JPS6230827B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an atomizing device for an inhaler that atomizes a liquid using ultrasonic vibrations.

FIG. 1 shows a schematic configuration diagram of an inhaler spray device X, in which 1 is an ultrasonic vibrator that generates ultrasonic waves;
Reference numeral 2 denotes an ultrasonic vibration horn that mechanically resonates the vibrations produced by the ultrasonic vibrator 1 to atomize the liquid 8 in the container 7 through the water absorber 9. 6 is a driving power source. Then, the ultrasonic vibration horn 2 is ultrasonically vibrated by the vibration of the ultrasonic vibrator 1 in the drive power source 6,
Liquid 8 is sprayed from the tip of water absorbent body 9. If the ultrasonic vibration horn 2 is now driven when the liquid 8 to be sprayed is exhausted or the water absorber 9 that supplies the liquid 8 is removed, the amplitude will increase and the internal stress of the ultrasonic vibration horn 2 will increase. increase and lead to damage,
The ultrasonic vibration horn 2 must always have a constant vibration width so that the internal stress does not exceed the allowable stress of the material.

Furthermore, when spraying, the following steps are involved before the liquid is atomized. That is, when the ultrasonic vibrator 1 starts to vibrate, the tip of the ultrasonic vibration horn 2 vibrates in the direction of the arrow in the figure, as shown in FIG. 2a.
Next, a water film is formed on the spray surface at the tip of the ultrasonic vibrating horn 2, as shown in FIG. In such a case, there are the following problems. That is, in order to drive the ultrasonic vibration horn 2 with small electric power, it is driven at the mechanical resonance frequency of the ultrasonic vibration horn 2. Therefore, it takes a considerable amount of time to set the amplitude of the atomizing surface at the tip of the ultrasonic vibrating horn 2 to a value that allows constant atomization, and the liquid 8 to be atomized is vibrated by the atomizing surface of the ultrasonic vibrating horn 2. As soon as it starts, it spreads over the entire atomizing surface. Due to the water film at the tip of the ultrasonic vibrating horn 2, the input impedance of the ultrasonic vibrator 1 increases, and it is necessary to increase the voltage in order to provide the power necessary for spraying. On the other hand, after becoming a steady spray, the water film becomes extremely narrow and the liquid 8 is sprayed as soon as it is sucked up, so the input impedance of the ultrasonic transducer 1 decreases and the input power further increases, similar to the above. The internal stress of the ultrasonic vibration horn 2 increases, and there is a risk that the ultrasonic vibration horn 2 will be damaged. When making an inhaler that is convenient to carry using the ultrasonic vibrating horn 2 having such characteristics, it is necessary to supply electric power to the ultrasonic vibrating horn 2 according to the load state using a battery as a power source. At this time, since the power source is a battery, this drive is required to be as efficient as possible.

The present invention has been provided in view of the above-mentioned points, and an object of the present invention is to provide a spraying device in which the ultrasonic vibration horn is not damaged and has good power efficiency.

Embodiments of the present invention will be described in detail below with reference to the drawings. Fig. 3 shows a block circuit diagram, where E is a battery power source, 4 is a step-up constant current circuit mainly composed of a DC-DC converter, and 5 is a constant current output of the step-up constant current circuit 4 as a drive source. as ultrasonic transducer 1
This is an oscillation circuit that vibrates. Further, the boost constant current circuit 4 includes an oscillation control circuit 11 consisting of two transistors Q ₁ and Q ₂ , etc., a linking choke booster circuit 10 consisting of a choke coil L ₁ , a transistor Q ₃ , etc., a resistor R ₈ , a transistor Q ₄ , etc. It is composed of a feedback circuit 12 and the like. The oscillation control circuit 11 includes transistors Q ₁ , Q ₂ ,
DC consisting of resistors R ₁ , R ₂ , R ₃ , R ₄ and capacitor C ₁
- Composed of a DC converter, oscillation control circuit 11
Linking chain booster circuit 1 that boosts the output of
It is input to the base of transistor _Q3 of 0.
The voltage boosted by the choke coil _L1 is charged in a capacitor _C3 and is supplied as a driving source for the oscillation circuit 5, which is a load. Feedback circuit 1
2 detects the load current flowing through resistor R ₈ and connects it to resistor R ₉
The oscillation period of the oscillation control circuit ₁₁ is changed by the transistor _Q4 . R ₇ is a resistor and C ₂ is a capacitor. The oscillation circuit 5 is composed of a transistor Q ₅ , a transformer TR, a chiyoke coil L ₂ , a capacitor C ₅ and the like, forming a Hartley oscillation circuit, and uses the output of the step-up constant current circuit 4 as a power source to vibrate the ultrasonic transducer 1 . That is, the step-up constant current circuit 4 boosts the voltage of the battery power source E to the voltage necessary for spraying the ultrasonic vibrating horn 2, and further makes the input current of the oscillation circuit 5 a constant current, thereby supplying the voltage to the ultrasonic vibrator 1. This is to make the drive current of the ultrasonic transducer 1 almost constant, and to make the amplitude of the ultrasonic transducer 1 constant. The oscillation circuit 5 is for driving the electrostrictive ultrasonic transducer 1 near its mechanical resonance point. Figure 5 shows ultrasonic transducer 1
Fig. 6 shows the relationship between frequency, impedance, and phase, and fr in the figure shows the resonant frequency and fa shows the anti-resonant frequency. As shown in FIG. 6, the oscillation circuit 5 constitutes a Hartley oscillation circuit as described above by utilizing the inductance oscillation of the ultrasonic transducer 1 near the resonance point.

Now, in the specific circuit diagram shown in Fig. 4, when the switch SW is turned on, the poles of the battery power source E, the switch SW, the resistor R ₁ , the capacitor C ₁ , the resistor R ₃ , the resistor
A current flows through R ₄ , resistor R ₅ , resistor R ₆ and the poles of battery power source E to charge capacitor C ₁ . At this time, the value of resistor R ₃ is made larger than that of resistors R ₁ , R ₄ , R ₅ , and R ₆ so as not to exceed the base-emitter voltage V _BE of transistors Q ₂ and Q ₃ . Voltage is applied to resistors R ₄ and R ₆ . Now, when the voltage of the charged capacitor _C1 exceeds the base-emitter voltage of the transistor _Q1 , the transistor _Q1 turns on and collector current begins to flow. Here, if the feedback from the feedback circuit 12 is not applied and the transistor _Q4 is in the off state, the transistor
Q ₂ is immediately turned on and the output voltage is applied to the base of transistor Q ₃ . At this time, a voltage of _{R 1 /} R ₁ +R ₅ +R ₆ V is applied to the resistor R 1 and the transistor Q ₁ is completely turned on. Note that V is the voltage of the battery power source E. When the transistor Q ₁ is turned on, current flows to the pole of the battery power source E, the transistor Q ₁ , the resistor R ₂ , the capacitor C ₁ , the transistor Q ₂ , the resistor R ₅ , the transistor Q ₃ and the pole of the battery power source E. The voltage on capacitor _C1 drops. Here, when the sum of the voltages V _C1 and V _R1 applied to the resistor R ₁ and the capacitor C ₁ becomes smaller than the base-emitter voltage V _BE of the transistor Q ₁ , the transistor Q ₁ is turned off, and therefore the transistor Q ₂ is also turned off. Therefore, it returns to its original state. Therefore, the output voltage from the oscillation control circuit 11 is output across the resistor R ₆ to the transistor of the linking choke booster circuit 10 in the next stage.
The current is input to Q ₃ , transistor Q ₃ is turned on and off, and current flows through chiyoke coil L ₁ . And when transistor Q ₃ is off, the chiyoke coil L ₁
The back electromotive force causes diode D ₂ to conduct, charging capacitor C ₃ and boosting the voltage. A current is supplied to the next stage oscillation circuit 5 by the electric charge charged in the capacitor C ₃ in this way. When the current of the oscillation circuit 5 flows, it is changed into a voltage value by the current flowing through the resistor _R8 . Resistance at a certain voltage depends on this voltage value
Transistor _Q4 is turned on via _R9 . When transistor Q ₄ turns on, the base current flowing to transistor Q ₂ decreases, making it difficult for transistor Q ₂ to turn on. That is, the off period of the transistor _Q2 , that is, the off period of the oscillation output is extended, and the oscillation period changes. Also transistor Q ₃
When the input voltage increases, the on-time time of transistor Q ₃ decreases, so the collector current of transistor Q ₃ does not increase with input voltage, and the base drive of transistor _Q It also requires less. When the load current increases in this way, the oscillation frequency of the oscillation control circuit 11 is changed by the feedback circuit 12, and the off period of the transistor _Q3 of the linking choke booster circuit 10 is lengthened to maintain a constant current. Therefore, the efficiency is high and the battery life is long.

By the way, the equivalent electric circuit at the resonance point of the ultrasonic transducer 1 driven by the oscillation circuit 5 using the output of the boost constant current circuit 4 as a drive source is shown in FIG. The amplitude of the mechanical side of the ultrasonic vibrator 1 is proportional to the vibration speed because the resonance frequency hardly changes. Furthermore, if the load is light, the force coefficient A does not change much, so the vibration speed is approximately proportional to the input current on the primary side. Now, if the output current of the power supply is constant, the vibration speed v will remain constant even when the load ra increases, and the resonance frequency will also change.
Since it is about 0.2 to 0.5%, the amplitude can be kept constant. Since the oscillation output current of the oscillation circuit 5 and the DC input current are approximately proportional, making the input current of the oscillation circuit 5 a constant current keeps the amplitude constant. That is, since the output of the boost constant current circuit 4 is a constant current, the input current to the oscillation circuit 5 is a constant current, and as described above, the amplitude of the ultrasonic transducer 1 is kept constant. Become. Also, due to the vibration of the ultrasonic vibrator 1, the water absorbing body 9 is attached to the tip surface of the ultrasonic vibration horn 2.
When they come into contact and a water film is formed, the load resistance ra shown in Figure 7 increases. Since the vibration velocity v is now constant, the primary input voltage V is increased so that the excitation force F is increased, and the electric power input to the ultrasonic vibration horn 2 is increased to start spraying. As the amount of water supplied increases, the input power to the ultrasonic vibration horn 2 increases accordingly, making it possible to perform extremely stable spraying.

As described above, the present invention provides a step-up constant current circuit using a battery as a power source, and uses the boosted and constant-current output of the step-up constant current circuit by detecting a load current as a drive source for an oscillation circuit. Since the ultrasonic vibrator is driven by the output of the oscillation circuit, the amplitude of the mechanical side of the ultrasonic vibrator is proportional to the vibration speed, and this vibration speed is approximately proportional to the input current, so the oscillation circuit If the current flowing into the circuit is made constant by a step-up constant current circuit, the amplitude of the ultrasonic vibrator will also be constant, and unlike conventional methods, the ultrasonic vibrating horn will destroy the ultrasonic vibrator due to the amplitude increase due to load fluctuations. This has the effect of preventing Moreover, since the power source is a battery power source, the spray device of this embodiment can be used to provide a portable and convenient inhaler.

[Brief explanation of the drawing]

Figure 1 is a schematic configuration diagram of a conventional spraying device;
Figures a to c are explanatory diagrams showing the state leading to the same spraying as above,
FIG. 3 is a block circuit diagram of an embodiment of the present invention;
The figure is a specific circuit diagram of the same as above, Figure 5 is an equivalent circuit diagram near the resonance point of the same as above ultrasonic transducer, and Figures 6 a and b are characteristic diagrams showing the relationship between frequency, impedance and phase as above, respectively. Figure 7 is an equivalent circuit diagram at the resonance point of the above ultrasonic transducer, where 1 is the ultrasonic transducer;
2 is an ultrasonic vibration horn, 4 is a step-up constant current circuit, 5
is an oscillation circuit, and E is a battery power source.

Claims (1)

[Scope of Claims] 1. In a spraying device that vibrates an ultrasonic vibrator and uses the ultrasonic vibration to drive an ultrasonic vibration horn to spray a liquid, a step-up constant current circuit using a battery as a power source is provided, The boosted constant current output of the boosted constant current circuit and the output that has been made constant by detecting the load current is used as a drive source for an oscillation circuit, and the ultrasonic transducer is driven by the output of the oscillation circuit. spray device. 2 A switching type of boost constant current circuit is used as the step-up constant current circuit.
The spraying device according to claim 1, characterized in that a DC-DC converter is also used.