at their common outer circumference. The inner circumference of the output disks or rings can be connected via an output shaft, fit to withstand the high output torque created by the parallel pancakes type of gearings. In doughnut type gearing assemblies the ring-shaped output 20 element of a first gearing assembly may be used as the ring-shaped input element of a second gearing assembly.
Other embodiments include a stacked doughnut configuration that is used in a clock to drive one ring at one revolution per second, driving the second ring at one minute per minute and the third ring at one revolution per hour. The position of the 25 three rings represents the time is this specially designed, clock.
In still another embodiment a number of pancake type strain wave gearing assemblies are arranged in series. The pancake type strain wave gearings may be enclosed by a doughnut type gearing assembly. Such configurations enables a combination of a very low rotation speed with a very high torque at the output shaft and 30 compact dimensions. Multiple strain wave gearing assemblies of the pancake type parallel coupled with a single output shaft enable very high output torques. In an embodiment wherein multiple strain wave gearing assemblies of the doughnut type are 24 applied, these may be coupled in series, whereby one gearing is built around the other. In this way an arbitrary transmission ratio can be effectively realized.
Figure 13 shows an embodiment of a stacked assembly comprising a multiple strain wave gearing assemblies as described herein. The figure shows actually two 5 different embodiments of stacked strain wave gearing assemblies. In a first embodiment an input shaft 80 is attached to wave gearing assemblies and drives the same. The first strain wave gearing assembly 81 may be an assembly according to the above-mentioned pancake configuration, for example similar to the embodiment shown in figures 10 and 11. The first strain wave gearing assembly 81 in turn drives a second 10 strain wave gearing assembly 82 of the doughnut configuration, for example similar to the embodiment of figure 2/3 or 4. Therefore the ring-shaped output element 85 of the strain wave gearing assembly 83 may be rotated by a combination of the "pancake" and "doughnut" type of gearings, for example for driving a generator 83
In the second embodiment the shaft 80 is a low velocity output shaft and the 15 assembly 85 is driven by a ring motor, similar to the embodiments described in connection with figures 2/3 or 4. The relatively high output torque of the doughnut type gearing assembly 82 may be used as the input for a series of parallel pancake type gearing assemblies 81 such that high torque, low speed combinations can be made in a relatively small compartment.
20 The invention is not restricted to the preferred embodiment as described above.
The requested rights will be defined by the claims and the protection conferred thereof wherein many modifications are possible.
Claims (35)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2004905A NL2004905C2 (en) | 2010-06-16 | 2010-06-16 | Strain wave gearing assembly. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2004905 | 2010-06-16 | ||
| NL2004905A NL2004905C2 (en) | 2010-06-16 | 2010-06-16 | Strain wave gearing assembly. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| NL2004905C2 true NL2004905C2 (en) | 2011-12-20 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NL2004905A NL2004905C2 (en) | 2010-06-16 | 2010-06-16 | Strain wave gearing assembly. |
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| NL (1) | NL2004905C2 (en) |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3119283A (en) * | 1962-04-23 | 1964-01-28 | Gen Motors Corp | Power transmission |
| DE2520368A1 (en) * | 1975-05-07 | 1976-11-18 | Juergen Ing Grad Muellerschoen | Shaft speed reduction gearing - uses bevelled cup gears and roller cam fixed to drive shaft |
| US4003272A (en) * | 1975-01-31 | 1977-01-18 | Dmitry Pavlovich Volkov | Harmonic gear reduction unit |
| FR2450390A1 (en) * | 1979-03-01 | 1980-09-26 | Borg Warner | ROTARY DRIVE DEVICE |
| US5079754A (en) * | 1990-05-07 | 1992-01-07 | Huang Kuo C | End-face waving gear reducer |
| EP1319870A1 (en) * | 2001-12-11 | 2003-06-18 | Teijin Seiki Co., Ltd. | Flex spline for meshing type gear device and meshing type gear device having flex spline |
| US20060283289A1 (en) * | 2005-06-16 | 2006-12-21 | Baudendistel Thomas A | Harmonic drive motor with flex-spline interlock |
| DE102006060295A1 (en) * | 2006-12-20 | 2008-06-26 | Zf Friedrichshafen Ag | Reduction gear, has thin-walled wave-shaped deformable flexible wheel contacting with hollow wheel in two diametric regions, and gearing that is designed as helical gearing at hollow wheel and flexible wheel |
| DE102008061672A1 (en) * | 2007-12-15 | 2009-06-18 | Hirschmann Automotive Gmbh | Sliding wedge gear, used in a sensor arrangement |
-
2010
- 2010-06-16 NL NL2004905A patent/NL2004905C2/en not_active IP Right Cessation
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3119283A (en) * | 1962-04-23 | 1964-01-28 | Gen Motors Corp | Power transmission |
| US4003272A (en) * | 1975-01-31 | 1977-01-18 | Dmitry Pavlovich Volkov | Harmonic gear reduction unit |
| DE2520368A1 (en) * | 1975-05-07 | 1976-11-18 | Juergen Ing Grad Muellerschoen | Shaft speed reduction gearing - uses bevelled cup gears and roller cam fixed to drive shaft |
| FR2450390A1 (en) * | 1979-03-01 | 1980-09-26 | Borg Warner | ROTARY DRIVE DEVICE |
| US5079754A (en) * | 1990-05-07 | 1992-01-07 | Huang Kuo C | End-face waving gear reducer |
| EP1319870A1 (en) * | 2001-12-11 | 2003-06-18 | Teijin Seiki Co., Ltd. | Flex spline for meshing type gear device and meshing type gear device having flex spline |
| US20060283289A1 (en) * | 2005-06-16 | 2006-12-21 | Baudendistel Thomas A | Harmonic drive motor with flex-spline interlock |
| DE102006060295A1 (en) * | 2006-12-20 | 2008-06-26 | Zf Friedrichshafen Ag | Reduction gear, has thin-walled wave-shaped deformable flexible wheel contacting with hollow wheel in two diametric regions, and gearing that is designed as helical gearing at hollow wheel and flexible wheel |
| DE102008061672A1 (en) * | 2007-12-15 | 2009-06-18 | Hirschmann Automotive Gmbh | Sliding wedge gear, used in a sensor arrangement |
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| V1 | Lapsed because of non-payment of the annual fee |
Effective date: 20140101 |