JP2000346631A - Hole diameter measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the diameter of each hole in a member having holes of different diameter by detecting the fluid pressure when the member is placed in a noncompressive fluid in a reservoir and the quantity of fluid is varied by varying the fluid pressure. SOLUTION: A tip nozzle 13 having holes 14a-14c of different diameter is placed in a reservoir 2 and mercury L in the reservoir 2 is pressurized gradually at a predetermined rate in a pressurizing unit 8. The mercury L does not flow into each hole when it is not pressurized and when the mercury pressure P detected by a pressure sensor 10 reaches a some level PcL, the mercury L flows into the hole to move a pressurizing rod 9 and a moving amount sensor 11 detects the quantity of mercury being varied. Average pressure Pc of the PcL and a slightly higher pressure PcH is set as a mercury inlet pressure and an electronic controller 12 calculates the diameter of the hole 14c from the mercury inlet pressure Pc based on a prestored relation map of the mercury pressure P and the hole diameter. Furthermore, the mercury pressure P is increased and variation in the quantity of mercury is detected at a pressure Pb higher than the inlet pressure Pc and at a pressure Pa higher than the Pb. Diameters of the holes 14b, 14a are calculated based on the pressures Pb, Pa, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hole diameter measuring device.

[0002]

2. Description of the Related Art For example, an apparatus for measuring the diameter of an injection hole of a fuel injection valve of an internal combustion engine is disclosed in Japanese Utility Model Laid-Open Publication No. 63-150078.
No. 6,009,045. Here, the compressed gas is sent to the injection hole, and the diameter of the injection hole is measured based on the amount of gas flowing through the injection hole.

[0003]

In the hole diameter measuring device disclosed in the above publication, when the members have holes having different diameters, the diameters of these holes cannot be measured. The reason is that the above hole diameter measuring device measures the diameter of the hole based on the amount of gas passing through the hole, so if the member has holes with different hole diameters, only the total gas amount passing through all these holes is detected, therefore This is because the amount of gas passing through each hole cannot be detected.

[0004] In view of the above problems, an object of the present invention is to measure the diameter of each hole of a member having holes having different diameters.

[0005]

According to a first aspect of the present invention, there is provided a reservoir containing an incompressible fluid, and a pressure changing means for changing a pressure of the fluid in the reservoir. A fluid pressure detecting means for detecting a pressure of a fluid in the reservoir, and a fluid amount detecting means for detecting an amount of the fluid in the reservoir, wherein a member having holes having different diameters is provided in the reservoir. The fluid pressure in the reservoir is changed by the pressure changing means when the fluid is disposed in the fluid inside the fluid, and the fluid detected by the fluid pressure detecting means when the fluid amount in the reservoir is changed by the fluid amount detecting means. The hole diameter of the member is measured based on the pressure.

According to a second aspect, in the first aspect, the pressure changing means pressurizes the fluid in the reservoir,
The higher the fluid pressure detected when the amount of fluid in the reservoir changes, the smaller the diameter of the measured hole. According to a third aspect, in the first aspect, the member is a fuel injection valve of an internal combustion engine, and the hole is an injection hole of the fuel injection valve.

[Detailed Description of the Invention] A pore diameter measuring apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 shows a pore diameter measuring apparatus 1 of the present invention.
Is shown. The pore size measuring device 1 includes a reservoir 2 for containing and storing a liquid L used for measuring the pore size. The reservoir 2 has an inflow port 3 through which a liquid flows. In the present invention, the liquid used for measuring the pore size needs to have high surface tension, relatively low viscosity, and non-compressibility that is not compressed when pressed, and the liquid in this embodiment is mercury. However, other fluids having similar properties to mercury may be used.

The pore diameter measuring device 1 has a mercury tank 4 for storing mercury L. The mercury tank 4 has a liquid inlet 5 and a liquid outlet 6. The liquid outlet 6 is the inlet 3 of the reservoir 2
Connected to. The liquid inlet 5 is connected to a liquid pressurizing pipe 7. A pressurizer 8 for pressurizing the mercury L in the reservoir 3 is connected to the liquid pressurizing pipe 7. The pressurizer 8 has a pressurizing rod 9 inserted into the liquid pressurizing pipe 7. The pressurizer 8 presses the mercury in the reservoir 2 by moving the pressurizing rod 9 in the liquid pressurizing tube 7.

In this embodiment, a pressure sensor 10 is attached to the mercury tank 4. The pressure sensor 10 detects the pressure of mercury in the mercury tank 4 and therefore the pressure of mercury in the reservoir 2. Further, the hole diameter measuring device 1 of the present embodiment has a movement amount sensor 11 for detecting the movement amount of the pressure rod 9 in the pressure pipe 7. The pressure sensor 10 and the movement amount sensor 11 are connected to an electronic control unit (ECU) 12.

Next, the method for measuring the pore size of the present invention will be described. In this embodiment, an injection hole (hereinafter, referred to as an injection hole) of a tip nozzle of a fuel injection valve
The diameter of the hole is measured. The tip nozzle is shown in detail in FIGS. FIG. 2 is a sectional view of the tip nozzle 13.
The tip nozzle 13 has a hole group 14 composed of a plurality of holes. Referring to FIGS. 3 and 4, the hole group 14 includes three pairs of holes 14a, 14b, and 14c. The pair of holes 14a, 14b, 14c
Are formed point-symmetrically with respect to the axis A. Paired holes 1
The hole diameters da, db, dc of 4a, 14b, 14c are different for each pair. That is, the diameter da of the hole (hereinafter, first hole) 14a formed closest to the axis A of the tip nozzle 13 is a pair of holes (hereinafter, second hole) formed just outside the first hole 14a with respect to the axis A. The hole 14b is smaller than the diameter db. The diameter dc of a hole (hereinafter, referred to as a third hole) 14c formed just outside the second hole 14b with respect to the axis A is larger than the diameter db of the second hole 14b.

In the hole diameter measuring method of the present embodiment, first, the tip nozzle 13 having the hole group 14 as described above is disposed in the reservoir 2 as shown in FIG. That is, the tip nozzle 13 is immersed in mercury in the reservoir 2. At this time, the internal space of the reservoir 2 is the space occupied by the tip nozzle 13 itself and the holes 14a, 14a of the tip nozzle 13.
Except for the space inside b and 14c, it is completely filled with mercury L.

Next, the pressurizer 8 gradually pressurizes the mercury L in the reservoir 2 at a predetermined ratio. While the mercury L in the reservoir 2 is being pressurized, the pressure sensor 10 and the displacement sensor 11 continue to monitor the pressure in the reservoir 2 and the displacement of the pressure rod 9. The amount of movement of the pressure rod 9 is a value representing the amount of change in the amount of mercury in the reservoir 2.

Here, the principle underlying the pore diameter measuring method of the present invention will be described. As described above, the tip nozzle 13 is disposed in the reservoir 2, and when the mercury L in the reservoir 2 is not pressurized, mercury flows through the holes 14a, 14b,
It has not flowed into 14c. This is because the surface tension of mercury is large and the diameters da, db, of the holes 14a, 14b, 14c are large.
This is because dc is relatively small. Next, when the mercury in the reservoir 2 is gradually pressurized, the mercury flows into the holes 14a, 14b, 14c when the pressure of the mercury reaches a certain value. As described above, the pressure of mercury when mercury flows into the pores depends on the pore diameter and is inversely proportional to the pore diameter. That is, the pressure of mercury when mercury flows into the hole is lower as the hole diameter is larger. Therefore, the pore diameter can be measured based on the pressure of mercury when mercury flows into the pore. Since the amount of mercury in the reservoir 2 increases as a result of mercury flowing into the hole, in this embodiment, the mercury flows into the hole when the movement of the pressure rod 9 is detected by the moving amount sensor 11. Judge as time.

According to the above principle, in this embodiment, when the amount of mercury in the reservoir 2 is gradually increased, the amount of change in the amount of mercury P in the reservoir 2 detected by the pressure sensor 10 and the amount of mercury in the reservoir 2 detected by the displacement sensor 11 The relationship with ΔV is as shown in FIG. That is, the mercury pressure P becomes a certain pressure PcL
Is reached, the movement of the pressure rod 9 and hence the change in the amount of mercury in the reservoir 2 is detected. Next, when the mercury pressure P reaches a certain pressure PcH slightly higher than the pressure PcL, a change in the amount of mercury in the reservoir 2 is detected. In this embodiment, the average pressure Pc of these pressures PcL and PcH when the amount of mercury in the reservoir 2 changes is defined as the mercury pressure when mercury flows into the hole.

In this embodiment, the relationship between the mercury pressure (hereinafter referred to as mercury inflow pressure) P when mercury flows into the hole and the hole diameter d is previously stored in the electronic control unit 12 in the form of a map as shown in FIG. It is remembered. Therefore, the diameter dc of the third hole 14c is calculated based on the mercury inflow pressure Pc based on this map.
When the mercury pressure P in the reservoir 2 is further increased, a change in the amount of mercury in the reservoir 2 is detected at a pressure Pb higher than the mercury inflow pressure Pc, and the mercury amount in the reservoir 2 is further increased at a pressure Pa higher than the pressure Pb at this time. A change is detected. Then, based on these pressures Pb and Pa, the second holes 14 are formed.
The diameters db and da between b and the first hole 14a are calculated.

As described above, according to the present invention, different pore sizes can be easily measured. In this embodiment, the volume of each hole and the length of each hole can be additionally measured. That is, the amount of change in the amount of mercury in the reservoir 2 corresponding to each of the mercury inflow pressures Pa, Pb, and Pc is the volume of each hole, and the length of each hole can be measured by using this volume and the diameter of each hole. Can also.

In the above embodiment, the pressure of mercury in the reservoir is increased. First, mercury is allowed to flow into the hole of the tip nozzle, and then the pressure of mercury in the reservoir is reduced, and The pore size can be measured based on the mercury pressure when the amount of mercury changes.

[0018]

According to the first to third aspects of the invention, the pressure of the fluid in the reservoir is changed, and the hole diameter is measured based on the fluid pressure when the amount of fluid in the reservoir changes. That is, when the fluid pressure in the reservoir is changed, the amount of fluid in the reservoir changes due to the inflow of fluid into the hole or the outflow of fluid from the hole. As described above, the fluid pressure when the fluid flows into the hole or the fluid pressure when the fluid flows out of the hole is a value specific to the diameter of the hole. Therefore, the diameter of each hole of a member having a plurality of holes having different diameters can be measured based on the fluid pressure when the fluid flows into the hole or when the fluid flows out of the hole.

[Brief description of the drawings]

FIG. 1 is a view showing a pore size measuring device of the present invention.

FIG. 2 is a sectional view of a tip nozzle whose hole diameter is to be measured.

FIG. 3 is an enlarged view of a tip portion of the tip nozzle of FIG. 2;

FIG. 4 is a view along the line IV-IV in FIG. 3;

FIG. 5 is a diagram showing the relationship between mercury pressure and the amount of change in the amount of mercury in a reservoir.

FIG. 6 is a diagram showing a relationship between mercury pressure and pore diameter.

FIG. 7 is a diagram showing a relationship between a change amount of a mercury amount in a reservoir and a pore volume.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hole diameter measuring device 2 ... Reservoir 8 ... Pressurizer 10 ... Pressure sensor 11 ... Movement amount sensor 14a, 14b, 14c ... Hole

Claims (3)

[Claims] A reservoir containing an incompressible fluid;
Pressure changing means for changing the pressure of the fluid in the reservoir, fluid pressure detecting means for detecting the pressure of the fluid in the reservoir, and fluid amount detection for detecting the amount of the fluid in the reservoir Means, when a member having holes having different diameters is arranged in the fluid in the reservoir, the pressure of the fluid in the reservoir is changed by the pressure changing means, and the fluid amount detecting means changes the pressure in the reservoir. A hole diameter measuring device for measuring a diameter of a hole of the member based on a fluid pressure detected by the fluid pressure detecting means when a fluid amount changes. 2. The method according to claim 1, wherein the pressure changing means pressurizes the fluid in the reservoir, and the diameter of the hole measured decreases as the fluid pressure detected when the amount of fluid in the reservoir changes increases. Hole diameter measuring device. 3. The hole diameter measuring device according to claim 1, wherein the member is a fuel injection valve of an internal combustion engine, and the hole is an injection hole of the fuel injection valve.