MILLING TOOL AND COOLANT SLEEVE THEREFOR

Abstract

A milling tool having a shank portion and a head portion extending from the shank portion. A head internal surface of the head portion is formed with a peripherally extending head coolant obstruction arrangement comprising a head ridge which extends in a rearward direction more than an adjacent head portion of the head internal surface located in a radially-inward direction more than the head ridge.

Claims

1. A milling tool comprising: a shank portion; and a head portion extending from the shank portion; a rotation axis extends along the shank portion and defining: a forward direction from the shank portion towards the head portion; a rearward direction opposite to the forward direction; a radially-outward direction perpendicular to the forward and rearward directions and directed outwardly from the rotation axis; a radially-inward direction opposite to the radially outward-direction; a rotation direction; and a counter-rotation direction opposite to the rotation direction; the shank portion comprising: a shank rear end; a shank forward end located closer than the shank rear end to the head portion; and a shank external surface; the head portion comprising: a head external surface; a head internal surface located closer than the head external surface to the shank portion; and a head coolant inlet opening out to the head internal surface; a head coolant outlet opening out to the head external surface; a head coolant passageway extending from the head coolant inlet to the head coolant outlet; the head external surface comprising: a plurality of alternating flutes and cutting portions; each cutting portion comprises a cutting element recess; wherein: the head internal surface is formed with a peripherally extending head coolant obstruction arrangement comprising a head ridge which extends rearward of an adjacent head portion of the head internal surface, the adjacent head portion being located radially inward of the head ridge.

2. The milling tool according to claim 1, wherein the head ridge is shaped as an annular lip.

3. The milling tool according to claim 1, wherein the head coolant obstruction arrangement comprises an additional head ridge which extends rearward of the adjacent head portion and is located radially inward of the adjacent head portion.

4. The milling tool according to claim 3, wherein the additional head ridge is shaped as an annular lip.

5. The milling tool according to claim 1, wherein at the shank rear end, the shank external surface is formed with a peripherally extending shank coolant obstruction arrangement comprising a shank ridge which extends radially outward of an adjacent shank portion of the shank external surface, the adjacent shank portion located forward of the shank ridge.

6. The milling tool according to claim 5, wherein the shank ridge is shaped as an annular lip.

7. The milling tool according to claim 5, wherein the shank coolant obstruction arrangement comprises an additional shank ridge which extends radially outward of the adjacent shank portion and is located forward of the adjacent shank portion.

8. The milling tool according to claim 1, wherein the cutting element recess has a centerpoint and a central plane containing the centerpoint; and the head coolant passageway comprises a linear portion extending to the head coolant outlet, the linear portion defining a passageway plane extending parallel adjacent to the head coolant outlet; wherein the passageway plane is directed more in the forward direction than towards the central plane such that it forms an off-center angle β therewith.

9. The milling tool according to claim 8, wherein the off-center angle β fulfills the condition: 5°<β<40°.

10. The milling tool according to claim 1, wherein the head coolant outlet is elongated.

11. The milling tool according to claim 10, wherein the head coolant outlet is elongated in an elongation direction, a head coolant outlet height HO is measured parallel to an elongation direction, and the milling tool further comprises a cutting element directly adjacent to the head coolant outlet, the cutting element having a cutting element height HC, measured parallel to an elongation direction, fulfilling the condition: 0.1 HC<HO<HC.

12. The milling tool according to claim 1, wherein the head coolant outlet is closer to the cutting element recess than any other adjacent surface of the cutting portion.

13. The milling tool according to claim 12, wherein in a side view of a cutting element, the head coolant outlet is directly adjacent to the cutting element.

14. The milling tool according to claim 1, wherein there are at least eight cutting portions.

15. The milling tool according to claim 1, wherein the milling tool comprises one or more cutting elements which are made of a superhard material.

16. A coolant sleeve having a basic cylindrical shape and comprising: a machine end comprising a connection arrangement; a lower end opposite to the machine end; a sleeve external surface connecting the machine end and the lower end; a sleeve internal surface connecting the machine end and the lower end, and located closer than the sleeve external surface to the shank portion; a sleeve coolant inlet opening out to the sleeve external surface; a sleeve coolant outlet opening out to the sleeve internal surface; a sleeve coolant passageway extending from the sleeve coolant inlet to the sleeve coolant outlet; a sleeve axis defining: a forward direction from the machine end towards the lower end; a rearward direction opposite to the forward direction; a radially-outward direction perpendicular to the forward and rearward directions and directed outwardly from the sleeve axis; and a radially-inward direction opposite to the radially outward-direction; wherein: the lower end is formed with a peripherally extending sleeve coolant obstruction arrangement comprising a sleeve ridge which extends forward of an adjacent sleeve portion of the lower end, the adjacent sleeve portion located radially inward of the sleeve ridge.

17. The coolant sleeve according to claim 16, wherein the sleeve coolant obstruction arrangement comprises an additional sleeve ridge which extends forward of the adjacent sleeve portion, the additional sleeve ridge being located radially inward of the adjacent sleeve portion.

18. A tool assembly comprising: a milling tool according to claim 1; a coolant sleeve having a basic cylindrical shape secured to the milling tool; and at least one cutting element mounted to the milling tool.

19. A tool assembly according to claim 18, wherein the coolant sleeve comprises: a machine end having a connection arrangement; a lower end opposite to the machine end; a sleeve external surface connecting the machine end and the lower end; a sleeve internal surface connecting the machine end and the lower end, and located closer than the sleeve external surface to the shank portion; a sleeve coolant inlet opening out to the sleeve external surface; a sleeve coolant outlet opening out to the sleeve internal surface; a sleeve coolant passageway extending from the sleeve coolant inlet to the sleeve coolant outlet; a sleeve axis defining: a forward direction from the machine end towards the lower end; a rearward direction opposite to the forward direction; a radially-outward direction perpendicular to the forward and rearward directions and directed outwardly from the sleeve axis; and a radially-inward direction opposite to the radially outward-direction; wherein: the lower end is formed with a peripherally extending sleeve coolant obstruction arrangement comprising a sleeve ridge which extends forward of an adjacent sleeve portion of the lower end, the adjacent sleeve portion located radially inward of the sleeve ridge.

20. A tool assembly according to claim 19, wherein the sleeve encircles the shank portion and is spaced-apart therefrom: the sleeve lower end is adjacent to the head internal surface and is spaced-apart therefrom by separation distance SD fulfilling the condition 0.00 mm<SD<1.00 mm.

21. A tool assembly according to claim 20, wherein the separation distance SD fulfills the condition 0.05 mm<SD<0.60 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0054] For a better understanding of the subject matter of the present application, and to show how the same may be carried out in practice, reference will now be made to the accompanying drawings, in which:

[0055] FIG. 1A is a perspective view of a tool assembly according to the present invention;

[0056] FIG. 1B is a perspective side view of the tool assembly in FIG. 1A, with a schematic coolant flow shown exiting the tool assembly to exemplify an exiting direction of the flow if it would not be affected by centrifugal forces;

[0057] FIG. 1C is an exploded side view of the tool assembly in FIG. 1A;

[0058] FIG. 2A is a perspective view of a milling tool of the tool assembly in FIG. 1A;

[0059] FIG. 2B is a top view of the milling tool in FIG. 2A;

[0060] FIG. 2C is a side view of the milling tool in FIG. 2A;

[0061] FIG. 2D is a bottom view of the milling tool in FIG. 2A;

[0062] FIG. 3A is a perspective view of a sleeve of the tool assembly in FIG. 1A;

[0063] FIG. 3B is a top view of the sleeve in FIG. 3A;

[0064] FIG. 3C is a side view of the sleeve in FIG. 3A;

[0065] FIG. 3D is a bottom view of the sleeve in FIG. 3A;

[0066] FIG. 3E is another top view of the sleeve, identical to that shown in FIG. 3B;

[0067] FIG. 3F is a cross-section view taken along line IIIF-IIIF in FIG. 3E;

[0068] FIG. 4A is a perspective view of the tool assembly in FIG. 1, a direction facing a head coolant outlet of the milling tool, with a schematic coolant flow path shown exiting the tool assembly to exemplify an exiting direction of the flow as affected by centrifugal forces;

[0069] FIG. 4B is an enlarged view of the encircled portion designated X in FIG. 4A;

[0070] FIG. 4C is cross-section view of the tool assembly in FIG. 1A; and

[0071] FIG. 5 is a cross-section view of another embodiment of a milling tool according to the present invention.

DETAILED DESCRIPTION

[0072] Referring to FIGS. 1A to 1C, there is illustrated an example tool assembly 10 comprising a milling tool 100 and a sleeve 200 encircling a portion of the milling tool 100 and configured to be relatively static to the milling tool 100 when it is rotating.

[0073] The milling tool 100 (or, alternatively defined, the tool assembly 10) comprises at least one cutting element 300 mounted to the milling tool.

[0074] The cutting elements 300 have flat rake and base surfaces 306, 308 (FIG. 4B) connected by a peripheral edge 310, the flat rake and base surfaces 306, 308 having a basic semi-circular shape. The cutting elements 300 are made of Polycrystalline Diamond (PCD) and in the present example there are twelve cutting elements 300.

[0075] Each cutting element 300 preferably comprises an arc-shaped main cutting edge 302, which extends approximately 180° and which comprises a mid-point 304.

[0076] In FIG. 4B, it is shown that the mounted cutting element 300 has a cutting element height HC, measured parallel to an elongation direction of an adjacent head coolant outlet 134.

[0077] Referring now to also FIGS. 2A to 2D the milling tool 100 comprises a shank portion 102 and a head portion 104 extending from the shank portion 102.

[0078] The rotation axis AR extends along the shank portion 102 and defines a forward direction DF1 from the shank portion 102 towards the head portion 104; a rearward direction DR1 opposite to the forward direction DF1; a radially-outward direction DO1 perpendicular to the forward and rearward directions DF1, DR1 and directed outwardly from the rotation axis AR; a radially-inward direction DI1 opposite to the radially outward-direction D01; a rotation direction DX1; and a counter-rotation direction DY1 opposite to the rotation direction DX1.

[0079] The shank portion 102 comprises a shank rear end 106; a shank forward end 108 located closer than the shank rear end 106 to the head portion 104; and a shank external surface 110.

[0080] At the shank rear end 106, the shank external surface 110 is formed with a peripherally extending shank coolant obstruction arrangement 112 comprising a protruding shank ridge 114 which extends in a radially-outward direction more than an adjacent shank recess portion 116 of the shank external surface, the shank recess portion 116 being located forward of the shank ridge 114. The shank ridge 114 is shaped as a circular annular lip.

[0081] The shank coolant obstruction arrangement 112 also comprises an additional protruding shank ridge 118 located forward of the shank recess portion 116, and shaped as a circular annular lip.

[0082] In embodiments with both the shank ridge 114 and additional shank ridge 118, the adjacent shank recess portion 116 can be considered an annular groove.

[0083] A first additional annular groove 120 is shown rearward of the shank ridge 114, and is forward of another portion 122 of the shank external surface 110.

[0084] A second additional annular groove 124 is shown forward of the additional shank ridge 118, and is rearward of yet another portion 126 of the shank external surface 110.

[0085] The head portion 104 comprises a head external surface 128, a head internal surface 130 located closer than the head external surface 128 to the shank portion 102, and a head coolant inlet 132 opening out to the head internal surface 130; a head coolant outlet 134 opening out to the head external surface 128.

[0086] The head external surface 128 comprising a plurality of alternating flutes 136 and cutting portions 138.

[0087] The head internal surface 130 is further formed with a peripherally extending head coolant obstruction arrangement 140.

[0088] The head coolant obstruction arrangement 140 comprises an upwardly protruding head ridge 142 shaped as a circular annular lip and which extends in the rearward direction DR1 more than an adjacent head portion 144 of the head internal surface located in the radially-inward direction more than the head ridge 142. The transition from the head ridge 142 to the adjacent head portion 144 may be considered a downward and radially inward circumferential step.

[0089] The head coolant obstruction arrangement 140 can further comprise an additional head ridge 146 shaped as a circular annular lip and which extends in the rearward direction DR1 more than the adjacent head portion 144 and is located in the radially-inward direction DI1 more than the adjacent head portion 144. The transition from the adjacent heard portion 144 to the additional head ridge 146 may be considered an upward and radially inward circumferential step.

[0090] In embodiments with both the head ridge 142 and additional head ridge 146, the adjacent head portion 144 can be considered an annular groove.

[0091] Further inward of the head coolant obstruction arrangement 140 is a head reservoir 148 which can be useful in allowing coolant to stabilize and then proceed to enter each head coolant inlet 132.

[0092] Referring now to FIGS. 3A to 3F, the sleeve 200 has a basic cylindrical shape and comprises; a machine (upper) end 202 in turn comprising a connection arrangement 204; a lower end 206 opposite to the machine end 204; a sleeve external surface 208 connecting the machine end 204 and the lower end 206; a sleeve internal surface 210 connecting the machine end 202 and the lower end 206, and located closer than the sleeve external surface 208 to the shank portion 102; a sleeve coolant inlet 212 opening out to the sleeve external surface 208; a sleeve coolant outlet 214 opening out to the sleeve internal surface 210; a sleeve coolant passageway 216 (FIG. 3F) extending from the sleeve coolant inlet 212 to the sleeve coolant outlet 214.

[0093] The connection arrangement 204 comprises a circumferentially spaced plurality of screws 218 housed in recessed areas 220 and extending through screw holes 222 to fasten to a machine interface (not shown).

[0094] Due to the connection to the machine interface (not shown), the sleeve 200 remains static relative to the rotating milling tool 100.

[0095] The sleeve 200 has a sleeve axis AS, which could alternatively be defined with the same directions as the milling tool 100. Since the sleeve axis and rotation axis are coaxial, the directions defined in relation to the milling tool 100 will be used when discussing the tool assembly 10, for convenience only.

[0096] Thus, the sleeve axis AS defines a sleeve forward direction DF2 from the machine end 202 towards the lower end 206; a sleeve rearward direction DR2 opposite to the sleeve forward direction DF2; a sleeve radially-outward direction DO2 perpendicular to the forward and rearward directions DF2, DR2 and directed outwardly from the sleeve axis AS; and a radially-inward direction D12 opposite to the radially outward-direction DO2.

[0097] The sleeve's lower end 206 is formed with a peripherally extending sleeve coolant obstruction arrangement 224 comprising a protruding sleeve ridge 226 shaped as a circular annular lip and which extends in the forward direction more than an adjacent sleeve recess portion 228 of the lower end 206 located in the radially-inward direction more than the sleeve ridge 226.

[0098] The sleeve coolant obstruction arrangement 224 can further comprise an additional sleeve ridge 230 shaped as a circular annular lip and which extends in the sleeve forward direction DF2 more than the adjacent sleeve recess portion 228.

[0099] In embodiments with both the protruding sleeve ridge 226 and additional sleeve ridge 230, the adjacent sleeve recess portion 228 can be considered an annular groove.

[0100] Referring particularly to FIGS. 3E and 3F, the sleeve's internal surface 210 defines a chamber 232.

[0101] The chamber 232 comprises a first (upper) sub-chamber 234 having a diameter slightly larger than the shank portion 102 (to define a gap 240 therebetween as designated in FIG. 4C, however the gap is so small that it is not clearly visible, thus the numeral 240 is merely to assist understanding), a second (middle) sub-chamber 236 slightly larger in diameter than the first sub-chamber 234, and a third (lower) sub-chamber 238 even larger in diameter than the second sub-chamber 236. The sleeve's internal surface 210 tapering in the sleeve radially-outward direction DO2 as it increases in the forward direction DF2. This allows the third sub-chamber 238 to provide a sleeve reservoir 242.

[0102] The sleeve reservoir 242 is believed to be beneficial in stabilizing coolant in order to assist the coolant to enter each head coolant inlet 132.

[0103] The sleeve 200 can optionally comprise connectors 244 (FIG. 1C), configured to attach to the sleeve coolant inlets 212 and supply pipes (not shown). In such case, the sleeve external surface 208 can be formed with a sleeve inlet recess 213 for each sleeve coolant inlet 212.

[0104] Referring now to FIGS. 4A and 4B, the head coolant outlet 134 is elongated in the forward and rearward directions DF1, DF2, and is oval-shaped.

[0105] More precisely, the head coolant outlet 134 has a head coolant outlet height HO and a head coolant outlet width HW which is smaller than the head coolant outlet height HO.

[0106] As shown the head coolant outlet 134 is directly adjacent to the cutting element 300. The head coolant outlet 134 is also closer than a flute centerpoint FC to the cutting element 300. Alternatively defined, the head coolant outlet 134 is also closer than an adjacent surface 150, located in the rotation direction DX1 from the cutting element 300 described, to the cutting element 300.

[0107] Referring now also to FIG. 4C, a head coolant passageway 152 extends from the head coolant inlet 132 to the head coolant outlet 134 and comprising a linear portion 154 extending to the head coolant outlet 134, the linear portion 154 defining a passageway plane PP extending parallel adjacent to the head coolant outlet 134. In the present embodiment the entire head coolant passageway 152 extends in a linear or straight manner, however it will be understood that only a portion thereof which is adjacent to the head coolant outlet 134 determines the direction of coolant flow exiting therefrom.

[0108] The passageway plane PP is directed more in the forward direction than towards the central plane such that it forms an off-center angle β therewith.

[0109] Each cutting portion 138 further comprises a cutting element recess 156 (FIG. 1C) which is recessed in the counter-rotation direction and has a centerpoint CP (FIG. 1C; shown schematically on the cutting element for explanatory purposes only in FIG. 4C); and a central plane PC containing the centerpoint CP.

[0110] Notably, the coolant flow path FP is shown in FIG. 4C. The coolant (not shown) enters the sleeve coolant passageway 216 until it impacts the shank portion 102 and enters the second sub-chamber 236 (since a gap between the shank portion 102 and the sleeve 200 is designed to be smaller at the first sub-chamber 234 so that the coolant will be redirected at a first bend 158 towards the head portion 104 in the forward direction DF1). The shank coolant obstruction arrangement 112 further assists in reducing coolant from exiting in the rearward direction DR1 by impeding coolant flow.

[0111] Subsequent to the first bend 158 the coolant reaches said head reservoir 148 and sleeve reservoir 242 (which coincide) and consequently enters each head coolant inlet 132. The sleeve and head coolant obstruction arrangements 140, 224 assist in reducing coolant from exiting in the radially outward direction DO1 and rearward direction DR1.

[0112] After the coolant exits the head coolant outlet 134 the coolant flow path FP comprises a second bend 160 caused by centrifugal forces, which thus directs the coolant more towards the centerpoint CP of the cutting element recess 156 along the central plane PC, than the initial direction from the head coolant outlet 134 along the passageway plane PP. In FIG. 1B there is a schematic coolant flow 162 shown that would be the direction of the coolant if it would not be affected by centrifugal forces (and therefore it would not cool most of the cutting element 300, however this will not be the case due to the high rotational speed of the milling tool 100).

[0113] Notably, the sleeve lower end is adjacent to the head internal surface and is spaced-apart therefrom by separation distance SD.

[0114] Referring to FIG. 5, there is shown another embodiment of the milling tool 1000, it will be understood that the only substantive difference are the head coolant passageways and shapes thereof. In this example there are three head coolant passageways 1002, 1004, 1006 per flute or cutting portion, each having a traditional circular cross section, including circular outlet holes.