JP2580569Y2 - Volume measurement device - Google Patents

Description

[Detailed description of the invention]

[0001]

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

[0002]

2. Description of the Related Art An application of this type of volume measuring apparatus has been filed, for example, in Japanese Patent Application No. 1-28088 (Japanese Patent Application Laid-Open No. 2-206723). 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.

[0003] Reference numeral 1 denotes a speaker (volume changing means) to which an oscillator 3 is connected via an amplifier 2. The main tank 4 and the correction tank 5 are configured to be partitioned by the volume changing means. 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. I have.
(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.) 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 tank 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) of the main tank
Is

[0009]

(Equation 2)

## EQU1 ##

Here, 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)

## EQU1 ##

From this

[0015]

(Equation 4)

The volume _VL of the liquid stored in the main tank 4 is

[0017]

(Equation 5)

## EQU1 ##

It is assumed that ΔV is obtained in advance by an experiment.

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

A speaker (volume changing means) 1 is placed between the correction tank 5 and the main tank 4. To equalize the static pressure between the main tank 4 and the correction tank 5, the loudspeaker (volume changing means) is provided between the tanks 5 and 4. Is a thin pipe 1 having an orifice 13
It is connected by 4, so that the main tank 4 and the correction tank 5 is not affected by atmospheric pressure, since a substantially fully closed system, atmospheric pressure driving angular frequency omega ₀ of the speaker 1 is slowly And the fluid resistance in the air hole 15 is very large, so that the air hole 15 acts as if the speaker 1 is being driven. The pressure is not affected by the pressure difference between the tanks 4 and 5 at all. Here this pipe 1
The time constant of the pressure transmission of 4 is sufficiently larger than the time constant of the pressure change of the correction tank 5 by the speaker 1 and sufficiently smaller than the time constant of the atmospheric pressure outside the tanks 4 and 5, that is, the pressure change of the absolute pressure. Speaker 1
Is driven at the angular frequency ω ₀ , the pressure change ΔP ₂ (t) of the correction tank 5 becomes

[0022]

(Equation 6)

## EQU1 ## When the main tank (4) is a rigid body, the pressure change ΔP ₁ (t) is as follows.

[0024]

(Equation 7)

## EQU1 ##

That is, the respective volumes of the main tank 4 and the correction tank 5 are set to v ₀ sinω ₀ t by the speaker 1.
Only at the angular frequency ω ₀ , the pressure fluctuations in the main tank 4 and the correction tank 5 are detected by the condenser microphone 6 and the dynamic microphone 7 attached to the respective tanks 4, 5. The signal component of the angular frequency ω ₀ is extracted from the output of the condenser microphone 6 which has detected the pressure fluctuation of the main tank 4 by the band-pass filter 8 having the gain of 1 and the central angular frequency ω ₀ , and then the second amplitude detector 9 Supplied to

[0027]

(Equation 8)

Is detected and output. Correction tank 5
The output of the dynamic microphone 7 detected pressure fluctuations, the gain V ₁ times, the center angular frequency omega ₀ of the band-pass by the filter 10 only the signal component of the angular frequency omega ₀ is V ₁
It is then multiplied and extracted, and then supplied to the first amplitude detector 11, where γP ₀ v ₀ is detected and output. Then the first
The output γP ₀ v ₀ from the amplitude detector 11 is the output from the second amplitude detector 9.

[0029]

(Equation 9)

Is divided by the divider 12 to calculate the gas volume V ₁ of the main tank 4.
Is supplied to the subtractor 24 is subtracted from the total volume V _T of the main tank 4 set the volume V _L of the liquid or the like accommodated in the result main tank 4 is calculated.

[0031]

However, in the speaker 1 provided in the volume measuring device having the above-described structure, the diaphragm 1-1 of the speaker 1 is disposed so as to be horizontal. For example, when this volume measuring device is used as a fuel amount measuring device for an automobile fuel tank, for example, heating of the engine or heating of the fuel in the tank by heating the air temperature and the subsequent cooling are repeated, The fuel vaporized in the correction tank 5 during heating is liquefied during cooling. That is, after the engine is started, the fuel in the fuel tank is sent out by the fuel pump toward the engine fuel injection device, but the remainder of the fuel not consumed by the fuel injection device is heated by the heat near the engine and the fuel tank is heated. Come back to. 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 an orifice for adjusting the pressure of the main tank and the correction tank, but is liquefied by natural cooling after the engine is stopped. If the liquefied fuel (condensation) accumulates on the diaphragm 1-1 of the speaker, and the amount of liquefied fuel accumulated on the inside of the diaphragm 1-1 increases, the weight change of the liquefied fuel hinders the volume changing operation of the speaker 1. As a result, there has been a problem that the volume measurement accuracy is reduced, and that the adhesive strength of the adhesive bonding the voice coil of the speaker 1 and the diaphragm is deteriorated.

[0033]

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and liquefied fuel generated in a correction tank in a volume measuring device does not accumulate on a diaphragm of a speaker. In order to solve the above-mentioned problem, it is an object of the present invention to provide a volume measuring apparatus which solves the above-mentioned problem by disposing the diaphragm surface of the speaker in a vertical direction.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiment shown in FIG. 2. The same parts of the structure of the present embodiment and the structure described in the conventional example are denoted by the same reference numerals used in the conventional example. The description of the same structure is omitted.

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

The speaker 30 has an annular yoke 31,
By the yoke 31 and the plate 32, an annular magnet 33 is fixed to a peripheral portion of the yoke 31. Further, the yoke 31 and the plate 32 holding the magnet 33 are integrally fixed and held by an annular frame 34. Reference numeral 35 denotes a diaphragm sandwiched between the peripheral edge of the annular frame 34 by a fixing ring 36.
A bobbin 38 for winding and holding the voice coil 37 is fixed to the center of the bobbin 38. The bobbin 38 loosely fits into an annular through hole 39 provided in the yoke 31 and
3 is located so as to face a space 40 formed between the inner peripheral surface of the yoke 3 and the shaft of the yoke 31. Reference numeral 41 denotes a discharge port which is provided in the yoke 31 and communicates with the space 40, and discharges a condensate (condensation) generated in the space 40 to the outside of the yoke.

The above is the structure of the speaker 30. Next, the mounting structure of the speaker 30 will be described.
Is a correction tank wall for forming the correction tank 5 inside the main tank 4, and an opening 43 is formed in a vertical wall of the correction tank wall 42.
Is closed by the diaphragm 35 of the speaker 30 so that the speaker 30 is fixed in the correction tank 5. The first microphone 6 and the second microphone 7 are provided on the outer and inner surfaces of the correction tank wall 42, respectively.
Is mounted on the bottom wall of the correction tank wall 42, and the liquid condensed in the correction tank 5 is supplied to the main tank 4
A small hole 44 for discharging the gas into the inside is provided. Reference numeral 45 denotes a discharge port provided in the attachment portion of the vibration plate 35 of the annular frame 34.

The operation of the present embodiment has been described above. Next, the operation 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. The diaphragm 35 of the speaker is provided so as to close the opened opening 43.
Will be located vertically. Therefore, the diaphragm 35
Above, no dew condensation liquid accumulates, and the vibration action of the diaphragm 35 is not impaired, so that accurate speaker operation can be expected.

The liquid condensed in the space portion 40 of the speaker 30 is discharged to the outside of the speaker through the discharge port 41 and another discharge port 45 provided outside the speaker. There is no evil of 35.

As described above, in the present embodiment, since the diaphragm 35 of the speaker 30 fixed in the correction tank 5 is disposed so as to be positioned vertically, the liquid condensed in the tank is formed. Does not accumulate on the diaphragm 35, whereby the vibration action of the speaker due to the pressure difference between the correction tank and the main tank is effectively and accurately performed,
A volume measurement device having excellent reliability and durability can be obtained.

[0041]

As described above, according to the present invention, the main tank and the correction tank having a smaller volume than the main tank are interposed and the respective volumes of the main tank and the correction tank are adjusted to a predetermined frequency. Means for varying the pressure, a first microphone for detecting pressure fluctuations in the main tank, a second microphone for detecting pressure fluctuations in the correction tank, and an amplitude of a detection signal of the first microphone. A first amplitude detection circuit for detecting a value, a second amplitude detection circuit for detecting an amplitude value of a detection signal of the second microphone, and an output of the second amplitude detection circuit for the first amplitude detection. In a volume measuring device having a divider for dividing by an output of a circuit, a correction tank 42 is fixed in position inside the main tank 4, and inside the correction tank 42,
The speaker 30 as the volume changing means is connected to the speaker 3
The amplitude plate 35 is fixed so that the direction of the zero amplitude plate 35 is vertical, and an opening 43 is formed in an upright surface of the correction tank facing the vibration plate 35. Is a volume measurement device in which the inside of the tank is shielded by the vibration plate 35, so that liquid condensed in the tank does not accumulate on the vibration plate 35,
As a result, the pressure change in the correction tank and the main tank due to the vibration action of the speaker is effectively and accurately made, and an effect is obtained in that a volume measuring device excellent in reliability and durability can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view of the entire structure of a conventional volume measuring device.

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

[Explanation of symbols]

 REFERENCE SIGNS LIST 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 outlet 42 correction tank wall 43 Opening 44: Pores 45: Outlet

Claims (1)

(57) [Scope of request for utility model registration] 1. A volume changing means interposed between a main tank and a correction tank having a volume smaller than the volume of the main tank, wherein the volume changing means varies respective volumes of the main tank and the correction tank at a predetermined frequency. A first microphone that detects pressure fluctuations in the main tank, a second microphone that detects pressure fluctuations in the correction tank, and a first amplitude that detects an amplitude value of a detection signal of the first microphone A detection circuit, a second amplitude detection circuit for detecting an amplitude value of the detection signal of the second microphone, and a division for dividing an output of the second amplitude detection circuit by an output of the first amplitude detection circuit In a volume measuring device provided with a compensator, a correction tank (42) is fixed in position inside the main tank (4), and a speaker ( 30) is fixed so that the direction of the amplitude plate (35) of the speaker (30) is vertical, and an opening (43) is formed in the upright surface of the correction tank facing the diaphragm (35). ), And the opening (43) and the inside of the correction tank (42) are blocked by the diaphragm (35).