JPS6333966B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a thread cutting attachment for cutting large lead screws by milling in a complex machining NC lathe.

Conventional technology When milling a thread with a large lead on a compound lathe, an attachment is created so that the milling cutter mounting angle matches the lead of the thread, but since it cannot be easily adapted to threads with different leads, each attachment is made specifically for each thread. I had no choice but to become an attachment. In addition, if the lead angle cannot be adjusted to the cutter, or if the lead cannot be perfectly matched, a specially shaped cutter must be used to compensate for the difference, and the cutter itself has to be specially designed. In this way, it is difficult to handle the leads of various workpieces, which requires extra costs for attachments and cutters, and also poses management problems.

Purpose Accordingly, it is an object of the present invention to provide a thread cutting attachment that can be widely adapted to various screw lead angles with a small number of parts.

Solution The present invention provides a tool rest having a drive shaft of a rotary tool of a multi-processing NC lathe with a lower stand that can be rotated and positioned around the drive shaft, and a lower stand that can be rotated and positioned a predetermined amount away from the center of rotation of the lower stand from the drive shaft. An upper table is provided that is rotated and positioned around the rotation axis to which the information is transmitted.
A tool shaft, which is rotated from the rotating shaft and has a groove cutter fixed thereto, is provided on the upper stand so as to be rotatable in a direction perpendicular to the rotating shaft, so that the center of the cutter can always be set on the center line of the main shaft.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings.

A rotary tool of a compound NC lathe (not shown) is attached to one tool mounting surface 2a of a polygonal turret 2, which is indexed by rotation of the turret tool rest 1, which has a drive shaft for rotating the tool.The tool drive has a gear 4 at the tip. A circular receptacle 2b is provided concentrically with the shaft 3, and a lower base 5 with an adjustable turning angle, in which a circular concave portion 5a on the lower surface is fitted, is installed at a plurality of positions around the drive shaft 3. It is fixed to the tool mounting surface 2a with bolts 6 in the arcuate groove 5b. A reference point B1 is engraved on the side surface of the outer periphery 5c of the lower base 5, which forms an arc concentric with the center of rotation, and an angle scale A1 is engraved concentrically with the drive shaft 3 on the mounting surface 2a of the turret 2. The mounting angle can be read by Further, the lower base 5 has a circular concave portion 5d cut therein, which is located a predetermined distance _R1 away from the center of rotation, that is, the center of the drive shaft 3, and has a parallel axis. It is designed to accommodate gears. A circular stopper 7a on the lower surface of the upper table 7 is fitted into this concave portion 5d, and the turning angle can be adjusted.
The upper stand 7 is fixed to the lower stand 5 with bolts 8 in a plurality of arcuate grooves 7b concentric with the center. This upper stand 7 has a gear 10 at the lower end that meshes with the gear 4 by means of a bearing 9 at the center of the spigot 7a, and a bevel gear 1 at the upper end.
An intermediate shaft 12, to which a shaft 1 is fixed, is rotatably supported. Further, a bevel gear 15 that meshes with the bevel gear 11 is fixed to the rear end of the upper stand 7, and a tool shaft 14 whose tip is a collect chuck 16 is rotatably supported by a bearing 13 in a direction perpendicular to the intermediate shaft 12. . Furthermore, a reference point _B2 is engraved on the arcuate outer periphery 7c that is concentric with the intermediate axis 12 of the upper stand 7, and an angle scale is engraved on the upper surface of the lower stand 5 concentrically with the concave portion 5d.
A ₂ is used to read the turning angle. A cutter holder 18 is attached to the collet 16 of the tool shaft 14 and has a grooved cutter 17 fixed to the tip for thread cutting.
is fixed to a predetermined length. A chuck 19 of the main shaft (not shown) of the lathe holds a workpiece W having a pilot hole drilled therein so as to cut, for example, a female thread with a large lead.

Once the workpiece W has been determined, the inclination angle of the groove cutter is determined in accordance with the lead angle of the female thread. That is, when the thread direction is rightward and the desired lead angle is β, the distance from the width center of the groove cutter cutting edge to the center of the intermediate shaft 12 is R ₂ , and the cutter holder is attached to the collet 16 so that this distance is usually constant. 18 is fixed, but it does not necessarily have to be constant, and the actual dimensions are determined by measuring the mounting dimensions. In addition, the distance between the center point of the intermediate shaft 12 and the spindle center line is h, the mounting angle of the lower stand is α with respect to the spindle center line, and similarly the mounting angle of the tool axis is β, that is, the lead angle of the workpiece. Since the distance between the axis 3 and the intermediate shaft 12 is R ₁ , α is determined by h=R ₁ sinα=R ₂ sinβ ∴α=sin ^-1 R ₂ sinβ/R ₁ . Loosen the bolt 6 and remove the lower base 5.
is rotated by α degree clockwise in FIGS. 2 and 4 and fixed to the turret 2 with bolts 6. Next, loosen the bolt 8 and move the upper table 7 counterclockwise to the lead angle β.
Rotate it once and fix it to the lower stand 5 with bolts 8. By doing this, the groove cutter 1 is placed on the center line of the spindle.
The center of 7 can be located. In this embodiment, the lower base of the attachment is attached to one side of the turret, but it can also be attached exclusively to the turret.

Effects As described in detail above, the present invention is a thread cutting device for a compound NC lathe in which an attachment having a double rotation adjustment mechanism for the upper and lower tables is attached to the tool rest, so that the center of the groove cutter is on the center line of the main spindle. Since the cutting position of the cutter can be matched with the lead angle, it is possible to match the lead angle of various screws with widely different leads, making adjustment extremely easy. . Moreover, since the cutter shape can be made to match the groove shape of the cross section at right angles to the groove of the female thread, there is no need to change the cutter shape as long as the groove shape is the same. It can be widely used by simply changing the mounting angle. In addition, it is possible to handle different types of screws by attaching a cutter with a shape that corresponds to the groove shape and adjusting the lead angle. It has the feature that it is extremely simple to manufacture and costs less than those that require complicated processing to find and shape.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the attachment of the present invention installed on a turret tool post, Figure 2 is a plan view of the attachment, Figure 3 is a sectional view taken along the - line in Figure 2, and Figure 4 is adjustment with the workpiece. It is a relationship diagram of later attachments. 2...turret, 3...drive shaft, 5...lower stand,
7... Upper stand, 12... Intermediate shaft, 4, 10... Gear, 11, 15... Bevel gear, 14... Tool shaft, 1
7...Mizo cutlet.

Claims (1)

[Claims] 1. In a complex machining NC lathe that mills screws with large leads, a lower stand that can be rotated around the drive shaft is fixed to a tool post that has a drive shaft of a rotary tool so that the angle can be adjusted, and the rotation center of the lower stand and a predetermined position are fixed. An intermediate shaft that is parallel to the drive shaft and transmits rotation is rotatably supported at a distance apart, and an upper stage that is rotatable around the intermediate shaft is fixed to the lower stage so as to be adjustable in angle, and the upper stage is provided with a groove. A thread cutting attachment for a lathe, characterized in that a cutter is removably fixed and a tool shaft is rotatably supported to transmit rotation in a direction perpendicular to the intermediate shaft.