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The present invention relates to a generator comprising an inner circuit and an outer circuit.
The present invention relates to a bicycle lighting system comprising a dynamo system drivable by a ridden bicycle and mounted thereat, at least one front light or headlamp and at least one rear light or tail lamp, both of which are supplied with electric power from the dynamo system, and a converter arrangement which converts the electric power produced by the dynamo system into a regulated direct-current voltage for the purpose of generating light and charging an accumulator or storage battery. The invention also relates to a generator for general applications, particularly however for use as a bicycle dynamo generator.
Conventional and marketable bicycle lighting systems have to comply, with respect to the electric pbwer and voltage, with the Standards determined by law. At a traveling speed of 15 kilometers per hour and beyond that, these Standards specify a maximum voltage of 7 V for the dynamo output voltage applied at the lamps. In accordance with legal regulations, the minimum value of the output voltage of the dynamo lies between 3 V at 5 kmph and 5.8 V at 15 kmph and - as indicated in Figure 5a of the annexed drawings - must not fall short of 5.8 V at a speed beyond or better than 15 kmph. On the basis of the aforementioned regulations, present-day or state-of-the-art dynamos allow producing merely 1.4 W power at a bicycle traveling speed of 5 to 6 kmph. If such power or output of present-day conventional dynamos is increased, i-t would be physically impossible to meet or observe the legally specified maximum voltage of 7 V at 15
kmph or beyond such speed. Only by taking respective load measures would it be possible to prevent exceeding the legally specified maximum value. As a result, the power dissipation or loss would greatly increase and the efficiency would considerably decrease.
Therefore, conventional bicycle lighting systems cannot be additionally loaded in the lower speed range for the purpose of charging an accumulator or storage battery. Only when the traveling speed is at least approximately 15 kmph, conventional dynamos will generate sufficient power that could be used for charging an accumulator battery, the efficiency of these known systems being far too low when the traveling speed is below the aforementioned speed of 15 kmph. Laterally mounted dynamos have an efficiency of approximately 17% to 24%, roller dynamos can achieve an efficiency of 30% to 35% at the most, and the efficiency of hub dynamos is approximately 40%. When the traveling speed of the bicycle exceeds 15 kmph, the efficiency additionally decreases because of the power draw or consumption while charging the accumulator battery. Under such circumstances, the bicycle rider is obliged to expend additional physical energy for actuating the dynamo.
Those skilled in the art have criticized the aforementioned limitations and drawbacks of prior-art constructions and have realized that conventional dynamos and bicycle lighting systems do not correspond at all with the state of present-day engineering knowledge.
Therefore, with the foregoing in mind, it is a primary object of the present invention to provide a new and improved construction of a bicycle lighting system in combination with a
generator, which system is adapted to the latest state of advanced engineering and technology and accommodated to present-day requirements.
Another significant object of the present invention is directed to the provision of a new and improved bicycle lighting system which is relatively simple in construction and design and, particularly, economical to manufacture.
Yet a further significant object of the present invention is concerned with a new and improved dynamo system, which - with regard to construction, power efficiency and production cost thereof - meets all requirements of the bicycle lighting system of the present invention.
The implementation of these and further objects of the present invention is based on the finding and conclusion that a satisfactory bicycle lighting system can only be realized by means of a dynamo generator having an efficiency considerably higher than that of conventional dynamos.
The bicycle lighting system of the present development is characterized in that the dynamo system comprises a dynamo generator which is arranged and constructed such, that - from a minimum traveling speed of about 5 to 7 kmph - it generates an electric power adequate to charge the battery and simultaneously feed the front light and the rear light, and that the converter arrangement comprises an upward and downward converting function and is additionally fed by the battery as long as the traveling speed falls short of the minimum traveling speed.
In a preferred embodiment of the dynamo system according to the present invention, the converter arrangement comprises an
energy-converter and energy-limiter device and a threshold-value device detecting a rectified dynamo output voltage, whereby in case the threshold-value device detects that a predetermined minimum voltage of the dynamo generator is exceeded, the voltage supplied from the battery is fed - in addition to the rectified dynamo output voltage of the dynamo generator - by means of an electronic switchgear to the energy-converter and energy-limiter device, and whereby the output voltage of the energy-converter and energy-limiter device lies within a first constant output voltage range Ua^ during battery operation and within a second constant output voltage range Ua2 during dynamo operation, the latter range lying above the first constant output voltage range Uai, and a battery charging device is activated above an output charging voltage which lies between the first constant output voltage range Ua^ and the second constant output voltage range Ua2 (refer to Figures 5a, 5b and 5c of the annexed drawings).
The first constant output voltage range Uai of the converter arrangement preferably lies within a fixedly set range from 4.5 V to 6 V. During this mode of operation, the input voltage range of the converter lies between 0.8V minimum threshold-value voltage and a maximum switch-over voltage of 4.8 V.
The second constant output voltage range Ua2 of the converter arrangement preferably lies within a range between 6.2 V and 7 V, but advantageously above 6.4 V. During this mode of operation, the input voltage range of the converter lies in an initial speed range between approximately 5 V and 6 V and increases up to maximum 80 V at a speed of about 80 kmph (refer to Figures 5a and 5c of the annexed drawings). By virtue of this setting of the converter arrangement in accordance with the teachings of the present invention, the legal requirements
and Standards are perfectly met at each and every speed. The combination of the high-efficiency dynamo generator with the converter arrangement and the accumulator battery renders possible a combined battery-charging, standing-light and traveling-light system. The converter arrangement is operated by the battery as well as directly by the dynamo generator.
The energy-converter and energy-limiter device preferably limits the output of the converter arrangement invariably between 4 W and 6 W, advantageously between 4.5 W and 5 W. In this manner, the short-circuit safety of the battery and of the dynamo generator as well as of the entire dynamo system is also ensured.
According to a particularly preferred embodiment of the present invention, the converter arrangement further comprises (a) a rectifier circuit for the purpose of producing the rectified and smoothed dynamo output voltage which is fed to the energy-converter and energy-limiter device, (b) a first voltage divider network for the purpose of converting a first rectified and speed-proportional output voltage of the dynamo generator into a first component voltage and supplying such first component voltage to a first threshold-value switch, (c) a second voltage divider network for the purpose of converting the rectified and speed-proportional output voltage of the dynamo generator into a second component voltage and supplying such second component voltage to a second threshold-value switch, whereby the first threshold-value switch supplies the battery voltage to the energy-converter and energy-limiter device by means of the electronic switchgear when the rectified output voltage of the dynamo generator exceeds a first threshold voltage detected by the first threshold-value switch, and whereby the second threhold-value switch supplies a signal to
the energy-converter and energy-limiter device for switching over the output voltage of the latter from the first constant output voltage to the second constant output voltage, and vice versa, whenever the second threshold-value switch detects that a second threshold voltage is not reached or is exceeded, (d) a delay circuit connected to the output of the first threshold-value switch and with the electronic switchgear and which, in case the rectified output voltage of the dynamo generator falls short of the first threshold voltage, opens the electronic switchgear at the end of a predetermined period of time, e.g. four minutes, for the purpose of switching off the voltage of the battery from the input of the energy-converter and energy-limiter device, and (e) a battery charging converter which is coupled at the output side thereof with the energy-converter and energy-limiter device and which, in the case of battery operation, also remains activated for charging the battery.
The first threshold-value switch switches on the battery voltage at a threshold voltage Vx of approximately 0.8 V by means of the electronic switchgear.
The battery charging converter operates at an output voltage Ua of 6.1 V up to a maximum of 7 V, such output voltage Ua proportionally increasing with higher power conversion in dependence on the charging condition of the battery.
In order to ensure the required characteristic features and properties of the dynamo system, there are provided a dynamo generator having a high efficiency and comprising a very low coil internal resistance and which - already at a low speed of approximately 5 to 7 kmph - produces an output of at least 4.5 W at a relatively low output voltage, and a converter arrangement
which converts the aforesaid output of the dynamo generator into an output voltage of 6.2 V to 7 V. In order to achieve the high efficiency, the dynamo generator comprises an inner circuit and an outer circuit as illustrated in Figures la and Ib of the annexed drawings, both of which are mounted for synchronous rotation in the same direction about a stationary air-core coil, whereby the inner circuit and the outer circuit comprise in each case n poles in identical pole pitch.
Owing to the fact that an inner circuit and an outer circuit can synchronously rotate in the same sense of rotation about a stationary air-core coil, there is achieved - in conjunction with the application of progressive powerful magnets as well as by virtue of an extremely low internal resistance of the coil, which is preferably lower than 1.5 ohms - a high field strength together with the advantage of a comparatively small iron-and-magnet volume and very low magnetic or hysteresis losses. The actually effective magnetic circuit consists of two partial circuits MK1 and MK2 as depicted in Figure Ib of the annexed drawings.
The inner circuit comprises n (preferably six by way of example) inner pole shoes, and at each inner pole shoe there are laterally arranged two magnetic poles in homopolar configuration. In this manner, the two magnetic surfaces project themselves upon the pole-shoe surface (b^ in Figure la). Since the two magnetic surfaces are preferably far larger than the pole-shoe surface, the density of the magnetic flux correspondingly increases toward the pole-shoe surface.
Furthermore, this arrangement is advantageous in that the pole shoes or pieces (
substantial weight reduction. The magnetic flux is apportioned via the outer circuit in two parts or portions directed onto the oppositely situated outer pole shoes or pieces (g-m in Figure Ib).
The outer circuit likewise comprises n (preferably six by way of example) outer pole shoes which are oppositely arranged relative to the inner pole shoes and nose-shapedly projecting toward the latter, these outer pole shoes being structured such that each air gap between the inner pole shoes and the respective outer pole shoes assigned to the latter is the shortest path for the magnetic flux as depicted in Figures la and Ib of the drawings by reference characters MKl, MK2 and 30. In this manner, the magnetic leakage flux is advantageously reduced.
In order to reduce the mutual interference of the homopolar magnets, each inner pole shoe is divided in the middle or mid-portion thereof into two identical parts by a slot producing an air gap and extending in the radial direction. This arrangement results in the notable advantage of a smaller pole-shoe volume as well as larger magnet heights or, in other words, two half magnet-lengths per pole together with the smallest magnet-volume and the double magnet-surface are rendered possible.
The air gap in the inner pole shoes reduces the mutual interference of the two homopolar magnet faces, because the magnetic flux glides in each case with respective halves over the pole shoe to the outer circuit. The two magnetic fluxes in each inner pole shoe possess an optimally short magnetic circuit path, so that the result is an optimal magnetic flux. A further advantage is seen in the fact that an extremely small generator
with very high flux densities can be produced, such generator having at the same time a light-weight, small magnet-volume and high-efficiency structure. The efficiency achievable by means of the new and improved dynamo generator provided for the bicycle lighting system constructed according to the present invention is at least approximately 90%.
By way of example, the thereby resulting actual efficiency of the entire bicycle lighting system constructed in accordance with the teachings of the present invention for 3 W luminous power and 1 W battery charging energy is - with reference to 3 W - approximately 60% in the case of a discharged accumulator battery and approximately 80% when the accumulator battery is charged.
Advantageously, the air-core coil possesses a very low inductance, i.e. lower than 150 uH, preferably lower than 100 p.E. In this manner, there is produced a negligible mutual or counter inductance, whereby the pole sensitivity is hardly or not at all noticeable while, at the same time, the induction losses are extremely low.
Preferably, the air-core coil is divided per pole field into two identical coil sections which are pole-correctly connected in series (23.1 to 23.6 in Figure 2a).
As alluded to above, the invention is not only concerned with the aforementioned bicycle lighting system, but also relates to the new and improved construction of the generator. Those skilled in the art will readily understand that the underlying principles and concepts of the dynamo generator can be also employed for other generator applications.
The characteristics of the magnet arrangement and of the magnetic circuit structure can be advantageously applied to and used for electric motors, for instance, servomotors.
The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein throughout the various figures of these drawings, there have been generally used the same reference characters to denote the same or analogous components and wherein:
Figure la is an enlarged detail showing of a part of a cross-sectional view of a dynamo generator illustrated in Figure Ib;
Figure Ib shows a cross-sectional view of a preferred exemplary embodiment of the dynamo generator constructed in accordance with the present invention;
Figure 2a shows the inner magnetic circuit arrangement in a perspective cross-sectional illustration;
Figure 2b shows the arrangement of the stationary coil in a stretched illustration of the coil arrangement;
Figure 3 schematically shows a block diagram of a preferred exemplary embodiment of the bicycle lighting system constructed according to the present invention whereby, in particular, the role of the proposed converter arrangement becomes apparent;
Figure 4a shows a voltage + speed/variation-in-time diagram and Figures 4b, 4c, 4d and 4e depict voltage/time diagrams for the purpose of explaining the function of the bicycle lighting system according to the present invention;
Figures 5a, 5b and 5c show voltage/speed diagrams to further explain the function of the inventive dynamo system, whereby Figure 5a depicts operation with a discharged or defective battery and Figure 5c refers to operation with a normal functioning battery;
Figure 6 shows an exemplary accomplished embodiment of the circuit arrangement of the bicycle lighting system constructed according to the present invention and realized by means of a customized solid-state integrated switching circuit (ASIC);
Figure 7 shows a longitudinal sectional view of a first exemplary embodiment of the dynamo system constructed according to the present invention and structured as a laterally mounted bicycle dynamo; and
Figure 8 shows a longitudinal sectional view of a second exemplary embodiment of the dynamo system constructed according to the present invention and structured as a roller bicycle dynamo.
Turning attention now specifically to Figures la and Ib of the drawings, a dynamo generator 1 illustrated therein by way of example and not limitation will be seen to comprise in concentric arrangement from the center to the circumference a rotating inner circuit 21, a stationary air-core coil 23 and an outer circuit 22 synchronously rotating with the inner
circuit 21. In the exemplary embodiment depicted in Figures la and Ib, the inner circuit 21 and the outer circuit 22 each comprise six poles in identical pole pitch, the poles of the inner circuit 21 thereby facing the respective poles of the outer circuit 22, so that the resulting pole-pitch angle is 60°. The six poles of the inner circuit 21 are structured in the form of six pole shoes a., b, c_, d, e_ and f_, while the poles of the outer circuit 22 are likewise structured in the form of six pole shoes g_/ h» i/ ]$./ i anc^ 51' which are situated opposite to the pole shoes a-f and which nose-shapedly project toward the latter, so that the smallest possible air gap 30 is formed. The pole shoes a-f of the inner circuit 21 are made of soft iron, while the carrier or support of the inner magnetic circuit is itself non-ferrous. The outer circuit 22 consists entirely of soft iron. The number of poles, namely six, is specified only by way of a preferred example.
Between the six pole shoes a-f of the inner circuit 21 there are arranged six permanent magnets 24-29 in such a manner that in each case they rest homopolar against both sides of each pole shoe. The result is that the two magnet surfaces, which in Figure la are designated by reference characters a^ and 3^2 (magnet width) at the respective magnets 24 and 29, project themselves upon a pole-shoe surface bi of the respective pole shoe f_. The magnet lengths M]_ (refer to Figure 2a) of the permanent magnets 24-29 extending perpendicularly with respect to the illustration in. Figures la and Ib and the entire arrangement are determined such, that in each case the sum of the respective magnet surfaces a-^ and a.2 is far larger than the respective pole-shoe surface bj. In this manner, the magnetic-flux density correspondingly increases toward the pole-shoe surface b-^. This arrangement is furthermore advantageous in that the six pole shoes a-f of
the inner circuit 21 possess a relatively small mass, so that a substantial weight reduction is rendered possible.
However, the entire rotating portion of the dynamo generator 1 possesses, mainly because of the rotating outer circuit 22, a relatively high moment of inertia, so that the wheel slippage behavior is substantially improved.
The magnetic flux from the pole shoes a-f of the inner circuit 21 is divided across the respective nose-shapedly projecting pole shoes g-m of the outer circuit 22 into two parts or portions as illustrated in Figure Ib and designated by the reference characters MK1 and MK2. By virtue of the nose-shaped form of the pole shoes g-m of the outer circuit 22, such form being also adapted to the periphery of the coil, there results the air gap 30 - indicated between a pole-shoe pair, namely the pole shoes f_ and m in Figure la ..- as the shortest path for the magnetic flux. The magnetic leakage flux is thus reduced.
In order to reduce interaction of the homopolar magnets 24-29 resting against both sides of the respective pole shoes a-f of the inner circuit 21, these pole shoes a-f are provided each with a slot in the mid-portion thereof, such slots forming radial air gaps 31-36. The advantage of this arrangement is seen in a small pole-shoe volume with large magnet heights at the same time, i.e. two magnet widths per pole with, at the same time, the smallest possible magnet volume and the double magnet surface.
These radial gaps 31-36 provided in the pole shoes a-f prevent interaction of the two homopolar magnet-face surfaces, since the magnetic flux flows in halves through the respective pole shoe of the inner circuit 21 to the respective
pole shoe of the outer circuit 22. The two magnetic flux halves in each of the pole shoes a-f have an optimally short magnetic circuit path MKl and MK2 depicted in Figure Ib. The result is an optimal magnetic flux. A further advantage is that, in this manner, a relatively small dynamo generator 1 with extremely high flux density, low weight, small magnet volume, homogeneous magnetic loading and a very high efficiency can be constructed and fabricated.
Figure 2a illustrates the inner magnetic circuit as well as the coil arrangement of the preferred embodiment of the dynamo generator 1 in a perspective cross-sectional view. In Figure 2b, there is shown in a stretched or unfolded arrangement a segment of the wire-wound coil in the sequence 23.2, 23.1, 23.6 and 23.5, which together with the pole shoes b, a_, f^ and e form pole fields N3, S2 and Nl. The coil connections and two winding directions I and II of the coil sections 23.2, 23.1. 23.6 and 23.5 are schematically indicated in Figure 2b.
Since normally one coil is guided over two heteropolar poles, three coils are required for a six-polar arrangement which is not particularly illustrated in the drawings. In this manner, the stationary air-core coil arrangement 23, generally represented by reference character 23(1...6) in Figure la, is divided per pole field into two identical coil sections, so that there are six coil sections 23.1-23.6 pole-correctly connected in series. There is thus achieved a substantially smaller overall height. As depicted in Figures la and Ib, there are provided six coil sections 23.1-23.6 mutually arranged at an angular pitch of 60°.
In order to fabricate the firm and stationary air-core coil or coil arrangement 23, the windings consisting of backlack
copper wire are wound in self-contained manner and bent onto the reference circle of the air-core coil arrangement. The coils are inserted in a suitable plastic injection molding die. The mutual coil connections are already connected and mounted at a connection pin plug shown, for instance, in Figure 7 and designated by reference character 39. The plastic injection molding die includes at the same time a housing base or bottom shown, for instance, in Figure 7 and designated by reference character 37. Subsequently, the whole unit is injection molded with plastic material to form a leadless plug-in component. This type of construction renders possible that the electronic part can be plugged in directly at the housing bottom of the dynamo system. A further wiring is thus unnecessary. The wires of the stationary air-core coil have been previously processed and require no subsequent treatment or refinishing.
The process discussed hereinbefore renders possible a stationary air-core coil 23 comprising a very low inductance, i.e. preferably lower than 150 uH. In this manner, there is produced a negligible counter inductance, whereby the pole sensitivity is hardly or not at all noticeable. The coil resistance is preferably smaller than 1.6 ohms whereby, in the case of an actually accomplished construction of the dynamo generator 1, the resulting magnetic loading is larger than 0.6 T. In this realized construction the average coil diameter was 31 mm, the magnet length 30 ram and the outer diameter approximately 44 mm. The present invention aims at providing a shorter coil length of approximately 20 mm. Such coil length has been designated by reference character 40 in Figure 2b as well as in Figure 7. By virtue of this shorter coil length it is possible to also improve the essential inventive energy and power characteristics of the dynamo generator 1 constructed according to the present invention.
Having now had the benefit of the foregoing description of the dynamo generator 1 as considered with respect to Figures la, Ib, 2a and 2b, the construction and the mode of operation of the entire bicycle lighting system and particularly of a preferred embodiment of a converter arrangement 5 will be now explained by referring to Figures 3, 4 and 5.
Figure 3 illustrates a block diagram of the converter arrangement 5 of a preferred exemplary embodiment of the bicycle lighting system constructed according to the present invention. The electric alternating voltage produced by the dynamo generator 1 constructed in the foregoing described manner is rectified by a rectifier 11 and smoothed by a capacitor Cj. At a circuit node 18 there is formed the sum of a rectified dynamo voltage UeDyN and a battery voltage UBATT as will be hereinafter described. The combined voltage UeDYN and UBATT produced at the circuit node 18 is applied at the input side of an energy-converter and energy-limiter device 10 which converts this voltage/power to 6 V and 6.4 V, respectively. This energy-converter and energy-limiter device 10 possesses the characteristic feature of optimally adapting itself to the internal resistance of the dynamo generator 1. In the case of a low input voltage due to a low traveling speed, the energy-converter and energy-limiter device 10 raises the resulting voltage (power). In the case of a higher traveling speed and thus of a high output voltage and output power of the dynamo generator 1, the energy-converter and energy-limiter device 10 lowers the voltage available at the circuit node 18 to preferably 6.4 V at an output side Ua and keeps this voltage substantially constant with a variation range of approximately + 10 mV. By virtue of the provision and application of electronic components representing the latest state of the art, such as Schottky diodes and power FETs (field effect transistors), there can be achieved an efficiency of the
energy-converter and energy-limiter device 10 of 85% and even better. This efficiency is approximately 85% in the case of relatively low voltages, but can be well above 90% when there are relatively high input voltages, e.g. about 9 V, at the circuit node 18.
The overall functioning and performance of the converter arrangement 5 will be better understood when consideration is now given to the function and mode of operation of a first threshold-value switch 13, a second threshold-value switch 15 as well as a delay circuit 17 and a battery monitoring circuit 19.
First threshold-value switch 13
The output voltage of the dynamo generator 1 is rectified by means of a rectifier consisting of two diodes 03 and D^j and smoothed by a capacitor C^. This voltage Vx is proportional to the traveling speed. It is divided by means of a first voltage divider 12, which consists of two resistors R^ and R2, and supplied as voltage UT-^ to the input of the first threshold-value switch 13. This first threshold-value switch 13 activates a gate circuit T^ with an input voltage higher than Vx = 0.8 V. This means that, by means of the gate circuit T^, the voltage of a battery 4 is supplied to the summing circuit node 18 by means of a switch S^ of an electronic switchgear 16 and via a protective diode D^. A further output of the first threshold-value switch 13 sets the delay circuit 17 to zero (static).
If the input voltage at the first threshold-value switch 13 is lower than Vx = 0.8 V, the delay circuit 17 is started. The latter comprises an oscillator and counting chains
which are here not particularly illustrated. The battery voltage remains available at the summing circuit node 18 by means of the gate circuit T]_, the electronic switchgear 16 and the protective diode D]_, until the output of the delay circuit 17 opens the electronic switchgear 16 by means of the gate circuit T^. The battery voltage is then cut off. The gate circuit TI is thus activated with the first threshold-value switch 13 and moves up with the start of the delay circuit 17. In case the battery 4 is completely discharged or defective or non-existent, the activation at the circuit node 18 will be prevented by means of the battery monitoring circuit 19.
Second threshold-value switch 15
The speed-proportional voltage Vx of the dynamo generator 1 resulting at the capacitor €4 is supplied via a second voltage divider 14, which consists of two resistors R3 and R4, to the second threshold-value switch 15. The resulting input voltage is designated by reference character UT2. The second threshold-value switch 15 activates by means of an output signal the energy-converter and energy-limiter device 10 in the case of a dynamo generator output voltage lower than Vx = 4.5 V, whereby an output voltage of the energy-converter and energy-limiter device 10 of (adjustable) 4.5 V to 6 V (Ua^) is reached. If the output voltage of the dynamo generator 1 is above 4.8 V, the energy-converter and energy-limiter device 10 is set by means of the output signal of the second threshold-value switch 15 in such a manner, that the energy-converter and energy-limiter device 10 produces 6.4 V (Ua2) at the output thereof. This implies that, by virtue of the function and mode of operation of the preferred exemplary embodiment of the converter arrangement 5 depicted in Figure 3, with an input voltage UT2 of the second threshold-value switch 15 when Vx of the latter is lower than
4.5 V, voltage is procured from the battery 4 for the purpose of producing standing or parking light, and that with an input voltage Ur^ of the second threshold-value switch 15 when Vx is higher than 4.8 V, output voltage,' i.e. traveling voltage, is procured from the dynamo generator 1. The change-over from battery operation to dynamo operation occurs smoothly.
At the output of the energy-converter and energy-limiter device 10 there is connected a charging converter 20 which feeds the battery 4 as soon as the output voltage Ua exceeds 6.1V and rises up to 6.4 V by proportionally increasing in dependence on the charge condition of the accumulator battery 4. It is thereby ensured that no battery charging occurs during battery standing light operation. It is furthermore ensured that the voltage does not fall below 6 V when the energy of the dynamo generator 1 is insufficient.
At the output of the energy-converter and energy-limiter device 10 there is connected a resistance voltage divider R5, Rg which supplies a control signal U^ for the control of the output voltage Ua (feedback). This control voltage is influenced by the second threshold-value switch 15.
The functioning and mode of operation of the converter arrangement 5 schematically illustrated in Figure 3 will be discussed more fully hereinafter, particularly in conjunction with the description of Figures 4a to 4e and Figures 5a to 5c.
Figures 4a to 4e schematically show in graphical representation the chronological dependence of the voltages Uq (-Vx), UTI and UT2 (a component voltage of the voltage Vx), which are respectively produced by the first voltage divider 12 and the second voltage divider 14 and which are supplied to the first
threshold-value switch 13 and the second threshold-value switch 15, respectively. The approximately linear and speed-proportional dependence of these voltages is thereby assumed such, that they rise from zero starting at a moment of time tl(tl') up to a moment of time t3(t3') in accordance with an assumed increase in speed from zero to 30 kmph, and then again drop approximately linearly from t3(t3') to a moment of time t5(t5'). At the moment of time tl(tl')f at which the component voltage UT^ is reached with Vx = 0.8 V, the first threshold-value switch 13 is activated, and at the moment of time t5(t5') at which the aforementioned voltage UTJ falls short with Vx = 0.8 V, the first threshold-value switch 13 is deactivated (start and travel operation). Between the moments of time tl(tl') and t5(t5') the delay circuit 17 remains inactive. At the moment of time t5(t5') the delay circuit 17 starts measuring the delay of, for example, four minutes, which is terminated at a moment of time t8 as depicted in Figure 4c, and opens the electronic switchgear 16 by means of the gate circuit T^ and thereby cuts off the battery voltage. If the dynamo voltage rises prior to the end of the delay time (for instance four minutes) t5-tl" as depicted in Figure 4a, the delay circuit 17 is made inactive by the first threshold-value switch 13 and the functions recommence as at the moment of time tl(tl').
The second threshold-value switch 15 (Figure 3) is activated at a moment of time t2 by means of the second voltage divider 14 (Figure 3), i.e. by the component voltage UT2 when the voltage Vx exceeds 4.8 V as shown in Figures 4a and 4d. When the voltage Vx falls short of 4.5 V at a moment of time t4 as seen by again referring to Figures 4a and 4d, the second threshold-value switch 15 is deactivated by the voltage Urj-^ and by means of the second voltage divider 14. During the activation period of the second threshold-value switch 15, the
energy-converter and energy-limiter device 10 (Figure 3) converts the output voltage Ua2 to a preferred level of 6.4 V. This occurs as soon as the traveling speed exceedsthe range of 5 to 7 kmph (Figures 4a and 4e). In the inactive range of the second threshold-value switch 15, i.e. when the traveling speed is lower than 3 kmph, the energy-converter and energy-limiter device 10 converts the output voltage Uai to 4.5 V up to 6 V, but preferably fixedly set to, for instance, 5.5 V as shown in Figure 4e.
The voltage-speed/time diagram depicted in Figure 4a and the four voltage/time diagrams depicted in Figures 4b to 4e are combined in a voltage/speed diagram illustrated in Figure 5a. The change-over from Ua = 4.5 V to Ua = 6.4 V occurs at a traveling speed of approximately 5 to 7 kmph.
The function/time diagrams illustrated in Figures 4a to 4e depict - dependent on and subject to the voltage + speed/ variatipn-in time (Figure 4a) - the function of the first threshold-value switch 13 (Figure 4b), the function of the delay circuit 17 (Figure 4c), the function of the second threshold-value switch 15 (Figure 4d) and the function of the output voltage Ua, i.e. Ua^ and Ua2 (Figure 4e) .
The delay circuit 17 is activated when the threshold voltage Vx falls short of approximately 0.8V. In other words, the bicycle comes to a stop. The delay circuit 17 now supplies by means of the gate circuit Tj_ and the switch Sj of the electronic switchgear 16 the voltage of the battery 4 during a period of four minutes to the circuit node 18 and thus to the energy-converter and energy-limiter device 10. The latter now produces the output voltage for standing light. At the end of
the time interval of four minutes, the switch S-L is opened and the entire system is thereby switched off. In case the first threshold-value switch 13 exceeds the control signal Vx, when during the delay interval the voltage Vx is equal to 0.8 V, the delay circuit 17 is set back to zero and there commences the normal traveling program as described hereinbefore under the title "First threshold-value switch 13".
In short, this means that when the bicycle comes to a stop, the standing or parking light will burn at least four minutes long. Upon starting anew, the lighting system changes over without interruption to the traveling program.
The battery monitoring circuit 19 depicted in Figure 3 monitors the charge condition of the accumulator battery 4 and the operational capability of the latter. In case the battery is discharged or defective, the battery monitoring circuit 19 will prevent the connection of the battery 4 to the circuit node 18, so that the system is run and operated according to Figure 5a directly by the dynamo generator 1 (voltage Ug), in such case without standing light, and by the energy-converter and energy-limiter device 10. It is thereby ensured that such accumulator batteries are protected against total discharge.
In Figures 5a, 5b and 5c there is illustrated the course of the output voltage Ua achieved by the bicycle lighting system constructed according to the present invention. The course or progression of such output voltage Ua is depicted in the form of a curve K^ extending between two areas defined by legal standards and shown in a hatched representation. The course of the output voltage is designated by the reference characters Ua^ and Ua2 as will be recognized in Figure 5b.
On the other hand, there is depicted in Figure 5a a curve K2 which shows the course of the output voltage of a conventional bicycle lighting system. The standing or parking light area is conveniently designated by reference character STL (standing light) and extends over a speed range from zero to approximately 5 kmph.
The aforedescribed bicycle lighting system constructed in accordance with the present invention brings many advantages, particularly the advantages listed hereinbelow:
The dynamo generator 1 disposes of a comparatively very high efficiency which produces a power output of more than 4.5 W at a traveling speed of approximately 5 to 7 kmph;
this dynamo power is converted to 6.4 V and kept constant at a speed above approximately 5 kmph by means of the upward and downward converting converter arrangement 5;
this energy is directly available, on the one hand, for charging the battery 4 and, on the other hand, for producing light;
the converter arrangement 5 operates already from 2 V with an input voltage starting from 1.5 V and up to 80 V, whereby 80 V would correspond to a traveling speed of approximately 80 kmph;
the ratio of energy apportioning in traveling light and standing light is obtained in a ratio of 1-2:1, that is two units traveling light and one unit standing light, irrespective of the traveling speed. This apportioning ratio is currently still quite limited by the charging capacity of accumulator
batteries. The ratio can be substantially reversed in the case of a heightened charging capacity and could be, for instance, a ratio of 0.5:1. However, such batteries are still not available or have other drawbacks;
the bicycle lighting system of the present invention meets by far all legal requirements, standards and specifications with respect to the dynamo-travel power curve, because constant and adequate energy for lighting and battery charging is non-intermittently available;
by virtue of the effected apportioning of the output voltage of the energy-converter and energy-limiter device 10 of the converter arrangement 5 to provide an output voltage of 4.5 up to 6 V at a speed below approximately 5 kmph and a "travel" voltage of 6.4 V, the Standard exacting 3 W for "standstill and travel" is perfectly fulfilled;
the battery-charging balance is very reliably ensured;
by virtue of the comparatively superior efficiency of the entire bicycle lighting system there is achieved a far lower riding resistance. In other words, the cycling or pedaling energy required to actuate and drive the dynamo system is substantially reduced in spite of increased dynamo power;
the application of the air-core coil 23 in the dynamo generator 1 eliminates magnetic ripple formation;
the dynamo'generator 1 has very low inductive losses, requires no sliding contacts and is, therefore, better and more reliable; and
the rotary motion of the entire magnetic circuit, i.e. the inner circuit 21 and the outer circuit 22, eliminates magnetic losses of the dynamo generator 1.
Figure 6 shows a preferred exemplary, accomplished embodiment of the converter arrangement 5 realized by means of a customized, solid-state, integrated switching circuit 50, at pins of which there are connected external circuit or control elements of the converter circuit.
Since all electronic functions are complex and costly and since the construction, which includes integrated standard switching circuits, would require a large number of components and component parts as well as a great deal of space, there are sensibly and efficiently realized all functions, digital and analog functions, together in a One-Chip-ASIC 50. A bicycle lighting system being a mass-produced or bulk article, it is evident that mass production of the customized, solid-state, integrated switching circuit 50 is also economically very worth-while. The components that cannot be integrated or cannot be sensibly integrated, such as the rectifier 11, the capacitors C^ to C$, a transformer, a power output transistor and further component parts, are connected to the pins of the customized, solid-state, integrated switching circuit 50 in the circuit arrangement illustrated in Figure 6.
By virtue of the provision of a customized solid-state integrated switching circuit 50 for the electronic functions of the converter arrangement 5, there is rendered possible a very compact and comparatively small converter arrangement 5, which together with the battery 4 can be accommodated in an adequately small housing or enclosure, which is either integrated with the dynamo housing or separately mountable thereat.
In Figure 7 there has been depicted a longitudinal section through an exemplary embodiment of the dynamo generator 1 constructed according to the present invention as a side dynamo including an integrated battery 4 and an integrated converter arrangement 5. The dynamo system is mounted in known manner at a swivel arm 34 and comprises an upper housing portion 30, which encompasses the rotating inner and outer circuits 21, 22 and the stationary coil sections 23.1 to 23.6, and a lower housing portion 31, which encompasses the battery 4 and the converter arrangement 5, this lower housing portion 31 being fixedly connected with the upper housing portion 30. The coil sections 23.1 to 23.6 are integrally formed with a housing base or bottom 37, and the converter arrangement 5 is connected by means of guide pins 39 with the coil sections 23.1 to 23.6. Connections or leads 33 to a front lamp 2 and a rear lamp 3 schematically shown in Figures 3 and 6 are located in the lower part of the lower housing portion 31. A sensor 32, designated by reference character 82 in Figures 3 and 6, is advantageously accommodated in the housing of the swivel arm 34. This sensor 32 detects that the complete dynamo system is not ready-for-operation in the idle or inoperative position thereof and supplies a signal to the converter arrangement 5, thus effecting immediate interruption of the existing standing or parking light. In other words, the sensor serves to deener-gize the entire bicycle lighting system when the dynamo system at the swivel arm 34 is tilted away. A driving wheel 35 driven by the bicycle wheel is fixedly connected with a dynamo arbor or axle 38 which, in turn, is connected with the support core of the inner circuit. This dynamo arbor or axle 38 is freely rotatably mounted in an upper pivot bearing 36 and a lower pivot bearing 36'. Although the dynamo system 1, 5 depicted in a longitudinal sectional view in Figure 7 is constructed as a laterally-mounted bicycle dynamo system, it will be readily
clear to those skilled in the art that the aforedescribed characteristics of the dynamo system 1, 5 constructed according to the present invention are also applicable for a roller dynamo system as shown in Figure 8 or for a hub dynamo system.
As also clearly evident by referring to Figure 6, there can be provided an alternative exemplary embodiment of the dynamo system 1, 5 in that the converter arrangement 5, the external components or component parts thereof and the battery 4 are kept apart from the dynamo generator 1 and arranged separately on the bicycle.
While there are shown and described present preferred embodiments of the invention, it is to be understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims.
WE CLAIM:
1. A generator comprising an inner circuit and an outer circuit, both of which are mounted to synchronously rotate in a same direction about a stationary stator and comprise, in each case, n poles in identical pole pitch, characterized in that said stator is a stationary air-core coil arranged between said inner circuit and said outer circuit, that said inner circuit comprises n inner pole shoes and that magnets are arranged in such a manner that they bear, in each case, in homopolar configuration against both sides of each of the n inner pole shoes, and that said outer circuit comprises n outer pole shoes facing the n inner pole shoes and projecting nose-shapedly to the latter, so that an air gap formed in each case between conjugate inner and outer pole shoes is the shortest path for the magnetic flux.
2. The generator as claimed in claim 1, wherein the n inner pole shoes
each comprise in a mid-portion thereof a slot forming an air gap
extending in radial direction in order to reduce the mutual
interference of the two magnets laterally resting in each case against
an inner pole shoe.
3. The generator as claimed in claim 1, wherein the sum of the adjacent
surfaces of the two lateral magnets bearing in each case against an
inner pole shoe is larger than a peripheral surface of each inner pole
shoe.
4. The generator as claimed in claim 1, wherein the air-core coil is
divided per pole field into two identical coil sections which are. pole-
correctly connected in series.
5. The generator as claimed in claim 1, wherein the number of poles n is
at least four, but preferably six.
6. A generator substantially as herein described with reference to and as
illustrated in the accompanying drawings.
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