Measurement head of an air micrometer and an air micrometer equipped with the measurement head

Abstract

To provide a measuring head for an air micrometer that enables simultaneous measurement of the inner diameter of each of small and large openings.SOLUTION: A large-diameter measuring head 8, which is inserted into a large-diameter opening of an object to be measured, is supported by a floating mechanism 9 using a packing to enable relative displacement in the radial direction with respect to a small-diameter measuring head 7, which is inserted into a small-diameter opening of the object to be measured. This enables insertion of the small-diameter measuring head 7 into the small-diameter opening and insertion of the large-diameter measuring head 8 into the large-diameter opening, even when there is misalignment between the small-diameter opening and the large-diameter opening. As a result, it is possible to measure the inside diameter of the small opening and the inside diameter of the large opening simultaneously.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a measurement head of an air micrometer and an air micrometer provided with the measurement head. In particular, the present invention relates to an improvement of the measurement head according to the shape of the object to be measured.

Background Art

[0002] Conventionally, air micrometers as disclosed in Patent Document 1 and Patent Document 2 are known. This air micrometer blows compressed air controlled to a constant pressure from the air outlet holes of the measurement head, and when the object to be measured is placed in front of the air outlet holes, depending on the size of the distance between the air outlet holes and the object to be measured, the amount of air blown out and the back pressure change. By utilizing this, an analog display using a float that moves up and down in a glass tube according to the flow rate change or pressure change is performed, or the change is converted into an electrical signal, subjected to arithmetic processing, and a digital display of the measurement result of the interval is performed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventional air micrometers have generally been developed for measuring the inner diameter of a single inner diameter opening formed in an object to be measured. For this reason, as a measurement head, it has an outer diameter corresponding to the inner diameter of the opening of the object to be measured (an outer diameter slightly smaller than the inner diameter of the opening), and air outlet holes are provided at a plurality of locations extending in the circumferential direction on its outer peripheral surface.

[0005] By the way, as an air micrometer, there is an increasing demand for a device that can measure the inner diameter of the opening even for a measurement object with a complex shape. As an example, when an opening is formed in a measurement object such that a small-diameter opening and a large-diameter opening are continuous in a direction along the axis (center line) substantially coaxially, there is a demand for an air micrometer that can simultaneously measure the inner diameters of these small-diameter and large-diameter openings. By enabling simultaneous measurement of the inner diameters of the small-diameter and large-diameter openings in this way, it is possible to improve the efficiency of the measurement operation for measuring the inner diameter of each opening and shorten the time required for measurement.

[0006] In order to meet this requirement, it is conceivable to adopt a measuring head in which a small-diameter measuring head inserted into the small-diameter opening for measuring the inner diameter of the small-diameter opening and a large-diameter measuring head inserted into the large-diameter opening for measuring the inner diameter of the large-diameter opening are integrally formed with their respective axes aligned with each other.

[0007] However, there is no guarantee that the small-diameter opening and the large-diameter opening are necessarily formed coaxially, and there may be a misalignment between these openings due to manufacturing errors or the like. When such a misalignment occurs, when trying to insert the small-diameter measuring head into the small-diameter opening, there is a possibility that the end face of the large-diameter measuring head interferes 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. Also, even if each measuring head could be inserted into each opening, there is a possibility that the outer peripheral surface of any one of the measuring heads and the inner peripheral surface of the opening come into a sliding contact state due to the misalignment, and in this case, it may have an adverse effect on the measurement accuracy.

[0008] The present invention has been made in view of such points, and an object thereof is to provide a measuring head for an air micrometer that enables simultaneous measurement of the inner diameters of a small-diameter opening and a large-diameter opening with high accuracy.

Means for Solving the Problem

[0009] The solution means 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 blow compressed air toward the inner surface of the opening to measure the inner dimensions of the opening. And when a plurality of types of openings with different inner diameters are continuously formed in the object to be measured, the measuring head of this air micrometer includes a small-diameter measuring head inserted into the small-diameter opening and a large-diameter measuring head inserted into the large-diameter opening among the respective openings, and the large-diameter measuring head is First characterized in that it is supported by a floating mechanism so as to be relatively displaceable in the radial direction.

[0010] Due to this specific matter, even when there is a misalignment between the small-diameter opening (hereinafter, may also be simply referred to as the small-diameter opening) and the large-diameter opening (hereinafter, may also be simply referred to as the large-diameter opening) due to manufacturing errors or the like of the object to be measured, First the relative displacement in the radial direction between the large-diameter measuring head and the small-diameter measuring head by the floating mechanism enables the insertion of the small-diameter measuring head into the small-diameter opening and the insertion of the large-diameter measuring head into the large-diameter opening. Thereby, it becomes 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 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.

[0011] Further, a through hole penetrating along the axis is provided in the axial center portion of the large-diameter measuring head, and the small-diameter measuring head is inserted into the through hole, and the First floating mechanism is configured with a packing interposed between the outer surface of the small-diameter measuring head and the inner surface of the large-diameter measuring head.

[0012] According to this configuration, not only is it possible to have a radial relative displacement between the measurement heads as the packing undergoes elastic deformation, but it is also possible to seal between the outer surface of the small-diameter measurement head and the inner surface of the large-diameter measurement head with the packing. As a result, in the case of a configuration where air for measurement flows between the small-diameter measurement head and the large-diameter measurement head, it is possible to suppress the leakage of the measurement air to the outside through the space between the outer surface of the small-diameter measurement head and the inner surface of the large-diameter measurement head, and it is possible to obtain high measurement accuracy. Also, by constructing a First floating mechanism with the packing, First it is also possible to achieve space saving and cost reduction due to the miniaturization of this

[0013] floating mechanism. Second Further, the small-diameter measurement head is supported by a head base member, and the small-diameter measurement head is

[0014] supported by the floating mechanism so as to be relatively displaceable in the radial direction with respect to the head base member.

[0015] According to this configuration, due to the relative displacement in the radial direction of the small-diameter measurement head with respect to the head base member, it becomes possible to easily insert the small-diameter measurement head into the small-diameter opening. As a result, it becomes more reliable to insert each measurement head into each opening, and it becomes possible to reliably perform simultaneous measurement of the inner diameter of the small-diameter opening and the inner diameter of the large-diameter opening. Second In this case, the

[0016] floating mechanism includes a pair of races, with one race fixed to the small-diameter measurement head and the other race fixed to the head base member, and is configured with a thrust bearing. Second By adopting a thrust bearing as the floating mechanism of the small-diameter measurement head, it is possible to stably maintain the floating support state of the small-diameter measurement head over a long period.

[0017] In addition, examples of the configuration of the air passages provided inside each of the small-diameter measurement head and the large-diameter measurement head that constitute the measurement head having the above-described configuration are as follows. That is, the small-diameter measurement head is formed with small-diameter measurement air blowing holes that blow air toward the inner surface of the small-diameter opening, and the large-diameter measurement head is formed with large-diameter measurement air blowing holes that blow air toward the inner surface of the large-diameter opening. Further, the small-diameter measurement head is provided with a small-diameter measurement air passage that extends in a direction along the insertion direction into the small-diameter opening and is connected to the small-diameter measurement air blowing holes, and an upstream-side air passage for large-diameter measurement that extends in a direction along the insertion direction and supplies measurement air toward the large-diameter measurement air blowing holes. Further, the large-diameter measurement head is provided with a downstream-side air passage for large-diameter measurement that extends in a direction along the insertion direction and is connected to the large-diameter measurement air blowing holes, and each of the small-diameter measurement head and the large-diameter measurement head is provided with a communication passage that extends in a direction intersecting the insertion direction so as to communicate the upstream-side air passage for large-diameter measurement and the downstream-side air passage for large-diameter measurement. And the packing is disposed on both sides of the communication passage in the direction along the insertion direction.

[0018] According to this configuration, the communication passage that communicates the upstream-side air passage for large-diameter measurement and the downstream-side air passage for large-diameter measurement 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. However, since the packing is provided on both sides of this communication passage, it is possible to suppress air from leaking to the outside through the space between the measurement heads from the communication passage. That is, the packing can First serve both as a floating mechanism and as a sealing mechanism for suppressing air leakage to the outside, and these functions can be realized while reducing the space.

[0019] Also, an air micrometer equipped with a measuring head having the above-described configuration is also within the scope of the technical idea of the present invention. That is, it is an air micrometer provided with a display unit capable of displaying the measurement result of the dimension inside 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 result of the dimension inside the large-diameter opening obtained by blowing compressed air from the large-diameter measuring head toward the inner surface of the large-diameter opening.

[0020] Thereby, it is possible to realize an air micrometer that can simultaneously measure the inner diameters of the small-diameter opening and the large-diameter opening with high accuracy.

Effects of the Invention

[0021] In the present invention, with respect to the small-diameter measuring 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 being continuous) formed in the object to be measured, the large-diameter measuring head inserted into the large-diameter opening First is supported by a floating mechanism so as to enable relative displacement in the radial direction. Therefore, even when there is a misalignment between the small-diameter opening and the large-diameter opening due to manufacturing errors or the like of the object to be measured, it is possible to insert the small-diameter measuring head into the small-diameter opening and the large-diameter measuring 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 holes of the small-diameter measuring head toward the inner surface of the small-diameter opening, and the inner diameter of the large-diameter opening by blowing air from the air blowing holes of the large-diameter measuring head toward the inner surface of the large-diameter opening with high accuracy.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0023] Hereinafter, embodiments of the present invention will be described with reference to the drawings. This embodiment includes two types of measurement heads, and an example will be described in which each measurement head is supported by a floating mechanism. It should be noted that the technical idea of the present invention also includes a configuration including three or more types of measurement heads, and each measurement head is supported by a floating mechanism.

[0024] -Overall Configuration of the Air Micrometer- First, the overall configuration of the air micrometer equipped with the measurement head according to the present invention will be briefly described. FIG. 1 is a diagram showing the overall configuration of the air micrometer 1 according to the present embodiment. As shown in this FIG. 1, the air micrometer 1 according to the present embodiment includes an air pressure generation source (not shown) such as a compressor, a mist separator 2 that collects mist in the compressed air discharged from the air pressure generation source, a regulator 3 that adjusts the compressed air discharged from the air pressure generation source to a set pressure, a measurement head 4 to which air at the set pressure is supplied via the regulator 3, and a control device 5 that converts the pressure change measured via the measurement head 4 into an electrical signal when the measurement head 4 is inserted into the openings H1, H2 of the measurement object W, performs arithmetic processing based on the converted electrical signal, and displays the arithmetic result.

[0025] The measurement head 4 is provided so as to move forward and backward with respect to the measurement object W fixed to the measurement stage of the automatic machine via a moving mechanism (not shown).

[0026] Further, as shown in FIG. 2, the control device 5 includes an air-electric conversion means 51 that converts the pressure change measured when the measurement head 4 is inserted into the openings H1, 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-electric conversion means 51 into a digital signal, and a measurement data arithmetic means 53 that includes a CPU, a RAM, and a ROM that input the digital signal converted by the analog-digital conversion means 52 and perform arithmetic processing on the input digital signal according to a pre-programmed program, and a measurement data display means 54 such as an LED that displays the result of the arithmetic processing in the measurement data arithmetic means 53 as a measurement value.

[0027] Although not shown in detail, a display device such as a liquid crystal 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 arithmetic result and the like can be displayed on the display device.

[0028] -Configuration of the measurement head- Next, the configuration of the measurement head 4, which is a feature of this embodiment, will be described. The measurement head 4 according to this embodiment is configured to enable simultaneous measurement of the inner diameters of two types of openings H1 and H2 having different inner diameter dimensions in the object to be measured W.

[0029] Here, the object to be measured W will be described. As shown in FIG. 1, the object to be measured W measured using the measurement head 4 according to this embodiment has two types of openings H1 and H2 in its central portion. Specifically, as shown in FIG. 1, 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 (the front side where the measurement head 4 is inserted) of the small-diameter opening H1 and has a larger diameter than the inner diameter dimension of the small-diameter opening H1. These small-diameter opening H1 and large-diameter opening H2 are formed continuously in the direction along the axis on substantially the same axis. In other words, these small-diameter opening H1 and large-diameter opening H2 are formed on the same axis with the center lines in their inner surface shapes (the inner edge shapes of the cross-sections in the direction along the vertical direction perpendicular to the center lines of the respective openings H1 and H2) substantially coinciding.

[0030] FIG. 3 is a cross-sectional view showing the measurement head 4 of the air micrometer 1 according to this embodiment and its periphery. In this FIG. 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 FIG. 3, the hatching representing the cross-section is partially omitted as necessary (considering the visibility of the air passages formed inside, etc.).

[0031] Furthermore, in the following description, it is assumed that the measurement head 4 is inserted into the openings H1 and H2 of the object W to be measured from the horizontal direction. The right side in FIG. 3 (the side where the measurement head 4 is inserted into the openings H1 and H2 of the object W to be measured) is referred to as the tip side, and the side opposite to the tip side (the left side in FIG. 3) is referred to as the base side. Also, as shown in FIG. 3, when the measurement head 4 is placed horizontally (when the extending direction of the center line O is the horizontal direction), the upper side in the vertical direction is simply referred to as the upper side, and the lower side in the vertical direction is 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) is referred to as the circumferential direction.

[0032] The measurement head 4 includes a small-diameter measurement head 7 supported at the tip of a head base member 6 (only the tip-side portion of this head base member 6 is shown in FIG. 3) via thrust bearings 61, 61, and a large-diameter measurement head 8 supported on the outer peripheral side of the small-diameter measurement head 7 via a floating mechanism 9 described later. Hereinafter, the head base member 6, the small-diameter measurement head 7, and the large-diameter measurement head 8 will be specifically described.

[0033] (Head base member) The head base member 6 has a first shaft member 62 located on the base side (the left side in FIG. 3) and a second shaft member 63 bolted to the tip side of the first shaft member 62. Inside these shaft members 62 and 63, a space S is provided through which a pipe for supplying measurement air (hereinafter, sometimes simply referred to as air) toward the respective measurement heads 7 and 8 is inserted.

[0034] Thrust bearings 61, 61 are mounted at two locations on the outer peripheral portion of the second shaft member 63 (two locations at a predetermined interval in the direction along the center line O). These thrust bearings 61, 61 are for supporting the small-diameter measurement head 7 with respect to the head base member 6. Specifically, for example, among the races of each thrust bearing 61, 61, the race located opposite to the other thrust bearing 61 is fixed to the second shaft member 63.

[0035] (Configuration of the Small-Diameter Measurement Head) The small-diameter measurement head 7 is supported with respect to the second shaft member 63 of the head base member 6 via thrust bearings 61, 61, and a plurality of members are integrally assembled to form a unitized configuration.

[0036] Specifically, the small-diameter measurement head 7 is configured by integrally assembling a supported portion 71, a cylindrical portion 72, and a small-diameter measurement head main body portion 73 in order from the proximal end side (the side supported by the head base member 6 and the left side in FIG. 3).

[0037] The supported portion 71 is fixed to the races of the thrust bearings 61, 61. For example, the supported portion 71 is fixed to a race at a position opposite to the position facing the other thrust bearing 61 among the races of each of the thrust bearings 61, 61. In this way, for each of the thrust bearings 61, 61, one race 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 measurement head 7. Generally, the thrust bearings 61, 61 are configured such that the races can move relative to each other slightly in the radial direction (relative displacement due to play). For this reason, the small-diameter measurement head 7 can move relative to the head base member 6 slightly in the radial direction (the axis of the small-diameter measurement head 7 can be displaced slightly with respect to the axis of the head base member 6). As a result, the thrust bearings 61, 61 have a function as a floating mechanism, and the small-diameter measurement head 7 is supported in a floating state with respect to the head base member 6.

[0038] The cylindrical portion 72 is a cylindrical member fastened to the end face on the distal end side of the supported portion 71 by a bolt B1.

[0039] The small-diameter measurement head main body portion 73 is integrally provided with a first cylindrical portion 74, a second cylindrical portion 75, a third cylindrical portion 76, and a small-diameter measurement head gauge portion 77 in order from the proximal end side.

[0040] The first cylindrical portion 74 is fastened to the end face on the tip side of the cylindrical portion 72 by a bolt B2. This first cylindrical portion 74 includes 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 on the tip side of the cylindrical portion 72 by a bolt B2.

[0041] 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.

[0042] 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. Further, this third cylindrical portion 76 includes a cylindrical engaging cylindrical portion 76a formed to be slightly larger in diameter at its tip side. This engaging cylindrical portion 76a is a portion used for engaging the large-diameter measuring head 8 with the small-diameter measuring head 7. This engaging state will be described later.

[0043] The small-diameter measuring head gauge portion 77 is a cylindrical portion that is continuous with the tip side of the third cylindrical portion 76 and has an outer diameter smaller than the outer diameter of the third cylindrical portion 76. This small-diameter measuring head gauge portion 77 includes a base end portion 78 located on the base end side, and a tip end portion 79 that is continuous with the tip side of the base end portion 78 and has a slightly smaller diameter than the base end portion 78.

[0044] FIG. 4 is a cross-sectional view showing the base end portion 78 and its periphery. Also in this FIG. 4, the upper side of the center line O shows the cross-section of the measuring head 4 in the vertical direction, and the lower side of the center line O shows the cross-section of the measuring head 4 in the horizontal direction.

[0045] As shown in FIG. 4, in the base end portion 78, recessed portions 78a and 78b extending over the entire circumference are formed at two locations in the direction along the axis of the small-diameter measuring head gauge portion 77. Hereinafter, among these recessed portions 78a and 78b, the recessed portion on the base end side will be referred to as the first recessed portion 78a, and the recessed portion on the tip side will be referred to as the second recessed portion 78b.

[0046] As shown in FIG. 3, near the tip of the tip portion 79 of the small-diameter measurement head gauge portion 77, air blowing holes (small-diameter measurement air blowing holes) 7X and 7Y for blowing out air in the horizontal direction and the vertical direction respectively are provided. In FIG. 3, only the air blowing hole 7X for blowing out air to one side in the horizontal direction and the air blowing hole 7Y for blowing out air upward among these four-direction air blowing holes appear. That is, near the tip of the tip portion 79 of the small-diameter measurement head gauge portion 77, in addition to the air blowing holes 7X and 7Y appearing in this FIG. 3, an air blowing hole for blowing out air to the other side in the horizontal direction and an air blowing hole for blowing out air downward are also provided. The air supply passage for supplying air toward these air blowing holes 7X, 7X, 7Y, 7Y will be described later.

[0047] (Configuration of large-diameter measurement head) As shown in FIGS. 3 and 4, the large-diameter measurement head 8 is provided with a through hole 81 penetrating along the axis (center line O) in 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 measurement head gauge portion 77. That is, as shown in FIG. 4, as this through hole 81, a base-end side through hole 81a corresponding to the base-end portion 78 of the small-diameter measurement head gauge portion 77 and having an inner diameter dimension slightly larger than the outer diameter dimension of the base-end portion 78, and a tip-side through hole 81b corresponding to the tip portion 79 of the small-diameter measurement head gauge portion 77 and having an inner diameter dimension slightly larger than the outer diameter dimension of the tip portion 79 are provided.

[0048] Then, the small-diameter measurement head gauge portion 77 is inserted into the through-hole 81 configured as described above. As a result, the base end portion 78 of the small-diameter measurement head gauge portion 77 is inserted into the base end side through-hole 81a with a slight gap, and the tip portion 79 of the small-diameter measurement head gauge portion 77 is inserted into the tip side through-hole 81b with a slight gap. Also, the length dimension of the small-diameter measurement head gauge portion 77 (the length dimension in the direction along the center line O) is set to be longer than the length dimension of the large-diameter measurement head 8 by a predetermined dimension (for example, about twice as long). For this reason, as shown in FIG. 3, in the state where the small-diameter measurement head gauge portion 77 is inserted into the through-hole 81 of the large-diameter measurement head 8, the tip portion of the small-diameter measurement head gauge portion 77 is located on the tip side of the large-diameter measurement head 8, and the air blow holes 7X, 7Y are located at positions outside the large-diameter measurement head 8. The length dimensions of the small-diameter measurement head gauge portion 77 and the large-diameter measurement head 8 are preset according to the shapes of the openings H1, H2 of the measurement object W.

[0049] Also, as shown in FIG. 3, the large-diameter measurement head 8 includes a large-diameter measurement head main body portion 82 having an outer diameter dimension substantially matching the outer diameter dimension of the engagement cylindrical portion 76a, and a nozzle portion 83 that is continuous with the tip side of the large-diameter measurement head main body portion 82 and has a slightly larger diameter than the large-diameter measurement head main body portion 82.

[0050] As shown in FIG. 4, an engagement groove 82a that is recessed over the entire circumferential direction is formed in the vicinity of the base end portion of the large-diameter measurement head main body portion 82.

[0051] As for the engagement state between the small-diameter measurement head 7 and the large-diameter measurement head 8, the end face on the tip side of the engagement cylindrical portion 76a in the small-diameter measurement head 7 is brought into contact with the end face on the base end side of the large-diameter measurement head 8, and an engagement ring member 84 is externally fitted straddling the engagement cylindrical portion 76a of the small-diameter measurement head 7 and the engagement groove 82a of the large-diameter measurement head 8. That is, on the engagement ring member 84, a base-end-side locking projection 84a that projects inward on the inner peripheral side at the end portion on the base end side and a tip-side locking projection 84b that projects inward on the inner peripheral side at the end portion on the tip side are provided over the entire circumferential direction. The base-end-side locking projection 84a abuts against the end face on the base end side of the engagement cylindrical portion 76a, and the tip-side locking projection 84b engages with the engagement groove 82a, thereby engaging the small-diameter measurement head 7 and the large-diameter measurement head 8.

[0052] Further, 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, recessed portions 81c and 81d extending over the entire circumference are formed at two positions in the direction along the center line O of the large-diameter measurement head 8. Hereinafter, among these recessed portions 81c and 81d, the recessed portion on the base end side will be referred to as the first recessed portion 81c, and the recessed portion on the tip side will be referred to as the second recessed portion 81d. The first recessed portion 81c is formed at a position (a position facing in the radial direction) facing the first recessed portion 78a in the small-diameter measurement head gauge portion 77 in the engagement state between the small-diameter measurement head 7 and the large-diameter measurement head 8. The second recessed portion 81d is formed at a position (a position facing in the radial direction) facing the second recessed portion 78b in the small-diameter measurement head gauge portion 77 in the engagement state between the small-diameter measurement head 7 and the large-diameter measurement head 8.

[0053] As shown in FIG. 3, near the tip of the nozzle portion 83, air blowing holes (air blowing holes for large diameter measurement) 8X and 8Y for blowing air in the horizontal direction and the vertical direction respectively are provided. In FIG. 3, only the air blowing hole 8X for blowing air to one side in the horizontal direction and the air blowing hole 8Y for blowing air upward among these four-direction air blowing holes appear. That is, near the tip of the nozzle portion 83, in addition to the air blowing holes 8X and 8Y shown in FIG. 3, air blowing holes for blowing air to the other side in the horizontal direction and air blowing holes for blowing air downward are also provided. The air supply passages for supplying air to these air blowing holes 8X, 8X, 8Y, 8Y will be described later.

[0054] And, as shown in FIG. 4, 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, packing mounting grooves 85a to 85d extending over the entire circumference are formed at four locations in the direction along the axis of the large diameter measurement head 8. The formation positions of these packing mounting grooves 85a to 85d are on both sides (both sides in the direction along the axis) of the first recessed portion 81c and on both sides (both sides in the direction along the axis) of the second recessed portion 81d. Hereinafter, among these packing mounting grooves 85a to 85d, the packing mounting groove on the base end side of the first recessed portion 81c will be referred to as the first packing mounting groove 85a, and the packing mounting groove on the tip side of the first recessed portion 81c will be referred to as the second packing mounting groove 85b. Also, the packing mounting groove on the base end side of the second recessed portion 81d will be referred to as the third packing mounting groove 85c, and the packing mounting groove on the tip side of the second recessed portion 81d will be referred to as the fourth packing mounting groove 85d.

[0055] In each of these packing mounting grooves 85a to 85d, rubber packings 91 to 94 that constitute the floating mechanism 9 are mounted. As each of the packings 91 to 94, U-shaped packings (packings with a U-shaped cross-section) are applied. Each of the packings 91 to 94 is mounted so as to open toward the arrangement positions of the recessed portions 81c and 81d (so that the opening direction of the U-shaped cross-section faces the arrangement positions of the recessed portions 81c and 81d). That is, the packings 91 and 93 mounted in the first packing mounting groove 85a and the third packing mounting groove 85c, respectively, are arranged so as to open toward the tip side. Conversely, the packings 92 and 94 mounted in the second packing mounting groove 85b and the fourth packing mounting groove 85d, respectively, are arranged so as to open toward the base end side. The inner peripheral surfaces of each of the packings 91 to 94 are in contact with the entire outer peripheral surface of the small-diameter measuring head gauge portion 77 of the small-diameter measuring head 7 in the circumferential direction. Further, the outer peripheral surfaces of each of the packings 91 to 94 are in contact with the entire inner peripheral surface of the large-diameter measuring head 8 in the circumferential direction (the entire circumferential direction of the bottom surface of the packing mounting grooves 85a to 85d). Also, 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. For this reason, the large-diameter measuring head 8 is elastically supported by each of the packings 91 to 94 on the small-diameter measuring head 7 and is supported in a floating state with respect to the small-diameter measuring head 7. That is, the large-diameter measuring head 8 is supported with respect to the small-diameter measuring head 7 so as to be capable of relative displacement in the radial direction.

[0056] -Configuration of Air Passage- Next, the air passages formed inside each of the measuring heads 7 and 8 will be described.

[0057] As described above, four air blowout holes 7X and 7Y for blowing out air in the vertical and horizontal directions, respectively, are formed at the tip of the small-diameter measurement head gauge portion 77 of the small-diameter measurement head 7. Further, four air blowout holes 8X and 8Y for blowing out air in the vertical and horizontal directions, respectively, are also formed in the nozzle portion 83 of the large-diameter measurement head 8. In the air micrometer 1 according to the present embodiment, air is individually supplied to each of the air blowout holes 7X, 7Y, 8X, and 8Y, and the inner diameters of the small-diameter opening H1 and the large-diameter opening H2 are measured based on the pressure changes measured in a state where air is blown out from each of them. Hereinafter, the air passages for supplying air to each of the air blowout holes 7X, 7Y, 8X, and 8Y will be specifically described.

[0058] In the space S provided inside the head base member 6, pipes for supplying air to two systems (a system for blowing out air in the vertical direction and a system for blowing out air in the horizontal direction) for the small-diameter measurement head 7, and pipes for supplying air to two systems (a system for blowing out air in the vertical direction and a system for blowing out air in the horizontal direction) for the large-diameter measurement head 8 are inserted. Then, these pipes are connected to the respective air passages via the joint members 100X and 100Y.

[0059] 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 b-b in FIG. 3, FIG. 5(c) is a cross-sectional view taken along line c-c in FIG. 3, FIG. 5(d) is a cross-sectional view taken along line d-d in FIG. 3, and FIG. 5(e) is a cross-sectional view taken along line e-e in FIG. 3. Further, FIG. 6(a) is a cross-sectional view at a position corresponding to line f-f in FIG. 5(a), FIG. 6(b) is a cross-sectional view at a position corresponding to line g-g in FIG. 5(a), and FIG. 6(c) is a cross-sectional view at a position corresponding to line h-h in FIG. 5(a). Also in FIGS. 5 and 6, hatching representing the cross-section is omitted in consideration of the visibility of air passages and the like formed inside. Furthermore, FIG. 7(a) is a schematic diagram for explaining the air supply path of the vertical blowing system that blows air in the vertical direction, and FIG. 7(b) is a schematic diagram for explaining the air supply path of the horizontal blowing system that blows air in the horizontal direction.

[0060] Hereinafter, the air passage of the small-diameter measurement head 7 (the passage for supplying air toward the air blowing holes 7X and 7Y) and the air passage of the large-diameter measurement head 8 (the passage for supplying air toward the air blowing holes 8X and 8Y) will be described respectively.

[0061] (Air passage for small-diameter opening measurement) As shown in FIGS. 5(a) and 7(a), among the joint members 100X, 100Y, 200X, and 200Y, the upper joint member 100Y is for supplying air toward the air blowing holes 7Y and 7Y that blow air in the vertical direction in the small-diameter measurement head 7. Also, the left joint member 100X in FIGS. 5(a) and 7(b) is for supplying air toward the air blowing holes 7X and 7X that blow air in the horizontal direction in the small-diameter measurement head 7.

[0062] The air passage (air passage for small-diameter measurement) 110 connected to the upper joint member 100Y extends toward the center of the second cylindrical portion 75 inside the second cylindrical portion 75 and is branched into two systems in the vertical direction (see FIGS. 5(b), 6(a), and 7(a)). Among them, the upper air passage 111 extends toward the tip side inside the third cylindrical portion 76 and inside the small-diameter measurement head gauge portion 77 (see FIGS. 3, 5(c)-(e), and 7(a)), and is connected to the air blowing hole 7Y that opens upward (see FIGS. 3 and 7(a)).

[0063] On the other hand, the lower air passage 112 extends toward the tip side inside the third cylindrical portion 76 and inside the small-diameter measurement head gauge portion 77 (see FIGS. 5(c)-(e) and 7(a)), and is connected to the air blowing hole 7Y that opens downward (see FIG. 7(a)). Thus, the air passage 110 connected to the upper joint member 100Y can supply air to the air blowing holes 7Y, 7Y without communicating with other air passages.

[0064] Also, the air passage (air passage for small-diameter measurement) 120 connected to the left joint member 100X extends toward the center of the second cylindrical portion 75 inside the second cylindrical portion 75 and is branched into two systems in the horizontal direction (see FIGS. 5(b), 6(b), and 7(b)). Specifically, it is branched at a position on the tip side from the branching position of the air passage 110. Among them, the air passage 121 on one side in the horizontal direction extends toward the tip side inside the third cylindrical portion 76 and inside the small-diameter measurement head gauge portion 77 (see FIGS. 3, 5(c)-(e), and 7(b)), and is connected to the air blowing hole 7X that opens on one side in the horizontal direction (see FIGS. 3 and 7(b)).

[0065] On the other hand, the air passage 122 on the other side in the horizontal direction extends toward the tip side inside the third cylindrical portion 76 and inside the small-diameter measurement head gauge portion 77 (see FIGS. 5(c) to (e) and 7(b)), and is connected to the air blowing holes 7X that open to the other side in the horizontal direction (see FIG. 7(b)). As a result, the air passage 120 connected to the left joint member 100X can supply air to the air blowing holes 7X, 7X without communicating with other air passages.

[0066] (Air passage for measuring large-diameter opening) As shown in FIGS. 5(a) and 7(a), among the joint members 100X, 100Y, 200X, and 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. Also, the right joint member 200X in FIGS. 5(a) and 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.

[0067] 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 FIGS. 5(b) and 7(a)), and then reaches inside the base end portion 78 of the small-diameter measurement head gauge portion 77. Further, an inner communication passage 211 is provided at this base end portion 78, with the inner peripheral side communicating with the air passage 210 and the outer peripheral side opening to the first recessed portion 78a (see FIGS. 5(d) and 7(a)). Also, an air passage (downstream air passage for large-diameter measurement) 212 is formed in the upper part inside the large-diameter measurement head 8, with one end communicating with the upper air blowing hole 8Y and the other end reaching near the base end portion of the large-diameter measurement head 8 (see FIGS. 5(e) and 7(a)). And an outer communication passage 213 is formed inside this large-diameter measurement head 8, with the outer peripheral side communicating with the air passage 212 and the inner peripheral side opening to the first recessed portion 81c (see FIGS. 4, 5(d) and 7(a)). Thus, the air passage 210 and the upper air blowing hole 8Y are communicated by the inner communication passage 211, the space between the first recessed portion 78a and the first recessed portion 81c, the outer communication passage 213, and the air passage 212.

[0068] On the other hand, an air passage (downstream air passage for large-diameter measurement) 214 is formed in the lower part inside the large-diameter measurement head 8, with one end communicating with the lower air blowing hole 8Y and the other end reaching near the base end portion of the large-diameter measurement head 8 (see FIGS. 5(e) and 7(a)). And an outer communication passage 215 is formed inside this large-diameter measurement head 8, with the outer peripheral side communicating with the air passage 214 and the inner peripheral side opening to the first recessed portion 81c (see FIGS. 5(d) and 7(a)). Thus, the air passage 210 and the lower air blowing hole 8Y are communicated by the inner communication passage 211, the space between the first recessed portion 78a and the second recessed portion 81c, the outer communication passage 215, and the air passage 214.

[0069] Also, an 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 FIGS. 5(b) and 7(b)). Then, it reaches inside the base end portion 78 of the small-diameter measurement head gauge portion 77. Further, an inner communication passage 221 is provided at this base end portion 78, with the inner peripheral side communicating with the air passage 220 and the outer peripheral side opening to the second recessed portion 78b (see FIGS. 5(e) and 7(b)). Also, on one side in the horizontal direction inside the large-diameter measurement head 8, an air passage (downstream air passage for large-diameter measurement) 222 is formed, with one end communicating with the air outlet hole 8X on one side in the horizontal direction and the other end reaching near the base end portion of the large-diameter measurement head 8 (see FIG. 7(b)). And inside this large-diameter measurement head 8, an outer communication passage 223 is formed, with the outer peripheral side communicating with the air passage 222 and the inner peripheral side opening to the second recessed portion 81d (see FIGS. 4, 5(e) and 7(b)). Thus, the air passage 220 and the air outlet hole 8X on one side in the horizontal direction are communicated by the inner communication passage 221, the space between the second recessed portion 78b and the second recessed portion 81d, the outer communication passage 223, and the air passage 222.

[0070] On the other hand, on the other side in the horizontal direction inside the large-diameter measurement head 8, an air passage (downstream air passage for large-diameter measurement) 224 is formed, with one end communicating with the air outlet hole 8X on the other side in the horizontal direction and the other end reaching near the base end portion of the large-diameter measurement head 8 (see FIG. 7(b)). And inside this large-diameter measurement head 8, an outer communication passage 225 is provided, with the outer peripheral side communicating with the air passage 224 and the inner peripheral side opening to the second recessed portion 81d (see FIGS. 5(e) and 7(b)). Thus, the air passage 220 and the air outlet hole 8X on the other side in the horizontal direction are communicated by the inner communication passage 221, the space between the second recessed portion 78b and the second recessed portion 81d, the outer communication passage 225, and the air passage 224.

[0071] With the above configuration, air is individually supplied to each of the air outlet holes 7X, 7Y, 8X, and 8Y, and the inner diameter of the small-diameter opening H1 and the inner diameter of the large-diameter opening H2 are each measured based on the pressure change measured in the state where air is blown out from each of them. Specifically, the measurement data display means 54 has a display unit capable of displaying, respectively, the measurement result of the inner diameter dimension of the small-diameter opening H1 obtained by blowing compressed air from the air outlet holes 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 holes 8X, 8Y of the large-diameter measurement head 8 toward the inner surface of the large-diameter opening H2. The inner diameter dimension of the small-diameter opening H1 and the inner diameter dimension of the large-diameter opening H2 as measurement results are each displayed on this display unit.

[0072] - Effects of the Embodiment - As described above, in this embodiment, the large-diameter measurement head 8 inserted into the large-diameter opening H2 is supported by the floating mechanism 9 composed of a plurality of packings 91 to 94 so as to be capable of relative displacement in the radial direction with respect to the small-diameter measurement head 7 inserted into the small-diameter opening H1 formed in the measurement object W. Therefore, even when there is a misalignment between the small-diameter opening H1 and the large-diameter opening H2 due to manufacturing errors or the like 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 becomes possible to simultaneously measure the inner diameter of the small-diameter opening H1 by blowing air from the air outlet holes 7X, 7Y of the small-diameter measurement head 7 toward the inner surface of the small-diameter opening H1 and the inner diameter of the large-diameter opening H2 by blowing air from the air outlet holes 8X, 8Y of the large-diameter measurement head 8 toward the inner surface of the large-diameter opening H2 with high accuracy.

[0073] Also, in the present embodiment, it is also possible to seal the space between the outer surface of the small-diameter measurement head 7 and the inner surface of the large-diameter measurement head 8 with packings 91 to 94. Specifically, as shown in FIG. 4, the space between the first recessed portion 78a and the first recessed portion 81c is sealed by the packings 91 and 92 located on both sides thereof, and the space between the second recessed portion 78b and the second recessed portion 81d is sealed by the packings 93 and 94 located on both sides thereof, and each space is blocked from the outside. Thereby, it is possible to suppress the measurement air from leaking to the outside through the space between the outer surface of the small-diameter measurement head 7 and the inner surface of the large-diameter measurement head 8, and it is possible to obtain high measurement accuracy. Further, by constructing the floating mechanism 9 with the packings 91 to 94, it is also possible to achieve space saving and cost reduction by miniaturizing the floating mechanism 9.

[0074] -Other Embodiments- Note that the present invention is not limited to the above-described embodiment, and all modifications and applications included in the scope of the claims and the scope equivalent thereto are possible.

[0075] For example, in the above-described embodiment, the thrust bearing 61 was used as the floating mechanism of the small-diameter measurement head 7 with respect to the head base member 6. The present invention is not limited to this, and packings may also be used for the floating mechanism of the small-diameter measurement head 7.

[0076] Also, in the above-described embodiment, the measurement head 4 was inserted from the horizontal direction with respect to 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 from the vertical direction with respect to the openings H1 and H2 of the measurement object W.

[0077] In the above-described embodiment, U-shaped packings were applied as the packings 91 to 94. The present invention is not limited to this, and packings of various shapes can be applied. For example, V-shaped or L-shaped packings, or so-called labyrinth seal type packings may be applied. Further, in the above-described embodiment, one packing was disposed on each side of the first recessed portion 81c (both sides in the direction along the center line O) and on each side of the second recessed portion 81d. The present invention is not limited to this, and a plurality of packings may be disposed on each side of each of the recessed portions 81c and 81d.

[0078] Further, the floating mechanism (mechanism for supporting the measurement head in a floating state using the packings 91 to 94) 9 according to the present invention is applicable not only to the air micrometer 1 provided with a plurality of types of measurement heads 7 and 8, but also to an air micrometer provided with a single measurement head (an air micrometer for measuring the inner diameter of an opening having a single inner diameter).

Industrial Applicability

[0079] The present invention is applicable to the measurement head of an air micrometer capable of simultaneously measuring the inner diameters of a small-diameter opening and a large-diameter opening formed in an object to be measured.

Explanation of Reference Numerals

[0080] 1 Air micrometer 4 Measurement head 6 Head base member 61 Thrust bearing 7 Small-diameter measurement head 7X, 7Y Air blow holes (air blow holes for small-diameter measurement) 8 Large-diameter measurement head 81 Through hole 8X, 8Y Air blow holes (air blow holes for large-diameter measurement) 9 Floating mechanism 91 to 94 Packings 110, 120 Air passages (air passages 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 communication passage (communication passage) 213, 215, 223, 225 Outer communication passage (communication passage) W Object to be measured H1 Small-diameter opening H2 Large-diameter opening

Claims

1. In a measuring head of an air micrometer configured to measure the inner diameter of an opening by inserting into the opening of an object to be measured and blowing compressed air toward the inner surface of the opening, the object to be measured has a plurality of types of openings with different inner diameters formed continuously, the measuring head includes a small-diameter measuring head inserted into the small-diameter opening and a large-diameter measuring head inserted into the large-diameter opening among the respective openings, and the large-diameter measuring head is supported by a first floating mechanism so as to be relatively displaceable in the radial direction with respect to the small-diameter measuring head. The measuring head of the air micrometer is characterized by this.

2. In the measuring head of the air micrometer according to Claim 1, a through hole penetrating along the axis is provided in the axial center portion of the large-diameter measuring head, and the small-diameter measuring head is inserted into the through hole, the first floating mechanism is configured such that a packing is interposed between the outer surface of the small-diameter measuring head and the inner surface of the large-diameter measuring head. The measuring head of the air micrometer is characterized by this.

3. In the measuring head of the air micrometer according to Claim 1 or 2, the small-diameter measuring head is supported by a head base member, the small-diameter measuring head is supported by a second floating mechanism so as to be relatively displaceable in the radial direction with respect to the head base member. The measuring head of the air micrometer is characterized by this.

4. In the measuring head of the air micrometer according to Claim 3, the second floating mechanism includes a pair of races, and is configured to include a thrust bearing in which one race is fixed to the small-diameter measuring head and the other race is fixed to the head base member. The measuring head of the air micrometer is characterized by this.

5. In the measuring head of the air micrometer according to Claim 2, a small-diameter air blowing hole for blowing air toward the inner surface of the small-diameter opening is formed in the small-diameter measuring head, and a large-diameter air blowing hole for blowing air toward the inner surface of the large-diameter opening is formed in the large-diameter measuring head. The small-diameter measurement head is provided with a small-diameter measurement air passage that extends in a direction along the insertion direction into the opening of the small diameter and leads to the small-diameter measurement air blowing holes, and a large-diameter measurement upstream air passage that extends in a direction along the insertion direction and supplies measurement air toward the large-diameter measurement air blowing holes. The large-diameter measurement head is provided with a large-diameter measurement downstream air passage that extends in a direction along the insertion direction and leads to the large-diameter measurement air blowing holes. Each of the small-diameter measurement head and the large-diameter measurement head is provided with a communication passage that extends in a direction intersecting the insertion direction so as to communicate the large-diameter measurement upstream air passage and the large-diameter measurement downstream air passage. The packing is disposed on both sides of the communication passage in the direction along the insertion direction, and is a measurement head of an air micrometer.

6. An air micrometer comprising the measurement head according to claim 1, characterized in that it is provided with a display unit capable of respectively displaying the measurement result of the dimension inside the opening of the small diameter obtained by blowing compressed air from the small-diameter measurement head toward the inner surface of the opening of the small diameter, and the measurement result of the dimension inside the opening of the large diameter obtained by blowing compressed air from the large-diameter measurement head toward the inner surface of the opening of the large diameter.

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