JP7145828B2 - bolt tightening device - Google Patents

Description

The present invention relates to a bolt tightening device. More specifically, the present invention relates to a bolt tightening device that engages the head of a bolt with a socket by rotating and pressing the socket against the head of a bolt clamped by a chuck mechanism.

A bolt tightening device includes a chuck mechanism that clamps a bolt supplied from a parts feeder in a predetermined posture, and a nut runner that fits the head of the bolt clamped by the chuck mechanism into a socket. Here, since the head of the bolt and the inside of the socket are formed in a polygonal shape (for example, a hexagonal shape), in order to fit the head of the bolt into the inside of the socket, the bolt and the socket must be coaxial. In addition, it is necessary to match the phases of the bolts supplied from the parts feeder, but the phases of the bolts supplied from the parts feeder are not constant. For this reason, the nut runner presses the socket while rotating it against the head of the bolt clamped by the chuck mechanism, thereby fitting the head of the bolt to the socket (see Patent Document 1).

However, if the bolt is not firmly clamped by the chuck mechanism, the bolt may rotate together with the socket when the socket is rotated, resulting in a failure to receive the bolt. Therefore, in the bolt tightening device disclosed in Patent Document 1, one of a pair of chuck members provided to sandwich the bolt is formed with a thread groove portion that engages with the thread portion of the bolt. As a result, the contact area between the chuck member and the bolt can be increased, and the frictional force around the axis between the chuck member and the bolt can be increased, so that the bolt can be prevented from rotating together.

Patent No. 5146392

However, in the bolt tightening device disclosed in Patent Document 1, the smaller the diameter of the bolt, the smaller the contact area between the chuck member and the bolt, which in turn reduces the tightening force of the bolt. Therefore, in the bolt tightening device of Patent Document 1, it is necessary to increase the length of the chuck member along the bolt axis as the bolt diameter becomes smaller.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a bolt tightening device capable of firmly clamping a bolt so as not to co-rotate even with a small contact area.

(1) A bolt tightening device (for example, bolt tightening devices 1 and 1A described later) according to the present invention includes a chuck mechanism (for example, a A chuck mechanism 71 to be described later) and a socket (for example, a socket 81 to be described later) are rotated and pressed against a head portion of the bolt (for example, a head portion 91 to be described later) held by the chuck mechanism. a nut runner (for example, a nut runner 8 to be described later) for fitting the head to the socket, and the chuck mechanism contacts a bolt threaded portion (for example, a bolt threaded portion 92 to be described later) when the bolt is clamped. A first thread portion (for example, a first right-hand thread portion 56 or a left-hand thread portion 46A described later) and a second thread portion (for example, a second right-hand thread portion 57 or a right-hand thread portion described later) that are partial and have the same pitch 56A), wherein the phases of the pitches of the first and second threaded portions are shifted by a predetermined length (for example, a phase shift length α1 or α2, which will be described later) along the bolt axis (for example, the bolt axis O, which will be described later). It is characterized by being provided.

In the present invention, the state in which the phases of the pitches of the first threaded portion and the second threaded portion are aligned means that the first and second threaded portions contact the bolt threaded portion. It means a state in which both the first and second threaded portions are in a relative positional relationship such that they mesh with the bolt threaded portion when the first and second threaded portions are engaged with each other. In other words, the state in which the pitches of the first and second threads are out of phase means that when the first and second threads are brought into contact with the bolt thread, It refers to a state in which there is a relative positional relationship in which neither the first threaded portion nor the second threaded portion meshes with the bolt threaded portion.

A helical thread centered on the bolt axis is formed in the bolt threaded portion with which the first threaded portion and the second threaded portion are in contact. Therefore, when the pitch of the bolt threaded portion and the first and second threaded portions is P, the position of the crest of the bolt threaded portion is θ° (θ is 0 or more 360) travels along the bolt axis by P×(θ/360). More specifically, the position of the top of the thread of the bolt thread advances along the bolt axis by 0.5P when the bolt thread rotates 180° around the bolt axis, and advances along the bolt axis by P when it rotates 360°. proceed along

Therefore, when the first and second threaded portions are provided at positions shifted by θ° around the axis of the bolt, when the phases of the pitches of the first and second threaded portions are aligned, the first threaded portion The distance along the bolt axis between the crest of the thread at and the crest of the thread at the second thread is |(n+(θ/360))×P|. where n is any integer. In other words, with the first and second threads out of phase, the distance along the bolt axis between the crests of the first and second threads is |(n+(θ /360))×P|

Further, when the first and second threaded portions are provided at positions facing each other across the bolt, that is, when θ=180, when the phases of the pitches of the first and second threaded portions are aligned, the first The distance along the bolt axis between the crests of the first and second threads is |(n+0.5)*P|.

Further, when the first and second threaded portions are arranged in a row along the bolt axis, that is, when θ=0, when the phases of the pitches of the first and second threaded portions are aligned, the first The distance along the bolt axis between the crests of the first and second threads is |n×P|.

(2) In this case, the chuck mechanism includes a first chuck member (for example, a left chuck member 4 to be described later) and a second chuck member facing each other along a sandwiching direction (for example, a chucking direction CD to be described later) with the bolt therebetween. A member (for example, a right chuck member 5 to be described later) is provided, and the first and second screw portions (for example, a first right screw portion 56 and a second right screw portion 57 to be described later) are provided in the first chuck member. Spaced apart along the bolt axis. Further, n is a predetermined integer, P is the pitch of the first and second threaded portions, and the bolt between the crest of the first threaded portion and the crest of the second threaded portion is The phase shift length α1 defined by the following equation (1) is preferably greater than 0 and smaller than P, where D1 is the distance along the axis.
α1=|D1−n×P| (1)

(3) In this case, the chuck mechanism includes a first chuck member (for example, a left chuck member 4A to be described later) and a second chuck member facing each other along a sandwiching direction (for example, a chucking direction CD to be described later) with the bolt interposed therebetween. A member (for example, a right chuck member 5A to be described later) is provided, and the first and second threaded portions (for example, a left threaded portion 46A and a right threaded portion 56A to be described later) are provided on the first and second chuck members, respectively. be done. Further, n is a predetermined integer, P is the pitch of the first and second threaded portions, and the bolt between the crest of the first threaded portion and the crest of the second threaded portion is The phase shift length α2 defined by the following equation (2) is preferably greater than 0 and smaller than P, where D2 is the distance along the axis.
α2=|D2−(n+0.5)×P| (2)

(1) The chuck mechanism includes a first threaded portion and a second threaded portion having the same pitch as portions that come into contact with the bolt threaded portion when the bolt is clamped. Further, the first and second threaded portions are provided with their pitch phases shifted by a predetermined length along the bolt axis. Therefore, when the bolt is clamped by the chuck mechanism and the first threaded portion and the second threaded portion are pressed against the bolt threaded portion along the clamping direction, each threaded portion comes into contact with the flank surface on the opposite side. Opposite drag forces are generated along the bolt axis between each threaded portion and the bolt threaded portion. Thus, according to the present invention, even if the contact area between the chuck mechanism and the bolt threaded portion is small, the bolt can be firmly held so as not to rotate together.

(2) The chuck mechanism includes a first chuck member and a second chuck member that face each other along the clamping direction with the bolt therebetween. The first and second threads are spaced apart along the bolt axis on the first chuck member. In addition, in the first threaded portion and the second threaded portion arranged along the axis of the bolt, the phase shift length α1 between the respective threaded portions defined by the above formula (1) is set to be greater than 0 and smaller than P. . Thus, by bringing the first chuck member and the second chuck member closer to each other along the clamping direction, the first threaded portion and the second threaded portion are pressed against the bolt threaded portion along the clamping direction. Opposite drag forces are generated along the bolt axis between the bolt threads. Thus, according to the present invention, even if the contact area between the chuck mechanism and the bolt threaded portion is small, the bolt can be firmly held so as not to rotate together.

(3) The chuck mechanism includes a first chuck member and a second chuck member that face each other along the clamping direction with the bolt therebetween. First and second threads are provided on the first and second chuck members, respectively. In addition, in the first threaded portion and the second threaded portion provided with the bolt interposed therebetween, the phase shift length α2 between the respective threaded portions defined by the above formula (2) is set to be greater than 0 and smaller than P. . Thus, by bringing the first chuck member and the second chuck member closer to each other along the clamping direction, the first threaded portion and the second threaded portion are pressed against the bolt threaded portion along the clamping direction. Opposite drag forces are generated along the bolt axis between the bolt threads. Thus, according to the present invention, even if the contact area between the chuck mechanism and the bolt threaded portion is small, the bolt can be firmly held so as not to rotate together. Further, according to the present invention, the phase shift is achieved by adjusting the spacing along the bolt axis between the first threaded portion provided on the first chuck member and the second threaded portion provided on the second chuck member. The length α2 can be set to a preferred length. Therefore, according to the present invention, standardized products having the same pitch can be used as the first screw portion and the second screw portion, so that the cost of the chuck mechanism can be reduced.

It is a figure showing composition of a bolt tightening device concerning a 1st embodiment of the present invention. It is a figure which shows the state which mutually separated the left claw member and the right claw member along the chuck direction. It is a figure which shows the state which mutually approached the left claw member and the right claw member along the chuck direction. FIG. 4 is a cross-sectional view of the left pawl member, right pawl member and bolt along a plane containing the bolt axis; FIG. 7 is a cross-sectional view along a plane including the bolt axis of the left pawl member, the right pawl member, and the bolt in the bolt tightening device according to the second embodiment of the present invention;

<First Embodiment>
Hereinafter, the configuration of the bolt tightening device 1 according to the first embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing the configuration of a bolt tightening device 1 according to this embodiment. A bolt tightening device 1 clamps one of a plurality of bolts 9 supplied from a parts feeder 2 that supplies a plurality of bolts 9 and a bolts feeder 2, and tightens the bolt 9 to a predetermined tightening point C. A moving bolt moving device 3 and a nut runner 8 provided on the axis of the tightening point C are provided.

Two parallel guide rails 21 and 22 extend between the parts feeder 2 and the bolt moving device 3 . The parts feeder 2 supplies a plurality of bolts 9 to the bolt moving device 3 along these guide rails 21 and 22 . Each bolt 9 supplied from the parts feeder 2 is guided to the tip of the guide rails 21, 22 with its head suspended between the guide rails 21, 22 as shown in FIG.

The bolt moving device 3 clamps the shaft of the bolt 9 at the distal ends of the guide rails 21 and 22, and while clamping the bolt 9, moves the bolt 9 up to the tightening point C defined on the extension line of the guide rails 21 and 22. Moving. The configuration of this bolt moving device 3 will be described later in detail.

The nut runner 8 includes a socket 81 and a nut runner body 82 provided along the bolt axis of the bolt 9 clamped by the bolt moving device 3 at the tightening point C. As shown in FIG. The socket 81 has a cylindrical shape, and a socket hole (not shown) into which the head of the bolt 9 is fitted is formed at the tip of the socket 81 . The nut runner main body 82 presses against the head of the bolt 9 held by the bolt moving device 3 at the tightening point C while rotating the socket 81 around the bolt axis, thereby fitting the head of the bolt 9 into the socket hole of the socket 81. Match the parts.

The bolt moving device 3 includes a left chuck member 4 and a right chuck member 5 which are opposed to each other with guide rails 21 and 22 and a tightening point C interposed therebetween. A stage 6 provided slidably along a movement direction MD orthogonal to CD, a chuck actuator 7C for sliding these chuck members 4 and 5 on the stage 6 along the chuck direction CD, and these chuck members and a moving actuator 7M that slides 4 and 5 on the stage 6 along the moving direction MD.

As shown in FIG. 1, the moving direction MD is parallel to the extending direction of the guide rails 21 and 22 in a horizontal plane orthogonal to the bolt axis of the bolt 9 clamped by the bolt moving device 3 at the tightening point C. is. Further, the chucking direction CD is orthogonal to the extending direction of the guide rails 21 and 22 in the horizontal plane orthogonal to the bolt axis of the bolt 9 clamped by the bolt moving device 3 at the tightening point C.

The stage 6 includes a chuck-direction guide member 61 extending along the chuck direction CD, and a left stage 62 and a right stage 62 provided facing each other across the guide rails 21 and 22 and the tightening point C in the chuck-direction guide member 61 . A stage 64 , a left guide member 63 provided on the left stage 62 , and a right guide member 65 provided on the right stage 64 are provided.

The left stage 62 and the right stage 64 are slidably provided in the chuck direction guide member 61 along the chuck direction CD. The left guide member 63 and the right guide member 65 each extend along the moving direction MD. The left chuck member 4 is provided on the left guide member 63 so as to be slidable along the moving direction MD. The right chuck member 5 is provided on the right guide member 65 so as to be slidable along the moving direction MD. The left chuck member 4 and the right chuck member 5 face each other along the chuck direction CD with the bolt 9 at the tip of the guide rails 21 and 22 interposed therebetween.

The left chuck member 4 includes a left stage 41 slidably provided in the left guide member 63 along the movement direction MD, and a left claw member 42 and a left connecting member 43 fixed to the left stage 41. Prepare.

A threaded portion having the same pitch as that of the bolt threaded portion of the bolt 9 is formed at the tip portion of the left claw member 42 . A guide hole 44 extending along the chuck direction CD is formed in the left connecting member 43 .

The right chuck member 5 includes a right stage 51 slidably provided in the right guide member 65 along the moving direction MD, a right claw member 52 fixed to the right stage 51, a right connecting member 53, and a guide member 51. a roller 54;

A threaded portion having the same pitch as that of the bolt threaded portion of the bolt 9 is formed at the tip portion of the right claw member 52 . The right connecting member 53 is connected to the tip of a rod 55 extending along the moving direction MD from the moving actuator 7M.

The guide roller 54 is provided in the guide hole 44 of the left connecting member 43 so as to be rotatable around the rotary shaft provided on the right stage 51 . As a result, the left chuck member 4 and the right chuck member 5 are integrally slid along the movement direction MD, or the left chuck member 4 and the right chuck member 5 are moved toward or away from each other along the chuck direction CD. It is possible to let

The chuck actuator 7C slides the left stage 62 and the right stage 64 along the chuck direction guide member 61, and moves the left chuck member 4 and the right chuck member 5 toward each other along the chuck direction CD. The threaded portion of the bolt 9 can be sandwiched between the pawl member 42 and the right pawl member 52 . Further, the chuck actuator 7C slides the left stage 62 and the right stage 64 along the chuck direction guide member 61, and separates the left chuck member 4 and the right chuck member 5 from each other along the chuck direction CD. The left pawl member 42 and the right pawl member 52 can be separated from the threaded portion of the bolt 9 .

The movement actuator 7M can advance and retreat the left chuck member 4 and the right chuck member 5 along the movement direction MD by moving the rod 55 forward and backward along the movement direction MD.

Therefore, by jointly using the chuck actuator 7C and the moving actuator 7M, the bolt 9 is sandwiched between the left claw member 42 and the right claw member 52 at the tips of the guide rails 21 and 22, and the bolt 9 is held by the left claw. It can be moved to the tightening point C while being sandwiched between the member 42 and the right claw member 52 .

In the bolt moving device 3 as described above, the chuck mechanism 71 that clamps the bolt 9 supplied to the tip of the guide rails 21 and 22 is operated by the left chuck member 4, right chuck member 5, stage 6, and chuck actuator 7C. Configured. In the bolt moving device 3, the moving mechanism 72 for moving the bolt 9 clamped by the chuck mechanism between the tip portions of the guide rails 21 and 22 and the tightening point C includes the left chuck member 4 and the right chuck member 5. , a stage 6, and a moving actuator 7M.

Next, the configurations of the left claw member 42 and the right claw member 52 will be described in detail with reference to the drawings.

2 and 3 are perspective views showing the configuration of the distal end portions of the guide rails 21 and 22 and the vicinity thereof in the bolt tightening device 1. FIG. FIG. 2 shows a state in which the left claw member 42 and the right claw member 52 are separated from each other along the chucking direction CD, and FIG. Shown close to each other.

The left claw member 42 and the right claw member 52 are provided at positions facing each other along the chuck direction CD with the bolt 9 interposed therebetween at the distal end portions of the guide rails 21 and 22 . Further, the upper surfaces 421, 521 of the left claw member 42 and the right claw member 52 are lower than the head 91 of the bolt 9 and the guide rails 21, 22 supporting it. Recessed grooves 422 and 522 extending along the bolt axis of the bolt 9 are formed in the centers of the tip portions of the left claw member 42 and the right claw member 52, respectively. Further, the width of these grooves 422 and 522 along the moving direction MD is shorter than the nominal diameter of the bolt threaded portion 92 of the bolt 9 .

Therefore, when the left claw member 42 and the right claw member 52 are brought closer to each other along the chucking direction CD, the left claw member 42 moves the bolt 9 at the first contact portion 423 and the second contact portion 424 on both sides of the groove portion 422 . The right claw member 52 contacts the bolt threaded portion 92 at the first contact portion 523 and the second contact portion 524 on both sides of the groove portion 522 . The first contact portion 423 of the left claw member 42 and the second contact portion 524 of the right claw member 52 face each other with the bolt axis O interposed therebetween. The 1 contact portion 523 faces the bolt axis O on both sides. The contact portions 423 and 424 of the left claw member 42 and the contact portions 523 and 524 of the right claw member 52 are formed with threads having the same pitch as the bolt thread portion 92, respectively.

4 is a cross-sectional view of left pawl member 42, right pawl member 52, and bolt 9 along line IV-IV in FIG. More specifically, FIG. 4 is a sectional view along a plane including the second contact portion 424, the first contact portion 523, and the bolt axis O of the left claw member 42, the right claw member 52, and the bolt 9. be.

As shown in FIG. 4 , the second contact portion 424 of the left claw member 42 is formed with a left threaded portion 46 having a pitch equal to the pitch P of the bolt threaded portion 92 . On the other hand, the first contact portion 523 of the right claw member 52 is formed with a first right screw portion 56 and a second right screw portion 57 having pitches equal to the pitch P of the bolt screw portion 92 . The first right-hand threaded portion 56 and the second right-handed threaded portion 57 are spaced apart along the bolt axis O. As shown in FIG.

As shown in FIG. 4, the first right-hand threaded portion 56 and the second right-handed threaded portion 57 each have the same pitch as the pitch P of the bolt threaded portion 92, but the phase of each pitch is along the bolt axis O. are shifted by a phase shift length α1.

More specifically, n is a predetermined integer, P is the pitch of the first right-hand threaded portion 56 and the second right-handed threaded portion 57, and the crest of the first right-handed threaded portion 56 and the second right-handed threaded portion 57 The pitch between the first right-hand threaded portion 56 and the second right-handed threaded portion 57 defined by the following formula (3), where D1 is the distance along the bolt axis O between the crest of the thread at is greater than 0 and less than P.
α1=|D1−n×P| (3)

By shifting the phase between the first right-hand threaded portion 56 and the second right-handed threaded portion 57 as described above, the left claw member 42 and the right claw member 52 are moved in the chucking direction CD as shown in FIG. , and the bolt 9 is sandwiched between the left claw member 42 and the right claw member 52, the first right threaded portion 56 and the second right threaded portion 57 are aligned with the flanks of the bolt threaded portion 92 on the opposite side. It touches the surfaces 93,94. FIG. 4 shows a case where the first right-hand threaded portion 56 is in contact with the tip-side flank surface 93 on the tip side of the bolt, and the second right-handed thread portion 57 is in contact with the head-side flank surface 94 on the head 91 side. .

Therefore, by bringing the left claw member 42 and the right claw member 52 closer to each other along the chuck direction CD, the left screw portion 46 and the right screw portions 56 and 57 are pressed against the bolt screw portion 92 along the chuck direction CD. 4, opposite forces F1 and F2 are generated along the bolt axis O between the first right-hand threaded portion 56 and the second right-handed threaded portion 57 and the bolt threaded portion 92, respectively. More specifically, in the example of FIG. 4, a reaction force F1 directed toward the bolt tip side is generated from the tip side flank surface 93 to the first right-hand threaded portion 56 along the bolt axis O, 2 A drag force F2 directed toward the head portion 91 is generated along the bolt axis O to the right-hand threaded portion 57 . These drag forces F1 and F2 are opposite to each other and increase in proportion to the force pressing the right-hand threaded portions 56 and 57 . Therefore, a frictional force proportional to the force pressing the right-hand threaded portions 56, 57 is generated between the flank surfaces 93, 94 of the bolt threaded portion 92 and the right-handed threaded portions 56, 57. Even if the contact area with the threaded portion 92 is small, the bolt 9 can be firmly held so as not to rotate together.

Although illustration and detailed description are omitted, the first contact portion 423 of the left claw member 42 is formed with a left screw portion having the same pitch as the left screw portion 46 . In addition, the pitch phase between the left-hand threaded portion formed in the first contact portion 423 and the left-hand threaded portion 46 formed in the second contact portion 424 is aligned. The second contact portion 524 of the right claw member 52 includes a first right-hand threaded portion having the same pitch as the first right-handed threaded portion 56 and a second right-handed threaded portion having the same pitch as the second right-handed threaded portion 57 . A threaded portion is spaced apart along the bolt axis O. As shown in FIG. In addition, the phases of the pitches between the first right-handed threaded portion formed on the second contact portion 524 and the first right-handed threaded portion 56 formed on the first contact portion 523 are aligned. The phase of the pitch between the formed second right-hand threaded portion and the second right-handed threaded portion 57 formed in the first contact portion 523 is also aligned. Therefore, when the bolt 9 is sandwiched between the left claw member 42 and the right claw member 52, the first right screw portion and the second right screw portion in the second contact portion 524 of the right claw member 52 and the bolt screw portion 92 are Opposite drag forces are also generated along the bolt axis O in between. Therefore, even if the contact area between the chuck members 4 and 5 and the bolt threaded portion 92 is small, the bolt 9 can be firmly held so as not to rotate together.

<Second embodiment>
Next, the configuration of a bolt tightening device 1A according to a second embodiment of the present invention will be described in detail with reference to the drawings. A bolt tightening device 1A according to this embodiment differs from the bolt tightening device 1 according to the first embodiment in the configuration of the left claw member 42A of the left chuck member 4A and the right claw member 52A of the right chuck member 5A. In the following description of the bolt tightening device 1A, the same components as those of the bolt tightening device 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 5 is a cross-sectional view of the left pawl member 42A, the right pawl member 52A, and the bolt 9 along line IV-IV in FIG. More specifically, FIG. 5 is a cross-sectional view along a plane including the second contact portion 424A, the first contact portion 523A, and the bolt axis O of the left claw member 42A, the right claw member 52A, and the bolt 9. be.

As shown in FIG. 5, a left threaded portion 46A having a pitch equal to the pitch P of the bolt threaded portion 92 is formed on the second contact portion 424A of the left claw member 42A. A right threaded portion 56A having a pitch equal to the pitch P of the bolt threaded portion 92 is formed in the first contact portion 523A of the right claw member 52A.

As shown in FIG. 5, the left-hand threaded portion 46A and the right-handed threaded portion 56A each have the same pitch as the pitch P of the bolt threaded portion 92, but the phase of each pitch is shifted along the bolt axis O by a length of phase shift. They are provided with a shift of α2.

More specifically, n is a predetermined integer, P is the pitch of the left-hand threaded portion 46A and the right-handed threaded portion 56A, and the distance between the crest of the left-handed threaded portion 46A and the crest of the right-handed threaded portion 56A is D2 is the distance along the bolt axis O, the phase shift length α2 of the pitch between the left threaded portion 46A and the right threaded portion 56A defined by the following equation (4) is greater than 0 and smaller than P.
α2=|D2−(n+0.5)×P| (4)

As described above, by shifting the phase between the left threaded portion 46A and the right threaded portion 56A, as shown in FIG. When the left claw member 42A and the right claw member 52A are brought close to each other and the bolt 9 is sandwiched between them, the left threaded portion 46A and the right threaded portion 56A are in contact with the flank surfaces 93 and 94 of the bolt threaded portion 92 on the opposite side, respectively. . 5 shows a case where the left threaded portion 46A is in contact with the tip side flank surface 93 and the right threaded portion 56A is in contact with the head side flank surface 94. As shown in FIG.

Therefore, when the left screw portion 46A and the right screw portion 56A are pressed against the bolt screw portion 92 along the chuck direction CD by bringing the left claw member 42A and the right claw member 52A closer together along the chuck direction CD, As shown in FIG. 5, between the left threaded portion 46A and the right threaded portion 56A and the bolt threaded portion 92, opposite forces F1 and F2 are generated along the bolt axis O, respectively. More specifically, in the example of FIG. 5, a drag force F1 directed toward the head 91 is generated from the head side flank surface 94 to the left threaded portion 46A along the bolt axis O, and the force from the tip side flank surface 93 to the right threaded portion A drag force F2 directed toward the tip end of the bolt is generated along the axis O of the bolt to 56A. These drag forces F1 and F2 are opposite to each other and increase in proportion to the force pressing the left threaded portion 46A and the right threaded portion 56A. Therefore, a frictional force proportional to the force pressing the left screw portion 46A and the right screw portion 56A is generated between the flank surfaces 93 and 94 of the bolt screw portion 92 and the left screw portion 46A and the right screw portion 56A. Even if the contact area between the members 4A, 5A and the bolt threaded portion 92 is small, the bolt can be firmly held so as not to rotate together.

Although illustration and detailed description are omitted, a left screw portion having the same pitch as the left screw portion 46A is formed in the first contact portion of the left claw member 42A. The formed left-hand threaded portion and the left-handed threaded portion 46A formed in the second contact portion 424A are in phase with each other in pitch. A second contact portion of the right claw member 52A is formed with a right-hand thread portion having the same pitch as the right-hand thread portion 56A. The phase of the pitch between the contact portion 523A and the right-hand thread portion 56A is the same. Therefore, when the bolt 9 is sandwiched between the left claw member 42A and the right claw member 52A, the left screw portion at the first contact portion of the left claw member 42A and the right screw portion at the second contact portion of the right claw member 52A are formed. Opposite drag forces are generated along the bolt axis O between . Therefore, even if the contact area between the chuck members 4A, 5A and the bolt threaded portion 92 is small, the bolt 9 can be firmly held so as not to rotate together.

According to the bolt tightening device 1A according to the present embodiment, along the bolt axis O between the left threaded portion 46A provided on the left claw member 42A and the right threaded portion 56A provided on the right claw member 52A, By adjusting the spacing, the phase shift length α2 can be set to a desired length. Therefore, according to the bolt tightening device 1A, standard products having the same pitch can be used as the left threaded portion 46A and the right threaded portion 56A, so that the cost of the chuck members 4A and 5A can be reduced.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to this. Detailed configurations may be changed as appropriate within the scope of the present invention.

1, 1A... bolt tightening device 3... bolt moving device 4, 4A... left chuck member (chuck mechanism)
42, 42A... Left claw member 423... First contact part 424, 424A... Second contact part 46... Left screw part 46A... Left screw part (first screw part)
5, 5A... right chuck member (chuck mechanism)
52, 52A... Right claw member 523, 523A... First contact part 524... Second contact part 56... First right screw part (first screw part)
56A... Right-hand threaded portion (second threaded portion)
57 … Second right-hand threaded portion (second threaded portion)
6... Stage (chuck mechanism)
7C... Chuck actuator (chuck mechanism)
7M... Moving actuator C... Tightening point 71... Chuck mechanism 72... Moving mechanism 8... Nut runner 81... Socket 9... Bolt 91... Head 92... Bolt threaded portion 93... Tip side flank surface 94... Head side flank surface

Claims (2)

A chuck mechanism for clamping a bolt supplied to a predetermined position by bringing a first chuck member and a second chuck member, which are opposed to each other along the clamping direction while clamping the bolt, closer to each other along the clamping direction. When,
A bolt tightening device comprising a nut runner that engages the head of the bolt with the socket by rotating and pressing the socket against the head of the bolt held by the chuck mechanism,
The first chuck member includes a first threaded portion and a second threaded portion which are portions in contact with the bolt threaded portion when the bolt is clamped and which have the same pitch,
the first and second threaded portions are spaced apart along the bolt axis in the first chuck member;
The second chuck member includes a third threaded portion that contacts the bolt threaded portion when the bolt is clamped and has the same pitch as the bolt threaded portion,
Let n be a predetermined integer, P be the pitch of the first and second threaded portions, and the bolt axis between the crest of the first threaded portion and the crest of the second threaded portion is By setting the phase shift length α1 defined by the following equation (1) to be larger than 0 and smaller than P, where D1 is the distance along the first and second chuck members opposite drag forces along the bolt axis between the bolt thread and the first thread and between the bolt thread and the second thread, respectively. A bolt tightening device characterized in that
α1=|D1−n×P| (1) A chuck mechanism for clamping a bolt supplied to a predetermined position by bringing a first chuck member and a second chuck member, which are opposed to each other along the clamping direction while clamping the bolt, closer to each other along the clamping direction. When,
A bolt tightening device comprising a nut runner that engages the head of the bolt with the socket by rotating and pressing the socket against the head of the bolt held by the chuck mechanism,
The first and second chuck members each have a first threaded portion and a second threaded portion which are portions in contact with the bolt threaded portion when the bolt is clamped and have the same pitch,
Let n be a predetermined integer and P be the pitch of the first and second threads along the bolt axis between the crest of the first thread and the crest of the second thread. When the distance between the first and second chuck members is D2, the phase shift length α2 defined by the following equation (2) is set to be larger than 0 and smaller than P so that the first and second chuck members are moved along the clamping direction. When the bolts are brought close to each other and clamped, opposite forces are generated along the bolt axis between the bolt threaded portion and the first threaded portion and between the bolt threaded portion and the second threaded portion. A bolt tightening device characterized by:
α2=|D2−(n+0.5)×P| (2)

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