JPH0453158Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a voltage stabilizing device for protecting a light bulb from excessive voltage of a bicycle generator whose voltage fluctuates.

(Prior art and its problems) In general, a bicycle headlamp uses an alternating current generator using a permanent magnet to generate light from a light bulb, but the output voltage of the generator fluctuates depending on the speed of the bicycle. The luminous intensity also varies greatly depending on the weather. Particularly when riding at high speeds, the light intensity becomes higher than necessary, causing the light bulb to break out more quickly, and the load increases accordingly, requiring great effort to pedal the bicycle.

In order to solve this problem, it has been proposed to provide a voltage stabilizer between the generator and the bulb so that the bulb does not receive a voltage higher than the rated voltage. As such a voltage stabilizing device, for example,
A relay is connected in parallel to the generator and a diode bridge is inserted between the generator and the light bulb.When the voltage is low, the AC power from the generator is full-wave rectified and supplied to the light bulb.When the voltage is high, There is one in which the diode connection is switched to half-wave rectification by the operation of a relay, so that approximately half the power is supplied to the light bulb. However, according to this, there is a problem that the power supplied to the light bulb is halved due to the operation of the relay, so there is no sufficient stabilization, and the bicycle suddenly becomes dark when it reaches a certain speed. .

In addition, negative feedback amplification systems and chopper systems that use transistors are also considered, but in these cases, the transistor is connected in series with the light bulb, which creates an internal resistance that causes the bicycle to run at extremely high speeds. There is a problem that the light bulb does not light up at all when the vehicle is moving (for example, when the vehicle is being pushed by hand), and it does not light up unless the speed reaches a certain level. Furthermore, since resistance heat generation of the transistor occurs, this results in power loss, resulting in poor efficiency, and there are also problems in that the circuit is complicated and expensive.

(Means for solving the problem) In view of the above-mentioned problem, the present invention is capable of sufficiently stabilizing the voltage and lighting the light bulb according to the speed of the bicycle even when the bicycle is traveling at an extremely low speed. The aim is to provide a possible voltage stabilization device, the technical means for which is to connect the coil of the relay in parallel with the light bulb, and to connect the contacts of the relay to the generator when the relay operates. A series connection body of a Zener diode and a capacitor, which are connected in a separated manner and have a Zener voltage higher than the operating voltage of the relay, is connected in parallel with the coil of the relay.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

In FIG. 1, a voltage stabilizing device 1 has a series connection body of a Zener diode Z0 and a coil 2a of a relay 2 connected in parallel with a light bulb L, which is a load, and a DC generator G between them. The normally closed contacts 2b of the relay 2 are connected in series. Therefore, the Zener voltage EZ0 of the Zener diode Z0 is applied to the coil 2a from the output voltage Eg of the generator G.
The voltage obtained by subtracting this will be applied. The Zener voltage EZ0 of the Zener diode Z0 is the sum of this and the operating voltage Er of the relay 2 (EZ0+Er=
Ea) is set to be slightly lower than the rated voltage Ec of the light bulb L. In parallel with the coil 2a of the relay 2, a series connection of a resistor R1, a Zener diode Z1 and a capacitor C1, and a resistor R
2. A series connection body of Zener diodes Z2 and C2 is connected.

Zener voltages of Zener diodes Z1 and Z2, respectively The above-mentioned relay operating voltages of EZ1 and EZ2
Er is selected to have the following relationship: Er<EZ1<EZ2 (1). Capacitors C1 and C2 have their respective Zener voltages
It is charged by a current when a voltage higher than EZ1 and EZ2 is applied to the coil 2a, and is discharged when the voltage across the coil 2a decreases, and the resistors R1 and R2 are protective resistors at that time.

The operation of the voltage stabilizing device 1 configured as described above will be explained with reference to FIGS. 2 and 3.
Figure 2 is a diagram showing the relationship between the speed of the bicycle, therefore the rotational speed of the generator G, its output voltage Eg, and the effective value Ee of the voltage applied to the light bulb.
The figure shows an example of the waveform of the voltage applied to the light bulb at points a, b, and c in FIG. 2. In FIG. 2, the output voltage Eg of the generator G increases with the speed of the bicycle and eventually reaches a saturated state. When the voltage applied to the coil 2a due to the rise in the output voltage Eg reaches the operating voltage Er of the relay 2, the relay 2 operates and the normally closed contact 2b opens, thereby reducing the voltage across the coil 2a. Since it becomes zero, relay 2 returns and operates again.
Becomes in a vibrating state. At this time, the voltage applied to the light bulb L has a pulse-like waveform with an on time T1 and an off time T2 as shown in Fig. 3a, and as a result, its effective value Ee is slightly reduced as shown in Fig. 2. This will result in a decline.

Thereafter, as the output voltage Eg rises, the voltage Ee also rises. When the voltage applied to the coil 2a reaches the Zener voltage EZ1 of the Zener diode Z1, the capacitor C1 is charged while the relay 2 is returning (during time T3 in FIG. 3b), and the relay 2 operates and the output voltage of generator G
When Eg is no longer applied to the coil 2a, the charge in the capacitor C1 flows to the coil 2a through the Zener diode Z1 and the resistor R1 (Fig. 3b).
(during time T4). Therefore, the time T4 during which the relay 2 is operating becomes longer, and the generator G is connected to the light bulb L.
As the time during which the output voltage Eg is not applied becomes longer, the effective value Ee does not increase much.

When the output voltage Eg further increases and the voltage applied to the coil 2a reaches the Zener voltage EZ2 of the Zener diode Z2, the capacitor C2 acts in the same way as the capacitor C1 described above. For this reason, the operating time T6 of relay 2 becomes longer, and the effective value Ee becomes smaller than the light bulb L.
The voltage will be kept almost constant, the same as the rated voltage Ec.

According to the above embodiment, even if the output voltage Eg of the generator G increases with the speed of the bicycle and exceeds the rated voltage Ec of the light bulb L, the effective value Ee applied to the light bulb L remains a constant voltage that is almost the same as the rated voltage Ec. is maintained and stabilized. Therefore, the luminous intensity of the light bulb L is almost constant, the light bulb L is less likely to break and has a longer life, and since the load is constant, it does not require effort as in the past to pedal a bicycle. Also, when riding the bicycle at extremely low speeds, relay 2 does not operate,
Since the generator G and the light bulb L are connected only through the contact point 2b with almost zero resistance, the light bulb L lights up according to the speed of the bicycle.

In the above embodiment, in order to extend the life of the contact 2b of the relay 2, a material with a high melting point, such as an alloy of tungsten and copper or silver, may be used. Although a charging circuit including Zener diodes Z1 and Z2 and capacitors C1 and C2 is provided in two stages, it may be provided in three stages or more. Therefore, it is also possible to have only one stage. It is also possible to omit the resistors R1 and R2. The effective value Ee of the voltage applied to the light bulb L is the rated voltage
It may be set to another value different from Ec. In order to adjust this, it is sufficient to set the Zener voltage EZ0 of the Zener diode Z0 to an appropriate value,
In some cases, it is also possible to omit the Zener diode Z0. A DC generator was used as the generator G, but if this is an AC generator,
It may be rectified using a diode bridge or the like. At that time, the contacts of the relay 2 may be inserted into the diode bridge or between the diode bridge and the alternator to disconnect the generator.

(Effects of the invention) According to the invention, even if the voltage of the bicycle generator fluctuates greatly, the voltage can be sufficiently stabilized, and there is a relay contact between the power source (generator) and the light bulb. Since the internal resistance is only interposed, the internal resistance is low, and since it is a chopper type, there is almost no power loss due to resistance heat generation, and the efficiency is high. Therefore, even when the bicycle is running at high speed, the luminous intensity of the light bulb does not become higher than necessary, preventing the light bulb from breaking, extending its life, and eliminating the need for extra effort to pedal the bicycle. What's more, even when the bicycle is traveling at very low speed, the light bulbs will light up according to the speed of the bicycle.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and Fig. 1 is a circuit diagram of the voltage stabilizing device 1, and Fig. 2 shows the relationship between the speed of the bicycle, the output voltage Eg of the generator, and the effective value Ee of the voltage applied to the light bulb. Figure 3 a, b, c
2 are diagrams showing examples of waveforms of the voltages applied to the light bulb at points a, b, and c in FIG. 2, respectively. 1... Voltage stabilizer, 2... Relay, 2a...
... Coil, 2b... Contact, G... Generator, L...
Light bulb, Z0, Z1, Z2... Zener diode, C1, C2... Capacitor.

Claims (1)

[Scope of utility model registration request] A coil of a relay is connected in parallel with the light bulb, and the contacts of the relay are connected so as to disconnect the generator when the relay is activated, and a zener diode and a capacitor having a zener voltage higher than the operating voltage of the relay are connected. A voltage stabilizing device for a bicycle generator comprising a series connection body connected in parallel with a coil of the relay.