JP3400229B2 - Perforated plug attaching / detaching device - Google Patents

Description

BACKGROUND OF THE INVENTION [0001] [Technical Field of the Invention The present invention relates to wearing DatsuSo location of perforations plugs used in the manufacture of seamless steel pipe. [0002] Generally, in the production of seamless steel pipes,
Using a piercer mill or the like, a round steel piece is perforated to form a hollow shell. At this time, a plug and a plug bar are used as rolling tools. Plugs are consumables and need to be replaced. Therefore, plug bar is usually connected with plug,
A detachable mechanism that enables separation is provided. The attachment / detachment mechanism requires functions such as easy attachment / detachment of the plug, excellent durability, and low cost. Conventionally, as such a plug attaching / detaching mechanism, one using various types of detachable locking pieces has been used.
JP-A-290118 discloses a simple plug for manufacturing a seamless steel pipe. FIG. 3 shows this, in which the plug 1 and the plug bar 2 are connected. This plug 1 is a plug for manufacturing a shell-shaped seamless steel pipe having a hollow rear end side, and the hollow portion is provided with a female screw 8 screwed with a male screw 7 at the tip of the plug bar 2 on the opening side thereof. A hollow 9 having a larger inner diameter than the diameter of the root of the female screw 8 and a length longer than the length of the female screw 8 is provided at the back. The distal end of the plug bar 2 is a male screw 7 whose first half is screwed with the female screw 8 of the plug 1, and whose second half has a cylindrical shape whose outer diameter is smaller than the crest diameter of the male screw 7 and whose length is longer than the length of the female screw 8. The tip 6 is provided. When the plug 1 is inserted into the plug bar 2, the male screw 7 and the female screw 8 are not engaged, and the plug 1 can freely rotate with respect to the plug bar 2 during rolling. That is, the plug and the plug bar are not screwed together in a fixed state during rolling, but are connected to each other at a portion where the screw portion has passed and there is no screw. The mechanism for attaching and detaching the plug 1 and the plug bar 2 does not require any detachable locking parts such as movable claws and springs. The plug 1 is inexpensive and has excellent performance because it can be manufactured by casting and does not require machining or the like. Japanese Patent Application Laid-Open No. Hei 7-290118 further discloses a robot hand for holding a plug,
An automatic plug changing device including a motor for rotating a robot hand around a plug axis and a slider for moving the robot hand to a plug position is described. [0004] Such a plug has a simple mechanism, is easy to manufacture, and can be easily attached to and detached from a plug bar, and exhibits excellent performance. By the way, as described above, this plug is a casting and the threaded portion is not machined. For this reason, the screw center may not coincide with the center axis of the plug outer diameter, and when measured, this misalignment was as large as 1 mm. In addition, the plug bar is repeatedly heated and cooled during rolling, and bends. Therefore, the misalignment between the plug and the plug bar may be as large as 2 mm or more. [0005] Therefore, the key points in automatically and reliably attaching and detaching the plug to and from the plug bar are, first of all, the plug accuracy due to the low positioning accuracy of the plug bar and the low finishing accuracy of the screw portion of the plug itself. How to solve the misalignment between the bar and the plug. The other is how to start the meshing of the screw well and smoothly perform the meshing or the meshing release until completion. That is, Japanese Patent Application Laid-Open
It has been desired that the automatic plug changing device (plug attaching / detaching device) disclosed in Japanese Patent Application No. -290118 should further facilitate the alignment of the plug with the plug bar. The present invention aims to provide a further improved plug deposition DatsuSo location of this point. SUMMARY OF THE INVENTION The present invention relates to a method for mounting and dismounting a shell-shaped plug for a seamless steel pipe having a cavity having an internal thread on an inlet side to a plug bar. the match, while rotating the plug in the forward or reverse direction, may be advantageously implemented puncture hole plug detachable way to detachable towing from pressing or plug bar in the plug bar
Provide a device that can . [0007] The device of the present invention comprises a guide for supporting the front end of the plug, a clamp for holding the rear end of the plug, a plug rotation device capable of freely changing the plug rotation and torque pattern, and moving the plug back and forth in the axial direction. A punching plug attaching / detaching device characterized by combining a robot hand having a slide to be locked and a slide lock for fixing the slide in a fixed position, and a robot having a floating function for automatically aligning a plug and a plug bar. is there. [0008] The present invention is a plug attachment DatsuSo location that to ensure that they perform in an automatic replacement of the plug as a target plug attachment apparatus of the screw type shown in FIG. First, as a solution to the alignment, a robot having a floating function for performing automatic alignment is applied. The floating function is an automatic centering function that detects the misalignment of two objects when approaching or separating them by mechanical force or the torque of a servomotor, and follows the direction of centering one object. is there. Further, a high-performance robot hand has been developed as a solution to the smooth engagement of the screws. This robot hand has a guide for supporting the front end of the plug and a clamp for holding the rear end of the plug in order to accurately hold the plug. In addition, a plug rotation device that can freely change the rotation and torque pattern of the plug, a slide that moves the plug back and forth in the axial direction, and a slide lock that fixes the slide at a fixed position are provided. Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view of a robot hand of the drilling plug attaching / detaching apparatus according to the embodiment. The guide block 10 for supporting the distal end of the plug 1
In order to center the plug 1, a guide block 10 having a concave conical shape is pressed against the head of the plug 1 by a spring 11 in the axial direction of the plug 1. The clamp for gripping the rear end of the plug 1 includes a plurality of clamp claws 1 for directly gripping the outer periphery of the plug from the outside in the radial direction of the plug.
2. A link arm 13 for supporting the clamp claw 12, a grooved slide block 14 for swinging the link arm 13 in the clamp opening and closing direction, and a clamping cylinder 16 for moving the slide block 14 forward and backward through a slider 15.
It has. When the grooved slide block 14 is propelled forward and backward by the clamping cylinder 16, the groove inclined with respect to the axial direction moves one end of the link arm 13 in the direction perpendicular to the axis, and the link arm 13 Swings around this point of view,
Clamp the plug. This mechanism may use another link mechanism, cam mechanism, or the like. The clamping cylinder 16
The clamp holding the plug 1 can be opened and closed via the above mechanism. [0011] Next, a plug rotation device which can freely change the plug rotation and torque pattern is a plug tip guide 1.
0. The plug 1 is rotated forward and backward by the rotating motor 18 via the gear 17 in the plug rear end clamp. The plug tip guide 10 and the plug rear end clamp are provided in the casing 19.
Is supported via a bearing 20. The rotation motor 18 can freely change the rotation and torque patterns. Since the plug in question is as cast, the screwing or unscrewing torque is not constant. Therefore, the rotary motor 18 incorporates an inverter or a torque converter capable of changing a torque pattern so that the motor operates smoothly even when the torque greatly fluctuates. A slide 22 for moving the plug 1 back and forth in the axial direction moves the casing 19 back and forth by a slide cylinder 21. The casing 19 is connected to a robot mounting bracket 23 via a slide 22. The slide lock for fixing the slide 22 in a fixed position can be performed by allowing a positioning pin 25 attached to a tip of a slide lock cylinder 24 attached to a robot attachment bracket 23 to enter and exit a small hole 26 formed in the casing 19. Has become. Next, the floating function of the embodiment will be described. In the embodiment, the misalignment between the plug and the plug bar is automatically adjusted by controlling the servomotor of each axis of the articulated robot. That is, when the robot hand attaches and detaches the plug 1 and the plug bar 2, if the edge of the hole of the plug 1 and the plug bar 2 come into strong contact due to misalignment, the servo motor shaft on which the reaction torque acts most will avoid this. The plug 1 is operated so as to follow the plug 1 in the direction in which the plug 1 moves. Such a floating function is provided by the plug 1
Only at the time of attaching and detaching the plug bar 2 and the plug bar 2, the control mode of the servo motor of the robot is changed from the position control mode to the torque control mode. 2 and 3 show the shapes of a plug 1 and a plug bar 2 according to an embodiment. Outer diameter of plug 1 is 178mm, weight 40
kg. The clearance between the thread engagement portions of the plug 1 and the plug bar 2 is 0.5 mm to 1.0 mm. The plug is a casting and the thread is not machined. Therefore, the center of the screw center does not always match the outer diameter of the plug. According to actual measurements, the misalignment reached 1 mm. FIG. 2 is a perspective view showing the overall equipment configuration of the embodiment. A robot hand 28 as shown in FIG. 1 is attached to the tip of a 6-axis multi-joint general-purpose robot 27 having a maximum payload of 150 kg.
Is installed. In addition, a floating function is provided. A plug palletizer 29 is prepared so that the plug can be set up in advance. The positioning device for the plug bar 2 includes an aligning device 30 for determining the position of the plug bar in the longitudinal direction, and a bar clamp device 31 for determining the position of the plug bar in the lateral and height directions. The robot 27 selects a robot capable of teaching the self-aligning floating function in a necessary moving range. The necessary movement range here is the time when the plug 1 and the plug bar 2 are attached and detached. Therefore, when the robot 27 transports or moves the plug 1 via the robot hand 28, the automatic alignment floating function is set in a range in which the plug 1 is not taught. The plug bar 2 bends during repeated heating and cooling during rolling. Therefore, even if the bar clamp device 31 is used, the misalignment between the plug 1 and the plug bar 2 may be 2 mm or more. In the embodiment, the automatic alignment of the plug and the plug bar is achieved by adopting a robot having an automatic alignment floating function. Further, it was possible to easily realize the robot hand by combining a commercially available electric nut runner capable of freely changing the plug rotation and the torque pattern. In addition, a commercially available computer was used as a control device, a necessary sequence program was created and applied to the program, and the device of the embodiment could be suitably operated by controlling the robot control device. The apparatus according to the present invention allows the operation of attaching and detaching a piercing plug using a screw-type plug and a plug bar to match the piercing process and incorporate the method of the present invention into its sequence control, thereby enabling automatic operation without human intervention. It has become possible to implement it on a regular basis. For this reason, the advantages of the screw type plug are further enhanced, and the piercing and rolling is greatly contributed. According to the present invention, the replacement of the plug, which has conventionally been performed manually, can be automatically performed. Also,
By automatically changing the plug, the average cycle time of the piercing and rolling could be reduced from 40 seconds to 30 seconds.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional side view of a perforated plug attaching / detaching apparatus according to an embodiment. FIG. 2 is an explanatory diagram of plug attachment / detachment. FIG. 3 is a vertical cross-sectional view of the plug showing engagement between a screw type plug and a plug bar. DESCRIPTION OF SYMBOLS 1 Plug 2 Plug bar 6 Tip 7 Male screw 8 Female screw 9 Cavity 10 Guide block 11 Spring 12 Clamping claw 13 Link arm 14 Slide block with groove 15 Slider 16 Cylinder 17 Gear 18 Motor 19 Casing 20 Bearing 21 Cylinder 22 Slide 23 Bracket 24 Cylinder 25 Positioning pin 26 Small hole 27 Robot 28 Robot hand 29 Plug palletizer 30 Aligning device 31 Bar clamp device

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-7-290118 (JP, A) JP-A-5-57308 (JP, A) JP-A-4-309404 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B21B 25/06

Claims (1)

(57) [Claims] [Claim 1] A guide and a plug for supporting the tip of the plug.
Clamp, plug rotation and torque to grip the rear end
Plug rotation device and plug that can change pattern freely
A slide that moves forward and backward in the axial direction and the slide is in a fixed position
A robot hand equipped with a slide lock that is fixed to the
Floating function to automatically align the plug and plug bar
An attachment / detachment device for a perforated plug, comprising a combination with a robot having