CN2127645Y

CN2127645Y - Thread tap

Info

Publication number: CN2127645Y
Application number: CN 92226811
Authority: CN
Inventors: 廖来全; 班仕珍
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-07-02
Filing date: 1992-07-02
Publication date: 1993-03-03
Anticipated expiration: 2002-07-02

Abstract

The utility model relates to a thread tap. The utility model is characterized in that four edge lobes arranged in the sequent of a b c d and four corresponding chip flutes are circumferentially arranged at intervals on the cross section of a thread rod, a series of deviating tooth type screw threads with consistent deviation is arranged on the axial section of the edge lobes of a cutting tap, both sides of each screw thread and the half of each screw thread angle are in asymmetry, the deviations of the screw threads arranged on the an edge lobe and the c edge lobe are identical, the deviations of the screw threads arranged on the b edge lobe and the d edge lobe are identical, and the deviations of the screw threads arranged on the an edge lobe and the c edge lobe are opposite to the deviations of the screw threads arranged on the b edge lobe and the d edge lobe. The utility model has the advantages of alternative cutting operating mode, small friction resistance, high efficiency and long service life. The thread tap can be used for processing inner threads of work pieces made of any material, and the thread tap is suitable for mechanical processing in various fields.

Description

Thread tap

The utility model belongs to screw thread cutting instrument, particularly a kind of novel thread tap.

The thread tap that uses in the known industrial production, the cross section of screw mandrel has the sword lobe of four symmetries and the chip pocket of four symmetries usually, and sword lobe and chip pocket were arranged by the circle spacing; Its longitudinal section is a series of threads, and form of thread is the half-angle symmetric form.The defective of this screw tap is: (1) is because tooth form matches consistent with the tooth form of workpiece, when the screw tap spiral was shot the workpiece screw, three faces of the left and right sides of crest, tooth were all stressed, and under the situation of crest broad, frictional force, torsion are all very big, and screw tap easily fractures.(2) because the tooth form structure of tooth form and workpiece internal thread is identical and match, when the tooth cutting workpiece, cooling fluid can not flow into workpiece and tooth binding site in the smear metal layer, poor cooling performance, crest and surface of the work are easy to generate the friction high-temperature region, and when temperature rise is higher than the red hardness limiting temperature of screw tap material, " annealing " will appear in the tooth sword, aggravated the tooth sharpening and decreased, shorten dramatically service life.(3) crest participation cutting is incision successively, when the workpiece material toughness big (for example stainless steel) of cutting, be easy to take place surface largeization layer, cause crest wearing and tearing aggravation, make the passivation of tooth sword, increase cutting resistance, crest is difficult to cut surface of the work, light then workpiece that process is defective, can't finish the processing tasks of workpiece when serious.(4) chip removal is not good.Its main cause is that the crest width (is generally 0.3707P greatly, P is the pitch of standard trapezoidal thread), thereby the width that cuts out smear metal is also big, carry out continuously because of cutwork again, frangibility not after smear metal is cut out, be blocked in easily in the chip pocket, cause chip removal not smooth, be easy to the screw tap that fractures.

The purpose of this utility model provides a kind of novel thread tap, and it can carry out internal thread machining to the workpiece of ordinary metallic material, high-ductility alloy material and other special material.

In order to achieve the above object, the utility model is taked following technical solution: the screw mandrel cross-sectional structure of this thread tap is designed to four sword lobes by a, b, c, d order, and four corresponding chip pockets are arranged, and sword lobe and chip pocket were arranged by the circle spacing.Axial cross section edge on the cutting cone sword lobe is the consistent slanting teeth type threads of a series of deflections, tooth both sides, half of thread angle are asymmetry, wherein the deflection of the thread on the ac sword lobe is identical, and the thread deflection on the bd sword lobe is identical, and ac is partial to opposite with the thread on the bd sword lobe.Cutwork is carried out at twice, the left side of ac sword lobe cutting workpiece screw thread, the right-hand part of bd sword lobe cutting workpiece screw thread, a, b, c, d hocket, thereby the contact area of thread and workpiece is reduced, cutting force, frictional force reduce, the purpose that reach lightly durable, can carry out internal thread machining to the workpiece of various different materials.

The utility model has the advantages that: (1) has only two faces contacts alternately cutting at twice by every tooth that three contacts of every tooth of the trapezoidal thread of standard type cutting at one time changes the slanting teeth type thread into, the contact area decreased average of thread and workpiece half, cutting force and frictional resistance are greatly reduced, improved machining condition, tooth side is difficult for pulling, cut brisk laborsavingly, operating efficiency improves; (2) alternately cutting at twice because thread has only two faces to contact with workpiece, has the space of a face, and cooling fluid can fully be soaked into cutting region, is difficult for producing friction high temperature, and the tooth sword can not burnt " annealing ", can prolong the service life of screw tap; (3) alternately cutting at twice, the width of smear metal only have a chip width of the trapezoidal thread of original standard 1/2 or narrower, equivalent chip pocket strengthens, and makes chip removal smooth and easy, can not stop up, screw tap is frangibility not; (4) eliminated friction high temperature, tooth sword can not burn " annealing ", so just there is not surperficial hardening phenomenon in the workpiece material big to toughness yet, thereby can carry out internal thread machining to the special material of using on stainless steel material, Langaloy material and the aerospace industry.

Fig. 1 is a contour structures diagrammatic sketch of the present utility model.

Fig. 2 is its viewgraph of cross-section.

Fig. 3 is the axial cross section tooth form structure comparison diagram on the cutting cone of tangents sword lobe.

Fig. 4 is a screw tap tooth cutting workpiece view.

Below in conjunction with accompanying drawing the utility model is described in further detail.

In Fig. 1, the 1st, screw mandrel, available alloy tool steel or high-speed tool steel material are made, and hardness is HRC62-66, the 2nd, chip pocket can be a helicla flute, can be straight trough also, and shown in the figure is helicla flute, the 3rd, guide head, the 4th, cutting cone, the 5th, proofread and correct tooth, the 6th, square toes.

Fig. 2 is its viewgraph of cross-section.As seen from the figure, a, b, four sword lobes of c, d and corresponding chip pocket 2 are arranged on the cross section of screw tap, sword lobe, chip pocket become antithesis to arrange by the circle spacing.Certainly, the number of sword lobe and chip pocket can be four, six, eight even more, but should be even number.

Fig. 3 is the axial cross section tooth form structure comparison diagram on the cutting cone sword lobe.Fig. 3 A is the trapezoidal tooth form structure of standard of the prior art, the 7th, and crest, the 8th, tooth side, the 9th, alveolus, as seen from the figure, tooth is trapezoidal, alveolus also is trapezoidal, is symmetry.During cutting,

crest

7,8 three faces of two tooth sides all participate in cutting and contact with workpiece.Fig. 3 B is the tooth form structure on the utility model a, the c sword lobe, Fig. 3 c is the tooth form structure on the utility model b, the d sword lobe, as seen from the figure, on same screw tap, the thread form half-angle of tooth both sides, alveolus is asymmetry, and a is partial to consistent with the thread on the c sword lobe, b is partial to consistent with the thread on the d sword lobe, can be to be partial to left simultaneously, also can be to be partial to right-handly simultaneously, but the deflection of the thread on the thread on a c sword lobe and the b d sword lobe must be opposite.The purpose that is designed to this structure is to be convenient to the workpiece screw thread is divided hemisection to cut, reduce contact-making surface, reduces cutting resistance, makes cooling fluid can fully flow to cutting region, prevent the high temperature that rubs.

Fig. 4 is a screw tap tooth cutting workpiece view.S is the section of smear metal layer among the figure, and solid line 10 is the teeth on a sword lobe, and dotted line 11 is the teeth on the b sword lobe.Cutwork makes two bites at a cherry, and the sectional area of establishing smear metal is S, if a sword lobe is last tooth incision, cuts out bits and is S ₂, smear metal S then ₁By next tooth b sword lobe cutting, then be c sword lobe, the incision of d sword lobe, a, b, c, d cut in turn.

Claims

1, a kind of novel thread tap, comprise screw mandrel, it is characterized in that: this screw mandrel cross section has four at least by a, b, the tactic sword lobe of c, d and corresponding chip pocket, sword lobe and chip pocket were arranged by the circle spacing, axial cross section edge on the cutting cone sword lobe is the consistent slanting teeth type threads of a series of deflections, the half of thread angle of tooth both sides, alveolus is asymmetric, wherein the deflection of the thread on the ac sword lobe is identical, thread deflection on the bd sword lobe is identical, and ac is partial to opposite with the thread on the bd sword lobe.