THREADING TOOLS WITH FLUID DUCTS

Abstract

The present invention relates to a threading tool for producing a thread notch on a workpiece. The production may be both material-removing production and also chipless production. The threading tool comprises at least two regions, a distal machining region with a machining head, and a proximal shank region with a shank, which shank narrows toward the machining region via a shoulder. Furthermore, the threading tool according to the invention is designed such that at least one fluid duct extends through the shank, which at least one fluid duct opens out in the machining region.

Claims

1: Threading tool for producing a thread notch on a workpiece, wherein the threading tool comprises at least two regions: a) a distal machining region with a machining head, and b) a proximal shank region with a shank, and wherein at least one fluid duct extends through the shank, which at least one fluid duct opens out in the machining region.

2: Threading tool according to claim 1, wherein the tool is a thread tap.

3: Threading tool according to claim 1, wherein the tool is a tool for the chipless production of a thread notch, in particular a thread former.

4: Threading tool according to claim 1, wherein the tool is a chip-removing tool for the production of a thread notch, in particular a thread milling cutter.

5: Threading tool according to claim 1, wherein the shank region is separated from the machining region by a shoulder, and wherein in particular, the shank narrows toward the machining head.

6: Threading tool according to claim 5, wherein, on the shoulder, there is provided at least one mouth at which the at least one fluid duct opens out in the machining region.

7: Threading tool according to claim 1, wherein the at least one fluid duct runs parallel to the central longitudinal axis.

8: Threading tool according to claim 1, wherein a multiplicity of fluid ducts is provided, which fluid ducts are arranged radially around, and parallel to, a central longitudinal axis of the tool.

9: Threading tool according to claim 8, wherein the fluid ducts are spaced apart by a certain angle, in particular such that the shank is configured substantially rotationally symmetrically about the central longitudinal axis of the tool.

10: Threading tool according to claim 1 wherein the shank is configured such that it can be clamped in a machine tool, wherein in particular, the shank has at least one clamping element or the shank is configured such that it can be clamped in a machine tool, wherein in particular, the shank has a square-section profile as a clamping element at the proximal end.

11: Threading tool, in particular according to claim 1, comprising a distal machining region with a machining head and comprising a proximal shank region with a shank, wherein the machining region has a multiplicity of cutting elements which are arranged radially about a central longitudinal axis of the tool, and wherein the cutting elements span a certain angle relative to one another, and wherein at least two angles spanned in this way are of different magnitude.

12: Threading tool, in particular according to claim 1, comprising a distal machining region with a machining head, and comprising a proximal shank region with a shank, wherein the machining region has multiple recesses which are arranged around the machining head and which extend in spiral fashion in the longitudinal direction of the tool about the longitudinal axis, and a first recess has a different helix angle than a second recess.

13: Threading tool, in particular according to claim 1, comprising a distal machining region with a machining head and comprising a proximal shank region with a shank, wherein the machining region has recesses which are arranged around the machining head, in particular has at least one curling chamfer, of which at least one is designed so as to transition from a spiral-shaped recess via a curve into a straight recess.

Description

[0072] In the figures, for a simplified illustration, analogous elements will be denoted in each case by the same reference designations. In the figures, in each case schematically:

[0073] FIG. 1 shows a thread tap according to the invention;

[0074] FIG. 1a shows the thread tap of FIG. 1 in profile, with a partial profile cross section;

[0075] FIG. 1b shows the thread tap of FIG. 1 in a front view;

[0076] FIG. 2 shows a thread milling cutter according to the invention;

[0077] FIG. 2a shows the thread milling cutter according to the invention of FIG. 2 in a profile view with a partial cross section;

[0078] FIG. 2b shows a front view of the thread milling cutter from FIG. 2;

[0079] FIG. 3 shows a thread former according to the invention;

[0080] FIG. 3a shows the thread former of FIG. 3 in profile with a partial cross section;

[0081] FIG. 3b shows the thread former of FIG. 3 in a front view;

[0082] FIG. 4 shows a cross section through a thread tap with radially asymmetrically arranged cutting elements;

[0083] FIG. 5 shows a side view of a thread tap with variable helix angles;

[0084] FIG. 6 shows a side view of a thread tap with a transition from a spiral-shaped curling chamfer to a straight curling chamfer.

[0085] FIG. 1 shows, by way of example, a thread tap which is suitable for realizing the teaching according to the invention. The thread tap 1 can, broadly speaking, be divided into a machining region A and a shank region B. The machining region A comprises a machining head 1.2 which, at the distal end, has cutting elements 1.3. Overall, the thread tap 1 has three cutting elements 1.3 which are formed in each case from a row of cutting teeth arranged one behind the other. The cutting elements 1.3 of the thread tap 1 are spaced apart from one another in each case by an angle of 120, and substantially form a triangle with respect to the central longitudinal axis of the thread tap 1. At its distal end 1.4, the thread tap 1 tapers to a point, and in the present embodiment, is conical. Chip discharge grooves 1.5 are provided between the cutting elements 1.3. The chip discharge grooves 1.5 begin directly behind the distal end of the thread 1 and extend over the entire length of the cutting elements 1.3, over more than four fifths of the machining head 1.2. In the present example, the chip discharge groove 1.5 is rounded and describes a helix around the machining head in order to facilitate the discharge of the chips. In the present example, the arrangement is of positive spiral-shaped form. The chip discharge groove may however also facilitate the supply of fluids, and may have an additional function as a circulating lubrication means. For this purpose, it is particularly advantageously the case in the present embodiment that the mouth 1.7 of the fluid duct is arranged substantially coaxially with respect to the chip discharge groove 1.5. The mouth 1.7 is arranged at the distal end of the shank 1.8, more specifically on a tapering shoulder 1.9 of the shank, whereby said mouth opens out in the machining head 1.2. In the present example, the number of fluid ducts (not shown) corresponds to the number of mouths 1.7, and said number in turn corresponds to the number of cutting elements 1.3 and corresponding chip discharge grooves 1.5.

[0086] At the proximal end of the shank 1.8 and of the thread tap 1, there is formed a clamping element 1.10 for clamping, with the action of an operative connection, in a machine tool. The clamping element 1.10 is, in the present example, in the form of a square-section profile, and, together with the shank, ensures said operative connection.

[0087] The tool shown by way of example is composed of a high-speed steel.

[0088] The arrangement of the fluid ducts makes it possible for a coolant or a lubricant to be conducted directly into the machining region. An additional positive effect is the additional internal cooling that is made possible by way of the fluid ducts in the tool.

[0089] FIG. 1 shows the thread tap schematically in a perspective view. The fluid ducts can be seen more clearly in FIG. 1a, which shows the thread tap 1 from FIG. 1 in profile with a partial cross section through a fluid duct 1.11. The fluid duct 1.11 extends substantially over the entire length of the shank 1.8. It has a mouth 1.7 at its distal end and correspondingly has an inlet 1.12 at its proximal end. The terms mouth and inlet are not chosen here so as to represent a limitation in terms of functionality. In most cases, a fluid is introduced through the inlet 1.12 into the fluid duct 1.11, which fluid then passes into the machining region at the mouth 1.7. It is however likewise conceivable for a suction effect to be used, and thus for the mode of operation of the individual elements of mouth 1.7 and inlet 1.12 to be reversed.

[0090] In the present example, the mouths 1.7 are formed on the shoulder 1.9, such that a fluid emerges substantially axially from the mouth after having been conducted in a fluid jet which is substantially parallel to the longitudinal axis of the tool.

[0091] FIG. 1b shows the thread tap 1 from FIG. 1 in a front view. It is possible to particularly clearly see the substantially triangular arrangement of the fluid mouths 1.7, 1.7, 1.7. Likewise clearly visible from said figure is the cross section of the fluid ducts. In this case, the fluid ducts are arranged so as to be oriented in substantially half-moon-shaped fashion relative to the central longitudinal axis. By way of this arrangement, it is possible to realize an ideal fluid curtain during the rotation of the thread tap, which ensures an optimum supply of a lubricant to the machining area.

[0092] The thread tap that is shown is designed so as to be suitable for producing conventional thread forms. In the present example, said thread tap has for example 9 rows of teeth, though may have between one and 25 rows of teeth, entirely in accordance with the ideas of a person skilled in the art and the required guidance of the thread tap. The illustration shows a thread tap for producing a single-flight thread. Embodiments for producing multi-flight threads can be derived from this by a person skilled in the art.

[0093] Likewise, the cutting edge geometry is of secondary importance for the embodiment of the threading tool according to the invention. A person skilled in the art will select the corresponding cutting edge geometry, such as lip width, draft angle, rake angle and chamfer angle in accordance with the result to be achieved.

[0094] The recesses which sometimes, by way of their shape, define the cutting elements are, in the version shown, spaced apart from one another symmetrically by 120. It is however also conceivable for the recesses to be spaced apart asymmetrically, in the case of a thread tap with three cutting elements of for example 130, 110 and 120. In the present example, all three recesses have the same helix angle (not shown). Furthermore, in the embodiment shown, both the core radius and the helix angle are constant along the tool axis.

[0095] FIG. 2 shows a thread milling cutter 2 according to the invention. Said thread milling cutter can also be divided into a shank region B and a machining region A. The entire shank region B is formed by the shank 2.8, which tapers via a shoulder 2.9 into a machining head. The machining head has, in the present case, three cutting elements 2.3 and chip discharge grooves 2.5 which are spaced apart by in each case three cutting elements 2.3, which chip discharge grooves in turn form a lubricating groove 2.5. By contrast to thread taps (FIG. 1), the thread milling cutter 2 is formed with a flat distal end 2.4. The mouths 2.7 of the fluid ducts are arranged on the shoulder 2.9.

[0096] Analogously, FIG. 2a shows the thread milling cutter 2 in profile with a partial cross section. In this case, too, the fluid duct 2.11 extends through the entire length of the shank 2.8, and an inlet 2.12 permits the supply of a fluid through the fluid duct 2.11, which runs parallel to the central longitudinal axis, to the mouth 2.7 in the machining region, and also again substantially coaxially with respect to the chip discharge grooves 2.5. The twist of the chip discharge grooves follows that of the cutting elements 2.3. The distal end 2.4 is flat.

[0097] FIG. 2b shows the front view as seen from the distal end, with the three mouths, and corresponding fluid ducts, arranged in triangular fashion with respect to one another.

[0098] FIG. 3 correspondingly shows a thread former according to the invention. Analogously to the preceding threading tools, the thread former also has a shank 3.8 which ends at the proximal end with a clamping element 3.10 for the operative connection to a machine tool; in the present example, the clamping element 3.10 is in the form of a square-section profile. The shank tapers toward the machining head 3.2 via a shoulder 3.9, on which a row of mouths 3.7, 3.7, 3.7, 3.7 are arranged radially around a central longitudinal axis. The present thread former 3 has a total of four fluid ducts and four mouths 3.7, 3.7, 3.7, 3.7. The mouths 3.7, 3.7, 3.7, 3.7 are arranged coaxially with respect to lubricating grooves 3.14, of which there are in turn a total of four and which extend from a proximal region of the machining head 3.2 as far as the very distal end 3.4 of the thread former 3. The thread former 3 that is shown has a total of four pressing lobes 3.15, 3.15 with lens-shaped polygonal teeth.

[0099] An advantage of thread forming in relation to thread milling and/or thread tapping is that no chips accumulate during the machining, which increases the process reliability overall. Also, thread formers for relatively large thread depths and thickened material structures can be realized by way of deformation. In the case of expensive materials, it is furthermore the case that there is no significant loss of material.

[0100] FIG. 3a then also shows the thread former in profile with a partial cross section, analogously to the corresponding figures relating to the thread tap and to the thread milling cutter. In this case, too, the fluid duct 3.11 extends over the entire length of the shank 3.8 to the mouth 3.7 proceeding from an inlet 3.12. The inlet 3.12 is formed directly adjacent to the clamping element, such that said inlet can be connected particularly expediently to a corresponding fluid supply. In this example, too, the clamping element is in the form of a square-section profile. The mouth 3.7 is again situated on a tapering shoulder, and in the present example, is formed coaxially with respect to a lubricating groove. In the present example, the lubricating groove 3.14 is formed coaxially with respect to the mouth 3.7. The lubricating grooves 3.14 space the pressing lobes 3.15 and 3.15 apart in each case. The distal end 3.4 is, as a centring tip, designed so as to be conical and so as to taper to a point.

[0101] FIG. 3b illustrates the arrangement of the mouths 3.7, 3.7, 3.7 and 3.7 in a plan view from said distal end 3.4. Here, the mouths are in each case spaced apart from one another by an angle of 90, which ensures rotational symmetry of the tool about the central longitudinal axis.

[0102] In this embodiment, it is furthermore the case that the lubricating grooves and pressing lobes are spaced apart from one another in each case by an angle of 90, which ensures rotational symmetry of the tool about the central longitudinal axis. Analogously to the thread tap or the thread milling cutter, the pressing lobes or the cutting elements may be spaced apart from one another asymmetrically.

[0103] Numerous further advantageous embodiments emerge to a person skilled in the art from the examples shown and from the abovementioned general embodiments of the teaching according to the invention.

[0104] With the present invention, a threading tool is provided which permits a high throughput by way of simultaneous internal and external cooling and a supply of a fluid to a machining zone, which is precisely controllable and permits a good distribution of the fluid.

[0105] With the present invention, a threading tool is provided which has a relatively long service life. Without restriction to this theory, such an increase in service life may be made possible by way of the simultaneous internal and external cooling and the supply of a fluid to the machining zone. Said supply may be controlled in a precise manner, and in accordance with the required location, by way of the form of the cooling ducts.

[0106] Owing to the coolant and lubricant curtain produced at the required location by way of the present invention, it is possible in particular to prevent lubricant film separation at the contact zone in the machining region between threading tool and the material to be machined. A constant lubricating film prevents and considerably delays adhesive wear. Furthermore, by way of the coolant curtain at the required location, the cooling is improved, in particular in the case of the thread tap.

[0107] For the production of a compact coolant and lubricant curtain, it is advantageous to provide a defined coolant pressure, which is usually provided by way of a pump of the coolant treatment system.

[0108] The preferred defined coolant pressure amounts to at least 10 bar, in order that a significantly improved cooling and lubricating action is also realized. The optimum operating range of the present invention lies at a coolant pressure of 40 to 90 bar or, in the case of certain tool constructions, even higher.

[0109] FIG. 4 shows a threading tool according to the invention in profile cross section at the distal end. FIG. 4 serves for illustrating an aspect of the present invention in which the threading tool head has cutting elements which are spaced apart from one another differently, that is to say which are not oriented rotationally symmetrically about the central axis of rotation of the threading tool. The corresponding threading tool has three cutting elements 4.3, 4.3 and 4.3. Said cutting elements are designed differently and have in each case one cutting edge 4.21, 4.21, 4.21. Measured from cutting edge to cutting edge, the cutting elements span an angle 4.16, 4.16, 4.16. The threading tool that is shown by way of example spans a total of three such angles 4.16, 4.16, 4.16, which make up a total angle of 360. In the present example, a first angle 4.16 spans an angle of 143, a second angle 4.16 spans an angle of 101, and a third angle 4.16 spans an angle of 116.

[0110] FIG. 5 shows an aspect of the present invention in which a row of recesses 5.5, 5.5 have mutually different helix angles. The threading tool which is shown has a total of three cutting elements 5.3, 5.3 which are arranged radially around the central longitudinal axis. Between said cutting elements there are provided recesses, composed for example of chip discharge grooves, which likewise twist radially and helically around the central longitudinal axis of the threading tool. If said recesses have mutually different helix angles, this gives rise to the different spacings between the recesses 5.5, 5.5. In the present example, the cutting elements are thus formed with greater or lesser thickness (with respect to their extent in the longitudinal direction of the threading tool). A first thickness 5.20 in the longitudinal direction is greater than a second thickness 5.21 in the longitudinal direction.

[0111] FIG. 6 shows an aspect of the present invention in which a threading tool has a helix angle which describes a curve and decreases to zero. FIG. 6 shows a machining head with cutting elements 6.3, 6.3 which are interrupted by a recess which transitions from a spiral-shaped first recess 6.18, which starts at the distal end, via a transition zone 6.17 to a straight-running recess 6.13. Said straight-running recess runs parallel to the longitudinal axis of the threading tool.

[0112] The improved running smoothness of the threading tool owing to asymmetrically arranged cutting edges or different helix angles of the recesses and the transition-free curling chamfer increased the service life of the tool. Furthermore, it is also possible, for the chip discharge to be significantly influenced, and thus likewise for the service life of the threading tool to be improved, by way of increasing or decreasing core radius of the recess.