Screw hole inspection device and screw tightening device

Abstract

To disclose at least one example of a screw hole inspection device capable of accurately inspecting the integrity of a screw hole.SOLUTION: A flexible joint 5 is a joint capable of transmitting rotational force to an inspection bolt Is even when the attitude of the inspection bolt Is changes in any of the first direction D1, second direction D2, third direction D3, and fourth direction D4. Accordingly, even when the central axis of the inspection bolt Is is misaligned with the central axis of the screw hole Sh, a screw hole inspection device can properly insert and screw the inspection bolt Is into the screw hole Sh, and can accurately inspect the integrity of the screw hole Sh.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a screw hole inspection device and a screw tightening device.

Background Art

[0002] For example, in the screw hole inspection device according to Patent Document 1, the soundness of the screw hole is inspected by utilizing the change in the axial torque of the inspection bolt.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, if the central axis of the inspection bolt is displaced from the central axis of the screw hole, the inspection bolt cannot be properly inserted and screwed into the screw hole, so that the soundness of the screw hole cannot be accurately inspected. The present disclosure discloses an example of a screw hole inspection device in view of this point.

Means for Solving the Problems

[0005] A screw hole inspection device that inspects whether the screw hole (Sh) is sound by inserting an inspection bolt (Is) into the screw hole (Sh) desirably includes, for example, the following constituent elements.

[0006] That is, the said constituent element includes an electric motor (4) that generates a rotational force for screwing the inspection bolt (Is) into the screw hole (Sh), and a flexible joint (5) provided in the rotational force transmission path (4A) from the output shaft of the electric motor (4) to the inspection bolt (Is). When the central axis (Do) of the output shaft is orthogonal, and two mutually orthogonal directions are defined as the first direction (D1) and the second direction (D2), the rotational direction with the first direction (D1) as the central axis is defined as the third direction, and the rotational direction with the second direction (D2) as the central axis is defined as the fourth direction, the flexible joint (5) can transmit the rotational force to the inspection bolt (Is) even when the posture of the inspection bolt (Is) changes in any one of the first direction (D1), the second direction (D2), the third direction (D3), and the fourth direction (D4).

[0007] Accordingly, in the said screw hole inspection device, even when the central axis of the inspection bolt (Is) and the central axis of the screw hole (Sh) are misaligned, it is possible to appropriately insert and screw the inspection bolt (Is) into the screw hole (Sh), so that the soundness of the screw hole can be accurately inspected.

[0008] Incidentally, the reference numerals in the above brackets are an example showing the correspondence with the specific configuration etc. described in the embodiments to be described later, and the present disclosure is not limited to the specific configuration etc. indicated by the reference numerals in the above brackets.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0010] The following "Embodiments of the Invention" show an example of embodiments belonging to the technical scope of the present disclosure. That is, the invention-specific matters described in the claims are not limited to the specific configurations, structures, etc. shown in the following embodiments.

[0011] Note that the arrows, hatching, etc. indicating directions attached to each figure are described to facilitate understanding of the relationship between the figures and the shape of each member or part. Therefore, the invention disclosed in the present disclosure is not limited to the directions attached to each figure. The figure with hatching does not necessarily show a cross-sectional view.

[0012] At least one member or part described with a reference sign is provided at least one, unless otherwise specified such as "one". That is, when there is no specification such as "one" or "only", two or more of the members may be provided.

[0013] The screw hole inspection measure shown in the present disclosure includes at least one of the components such as the members or parts described with reference signs, and the structural parts shown in the drawings. Furthermore, it does not deny the existence of components other than the components described with reference signs.

[0014] (First Embodiment) <1. Outline of Screw Hole Inspection Device> In this embodiment, the screw hole inspection device according to the present disclosure is applied to a screw hole inspection device for inspecting screw holes provided in a wall or a floor. As shown in FIG. 1, the screw hole inspection device 1 according to this embodiment is a screw hole inspection device for inspecting a large number of screw holes Sh provided in a wall surface W1 orthogonal to the horizontal direction.

[0015] Incidentally, the wall surface W1 is made of concrete. The screw hole Sh is constituted by a metal screw insert Shi (see FIG. 2) embedded in the concrete. The screw insert Shi is a substantially cylindrical member provided with an internal thread on the inner peripheral surface.

[0016] The screw hole inspection device 1 includes at least a determination device 2 and a screw tightening device 3. The determination device 2 is a device that determines whether the screw hole Sh is sound by inserting an inspection bolt Is (see Fig. 2) into the screw hole Sh.

[0017] Specifically, the determination device 2 inserts and rotates an inspection bolt Is into the screw hole Sh to be inspected. Then, when the torque during rotation exceeds a predetermined value, the determination device 2 determines that the screw hole Sh is unsound, and when the torque is less than the predetermined value, the determination device 2 determines that the screw hole Sh is sound.

[0018] The above torque is detected via the torque (for example, the value of the energizing current, etc.) generated by the electric motor 4 (see Fig. 2) that rotates the inspection bolt Is. The electric motor 4 generates a rotational force to screw the inspection bolt Is into the screw hole Sh.

[0019] <2. Screw tightening device> The screw tightening device 3 includes at least the electric motor 4 and the flexible joint 5 shown in Fig. 2, and the robot arm 6 and the control device 7 shown in Fig. 1. A tapered portion Ta having a substantially conical inclined curved surface is provided on the tip side of the inspection bolt Is.

[0020] <2.1 Flexible joint> As shown in Fig. 2, the flexible joint 5 is provided in the rotational force transmission path 4A from the output shaft of the electric motor 4 to the inspection bolt Is.

[0021] The flexible joint 5 is a joint that can transmit rotational force to the inspection bolt Is even when the posture of the inspection bolt Is changes in any one of the first direction D1, the second direction D2, the third direction D3, and the fourth direction D4.

[0022] Note that the first direction D1 and the second direction D2 are two directions that are orthogonal to the central axis Do of the output shaft (hereinafter also referred to as the insertion direction Do) and orthogonal to each other. The third direction D3 refers to the rotational direction with the first direction D1 as the center line. The fourth direction D4 refers to the rotational direction with the second direction D2 as the center line.

[0023] Incidentally, in this embodiment, the insertion direction Do substantially coincides with the direction orthogonal to the wall surface W1, the first direction D1 substantially coincides with the vertical direction, and the second direction D2 substantially coincides with the horizontal direction. Therefore, the third direction D3 coincides with the circumferential direction with the vertical direction as the center line, and the fourth direction D4 coincides with the circumferential direction with the horizontal direction as the center line.

[0024] The flexible joint 5 according to this embodiment is configured to have a plurality (two in this embodiment) of joint portions 5A and 5B. Those two joint portions 5A and 5B are connected in series along the rotational force transmission path 4A.

[0025] And each joint portion 5A, 5B is configured to have a spring portion 5C. Each spring portion 5C is an elastic portion that generates a restoring force to restore the posture to the posture before the change when the posture of the inspection bolt Is changes in any of the first direction D1 to the fourth direction D4. Note that each spring portion 5C according to this embodiment is configured in a coil spring shape.

[0026] <2.2 Robot Arm and Control Unit> The robot arm 6 is a multi-joint robot that supports the electric motor 4 so as to be displaceable in the insertion direction Do and the first direction D1 to the fourth direction D4. Therefore, the robot arm 6 can control the posture of the electric motor 4 so that the central axis Do of the output shaft of the electric motor 4 is parallel to the center line of the screw hole Sh.

[0027] For example, when the robot arm 6 rotates about a vertical axis or a horizontal axis, the central axis Do greatly inclines with respect to the center line of the screw hole Sh, so there is a possibility that the inclination cannot be absorbed and corrected only by the flexible joint 5.

[0028] On the other hand, since the robot arm 6 according to this embodiment can displace the electric motor 4 in the insertion direction Do and the first to fourth directions D1 to D4, it is possible to absorb and correct the inclination of the central axis Do caused by the rotation of the robot arm 6 about the vertical axis or the horizontal axis.

[0029] The control unit 7 controls the operation of the robot arm 6 and, in cooperation with the determination device 2, controls the rotation and stop of the electric motor 4. The control unit 7 is a computer-based controller having a CPU, ROM, RAM, etc. Note that the software for executing the following control is stored in advance in a non-volatile storage device (not shown) such as ROM.

[0030] <Control of the robot arm when inserting the inspection bolt into the screw hole> First, the control unit 7 operates the robot arm 6 so that the inspection bolt Is approaches the screw hole Sh in a state where the center line of the inspection bolt Is is displaced upward with respect to the center line of the screw hole Sh (hereinafter, this operation is referred to as first approach mode control).

[0031] After executing the first approach mode control, the control unit 7 operates the robot arm 6 so that the center line of the inspection bolt Is coincides with the center line of the screw hole Sh as shown in FIG. 3 (hereinafter, this operation is referred to as second approach mode control).

[0032] During the second approach mode control, that is, when the robot arm 6 operates so that the center line of the inspection bolt Is coincides with the center line of the screw hole Sh, the control unit 7 rotates the output shaft of the electric motor 4 in the reverse direction.

[0033] Then, when it becomes a timing at which it is possible to assume that the inspection bolt Is has been inserted into the screw hole Sh, the control unit 7 rotates the output shaft of the electric motor 4 in the forward direction. Note that the forward direction refers to the rotation in the direction in which the inspection bolt Is is screwed into the screw hole Sh. The reverse direction refers to the rotation opposite to the forward direction.

[0034] In addition, in this embodiment, learning is performed in advance for the control unit 7 to "judge whether or not it is possible to consider that the inspection bolt Is has been inserted into the screw hole Sh (hereinafter referred to as the insertion timing)". As a result, the control unit 7 can make such a judgment by itself.

[0035] By the way, even when the attitude of the electric motor 4 is held so that the central axis Do of the output shaft of the electric motor 4 is parallel to the center line of the screw hole Sh, due to the gravity acting on the inspection bolt Is, the tip of the inspection bolt Is is inclined with respect to the center line of the screw hole Sh (see FIG. 4).

[0036] Also, when the angle formed by the center line of the inspection bolt Is and the center line of the screw hole Sh is defined as the deflection angle, the greater the rotational speed of the inspection bolt Is, the greater the deflection angle due to the centrifugal force acting on the inspection bolt Is. That is, the inspection bolt Is swings around due to the centrifugal force.

[0037] <2.3 Details of the operation of the screw hole inspection device> After executing the first approach mode control, the control unit 7 causes the second approach mode control to be executed. At this time, the control unit 7 operates the robot arm 6 so that the contact surface pressure between the tip of the inspection bolt Is and the wall surface W1 becomes a surface pressure within a predetermined range.

[0038] For this reason, by rotating the inspection bolt Is in the reverse rotation direction while the tip of the inspection bolt Is is in contact with the wall surface W1, the inspection bolt Is moves irregularly on the wall surface W1 around the screw hole Sh and finally fits into the screw hole Sh so as to be guided by the tapered portion Ta. Then, when the inspection bolt Is reaches the insertion timing, the control unit 7 rotates the output shaft of the electric motor 4 in the forward rotation direction for a predetermined time (hereinafter referred to as the tightening time).

[0039] At this time, the control unit 7 moves the electric motor 4 in the insertion direction Do according to the screwing state between the inspection bolt Is and the screw hole Sh. Then, when the tightening time has elapsed, the control unit 7 rotates the output shaft of the electric motor 4 in the reverse direction for a predetermined time.

[0040] And, before the tightening time elapses, when the torque exceeds a predetermined value, the determination device 2 determines that the screw hole Sh is defective. On the other hand, when the torque is less than the predetermined value until the tightening time elapses, the determination device 2 determines that the screw hole Sh is sound.

[0041] Incidentally, the inspection result is transmitted to the storage device by wireless communication or wired communication as data in which the inspection result and the screw hole Sh to be inspected are associated. By the way, after the inspection bolt Is and the screw hole Sh are screwed together, the electric motor 4 may be moved in the insertion direction Do by a spring (not shown).

[0042] <3. Features of the Screw Hole Inspection Device According to the Present Embodiment> The flexible joint 5 of the screw tightening device 3 is a joint capable of transmitting a rotational force to the inspection bolt Is even when the posture of the inspection bolt Is changes in any one of the first direction D1, the second direction D2, the third direction D3, and the fourth direction D4.

[0043] Thereby, in the screw hole inspection device 1, even when the central axis of the inspection bolt Is and the central axis of the screw hole Sh are displaced, it is possible to appropriately insert and screw the inspection bolt Is into the screw hole Sh, so that the soundness of the screw hole Sh can be accurately inspected.

[0044] The flexible joint 5 is provided with a spring portion 5C that exerts a restoring force to restore the posture to the posture before the change when the posture of the inspection bolt Is changes in any one of the first direction D1 to the fourth direction D4.

[0045] Accordingly, not only when the inspection bolt Is is stationary, but also when the inspection bolt Is is rotating, an increase in the deflection angle of the inspection bolt Is can be suppressed. Consequently, it may be possible to appropriately insert the inspection bolt Is into the screw hole Sh.

[0046] The flexible joint 5 is configured by connecting a plurality of joint portions 5A and 5B in series along the rotational force transmission path 4A. Thereby, when the central axis line Do of the output shaft of the electric motor 4 is displaced from the center line of the screw hole Sh (hereinafter, this state is referred to as eccentricity), it can be absorbed.

[0047] That is, even when the central axis line Do of the output shaft of the electric motor 4 is parallel to the center line of the screw hole Sh, eccentricity occurs when the central axis line Do is displaced parallel to the center line in the first direction D1 or the second direction D2.

[0048] Since the joint portions 5A and 5B according to the present embodiment are configured to have a coil spring-like spring portion 5C, the deflection angles in the third direction D3 and the fourth direction D4 can be easily absorbed. However, it is difficult for a single spring portion 5C to absorb an eccentricity displaced parallel to the first direction D1 or the second direction D2.

[0049] On the other hand, in the present embodiment, since a plurality of joint portions 5A and 5B are connected in series along the rotational force transmission path 4A, when observing the entire flexible joint 5, it becomes possible to absorb an eccentricity displaced parallel to the first direction D1 or the second direction D2 (see FIG. 5).

[0050] Note that if the axial length of the spring portion 5C is sufficiently long, it becomes possible to absorb an eccentricity displaced parallel to the first direction D1 or the second direction D2 with only one joint portion 5A. However, in such a configuration, there is a possibility that the deflection angle may become large.

[0051] In contrast, in the present embodiment, since the plurality of joint portions 5A and 5B are connected in series along the rotational force transmission path 4A, it is possible to absorb eccentricity without making the axial length of the spring portion 5C sufficiently long.

[0052] The control unit 7 operates the robot arm 6 so that the inspection bolt Is approaches the screw hole Sh in a state where the center line of the inspection bolt Is is shifted upward with respect to the center line of the screw hole Sh. Thereby, it becomes possible to appropriately insert the inspection bolt Is into the screw hole Sh while absorbing the deflection angle due to the gravity acting on the inspection bolt Is.

[0053] That is, after approaching in a state where the center line of the inspection bolt Is is once shifted upward with respect to the center line of the screw hole Sh, the operation of aligning with the center line of the screw hole, in other words, not aligning with the center line of the screw hole Sh from the beginning is because the inspection bolt Is is hanging down due to gravity. If the center line of the inspection bolt Is is immediately aligned with the center line of the screw hole Sh, the inspection bolt Is may come into contact with the lower side of the center line of the screw hole Sh and may not be inserted into the screw hole Sh.

[0054] Therefore, in the present embodiment, the inspection bolt Is that is hanging down is shifted slightly upward with respect to the center line of the screw hole Sh so as to be as close as possible to the screw hole, and then the center line of the inspection bolt Is is lowered to align with the center line of the screw hole.

[0055] (Other Embodiments) Each spring portion 5C according to the above-described embodiment was configured in a coil spring shape. However, the present disclosure is not limited to this. That is, the present disclosure may be configured such that, for example, the flexible joint 5 is configured by a joint portion in which the spring portion 5C is configured by an annular disk.

[0056] The flexible joint 5 according to the above-described embodiment was a flexible joint having a spring portion 5C. However, the present disclosure is not limited thereto. That is, the present disclosure may be, for example, a flexible joint that does not include a spring portion 5C such as a universal joint or a flexible cable.

[0057] In addition, when the screw hole Sh is provided in a horizontal plane such as the floor, the central axis Do of the output shaft of the electric motor 4 substantially coincides with the direction of gravity, so that the posture of the inspection bolt Is is less likely to tilt due to the influence of gravity.

[0058] Therefore, when the screw hole Sh is provided in a horizontal plane such as the floor, a large deflection angle or wobbling is less likely to occur, so that it may be possible to employ a flexible joint that does not include a spring portion 5C.

[0059] The robot arm 6 according to the above-described embodiment was displaceable in the insertion direction Do and the first to fourth directions D1 to D4. However, the present disclosure is not limited thereto. That is, for the present disclosure to be capable of executing, for example, the first approach mode control, it is sufficient if the robot arm 6 is capable of displacing the electric motor 4 at least in the insertion direction Do, the first direction D1, and the second direction D2.

[0060] The robot arm 6 according to the above-described embodiment was of a type in which the joint portion rotates. However, the present disclosure is not limited thereto. That is, the present disclosure may be, for example, a robot arm 6 in which the electric motor 4 is displaceable in parallel in the insertion direction Do, the first direction D1, and the second direction D2.

[0061] According to the robot arm 6, at least the first approach mode control can be executed. And in the robot arm 6, for example, the entire robot arm 6 may be configured to be displaced in the second direction D2 by wheels.

[0062] The bolt tightening device 3 according to the above-described embodiment was a bolt tightening device for tightening the inspection bolt Is into the screw hole Sh. However, the present disclosure is not limited to this. That is, the present disclosure is applicable to, for example, a bolt tightening device for tightening ordinary bolts and screws as well.

[0063] In the above-described embodiment, when the robot arm 6 operates so that the center line of the inspection bolt Is coincides with the center line of the screw hole Sh, the control unit 7 rotates the output shaft of the electric motor 4 in the reverse direction.

[0064] However, the present disclosure is not limited to this. That is, the present disclosure may be configured such that, for example, the output shaft rotates forward when the robot arm 6 operates so that the center line of the inspection bolt Is coincides with the center line of the screw hole Sh.

[0065] The tip of the taper portion Ta of the inspection bolt Is according to the above-described embodiment was flat, which was constituted by a conical surface. However, the present disclosure is not limited to this. That is, the present disclosure may be configured such that, for example, the tip is spherical, conical, or pyramidal, or the taper portion Ta is pyramidal.

[0066] In the above-described embodiment, the control unit 7 was configured to perform learning control in advance to determine whether or not it was the time of insertion. However, the present disclosure is not limited to this. That is, the present disclosure may be configured to have, for example, a camera and determine whether or not it is the time of insertion using an image captured by the camera.

[0067] In the above, the coordinates of the screw hole Sh may be stored in the control unit 7 in advance, and the control unit 7 may determine whether or not it is the time of insertion based on whether or not the tip of the inspection bolt Is has reached the coordinates of the screw hole Sh based on the operation of the robot arm 6.

[0068] Furthermore, the present disclosure only needs to conform to the gist of the disclosure described in the above-described embodiments, and is not limited to the above-described embodiments. Therefore, a configuration in which at least two of the above-described multiple embodiments are combined, or a configuration in which any one of the constituent elements illustrated or described with reference numerals in the above-described embodiments is abolished may also be acceptable.

Description of Reference Numerals

[0069] 1… Screw hole inspection device 2… Judgment device 4… Electric motor 4A… Rotational force transmission path 5… Flexible joint 5A, 5B… Joint part 5C… Spring part 6… Robot arm 7… Control unit

Claims

1. In a screw hole inspection device for inspecting whether a screw hole is sound by inserting an inspection bolt into the screw hole, an electric motor that generates a rotational force for screwing the inspection bolt into the screw hole; a flexible joint provided in a rotational force transmission path from the output shaft of the electric motor to the inspection bolt, when the central axis of the output shaft is orthogonal, and two directions orthogonal to each other are defined as a first direction and a second direction, a rotational direction with the first direction as the center line is defined as a third direction, and a rotational direction with the second direction as the center line is defined as a fourth direction, the flexible joint is a screw hole inspection device capable of transmitting a rotational force to the inspection bolt even when the posture of the inspection bolt changes in any one of the first direction, the second direction, the third direction, and the fourth direction.

2. The flexible joint has a spring portion, furthermore, when the posture of the inspection bolt changes in any one of the first direction, the second direction, the third direction, and the fourth direction, the spring portion can exert a restoring force to restore the posture to the posture before the change. The screw hole inspection device according to claim 1.

3. The flexible joint is configured by connecting a plurality of joint portions in series along the rotational force transmission path, furthermore, each of the plurality of joint portions is configured to have the spring portion. The screw hole inspection device according to claim 2.

4. A conical taper portion is provided on the tip side of the inspection bolt. The screw hole inspection device according to any one of claims 1 to 3.

5. When the direction of the central axis is defined as the insertion direction and the central axis is in the horizontal direction, a robot capable of displacing the electric motor at least in the insertion direction, the first direction, and the second direction, a control unit that controls the operation of the robot, the control unit operates the robot so that the inspection bolt approaches the screw hole in a state where the center line of the inspection bolt is displaced upward with respect to the center line of the screw hole, and then operates the robot so that the center line of the inspection bolt coincides with the center line of the screw hole. The screw hole inspection device according to claim 4.

6. When the rotation in the direction in which the inspection bolt is screwed into the screw hole is defined as the forward rotation direction and the rotation in the direction opposite to the forward rotation direction is defined as the reverse rotation direction, The control unit that controls the rotation of the electric motor rotates the output shaft of the electric motor in the reverse direction when the robot operates so that the center line of the inspection bolt coincides with the center line of the screw hole according to claim 5.

7. In a screw tightening device for inserting and screwing a bolt into a screw hole, an electric motor that generates a rotational force for screwing the bolt into the screw hole; a flexible joint provided in a rotational force transmission path from the output shaft of the electric motor to the bolt, when the center axis of the output shaft is orthogonal, and two directions orthogonal to each other are defined as a first direction and a second direction, the rotational direction with the first direction as the center line is defined as a third direction, and the rotational direction with the second direction as the center line is defined as a fourth direction, the flexible joint is a screw tightening device capable of transmitting a rotational force to the bolt even when the posture of the bolt changes in any one of the first direction, the second direction, the third direction, and the fourth direction.

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