JPH02232119A - High-speed hourglass worm thread cutting lathe - Google Patents

Abstract

PURPOSE:To improve the thread cutting speed of the hourglass worm by regarding the rotational face of the bite of a high-speed thread cutting attachment as a facing tool and fitting it to a hourglass worm thread cutting lathe in such a way as to satisfy required conditions. CONSTITUTION:A bite holder 11 of a high-speed thread cutting attachment is a cylinder for fitting more than one bite 12 and fixed integrally at a holder mount 13 by means of bolts and the like. This holder mount 13 has a pulley groove 14 at its outside and is rotatably supported at a high-speed thread cutting attachment main body 15 through bearings 16. On the other hand, a hole 17 big enough for hourglass worm material 4 to pass through without touching the inner wall is bored inside the holder mount 13. The attachment main body 15 is rotatably supported by two supporting bases 18 through bearings 19. A motor 20 is fitted at the attachment main body 15, and a pulley 21 is mounted at the output shaft of the motor 20. A belt 22 is also mounted at the pulley groove 14 and the pulley 21.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a high speed hourglass worm thread cutting machine.

(Prior art) A drum-shaped worm thread cutting machine, as shown in Fig. 2, swings a flat or double-conical tool 1 around a wheel axis 2 (table rotation center) within a certain angle range (θ in Fig. 2). I was letting it happen. However, this method has the disadvantage of slow processing speed.

Further, a conventional cylindrical worm high-speed thread cutting machine has a high-speed thread cutting attachment 7 attached to a tool mounting base of a thread cutting machine 6 as shown in FIG. As shown in FIG. 4, this high-speed thread cutting attachment 7 is provided with one or more bits 9 on the inner ring of a tool holder 8 that is moved at high speed, and the inner ring is moved at a tilting center 10 of the tool holder according to the advance angle of the worm screw.
It is designed so that it can be tilted around the . As shown in Fig. 5, when a piping tool 12 attached to a tool holder 11 that rotates at high speed eccentrically with respect to the axis of the drum-shaped worm material 4 that rotates at a low speed comes into contact with the outer periphery of the workpiece 4, it cuts a thin piece. Crescent-shaped chips appear intermittently, creating threads. Therefore, even threads with a coarse pitch can be completed with one cut. However, since this is a cylindrical worm thread cutting machine, there is a problem in that it cannot be used with an hourglass-shaped worm.

(Problems to be Solved by the Invention) The present invention aims to increase the thread cutting speed of an hourglass-shaped worm to improve production efficiency.

(Means for Solving the Problems by the Invention) In a drum-shaped worm thread cutting machine in which the movement of the tool relative to the workpiece of the cylindrical worm thread cutting machine is changed from linear motion to rotational motion, the cutter head is replaced with a high-speed thread cutting attachment, and the high-speed thread cutting is performed. Considering the rotating surface of the attachment bit as one surface tool, install the attachment on the thread cutting machine so that the end of the worm shaft and the cutting surface at the tip of the rotating surface are in contact with each other on the common perpendicular line of the worm shaft and wheel axis. It was installed so that the central cross section of the surface included the common perpendicular line, and the central cross section of the rotating surface included the tilting center of the two tool holders.

(Example) An explanation will be given based on FIG. 1. To summarize the present invention, the cutter head 3 of the conventional hourglass-shaped worm thread cutting machine shown in FIG.
is completely replaced with a high-speed thread cutting attachment 7.

First, a known high-speed thread cutting attachment 7 has an external appearance as shown in FIG. 4, and an internal structure as shown in FIG. 1. That is, the cutting tool holder 11 is a cylinder on which one or more cutting tools 12 are attached, and is integrally fixed to a holder mounting base 13 with bolts or the like. This holder mounting base 13 has a pulley groove 14 on the outside, and the high-speed thread cutting attachment body 1
5 via a bearing 16 so as to be rotatable.

On the other hand, inside the holder mounting base 13 is a drum-shaped worm material 4.
The hole 17 is large enough to allow the person to pass through without touching the inner wall. The attachment body 15 has two support stands 1
8 via a bearing 19. A motor 20 is attached to the attachment body 15, a pulley 21 is attached to the output shaft of the motor 20, and a belt 22 is attached to the pulley groove 14 and the pulley 21.

The above is the configuration of the known high-speed thread cutting attachment 7.

In the present invention, such an attachment 7 is attached to a drum-shaped worm thread cutting machine so as to satisfy the following conditions. First, consider the rotating surface of the cutting tool 12 of the high-speed thread cutting attachment 7 as one surface tool, and attach the attachment 7 to the drum-shaped worm thread cutting machine as follows. b) Attach the drum-shaped worm material 4 so that the bottom of the throat of the worm shaft and the cutting surface at the tip of the rotating surface are in contact with each other on the common perpendicular line between the worm shaft and the wheel shaft (Fig. 5).口) Install so that the center cross section of the rotating surface (the surface cut so that the rotating surface is symmetrical) includes the common perpendicular line. c) Make sure that the center cross section of the rotating surface passes through the two tool holder tilting centers 10.

First, in a conventional drum-shaped worm thread cutting machine, the rotation ratio of the tool table on which the worm material 4 and the high-speed thread cutting attachment 7 are placed is set to be equal to a predetermined reduction ratio. Also, the center-to-center distance between the wheel shaft 2 (rotation center of the tool table) and the axis of the worm shaft material 4 is set to a predetermined distance.

Also, the high-speed thread cutting rear attachment main body 15 is tilted about the tool holder tilting center 10 in accordance with the worm throat tooth bottom lead angle, and the motor 20 is rotated. As a result, pulley 21
, the belt 22, and the pulley groove 14, and the holder mounting base l3 and tool holder 11 begin to rotate together.

As a result, the cutting tool 12 forms a rotating surface, and it is as if this rotating surface were replaced with a conventional conical cutter. A threaded surface is cut on the drum-shaped worm material 4 by the thread cutting I11 movement. Thus, the root of the thread surface matches the desired root of the worm thread surface. Further, the thread groove is symmetrical with respect to the center of the groove.

(Effects) In the drum-shaped worm thread cutting machine, which changes the movement of the tool relative to the workpiece in the cylindrical worm thread cutting machine from linear motion to rotational motion, the cutter head is replaced with a high-speed thread cutting attachment, and the cutting tool of the high-speed thread cutting attachment is Considering the rotating surface as one surface tool, install the attachment on the drum-shaped worm milling machine so that the end of the worm shaft and the cutting surface at the tip of the rotating surface touch on the common perpendicular line between the worm shaft and the wheel axis. It was installed so that the central cross section included the common perpendicular line, and the central cross section of the rotating surface passed through the tilting center of the two tool holders.

By doing this, it became possible to perform high-speed thread cutting using a cylindrical worm, even when cutting threads using an hourglass-shaped worm.

[Brief explanation of the drawing]

FIG. 1 shows the main parts of a high-speed drum-shaped worm thread cutting machine according to the present invention. Figure 2 shows a conventional hourglass-shaped worm thread cutting machine. Figure 3) is a conventional cylindrical worm thread cutting machine. Figure 4 (a) is a high-speed thread cutting attachment;
b) is also a side view. FIG. 5 is an explanatory diagram of the cutting principle of a high-speed thread cutting machine. In the figure: 1 flat or double-conical tool 2 wheel shaft 3 cutter head 4 drum-shaped worm material 5 motor 6 thread cutting machine high speed thread cutting attachment tool holder 9 tool tool holder tilting center bi 1 holder 12 tool holder mounting base 14 pulley groove high speed thread cutting Attachment body bearing 17 Hole support 19 Bearing motor 21 Pulley belt bite holder Tilting center or above Applicant Sumitomo Heavy Industries, Ltd. Sub-Attorney Patent Attorney Isamu Ohashi Figure I Figure 2 Article 1 sentence

Claims (1)

[Claims] In the drum-shaped worm thread cutting machine, which changes the movement of the tool relative to the workpiece in the cylindrical worm thread cutting machine from linear motion to rotational motion, the cutter head is replaced with a high-speed thread cutting attachment, and the rotating surface of the bit of the high-speed thread cutting attachment is changed to 1. The attachment is installed on the thread cutting machine so that the bottom of the throat of the worm shaft and the cutting surface at the tip of the rotating surface are in contact with each other on the common perpendicular line between the worm shaft and the wheel axis, and the center cross section of the rotating surface is on the common perpendicular line. A high-speed drum-shaped worm thread cutting machine, characterized in that the central section of the rotating surface passes through the tilting center of the two tool holders.