Milling tool

Patent metadata

Field	Value
Publication number	US-9579736-B2
Application number	US-201314018595-A
Country	US
Kind code	B2
Filing date	Sep 5, 2013
Priority date	Sep 7, 2012
Publication date	Feb 28, 2017
Grant date	Feb 28, 2017

Abstract

The invention relates to a milling tool for gear milling. The tool body is equipped with tangentially mounted milling inserts having four cutting edges and two holes, only one of which is utilized for a fixing screw in two of totally four index positions. By locating a screw hole in the seat of the milling insert at a distance from the radial support surface of the seat that is greater than the distance between an individual hole and a distal end of the milling insert, a clamping force is provided by means of the inherent elasticity of the fixing screw. In such a way, the milling insert is pressed against the radial support surface. By means of a transversal eccentricity, the milling insert is also pressed against a tangential support surface in the seat. By means of this construction, the two holes in differently long milling inserts can be formed with equally large distances from distal ends. Thereby, one and the same tool body can be equipped with differently long milling inserts.

First claim

The invention claimed is:

1. A milling tool comprising:
a basic body rotatable on a centre axis and including a peripheral cam having two flank surfaces converging toward a common transition surface, in each of the flank surfaces there is countersunk a plurality of tangentially spaced-apart seats, each of the plurality of seats including a radial support surface, a tangential support surface, and an axial support surface having a radially outer end and a single screw hole mouthing in the axial support surface, the single screw hole being radially spaced apart from the radial support surface by a first radial distance, the first radial distance being greater than a second radial distance between the radially outer end of the axial support surface and the single screw hole; and
a plurality of replaceable milling inserts, each of the plurality of inserts having an elongate basic shape and including two opposite and mutually parallel chip surfaces, two opposite and mutually parallel clearance surfaces and a pair of opposite ends, each of the two chip surfaces transforming into connecting clearance surfaces via a pair of alternately usable cutting edges having identical shape, each of the plurality of milling inserts being fixed in an appurtenant seat by a single screw that is tightened in the single screw hole, wherein the pair of opposite ends are a first end and a second end being separated by a first insert distance forming a total length of the milling insert, each of the plurality of milling inserts including two through holes, which extend continuously between the clearance surfaces, a first through hole being separated from the first end by a second insert distance and a second through hole being separated from the second end by the same second insert distance, the first through hole being separated from the second end by a third insert distance and the second through hole being separated from the first end by the same third insert distance, the third insert distance being greater than the first radial distance between the single screw hole and the radial support surface of the seat while providing a longitudinal eccentricity between the single screw hole and one of the first and second through holes in the respective milling insert, each of the first and second through holes being separated from a respective chip surface by a fourth insert distance that is greater than a transversal distance between the single screw hole and the tangential support surface while providing a transversal eccentricity between one of the first and second through holes and the single screw hole, the longitudinal and transversal eccentricities upon tightening of the single screw applying a clamping force to the milling insert, such that the clamping force resiliently presses the respective milling insert against the radial support surface and against the tangential support surface.

2. A milling tool according to claim 1 , wherein the longitudinal eccentricity is at least 0.10 mm.

3. A milling tool according to claim 1 , wherein the transversal eccentricity is at least 0.05 mm.

4. A milling tool according to claim 1 , wherein the first and second through holes are separated by a mutual distance, each of the milling inserts is included in a kit that includes differently long, equally wide milling inserts, a longer milling insert having the two through holes separated by a first mutual distance and a shorter milling insert having the two through holes separated by a second mutual distance, the first mutual distance being smaller than the second mutual distance, the third insert distance in the longer milling insert and the third insert distance in the shorter milling insert being equal.

5. A milling tool according to claim 4 , wherein the second insert distance between the first through hole and the first end of a respective longer or shorter individual milling insert is equal, wherein the second insert distance is smaller than the first and second mutual distance between the two through holes.

6. A milling tool according to claim 1 , wherein the two through holes of each individual milling insert have a countersink that receives a screw head, one of the countersinks opening in one of the clearance surfaces and the other one of the countersinks opening in the opposite clearance surface.

7. A milling tool according to claim 6 , wherein in each clearance surface of each milling insert, a first hole and a second hole mouth, the first hole having a countersink with a greater mouth in the clearance surface than the second hole.

8. A milling tool according to claim 6 , wherein at the chip surface of the milling insert, two diagonally opposite analogously shaped arched part edges are formed.

9. A milling tool according to claim 1 , wherein the opposite ends of each milling insert are mutually parallel.

10. A milling tool according to claim 1 , wherein the two through holes of each milling insert are shaped so that centre axes thereof are situated in a symmetry plane situated halfway between the chip surfaces of the respective milling insert.

11. A milling tool according to claim 8 , wherein at the proximal end of the milling insert, each of the arched part edges is primarily situated on the same side of a neutral plane as the countersink that is situated closest to the proximal end, the neutral plane being situated halfway between the two clearance surfaces.

12. An insert kit for milling tools comprising a plurality of milling inserts, each of the plurality of milling inserts having an elongate basic shape and two opposite and mutually parallel chip surfaces, two opposite and mutually parallel clearance surfaces, a pair of opposite ends and two through holes, the through holes extending continuously between the clearance surfaces, each clearance surface having a single countersink, each one of the two chip surfaces transforming into connecting clearance surfaces via a pair of alternately usable cutting edges having an identical shape, wherein the plurality of milling inserts form two sets of differently long, although equally wide milling inserts, a longer milling insert having the two through holes separated by a first mutual distance and a shorter milling insert having the two through holes separated by a second mutual distance, the first mutual distance being smaller than the second mutual distance, wherein the pair of opposite ends are a first end and a second end being separated by a first longer insert distance and a first shorter insert distance forming a total length of the longer and shorter milling insert respectively, a first through hole of the longer milling insert being separated from the first end of the longer milling insert by a second insert distance and the first through hole is separated from the second end of the longer milling insert by a third insert distance, wherein a first through hole of the shorter milling insert is separated from the first end of the shorter milling insert by a shorter second insert distance, which is a smaller distance than the second insert distance of the longer insert, and the first through hole is separated from the second end of the shorter milling insert by the same third distance as the longer milling insert.

13. An insert kit according to claim 12 , wherein the second distance between the first hole and the first end of the individual longer or shorter milling insert is equally large, but smaller than the first mutual and second mutual distance between the two through holes on the longer and shorter milling inserts respectively.

14. An insert kit according to claim 12 , wherein each of the two through holes of the individual milling inser

Assignees

• Sandvik Intellectual Property

Inventors

• Sjoo Sture

Classifications

• B23C5/2213

  having a special shape · CPC title

• B23C5/2204 Primary

  with cutting inserts clamped against the walls of the recess in the cutter body by a clamping member acting upon the wall of a hole in the insert · CPC title

• B23C5/2208

  for plate-like cutting inserts  (B23C5/2226, B23C5/2234 take precedence) · CPC title

• Y10T407/1725

  including holder having seat for inserted tool · CPC title

• B23F21/166 Primary

  in exchangeable arrangement · CPC title