JPS6253057B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a movable body orbiting type flow sensor, and more particularly to a movable body orbiting type flow sensor suitable for detecting fuel flow rate for automobiles.

In general, so-called drive computers have been used that are mounted on automobiles and display the fuel consumption rate, cumulative fuel consumption, remaining amount, etc. while the automobile is running, either moment by moment or at any time. As shown in FIG. 1, such a system includes a fuel flow sensor 3 installed in a pipe between a fuel pump 1 and a carburetor 2 of an automobile, and a vehicle speed sensor 4 attached to a vehicle speedometer cable outlet. A drive computer 5 installed in front of the driver's seat processes these two signals, and a display section 6 displays necessary information. Therefore, in particular, the fuel flow sensor 3 is required to be small, lightweight, simple in structure, and highly reliable for on-vehicle use.

For this reason, as the fuel flow rate sensor 3, a sensor having a simple structure in which a movable body such as a ball revolves is generally used. This movable body orbiting flow rate sensor is equipped with a circular passageway that allows the ball to orbit together with fuel, an inflow passageway and an outflow passageway that supply and discharge fuel to and from this passageway, and detects the rotational speed of the ball. This is used to detect the flow rate.

The conventional typical movable body orbiting flow rate sensor is now
- Shown in Figure 5. The flow sensor shown in this figure is
It has an annular tube 8 for accommodating the ball 7, and the annular tube 8 is provided with an introduction tube 9 extending tangentially. The introduction tube 9 and the annular tube 8 are made of the same tube body, and both form a continuous flow path. Further, the annular tube 8 is provided with an outlet tube 10 which is oriented in the opposite direction on the same tangent as the inlet tube 9. The outlet pipe 10 is a collection pipe of a branch pipe 11 formed at a position where the introduction pipe 9 and the annular pipe 8 communicate with each other. The fluid is introduced from the inlet pipe 9,
The state shown in FIG. 5 results in a clockwise streamline.
In order to cause this fluid to flow out into the outlet pipe 10 via the branch pipe 11, the annular pipe 8 is provided with a communication hole 12 which opens into the branch pipe 11, and also opens into the collecting pipe part at the collecting part position of the branch pipe 11. A communication hole 13 is provided. In such a flow sensor, the inlet pipe 9
The fluid flowing in from the annular pipe 8 flows clockwise in the figure, is guided from the communication hole 12 to the branch pipe 11, and is further discharged from the branch pipe 11 through the communication hole 13 through the outlet pipe 10. At this time, since the ball 7 circulates together with the fluid in the annular tube 8, the flow rate can be detected by detecting the rotation speed of the ball 7. An example of this type of prior art is Japanese Patent Laid-Open No. 48-66871.

However, in the above-described flow rate sensor, when flowing from the annular pipe 8 to the branch pipe 11, the fluid must pass through the flow hole 12 formed in the wall surface of the annular pipe 8, which distorts the flow line of the fluid and prevents it from flowing smoothly. This will result in poor flow and pressure loss. Furthermore, since the opening of the introduction pipe 9 to the annular pipe 8 and the communication hole 12 are very close to each other, the fluid does not go around the annular pipe 8 and flows directly from the introduction pipe 9 to the communication hole 12. There is a problem that the sensitivity of the sensor decreases because there is a few percent of backflow flowing. Moreover, the structure of such a flow rate sensor is extremely complicated, and no consideration is given to the so-called productivity of parts manufacturing and assembly work. In addition, especially when applied to the drive computer system of an automobile shown in Fig. 1, it is necessary to consider the pulsating flow caused by the fuel pump 1 and the carburetor 2, so it is usually necessary to attach some kind of pulsating flow absorbing device. In the flow rate sensor, since the inlet pipe 9 and the outlet pipe 10 are arranged in opposite directions, it is difficult to integrate the flow rate sensor with a pulsating flow absorbing device.
In addition, it is unsuitable for miniaturization, weight reduction, and cost reduction, and has problems that impair mass productivity and reliability.

Furthermore, FIGS. 6 and 7 show flow rate sensors according to other conventional examples. This flow rate sensor accommodates a ball 15 in an annular passage 14, and allows the ball 15 to move around within the annular passage 14. Annular passage 14
The inlet passages 16 are located approximately 180 degrees symmetrically.
and an outflow passage 17 are open, and the angle _θ1 formed by the intersection of the axes of these passages 16 and 17 and the axis of the annular passage 14 is set to approximately 180 degrees.

However, in such a flow sensor, the outlet 1
Since the distance between the ball 8 and the inlet 19 is long (angle θ ₂ in FIG. 6), the flow velocity in this portion becomes extremely slow, causing the ball 15 to stagnate. As a result, detection becomes difficult in a low flow rate region, and in automobiles, there is a problem in that detection is difficult in an engine idling flow rate region.

The present invention has focused on the above-mentioned conventional problems, and an object of the present invention is to provide a movable body orbiting type flow sensor that has low pressure loss and can detect flow rate with high sensitivity.

In order to achieve the above object, the movable body orbiting type flow rate sensor according to the present invention has an inflow passage and an outflow passage arranged in an X-shape with an annular passage that accommodates a movable body such as a ball so as to be able to circulate therethrough. The structure is constructed by arranging these inflow and outflow passages in the tangential direction of the annular passage, thereby creating a smooth flow of fluid and preventing the flow velocity within the annular passage from fluctuating, resulting in low pressure. This is designed to reduce loss and increase sensitivity.

Embodiments of the present invention will be described in detail below with reference to the drawings.

8 to 11 show a movable body orbiting type flow rate sensor according to this embodiment. Such a flow sensor is integrated with a pulsation absorber. As shown in these figures, the flow rate sensor 20 is made up of a pair of oval-shaped disks 21 and 22 that are bonded and fixed to each other, and each flow path is formed symmetrically between the surfaces of both the disks 21 and 22. I have to.

One end side of disks 21 and 22 (left end side in the figure)
, there is a cylindrical body part 2 erected outward from the disk surface.
3 and 24 are provided, and a chamber is defined by both cylindrical body parts 23 and 24. This chamber is diaphragm 2
5, the first chamber 26, the second chamber 26,
It is said to be Chamber 27. The diaphragm 25 is an oil-resistant rubber molded product with excellent flexibility. The first and second chambers 26 and 27 are provided with a fluid introduction pipe 28 and a fluid exit pipe 29, respectively.
into the chamber 26, while the second chamber 2
This allows the fluid inside 7 to flow out.

Further, an annular passage 30 is formed at the other end of the disks 21 and 22 (right end in the figure), and a ball 31 as a movable body is housed inside the annular passage 30. The ball 31 has a specific gravity similar to that of the fluid to be detected, and is made of, for example, a foamed resin material and molded into a spherical shape. Further, the annular passage 30 has a circular cross section with an inner diameter slightly larger than the outer diameter of the ball 31, so that the ball 31 can orbit within the passage 30.

Chambers 26, 27 and annular passage 30 at both ends
An inflow passage 32 for introducing fluid from the first chamber 26 into the annular passage 30 and an outflow passage 33 for leading out the fluid from the annular passage 30 are provided in the central portions of the disks 21 and 22 in which the annular passage 30 is formed. Both passages 32 and 33 intersect with each other in an X-shape within the plane in which the annular passage 30 is formed, that is, within the joint surface of the disks 21 and 22, and open into the annular passage 30. Further, the inflow passage 32 is connected to the first chamber 2
Similarly, the outflow passage 33 also communicates with the second chamber 27 through the inflow diagonal hole 34 so as to open only to the second chamber 27.
It is communicated with through the oblique outflow hole 35. The inflow passage 32 and the outflow passage 33 are arranged so that their axes are tangential to the axis of the annular passage 30.

Separation means is provided at the intersection of the inflow and outflow passages 32 and 33 formed to intersect in this way so that the fluids do not mix. This separation means is constructed by fitting a small-diameter circular tube nozzle 36 into the inflow passage 32 and forming a deep groove 37 with a streamlined cross section in the outflow passage 33 through which fluid can flow around the outer periphery of the nozzle 36. has been done. This nozzle 36
is a relatively long brass tube with a flange at one end,
It is securely installed in the inflow passage 32 by the flange. The nozzle 36 extends to an opening 38 of the inflow passage 32 to the annular passage 30 . The opening 38 of the inflow passage 32 is located close to the opening 39 of the outflow passage 33, and both openings 38 and 39 are connected to the island 4 formed as small as possible within the moldable range.
Separated by 0. The opening 39 of the outflow passage 33 with respect to the annular passage 30 has a rectangular cross-sectional shape, and the opening 39 of the outflow passage 33 with respect to the annular passage 30 has a rectangular cross-sectional shape.
1 is formed to be larger than at least the opening cross-sectional area of the inflow side opening 38 within a range that allows smooth circular movement without deviating from the annular passage 30.

Further, a detection means for detecting the rotation of the ball 31 is provided in the middle of the annular passage 30. This detection means includes an annular passage 3 as shown in FIG.
A pair of detection windows 41 facing the disk 2
1 and 22. This detection window 41 is molded from transparent resin or the like, and is arranged on the optical axis between a light emitter 42 provided on one disk 21 and a light receiver 43 provided on the other disk 22. There is. The light from the projector 42 is irradiated across the annular passage 30, and is blocked by the ball 31 passing therethrough. The light projector 42 and the light receiver 43 are each housed in a resin supporter 44, and are inserted and fixed into a light projecting case 45 and a light receiving case 46 provided on each disk 21, 22.

The operation of the flow rate sensor 20 according to this embodiment configured as described above is as follows. That is, introduction pipe 2
The fuel and other fluids flowing in through the first chamber 26 and the inflow oblique hole 3 as shown by the arrow in FIG.
4. The liquid flows into the annular passage 30 from the opening 38 via the inlet passage 32 and the nozzle 36. In the annular passage 30, the fluid forms a smooth circulating flow line, and part of the fluid flows out from the opening 39 after circulating, and the other part flows in the circumferential direction due to the flow velocity difference, that is, the pressure difference between the openings 38 and 39. Circulate. The fluid that has reached the opening 39 passes through the deep groove 37 provided on the outer periphery of the nozzle 36, as shown by the arrow in FIG.
The water then flows out through the outflow passage 32, the oblique outflow hole 35, the second chamber 27, and the outlet pipe 29. Due to the fluid flowing through such a flow path, the ball 31 in the annular passage 30 rotates within the passage 30 riding on the circulation of the fluid. Since the rotation speed of the ball 31 corresponds to the flow rate of the fluid, the flow rate can be detected by the detection means.

For this reason, according to this embodiment, the outflow passage 33 and its opening 39 are arranged in the forward direction of the circumference tangent at the outer edge of the annular passage 30, and the intersection with the nozzle 36 has a streamlined cross section. Since the deep groove portion 37 is provided, the outflow of fluid is extremely smooth, and therefore pressure loss is reduced. Also,
Openings 38 and 39 of inflow and outflow passages 32 and 33
Since these are located close to each other, there is no fluctuation in the flow velocity in these areas, and no stagnation of the balls 31 occurs. For this reason,
Sufficient sensitivity can be obtained even when the flow rate is low.

Furthermore, in this embodiment, since the first and second chambers 26 and 27 separated by the diaphragm 25 are communicated with the inflow passage 32 and the outflow passage 33,
The pulsation of the fluid is absorbed by the action of the diaphragm 25, and the rotation speed of the ball 31 accurately corresponds to the average flow rate.

Moreover, in terms of structure, the flow paths of the disks 21 and 22 are formed symmetrically, so die-casting,
It can be easily manufactured by molding, and mass production is possible.

Note that in the above embodiment, the inflow and outflow passages 32,
Although the cross-separation of 33 is performed by the nozzle 36, other dedicated separation pipes may be provided. Furthermore, although the cross sections of the ball 31 and the annular passage 30 are circular, they may have other shapes, as long as they are movable bodies that can circulate and move in response to the circular flow.

As described above, according to the present invention, a sensor with high sensitivity and low pressure loss can be obtained, and a highly reliable flow rate sensor can be obtained.

[Brief explanation of the drawing]

Figure 1 is a conceptual diagram of the drive computer, Figure 2
The figure is a plan view showing a conventional flow rate sensor, Fig. 3 is a side view of the same, Fig. 4 is a sectional view taken along the line - - of Fig.
The figure is a cross-sectional view taken along the - line in Fig. 3, Fig. 6 is a cross-sectional view of a flow rate sensor according to another conventional example, Fig. 7 is a cross-sectional view taken along the - line in Fig. 6, and Fig. 8 is a flow rate sensor according to the present embodiment. FIG. 9 is a sectional view taken along the line -- in FIG. 8, FIG. 10 is a sectional view taken along the same line, and FIG. 11 is a sectional view taken along the line XI--XI of the sensor. 20...Flow rate sensor, 30...Annular passage, 31
... Ball, 32 ... Inflow passage, 33 ... Outflow passage, 36 ... Nozzle, 37 ... Deep groove section.

Claims (1)

[Scope of Claims] 1. An annular passage and a fluid inflow/outflow passage communicating with the annular passage, a movable body housed in the annular passage that circulates together with the fluid, and rotation of the movable body detected. In a movable body orbiting type flow rate sensor that detects flow rate using a movable body, the inflow passage and the outflow passage are formed by intersecting each other in an X-shape via a separating means, and the two passages are respectively arranged in a tangential direction of the annular passage. A movable body orbiting flow rate sensor. 2. The movable body orbiting type according to claim 1, wherein the separation means comprises a nozzle disposed in the inflow passage and a deep groove of the outflow passage formed in the outer periphery of the nozzle. flow rate sensor.