JP3060895B2 - Socket structure of automatic nut tightening device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a socket structure for use in an automatic nut tightening device, and more particularly to a socket structure for an automatic nut tightening device capable of coping with a deviation in the axis between a bolt and a nut.

[0002]

2. Description of the Related Art In an automatic nut tightening device, an automatic nut tightening socket is mounted at the tip of a nut runner. As shown in FIG. 33, a concave portion 51 into which the nut 31 is fitted is provided at a tip portion (a malleable portion in the figure) of the socket 51.
A is provided. A magnet (not shown) is provided around the concave portion, and the nut 31 is held in the concave portion 51A, and the bolt is tightened in this state. By the way, in order to reliably insert the nut 31 into the recess 51A of the socket 51, for example, as shown in FIG. 34, a gap t is secured between the inner surface of the recess 51A and the outer surface of the nut 31. Is set.

However, because of this gap t,
Even if the nut 31 can be reliably positioned on the bolt 3, for example, as shown in FIG.
1 is tilted in the socket 51, so that an angle α is generated between the axes. On the other hand, the bolt 32 to which the nut 31 is to be tightened also has an angle β with respect to the regular mounting angle (the angle along the axis of the socket) depending on the mounting accuracy. As a result, the relative angle θ between the nut 31 and the bolt 32
May reach α + β, for example, as shown in FIG. Thus, the nut 31 and the bolt 32
When the relative angle θ with respect to the above becomes large, the bolt 32 cannot enter the nut 31, and as shown in FIG.

In order to avoid such an inferior fastening, instead of the standard bolt 33 as shown in FIG. 36A, for example, a pointed bolt 34 with a nut guide as shown in FIG. Even when the relative angle θ between the nut 31 and the bolt 32 is large, it is sharp. There is a means for allowing the bolt 32 to enter the nut 31 through the guide. There is also a means using a special nut with a guide or the like instead of the standard nut. Further, a means for providing a sensor or the like for detecting the relative angle between the nut and the bolt and correcting the relative angle between the nut and the bolt based on the detection result to avoid the fastening failure may be considered.

For example, as a means for correcting the relative angle, there is an automatic nut tightening device disclosed in Japanese Patent Application Laid-Open No. 63-200930. In this device, a socket for holding the nut and a support member for the socket are provided. In between, a cam structure for correcting the vertical displacement of the socket with respect to the bolt 32 and an elastic body for correcting the relative angle of the socket with respect to the bolt 3 are provided.

[0006]

However, among the conventional means for avoiding the above-mentioned fastening failure, those using a special structure for the bolt or nut have a problem that the component cost increases. In the case of performing angle correction using a sensor or the like, there is a problem that a large increase in cost is generally caused.

Further, in the apparatus disclosed in Japanese Patent Application Laid-Open No. 63-200930, for example, if the nut is not completely fastened to the bolt and is engaged, the vertical displacement cannot be corrected, and each mechanism and the like cannot be corrected. There is also a risk of causing damage to the mechanical parts. In addition, although the change of the angle of the socket is allowed for the correction of the relative angle through the elastic body, the elastic force of the elastic body does not increase the moment until the nut is positively aligned with the bolt axis. It is difficult to give it, and there is a possibility that fastening failure cannot be avoided reliably. Furthermore, since the movement of the nut in the socket is not restricted, there is a problem that the gap moves between the socket and the nut, causing the nut to move irregularly, making it difficult to obtain stable fastening.

An object of the present invention is to provide a socket structure of an automatic nut tightening device which can reliably avoid a defective connection between a nut and a bolt without using a standard bolt or a standard nut without increasing costs. It is in.

[0009]

To achieve the above object, according to the first aspect of the present invention, a socket of an automatic nut tightening device for tightening a nut to a bolt by rotating the nut while holding the nut. In the structure, a socket body having a nut holding space at a distal end portion, a centering device for supporting the socket body movably in a horizontal direction orthogonal to an axis of the socket body, and a nut supported by the socket body via a bracket. A conical concave guide surface centered on the holding space is formed, and when the concave guide surface abuts on the bolt, relative displacement between the nut hole in the nut holding space and the bolt is eliminated. A guide member for generating a position correcting force in a direction in which the nut and the bolt are supported by the bracket and the nut and the bolt are engaged. The guide position, and the guide member switching means to be switched moved to the retracted position when retrofitting the clamping engagement of the nut and bolt, the hole of the inner side of the nut holding space
Attached so that it can be arranged and slide in the axial direction
A slider, and a swingably mounted at the tip of the slider.
To hold the nut with its axis aligned.
Directly or indirectly against the bolt holding surface and the tip of the bolt.
Nut direction to align the axis of the nut and the bolt
A nut regulating jig having an adjustment surface and the slider
First urging for urging the nut regulating jig toward the bolt side
Means and the nut set on the nut regulating jig.
A second urging means for urging the bolt side .

[0010]

According to a second aspect of the present invention, in the socket structure of the automatic nut tightening device according to the first aspect, the guide member is formed as a pair of bolt guides provided so as to sandwich the socket body. In the guide position, the pair of bolt guides form the concave guide surface, and the guide member switching means is interlocked with the sliding of the slider against the first biasing means, and the pair of bolt guides is located at the guide position. The concave guide surface of the bolt guide is divided into two and switched to a retreat position where they are separated from each other.

According to a third aspect of the present invention, in the socket structure of the automatic nut tightening device according to the first aspect, the guide member is pivotally supported by the bracket and has a guide shaft formed with a claw portion at one end. A curved guide surface which is continuous with the claw-shaped portion toward the center of the nut holding space at the guide position, and wherein the guide member switching means is configured to be opposed to the first urging means. The guide shaft is rotated in conjunction with the sliding of the slider, and the claw portion at the guide position is switched to the retreat position and moved.

[0013]

According to the first aspect of the invention, when the socket body is driven to rotate while holding the nut in the nut holding space at the tip of the socket body, the centering device moves the socket body in a horizontal direction orthogonal to the axis of the socket body. Then, when tightening the nut to the bolt, the guide member supported via the bracket to the socket body is rotationally driven, and the concave guide surface comes into contact with the bolt, so that the nut holding space can be adjusted. A position correcting force is generated in a direction to eliminate the relative displacement between the nut hole and the bolt in the inside. In particular, the slider arranged in the hole on the back side of the nut holding space is mounted so as to be slidable in the axial direction, is mounted swingably at the tip of the slider, and the nut is aligned with its axis. A nut restricting jig having a nut holding surface for holding, and a nut direction adjusting surface for directly or indirectly abutting on the tip of the bolt to align the axis of the nut and the bolt; The nut regulating jig is urged toward the bolt through the slider, and the nut set on the nut regulating jig is urged toward the bolt by the second urging means. Further, the guide member is switched by the guide member switching means supported by the bracket to the guide position when the nut and the bolt are engaged with each other, and to the retreat position when the nut and the bolt are fastened after the engagement.

[0014]

[0015] Therefore, the centering device is a socket
Rotate the body easily while correcting the relative position with the bolt,
At this time, the nut holding surface of the nut regulating jig holds the nut
The nut adjusting jig is aligned with the axis of the nut , and the nut direction adjusting surface of the nut regulating jig directly or indirectly abuts on the tip of the bolt to align the nut and the axis of the bolt. Since the restricting jig is urged toward the bolt and the second urging means urges the nut toward the bolt, the inclination of both axes of the nut and the bolt is eliminated, and the engagement is reliably achieved. In addition, since the guide member moves to the retreat position at the time of tightening after the engagement of the nut and the bolt is established, the nut and the bolt are securely tightened without interference with the guide member.

According to a second aspect of the present invention, in the socket structure of the automatic nut tightening device according to the first aspect, in particular, the guide member is formed as a pair of bolt guides provided so as to sandwich the socket body, and At the guide position, the pair of bolt guides are formed with a conical concave guide surface centered on the nut holding space, and the guide member switching means is interlocked with sliding of the slider against the first biasing means, The pair of bolt guides at the guide position are switched to a retreat position where the concave guide surface is divided into two and separated from each other. In this case, a divided structure with a pair of bolt guides
When the conical concave guide surfaces of the pair of bolt guides rotate together with the socket body, a position correcting force is generated, and the socket body and the pair of bolt guides are displaced.
The holes in the nut and the bolts are aligned with each other so that they are properly engaged.

According to the third aspect of the present invention, in the socket structure of the automatic nut tightening device according to the first aspect, in particular, the guide member includes a guide shaft pivotally supported by the bracket and having a claw-like portion formed at one end. A curved guide surface is formed on the claw-shaped portion and continues toward the center of the nut holding space at the guide position, and the guide member switching means is configured to prevent the slider from sliding against the first biasing means. The guide shaft is rotated in conjunction therewith, and the pawl at the guide position is switched to the retreat position and moved. In this case, when the curved guide surface of the claw portion rotates together with the socket body, a position correcting force is generated, the claw portion on the socket body and the guide shaft is displaced, and both the axis of the nut hole and the bolt are aligned. Align and engage properly.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an embodiment of an automatic nut tightening device according to the present invention; FIG. 2 is a vertical partial sectional view showing an attached state. FIGS. 3 to 21 are a detailed view and a functional explanatory view of each component of the socket structure of the automatic nut tightening device shown in FIG. First, the entire configuration of the tool having the socket structure of the present automatic nut tightening device will be described. As shown in FIG. 1, the socket 1 of the automatic nut tightening device is mounted on the tip of a nut runner 11. Centering device 1
6. The position is regulated by the adapter 41 and the socket guide 17, and the spindle 12 mounted at the center of the tip of the nut runner 11 receives rotational driving force via the universal joint 43 and the socket joint 44.

The nut runner 11 is attached to a robot 13 for driving the nut runner 11 to a desired position by a bolt or the like (not shown) via a nut runner adapter 14 and an adapter plate 15. Reference numeral 20 denotes a slide guide. The socket 1 is axially slidably supported in an oil-free bush 18 press-fitted into the inner peripheral wall of the socket guide 17. The oil-free bush 18 is connected to the centering device 16 via the socket guide 17 and the adapter 41. Installed.

Therefore, the socket 1 is supported by the socket guide 17 and the non-lubricating bush 18, which are the steadying jigs, so that the centering device 16 can correct the horizontal displacement. The base of the main body 2 of the socket is provided with an enlarged diameter portion 2C. The enlarged diameter portion 2C is loosely fitted into the internal space 17A of the socket guide 17 so as to be able to advance and retreat, and is interposed in the internal space 17A. The socket body 2 is urged toward the protruding side by the spring 19 thus set.

The socket body 2 and the spindle 12 are connected by a universal joint 43 and a socket joint 44.
Are connected so as to rotate integrally but to move relative to each other in the axial direction. As shown in FIGS. 12A and 12B, here, the spindle 12 integrally connects a drive shaft (not shown) of the nut runner 11 to the rectangular hole 121, and connects one end of a well-known universal joint 43 to the other end. I do.
The other end of the universal joint 43 is shown in FIG.
The socket joint 44 shown in (a) and (b) is pin-connected. The socket joint 44 includes an enlarged diameter portion 441 and a rod portion 442 having a rectangular cross section extending below the enlarged portion 441. The rod portion 442 is formed with an elongated hole 443 extending in the direction of the axis L. A pin 21 fixed to the socket body 2 side is loosely fitted therein. Thus, the rotational force of the spindle 12 is transmitted to the socket body 2 by the inner peripheral surface of the square hole in the enlarged socket portion 2C that comes into contact with the rod-shaped portion 442 of the socket joint 44. The socket joint 44 can move in the axial direction by an amount corresponding to the length of the hole 443.

Reference numeral 40 denotes a spindle spring whose upper and lower ends are engaged with the enlarged diameter portion 441 and the enlarged diameter portion 2C in a pressed state, whereby the socket body 2 is urged to the projecting side (downward side). Have been. Here, the socket structure of the present automatic nut tightening device will be described in detail. As shown in FIGS.
Bolt guide bracket (hereinafter simply referred to as a bracket) 17 supported by the enlarged socket portion 2C of the socket body 2
And a guide member 45 supported by the bracket 17 and guide member switching means 46 for switching and moving the guide member 45.

As shown in FIGS. 3 to 6 (a) and 6 (b), the socket body 2 has a base portion having an enlarged diameter portion 2C as described above.
A nut holding space 2A is formed at the center of the distal end of the socket body 2 along the axis, and an axial line L is formed at the back of the nut holding space 2A. A nut pusher holding space 2D and a hole 2B having a diameter smaller than that of the nut pusher holding space 2D are formed in a central portion along the axis. As shown in FIG. 4, for example, an outer peripheral surface of a hexagonal nut is formed on the inner peripheral surface forming the nut holding space 2A so as to be easily fitted and formed of a plurality of irregularities capable of transmitting a tightening torque. You.

The slider 3 is inserted movably in the axial direction into a through hole of the slider guide 47 fitted in the hole 2B and the upper end of the nut pusher holding space 2D. The slider guide 47 and the socket main body 2 are connected through a pin 8a, and the upper part of the slider 3 and the socket main body 2 are connected through a pin 8b so as to allow relative movement in the axial direction. That is, an elongated hole 3C extending in the direction of the axis L is formed at the center of the slider 3, and the slider guide 47 is provided in the elongated hole 3C.
And the pin 8 fixed to the socket body 2 side is loosely fitted,
Moreover, a pin 8b is fixed to the upper part of the slider 3, and an elongated hole 3D into which the pin 8b is loosely fitted is formed on the socket body 2 so as to extend in the direction of the axis L.

The distal end of the slider 3 is disposed as desired in the nut holding space 2A, and a projecting arbor 3A is integrally formed on the distal end of the slider 3 as shown in FIG. The arbor 3A (FIG. 16)
A convex curved surface portion 3B is formed at the tip of (a). In addition, the convex curved surface portion 3B of the arbor 3A is provided in FIG.
The tip-shaped nut regulating jig 4 as shown in (b) and (c) and the tip flange 401 are integrally fitted. Here, the nut regulating jig 4 is fitted to the convex curved surface portion 3B, the tip flange 401 is fitted from the other end of the arbor 3A, and then the nut regulating jig 4 and the tip flange 401 are press-fitted. The two are integrated and the nut regulating jig 4 side is swingably held with respect to the convex curved surface portion 3B.

As described above, the nut regulating jig 4 is
The concave curved surface portion 4A as shown in FIG. 4C is formed so as to open upward, and the concave curved surface portion 4A is formed on the convex curved surface portion 3B.
Are mounted so as to be in contact with each other, and are integrated with the tip flange 401, so that the nut regulating jig 4 does not come off from the tip of the slider 3.

Nut holding surfaces 4C and 4D for holding the nut 31 with its axis aligned are formed on the outer periphery and the base end (the upper end in the figure) of the nut regulating jig 4.
The nut holding surfaces 4C and 4D are formed by a tip flange 401 abutting on an end face of the nut 31 and a nut regulating jig 4 fitted into the inner periphery with an appropriate clearance. Is gradually made to coincide with the axis of the nut regulating jig 4, and finally, the tip flange 401 abuts on the end face of the nut 31 so that both axes substantially coincide with each other. Has become.

Further, the tip of the nut regulating jig 4 (in the figure,
At the lower end), the nut 31
A nut direction adjusting surface 4E for aligning the axis of the bolt 32 with the nut 32 is provided. That is, this nut direction adjusting surface 4
When E comes into contact with the distal end surface of the bolt 32, the axis of the nut regulating jig 4 itself is set to substantially coincide with the axis of the bolt 32, and the axis of the nut regulating jig 4 itself is set. Is substantially coincident with the axis of the nut 31, so that the nut 3
The axis of the bolt 1 is aligned with the axis of the bolt 32. The slider spring 5 is provided in the hole 2B of the socket body 2 and urges the slider 3 in a protruding direction (downward in the figure). Further, the pusher spring 6 connects the slider guide 47 and the nut pusher 48, is provided in the nut pusher holding space 2D along the axial direction of the socket body 2, and the nut 31 set in the nut holding space 2A. Is urged in the direction of fastening to the bolt 32, that is, in the protruding direction (downward in the figure).

The pusher spring 6 is weaker than the slider spring 5, that is, assuming that the spring constant of the slider spring 5 is K ₁ and the spring constant K ₂ of the pusher spring 6 is K ₁ > K _2.
Is set to meet. Thus, at the start of the fastening operation, the nut holding surface 4 at the base end of the nut regulating jig 4
When the nut C is in contact with the end face of the nut 31 and the posture of the nut 31 is regulated, after the fastening operation starts, the nut regulating jig 4 is pushed back by the bolt 32 and moves away from the nut 31. The pusher spring 6 exerts an urging force so that the nut 31 moves forward in a desired posture.

As shown in FIG. 15, the nut pusher 7 at the end of the pusher spring 6 is formed in an annular shape so that the urging force of the spring 6 can be transmitted to the nut 31. The nut holding space 2A at the lower end of the socket body 2
As shown in FIG. 4, a magnet 9 for holding a nut 31 is provided on the inner peripheral surface for producing. In this example, a plurality (two) of magnets are arranged at regular intervals so as to surround the nut 31.

The enlarged diameter portion 2C of the socket body 2 is connected at its upper end to an annular main portion 421 of a bolt guide bracket (hereinafter simply referred to as a bracket) 42 via a pair of guide rods 49 extending in the axial direction. The guide rod 49 is connected to the enlarged socket portion 2C via a spacer 491 slidably fitted to the outside of the guide rod 49, and the bracket 42 is moved relative to the socket body 2 by the relative sliding operation of the spacer 491 and the guide rod 49. Can move up and down. Reference numeral 50 denotes a compression spring which is fitted to the socket main body 2 to urge the bracket 42 downward with respect to the enlarged socket portion 2C.

The bracket 42 is slidably fitted to the socket main body 2 and is disposed on the same axis as FIG.
(A), (b) and as shown in FIG.
And a pair of arm portions 422 extending downward therefrom. The bracket 42 includes a guide member 45 and guide member switching means 4 for switching and moving the guide member 45.
6 is supported.

As shown in FIGS. 7A and 7B and FIGS. 8A and 8B, the guide member 45 is formed as a pair of bolt guides 51 having a substantially half cylindrical shape symmetrical to each other. The pair of bolt guides 51 are provided so as to sandwich the socket body 2. The pair of bolt guides 51 each have a cut 511 formed at the center, and each cut 5
11 are fitted to the respective arm portions 422, and the two are connected to each other by the pins 52 oriented in the horizontal direction. Further, a pair of left and right pull spring bolts 53 extending in a direction parallel to the pins 52 are fixed to the upper ends 512 of the pair of bolt guides 51. Here, a pair of left and right extension spring bolts 53 projecting from one bolt guide 51 and a pair of left and right extension spring bolts 53 projecting from the other bolt guide 51 are each provided with a tension spring 54. The pair of bolt guides 51 are urged to rotate around the pins 52. The upper end 51
In the vicinity of 2, a pair of lateral concave portions 516 described later is formed on the left and right.

A substantially hook-shaped guide wall 514 is formed at lower ends 513 of the pair of bolt guides 51. The guide wall 514 of the bolt guide 51 has a substantially half-moon shape when viewed from the front as shown in FIG. Here, when the guide walls 514 of the pair of bolt guides 51 are attached to each other,
A conical concave guide surface cf centering on the nut holding space 2A (centered on the axis L) can be formed, and a bolt through-hole half 515 facing the hole of the nut 31 in the nut holding space 2A is formed at the center thereof. It is formed. Here, the pair of bolt guides 51 that rotate around the pins 52 is a pair of bolt guides 5.
The guide wall 514 of the pair of bolt guides 51 is separated from the guide position P1 (see FIG. 17) where the first guide wall 514 can be formed to form the concave guide surface cf, and the concave guide surface cf is removed from the nut holding space 2A. Retreat position P
2 (see FIG. 19).

The guide member switching means 46 slides the slider 3 against the slider spring 5 as the first urging means, and moves the cam slider 55 to the engagement position Q1 in conjunction with the slide.
(See FIG. 17) and the retreat position Q2 (see FIG. 19), and the pair of bolt guides 51 are switched to the guide position P1 and the retreat position P2. Here, the switching operation can be performed to switch the concave guide surfaces cf of the pair of bolt guides 51 held integrally with the slider 3 so as to divide the cam slider 55 into two and switch to the retreat position P2 which is separated from each other.

Here, a pin 8b is fixed to the upper portion of the slider 3, and the pin 8b passes through the elongated hole 3D and is integrally connected to the pair of left and right cam sliders 55. The pair of cam sliders 55 have a substantially cross shape as shown in FIG.
The left and right ends of the pin 8a are formed at the lower portion (left side in FIG. 9) of the pin 1a with the left and right ends slidably fitted therein.
53 is formed so as to be able to engage with the lateral recess 516 of the pair of bolt guides 51. Here, a stopper 517 is formed in the vicinity of the lower side of the side recess 516 of the pair of bolt guides 51, and the lateral portion 553 comes into contact with the stopper 517, and the engagement position Q1 (FIG. 17).
), The pair of bolt guides 51 is pulled
4 can be held at the guide position P1 (see FIG. 17) against the elastic force of FIG. 4, and when the lateral portion 553 contacts the side recess 516 of the pair of bolt guides 51 and is at the retreat position Q2 (see FIG. 19), Can be held at the retreat position P2 (see FIG. 19) by the elastic force of the pulling spring 54.

The operation of the socket structure of the automatic nut tightening device having the above configuration will be described with reference to FIGS.

In the socket structure of the automatic nut tightening device shown in FIG. 1, when the nut is automatically tightened, the robot 13 moves the nut runner 11 to the supply position of the nut 31 (not shown).
, The nut 31 is set in the nut regulating jig 4 in the nut holding space 2A at the tip of the socket body 2, the pair of bolt guides 51 are switched to the guide position P1 and held, and the nut runner 11 is then moved. It is moved to face the bolt 32.

At this time, a nut regulating jig 4 is provided at the back of the through hole between the bolt through hole half portions 515 of the pair of bolt guides 51.
Holds the nut 31 through the nut holding surfaces 4C and 4D such that the nut 31 substantially matches the axis L. Further, since the nut regulating jig 4 is swingably attached to the tip of the slider 3, the nut 31 set on the nut regulating jig 4 can swing together with the nut regulating jig 4.

When the socket 1 descends while rotating, the tip of the bolt 32 comes into contact with the conical concave guide surface cf of the pair of bolt guides 51 due to the relative displacement of the t between the bolt 32 and the nut 31. I do. At this time, the contact pressure is maintained at an appropriate amount by the elasticity of the compression spring 50.
In particular, the contact between the rotating concave guide surface cf and the bolt 32 generates a position correcting force in a direction to eliminate the relative positional deviation of t. Therefore, when the socket 1 is further lowered, the entire socket 1 is moved and corrected toward the axis L1 of the bolt 32 by the operation of the centering device 16, and the bolt 3
At the time when the relative displacement of t between the nut 2 and the nut 31 is eliminated, the bolt 32 is fitted into the through hole between the bolt through hole half portions 515 as shown in FIG. Nut 3 held substantially coincident with axis L
It faces one hole. At this time, while lowering the socket body 2, the nut-direction adjusting surface 4 E of the nut regulating jig 4 is moved by the urging force of the slider spring 5 to the tip surface 3 of the bolt 32.
Make contact with 2A.

At this time, the axis of the nut regulating jig 4 and the axis of the bolt 32 do not coincide with each other due to the inclination of the bolt 32 (inclination angle β). , Nut direction adjusting surface 4E and tip surface 32A of bolt 32
As a result, the nut regulating jig 4 is securely inclined at the tip of the slider 3, and the axis of the nut regulating jig 4 is surely aligned with the axis L1 of the bolt 32 as shown in FIG. This is done by matching. In this way,
The axis of the nut 31 also coincides with the axis of the bolt 32. At this time, with respect to the displacement between the nut regulating jig 4 and the nut 31 and the bolt 32 toward the upper and lower retreat position P2, the spindle spindle 40 and the slider 3 for urging the socket body 2 itself are urged. Since the slider spring 5 expands and contracts, it is easily permitted.

Then, in this state, the socket main body 2 is driven to rotate, and the nut 31 is screwed into the bolt 32 and engaged. At this time, since the axis of the nut 31 and the axis of the bolt 32 are already aligned, the nut 31 smoothly meshes with the bolt 32 with its rotation. Immediately after this meshing, the bolt 32 screwed to the nut 31 shifts the nut regulating jig 4 and the slider 3 upward by an amount Δα (for example, 2
(See FIG. 19), and the cam slider 55 is moved from the engagement position Q1 to the retreat position Q2 in accordance with the displacement.
Switch to and move. Therefore, it is possible to prevent the guide wall 514 from interfering with the nut 31 when the fastening is further advanced.

Here, at the time of tightening, the axis L of the socket 1 is shifted at an inclination angle β with respect to the axis L1 of the nut 31 and the bolt 32. By forming a shape such that the outer peripheral surface of the square nut can easily fit and transmit the tightening torque even when inclined,
The nut 31 and the bolt 32 can be securely tightened (see FIG. 20). When the tightening proceeds in this manner, the displacement between the nut regulating jig 4 and the nut 31 and the bolt 32 occurs again. Again, this is because the socket 1 can move horizontally through the centering device 16. Permissible.

Thereafter, when the tightening torque reaches the specified value, the rotation of the nut runner 11 is stopped, the robot 13 detaches the nut runner 11 from the bolt 32, and returns to the predetermined standby position.

As described above, in the socket structure of the present automatic nut tightening device, the flat standard bolt and the screw hole at the tip end penetrate (not a cap nut) without using expensive special bolts and nuts. At the beginning of fastening, the displacement of t between the nut 31 and the bolt 32 is eliminated while using the standard nut, and the direction of the nut 31 and the bolt 32 are removed.
And the inclination angle β, which is a deviation from the direction, can be surely matched, and it is possible to reliably prevent nut fastening failure at extremely low cost. Note that FIG.
Shows the difference in the 100% fastening range of the nut between the socket structure of the conventional automatic nut tightening device and the socket structure of the automatic nut tightening device of the present invention. , And the closed circles indicate the results of experiments using this structure.

As shown in the drawing, in the present structure, the fastening range is more than doubled with respect to the angular deviation of the inclination angle β between the nut and the bolt, and particularly, the positional deviation (t deviation in the horizontal direction). , The fastening range is ten times or more. As described above, the experiments confirmed that the present structure can significantly tolerate the positional deviation and the angular deviation between the nut and the bolt. Further, in the present socket structure, the coupling structure to the nut runner 11 side can be configured in exactly the same manner as the conventional socket structure. Therefore, without changing the configuration of the nut runner 11 side, the current socket and the socket having the present structure can be used. The above-described effects can be obtained simply by exchanging the above, which is also advantageous in terms of cost.

FIG. 22 shows a socket structure of an automatic nut tightening device according to another embodiment of the present invention. The socket structure of this automatic nut tightening device is different from the socket structure of FIG. 1 except that a bolt guide 64 as a guide member attached to the socket 1a and a guide member switching means 65 for switching and moving the bolt guide 64 are different. There are many components that are the same as those described above, and here, the same members are denoted by the same reference numerals, and redundant description thereof will be omitted.

As shown in FIG. 22, the socket structure of the automatic nut tightening device is such that the socket 1a is restricted in position by the centering device 16, the adapter 41 and the socket guide 17 mounted on the tip of the nut runner 11, and the nut runner 11 Rotational driving force is received from the spindle 12 mounted at the center of the tip end via the universal joint 43 and the socket joint 44. That is, the socket 1a is supported by the socket guide 17 and the non-lubricating bush 18, which are the steadying jigs, so that the centering device 16 can correct the displacement in the horizontal direction. An enlarged diameter portion 2C is provided at the base of the main body 2 of the socket 1a. The enlarged diameter portion 2C is loosely fitted in the internal space 17A of the socket guide 17 so as to be able to advance and retreat.
The socket body 2 is urged toward the projecting side by the spindle spring 40 interposed in the internal space 17A.

Here, the socket structure of the present automatic nut tightening device will be described in detail.
A socket body 2 similar to that shown in FIG.
A position correction adapter (hereinafter simply referred to as an adapter) 63 is integrally connected to the socket enlarged diameter portion 2C via a spacer 62 with a bolt (not shown). The adapter 63 is shown in FIG.
As shown in FIG. 25 to FIG. 25, a substantially cylindrical shape having a central hole 631 is formed, and the central hole 6 is sequentially formed in the center along the circumferential direction.
31 and a substantially rectangular side hole 632 communicating with the
Notch surface 633 forming a part of the periphery of
Is formed, and a slot 635 adjacent to the base 634 is formed. Moreover, through holes 638 and 639 are formed in the upper and lower annular portions 636 and 637, respectively, to which a shaft 641 of a bolt guide 64 described later is pivotally attached.

The bracket 42 supports a bolt guide 64 as a guide member and guide member switching means 65 for switching and moving the bolt guide 64. The bolt guide 64 is shown in FIGS. 26 (a), (b), (c) and FIG.
7 (a), (b) and (c), the shaft 64
1 and a claw portion 642 bent and extended from its lower end, and formed on the side wall of the claw portion 642 and directed toward the center of the nut holding space (the axis L of the socket 1a) at the guide position P3 (see FIG. 29). And a curved guide surface sf continuously approaching in plan view. Moreover, this curved guide surface sf
Is the axis L of the socket to correspond to the inclination of the bolt 32.
Has an inclination with respect to.

The guide member switching means 65 includes a shaft 64
A cam plate 651 integrally connected to an upper portion of the cam plate 65 by bolts (not shown); a stopper hole 653 formed in a rotating piece 652 of the cam plate 651; a long hole 654 connected to the stopper hole 653; And a pin 8b '(see a two-dot chain line in FIG. 14) on the slider 3 fitted into the elongated hole 654, and a slider spring 5 for urging the slider 3 downward. Here, the slider 3 and the slider spring 5 have the same structure as that of FIG.
The difference is that only the pin 8b 'on the slider 3 is constituted only by one end of the pin 8b.

Since the pin 8b 'extends in the radial direction with respect to the axis L, as shown in FIGS. 27 (a), 27 (b) and 27 (c), the tip of the pin 8b' When the portion 642 is at the guide position P3, it engages with the stopper hole 653, and when the claw portion 642 is at the retreat position P4, it selectively fits into the elongated hole 654.

A pair of spring posts 66 on a long screw are fixed to the base 634. A spring 661 (see FIG. 29) is externally fitted to the pair of spring posts 66, and a push plate 67 is loosely fitted over the pair of spring posts 66 so as to slide freely. To be urged. A rotating piece 652 of the cam plate 651 loosely fitted in the side hole 632 is interposed below the push plate 67, and the push plate 67 rotates the claw 642 on the shaft 641 side to the retreat position P4 side via the cam plate 651. Energize.

Therefore, when the tip of the pin 8b 'is locked in the stopper hole 653 having a bottom, the claw portion 64 is moved by the spring 661 through the push plate 67 and the rotating piece 652.
Even when the second member 2 is biased toward the retreat position P4, as shown in FIG. 29, the rotating piece 652 is locked at the stopper position Q3, and the claw portion 642 is held at the guide position P3. On the other hand, FIG.
As shown in FIG. 7, when the tip of the pin 8b 'faces the elongated hole 654, which is a through hole, from the bottomed stopper hole 653 in accordance with the upward movement of the slider 3, the rotating piece 652 formed by the tip of the pin 8b'. The latched state is released and the spring 641 is displaced to the release position Q4, and the spring 661 rotates the claw portion 642 toward the retreat position P4 via the push plate 67 and the rotating piece 652.

Here, the operation of the socket structure of the automatic nut tightening device having the above configuration will be described with reference to FIGS. In the socket structure of the automatic nut tightening device shown in FIG. 22, in automatically tightening the nut, the robot 13 moves the nut runner 11, sets the nut 31 on the nut regulating jig 4 of the socket body 2, and guides the claw 642. The position is switched to and held at the position P3, and then the nut runner 11 is moved to face the bolt 32. At this time, the nut restricting jig 4 holds the nut 31 deeply behind the claw portion 642 of the bolt guide 64 through the nut holding surfaces 4C and 4D such that the nut 31 substantially matches the axis L.

Here, when the socket 1a descends while rotating, the tip of the bolt 32 comes into contact with the curved guide surface sf of the claw portion 642 of the bolt guide 64 due to the relative displacement of t between the bolt 32 and the nut 31. . At this time, in particular, by the contact between the rotating curved guide surface sf and the bolt 32, the curved guide surface sf continuously approaching toward the center of the nut holding space (the axis L of the socket 1a) is positioned relative to t. A position correcting force in a direction for eliminating the displacement is generated, and the entire socket 1a is moved and corrected to the axial center line L1 side of the bolt 32 by the operation of the centering device 16, so that the relative displacement of the bolt 32 and the nut 31 by t is reduced. At the time of being removed, it faces the hole of the nut 31 held by the nut regulating jig 4 so as to substantially coincide with the axis L.

At this time, while rotating the socket body 2 downward, the urging force of the slider spring 5 causes the nut direction adjusting surface 4 E of the nut restricting jig 4 to move to the tip end surface 32 of the bolt 32.
A, and the axis of the nut 31 is aligned with the axis of the bolt 32. In this state, since the socket body 2 is rotationally driven, the nut 31 is
And mesh with each other. Immediately after the engagement, the bolt 32 screwed to the nut 31 presses and moves the nut regulating jig 4 and the slider 3 upward. According to the displacement, the pin 8 b ′ on the slider 3 continues from the stopper hole 653. 654, the pivot piece is displaced from the stopper position Q3 to the release position Q4, and the claw portion 642 pivots toward the retreat position P4. Therefore, it is possible to prevent the claw portion 642 from interfering with the nut 31 when the tightening is further advanced.

Thereafter, when the tightening torque reaches the specified value, the rotation of the nut runner 11 is stopped, the robot 13 disengages the nut runner 11 from the bolt 32, and returns to the predetermined standby position. Even with such a socket structure of the automatic nut tightening device shown in FIG. 22, the same effect as that of the socket structure shown in FIG. 1 can be obtained, and particularly, the configuration can be simplified. FIG. 32 shows the difference in the fastening range of the nut between the socket structure of the conventional automatic nut tightening device and the socket structure of the automatic nut tightening device of FIG. 22. In FIG. Shows the experimental results of the present structure, and the open circles show the experimental results of the present structure.

As shown in the figure, in the present structure, the fastening range is more than twice as large as the angle deviation of the inclination angle β between the nut and the bolt, and particularly, the positional deviation (t deviation in the horizontal direction). , The fastening range is ten times or more. As described above, the experiments confirmed that the present structure can significantly tolerate the positional deviation and the angular deviation between the nut and the bolt. In each of the above-described embodiments, the nut direction adjusting surface 4E at the tip of the nut regulating jig 4 is brought into direct contact with the tip end surface 32A of the bolt 32, so that the axis of the nut regulating jig 4 is The end of the nut regulating jig 4 does not directly contact the distal end surface 32A of the bolt 32, but the bolt side end surface of the nut 31 directly contacts the distal end surface 32A of the bolt 32. In this manner, the axis of the nut 31 may be directly aligned with the axis of the bolt 32.

In this case, the flange portion 4C constituting the nut holding surface of the nut regulating jig 4 corresponds to the nut direction adjusting surface. A structure in which the nut 6 is omitted and the spring 6 directly contacts the nut 31 is also conceivable. Further, the shape of each component is not limited to that of the present embodiment.

[0061]

As described above, according to the first aspect of the present invention, the centering device can rotate the socket body by moving the socket body in the horizontal direction perpendicular to the axis of the socket body, and the guide member supported by the socket body. By rotating the concave guide surface of the nut, the position of the nut in the nut holding space is corrected in the direction that eliminates the relative displacement between the nut hole and the bolt, and the nut holding surface of the nut regulating jig holds the nut. Align with the axis of the nut regulating jig, and adjust the relative angular deviation by aligning the nut and bolt axes by directly or indirectly contacting the nut direction adjusting surface of the nut regulating jig with the tip of the bolt. The first urging means urges the nut regulating jig toward the bolt, and the second urging means urges the nut toward the bolt. In this manner, the relative position correction and the relative angle shift of the nut and the bolt in the horizontal direction are corrected, and the meshing is reliably performed. In addition, since the guide member moves to the retreat position at the time of tightening after the engagement of the nut and the bolt is established, the nut and the bolt are securely tightened without interference with the guide member. For this reason, the nut and the bolt can be securely engaged with each other and securely tightened without using a standard bolt or a standard nut, thereby causing a large increase in cost.

[0062]

According to a second aspect of the present invention, in the socket structure of the automatic nut tightening device according to the first aspect, in particular, the guide member is formed as a pair of bolt guides. A conical concave guide surface is formed, and the guide member switching means slides the slider against the first urging means, and divides the pair of bolt guides at the guide position into two by dividing the concave guide surface into two parts. Switch to and move to the retreat position to be separated. In this case, a pair of bolt guides
The dividing structure can be simplified, and when the conical concave guide surfaces of the pair of bolt guides at the guide positions rotate together with the socket body, a position correcting force is generated, and the socket body and the pair of bolt guides are shifted. Align the two holes of the nut and bolt with each other so that they are properly engaged. For this reason, the nut and the bolt can be securely engaged with each other and securely tightened without using a standard bolt or a standard nut, thereby causing a large increase in cost.

According to a third aspect of the present invention, in the socket structure of the automatic nut tightening device according to the first aspect, the guide member includes a guide shaft having a claw-shaped portion, and the claw-shaped portion has a nut. A continuous curved guide surface is formed toward the center of the holding space, and the guide member switching means slides the slider against the first urging means to rotate the guide shaft, and the claw-like member at the guide position is formed. The part is switched to the retreat position and moved.
In this case, when the curved guide surface of the claw portion rotates together with the socket body, a position correcting force is generated, the claw portion on the socket body and the guide shaft is displaced, and both the axis of the nut hole and the bolt are aligned. Align and engage properly. For this reason, the nut and the bolt can be securely engaged with each other and securely tightened without using a standard bolt or a standard nut, thereby causing a large increase in cost.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a nut runner that supports a socket structure of an automatic nut tightening device as one embodiment of the present invention.

FIG. 2 is a partially cutaway sectional view of a socket structure of the automatic nut tightening device of FIG. 1;

FIG. 3 is a sectional view showing the inside of the socket body of the socket structure of the automatic nut tightening device of FIG. 1;

FIG. 4 is a front view of the socket body of FIG. 3;

FIG. 5 is a partially cutaway sectional view of only the socket body of the socket structure of the automatic nut tightening device of FIG. 1;

FIG. 6 shows the socket body of FIG. 5, wherein (a) is a plan view,
(B) is a bottom view.

7A and 7B show a bolt guide used in the socket structure of the automatic nut tightening device of FIG. 1, wherein FIG. 7A is a side view and FIG. 7B is a front view.

8A and 8B show a bolt guide used in the socket structure of the automatic nut tightening device of FIG. 1, wherein FIG. 8A is a bottom view and FIG. 8B is a plan view.

9 (a) is a front view and FIG. 9 (b) is a side view showing a cam slider used in the socket structure of the automatic nut tightening device of FIG.

10A and 10B show a bracket used in the socket structure of the automatic nut tightening device of FIG. 1, wherein FIG.
(B) is a side view.

FIG. 11 is a plan view of a bracket used in the socket structure of the automatic nut tightening device of FIG. 1;

12 shows a spindle used in the socket structure of the automatic nut tightening device of FIG. 1, (a) is a side sectional view, and (b) is a plan view.

13A and 13B show a socket joint used in the socket structure of the automatic nut tightening device of FIG. 1, wherein FIG.
(B) is AA sectional drawing.

FIG. 14 is a cutaway side sectional view of a main part of a slider and a nut regulating jig used in the socket structure of the automatic nut tightening device of FIG. 1;

FIG. 15 is a side view of a nut pusher used in the socket structure of the automatic nut tightening device of FIG. 1;

16 (a) is a side view of an arbor, FIG. 16 (b) is a tip flange, and FIG. 16 (c) is a nut regulating jig. It is a principal part notched sectional view of a tool.

FIG. 17 is an operation explanatory view of the socket structure of the automatic nut tightening device of FIG. 1 before meshing;

FIG. 18 is an operation explanatory view of the socket structure of the automatic nut tightening device of FIG. 1 immediately before engagement of the socket structure;

19 is an explanatory view of the operation of the automatic nut tightening device of FIG. 1 when the socket structure is engaged.

FIG. 20 is an explanatory view of the operation of the automatic nut tightening device of FIG. 1 when the tightening of the socket structure is completed.

21 is experimental data of positional shift and angular shift of the socket structure of the automatic nut tightening device of FIG. 1. FIG.

FIG. 22 is a cutaway view of a main part of a socket structure of an automatic nut tightening device as another embodiment of the present invention.

FIG. 23 is a side view of an adapter used in the socket structure of the automatic nut tightening device of FIG. 22.

24 shows the adapter of FIG. 22, (a) is a front view,
(B) is a rear view.

FIG. 25 is a sectional view taken along the line BB of the adapter used in the socket structure of the automatic nut tightening device of FIG. 22.

26A and 26B show a bolt guide used in the socket structure of the automatic nut tightening device of FIG. 22, wherein FIG. 26A is a side view and FIG.
Is a front view, and (c) is a bottom view.

27A and 27B show a cam plate used in the socket structure of the automatic nut tightening device of FIG. 22, wherein FIG. 27A is a front view and FIG.
Is a side view, and (c) is a plan view.

FIG. 28 is an explanatory view of an operation of the automatic nut tightening device of FIG. 22 before engagement of the socket structure.

FIG. 29 is a view on arrow X1 of the socket structure of the automatic nut tightening device of FIG. 28;

30 is an explanatory view of an operation after the socket structure of the automatic nut tightening device of FIG. 22 is engaged.

31 is a view of the socket structure of the automatic nut tightening device of FIG.

FIG. 32 shows experimental data of positional shift and angular shift of the socket structure of the automatic nut tightening device of FIG. 22.

FIG. 33 is a partially cutaway sectional view of a socket structure of a conventional automatic nut tightening device.

FIG. 34 is an enlarged sectional view of a portion C in FIG. 33;

35A and 35B are explanatory diagrams of a conventional nut automatic tightening device in a socket structure, in which FIG. 35A shows a state before the nut is brought into contact with the bolt, and FIG. (C) is a state diagram after tightening the nut to the bolt.

36A and 36B show bolts to be used in the socket structure of the conventional automatic nut tightening device, wherein FIG. 36A is a side view of a standard bolt, and FIG. 36B is a side view of a point difference bolt with a nut guide.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Socket 2A Nut holding space 2 Socket main body 2C Enlarged diameter part 2D Nut pusher holding space 2B Hole 3 Slider 4 Nut regulating jig 4C Nut holding surface 4D Nut holding surface 4E Nut direction adjusting surface 5 Slider spring 6 Pusher spring 8a Pin 8b Pin 8b 'Pin 11 Nut runner 16 Centering device 31 Nut 32 Bolt 42 Bracket 43 Universal joint 45 Guide member 46 Guide member switching means 51 Bolt guide (main part of guide member 45)
Parts name) 55 Cam slider 63 Adapter 64 Bolt guide 642 Claw portion 65 Guide member switching means 652 Rotating piece 651 Cam plate 653 Stopper hole 654 Long hole 66 Spring post 661 Spring 67 Push plate t Displacement P1 Guide position P2 Retreat position L Shaft center Line cf Concave guide surface sf Curved guide surface P1 Guide position P2 Retreat position P3 Guide position P4 Retreat position

Continuation of the front page (56) References JP-A-6-55383 (JP, A) JP-A-6-24830 (JP, U) JP-A-3-44527 (JP, U) (58) Fields surveyed (Int) .Cl. ⁷ , DB name) B23P 19/06 B25B 21/00

Claims (3)

(57) [Claims] 1. A socket structure of an automatic nut tightening device for tightening a nut to a bolt by being rotationally driven while holding the nut, wherein the socket main body having a nut holding space at a tip end thereof is the same as the socket main body. A centering device movably supported in a horizontal direction perpendicular to the axis of the socket body; a conical concave guide surface supported by the socket body via a bracket and centered on the nut holding space; A guide member for generating a position correcting force in a direction that eliminates a relative displacement between the nut hole in the nut holding space and the bolt when the surface comes into contact with the bolt; and a guide member supported by the bracket. The guide member is at the guide position when the nut and the bolt are engaged with each other, and the retracted position is at the time of tightening after the nut and the bolt are engaged. A guide member switching means for switching and moving the slider; a slider disposed in a hole on the back side of the nut holding space and mounted so as to be slidable in the axial direction; and a swingably mounted at the tip of the slider. A nut holding surface for holding the nut with its axis aligned, and a nut direction adjusting surface for directly or indirectly abutting against the tip of the bolt to align the axis of the nut and the bolt. A first urging means for urging the nut regulating jig toward the bolt through the slider; and urging the nut set on the nut regulating jig toward the bolt. And a second urging means. The socket structure of the automatic nut tightening device, comprising: 2. The socket structure for an automatic nut tightening device according to claim 1, wherein said guide member is formed as a pair of bolt guides provided so as to sandwich said socket body, and said guide member is provided at said guide position. A pair of bolt guides form the concave guide surface, and the guide member switching means interlocks with the sliding of the slider against the first urging means, and the concave shape of the pair of bolt guides at the guide position is provided. It is characterized in that the guide surface is divided into two and switched to a retreat position where they are separated from each other. 3. A socket structure for an automatic nut tightening device according to claim 1, wherein said guide member is provided with a guide shaft pivotally supported by said bracket and having a claw-like portion formed at one end thereof, and said claw. The guide portion has a curved guide surface which is continuous toward the center of the nut holding space at the guide position, and the guide member switching means is adapted to slide the slider against the first urging means. The guide shaft is rotated in conjunction therewith, and the curved guide surface at the guide position is switched to the retreat position and moved.