JPH0452686Y2 - - Google Patents

Description

[Detailed Description of the Invention] a. Field of Industrial Application The present invention relates to a gas rate sensor, and particularly relates to a novel improvement for eliminating an unstable state of an output signal due to fluctuations due to compressional waves in a gas flow.

b. Prior Art A typical configuration of this type of gas rate sensor that has been used in the past is disclosed in Japanese Patent Application No. 124634/1989 filed by the present applicant and subsequently withdrawn. Among them, the configurations shown in FIGS. 5 to 8 can be mentioned.

In the figure, the casing designated by reference numeral 1 is approximately cylindrical as a whole and has both ends open. Each end of the casing 1 is connected to a pump holder 2 and a relay terminal plate 3. The inside of the casing 1 is closed off from the outside.

This pump holder 2 is provided with a diaphragm 4a made of an electrostrictive ceramic disk, and the peripheral edge of the diaphragm 4a is integrally fixed to the pump holder 2, so that the electrostrictive oscillating pump 4 (gas pump ) is formed.

Further, an electrode holder 5 is arranged inside the casing 1 at a position spaced apart from the diaphragm 4a by a predetermined distance, and the electrode holder 5 is constructed as shown in FIGS. 6 and 7. .

That is, four gas guide holes 5a to 5d are formed in the electrode holder 5, and four electrodes 6 are formed in the electrode holder 5.
a to 6d are arranged symmetrically with respect to the central axis. Among these electrodes 6a to 6d, electrodes 6a and 6b constitute a first electrode section 6A, and electrode 6c
and 6d constitute a second electrode portion 6B, and one temperature sensing element 7a made of a hot wire is provided on the first electrode portion 6A by welding, and the second electrode portion 6B is provided with a temperature sensing element 7a made of a hot wire. One temperature sensing element 7b is provided by welding.

Furthermore, a nozzle plate 10 having a nozzle hole 8 and an auxiliary hole 9 is provided in the vicinity of the relay terminal plate 3 in the casing 1, and between the relay terminal plate 3 and the nozzle plate 10, A dust plate 11 is provided at a substantially intermediate position.

A pump chamber 12 is formed between the diaphragm 4a of the electrostrictive vibration pump 4 (gas pump) and the pump holder 2, and the gas sent out by the electrostrictive vibration pump 4 is Guide holes 5a-5
It is sent to the gas flow path 13 via d.

A signal processing circuit section 14 consisting of an IC is provided at a position outside the relay terminal plate 3 of the casing 1,
This signal processing circuit section 14 receives power from the outside,
It is also connected to the relay terminal 15 of the relay terminal board 3 for taking out the output signals of the hot wires 7a and 7b to the outside.

Further, the relay terminal 3 is provided with a lead pin 16, and this lead pin 16 is connected to the outer casing 1.
It is connected to an external terminal 18 provided at 7.

The external terminal 18 is connected to the electric power required to operate the electrostrictive vibration pump 4 and the temperature sensing elements 7a and 7b.
The electric power required to heat the casing 1 is transmitted through the signal processing circuit section 14 and the lead pins 16, as well as through the plurality of lead wires 19 disposed in the axial direction inside the casing 1.
It has the function of supplying it appropriately through the. or,
This external terminal 18 has the function of outputting the output signal of each temperature sensing element 7a and 7b after passing through the signal processing circuit section 14 to the outside.

The conventional gas rate sensor is configured as described above, and its operation will be explained below.

First, when the electrostrictive vibration pump 4 (gas pump) is energized, the diaphragm 4a vibrates, compressing the gas in the pump chamber 12, and this compressed gas is transferred to the diaphragm 4a.
It flows into the flow path 13 through the discharge port 4b of the electrode holder 5 and the discharge port 5e of the electrode holder 5, is guided into the space formed between the nozzle plate 10 and the dust plate 11, and connects the nozzle hole 8 and the auxiliary port 9. Then, it is ejected through the space 1b in the casing 1 toward the temperature sensing elements 7a and 7b.

The aforementioned compressed gas uniformly cools each temperature sensing element 7a and 7b welded to each electrode 6a to 6d, and then is discharged toward the diaphragm 4a through the gas guide holes 5a to 5d. By the action of the electrostrictive vibration pump 4 (gas pump) again, the gas returns to the nozzle plate 10 via the flow path 13 and circulates within the casing 1 in the direction of the arrow.

In the above state, when no angular velocity is applied to the casing 1, each temperature sensing element 7a and 7b is cooled uniformly, but when an angular velocity is applied from the outside, the gas flow is deflected within the casing. death,
Non-uniform cooling occurs between each temperature sensing element 7a and 7b, and therefore each temperature sensing element 7a and 7
A slight voltage difference is generated between b and the angular velocity applied to the casing 1 can be detected by measuring this voltage difference.

c. Problems to be solved by the invention Since the conventional gas rate sensor was constructed as described above, it had the following various problems.

(1) The gas flow generated by the gas pump includes a sparse flow that has the vibration frequency of the gas pump, so the gas flow passing through each temperature sensing element has fluctuations due to the sparse flow. The output signal obtained from each temperature sensing element is
This resulted in an unstable state, which adversely affected the accuracy of the output signal.

(2) Therefore, when using a gas rate sensor to control the attitude and orientation of a rocket, weapon, etc. that requires extremely high precision, due to its characteristics,
Problems remained. Further, since each temperature sensing element was configured with one, it was impossible to switch the sensitivity as necessary.

The present invention was developed to solve the above-mentioned problems.In particular, it eliminates the unstable state of the output signal due to fluctuations due to compression waves in the gas flow, and also provides a gas sensor that allows sensitivity switching. The purpose is to provide a rate sensor.

d. Means for Solving the Problems The gas rate sensor according to the present invention includes a gas pump provided within a casing, an electrode holder provided adjacent to the gas pump, and an electrode holder provided opposite to the electrode holder. , a nozzle plate having a nozzle, a first electrode part and a second electrode part each having a pair of electrodes provided on the electrode holder;
and at least two temperature sensing elements provided in the second electrode part, each of the temperature sensing elements being parallel to each other, perpendicular to the direction of the gas flow, and provided on the streamline of the gas flow. be.

e Effect In the gas rate sensor according to the present invention, the temperature-sensing elements provided in each electrode part are configured as a pair in parallel and parallel to each other. The output signal is a very averaged value, and the influence of fluctuations as in the conventional method can be avoided.

Furthermore, when a pair of temperature sensing elements is provided with a switch means, temperature sensing switching can be performed by selectively connecting one of the temperature sensing elements.

f. Embodiments Hereinafter, preferred embodiments of the gas rate sensor according to the present invention will be described in detail with reference to the drawings.

Regarding the overall structure of the gas rate sensor,
Since it is exactly the same as the configuration explanation shown in Fig. 5,
To avoid redundant explanation, only the structure of the temperature sensing element of each electrode section and the signal processing circuit section, which is different from the conventional structure, will be explained with reference to FIGS. 1 to 4.

Further, the same or equivalent parts as in the conventional example will be described using the same reference numerals.

What is indicated by the reference numeral 5 in FIG. 1 is the main part of the electrode holder, and this electrode holder 5 has four gas guide holes 5a to 5d formed therein, and a gas guide hole consisting of a pair of electrodes 6a and 6b. A second electrode section 6B consisting of one electrode section 6A and a pair of electrodes 6c and 6d is formed.

Each of these electrode parts 6A and 6B has a pair of temperature sensing elements 7a and 7 formed in parallel to each other.
a' and 7b, 7b' are provided by welding.

The aforementioned temperature sensing elements 7a, 7a' and 7b, 7b' are
They are connected as shown in Fig. 3, and each temperature sensing element 7a
and 7a' are connected in parallel, and each temperature sensing element 7a'
b and 7b' are connected in parallel. Each of these temperature sensing elements 7a, 7a' and 7b, 7b' constitutes a bridge circuit 20 with reference resistors _R1 and _R2 , and an input section 21 of this bridge circuit 20 is connected to a constant current circuit as a power source. 22 is connected, and the output section 23 outputs a rate output signal for input to an amplifier (not shown).
A rate output terminal 24 that outputs R _put is connected.

The configuration shown in FIG. 4 shows another embodiment of the bridge circuit 20, in which a switch means 25 is connected to the input section 21, and a switching contact piece 25a is connected to each of the temperature sensing elements 7a, 7a' and It is configured to be able to be selectively switched to one end of each of 7b and 7b'.

The other configurations are the same as those in FIG. 3, so the same reference numerals are given and the explanation thereof will be omitted.

The gas rate sensor according to the present invention is constructed as described above, and its operation will be described below.

First, in the connection state shown in FIG. Exit 5
e, flows into the flow path 13, is guided into the space formed between the nozzle plate 10 and the dust plate 11,
Through the nozzle hole 8 and the auxiliary port 9, the temperature sensing elements 7a, 7a' and 7
b, 7b'.

To show in more detail the state of the gas flow in the space 1b mentioned above, the density of this gas flow is not constant, and as shown in FIG. and each of the temperature sensing elements 7
The distance D between a, 7a' and 7b, 7b' is set to about 1/2 of the wavelength of the compression wave. Note that the wavelength in this case is determined by the frequency of the electrostrictive vibration pump 4 and the physical constants of the gas flow.

Therefore, each temperature sensing element 7a, 7a' and 7b, 7
Since the sparse area a and the dense area b are repeatedly and continuously supplied to b', each of the temperature sensing elements 7a, 7a' and 7b, 7
b' are connected in parallel with each other as shown in FIG. , 7b' is dense, and as a result, it is possible to obtain a stable rate output signal R _put with almost no influence (fluctuation) of compressional waves.

Further, when each temperature sensing element 7a, 7a' and 7b, 7b' is configured as a switching type using a switch means 25 as shown in FIG. When switching to the temperature sensing element 7a, 7b side and when switching to the temperature sensing element 7a', 7b' side, the sensitivity is different in the state corresponding to the sparse area a and the dense area b, so that the switching means 25 is adjusted as appropriate.
can be used by switching. Therefore, rate output signals ( _Rput ) with different sensitivities can be obtained from the rate output terminal 24.

Note that although two temperature sensing elements are provided in each of the present embodiments, the same effect can be obtained even if three or more are used, for example.

g. Effects of the invention Since the gas rate sensor according to the invention is configured as described above, the following effects can be obtained.

(1) Since at least two temperature sensing elements are provided in each electrode part in a substantially parallel state, it is possible to eliminate the influence of fluctuations due to compressional waves and obtain a stable rate output signal.

(2) Furthermore, when each temperature sensing element is provided with a switch means, rate output signals with different sensitivities can be obtained without fluctuation.

[Brief explanation of drawings]

1 to 4 are for showing the gas rate sensor according to the present invention. FIG. 1 is a perspective view of the main parts, FIG. 2 is a state diagram showing the operating state of gas flow, and FIG. Figure 4 is a circuit diagram showing the wiring configuration; Figures 5 to 8 are for showing a conventional gas rate sensor; Figure 5 is a cross-sectional view; Figure 6 is a circuit diagram showing another wiring configuration; 7 is a front view of the main part, FIG. 7 is a perspective view of FIG. 6, and FIG. 8 is a circuit diagram. 1 is a casing, 4 is an electrostrictive vibration pump (gas pump), 5 is an electrode holder, 6a to 6d are electrodes, 6
A is the first electrode part, 6B is the second electrode part, 7a, 7
a', 7b, 7b' are temperature sensing elements, 8 is a nozzle hole, 10
25 is a nozzle plate, and 25 is a switch means.

Claims (1)

[Scope of claims for utility model registration] (1) Gas pump 4 provided in casing 1
an electrode holder 5 provided adjacent to the gas pump 4; a nozzle plate 10 provided opposite to the electrode holder 5 and having a nozzle hole 8;
A first electrode part 6 provided on the electrode holder 5 and each comprising a pair of electrodes 6a, 6b and 6c, 6d.
A and a second electrode part 6B, and at least two temperature sensing elements 7a, 7a' and 7b, 7b' provided in the first and second electrode parts 6A and 6B, respectively, each of the temperature sensing elements A gas rate sensor characterized in that 7a, 7a' and 7b, 7b' are substantially parallel to each other, perpendicular to the direction of the gas flow, and provided on the streamline of the gas flow. (2) The gas rate sensor according to claim 1, wherein the number of temperature sensing elements is at least three. (3) Each temperature sensing element 7a, 7a' and 7b, 7b' is
Claims 1 or 2 of the utility model registration claim characterized in that they are connected in parallel with each other.
Gas rate sensor described in section. (4) Each temperature sensing element 7a, 7a' and 7b, 7b' is
The gas according to any one of claims 1 to 3 of the claims for utility model registration, characterized in that the gas is configured such that the sensitivity can be switched by selectively switching to either one using the switch means 25. rate sensor.