Milling head with through-holes having a centering surface and a drive surface in the tooth receiving lobe, tool holder, and rotary milling tool

Abstract

A rotary milling tool comprises a tool holder and a milling head releasably mounted to the tool holder. The milling head has through-recesses opening on the front and rear surfaces of the head. These recesses include a plurality of radially extending tooth-receiving lobes. The tool holder has a protrusion containing a plurality of radially extending teeth. When assembled, these teeth are positioned within the tooth-receiving lobes, providing centering and torque transmission capabilities.

Description

Technical Field

[0001]

[0001] The subject matter of the present application relates to a milling head having a plurality of cutting portions arranged on the outer periphery, and in particular, to a rotary milling tool having a milling head with a through hole. The through hole has a plurality of driven surfaces for torque transmitted from a tool holder and a plurality of radial centering surfaces for radially aligning the milling head with respect to the tool holder.

Background Art

[0002]

[0002] A rotary milling tool may include a milling head releasably clamped to a tool holder by at least one fastening member (e.g., a retaining screw). The milling head may have a plurality of cutting portions arranged on the outer periphery. The milling head may have a through hole for engaging a convex portion for providing radial centering of the milling head with respect to the tool holder. Typically, this through hole is cylindrical. The milling head may have a keyway extending radially outward from the through hole for receiving a key for providing torque transmission from the tool holder to the milling head.

[0003]

[0003] Such various cutting tools and milling heads are disclosed in JP 2021-094680, German Utility Model No. 202017105606, and US Patent No. 7,153,068.

[0004]

[0004] The object of the subject matter of the present application is to provide an improved and compact engagement between the milling head and the tool holder.

Summary of the Invention

[0005]

[0005] According to a first aspect of the subject matter of the present application, a milling head having a head central axis (B) is provided. The head central axis defines a forward direction and a rearward direction which are opposite directions, and the milling head is rotatable in a rotational direction (R) about the head central axis. The milling head Opposing head front and head rear surfaces, and a head circumferential surface extending between the head front and head rear surfaces and extending circumferentially around the head central axis, Multiple cutting sections are arranged on the outer circumference at angular intervals, A head through recess extending along the head's central axis and opening to the front and rear surfaces of the head, wherein the head through recess comprises a plurality of tooth-receiving lobes whose circumferential boundary is defined by the circumferential surface of the recess and which are arranged at angular intervals, and the plurality of tooth-receiving lobes extend radially outward, The recessed circumferential surface comprises a plurality of driven surfaces and a plurality of radial centering surfaces, all of which are located on a plurality of tooth receiving lobes and are configured to contact corresponding surfaces on the tool holder, each driven surface facing in the rotational direction, and each radial centering surface facing radially inward. Multiple radial centering surfaces are located radially outward from multiple driven surfaces.

[0006]

[0006] According to a second aspect of the subject matter of this application, a tool holder is provided, the tool holder having a holder central axis defining a forward and backward direction which are opposite directions, the tool holder being rotatable in a rotational direction about the holder central axis, the tool holder The shank surface extends circumferentially around the holder's central axis, The shank front end surface, which is bounded by the shank circumferential surface located at the front end of the tool holder, A shank projection extending from the front end face of the shank along the holder's central axis, comprising a shank projection whose circumferential boundary is defined by the circumferential surface of the projection and which comprises a plurality of centering drive teeth arranged at angular intervals, the plurality of centering drive teeth extending radially outward, and The circumferential surface of the convex portion comprises multiple drive surfaces and multiple radial alignment surfaces, all of which are located on multiple centering drive teeth and are configured to contact corresponding surfaces on the milling head, with each drive surface facing in the rotational direction and each radial alignment surface facing radially outward. Multiple radial alignment surfaces are located radially outward from multiple drive surfaces.

[0007]

[0007] According to a third aspect of the subject matter of this application, a rotary milling tool is provided, which rotary milling tool is, The above type of milling head and The tool holder of the above type is provided, The milling head is releasably mounted on the tool holder. The shank protrusion is located within the recess that penetrates the head. Multiple radial centering surfaces directly contact multiple radial alignment surfaces of the shank protrusion. Multiple driven surfaces come into direct contact with multiple driving surfaces.

[0008]

[0008] The above is a summary, and the features described herein may be applicable to any combination of the subject matter of this application, and it is understood that, for example, any of the following features may be applicable to a milling head, a tool holder, or a rotary milling tool.

[0009]

[0009] The circumferential surface of the recess can be oriented parallel to the head's central axis.

[0010]

[0010] The radial centering surface forms a centering surface angle with respect to the head's central axis. This centering surface angle may be 20° or more and 40° or less.

[0011]

[0011] The head through recess may comprise a plurality of radially narrow recess portions arranged at angular intervals, and the plurality of radially narrow recess portions are arranged alternately with tooth receiving lobes along the circumferential surface of the recess. The circumferential surface of the recess may comprise a plurality of recess relief surfaces, each recess relief surface located in its respective radially narrow recess and facing radially inward.

[0012]

[0012] Multiple recessed relief surfaces can be shaped into a convex shape.

[0013]

[0013] The plurality of radial centering surfaces 62 may be shaped into a concave shape.

[0014]

[0014] The plurality of radial centering surfaces may define a virtual concave outer cylinder centered with respect to the head central axis.

[0015]

[0015] The plurality of radial centering surfaces may be on the inner surface of the virtual concave outer cylinder.

[0016]

[0016] The plurality of recess relief surfaces may define a virtual concave inner cylinder coaxial with the virtual concave outer cylinder. The virtual concave inner cylinder has a concave inner cylinder radius. The virtual concave outer cylinder has a concave outer cylinder radius. The concave inner cylinder radius may be 75% or less of the concave outer cylinder radius.

[0017]

[0017] The milling head may include a plurality of fastening through holes arranged at angular intervals, the plurality of fastening through holes opening on the front surface and the rear surface of the head and being arranged at intervals from the head through recess. Each fastening through hole may be located between two angularly adjacent tooth receiving lobes of the head through recess.

[0018]

[0018] The plurality of fastening through holes may be located inside the virtual concave outer cylinder or may intersect the virtual concave outer cylinder.

[0019]

[0019] Each fastening through hole extends along its respective fastening through hole axis. The fastening through hole axis may be located inside the virtual concave outer cylinder.

[0020]

[0020] The recess peripheral surface has a recess height measured in the axial direction. The plurality of radial centering surfaces and the plurality of driven surfaces may extend over the entire recess height.

[0021]

[0021] The head through recess may include exactly three tooth receiving lobes.

[0022]

[0022] All tooth receiving lobes can have exactly one driven surface and exactly one radial centering surface located thereon.

[0023]

[0023] The milling head may include a plurality of chip grooves arranged at angular intervals, and the plurality of chip grooves are alternately arranged in the circumferential direction with a plurality of cutting portions along the head circumferential surface, and each chip groove opens to at least one of the head front surface and the head rear surface. Each cutting portion may include an insert receiving pocket.

[0024]

[0024] The head rear surface may include at least one planar axial bearing surface facing rearward, and the axial bearing surface extends along the entire angular range of the head rear surface.

[0025]

[0025] Each tooth receiving lobe includes a lobe width narrow portion and a lobe width wide portion located radially outside the lobe width narrow portion, the lobe width wide portion has a first maximum width, and the lobe width narrow portion has a second maximum width. The first maximum width may be greater than the second maximum width.

[0026]

[0026] The head through recess may include a central region connecting to a plurality of tooth receiving lobes. The radial length of each tooth receiving lobe from the central region may exceed the radial range of the central region.

[0027]

[0027] The convex peripheral surface may be oriented parallel to the holder longitudinal axis.

[0028]

[0028] Each radial alignment surface may form an alignment surface angle with the holder longitudinal axis. The alignment surface angle may be 20° or more and 40° or less.

[0029]

[0029] The shank convex portion may include a plurality of radially convex portion width narrow portions arranged at angular intervals, and the plurality of radially convex portion width narrow portions are alternately arranged in the circumferential direction with centering drive teeth along the convex peripheral surface. The convex peripheral surface may include a plurality of convex relief surfaces, and each convex relief surface is located at each radially convex portion width narrow portion and faces radially outward.

[0030]

[0030] Multiple convex relief surfaces can be shaped into a concave form.

[0031]

[0031] The radial alignment surface can be shaped into a convex shape.

[0032]

[0032] The radial alignment surface can define the outermost cylinder of the virtual protrusion that is centered on the holder's central axis.

[0033]

[0033] The radial alignment surface may be on the outer surface of the outermost cylinder of the virtual convex portion.

[0034]

[0034] Multiple relief surfaces of the convex portion can define a virtual innermost convex portion that is coaxial with the virtual outermost convex portion cylinder. The virtual innermost convex portion cylinder has a convex innermost cylinder radius (IR'). The virtual outermost convex portion cylinder has a convex outermost cylinder radius. The convex innermost cylinder radius may be 75% or less of the convex outermost cylinder radius.

[0035]

[0035] The tool holder may have a plurality of screw holes arranged at an angular interval, the plurality of screw holes opening on the front end face of the shank and spaced apart from the shank protrusion. Each screw hole may be located between two angularly adjacent centering drive teeth.

[0036]

[0036] The multiple screw holes may be located inside the outermost cylinder of the virtual protrusion, or they may intersect with the outermost cylinder of the virtual protrusion.

[0037]

[0037] Each screw hole extends along its respective screw hole axis. The screw hole axis may be located inside the outermost cylinder of the virtual protrusion.

[0038]

[0038] The circumferential surface of the protrusion has a protrusion height measured in the axial direction. Multiple radial alignment surfaces and multiple drive surfaces may extend across the entire protrusion height.

[0039]

[0039] The shank projection may have exactly three centering drive teeth.

[0040]

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

[0041]

[0041] The front end face of the shank may have at least one planar axial support surface facing forward, the axial support surface extending along the entire angular range of the front end face of the shank.

[0042]

[0042] At least one axial bearing surface may contact at least one axial support surface.

[0043]

[0043] The milling head can be releasably clamped to the tool holder by a plurality of threaded fastening members, each threaded fastening member located within its own fastening through hole and screwed into its own threaded hole. [Brief explanation of the drawing]

[0044]

[0044] For a deeper understanding of this application and to show how this application is actually implemented, refer to the attached drawings below.

[0045] [Figure 1]

[0045] This is a perspective view of the rotary milling tool according to the present application. [Figure 2]

[0046] Figure 1 is an exploded perspective view of a rotary milling tool. [Figure 3]

[0047] Figure 1 is a front view of the milling head, showing five hidden head coolant channels. [Figure 4]

[0048] Figure 3 is a rear view of the milling head, showing five hidden head coolant channels. [Figure 4a]

[0049] This is a detailed view of Figure 4. [Figure 5]

[0050] Figure 3 is a side view of the milling head. [Figure 6]

[0051] This is a perspective view showing the front end of the tool holder according to this application. [Figure 7]

[0052] Figure 6 is a front view of the tool holder. [Figure 8]

[0053] Figure 6 is a side view showing the front end of the tool holder, and shows three hidden holder coolant channels opening into hidden radial relief recesses. [Figure 9]

[0054] Figure 1 is a front view of the rotary milling tool. [Figure 10]

[0055] Figure 1 is a side view showing the front end of the rotary milling tool. [Figure 11]

[0056] Figure 9 is an axial cross-sectional view of the rotary milling tool along line XX. [Figure 12]

[0057] Figure 10 is a radial cross-sectional view of a rotary milling tool along line YY. [Figure 13]

[0058] Figure 10 is a radial cross-sectional view of a rotary milling tool along line ZZ.

[0046]

[0059] For the purpose of simplifying and clarifying explanations, it should be understood that elements shown in the drawings are not necessarily drawn to scale. For example, the dimensions of some elements may be exaggerated compared to others for clarity, or several physical components may be contained within a single functional block or element. Furthermore, reference numbers may be repeated across multiple drawings to indicate corresponding or similar elements, where necessary. [Modes for carrying out the invention]

[0047]

[0060] In the following description, various aspects of the subject matter of this application are described below. For illustrative purposes, specific configurations and details are described with sufficient detail to provide a complete understanding of the subject matter of this application. However, as will be apparent to those skilled in the art, the subject matter of this application can be carried out without the specific configurations and details presented herein.

[0048]

[0061] First, looking at Figures 1 and 2, a rotary milling tool 20 is illustrated, which represents one aspect of the present application. In the non-limiting examples shown in the figures, the rotary milling tool 20 can form a slitting saw suitable for slitting operations. The rotary milling tool 20 has a tool central axis A. The rotary milling tool 20 has a tool holder 22, which is typically made of steel. The rotary milling tool 20 has a milling head 24, which is typically made of steel. The milling head 24 is releasably mounted to the tool holder 22.

[0049]

[0062] Next, referring to Figures 3-5, another aspect of the subject matter of this application is shown with respect to the milling head 24. The milling head 24 has a head central axis B. The head central axis B is in the opposite direction, forward D F and backward direction D R The following is defined: The head's central axis B forms a rotation axis, and the milling head 24 is rotatable around this rotation axis in the rotation direction R. Here, the rotation direction R is the cutting direction.

[0050]

[0063] In the following description of the milling head 24, naturally, when the terms "forward" and "backward" are used, throughout the specification and claims, they refer to the direction to the left (or backward) of the head's central axis B in Figure 5, respectively. R ) and to the right (or forward D) F This refers to the relative position in ). Furthermore, unless otherwise specified, terms such as "axial direction" and "radial direction" refer to the direction with respect to the head's central axis B.

[0051]

[0064] The blank for producing the milling head 24 may be manufactured additively. The term “additive manufacturing” as used throughout this specification and claims refers to a type of component formed using one or more additive manufacturing processes used to produce a three-dimensional object in which layers of material are formed. 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.

[0052]

[0065] As shown in Figures 3-5, the milling head 24 includes opposing head fronts 26 and 28, and a head circumferential surface 30 extending between them. The head front 26 is axially forward of the head rear surface 28. The head circumferential surface 30 extends circumferentially about the head central axis B. Generally, the head circumferential surface 30 faces radially outward. According to some embodiments of the subject matter of this application, as shown in Figure 6, the milling head 24 may be shorter in the axial direction than in the radial direction. The head fronts 26 and 28 may be parallel to each other and oriented perpendicular to the head central axis B. The milling head 24 may have a disc-shaped basic form defined by the head fronts 26 and 28 and the head circumferential surface 30.

[0053]

[0066] Referring to Figures 3 and 4, the milling head 24 includes a plurality of cutting portions 40 arranged at angular intervals, the cutting portions 40 extending radially outward. According to some embodiments of the subject matter of this application, each cutting portion 40 may include an insert receiving pocket 108 for seating a cutting insert 110. The cutting insert 110 includes a cutting edge 32. The milling head 24 may include a plurality of chip grooves 42 arranged at angular intervals for chip evacuation. The chip grooves 42 are recessed (radially inward) from the head circumferential surface 30 and are arranged circumferentially alternately with the plurality of cutting portions 40 along the head circumferential surface 30. According to some embodiments of the subject matter of this application, each chip groove 42 may open to both the head front 26 and the head rear 28.

[0054]

[0067] The milling head 24 includes a head through recess 44 that opens into the head front surface 26 and the head rear surface 28. The head through recess 44 is centrally located because it extends along the head central axis B. In other words, the head central axis B passes through the head through recess 44. The head through recess 44 is bounded circumferentially by a recess surface 46. The recess surface 46 extends circumferentially about the head central axis B. Generally, the recess surface 46 faces radially inward. According to some embodiments of the subject matter of this application, the recess surface 46 may be oriented parallel to the head central axis B. Referring to Figure 5, the recess surface 46 has a recess height H measured axially (i.e., along the head central axis B). The recess height H may be constant along the recess surface 46. The recess height H may be the same as the axial thickness of the milling head 24.

[0055]

[0068] Referring to Figures 3, 4, and 4a, the milling head 24 includes a plurality of drive projections 60 arranged at angular intervals, which extend radially inward into the head through-recess 44. Therefore, the head through-recess 44 is non-cylindrical. Specifically, the head through-recess 44 has a central region 51 that connects to a plurality of angle-spaced tooth-receiving lobes 48. Each drive projection 60 is located between two adjacent tooth-receiving lobes 48. The tooth-receiving lobes 48 extend radially outward. Each tooth-receiving lobe 48 includes a narrow lobe portion LN and a wide lobe portion LW located radially outward of the narrow lobe portion LN. Therefore, each tooth-receiving lobe 48 may have a non-rectangular shape, such as a pear shape. Due to the presence of the drive projections 60, the head through-recess 44 includes a plurality of radially narrow recess portions 50 arranged at angular intervals. The tooth-receiving lobes 48 are designed to receive drive teeth, as will be described later in this specification. The multiple radial recessed narrow sections 50 are arranged alternately with the tooth-receiving lobes 48 in the circumferential direction along the recessed circumferential surface 46. The recessed circumferential surface 46 is such that the distance from the head central axis B in the tooth-receiving lobes 48 is greater than the distance from the head central axis B in the radial recessed narrow sections 50. In this non-limiting example shown in the drawings, the milling head 24 includes exactly three drive projections 60 (although other numbers of drive projections 60 are also conceivable). Thus, the head through recess 44 includes exactly three tooth-receiving lobes 48 and exactly three radial recessed narrow sections 50. The multiple drive projections 60 and the multiple tooth-receiving lobes 48 may each be identical.

[0056]

[0069] The recessed circumferential surface 46 includes a plurality of driven surfaces 58, each driven surface 58 associated with its respective tooth-receiving lobe 48. The plurality of driven surfaces 58 are configured for torque transmission by directly contacting corresponding surfaces on the tool holder 22. The plurality of driven surfaces 58 may be planar. Each driven surface 58 faces the rotational direction R. Each driven surface 58 is located on its respective tooth-receiving lobe 48. Preferably, all tooth-receiving lobes 48 have exactly one driven surface 58 located thereon.

[0057]

[0070] The recessed circumferential surface 46 includes a plurality of radial centering surfaces 62, each radial centering surface 62 associated with its respective tooth-receiving lobe 48. The plurality of radial centering surfaces 62 are designed to be coaxial when the two parts are assembled by centering the milling head 24 relative to the tool holder 22. Each radial centering surface 62 faces radially inward. Each radial centering surface 62 is located on its respective tooth-receiving lobe 48. Preferably, all tooth-receiving lobes 48 have exactly one radial centering surface 62 located on it.

[0058]

[0071] The multiple radial centering surfaces 62 are shaped concave. The term “shaped convex / concave” as used herein and in the claims is understood to include a surface that is continuously (i.e., smoothly) curved in a convex / concave shape, or a surface consisting of multiple linear subsurfaces that provide a surface having a convex / concave shape. The multiple radial centering surfaces 62 can preferably be continuously curved concave.

[0059]

[0072] Referring to Figure 4a, according to some embodiments of the subject matter of this application, a plurality of radial centering surfaces 62 may define a virtual recess outermost cylinder OC centered on the head central axis B. The virtual recess outermost cylinder OC may be an inscribed cylinder. The plurality of radial centering surfaces 62 may be on the inner surface of the virtual recess outermost cylinder OC. The virtual recess outermost cylinder OC defines the boundaries of a plurality of tooth receiving lobes 48 in the radially outward direction. Similarly, the virtual recess outermost cylinder OC may define the boundaries of a plurality of protrusions 60 in the radially outward direction. The virtual recess outermost cylinder OC has a recess outermost cylinder radius OR.

[0060]

[0073] According to some embodiments of the subject matter of this application, the radial centering surface 62 can form a centering surface angle α with respect to 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°.

[0061]

[0074] In each tooth receiving lobe 48, the wider lobe portion LW is wider in the circumferential direction than the narrower lobe portion LN. As can be seen from Figure 4a, the wider lobe portion LW has a first maximum width w1, while the narrower lobe portion LN has a second maximum 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 up to 80% longer than w2). Here, the lobe widths w1 and w2 are shown to be measured in a direction perpendicular to a radial line R1 that intersects the head central axis B and bisects the centering angle α, and the lobe widths w1 and w2 represent the circumferential width in the wider lobe portion LW and the narrower lobe portion LN.

[0062]

[0075] The multiple radial centering surfaces 62 are located radially outward from the multiple driven surfaces 58. According to some embodiments of the subject matter of this application, the multiple radial centering surfaces 62 and the multiple driven surfaces 58 may extend across the total height H of the recess.

[0063]

[0076] According to some embodiments of the subject matter of this application, the recessed circumferential surface 46 may include a plurality of recessed relief surfaces 66. Each recessed relief surface 66 may be located in the respective radially narrowed portion 50 of the recess. Each recessed relief surface 66 faces radially inward. The plurality of recessed relief surfaces 66 may be shaped convexly. Preferably, the plurality of recessed relief surfaces 66 are continuously curved in a convex manner. More preferably, the plurality of recessed relief surfaces 66 may be located on the inner surfaces of separate virtual cylinders (not shown) that are not centered with respect to the head central axis B.

[0064]

[0077] Referring to Figure 4a, according to some embodiments of the subject matter of this application, a plurality of recess relief surfaces 66 may define a virtual recess innermost cylinder IC coaxial with the virtual recess outermost cylinder OC. The virtual recess innermost cylinder IC may be an inscribed cylinder. The plurality of recess relief surfaces 66 may contact the virtual recess innermost cylinder IC (but not extend across it). The virtual recess innermost cylinder IC has a recess innermost cylinder radius IR. The recess innermost cylinder radius IR may be 75% or less of the recess outermost cylinder radius OR. Preferably, the recess innermost cylinder radius IR may be 50% or less of the recess outermost cylinder radius OR. The virtual recess innermost cylinder IC has a recess innermost cylinder radius IR that can define the range of the central region 51 of the head through recess 44. A plurality of drive protrusions 60 may terminate radially inward in the central region 51. Since the outermost cylindrical radius OR of the recess is greater than the innermost cylindrical radius IR of the recess, the radial length of each tooth receiving lobe 48 (from the central region 51) is greater than the radial range of the central region 51 itself.

[0065]

[0078] According to some embodiments of the subject matter of this application, the milling head 24 may include a plurality of fastening through-holes 67 opening in 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., set screws) for attaching the milling head 24 to the tool holder 22. The number of fastening through-holes 67 is preferably equal to the number of drive protrusions 60.

[0066]

[0079] According to some embodiments of the subject matter of this application, the multiple fastening through holes 67 may be arranged at angular intervals with respect to the head central axis B. The multiple fastening through holes 67 may be arranged away from the head through recess 44.

[0067]

[0080] Each fastening through-hole 67 extends along its respective 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 circumferential surface 67a extending about the fastening through-hole axis F. Each fastening through-hole 67 may be rotationally symmetric about the fastening through-hole axis F. In particular, the fastening hole circumferential surface 67a may be cylindrical. Viewed from a direction along the fastening through-hole axis F, the fastening hole circumferential surface 67a may define the perforated portion of the through-fastening through-hole 67. The fastening through-hole 67 may open to the head front surface 26 through a chamfered portion for accommodating the screw head (see comparison of Figures 3 and 4).

[0068]

[0081] Referring to Figure 4a, each fastening through-hole 67 may be located between two angularly adjacent tooth-receiving lobes 48 (of the head through-recess 44). Multiple fastening through-holes 67 may be located inside the outermost cylinder OC of the virtual recess, or they may intersect with the outermost cylinder OC of the virtual recess. In other words, multiple fastening through-holes 67 may not be located outside the outermost cylinder OC of the virtual recess. The fastening through-hole axis F may be located inside the outermost cylinder OC of the virtual recess. Most of the circumferential surface 67a of each fastening through-hole 67 may be located on their respective drive protrusions 60.

[0069]

[0082] As best seen in Figure 11, according to some embodiments of the subject matter of this application, the head rear surface 28 may include at least one rearward-facing axial bearing surface 64a, 64b. The at least one axial bearing 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 bearing surface 64a, 64b may be planar and may be oriented perpendicular to the head central axis B. The at least one axial bearing surface 64a, 64b may extend along the entire angular range (i.e., 360°) of the head rear surface 28. In this non-limiting example shown in the drawings, the head rear surface 28 may include first and second axial bearing surfaces 64a, 64b. The first and second axial bearing surfaces 64a, 64b are spaced radially apart, with the first axial bearing surface 64a located radially outward of the second axial bearing surface 64b. The first and second axial bearing surfaces 64a and 64b may be on the same plane as each other.

[0070]

[0083] Referring to Figures 3 and 4, according to some embodiments of the subject matter of this application, the milling head 24 may include a plurality of head coolant channels 69 (the outlines of these channels are shown by dashed lines) for guiding coolant into the cutting area. Each head coolant channel 69 has a head channel inlet 69a which may be located on the rear surface 28 of the head and a head channel outlet 69b which may be located on the circumferential surface 30 of the head. In this non-limiting example shown in the drawings, each head channel outlet 69b is located in the respective tip groove 42.

[0071]

[0084] Next, referring to Figures 6-8, a tool holder 22 illustrating a second aspect of the present invention is shown. The tool holder 22 has a holder central axis C. The tool holder 22 can be extended along the holder central axis C. The holder central axis C is in the forward direction D F and backward direction D R It extends to the center axis C of the holder, which forms a rotation axis, and the tool holder 22 is rotatable in the rotational direction R around this rotation axis.

[0072]

[0085] Naturally, in the following description of the tool holder 22, the terms "front" and "rear" refer to their relative positions in the vertical direction of the holder's central axis C in Figure 8, respectively, throughout the specification and claims. Furthermore, the terms "axial" and "radial" refer to directions relative to the holder's central axis C, unless otherwise specified.

[0073]

[0086] The tool holder 22 has a shank circumferential surface 72 that extends circumferentially with respect to the holder's central axis C. The tool holder includes a shank front end surface 70 bounded by the shank circumferential surface 72. The shank circumferential surface 72 may be cylindrical and can define the shank diameter D.

[0074]

[0087] Referring to Figure 6, the tool holder 22 includes a shank projection 74 that protrudes from the shank front end face 70 along the holder central axis C. The shank projection 74 is circumferentially bounded by a projection circumferential surface 76. The projection circumferential surface 76 extends circumferentially with respect to the holder central axis C. Generally, the projection circumferential surface 76 faces radially outward. According to some embodiments of the subject matter of this application, the projection circumferential surface 76 may be oriented parallel to the holder longitudinal axis C. The projection circumferential surface 76 may have a projection height H' measured axially (i.e., along the holder central axis C). The projection height H may be constant along the projection circumferential surface 76.

[0075]

[0088] Referring to Figure 7, the shank projection 74 includes a plurality of centering drive teeth 78 arranged at angular intervals and extending radially outward. The shank projection 74 also includes a plurality of radial projection narrows 80 arranged at angular intervals, which alternate circumferentially with the centering drive teeth 78 along the projection circumferential surface 76. The projection circumferential surface 76 is further from the holder central axis C than the radial projection narrows 80 on the centering drive teeth 78. In this non-limiting example shown in the drawing, the shank projection 74 includes exactly three centering drive teeth 78 and exactly three radial projection narrows 80. Adjacent pairs of centering drive teeth 78 are spaced apart by an intertooth gap 79. The plurality of centering drive teeth 78 may be identical.

[0076]

[0089] The convex circumferential surface 76 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 central axis C, torque is transmitted to the milling head 24 via the drive surfaces 82. The plurality of drive surfaces may be planar. Each drive surface 82 faces the rotational direction R. Each drive surface 82 is located on its respective centering drive tooth 78. Preferably, all drive teeth 78 have exactly one driven surface 82 located on it.

[0077]

[0090] The convex circumferential surface 76 includes a plurality of radial alignment surfaces 84 for direct contact with a plurality of radial centering surfaces 62. Each radial alignment surface 84 faces radially outward. Each radial alignment surface 84 is located on its respective centering drive tooth 78. Preferably, all centering drive teeth 78 have exactly one radial alignment surface 84 located on them.

[0078]

[0091] Multiple radial alignment surfaces 84 can be shaped into a convex form. Preferably, the multiple radial alignment surfaces 84 can be continuously curved in a convex shape.

[0079]

[0092] Referring to Figure 7, according to some embodiments of the subject matter of this application, the radial alignment surface 84 may define a virtual outermost convex cylinder OC' centered on the holder central axis C. The virtual outermost convex cylinder OC' may be an inscribed cylinder. Multiple radial alignment surfaces 84 may be on the outer surface of the virtual outermost convex cylinder OC'. The virtual outermost convex cylinder OC' has a convex outermost cylinder radius OR'. The virtual outermost convex cylinder OC' defines the boundary of each tooth gap 79 in the radially outward direction.

[0080]

[0093] According to some embodiments of the subject matter of this application, each radial alignment surface 84 can form an alignment surface angle β with respect to the holder longitudinal axis C. 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°.

[0081]

[0094] The multiple radial alignment surfaces 84 are located radially outward from the 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 total height H' of the protrusion.

[0082]

[0095] According to some embodiments of the subject matter of this application, the convex circumferential surface 76 may include a plurality of convex relief surfaces 86. Each convex relief surface 86 may be located in the respective radially narrow portion 80 of the convex. Each convex relief surface 86 may face radially outward. The plurality of convex relief surfaces 86 may be shaped concave. Preferably, the plurality of convex relief surfaces 86 may be continuously curved concave.

[0083]

[0096] Referring again to Figure 7, according to some embodiments of the subject matter of this application, a plurality of convex relief surfaces 86 may define a virtual convex innermost cylinder IC' coaxial with the virtual convex outermost cylinder OC'. The virtual convex innermost cylinder IC' may be an inscribed cylinder. The plurality of convex relief surfaces 86 may contact the virtual convex innermost cylinder IC' (but not extend across the virtual convex innermost cylinder IC'). The virtual convex outermost cylinder OC' defines the boundary of a plurality of centering drive teeth 78 in the radially inward direction. The virtual convex innermost cylinder IC' has a convex innermost cylinder radius IR'. The convex innermost cylinder radius IR' may be 75% or less of the convex outermost cylinder radius OR'. Preferably, the convex innermost cylinder radius IR' may be 50% or less of the convex outermost cylinder radius OR'.

[0084]

[0097] According to some embodiments of the subject matter of this application, the tool holder 22 may include a plurality of screw holes 88 opening in the shank front end face 70. The screw holes 88 are for screwing in fastening members 68, as will be described later. The number of screw holes 88 is preferably the same as the number of centering drive teeth 78.

[0085]

[0098] Each screw hole 88 extends along its respective screw hole axis G. According to some embodiments of the subject matter of this application, the multiple screw holes 88 may be arranged at angular intervals with respect to the holder central axis C. The multiple screw holes 88 may be arranged away from the shank projection 74.

[0086]

[0099] Referring to Figure 7, each screw hole 88 may be located between two angularly adjacent centering drive teeth 78. Multiple screw holes 88 may be located inside the outermost cylinder OC' of the virtual convexity, or they may intersect with the outermost cylinder OC' of the virtual convexity. The screw hole axis G may be located inside the outermost cylinder OC' of the virtual convexity. Most of each screw hole 88 may be located within their respective intertooth gaps 79. Advantageously, by positioning the multiple screw holes 88 closer to the holder central axis C (for example, so that they are at least partially located within the intertooth gaps 79), the shank diameter D can be reduced. Thus, the depth of cut of the slot can be increased for any particular tool diameter.

[0087]

[0100] As can be best seen in Figure 11, according to some embodiments of the subject matter of this application, the shank front end face 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 may be oriented perpendicular to the holder 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 face 70. In this non-limiting example shown in the drawings, the shank front end face 70 may include first and second axial support surfaces 90a, 90b. The first and second axial support surfaces 90a, 90b may be radially spaced apart by a radial relief recess 94 recessed within the shank front end face 70, where the first axial support surface 90a is located radially outward of the second axial support surface 90b. The radial relief recess 94 may extend along the entire angular range (i.e., 360°) of the shank front end face 70. The first and second axial support surfaces 90a and 90b may be coplanar with each other. Multiple screw holes 88 may open within the radial relief recess 94. The second axial support surface 90b may surround the shank protrusion 74.

[0088] [000101] Referring 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 supplying coolant to 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 face 70. In particular, the holder coolant channel outlet 92b may be located within a radial relief recess 94.

[0089] [000102] Referring to Figures 1 and 2, the milling head 24 is releasably clamped to the tool holder 22 by a plurality of fastening members 68 to form the 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 set screw having a single monolithic structure with a male thread 104. That is, each fastening member 68 is "screwed in".

[0090] [000103] Next, refer to Figures 9-13. In the assembled position of the rotary milling tool 20, the shank projection 74 is located within the head through recess 44. Each screwed fastener 68 is located within its respective fastening through hole 67 and is screwed into its respective screw hole 88. The centering drive teeth 78 are located within the tooth receiving lobes 48 of the head through recess 44 of the milling head. Multiple driven surfaces 58 are in direct contact with multiple drive surfaces 82. Multiple radial centering surfaces 62 are in direct contact with multiple radial alignment surfaces 84. According to some embodiments of the subject matter of this application, at least one axial bearing surface 64a, 64b may be in contact with at least one axial support surface 90a, 90b. Multiple recess relief surfaces 66 do not have to be in contact with multiple projection relief surfaces 86.

[0091] [000104] Referring to Figures 11 and 12, according to some embodiments of the subject matter of this application, in the assembled position of the rotary milling tool 20, the radial relief recess 94 is sealed by a portion of the head rear surface 28, thereby forming a coolant reservoir 96. In the non-limiting examples shown in the drawings, this seal is formed by the contact of the first and second axial bearing surfaces 64a, 64b with the first and second axial support surfaces 90a, 90b, respectively. The head channel inlet 69a may be located on the head rear surface 28 such that the head coolant channel 69 opens into the coolant reservoir 96. Fluid coolant can be supplied to the holder coolant channel 92. Thus, the head channel inlet 69a can be in fluid communication with the holder channel outlet 92b via the coolant reservoir 96.

[0092] [000105] In the assembled position of the rotary milling tool 20, the milling head 24 and the tool holder 22 are coaxial. In other words, the head central axis B and the holder central axis C are in the same position as the tool central axis A.

[0093] [000106] By positioning the fastening through-hole 67 between the tooth receiving lobes 48 (at least partially) and the screw hole 88 between the drive teeth 78 (likewise at least partially), a compact connection is made between the milling head 24 and the tool holder 22. This allows for a larger cutting depth of the slot for any particular tool diameter, as described above.

[0094] [000107] The illustrated milling head 24 does not require any additional post-processing to form a keyway (i.e., a drive mechanism) adjacent to a centering mechanism of the type disclosed in European Patent Application Publication No. 3153263A1. This is because the drive mechanism and the centering mechanism are formed together during the formation of the head through recess 44.

[0095] [000108] The subject matter of this application has been described with a certain degree of specificity, but naturally, a variety of changes and modifications can be made without departing from the spirit or scope of the invention as described in the following claims.

[0096] [000109] For example, the multiple cutting edges 32 may be formed integrally with the milling head 24, and together with the milling head 24, they may have a single, integrated (monolithic) structure.

Claims

1. A milling head (24) having a head central axis (B), wherein the head central axis (B) is in the opposite direction, forward and backward (D Ｆ , D Ｒ The milling head (24) is defined to be rotatable in the rotational direction (R) about the head central axis (B), and the milling head (24) is Opposing head front and head rear surfaces (26, 28), and a head circumferential surface (30) extending between the head front and the head rear surfaces (26, 28) and extending circumferentially with respect to the head central axis (B), Multiple cutting portions (40) are arranged on the outer circumference at angular intervals, A head through recess (44) extending along the head central axis (B) and opening to the head front and head rear surfaces (26, 28), wherein the head through recess (44) has a boundary defined in the circumferential direction by the recess circumferential surface (46) and comprises a plurality of tooth receiving lobes (48) arranged at angular intervals, the plurality of tooth receiving lobes (48) extending radially outward, The recessed circumferential surface (46) comprises a plurality of driven surfaces (58) and a plurality of radial centering surfaces (62), all of which are located on the plurality of tooth receiving lobes (48) and are configured to abut the corresponding surfaces on the tool holder (22), each driven surface (58) facing the rotational direction (R), and each radial centering surface (62) facing radially inward. The plurality of radial centering surfaces (62) are located radially outward from the plurality of driven surfaces (58), Milling head (24).

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

3. The radial centering surface (62) forms a centering surface angle (α) with respect to the head central axis (B), The centering surface angle (α) satisfies the condition 20° ≤ α ≤ 40°. The milling head (24) according to claim 1 or 2.

4. The head through recess (44) comprises a plurality of radially narrow recess portions (50) arranged at angular intervals, and the plurality of radially narrow recess portions (50) are arranged alternately with the tooth receiving lobes (48) along the circumferential surface (46) of the recess. The aforementioned recessed circumferential surface (46) comprises a plurality of recess relief surfaces (66), each recess relief surface (66) located in the respective radially narrowed portion (50) of the recess and facing radially inward. A milling head (24) according to any one of claims 1 to 3.

5. The milling head (24) according to any one of claims 1 to 4, wherein the plurality of radial centering surfaces (62) define a virtual recess outermost cylinder (OC) that is centered with respect to the head central axis (B).

6. The head through recess (44) comprises a plurality of radially narrow recess portions (50) arranged at angular intervals, and the plurality of radially narrow recess portions (50) are arranged alternately with the tooth receiving lobes (48) along the circumferential surface (46) of the recess. The aforementioned recessed circumferential surface (46) comprises a plurality of recess relief surfaces (66), each recess relief surface (66) located in the respective radially narrowed portion (50) of the recess and facing radially inward. The plurality of recess relief surfaces (66) define the innermost virtual recess (IC) which is coaxial with the outermost virtual recess (OC), The virtual recess innermost cylinder (IC) has a recess innermost cylindrical radius (IR), The outermost cylinder of the virtual recess (OC) has an outermost cylinder radius of the recess (OR), The innermost cylindrical radius (IR) of the recess is 75% or less of the outermost cylindrical radius (OR) of the recess. The milling head (24) according to claim 5.

7. It is provided with a plurality of fastening through holes (67) arranged at an angle, the plurality of fastening through holes (67) opening on the front and rear surfaces (26, 28) of the head and spaced apart from the head through recess (44), Each fastening through hole (67) is located between two angularly adjacent tooth receiving lobes (48) of the head through recess (44). The milling head (24) according to claim 5 or 6.

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 virtual recess or intersect with the outermost cylinder (OC) of the virtual recess.

9. Each fastening through-hole (67) extends along its respective fastening through-hole axis (F), The fastening through-hole axis (F) is located inside the outermost cylinder (OC) of the virtual recess. The milling head (24) according to claim 7 or 8.

10. The circumferential surface of the recess (46) has a recess height (H) measured in the axial direction, The plurality of radial centering surfaces (62) and the plurality of driven surfaces (58) extend over the entire recess height (H), A milling head (24) according to any one of claims 1 to 9.

11. The milling head (24) according to any one of claims 1 to 10, wherein the head through recess (44) comprises exactly three tooth receiving lobes (48).

12. The milling head (24) according to any one of claims 1 to 11, wherein all tooth-receiving lobes (48) have exactly one driven surface (58) and exactly one radially centering surface (62) located thereon.

13. The milling head (24) according to any one of claims 1 to 12, wherein the rear surface of the head (28) comprises at least one planar axial bearing surface (64a, 64b) facing rearward, and the axial bearing surfaces (64a, 64b) extend along the entire angular range of the rear surface of the head (28).

14. Each tooth receiving lobe (48) comprises a narrow lobe portion (LN) and a wide lobe portion (LW) located radially outward from the narrow lobe portion (LN). The wide portion of the lobe (LW) has a first maximum width (w1), and the narrow portion of the lobe (LN) has a second maximum width (w2). The first maximum width (w1) is greater than the second maximum width (w2). A milling head (24) according to any one of claims 1 to 13.

15. The head through recess (44) includes a central region (51) connected 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 range of the central region (51). A milling head (24) according to any one of claims 1 to 14.

16. A tool holder (22) having a holder central axis (C), wherein the holder central axis (C) is in opposite directions, forward and backward (D Ｆ , D Ｒ The tool holder (22) is defined to be rotatable in the rotational direction (R) about the holder central axis (C), and the tool holder (22) is The shank circumferential surface (72) extends in the circumferential direction with respect to the holder central axis (C), The shank front end surface (70) is bounded by the shank circumferential surface (72) located at the front end of the tool holder (22), A shank projection (74) protrudes from the front end face (70) of the shank along the holder central axis (C), wherein the shank projection (74) has a boundary defined in the circumferential direction by the circumferential surface (76) of the projection and comprises a plurality of centering drive teeth (78) arranged at angular intervals, the plurality of centering drive teeth (78) extending radially outward, and the shank projection (74) comprises The circumferential surface (76) of the protrusion comprises a plurality of drive surfaces (82) and a plurality of radial alignment surfaces (84), all of which are located on the plurality of centering drive teeth (78) and are configured to contact corresponding surfaces on the milling head (24), each drive surface (82) facing the rotational direction (R), and each radial alignment surface (84) facing radially outward. The plurality of radial alignment surfaces (84) are located radially outward from the plurality of drive surfaces (82), Tool holder (22).

17. The tool holder (22) according to claim 16, wherein the circumferential surface of the convex portion (76) is oriented parallel to the holder central axis (C).

18. Each radial alignment surface (84) forms an alignment surface angle (β) with respect to the longitudinal axis (C) of the holder. The alignment surface angle (β) satisfies the condition 20° ≤ β ≤ 40°. The tool holder (22) according to claim 16 or 17.

19. The shank projection (74) comprises a plurality of radially narrow projections (80) arranged at angular intervals, and the plurality of radially narrow projections (80) are alternately arranged in the circumferential direction with respect to the centering drive teeth (78) along the circumferential surface (76) of the projection. The aforementioned convex circumferential surface (76) comprises a plurality of convex relief surfaces (86), each convex relief surface (86) located on the respective radially narrowed portion (80) and facing radially outward. A tool holder (22) according to any one of claims 16 to 18.

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 a virtual convex portion that is centered on the holder's central axis (C).

21. The shank projection (74) comprises a plurality of radially narrow projections (80) arranged at angular intervals, and the plurality of radially narrow projections (80) are alternately arranged in the circumferential direction with respect to the centering drive teeth (78) along the circumferential surface (76) of the projection. The aforementioned convex circumferential surface (76) comprises a plurality of convex relief surfaces (86), each convex relief surface (86) located on the respective radially narrowed portion (80) and facing radially outward. The plurality of relief surfaces (86) define the innermost virtual convex cylinder (IC') which is coaxial with the outermost virtual convex cylinder (OC'), The virtual innermost cylinder of the protrusion (IC') has an innermost cylinder radius of the protrusion (IR'), The outermost cylinder of the virtual convex portion (OC') has an outermost cylinder radius of the convex portion (OR'), The innermost cylindrical radius (IR') of the protrusion is 75% or less of the outermost cylindrical radius (OR') of the protrusion. The tool holder (22) according to claim 20.

22. It is provided with a plurality of screw holes (88) arranged at an angle, the plurality of screw holes (88) opening on the front end face (70) of the shank and arranged at a distance from the shank protrusion (74), Each screw hole (88) is located between two angularly adjacent centering drive teeth (78). The tool holder (22) according to claim 20 or 21.

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

24. Each screw hole (88) extends along its respective screw hole axis (G), The screw hole shaft (G) is located inside the outermost cylinder (OC') of the virtual protrusion. The tool holder (22) according to claim 22 or 23.

25. The circumferential surface (76) of the protrusion has a protrusion height (H') measured in the axial direction. The plurality of radial alignment surfaces (84) and the plurality of drive surfaces (82) extend over the total height (H') of the protrusion. A tool holder (22) according to any one of claims 16 to 24.

26. The shank projection (74) comprises exactly three centering drive teeth (78), the tool holder (22) according to any one of claims 16 to 25.

27. The tool holder (22) according to any one of claims 16 to 26, wherein all centering drive teeth (78) have 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 shank front end face (70) comprises at least one planar axial support surface (90a, 90b) facing forward, and the axial support surface (90a, 90b) extends along the entire angular range of the shank front end face (70).

29. A milling head (24) according to any one of claims 1 to 15 and A tool holder (22) according to any one of claims 16 to 28, comprising The milling head (24) is removably mounted on the tool holder (22). The shank projection (74) is located within the head through recess (44), The plurality of radial centering surfaces (62) directly contact the plurality of radial alignment surfaces (84) of the shank protrusion (74), The plurality of driven surfaces (58) are in direct contact with the plurality of driving surfaces (82), Rotary milling tool (20).

30. The head rear surface (28) is provided with at least one rearward-facing planar axial bearing surface (64a, 64b) that extends along its entire angular range, The shank front end surface (70) is provided with at least one forward-facing planar axial support surface (90a, 90b) extending along its entire angular range, The at least one axial bearing surface (64a, 64b) abuts against the at least one axial support surface (90a, 90b), The rotary milling tool (20) according to claim 29.

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