JP2545591Y2 - Straight shank tap - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a straight shank tap used by being attached to a tapping machine or the like.

[0002]

2. Description of the Related Art A straight shank tap having a shank provided with a non-circular engaging portion at an end of a straight portion having a cylindrical shape, and a screw portion provided with a male screw having a shape corresponding to a female screw to be formed. Are widely used as internal thread processing tools. Such a straight shank tap is generally used by being attached to a main shaft of a tapping machine or the like via a holder. As a method of holding the straight shank tap, the shank is inserted into a mounting hole of the holder and a non-circular engagement portion is provided. Is normally engaged with a rotation drive unit provided at the bottom of the mounting hole with a slight play so as not to be relatively rotatable, and the straight portion is positioned and gripped by a collet chuck. The tap is rotated about the axis by rotating the rotation drive unit together with the collet chuck, but the driving torque at the time of tapping is changed from the rotation drive unit engaged with the relative rotation impossible to the engagement unit. The collet chuck positions the tap concentrically to prevent runout and slipping out of the holder.
Further, by feeding the lead relatively to the workpiece while rotating the tap in this way, a female screw is machined into the prepared hole provided in the workpiece by the screw portion.

[0003]

By the way, in such a tapping, misalignment between the pilot hole and the tap, fluctuation of the rotation, error in lead feed relative to the rotation speed of the tap,
When the tap is pulled backwards from the female screw after tapping, the backlash caused by the backlash causes the synchronization deviation between the start of reverse rotation and the start of reverse feed, etc., while the tap is positioned and held by the holder in a fixed position. Because
There is a problem that the machining accuracy of the female screw is reduced due to the misalignment and the feed error, and an excessive force is applied to the tap to shorten the tool life. On the other hand, there is a tapping machine that allows the tap axis to follow the axis of the pilot hole by the guide action of the tap itself, and that the tap is screwed into the pilot hole according to the lead of the tap. In this case, a complicated mechanism is required to allow the holder holding the tap to be fixed in position in the radial direction and the axial direction of the tap axis, and the apparatus becomes large and expensive. there were.

The present invention has been made in view of the above circumstances, and its purpose is to absorb misalignment between a tap and a pilot hole and a feed error without using a complicated mechanism. The object of the present invention is to improve the processing accuracy of the female screw and the life of the tap.

[0005]

In order to achieve the above object, the present invention is directed to a shank having a non-circular engaging portion at the end of a cylindrical straight portion and a female screw to be formed. And a screw portion provided with a male screw having a shape to be formed, and in a state where the straight portion is positioned and gripped by the holder, a rotational force is applied from the holder via the engaging portion to rotate the shaft around the axis. In a straight shank tap for processing a female screw by the screw portion in a pilot hole provided in the workpiece by being lead-fed relatively to the workpiece, (a)
An elastic member that can be elastically deformed is provided on the outer peripheral portion of the straight portion.
(B) the engaging portion is provided with an elastic member
The tap is displaced relative to the holder
A slight play on the holder to allow
So that it can be engaged with relative rotation
It is characterized by becoming .

[0006]

In such a straight shank tap, since an elastic member which can be elastically deformed is provided on the outer peripheral portion of the straight portion positioned and held by the holder, when a load is applied to the tap when the tap is set up,
By the elastic deformation of the elastic member, the tap can be relatively displaced within a predetermined range with respect to the holder, and the misalignment between the tap and the pilot hole, a feed error, and the like are favorably absorbed. Specifically, for the misalignment and inclination of the pilot hole and the tap, and for the runout of rotation, the misalignment and inclination are alleviated by displacing the tap in a direction perpendicular to the axis, With respect to the lead feed error or the synchronization shift with respect to the rotation, the feed error and the like are reduced by displacing the tap in the axial direction. As a result, a high-precision internal thread with little ridge or the like can be machined, and chipping or breakage of the tap is reduced, thereby extending the tool life. Also, there is an advantage that vibration, noise, and the like generated at the time of tapping are reduced by the elastic deformation of the elastic member.
The engaging portion provided at the end of the straight portion is slightly
The tap can be relatively non-rotatably engaged with the holder, so that the relative displacement of the tap with respect to the holder is allowed. Is transmitted.

[0007]

As described above, according to the straight shank tap of the present invention, the misalignment and the feed error between the tap and the pilot hole are favorably absorbed by the elastic member. Without the use of complex mechanisms that allow the core to float in the radial and axial directions,
The working accuracy of the female screw and the life of the tap can be improved, and vibration, noise, and the like generated at the time of tapping can be reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a straight shank tap 10 according to an embodiment of the present invention (hereinafter simply referred to as tap 10).
Is a front view as viewed from a direction perpendicular to the axis. The tap 10 includes a shank 12 and a threaded portion 14. The threaded portion 14 is provided with a male thread 16 having a thread shape corresponding to a female thread to be formed.
A cutting edge 20 is formed by providing the straight groove 18 and dividing the male screw 16. Shank 12
A straight portion 22 having a cylindrical cross section and an engaging portion 24 having a substantially square cross section provided integrally with an end of the straight portion 22 are provided with a soft outer peripheral portion. Of the elastic member 26 is provided. The tap body is made of high-speed tool steel or cemented carbide, and a portion corresponding to the straight portion 22 of the tap body has a slightly smaller diameter.
6 is provided with a thickness of about 0.5 to 2.0 mm.
The elastic member 26 is made of, for example, an oil-resistant plastic such as polyurethane resin or neoprene rubber or a synthetic rubber. The elastic member 26 previously formed into a cylindrical shape is fitted to the tap main body, or is attached to the adhesive. It is provided on the tap body in a non-removable manner by bonding the resin material or rubber material.

The tap 10 is used by being attached to a spindle such as a tapping machine via a holder.
FIG. 2 shows an example of such a holder. The holder 28 includes a driving piece 32 fixedly mounted on a holder body 30 and the driving piece 32.
And a collet chuck 34 disposed at the same position. The driving piece 32 has an accommodation hole 36 formed in the axis thereof for accommodating the engaging portion 24.
A screw hole is provided so as to be orthogonal to
8 are screwed so as to face each other. The screwing amount of the pair of setscrews 38 is adjusted in advance so that the distance between the tip portions thereof is slightly larger than the width of the engaging portion 24. It is engaged with relative play in a state with slight play. The collet chuck 34 includes a cylindrical member 40 having a tapered hole fixed to the driving piece 32 and a collet 4 fitted into the tapered hole of the cylindrical member 40 with an outer peripheral surface having a tapered shape.
2 and the collet 4 by being screwed into the cylindrical member 40.
2 into the tapered hole. The collet 42 has a plurality of slits formed in the axial direction and can be reduced in diameter.
The diameter is reduced by being pushed into the tapered hole of the cylindrical member 40, and the straight portion 22 of the tap 10 previously inserted into the collet 42 is concentrically positioned and gripped.

FIG. 2 shows a state in which the tap 10 is held by the holder 28, and the tap 10 is attached to the holder 28 with a gap between the engaging portion 24 and the bottom of the receiving hole 36. When the holder 28 is driven to rotate together with the main shaft, the tap 10 is also driven to rotate around its axis, and in this state, the lead 10 is fed relative to the workpiece, thereby providing the tap 10 with the workpiece. The internal thread is cut into the prepared hole by the screw portion 14. The driving torque at the time of this tapping is a pair of set screws 38 of the driving piece 32.
The collet chuck 34 mainly positions the tap 10 concentrically and prevents the tap 10 from slipping out of the holder 28.

At the time of tapping, there is misalignment or rotational fluctuation between the pilot hole and the tap 10, an error in lead feed with respect to the rotation speed of the tap 10, and a reverse rotation for removing the tap 10 from the female screw after tapping. Although it is unavoidable that the synchronization between the start of reverse rotation and the start of reverse feed due to backlash at the time of rotation is inevitable, the tap 10
A soft elastic member 26 is provided on the outer peripheral portion of the straight portion 22 which is positioned and held by the holder 28, and the tap 10 is moved by the elastic deformation of the elastic member 26.
Can be relatively displaced within a predetermined range, so that misalignment between the tap 10 and the pilot hole, a feed error, and the like are favorably absorbed. For example, when the tap 10 is displaced in a direction perpendicular to the axis, the misalignment, the inclination, and the like are alleviated with respect to the misalignment, the inclination, and the runout of rotation between the pilot hole and the tap 10. The tap 10 is displaced in the axial direction with respect to the lead feed error and the synchronization shift with respect to, so that the feed error and the like are alleviated. As a result, a high-precision internal thread with little ridge and the like can be machined, and chipping or breakage of the tap 10 is reduced, thereby extending the tool life. Further, there is an advantage that vibration, noise, and the like generated at the time of tapping can be reduced by the elastic deformation of the elastic member 26.

The engaging portion 24 provided at the end of the straight portion 22 is engaged with the set screw 38 with slight play so as to be relatively non-rotatable, while the tap 10 is accommodated in the engaging portion 24. Since the holder 28 has a gap with the bottom of the hole 36, the tap 10 with respect to the holder 28 is
The relative displacement of
Even if 0 is displaced relative to the holder 28, the rotational force is reliably transmitted through the engaging portion 24.

As described above, according to the tap 10 of the present embodiment, the misalignment with respect to the prepared hole, the feed error, and the like are favorably absorbed by the elastic member 26. Without using a complicated mechanism that allows free movement in the radial and axial directions, the machining accuracy and tap life of the internal thread can be improved, and vibration and noise generated when tapping is reduced. is there.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be embodied in other forms.

For example, in the above embodiment, the tap 10 in which the straight groove 18 is provided in the screw portion 14 has been described. The present invention can be similarly applied to various other taps having a shank consisting of

In the above-described embodiment, the portion corresponding to the straight portion 22 of the tap body has a small diameter, and the elastic member 26 is provided at the small diameter portion. However, the elastic member can be provided without providing such a small diameter portion. You may make it adhere to a tap main body with an adhesive agent etc.

Further, the holder 28 of the above embodiment is merely an example, and other holders provided with a rotation drive unit which engages with the engagement unit 24 so as to be relatively unrotatable with play and a holding unit which positions and holds the straight unit 22 are provided. Various holders can be used. For example, the rotation drive unit of the holder is
4 is substantially similar to the cross-sectional shape of FIG.
Can be abolished. Note that the cross-sectional shape of the engaging portion 24 does not necessarily have to be a square shape.

Although not specifically exemplified, the present invention can be embodied in various modified and improved forms based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of a straight shank tap according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a state in which the tap of FIG. 1 is held by a holder.

[Explanation of symbols]

10: Straight shank tap 12: Shank 14: Screw part 22: Straight part 24: Engagement part 26: Elastic member 28: Holder

Claims (1)

(57) [Scope of request for utility model registration] 1. A shank provided with a non-circular engaging portion at an end of a straight portion having a cylindrical shape, and a screw portion provided with a male screw having a shape corresponding to a female screw to be formed, In a state where the straight portion is positioned and gripped by the holder, a rotational force is applied from the holder via the engaging portion, whereby the straight portion is driven to rotate around the axis and is lead-fed relative to the workpiece. Accordingly, the straight shank taps to process the internal thread in a prepared hole provided in the workpiece by said threaded portion, the elastically deformable elastic member to the outer peripheral portion of the straight portion
In addition to the above, the engaging portion has a tap formed along with the elastic deformation of the elastic member.
To allow relative displacement with respect to the holder
The relative rotation of the holder with slight play
A straight shank tap characterized in that it can be locked so that it cannot roll .