Milling head with through-bore having centering surface and driving surface at tooth receiving lobes, tool holder and rotary milling tool

Abstract

A rotary milling tool has a tool holder and a milling head releasably attachable to the tool holder. The milling head has a head through recess that opens outwardly to a head front surface and a head back surface. The recess includes a plurality of radially extending tooth receiving lobes. The tool holder has a protrusion including a plurality of radially extending teeth. When assembled, the teeth are located in the tooth receiving lobes and provide centering and torque transmitting capabilities.

Description

Technical Field

[0001] This application relates to rotary milling tools having a milling head (which has multiple peripherally arranged cutting portions), and particularly to such milling heads having a through hole. The through hole has multiple driven surfaces for transmitting torque from a tool holder and multiple radially centering surfaces for radial alignment of the milling head with the tool holder. Background Technology

[0002] A rotary milling cutter may include a milling head that is releasably clamped to a tool holder by at least one fastening member (e.g., a set screw). The milling head may have multiple peripherally arranged cutting portions. The milling head may have a through-hole for engaging a protrusion to provide radial centering of the milling head relative to the tool holder. Typically, the through-hole is cylindrical. The milling head may have a keyway extending radially outward from the through-hole for receiving a key that provides torque transmission from the tool holder to the milling head.

[0003] Various such cutting tools and milling heads are disclosed in JP2021094680 A, DE202017105606 U1 and US 7,153,068.

[0004] The subject of this application is to provide an improved and compact engagement between the milling head and the tool holder. Summary of the Invention

[0005] According to a first aspect of the subject matter of this application, a milling head is provided having a head central axis defining opposite forward and backward directions, and the milling head is rotatable about the head central axis in a rotational direction (R), the milling head comprising: Opposite front and rear surfaces of the head and an outer peripheral surface of the head extending between them, the outer peripheral surface of the head extending circumferentially around the central axis of the head; Multiple cutting portions spaced at an angle on the outer periphery; and A head-penetrating recess extends along the central axis of the head and opens outward to the front and rear surfaces of the head. The head-penetrating recess is circumferentially defined by its outer peripheral surface and includes a plurality of radially outwardly extending, angledly spaced toothed receiving flaps; wherein: The outer peripheral surface of the recess includes multiple driven surfaces and multiple radially centering surfaces. These surfaces are located at multiple tooth receiving flaps and are configured to abut against corresponding surfaces on the tool holder. Each driven surface faces in the opposite direction to the rotation direction, and each radially centering surface faces radially inward. Multiple radially centering surfaces are radially outwardly positioned from multiple driven surfaces.

[0006] According to a second aspect of the subject matter of this application, a tool holder is provided having a retainer central axis defining opposite forward and rearward directions, and the tool holder is rotatable about the retainer central axis in a rotational direction, the tool holder comprising: The outer peripheral surface of the handle extends circumferentially around the central axis of the retainer; The front end surface of the shank, which is defined by the outer peripheral surface of the shank located at the front end of the tool holder; and A handle protrusion extending from the front end surface of the handle along the central axis of the retainer, the handle protrusion being circumferentially defined by its outer peripheral surface and including a plurality of radially outwardly extending, angledly spaced centering drive teeth; wherein: The outer peripheral surface of the protrusion includes multiple driving surfaces and multiple radial alignment surfaces, all located at multiple centering drive teeth and configured to abut against corresponding surfaces on the milling head. Each driving surface faces the direction of rotation, and each radial alignment surface faces radially outward. Multiple radial alignment surfaces are radially outwardly positioned from multiple drive surfaces.

[0007] According to a third aspect of the subject matter of this application, a rotary milling tool is provided, comprising: The above-mentioned types of milling heads; and The above-mentioned types of tool holders; in: The milling head can be releasably attached to the tool holder; The handle protrusion is located in the head through recess; Multiple radial centering surfaces directly abut against multiple radial alignment surfaces of the connecting portion; and Multiple driven surfaces directly abut against multiple driving surfaces.

[0008] It should be understood that the above is an overview, and the features described below may be applied to the subject matter of this application in any combination. For example, any one of the following features may be applied to a milling head, a tool holder, or a rotary milling tool.

[0009] The outer peripheral surface of the recess can be oriented parallel to the central axis of the head.

[0010] The radial centering surface is oriented at the centering surface angle along the head's central axis. The centering surface angle can be greater than or equal to 20° and less than or equal to 40°.

[0011] The through-recess may include a plurality of radially spaced-apart recesses that alternate circumferentially with the tooth receiving flaps along the outer peripheral surface of the recess. The outer peripheral surface of the recess may include a plurality of recess gap surfaces, each located at a corresponding radially narrowed recess and facing radially inward.

[0012] The surfaces of multiple recessed gaps can be convex.

[0013] Multiple radially centered surfaces can be concave.

[0014] Multiple radially centered surfaces can define the outermost cylinder of the imaginary recess centered on the head's central axis.

[0015] Multiple radially centered surfaces can be located on the inner surface of the outermost cylinder of the imaginary concave portion.

[0016] Multiple recessed gap surfaces can define an imaginary innermost cylinder coaxial with the imaginary outermost cylinder of the recess. The imaginary innermost cylinder has the radius of the imaginary innermost cylinder. The imaginary outermost cylinder has the radius of the imaginary outermost cylinder. The radius of the innermost cylinder can be less than or equal to 75% of the radius of the outermost cylinder.

[0017] The milling head may include a plurality of angledly spaced fastening through holes that open outward to the front and rear surfaces of the head and are spaced apart from the head through recess. Each fastening through hole may be located between two angledly adjacent tooth receiving flaps in the head through recess.

[0018] Multiple fastening through holes can be located inside the outermost cylinder of the imaginary recess or intersect with the outermost cylinder of the imaginary recess.

[0019] Each fastening through-hole extends along its corresponding fastening through-hole axis. The fastening through-hole axis can be located inside the outermost cylinder of the imaginary recess.

[0020] The outer peripheral surface of the recess has a recess height as measured in the axial direction. Multiple radial centering surfaces and multiple driven surfaces can extend the entire recess height.

[0021] The head through recess can include exactly three teeth to receive the leaflets.

[0022] Each toothed receiving flap can have exactly one driven surface and exactly one radial centering surface located thereon.

[0023] The milling head may include a plurality of angledly spaced chip flutes that alternate circumferentially with a plurality of cutting portions along the outer peripheral surface of the head, each chip flute opening outward to at least one of the front and rear surfaces of the head. Each cutting portion may include an insert receiving recess.

[0024] The rear surface of the head may include at least one rearward-facing planar axial support surface extending along its entire angular range.

[0025] Each tooth receiving flap may include a flap narrowing portion and a flap widening portion located radially outside the flap narrowing portion. The flap widening portion has a maximum first width, and the flap narrowing portion has a maximum second width. The maximum first width may be greater than the maximum second width.

[0026] The head-through recess may include a central region connected to multiple toothed receiving flaps. The radial length of each toothed receiving flap from the central region may exceed the radial range of the central region.

[0027] The outer peripheral surface of the protrusion can be oriented parallel to the longitudinal axis of the retainer.

[0028] Each radial alignment surface can be aligned with an alignment surface angle at the longitudinal axis of the retainer. The alignment surface angle can be greater than or equal to 20° and less than or equal to 40°.

[0029] The shank protrusion may include a plurality of radially spaced-apart radially narrowed portions, which alternate circumferentially with the centering drive teeth along the outer peripheral surface of the protrusion. The outer peripheral surface of the protrusion may include a plurality of protrusion gap surfaces, each located at a corresponding radially narrowed portion and oriented radially outward.

[0030] The surfaces of the gaps between multiple protrusions can be concave.

[0031] The radial alignment surface can be convex.

[0032] The radial alignment surface can define the outermost cylinder of the imaginary protrusion centered on the central axis of the retainer.

[0033] The radial alignment surface can be located on the outer surface of the outermost cylinder of the imaginary protrusion.

[0034] Multiple protrusion gap surfaces can define an innermost imaginary cylinder coaxial with the outermost cylinder of the imaginary protrusion. The innermost cylinder of the imaginary protrusion has the radius of the innermost cylinder of the protrusion. The outermost cylinder of the imaginary protrusion has the radius of the outermost cylinder of the protrusion. The radius of the innermost cylinder of the protrusion can be less than or equal to 75% of the radius of the outermost cylinder of the protrusion.

[0035] The tool retainer may include a plurality of angled, spaced-apart threaded holes that open outward to the front end surface of the shank and are spaced apart from the shank protrusion. Each threaded hole may be located between two angled, adjacent centering drive teeth.

[0036] Multiple threaded holes may be located inside the outermost cylinder of the imaginary protrusion or intersect with the outermost cylinder of the imaginary protrusion.

[0037] Each threaded hole extends along its corresponding threaded hole axis. The threaded hole axis can be located inside the outermost cylinder of the imaginary protrusion.

[0038] The outer peripheral surface of the protrusion has a protrusion height as measured in the axial direction. Multiple radial alignment surfaces and multiple drive surfaces extend throughout the entire protrusion height.

[0039] The shank protrusion may include exactly three centering drive teeth.

[0040] Each centering drive tooth can have exactly one drive surface and exactly one radial alignment surface located thereon.

[0041] The front end surface of the handle may include at least one forward-facing planar axial support surface extending along its entire angular range.

[0042] At least one axial support surface may abut against at least one axial support surface.

[0043] The milling head can be releasably clamped to the tool holder by multiple threaded fasteners, each threaded fastener located in a corresponding fastening through hole and threadedly engaged with a corresponding threaded hole. Attached Figure Description

[0044] To better understand this application and to show how it can be implemented in practice, reference will now be made to the accompanying drawings, in which: Figure 1 This is a perspective view of a rotary milling tool according to this application; Figure 2 yes Figure 1 An exploded perspective view of the rotary milling tool shown; Figure 3 yes Figure 1 The front view of the milling head shown reveals five hidden head coolant channels; Figure 4 yes Figure 3 The rear view of the milling head shown reveals five hidden head coolant channels; Figure 4a yes Figure 4 Details; Figure 5 yes Figure 3 The side view of the milling head shown; Figure 6 This is a perspective view of the front end of the tool holder according to this application; Figure 7 yes Figure 6 The front view of the tool holder shown; Figure 8 yes Figure 6 The side view of the front end of the tool holder shown illustrates three concealed retainer coolant channels that open outwards into a concealed radial retraction recess; Figure 9 yes Figure 1 The front end view of the rotary milling cutter shown; Figure 10 yes Figure 1 A side view of the front end of the rotary milling cutter shown; Figure 11 It was intercepted along line XX. Figure 9 An axial cross-sectional view of the rotary milling cutter shown; Figure 12 It is a segment taken along line YY. Figure 10 A radial sectional view of the rotary milling cutter shown; and Figure 13 It was intercepted along line ZZ. Figure 10 The radial cross-sectional view of the rotary milling cutter shown.

[0045] It should be recognized that, for the sake of simplicity and clarity, the elements shown in the accompanying drawings are not necessarily drawn to scale. For example, for clarity, the dimensions of some elements may be exaggerated relative to others, or several physical components may be included in a single functional block or element. Furthermore, reference numerals may be repeated in the drawings where deemed appropriate to indicate corresponding or similar elements. Detailed Implementation

[0046] In the following description, various aspects of the subject matter of this application will be described. For purposes of illustration, specific constructions and details are set forth in sufficient detail to provide a thorough understanding of the subject matter of this application. However, it will also be apparent to those skilled in the art that the subject matter of this application can be practiced without the specific constructions and details set forth herein.

[0047] First, pay attention Figure 1 and Figure 2 , Figure 1 and Figure 2 A rotary milling cutter 20 depicting one aspect of this application is shown. In this non-limiting example shown in the figures, the rotary milling cutter 20 can form a grooving saw suitable for grooving cutting operations. The rotary milling cutter 20 has a tool center axis A. The rotary milling cutter 20 has a tool holder 22, which is typically made of steel. The rotary milling cutter 20 has a milling head 24, which is typically made of steel. The milling head 24 is releasably attached to the tool holder 22.

[0048] Still referencing Figures 3 to 5This illustrates another aspect of the subject matter of this application related to the milling head 24. The milling head 24 has a head center axis B. The head center axis B defines an opposite forward direction D. F and backward direction D R The central axis B of the milling head forms a rotation axis, and the milling head 24 can rotate around this rotation axis in the rotation direction R, where the rotation direction R is the cutting direction.

[0049] It should be recognized that in the following discussion of the milling head 24, the terms "forward" and "backward" are used throughout the specification and claims to refer to... Figure 5 The head's central axis B points to the left (or backward) D. R ) and to the right (or forward direction D) F The relative position on the head. In addition, unless otherwise stated, the terms "axial" and "radial" are relative to the head center axis B.

[0050] The blank used to make the milling head 24 may be additively manufactured. It should be noted that the term "additive manufacturing," as used throughout the specification and claims, refers to the type of part formed using one or more additive manufacturing processes to create a three-dimensional object by forming layers of material within the object. Examples of such additive manufacturing processes include, but are not limited to, selective laser melting (SLM), selective laser sintering (SLS), direct metal laser sintering (DMLS), fused deposition modeling (FDM), and 3D printing.

[0051] like Figures 3 to 5 As shown, the milling head 24 includes opposing front and rear surfaces 26 and an outer peripheral surface 30 extending between them. The front surface 26 is axially anterior to the rear surface 28. The outer peripheral surface 30 extends circumferentially about the head's central axis B. Generally, the outer peripheral surface 30 is radially outward. Some embodiments according to the subject matter of this application, such as... Figure 6 As shown, the milling head 24 may be shorter in the axial direction than in the radial direction. The front surface 26 and the rear surface 28 of the head may be parallel to each other and oriented perpendicular to the head central axis B. The milling head 24 may have a basic disc-shaped shape defined by the front surface 26, the rear surface 28, and the outer peripheral surface 30 of the head.

[0052] refer to Figure 3 and Figure 4The milling head 24 includes a plurality of radially outwardly extending, angledly spaced cutting portions 40. According to some embodiments of the subject matter of this application, each cutting portion 40 may include an insert receiving recess 108 for accommodating a cutting insert 110. The cutting insert 110 includes a cutting edge 32. The milling head 24 may include a plurality of angledly spaced chip grooves 42 for discharging chips. The plurality of chip grooves 42 are recessed (radially inward) in the outer peripheral surface 30 of the head and alternate circumferentially with the plurality of cutting portions 40 along the outer peripheral surface 30 of the head. According to some embodiments of the subject matter of this application, each chip groove 42 may open outwardly to a front surface 26 and a rear surface 28 of the head.

[0053] The milling head 24 includes a head through recess 44 that opens outwardly to a front surface 26 and a rear surface 28. The head through recess 44 extends along a central axis B of the head and is therefore centrally located. In other words, the central axis B passes through the head through recess 44. The head through recess 44 is circumferentially defined by an outer peripheral surface 46. The outer peripheral surface 46 extends circumferentially about the central axis B of the head. Generally, the outer peripheral surface 46 faces radially inward. According to some embodiments of the subject matter of this application, the outer peripheral surface 46 may be oriented parallel to the central axis B of the head. Reference Figure 5 The outer peripheral surface 46 of the recess may have a recess height H as measured in the axial direction (i.e., along the head center axis B). The recess height H may be constant along the outer peripheral surface 46 of the recess. The recess height H may be the same as the axial thickness of the milling head 24.

[0054] refer to Figure 3 , Figure 4 and Figure 4aThe milling head 24 includes a plurality of angledly spaced drive protrusions 60 extending radially inward into a head through recess 44. Therefore, the head through recess 44 is non-cylindrical. Specifically, the head through recess 44 includes a central region 51 connected to a plurality of angledly spaced tooth receiving flaps 48. Each drive protrusion 60 is located between two adjacent tooth receiving flaps 48. The tooth receiving flaps 48 extend radially outward. Each tooth receiving flap 48 includes a flap narrowing portion LN and a flap widening portion LW located radially outside the flap narrowing portion LN. Therefore, each tooth receiving flap 48 can have a non-rectangular shape, such as a pear shape. Due to the drive protrusions 60, the head through recess 44 includes a plurality of angledly spaced radially narrowed recesses 50. The tooth receiving flaps 48 are designed to receive drive teeth, as described below. Multiple radially narrowed recesses 50 alternate circumferentially with tooth-receiving flaps 48 along the outer peripheral surface 46 of the recess. The outer peripheral surface 46 of the recess is further away from the head central axis B at the tooth-receiving flaps 48 than at the radially narrowed recesses 50. In this non-limiting example shown in the figures, the milling head 24 includes exactly three drive protrusions 60 (although other numbers of drive protrusions 60 are also contemplated). Thus, the head through recess 44 includes exactly three tooth-receiving flaps 48 and exactly three radially narrowed recesses 50. The multiple drive protrusions 60 and the multiple tooth-receiving flaps 48 may be identical.

[0055] The outer peripheral surface 46 of the recess includes a plurality of driven surfaces 58, each driven surface 58 associated with a corresponding tooth receiving flap 48. The plurality of driven surfaces 58 are configured to transmit torque by direct abutment against a corresponding surface on the tool holder 22. The plurality of driven surfaces 58 may be planar. Each driven surface 58 faces a direction opposite to the direction of rotation R. Each driven surface 58 is located at a corresponding tooth receiving flap 48. Preferably, each tooth receiving flap 48 has exactly one driven surface 58 located thereon.

[0056] The outer peripheral surface 46 of the recess includes a plurality of radially centered surfaces 62, each radially centered surface 62 being associated with a corresponding tooth receiving flap 48. The plurality of radially centered surfaces 62 are designed to center the milling head 24 relative to the tool holder 22 such that the two parts are coaxial during assembly. Each radially centered surface 62 faces radially inward. Each radially centered surface 62 is located at a corresponding tooth receiving flap 48. Preferably, each tooth receiving flap 48 has exactly one radially centered surface 62 located thereon.

[0057] The plurality of radially centering surfaces 62 may be concave. It should be understood that the term “convex / concave” as used throughout the specification and claims includes a surface that is continuously (i.e., smoothly) convexly / concavely curved, or consists of a plurality of straight sub-surfaces that provide the convex / concave shape to the surface. Preferably, the plurality of radially centering surfaces 62 may be continuously concavely curved.

[0058] refer to Figure 4a According to some embodiments of the subject matter of this application, a plurality of radially centering surfaces 62 may define an outermost cylinder OC of an imaginary recess centered on the head central axis B. The outermost cylinder OC of the imaginary recess may be a circumscribed cylinder. The plurality of radially centering surfaces 62 may be located on the inner surfaces of the outermost cylinder OC of the imaginary recess. The outermost cylinder OC of the imaginary recess defines a plurality of toothed receiving flaps 48 in a radially outward direction. Similarly, the outermost cylinder OC of the imaginary recess may define the boundaries of a plurality of protrusions 60 in a radially outward direction. The outermost cylinder OC of the imaginary recess has a recess outermost cylinder radius OR.

[0059] According to some embodiments of the subject matter of this application, the radial centering surface 62 can be oriented towards the centering surface angle α at the head central axis B. The centering surface angle α can satisfy the condition: 20°≤α≤40°. Preferably, the centering surface angle α can satisfy the condition: 25°≤α≤35°.

[0060] In each tooth-receiving leaflet 48, the wider portion LW is wider in the circumferential direction than the narrower portion LN. For example... Figure 4a As seen, the widening portion LW has a maximum first width w1, while the narrowing portion LN has a maximum second width w2, where w1 > w2. Preferably, w1 ≥ 1.20 * w2 (i.e., w1 is at least 20% longer than w2). More preferably, w1 ≤ 1.80 * w2 (i.e., w1 is at most 80% longer than w2). Here, the leaf widths w1 and w2 are shown as measured in a direction perpendicular to the radial line R1 that intersects the central axis B of the head and bisects the centering angle α, and represent the circumferential width at the widening portion LW and the narrowing portion LN.

[0061] Multiple radially centering surfaces 62 are radially outwardly positioned from multiple driven surfaces 58. According to some embodiments of the subject matter of this application, the multiple radially centering surfaces 62 and the multiple driven surfaces 58 may extend throughout the entire recess height H.

[0062] According to some embodiments of the subject matter of this application, the outer peripheral surface 46 of the recess may include a plurality of recess gap surfaces 66. Each recess gap surface 66 may be located at a corresponding radially narrowed recess 50. Each recess gap surface 66 may face radially inward. The plurality of recess gap surfaces 66 may be convex. Preferably, the plurality of recess gap surfaces 66 may be continuously convexly curved. More preferably, the plurality of recess gap surfaces 66 may be located on the inner surfaces of different imaginary cylinders (not shown) that are not centered on the head central axis B.

[0063] refer to Figure 4a According to some embodiments of the subject matter of this application, a plurality of recessed gap surfaces 66 may define an imaginary innermost cylinder IC coaxial with the imaginary outermost cylinder OC of the recess. The imaginary innermost cylinder IC may be an inscribed cylinder. The plurality of recessed gap surfaces 66 may contact (but not extend across) the imaginary innermost cylinder IC. The imaginary innermost cylinder IC has a recessed innermost cylinder radius IR. The recessed innermost cylinder radius IR may be less than or equal to 75% of the recessed outermost cylinder radius OR. Preferably, the recessed innermost cylinder radius IR may be less than or equal to 50% of the recessed outermost cylinder radius OR. The imaginary innermost cylinder IC, having a recessed innermost cylinder radius IR, may define the extent of the head penetrating the central region 51 of the recess 44. A plurality of drive protrusions 60 may terminate at the central region 51 in a radially inward direction. Furthermore, since the outermost cylinder radius OR of the recess is greater than the innermost cylinder radius IR of the recess, the radial length of each tooth receiving leaflet 48 (starting from the central region 51) exceeds the radial range of the central region 51 itself.

[0064] According to some embodiments of the subject matter of this application, the milling head 24 may include a plurality of fastening through holes 67 that open outward to the front surface 26 and the rear surface 28 of the head. The fastening through holes 67 are designed to receive fastening members (e.g., retaining screws) for attaching the milling head 24 to the tool holder 24. Preferably, the number of fastening through holes 67 matches the number of drive protrusions 60.

[0065] According to some embodiments of the subject matter of this application, a plurality of fastening through holes 67 may be spaced at an angle around the head central axis B. The plurality of fastening through holes 67 may be spaced apart from the head through recess 44.

[0066] Each fastening through-hole 67 extends along a corresponding fastening through-hole axis F. According to some embodiments of the subject matter of this application, each fastening through-hole 67 includes a fastening hole outer peripheral surface 67a extending around the fastening through-hole axis F. Each fastening through-hole 67 may be rotationally symmetrical about its fastening through-hole axis F. In particular, the fastening hole outer peripheral surface 67a may be cylindrical. When viewed along the fastening through-hole axis F, the fastening hole outer peripheral surface 67a may define a see-through portion through the fastening through-hole 67. The fastening through-hole 67 may open outwardly via a chamfer to the front surface 26 to receive a screw head (see...). Figure 3 and Figure 4 ).

[0067] refer to Figure 4a Each fastening through-hole 67 can be located between two angled adjacent tooth receiving flaps 48 (of the head penetrating recess 44). Multiple fastening through-holes 67 can be located inside or intersect with the outermost cylinder OC of the imaginary recess. In other words, multiple fastening through-holes 67 may also not be located outside the outermost cylinder OC of the imaginary recess. The axis F of the fastening through-holes can be located inside the outermost cylinder OC of the imaginary recess. A large portion of the outer peripheral surface 67a of each fastening through-hole 67 can be located on the corresponding drive protrusion 60.

[0068] like Figure 11 As best seen in some embodiments of the subject matter of this application, the rear surface 28 may include at least one rearward-facing axial support surface 64a, 64b. The at least one axial support surface 64a, 64b is designed to position the milling head 24 in a predetermined axial position relative to the tool holder 22. The at least one axial support surface 64a, 64b may be planar and oriented perpendicular to the head's central axis B. The at least one axial support surface 64a, 64b may extend along the entire angular range (i.e., 360°) of the rear surface 28. In this non-limiting example shown in the figures, the rear surface 28 may include a first axial support surface 64a and a second axial support surface 64b. The first axial support surface 64a and the second axial support surface 64b are radially spaced apart, wherein the first axial support surface 64a is positioned radially outward from the second axial support surface 64b. The first axial support surface 64a and the second axial support surface 64b may be coplanar with each other.

[0069] refer to Figure 3 and Figure 4According to some embodiments of the subject matter of this application, the milling head 24 may include a plurality of head coolant channels 69 (the outline of which is indicated by dashed lines) for guiding coolant toward the cutting area. Each head coolant channel 69 has a head channel inlet 69a and a head channel outlet 69b, the head channel inlet 69a being located on the rear surface 28 of the head and the head channel outlet 69b being located on the outer peripheral surface 30 of the head. In this non-limiting example shown in the accompanying drawings, each head channel outlet 69b is located at a corresponding chip groove 42.

[0070] Now for reference Figures 6 to 8 The image shows a tool holder 22, illustrating a second aspect of the invention. The tool holder 22 has a retainer central axis C. The tool holder 22 may be elongated along the retainer central axis C. The retainer central axis C is in the forward direction D. F and backward direction D R Extending upwards. The central axis C of the retainer forms a rotation axis, and the tool retainer 22 can rotate about this rotation axis in the rotation direction R.

[0071] It should be understood that in the following discussion of the tool holder 22, the terms "forward" and "backward" are used throughout the specification and claims to refer to... Figure 8 The relative positions of the retainer's central axis C in the downward and upward directions. Furthermore, unless otherwise stated, the terms "axial" and "radial" are relative to the retainer's central axis C.

[0072] The tool retainer 22 has a shank peripheral surface 72 extending circumferentially around the retainer's central axis C. The tool retainer includes a shank front end surface 70 defined by the shank peripheral surface 72. The shank peripheral surface 72 may be cylindrical and defines a shank diameter D.

[0073] refer to Figure 6 The tool holder 22 includes a shank protrusion 74 that extends from the front end surface 70 of the shank along the central axis C of the holder. The shank protrusion 74 is circumferentially defined by an outer peripheral surface 76. The outer peripheral surface 76 extends circumferentially about the central axis C of the holder. Generally, the outer peripheral surface 76 is radially outward. According to some embodiments of the subject matter of this application, the outer peripheral surface 76 may be oriented parallel to the longitudinal axis C of the holder. The outer peripheral surface 76 may have a protrusion height H' as measured in the axial direction (i.e., along the central axis C of the holder). The protrusion height H may be constant along the outer peripheral surface 76.

[0074] Reference Figure 7The shank protrusion 74 includes a plurality of angledly spaced centering drive teeth 78 extending radially outward. The shank protrusion 74 also includes a plurality of angledly spaced radially spaced protrusion narrowings 80, which alternate circumferentially with the centering drive teeth 78 along the outer peripheral surface 76 of the protrusion. The outer peripheral surface 76 of the protrusion is further away from the retainer's central axis C at the centering drive teeth 78 than at the radially spaced protrusion narrowings 80. In this non-limiting example shown in the figures, the shank protrusion 74 includes exactly three centering drive teeth 78 and exactly three radially spaced protrusion narrowings 80. Adjacent pairs of centering drive teeth 78 may be spaced apart by tooth gaps 79. The plurality of centering drive teeth 78 may be identical.

[0075] The outer peripheral surface 76 of the protrusion includes a plurality of drive surfaces 82 for direct contact with a plurality of driven surfaces 58. When the tool holder 22 rotates about the holder's central axis C, torque is transmitted to the milling head 24 via the drive surfaces 82. The plurality of drive surfaces 82 may be planar. Each drive surface 82 faces the direction of rotation R. Each drive surface 82 is located at a corresponding centering drive tooth 78. Preferably, each centering drive tooth 78 has exactly one drive surface 82 located thereon.

[0076] The outer peripheral surface 76 of the protrusion includes a plurality of radial alignment surfaces 84 for directly abutting against a plurality of radial centering surfaces 62. Each radial alignment surface 84 is radially outward. Each radial alignment surface 84 is located at a corresponding centering drive tooth 78. Preferably, each centering drive tooth 78 has exactly one radial alignment surface 84 located thereon.

[0077] The plurality of radial alignment surfaces 84 may be convex. Preferably, the plurality of radial alignment surfaces 84 may be continuously convexly curved.

[0078] refer to Figure 7 According to some embodiments of the subject matter of this application, the radial alignment surface 84 may define an outermost cylinder OC' of the imaginary protrusion centered on the central axis C of the retainer. The outermost cylinder OC' of the imaginary protrusion may be a circumscribed cylinder. A plurality of radial alignment surfaces 84 may be located on the outer surface of the outermost cylinder OC' of the imaginary protrusion. The outermost cylinder OC' of the imaginary protrusion has a radius OR' of the outermost cylinder of the protrusion. The outermost cylinder OC' of the imaginary protrusion defines each tooth gap 79 in a radially outward direction.

[0079] According to some embodiments of the subject matter of this application, each radial alignment surface 84 can be aligned with an alignment surface angle β at the longitudinal axis C of the retainer. The alignment surface angle β can satisfy the condition: 20° ≤ β ≤ 40°. Preferably, the alignment surface angle β can satisfy the condition: 25° ≤ β ≤ 35°.

[0080] Multiple radial alignment surfaces 84 are radially outwardly positioned from multiple drive surfaces 82. According to some embodiments of the subject matter of this application, the multiple radial alignment surfaces 84 and the multiple drive surfaces 82 may extend over the entire height H' of the protrusion.

[0081] According to some embodiments of the subject matter of this application, the outer peripheral surface 76 of the protrusion may include a plurality of protrusion gap surfaces 86. Each protrusion gap surface 86 may be located at a corresponding radially narrowed portion 80 of the protrusion. Each protrusion gap surface 86 may be radially outward. The plurality of protrusion gap surfaces 86 may be concave. Preferably, the plurality of protrusion gap surfaces 86 may be continuously concavely curved.

[0082] Refer again Figure 7 According to some embodiments of the subject matter of this application, a plurality of protrusion gap surfaces 86 may define an imaginary innermost cylinder IC' coaxial with the imaginary outermost cylinder OC' of the protrusion. The imaginary innermost cylinder IC' may be an inscribed cylinder. The plurality of protrusion gap surfaces 86 may contact (but not extend across) the imaginary innermost cylinder IC'. The imaginary outermost cylinder OC' defines a plurality of centering drive teeth 78 in a radially inward direction. The imaginary innermost cylinder IC' has a protrusion innermost cylinder radius IR'. The protrusion innermost cylinder radius IR' may be less than or equal to 75% of the protrusion outermost cylinder radius OR'. Preferably, the protrusion innermost cylinder radius IR' may be less than or equal to 50% of the protrusion outermost cylinder radius OR'.

[0083] According to some embodiments of the subject matter of this application, the tool holder 22 may include a plurality of threaded holes 88 that open outward to the front end surface 70 of the shank. The threaded holes 88 are used to threadedly receive fastening members 68, as discussed below. Preferably, the number of threaded holes 88 matches the number of centering drive teeth 78.

[0084] Each threaded hole 88 extends along a corresponding threaded hole axis G. According to some embodiments of the subject matter of this application, the plurality of threaded holes 88 may be spaced at an angle around the central axis C of the retainer. The plurality of threaded holes 88 may be spaced apart from the shank protrusion 74.

[0085] refer to Figure 7Each threaded hole 88 can be located between two angled adjacent centering drive teeth 78. Multiple threaded holes 88 can be located inside or intersect with the outermost cylinder OC' of the imaginary protrusion. The threaded hole axis G can be located inside the outermost cylinder OC' of the imaginary protrusion. A majority of each threaded hole 88 can be located within the corresponding tooth clearance 79. Advantageously, positioning multiple threaded holes 88 closer to the retainer's central axis C (e.g., such that they are at least partially located within the tooth clearance 79) allows for a reduction in the shank diameter D. Therefore, for any given tool diameter, the depth of cut of the groove can be increased.

[0086] like Figure 11 As best seen in some embodiments of the subject matter of this application, the shank front end surface 70 may include at least one forward-facing axial support surface 90a, 90b. The at least one axial support surface 90a, 90b may be planar and oriented perpendicular to the retainer central axis C. The at least one axial support surface 90a, 90b may extend along the entire angular range (i.e., 360°) of the shank front end surface 70. In this non-limiting example shown in the figures, the shank front end surface 70 may include a first axial support surface 90a and a second axial support surface 90b. The first axial support surface 90a and the second axial support surface 90b may be radially spaced apart by a radially recessed retraction recess 94 in the shank front end surface 70, wherein the first axial support surface 90a is positioned radially outward from the second axial support surface 90b. The radially recessed retraction recess 94 may be recessed along the entire angular range (i.e., 360°) of the shank front end surface 70. The first axial support surface 90a and the second axial support surface 90b may be coplanar with each other. Multiple threaded holes 88 can open outward in the radial retraction recess 94. A second axial support surface 90b can surround the shank protrusion 74.

[0087] refer to Figure 8 According to some embodiments of the subject matter of this application, the tool holder 22 may include a plurality of holder coolant channels 92 for feeding coolant into the head coolant channel 69. Each holder coolant channel 92 has a holder coolant channel outlet 92b for discharging coolant, which may be located on the shank front end surface 70. In particular, the holder coolant channel outlet 92b may be located in a radial retraction recess 94.

[0088] refer to Figure 1 and Figure 2The milling head 24 is releasably clamped to the tool holder 22 by a plurality of fastening members 68 to form an assembled state of the rotary milling tool 20. According to some embodiments of the subject matter of this application, each fastening member 68 may be an integrally formed retaining screw having an integral monolithic (“monolithic”) construction with external threads 104. That is, each fastening member 68 may be “threaded”.

[0089] Now for reference Figures 9 to 13 In the assembled position of the rotary milling cutter 20, the shank protrusion 74 is located in the head through recess 44. Each threaded fastening member 68 is located in a corresponding fastening through hole 67 and threadedly engages with a corresponding threaded hole 88. The centering drive tooth 78 is located in the tooth receiving flap 48 of the head through recess 44 of the milling head. A plurality of driven surfaces 58 directly abut against a plurality of drive surfaces 82. A plurality of radial centering surfaces 62 directly abut against a plurality of radial alignment surfaces 84. According to some embodiments of the subject matter of this application, at least one axial support surface 64a, 64b may abut against at least one axial support surface 90a, 90b. The plurality of recess clearance surfaces 66 may also not abut against the plurality of protrusion clearance surfaces 86.

[0090] refer to Figure 11 and Figure 12 According to some embodiments of the subject matter of this application, in the assembled position of the rotary milling cutter 20, the radial retraction recess 94 can be partially sealed by the head rear surface 28, thereby forming a coolant reservoir 96. In this non-limiting example shown in the figures, the seal is formed by the first axial support surface 64a and the second axial support surface 64b abutting against the first axial support surface 90a and the second axial support surface 90b, respectively. The head channel inlet 69a can be located on the head rear surface 28 such that the head coolant channel 69 opens outward into the coolant reservoir 96. Fluid coolant can be fed into the retainer coolant channel 92. Therefore, the head channel inlet 69a can be in fluid communication with the retainer channel outlet 92b via the coolant reservoir 96.

[0091] In the assembled position of the rotary milling cutter 20, the milling head 24 and the tool holder 22 are coaxial. In other words, the head center axis B and the holder center axis C coincide with the tool center axis A.

[0092] Positioning the fastening through-hole 67 (at least partially) between the tooth receiving flaps 48 and the threaded hole 88 (also at least partially) between the drive teeth 78 results in a compact joint between the milling head 24 and the tool holder 22. For any given tool diameter, this enables the aforementioned increase in the depth of cut of the groove.

[0093] It should be noted that the milling head 24 shown in the figures does not require additional post-processing to form the keyway (i.e., drive mechanism) adjacent to the centering mechanism, the type of which is disclosed in EP 3153263A1, because the drive mechanism and the centering mechanism are formed together during the formation of the head through recess 44.

[0094] Although the subject matter of this application has been described in detail to a certain extent, it should be understood that various changes and modifications may be made without departing from the spirit or scope of the invention as claimed below.

[0095] For example, multiple cutting edges 32 can be integrally formed with the milling head 24 to have a monolithic (“integral”) construction.

Claims

1. A milling head (24) having a head center axis (B) defining opposite forward directions (DF) and backward directions (DR), and the milling head (24) being rotatable about the head center axis (B) in a rotational direction (R), the milling head (24) comprising: Opposite front surface (26) and rear surface (28) of the head and an outer peripheral surface (30) of the head extending between the front surface (26) and the rear surface (28), the outer peripheral surface (30) of the head extending circumferentially around the central axis (B) of the head; Multiple cutting portions (40) spaced at an angle on the outer periphery; and A head-through recess (44) extends along the head's central axis (B) and opens outwardly to the front surface (26) and the rear surface (28) of the head. The head-through recess (44) is circumferentially defined by the outer peripheral surface (46) of the recess and includes a plurality of radially outwardly extending, angledly spaced toothed receiving flaps (48); wherein: The outer peripheral surface (46) of the recess includes a plurality of driven surfaces (58) and a plurality of radially centered surfaces (62), both of which are located at the plurality of tooth receiving flaps (48) and configured to abut against corresponding surfaces on the tool holder (22). Each driven surface (58) faces a direction opposite to the rotation direction (R), and each radially centered surface (62) faces radially inward. The plurality of radially centering surfaces (62) are radially outwardly positioned from the plurality of driven surfaces (58).

2. The milling head (24) according to claim 1, wherein: The outer peripheral surface (46) of the recess is oriented parallel to the central axis (B) of the head.

3. The milling head (24) according to claim 1 or 2, wherein: The radial centering surface (62) is positioned at the centering surface angle (α) relative to the head central axis (B); and The centering surface angle (α) satisfies the condition: 20°≤α≤40°.

4. The milling head (24) according to any one of claims 1 to 3, wherein: The head-through recess (44) includes a plurality of radially narrowed recesses (50) spaced at an angle, the radially narrowed recesses alternating circumferentially with the toothed receiving flaps (48) along the outer peripheral surface (46) of the recess; and The outer peripheral surface (46) of the recess includes a plurality of recess gap surfaces (66), each recess gap surface (66) being located at a corresponding radially narrowed recess (50) and facing radially inward.

5. The milling head (24) according to any one of claims 1 to 4, wherein: The plurality of radially centering surfaces (62) define an outermost cylinder (OC) of an imaginary recess centered on the head central axis (B).

6. The milling head (24) according to claim 5, wherein: The head through recess (44) includes a plurality of radially narrowed recesses (50) spaced at an angle, which alternate circumferentially with the tooth receiving flap (48) along the outer peripheral surface (46) of the recess. The outer peripheral surface (46) of the recess includes a plurality of recess gap surfaces (66), each recess gap surface (66) being located at a corresponding radially narrowed recess (50) and facing radially inward; The plurality of recessed gap surfaces (66) define an imaginary innermost cylinder (IC) coaxial with the outermost cylinder (OC) of the imaginary recess; The innermost cylinder (IC) of the imaginary concave portion has the innermost cylinder radius (IR); The outermost cylinder (OC) of the imaginary concave portion has a radius (OR) of the outermost cylinder of the concave portion; and The radius (IR) of the innermost cylinder of the recess is less than or equal to 75% of the radius (OR) of the outermost cylinder of the recess.

7. The milling head (24) according to claim 5 or 6, comprising: Multiple angled, spaced-apart fastening through holes (67) that open outward to the front surface (26) and the rear surface (28) of the head and are spaced apart from the through-hole (44) of the head; wherein: Each fastening through hole (67) is located between two angled adjacent tooth receiving flaps (48) of the head through recess (44).

8. The milling head (24) according to claim 7, wherein: The plurality of fastening through holes (67) are located inside the outermost cylinder (OC) of the imaginary recess or intersect with the outermost cylinder (OC) of the imaginary recess.

9. The milling head (24) according to claim 7 or 8, wherein: Each fastening through hole (67) extends along the corresponding fastening through hole axis (F); and The fastening through-hole axis (F) is located inside the outermost cylinder (OC) of the imaginary recess.

10. The milling head (24) according to any one of claims 1 to 9, wherein: The outer peripheral surface (46) of the recess has a recess height (H) as measured in the axial direction; and The plurality of radially centered surfaces (62) and the plurality of driven surfaces (58) extend the entire height (H) of the recess.

11. The milling head (24) according to any one of claims 1 to 10, wherein: The head through recess (44) includes exactly three teeth to receive the leaflets (48).

12. The milling head (24) according to any one of claims 1 to 11, wherein: Each tooth receiving leaflet (48) has exactly one driven surface (58) and exactly one radial centering surface (62) located thereon.

13. The milling head (24) according to any one of claims 1 to 12, wherein, The rear surface (28) includes at least one rearward-facing planar axial support surface (64a, 64b) extending along its entire angular range.

14. The milling head (24) according to any one of claims 1 to 13, wherein: Each tooth receiving leaflet (48) includes a leaflet narrowing portion (LN) and a leaflet widening portion (LW) located radially outside the leaflet narrowing portion (LN); The widening portion (LW) of the leaf has a maximum first width (w1), and the narrowing portion (LN) of the leaf has a maximum second width (w2); and The maximum first width (w1) is greater than the maximum second width (w2).

15. The milling head (24) according to any one of claims 1 to 14, wherein: The head through recess (44) includes a central region (51) connected to the plurality of tooth receiving flaps (48); Each tooth receiving leaflet (48) extends radially from the central region (51) beyond the radial range of the central region (51).

16. A tool holder (22) having a holder central axis (C) defining opposing forward directions (DF) and rearward directions (DR), and the tool holder (22) being rotatable about the holder central axis (C) in the rotational direction (R), the tool holder (22) comprising: The outer peripheral surface (72) of the handle extends circumferentially around the central axis (C) of the retainer; The shank front end surface (70), which is defined by the shank outer peripheral surface (72) located at the front end of the tool holder (22); and A handle protrusion (74) extends from the front end surface (70) of the handle along the central axis (C) of the retainer. The handle protrusion (74) is circumferentially defined by an outer peripheral surface (76) of the protrusion and includes a plurality of radially outwardly extending, angledly spaced centering drive teeth (78); wherein: The outer peripheral surface (76) of the protrusion includes a plurality of driving surfaces (82) and a plurality of radial alignment surfaces (84), the plurality of driving surfaces (82) and the plurality of radial alignment surfaces (84) being located at the plurality of centering drive teeth (78) and configured to abut against corresponding surfaces on the milling head (24), each driving surface (82) facing the rotation direction (R) and each radial alignment surface (84) radially outward; and The plurality of radial alignment surfaces (84) are radially outward from the plurality of drive surfaces (82).

17. The tool holder (22) according to claim 16, wherein: The outer peripheral surface (76) of the protrusion is oriented parallel to the longitudinal axis (C) of the retainer.

18. The tool holder (22) according to claim 16 or 17, wherein: Each radial alignment surface (84) is aligned at an alignment surface angle (β) at the longitudinal axis (C) of the retainer; and The alignment surface angle (β) satisfies the condition: 20°≤β≤40°.

19. The tool holder (22) according to any one of claims 16 to 18, wherein: The shank protrusion (74) includes a plurality of radially narrowed protrusion portions (80) spaced at an angle, the radially narrowed protrusion portions (80) alternating circumferentially with the centering drive teeth (78) along the outer peripheral surface (76) of the protrusion; and The outer peripheral surface (76) of the protrusion includes a plurality of protrusion gap surfaces (86), each protrusion gap surface (86) being located at a corresponding radial protrusion narrowing portion (80) and radially outward.

20. The tool holder (22) according to any one of claims 16 to 19, wherein: The radial alignment surface (84) defines the outermost cylinder (OC') of the imaginary protrusion centered on the central axis (C) of the retainer.

21. The tool holder (22) according to claim 20, wherein: The shank protrusion (74) includes a plurality of radially narrowed protrusion portions (80) spaced at an angle, the radially narrowed protrusion portions (80) alternating circumferentially with the centering drive teeth (78) along the outer peripheral surface (76) of the protrusion; The outer peripheral surface (76) of the protrusion includes a plurality of protrusion gap surfaces (86), each protrusion gap surface (86) being located at a corresponding radially narrowed portion (80) of the protrusion and radially outward; The plurality of protrusion gap surfaces (86) define an innermost cylinder (IC') of the imaginary protrusion that is coaxial with the outermost cylinder (OC') of the imaginary protrusion; The innermost cylinder (IC') of the imaginary protrusion has a radius (IR') of the innermost cylinder of the protrusion; The outermost cylinder (OC') of the imaginary protrusion has a radius (OR') of the outermost cylinder of the protrusion; and The radius (IR') of the innermost cylinder of the protrusion is less than or equal to 75% of the radius (OR') of the outermost cylinder of the protrusion.

22. The tool holder (22) according to claim 20 or 21, comprising: Multiple threaded holes (88) spaced at an angle, opening outward to the front end surface (70) of the shank and spaced apart from the shank protrusion (74); wherein: Each threaded hole (88) is located between two angled adjacent centering drive teeth (78).

23. The tool holder (22) according to claim 22, wherein: The plurality of threaded holes (88) are located inside the outermost cylinder (OC') of the imaginary protrusion or intersect with the outermost cylinder (OC') of the imaginary protrusion.

24. The tool holder (22) according to claim 22 or 23, wherein: Each threaded hole (88) extends along the corresponding threaded hole axis (G); and The axis (G) of the threaded hole is located inside the outermost cylinder (OC') of the imaginary protrusion.

25. The tool holder (22) according to any one of claims 16 to 24, wherein: The outer peripheral surface (76) of the protrusion has a protrusion height (H′) as measured in the axial direction; and The plurality of radial alignment surfaces (84) and the plurality of drive surfaces (82) extend the entire height (H') of the protrusion.

26. The tool holder (22) according to any one of claims 16 to 25, wherein: The shank protrusion (74) includes exactly three centering drive teeth (78).

27. The tool holder (22) according to any one of claims 16 to 26, wherein: Each centering drive tooth (78) has exactly one drive surface (82) and exactly one radial alignment surface (84) located thereon.

28. The tool holder (22) according to any one of claims 16 to 27, wherein: The front end surface (70) of the handle includes at least one forward-facing planar axial support surface (90a, 90b) extending along its entire angular range.

29. A rotary milling cutter (20), comprising: The milling head (24) according to any one of claims 1 to 15; as well as The tool holder (22) according to any one of claims 16 to 28; and in: The milling head (24) can be releasably attached to the tool holder (22); The handle protrusion (74) is located in the head through recess (44); The plurality of radial centering surfaces (62) directly abut against the plurality of radial alignment surfaces (84) of the connecting portion (74); and The plurality of driven surfaces (58) directly abut against the plurality of driving surfaces (82).

30. The rotary milling cutter (20) according to claim 29, wherein: The rear surface (28) includes at least one rearward-facing axial planar support surface (64a, 64b) extending along its entire angular range. The front end surface (70) of the handle includes at least one forward-facing planar axial support surface (90a, 90b) extending along its entire angular range; and The at least one axial support surface (64a, 64b) abuts against the at least one axial support surface (90a, 90b).

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