JP7665146B2 - Nutrunner operation device - Google Patents

Description

The present invention relates to a technology that assists in the operation of a nut runner that tightens a bolt when measuring the bolt axial force.

The bolt axial force is measured by using an ultrasonic sensor to measure the length of the bolt while it is being tightened (see Patent Document 1).

JP 2020-19214 A

Such nut runners are held by the user, but because the posture of the nut runner has a large effect on the bolt axial force, it is desirable to appropriately adjust the three-dimensional position and posture of the nut runner.

The present invention was devised in consideration of the above-mentioned issues, and aims to provide a nut runner operating device that can optimally assist in changing the position and posture of a nut runner.

In order to solve the above-mentioned problems, a nut runner operating device of the present invention comprises a nut runner capable of tightening a bolt, and a movable arm supporting a base end side of the nut runner, the nut runner comprising a drive shaft rotatable by a drive unit, an ultrasonic sensor provided at the tip of the drive shaft, and a handle cover exteriorly mounted so as to be rotatable relative to the drive shaft, the handle cover being configured so that a user can change the position of the nut runner supported by the movable arm, and having a switch unit for operating the drive unit, the nut runner comprising a cylindrical first terminal fitted onto the drive shaft and connected to the ultrasonic sensor, and a second terminal capable of slidingly maintaining a connection to the first terminal which rotates together with the drive shaft and connected to a control unit which calculates a bolt axial force based on the detection result of the ultrasonic sensor, the first terminal and the second terminal being provided on the movable arm side of the handle cover, and the handle cover and the second terminal being independently rotatable relative to the drive shaft.

The present invention can effectively assist the user in changing the position and posture of the nut runner, enabling accurate bolt axial force measurement.

1 is a perspective view showing a nut runner operation device according to an embodiment of the present invention; FIG. 1 is a cross-sectional view showing a schematic diagram of a nut runner according to an embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings as appropriate. Identical components are given the same reference numerals, and duplicate descriptions will be omitted.

As shown in FIG. 1, the bolt axial force measuring device 1 according to the embodiment of the present invention is a device that measures the bolt (tightening) axial force generated when a bolt 2 (see FIG. 2) is tightened to a measurement object (e.g., an engine, etc.) by a nut runner 9, and is a nut runner operation device that assists a user in operating the nut runner 9. The bolt axial force measuring device (nut runner operation system) 1 includes a base unit 3 and a vertical arm unit 6 erected from the base unit 3. A measurement object having a female thread is placed on the base unit 3.

The bolt axial force measuring device 1 comprises a plurality of arms 7 connected at one end to a vertical arm 6 and connected in series via a joint 8, and a nut runner (tightening device) 9 held by the arm 7 at the other end. The plurality of arms 7 and the joint 8 form a movable arm that can change the position and posture of the nut runner 9 in three dimensions in response to the movements of a user who operates the nut runner 9. The plurality of arms 7 and the joint 8 maintain the position and posture of the nut runner 9 when the nut runner 9 is not being operated by a user.

In this embodiment, one end of the first arm 7 is attached to the vertical arm 6 so that its position can be changed in the vertical direction and its position can be changed around the vertical axis. One end of the second arm 7 is attached to the other end of the first arm 7 via a joint 8 so that its position can be changed around the vertical axis. One end of the third arm 7 is attached to the other end of the second arm 7 via a joint 8 so that its position can be changed around the vertical axis. One end of the fourth arm 7 is attached to the other end of the third arm 7 via a joint 8 so that its position can be changed around the horizontal axis. One end of the fifth arm 7 is attached to the other end of the fourth arm 7 via a joint 8 so that its position can be changed around the horizontal axis. A cover 60 of the nut runner 9, which will be described later, is attached to the other end of the fifth arm 7.

That is, the movable arm forms a link mechanism having at least two rotation axes by connecting multiple arm sections 7 arranged in series by joint sections 8. Here, the two rotation axes included in the at least two rotation axes are set in different directions. Such a link mechanism allows the nut runner 9 to change its position (and posture) three-dimensionally. In addition, in this embodiment, the fourth pair of upper and lower arm sections 7A and the joint sections 8 and arm sections 7B, 7C at both ends thereof form a parallel crank mechanism that has a parallelogram shape in side view (when viewed from a direction perpendicular to the fastening direction of the bolt 2). Such a parallel crank mechanism allows the nut runner 9 to move while maintaining a posture extending in the vertical direction when the user operates the nut runner 9.

In the bolt axial force measuring device 1, the control unit C drives the drive unit M (motor, etc.) to rotate the nut runner 9 attached to the bolt 2 (see FIG. 2), thereby tightening the bolt 2 against the female thread formed in the measurement object placed on the base unit 3. The control unit C of the bolt axial force measuring device 1 calculates the bolt axial force based on the echo of the ultrasonic pulse when the bolt is tightened. The control unit C can display the calculated bolt axial force on a display device (monitor, etc.) not shown.

<Nutrunner>
The nut runner 9 includes a control unit C and a drive unit M above the portion held by the arm unit 7 on the other end side. The control unit C and the drive unit M are covered by a cover member. The control unit C may be configured separately from other parts of the nut runner 9. As shown in FIG. 2, the nut runner 9 includes a rotating shaft 10, a cylindrical unit 20, a socket 30, a support unit 40, an ultrasonic sensor 50, a cover 60, and a handle cover 70 below the portion held by the arm unit 7 on the other end side. Note that the socket 30 is omitted in FIG. 1. The nut runner 9 also includes a switch terminal 81, a first terminal 82, and a second terminal 83. The nut runner 9 also includes bearings B1, B2, B3, B4, and B5 in this order from the base end side to the tip end side. The nut runner 9 also includes a connector C<b>1 provided on the tip end side of the cover 60 , and a connector C<b>2 provided on the base end side of the cover 60 .

The base end side of the rotating shaft 10 is housed in the cover 60, the axial middle part of the rotating shaft 10 is housed in the handle cover 70, and the tip end side of the rotating shaft 10 is exposed from the cover 60 and the handle cover 70. The switch terminal 81 is provided in the handle cover 70, the first terminal 82 and the second terminal 83 are provided in the cover 60, and the connectors C1 and C2 are provided in the cover 60. That is, the first terminal 82, the second terminal 83, and the connectors C1 and C2 are provided outside the handle cover 70 and on the side of the part supported by the movable arm from the handle cover 70. Note that in FIG. 2, the outer surfaces of a part of the support part 40, the ultrasonic sensor 50, and the bolt 2 are shown, not in cross section.

<Rotating shaft>
The rotating shaft 10 is a metallic tubular member that rotates at a predetermined torque and rotational speed (rotational angular velocity) under the control of the drive unit M by the control unit C. The outer diameter of the portion of the rotating shaft 10 housed in a tubular portion 20 (described later) and the tip end of the shaft 10 exposed from the tubular portion 20 is set to be smaller than the outer diameter of the portion located closer to the base end than the above portions and housed in a cover 60 (described later).

<Cylinder section>
The cylindrical portion 20 is a metal or resin member (collar) that is externally mounted on the tip end side of the rotating shaft 10 so as to be rotatable relative to the rotating shaft 10. The inner diameter of the cylindrical portion 20 is larger than the outer diameter of the rotating shaft 10. The cylindrical portion 20 is attached to the rotating shaft 10 so as to be rotatable relative to the rotating shaft 10 by a bearing B5. The axis (rotation axis) of the cylindrical portion 20 is located on the same straight line as the axis (rotation axis) of the rotating shaft 10. The outer diameter of the cylindrical portion 20 is formed to be smaller than the outer diameter of a cover 60 described later. In addition, the base end (upper end) of the cylindrical portion 20 is fitted and fixed to the tip end (lower end) of the cover 60. In other words, the cylindrical portion 20 rotates integrally with the cover 60 and can be said to be an extension of the cover 60.

<Socket>
The socket 30 is a tubular member made of metal or resin that is fitted onto the rotating shaft 10 and the bolt 2. The base end (upper end) of the socket 30 is the tip end (lower end) of the rotating shaft, and is detachably fitted onto and fixed to a portion exposed from the tubular portion 20. The tip end (lower end) of the socket 30 can be fitted onto the head 2a of the bolt 2.

<Support part>
The support part 40 is a member that supports the ultrasonic sensor 50 on the tip of the rotating shaft 10. The support part 40 is formed of a resilient coil spring or the like. Some of the functional components of the ultrasonic sensor 50 are built into the support part 40. In other words, the support part 40 can be said to be a part of the ultrasonic sensor 50.

<Ultrasonic sensor>
The ultrasonic sensor (ultrasonic probe) 50 is a substantially cylindrical member attached to the tip (lower end) of the tube portion 20 inside the socket 30. The ultrasonic sensor 50 includes a piezoelectric element and the like that oscillates an ultrasonic pulse and receives an echo of the oscillated ultrasonic pulse.

<Cover>
The cover 60 is a cylindrical metal or resin member that is held by the arm portion 7 on the other end side and is fitted on the base end side of the rotating shaft 10. The inner diameter of the cover 60 is larger than the outer diameter of the rotating shaft 10. The cover 60 is attached by bearings B1 and B2 so as to be rotatable relative to the rotating shaft 10. The axis (rotation axis) of the cover 60 is positioned on the same line as the axis (rotation axis) of the rotating shaft 10. The cover 60 is, for example, integrally connected to a cover at the upper end of the nut runner 9 in which the motor M is housed, and may be held by the arm 7 on the other end side via the cover.

<Steering wheel cover>
The handle cover 70 is a cylindrical metal or resin member that is fitted onto the tip end side (tubular portion 20) of the rotating shaft 10. The inner diameter of the handle cover 70 is larger than the outer diameter of the tubular portion 20. The handle cover 70 is attached by bearings B3 and B4 so as to be rotatable relative to the tubular portion 20. The axis (rotation axis) of the handle cover 70 is aligned on the same straight line as the axis (rotation axis) of the rotating shaft 10.
The outside diameter of the handle cover 70 is formed to be approximately the same as the outside diameter of the cover 60. The handle cover 70 is configured so that the position and posture of the nut runner 9 supported by the movable arm (arm portion 7 and joint portion 8) can be changed three-dimensionally by the user. The handle cover 70 includes a cylindrical main body portion 71 and a switch (switch portion) 72 provided in a hole portion 71a formed on the base end side of the main body portion 71. The switch 72 is for operating the drive portion M. The switch 72 includes a main body portion 72a supported swingably on the base end side of the peripheral portion of the hole portion 71a, and a piece portion 72b extending from the tip end portion of the main body portion 73a and accommodated in the main body portion 71 on the tip end side of the peripheral portion of the hole portion 71a. The base end portion (upper end portion) of the main body portion 71 is fitted onto the tip end portion (lower end portion) of the cover 60.

<Switch terminal>
The switch terminal 81 is a cylindrical member fitted onto the cylindrical portion 20. In this embodiment, the switch terminal 81 is attached to the cylindrical portion 20 so as to be rotatable integrally therewith. When the main body 72a of the switch 72 is pressed down by a user, the switch terminal 81 comes into contact with the piece 72b of the switch 72 and generates an electrical signal to the control unit C. Even when the handle cover 70 rotates relative to the rotating shaft 80 and/or the cylindrical portion 20, the piece 72b and the switch terminal 81 slide against each other, so that the switch terminal 81 maintains contact with the piece 72b.

<First terminal>
The first terminal 82 is a tubular member fitted onto the rotating shaft 10 on the base end side relative to the handle cover 70. In this embodiment, the first terminal 82 is attached to the rotating shaft 10 so as to be integrally rotatable with the rotating shaft 10. The first terminal 82 is electrically connected to the ultrasonic sensor 50 by wiring (not shown) that passes through the rotating shaft 10 and a hole formed in the rotating shaft 10.

<Second Terminal>
The second terminal 83 is attached to the inner peripheral surface of the cover 60 and is a member electrically connected to the first terminal 82. Even when the rotating shaft 10 rotates relative to the cover 60, the second terminal 83 maintains an electrical connection with the first terminal 82 as the first terminal 82 and the third terminal 83 slide against each other. The second terminal 83 is electrically (communicatively) connected to the control unit C by a wiring (not shown).

<Connection structure between switch terminal and control unit>
Here, a connection structure between the switch terminal 81 and the control unit C, i.e., a signal transmission structure from the switch terminal 81 to the control unit C, will be described. In this embodiment, the switch terminal 81 is connected to the connector C1 via wiring (not shown) that is arranged through the spaces between the tubular portion 40 and the handle cover 70 and the cover 60, and through a hole formed in the cover 60. The connector C1 is exposed to the outside of the cover 60, and is connected to the control unit C outside the cover 60 via connection terminals and wiring (not shown). The connection with the control unit C using the connector C1 is particularly suitable when the control unit C is provided outside the nut runner 9.

<Connection structure between ultrasonic sensor and control unit>
Next, a connection structure between the ultrasonic sensor 50 and the control unit C, i.e., a transmission structure of the detection result of the ultrasonic sensor 50 from the ultrasonic sensor 50 to the control unit C will be described. In this embodiment, the ultrasonic sensor 50 is connected to the first terminal 81 by a wiring (not shown) arranged inside the support part 40, inside the rotating shaft 10, and through a hole formed in the rotating shaft 10. The second sensor 82 is connected to the connector C2 through a wiring (not shown) arranged in the space between the rotating shaft 10 and the cover 60. The connector C2 is exposed outside the cover 60, and is connected to the control unit C outside the cover 60 through a connection terminal and wiring (not shown). The connection with the control unit C using the connector C2 is particularly suitable when the control unit C is provided outside the nut runner 9.

<Example of operation>
The user places the object to be measured on the base unit 6. Here, the object to be measured is positioned so that the female screw portion formed on the object to be measured has an opening at the top and extends in the vertical direction. In addition, the user sets, as an initial setting, the position of the vertical arm unit 6 on the base unit 3 and/or the vertical position of the first arm unit 7 relative to the vertical arm unit 6 and the orientation around the vertical axis.

Next, with the head 2a of the bolt 2 held by the socket 30 and the ultrasonic sensor 50 in contact with the head 2a of the bolt 2 via an ultrasonic transmission member (elastomer, etc.) not shown, the user grasps and operates the main body 71 of the handle cover 70, and places the shaft 2b of the bolt 2 on the female thread formed in the object to be measured. Here, since the handle cover 70 is rotatable relative to the rotating shaft 10, etc., and also rotatable relative to the cover 60 and the tube portion 20, the user can change the position and attitude of the nut runner 9 in three dimensions while keeping the switch 72 in a position suitable for the user.

Next, the user presses the main body 72a of the switch 72 (see the two-dot chain line in FIG. 2). As a result, the one part 72b of the switch 72 connects to the switch terminal 81, and the switch terminal 81 outputs a signal to the control unit C of the bolt axial force measuring device 1 via the connector C1. Next, when the control unit C receives the signal, it drives the drive unit M (motor, etc.) to rotate the rotating shaft 10, the socket 30, the support unit 40, and the ultrasonic sensor 50 around the axis of the rotating shaft 10. As a result, the shaft portion 2b of the bolt 2 is screwed into the female thread of the measurement object. In addition, the ultrasonic sensor 50 periodically oscillates ultrasonic pulses. The control unit C acquires the reception results (detection results) of the echo from the head 2a of the bolt 2 of the ultrasonic pulse and the echo from the tip of the shaft portion 2b of the bolt 2 via the first terminal 82, the second terminal 83, and the connector C2. The control unit C calculates the bolt axial force based on the reception results of the echo. The control unit C stops the drive unit M when the main body 73a of the switch 73 is released and there is no signal from the switch terminal 81, when the bolt axial force exceeds a predetermined value, etc. In this way, the electrical signal between the control unit C and the ultrasonic sensor 50 is transmitted via the first terminal 82 and the second terminal 83, which remain connected to each other even when the rotating shaft 10 rotates.

A bolt axial force measuring device (nut runner operating device) 1 according to an embodiment of the present invention comprises a nut runner 9 capable of tightening a bolt 2, and a movable arm supporting the base end side of the nut runner 9. The nut runner 9 comprises a drive shaft (rotating shaft 10) rotatable by a drive unit M, an ultrasonic sensor 50 provided at the tip of the drive shaft, and a handle cover 70 which is exteriorly mounted so as to be rotatable relative to the drive shaft. The handle cover 70 is configured so that a user can change the position and attitude of the nut runner 9 supported by the movable arm, and has a switch unit for operating the drive unit M.
Therefore, the bolt axial force measuring device (nut runner operation device) 1 can effectively assist the user in changing the three-dimensional position and posture, and can achieve accurate bolt axial force measurement.

Moreover, in the bolt axial force measuring device (nut runner operating device) 1, the nut runner 9 is fitted onto the drive shaft and includes a cylindrical first terminal 82 connected to the ultrasonic sensor 50, and a second terminal 83 that can slide to maintain a connection to the first terminal 82 that rotates together with the drive shaft and is connected to a control unit C that calculates the bolt axial force based on the detection result of the ultrasonic sensor 50, and the first terminal 82 and the second terminal 83 are provided on the movable arm side relative to the handle cover 70.
Therefore, compared to a case in which the first terminal 82 and the second terminal 83 are provided radially inside the handle cover 70, the bolt axial force measuring device (nut runner operating device) 1 prevents the handle cover 70 from becoming larger in the radial direction, and improves operability (handling) for the user.

When tightening the bolt 2 while controlling the bolt axial force, the bolt axial force increases linearly according to the rotation angle of the bolt 2. Therefore, to realize advanced control such as monitoring and judging the bolt axial force rate, a continuous tightening operation is preferable, rather than an intermittent operation such as an impact tool. In this case, a mechanism for receiving the tightening reaction force is necessary, but setting up such a mechanism every time according to the object to be measured leads to a deterioration in workability.
Furthermore, when measuring the axial force, it is desirable to place the ultrasonic sensor 50 perpendicular to the bolt 2, but this may be difficult to achieve through user operation alone.

In contrast to this, in the bolt axial force measuring device (nut runner operating device) 1, the movable arm constitutes a link mechanism having at least two rotation shafts.
Therefore, the bolt axial force measuring device (nut runner operating device) 1 effectively assists the user in operating the nut runner 9 (changing its position and posture) by means of the movable arm, and can receive the tightening reaction force of the bolt 2 acting on the nut runner 9 by means of the movable arm, thereby improving workability.

The bolt axial force measuring device (nut runner operation device) 1 also includes a handle cover 70 having a switch 72 and capable of rotating relative to the rotating shaft 10. This allows the bolt axial force measuring device (nut runner operation device) 1 to maintain the switch 72 in a position that is easy for the worker to press even if the position or posture of the nut runner 9 changes, eliminating the need for the worker to work in an awkward posture regardless of the tightening position (phase). Furthermore, because the ultrasonic sensor 50 is built into the nut runner 9 of the bolt axial force measuring device (nut runner operation device) 1, the nut runner 9 can be selected and attached to the movable arm according to the required performance, price, etc.

In addition, in the bolt axial force measuring device (nut runner operating device) 1, the movable arm has a parallel crank mechanism.
Therefore, the bolt axial force measuring device (nut runner operation device) 1 can change the position of the nut runner 9 while maintaining the attitude of the nut runner 9 by the parallel crank mechanism, and can always orient the nut runner 9 in the vertical direction, for example. In other words, the bolt axial force measuring device (nut runner operation device) 1 can assist in bringing the ultrasonic sensor 50 provided at the tip of the nut runner 9 into perpendicular contact with the bolt 2 that is screwed into the female thread of the object to be measured.
Furthermore, the bolt axial force measuring device (nut runner operation device) 1 is provided with a handle cover 70 having a switch 72 and rotatable relative to the rotating shaft 10. As a result, the bolt axial force measuring device (nut runner operation device) 1 maintains the switch 72 in a position that is easy for an operator to press even if the position or posture of the nut runner 9 changes, and can eliminate the need for the operator to work in an awkward posture regardless of the tightening position (phase). Furthermore, since the bolt axial force measuring device (nut runner operation device) 1 has the ultrasonic sensor 50 built into the nut runner 9, it is possible to select a nut runner 9 according to the required performance, price, etc., and attach it to the movable arm.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and can be modified as appropriate within the scope of the present invention. For example, the ultrasonic sensor 50 may be configured to oscillate an ultrasonic pulse under the control of the control unit C. In this case, when the control unit C acquires a signal output from the switch terminal 81 when the one part 72b of the switch 72 is connected to the switch terminal 81, the control unit C can transmit a signal to the ultrasonic pulse via the connector C2, the second terminal 83, and the first terminal 82, thereby causing the ultrasonic sensor 50 to oscillate an ultrasonic pulse. In other words, the switch 72 is for activating the ultrasonic sensor 50 in addition to the drive unit M.

1. Bolt axial force measuring device (nut runner operating device)
2 Bolt 3 Base portion 6 Vertical arm portion 7 Arm portion (movable arm)
7A, 7B, 7C Parallel crank mechanism 8 Joint (movable arm)
9 Nut runner 10 Rotating shaft (drive shaft)
20: Cylinder portion 30: Socket 40: Support portion (ultrasonic sensor)
50 Ultrasonic sensor 60 Cover 70 Handle cover 71 Main body 71a Hole 72 Switch (switch portion)
81 Switch terminal 82 First terminal 83 Second terminal B1, B2, B3, B4, B5 Bearings C Control unit M Drive unit

Claims (3)

A nut runner capable of tightening a bolt;
A movable arm that supports a base end side of the nut runner;
Equipped with
The nut runner comprises:
A drive shaft rotatable by a drive unit;
an ultrasonic sensor provided at a tip of the drive shaft;
a handle cover that is rotatably mounted on the drive shaft;
Equipped with
The handle cover is
The position of the nut runner supported by the movable arm can be changed by a user,
A switch unit for operating the drive unit is provided,
The nut runner comprises:
a cylindrical first terminal that is fitted onto the drive shaft and is connected to the ultrasonic sensor;
A second terminal that can maintain a sliding connection with the first terminal that rotates together with the drive shaft and is connected to a control unit that calculates the bolt axial force based on the detection result of the ultrasonic sensor;
Equipped with
the first terminal and the second terminal are provided closer to the movable arm than the handle cover,
The nut runner operating device, wherein the handle cover and the second terminal are each independently rotatable relative to the drive shaft. The nut runner operating device according to claim 1 , wherein the movable arm constitutes a link mechanism having at least two rotation shafts. The nut runner operating device according to claim 1 , wherein the movable arm has a parallel crank mechanism.

Images