The present invention relates to rotary cutting tools in general, and to rotary cutting tools configured to form multiple surfaces in particular.
Rotary cutting tools can be used to produce a bore geometry with a plurality of independent surfaces. A non-limiting example of a bore geometry with a plurality of independent surfaces is a valve seat.
A “three-angle” valve seat is diagrammatically shown in
Conventional rotary cutting tools configured to produce a multiple surface configuration like a valve seat often include independent cutting teeth for each surface to be formed. For example, a prior art rotary cutting tool may have a pair of first teeth disposed to cut the primary surface, a pair of second teeth disposed to cut the secondary surface, and a pair of third teeth disposed to cut the tertiary surface. A disadvantage of this type of cutting tool arrangement is that the number of teeth that can be deployed around the circumference of the rotary cutting tool is limited; e.g., each tooth is circumferentially displaced from other cutting teeth, and for a given rotary cutting tool circumference, the number of circumferential positions is limited. The limited circumferential space issue is particularly acute for those prior art cutting tools that use cartridge mounted teeth. The cartridges facilitate removal and replacement of worn teeth, but take up a considerable amount of circumferential space, and in some instances can produce tool set up issues.
What is needed is a rotary cutting tool having cutting elements that can be used to create a plurality of independent surfaces without the limitations of the prior art.
According to an aspect of the present disclosure, a rotary cutting tool having a rotational axis is provided that includes a shank and a body. The body extends axially outwardly from the shank. The body has a plurality of first teeth and a plurality of second teeth. The first teeth and the second teeth are alternately arranged and spaced apart from one another around a circumference. Each first tooth includes a primary cutting edge disposed at a primary angle relative to the rotational axis and a tertiary cutting edge disposed at a tertiary angle relative to the rotational axis. Each second tooth includes a secondary cutting edge disposed at a secondary angle relative to the rotational axis. The secondary cutting edge is disposed axially between the primary cutting edge and the tertiary cutting edge.
In any of the aspects described above or herein, the secondary angle may be different from the primary angle and the tertiary angle.
In any of the aspects described above or herein, the primary angle may be different from the tertiary angle.
In any of the aspects described above or herein, the primary cutting edge and the tertiary cutting edge may be axially separated from one another.
In any of the aspects described above or herein, the primary cutting edge and the secondary cutting edge may axially intersect one another.
In any of the aspects described above or herein, the tertiary cutting edge and the secondary cutting edge may axially intersect one another.
In any of the aspects described above or herein, the rotary cutting tool may further comprise a plurality of flutes, each said flute disposed between an adjacent one said first tooth and a one said second tooth.
In any of the aspects described above or herein, the rotary cutting tool may include one or more coolant passages extending within the body.
In any of the aspects described above or herein, the one or more coolant passages may include at least one passage in fluid communication with an exit port disposed within a flute.
In any of the aspects described above or herein, the rotary cutting tool may include a first axial end and a second axial end opposite the first axial end, and the shank may extend between the first axial end and the body, and the plurality of first teeth and the plurality of second teeth may be disposed within a first cutter head portion, and the body may include a second cutter head portion extending from the second axial end toward the first cutter head portion.
In any of the aspects described above or herein, the second cutter head portion may include a reamer.
In any of the aspects described above or herein, the rotary cutting tool may include a first portion and a second portion that are fixed to one another, the first portion including the shank and at least a segment of the body, wherein the first portion is formed of a first material and the second portion is formed of a second material, and the first material is different from the second material.
In any of the aspects described above or herein, each first tooth may include a first tip fixed thereto, and the first tip is configured to include the primary cutting edge and the tertiary cutting edge, and each second tooth may include a second tip fixed thereto, and the second tip is configured to include the secondary cutting edge.
In any of the aspects described above or herein, each first tooth may include a first cutting insert mechanically attached to the first tooth, and the first cutting insert is configured to include the primary cutting edge and the tertiary cutting edge, and each second tooth may include a second cutting insert mechanically attached to the second tooth, and the second cutting insert is configured to include the secondary cutting edge.
According to an aspect of the present disclosure, a rotary cutting tool having a rotational axis is provided. The rotary cutting tool includes a shank and a body. The body has a plurality of first teeth and a plurality of second teeth. The first teeth and second teeth are alternately arranged and spaced apart from one another around a circumference. Each first tooth includes a primary cutting edge disposed at a primary angle relative to the rotational axis and a tertiary cutting edge disposed at a tertiary angle relative to the rotational axis. Each second tooth includes a secondary cutting edge disposed at a secondary angle relative to the rotational axis. The primary cutting edge, the secondary cutting edge, and the tertiary cutting edge are configured such that rotation of the tool and engagement of the tool into a workpiece causes: the primary cutting edge and the secondary cutting edge to form a primary surface and a secondary surface in a work piece, the primary surface and the secondary surface contiguous with one another; and the tertiary cutting edge to form a tertiary surface in the work piece, the secondary surface and the tertiary surface contiguous with one another; and the primary surface axially separated from the tertiary surface.
In any of the aspects described above or herein, the secondary angle may be different from the primary angle and the tertiary angle, the primary angle may be different from the tertiary angle, and the primary cutting edge and the tertiary cutting edge may be axially separated from one another.
In any of the aspects described above or herein, the primary cutting edge and the secondary cutting edge may axially intersect one another, and the tertiary cutting edge and the secondary cutting edge may axially intersect one another.
In any of the aspects described above or herein, the rotary cutting tool may include a plurality of flutes, each said flute disposed between an adjacent one said first tooth and a one said second tooth.
In any of the aspects described above or herein, the rotary cutting tool may include a first axial end and a second axial end opposite the first axial end, and the shank may extend between the first axial end and the body, and the plurality of first teeth and the plurality of second teeth may be disposed within a first cutter head portion, and the body may include a second cutter head portion extending from the second axial end toward the first cutter head portion.
In any of the aspects described above or herein, the second cutter head portion may include a reamer.
The present disclosure is directed to a rotary cutting tool configured to produce a workpiece bore geometry with a plurality of independent surfaces. The term “plurality of independent surfaces” as used herein means at least three surfaces; i.e., at least a primary surface, a secondary surface, and a tertiary surface. The secondary surface is disposed between and is contiguous with the primary surface and the tertiary surface; i.e., the secondary surface extends axially between the primary and tertiary surfaces. The primary and tertiary surfaces are axially separated from one another.
The present disclosure rotary cutting tool can be configured in a variety of different embodiments that may be used for a variety of different applications. The rotary cutting tool has first teeth and second teeth. Each first tooth is configured to cut a primary surface and a tertiary surface. Each second tooth is configured to cut a secondary surface. A plurality of the first teeth and a plurality of the second teeth are disposed around the circumference of the rotary cutting tool. The first teeth (“FT”) and second teeth (“ST”) are alternately disposed around the circumference of the rotary cutting tool (i.e., FT, ST, FT, ST, etc.). The first and second teeth may be uniformly spaced apart from one another around the circumference of the tool, but the present disclosure is not limited to uniformly spaced teeth. Each first tooth includes a primary cutting edge and a tertiary cutting edge. The primary cutting edge is disposed at a primary surface angle. The tertiary cutting edge is disposed at a tertiary surface angle. Each second tooth has a secondary cutting edge disposed at a secondary surface angle. Each of the respective surface angles may be defined as an included angle between the respective cutting edge and a radial line extending perpendicular to the rotational axis of the rotary cutting tool, or alternatively as an included angle between the respective cutting edge and the rotational axis. The primary and tertiary surface angles are different from the secondary angle. Depending on the application, the rotary cutting tool may be configured so that the primary, secondary, and tertiary angles are all different from one another. The primary cutting edge and the tertiary cutting edge are axially separated from one another. In some embodiments, the primary cutting edge and the tertiary cutting edge may intersect one another within a first tooth. The secondary cutting edge is disposed axially between the primary and tertiary cutting edges. The primary cutting edge and the secondary cutting edge axially intersect one another (but are circumferentially separated from one another); e.g., the primary cutting edge is circumferentially separated from the secondary cutting edge, and the primary cutting edge and the secondary cutting edge axially overlap one another. The secondary cutting edge and the tertiary cutting edge axially intersect one another (but are circumferentially separated from one another); e.g., the secondary cutting edge is circumferentially separated from the tertiary cutting edge, and the secondary cutting edge and the tertiary cutting edge axially overlap one another. The relative positions of the primary, secondary, and tertiary cutting edges are such that during use of the rotary cutting tool, the primary and secondary cutting edges form contiguous primary and secondary surfaces in the workpiece, and the secondary and tertiary cutting edges form contiguous secondary and tertiary surfaces in the workpiece.
Non-limiting examples of a present disclosure rotary cutting tool are shown in
The rotary cutting tool 20 embodiments shown in
The body section 40 is disposed axially between the shank 28 and the first cutter head portion 36. In the embodiments shown in
The first cutter head portion 36 is disposed axially between the body section 40 and the second cutter head portion 38. In the embodiments shown in
A flute 50 may be disposed between each first tooth 46 and second tooth 48 pair; e.g., FT, flute, ST, flute, FT, flute, ST, etc. Each flute 50 is configured to facilitate removal of workpiece chips produced during use of the rotary cutting tool 20. The flute 50 embodiments shown in
Each first tooth 46 includes a primary cutting edge 64 and a tertiary cutting edge 66. The primary cutting edge 64 is disposed at a primary surface angle “α”. The primary surface angle is shown in
In some embodiments, the rotary cutting tool 20 may be configured such that each first tooth 46 and/or each second tooth 48 is formed of a single body of material (e.g., steel or carbide). In these embodiments, each first tooth 46 is formed (e.g., machined) to include the primary cutting edge 64 and the tertiary cutting edge 66, and each second tooth 48 is formed (e.g., machined) to include the secondary cutting edge 72.
In some embodiments, the rotary cutting tool 20 may be configured such that a cutting tip is attached to each first tooth 46 and/or each second tooth 48. For example, a cutting tip (e.g., a body formed independently from the tooth) may be disposed within a pocket (not shown) formed within the respective tooth 46, 48 and attached to the tooth 46, 48; e.g., by a brazing process, or by an adhesive, or other material capable of fixing the cutting tip within the pocket. For those first teeth 46 that include a cutting tip, the cutting tip is formed (e.g., machined) to include the primary cutting edge 64 and the tertiary cutting edge 66. For those second teeth 48 that include a cutting tip, the cutting tip is formed (e.g., machined) to include the secondary cutting edge 72. Alternatively, a cutting tip may be fixed to the respective tooth as described and the respective cutting edge 64, 66, 72 may be formed subsequently. The cutting tips may comprise a different material than that of the respective tooth 46, 48; e.g., the teeth 46, 48 comprising steel and the cutting tips comprising a carbide, or a polycrystalline diamond (PCD) material, or a cubic boron nitride material, etc. The present disclosure is not limited to cutting tips comprised of any particular material.
In some embodiments, the rotary cutting tool 20 may be configured with each first tooth 46 and/or each second tooth 48 includes a cutting insert 76. For example, a cutting insert 76 may be disposed within a pocket (not shown) formed within the respective tooth and attached to the tooth by mechanical fastener 78; e.g., attached by a screw, etc. The cutting insert 76 is, therefore, removably attached to the respective tooth 46, 48 and can be replaced when desired; e.g., if worn, or if different cutting edge angles are desired, etc. For those first teeth 46 that include a cutting insert 76, the cutting insert 76 is formed (e.g., machined) to include the primary cutting edge 64 and the tertiary cutting edge 66. For those second teeth 48 that include a cutting insert 76, the cutting insert 76 is formed (e.g., machined) to include the secondary cutting edge 72. The cutting inserts 76 may comprise a different material than that of the respective tooth; e.g., the teeth 46, 48 comprising steel and the cutting inserts 76 comprising a carbide, or a polycrystalline diamond (PCD) material, or a cubic boron nitride material, etc. The present disclosure is not limited to cutting inserts 76 comprised of any particular material.
In some embodiments, the present disclosure rotary cutting tool 20 may be a one-piece structure comprising a single material throughout (e.g., the rotary cutting tool 20 is formed from a single body of material), with the possible exception of cutting tips or cutting inserts as described above.
In some embodiments, the present disclosure rotary cutting tool 20 may be an assembly formed from a plurality of elements. For example, in the diagrammatic partial cross-section shown in
In some embodiments, the present disclosure rotary cutting tool 20 may include internal passages that permit the passage of cutting fluids. For example, a rotary cutting tool 20 may include one or more axial passages 88 extending from the first axial end 24, and one or more radial passages 90 that extend between the axial passage(s) 88 to the exterior of the rotary cutting tool 20. The rotary cutting tool 20 embodiments shown in
During operation of a present disclosure the rotary cutting tool 20, the rotary cutting tool 20 is mounted within a machine tool (not shown) for rotation at one or more predetermined rotational speeds and one or more axial feed rates. The axial feed rate reflects the rate of linear movement that the rotary cutting tool 20 is engaging the workpiece 94 (see
Valve seats utilized within an internal combustion engine typically have a relatively small diameter. Hence, a rotary cutting tool 20 configured to produce such a valve seat must also have a correspondingly small diameter. As stated above, conventional rotary cutting tools typically include one cutting edge per cutting tooth, and depending on the rotary cutting tool may include a single tooth per surface to be formed; e.g., a first tooth (FT) that cuts a primary surface, a second tooth (ST) that cuts a secondary surface, and a third tooth (TT) that cuts a tertiary surface, or a pair of first teeth, a pair of second teeth, and a pair of third teeth, if the tool circumference permits.
As a general rule, the useable life of a rotary cutting tool is proportional to the number of cutting edges used to form a given surface. If for example, a rotary cutting tool includes only a single cutting edge for forming a given surface, once that cutting edge is compromised (e.g., develops micro-cracks, rounds out or otherwise changes geometry, etc.) the tool cannot be used. If the rotary cutting tool includes a pair of cutting edges for forming a given surface and one of those cutting edges is compromised, then it is likely that the tool will still be able to form the given surface within specification due to the remaining cutting edge that has not been compromised. However, once the second cutting edge is compromised, the tool likely cannot be used.
The present disclosure rotary cutting tool 20 provides a significant improvement to the prior art rotary cutting tools. For example, a tool 20 with six circumferential positions: three first teeth 46 (FT) that each cut primary and tertiary surfaces, and three second teeth 48 (ST) that each cut a secondary surface (FT, ST, FT, ST, FT, ST; see
It is noted that various connections are set forth between elements in the present description and drawings (the contents of which are included in this disclosure by way of reference). It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. A coupling between two or more entities may refer to a direct connection or an indirect connection. An indirect connection may incorporate one or more intervening entities or a space/gap between the entities that are being coupled to one another.
Furthermore, any reference to singular includes plural embodiments, and any reference to more than one component or step may include a singular embodiment or step. Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option.
Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112(f) unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprises”, “comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
This application claims priority to U.S. Patent Appln. No. 62/965,604 filed Jan. 24, 2020, which is herein incorporated by reference in its entirety.
Number | Date | Country | |
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62965604 | Jan 2020 | US |