JP2000002574A - Flow rate measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust characteristics of an output signal to the actual flow rate by changing the mounting angle of an element support to a pipe. SOLUTION: An elongated arcuate mounting hole 8B with center at the axial line B extending in the radial direction of a pipe 1 is formed into a mount 8 of an element support 6 supporting a flow detecting element for detecting the flow rate of an intake air, and the element support 6 has a mounting angle to the flow line of the intake air (axial center O-O of the pipe 1) and hence the aperture area of a bypass passage is changed to change the flow speed of the intake air, thereby adjusting the characteristics of an output signal to the actual flow rate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow rate measuring device suitable for detecting an intake air flow rate of, for example, an automobile engine.

[0002]

2. Description of the Related Art In general, in an automobile engine or the like, a mixture of fuel and intake air is burned in a combustion chamber of an engine body, and the rotational output of the engine is obtained from the combustion pressure. It is required to detect the intake air flow rate in order to calculate the above.

Therefore, as a prior art of this type, for example, a flow rate measuring device disclosed in Japanese Patent Application Laid-Open No. 9-329472 is known.

Here, the flow rate measuring device comprises a pipe having a flow path through which a fluid to be measured flows, an element support having a base end attached to the pipe and a tip end projecting into the flow path, A flow rate detection element that is provided on the tip side of the element support and that detects the flow rate of the fluid to be measured by contacting the fluid to be measured in the flow path.

The flow rate detecting element according to the prior art comprises a ceramic substrate, a heater formed on the surface of the ceramic substrate and located at the center, and two resistance temperature detectors located on the left and right sides of the heater. Have been. And
When the fluid to be measured flows over the surface of the flow rate detecting element, the flow rate is detected by utilizing the change in the resistance value of each temperature measuring resistor cooled by the flow.

A circuit board is provided in the element support, and the circuit board is provided with a mounted electronic component, a heater control circuit for controlling a heater of the flow rate detecting element, and amplifies a detection signal of each temperature measuring resistor. , An amplification circuit, a flow adjustment circuit, a backflow detection circuit, and the like.

Further, in the flow rate measuring apparatus according to the prior art, in order to provide a bypass passage in the pipe, a passage forming body having a bypass passage is provided in the pipe, and the flow rate detecting element is arranged in the middle of the bypass passage by an element support. It is configured to be installed. Thus, even when pulsation occurs in the pipe, the device can accurately detect the flow rate of the measured fluid by bringing the measured fluid flowing in the bypass passage into contact with the flow detection element in a rectified state. Can be.

[0008]

In the above-mentioned prior art, the output signal with respect to the actual flow rate of the fluid to be measured is set by arbitrarily setting the amplification factor and the like of the flow rate adjustment circuit or the amplification circuit mounted on the circuit board. The output characteristics are adjusted.

However, since the output characteristics of the output signal may vary from product to product, it is difficult to absorb the variation from product to product. In addition, there is a problem that the output signal cannot be adjusted with respect to the actual flow rate, and the product yield is poor.

The present invention has been made in view of the above-mentioned problems of the prior art, and the present invention can perform the output characteristic of the output signal with respect to the flow rate of the fluid to be measured by adjusting the mounting angle of the element support. It is intended to provide a flow measuring device.

[0011]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, there is provided a pipe having a flow path through which a fluid to be measured flows, a pipe having a base end attached to the pipe and a tip end provided with the pipe. An element support that protrudes into the flow path, and a flow rate detection element that is provided on the distal end side of the element support and contacts a fluid to be measured in the flow path to detect a flow rate of the fluid to be measured. The flow angle measuring device comprises: between the base end side of the element support and the pipe, variably adjust the mounting angle of the element support with respect to the flow direction of the fluid to be measured in the flow path. It is characterized in that mounting angle adjusting means is provided.

[0012] With this configuration, the mounting angle adjusting means sets, for example, the mounting angle of the element support to be substantially parallel to the flow direction of the fluid to be measured, and to the angle with respect to the flow direction of the fluid to be measured. In this case, the flow rate of the fluid to be measured can be changed, and the characteristics of the output signal output from the flow rate detection element can be adjusted.

According to the second aspect of the present invention, a part of the fluid to be measured flowing in the flow path is provided on the tip end side of the element support member, and a bypass passage is provided in the middle position of the flow rate detecting element.
The mounting angle adjusting means changes the mounting angle of the element support to change the opening area of the bypass passage for the fluid to be measured.

With this configuration, when the mounting angle of the element support is, for example, substantially parallel to the flow direction of the fluid to be measured, the opening area of the fluid to be measured flowing through the bypass passage is increased, Its flow rate can be reduced. On the other hand, when the mounting angle of the element support is set to be an angle with respect to the flow direction of the fluid to be measured, the opening area of the fluid to be measured flowing through the bypass passage can be reduced, and the flow velocity can be increased.

According to the third aspect of the present invention, the mounting angle adjusting means includes:
The present invention is configured to change the mounting angle of the element support with respect to the tube by rotating the element support about an axis extending in the radial direction of the tube as a rotation center.

With this configuration, the element support is rotated about the axis extending in the radial direction of the tube as the center of rotation, and, for example, the mounting angle of the element support is substantially changed in the flow direction of the fluid to be measured. When parallel, the flow rate of the fluid to be measured can be reduced, and when the mounting angle of the element support is set at an angle to the flow direction of the fluid to be measured, the flow rate of the fluid to be measured is increased. Can be.

According to the fourth aspect of the present invention, the flow rate detecting element is formed of a chip-like element formed on a ceramic substrate, and a metal element mounting portion to which the flow rate detecting element is mounted is provided at the tip side of the element support. The element mounting portion is plastically deformed to change the relative angle of the flow rate detection element with respect to the flow of the fluid to be measured.

With this configuration, when the element mounting portion is plastically deformed and the relative angle of the flow rate detecting element with respect to the flow of the fluid to be measured is substantially parallel to the flow direction of the fluid to be measured, for example, In the case where the flow velocity of the fluid to be measured flowing to the flow rate detecting element side is reduced and the relative angle of the flow rate detecting element is set to an angle with respect to the flow direction of the fluid to be measured, the measured fluid flowing to the flow rate detecting element side Flow rate can be increased.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a flow rate measuring device according to the present invention will be described below in detail with reference to FIGS.

First, a first embodiment will be described with reference to FIGS. 1 to 10 by taking as an example an intake air flow rate measuring device used for intake air as a fluid to be measured.

Reference numeral 1 denotes a tube constituting a main body of the intake air flow rate measuring device. The tube 1 is formed in a cylindrical shape from, for example, a resin material, a metal material, or the like. A pipe wall 3 serving as a flow path 2 through which intake air flows,
It is substantially constituted by a small-diameter cylindrical mounting port 4 which is located substantially at the center of the tube wall 3 and protrudes outward in the radial direction.

The mounting port 4 is formed radially outward from the pipe wall 3 of the pipe body 1, and threaded holes 4A, 4A are formed in the distal end face thereof as shown in FIG. Accordingly, when the element support 6 described later is attached to the attachment port 4,
The nut 5 is inserted into the mounting slot 8B of the element support 6 and screwed into each of the screw holes 4A.
Is fixed to the tube 1.

Here, the pipe 1 is connected in the middle of the intake pipe of the engine, and an air cleaner (not shown) is provided at one end thereof.
The other end is connected to an intake manifold communicating with the inside of the cylinder of the engine via a throttle valve (neither is shown) or the like. The air cleaned by the air cleaner flows in the tube 1 in the direction of arrow A.

Reference numeral 6 denotes an element support. The element support 6 is constituted by a casing 7, a mounting plate 16, and the like, which will be described later. Is disposed in the middle of the bypass passage 13.

Reference numeral 7 denotes a casing formed of, for example, a resin material in the shape of a stepped column and serving as a base for the element support 6. The casing 7 has a mounting portion formed on the base end side and serving as mounting angle adjusting means. 8, a substrate accommodating portion 9 extending from the mounting portion 8 toward the inside of the tubular body 1 and having a substantially rectangular box shape as a whole, and a portion of the peripheral wall of the substrate accommodating portion 9 located on the distal end side. A mounting plate fitting groove 10 formed by chipping;
Passage forming body 1 located on the distal end side of the substrate accommodating portion 9
1 and a connector portion 12 which is formed on the mounting portion 8 outside the tubular body 1 and exchanges signals with the outside.

Here, the mounting portion 8 serving as mounting angle adjusting means.
As shown in FIG. 5, a flange 8A and a pair of mounting long holes 8B formed in the flange 8A and formed in an arc shape centered on an axis BB extending in the radial direction of the tubular body 1 are provided. It consists of. When attaching the element support 6 to the tube 1, the element 5 is inserted into the attachment slot 4, and then the nut 5 is inserted into the attachment slot 8 </ b> B of the attachment portion 8. 4 is screwed into the screw hole 4A. On the other hand, the casing 7
By loosening the nut 5, the (element support 6) is rotated in the direction of arrow C about the axis BB extending in the radial direction of the tube 1 by the length of the arc of each mounting long hole 8 </ b> B. It has a possible configuration.

The passage forming body 11 is formed as a vertically long rectangular body integrally formed with the casing 7, and the passage forming body 11 is located near the axial center OO of the tube 1.

Reference numeral 13 denotes a bypass passage provided in the passage forming body 11. The bypass passage 13 is formed substantially in a U-shape in the passage forming body 11, as shown in FIG. On the front surface of the passage forming body 11, the axial center O-
The outlet 15 is open at the lower surface of the passage forming body 11.

Reference numeral 16 denotes an attachment plate formed of a plate-like body attached to the substrate accommodating portion 9 of the element support 6. The attaching plate 16 is formed of, for example, a metal plate and is formed at a position facing the substrate accommodating portion 9. A substrate mounting portion 17; and an element mounting portion 18 integrally formed on the distal end side of the substrate mounting portion 17 and fitted in the mounting plate fitting groove 10 to project the distal end side to the outside of the casing 7, An element accommodation hole 19 (see FIGS. 4 and 6) for accommodating the flow rate detection element 21 is formed in a central portion of the element mounting portion 18.

Reference numeral 20 denotes a circuit board provided on the board mounting portion 17 of the mounting plate 16.
Electronic components for transmitting and receiving electric signals are mounted between the electronic components. These electronic components include a heater control circuit for controlling the heater of the flow rate detecting element 21, a backflow detection circuit, and the like.

Numeral 21 denotes a plate-shaped flow rate detecting element accommodated in the element accommodating hole 19 of the element mounting portion 18. Z).

As shown in FIG. 4, the flow rate detecting element 21 is formed on a rectangular ceramic substrate 21A and on the front end side of the surface of the ceramic substrate 21A extending from the mounting plate fitting groove 10. And a detecting unit 21B.
The detecting section 21B is generally constituted by a heater located at the center and two temperature measuring resistors (both not shown) located on the left and right sides of the heater. Further, the flow rate detecting element 21 is configured such that the intake air indicates the surface of the flow rate detecting element 21 by an arrow A.
When the air flows along the direction, the flow rate of the intake air is detected as an output signal by utilizing the change in the resistance value of each of the temperature measuring resistors of the detection unit 21B cooled by the air flow.

Reference numeral 22 denotes a sealing material filled in the substrate accommodating portion 9 so as to cover the circuit board 20 from the front side, and reference numeral 23 denotes a lid for covering the substrate accommodating portion 9.

The flow rate measuring device according to the present embodiment has the above-described configuration, and the detection operation will be described next.

That is, by attaching the element support 6 to the mounting opening 4 of the tube 1, the bypass passage 13 and the flow rate detecting element 21 are disposed at the axial center OO of the tube 1.
When the intake air flows through the flow path 2 in the direction indicated by the arrow A, the intake air rectified by the bypass passage 13 comes into contact with the flow rate detecting element 21. Can be accurately detected.

Also, in the present embodiment, the element support 6 is extended along the axis BB extending in the radial direction of the tubular body by the arc-shaped mounting long holes 8B, 8B formed in the mounting portion 8 of the element support 6.
Is rotated in the direction of arrow C around the center.

Here, as shown in FIG. 7 and FIG.
When the element support 6 is rotated about −B as the center of rotation and the mounting angle of the element support 6 is arranged substantially parallel to the axial center OO of the tube 1, the inside of the bypass passage 13 The opening area between the bypass passage 13 and the flow rate detecting element 21 formed in the above can be made large S1. This allows
Reduce the flow velocity of the intake air flowing through the bypass passage 13;
An output signal with respect to the flow rate of the intake air flowing in the tube 1 can be reduced.

On the other hand, as shown in FIGS. 9 and 10, when the mounting angle of the element support 6 is inclined with respect to the axial center OO of the tube 1, the element support 6 is formed in the bypass passage 13. The opening area between the bypass passage 13 and the flow rate detecting element 21 can be reduced to S2. Thus, the flow rate of the intake air flowing in the bypass passage 13 can be increased, and the output signal corresponding to the flow rate of the intake air flowing in the pipe 1 can be increased.

Thus, in the first embodiment, the mounting elongated portions 8B, 8B of the arc shape are formed in the mounting portion 8 of the element support 6.
Is formed, and when the element support 6 is attached to the mounting opening 4 of the tube 1 using the nut 5, the element support 6 is rotated and adjusted about the axis BB in the direction of arrow C. And Thus, an output signal corresponding to the flow rate of the intake air flowing in the direction indicated by the arrow A in the pipe 1 is performed by adjusting the mounting angle of the element support 6 with respect to the flow direction of the intake air. Can be.

As a result, the flow rate measuring device according to the present embodiment can change the mounting angle of the element support 6 to the direction indicated by the arrow A of the intake air flowing through the flow path 2 even after the flow rate measuring device is commercialized. By inclining with respect to the flow in the direction, the characteristics of the output signal with respect to the actual flow rate can be easily adjusted, and even if the output characteristics vary from product to product, the product yield can be improved.

Next, a second embodiment will be described with reference to FIGS. In the present embodiment,
The same components as those in the above-described first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 31 denotes an element mounting portion made of a metal plate used in place of the element mounting portion 18;
An element accommodation hole 32 is formed on one surface of the first element 1, and the flow rate detection element 21 is accommodated in the element accommodation hole 32.

In the present embodiment, since the portion where the flow rate detecting element 21 is mounted is constituted by the plastically deformable element mounting portion 31, the element mounting portion 31 is connected to the axis BB extending in the radial direction of the tube. By arbitrarily bending as the center of bending, the relative angle of the flow rate detecting element 21 with respect to the flow of the intake air can be adjusted.

That is, as shown in FIG. 11, when the relative angle of the flow detecting element 21 is arranged substantially parallel to the flow of the intake air, the suction flowing to the flow detecting element 21 side in the bypass passage 13 is performed. The flow rate of the air can be reduced, and the output signal corresponding to the flow rate of the intake air flowing in the tube 1 can be reduced.

On the other hand, as shown in FIG.
1 is plastically deformed and bent to give the relative angle of the flow rate detecting element 21, the bypass passage 13
It is possible to increase the flow rate of the intake air flowing toward the flow rate detecting element 21 in the inside, and to increase the output signal with respect to the flow rate of the intake air flowing through the pipe 1.

As a result, similarly to the first embodiment, even after the flow rate measuring device is commercialized, the element mounting portion 31 can be used.
, The characteristics of the output signal with respect to the actual flow rate can be easily adjusted by arbitrarily setting the relative angle of the flow rate detection element 21 with respect to the intake air, and the output characteristics varied from product to product. Even in this case, the product yield can be improved.

In the embodiment, the bypass passage 13
Although the case where the passage forming body 11 in which the is formed is formed integrally with the casing 7 has been described, the present invention is not limited to this, and as in a modified example shown in FIG. And a passage forming body 11 'having a bypass passage 13' at a position facing the mounting opening 4, and a flow detecting element 2 is provided in the middle of the bypass passage 13 'formed in the passage forming body 11'.
1 may be applied.

Further, in the first embodiment, the mounting angle of the element support 6 is adjusted about the axis BB extending in the radial direction of the tube 1 as a center of rotation, and in the second embodiment, plastic deformation is possible. Although the relative angle of the flow rate detecting element 21 with respect to the flow of the intake air is adjusted by the simple element mounting portion 31, the present invention is not limited to this, and the adjustment of the mounting angle of the element supporting body 6 by the rotation of the element supporting body 6. Of course, both adjustment of the relative angle of the flow rate detecting element by plastic deformation of the element mounting portion 31 may be performed.

[0049]

As described above in detail, in the first aspect of the present invention, for example, the mounting angle of the element support is adjusted by the mounting angle adjusting means, so that it is substantially parallel to the flow direction of the fluid to be measured. The flow rate of the fluid to be measured can be changed between the case and the case where the flow direction of the fluid to be measured has an angle with respect to the flow direction of the fluid to be measured. The characteristics of the output signal with respect to the actual flow rate can be easily adjusted by inclining with respect to the flow of the fluid to be measured flowing through the, and even if the output characteristics vary from product to product, the product yield is improved. be able to.

According to the second aspect of the present invention, a part of the fluid to be measured flowing through the flow path is provided at the tip end side of the element support, and a bypass passage is provided at an intermediate position of the flow rate detecting element.
Because the mounting angle of the element support is changed by the mounting angle adjusting means, for example, the mounting angle of the element support,
If it is almost parallel to the flow direction of the fluid to be measured,
When the opening area of the fluid to be measured flowing through the bypass passage is widened to reduce the flow velocity, and when an angle is provided with respect to the flow direction of the fluid to be measured, the opening area of the fluid to be measured flowing through the bypass passage is reduced. , Its flow rate can be increased. This makes it possible to absorb variations in output characteristics for each product.

According to the third aspect of the present invention, the mounting angle adjusting means includes:
Since the element support is rotated about the axis extending in the radial direction of the tube as a rotation center, when the mounting angle of the element support is substantially parallel to the flow direction of the fluid to be measured, the measured When the flow velocity of the fluid can be reduced, and the mounting angle of the element support is set to an angle with respect to the flow direction of the fluid to be measured, the flow velocity of the fluid to be measured can be increased.

According to the invention of claim 4, the flow rate detecting element is formed as a chip-shaped element formed on a ceramic substrate.
Since a metal element mounting portion to which the flow detection element is mounted is provided on the tip side of the element support, and the element mounting portion is plastically deformed, the relative angle of the flow detection element with respect to the flow of the fluid to be measured is set. By changing, it is possible to absorb variations in output characteristics of each product.

[Brief description of the drawings]

FIG. 1 is a front view showing a flow measurement device according to a first embodiment.

FIG. 2 is a longitudinal sectional view of the flow rate measuring device viewed from the direction of arrows II-II in FIG.

FIG. 3 is a plan view of the tube in FIG. 1 as viewed from above.

FIG. 4 is a front view showing the element support in FIG. 2 with a lid partially cut away.

FIG. 5 is a plan view of the element support as viewed from above.

6 is a longitudinal sectional view as seen from the direction of arrows VI-VI in FIG. 4;

FIG. 7 is a plan view showing a state where an element support is attached to a tube.

FIG. 8 is an enlarged view of an essential part showing an a part in FIG. 1 in an enlarged manner.

FIG. 9 is a plan view showing a state in which the element support is attached at an attachment angle with respect to the tube.

FIG. 10 is an enlarged view of a main part when viewed from the same position as in FIG. 8 in a state where the element support is attached at an attachment angle with respect to the tubular body.

FIG. 11 is an enlarged view of a main part showing a state in which the relative angle of the flow rate detecting element according to the second embodiment is arranged substantially parallel to the flow of intake air.

FIG. 12 is an enlarged view of a main part showing a state in which the relative angle of the flow rate detecting element according to the second embodiment has an angle with respect to the flow of intake air.

FIG. 13 is a longitudinal sectional view showing a state where a flow measuring device according to a modification of the embodiment is attached to a pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tube 6 Element support 7 Casing 8 Attachment part (attachment angle adjustment means) 11, 11 'Passage forming body 13, 13' Bypass passage 16 Attachment plate 18 Element attachment part 19, 32 Element accommodating hole 21 Flow rate detection element 31 Element Mounting part

Claims (4)

[Claims] A pipe having a flow path through which a fluid to be measured flows;
An element support having a base end attached to the tube body and a distal end projecting into the flow path; and an element support provided on the distal end side of the element support and coming into contact with the fluid to be measured in the flow path. In a flow rate measuring device comprising a flow rate detecting element for detecting a flow rate of a fluid measurement, between the base end side of the element support and the pipe, a flow direction of a fluid to be measured in the flow path is provided. A flow rate measuring device comprising a mounting angle adjusting means for variably adjusting a mounting angle of the element support. 2. A bypass passage through which a part of a fluid to be measured flowing in the flow channel flows at a tip end side of the element support member, and a flow passage detecting element is provided at an intermediate position thereof, The flow rate measuring device according to claim 1, wherein the mounting angle adjusting means changes an opening area of the bypass passage for the fluid to be measured by changing a mounting angle of the element support. 3. A configuration in which the mounting angle adjusting means changes the mounting angle of the element support relative to the tube by rotating the element support about an axis extending in a radial direction of the tube as a rotation center. The flow rate measuring device according to claim 1 or 2, wherein: 4. The flow rate detecting element comprises a chip-shaped element formed on a ceramic substrate, and a metal element mounting portion to which the flow rate detecting element is mounted is provided on a tip side of the element support. 4. The flow measuring device according to claim 1, wherein a relative angle of the flow detecting element with respect to the flow of the fluid to be measured is changed by plastically deforming the mounting portion.