Ultrasonic propagation member and ultrasonic measurement structure

Abstract

To provide an ultrasonic wave propagation member which can desirably measure a small object.SOLUTION: An ultrasonic wave propagation member 3A includes: an ultrasonic wave propagation unit 20A having an end surface 23a and an end surface 21a provided on the opposite sides to each other, the end surface 23a being a first contact surface in contact with a bolt 2 as a measurement target and the end surface 21a being a second contact surface in contact with an end surface 14a as a top end surface of an ultrasonic wave detector 10; and a holding unit 30A for holding the ultrasonic wave propagation unit 20A, the holding unit having an end surface 35a as a third contact surface in contact with the measurement target object in an outer side in a radial direction than the first contact surface. The first contact surface is smaller than the top end surface.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a member for propagating ultrasonic waves generated by an ultrasonic probe to a measurement object, and a structure for measuring a measurement object using ultrasonic waves.

Background Art

[0002] When measuring the bolt (tightening) axial force during bolt tightening, an elastomer member is installed to fill the gap between the ultrasonic probe and the bolt head (see Patent Document 1). Since such an elastomer member is used in a state of being compressed and deformed under a load between the ultrasonic probe and the measurement object (bolt), it has been difficult to achieve both measurement performance and durability.

[0003] On the other hand, the applicant of the present application has developed an ultrasonic propagation member capable of achieving both measurement performance and durability (see Patent Document 2). The ultrasonic propagation member includes an ultrasonic propagation part having a first contact surface that contacts a measurement object and a second contact surface that is provided on the opposite side of the first contact surface and contacts the tip surface of the ultrasonic probe, and a holding part that holds the ultrasonic propagation part and has a third contact surface that contacts the measurement object on the radially outer side of the first contact surface. In such an ultrasonic propagation member, the ultrasonic propagation part is softer than the holding part.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Patent Document 2 describes an ultrasonic propagation member applicable when, in the shape in the axial view, the portion of the object to be measured that contacts the ultrasonic propagation member is larger than the tip surface of the ultrasonic probe. Such an ultrasonic propagation member cannot correspond to a small object to be measured.

[0006] The present invention was conceived in view of the above-described matters, and an object thereof is to provide an ultrasonic propagation member and an ultrasonic measurement structure capable of suitably measuring a small object to be measured.

Means for Solving the Problems

[0007] In order to solve the above-described problems, the ultrasonic propagation member of the present invention includes an ultrasonic propagation part having a first contact surface that contacts an object to be measured and a second contact surface that is provided on the opposite side of the first contact surface and contacts the tip surface of the ultrasonic probe, and a holding part that holds the ultrasonic propagation part and has a third contact surface that contacts the object to be measured on the radially outer side of the first contact surface. The first contact surface is... Small, the ultrasonic propagation part has a constant-shape part with the same shape extending from the second contact surface toward the first contact surface side at an end on the second contact surface side in the ultrasonic propagation part, the thickness of the constant-shape part is 1 / 12 or more of the diameter of the second contact surface, and the holding part contacts an end surface on the first contact surface side in the constant-shape part characterized in that...

Effects of the Invention

[0008] According to the present invention, a small object to be measured can be suitably measured.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described by taking as an example a case where a bolt is adopted as a measurement object and a bolt axial force is measured using an ultrasonic probe, with appropriate reference to the drawings. The same reference numerals are given to the same components, and duplicate explanations are omitted. Note that the measurement object of the present invention is not limited to a bolt, and the ultrasonic propagation member and the ultrasonic measurement structure of the present invention are applicable to an apparatus for measuring dimensions, axial force, etc. of a measurement object using an ultrasonic probe.

[0011] <First Embodiment> As shown in Fig. 1, the tightening device (nut runner) 1A as an ultrasonic measurement structure according to the first embodiment of the present invention is also a bolt axial force measurement device that measures the bolt (tightening) axial force generated when tightening the bolt 2. The bolt axial force measurement device rotates the tightening device 1A attached to the bolt 2 by driving a drive unit (such as a motor) not shown by a control unit not shown to tighten the bolt 2. The control unit of the bolt axial force measurement device calculates the bolt axial force based on the echo of the ultrasonic pulse during bolt tightening. The tightening device (ultrasonic measurement structure) 1A includes a rotation shaft and socket not shown, an ultrasonic probe 10, and an ultrasonic propagation member 3A. The rotation shaft, the ultrasonic probe 10, and the ultrasonic propagation member 3A are arranged coaxially with each other, and are arranged coaxially with respect to the bolt 2 in the axial force measurement stage.

[0012] <Rotating shaft> The rotating shaft is a cylindrical member that rotates around the axis of the rotating shaft at a predetermined torque and rotational speed (rotational angular velocity) under the control of a control unit not shown.

[0013] <Socket> The socket is a cylindrical member that is externally fitted to the rotating shaft and the bolt 2. The base end portion (upper end portion) of the socket 4 is detachably externally fitted to and fixed to the tip end portion (lower end portion) of the rotating shaft. The tip end portion (lower end portion) of the socket can be externally fitted to the head portion 2a of the bolt 2.

[0014] <Ultrasonic probe> The ultrasonic probe 10 is a substantially cylindrical member attached to the tip end portion (lower end portion) of the rotating shaft within the socket. The ultrasonic probe 10 measures the characteristics (here, the axial force) of the measurement object (bolt 2) using ultrasonic waves, and includes a piezoelectric element or the like that oscillates an ultrasonic pulse and receives the echo of the oscillated ultrasonic pulse. The ultrasonic probe 10 may be attached to the tip end portion of the rotating shaft via a support member, a resilient coil spring, etc. not shown.

[0015] As shown in FIG. 2, the ultrasonic probe 10 integrally and coaxially includes a first outer diameter portion 11, a second outer diameter portion 12, a third outer diameter portion (large diameter portion) 13, and a fourth outer diameter portion (small diameter portion) 14 in order from the base end portion (upper end portion) side which is the rotation shaft side toward the tip end portion (lower end portion) side which is the bolt 2 side.

[0016] ≪First outer diameter portion≫ The first outer diameter portion 11 is a portion that is exposed from the holding portion 30A and attached to the tip end portion (lower end portion) of the rotation shaft. The first outer diameter portion 11 has an outer diameter of φ 11 and has a cylindrical shape. That is, the first outer diameter portion 11 has the same shape (circular shape) in the axial direction. In other words, the shape of the cross section orthogonal to the axis of the first outer diameter portion 11 is the same at each position in the axial direction (even when the axial position is changed). The shape of the first outer diameter portion 11 is not limited to the illustrated one, and can exhibit various shapes that can be attached to the rotation shaft.

[0017] ≪Second outer diameter portion≫ The second outer diameter portion 12 is a portion that is exposed from the holding portion 30A and contacts the end face 31a of the holding portion 30A. The second outer diameter portion 12 has an outer diameter of φ 12 and has a disk shape. That is, the second outer diameter portion 12 has the same shape (circular shape) in the axial direction. In other words, the shape of the cross section orthogonal to the axis of the second outer diameter portion 12 is the same at each position in the axial direction (even when the axial position is changed). The second outer diameter portion 12 has a larger diameter than the first outer diameter portion 11 and the third outer diameter portion 13, and a flange portion having an annular shape is formed by a portion that protrudes radially from the first outer diameter portion 11 and the third outer diameter portion 13. The end face 12a on the tip end portion side in the flange portion of the second outer diameter portion 12 is parallel to the end face (the tip end face of the ultrasonic probe 10) 14a of the fourth outer diameter portion 14.

[0018] ≪Third outer diameter portion≫ The third outer diameter portion 13 is a portion that is housed and held in the holding portion 30A. The third outer diameter portion 13 has an outer diameter of φ 13 and an axial dimension L 13It has a substantially cylindrical shape. That is, the third outer diameter portion 13 has substantially the same shape (circular shape) in the axial direction. In other words, the shape of the cross section orthogonal to the axis of the third outer diameter portion 13 is substantially the same at each position in the axial direction (even when the axial position is changed). In the present embodiment, the outer diameter φ of the third outer diameter portion 13 13 is equal to the outer diameter φ of the first outer diameter portion 11 11 .

[0019] As shown in FIG. 3, on the outer peripheral surface of the third outer diameter portion 13, an incomplete thread portion 13a and a male thread portion 13b are formed in order from the base end portion (upper end portion) side to the tip end portion (lower end portion) side.

[0020] The incomplete thread portion 13a is a portion where threads and valleys are incompletely formed in a region adjacent to the second outer diameter portion 12. In the present embodiment, the incomplete thread portion 13a has a cylindrical shape with a constant outer diameter (outer diameter φ 13 ) in the axial direction. In other words, the shape of the cross section orthogonal to the axis of the incomplete thread portion 13a is the same at each position in the axial direction (even when the axial position is changed).

[0021] The male thread portion 13b is a portion that engages with the female thread portion 31b of the holding portion 30A described later.

[0022] As shown in FIGS. 1 and 2, an end face (positioning face) 10a formed at the boundary between the third outer diameter portion 13 and the fourth outer diameter portion 14 is parallel to the end face (tip end face of the ultrasonic probe 10) 14a of the fourth outer diameter portion 14.

[0023] ≪Fourth Outer Diameter Portion≫ The fourth outer diameter portion 14 is a portion that is accommodated and held in the holding portion 30A. The fourth outer diameter portion 14 has an outer diameter φ 14 and an axial dimension L 14 and has a cylindrical shape. That is, the fourth outer diameter portion 14 has the same shape (circular shape) in the axial direction. In other words, the shape of the cross section orthogonal to the axis of the fourth outer diameter portion 14 is the same at each position in the axial direction (even when the axial position is changed). The outer diameter φ of the fourth outer diameter portion 14 14 is equal to the outer diameter φ of the third outer diameter portion 1313 is smaller than.

[0024] The end face (the tip end face of the ultrasonic probe 10) 14a of the fourth outer diameter portion 14 is a portion that contacts the ultrasonic propagation portion 20A.

[0025] The end face 10a formed at the boundary between the third outer diameter portion 13 and the fourth outer diameter portion 14 is a positioning surface that is substantially parallel to the end face 14a of the fourth outer diameter portion 14.

[0026] In the ultrasonic probe 10, the tip end side end face 12a, the end face 10a, and the end face 14a are planes that are substantially orthogonal (orthogonal in this embodiment) to the axis of the ultrasonic probe 10, and are substantially parallel to each other (parallel in this embodiment).

[0027] <Ultrasonic propagation member> The ultrasonic propagation member 3A is a resin member having a substantially bottomed cylindrical shape that is attached to the tip end portion (lower end portion) of the ultrasonic probe 10 within the socket. The ultrasonic propagation member 3A fills the gap between the ultrasonic probe 10 and the head portion 2a of the bolt 2, and propagates the ultrasonic pulse oscillated from the ultrasonic probe 10 to the bolt 2, or propagates the echo of the ultrasonic pulse from the bolt 2 to the ultrasonic probe 10. The ultrasonic propagation member 3A according to the first embodiment of the present invention includes an ultrasonic propagation portion 20A and a holding portion 30A.

[0028] <Ultrasonic propagation portion> The ultrasonic propagation portion 20A is a member that propagates an ultrasonic pulse between the ultrasonic probe 10 and the bolt 2. The ultrasonic propagation portion 20A is made of a material that is softer than the holding portion 30A, specifically, a soft material that can be elastically deformed in the axial direction (vertical direction) within the elastic deformation range in a state of being attached to the bolt 2. In this embodiment, it is formed of an elastomer. The ultrasonic propagation portion 20A includes, in order from the base end portion (upper end portion) side on the ultrasonic probe 10 side to the tip end portion (lower end portion) side on the bolt 2 side, a first outer diameter portion 21, a reduced diameter portion 22, and a second outer diameter portion 23, integrally and coaxially.

[0029] ≪First outer diameter portion≫ The first outer diameter portion 21 is a portion to be accommodated in the holding portion 30A. The first outer diameter portion 21 has an outer diameter of φ 21 and an axial dimension L 21 and has a disc shape. That is, the first outer diameter portion 21 is a portion with a constant shape that exhibits the same shape (circular shape) in the axial direction. In other words, the shape of the cross-section perpendicular to the axis of the first outer diameter portion 21 is the same at each position in the axial direction (even when the axial position is changed). The outer diameter φ 21 of the first outer diameter portion 21 is equal to the outer diameter φ 14 of the fourth outer diameter portion 14 of the ultrasonic probe 10.

[0030] The end face (the base end face of the ultrasonic propagation portion 20A) 21a of the first outer diameter portion 21 is a second contact surface that contacts the end face (the tip end face) 14a of the ultrasonic probe 10.

[0031] The tip end side end face 21b of the first outer diameter portion 21 is substantially parallel to the end face 21a.

[0032] ≪Reduced diameter portion≫ The reduced diameter portion 22 is a portion to be accommodated in the holding portion 30A. The reduced diameter portion 22 is a conical portion having a tapered shape (conical shape) that tapers from the base end portion (upper end portion) side on the ultrasonic probe 10 side to the tip end portion (lower end portion) side on the bolt 2 side with an axial dimension L 22 . The outer diameter of the base end portion of the reduced diameter portion 22 is smaller than the outer diameter φ 21 of the first outer diameter portion 21.

[0033] ≪Second outer diameter portion≫ The second outer diameter portion 23 is a portion where the base end portion side is accommodated in the holding portion 30A and the tip end portion side is exposed from the holding portion 30A. The second outer diameter portion 23 has an outer diameter of φ 23 and an axial dimension L 23 and has a cylindrical shape. That is, the second outer diameter portion 23 exhibits the same shape (circular shape) in the axial direction. In other words, the shape of the cross-section perpendicular to the axis of the second outer diameter portion 23 is the same at each position in the axial direction (even when the axial position is changed). The outer diameter φ 23 of the second outer diameter portion 23 is equal to the outer diameter of the tip end portion of the reduced diameter portion 22 and the inner diameter φ2 of the concave portion 2b of the bolt 2.

[0034] The end face (the tip face of the ultrasonic propagation part 20A) 23a of the second outer diameter part 23 is a first contact face that contacts the bottom face 2b1 of the recess 2b formed in the head 2a of the bolt 2. The outer peripheral face 23b of the tip part of the second outer diameter part 23 is a fourth contact face that contacts the inner peripheral face 2b2 of the recess 2b.

[0035] In the ultrasonic propagation part 20A, the end face 21a, the tip part side end face 21b, and the end face 23a are each a plane that is substantially orthogonal (orthogonal in this embodiment) to the axis of the ultrasonic propagation part 20A, and are substantially parallel (parallel in this embodiment) to each other.

[0036] ≪Shape of ultrasonic propagation part≫ As shown in FIG. 4, the end face (the first contact face) 23a is smaller than the end face (the tip face) 14a of the ultrasonic probe 10 in an axial view. Specifically, the end face 23a is within the range of the tip face 14a in an axial view.

[0037] The end face (the first contact face) 23a is the same size as the bottom face 2b1 of the recess 2b of the bolt 2b in a state where the bolt 2b is not attached, or is slightly smaller than the bottom face 2b1 of the recess 2b in an axial view. When the end face 23a is slightly smaller than the bottom face 2b1 of the recess 2b, the second outer diameter part 23a bulges outward in the radial direction along with the axial compression deformation due to the attachment to the bolt 2b, and contacts the inner peripheral face 2b2 of the recess 2b.

[0038] The end face (the first contact face) 23a is smaller than the end face (the second contact face) 21a in an axial view. Specifically, the end face 23a is within the range of the end face 21a in an axial view.

[0039] The end face (the second contact face) 21a is the same size as the end face (the tip face) 14a of the ultrasonic probe 10, or is larger than the end face 14a in an axial view.

[0040] As shown in FIG. 2, the cross-sectional area orthogonal to the axial direction of the ultrasonic propagation unit 20A monotonically decreases from the end face (second contact surface) 21a toward the end face (first contact surface) 23a. That is, such a cross-sectional area is constant or decreasing from the end face 21a toward the end face 23a, and does not increase.

[0041] Axial dimension L which is the thickness of the first outer diameter portion 21 21 is 1 / 12 or more of the outer diameter φ of the end face (second contact surface) 21a. 21

[0042] Further, the conical shape of the reduced diameter portion 22 is preferably configured such that when the conical shape is extended toward the base end portion side, the lower end portion of the third outer diameter portion 13 of the ultrasonic probe 10 fits into the extended portion at the same axial position. Furthermore, the conical shape of the reduced diameter portion 22 is more preferably configured such that when the conical shape is extended toward the base end portion side, the lower end portion of the fourth outer diameter portion 14 of the ultrasonic probe 10 fits into the extended portion at the same axial position. According to such a configuration, the ultrasonic wave reflected by the bolt 2 can be suitably propagated to the ultrasonic probe 10.

[0043] <Holding portion> The holding portion 30A is a member that holds the ultrasonic propagation unit 20A with respect to the ultrasonic probe 10. The holding portion 30A is made of a material harder than the ultrasonic propagation unit 20A, specifically, a hard material capable of performing positioning with respect to the bolt 2 in a state of being attached to the bolt 2. In the present embodiment, it is formed of polypropylene. Note that the material of the holding portion 30A is not limited to polypropylene, and any material may be used as long as it is harder than the ultrasonic propagation unit 20A (has a large hardness) and can realize functions such as holding the ultrasonic propagation unit 20A, being fixed to the ultrasonic probe 10, and being positioned with respect to the concave portion 2b of the bolt 2. The holding portion 30A integrally includes a first inner diameter portion 31, a second inner diameter portion (positioning portion) 32, a reduced diameter portion 33, a third inner diameter portion 34, and a fourth inner diameter portion 35 in order from the base end portion side to the tip end portion side.

[0044] ≪First inner diameter portion≫​ The first inner diameter portion 31 is a portion where the third outer diameter portion 13 of the ultrasonic probe 10 is accommodated. The first inner diameter portion 31 has an inner diameter of φ 31 and an axial dimension L 31 and exhibits a cylindrical shape. The inner diameter φ of the first inner diameter portion 31 31 is equal to the outer diameter φ of the third outer diameter portion 13 of the ultrasonic probe 10 13 .

[0045] The end face (the base end face of the holding portion 30A) 31a of the first inner diameter portion 31 is a flange contact surface that contacts the tip end side end face 12a in the flange portion of the ultrasonic probe 10. The axial dimension L31 of the first inner diameter portion 31 is equal to the axial dimension L 13 of the third outer diameter portion 13 of the ultrasonic probe 10

[0046] As shown in FIG. 3, a female screw portion 31b, which is an example of a fixing portion fixed to the outer peripheral surface of the ultrasonic probe 10, is formed on the inner peripheral surface of the first inner diameter portion 31. The tip end side of the female screw portion 31b is a portion where the incomplete screw portion 13a of the ultrasonic probe 10 is press-fitted. The base end side of the female screw portion 31b is a portion that engages with the male screw portion 13b of the ultrasonic probe 10

[0047] Of the female screw portion 31b, the portion corresponding to the incomplete screw portion 13a may have a shape having an inner diameter that is the same as the outer diameter of the incomplete screw portion 13a or an inner diameter that is smaller than the outer diameter of the incomplete screw portion 13a

[0048] As shown in FIGS. 1 and 2, the end face 30a formed at the boundary between the first inner diameter portion 31 and the second inner diameter portion 32 is substantially parallel to the end face (the third contact surface) 35a of the fourth inner diameter portion 35

[0049] ≪Second Inner Diameter Portion≫ The second inner diameter portion 32 is a positioning portion that accommodates the fourth outer diameter portion 14 of the ultrasonic probe 10 and the first outer diameter portion 21 of the ultrasonic propagation portion 20A, and positions the outer peripheral surface of the fourth outer diameter portion 14. The second inner diameter portion 32 has an inner diameter of φ 32 and an axial dimension L 32 and exhibits a cylindrical shape. The inner diameter φ of the second inner diameter portion 3232 is equal to the outer diameter φ of the fourth outer diameter portion 14 of the ultrasonic probe 10 14 and the outer diameter φ of the first outer diameter portion 21 of the ultrasonic propagation portion 20A 21 is equal.

[0050] The axial dimension L of the second inner diameter portion 32 32 is the axial dimension L of the fourth outer diameter portion of the ultrasonic probe 10 14 and the axial dimension L of the first outer diameter portion 21 of the ultrasonic propagation portion 20A 14 is equal to the sum. Also, the axial dimension L of the second inner diameter portion 32 21 is more than twice the axial dimension L of the first outer diameter portion 21 of the ultrasonic propagation portion 20A 32 is. 21 is two times or more.

[0051] In addition, when the axial dimension L 32 is slightly smaller than the sum of the axial dimension L 14 and the axial dimension L 21 , the inner diameter φ 32 may be configured to be equal to the outer diameter φ 14 and slightly larger than the outer diameter φ 21 . In this case, the first outer diameter portion 21 bulges radially outward with the axial compressive deformation and contacts the second inner diameter portion 32.

[0052] The end face 30b formed at the boundary between the second inner diameter portion 32 and the reduced diameter portion 33 is parallel to the end face (third contact surface) 35a of the fourth inner diameter portion 35.

[0053] The inner peripheral surface (and the end face 30b) of the second inner diameter portion 32 is a positioning portion that contacts the end face (positioning surface) 10a of the ultrasonic probe 10 and the outer peripheral surface of the fourth outer diameter portion (small diameter portion) 14 to position these. The inner peripheral surface of the second inner diameter portion 32 positions a part or all of the axial direction of the outer peripheral surface of the fourth outer diameter portion 14 of the ultrasonic probe 10.

[0054] ≪Reduced diameter portion≫ The reduced-diameter portion 33 is a portion where the reduced-diameter portion 22 of the ultrasonic propagation portion 20A is accommodated. The inner peripheral surface of the reduced-diameter portion 33 exhibits a tapered shape (conical shape) that reduces in diameter from the base end portion (upper end portion) side, which is the side of the ultrasonic probe 10, toward the tip end portion (lower end portion) side, which is the side of the bolt 2. The inner diameter of the base end portion of the reduced-diameter portion 33 is smaller than the inner diameter φ 32 and is equal to the inner diameter of the base end portion of the reduced-diameter portion 22 of the ultrasonic propagation portion 20A.

[0055] The axial dimension L 33 of the reduced-diameter portion 33 is equal to the axial dimension L 22 of the reduced-diameter portion 22 of the ultrasonic propagation portion 20A.

[0056] ≪Third inner diameter portion≫ The third inner diameter portion 34 is a portion where the base end portion of the second outer diameter portion 23 of the ultrasonic propagation portion 20A is accommodated. The third inner diameter portion 34 has an inner diameter φ 34 and an axial dimension L 34 and exhibits a cylindrical shape. The inner diameter φ 34 of the third inner diameter portion 34 is equal to the inner diameter of the tip end portion of the reduced-diameter portion 33 and the outer diameter φ 23 of the second outer diameter portion 23 of the ultrasonic propagation portion 20A.

[0057] ≪Fourth inner diameter portion≫ The fourth inner diameter portion 35 is a portion where the axial intermediate portion of the second outer diameter portion 23 of the ultrasonic propagation portion 20A is accommodated. The fourth inner diameter portion 35 has an inner diameter φ 35 and an axial dimension L 35 and exhibits a cylindrical shape. The inner diameter φ 35 of the fourth inner diameter portion 35 is larger than the outer diameter φ 23 of the second outer diameter portion 23 of the ultrasonic propagation portion 20A.

[0058] The end face (the end face of the ultrasonic propagation portion 30A) 35a of the fourth inner diameter portion 35 is the third contact surface that contacts the end face of the head portion 2a of the bolt 2. The outer diameter φ 30 of the fourth inner diameter portion 35 (end face 35a) is smaller than the outer diameter φ 21 of the first outer diameter portion 21 (end face 21a) of the ultrasonic propagation portion 20A.

[0059] In the holding portion 30A, the end face 31a, the end face 30a, the end face 30b, and the end face 35a are planes that are substantially orthogonal (orthogonal in this embodiment) to the axis of the holding portion 30A, and are substantially parallel (parallel in this embodiment) to each other.

[0060] Also, the axial dimension L of the second outer diameter portion 23 of the ultrasonic propagation portion 20A 23 is the axial dimension L of the third inner diameter portion 34 34 , the axial dimension L of the fourth inner diameter portion 35 35 , and the recess 2bo of the bolt 2 is larger than the sum of the axial dimensions L2.

[0061] <Assembly method of ultrasonic propagation portion and holding portion> The ultrasonic propagation portion 20A is assembled to the holding portion 30A by being inserted into the holding portion 30A from above or by being integrally molded (simultaneously molded) in such a state. In the assembled state, the outer peripheral surface of the first outer diameter portion 21 and the end face 21b on the base end portion side of the first outer diameter portion 21 are in contact with the inner peripheral surface and the end face 30b of the second inner diameter portion 32, respectively. Also, the outer peripheral surface of the reduced diameter portion 22 is in contact with the inner peripheral surface of the reduced diameter portion 33. Further, the outer peripheral surface of the base end portion of the second outer diameter portion 23 is in contact with the inner peripheral surface of the third inner diameter portion 34. Also, the end face 23a of the second outer diameter portion 23 is located below (on the bolt 2 side) the end face 35a of the fourth inner diameter portion 35.

[0062] <Assembly method of ultrasonic propagation member and ultrasonic probe> The ultrasonic propagation member 3A is fixed to the ultrasonic probe 10 by screwing a female screw portion 31b formed on the inner peripheral surface of the first inner diameter portion 31 onto a male screw portion 13b formed on the outer peripheral surface of the third outer diameter portion 13 of the ultrasonic probe 10, and press-fitting an incomplete screw portion 13a on the outer peripheral surface of the third outer diameter portion 13. In the assembled state, the tip-side end surface 12a of the second outer diameter portion 12 of the ultrasonic probe 10 contacts the end surface 31a of the first inner diameter portion 31 of the holding portion 30A. Also, the end surface 10a of the ultrasonic probe 10 contacts the end surface 30a of the holding portion 30A. Further, the outer peripheral surface of the fourth outer diameter portion 14 of the ultrasonic probe 10 contacts the inner peripheral surface of the second inner diameter portion 32 of the holding portion 30A. Also, the end surface 14a of the fourth outer diameter portion 14 of the ultrasonic probe 10 contacts the end surface 21a of the first outer diameter portion 21 of the ultrasonic propagation member 20A. By these contacts, the ultrasonic probe 10 and the ultrasonic propagation member 3A are positioned relative to each other.

[0063] <Method of attaching to the bolt> The socket is externally fitted onto the head portion 2a of the bolt 2. Here, the ultrasonic propagation member 3A is attached to the bolt 2 by inserting the tip portion of the second outer diameter portion 23 of the ultrasonic propagation member 20A into a recess 2b formed in the head portion 2a of the bolt 2. In the attached state, the outer peripheral surface of the second outer diameter portion 23 contacts the inner peripheral surface 2b2 of the recess 2b. Thereby, positioning in the direction orthogonal to the axis of the ultrasonic propagation member 3A and the ultrasonic probe 10 is preferably performed. Also, the end surface 23a of the second outer diameter portion 23 of the ultrasonic propagation member 20A contacts the bottom surface 2b1 of the recess 2b of the bolt 2, and the end surface 35a of the fourth inner diameter portion 35 of the holding portion 30A contacts the end surface of the head portion 2a of the bolt 2. Here, the ultrasonic propagation member 20A (mainly the second outer diameter portion 23) is compressed and deformed in the axial direction. A clearance for the compression deformation of the second outer diameter portion 23 is ensured on the inner peripheral surface side of the fourth inner diameter portion 35 of the holding portion 30A.

[0064] In such a state, a control unit (not shown) drives a drive unit (such as a motor, not shown) to rotate the rotary shaft and the socket around the axis. As a result, the bolt 2 is screwed into a hole (not shown) and tightened. Here, the control unit (not shown) oscillates ultrasonic pulses by driving the ultrasonic probe 10. The ultrasonic pulses are propagated to the bolt 2 via the ultrasonic propagation unit 20A. The ultrasonic probe 10 receives echoes from the head 2a (the bottom surface of the concave portion 2b) of the bolt 2 and the tip surface (lower surface) of the shaft portion of the bolt 2, and outputs the received results to the control unit (not shown). The control unit (not shown) calculates the bolt axial force based on such received results.

[0065] The ultrasonic propagation member 3A according to the first embodiment of the present invention includes an ultrasonic propagation unit 20A having a first contact surface (end surface 23a) that contacts the measurement object (bolt 2) and a second contact surface (end surface 21a) that is provided on the opposite side of the first contact surface and contacts the tip surface (end surface 14a) of the ultrasonic probe 10, and a holding unit 30A that holds the ultrasonic propagation unit 20A and has a third contact surface (end surface 35a) that contacts the measurement object on the radially outer side of the first contact surface. The first contact surface is smaller than the tip surface. Therefore, the ultrasonic propagation member 3A can suitably measure a small measurement object, more specifically, a measurement object whose contact portion with the ultrasonic propagation member 3A is smaller than the tip surface of the ultrasonic probe 10 in an axial view.

[0066] In the ultrasonic propagation member 3A, the second contact surface is the same size as the tip surface or larger than the tip surface. Therefore, the ultrasonic propagation member 3A can stabilize the contact portion between the ultrasonic probe 10 and the ultrasonic propagation unit 20A and suitably propagate ultrasonic waves.

[0067] In the ultrasonic propagation member 3A, the second contact surface is larger than the first contact surface. Therefore, the ultrasonic propagation member 3A can suitably measure a measurement object that is smaller than the ultrasonic probe 10 (the contact portion with the ultrasonic propagation member 3A is small).

[0068] In the ultrasonic propagation member 3A, the second contact surface is substantially parallel to the first contact surface, and the cross-sectional area of the ultrasonic propagation part 20A monotonically decreases from the second contact surface toward the first contact surface. Therefore, the ultrasonic propagation member 3A can suitably measure a small measurement object, more specifically, a measurement object whose contact portion with the ultrasonic propagation member 3A is smaller than the tip surface of the ultrasonic probe 10 in the axial view. At the same time, unnecessary portions for ultrasonic propagation in the shape of the ultrasonic propagation part 20A can be reduced, and weight reduction and cost reduction can be achieved.

[0069] In the ultrasonic propagation member 3A, the ultrasonic propagation part 20A has a conical part (diameter-reducing part 22) whose diameter decreases from the second contact surface side toward the first contact surface side. Therefore, the ultrasonic propagation member 3A can suppress the influence of waveform disturbance due to reflection on the outer peripheral surface of the ultrasonic propagation part 20A of the ultrasonic wave propagating through the ultrasonic propagation part 20A.

[0070] In the ultrasonic propagation member 3A, the ultrasonic propagation part 20A has a constant-shape part (first outer diameter part 21) having the same shape from the second contact surface side end toward the first contact surface side, and the thickness of the constant-shape part is 1 / 12 or more of the diameter of the second contact surface. The holding part 30A contacts an end surface (tip-side end surface 21b) on the first contact surface side in the constant-shape part. Therefore, the ultrasonic propagation member 3A can suitably ensure the contact property (adhesion) between the ultrasonic probe 10 and the ultrasonic propagation part 20A by ensuring the thickness of the ultrasonic propagation part 20A between the ultrasonic probe 10 and the holding part 30A.

[0071] In the ultrasonic propagation member 3A, the outer diameter of the third contact surface is smaller than the diameter of the second contact surface. Therefore, the ultrasonic propagation member 3A can be suitably positioned with respect to a small measurement object, more specifically, a measurement object whose contact portion with the ultrasonic propagation member 3A is smaller than the tip surface of the ultrasonic probe 10 in the axial view.

[0072] In the ultrasonic propagation member 3A, the ultrasonic propagation portion 20A is softer than the holding portion 30A. Therefore, since the ultrasonic propagation portion 20A of the ultrasonic propagation member 3A is softer than the holding portion 30A, the amount of compressive deformation of the ultrasonic propagation portion 20A can be suitably set by the third contact surface of the holding portion 30A, and the durability of the ultrasonic propagation portion 20A can be improved while ensuring the measurement performance.

[0073] In the ultrasonic propagation member 3A, in a state before being attached to the measurement object, the first contact surface is located closer to the measurement object side than the third contact surface. Therefore, the ultrasonic propagation member 3A can suitably set the amount of compressive deformation of the ultrasonic propagation portion 20A by the protruding amount of the first contact surface with respect to the third contact surface, and can improve the durability of the ultrasonic propagation portion 20A while ensuring the measurement performance.

[0074] In the ultrasonic propagation member 3A, the holding portion 30A includes a fixing portion fixed to the outer peripheral surface of the ultrasonic probe 10. Therefore, since the ultrasonic propagation member 3A is fixed to the ultrasonic probe 10 in the holding portion 30A that is harder than the ultrasonic propagation portion 20A, the fixity with respect to the ultrasonic probe 10 can be improved, and accurate measurement can be supported.

[0075] In the ultrasonic propagation member 3A, the fixing portion is a female screw portion 31b that is screwed into a male screw portion 13b formed on the outer peripheral surface of the ultrasonic probe 10. Therefore, since the holding portion 30A of the ultrasonic propagation member 3A is fixed to the ultrasonic probe 10 by screw engagement, the fixity with respect to the ultrasonic probe 10 can be further improved, and more accurate measurement can be supported.

[0076] In the ultrasonic propagation member 3A, the first contact surface contacts the bottom surface 2b1 of the recess 2b formed in the object to be measured, and the third contact surface contacts the end surface 2a1 formed outside the recess 2b. Therefore, the ultrasonic propagation member 3A can improve the positioning and fixing properties with respect to the object to be measured and assist in accurate measurement.

[0077] In the ultrasonic propagation member 3A, the ultrasonic propagation portion 20A is formed of an elastomer. Therefore, the ultrasonic propagation member 3A can improve the adhesion to the object to be measured and the ultrasonic probe 10 and assist in accurate measurement.

[0078] In the ultrasonic propagation member 3A, the holding portion 30A is formed of polypropylene. Therefore, since the holding portion 30A of the ultrasonic propagation member 3A is made of polypropylene which is harder than the ultrasonic propagation portion 2A, excessive compression of the ultrasonic propagation portion 20A can be suppressed and the load can be set within a suitable range.

[0079] Further, the ultrasonic measurement structure 1A according to the first embodiment of the present invention includes the ultrasonic propagation member 3A and the ultrasonic probe 10. The ultrasonic probe 10 includes a small-diameter portion (fourth outer diameter portion 24) that constitutes the tip surface side of the ultrasonic probe 10 and a large-diameter portion (third outer diameter portion 23) that constitutes the base end portion side of the ultrasonic probe. The holding portion 30A includes a positioning portion (second inner diameter portion 32) that positions the outer peripheral surface of the small-diameter portion. Therefore, the ultrasonic measurement structure 1A can be suitably positioned in a direction orthogonal to the axis and a direction inclined with respect to the axis of the ultrasonic probe 10 and the ultrasonic propagation member 3A.

[0080] In the ultrasonic measurement structure 1A, the ultrasonic propagation part 20A has a constant-shape part (first outer diameter part) having the same shape extending from the second contact surface side end part toward the first contact surface side, the positioning part positions the outer peripheral surface of the constant-shape part, and the axial dimension of the positioning part is not less than twice the thickness of the constant-shape part. Therefore, the ultrasonic measurement structure 1A can be more suitably positioned in the direction orthogonal to the axis and the direction inclined with respect to the axis of the ultrasonic probe 10 and the ultrasonic propagation member 3A.

[0081] In the ultrasonic measurement structure 1A, the ultrasonic probe 10 has a positioning surface (end surface 10a) substantially parallel to the tip surface at the boundary between the small-diameter part and the large-diameter part, the positioning part of the holding part 30A has an end surface 30a substantially parallel to the third contact surface, and the positioning surface contacts the end surface 30a. Therefore, the ultrasonic measurement structure 1A can be more suitably positioned in the axial direction and the direction inclined with respect to the axis of the ultrasonic probe 10 and the ultrasonic propagation member 3A.

[0082] In the ultrasonic measurement structure 1A, a male screw part 13b is formed on the outer peripheral surface of the large-diameter part, a female screw part 31b that engages with the male screw part 13b is formed on the inner peripheral surface of the holding part 30A, the ultrasonic probe 10 has a flange part (second outer diameter part 12) formed on the base end part side of the male screw part 13b, and the holding part 30A has a flange contact surface (end surface 31a) that contacts the surface (tip end part side end surface 12a) on the measurement object side at the flange part. Therefore, the ultrasonic measurement structure 1A can improve the positioning property and fixing property with respect to the measurement object and support accurate measurement. Further, the ultrasonic measurement structure 1A can realize easy replacement of the ultrasonic propagation member 3A with respect to the ultrasonic probe 10. Further, the ultrasonic measurement structure 1A can suitably set the screwing amount of the male screw part 13b and the female screw part 31b and can suitably set the distance from the ultrasonic probe 10 to the first contact surface and the third contact surface.

[0083] In the ultrasonic measurement structure 1A, the ultrasonic probe 10 has an incomplete thread portion 13a between the male thread portion 13b and the flange portion, and a portion corresponding to the incomplete thread portion 13a in the holding portion 30A has an inner diameter that is the same as the outer diameter of the incomplete thread portion 13a or an inner diameter that is smaller than the outer diameter of the incomplete thread portion 13a. Therefore, the ultrasonic measurement structure 1A can further improve the fixing property of the ultrasonic probe 10 and the ultrasonic propagation member 3A by the press-fitting state in the incomplete thread portion 13a, and realize more stable measurement.

[0084] <Second Embodiment> Subsequently, the tightening device according to the second embodiment of the present invention will be described focusing on the differences from the tightening device 1A according to the first embodiment.

[0085] As shown in FIGS. 6 and 7, the tightening device 1B according to the second embodiment of the present invention includes an ultrasonic propagation member 3B instead of the ultrasonic propagation member 3A. The ultrasonic propagation member 3B includes an ultrasonic propagation part 20B and a holding part 30B instead of the ultrasonic propagation part 20A and the holding part 30A.

[0086] <Ultrasonic Propagation Part> As shown in FIGS. 8 and 9, the ultrasonic propagation part 20B includes, in order from the base end part side to the tip end part side, a first outer diameter part 21 and a second outer diameter part 23, which are provided integrally and coaxially. Further, the ultrasonic propagation part 20B integrally includes a plurality of sets of extended parts 24 and protruding parts 25 that are provided at equal intervals in the circumferential direction.

[0087] ≪Extended Part≫ The extended part 24 is a part that extends radially outward from the radially outer end part of the base end part of the second outer diameter part 23.

[0088] ≪Protruding Part≫ The protruding part 25 is a part that extends upward from the radially outer end part of the extended part 24.

[0089] <Holding Part> The holding part 30B integrally and coaxially includes a first inner diameter part 31, a second inner diameter part 32, a third inner diameter part 34, and a fourth inner diameter part 35 in order from the base end part side to the tip end part side. In the present embodiment, the inner diameter of the fourth inner diameter part 35 is equal to the inner diameter of the third inner diameter part 34 and the outer diameter of the second outer diameter part 23 of the ultrasonic propagation part 20.

[0090] In the second inner diameter part 32, the third inner diameter part 34, and the fourth inner diameter part 35, a groove part 30c in which the extending part 24 is accommodated is formed. The fourth inner diameter part 35 is divided in the circumferential direction by the groove part 30c. In the first inner diameter part 31 and the second inner diameter part 32, a hole part 30d in which the protruding part 25 is accommodated is formed.

[0091] The ultrasonic propagation member 3B according to the second embodiment of the present invention can suitably secure the ultrasonic propagation path by a plurality of extending parts 24 in the circumferential direction.

[0092] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and can be appropriately modified without departing from the gist of the present invention. For example, the first contact surface may be smaller than the tip end surface of the ultrasonic probe 20 and smaller than the second contact surface, and the second contact surface may be smaller than the linear end surface of the ultrasonic probe 20.

Explanation of reference numerals

[0093] 1A, 1B Tightening device (bolt axial force measuring device) 2 Bolt (object to be measured) 2a Head 2a1 End face 2b Recess 2b1 Bottom face 2b2 Inner peripheral surface 3A, 3B Ultrasonic propagation member 10 Ultrasonic probe 10a End face (positioning face) 12 Second outer diameter part (flange part) 12a Tip end part side end face (end face) 13 Third outer diameter part (large diameter part) 13a Incomplete thread part 13b Male screw part 14 Fourth outer diameter part (small diameter part) 14a End face (tip end face) 20A, 20B Ultrasonic propagation part 21 First outer diameter part (constant shape part) 21a End face (second contact surface) 21b Base end side end face (end face) 22 Reduced diameter part (conical shape part) 23a End face (first contact surface) 30A, 30B Holding part 30a End face 31a End face (flange contact surface) 31b Female screw part (fixing part) 32 Second inner diameter part (positioning part) 35a End face (third contact surface)

Claims

1. An ultrasonic propagation unit having a first contact surface that contacts an object to be measured and a second contact surface that is provided on the opposite side of the first contact surface and contacts the tip surface of an ultrasonic probe; A holding unit that holds the ultrasonic propagation unit and has a third contact surface that contacts the object to be measured on the radially outer side of the first contact surface; comprising: The first contact surface is smaller than the tip surface, The ultrasonic propagation unit has a constant-shape portion having the same shape from the second contact surface toward the first contact surface at an end portion on the second contact surface side in the ultrasonic propagation unit, The thickness of the constant-shape portion is 1 / 12 or more of the diameter of the second contact surface, The holding unit contacts an end surface on the first contact surface side in the constant-shape portion An ultrasonic propagation member, characterized in that.

2. The second contact surface is the same size as the tip surface or larger than the tip surface The ultrasonic propagation member according to claim 1, characterized in that.

3. The second contact surface is larger than the first contact surface The ultrasonic propagation member according to claim 1, characterized in that.

4. The second contact surface is substantially parallel to the first contact surface, The cross-sectional area of the ultrasonic propagation unit monotonically decreases from the second contact surface toward the first contact surface The ultrasonic propagation member according to claim 3, characterized in that.

5. The ultrasonic propagation unit has a conical portion that tapers from the second contact surface side toward the first contact surface side The ultrasonic propagation member according to claim 4, characterized in that.

6. The outer diameter of the third contact surface is smaller than the diameter of the second contact surface The ultrasonic propagation member according to claim 1, characterized in that...

7. The ultrasonic propagation part is softer than the holding part The ultrasonic propagation member according to claim 1, characterized in that...

8. In the state before being attached to the measurement object, the first contact surface is located closer to the measurement object side than the third contact surface The ultrasonic propagation member according to claim 7, characterized in that...

9. The holding part includes a fixing part fixed to the outer peripheral surface of the ultrasonic probe The ultrasonic propagation member according to claim 7, characterized in that...

10. The fixing part is a female screw part that screws into a male screw part formed on the outer peripheral surface of the ultrasonic probe The ultrasonic propagation member according to claim 9, characterized in that...

11. The first contact surface contacts the bottom surface of a recess formed in the measurement object, The third contact surface contacts an end surface formed outside the recess The ultrasonic propagation member according to claim 7, characterized in that...

12. The ultrasonic propagation part is formed of an elastomer The ultrasonic propagation member according to claim 7, characterized in that...

13. The holding part is formed of polypropylene The ultrasonic propagation member according to claim 12, characterized in that...

14. The ultrasonic propagation member according to any one of claims 1 to 13, and The ultrasonic probe, and Comprising The ultrasonic probe is A small-diameter part constituting the tip surface side of the ultrasonic probe, and The large-diameter portion constituting the proximal end portion side of the ultrasonic probe, is provided with, The holding portion includes a positioning portion that positions the outer peripheral surface of the small-diameter portion. An ultrasonic measurement structure characterized by this.

15. The ultrasonic propagation portion has a shape-constant portion having the same shape from the second contact surface toward the first contact surface side at the end portion on the second contact surface side in the ultrasonic propagation portion. The positioning portion positions the outer peripheral surface of the shape-constant portion. The axial dimension of the positioning portion is not less than twice the thickness of the shape-constant portion. The ultrasonic measurement structure according to claim 14, characterized by this.

16. The ultrasonic probe has a positioning surface substantially parallel to the front end surface at the boundary between the small-diameter portion and the large-diameter portion. The positioning portion of the holding portion has an end surface substantially parallel to the third contact surface. The positioning surface contacts the end surface. The ultrasonic measurement structure according to claim 14, characterized by this.

17. A male screw portion is formed on the outer peripheral surface of the large-diameter portion. A female screw portion that engages with the male screw portion is formed on the inner peripheral surface of the holding portion. The ultrasonic probe has a flange portion formed on the proximal end portion side of the male screw portion. The holding portion has a flange contact surface that contacts the surface on the measurement object side in the flange portion. The ultrasonic measurement structure according to claim 16, characterized by this.

18. The ultrasonic probe has an incomplete screw portion between the male screw portion and the flange portion. The portion corresponding to the incomplete screw portion in the holding portion has a portion having an inner diameter equal to the outer diameter of the incomplete screw portion or an inner diameter smaller than the outer diameter of the incomplete screw portion. The ultrasonic measurement structure according to claim 17, characterized by the above.

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