JP2000145592A - Inspection method of and inspection device for fuel pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspection method of fuel pumps that can easily determine whether or not the internal surface of cylinders and the external surface of plungers have an appropriate clearance therebetween, and an inspection device for use in the inspection method. SOLUTION: A cylinder 12 defined in a pump body 11 of a fuel pump 10 is closed at one end and is filled with testing fluid. A plunger 13 is inserted in the other end of the cylinder 12 so as to thrust into it with an arbitrary load F. Once the pressure ΔP of a space (high-pressure chamber) 14 that is filled with the testing fluid and the pressing load F of the plunger 13 becomes balanced with each other, measurement is made of the flow quantity Q of the testing fluid passing between the internal surface of the cylinder 12 and the external surface of the plunger 13 as well as the balancing pressure ΔP or load F. The clearance (h) between the internal surface of the cylinder 12 and the external surface of the plunger 13 is derived from these measured flow quantity Q, and pressure ΔP or load F, and then checked against a criterion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel pump in which a plunger is inserted into a cylinder so as to be reciprocally movable. The present invention relates to an inspection method and an inspection device used for the inspection method.

[0002]

2. Description of the Related Art As is well known, in an internal combustion engine such as an in-vehicle engine, a fuel pump used for supplying the fuel is usually slidably inserted into a pump body having a cylinder formed therein. A cylindrical plunger. The plunger reciprocates in the cylinder in the axial direction thereof, for example, by being pressed by a cam which is drivingly connected to the output shaft of the internal combustion engine, and being urged by a coil spring or the like in a direction against the pressing. become.

On the other hand, a first fuel passage (input passage) connected to a fuel tank and the like is provided in a cylinder of the pump body, and a pump chamber whose volume changes with reciprocation of a plunger is provided. I have. The pump chamber is provided with a second fuel passage (output passage) connected to a delivery pipe, a fuel injection valve, or the like.

[0004] When the plunger moves in a direction to increase the volume of the pump chamber, the first fuel passage communicates with the pump chamber, and fuel in the fuel tank enters the pump chamber via the first fuel passage. be introduced. Conversely, when the plunger moves in the direction in which the volume of the pump chamber decreases, the first fuel passage and the pump chamber are shut off, and the fuel in the pump chamber is pressurized. The fuel is sent to a delivery pipe or a fuel injection valve through the second fuel passage.

[0005] The performance and durability of such a fuel pump are greatly affected by the clearance between the inner peripheral surface of a cylinder formed in the pump body and the outer peripheral surface of a plunger inserted therein. For this reason, the clearance needs to satisfy strict dimensional tolerances. In manufacturing the fuel pump, an appropriate combination capable of satisfying such dimensional tolerances is selected from a plurality of pump bodies and plungers. .

On the other hand, in order to select a combination of the pump body and the plunger in this way, it is necessary to inspect the suitability of the clearance for each of the combined pump body and plunger. The clearance is usually 2 to 4 μm.
Is extremely small, it is not possible to determine the suitability by actually measuring the dimensions.

Therefore, conventionally, a test fluid such as gas or liquid is fed into the fuel pump with the plunger inserted into a cylinder of the pump body, and passes between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger. A method has been considered in which the flow rate of the test fluid to be measured is measured to determine whether the clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger is appropriate.

As one example, for example, Japanese Patent Application Laid-Open No. 6-235
In the inspection method described in JP-A-362-362, the sealing performance of an O-ring (O-ring) for separating a lubricating oil space and a fuel space is inspected rather than the suitability of the clearance. A gas pressure difference is formed between the space and the space, and a gas leakage amount (flow rate) based on the pressure difference is measured to determine whether the gas leakage is appropriate.

In this case, whether the clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger is appropriate is slightly different, and although the sealing performance of the O-ring is determined, the pressure difference between the two spaces is determined. This is a method for judging the suitability of the gap separating these spaces based on the leakage amount (flow rate) of the test fluid caused by the above, and it is easy to apply this to the judgment of the suitability of the clearance.

[0010]

As described above, the test fluid is fed into the fuel pump with the plunger inserted into the cylinder of the pump body, and the space between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger is formed. By measuring the flow rate of the test fluid passing therethrough, it is possible to determine whether the clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger is appropriate.

However, in the case of the inspection method, it is necessary to feed the test fluid into the fuel pump, and it is necessary to appropriately manage the pressure of the sent test fluid. Has become inevitable.

The present invention has been made in view of such circumstances, and a fuel pump inspection method capable of more easily determining the suitability of the clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger. And an inspection apparatus used for the inspection method.

[0013]

According to the first aspect of the present invention, as a method of inspecting a fuel pump, one end of a cylinder formed in a pump main body of a fuel pump is sealed and a test fluid is inspected. While the plunger is inserted from the other end and pressed with an arbitrary load, and when the pressure of the space filled with the test fluid and the pressing load of the plunger are balanced, the inner peripheral surface of the cylinder and The clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger is determined based on the flow rate of the test fluid passing between the outer peripheral surface of the plunger and the balanced pressure or load to determine whether the clearance is appropriate. I decided to.

As described above, when the plunger is inserted from the other end into the cylinder filled with the test fluid in the closed space and the cylinder is filled with the test fluid and pressed with an arbitrary load, the pressure in the space is reduced. When the space rises and the space is compressed by a predetermined amount, the pressure (precisely, a value obtained by multiplying the generated pressure by the cross-sectional area of the plunger) and the pressing load of the plunger come to balance. After the balance is obtained in this way, the flow rate of the test fluid passing between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger also becomes a constant amount per time, corresponding to the clearance between them. . At this time, the clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger is determined in accordance with the ratio between the flow rate of the test fluid and the pressure generated in the space. In other words, if the flow rate of the test fluid and the pressure generated in the space are measured,
The same clearance is required in accordance with the ratio of the measured values.

The pressure generated in the space after the balance is obtained is also a value obtained by dividing the pressing load of the plunger by the cross-sectional area of the plunger, and this pressing load is measured instead of the generated pressure. Of course, it may be done.

In any case, according to the inspection method of the first aspect of the present invention, the clearance can be determined without sending the test fluid into the fuel pump or controlling the pressure of the sent test fluid. As a result, the suitability of the clearance can be determined more easily and accurately.

According to the second aspect of the invention, as a fuel pump inspection method, one end of a cylinder formed in a pump body of the fuel pump is sealed and filled with a test fluid, and a plunger is inserted from the other end. It is inserted and pressed with an arbitrary load, and passes between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger when the pressure of the space filled with the test fluid and the pressing load of the plunger are balanced. The step of determining the clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the flow rate of the test fluid and the balanced pressure or load corresponds to each different relative angle between the cylinder and the plunger. A plurality of times, and the suitability is determined based on the obtained values of the plurality of clearances.

According to the inspection method of the second aspect of the present invention, the clearance can be obtained without sending the test fluid into the fuel pump or controlling the pressure of the sent test fluid, as described above. As a result, the suitability of the clearance can be determined more easily and accurately.

In the inspection method, the accuracy of the determination is further improved by performing the calculation of the clearance based on the measured values at a plurality of positions corresponding to different relative angles between the cylinder and the plunger. Become so.

By the way, if a plurality of data on the clearance is obtained at different relative angles between the cylinder and the plunger, that is, at different relative positions with respect to the rotation direction of the cylinder and the plunger, the axes of the cylinders and the plungers are mutually aligned. Even in the case where the clearances are shifted or the radial cross sections of both of them are not perfect circles, it is possible to determine whether the clearance is appropriate or not, including the actual state thereof.

In the inspection method according to the first and second aspects of the present invention, the measured flow rate of the test fluid is:
When the test fluid is a liquid, any value can be used as long as it is a value obtained corresponding to the clearance, such as the weight passing through the clearance per unit time, and these can be appropriately used.

According to a third aspect of the present invention, as a fuel pump inspection method, one end of a cylinder formed in a pump body of the fuel pump is sealed and filled with a test fluid, and a plunger is inserted from the other end. Insert and press with an arbitrary load, and determine the flow rate of the test fluid passing between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the amount of movement of the plunger and the time required for the movement. A clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger is determined based on the determined flow rate and the pressure of the space filled with the test fluid or the pressing load of the plunger to determine whether the clearance is appropriate. It shall be.

When the plunger is inserted from one end into the cylinder filled with the test fluid in one closed end and is pressed with an arbitrary load, the amount of movement of the plunger is as described above. Also, the flow rate of the test fluid passing between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger can be determined based on the time required for the movement. That is, in this case, the compression amount of the space is a value obtained by multiplying the movement amount of the plunger by the cross-sectional area of the plunger.
By dividing the amount of space compression by the time required for the movement of the plunger, the flow rate of the test fluid can be obtained. If the flow rate of the test fluid is obtained in this way, the generated flow rate and the measured values are measured by measuring the generated pressure in the space or the pressing load of the plunger as in the invention described in claim 1 above. The clearance can be obtained as a value corresponding to the ratio.

Therefore, according to the inspection method of the third aspect of the present invention, the clearance is required without sending the test fluid into the fuel pump or controlling the pressure of the sent test fluid. In addition, the suitability of the clearance can be determined more simply and accurately. In addition, in the case of the inspection method, it is not necessary to measure the flow rate of the test fluid.

According to a fourth aspect of the present invention, as a fuel pump inspection method, one end of a cylinder formed in a pump body of the fuel pump is sealed and filled with a test fluid, and a plunger is inserted from the other end. Insert and press with an arbitrary load, and determine the flow rate of the test fluid passing between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the amount of movement of the plunger and the time required for the movement. Determining the clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the determined flow rate and the pressure of the space filled with the test fluid or the pressing load of the plunger. Perform a plurality of times corresponding to each different relative angle with the plunger, and determine the suitability based on the obtained values of the plurality of clearances And the.

According to the inspection method of the fourth aspect of the invention, similarly to the third aspect of the invention, the test fluid is not fed into the fuel pump and the pressure of the fed test fluid is not controlled. Furthermore, it is not necessary to measure the flow rate of the test fluid, and the clearance is required, so that the suitability of the clearance can be more easily determined.
Moreover, it is possible to make an accurate determination.

Further, in the inspection method, the accuracy of the determination is further improved by calculating the clearance at a plurality of positions corresponding to different relative angles of the cylinder and the plunger.

If a plurality of data relating to the clearance is to be obtained at different relative angles between the cylinder and the plunger, that is, at different relative positions with respect to the rotational direction of the cylinder and the plunger, the axes of the cylinders and the plungers are shifted from each other. As described above, it is also possible to determine whether or not the clearance is appropriate, including the actual state thereof, in the case where the radial cross sections of both of them are not a perfect circle.

According to a fifth aspect of the present invention, in the fuel pump inspection method according to any one of the first to fourth aspects, the temperature of the test fluid is detected and the test used for calculating the clearance is performed. The flow rate value of the fluid is corrected based on the detected temperature value.

Usually, the viscosity of the test fluid changes with a change in temperature, and the flow rate passing through the clearance also changes due to the change in the viscosity. Therefore,
According to such an inspection method of the invention as set forth in claim 5, wherein the temperature of the test fluid is detected and the flow rate value is corrected by the detected temperature, the temperature affecting the flow rate of the test fluid passing through the clearance is determined. The effect can be accurately compensated. Therefore, for the same clearance, the same determination result can be obtained regardless of the temperature change of the test fluid,
The accuracy of the determination is also improved.

According to a sixth aspect of the present invention, as a fuel pump inspection method, one end of a cylinder formed on a pump main body of a fuel pump and having an inner peripheral surface coated with a test fluid is opened and the other end is opened. The plunger is inserted from the end and pressed with a constant load. Based on the moving speed of the plunger at that time, the clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger is determined to determine whether the clearance is appropriate. .

In the fuel pump in which the test fluid is applied to the inner peripheral surface of the cylinder as described above, the test fluid interposed between the cylinder and the plunger has a shear force accompanying insertion and pressing of the plunger. Power works. And
This shearing force is approximately proportional to the ratio between the insertion speed (moving speed) of the plunger and the film thickness of the test fluid.

Therefore, if the thickness of the test fluid is considered as a clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger, and the shearing force is regarded as the constant pressing load of the plunger, the sixth aspect of the present invention is described. The clearance (film thickness of the test fluid) can be obtained by measuring the moving speed of the plunger as in the inspection method of the invention described.

According to the inspection method of the present invention, the clearance is required without sending the test fluid into the fuel pump or controlling the pressure of the sent test fluid. ,
Appropriateness of the clearance can be determined more easily and accurately.

According to a seventh aspect of the present invention, as a fuel pump inspection method, one end of a cylinder formed on a pump body of the fuel pump and having an inner peripheral surface coated with a test fluid is opened, and the other end is opened. A step of inserting the plunger from the end and pressing the same with a constant load, and obtaining a clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the moving speed of the plunger at that time, includes the steps of: It is performed a plurality of times corresponding to each different relative angle, and the suitability is determined based on the obtained values of the plurality of clearances.

According to the inspection method of the present invention, the test fluid is not fed into the fuel pump and the pressure of the fed test fluid is not controlled, similarly to the invention of the sixth aspect. The clearance is required, and the suitability of the clearance can be determined more easily and accurately.

Further, in the inspection method, the accuracy of the determination can be further improved by calculating the clearance at a plurality of positions corresponding to different relative angles between the cylinder and the plunger.

If a plurality of data relating to the clearance is obtained at different relative angles between the cylinder and the plunger, that is, at different relative positions with respect to the rotational directions of the cylinder and the plunger, the axes of the cylinders and the plungers are shifted from each other. As described above, it is also possible to determine whether or not the clearance is appropriate, including the actual state thereof, in the case where the radial cross sections of the two are not perfectly circular.

According to the invention of claim 8, as a fuel pump inspection method, one end of a cylinder formed on a pump body of the fuel pump and having a test fluid applied to an inner peripheral surface thereof is opened, and the other end is opened. The plunger is inserted from the end and pressed at a constant speed, and based on the pressing load of the plunger at that time, the clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger is determined to determine whether the clearance is appropriate. .

As described above, in the fuel pump in which the test fluid is applied to the inner peripheral surface of the cylinder, the test fluid interposed between the cylinder and the plunger includes: A shearing force is generated due to the insertion and pressing of the plunger. The shear force is generally proportional to the ratio between the insertion speed (movement speed) of the plunger and the thickness of the test fluid.

Therefore, in this case, if the film thickness of the test fluid is considered as a clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger, and the shearing force is regarded as a pressing load of the plunger, the present invention is described in claim 8. As described above, by pressing the plunger at a constant speed and measuring the pressing load of the plunger at that time, the clearance (film thickness of the test fluid) can be obtained.

According to the inspection method of the present invention, the clearance is required without sending the test fluid into the fuel pump or controlling the pressure of the sent test fluid. ,
Appropriateness of the clearance can be determined more easily and accurately.

According to a ninth aspect of the present invention, as a method of inspecting a fuel pump, one end of a cylinder formed on a pump body of the fuel pump and having an inner peripheral surface coated with a test fluid is opened and the other end is opened. The step of inserting the plunger from the end and pressing at a constant speed, and obtaining a clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the pressing load of the plunger at that time includes the steps of: It is performed a plurality of times corresponding to each different relative angle, and the suitability is determined based on the obtained values of the plurality of clearances.

According to the inspection method of the ninth aspect of the invention, similarly to the eighth aspect of the invention, the test fluid is not fed into the fuel pump and the pressure of the fed test fluid is not controlled. The clearance is required, and the suitability of the clearance can be determined more easily and accurately.

Further, in the inspection method, the accuracy of the determination is further improved by calculating the clearance at a plurality of positions corresponding to different relative angles of the cylinder and the plunger.

As described above, if a plurality of data relating to the clearance is to be obtained at different relative angles between the cylinder and the plunger, that is, at different relative positions with respect to the rotation direction of the cylinder and the plunger, the cylinder and the plunger can be obtained. Even in the case where the axes are shifted from each other or the radial cross sections of both of them are not a perfect circle, the appropriateness of the clearance can be determined including the actual state thereof.

According to a tenth aspect of the present invention, in the fuel pump inspection method according to any one of the sixth to ninth aspects, the temperature of the test fluid is detected, and the value of the clearance determined is detected. It is to be corrected based on the temperature value.

As described above, the viscosity of a test fluid usually changes with a change in temperature. Further, the shear force also changes due to the change in the viscosity. Therefore, according to such an inspection method of the invention as set forth in claim 10, wherein the temperature of the test fluid is detected and the value of the required clearance is corrected by the detected temperature, the viscosity of the test fluid, and hence the shearing force, is obtained. Temperature can be accurately compensated for. Therefore, the same determination result can be obtained for the same clearance regardless of a change in the temperature of the test fluid, and the determination accuracy is improved.

In the inspection method according to the first to tenth aspects of the present invention, the clearance to be determined does not necessarily need to be the value of the clearance itself, but may be a value corresponding to the clearance. Shall be included. The point is that the clearance or its corresponding value may be used. For example, according to the first aspect of the present invention, the flow rate of the test fluid, the pressure in the space filled with the test fluid, the pressing load of the plunger, and the like also become the clearance corresponding values.

On the other hand, according to the invention of claim 11, as a fuel pump inspection device, means for inserting a plunger with an arbitrary load from the other end into a cylinder of a fuel pump filled with a test fluid with one end sealed. Means for measuring the flow rate of the test fluid passing between the inner peripheral surface of the cylinder of the fuel pump and the outer peripheral surface of the plunger; and any one of a pressure in a space filled with the test fluid and a pressing load of the plunger. Means for measuring one or the other, based on the flow rate of the test fluid to be measured and the pressure of the space filled with the test fluid or the pressing load of the plunger, the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger. Means for calculating the clearance between, and means for determining the suitability of the clearance based on the value of the calculated clearance,
The configuration is provided with.

As described in the first aspect of the present invention, one end is sealed, and a plunger is inserted from the other end into a cylinder filled with a test fluid in the sealed space and pressed with an arbitrary load. Then, when the pressure in the space increases and the space is compressed by a predetermined amount, the pressure (accurately, a value obtained by multiplying the generated pressure by the cross-sectional area of the plunger) and the pressing load of the plunger are balanced. become. After the balance is obtained in this manner, the internal pressure of the cylinder corresponds to the ratio of the flow rate of the test fluid passing between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger to the pressure generated in the space. Clearance between the peripheral surface and the outer peripheral surface of the plunger is required.

As described above, the pressure generated in the space after the balance is obtained is also a value obtained by dividing the pressing load of the plunger by the cross-sectional area of the plunger. Alternatively, the pressing load may be measured.

Therefore, according to the eleventh aspect of the present invention, the clearance is required without sending the test fluid into the fuel pump or controlling the pressure of the sent test fluid. ,
Appropriateness of the clearance can be determined more easily and accurately. And according to the same configuration,
The inspection method according to the first aspect of the present invention can be accurately executed.

In the inspection apparatus according to the eleventh aspect of the present invention, the flow rate of the test fluid to be measured may be, for example, the weight of the test fluid which is a liquid, such as the weight passing through the clearance per unit time. Any value can be used as long as the value can be obtained corresponding to the clearance, and these can be appropriately used.

According to the twelfth aspect of the present invention, as the fuel pump inspection device, a means for inserting a plunger with an arbitrary load from the other end into a cylinder of the fuel pump which is sealed at one end and filled with a test fluid. Means for measuring the amount of movement of the plunger, means for measuring the time required for the movement of the plunger, and the inner peripheral surface of the cylinder and the plunger based on the amount of movement of the plunger measured and the time required. Means for calculating the flow rate of the test fluid passing between the test fluid and the outer peripheral surface of the test fluid; means for measuring one of the pressure of the space filled with the test fluid and the pressing load of the plunger; The inner peripheral surface of the cylinder and the plunger based on the pressure of the space filled with the fluid or the pressing load of the plunger and the calculated flow rate of the test fluid. Means for calculating a clearance between the outer peripheral surface, a structure comprising, means for determining the appropriateness of the clearance on the basis of the value of the clearance which this is calculated.

As described in the third aspect of the present invention, one end is sealed, and a plunger is inserted from the other end into a cylinder filled with the test fluid in the sealed space and pressed with an arbitrary load. In such a case, the flow rate of the test fluid passing between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger can be determined based on the amount of movement of the plunger and the time required for the movement. That is, in this case, since the amount of compression of the space is a value obtained by multiplying the amount of movement of the plunger by the cross-sectional area of the plunger, the amount of space compression is divided by the time required for the movement of the plunger to obtain the test fluid. Is obtained. Then, if the flow rate of the test fluid is obtained in this manner, the pressure corresponding to the ratio between the obtained flow rate and the measured value is measured by measuring the generated pressure in the space or the pressing load of the plunger in the same manner as described above. The above clearance can be obtained.

Therefore, according to the configuration of the twelfth aspect of the present invention, the clearance is required without sending the test fluid into the fuel pump or controlling the pressure of the sent test fluid. Appropriateness of the clearance can be determined more easily and accurately. Further, in the case of the same configuration, it is not necessary to measure the flow rate of the test fluid. According to this configuration, the inspection method according to the third aspect of the present invention can be accurately executed.

According to a thirteenth aspect of the present invention, in the fuel pump inspection apparatus according to the eleventh or twelfth aspect,
The fuel pump further comprises means for displacing a relative angle between the cylinder and the plunger, wherein the means for calculating the clearance comprises: the clearance corresponding to the plurality of displaced relative angles between the cylinder and the plunger. Is calculated, and the means for determining the suitability of the clearance determines the suitability of the clearance based on the calculated values of the plurality of clearances.

According to this configuration of the invention, since the clearance is calculated at a plurality of positions corresponding to different relative angles between the cylinder and the plunger, the accuracy of the determination is further improved. Become. According to the configuration, the inspection method according to the second or fourth aspect of the invention can be executed accurately.

It is to be noted that if a plurality of data on the clearance is obtained at different relative angles between the cylinder and the plunger, that is, at different relative positions with respect to the rotational directions of the cylinder and the plunger, the axes of the cylinders and the plungers may be different from each other. As described above, it is possible to determine whether the clearance is appropriate or not, even when the gaps are deviated or when the radial cross sections of both of them are not a perfect circle.

According to a fourteenth aspect of the present invention, in the fuel pump inspection apparatus according to any one of the eleventh to thirteenth aspects, the fuel pump inspection apparatus further comprises means for detecting the temperature of the test fluid, and means for calculating the clearance. Is to calculate the clearance by correcting the flow rate value of the test fluid used for calculating the clearance based on the detected temperature value.

According to the above configuration, it is possible to accurately compensate for the temperature affecting the flow rate of the test fluid passing through the clearance. Therefore, the same determination result can be obtained for the same clearance regardless of a change in the temperature of the test fluid, and the determination accuracy is improved. Further, according to the configuration, the inspection method according to the invention described in claim 5 can be accurately executed.

In the fuel pump inspection apparatus according to the fifteenth aspect, the plunger is applied with a constant load from the other end to the cylinder of the fuel pump having one end opened and the test fluid applied to the inner peripheral surface. Means for inserting, means for measuring the moving speed of the inserted plunger, and the movement of the inner circumference of the cylinder and the outer circumference of the plunger based on the measured moving speed of the plunger and the constant insertion load. A means for calculating the clearance between the two and a means for determining whether the clearance is appropriate based on the calculated value of the clearance are provided.

As described above, in the fuel pump in which the test fluid is applied to the inner peripheral surface of the cylinder, the test fluid interposed between the cylinder and the plunger includes: A shear force comes to work with the insertion of the plunger. This shear force is generally proportional to the ratio between the insertion speed (movement speed) of the plunger and the film thickness of the test fluid.

Therefore, if the thickness of the test fluid is considered as a clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger, and the shearing force is regarded as the constant insertion load of the plunger, the present invention is applied to the present invention. As described above, the clearance (the thickness of the test fluid) can be obtained by measuring the moving speed of the plunger.

According to the above construction, the clearance is required without sending the test fluid into the fuel pump or controlling the pressure of the sent test fluid. Appropriateness of the clearance can be determined more easily and accurately. Further, according to the configuration, the inspection method according to the invention described in claim 6 can be accurately executed.

According to the present invention, as a fuel pump inspection device, the plunger is moved at a constant speed from the other end to the fuel pump cylinder having one end opened and the test fluid applied to the inner peripheral surface. Means for inserting, means for measuring the pressing load of the inserted plunger, and the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the measured pressing load of the plunger and the constant insertion speed. A means for calculating the clearance between the two and a means for determining whether the clearance is appropriate based on the calculated value of the clearance are provided.

In the fuel pump in which the test fluid is applied to the inner peripheral surface of the cylinder, the test fluid interposed between the cylinder and the plunger exerts a shearing force due to the insertion and pressing of the plunger, As described above, the shearing force becomes approximately proportional to the ratio between the insertion speed (moving speed) of the plunger and the film thickness of the test fluid.

Therefore, in this case, if the film thickness of the test fluid is considered as a clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger, and the shearing force is regarded as a pressing load of the plunger, the present invention is described in claim 16. As described above, by pressing the plunger at a constant speed and measuring the pressing load of the plunger at that time, the clearance (film thickness of the test fluid) can be obtained.

According to the above construction, the clearance is required without sending the test fluid into the fuel pump or controlling the pressure of the sent test fluid. Appropriateness of the clearance can be determined more easily and accurately. Further, according to the configuration, the inspection method according to the invention described in claim 8 can be accurately executed.

According to a seventeenth aspect of the present invention, in the fuel pump inspection apparatus according to the fifteenth or sixteenth aspect,
The fuel pump further comprises means for displacing a relative angle between the cylinder and the plunger, wherein the means for calculating the clearance comprises: the clearance corresponding to the plurality of displaced relative angles between the cylinder and the plunger. Is calculated, and the means for determining the suitability of the clearance determines the suitability of the clearance based on the calculated values of the plurality of clearances.

According to this configuration of the invention, the calculation of the clearance (film thickness of the test fluid) is performed at a plurality of positions corresponding to different relative angles between the cylinder and the plunger, so that the determination accuracy can be improved. Is further improved. According to the configuration, the inspection method according to the invention described in claim 7 or 9 can be accurately executed.

As described above, if a plurality of data relating to the clearance is to be obtained at different relative angles between the cylinder and the plunger, that is, at different relative positions with respect to the rotation direction of the cylinder and the plunger, the cylinder and the plunger can be obtained. In the case where the axes are displaced from each other or the radial cross-sections of the two are not true circles, it is possible to determine the appropriateness of the clearance including the actual state thereof.

In the invention according to claim 18, in the fuel pump inspection apparatus according to any one of claims 15 to 17, means for detecting the temperature of the test fluid is further provided, and means for calculating the clearance. Is to calculate the clearance value to be calculated as a value corrected based on the detected temperature value.

According to the above configuration, it is possible to accurately compensate for the viscosity of the test fluid and the temperature affecting the shearing force. Therefore, the same determination result can be obtained for the same clearance regardless of a change in the temperature of the test fluid, and the determination accuracy is improved. Further, according to the configuration, the inspection method according to the tenth aspect of the present invention can be accurately executed.

In the inspection apparatus according to the present invention, the clearances to be obtained do not necessarily have to be the values of the clearances themselves, but may be any values corresponding to the clearances. It shall be included as appropriate. The point is that the clearance or its corresponding value may be used. For example, in the case of the invention described in claim 11, the flow rate of the test fluid, the pressure in the space filled with the test fluid, the pressing load of the plunger, and the like are also values corresponding to the clearance.

[0077]

(First Embodiment) FIG. 1 shows a specific configuration of a first embodiment of a fuel pump inspection apparatus according to the present invention.

First, the structure of a fuel pump to be inspected in the inspection apparatus of this embodiment will be briefly described. As shown in FIG. 1, the fuel pump 10 has a cylinder 12 formed in a cylindrical pump body 11, and a cylindrical plunger 13 is slidably inserted into the cylinder 12. Become.

In the fuel pump 10, the other end of the pump body 11 into which the plunger 13 is inserted is sealed with a suitable jig (not shown). The partitioned space 14 is a high-pressure chamber filled with the test fluid, as described later. That is, the high-pressure chamber 14 corresponds to the pump chamber, and the second fuel passage serving as the output passage is closed by the jig. Note that, as the test fluid, in the inspection apparatus of the embodiment, for example, CC
A liquid having properties similar to gasoline fuel such as F (carburetor control fluid) is used.

On the other hand, in the fuel pump 10, an annular groove 15 is formed in the middle of the cylinder 12 of the pump body 11, and a space 16 formed in the annular groove 15 is formed in a low-pressure chamber. Becomes And the pump body 11
The fuel pump 17 is provided with a fuel passage 17 communicating with the low-pressure chamber 16. When the fuel pump 10 is actually used, the fuel passage 17 serves as the first fuel passage which is an input passage. However, as will be described later, in the inspection apparatus according to the present embodiment, the fuel passage 17 serves as a discharge port of the test fluid, and the inside of the cylinder 12 based on the pressure difference between the high-pressure chamber 14 and the low-pressure chamber 16. The test fluid passing through the clearance between the peripheral surface and the outer peripheral surface of the plunger 13 is discharged outside through the fuel passage 17.

The high-pressure chamber 14 of the cylinder 12
Is an enlarged diameter portion 1 whose inner peripheral surface is enlarged.
2 ', and as long as the tip of the plunger 13 projects from the enlarged diameter portion 12' in the manner shown in FIG. 1, the substantial sliding length of the plunger 13 and the subsequent inspection The axial length (movement distance of the test fluid) L of the clearance to be subjected to the above is constant.

The inspection apparatus according to this embodiment determines whether or not the clearance between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13 is appropriate for the fuel pump 10 having such a structure as an inspection target. As shown in FIG.
0, a measurement and control unit 40, and a driving unit 50.

Here, the detecting unit 30 determines the temperature of the test fluid filled in the high-pressure chamber 14 of the fuel pump 10, the pressure in the high-pressure chamber 14, the high-pressure chamber 14 and the low-pressure chamber 16
This is a part for detecting the weight of the test fluid discharged from the fuel passage 17 through the clearance between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13 based on the pressure difference between the test fluid and the test fluid. Specifically, a temperature sensor 31 for detecting the temperature of the test fluid filled in the high-pressure chamber 14, a pressure sensor 32 for detecting the pressure in the high-pressure chamber 14, and the fuel passage 17
The detection unit 30 is provided with a weight sensor (electronic balance) 33 for detecting the weight of the test fluid discharged from the apparatus.
The weight sensor 33 includes a beaker 33a for storing the discharged test fluid.

The measurement and control unit 40 fetches various values detected through the detection unit 30, and (a) measures the flow rate of the test fluid. (B) Measurement of the pressure in the high-pressure chamber 14. (C) Correction of the flow measurement value based on the temperature change of the test fluid. And (d) calculating the clearance based on the corrected flow measurement value and the pressure measurement value, and determining whether or not the clearance is appropriate. And controls the drive mode of the drive unit 50 described below. The measurement and control unit 40 specifically includes the processes (a) to (d) and the driving unit 50
And a monitor (display) 42 for visually displaying the measurement results, judgment results, and the like.

Then, the driving unit 50 performs the plunger 1 of the fuel pump 10 when performing the inspection by the inspection apparatus.
While supporting the plunger 3, the plunger 13 is pressed by an arbitrary load F under the control of the computer 41 (measurement and control unit 40) in a manner indicated by an arrow in FIG.
This portion variably sets the relative angle between the cylinder 12 (pump body 11) and the plunger 13. In the inspection apparatus of the embodiment, the pump main body 11 of the fuel pump 10 is fixed and supported by an appropriate jig (not shown). With respect to such a pump body 11, the driving unit 50 includes a moving actuator 52 that presses the plunger 13 in the above-described manner while moving the plunger 13 along the rail 51 in the axial direction, and a moving actuator 52
, The plunger 13 being displaced in a rotational direction about the axis thereof.
3 is provided. The rotation shaft 53a of the rotation actuator 53 is connected to one end of the plunger 13 via a chuck 54, and the plunger 13
Is driven by the actuators 52 and 53, and is freely displaced in the cylinder 12 in the axial direction and the rotational direction about the axis.

FIGS. 2 and 3 show an example of a fuel pump inspection procedure performed by using such an inspection apparatus. Next, referring to FIGS. 2 and 3, FIG. A fuel pump inspection method using the inspection device according to the embodiment will be described in detail.

In this inspection method, as shown in FIG. 1, the plunger 13 is opened from the open end of the cylinder 12 of the pump body 11 with the test fluid filled in the cylinder 12, especially the enlarged diameter portion 12 'thereof. , And pressed with an arbitrary load F through the driving unit 50.

At this time, the pressure in the high-pressure chamber 14 temporarily increases, but when the pressure is compressed by ΔV with respect to the total volume V, the pressure and the pressing load F
And become balanced. That is, the plunger 1
The pressure generated in the high-pressure chamber 14 due to the pressing of the pressure 3 is ΔP, the sectional area of the plunger 13 is Ap, and the bulk modulus of the test fluid is K.
When t, between the pressing load F and the generated pressure ΔP in the high-pressure chamber 14 or the compression amount ΔV with respect to the total volume V in the high-pressure chamber 14, ΔPAp = (ΔV / V) KtAp = F (1) ) Is established.

After the balance is obtained in this way, the flow rate of the test fluid passing between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13 also corresponds to the amount of time per hour corresponding to the clearance between the two. It will be a certain amount. Moreover, at this time, the flow rate of the test fluid and the high pressure chamber 14
The clearance between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13 is determined in accordance with the ratio of the generated pressure to the inner pressure.

That is, in such a fuel pump 10, the volume flow rate of the test fluid passing through the clearance between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13 is represented by Q: Q = K ( πdh ^ 3 / 12μL) ΔP (2) where K: relative position coefficient d: plunger diameter h: clearance μ: fluid viscosity L: fitting length (length of the clearance in the axial direction) ΔP: high-pressure chamber pressure , “^” Is a power, and “^ 3” is a power of three. Therefore, the flow rate Q of the test fluid after the above-mentioned balancing and the generated pressure ΔP in the high-pressure chamber 14
Is determined as follows: h ^ 3 = (Q / ΔP) (1 / K) (12 μL / πd) = (Q / ΔP) × constant (3) Become.

However, in the above equation (2), the fluid viscosity μ is a value that changes according to the temperature of the same fluid (test fluid), and actually, Q (reference temperature) / Q (measured temperature) = μ (Measured temperature) / μ (reference temperature) = A (4) The flow rate Q changes by the ratio A.

Therefore, in this embodiment, the flow rate Q to be measured is subjected to temperature correction in the form of Q ← Q · A (5).

Then, the clearance h is calculated based on the value of the flow rate Q subjected to the temperature correction and the measured value of the generated pressure ΔP in the high-pressure chamber 14, and the propriety of the clearance h is determined based on the calculated value of the clearance h. judge.

Further, the calculation of the clearance h is as follows.
The operation is performed at a plurality of positions corresponding to different relative angles between the cylinder 12 and the plunger 13 displaced through the driving unit 50.

Incidentally, here, as for the rotation direction about the axis of the cylinder 12 and the plunger 13, the relative angle between the cylinder 12 and the plunger 13 is expressed as
Four angles of 0 °, 90 °, 180 °, and 270 ° are set.

Hereinafter, the inspection method will be described in detail according to the inspection procedure (FIGS. 2 and 3) executed by the computer 41 of the measurement and control unit 40. In the inspection, first, the plunger 13 is inserted from the open end of the cylinder 12 in a state where the enlarged diameter portion 12 ′ of the cylinder 12 is filled with the test fluid.
The relative angle between the piston and the plunger 13 is set to “0 °” (Step S110 in FIG. 2).

Thereafter, the plunger 13 is pressed with an arbitrary load F through the drive unit 50 (step S in FIG. 2).
120), the presence or absence of the above-mentioned balance, ie, the above (1)
It is confirmed whether or not the formula is satisfied (step S121 in FIG. 2).
Incidentally, this can be confirmed based on the fact that the output of the pressure sensor 32 is monitored and the value converges to a constant value.

After the balance is thus obtained, the generated pressure ΔP in the high-pressure chamber 14 is measured based on the output of the pressure sensor 32 (step S130 in FIG. 2), and then the gas leaks out through the fuel passage 17. While sampling the test fluid with the beaker 33a, the process waits for the elapse of a predetermined time (time at which a testable flow rate of the test fluid is obtained) (step S2 in FIG. 2).
140) In the meantime, the temperature of the test fluid in the high-pressure chamber 14 is measured by the temperature sensor 31.

A temperature correction value A for the test fluid is calculated based on the measured temperature value. (Steps S141 and S142 in FIG. 2). The calculation of the temperature correction value A is performed based on the above equation (4). However, the calculation method is arbitrary, and the reference value and the measured value are directly substituted into the equation (4) to calculate the correction value A.
Alternatively, the transition tendency of the same correction value A corresponding to each measurement value is obtained in advance as a map, and this correction value A is obtained from each measurement value by map calculation including interpolation. You may do so.

When the temperature correction value A is obtained in this way, when the predetermined time elapses, the temperature correction value A passes between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13 per predetermined time based on the value measured by the weight sensor 33. (Fuel passage 1
2 is calculated (FIG. 2).
Step S150).

When calculating the flow rate Q, as shown in FIG. 3, the weight W per predetermined time is measured. That is, the weight W of the test fluid stored in the beaker 33a at that time.
Is measured by the weight sensor 33, and the measured value is divided by the predetermined time to calculate the weight W per the predetermined time.

The weight per predetermined time W is divided by the density of the test fluid to convert it into a flow rate Q. Are executed (steps S151 and S15 in FIG. 3).
2).

It is to be noted that the weight W of the test fluid measured through the weight sensor 33 may include the weight of the test fluid leaked before the presence or absence of the balance is confirmed in step S121. There is also. In such a case, the output of the weight sensor 33 is also monitored, and the output value when the balance is confirmed in the step S121 is subtracted from the value of the weight W.

After the flow rate Q per predetermined time is thus obtained, the flow rate Q is subjected to temperature correction based on the above equation (5) using the temperature correction value A previously obtained (step S160 in FIG. 2).

Then, the temperature-corrected flow rate Q and the previously measured generated pressure ΔP in the high-pressure chamber 14 are substituted into the above equation (3), and the value of the clearance h is obtained as the cube root thereof ( This is sampled as one of the inspection data (step S170 in FIG. 2). That is, it is stored in an appropriate memory (step S181 in FIG. 2).

After sampling one of the inspection data in this way, the relative angle between the cylinder 12 and the plunger 13 is changed to “90 °” through the drive unit 50 (step S110 in FIG. 2), and the above-described operation in FIG. Step S
Steps S120 to S181 are repeated. Thereafter, similarly, every time the inspection data is sampled, the relative angle between the cylinder 12 and the plunger 13 is sequentially changed to “180 °” and “270 °” through the drive unit 50, and the same processing is performed in steps S120 to S120. Step S181
Is repeated (step S182 in FIG. 2). Thereby, the value of the clearance h between the cylinder 12 and the plunger 13 can be obtained corresponding to each of the above-mentioned relative angles.

When the collection of all the inspection data is completed, finally, a judgment process for judging whether the clearance between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13 is appropriate is executed (step in FIG. 2). S190).

Hereinafter, the determination process will be described.
At the time of this determination, first, based on all the inspection data collected and collected, it is determined whether or not the data is within a predetermined range corresponding to the dimensional tolerance of the clearance. Then, when each of the data falls within the predetermined range, it is determined to be “suitable”, and when there is data that is out of the predetermined range, “No” is determined.
Is determined.

In this determination process, the cylinder 1
The deviation of the axis of the plunger 2 and the plunger 13 and the roundness of the radial section are also determined. That is, the values of the clearances h obtained corresponding to the respective relative angles between the cylinder 12 and the plunger 13 are not always the same, and usually, such deviation of the axis line, roundness of the radial cross section, etc. Varies depending on

Therefore, in the present embodiment, as the same determination processing, it is also determined whether or not each of the data falls within a predetermined range corresponding to an allowable value of the deviation of the axis and the roundness. If the data falls within the predetermined range, it is determined that "axis deviation and roundness are also appropriate". If there is data out of the predetermined range, "axis deviation" is determined. , The roundness is not ".

In this determination process, the monitor 4
2 may display only the above-described determination result, or may display the above-described inspection data and a line indicating the determination range thereof.

As described above, according to this embodiment, many excellent effects as listed below can be obtained. (1) The clearance between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13 is required without sending the test fluid into the fuel pump 10 or controlling the pressure of the sent test fluid. Thus, the suitability of the clearance can be determined more easily and accurately.

(2) In calculating the clearance, even if the flow rate of the test fluid passing through the clearance may change due to the temperature change of the test fluid,
The change in the flow rate is appropriately corrected according to the temperature change. For this reason, for the same clearance, the same determination result can be obtained regardless of a change in the temperature of the test fluid, and the determination accuracy is improved.

(3) By obtaining a plurality of data on the value of the clearance for each different relative angle between the cylinder 12 and the plunger 13, the cylinder 1
If the axes of the plunger 2 and the plunger 13 are displaced from each other, or if their radial cross sections are not perfectly circular, it is possible to determine whether or not the clearance is appropriate, including the actual state thereof.

In this embodiment, after the above equation (1) is balanced, the clearance h is calculated by measuring the generated pressure ΔP in the high-pressure chamber 14 and the flow rate Q of the test fluid. However, as shown in the equation (1), after the balance is obtained in this manner, ΔP = F / Ap (1) 'where Ap is also the cross-sectional area of the plunger 13 and the high-pressure chamber 14 Alternatively, the pressing load F of the plunger 13 may be measured instead of the generated pressure ΔP.

That is, as shown in FIG. 4, a part of the inspection procedure illustrated in FIG. 2 is changed and the above-mentioned balance is confirmed as the process of step S121. And measure.

The measured load F is converted into the generated pressure ΔP in the high-pressure chamber 14 based on the above equation (1) ′. (Steps S131 ′ and S132 ′ in FIG. 4)
May be performed instead of the processing in step S130 shown in FIG.

In this case, although a load meter (load sensor) for measuring the pressing load F is required, the disposition of the pressure sensor 32 becomes unnecessary. Also, in this case, the confirmation that the balance has been achieved is performed based on the fact that the output of the load sensor is monitored and the value converges to a constant value.

In the present embodiment, the weight W of the test fluid discharged from the fuel passage 17 corresponding to the clearance between the cylinder 12 and the plunger 13 is measured by the weight sensor 33, and this measurement is performed. Although the determined weight W is converted into the flow rate Q, an appropriate flow meter (flow rate sensor) may be used instead of the weight sensor 33. In this case, the value measured by the flow sensor can be used as it is as the flow value Q.

When the flow rate of the test fluid is measured as a weight, as in the embodiment, the beaker 3 is used.
As for the weight of the test fluid collected and stored in 3a,
By performing correction based on the evaporation coefficient, etc.,
This weight-related measurement error will be minimized. This is particularly effective when a highly volatile gasoline fuel itself is used as the test fluid.

In the present embodiment, the value of the clearance h itself is determined based on the above equation (3). However, in determining whether the clearance h is appropriate, the clearance h is not necessarily determined. There is no need to find the value itself. In short, it is sufficient that a value corresponding to the clearance is obtained as inspection data, and the measured values of the flow rate Q, the weight W, the generated pressure ΔP, the pressing load F, and the like are appropriately adopted as the inspection data. be able to.

(Second Embodiment) FIG. 5 shows a specific configuration of a fuel pump inspection apparatus according to a second embodiment of the present invention.

As shown in FIG. 5, the inspection apparatus of this embodiment eliminates the weight sensor 33 of the inspection apparatus of the first embodiment shown in FIG. Are newly provided with position sensors 34 and 35 for detecting the amount of movement.

That is, in the inspection apparatus of the embodiment, the computer 41 constituting the measurement and control unit 40
Is the plunger 13 by the position sensors 34 and 35
By detecting the passage of a specific position (for example, the chuck 54), the movement amount of the plunger 13 is measured, and the time required for the movement is measured. Then, the flow rate of the test fluid passing between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13 is calculated based on the measured movement amount and the required time.

For example, when the amount of movement of the plunger 13 is Δ
x (in this embodiment, it is also the interval between the position sensors 34 and 35), and the required time is Δt, the amount of compression ΔV in the high-pressure chamber 14 filled with the test fluid is ΔV = ApΔx (6) However, since Ap is the cross-sectional area of the plunger 13, the inner peripheral surface of the cylinder 12 and the plunger 1
The flow rate of the test fluid passing between the outer peripheral surface of No. 3 and Q is calculated as Q = ΔV / Δt (7).

As described above, the plunger 13 is inserted from the other end into the cylinder 12 filled with the test fluid in the closed space (high-pressure chamber 14) having one end sealed and pressed with an arbitrary load F. If you do, this plunger 1
The flow rate Q of the test fluid passing between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13 can also be obtained from the movement amount Δx and the time Δt required for the movement.

When the flow rate Q of the test fluid is obtained in this manner, thereafter, as in the first embodiment, the high-pressure chamber 1
The value of the clearance h between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13 is obtained by measuring the generated pressure ΔP in the cylinder 4 or the pressing load F of the plunger 13 based on the above equation (3). Will be able to do it.

FIG. 6 shows an example of an inspection procedure of the fuel pump performed by using such an inspection apparatus. Next, referring to FIG. 6, an inspection according to the embodiment will be described. The details of the inspection method of the fuel pump using the apparatus will be described.

Note that each processing shown in FIG. 6 is actually performed by the computer 4 constituting the measurement and control unit 40.
1 is performed. At the time of the inspection, first, the plunger 13 is inserted from the open end of the cylinder 12 in a state where the enlarged diameter portion 12 ′ of the cylinder 12 is filled with the test fluid, and then the cylinder 12 and the plunger 13 are Is set to “0 °” (see FIG. 6).
Step S210).

Thereafter, the plunger 13 is pressed with an arbitrary load F through the drive unit 50 (step S220 in FIG. 6). At this time, a specific position of the plunger 13 (for example, the chuck 54) through the position sensor 34.
Is detected first, and then, based on the detection of the passage of the plunger 13 at the same specific position through the position sensor 35, it is confirmed that the plunger 13 has moved by the movement amount Δx (step in FIG. 6). S230).
However, in the meantime, the high pressure chamber 14 is detected by the temperature sensor 31.
Measure the temperature of the test fluid inside.

The temperature correction value A of the test fluid is calculated based on the measured temperature value. (Steps S231 and S232 in FIG. 6) to prepare for a temperature correction described later.

The calculation of the temperature correction value A is performed based on the above equation (4). The calculation method is also optional, and the correction value A may be obtained by directly substituting the reference value and the measured value into the equation (4), or the trend of the correction value A corresponding to each measured value. May be obtained in advance as a map, and the correction value A may be obtained from each measurement value by map calculation including interpolation.

The temperature correction value A is obtained in this manner, and when the movement of the plunger 13 by Δx is confirmed, the time Δt required for the movement is measured (step S233 in FIG. 6). At the same time, based on the output of the pressure sensor 32,
Is measured (step S24 in FIG. 6).
0).

After that, based on the measured movement amount Δx and the required time Δt, the calculations of the above equations (6) and (7) are executed to determine the distance between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13. Is calculated (Step S250 in FIG. 6).

When the flow rate Q of the test fluid accompanying the movement of the plunger 13 is obtained in this manner, the temperature correction based on the above-mentioned equation (5) is also performed on the obtained flow rate Q by using the temperature correction value A previously obtained. (Step S260 in FIG. 6).

Then, the temperature-corrected flow rate Q and the previously measured generated pressure ΔP in the high-pressure chamber 14 are substituted into the above equation (3), and the value of the clearance h is calculated as the cube root thereof ( This is sampled as one piece of inspection data (step S270 in FIG. 6). That is, it is stored in an appropriate memory (step S281 in FIG. 6).

After sampling one of the inspection data in this way, the relative angle between the cylinder 12 and the plunger 13 is changed to “90 °” through the drive unit 50 (step S210 in FIG. 6), and the above-described operation in FIG. Step S
Steps S220 to S281 are repeated. Thereafter, similarly, every time the inspection data is sampled, the relative angle between the cylinder 12 and the plunger 13 is sequentially changed to “180 °” and “270 °” through the driving unit 50, and the same operations in steps S220 to S220 are performed. Step S281
(Step S282 in FIG. 6). Thereby, the value of the clearance h between the cylinder 12 and the plunger 13 can be obtained corresponding to each of the above-mentioned relative angles.

When the collection of all the inspection data is completed, finally, the judgment processing for judging whether the clearance between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13 is appropriate is performed in the first step. It is executed in the same manner as in the embodiment (step S290 in FIG. 6).

As described above, also according to this embodiment, it is possible to obtain many excellent effects listed below. (1) The clearance between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13 is required without sending the test fluid into the fuel pump 10 or controlling the pressure of the sent test fluid. Thus, the suitability of the clearance can be determined more easily and accurately.

(2) In calculating the clearance, the flow rate of the test fluid passing through the clearance due to a change in the temperature of the test fluid (in this case, precisely, the time Δt required for the plunger 13 to move by Δx) Is changed, the change in the flow rate is appropriately corrected according to the temperature change. For this reason, for the same clearance, the same determination result can be obtained regardless of a change in the temperature of the test fluid, and the determination accuracy is improved.

(3) By obtaining a plurality of data on the value of the clearance for each different relative angle between the cylinder 12 and the plunger 13, the cylinder 1
If the axes of the plunger 2 and the plunger 13 are displaced from each other, or if their radial cross sections are not perfectly circular, it is possible to determine whether or not the clearance is appropriate, including the actual state thereof.

(4) Since it is not necessary to directly measure the flow rate of the test fluid and to dispose a weight sensor or the like, the inspection procedure itself is simplified and the inspection apparatus is further simplified. Is achieved.

In this embodiment, the clearance h is calculated by measuring the generated pressure ΔP in the high-pressure chamber 14.
Instead of P, the pressing load F of the plunger 13 may be measured, and this pressing load F may be converted into the generated pressure ΔP in the high-pressure chamber 14 based on the relationship of the above-mentioned equation (1) ′. That is, instead of the processing in step S240 shown in FIG. 6, steps S131 ′ and S13 shown in FIG.
The processing of 2 ′ may be executed. Also in this case, although a load meter (load sensor) for measuring the pressing load F is required, the disposition of the pressure sensor 32 is unnecessary.

Also, in the present embodiment, the value of the clearance h itself is determined based on the equation (3). However, in determining whether the clearance h is appropriate, the clearance h is not necessarily determined. There is no need to find the value itself. In this case, what is essential is that the value corresponding to the clearance is obtained as the inspection data, and the calculated value of the flow rate Q and the measured values of the generated pressure ΔP and the pressing load F are appropriately used as the inspection data. Can be adopted.

In the present embodiment, the movement of the plunger 13 is measured through the position sensors 34 and 35. However, the movement of the movement actuator 52 is fed back to the computer 41.
If the movement amount of the plunger 13 can be recognized by another method, the arrangement of the position sensors 34 and 35 can be omitted.

(Third Embodiment) FIG. 7 shows a specific configuration of a fuel pump inspection apparatus according to a third embodiment of the present invention.

In the third embodiment, unlike the first and second embodiments, the cylinder 12 formed on the pump main body 11 of the fuel pump 10 and having the inner peripheral surface coated with the test fluid is different from the first embodiment. Is open at one end, and the plunger 13 is inserted from the other end and pressed with a constant load. Based on the moving speed of the plunger 13 at that time, the distance between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13 is increased. The clearance is determined and its suitability is determined.

That is, as shown in FIG. 7, in the inspection apparatus of this embodiment, the other end of the pump body 11 into which the plunger 13 is inserted is opened as the fuel pump 10 to be inspected. That is, the fuel passage 18 that is not sealed by the jig and the second fuel passage serving as the output passage from the pump chamber is left as it is as the fuel passage 18 is used. For this reason, the space 14 ′ (corresponding to the pump chamber) formed in the enlarged diameter portion 12 ′ of the cylinder 12 does not become a high-pressure chamber during the inspection, and the pressure sensor 32 ( 1 and 5) are omitted.

In this embodiment, it is not necessary that the space 14 'is filled with the test fluid. That is, in this embodiment, the test fluid is the cylinder 1
2 may be appropriately applied to the inner peripheral surface of the cylinder 12 and may be interposed between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13 as a so-called oil film.

In the inspection apparatus of this embodiment,
Position sensors 34 and 35 are used as a device for determining the moving speed of the plunger 13. Other configurations of the inspection apparatus are substantially similar to those of the inspection apparatus of the second embodiment illustrated in FIG.

As described above, in the fuel pump 10 in which the test fluid is applied to the inner peripheral surface of the cylinder 12, the cylinder 1
The test fluid interposed between 2 and plunger 13 includes:
A shearing force acts upon insertion and pressing of the plunger 13. This shearing force is substantially proportional to the ratio between the insertion speed (movement speed) of the plunger 13 and the film thickness (oil film thickness) of the test fluid.

That is, the sliding area of the plunger 13 is Z
(= ΠdL), when the moving speed of the plunger 13 is v, the oil film thickness of the test fluid is h, and the viscosity coefficient (fluid viscosity) of the test fluid is μ, the shear force is Fs, Fs = Zμ (dv / dh) (8)

Thus, the oil film thickness h of the test fluid is considered as a clearance between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13, and the shearing force Fs is considered as the constant pressing load of the plunger 13. For example, by measuring the moving speed v of the plunger 13, the clearance (oil film thickness) h can be obtained.

However, also in the above equation (8), the fluid viscosity μ is a value that changes according to the temperature of the same fluid (test fluid). Actually, μ (measured temperature) / μ (reference temperature) = A ′ (9) The shear force Fs, and thus the clearance (oil film thickness) h, also changes by the ratio A ′.

Therefore, in this embodiment, the value of the clearance (oil film thickness) h is subjected to temperature correction in the form of h ← h · A ′ (10).

The suitability of the temperature-corrected clearance (oil film thickness) h is determined based on the value of the clearance h. The calculation of the clearance h at a plurality of positions corresponding to the different relative angles of the cylinder 12 and the plunger 13 displaced through the drive unit 50 is the same in the present embodiment.

FIG. 8 shows an example of an inspection procedure of a fuel pump executed by using such an inspection apparatus. Next, referring to FIG. 8, an inspection according to the embodiment will be described. The details of the inspection method of the fuel pump using the apparatus will be described.

Note that each processing shown in FIG. 8 is actually performed by the computer 4 constituting the measurement and control unit 40.
1 is performed. At the time of the inspection, first, the plunger 13 is inserted from the open end of the cylinder 12 on which the test fluid is applied to the inner peripheral surface as described above, and then the driving unit 50 is driven.
, The relative angle between the cylinder 12 and the plunger 13 is set to “0 °” (step S31 in FIG. 8).
0).

Thereafter, the plunger 13 is pressed with a constant load Fs through the drive unit 50 (step S320 in FIG. 8). At this time, a specific position of the plunger 13 (for example,
4) is first detected, and then the position sensor 3
It is confirmed that the plunger 13 has moved by Δx based on the detection of the passage of the plunger 13 through the same specific position through 5 (step S330 in FIG. 8). In the meantime, the temperature of the test fluid (oil film temperature) is measured by the temperature sensor 31.

The temperature correction value A 'is calculated based on the measured temperature value. (Step S331 in FIG. 8)
And S332) to prepare for temperature correction described later. The calculation of the temperature correction value A ′ is performed based on the above equation (9), but such an operation method is optional as described above.

The temperature correction value A 'is obtained in this manner, and when the movement of the plunger 13 by Δx is confirmed, the time Δt required for the movement is measured (step S333 in FIG. 8), and the calculation v = Δx / Δt (FIG. 8) 11) to calculate the moving speed v of the plunger 13 (step S340 in FIG. 8).

After the moving speed v of the plunger 13 is obtained in this manner, the known pressing load (constant load) Fs of the plunger 13 and the obtained plunger 13
Is substituted into the above equation (8), and the cylinder 1
The clearance h between the plunger 2 and the plunger 13 (the oil film thickness of the test fluid) is calculated (step S35 in FIG. 8).
0).

Thereafter, the obtained clearance (oil film thickness) h is subjected to temperature correction based on the above equation (10) (step S360 in FIG. 8), and the temperature corrected clearance (oil film thickness) h is determined. The value is sampled as one of the inspection data. That is, it is stored in an appropriate memory (step S371 in FIG. 8).

After sampling one of the inspection data in this way, the relative angle between the cylinder 12 and the plunger 13 is changed to “90 °” through the driving unit 50 (step S310 in FIG. 8), and the above-described operation in FIG. Step S
The processing from 320 to step S371 is repeated. Thereafter, similarly, every time the inspection data is sampled, the relative angle between the cylinder 12 and the plunger 13 is sequentially changed to “180 °” and “270 °” through the driving unit 50, and the same processing is performed in steps S320 to S320. Step S371
(Step S372 in FIG. 8). Thereby, the value of the clearance (oil film thickness) h between the cylinder 12 and the plunger 13 can be obtained corresponding to each of the relative angles described above.

When the collection of all the inspection data is completed, finally, the judgment processing for judging whether or not the clearance between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13 is appropriate is performed in the first or the first step. It is executed in the same manner as in the second embodiment (step S380 in FIG. 7).

As described above, also according to this embodiment, it is possible to obtain many excellent effects as listed below. (1) The clearance between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13 is required without sending the test fluid into the fuel pump 10 or controlling the pressure of the sent test fluid. Thus, the suitability of the clearance can be determined more easily and accurately.

(2) In calculating the clearance, the shear force F due to the temperature change of the test fluid (oil film) was calculated.
Even if the value of s and, consequently, the value of the clearance may change, the change of the value is appropriately corrected according to the temperature change. For this reason, for the same clearance, the same determination result can be obtained regardless of the temperature change of the test fluid (oil film), and the determination accuracy is improved.

(3) By obtaining a plurality of data on the value of the clearance for each different relative angle between the cylinder 12 and the plunger 13, the cylinder 1
If the axes of the plunger 2 and the plunger 13 are displaced from each other, or if their radial cross sections are not perfectly circular, it is possible to determine whether or not the clearance is appropriate, including the actual state thereof.

(4) It is not necessary to measure the flow rate and pressure of the test fluid, and it is not necessary to dispose a weight sensor, a pressure sensor, and the like. Further simplification is achieved.

In the present embodiment, the moving speed of the plunger 13 is measured through the position sensors 34 and 35.
If the moving speed of the plunger 13 can be recognized by another method, such as when the moving speed of the plunger 13 is fed back to the computer 41, the arrangement of the position sensors 34 and 35 can be omitted.

Further, in this embodiment, the cylinder 12 having one end open and the test fluid applied to the inner peripheral surface is provided.
The plunger 13 is inserted from the other end and pressed with a constant load Fs, and the clearance between the inner peripheral surface of the cylinder 12 and the outer peripheral surface of the plunger 13 is determined based on the moving speed v of the plunger 13 at that time. However, according to the above equation (8), the clearance h as the oil film thickness can also be calculated by keeping the moving speed v of the plunger 13 constant and measuring the pressing load Fs of the plunger at that time.

That is, in this case, the arrangement of the position sensors 34 and 35 is omitted, an appropriate load meter (load sensor) is provided in the drive unit 50, and the inspection is performed according to the procedure illustrated in FIG. Become.

In the procedure illustrated in FIG.
Processing related to step S410 and step S470
The processing according to steps S490 to S490 includes the processing according to step S310 of the procedure illustrated in FIG.
Steps S to S380 are the same as steps S to S380.
The processing relating to 420 to S460, ie, the plunger 13 is pressed at a constant speed v.

In this state, the temperature (oil film temperature) of the test fluid is measured by the temperature sensor 31. The temperature correction value A ′ based on the measured temperature value;
Is calculated.

The pressing load Fs of the pressing plunger 13 is measured by a separately provided load meter (load sensor). After measuring the pressing load Fs of the plunger 13 in this way, the known moving speed v of the plunger 13 and the measured pressing load Fs are substituted into the above equation (8), and the relationship between the cylinder 12 and the plunger 13 is determined. The clearance h (film thickness of the test fluid oil) between them is calculated. Is different from the procedure illustrated in FIG.

Even when the clearance (oil film thickness) h is obtained in such an embodiment and procedure, as a result, the same effects as the effects (1) to (4) of the above embodiment are obtained. The effect can be obtained.

In each case, the above (8)
Although the value of the clearance (oil film thickness) h is determined based on the equation, it is not always necessary to determine the value of the clearance (oil film thickness) h in determining whether the clearance is appropriate. In this case, what is essential is that the value corresponding to the clearance is obtained as the inspection data, and the calculated moving speed v, the measured pressing load Fs, and the like are appropriately adopted as the inspection data. Can be.

In addition, the fuel pump inspection method and the inspection apparatus according to the present invention are not limited to the above-described embodiments, and the embodiments may be modified as appropriate, for example, as follows. Can also.

In each of the above embodiments, the deep portion corresponding to the high-pressure chamber 14 or the space 14 'of the cylinder 12 is the enlarged diameter portion 12', and the tip of the plunger 13 is formed as shown in FIGS. Alternatively, in the mode shown in FIG.
The case where the present invention is applied to a fuel pump in which the actual sliding length L or sliding area Z (= πdL) of the plunger 13 is constant as long as it protrudes to 2 ′ has been described. Such an inspection method and an inspection apparatus can be similarly applied to a fuel pump in which the cylinder 12 is not provided with such an enlarged diameter portion 12 ′. That is, in this case, the driving amount (movement amount) of the driving unit 50 is appropriately monitored through the computer 41, and the sliding length L at that time is reflected in the above-mentioned expressions (3) and (8). I just need.

In each of the above embodiments, the test fluid supplied from the high-pressure generating section 20 is a liquid such as CCF (carburetor control fluid) having a property similar to gasoline fuel. The test fluid is optional. Alternatively, for example, silicon oil or gasoline fuel itself may be used as the test fluid.

In the above embodiments, the temperature of the test fluid is detected, and the flow rate and oil film thickness (clearance) of the test fluid are corrected based on the detected temperatures. If the influence of the temperature, such as the flow rate and the oil film thickness, can be neglected, such temperature correction may be omitted.

In the above embodiments, the driving unit 5
0 while displacing the relative angle between the cylinder 12 and the plunger 13 of the fuel pump 10
Although a plurality of inspection data corresponding to different relative angles between the plunger and the plunger 13 are collected, this is also arbitrary, and it is not always necessary to perform such displacement of the relative angle. That is, even if the same inspection is performed only at a specific relative angle between the cylinder 12 and the plunger 13, effects other than the effect (3) can be obtained.

Also, the setting contents relating to the displacement of the relative angle, ie, “0 °”, “90 °”, “180 °”,
A value such as “270 °” is also arbitrary. Regardless of the displacement of the relative angles, any value can be set according to the purpose of the inspection.

The type and the like of the fuel pump to be inspected by the inspection method and the inspection apparatus according to the present invention are also arbitrary. In short, the inspection method and the inspection apparatus according to the present invention can be applied to a pump in which a cylinder is formed in a pump body and a plunger slides in the cylinder to pressurize and discharge fuel.

[0185]

According to the present invention, the test fluid is supplied between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger without sending the test fluid into the fuel pump or controlling the pressure of the supplied test fluid. The clearance is required, and the suitability of the clearance can be determined more easily and accurately.

In particular, claims 2, 4, 7, 9, 13,
In the invention described in Item 17, by performing the calculation of the clearance at a plurality of positions corresponding to the different relative angles of the cylinder and the plunger, the accuracy of the determination is further improved.

By the way, if a plurality of data on the clearance is obtained at different relative angles between the cylinder and the plunger, that is, at different relative positions with respect to the rotational direction of the cylinder and the plunger, the axes of the cylinder and the plunger are mutually aligned. Even in the case where the clearances are shifted or the radial cross sections of both of them are not perfect circles, it is possible to determine whether the clearance is appropriate or not, including the actual state thereof.

In particular, in the inventions according to the fifth, tenth, fourteenth, and eighteenth aspects, since the temperature of each inspection data is corrected, the reliability of the inspection data is improved, and furthermore, the appropriateness of the clearance is determined. The judgment accuracy can be improved.

According to the eleventh aspect, the inspection method according to the first aspect is provided. According to the twelfth aspect, the inspection method according to the third aspect is provided. According to the invention described in Item 13, the inspection method according to the inventions described in Claims 2 and 4 is provided. According to the invention described in Item 14, the inspection method according to the invention described in Claim 5 is provided according to the invention described in Claim 15. According to the invention, an inspection method according to the invention of claim 6 is provided.
According to the inspection method according to the invention described in claim 17, according to the invention described in claim 17, the inspection method according to the invention in claims 7 and 9 is applied to the invention described in claim 10, according to the invention described in claim 18. Such an inspection method can also be executed accurately.

[Brief description of the drawings]

FIG. 1 is a first view of a fuel pump inspection apparatus according to the present invention.
FIG. 2 is a block diagram showing a device configuration of the embodiment.

FIG. 2 is a flowchart showing an example of an inspection procedure performed using the inspection apparatus.

FIG. 3 is a flowchart showing an example of an inspection procedure performed using the inspection apparatus.

FIG. 4 is a flowchart showing a part of another example of the inspection procedure.

FIG. 5 shows a second embodiment of the fuel pump inspection apparatus according to the present invention.
FIG. 2 is a block diagram showing a device configuration of the embodiment.

FIG. 6 is a flowchart showing an example of an inspection procedure executed using the inspection apparatus.

FIG. 7 is a third view of the fuel pump inspection apparatus according to the present invention.
FIG. 2 is a block diagram showing a device configuration of the embodiment.

FIG. 8 is a flowchart showing an example of an inspection procedure performed using the inspection apparatus.

FIG. 9 is a flowchart showing another example of the inspection procedure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Fuel pump, 11 ... Pump body, 12 ... Cylinder, 12 '... Expanding part, 13 ... Plunger, 14 ... High pressure chamber, 14' ... Space, 15 ... Annular groove, 16 ... Low pressure chamber, 1
7, 18: fuel passage, 30: detecting unit, 31: temperature sensor, 32: pressure sensor, 33: weight sensor (electronic balance), 33a: beaker, 34, 35: position sensor, 40
... Measurement and control unit, 41 ... Computer, 42 ... Monitor (display), 50 ... Drive unit, 51 ... Rail, 52
... moving actuator, 53 ... rotating actuator, 53a ... rotary shaft, 54 ... chuck.

 ────────────────────────────────────────────────── ─── Continued from the front page (72) Inventor Yasuhiro Yamamoto 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (reference) 2G067 AA21 DD02 DD04 2G087 AA19 BB01 CC11 CC28 CC31 DD03

Claims (18)

[Claims] 1. A test fluid is filled by sealing one end of a cylinder formed in a pump body of a fuel pump.
The plunger is inserted from the other end and pressed by an arbitrary load, and when the pressure of the space filled with the test fluid and the pressing load of the plunger are balanced, the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger. And determining a clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the flow rate of the test fluid passing therethrough and the balanced pressure or load to determine whether or not the clearance is appropriate. Fuel pump inspection method. 2. A test fluid is filled by sealing one end of a cylinder formed in a pump body of the fuel pump, and
The plunger is inserted from the other end and pressed with an arbitrary load, and when the pressure of the space filled with the test fluid and the pressing load of the plunger are balanced, the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger. Determining the clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the flow rate of the test fluid passing between the cylinder and the plunger based on the balanced pressure or load. An inspection method for a fuel pump, wherein the inspection is performed a plurality of times corresponding to different relative angles, and the propriety is determined based on the plurality of clearance values obtained. 3. A test fluid is filled by sealing one end of a cylinder formed in a pump body of the fuel pump, and
A test in which the plunger is inserted from the other end and pressed with an arbitrary load, and passes between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the amount of movement of the plunger and the time required for the movement. The flow rate of the fluid is determined, and the clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger is determined based on the determined flow rate and the pressure of the space filled with the test fluid or the pressing load of the plunger. A fuel pump inspection method for determining whether or not the fuel pump is appropriate. 4. A test fluid is filled by sealing one end of a cylinder formed in a pump body of the fuel pump,
A test in which the plunger is inserted from the other end and pressed with an arbitrary load, and passes between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the amount of movement of the plunger and the time required for the movement. The flow rate of the fluid is determined, and the clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger is determined based on the determined flow rate and the pressure of the space filled with the test fluid or the pressing load of the plunger. A method for inspecting a fuel pump, wherein the step is performed a plurality of times corresponding to different relative angles of the cylinder and the plunger, and the propriety is determined based on the plurality of clearance values obtained. 5. The fuel pump inspection method according to claim 1, wherein a temperature of the test fluid is detected, and a flow value of the test fluid used for calculating the clearance is detected. An inspection method for a fuel pump, wherein the inspection is performed based on a temperature value. 6. One end of a cylinder formed on a pump body of a fuel pump and having a test fluid applied to an inner peripheral surface thereof is opened, and a plunger is inserted from the other end and pressed with a constant load. A method for determining the suitability of a clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the moving speed of the plunger. 7. One end of a cylinder formed on a pump body of a fuel pump and having a test fluid applied to an inner peripheral surface thereof is opened, and a plunger is inserted from the other end and pressed with a constant load. The step of obtaining a clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the moving speed of the plunger is performed a plurality of times corresponding to each different relative angle between the cylinder and the plunger. An inspection method for a fuel pump, comprising: judging suitability based on a plurality of clearance values. 8. One end of a cylinder formed on a pump body of a fuel pump and having a test fluid applied to an inner peripheral surface thereof is opened, and a plunger is inserted from the other end and pressed at a constant speed. A method for determining a clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the pressing load of the plunger and determining whether the clearance is appropriate or not. 9. One end of a cylinder formed on a pump body of a fuel pump and having a test fluid applied to an inner peripheral surface thereof is opened, and a plunger is inserted from the other end and pressed at a constant speed. The step of obtaining the clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the pressing load of the plunger is performed a plurality of times corresponding to each different relative angle between the cylinder and the plunger, and the obtained values are obtained. An inspection method for a fuel pump, comprising: judging suitability based on a plurality of clearance values. 10. The fuel pump inspection method according to claim 6, wherein the temperature of the test fluid is detected, and the value of the clearance determined is corrected based on the detected temperature value. Characteristic fuel pump inspection method. 11. A means for inserting a plunger with an arbitrary load from the other end into a cylinder of a fuel pump filled at one end with a test fluid, the inner peripheral surface of the cylinder of the fuel pump and the outer peripheral surface of the plunger. A means for measuring a flow rate of the test fluid passing between the test fluid; a means for measuring one of a pressure of a space filled with the test fluid and a pressing load of the plunger; and Means for calculating a clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the flow rate and the pressure of the space filled with the test fluid or the pressing load of the plunger; Means for determining the suitability of the clearance based on the value. 12. A means for inserting a plunger with an arbitrary load from the other end into a cylinder of a fuel pump filled with a test fluid with one end sealed, a means for measuring the amount of movement of the plunger, Means for measuring the time required for the movement, and calculating the flow rate of the test fluid passing between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the measured movement amount of the plunger and the required time. Means for measuring any one of the pressure of the space filled with the test fluid and the pressing load of the plunger; and the pressure of the space filled with the test fluid to be measured or the pressing load of the plunger, and Means for calculating a clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the calculated flow rate of the test fluid; Inspection device for a fuel pump, characterized in that based on the value of the clearance is calculated and a means for determining the appropriateness of the clearance. 13. The fuel pump inspection apparatus according to claim 11, further comprising: means for displacing a relative angle between the cylinder and the plunger of the fuel pump, wherein the means for calculating the clearance comprises the cylinder. And calculating a plurality of values of the clearance corresponding to the plurality of relative angles displaced with the plunger. The means for determining whether the clearance is appropriate is based on the calculated values of the plurality of clearances. A fuel pump inspection device for determining whether the clearance is appropriate. 14. The fuel pump inspection device according to claim 11, further comprising: means for detecting a temperature of the test fluid, wherein the means for calculating the clearance is used for calculating the clearance. A fuel pump inspection method, wherein the clearance is calculated by correcting a flow rate value of a test fluid to be obtained based on the detected temperature value. 15. A means for inserting a plunger with a constant load from the other end into a cylinder of a fuel pump having one end opened and a test fluid applied to an inner peripheral surface thereof, and measuring a moving speed of the inserted plunger. Means for calculating the clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the measured moving speed of the plunger and the constant insertion load; and Means for determining the suitability of the clearance based on the value. 16. A means for inserting a plunger from the other end at a constant speed into a cylinder of a fuel pump having one end opened and a test fluid applied to an inner peripheral surface thereof, and measuring a pressing load of the inserted plunger. Means for calculating the clearance between the inner peripheral surface of the cylinder and the outer peripheral surface of the plunger based on the measured pressing load of the plunger and the constant insertion speed; and Means for determining the suitability of the clearance based on the value. 17. The fuel pump inspection device according to claim 15, further comprising: means for displacing a relative angle between the cylinder and the plunger of the fuel pump, wherein the means for calculating the clearance comprises the cylinder. And calculating a plurality of values of the clearance corresponding to the plurality of relative angles displaced with the plunger. The means for determining whether the clearance is appropriate is based on the calculated values of the plurality of clearances. A fuel pump inspection device for determining whether the clearance is appropriate. 18. The fuel pump inspection device according to claim 15, further comprising: means for detecting a temperature of the test fluid, wherein the means for calculating the clearance comprises a value of the calculated clearance. Is calculated as a value corrected based on the detected temperature value.