JPH04256529A - Bolt and nut tightening device - Google Patents

Abstract

PURPOSE:To engage and tighten a socket with a bolt securely by increasing the aligning property of the socket, even if the axis of the socket of a bolt and nut tightening device is deviated largely from that of the bolt. CONSTITUTION:A step 8c is provided at the top end 8b of a nearly cylindrical socket 8 supported so that it may be displaced in perpendicular direction relative to the center axis of the socket 8. Also inclination is provided at the top end 8b in the direction reverse to the rotation of the socket 8 toward the bottom 8h of the step 8c. With this, even if the maximum height position 8f of the step 8c of the socket 8 is brought into contact with the top surface of the head of a bolt 4, the lower surface at the top end 8b of the socket 8 is brought to contact with the top surface of the head of the bolt 4 as the socket 8 is rotated. In addition, the step 8c of the socket 8 is rotated fully one time and is brought into contact with the side surface of the head of the bolt 4. By the reaction force due to this contact, the socket 8 receives force in the direction that its axis coincides with that of the bolt 4.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bolt/nut tightening device for tightening, for example, a bolt or nut temporarily tightened at a predetermined position on a workpiece.

0002

2. Description of the Related Art A socket in a conventional bolt/nut tightening device generally has a chamfered edge on the inner peripheral side of its tip. As a result, even if the axial center of the bolt deviates from the axial center of the socket, engagement between the two is possible as long as the deviation is small. That is, the socket has an alignment property that aligns its axis with the axis of a bolt or the like.

0003

However, as shown in FIG. 5, the axial center of the bolt 40 and the axial center of the socket 80 are largely misaligned, and a part of the head of the bolt 40 is dislocated from the socket 80.
If the socket 80 is located outside the outer periphery of the socket 80, the socket 80 will no longer be able to engage with the socket 80, and the socket 80 will simply idle in vain. Therefore, in order to reliably tighten the bolt 40, it is necessary to correctly arrange the workpiece so that the axis of the bolt 40 and the axis of the socket 80 do not deviate, but the workpieces flow continuously during assembly work. It is difficult to place the workpiece in an accurate position. The technical problem of the present invention is to improve the alignment of the socket so that bolts and nuts can be reliably tightened even if the axis of the bolt, etc. screwed onto the workpiece and the axis of the socket are significantly misaligned. The object of the present invention is to provide a tightening device.

0004

[Means for Solving the Problems] A bolt/nut tightening device according to the present invention has the following structure. In other words, a socket supported so as to be displaceable in a direction perpendicular to the axis,
In a bolt/nut tightening device that engages and tightens the head of a bolt or a nut by rotating the socket around its axis and moving it in the axial direction, the socket has a stepped portion on its distal end surface. At the same time, this tip surface is inclined toward the bottom of this stepped portion from a direction opposite to the rotation of the socket.

[0005]

[Operation] According to the present invention, even if the highest point of the step on the tip of the socket comes into contact with the top surface of the head of the bolt when the axis of the bolt and the axis of the socket are largely misaligned, the socket As the socket rotates, the lower end of the socket comes into contact with the top of the bolt head. Furthermore, the stepped portion of the socket rotates once and comes into contact with the side surface of the head of the bolt. Due to the reaction force caused by this contact, the socket receives a force in a direction in which its axial center coincides with the axial center of the bolt. Furthermore, as the socket continues to rotate, the stepped portion moves along the circumference of the bolt head while remaining in contact with the side surface of the bolt head, and the socket engages with the bolt head. be done. Therefore, even if the axial center of the bolt and the axial center of the socket are largely misaligned, the bolt can be reliably tightened.

[0006]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 4 shows a bolt/nut tightening device 1 according to this embodiment.
This is an overall diagram. The bolt/nut tightening device 1 is a device for automatically tightening a plurality of bolts 4 that are temporarily tightened in order to fix the differential 2 in a predetermined position of the support member 3, and corresponds to the number of bolts 4 to be tightened. The nut runner 6 has a number of nut runners 6 and a socket 8 rotated by the nut runner 6. The nut runner 6 is attached to a frame 7 such that the axis of each socket coincides with the axis of each bolt 4, and when tightening the bolts 4, the frame 7 is lowered by a predetermined distance by a lifting device (not shown). Ru.

FIG. 2 shows a connection structure between the nut runner 6 and the socket 8. The nut runner 6 uses gears to reduce the rotation of an air motor (not shown) and rotates the main shaft 6a. A coil spring 12 is connected to the main shaft 6a via a connecting member 10 so that its axes coincide with each other, and a socket 8 is also connected to the other end of the coil spring 12 coaxially with the main shaft 6a. With this structure, when the main shaft is rotated, the socket 8 is rotated around the axis. Furthermore, the main shaft 6a of the nut runner 6 and the socket 8
Since a coil spring 12 is interposed between the socket 8 and the socket 8, the socket 8 can be slightly displaced in the direction perpendicular to the axis.

FIG. 1 is a detailed view of the socket 8, and FIG.
A) is a front view, FIG. 1(B) is a view along the line BB in FIG. 1(A), and FIG. 1(C) is a partially cutaway sectional view of FIG. 1(A). The socket 8 has a substantially cylindrical shape, and its inner wall surface is provided with six protrusions 8a that protrude in the radial direction, as shown in FIG. 1(B). When the socket 8 is placed coaxially over the head of the bolt 4 or a nut (not shown), the convex portion 8a abuts against the side surface of the head of the bolt 4 or the side surface of the nut. As a result, the socket 8 and the bolt 4 or nut are engaged with each other so as to be immovable relative to rotation in the axial direction.

The distal end surface 8b of the socket 8 has a ring-shaped planar shape as shown in FIG. 1(B), and one part of the ring is a stepped portion 8c. This stepped portion 8c is provided with a predetermined inclination in the radial direction so that when the socket 8 rotates, the outer peripheral end 8d precedes the inner peripheral end 8e. Moreover, this tip surface 8b is
As shown in FIG. 1(A), the socket 8 gradually becomes lower from the highest point 8f of the stepped portion 8c in the direction opposite to the rotation of the socket 8 until reaching the bottom 8h of the stepped portion 8c. That is, the distal end surface 8b is inserted into the stepped portion 8c from the direction opposite to the rotation of the socket 8.
is inclined toward the bottom 8h. Furthermore, the tip surface 8b is sloped so that the cross-hatched portion in FIG. 1(B) becomes lower toward the center of the socket 8.

Next, the operation of the bolt/nut tightening device 1 according to this embodiment will be explained. Bolt nut tightening device 1
When the differential 2 and the like are set at a predetermined position, the bolt/nut tightening device 1 is driven and the pedestal 7 supporting the nut runner 6 is lowered by the lifting device. Furthermore, at approximately the same time, the socket 8 is rotated by the nut runner 6. If the axial center of the socket 8 and the axial center of the bolt 4 temporarily tightened to the differential 2 etc. are approximately aligned, the socket 8 rotating around the axial center will come into contact with the head of the bolt 4. It quickly engages and tightens.

Furthermore, as shown in FIG. 3, when the axis of the bolt 4 and the axis of the socket 8 are largely misaligned, it is assumed that the highest point 8f of the stepped portion 8c of the socket end face 8b is located at the bolt 4.
Even if the socket 8 contacts the top surface 4a of the head of the bolt 4, as the socket 8 rotates, the lower end surface 8b of the socket 8 comes to contact the top surface 4a of the head of the bolt 4. Then, the stepped portion 8c of the socket 8 rotates once,
This abuts against the side surface 4b of the head of the bolt 4. Due to the reaction force caused by this contact, the socket 8 receives a force in a direction in which its axial center coincides with the axial center of the bolt 4. Furthermore, by continuing to rotate the socket, the stepped portion 8c
moves along the circumference of the head of the bolt 4 while being in contact with the side surface 4b of the head of the bolt 4, and the socket 8 moves around the head of the bolt 4.
is engaged with the head of the

As described above, in the bolt/nut tightening device 1 according to the present embodiment, even if the axial center of the socket 8 and the axial center of the bolt 4 temporarily tightened to the differential 2 etc. are misaligned, the socket 8 and the head of the bolt 4 can be engaged with each other.

[0013]

[Effects of the Invention] The socket according to the present invention can engage the head of a bolt, etc., even if its axial center is largely misaligned with the axial center of the bolt, etc., and the socket can be used to engage the head of a bolt, etc. Even if the arrangement deviates from the normal arrangement, bolts, etc. temporarily fastened to the workpiece are reliably tightened, and the number of defective tightenings is reduced.

[Brief explanation of the drawing]

FIG. 1 is a detailed view of a socket.

FIG. 2 is a diagram of a connection structure between a nut runner and a socket.

FIG. 3 is a diagram showing a tightening state in a state where the axial center of the bolt and the axial center of the socket are largely misaligned.

FIG. 4 is an overall view of the bolt/nut tightening device according to the present embodiment.

FIG. 5 is a diagram showing a state in which the axial center of the bolt and the axial center of the socket are largely misaligned in a conventional bolt/nut tightening device.

[Explanation of symbols]

4 bolt 6 Nut runner 8 Socket 8b Socket tip surface 8c Step part 8f Highest point of step part 8h Bottom of step part

Claims (1)

[Claims] [Claim 1] A socket that is supported so as to be displaceable in a direction perpendicular to the axis is engaged with the head of a bolt or a nut by moving the socket in the axial direction while rotating the socket about the axis. In the bolt/nut tightening device that performs the tightening, a step is provided on the tip surface of the socket, and the tip surface is inclined toward the bottom of the step from the direction opposite to the rotation of the socket. A bolt and nut tightening device characterized by: