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EP-4739452-A1 - MILLING HEAD WITH THROUGH HOLE HAVING CENTERING AND DRIVE SURFACES AT TOOTH-RECEIVING LOBES, TOOL HOLDER AND ROTARY MILLING TOOL

EP4739452A1EP 4739452 A1EP4739452 A1EP 4739452A1EP-4739452-A1

Abstract

A rotary milling tool has a tool holder and a milling head releasably attached thereto. The milling head has a head through recess opening out to the head forward and rearward surfaces. The recess includes a plurality of radially extending tooth-receiving lobes. The tool holder has a projection which includes a plurality of radially extending teeth. When assembled the teeth are located in the tooth-receiving lobes and provide centering and torque transfer capabilities.

Inventors

  • ZETTLER, MARTIN ULRICH

Assignees

  • ISCAR Ltd.

Dates

Publication Date
20260513
Application Date
20240610

Claims (20)

  1. 1. A milling head (24) having a head central axis (B) that defines opposite forward and rearward directions (DF, DR) and about which the milling head (24) is rotatable in a rotational direction (R), the milling head (24) comprising: opposing head forward and rearward surfaces (26, 28) and a head peripheral surface (30) extending therebetween, the head peripheral surface (30) extending circumferentially about the head central axis (B); a plurality of angularly spaced apart peripherally disposed cutting portions (40); and a head through recess (44) extending along the head central axis (B) and opening out to the head forward and rearward surfaces (26,28), the head through recess (44) being delimited circumferentially by a recess peripheral surface (46) and comprising a plurality of angularly spaced apart tooth-receiving lobes (48) extending radially outwardly; wherein: the recess peripheral surface (46) comprises a plurality of driven surfaces (58) and a plurality of radial centering surfaces (62), all being located at the plurality of toothreceiving lobes (48) and configured to abut corresponding surfaces on a tool holder (22), each driven surface (58) facing opposite the rotational direction (R) and each radial centering surface (62) facing radially inwardly; and the plurality of radial centering surfaces (62) are located radially outwards from the plurality of driven surfaces (58).
  2. 2. The milling head (24), according to claim 1, wherein: the recess peripheral surface (46) is oriented parallel to the head central axis (B).
  3. 3. The milling head (24), according to claims 1 or 2, wherein: the radial centering surface (62) subtends a centering surface angle (a) at the head central axis (B); and the centering surface angle (a) fulfils the condition: 20° < α < 40°.
  4. 4. The milling head (24), according to any one of claims 1-3, wherein: the head through recess (44) comprises a plurality of angularly spaced apart radial recess narrowings (50), circumferentially alternating with the tooth-receiving lobes (48) along the recess peripheral surface (46); and the recess peripheral surface (46) comprises a plurality of recess clearance surfaces (66), each recess clearance surface (66) being located at a respective radial recess narrowing (50) and facing radially inwardly.
  5. 5. The milling head (24), according to any one of claims 1-4, wherein: the plurality of radial centering surfaces (62) define an imaginary recess outermost cylinder (OC) centered at the head central axis (B).
  6. 6. The milling head (24), according to claim 5, wherein: the head through recess (44) comprises a plurality of angularly spaced apart radial recess narrowings (50), circumferentially alternating with the tooth-receiving lobes (48) along the recess peripheral surface (46); the recess peripheral surface (46) comprises a plurality of recess clearance surfaces (66), each recess clearance surface (66) being located at a respective radial recess narrowing (50) and facing radially inwardly; the plurality of recess clearance surfaces (66) define an imaginary recess innermost cylinder (IC) co-axial with the imaginary recess outermost cylinder (OC); the imaginary recess innermost cylinder (IC) has a recess innermost cylinder radius (IR); the imaginary recess outermost cylinder (OC) has a recess outermost cylinder radius (OR); and the recess innermost cylinder radius (IR) is less than or equal to 75% of the recess outermost cylinder radius (OR).
  7. 7. The milling head (24), according to claims 5 or 6, comprising: a plurality of angularly spaced apart fastening through holes (67), opening out to the head forward and rearward surfaces (26,28) and spaced apart from the head through recess (44); wherein: each fastening through hole (67) is located between two angularly adjacent toothreceiving lobes (48) of the head through recess (44).
  8. 8. The milling head (24), according to claim 7, wherein: the plurality of fastening through holes (67) are located inside, or intersected by, the imaginary recess outermost cylinder (OC).
  9. 9. The milling head (24), according to claims 7 or 8, wherein: each fastening through hole (67) extends along a respective fastening through hole axis (F); and the fastening through hole axes (F) are located inside the imaginary recess outermost cylinder (OC).
  10. 10. The milling head (24), according to any one of claims 1-9, wherein: the recess peripheral surface (46) has a recess height (H), as measured in the axial direction; and the plurality of radial centering surfaces (62) and the plurality of driven surfaces (58) extend the full recess height (H).
  11. 11. The milling head (24), according to any one of claims 1-10, wherein: the head through recess (44) comprises exactly three tooth-receiving lobes (48).
  12. 12. The milling head (24), according to any one of claims 1-11, wherein: every tooth-receiving lobe (48) has exactly one driven surface (58) and exactly one radial centering surface (62) located thereat.
  13. 13. The milling head (24), according to any one of claims 1-12, wherein the head rearward surface (28) comprises at least one rearwardly facing planar axial bearing surface (64a, 64b) which extends along an entire angular extent thereof.
  14. 14. The milling head (24), according to any one of claims 1-13, wherein: each tooth-receiving lobe (48) comprises a lobe narrowing (LN) and a lobe widening (LW) located radially outward of the lobe narrowing (LN); the lobe widenings (LW) have a maximum first width (wl) and the lobe narrowings (LN) have a maximum second width (w2); and the maximum first width (wl) is greater than the maximum second width (w2).
  15. 15. The milling head (24), according to any one of claims 1-14, wherein: the head through recess (44) comprises a central region (51) connecting to the plurality of tooth-receiving lobes (48); the radial length of each tooth-receiving lobe (48) from the central region (51) exceeds the radial extent of the central region (51).
  16. 16. A tool holder (22), having a holder central axis (C) that defines opposite forward and rearward directions (DF, DR) and about which the tool holder (22) is rotatable in the rotational direction (R), the tool holder (22) comprising: a shank peripheral surface (72) which extends circumferentially about the holder central axis (C); a shank forward end surface (70) bounded by the shank peripheral surface (72) located at a forward end of the tool holder (22); and a shank projection (74) projecting from the shank forward end surface (70) along the holder central axis (C), the shank projection (74) being delimited circumferentially by a projection peripheral surface (76) and comprising a plurality of angularly spaced apart centering drive teeth (78) extending radially outwardly; wherein: the projection peripheral surface (76) comprises a plurality of driving surfaces (82) and a plurality of radial alignment surfaces (84), all being located at the plurality of centering drive teeth (78) and configured to abut corresponding surfaces on a milling head (24), each driving surface (82) facing the rotational direction (R) and each radial alignment surface (84) facing radially outwardly; and the plurality of radial alignment surfaces (84) are located radially outwards from the plurality of driving surfaces (82).
  17. 17. The tool holder (22), according to claim 16, wherein: the projection peripheral surface (76) is oriented parallel to the holder longitudinal axis (C).
  18. 18. The tool holder (22), according to claims 16 or 17, wherein: each radial alignment surface (84) subtends an alignment surface angle (0) at the holder longitudinal axis (C); and the alignment surface angle (0) fulfils the condition: 20° < 0 < 40°.
  19. 19. The tool holder (22), according to any one of claims 16-18, wherein: the shank projection (74) comprises a plurality of angularly spaced apart radial projection narrowings (80), circumferentially alternating with the centering drive teeth (78) along the projection peripheral surface (76); and the projection peripheral surface (76) comprises a plurality of projection clearance surfaces (86), each projection clearance surface (86) being located at a respective radial projection narrowing (80) and facing radially outwardly.
  20. 20. The tool holder (22), according to any one of claims 16-19, wherein: the radial alignment surfaces (84) define an imaginary projection outermost cylinder (OC’) centered at the holder central axis (C).

Description

MILLING HEAD WITH THROUGH HOLE HAVING CENTERING AND DRIVE SURFACES AT TOOTH-RECEIVING LOBES, TOOL HOLDER AND ROTARY MILLING TOOL FIELD OF THE INVENTION [0001] The subject matter of the present application relates to rotary milling tools having a milling head with a plurality of peripherally disposed cutting portions, and in particular to such a milling head having a through hole. The through hole has a plurality of driven surfaces for torque transfer from a tool holder and a plurality of radial centering surfaces for radial alignment of the milling head with said tool holder. BACKGROUND OF THE INVENTION [0002] Rotary milling tools can include a milling head releasably clamped to a tool holder by at least one fastening member, e.g., a retaining screw. The milling head can have a plurality of peripherally disposed cutting portions. The milling head can have a through hole for engaging with a projection for providing radial centering of the milling head with respect to the too] holder. Typically, the through hole is cylindrical. The milling head can have a key way extending radially outwardly from the through hole for receiving a key which provides torque transfer from the tool holder to the milling head. [0003] A variety of such cutting tools and milling heads are disclosed in JP2021094680 A, DE202017105606 U1 and US 7,153,068. [0004] It is an object of the subject matter of the present application to provide an improved and compact engagement between a milling head a tool holder. SUMMARY OF THE INVENTION [0005] In accordance with a first aspect of the subject matter of the present application there is provided a milling head having a head central axis that defines opposite forward and rearward directions and about which the milling head is rotatable in a rotational direction (R), the milling head comprising: opposing head forward and rearward surfaces and a head peripheral surface extending therebetween, the head peripheral surface extending circumferentially about the head central axis; a plurality of angularly spaced apart peripherally disposed cutting portions; and a head through recess extending along the head central axis and opening out to the head forward and rearward surfaces, the head through recess being delimited circumferentially by a recess peripheral surface and comprising a plurality of angularly spaced apart tooth-receiving lobes extending radially outwardly; wherein: the recess peripheral surface comprises a plurality of driven surfaces and a plurality of radial centering surfaces, all being located at the plurality of tooth-receiving lobes and configured to abut corresponding surfaces on a tool holder, each driven surface facing opposite the rotational direction and each radial centering surface facing radially inwardly; and the plurality of radial centering surfaces are located radially outwards from the plurality of driven surfaces. [0006] In accordance with a second aspect of the subject matter of the present application there is provided a tool holder, having a holder central axis that defines opposite forward and rearward directions and about which the tool holder is rotatable in the rotational direction, the tool holder comprising: a shank peripheral surface which extends circumferentially about the holder central axis; a shank forward end surface bounded by the shank peripheral surface located at a forward end of the tool holder; and a shank projection projecting from the shank forward end surface along the holder central axis, the shank projection being delimited circumferentially by a projection peripheral surface and comprising a plurality of angularly spaced apart centering drive teeth extending radially outwardly; wherein: the projection peripheral surface comprises a plurality of driving surfaces and a plurality of radial alignment surfaces, all being located at the plurality of centering drive teeth and configured to abut corresponding surfaces on a milling head, each driving surface facing the rotational direction and each radial alignment surface facing radially outwardly; and the plurality of radial alignment surfaces are located radially outwards from the plurality of driving surfaces. [0007] In accordance with a third aspect of the subject matter of the present application there is provided a rotary milling tool, comprising: a milling head of the type described above; and a tool holder of the type described above; wherein: the milling head is releasably attached to the tool holder; the shank projection is located in the head through recess; the plurality of radial centering surfaces directly abut the plurality of radial alignment surfaces of the coupling portion; and the plurality of driven surfaces directly abut the plurality of driving surfaces. [0008] It is understood that the above-said is a summary, and that features described hereinafter may be applicable in any combination to the subject matter of the present application, for example, any of the following fea