Thread forming tool

Abstract

The invention relates to a thread forming tool having a thread part based on a helical effective surface (1), and an adjoining clamping shank (2), wherein the helical effective surface (1) is formed by pressing lobes (5) and the thread part extends from a chamfer or taper (6) in the direction of the clamping shank (2). Furthermore, at least one axially oriented, groove-like cooling channel (7) that runs between the pressing lobes (5) and extends from the chamfer or taper (6) to the clamping shank (2) is provided. According to the invention, the width of the at least one cooling channel (7) increases from the chamfer (6) in the direction of the clamping shank (2).

Claims

1. A thread forming tool comprising: a thread part on a helical effective surface; an adjoining clamping shank, wherein the helical effective surface is formed by pressing lobes and the thread part extends from a chamfer located at a tip of the thread forming tool in an axial direction of the thread forming tool toward the clamping shank, as well as having at least one axially oriented cooling channel that runs between the pressing lobes and extends from the chamfer toward the clamping shank, wherein the at least one cooling channel comprises a groove configured to receive and guide a coolant along the at least one cooling channel; and wherein a width of the at least one cooling channel continuously increases between the pressing lobes in the axial direction from the chamfer toward the clamping shank.

2. The thread forming tool of claim 1, wherein an end of the at least one cooling channel pointing to the clamping shank passes into a conically fanned-out area.

3. The thread forming tool of claim 2, wherein the cooling channel has a depth that decreases in the portion of the conically fanned-out area.

4. The thread forming tool of claim 1, wherein the at least one cooling channel extends in the axial direction beyond the thread part up into a transition area toward the clamping shank.

5. The thread forming tool of claim 1, wherein, at least one radial bore opens into the at least one cooling channel, which radial bore passes into a central through-bore reaching up to an end of the clamping shank so as to ensure a coolant flow.

6. The thread forming tool of claim 5, wherein the at least one cooling channel starts at the radial bore.

7. The thread forming tool of claim 5, wherein the at least one radial bore has a course that deviates from a direction perpendicular to the axial direction of the thread forming tool.

8. The thread forming tool of claim 1, wherein the pressing lobes are formed, with the cooling channel extending between two adjacent pressing lobes.

9. The thread forming tool according to claim 8, wherein there are a number of pressing lobes and the number is in the range between 2 and 10.

10. A method of using a thread forming tool according to claim 1 for a thread forming process using a reduced amount of lubrication.

Description

(1) The invention will be explained in more detail below by means of an exemplary embodiment and referring to the figures.

(2) Shown are in:

(3) FIG. 1 a longitudinal view, not to scale, of the thread forming tool according to the invention, having a central coolant bore, as well as a detailed representation of the thread part and the visible increase in the cross-sectional area, in particular the width of an outer surface coolant groove;

(4) FIG. 2 a longitudinal section view of a portion of the thread part of the thread forming tool having an obliquely extending radial bore passing into the central cooling channel, and

(5) FIG. 3 a side view of a further embodiment of the thread forming tool having a cooling channel that increases in its cross-sectional area, in particular in its width, along with a detailed representation of the conically fanned-out areas of the cooling channel(s).

(6) In the representation according to FIG. 1 a longitudinal side view of a thread forming tool according to the invention as well as a front side view with a view to the thread part are illustrated in the upper part of the figure.

(7) The thread forming tool accordingly exhibits a helical effective surface 1 and has a clamping shank 2 with a tool holder 3, e.g. in the form of a polygon, in particular a square.

(8) The structure of the thread forming tool is essentially rod-shaped and has, between its tip in area A and its clamping end in area B, a diameter step formation 4 that virtually forms a transition area between the step part and the clamping shank 2.

(9) In the front view according to FIG. 1, i.e. the view of the front side of the thread forming tool, five pressing lobes 5 are visible.

(10) As shown in FIG. 1, thread part 1 extends from a chamfer or taper 6 in the direction of clamping shank 2, namely across a defined length portion.

(11) Cooling channels 7, which are visible as a detailed representation in the lower image part of FIG. 1, are located between the pressing lobes 5.

(12) According to one embodiment, the cooling channels 7 are widened in the direction of clamping shank 2, namely starting from an imaginary continuous straight line, for instance, 1 to 10 to the left and right.

(13) The thread part is profiled in its outer diameter, and the chamfer has the exemplary lead angle illustrated in the Figure.

(14) The surface area increase of the grooves 7 is continuous in the exemplary embodiment according to the Figures and, as shown in FIGS. 1 and 3, passes into an exemplary conically but also shell-like fanned-out area 8.

(15) In the portion of the conically fanned-out area 8, the depth of the cooling channel 7 may be realized to be decreasing.

(16) As can be understood from the representations, the formation of the cooling channels 7 extends in the axial direction beyond the thread part 1 up into the area toward the clamping shank across a defined length of the part of reduced diameter of the thread forming tool (see in each case the upper representations according to FIGS. 1 and 3).

(17) As can be understood from FIG. 2, which illustrates a longitudinal cut through the front portion of thread part 1, a central through-bore 10 is formed in the thread forming tool which is closed at its front end pointing toward taper 6 and passes into at least one radial bore 11. Through the central bore 10 together with the adjoined radial bore 11, coolant can be supplied and guided backward via the corresponding cooling channels 7.

(18) The radial bore 11 has a course deviating from the normal relative to the dash-dotted longitudinal axis of the tool, namely exhibits, as an example, an angle in the range of 30 to <90, e.g. 45 having an outflow direction toward taper 6.

(19) The number of cooling channels 7 according to the exemplary embodiment is five, and five pressing lobes 5 are formed. The groove width expands, as an example, in a range from about 1 mm to a fan area of about 3 mm.

(20) The surface of the thread forming tool is hardened and, where appropriate, coated at least in the area of the thread part.

(21) The formation of the cooling channels 7 may be performed by grinding in a manner known as such, with alternative fabrication methods being conceivable.