JPH05231804A - Method and instrument for measuring circularity - Google Patents

Abstract

PURPOSE:To shorten the measuring time of the instrument by improving the measuring efficiency of the instrument and, at the same time, to further improve the measurement accuracy of the instrument. CONSTITUTION:A measuring section 48A which can be brought into contact with the inner periphery of an opened hole 50A is provided on the outer periphery of a probe 48 and, at the same time, another measuring section 48B which can be brought into contact with the inner periphery of a jet 50B is provided at the front end of the probe 48. Then the distance between the contact point of the sections 48A and that of the section 48B is set smaller than the distance L2 between the inner periphery of the hole 50a and that of the jet 50B. Accordingly, when the section 48A is moved toward the jet 50B while the section 48A is brought into contact with the inner periphery of the hole 50A, the section 48B is brought into contact with the inner periphery of the jet 50B and the section 49A is separated from the inner periphery of the hole 50A. Therefore, the section 48B can measure the axis of the jet 50B continuously from the axis of the hole 50A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roundness measuring method and apparatus, and more particularly to a roundness measuring method and apparatus for determining the coaxiality of each opening formed coaxially in an object to be measured.

[0002]

2. Description of the Related Art FIG. 5 shows a fuel injection nozzle used in an automobile or the like. An injection port 12 of the fuel injection nozzle 10 supplies atomized fuel to an engine (not shown). Is set to a small diameter. The injection port 12 needs to be formed at the tip of the cylindrical fuel injection nozzle 10 coaxially with the opening hole 14 of the cylindrical portion.

A roundness measuring machine is used to inspect whether the injection port 12 and the opening hole 14 of the produced product are coaxially formed.

[0004]

However, the injection port 12 of the fuel injection nozzle 10 is formed with a small diameter,
Further, since it is located at the tip of the opening hole 14, the injection port 12 cannot be seen when viewed from the side A of the opening hole 14. Therefore,
After measuring the axis of the opening hole 14 with the probe of the roundness measuring machine, the probe cannot be set on the inner circumference of the injection port 12 from the side of the opening hole 14, so the axis of the injection port 12 is measured. In this case, it is necessary to turn the fuel injection nozzle 10 upside down and position the injection port 12 upward.

Therefore, first, the fuel injection nozzle 10 is fixed at the measurement position with the injection port 12 positioned downward, and the axial center of the opening hole 14 is measured, and then the axial center of the outer periphery of the fuel injection nozzle 10 is measured. taking measurement. Next, the fuel injection nozzle 10 is fixed at the measurement position while the fuel injection nozzle 10 is turned upside down and the injection port 12 is positioned above.
Of the fuel injection nozzle 10 is further measured.

Then, when the injection port 12 is positioned downward and when the injection port 12 is positioned upward, the axial center of the outer circumference of each fuel injection nozzle 10 is used as a medium, and the concentricity of the opening hole 14 and the injection port 12 is concentric. Ask for degrees. Therefore, it is necessary to set the fuel injection nozzle 10 to the measurement position twice with the top and bottom reversed, and further it is necessary to measure the axial center of the outer periphery of the fuel injection nozzle 10 twice in each state. There is a problem that the measurement efficiency is poor and a measurement error is likely to occur.

The present invention has been made in view of the above circumstances, and a roundness that can shorten the measurement time by improving the measurement efficiency and further improve the measurement accuracy. It is an object of the present invention to provide a measuring method and device.

[0008]

In order to achieve the above object, the present invention provides a first opening hole coaxially formed in an object to be measured, and a first opening hole formed at the bottom of the first opening hole. In a roundness measuring device provided with a measuring element for determining a concentricity with a second opening having a diameter smaller than that of the opening, a first measuring part capable of contacting the inner circumference of the first opening is provided on the outer circumference of the measuring tip. A second measuring unit that is provided and is in contact with the inner circumference of the second opening hole is provided at the tip of the probe, and the distance between the contact point of the first measuring unit and the contact point of the second measuring unit is set to the first measuring unit. The distance is set smaller than the distance between the inner circumference of the opening hole and the inner circumference of the second opening hole, and the first measuring unit is moved toward the second opening hole while being in contact with the inner circumference of the first opening hole. A second measuring portion is brought into contact with the inner circumference of the second opening hole, and the first measuring portion is separated from the inner circumference of the first opening hole. That.

[0009]

According to the present invention, the first measuring portion which can contact the inner circumference of the first opening hole is provided on the outer circumference of the measuring element, and the tip of the measuring element can contact the inner circumference of the second opening hole. A measuring unit was provided. Then, the distance between the contact point of the first measurement section and the contact point of the second measurement section was set smaller than the distance between the inner circumference of the first opening hole and the inner circumference of the second opening hole. Therefore, when the first measuring unit is moved in the direction of the second opening hole while being in contact with the inner circumference of the first opening hole, the second measuring unit is in contact with the inner circumference of the second opening hole and the first measuring unit is also in contact. Separate from the inner circumference of the first opening hole.

Thus, the second measuring section can measure the axial center of the second opening hole while continuing the axial center of the first opening hole.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A roundness measuring method and apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a side view of a roundness measuring device according to the present invention. A table 34 is rotatably provided on the main body 32 of the roundness measuring device 30, and the table 34 is rotated by driving a motor (not shown). The table 34 has an X-axis knob 36 and a Y-axis.
A shaft knob 38 is provided, and the table 34 moves in the X-axis direction when the X-axis knob 36 is operated, and moves in the Y-axis direction when the Y-axis knob 38 is operated.

Further, a column 40 is erected on the table 34, and an up-and-down table 42 which is vertically movable along the column 40 is supported on the column 40. An arm 44 is supported on the upper and lower pedestals 42, and a probe 48 is provided on the arm 44 via a detector 46. Then, the work piece 50 in which the tracing stylus 48 is placed on the table 34
The table 34 is rotated in a state of being in contact with, and the shaft center and the like are measured.

FIG. 2 shows an enlarged view of the main part of the roundness measuring device according to the present invention. As shown in FIG.
A measuring portion 48A is fixed to the outer circumference of the tip of the measuring element 48 attached to the measuring element 48, and a measuring portion 48C is fixed to the tip of the measuring element 48 via a shaft 48B.
As shown in FIG. 4, the distance L1 from the tip of the measurement unit 48A to the right end of the measurement unit 48C is from the inner periphery of the opening hole 50A formed in the fuel injection nozzle 50 to the injection port 5.
It is set to be slightly smaller than the distance L2 to the inner circumference of 0B.

Therefore, as shown in FIG. 3, the probe 48 is moved downward along the inner circumference of the opening hole 50A while the measuring portion 48A is in contact with the inner circumference of the opening hole 50A of the fuel injection nozzle 50. Then, the measuring unit 48C is guided into the ejection port 50B. Then, when the tracing stylus 48 is moved further downward from the state where the measuring unit 48C is guided inside the ejection port 50B, the measuring unit 48C comes into contact with the inner circumference of the ejection port 50B. In this case, the distance L1 from the tip of the measurement unit 48A to the right end of the measurement unit 48C is smaller than the distance L2 from the inner circumference of the opening hole 50A formed in the fuel injection nozzle 50 to the inner circumference of the injection port 50B. Since it is set to be small, the contact point 48 is slightly bent, and the contact between the measuring portion 48A and the inner circumference of the opening hole 50A is released (see FIG. 4).

The operation of the roundness measuring device according to the present invention thus constructed will be described. First, the fuel injection nozzle 50 is arranged with the injection port 50B downward, and the opening hole 50A is held on the table 34 in a vertical state. In this state, the tracing stylus 48 is fitted in the opening hole 50A, and the measuring unit 4
8A is brought into contact with the inner circumference of the opening hole 50A. Next, the table 34 is rotated to measure the axis of the opening hole 50A.

Next, when the measuring section 48A is moved downward with the measuring section 48A in contact with the inner periphery of the opening hole 50A, the measuring section 48C is guided into the injection port 50B (FIG. 3).
reference). Further, when the tracing stylus 48 is moved downward, the measuring portion 48C comes into contact with the inner circumference of the injection port 50B, and the measuring portion 4C
The contact between 8A and the inner periphery of the opening hole 50A is released (FIG. 4).
reference). In this state, the table 34 is rotated to rotate the injection port 50.
Measure the B axis.

The axis of the opening 50A and the injection port 50
The concentricity of the opening hole 50A and the injection port 50B is determined from the axis of B. In this way, the measuring unit 4 is attached to the outer circumference of the tip of the probe 48.
8A is fixed and the measuring unit 48 is attached to the tip of the probe 48.
By fixing C, the fuel injection nozzle 50 can be used as the injection port 50B as a guide. Therefore,
Since the measuring portion 48C can be inserted into the ejection port 50B which is formed at the bottom of the ejection port 50B and is difficult to see,
It is no longer necessary to reverse the fuel injection nozzle 50 and position the injection port 50B upward.

In the above embodiment, the case where the concentricity between the opening hole 50A of the fuel injection nozzle 50 and the injection port 50B is obtained has been described. It can also be applied to other formed DUTs.

[0019]

As described above, according to the roundness measuring method and apparatus according to the present invention, the first measuring portion is moved in the direction of the second opening hole while being in contact with the inner circumference of the first opening hole. Then, the second measuring portion contacts the inner circumference of the second opening hole, and the first measuring portion moves away from the inner circumference of the first opening hole. This allows
The second measuring section can be continuous with the axis of the first opening to measure the axis of the second opening.

Therefore, by improving the measurement efficiency, the measurement time can be shortened and the measurement accuracy can be further improved.

[Brief description of drawings]

FIG. 1 is a side view of a roundness measuring device according to the present invention.

FIG. 2 is an enlarged view of a main part of the roundness measuring device according to the present invention.

FIG. 3 is a diagram for explaining a state in which a probe of a roundness measuring device according to the present invention measures an opening hole of a fuel injection nozzle.

FIG. 4 is a cross-sectional view illustrating a state in which a probe of a roundness measuring device according to the present invention measures an injection port of a fuel injection nozzle.

FIG. 5 is a sectional view of a fuel injection nozzle measured by a roundness measuring device according to the present invention.

[Explanation of symbols]

 30 ... Roundness measuring device 48 ... Measuring element 48A, 48B ... Measuring part 50 ... Fuel injection nozzle 50A ... Opening hole 50B ... Injection port L1 ... Distance between measuring parts 48A and 48B L2 ... Respectively of opening hole and injection port Distance between inner circumference

Claims (2)

[Claims] 1. A measurement for obtaining a concentricity between a first opening hole coaxially formed in an object to be measured and a second opening hole formed at a bottom portion of the first opening hole and having a diameter smaller than that of the first opening hole. In the roundness measuring method with a probe, the first measuring unit provided on the outer circumference of the probe is provided with the first measuring unit.
The axial center of the first opening hole is measured by contacting the inner circumference of the opening hole, and the first tip portion is moved in the direction of the second opening hole while being in contact with the inner circumference of the first opening hole. A second measuring part provided at the tip of the probe is brought into contact with the inner circumference of the second opening hole, and the first measuring part is separated from the inner circumference of the first opening hole; A method of measuring the axial center of the two opening holes and determining the concentricity of the first opening hole and the second opening hole from the respective axial centers of the first opening hole and the second opening hole. 2. A measurement for determining the concentricity between a first opening hole formed coaxially on the object to be measured and a second opening hole formed at the bottom of the first opening hole and having a diameter smaller than that of the first opening hole. In a roundness measuring device including a probe, a first measuring unit capable of contacting an inner circumference of the first opening hole is provided on an outer circumference of the probe and the second measuring unit is provided at a tip of the probe.
A second measuring unit that can contact the inner circumference of the opening hole is provided, and the distance between the contact point of the first measuring unit and the contact point of the second measuring unit is set to the inner circumference of the first opening hole and the second opening hole. The distance between the inner circumferences is set to be smaller, and the first measuring portion is moved toward the second opening hole while being in contact with the inner circumference of the first opening hole to move the second measuring portion to the second opening hole. Circularity measuring device, wherein the first measuring portion is separated from the inner periphery of the first opening hole while being in contact with the inner periphery of the.