JPH0560728U - Straight shank tap - Google Patents

Abstract

(57) [Abstract] [Purpose] Improving the machining accuracy and tap life of the female screw by properly absorbing the misalignment between the tap and the pilot hole and the error in lead feed without using a complicated floating mechanism. . A soft elastic member 26 is provided on an outer peripheral portion of a straight portion 22 which is positioned and gripped by a holder, and when a load is applied to the tap 10 at the time of tapping, the tap 10 is held by the elastic deformation of the elastic member 26. With respect to the above, relative displacement can be performed within a predetermined range.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement of a straight shank tap that is used by being attached to a tapping machine or the like.

[0002]

[Prior Art]

 A straight shank tap having a shank in which a non-circular engagement portion is provided at the end of a cylindrical straight portion and a thread portion in which a male screw having a shape corresponding to the female screw to be formed is provided Widely used as a tool. Such a straight shank tap is generally used by being attached to a spindle such as a tapping machine via a holder.The holding method is to insert the shank into the mounting hole of the holder, It is usual that the joint portion is engaged with the rotary drive portion provided at the bottom of the mounting hole so as to be relatively non-rotatable with a little play, and the straight portion is positioned and gripped by the collet chuck. The tap is rotated around the axis by rotating the rotary drive unit together with the collet chuck, but the drive torque at the time of tapping is related to the rotary drive unit that is engaged relatively non-rotatably. Transmitted to the joint, the collet chuck positions the taps concentrically to prevent runout and slip out of the holder. Further, by thus rotating the tap and feeding the lead relatively to the workpiece, the internal thread is machined by the threaded portion in the prepared hole provided in the workpiece.

[0003]

[Problems to be solved by the device]

 By the way, in such a tap stand, misalignment between the prepared hole and the tap, runout of rotation, lead feed error relative to the tap rotation speed, and backlash when the tap is reversely rotated to pull out the tap from the female screw after tap stand. Synchronous shift between reverse rotation start and reverse feed start cannot be avoided, but the tap is positioned and held by the holder in a fixed position.Therefore, due to the above-mentioned misalignment and feed error, etc. There was a problem that the accuracy decreased and the tool life was shortened due to excessive force applied to the tap. On the other hand, there is a tapping machine in which the tap axis is made to follow the axis of the pilot hole by the guide action of the tap itself, and the tap is screwed into the pilot hole according to the lead of the tap. In this case, a complicated mechanism that allows the holder holding the taps to be fixed in position in the radial direction and the axial direction of the tap axis is required, which makes the device large and expensive. was there.

The present invention has been made in view of the above circumstances, and its purpose is to satisfactorily absorb misalignment between the tap and the prepared hole, a feed error, etc. without using a complicated mechanism. In this way, it is to improve the processing accuracy of the internal thread and the tap life.

[0005]

[Means for Solving the Problems]

 In order to achieve such an object, the present invention provides a shank having a non-circular engaging portion at the end of a straight portion having a cylindrical shape and a screw having a male screw having a shape corresponding to a female screw to be formed. The straight portion is rotationally driven about the axis by applying a rotational force through the engaging portion in a state where the straight portion is positioned and gripped, and the lead is relatively moved with respect to the workpiece. In a straight shank tap in which a female screw is machined by the threaded portion in a prepared hole provided in the workpiece by being fed, a soft elastic member is provided on the outer peripheral portion of the straight portion. It

[0006]

[Action]

 In such a straight shank tap, since a soft elastic member is provided on the outer peripheral portion of the straight portion that is positioned and held by the holder, if a load is applied to the tap during tapping, the elastic member Due to the elastic deformation, the tap can be displaced relative to the holder within a predetermined range, and the misalignment between the tap and the pilot hole, the feed error, etc. are well absorbed. Specifically, with respect to misalignment and inclination of the prepared hole and tap, and runout of rotation, the tap is displaced in the direction perpendicular to the axis, so that misalignment and inclination are alleviated. With respect to the error in lead feed due to rotation and the deviation in synchronization, the feed error is mitigated by displacing the tap in the axial direction. As a result, a high precision female with less pile thinness can be machined, and the tool life is extended by reducing chipping and breakage of the tap. Further, the elastic deformation of the elastic member has an advantage that vibration, noise, and the like generated at the time of tapping can be reduced. In addition, since the engaging part provided at the end of the straight part is engaged with the rotary drive part in a relatively non-rotatable manner with a slight play, the relative displacement of the tap with respect to the holder is allowed and Even if is relatively displaced with respect to the holder, the rotational force is reliably transmitted through the engaging portion.

[0007]

[Effect of the device]

 In this way, according to the straight shank tap of the present invention, the misalignment between the tap and the pilot hole, the feed error, etc. are well absorbed by the elastic member, so that the holder that grips the tap moves in the radial direction of the tap axis. In addition, it is possible to improve the machining accuracy of the internal thread and the tap life without using a complicated mechanism that allows free movement in the axial direction, and at the same time reduce the vibration and noise that occur when tapping.

[0008]

【Example】

 An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a front view of a straight shank tap 10 (hereinafter, simply referred to as tap 10) according to an embodiment of the present invention as viewed from a direction perpendicular to an axis. The tap 10 includes a shank 12 and a threaded portion 14. The threaded portion 14 is provided with a thread-shaped male screw 16 corresponding to a female screw to be formed, and is parallel to the shaft center. A straight groove 18 of a book is provided and the male screw 16 is divided to form a cutting edge 20. The shank 12 includes a straight portion 22 having a columnar cross section and an engaging portion 24 integrally provided at an end of the straight portion 22 having a substantially square cross section. A soft elastic member 26 is provided on the portion. The tap body is made of high-speed tool steel or cemented carbide, and the portion corresponding to the straight portion 22 of the tap body has a slightly smaller diameter, and the elastic member 26 has a diameter of 0 mm. It 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 or synthetic rubber such as polyurethane resin or neoprene rubber, and the elastic member 26 formed in a cylindrical shape in advance is fitted to the tap body, It is provided on the tap body in a non-separable manner by bonding with an adhesive or by coating 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 fixed to the holder body 30 and a collet chuck 34 arranged on the driving piece 32. The drive piece 32 is formed with an accommodation hole 36 for accommodating the engaging portion 24 in its axial center, and a screw hole is provided so as to be orthogonal to the accommodation hole 36 so that a pair of set screws 38 are formed. It is screwed to face each other. The screwing amounts of the pair of setscrews 38 are adjusted in advance so that the dimension between the tips thereof is slightly larger than the width dimension of the engaging portion 24, and the driving piece 32 is opposed to the engaging portion 24. Are engaged with each other so that they cannot rotate relative to each other with a slight play. The collet chuck 34 includes a cylindrical member 40 having a tapered hole fixedly mounted on the driving piece 32, and a collet 42 having an outer peripheral surface having a tapered shape and fitted in the tapered hole of the cylindrical member 40. The cap member 44 is configured to push the collet 42 into the tapered hole by being screwed into the cylindrical member 40. The collet 42 is formed with a plurality of slits in the axial direction so that the collet 42 can be reduced in diameter. The straight portion 22 of the inserted tap 10 is positioned and grasped concentrically.

FIG. 2 shows the tap 10 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 accommodation hole 36. When the holder 28 is driven to rotate together with the main shaft, the tap 10 is also driven to rotate about its axis, and in that state, the lead is relatively fed to the work to be mounted on the work. A female screw is cut into the prepared pilot hole by the thread portion 14. The driving torque at the time of tapping is transmitted through the engaging portion 24 which is engaged with the pair of setscrews 38 of the driving piece 32 so as not to rotate relative to each other. Are positioned concentrically, and the tap 10 is prevented from coming out of the holder 28.

Here, in the tapping, in order to pull out the tap 10 from the female screw after the tapping, the misalignment between the prepared hole and the tap 10 and the fluctuation of the rotation, the error in the lead feed with respect to the rotation speed of the tap 10 Although a synchronism difference between the start of reverse rotation and the start of reverse feed due to backlash during reverse rotation is unavoidable, the tap 10 of the present embodiment has an outer periphery of the straight portion 22 that is positioned and gripped by the holder 28. A soft elastic member 26 is provided in the portion, and the elastic deformation of the elastic member 26 allows the tap 10 to be displaced relative to the holder 28 within a predetermined range. Misalignment and feed error are well absorbed. For example, with respect to the misalignment and inclination of the prepared hole and the tap 10, and the deflection of rotation, the misalignment and inclination of the tap 10 are alleviated by displacing the tap 10 in the direction perpendicular to the axis. With respect to the lead feed error and the synchronization deviation with respect to the above, the feed error and the like are alleviated by displacing the tap 10 in the axial direction. As a result, a high-precision female screw with a small amount of thread thinning can be processed, and the tool life of the tap 10 can be extended by reducing chipping and breakage of the tap 10. Further, the elastic deformation of the elastic member 26 has an advantage that vibration, noise and the like generated at the time of tapping are reduced.

The engaging portion 24 provided at the end of the straight portion 22 is engaged with the set screw 38 with a slight play so as not to be able to rotate relative to the engaging portion 24. Since the holder 28 is held with a gap between the holder 28 and the bottom of the accommodation hole 36, the relative displacement of the tap 10 with respect to the holder 28 is impaired by the engagement between the engaging portion 24 and the driving piece 32. In addition, even if the tap 10 is displaced relative to the holder 28, the rotational force is reliably transmitted via the engaging portion 24.

As described above, according to the tap 10 of the present embodiment, the misalignment with the prepared hole, the feed error, and the like are favorably absorbed by the elastic member 26, so that the holder 28 that holds the tap 10 has the tap axis center. It is possible to improve the machining accuracy of the internal thread and the tap life without using a complicated mechanism that allows it to move freely in the radial and axial directions, and reduce the vibration and noise that occur when tapping. Is done.

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

For example, although the tap 10 in which the straight groove 18 is provided on the threaded portion 14 is described in the above embodiment, it is engaged with a straight portion such as a spiral tap, a spiral point tap, a build-up tap, a pipe tap, and a nut tap. The present invention can be similarly applied to various other taps provided with a shank consisting of parts.

Further, 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 in the small diameter portion. However, the elastic member is not provided with such a small diameter portion. It may be fixed to the tap body with an adhesive or the like.

Further, the holder 28 of the above-described embodiment is merely an example, and is provided with the engaging portion 24, the rotation driving portion which engages with the play portion in a relatively non-rotatable manner, and the grasping portion which positions and grasps the straight portion 22. Various other holders can be used. For example, the rotary drive portion of the holder may be substantially similar to the cross-sectional shape of the engaging portion 24, and the pair of setscrews 38 may be eliminated. The cross-sectional shape of the engaging portion 24 does not necessarily have to be a square shape.

Although not illustrated one by one, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of 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 cross-sectional view showing a state where the tap shown in 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

Claims (1)

[Scope of utility model registration request] 1. A shank having a non-circular engagement portion provided 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, When the straight portion is positioned and gripped, it is rotationally driven around the axis by applying a rotational force through the engaging portion, and the lead is relatively fed to the workpiece, so that the workpiece is processed. What is claimed is: 1. A straight shank tap, wherein a female screw is machined by the threaded portion in a prepared hole provided in an object, wherein a soft elastic member is provided on an outer peripheral portion of the straight portion.