JPH0614921U - Volume measuring device - Google Patents

Abstract

(57) [Summary] In order to prevent the liquefied fuel generated in the correction tank of the volume measuring device from accumulating on the speaker diaphragm, arrange the speaker diaphragm vertically. Another object is to provide a volume measuring device.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention changes the volume (volume) of the liquid contained in the tank by changing the volumes of the first and second microphones respectively provided in the main tank and the correction tank, and the main tank and the correction tank. The present invention relates to a volume measuring device for measuring using a volume changing means.

[0002]

[Prior art]

 A volume measuring device of this type has been applied, for example, in Japanese Patent Application No. 1-27808 (Japanese Patent Application Laid-Open No. 2-20723). In order to facilitate understanding of the present invention, the basic structure of the volume measuring device of the above application will be described with reference to FIG.

Reference numeral 1 is a speaker (volume changing means), and an oscillator 3 is connected to the volume changing means via an amplifier 2. The volume changing means partitions the main tank 4 and the correction tank 5. Further, a condenser microphone (first microphone) 6 is provided on the main tank 4 side, and a dynamic microphone (second microphone) 7 having lower sensitivity than the first microphone is provided on the correction tank 5 side. Has been. (Note that the second microphone may be configured to have a sensitivity equivalent to that of a dynamic microphone by attaching, for example, a tape having fine holes to the entire receiving surface of the condenser microphone.) The speaker 1 is driven at a predetermined angular frequency ω ₀ .

Here, the volume of the correction tank 5 is V ₂ , the volume of the gas in the main tank 4 is V ₁ , the volume of the liquid in the main tank 4 is V _L , and the volume of the gas in the main tank 4 is V ₁ . the sum of the volume V _L of the liquid in the main Ntanku 4 and V _T (total volume of the main tank 4).

The pressure change ΔP ₂ (t) in the correction tank 5 is

[0006]

[Equation 1]

[0007]

Further, the pressure change ΔP ₁ (t) in the main tank is

[0009]

[Equation 2]

[0010]

Assuming that the amplitude value of the pressure change in the correction tank 5 is A ₂ and the amplitude value of the pressure change in the main tank 4 is A ₁ , the ratio of these amplitude values is given by the equations (3a) and (3b).

[0012]

[Equation 3]

[0013]

From this

[0015]

[Equation 4]

Therefore, the volume V _L of the liquid stored in the main tank 4 is

[0017]

[Equation 5]

It becomes

It should be noted that ΔV is obtained in advance by experiments.

Next, a specific embodiment according to the present invention will be described based on the above principle.

A speaker (volume change means) 1 is placed between the correction tank 5 and the main tank 4. Further, in order to equalize the static pressures of the main tank 4 and the correction tank 5, both tanks 5, 4 are arranged. The main tank 4 and the correction tank 5 are connected to each other by a thin pipe 14 having an orifice 13 so that the main tank 4 and the correction tank 5 are substantially completely closed so as not to be affected by atmospheric pressure. Since the frequency ω ₀ is very large compared to the slow change of the atmospheric pressure and the fluid resistance in the ventilation hole 15 is very large, it seems that the ventilation hole 15 is blocked while the speaker 1 is driven. Since it operates, the atmospheric pressure inside the tanks 4 and 5 is not affected by the atmospheric pressure difference inside and outside the tanks 4 and 5. Here, the time constant of the pressure transmission of the pipe 14 is sufficiently larger than the time constant of the pressure change of the correction tank 5 by the speaker 1, and the time constant of the atmospheric pressure outside the tanks 4 and 5, that is, the pressure change time of the absolute pressure. If the speaker 1 is driven at an angular frequency ω ₀ , the pressure change ΔP ₂ (t) in the correction tank 5 is

[0022]

[Equation 6]

It becomes When the main tank (4) is rigid, the pressure change ΔP ₁ (t) is as follows.

[0024]

[Equation 7]

It becomes

[0026] That is, the speaker 1, the volume of each of the main tank 4 and the correction tank 5 v ₀ sinω ₀ t is regularly varied only the angular frequency omega _0, the correction tank 5 main tank 4 The respective pressure fluctuations of are detected by the condenser microphone 6 and the dynamic microphone 7 attached to the respective tanks 4 and 5, and the output of the condenser microphone 6 which has detected the pressure fluctuations of the main tank 4 is gain 1, center angular frequency. signal component of omega angular frequency omega ₀ by a band-pass filter 8 of ₀ is extracted, then fed to a second amplitude detector 9,

[0027]

[Equation 8]

Is detected and output. The output of the dynamic microphone 7 which has detected the pressure fluctuation in the correction tank 5 is extracted by multiplying the signal component of the angular frequency ω ₀ by V ₁ by the bandpass filter 10 having the gain V ₁ and the central angular frequency ω _0. Then, it is supplied to the first amplitude detector 11, and γP ₀ v ₀ is detected and output. After that, the output γP ₀ v ₀ from the first amplitude detector 11 is the output from the second amplitude detector 9.

[0029]

[Equation 9]

The gas volume V of the main tank 4 is divided by the divider 12 by₁ Is calculated, and the calculation result is supplied to the subtractor 24, and the total volume V of the set main tank 4 is calculated. _T Volume V of the liquid or the like stored in the main tank 4 as a result_L Is calculated.

[0031]

[Problems to be solved by the device]

 However, in the speaker 1 provided in the volume measuring device having the above configuration, since the diaphragm 1-1 of the speaker 1 is arranged in the horizontal direction, for example, this volume measuring device is used. When used as a fuel amount measuring device for a fuel tank for automobiles, if heating of the fuel in the tank by heating the engine or heating of the air temperature and subsequent cooling are repeated, for example, the correction tank 5 will be heated. The vaporized fuel is liquefied during cooling. That is, after the engine is started, the fuel in the fuel tank is delivered to the engine fuel injection device by the fuel pump, but the remainder of the fuel not consumed by the fuel injection device is heated by the heat near the engine. Return to the fuel tank. As a result, the fuel in the fuel tank is heated and the temperature rises.

On the other hand, the evaporated fuel vapor enters the correction tank through the orifices for adjusting the pressures of the main tank and the correction tank, but is liquefied by natural cooling after the engine is stopped. When this liquefied fuel (condensation) accumulates on the diaphragm 1-1 of the speaker and the amount of liquefied fuel that accumulates on the inside of the diaphragm 1-1 increases, the volume change operation of the speaker 1 due to the weight of the liquefied fuel. However, there is a problem in that the accuracy of volume measurement is deteriorated, and the adhesive strength of the adhesive connecting the voice coil of the speaker 1 and the diaphragm is deteriorated.

[0033]

[Means for Solving the Problems]

 The present invention has been made in view of such a conventional problem, and in order to prevent the liquefied fuel generated in the correction tank in the volume measuring device from accumulating on the diaphragm of the speaker, It is an object of the present invention to provide a volume measuring device which eliminates the above-mentioned problems by arranging the vibrating plate so that the surface of the vibrating plate is vertical.

[0034]

【Example】

 The present invention will be described in detail below with reference to the embodiment shown in FIG. 2. The same parts as those of the structure of the present embodiment and the structure of the conventional example are designated by the reference numerals used in the conventional example, and Description of the same structural parts is omitted.

That is, since the present invention has a feature in the speaker mounting structure, the structure of the speaker and the mounting structure will be described.

An annular yoke 31 is fixed to the speaker 30, and an annular magnet 33 is fixed to the peripheral edge of the yoke 31 by the yoke 31 and the plate 32. Further, the yoke 31 and the plate 32 that sandwich the magnet 33 are integrally fixed and held by an annular frame 34. Reference numeral 35 denotes a diaphragm which is sandwiched by a fixed ring 36 around the periphery of the annular frame 34. A bobbin 38 around which a voice coil 37 is wound and held is fixed to the center of the diaphragm 35. The bobbin 38 is loosely fitted in the annular through hole 39 provided in the yoke 31 so as to face the space portion 40 formed between the inner peripheral surface of the magnet 33 and the shaft portion of the yoke 31. It is located. Reference numeral 41 is an outlet provided in the yoke 31 for communicating with the space 40 and for discharging the condensed liquid (condensation) generated in the space 40 to the outside of the yoke.

The structure of the speaker 30 has been described above. Next, the mounting structure of the speaker 30 will be described. Reference numeral 42 denotes a correction tank wall for forming the correction tank 5 inside the main tank 4. An opening 43 is formed in the vertical wall of the correction tank wall 42. The opening 43 is closed by the diaphragm 35 of the speaker 30 so that the correction tank 5 has a speaker. 30 is fixed. A first microphone 6 and a second microphone 7 are attached to the outer side surface and the inner side surface of the correction tank wall 42, and the dew condensation inside the correction tank 5 occurs on the bottom wall surface of the correction tank wall 42. The pores 44 are provided to allow the liquid to be discharged into the main tank 4. Reference numeral 45 is a discharge port provided in the vibration plate 35 mounting portion of the annular frame 34.

The structure of the present embodiment is as described above. Next, the operation thereof will be described. The speaker 30 and the diaphragm 35 having the above structure are formed on the vertical wall of the correction tank wall 42 for forming the correction tank 5. Since the opening 43 is provided so as to be closed, the diaphragm 35 of the speaker is positioned in the vertical direction. Therefore, the condensed liquid does not collect on the diaphragm 35, the vibrating action of the diaphragm 35 is not impaired, and accurate speaker operation can be expected.

The liquid that has condensed in the space 40 of the speaker 30 is discharged to the outside of the speaker through the discharge port 41 and the discharge port 45 provided elsewhere, so that even on the inner surface of the diaphragm 35, condensation may occur. There is no harmful effect of the diaphragm 35.

As described above, in this embodiment, since the vibration plate 35 of the speaker 30 fixed in the correction tank 5 is arranged so as to be vertically positioned, dew condensation occurs in the tank. The liquid does not collect on the vibration plate 35, which effectively and accurately vibrates the speaker due to the pressure difference between the correction tank and the main tank, and a volume measuring device having excellent reliability and durability can be obtained. .

[0041]

[Effect of device]

 As described above, according to the present invention, the volume which is interposed between the main tank 4 and the correction tank 5 having a volume smaller than that of the main tank and which allows the respective volumes of the main tank and the correction tank to vary at a predetermined frequency A changing means 1, a first microphone 6 for detecting a pressure fluctuation in the main tank, a second microphone 7 for detecting a pressure fluctuation in the correction tank, and an amplitude of a detection signal of the first microphone. A first amplitude detecting circuit 9 for detecting a value, a second amplitude detecting circuit 11 for detecting an amplitude value of a detection signal of the second microphone, and an output of the second amplitude detecting circuit for the first amplitude detecting circuit. And a divider 12 that divides by the output of the amplitude detection circuit, and measures the volume of the object to be measured stored in the main tank based on the output of the divider. Since the volume measuring device uses the speaker 30 and is arranged such that the diaphragm 35 of the speaker is positioned in the vertical direction, according to this, the liquid condensed in the tank is not 35, the pressure changes in the compensation tank and the main tank due to the vibration of the speaker are effective and accurate, and the volume measuring device with excellent reliability and durability can be obtained. is there.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of the overall structure of a conventional volume measuring device.

FIG. 2 is an explanatory view of a main part structure of a volume measuring apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 30 ... Speaker 31 ... Yoke 32 ... Plate 33 ... Magnet 34 ... Frame 35 ... Diaphragm 36 ... Fixing Ring 37 ... Voice Coil 38 ... Bobbin 39 ... Annular Through Hole 40 ... Space 41 ... Discharge Port 42 ... Correction Tank Wall 43 ... Opening 44 ... Pore 45 ... Discharge port

Claims (1)

[Scope of utility model registration request] 1. A main tank (4) is interposed between a main tank and a correction tank (5) having a volume smaller than that of the main tank, and the respective volumes of the main tank and the correction tank are varied at a predetermined frequency. A volume changing means (1), a first microphone (6) for detecting a pressure fluctuation in the main tank, a second microphone (7) for detecting a pressure fluctuation in the correction tank, and the first microphone (6). First amplitude detection circuit (9) for detecting the amplitude value of the detection signal of the microphone
A second amplitude detection circuit (11) for detecting the amplitude value of the detection signal of the second microphone; and a division of the output of the second amplitude detection circuit by the output of the first amplitude detection circuit. In a volume measuring device comprising a calculator (12) and measuring the volume of the object to be measured stored in the main tank based on the output of the divider, a speaker (30) is used as a volume changing means, The volume measuring device is characterized in that the diaphragm (35) of the speaker is arranged in the vertical direction.