JP7697698B2 - Air micrometer measuring head and air micrometer equipped with said measuring head - Google Patents

Description

The present invention relates to a measuring head for an air micrometer and an air micrometer equipped with the measuring head. In particular, the present invention relates to improvements to the measuring head in accordance with the shape of the object to be measured.

Conventionally, air micrometers such as those disclosed in Patent Document 1 and Patent Document 2 are known. In this air micrometer, compressed air controlled to a constant pressure is blown out of an air outlet in a measuring head, and when a measurement object is placed in front of this air outlet, the amount of air blown out and the back pressure change depending on the distance between the air outlet and the measurement object. This is utilized to perform an analog display using a float that moves up and down inside a glass tube in response to the change in flow rate or pressure, or to convert the change into an electrical signal for calculation processing, and to perform a digital display of the measurement result of the distance.

JP 2001-349719 A JP 2001-165642 A

Conventional air micrometers have been developed to measure the inner diameter of an opening with a single inner diameter, which is generally formed in an object to be measured. For this reason, the measurement head has an outer diameter that corresponds to the inner diameter of the opening of the object to be measured (an outer diameter that is slightly smaller than the inner diameter of the opening), and is configured with air blowing holes at multiple locations around the circumference of the outer periphery.

Meanwhile, there is an increasing demand for air micrometers that can measure the inner diameter of openings even in objects with complex shapes. As an example, when an object to be measured has openings in which a small diameter opening and a large diameter opening are formed in a direction along the axis (center line) on a roughly coaxial basis, there is a demand for an air micrometer that can simultaneously measure the inner diameters of the small diameter opening and the large diameter opening. If the inner diameters of the small diameter opening and the large diameter opening can be measured simultaneously in this way, it is possible to increase the efficiency of the measurement work for measuring the inner diameter of each opening and shorten the time required for measurement.

To meet this demand, it is conceivable to adopt a measuring head in which a small diameter measuring head is inserted into a small diameter opening to measure the inner diameter of the small diameter opening, and a large diameter measuring head is inserted into a large diameter opening to measure the inner diameter of the large diameter opening, and the axes of the two heads are aligned and molded as one unit.

However, there is no guarantee that the small diameter opening and the large diameter opening are formed on the same axis, and there may be misalignment between these openings due to manufacturing errors, etc. If such misalignment occurs, when attempting to insert a small diameter measuring head into a small diameter opening, the end face of the large diameter measuring head may interfere with the opening edge of the large diameter opening, making it impossible to insert each measuring head into each opening. In this case, it becomes impossible to simultaneously measure each inner diameter. Furthermore, even if it is possible to insert each measuring head into each opening, the misalignment may cause the outer peripheral surface of one of the measuring heads to come into sliding contact with the inner peripheral surface of the opening, which may adversely affect the measurement accuracy.

The present invention was made in consideration of these points, and its purpose is to provide an air micrometer measurement head that makes it possible to simultaneously measure the inner diameters of small and large openings with high accuracy.

The solution of the present invention for achieving the above object is premised on a measuring head of an air micrometer configured to be inserted into an opening of an object to be measured and to measure the inner dimension of the opening by blowing compressed air toward the inner surface of the opening. When the object to be measured has a plurality of types of openings with different inner diameters formed in succession, the measuring head of this air micrometer is characterized in that it includes a small diameter measuring head to be inserted into a small diameter opening among the openings and a large diameter measuring head to be inserted into a large diameter opening, and the large diameter measuring head is supported by a first floating mechanism so as to be displaceable relative to the small diameter measuring head in the radial direction.

With this specification, even if there is misalignment between the small diameter opening (hereinafter sometimes simply referred to as the small diameter opening) and the large diameter opening (hereinafter sometimes simply referred to as the large diameter opening) due to manufacturing errors of the object to be measured, the small diameter measuring head can be inserted into the small diameter opening and the large diameter measuring head can be inserted into the large diameter opening by the relative radial displacement of the large diameter measuring head and the small diameter measuring head by the first floating mechanism. This makes it possible to simultaneously measure the inner diameter of the small diameter opening by blowing air from the air blowing hole of the small diameter measuring head toward the inner surface of the small diameter opening, and to measure the inner diameter of the large diameter opening by blowing air from the air blowing hole of the large diameter measuring head toward the inner surface of the large diameter opening with high accuracy.

In addition, a through hole is provided in the axial center portion of the large diameter measuring head, penetrating along the axis, and the small diameter measuring head is inserted into the through hole, and the first floating mechanism is configured by interposing a gasket between the outer surface of the small diameter measuring head and the inner surface of the large diameter measuring head.

According to this configuration, not only is it possible for the measuring heads to be displaced relative to each other in the radial direction due to the elastic deformation of the packing, but it is also possible to seal the gap between the outer surface of the small diameter measuring head and the inner surface of the large diameter measuring head by the packing. As a result, when the measuring air is circulated between the small diameter measuring head and the large diameter measuring head, it is possible to prevent the measuring air from leaking out through the space between the outer surface of the small diameter measuring head and the inner surface of the large diameter measuring head, and it is possible to obtain high measuring accuracy. In addition, since the first floating mechanism is constructed by the packing, it is also possible to reduce the size of this first floating mechanism, thereby saving space and reducing costs.

The small diameter measuring head is supported by a head base member, and the small diameter measuring head is supported by a second floating mechanism so as to be capable of relative displacement in the radial direction with respect to the head base member.

With this configuration, the small diameter measurement head can be easily inserted into the small diameter opening by the relative radial displacement of the small diameter measurement head with respect to the head base member. This makes it possible to more reliably insert each measurement head into each opening, and reliably measure the inner diameter of the small diameter opening and the inner diameter of the large diameter opening simultaneously.

The second floating mechanism in this case is configured to include a pair of races, one of which is fixed to the small diameter measuring head, and the other of which is a thrust bearing fixed to the head base member.

By employing a thrust bearing as the second floating mechanism of the small diameter measuring head, the floating support state of the small diameter measuring head can be stably maintained for a long period of time.

The configuration of the air passages provided inside the small diameter measurement head and the large diameter measurement head constituting the measurement head of the above-mentioned configuration can be given as follows. That is, the small diameter measurement head is formed with a small diameter measurement air blowing hole that blows air toward the inner surface of the small diameter opening, and the large diameter measurement head is formed with a large diameter measurement air blowing hole that blows air toward the inner surface of the large diameter opening. The small diameter measurement head is also provided with a small diameter measurement air passage that extends in a direction along the insertion direction into the small diameter opening and connects to the small diameter measurement air blowing hole, and a large diameter measurement upstream air passage that extends in a direction along the insertion direction to supply measurement air toward the large diameter measurement air blowing hole. The large diameter measurement head is provided with a downstream air passage for large diameter measurement that extends in the direction along the insertion direction and is connected to the air blowing hole for large diameter measurement, and the small diameter measurement head and the large diameter measurement head are each provided with a communication passage that extends in a direction intersecting the insertion direction so as to connect the upstream air passage for large diameter measurement and the downstream air passage for large diameter measurement. The packings are disposed on both sides of the communication passage in the direction along the insertion direction.

According to this configuration, the communication passage that connects the large diameter measurement upstream air passage and the large diameter measurement downstream air passage also communicates with the space between the outer surface of the small diameter measurement head and the inner surface of the large diameter measurement head, and since packings are provided on both sides of this communication passage, it is possible to prevent air from leaking out from the communication passage through the space between the measurement heads to the outside. In other words, the packing can be made to function as both the first floating mechanism and the sealing function that prevents air from leaking out to the outside, and these functions can be realized while saving space.

An air micrometer equipped with a measuring head having the above-mentioned configuration also falls within the scope of the technical idea of the present invention. In other words, it is an air micrometer equipped with a display unit capable of displaying the measurement results of the inner dimensions of the small diameter opening obtained by blowing compressed air from the small diameter measuring head toward the inner surface of the small diameter opening, and the measurement results of the inner dimensions of the large diameter opening obtained by blowing compressed air from the large diameter measuring head toward the inner surface of the large diameter opening.

This makes it possible to realize an air micrometer that can simultaneously measure the inner diameters of small and large openings with high accuracy.

In the present invention, the first floating mechanism supports the large diameter measurement head inserted into the small diameter opening among a plurality of types of openings (a plurality of types of openings having different inner diameter dimensions and continuous with each other) formed in the object to be measured, so that the small diameter measurement head inserted into the large diameter opening can be displaced relative to the small diameter measurement head inserted into the large diameter opening. Therefore, even if there is a misalignment between the small diameter opening and the large diameter opening due to a manufacturing error of the object to be measured, it is possible to insert the small diameter measurement head into the small diameter opening and the large diameter measurement head into the large diameter opening. As a result, it is possible to simultaneously measure the inner diameter of the small diameter opening by blowing air from the air blowing hole of the small diameter measurement head toward the inner surface of the small diameter opening, and to measure the inner diameter of the large diameter opening by blowing air from the air blowing hole of the large diameter measurement head toward the inner surface of the large diameter opening with high accuracy.

1 is a diagram showing an overall configuration of an air micrometer according to an embodiment; FIG. 2 is a block diagram showing an outline of a control system of the air micrometer according to the embodiment. 2 is a cross-sectional view showing the measurement head and its periphery of the air micrometer according to the embodiment. FIG. 4 is a cross-sectional view showing a base end portion of a small diameter measuring head gauge portion and its periphery in the small diameter measuring head according to the embodiment. FIG. 5(a) is a cross-sectional view taken along line a-a in FIG. 3, FIG. 5(b) is a cross-sectional view taken along line bb in FIG. 3, FIG. 5(c) is a cross-sectional view taken along line cc in FIG. 3, FIG. 5(d) is a cross-sectional view taken along line dd in FIG. 3, and FIG. 5(e) is a cross-sectional view taken along line ee in FIG. 3. 6(a) is a cross-sectional view taken along the line ff in FIG. 5(a), FIG. 6(b) is a cross-sectional view taken along the line gg in FIG. 5(a), and FIG. 6(c) is a cross-sectional view taken along the line hh in FIG. 5(a). FIG. 7(a) is a schematic diagram for explaining the air supply path of a vertical blowing system that blows air in a vertical direction, and FIG. 7(b) is a schematic diagram for explaining the air supply path of a horizontal blowing system that blows air in a horizontal direction.

The following describes an embodiment of the present invention with reference to the drawings. This embodiment will be described with an example of a configuration that includes two types of measurement heads, each of which is supported by a floating mechanism. Note that the technical concept of the present invention also includes a configuration that includes three or more types of measurement heads, each of which is supported by a floating mechanism.

- Overall configuration of air micrometer -
First, the overall configuration of an air micrometer equipped with a measuring head according to the present invention will be briefly described. Fig. 1 is a diagram showing the overall configuration of an air micrometer 1 according to this embodiment. As shown in Fig. 1, the air micrometer 1 according to this embodiment is configured to include an air pressure generating source such as a compressor (not shown), a mist separator 2 for collecting mist in compressed air discharged from the air pressure generating source, a regulator 3 for adjusting the compressed air discharged from the air pressure generating source to a set pressure, a measuring head 4 to which air of the set pressure is supplied via the regulator 3, and a control device 5 for converting a pressure change measured through the measuring head 4 when the measuring head 4 is inserted into the openings H1 and H2 of the measurement target W into an electric signal, performing calculation processing based on the converted electric signal, and displaying the calculation result.

The measurement head 4 is arranged to move forward and backward via a moving mechanism (not shown) relative to the measurement object W fixed to the measurement stage of the automated machine.

As shown in FIG. 2, the control device 5 includes an air-electricity conversion means 51 that converts the pressure change measured when the measurement head 4 is inserted into the openings H1 and H2 of the measurement object W into an electrical signal, an analog-digital conversion means 52 that converts the electrical signal converted by the air-electricity conversion means 51 into a digital signal, a measurement data calculation means 53 that receives the digital signal converted by the analog-digital conversion means 52 and includes a CPU, RAM, and ROM that processes the input digital signal according to a pre-installed program, and a measurement data display means 54 such as an LED that displays the results of the calculation process in the measurement data calculation means 53 as a measured value.

Although not shown in detail, a display device such as an LCD monitor and an input device such as a keyboard can be separately connected to the control device 5, and various data can be input through the input device and the results of calculations can be displayed on the display device.

- Measuring head configuration -
Next, a description will be given of the configuration of the measuring head 4, which is a feature of this embodiment. The measuring head 4 according to this embodiment is configured to be capable of simultaneously measuring the inner diameters of two types of openings H1 and H2 having different inner diameters of a measuring object W.

Now, the measurement object W will be described. As shown in FIG. 1, the measurement object W measured using the measurement head 4 according to this embodiment has two types of openings H1 and H2 in the center. Specifically, as shown in FIG. 1, it has a small diameter opening H1 located on the right side (the back side where the measurement head 4 is inserted) and a large diameter opening H2 that is continuous with the left side of the small diameter opening H1 (the front side where the measurement head 4 is inserted) and has a larger diameter than the inner diameter dimension of the small diameter opening H1. These small diameter openings H1 and large diameter openings H2 are formed continuously in a direction along the axis on approximately the same axis. In other words, these small diameter openings H1 and large diameter openings H2 are formed on the same axis with the center lines of their inner surface shapes (the inner edge shapes of the cross sections in a direction along the vertical direction perpendicular to the center lines of each opening H1 and H2) approximately coinciding.

Figure 3 is a cross-sectional view showing the measurement head 4 and its surroundings of the air micrometer 1 according to this embodiment. In this Figure 3, the upper side of the center line O shows the cross section of the measurement head 4 in the vertical direction, and the lower side of the center line O shows the cross section of the measurement head 4 in the horizontal direction. Note that in this Figure 3, the hatching representing the cross section has been partially omitted as necessary (taking into consideration the ease of viewing the air passages formed inside, etc.).

In the following explanation, it is assumed that the measurement head 4 is inserted horizontally into the openings H1 and H2 of the measurement object W, and the right side in FIG. 3 (the side where the measurement head 4 is inserted into the openings H1 and H2 of the measurement object W) will be referred to as the tip side, and the opposite side to the tip side (the left side in FIG. 3) will be referred to as the base side. In addition, when the measurement head 4 is placed horizontally as shown in FIG. 3 (when the extension direction of the center line O is the horizontal direction), the upper side in the vertical direction will be simply referred to as the upper side, and the lower side in the vertical direction will be simply referred to as the lower side. Furthermore, when the measurement head 4 is placed horizontally, the direction around the axis of the measurement head 4 (around the center line O) will be referred to as the circumferential direction.

The measuring head 4 comprises a small diameter measuring head 7 supported via thrust bearings 61, 61 at the tip of the head base member 6 (only the tip portion of the head base member 6 is shown in FIG. 3), and a large diameter measuring head 8 supported on the outer periphery of the small diameter measuring head 7 via a floating mechanism 9 (described later). The head base member 6, small diameter measuring head 7, and large diameter measuring head 8 will each be described in detail below.

(Head base member)
The head base member 6 has a first shaft member 62 located on the base end side (left side in FIG. 3 ) and a second shaft member 63 bolted to the tip side of the first shaft member 62. A space S is provided inside these shaft members 62, 63, through which piping is inserted to supply measurement air (hereinafter, sometimes simply referred to as air) to each of the measuring heads 7, 8.

Thrust bearings 61, 61 are attached to two locations (two locations spaced a predetermined distance apart in the direction along the center line O) on the outer periphery of the second shaft member 63. These thrust bearings 61, 61 are for supporting the small diameter measuring head 7 relative to the head base member 6. Specifically, for example, of the races of each thrust bearing 61, 61, the race located opposite the opposing thrust bearing 61 is fixed to the second shaft member 63.

(Configuration of small diameter measuring head)
The small diameter measuring head 7 is supported by the second shaft member 63 of the head base member 6 via thrust bearings 61, 61, and is configured as a unit in which a plurality of members are integrally assembled.

Specifically, the small diameter measuring head 7 is configured by integrally assembling, in order from the base end side (the side supported by the head base member 6, the left side in FIG. 3), a supported portion 71, a cylindrical portion 72, and a small diameter measuring head main body portion 73.

The supported portion 71 is fixed to the race of the thrust bearings 61, 61. For example, the supported portion 71 is fixed to the race of each thrust bearing 61, 61, which is located on the opposite side of the position facing the thrust bearing 61 on the other side. In this way, one race of each thrust bearing 61, 61 is fixed to the second shaft member 63 of the head base member 6, and the other race is fixed to the supported portion 71 of the small diameter measuring head 7. In general, the thrust bearings 61, 61 allow slight relative movement between the races in the radial direction (relative displacement due to backlash). Therefore, the small diameter measuring head 7 can move slightly relative to the head base member 6 in the radial direction (the axis of the small diameter measuring head 7 can be slightly displaced relative to the axis of the head base member 6). As a result, the thrust bearings 61, 61 function as a floating mechanism, and the small diameter measuring head 7 is supported in a floating state relative to the head base member 6.

The cylindrical portion 72 is a cylindrical member fastened to the end face of the tip side of the supported portion 71 by a bolt B1.

The small diameter measurement head main body 73 is integrally provided with, in order from the base end, a first cylindrical section 74, a second cylindrical section 75, a third cylindrical section 76, and a small diameter measurement head gauge section 77.

The first cylindrical portion 74 is fastened to the end face of the tip side of the cylindrical portion 72 by bolt B2. This first cylindrical portion 74 has a large diameter portion 74a having an outer diameter substantially the same as the outer diameter of the cylindrical portion 72, and a small diameter portion 74b having an outer diameter substantially the same as the inner diameter of the cylindrical portion 72. The small diameter portion 74b is fitted inside the cylindrical portion 72, and the large diameter portion 74a is fastened to the end face of the tip side of the cylindrical portion 72 by bolt B2.

The second cylindrical portion 75 is a cylindrical portion that is continuous with the tip side of the first cylindrical portion 74 and has an outer diameter slightly smaller than the outer diameter of the first cylindrical portion 74.

The third cylindrical portion 76 is a cylindrical portion that is continuous with the tip side of the second cylindrical portion 75 and has an outer diameter slightly smaller than the outer diameter of the second cylindrical portion 75. The third cylindrical portion 76 also has a cylindrical engagement cylindrical portion 76a that is formed with a slightly larger diameter at its tip side. The engagement cylindrical portion 76a is a portion that is used to engage the large diameter measuring head 8 with the small diameter measuring head 7. This engagement state will be described later.

The small diameter measurement head gauge section 77 is a cylindrical portion that continues to the tip side of the third cylindrical section 76 and has an outer diameter smaller than the outer diameter of the third cylindrical section 76. This small diameter measurement head gauge section 77 has a base end section 78 located on the base end side, and a tip section 79 that continues to the tip side of the base end section 78 and has a slightly smaller diameter than the base end section 78.

Figure 4 is a cross-sectional view showing the base end 78 and its surroundings. In this Figure 4 as well, the upper side of the center line O shows the cross section of the measurement head 4 in the vertical direction, and the lower side of the center line O shows the cross section of the measurement head 4 in the horizontal direction.

As shown in FIG. 4, the base end 78 has two recesses 78a, 78b formed around the entire circumference in a direction along the axis of the small diameter measurement head gauge portion 77. Hereinafter, of these recesses 78a, 78b, the recess on the base end side will be referred to as the first recess 78a, and the recess on the tip end side will be referred to as the second recess 78b.

As shown in FIG. 3, near the tip of the tip 79 of the small diameter measurement head gauge section 77, there are air blowing holes (small diameter measurement air blowing holes) 7X, 7Y for blowing air in the horizontal direction and the vertical direction, respectively. In FIG. 3, of these four air blowing holes, only the air blowing hole 7X for blowing air to one side in the horizontal direction and the air blowing hole 7Y for blowing air in the upward direction are shown. In other words, near the tip of the tip 79 of the small diameter measurement head gauge section 77, in addition to the air blowing holes 7X, 7Y shown in FIG. 3, there are also air blowing holes for blowing air to the other side in the horizontal direction and air blowing holes for blowing air downward. The air supply passages that supply air toward these air blowing holes 7X, 7X, 7Y, 7Y will be described later.

(Configuration of large diameter measuring head)
As shown in Fig. 3 and Fig. 4, the large diameter measuring head 8 is provided with a through hole 81 penetrating along the axis (center line O) at the axial center portion. The inner diameter dimension of this through hole 81 is set to be slightly larger than the outer diameter dimension of the small diameter measuring head gauge portion 77. That is, as shown in Fig. 4, this through hole 81 includes a base end side through hole 81a that corresponds to the base end portion 78 of the small diameter measuring head gauge portion 77 and has an inner diameter dimension slightly larger than the outer diameter dimension of the base end portion 78, and a tip end side through hole 81b that corresponds to the tip end portion 79 of the small diameter measuring head gauge portion 77 and has an inner diameter dimension slightly larger than the outer diameter dimension of the tip end portion 79.

The small diameter measuring head gauge part 77 is inserted into the through hole 81 configured in this way. As a result, the base end 78 of the small diameter measuring head gauge part 77 is inserted into the base end side through hole 81a with a small gap, and the tip end 79 of the small diameter measuring head gauge part 77 is inserted into the tip end side through hole 81b with a small gap. In addition, the length dimension (length dimension in the direction along the center line O) of the small diameter measuring head gauge part 77 is set to be longer than the length dimension of the large diameter measuring head 8 by a predetermined dimension (for example, about twice as long). For this reason, as shown in FIG. 3, when the small diameter measuring head gauge part 77 is inserted into the through hole 81 of the large diameter measuring head 8, the tip part of the small diameter measuring head gauge part 77 is located on the tip side of the large diameter measuring head 8, and the air blowing holes 7X and 7Y are located away from the large diameter measuring head 8. The length dimensions of the small diameter measuring head gauge section 77 and the large diameter measuring head 8 are preset according to the shape of the openings H1 and H2 of the measurement object W.

As shown in FIG. 3, the large diameter measuring head 8 includes a large diameter measuring head main body 82 whose outer diameter is approximately equal to that of the engaging cylindrical portion 76a, and a nozzle portion 83 that is continuous with the tip side of the large diameter measuring head main body 82 and has a slightly larger diameter than the large diameter measuring head main body 82.

As shown in FIG. 4, an engagement groove 82a is formed near the base end of the large diameter measuring head body 82, which is recessed over the entire circumferential direction.

The engagement state between the small diameter measuring head 7 and the large diameter measuring head 8 is such that the end face of the tip side of the engagement columnar portion 76a of the small diameter measuring head 7 abuts against the end face of the base side of the large diameter measuring head 8, and the engagement ring member 84 is fitted over the engagement columnar portion 76a of the small diameter measuring head 7 and the engagement groove 82a of the large diameter measuring head 8. In other words, the engagement ring member 84 is provided with a base end locking projection 84a that protrudes toward the inner circumference at the end of the base end, and a tip end locking projection 84b that protrudes toward the inner circumference at the end of the tip end, each over the entire circumferential direction, and the base end locking projection 84a abuts against the end face of the base end of the engagement columnar portion 76a, and the tip end locking projection 84b engages with the engagement groove 82a, thereby engaging the small diameter measuring head 7 and the large diameter measuring head 8.

In addition, on the inner surface of the through hole 81 (more specifically, the base end side through hole 81a) of the large diameter measurement head 8, recesses 81c, 81d are formed around the entire circumference at two locations in the direction along the center line O of the large diameter measurement head 8. Hereinafter, of these recesses 81c, 81d, the recess on the base end side will be referred to as the first recess 81c, and the recess on the tip end side will be referred to as the second recess 81d. The first recess 81c is formed at a position (opposite in the radial direction) facing the first recess 78a in the small diameter measurement head gauge part 77 when the small diameter measurement head 7 and the large diameter measurement head 8 are engaged. In addition, the second recess 81d is formed at a position (opposite in the radial direction) facing the second recess 78b in the small diameter measurement head gauge part 77 when the small diameter measurement head 7 and the large diameter measurement head 8 are engaged.

As shown in FIG. 3, near the tip of the nozzle section 83, there are air outlets (large diameter measurement air outlets) 8X, 8Y for blowing air in the horizontal direction and the vertical direction. In FIG. 3, of these four air outlets, only the air outlet 8X for blowing air to one side in the horizontal direction and the air outlet 8Y for blowing air in the upward direction are shown. In other words, near the tip of the nozzle section 83, in addition to the air outlets 8X, 8Y shown in FIG. 3, there are also air outlets for blowing air to the other side in the horizontal direction and air outlets for blowing air in the downward direction. The air supply passages for supplying air to these air outlets 8X, 8X, 8Y, 8Y will be described later.

As shown in FIG. 4, the inner surface of the through hole 81 (more specifically, the base end through hole 81a) of the large diameter measurement head 8 has packing mounting grooves 85a to 85d formed around the entire circumference at four locations in the direction along the axis of the large diameter measurement head 8. The packing mounting grooves 85a to 85d are formed on both sides of the first recess 81c (both sides in the direction along the axis) and on both sides of the second recess 81d (both sides in the direction along the axis). Hereinafter, of these packing mounting grooves 85a to 85d, the packing mounting groove on the base end side of the first recess 81c will be referred to as the first packing mounting groove 85a, and the packing mounting groove on the tip side of the first recess 81c will be referred to as the second packing mounting groove 85b. Additionally, the packing mounting groove on the base end side of the second recess 81d will be referred to as the third packing mounting groove 85c, and the packing mounting groove on the tip end side of the second recess 81d will be referred to as the fourth packing mounting groove 85d.

The packing grooves 85a to 85d are fitted with rubber packings 91 to 94 that constitute the floating mechanism 9. U-shaped packings (packings with a U-shaped cross section) are used as the packings 91 to 94. Each packing 91 to 94 is fitted so as to open toward the arrangement positions of the recesses 81c and 81d (so that the opening direction of the U-shaped cross section faces the arrangement positions of the recesses 81c and 81d). In other words, the packings 91 and 93 fitted to the first packing mounting groove 85a and the third packing mounting groove 85c are arranged so as to open toward the tip side. Conversely, the packings 92 and 94 fitted to the second packing mounting groove 85b and the fourth packing mounting groove 85d are arranged so as to open toward the base end side. The inner circumferential surface of each packing 91 to 94 abuts against the entire circumferential surface of the small diameter measuring head gauge portion 77 of the small diameter measuring head 7. In addition, the outer peripheral surface of each packing 91-94 abuts over the entire circumferential direction of the inner peripheral surface of the large diameter measuring head 8 (the entire circumferential direction of the bottom surface of the packing mounting grooves 85a-85d). As described above, the inner diameter dimension of the through hole 81 of the large diameter measuring head 8 is set to be slightly larger than the outer diameter dimension of the small diameter measuring head gauge portion 77 of the small diameter measuring head 7. Therefore, the large diameter measuring head 8 is elastically supported by the small diameter measuring head 7 by each packing 91-94 and is supported in a floating state with respect to the small diameter measuring head 7. In other words, the large diameter measuring head 8 is supported so that it can be displaced radially relative to the small diameter measuring head 7.

-Air passage configuration-
Next, the air passages formed inside each of the measuring heads 7 and 8 will be described.

As described above, the tip of the small diameter measurement head gauge section 77 of the small diameter measurement head 7 has four air outlets 7X, 7Y that blow air in the vertical and horizontal directions. The nozzle section 83 of the large diameter measurement head 8 also has four air outlets 8X, 8Y that blow air in the vertical and horizontal directions. In the air micrometer 1 according to this embodiment, air is supplied to each air outlet 7X, 7Y, 8X, 8Y individually, and the inner diameters of the small diameter opening H1 and the large diameter opening H2 are measured based on the pressure change measured when air is blown out from each air outlet. The air passages that supply air to each air outlet 7X, 7Y, 8X, 8Y are described in detail below.

In the space S provided inside the head base member 6, pipes for supplying air to each of the two systems (one system for blowing air vertically and one system for blowing air horizontally) for the small diameter measuring head 7, and pipes for supplying air to each of the two systems (one system for blowing air vertically and one system for blowing air horizontally) for the large diameter measuring head 8 are inserted. These pipes are then connected to the respective air passages via the joint members 100X and 100Y.

Figure 5(a) is a cross-sectional view taken along line a-a in Figure 3, Figure 5(b) is a cross-sectional view taken along line b-b in Figure 3, Figure 5(c) is a cross-sectional view taken along line c-c in Figure 3, Figure 5(d) is a cross-sectional view taken along line d-d in Figure 3, and Figure 5(e) is a cross-sectional view taken along line e-e in Figure 3. Also, Figure 6(a) is a cross-sectional view taken at a position corresponding to line f-f in Figure 5(a), Figure 6(b) is a cross-sectional view taken at a position corresponding to line g-g in Figure 5(a), and Figure 6(c) is a cross-sectional view taken at a position corresponding to line h-h in Figure 5(a). In Figures 5 and 6, hatching representing cross sections has been omitted in consideration of the ease of viewing the air passages formed inside. Furthermore, Figure 7(a) is a schematic diagram for explaining the air supply path of a vertical blowing system that blows air in the vertical direction, and Figure 7(b) is a schematic diagram for explaining the air supply path of a horizontal blowing system that blows air in the horizontal direction.

The air passage of the small diameter measuring head 7 (passage for supplying air toward the air outlets 7X and 7Y) and the air passage of the large diameter measuring head 8 (passage for supplying air toward the air outlets 8X and 8Y) are described below.

(Air passage for small opening measurements)
As shown in Fig. 5(a) and Fig. 7(a), of the joint members 100X, 100Y, 200X, 200Y, the upper joint member 100Y is for supplying air toward the air blowing holes 7Y, 7Y that blow air in the vertical direction in the small diameter measurement head 7. The left joint member 100X in Fig. 5(a) and Fig. 7(b) is for supplying air toward the air blowing holes 7X, 7X that blow air in the horizontal direction in the small diameter measurement head 7.

The air passage (small diameter measurement air passage) 110 connected to the upper joint member 100Y extends inside the second cylindrical portion 75 toward the center of the second cylindrical portion 75 and branches into two systems in the vertical direction (see Figures 5(b), 6(a) and 7(a)). The upper air passage 111 extends inside the third cylindrical portion 76 and inside the small diameter measurement head gauge portion 77 toward the tip side (see Figures 3, 5(c)-(e) and 7(a)) and connects to the air outlet hole 7Y that opens upward (see Figures 3 and 7(a)).

On the other hand, the lower air passage 112 extends through the inside of the third cylindrical section 76 and the inside of the small diameter measurement head gauge section 77 toward the tip side (see Figures 5(c)-(e) and Figure 7(a)), and is connected to the air outlet 7Y that opens downward (see Figure 7(a)). This makes it possible for the air passage 110 connected to the upper joint member 100Y to supply air to the air outlets 7Y, 7Y without being connected to other air passages.

The air passage (small diameter measurement air passage) 120 connected to the left joint member 100X extends inside the second cylindrical portion 75 toward the center of the second cylindrical portion 75 and branches into two systems in the horizontal direction (see Figures 5(b), 6(b), and 7(b)). Specifically, it branches at a position closer to the tip than the branching position of the air passage 110. Of these, the air passage 121 on one side in the horizontal direction extends inside the third cylindrical portion 76 and inside the small diameter measurement head gauge portion 77 toward the tip side (see Figures 3, 5(c)-(e), and 7(b)) and connects to the air outlet 7X that opens to one side in the horizontal direction (see Figures 3 and 7(b)).

On the other hand, the air passage 122 on the other horizontal side extends through the inside of the third cylindrical section 76 and the inside of the small diameter measurement head gauge section 77 toward the tip side (see Figures 5(c)-(e) and Figure 7(b)), and is connected to the air outlet 7X that opens to the other horizontal side (see Figure 7(b)). This makes it possible for the air passage 120 connected to the left joint member 100X to supply air to the air outlets 7X, 7X without being connected to other air passages.

(Air passage for large opening measurements)
As shown in Fig. 5(a) and Fig. 7(a), of the joint members 100X, 100Y, 200X, 200Y, the lower joint member 200Y is for supplying air to the air blowing holes 8Y, 8Y that blow air in the vertical direction in the large diameter measurement head 8. The right joint member 200X in Fig. 5(a) and Fig. 7(b) is for supplying air to the air blowing holes 8X, 8X that blow air in the horizontal direction in the large diameter measurement head 8.

The air passage (upstream air passage for large diameter measurement) 210 connected to the lower joint member 200Y extends toward the tip side and extends toward the center of the second cylindrical portion 75 inside the second cylindrical portion 75 (see Figures 5(b) and 7(a)), and then reaches the inside of the base end portion 78 of the small diameter measurement head gauge portion 77. In addition, the base end portion 78 is provided with an inner communication passage 211 whose inner circumferential side is connected to the air passage 210 and whose outer circumferential side is open to the first recessed portion 78a (see Figures 5(d) and 7(a)). In addition, an air passage (downstream air passage for large diameter measurement) 212 is formed at the top inside the large diameter measurement head 8, one end of which is connected to the upper air blowing hole 8Y and the other end of which reaches the vicinity of the base end of the large diameter measurement head 8 (see Figures 5(e) and 7(a)). Inside the large diameter measuring head 8, an outer communication passage 213 is formed, the outer periphery of which is connected to the air passage 212 and the inner periphery of which is open to the first recess 81c (see Figures 4, 5(d) and 7(a)). As a result, the air passage 210 and the upper air outlet 8Y are connected to each other via the inner communication passage 211, the space between the first recess 78a and the first recess 81c, the outer communication passage 213 and the air passage 212.

On the other hand, an air passage (large diameter measurement downstream air passage) 214 is formed at the bottom inside the large diameter measurement head 8, one end of which is connected to the lower air blowing hole 8Y and the other end of which reaches near the base end of the large diameter measurement head 8 (see Figures 5(e) and 7(a)). Inside this large diameter measurement head 8, an outer communication passage 215 is formed, the outer periphery of which is connected to the air passage 214 and the inner periphery of which is open to the first recess 81c (see Figures 5(d) and 7(a)). As a result, the air passage 210 and the lower air blowing hole 8Y are connected by the inner communication passage 211, the space between the first recess 78a and the second recess 81c, the outer communication passage 215, and the air passage 214.

The air passage (upstream air passage for large diameter measurement) 220 connected to the right joint member 200X extends toward the tip side and extends toward the center of the second cylindrical portion 75 inside the second cylindrical portion 75 (see Figures 5(b) and 7(b)), and then reaches the inside of the base end 78 of the small diameter measurement head gauge portion 77. In addition, this base end 78 is provided with an inner communication passage 221 whose inner circumferential side is connected to the air passage 220 and whose outer circumferential side is open to the second recessed portion 78b (see Figures 5(e) and 7(b)). In addition, on one side of the large diameter measurement head 8 in the horizontal direction, an air passage (downstream air passage for large diameter measurement) 222 is formed, one end of which is connected to the air blowing hole 8X on one side of the horizontal direction and the other end of which reaches the vicinity of the base end of the large diameter measurement head 8 (see Figure 7(b)). Inside the large diameter measuring head 8, an outer communication passage 223 is formed, the outer periphery of which is connected to the air passage 222 and the inner periphery of which is open to the second recess 81d (see Figures 4, 5(e) and 7(b)). As a result, the air passage 220 and the air outlet 8X on one side in the horizontal direction are connected to each other through the inner communication passage 221, the space between the second recess 78b and the second recess 81d, the outer communication passage 223 and the air passage 222.

On the other hand, on the other side of the large diameter measurement head 8 in the horizontal direction, an air passage (large diameter measurement downstream air passage) 224 is formed, one end of which is connected to the air blowing hole 8X on the other side of the horizontal direction and the other end of which reaches the vicinity of the base end of the large diameter measurement head 8 (see FIG. 7(b)). Inside the large diameter measurement head 8, an outer communication passage 225 is provided, the outer circumferential side of which is connected to the air passage 224 and the inner circumferential side of which is open to the second recess 81d (see FIG. 5(e) and FIG. 7(b)). As a result, the air passage 220 and the air blowing hole 8X on the other side of the horizontal direction are connected by the inner communication passage 221, the space between the second recess 78b and the second recess 81d, the outer communication passage 225, and the air passage 224.

With the above configuration, air is supplied individually to each air outlet 7X, 7Y, 8X, 8Y, and the inner diameter of the small diameter opening H1 and the inner diameter of the large diameter opening H2 are measured based on the pressure change measured when air is blown out from each air outlet. Specifically, the measurement data display means 54 is provided with a display unit capable of displaying the measurement result of the inner diameter dimension of the small diameter opening H1 obtained by blowing compressed air from the air outlet 7X, 7Y of the small diameter measurement head 7 toward the inner surface of the small diameter opening H1, and the measurement result of the inner diameter dimension of the large diameter opening H2 obtained by blowing compressed air from the air outlet 8X, 8Y of the large diameter measurement head 8 toward the inner surface of the large diameter opening H2, and the inner diameter dimension of the small diameter opening H1 and the inner diameter dimension of the large diameter opening H2 are displayed on this display unit as the measurement results.

--Effects of the embodiment--
As described above, in this embodiment, the small diameter measurement head 7 is inserted into the small diameter opening H1 formed in the measurement object W, and the large diameter measurement head 8 is inserted into the large diameter opening H2, and is supported by the floating mechanism 9 composed of multiple packings 91 to 94 to enable relative displacement in the radial direction. Therefore, even if there is a misalignment between the small diameter opening H1 and the large diameter opening H2 due to a manufacturing error of the measurement object W, it is possible to insert the small diameter measurement head 7 into the small diameter opening H1 and the large diameter measurement head 8 into the large diameter opening H2. As a result, it is possible to simultaneously measure the inner diameter of the small diameter opening H1 by blowing air from the air blowing holes 7X and 7Y of the small diameter measurement head 7 toward the inner surface of the small diameter opening H1, and to measure the inner diameter of the large diameter opening H2 by blowing air from the air blowing holes 8X and 8Y of the large diameter measurement head 8 toward the inner surface of the large diameter opening H2 with high accuracy.

In this embodiment, the gap between the outer surface of the small diameter measuring head 7 and the inner surface of the large diameter measuring head 8 can be sealed by packings 91 to 94. Specifically, as shown in FIG. 4, the space between the first recess 78a and the first recess 81c is sealed by packings 91 and 92 located on both sides, and the space between the second recess 78b and the second recess 81d is sealed by packings 93 and 94 located on both sides, and each space is isolated from the outside. This makes it possible to prevent the air for measurement from leaking out through the space between the outer surface of the small diameter measuring head 7 and the inner surface of the large diameter measuring head 8, and to obtain high measurement accuracy. In addition, by constructing the floating mechanism 9 using the packings 91 to 94, it is possible to reduce the size of the floating mechanism 9, thereby saving space and reducing costs.

-Other embodiments-
The present invention is not limited to the above-described embodiment, and all modifications and applications within the scope of the claims and equivalents thereto are possible.

For example, in the above embodiment, a thrust bearing 61 was used as the floating mechanism for the small diameter measuring head 7 relative to the head base member 6. The present invention is not limited to this, and a packing may also be used for the floating mechanism for the small diameter measuring head 7.

In addition, in the above embodiment, the measurement head 4 is inserted horizontally into the openings H1 and H2 of the measurement object W. The present invention is not limited to this, and the measurement head 4 may be inserted vertically into the openings H1 and H2 of the measurement object W.

In the above embodiment, U-shaped packings were used as the packings 91 to 94. The present invention is not limited to this, and packings of various shapes can be used. For example, V-shaped or L-shaped packings, or so-called labyrinth seal type packings may be used. In the above embodiment, one packing was provided on each side of the first recess 81c (both sides in the direction along the center line O) and on each side of the second recess 81d. The present invention is not limited to this, and multiple packings may be provided on each side of each recess 81c, 81d.

Furthermore, the floating mechanism 9 (mechanism that supports the measuring head in a floating state using packings 91-94) according to the present invention is not limited to the air micrometer 1 equipped with multiple types of measuring heads 7, 8, but can also be applied to an air micrometer equipped with a single measuring head (an air micrometer for measuring the inner diameter of an opening with a single inner diameter).

The present invention is applicable to the measurement head of an air micrometer that can simultaneously measure the inner diameters of both a small diameter opening and a large diameter opening formed in a measurement object.

1 Air micrometer 4 Measuring head 6 Head base member 61 Thrust bearing 7 Small diameter measuring head 7X, 7Y Air blowing hole (air blowing hole for small diameter measurement)
8 Large diameter measurement head 81 Through holes 8X, 8Y Air blowing holes (air blowing holes for large diameter measurement)
9 Floating mechanism 91-94 Packing 110, 120 Air passage (air passage for small diameter measurement)
210, 220 Air passage (upstream air passage for large diameter measurement)
212, 214, 222, 224 Air passage (downstream air passage for large diameter measurement)
211, 221 Inner passage (passageway)
213, 215, 223, 225 Outside communication passage (communication passage)
W: Measurement object H1: Small diameter opening H2: Large diameter opening

Claims (6)

A measuring head of an air micrometer configured to be inserted into an opening of a measurement object and to blow compressed air toward the inner surface of the opening to measure the inner dimension of the opening,
a plurality of types of openings having different inner diameters are formed in succession in the measurement object,
The measuring head of an air micrometer is provided with a small diameter measuring head which is inserted into the small diameter opening of the openings and a large diameter measuring head which is inserted into the large diameter opening, and the large diameter measuring head is supported by a first floating mechanism so as to be capable of relative radial displacement with respect to the small diameter measuring head. 2. The air micrometer measuring head according to claim 1,
a through hole penetrating along the axis of the large diameter measuring head is provided in an axial center portion of the large diameter measuring head, and the small diameter measuring head is inserted into the through hole;
2. The measuring head of an air micrometer, wherein the first floating mechanism is configured by interposing a packing between an outer surface of the small diameter measuring head and an inner surface of the large diameter measuring head. 3. The measuring head of the air micrometer according to claim 1,
The small diameter measuring head is supported by a head base member,
2. The measuring head of claim 1, wherein the small diameter measuring head is supported by a second floating mechanism so as to be capable of relative displacement in a radial direction with respect to the head base member. 4. The air micrometer measuring head according to claim 3,
The measuring head of an air micrometer, wherein the second floating mechanism comprises a pair of races, one of which is fixed to the small diameter measuring head and the other of which is a thrust bearing fixed to the head base member. 3. The air micrometer measuring head according to claim 2,
The small diameter measurement head is formed with a small diameter measurement air blowing hole for blowing air toward the inner surface of the small diameter opening, and the large diameter measurement head is formed with a large diameter measurement air blowing hole for blowing air toward the inner surface of the large diameter opening,
the small diameter measurement head is provided with a small diameter measurement air passage extending in a direction along the insertion direction into the small diameter opening and connected to the small diameter measurement air blowing hole, and a large diameter measurement upstream air passage extending in a direction along the insertion direction for supplying measurement air toward the large diameter measurement air blowing hole,
The large diameter measurement head is provided with a downstream air passage for large diameter measurement extending in a direction along the insertion direction and connected to the air blowing hole for large diameter measurement,
a communication passage extending in a direction intersecting the insertion direction so as to communicate the large diameter measurement upstream air passage with the large diameter measurement downstream air passage,
2. The measuring head of an air micrometer, wherein the packings are disposed on both sides of the communication passage in the direction along the insertion direction. An air micrometer equipped with the measuring head according to claim 1,
an air micrometer characterized in that it is provided with a display unit capable of displaying the measurement results of the inner dimension of the small diameter opening obtained by blowing compressed air from the small diameter measuring head toward the inner surface of the small diameter opening, and the measurement results of the inner dimension of the large diameter opening obtained by blowing compressed air from the large diameter measuring head toward the inner surface of the large diameter opening.

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