JP2003039258A - Screw eastening apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate such a trouble that a conventional screw fastening apparatus causes sticking of screws and generation of metallic powder because of high speed rotation of a male screw in such a state that the male screw is tightly pressed against a female screw. SOLUTION: In Step 1, a jig 4 rapidly descends until the position just before the male screw 1a comes into contact with the female screw 2a. In Step 2, a male screw part 1 is rotated at a required constant rotational speed, and at the same time, a female screw part 2 descends at a speed that coincides with the axial displacement speed due to the lead of the screw corresponding to the rotational speed of the screw. In Step 3, descent of the female screw part 2 is stopped just after the male screw part 1 has been rotated by 720 deg., and a rotational speed of the male screw part 1 is increased to increase a screw fitting speed of the screws. Thus, the male screw 1a and the female screw 2a are screw-fitted by approaching them to each other at a speed synchronized to the rotational speed of the screw. Therefore, an initial contacting load on both screw surfaces can be reduced, and sticking of the screws and generation of metallic powder can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw fastening device for screwing and fastening a male screw of a male screw component and a female screw of a female screw component.

[0002]

2. Description of the Related Art A conventional screw fastening device will be described with reference to FIG. In the screw fastening device shown in FIG. 2, the female screw J3 of the female screw component J2 fixed by the jig J1 is replaced with the male screw component J2.
4 male screw J5 is screwed in, and male screw part J4
The nut runner J6, which rotates and drives, rotates at high speed with the male screw J5 strongly pressed against the female screw J3.

[0003]

A large preset load for pressing the male screw J5 against the female screw J3 is applied to the nut runner J6 by a spring or the like. For this reason, if the hardness of at least one of the male screw component J4 and the female screw component J2 is low, biting of the screw may occur. Further, even if the hardness of the male screw component J4 and the hardness of the female screw component J2 are high, there is a problem that metal powder is generated due to friction between the screws.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a screw fastening device which does not bite a screw or generate metal powder.

[0005]

[Means for Solving the Problems] [Means for Claim 1] The means for claim 1 is adopted, and a male screw and a female screw are brought close to each other and screwed at a speed synchronized with the rotation speed of the screw. As a result, the initial contact load between the screws can be reduced as much as possible. Further, when the male screw and the female screw are in contact with each other, when the screws rotate relative to each other, the amount of approach between the two parts until the screws match each other is absorbed by the absorbing means. In this way, the initial contact load between the screws can be reduced as much as possible, and the amount of approach between the two parts until the screws match each other in the state where the male screw and the female screw are in contact is absorbed by the absorbing means. This can prevent the screw from biting and the generation of metal powder.

[Means of claim 2] By adopting the means of claim 2, the machine time is shortened by rapidly bringing the male screw component and the female screw component close to each other until just before the male screw and the female screw come into contact with each other. It is possible to improve productivity.

[Means of claim 3] By adopting the means of claim 3, by increasing the rotation speed of the screw after the male screw and the female screw are screwed by a predetermined amount, the machine time can be shortened, and the production It is possible to improve the property.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described using examples and modifications. [Embodiment] An embodiment will be described with reference to FIG. The screw fastening device includes a male screw component 1 having a male screw 1a and a female screw 2
A device for fastening a female screw component 2 having a,
This screw fastening device includes a nut runner 3 for rotationally driving the male screw component 1 and a jig 4 for moving the female screw component 2 in the vertical direction. In addition, nut runner 3
Is for holding the male screw component 1 so that the male screw 1a faces upward, and the jig 4 holds the female screw component 2 so that the female screw 2a faces downward.

A nut runner 3 holding a male screw component 1
Is driven to rotate in the screw fastening direction by an electric motor (not shown), and the rotation speed of this electric motor is controlled by a controller (not shown). The electric motor includes a torque detection sensor and an angle detection sensor, and outputs of the torque detection sensor and the angle detection sensor are input to the control device.

On the other hand, the jig 4 holding the female screw component 2 is vertically driven by a hydraulic cylinder (not shown), and the speed of the hydraulic cylinder is controlled by the controller in the vertical direction. In addition, the hydraulic cylinder is the jig 4
Is provided with a position sensor for detecting the amount of descent of the position sensor, and the output of this position sensor is input to the control device.

A male screw 1a is provided in the middle of the nut runner 3.
When the screws rotate relative to each other while the female screw 2a and the female screw 2a are in contact with each other, both parts 1 that are displaced until the screws match each other,
Absorbing means (not shown) for absorbing the approach amount between the two, specifically, the descending amount of the jig 4 until the screws are matched with each other.
Is provided. Since this absorbing means absorbs the lowering of the male screw component 1 accompanying the lowering of the female screw component 2, it absorbs only the displacement in the vertical direction, and the compression of the compression spring force in the axial direction is relatively weak. A coil spring or a rubber member is used.

The control device controls the rotational speed of the male screw 1a by the above-mentioned electric motor and the vertical speed of the jig 4 by the hydraulic cylinder, and the screw fastening device operates by the control. Next, the operation of the main part of the screw fastening device under the control of the control device will be described. With the female screw component 2 held by the jig 4 and the male screw component 1 held by the nut runner 3 aligned in the axial direction, the screw screwing process is started.

First, in step 1, the jig 4 is rapidly moved by the hydraulic cylinder until just before the male screw 1a and the female screw 2a come into contact with each other (for example, until the distance L between the male screw 1a and the female screw 2a reaches 1 mm). The male screw component 1 and the female screw component 2 are rapidly brought close to each other by lowering. Next, step 2
At the same time, the male screw component 1 is rotated at a predetermined constant speed by the electric motor, and at the same time when this rotation is started,
The jig 4 is lowered at a speed that matches the axial displacement speed of the screw pitch according to the screw rotation speed.

Next, in step 3, the rotation of the electric motor is started and then the downward movement of the female screw component 2 is stopped at the time when the electric motor has rotated 720 degrees, and the rotation speed of the electric motor is further increased.
Increase screwing speed. When the load on the electric motor exceeds a predetermined value, the electric motor is stopped and the screw fastening process is completed. The operation control of step 2 by the control device corresponds to the rotating contact means.

[Effects of the Embodiment] As described above, the male screw 1a and the female screw 2a are synchronized with the screw rotation speed.
Are approached and screwed together. As a result, the initial contact load between the screws can be reduced as much as possible, and the biting of the screws and the generation of metal powder can be prevented. Also, when the male screw 1a and the female screw 2a are in contact with each other, when the screws relatively rotate,
The amount of approach between the parts 1 and 2 until the screws match each other is absorbed by the absorbing means, so that the biting of the screws and the generation of metal powder can be prevented.

Further, since the male screw component 1 and the female screw component 2 are rapidly brought close to each other just before the male screw 1a and the female screw 2a come into contact with each other, the machine time can be shortened and the productivity can be improved. it can. Furthermore, the male screw 1a and the female screw 2a
After screwing a predetermined amount, that is, after rotating the male screw component 1 by 720 degrees, the screwing speed of the screw is increased, so that the machine time can be shortened and the productivity can be improved.

[Modification] In the above embodiment, the male screw component 1 is rotated, but the female screw component 2 may be rotated. In the above-described embodiment, the example in which the female screw component 2 is driven in the axial direction (downward in the embodiment) is shown, but the male screw component 1 may be driven in the axial direction. Further, the male screw component 1 may be arranged on the female screw component 2, and the male screw component 1
The female screw component 2 and the female screw component 2 may be arranged horizontally. In the above embodiment, the male screw component 1 is rotated by 720 degrees to rotate the male screw 1
Although the example in which a and the female screw 2a are screwed together by a predetermined amount is shown, it is sufficient to rotate 360 ° or more after the male screw 1a and the female screw 2a are contacted with each other, and the rotation angle other than 720 ° is set. You may.

[Brief description of drawings]

FIG. 1 is an operation explanatory view of a screw fastening device (embodiment).

FIG. 2 is an operation explanatory view of a screw fastening device (conventional example).

[Explanation of symbols]

1 Male screw parts 1a male screw 2 Female screw parts 2a female screw 3 Nutrunner 4 jigs

Claims (3)

[Claims] 1. A screw fastening device for fastening a male screw component having a male screw and a female screw component having a female screw, the speed being equal to a transition speed of a pitch of the screw according to a rotation speed of the screw. When the male screw and the female screw are brought into close contact with each other to be screwed together, and the male screw and the female screw are in contact with each other, when the screws are rotated relative to each other, the two screws are matched with each other. A screw fastening device provided with an absorbing means for absorbing the amount of approach between the two parts which has been changed during the period. 2. The screw fastening device according to claim 1, wherein the male screw component and the female screw component are provided so as to rapidly approach each other until just before the male screw and the female screw come into contact with each other. And a screw fastening device. 3. The screw fastening device according to claim 1 or 2, wherein after the male screw and the female screw are screwed together by a predetermined amount, the rotation speed of the screw is increased. .