NL2021361B1 - Electric low-power supply system for devices and device comprising such a low-power supply system - Google Patents
Electric low-power supply system for devices and device comprising such a low-power supply system Download PDFInfo
- Publication number
- NL2021361B1 NL2021361B1 NL2021361A NL2021361A NL2021361B1 NL 2021361 B1 NL2021361 B1 NL 2021361B1 NL 2021361 A NL2021361 A NL 2021361A NL 2021361 A NL2021361 A NL 2021361A NL 2021361 B1 NL2021361 B1 NL 2021361B1
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- power supply
- supply system
- spring
- low power
- torsion spring
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- G—PHYSICS
- G04—HOROLOGY
- G04C—ELECTROMECHANICAL CLOCKS OR WATCHES
- G04C10/00—Arrangements of electric power supplies in time pieces
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
Abstract
The invention relates to an electric low-power supply system for devices, in particular wearable, portable or moving devices, such as watches, in particular 5 smartwatches, wearable sensors and sensors on moving objects. The invention also relates to a device, in particular a wearable, portable or moving device, such as a watch, in particular a smartwatch, or a sensor, comprising a low-power supply system according to the invention.
Description
The invention relates to an electric low-power supply system for devices, in particular wearable, portable or moving devices, such as watches, in particular smartwatches, wearable sensors and sensors on moving objects. The invention also relates to a device, in particular a wearable, portable or moving device, such as a watch, in particular a smartwatch, or a sensor, comprising a low-power supply system according to the invention.
Energy harvesting devices creating electrical energy from (human) wrist movement exist for a long period of time. Typically these systems use an eccentric weight which moves when the position of the system changes in relation to the direction of gravity. The moveable eccentric weight usually drives a magnetic rotor of an electromagnetic generator through a train of gears. To improve the system’s energy output and efficiency, especially at moderate movements, some of these systems use a small micro-spring downstream the accelerating gear train to accelerate the rotor of the electromagnetic generator. The mechanical spring stores the energy of the eccentric weight, until the torque in the micro-spring has reached a certain level, high enough to achieve sufficient acceleration of the magnetic rotor.
However, the energy harvested by the known systems is limited, and too limited for powering more demanding electronic devices, such as smartwatches, which limits the applicability of the known solution. Moreover, the micro-spring requires a relatively large spring tension angle, which makes the micro-spring unsuitable for bi-directional tensioning without deforming the spring permanently and without damaging the spring, both during normal use and in particularly during shocks or overload conditions. Additionally, to enable this vulnerable micro-spring to function properly, an assembly of many complex micro mechanical components, like mechanical rectifiers, is needed, which makes the known system as such relatively complex and expensive.
It is a first object of the invention to provide an improved low-power supply system by means of which one or more of the aforementioned drawbacks can be overcome.
It is a second object of the invention to provide a less vulnerable low-power supply system.
It is a third object of the invention to provide a low-power supply system which can be manufactured in a less complex and/or less expensive manner.
It is a fourth object of the invention to provide a low-power supply system configured to generate more electrical energy per unit of time.
To this end, the invention provides a low-power supply system according to the preamble, comprising: at least one electrical generator, comprising a rotor wheel being coupled to a driven shaft and having magnetized poles, a stator having a (coil with a) plurality of windings for providing an electric voltage; at least one eccentric oscillatory weight for driving the driven shaft of at least one generator upon movement of the oscillatory weight, at least one transmission structure connecting at least one oscillatory weight and the driven shaft of at least one generator, said transmission structure comprising: at least one primary transmission wheel directly and/or indirectly co-acting with the driven shaft of at least one generator, and at least one torsion spring having a first end portion and an opposite second end portion, wherein the first end portion of the torsion spring is directly engaging and/or co-acting with at least one oscillatory weight, and wherein the opposite second end portion of the torsion spring is directly engaging and/or co-acting with the primary transmission wheel, for providing a resilient transmission between said oscillatory weight and said primary wheel. The resilient transmission increases the energy output of the system and/or protects the transmission structure, including all parts directly and/or indirectly attached or connected to the transmission structure, i.e. oscillatory weight, rotation shaft, primary transmission wheel, bearings, other gears and the driven shaft, against shocks and overload conditions which occur during use of the system.
The system according to the invention comprises a spring which directly engages, and is preferably connected to, the eccentric oscillatory weight (also referred to as eccentric mass) and the primary transmission wheel, and hence at a distance from the generator(s). The torsion spring is positioned in between the eccentric oscillatory weight and the primary transmission wheel, meaning that the torsion spring, either directly or indirectly, connects at least one eccentric oscillatory weight with at least one primary transmission wheel. Moreover, since in between the primary transmission wheel and the driving shaft of the generator typically one or more secondary transmission wheels are positioned in order to drive and to accelerate the driven shaft of the generator, the torsion spring is positioned upstream with respect to all transmission wheels. This positioning has multiple advantages. First of all, the upstream position of the torsion spring allows to apply a torsion spring with a relatively small spring tension angle and a co-related relatively high torque, compared to conventional downstream micro-springs, which allows the torsion spring to be designed in a more simple and more robust manner, which makes the torsion spring less complex, less vulnerable and less expensive. Moreover, since the torsion spring as used in the system according to the invention works with a relatively small spring tension angle, the torsion spring as used in the system according to the invention can be used bidirectionally. This means that the torsion spring is configured to temporarily store spring energy both by winding and unwinding of the torsion spring, dependent on the displacement direction of the eccentric oscillatory weight during an orientation change and under the influence of gravitational or dynamic forces. Moreover, due to the bidirectional operation of the torsion spring, combined with the relatively small spring tension angle, the system according to the invention is configured to generate more power than the conventional systems. However, the power generated by means of the system according to the invention is still qualified low-power, which is typically in the order of magnitude of several microwatt to 1 Watt.
In addition to the aforementioned advantages, the system according to the invention can be constructed in a relatively simple and compact manner, which makes it ideally suitable to be incorporated in power consuming miniature devices. The low-power supply system is arranged for converting kinetic energy into electric energy for the benefit of these power consuming miniature devices. The system according to the invention may be used as an electric power source in various electronic devices which are in motion during normal use. Watches, smart watches, sensors, pacemakers, and electric circuits implanted in animals or persons, e.g. for registration, identification, and/or monitoring purposes, are examples of such devices. The electric power generated by the system may be used as well as to power an activity tracker for a person or animal.
The oscillatory weight and the primary transmission wheel are typically mounted coaxially. The torsion spring is typically positioned in between said weight and said primary transmission wheel. Preferably, the torsion spring is also coaxially mounted with respect to both the oscillatory weight and the primary transmission wheel. The oscillatory weight and the primary transmission wheel are preferably mutually rotatable, and more preferably substantially freely rotatable. In particular, in case the torsion spring is in an initial unloaded state, an initial rotation of the oscillatory weight will not directly result in a rotation of the primary transmission wheel, but rather in a deformation of the torsion spring, wherein spring energy is stored in the torsion spring, until the spring energy (and/or spring tension angle and/or spring torque) will reach a predetermined level, after which the spring energy will be transferred to the primary transmission wheel causing rotation and typically also acceleration of the transmission wheel. Hence, during normal use a resilient transmission is present between said oscillatory weight and said primary transmission wheel.
Commonly, the system comprises at least one support structure for mounting the at least one generator, the at least one oscillatory weight and the transmission structure, and optional other components which are used in the system. The support structure may comprise a supporting plate and/or may be composed of a plurality of mounting components.
The oscillatory weight preferably comprises a rotation shaft (axle) extending in the direction of the primary transmission wheel. This rotation shaft is preferably used to stabilize the eccentric weight. To this end, it is preferred that a portion, preferably a terminal portion, of the rotation shaft co-acts with a bearing mounted by the support structure. This commonly stabilizes the rotation shaft and hence the eccentric weight as such. Also, the rotation shaft is typically used to support, preferably as a kind of bearing, the primary transmission wheel and - if applied - the (inner spring) bush which is preferably connected to, or which is part of, the primary transmission wheel. To this end, it is preferable that at least a part of the rotation shaft of the eccentric oscillatory weight is enclosed by at least one (bearing and spring) bush, wherein said (bearing and spring) bush is at least partially enclosed by the torsion spring., This commonly, delimits the lateral movement of the torsion spring to the inward direction. More preferably, said at least one bush, in particular a bearing and/or spring bush, is connected, preferably rigidly connected to, or being part of, the primary transmission wheel.
To limit the lateral movement and/or deformation of the torsion spring in the outward direction the eccentric weight preferably comprises an (outer spring) bush, wherein said (outer spring) bush at least partially encloses the torsion spring. This commonly, delimits the lateral movement of the torsion spring to the outward direction. More preferably, said at least one bush is connected, preferably rigidly connected to, or being part of, the primary transmission wheel.
It is thinkable, that preferably a part of preferably the inner and/or outer spring bush is/are connected to, and/or is/are part of, the primary transmission wheel and/or eccentric weight. Various combinations are imaginable in this respect.
Typically, the outer diameter of the inner spring bush is smaller than the inner diameter of the torsion spring. This results in the situation that a (limited) free space is present between the bush and the torsion spring (at least in unloaded state). This prevents that winding of the torsion spring is hindered or blocked by the bush during normal use. Winding of the torsion spring leads to a decrease in spring diameter. Preferably, the maximum distance between wherein the outer diameter of the spring bush and the inner diameter of the torsion spring, in unloaded state, is 2 millimetre, and more preferably 1 millimetre. The torsion spring is preferably configured to rigidly engage an outer surface of the inner spring bush after exceeding a predefined spring protection angle and/or predefined spring protection torque Hence, in abnormal situation, for example in case of a shock or a load exceeding the predefined (maximum) load, the spring is protected by changing the initial resilient coupling between the eccentric weight and the primary transmission wheel into a (temporary) rigid coupling. Here, the inner spring bush prevents the torsion spring to deform excessively, which is in favour of the durability of the torsion spring, and hence of the system as such. In a particular preferred embodiment, said predefined spring protection angle is situated in between +5 and +90 degrees, and is preferably about +40 degrees. In a particular preferred embodiment, said predefined spring protection torque is situated in between +0,3 and +2 mNm, and is preferably about +1.6 mNm.
Typically, the outer spring bush is part of the oscillatory weight or connected to the oscillator weight and encloses at least a part of the torsion spring. More preferably, the inner diameter of a part of the outer spring bush enclosing the torsion spring at least partially is larger than the outer diameter of the torsion spring. This also creates a limited free space around the torsion spring (in unloaded state). This prevents that unwinding of the torsion spring is hindered or blocked by the eccentric weight during normal use. Unwinding of the torsion spring leads to an increase in spring diameter. Preferably, the maximum distance between the outer diameter of the torsion spring and the inner diameter of the part of the eccentric weight enclosing said torsion spring, in unloaded state, is 2 millimetre, and more preferably 1 millimetre. In a preferred embodiment, the torsion spring is configured to rigidly engage an inner surface of the outer spring bush (being part of or being directly connected to the oscillatory weight) enclosing the torsion spring after exceeding a predefined spring protection angle and/or predefined spring protection torque. Hence, in abnormal situations, for example in case of a shock or a load exceeding the predefined (maximum) load, the spring is protected by changing the initial resilient coupling between the eccentric weight and the primary transmission wheel into a (temporary) rigid coupling. Here, the outer spring bush prevents the torsion spring to deform excessively, which is in favour of the durability of the torsion spring, and hence of the system as such. In a particular preferred embodiment, said predefined spring protection angle is situated in between -5 and -90 degrees, and is preferably about -40 degrees. In a particular preferred embodiment, said predefined spring protection torque is situated in between -0,3 and -2 mNm, and is preferably about -1.6 mNm.
Another advantage of the above mentioned transmission structure us that it can be beneficial for increasing the electrical output of the system by defining the maximum spring tension angles and related lateral movements, in preferably both directions, and ensure or prevent the rigid coupling to occur depending on the type of movement of the system.
As mentioned above, the transmission structure is configured to store spring energy into the torsion spring during deformation of the torsion spring as a result of displacement of the oscillatory weight. And preferably, the transmission structure is configured to store spring energy into the torsion spring both during winding and unwinding of the torsion spring as a result of displacement of the oscillatory weight. The transmission structure is preferably configured to transfer spring energy stored in the torsion spring to the primary wheel, after exceeding a predefined spring tension angle and/or predefined spring torque. Said predefined spring tension angle is typically situated (during winding) in between +5 and +90 degrees, and is preferably about +10 degrees, and/or (during unwinding) in between -5 and -90 degrees, and is preferably about -10 degrees. Said predefined spring torque is typically situated (during winding) in between +0.15 and +0.9 mNm, and is preferably about +0.45 mNm, and/or (during unwinding) in between -0.15 and -0.9 mNm, and is preferably about -0.45 mNm.
In a preferred embodiment, the at least one transmission structure comprises at least one accelerating secondary transmission wheel, and preferably a gear train of accelerating secondary transmission wheels, connecting the primary wheel and the driven shaft of at least one generator. This gear train will lead to an acceleration of the rotation speed of the driving shaft, and hence of the rotor, of the generator, leading to an increased power density per unit of time and/or a higher voltage level and/or to the required use of a smaller, less expensive generator. Preferably, at least one secondary transmission wheel is formed by a compound gear including a small diameter gear and a large diameter gear mounted on a common shaft.
The torsion spring typically comprises a substantially cylindrical central body part. And preferably, the first end portion and/or the second end portion protrude(s) laterally with respect to said substantially cylindrical body part of the torsion spring. These end portions are optionally straight (linear), which facilitates engagement of these end portions by the eccentric oscillatory weight and the primary transmission wheel, respectively. The central body part of the torsion spring is typically formed by a helically wound wire. Preferably, the diameter of the wire is situated in between 0.1 and 0.9 millimetre, and is preferably about 0.3 millimetre. The number of windings of the wire is preferably situated in between 2 and 5. The outer diameter of the central body part of the torsion spring is preferably situated in between 4 and 6 millimetre. The aforementioned values indicate that the torsion spring is relatively large and less vulnerable compared to known micro-springs. The torsion spring is typically made of metal, in particular spring steel, and/or at least one polymer material.
Preferably, the stator of at least one generator comprises a field winding which is arranged in the axial direction outside the radial projection of the rotor, and clawpole-like magnetoconductive sheets, preferably between 10 and 20 sheets, guided axially in the radial projection of the rotor. The rotor is preferably at least partially surrounded by the stator.
Preferably, at least one generator is electrically connected to at least one AC voltage to DC voltage rectifying and/or storing circuit. This is beneficial to supply DC energy to an electronic system directly and/or indirectly by storing the generated electrical energy into at least one electrical energy storage of the system, such as a battery or capacitor, connected, either directly or indirectly (via the rectifying and/or charging circuit), to at least one generator for storing electrical energy generated by said at least one generator.
The invention also relates to a device, in particular wearable, portable or moving devices, such as watches, in particular smartwatches, wearable sensors and sensors on moving objects, comprising at least one low-power supply system according to the invention. Other examples of suitable devices have been given above. Preferably, the device comprises at least one control unit powered by the at least one low-power supply system. The system according to the invention, when applied in a (smart)watch is configured to generate a daily electrical energy of about 1,2 Joule (during normal) use, which is three times higher than the electrical energy that can be harvested by using conventional, known mechanisms. This increased amount of energy allows the system to power high-energy demanding devices, like smartwatches, while that was and is not be possible with the known (ultra-)low-power supply systems.
In order to further elucidate the invention, a number of exemplary, non-limitative embodiment will be described with reference to the following figures, wherein:
- figure 1 shows a transparent perspective view on an electric low-power supply system according to the invention,
- figure 2 shows a transparent top view on the electric low-power supply system of figure 1, and
- figure 3 shows a cross-section of a centre part of the electric low-power supply system of figures 1 and 2.
Figure 1 shows a transparent perspective view on an electric low-power supply system 1 according to the invention. Further, figure 2 shows a transparent top view on the electric low-power supply system of figure 1. Between the figures, similar features are referred to by similar reference numbers. As may be seen from both figure 1 and figure 2, the system 1 comprises an eccentric oscillatory weight 2 that is able to rotate around a rotation shaft 3 fixedly connected to the eccentric oscillatory weight 2. The rotation shaft 3 is extending in the direction of a primary transmission wheel 4 and is partly enclosed by a spring bush 5 that is fixedly connected to the primary transmission wheel 4. The inner spring bush 5 is furthermore enclosed by a torsion spring 6 that is on a first end portion 7 directly engaging the oscillatory weight 2 and on a second end portion 8 directly engaging the primary transmission wheel 4. The eccentric oscillatory weight 2 is hereby connected to the primary transmission wheel 4 and the spring inner spring bush 5 through a resilient transmission formed by the torsion spring 6. The primary transmission wheel 4 is through toothing provided on its outer circumference connected to a series of two accelerating secondary transmissions wheels 9, 10. Each of said secondary transmission wheels 9, 10 is formed by a compound gear including a small diameter gear 11,12 and a large diameter gear 13, 14 mounted on a common shaft 15,16. The primary transmission wheel 4 hereby engages the small diameter gear 11 of the first of the accelerating secondary transmission wheels 9. The large diameter gear 13 of the first of the accelerating secondary transmission wheels 9 on its turn engages the small diameter gear 12 of the second of the accelerating secondary transmission wheels 10. The large diameter gear 14 of the second of the accelerating secondary transmission wheels 10 subsequently engages a gear 17 fixedly connected to a driven shaft 18 of an electrical generator 19. The electrical generator 19 comprises a rotor 20 wheel that is coupled to the driven shaft 18, as well as a stator 21 surrounding the rotor 20. The electrical generator 19, the eccentric oscillatory weight 2 and the transmission structure including the primary and secondary transmission wheels 9,10, the spring bush 5 and the torsion spring 6 are all directly or indirectly supported by a support structure 22. Moreover the eccentric oscillatory weight 2 is separated from the rest of the system's components through a housing plate 23. The eccentric oscillatory weight 2 is hereby able to move freely relative to the housing plate 23 through the application of a bearing 27 (see figure 3) provided between the eccentric oscillatory weight and the housing plate 23. The housing plate 23 is connected to the support structure 22 by a number of connecting means 24. Along the circumference of the housing plate 23, an assembling ring 25 is provided for connecting the system to an external housing or watch casing (not shown here).
Figure 3 shows a cross-section of a centre part of the electric low-power supply system 1 of figures 1 and 2 taken along line A-A as shown in figure 2. Structural elements similar to those in figures 1 and 2 are herein referred to with similar reference numbers. Again, the eccentric oscillatory weight 2 can be seen, being fixedly connected to the rotation shaft 3. The rotation shaft 3 is at a terminal portion thereof mounted, in a rotationally way, on the support structure 22 with the interposition of a bearing 26, which ensures the stability of the rotation shaft and enables the assembly of the inner spring bush and the primary transmission wheel. Provided around the rotation shaft 3 and being able to rotate relative to said rotation shaft 3 is the inner spring bush 5. The spring bush 5 is on its turn enclosed by the torsion spring 6, as well as fixedly connected to the primary transmission wheel 4. The outer diameter of the spring bush 5 is chosen such that a space is left between the torsion spring 6 and the spring bush 5 in unloaded state of the torsion spring 6. When the diameter of the torsion spring 6 is however sufficiently reduced through the application of a torsional moment on the torsion spring, the torsion spring 6 will rigidly engage the outer surface of the inner spring bush 5. In this case a non-resilient connection between the eccentric oscillatory weight 2 and the primary transmission wheel 4 is established through the torsion spring 6. In a similar fashion, the primary transmission wheel 4 and the outer spring bush, being part of or directly connected to the eccentric oscillatory weight 2 encloses the torsion spring 6, thereby leaving a space between the torsion spring 6 and the eccentric oscillatory weight 2 respectively the primary transmission wheel 4 in unloaded state of the torsion spring 6. When the diameter of the torsion spring 6 is sufficiently increased through the application of a torsional moment on the torsion spring 6, the torsion spring 6 will rigidly engage the inner surfaces of the eccentric oscillatory weight 2 and the primary transmission wheel 4. This again leads to a non-resilient connection between the eccentric oscillatory weight 2 and the primary transmission wheel 4. Figure 3 moreover shows that the eccentric oscillatory weight 2 is separated from the rest of the system’s components through a housing plate
23, wherein a bearing 27 is provided between the eccentric oscillatory weight 2 and the housing plate 23.
It will be apparent that the invention is not limited to the exemplary embodiments shown and described here, but that within the scope of the appended claims numerous variants are possible which will be self-evident to the skilled person in this field. It is possible here to envisage that different inventive concepts and/or technical measures of the above described embodiment variants can be wholly or partially combined without departing from the inventive concept described in the appended claims.
The verb “comprise” and conjugations thereof used in this patent publication are understood to mean not only “comprise”, but are also understood to mean the phrases “contain”, “substantially consist of”, “formed by” and conjugations thereof. 15
Claims (39)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2021361A NL2021361B1 (en) | 2018-07-20 | 2018-07-20 | Electric low-power supply system for devices and device comprising such a low-power supply system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2021361A NL2021361B1 (en) | 2018-07-20 | 2018-07-20 | Electric low-power supply system for devices and device comprising such a low-power supply system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| NL2021361B1 true NL2021361B1 (en) | 2020-01-29 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NL2021361A NL2021361B1 (en) | 2018-07-20 | 2018-07-20 | Electric low-power supply system for devices and device comprising such a low-power supply system |
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| NL (1) | NL2021361B1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11990823B2 (en) | 2021-05-14 | 2024-05-21 | Rain Bird Corporation | Self-powered irrigation systems, generator systems and methods of controlling irrigation |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020071348A1 (en) * | 2000-12-07 | 2002-06-13 | Eta Sa Fabriques D'ebauches | Anti-shock transmission device for driving a generator by an oscillating weight in particular in a watch |
| US6441516B1 (en) * | 1999-09-17 | 2002-08-27 | Eta Sa Fabriques D'ebauches | Shockproof device for a power generator with an oscillating weight |
-
2018
- 2018-07-20 NL NL2021361A patent/NL2021361B1/en active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6441516B1 (en) * | 1999-09-17 | 2002-08-27 | Eta Sa Fabriques D'ebauches | Shockproof device for a power generator with an oscillating weight |
| US20020071348A1 (en) * | 2000-12-07 | 2002-06-13 | Eta Sa Fabriques D'ebauches | Anti-shock transmission device for driving a generator by an oscillating weight in particular in a watch |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11990823B2 (en) | 2021-05-14 | 2024-05-21 | Rain Bird Corporation | Self-powered irrigation systems, generator systems and methods of controlling irrigation |
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