Tool holder with vibration isolation device and cutting tool with tool holder

Abstract

The elongated tool holder includes a tool vibration isolation component having a mass receiving portion and a vibration isolation device. The vibration isolation device includes an internal holder cavity formed within and enclosed within the mass receiving portion. The vibration isolation device also includes a vibration absorbing mass disposed within the holder cavity and resiliently suspended within the holder cavity by at least three non-torus shaped resilient suspension members, the at least three non-torus shaped resilient suspension members contacting an inwardly facing cavity wall surface. The cutting tool includes a tool holder.

Description

[Technical Field]

[0001] The subject matter of this application relates generally to tool holders, particularly to such tool holders having vibration isolators, and even more particularly to such vibration isolators having at least three resilient suspension members. [Background technology]

[0002] The tool holder may include a vibration isolator that isolates the tool holder from vibration during metal cutting operations. Typically, the vibration isolator is a resilient mass system including a cavity and a vibration-absorbing mass suspended within the cavity by a resilient support member. The cavity may be filled with a viscous fluid.

[0003] In some such vibration isolation devices, the resilient support member may be formed from an annular structure (i.e., an O-ring). Examples of such tool retention systems are disclosed, for example, in US 9,579,730, US 2016 / 305503, US 7,234,379, US 6,443,673 and US 3,774,730.

[0004] In other such vibration-damping devices, the elastic support member may be formed from a spherical elastic body. One example of such a tool holding system is described in JP 2008-100332 A, which discloses a vibration-damping tool having a weight that is elastically supported in a hollow portion of a tool body by two approximately spherical elastic bodies. The center of the weight and tool body is formed in a conical recess so that the end faces of the weight that contact the tool body and the spherical elastic bodies can easily coincide with the axial centers of the weight and tool body. Summary of the Invention [Problem to be solved by the invention]

[0005] It is an object of the subject matter of the present application to provide a new and improved vibration isolation device. [Means for solving the problem]

[0006] According to a first aspect of the subject matter of the present application, there is provided a tool holder elongated along a holder longitudinal axis, the tool holder comprising: a mass receiving portion; Vibration isolation device The vibration isolation device comprises: an inner holder cavity formed within the mass receiving portion and having an inwardly facing cavity wall; a vibration-absorbing mass having a mass central axis and including two axially opposed mass ends and at least three mass recesses; at least three non-torus-shaped elastic suspension members; each suspension member partially located within and projecting outwardly from a respective mass recess; The tool holder is adjustable between an unassembled state and an assembled state, and in the assembled state: The vibration-absorbing mass is disposed within the internal holder cavity and is resiliently suspended within the internal holder cavity by at least three suspension members that contact the inward-facing cavity wall surfaces, thereby forming an oscillation space located between the vibration-absorbing mass and the inward-facing cavity wall surfaces.

[0007] According to a second aspect of the subject matter of the present application, there is provided a cutting tool, the cutting tool comprising: a tool holder of the type described above; a cutting portion having at least one cutting insert; Equipped with.

[0008] It should be understood that the above is a summary and that the features described below may be applicable to the subject matter of the present application in any combination, for example, any of the following features may be applicable to a tool holder or a cutting tool:

[0009] The at least three suspension members may undergo compressive elastic deformation due to contact with the inward-facing cavity wall surface and the respective mass recess.

[0010] The at least three suspension members may be formed from a material different from the material of the vibration absorbing mass.

[0011] In an unassembled state, the vibration-absorbing mass can be disposed outside the internal holder cavity, and each of the at least three suspension members can be releasably retained within a respective one of the at least three mass recesses of the vibration-absorbing mass by each suspension member contacting only the outer circumferential surface of a respective one of the at least three mass recesses, thereby undergoing compressive elastic deformation.

[0012] Each of the at least three suspension members may have a spherical shape defined by a suspension member radius.

[0013] The vibration absorbing mass may be elongated along a central mass axis.

[0014] In the assembled state of the tool holder, the mass central axis may be parallel to the holder longitudinal axis.

[0015] The mass central axis may coincide with the holder longitudinal axis.

[0016] The vibration absorbing mass may have a constant cross-sectional area in a plane perpendicular to the mass central axis.

[0017] In an end view of the vibration-absorbing mass, each mass recess can subtend a mass recess angle from the mass central axis. For any given mass end having two or more mass recesses, the mass recesses can be equally spaced apart from each other about the mass central axis by a recess separation angle. The recess separation angle can be less than the mass recess angle.

[0018] At least three mass recesses may be formed in two opposing mass ends, with at least one mass recess formed in each mass end.

[0019] The vibration-absorbing mass may include two mass end faces and a mass outer periphery extending between the two mass end faces about a mass central axis, the two mass end faces and the mass outer periphery intersecting to form two mass edges, and each of the at least three mass recesses may be at least partially formed in one of the two mass end faces.

[0020] Each of the at least three mass recesses may be partially formed in one of the two mass end faces and partially formed in the mass outer periphery so as to intersect one of the two mass edges.

[0021] Each mass end face may be rotationally symmetric about the mass central axis.

[0022] The two mass end faces may be identical.

[0023] The two mass end faces can be offset from each other by a rotation angle about the mass central axis.

[0024] For any mass end having two or more mass recesses, the mass recesses may be offset by an offset angle about the mass central axis at equal angles, and the rotation angle may be equal to half the offset angle.

[0025] Each suspension member may project outwardly from a respective mass recess relative to the mass central axis in both a radial and axial direction.

[0026] The mass outer periphery distal to the mass end surface may have a cylindrical shape defined by the mass radius.

[0027] The at least three suspension members may have a spherical shape defined by a suspension member radius, and the mass radius may be between three and four times the size of the suspension member radius.

[0028] The two mass end faces may be flat and oriented transversely to the mass central axis.

[0029] For any mass end having more than one mass recess, the angles of the mass recesses may be offset from one another about the mass central axis.

[0030] The angles of the mass recesses may be equally offset from one another about the mass central axis by an offset angle.

[0031] The cavity wall surface may comprise two opposite cavity wall end surfaces and a cavity wall outer circumferential surface extending between the two opposite cavity wall end surfaces, the cavity wall outer circumferential surface extending about the cavity central axis. In the assembled position of the tool holder, each suspension member may simultaneously abut the cavity wall outer circumferential surface and one of the two flat cavity wall end surfaces.

[0032] The two cavity wall end faces may be flat.

[0033] The vibration absorbing mass may include an equal number N of mass recesses at each mass end.

[0034] N may be equal to 6.

[0035] The at least three mass recesses may be formed in two opposite mass ends (60). The vibration isolator may include an adjustment member displaceable along the cavity central axis and abutting the suspension member at one of the mass ends.

[0036] The adjustment member may comprise a flat adjustment abutment surface, which may abut against said suspension member at said one of the mass ends.

[0037] The oscillation space may be free of viscous fluid.

[0038] The mass housing portion may include a first metallic material. The vibration absorbing mass may include a second metallic material. The second metallic material may be denser than the first metallic material.

[0039] The cutting portion may be releasably attachable to the tool holder.

[0040] The vibration isolator may be disposed at the front end of the cutting tool.

[0041] The cutting tool may be a rotary cutting tool designed to rotate about an axis of rotation.

[0042] For a better understanding of the present application and to show how it may be carried into practice, reference should now be made to the accompanying drawings, in which: [Brief explanation of the drawings]

[0043] [Figure 1] 1 is a perspective view of a cutting tool according to the present application showing an anti-vibration device; [Figure 2] FIG. 2 is an exploded perspective view of the tool holder of FIG. 1 according to the present application. [Figure 3] FIG. 3 is an axial cross-sectional view of the tool holder of FIG. 2. [Figure 4] 4 is a radial cross-sectional view of the tool holder of FIG. 2 taken along line IV-IV of FIG. 3; [Figure 5] FIG. 3 is a perspective view of the vibration isolation device of FIG. 2. [Figure 6] FIG. 2 is an exploded perspective view of components of the vibration isolation device of FIG. 1. [Figure 7] FIG. 6 is a side view of the components of the vibration isolation device of FIG. 5. [Figure 8] FIG. 6 is an end view of the components of the vibration isolation device of FIG. 5. [Figure 9] 9 is a radial cross-sectional view of a part of the vibration isolator of FIG. 5 taken along line IX-IX of FIG. 7; DETAILED DESCRIPTION OF THE INVENTION

[0044] It will be understood that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity, or several physical components may be subsumed within a single functional block or element. Furthermore, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.

[0045] In the following description, various aspects of the subject matter of the present application are described. For purposes of explanation, specific configurations and details are shown in sufficient detail to provide a thorough understanding of the subject matter of the present application. However, it will be apparent to one skilled in the art that the subject matter of the present application may be practiced without the specific configurations and details presented herein.

[0046] Attention is first directed to FIG. 1 , which illustrates a cutting tool 20 for chip removal. FIG. 1 illustrates one aspect of the present application. The cutting tool 20 has a tool longitudinal axis A. According to some embodiments of the present subject matter, the cutting tool 20 may be a rotary cutting tool. That is, the cutting tool 20 is designed to rotate about an axis of rotation. In this illustrated, non-limiting example, the cutting tool 20 is a milling tool. However, the present subject matter is not limited to milling tools and may also be applicable to, for example, but not limited to, drilling tools. The present subject matter may also be applicable to non-rotating cutting tools, such as boring bars. In the case of such non-rotating cutting tools, the cutting tool 20 is not designed to be rotatable in a rotational direction about the tool longitudinal axis A.

[0047] The cutting tool 20 includes a tool holder 22. The cutting tool 20 also includes a cutting portion 24 that includes at least one cutting insert 26. The at least one cutting insert 26 is designed to perform a metal-cutting operation and, for this purpose, has a cutting edge. According to some embodiments of the subject matter of the present application, the at least one cutting insert 26 may be releasably attached to the cutting portion 24. The cutting portion 24 may be integrally formed with the tool holder 22. Alternatively, the cutting portion 24 may be releasably attached to the tool holder 22. The cutting portion 24 may be disposed at a front end of the tool holder 22.

[0048] Please refer to Fig. 2, which shows a tool holder 22. Fig. 2 shows another embodiment of the present application. The tool holder 22 is oriented in the opposite forward direction D. F and backward D RThe tool holder 22 has a holder longitudinal axis B that defines a center axis B. The tool holder 22 is elongated along the holder longitudinal axis B. According to some embodiments of the subject matter of the present application, the cutting tool 20 and the tool holder 22 may be coaxial with each other. It should be noted that two elements (e.g., in this case the cutting tool 20 and the tool holder 22) are coaxial with each other when their longitudinal axes coincide (are aligned with each other).

[0049] It should be further noted that the use of the terms "front" and "rear" throughout the specification and claims refers to relative positions toward the left and right, respectively, in FIG. 3 in the direction of the holder longitudinal axis B. Generally, the front direction is toward the cutting portion 24.

[0050] According to some embodiments of the subject matter of the present application, the tool holder 22 may include two opposing holder end faces 30 and a holder outer periphery 32 extending between the two opposing holder end faces 30. The holder outer periphery 32 may extend about a holder longitudinal axis B.

[0051] The tool holder 22 includes a mass receiving portion 40 and a vibration isolator 34. The tool vibration isolator 34 is designed to reduce or eliminate vibrations of the cutting tool 20 when the cutting tool 20 performs a metal cutting operation. According to some embodiments of the subject matter of the present application, the vibration isolator 34 may be disposed at a front end of the cutting tool 20.

[0052] The vibration isolator 34 includes an internal holder cavity 36 formed within the mass receiving portion 40. That is, the internal holder cavity 36 is enclosed within the mass receiving portion 40. The holder cavity 36 is defined by an inwardly facing cavity wall 38. The cavity wall 38 demarcates the holder cavity 36 from the mass receiving portion 40. The mass receiving portion 40 surrounds the holder cavity 36. The holder cavity 36 has a cavity central axis D. According to some embodiments of the subject matter of the present application, the holder cavity 36 may be elongated along the cavity central axis D. The holder cavity 36 may be elongated in the same direction as the tool holder 22. In particular, the holder cavity 36 may be coaxial with the tool holder 22. The cavity wall 38 may include two opposing cavity wall end surfaces 42 and a cavity wall perimeter surface 44 extending between the two opposing cavity wall end surfaces 42. The cavity wall perimeter surface 44 may extend about the cavity central axis D.

[0053] See also FIG. 3 , which shows an axial cross-section of the holder cavity 36 through the cavity wall outer periphery 44 (taken in a plane containing the cavity central axis D). The holder cavity 36 has a cavity cross-section. According to some embodiments of the subject matter of the present application, the cavity cross-section may be uniform along the cavity central axis D. The cavity wall outer periphery 44 may have a generally cylindrical shape. The cavity wall outer periphery 44 may have a cylindrical shape near two cavity wall end faces 42 (which abut the suspension member 62, as described later in this specification). The two cavity wall end faces 42 may be flat and oriented transversely to the cavity central axis D. The two cavity wall end faces 42 may be oriented perpendicular to the cavity central axis D.

[0054] 1 and 2, the vibration isolator 34 also includes a vibration-absorbing mass 54. According to some embodiments of the present subject matter, the vibration-absorbing mass 54 may be rigid. In some embodiments, the mass-receiving portion 40 may be formed from a first metallic material, such as steel, while the vibration-absorbing mass 54 may be formed from a second, more dense metallic material, such as tungsten.

[0055] 4-7 , the vibration absorbing mass 54 has a central mass axis E. The vibration absorbing mass 54 includes two axially opposed mass end faces 60. The two axially opposed mass end faces 60 are spaced apart from one another along the central mass axis E. According to some embodiments of the subject matter of the present application, the vibration absorbing mass 54 may include two opposed mass end faces 56 and a peripheral mass surface 58 extending between the two opposed mass end faces 56. The peripheral mass surface 58 may extend about the central mass axis E. The two mass end faces 56 are located at the two mass ends 60, respectively. The two mass end faces 56 and the peripheral mass surface 58 may intersect to form two mass edges 61. The vibration absorbing mass 54 may be elongated along the central mass axis E. The vibration absorbing mass 54 may have a substantially constant cross-sectional area in a plane perpendicular to the central mass axis E.

[0056] 2 and 5-7, the vibration-absorbing mass 54 includes at least three mass recesses 64. Each mass recess 64 is recessed into the vibration-absorbing mass 54. The at least three mass recesses 64 are designed to receive a suspension member, as described later in this specification. Each mass recess 64 is defined by a mass recess outer periphery 66. According to some embodiments of the present subject matter, the at least three mass recesses 64 may be identical. The at least three mass recesses 64 may be concave. The at least three mass recesses 64 may have a partially spherical basic shape. That is, each mass recess outer periphery 66 may lie substantially on an imaginary sphere and point inward toward the center of the imaginary sphere.

[0057] As best shown in FIG. 6 , according to some embodiments of the present subject matter, at least three mass recesses 64 can be formed in two opposing mass ends 60, with at least one mass recess 64 formed in each mass end 60. Each of the at least three mass recesses 64 can be at least partially formed in the two mass end faces 56. In particular, each of the at least three mass recesses 64 can be disposed around the circumference of the vibration-absorbing mass 54. Each of the at least three mass recesses 64 can be partially formed in one of the two mass end faces 56 and partially formed in the mass outer surface 58 so as to intersect one of the two mass edges 61. None of the at least three mass recesses 64 intersects the mass central axis E. Note that the at least three mass recesses 64 are not annular recesses extending around the entire 360° circumferential extent of the cavity central axis D. Therefore, the mass recesses 64 are not suitable for receiving an O-ring.

[0058] 8, for mass end portions 60 having two or more mass recesses 64, the angles of the mass recesses 64 may be offset from one another about the mass central axis E. The angles of the mass recesses 64 may be equally offset from one another about the mass central axis E by an offset angle γ. Such a configuration provides stable, resilient suspension for the vibration-absorbing mass 54 within the internal holder cavity 36. In an end view of the vibration-absorbing mass 54, for any given mass end portion 60 having two or more mass recesses 64, the angles of the mass recesses 64 may be equally spaced apart from one another about the mass central axis E by a recess separation angle θ.

[0059] According to some embodiments of the present subject matter, the vibration absorbing mass 54 may include an equal number, N, of mass recesses 64 at each mass end 60 (N is 2 or greater), thereby forming a total of 2×N mass recesses 64 in the vibration absorbing mass 54. In the non-limiting example shown, N may be equal to 6 (i.e., six at each mass end 60, for a total of 12 mass recesses 64).

[0060] Referring to Figure 7, according to some embodiments of the present subject matter, the mass end faces 56 may be flat and oriented perpendicular to the mass central axis E. Referring to Figure 8, the mass outer surface 58 distal to the mass end faces 56 may have a cylindrical shape defined by a mass radius R2. Each mass end face 56 (including any mass recesses 64 located therein) may be rotationally symmetric about the mass central axis E. The two mass end faces 56 may be identical. The angles of the two mass end faces 56 may be offset from one another by a rotational angle α about the mass central axis E.

[0061] The rotation angle α may be equal to one-half the offset angle γ. In other words, in a view along the mass central axis E, for any given adjacent pair of mass recesses 64 on a given mass end face 56, the angle of the mass recesses 64 on the opposite mass end face 56 is exactly midway between the mass recesses 64 of the given adjacent pair. With reference to FIG. 8 , in an end view of the vibration-absorbing mass 54, each mass recess 64 subtends a mass recess angle β from the mass central axis E. The mass recess angle β is defined by the angular extremities of the mass recesses 64 about the mass central axis E. The recess separation angle θ may be less than the mass recess angle β.

[0062] According to some embodiments of the present subject matter, the cavity wall outer surface 44 can have a shape that matches the shape of the mass outer surface 58. One or both of the two cavity wall end surfaces 42 can have a shape that matches the shape of the corresponding mass end surface 56. Thus, the holder cavity 36 can have a shape that matches the shape of the vibration-absorbing mass 54.

[0063] The vibration isolator 34 includes at least three resilient suspension members 62. Each suspension member 62 is defined by a suspension member perimeter 63. The at least three suspension members 62 are resiliently deformable. According to some embodiments of the present subject matter, the number of suspension members 62 may match the number of mass recesses 64. The at least three suspension members 62 may be formed from a material different from the material of the vibration-absorbing mass 54. In some embodiments, the suspension members 62 are made from rubber having a durometer hardness between 60A and 95A.

[0064] The at least three suspension members 62 are non-torus shaped (i.e., non-annular). That is, the at least three suspension members 62 are not O-rings. According to some embodiments of the present subject matter, the at least three suspension members 62 may generally have a shape corresponding to the shape of the at least three mass recesses 64. The at least three suspension members 62 may be balls. The at least three suspension members 62 may have a spherical shape (i.e., balls). That is, each suspension member outer surface 63 may lie on an imaginary sphere and point outward from the center of the imaginary sphere. With reference to FIGS. 8 and 9, each suspension member 62 may be defined by a suspension member radius R1. The mass radius R2 may be between 3 and 4 times the size of the suspension member radius R1. In other words, the mass radius R2 may be between 300% and 400% the size of the suspension member radius R1. Preferably, the mass radius R2 may be between 325% and 375% of the magnitude of the suspension member radius R1. The at least three suspension members 62 may be solid, i.e., the at least three suspension members 62 are not hollow. The at least three suspension members 62 are not fluid.

[0065] The tool holder 22 is adjustable between an unassembled state and an assembled state. In the unassembled state of the tool holder 22, the vibration-absorbing mass 54 is disposed outside the internal holder cavity 36. According to some embodiments of the subject matter of the present application, each of the at least three suspension members 62 can be releasably retained within a respective one of the at least three mass recesses 64 of the vibration-absorbing mass 54 by contacting only the mass recess outer surface 66 of each of the at least three mass recesses 64, thereby causing each suspension member 62 to undergo compressive elastic deformation. For example, each suspension member 62 is clamped within its respective mass recess 64, with the suspension member outer surface 63 biased against and abutting the mass recess outer surface 66.

[0066] According to some embodiments of the subject matter of the present application, the tool holder 22 includes a hollow axial sealing member 67, which is axially oriented in a forward direction D Fdefines the holder cavity 36 and seals the holder cavity 36. That is, the cavity axial sealing member 67 forms one of the cavity wall end faces 42. While the holder cavity 36 is not sealed by the cavity axial sealing member 67 (i.e., while the tool holder 22 is in the unassembled position), the vibration absorbing mass 54 may be inserted into the holder cavity 36. It should be noted that the vibration absorbing mass 54 is reversible; that is, the vibration absorbing mass 54 may be inserted into the holder cavity 36 in both longitudinal orientations.

[0067] In the assembled state of the tool holder 22, the vibration-absorbing mass 54 is disposed within the holder cavity 36. The holder cavity 36 is sealed by a cavity axial sealing member 67. Each suspension member 62 is partially located within and protrudes outward from a respective mass recess 64. According to some embodiments of the subject matter of the present application, each suspension member 62 may protrude outward from a respective mass recess 64 both radially and / or axially relative to the mass central axis E. In this non-limiting example shown, the mass recess 64 intersects the mass edge 61, and each suspension member 62 may protrude outward from a respective mass recess 64 both radially and axially. Each suspension member 62 may abut against a cavity wall surface 38. Specifically, in the above-described configuration in which each suspension member 62 can protrude outward from its respective mass recess 64 both radially and axially, each suspension member 62 can simultaneously abut against the cavity wall outer surface 44 and one of the two cavity wall end surfaces 42.

[0068] In the assembled position of the tool holder 22, the vibration absorbing mass 54 may be elongated in the same direction as the tool holder 22, i.e., the mass central axis E may be parallel to the holder longitudinal axis B. In particular, the mass central axis E may be coincident with the holder longitudinal axis B (i.e., the vibration absorbing mass 54 may be coaxial with the tool holder 22).

[0069] In the assembled position of the tool holder 22, the vibration absorbing mass 54 is connected to the mass receiving portion 40 via at least three mass suspension members 62. The vibration absorbing mass 54 is therefore resiliently suspended within the holder cavity 36 by the at least three suspension members 62 contacting the inward-facing cavity wall surface 38. Note that no portion of the mass outer periphery 58 is in direct contact with the inward-facing cavity wall surface 38. According to some embodiments of the subject matter of the present application, the at least three suspension members 62 may undergo compressive elastic deformation due to their contact with the inward-facing cavity wall surface 38 and the respective mass recesses 64.

[0070] In a configuration in which each suspension member 62 projects axially outward from its respective mass recess 64, the suspension members 62 may undergo elastic compressive deformation in the axial direction. Furthermore, in a configuration in which the mass recesses 64 are angularly offset from one another equally about the mass central axis E (such that each suspension member 62 has one or more different suspension members 62 acting in opposition to the mass recess 64), and each suspension member 62 projects radially outward from its respective mass recess 64, the suspension members 62 may also undergo elastic compressive deformation in the radial direction.

[0071] A portion of the suspension member 62 may be located between the mass outer surface 58 and the cavity wall outer surface 44. Similarly, another portion of the suspension member 62 may be located between the mass end surface 56 and the cavity wall end surface 42, thus reducing or even preventing the vibration absorbing mass 54 from impacting the cavity wall end surface 38 during metal cutting operations.

[0072] As an alternative to the above, the cavity wall 38 may include a (preferably conical) recess that receives a portion of each suspension member 62 located away from the outer periphery of the cavity wall end face 42. In this configuration, the suspension members 62 may still undergo compressive elastic deformation in both the radial and axial directions simultaneously. The recess prevents the suspension members 62 from sliding along the cavity wall 38. This is particularly advantageous in configurations having only one suspension member 62 at one of the two mass ends 60.

[0073] The vibration isolator 34 includes an oscillation space 68 formed within the holder cavity 36. The oscillation space 68 is located between the vibration-absorbing mass 54 and the mass-accommodating portion 40 (more specifically, between the vibration-absorbing mass 54 and the inward-facing cavity wall surface 38). In other words, the mass-accommodating portion 40 and the vibration-absorbing mass 54 are separated by the oscillation space 68. According to some embodiments of the present subject matter, the oscillation space 68 completely circumferentially surrounds the vibration-absorbing mass 54. That is, the oscillation space 68 may extend around the entire (360°) angular range of the cavity central axis D. The oscillation space 68 may form an internal annular slot in the vibration-absorbing mass 54.

[0074] The vibration absorbing mass 54 is configured to oscillate within the oscillation space 68 when the at least three suspension members 62 undergo elastic deformation. In other words, the vibration absorbing mass 54 is capable of oscillating displacement within the oscillation space 68 when the at least three suspension members 62 undergo elastic deformation.

[0075] When the cutting tool 20 encounters a workpiece, the cutting tool 20 is subject to vibration. Typically, in the case of a turning or milling cutting operation, the vibration is lateral. Typically, in the case of a drilling cutting operation, the vibration is torsional. The vibration-absorbing mass 54 oscillates at a certain frequency. The vibration isolator 34 is designed to provide a vibration frequency to the vibration-absorbing mass 54 that is close to or the same as the natural frequency of the cutting tool 20, thereby reducing or eliminating the vibration of the cutting tool 20.

[0076] Advantageously, the vibration isolator 34 may be adjustable (such that the vibration frequency of the vibration-absorbing mass 54 matches the natural frequency of the cutting tool 20) without the need to disassemble any individual components. One or more mechanisms, alone or in combination, may be used to modify the frequency at which the vibration-absorbing mass 54 oscillates. In one non-limiting example, a preload may be applied to the at least three suspension members 62. For example, with reference to FIG. 3 , the vibration isolator 34 may include an adjustment member 70 that protrudes into the oscillation space 68. The adjustment member 70 may be formed from the sealing member 67. The adjustment member 70 may abut one or more of the at least three suspension members 62. The adjustment member 70 may be displaceable along the cavity central axis D, thereby adjusting the elastic properties of the at least three suspension members 62. The adjustment member 70 may include a flat adjustment abutment surface 72. The adjustment abutment surface 72 abuts the suspension member 62 at one of the mass ends 60. It should be appreciated that in such a configuration, the adjustment abutment surface 72 forms part of the inwardly facing cavity wall surface 38 .

[0077] According to some embodiments of the subject matter of the present application, the oscillation space 68 may be empty. For example, the oscillation space 68 may be free of viscous fluid.

[0078] The vibration absorbing mass 54 may be made from a second metallic material while the mass housing portion 40 may be made from a first metallic material. Additionally, the use of different second metallic materials (having different densities) may alter the weight of the vibration absorbing mass 54 without changing the dimensions of the vibration absorbing mass 54.

[0079] It should be noted that known vibration isolators that use O-rings for damping require different sized O-rings for masses of different diameters. Conversely, one feature of the present subject matter is that the same size suspension member 62 is suitable for vibration-absorbing masses 54 of different diameters. It should also be noted that O-rings typically require a groove or notch (to receive the O-ring) that extends around the entire 360° circumference of the O-ring. For example, U.S. Pat. No. 6,443,673 discloses a conical surface (i.e., an annular chamfered edge) at the end of the absorbing mass. This notch is formed by removing material, thus undesirably reducing the weight of the mass. Another feature of the present subject matter is that less material is removed from the vibration-absorbing mass 54 to provide angularly spaced mass recesses 64 compared to providing O-rings.

[0080] It is further noted that another feature of the subject matter of the present application is that the vibration isolator 34 is suitable for neutralizing lateral and torsional vibrations.

[0081] It should further be noted that the angular offset of the mass recesses 64 about the mass central axis E at each mass end 60 advantageously provides predetermined contact points by the suspension members 62 on the cavity wall end surfaces 42.

[0082] It is further noted that a configuration where N is greater than or equal to 2 and less than or equal to 8 (with a suspension member located within each mass recess 64) provides optimum vibration damping.

[0083] Although the subject matter of the present application has been described in some detail, it should be understood that various changes and modifications can be made without departing from the spirit or scope of the invention as hereinafter claimed.

Claims

1. A tool holder (22), The tool holder (22) is elongated along a holder longitudinal axis (B) of the tool holder (22) and includes a mass receiving portion (40) and a vibration isolation device (34); The vibration isolation device (34) an internal holder cavity (36) formed within the mass receiving portion (40) and having an inwardly facing cavity wall (38); a vibration-absorbing mass (54) having a mass central axis (E) and comprising two mass end portions (60) and at least three mass recesses (64) positioned opposite each other in a direction along the axis, the at least three mass recesses (64) being formed in the two mass end portions (60), and at least one mass recess (64) being formed in each of the mass end portions (60); At least three non-torus-shaped elastic suspension members (62); Equipped with Each of the non-torus-shaped resilient suspension members (62) is located partially within and projects outwardly from a respective one of the mass recesses (64); The vibration-absorbing mass (54) comprises two mass end faces (56) and a mass outer circumferential surface (58) extending between the mass end faces (56) about the mass central axis (E), the two mass end faces (56) and the mass outer circumferential surface (58) intersecting to form two mass edges (61); each of the at least three mass recesses (64) is at least partially formed in one of the two mass end faces (56); each said non-torus-shaped resilient suspension member (62) projects outwardly from a respective said mass recess (64) relative to said mass central axis (E) in both radial and axial directions; The tool holder (22) is adjustable between an unassembled state and an assembled state, and in the assembled state: the vibration-absorbing mass (54) is disposed within the internal holder cavity (36) and is resiliently suspended within the internal holder cavity (36) by the at least three non-torus-shaped resilient suspension members (62) that contact the inward-facing cavity wall surface (38), thereby forming an oscillation space (68) located between the vibration-absorbing mass (54) and the inward-facing cavity wall surface (38).

2. 2. The tool holder (22) of claim 1, wherein the at least three non-torus-shaped elastic suspension members (62) undergo compressive elastic deformation due to contact with the inwardly facing cavity wall surface (38) and the respective mass recesses (64).

3. The tool holder (22) of claim 1, wherein the at least three non-torus-shaped resilient suspension members (62) are formed from a material different from a material of the vibration absorbing mass (54).

4. In the unassembled state, The vibration absorbing mass (54) is disposed outside the inner holder cavity (36); 4. The tool holder (22) of claim 3, wherein each of the at least three non-torus-shaped resilient suspension members (62) is releasably retained within a respective one of the at least three mass recesses (64) of the vibration-absorbing mass (54), the retention being achieved by each of the non-torus-shaped resilient suspension members (62) contacting only an outer circumferential surface (66) of a respective one of the at least three mass recesses (64) and thereby undergoing compressive elastic deformation.

5. The tool holder (22) of claim 1, wherein each of the at least three non-torus-shaped resilient suspension members (62) has a spherical shape defined by a suspension member radius (R1).

6. In an end view of the vibration absorbing mass (54), each said mass recess (64) subtending a mass recess angle (β) from said mass central axis (E); For any given mass end (60) having two or more mass recesses (64), said mass recesses (64) are equally angularly spaced apart from one another about said mass central axis (E) by a recess separation angle (θ); The tool holder (22) of claim 1, wherein the recess separation angle (θ) is less than the mass recess angle (β).

7. 2. The tool holder (22) of claim 1, wherein each of the at least three mass recesses (64) is partially formed in one of the two mass end faces (56) and partially formed in the mass outer peripheral surface (58) so as to intersect one of the two mass edges (61).

8. 2. The tool holder (22) of claim 1, wherein each said mass end face (56) is rotationally symmetric about said mass central axis (E).

9. A tool holder (22) as described in claim 1, wherein each of the at least three mass recesses (64) is rotationally offset from each other by a rotation angle (α) around the mass central axis (E).

10. A tool holder (22) as described in claim 1, wherein the mass outer surface (58) has a cylindrical shape defined by a mass radius (R2).

11. the at least three non-torus-shaped resilient suspension members (62) have a spherical shape defined by a suspension member radius (R1); The tool holder (22) according to claim 10, wherein the mass radius (R2) is between 3 and 4 times the size of the suspension member radius (R1).

12. 2. The toolholder (22) of claim 1, wherein for any mass end (60) having two or more mass recesses (64), the mass recesses (64) are angularly offset from one another about the mass central axis (E).

13. 13. The tool holder (22) of claim 12, wherein the mass recesses (64) are equally angularly offset from one another by an offset angle (γ) about the mass central axis (E).

14. The cavity wall (38) comprises two opposite cavity wall end faces (42) and a cavity wall outer circumferential surface (44) extending between the two opposite cavity wall end faces (42), the cavity wall outer circumferential surface (44) extending about a cavity central axis (D); 13. The tool holder (22) of claim 12, wherein, in an assembled position of the tool holder (22), each of the non-torus-shaped resilient suspension members (62) simultaneously abuts the cavity wall outer peripheral surface (44) and one of the two cavity wall end surfaces (42).

15. The tool holder (22) of claim 1, wherein the vibration absorbing mass (54) comprises an equal number N of the mass recesses (64) on each of the mass ends (60).

16. 16. The tool holder (22) of claim 15, wherein N=6.

17. the mass receiving portion (40) comprises a first metallic material; the vibration absorbing mass (54) comprises a second metallic material; The tool holder (22) of claim 1, wherein the second metallic material has a higher density than the first metallic material.

18. A cutting tool (20), comprising: A tool holder (22) according to claim 1; a cutting portion (24) comprising at least one cutting insert (26); A cutting tool (20) comprising:

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