JPH0422928Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a socket used for tightening bolts, and in particular, to an ultrasonic socket that is equipped with an ultrasonic sensor in the socket that detects the axial force of the bolt using ultrasonic waves. This relates to a socket with a built-in sensor.

Background of the invention The applicant previously developed a bolt tightening device equipped with a socket with a built-in ultrasonic sensor as described above, and filed an application for registration of a utility model. This is the case currently being filed as Utility Model Application No. 130506/1983.

In this method, an ultrasonic sensor is installed in a fitting hole that is non-rotatably fitted to the bolt head of the socket body, and when the socket is fitted to the bolt head, the ultrasonic sensor is inserted into the bolt head. in contact with the top surface,
The bolt is tightened while measuring the axial force of the bolt by emitting ultrasonic waves based on an electrical signal supplied from the outside. In order to measure the axial force of a bolt, an ultrasonic sensor emits an echo of the ultrasonic wave from the bolt shaft end face, converts it into an electrical signal, and measures the time from when the ultrasonic wave is transmitted to when the echo is received. There are methods that utilize the fact that time or the time interval from receiving the primary echo to receiving the secondary echo changes in response to the amount of bolt extension, and the natural frequency of the bolt in its natural state and the natural frequency after tightening. Methods such as determining the axial force based on the difference between the vibration frequency and other methods are used, but in any case, using this device, the bolt can be tightened while actually measuring the axial force of the bolt. Work can be managed with high precision.

However, subsequent research revealed that there was still room for improvement in this device. In other words, in order to improve the accuracy of bolt axial force measurement, it is desirable to place the ultrasonic sensor in close contact with the top surface of the bolt head as accurately as possible, but in the socket of the bolt tightening device developed earlier, Since the ultrasonic sensor was fixedly installed at the bottom of the fitting hole of the socket, in order to accurately attach the ultrasonic sensor to the top of the bolt, the socket itself had to be positioned accurately relative to the bolt head. It was necessary to rotate the bolt, which required high precision for the bolt and its tightening device as a whole, and the tightening work required great care.

Purpose of the invention With the above-mentioned circumstances as a background, the present invention has been developed to develop an ultrasonic sensor that allows the ultrasonic sensor to remain in close contact with the top surface of the bolt head with high accuracy even if the relative position of the socket to the bolt head changes slightly. This was developed for the purpose of providing a socket with a built-in sonic sensor.

Structure of the invention In order to achieve the above object, the socket with a built-in ultrasonic sensor according to the invention is provided with a fitting hole that is fitted with the head of the a-bolt in a relatively non-rotatable manner. A socket body that is rotated around a line, and a hollow part formed in the socket body concentrically with the fitting hole and continuous with the fitting hole on the opposite side from the opening side of the socket body. a first holding member disposed with a gap between the first holding member and the inner circumferential surface; a first elastic member that is held approximately on the centerline of the fitting hole and allows movement in a direction perpendicular to the centerline by elastic deformation, but does not allow substantial movement in a direction parallel to the centerline; , d, the first holding member is not relatively movable in the direction from the back side of the fitting hole toward the opening side, but is relatively movable in the direction from the opening side to the back side, and has a relative inclination. The second holding member is engaged in a state in which relative movement in the direction perpendicular to the center line of the fitting hole is possible but virtually impossible, and a second elastic member which is biased in the direction toward the opening side; and an ultrasonic sensor that converts this into an electrical signal.

Effects of the invention When the socket with a built-in ultrasonic sensor configured as described above is used by attaching it to a rotary drive device, even if the socket body moves somewhat relative to the bolt head, the relative movement will be the first. This is absorbed by the elastic deformation of the first elastic member and the second elastic member, and the ultrasonic sensor can maintain a state in close contact with the top surface of the bolt head with high accuracy, and can move relative to the top surface in a direction parallel to the top surface. Nor.

Therefore, ultrasonic waves can be reliably transmitted from the ultrasonic sensor to the bolt and vice versa without positioning the socket with respect to the bolt head with such high precision, and the ultrasonic sensor and the bolt can be easily transmitted. There is no longer an error in measuring the axial force due to fluctuations in the gap between the two. As a result, the manufacturing cost of the bolt tightening device is reduced, and the tightening work does not require as much care, making it easier to apply the method of tightening bolts while measuring axial force to actual production lines. This results in an effect that makes it easier.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

FIG. 1 is a diagram showing a state in which an ultrasonic sensor built-in socket 8, which is an embodiment of the present invention, is attached to a rotating shaft 12 of a rotary drive device 10 by a coupling pin 13. The main body of the socket 8 is divided into a first member 14 and a second member 16.
The protrusion is fitted into the fitting hole of the second member 16, and
They are connected by a set screw 18.

The second member 16 is a substantially cylindrical member, and includes a hollow portion 20 and a fitting hole 22 that are formed concentrically with each other. The fitting hole 22 is formed with a hexagonal cross-sectional shape at the end opposite to the side joined to the first member 14, and opens at the distal end surface of the second member 16. It is connected to the hollow portion 20 on the opposite side. Although the hollow portion 20 has a circular cross-sectional shape, the hollow portion 20 of the fitting hole 22
A counterbore hole 24 having a circular cross section is also formed in a portion adjacent to the counterbore hole 24.
An ultrasonic sensor 26 (hereinafter simply referred to as a sensor) is disposed inside. This sensor 26 is held by elastic holding means 30 attached to the first member 14 via an extension member 28 .

The elastic holding means 30 includes a first holding member 32 and a second holding member 34. As is clear from FIG. 2, the first holding member 32 is a cylindrical case 3 with a bottom.
A cap 38 is fixed to the opening of the case 3 by caulking or other appropriate means.
The shaft portion 40 of the second holding member 34 is fitted into a circular hole formed in the center of the bottom wall of the second holding member 6 so as to be slidable in the axial direction. Since the gap between this circular hole and the shaft portion 40 is made relatively small, the shaft portion 40 is almost immovable in the radial direction, but since the bottom wall of the case 36 is thin, the first holding member A small angle can be tilted relative to 32. A spring bearing 42 is fixed to one end of this shaft portion 40 by screwing, and when this spring bearing 42 engages with the bottom wall of the case 36, the shaft portion 42
0 is prevented from slipping out of the case 36 beyond a certain limit. Further, the sensor 26 is fixed to the other end of the shaft portion 40 by suitable means such as adhesive, and its working surface 44 faces toward the opening side of the fitting hole 22. Spring receiver 4 of the second holding member 34
2 and the cap 38 of the first holding member 32, a tapered coil spring 46 is disposed.
The second holding member 34 and the sensor 26 fixed to the tip thereof are urged in a direction from the back side of the fitting hole 22 toward the opening side. On the other hand, the first holding member 32 is
It is connected to the free end of the extension member 28 by a tightly wound coil spring 48. Both ends of the tightly wound coil spring 48 are connected to cutting surfaces 50 and 52 formed on the cap 38 and the extension member 28, respectively.
The circular protrusions 54, 5
6, and is engaged with an annular groove formed in a portion adjacent to the cutting surfaces 50 and 52 of 6, so that it does not easily separate from the cap 38 and the extension member 28 even if a tensile force is applied. There is. Although the tightly wound coil spring 48 cannot be compressed, it can be easily bent or sheared in a direction perpendicular to the centerline. Since a radial gap is provided between the outer circumferential surface of the first holding member 32 and the inner circumferential surface of the hollow portion 20, the first holding member 32 is aligned with the center line of the fitting hole 22. It can be easily moved in the right angle direction.

A certain gap exists between the outer peripheral surface of the sensor 26 and the inner peripheral surface of the counterbore hole 24, and the sensor 26 is located at the center line of the counterbore hole 24, that is, the fitting hole 2.
Although it is movable in the direction perpendicular to the center line of the fitting hole 2, when no force is applied, it is almost the same as the fitting hole 2.
It is held on the center line of 2. First holding member 3
2 is connected to the hollow part 2 by a tightly wound coil spring 48.
0, and the second holding member 3
4 is substantially immovable in the radial direction with respect to the first holding member 32 as described above, and the spring receiver 42 is prevented from tilting by being seated on the bottom wall of the case 36. As expected, the hollow part 20
Therefore, the sensor 26 fixed to the tip thereof is also located approximately on the center line of the fitting hole 22.

The sensor 26 emits ultrasonic waves from the working surface 44 based on pulsed electric signals supplied from the outside, and converts the ultrasonic waves into electric signals when the working surface 44 receives the ultrasonic waves. It is connected to an external control device by a signal line 60 for transmitting signals. This signal line 60 is
The second holding member 34, the first holding member 32, the extension member 28, and a through hole formed on the center line of the first member 14 lead to a slightly wider space 62 in the first member 14, where It is connected to another signal line 66 by a connector 64. This signal line 66
is drawn out from the transformer 68, and the transformer 68 includes a rotating coil 70 that is fixed to the outer peripheral surface of the first member 14 and rotates therewith, and a fixed coil 72 that is non-rotatably provided outside of the rotating coil 70.
Even while the first member 14 is rotating, electrical signals can be transmitted between the signal line 66 and the signal cable 74. The fixed coil 72 is fixed to the inner circumferential side of a cylindrical transformer receiver 76, and the transformer receiver 76 is relatively rotatably attached to the first member 14 by a pair of bearings 78, and the fixed plate 80
is fixed to the housing of the rotary drive device 10 by. A control device is connected to an end (not shown) of the signal cable 74, which supplies an electrical signal to the sensor 26, receives the electrical signal from the sensor 26, and calculates the axial force of the bolt based on this. However, this control device is described in detail in the specification of the above-mentioned Utility Application No. 130506/1982, and since it is not essential for understanding the invention of the present application, a detailed explanation will be omitted. is omitted.

Next, the operation will be explained.

When the head of the bolt is inserted into the fitting hole 22 of the socket 8 in order to tighten the bolt, the top surface of the head abuts the working surface 44 of the sensor 26.
As a result, the sensor 26 and the second holding member 34 are moved a short distance from the opening side of the fitting hole 22 toward the back side against the elastic force of the tapered coil spring 46, and the spring of the second holding member 34 is moved. The receiver 42 is raised from the bottom wall of the case 36 of the first holding member 32, and the second holding member 34 is in a state where it can be easily tilted with respect to the first holding member 32. 46
Due to the elastic force of the bolt, it is completely brought into close contact with the top surface of the bolt head.

When the rotating shaft 12 is rotated in this state, the socket 8 also rotates and the bolt is tightened. At this time, if the center lines of the bolt and the socket 8 are slightly misaligned, the bolt will tighten as the socket 8 rotates. Therefore, relative movement occurs between the two in a direction perpendicular to the center line of the fitting hole 22. However, the first holding member 32 holding the sensor 26 is not connected to the fitting hole 2 as described above.
Since the sensor 26 is movable in the direction perpendicular to the center line of the bolt 2, the sensor 26 is also movable, and even if the socket 8 moves relative to the bolt head, the sensor 26 will not move relative to the bolt head. It does not move relative to each other and can remain in the position where it first came into close contact.

Further, if the center line between the bolt head and the socket 8 is inclined, the direction of inclination of the top surface of the bolt with respect to the center line of the fitting hole 22 changes every moment as the socket 8 rotates. However, sensor 2
As described above, the second holding member 34 holding the sensor 26 can be tilted freely with respect to the first holding member 32, so the sensor 26 can also be tilted in the same way, and the bolt head and socket can be tilted freely. It is possible to maintain close contact with the top surface of the bolt head regardless of changes in the relative inclination with respect to 8.

Therefore, the ultrasonic waves emitted from the action surface 44 are reliably transmitted to the bolt, and the echoes reflected from the end face of the bolt shaft are also reliably transmitted to the sensor 26. Note that even if there is a minute gap between the working surface 44 of the sensor 26 and the top surface of the bolt head, ultrasonic waves will be transmitted if there is oil or the like in this gap. In this case, if the gap fluctuates, this will directly result in an error in measuring the amount of bolt extension (that is, the axial force of the bolt). However, in this embodiment, since the sensor 26 is kept accurately in close contact with the top surface of the bolt as described above, such errors hardly occur. Therefore, socket 8
It is possible to perform tightening work while accurately measuring the axial force of the bolt without having to control the relative position of the bolt and the bolt with high precision.

Furthermore, in this embodiment, the movement of the sensor 26 in the direction perpendicular to the center line of the fitting hole 22 is allowed by the elastic deformation of the tightly wound coil spring 48, which is the first elastic member. The movement along the center line from the opening side to the back side and the inclination are allowed by the elastic deformation of the tapered coil spring 46, which is the second elastic member. Therefore, compared to the case where the sensor 26 is attached to the socket body in a floating state using an elastic member such as a single coil spring or a rubber member, the sensor 26 can be pressed almost completely against the top surface of the bolt with an optimal force. It is easy to maintain the sensor 26 in a floating state, that is, to be able to move in any direction with extremely small force, and to maintain the sensor 26 precisely on the center line of the fitting hole 22 when no force is applied. It has certain advantages.

In the above embodiment, the socket body was composed of the first member 14 and the second member 16, but this is not necessarily essential, and it is also possible to construct them integrally. The cross-sectional shape of the fitting hole 22 that is to be fitted with the head is not limited to a hexagonal shape, but it is also possible to have hexagonal shapes overlapped with a phase difference of 30 degrees as in the case of a normal socket. In short, the cross-sectional shape may be such that it can be fitted with the head of the target bolt in a relatively non-rotatable manner.

Although not illustrated in detail, the present invention can of course be implemented with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a front cross-sectional view showing a state in which a sensor built-in socket, which is an embodiment of the present invention, is attached to a rotary drive device, and FIG. 2 is an enlarged view of a part of FIG. 1. be. 14...First member, 16...Second member} Socket body, 20...Hollow part, 22...Fitting hole, 24
...Counterbore, 26...Ultrasonic sensor (sensor),
30... Elastic holding means, 32... First holding member,
34... second holding member, 36... case, 38...
... Cap, 40 ... Shaft, 42 ... Spring bearing, 4
4... Working surface, 46... Tapered coil spring, 48... Closely wound coil spring, 60... Signal line.

Claims (1)

[Scope of Claim for Utility Model Registration] A socket body that is provided with a fitting hole that is non-rotatably fitted with a bolt head and that is rotated around the center line of the fitting hole by a rotational drive device; Arranged in a hollow part formed concentrically with the fitting hole and continuous with the fitting hole on the opposite side to the opening side thereof, with a gap existing between the hollow part and the inner circumferential surface of the hollow part. a first holding member fixed to the socket main body at one end and fixed to the first holding member at the other end to normally hold the first holding member approximately on the center line of the fitting hole; a first elastic member that, upon deformation, allows movement in a direction perpendicular to its centerline but does not allow substantial movement in a direction parallel to its centerline; It is not possible to move relatively in the direction from the back side to the opening side, but it is relatively movable in the direction from the opening side to the back side, and although relative tilting is possible, the center of the fitting hole is a second holding member engaged in a state in which relative movement in a direction perpendicular to the line is substantially impossible; and urging the second holding member in a direction from the back side of the fitting hole toward the opening side. a second elastic member, and an ultrasonic member fixed to the second holding member in the fitting hole, which emits ultrasonic waves from its working surface based on electrical signals, receives ultrasonic waves on its working surface, and converts the ultrasound into electrical signals. A socket with a built-in ultrasonic sensor, including a sonic sensor.