Clamping bolt and cutting assembly with clamping bolt

Abstract

A clamping bolt (20) for securing a cutting insert to a cutting tool has a head portion (32), a clamping portion (34) having a clamping surface (44), and a transition portion (36). The clamping bolt (20) has at least one of the following features: the head portion (32) has a protective profile (54) on an axially forward surface (46), the protective profile having a number of projections and / or a number of notches; the clamping portion (34) has a recess (64) having a reinforcing structure (66) comprising a rib (68); the transition portion (36) has a non-circular cross-section perpendicular to a longitudinal extension (26) of the transition portion (36). A cutting assembly having such a clamping bolt (20) is also provided.

Description

Technical Field

[0001] This invention relates to a clamping bolt for fastening a cutting insert to a cutting tool, comprising: a head portion at a first longitudinal end of the clamping bolt; a clamping portion disposed at a second longitudinal end of the clamping bolt opposite the first longitudinal end and having a clamping surface as an engagement surface for fastening elements; and a transition portion connecting the head portion to the clamping portion. Furthermore, this invention relates to a cutting assembly having a cutting tool and a cutting insert, the cutting insert being fastened to the cutting tool by means of such a clamping bolt. Background Technology

[0002] Such clamping bolts and cutting assemblies are known.

[0003] The clamping bolts secure the cutting insert to the cutting tool and bear high loads during the operation of the cutting tool, which limits its service life. Summary of the Invention

[0004] The objective of this invention is to provide clamping bolts that are particularly durable and therefore have a long service life. This invention also aims to provide cutting assemblies having such clamping bolts.

[0005] The task is accomplished by a clamping bolt for fastening a cutting insert to a cutting tool, the clamping bolt comprising: a head portion at a first longitudinal end of the clamping bolt; a clamping portion disposed at a second longitudinal end of the clamping bolt opposite the first longitudinal end and having a clamping surface as an engagement surface of a fastening element; and a transition portion connecting the head portion to the clamping portion. The clamping bolt has at least one of the following features: the head portion has a protective profile on its axially forward surface at the first longitudinal end, wherein the protective profile has a plurality of protrusions and / or a plurality of recesses; the clamping portion has a recess with a reinforcing structure having ribs; and the transition portion has a non-circular cross-section of a longitudinal extension perpendicular to the transition portion.

[0006] According to the present invention, it has been recognized that certain portions of a clamping bolt bear particularly high loads, and that by providing corresponding features to at least one of these portions, the clamping bolt can be designed to be particularly robust and durable.

[0007] Due to the presence of the protrusion, the head portion, typically exposed at the front end during operation, has more material, making it more stable and resistant to chip passage. The notch means the head portion provides a smaller frictional surface for passing chips, thus reducing wear. Furthermore, cooling lubricant can be retained or collected in the notch during operation, improving chip removal. Therefore, the protective profile improves chip removal and protects the clamping bolts from damage.

[0008] The ribs of the reinforced structure advantageously distribute the load across the clamping portion, thereby giving the clamping portion particularly high strength.

[0009] Because the transition section has a non-circular cross-section, it can have a particularly large cross-sectional area and is therefore designed to be particularly stable.

[0010] According to one aspect, the protective profile is not part of the screw head drive component. Therefore, there is no notch in the sense of a slot for a screwdriver or hex wrench.

[0011] Furthermore, according to another aspect, the clamping bolt does not have a screw head drive component.

[0012] In one embodiment, a protrusion protecting the contour is arranged in the edge region, thereby effectively reinforcing this outer region, which is exposed to particularly high loads.

[0013] Alternatively, the notch for protecting the profile can be arranged in the central area of ​​the front surface, thereby particularly effectively reducing friction with chips flowing through the head portion.

[0014] Furthermore, it can be specified that the protrusions and / or recesses of the protective profile are arranged in a rotationally symmetrical manner with respect to an axis perpendicular to the front surface. This design significantly promotes efficient chip flow and reduces the risk of chips getting stuck in the protective profile.

[0015] In another embodiment, the transition portion has an oval or elliptical cross-section perpendicular to the longitudinal extension of the transition portion, thereby making the transition portion particularly stable.

[0016] In this case, the transition portion may have an elliptical cross-section having semi-axis a and b, wherein the length of a is at least 120% of the length of b. Compared to conventional clamping bolts with a circular cross-section of radius b, the transition portion of the clamping bolt according to the invention has a significantly larger cross-sectional area and is therefore designed to be much more stable.

[0017] According to one aspect, the transition portion is curved, and the central longitudinal axis of the head portion extends at an angle greater than 0° relative to the central longitudinal axis of the clamping portion. In this case, the longitudinal extension of the transition portion extends along the curve of the transition portion. Due to the curvature of the transition portion, the head portion has a different orientation than the clamping portion. This allows the clamping bolts and associated fastening elements to be arranged in a particularly advantageous manner in the cutting tool, for example, in a way that facilitates the assembly of the cutting insert and / or the manufacture of the cutting tool.

[0018] In this case, the angle can be greater than 5°.

[0019] Furthermore, it can be specified that the rib has a longitudinal extension that runs parallel to the longitudinal extension of the clamping portion. This design has the advantage that the load is distributed particularly effectively on the longitudinal extension of the clamping portion through the rib.

[0020] According to one embodiment, the rib extends longitudinally toward the clamping surface. This means that its height is reduced. In this way, when the cutting insert is fastened to the cutting tool by means of clamping bolts and fastening elements, the rib can extend over a particularly large longitudinal section without obstructing the fastening elements from reaching the area traversed by the clamping surface.

[0021] Alternatively, the ribs may taper longitudinally toward one end facing the clamping surface to form a corresponding recess for fastening the element.

[0022] In another embodiment, the head portion and the clamping portion each have a rotationally symmetrical portion, and the head portion and the clamping portion are adjacent to a transition portion via the rotationally symmetrical portion. This makes the clamping bolt particularly material-saving.

[0023] According to the present invention, a cutting assembly having a cutting tool and a cutting insert is also provided to solve the problems mentioned above, wherein the cutting insert is fastened to the cutting tool by means of a clamping bolt having the advantages mentioned above according to the present invention. Attached Figure Description

[0024] Other advantages and features will emerge from the following description and accompanying drawings. (See attached drawings for details.)

[0025] Figure 1 Schematic cross-sectional view of a cutting assembly according to the invention, having clamping bolts according to the invention.

[0026] Figure 2 From Figure 1 Side view of the clamping bolt.

[0027] Figure 3 From Figure 1 A top view of the clamping bolts.

[0028] Figure 4 From Figure 3 A detailed view of the head portion of the clamping bolt.

[0029] Figure 5 Along Figure 2 The transition portion of the clamping bolt in the cross-sectional view of plane NN, and

[0030] Figure 6 From Figure 1 A three-dimensional view of the clamping bolts.

[0031] The following detailed description, taken in conjunction with the accompanying drawings, is intended as a description of various embodiments of the disclosed subject matter and is not intended to illustrate a single embodiment, wherein the same numerals refer to the same elements. Any embodiments described in this disclosure are used as examples or for illustrative purposes only and should not be construed as preferred or advantageous over other embodiments.

[0032] All features disclosed below in relation to exemplary embodiments and / or drawings may be combined individually or in any sub-combination with features of various aspects of this disclosure (including features of preferred embodiments), provided that the resulting combination of features is reasonable to those skilled in the art. Detailed Implementation

[0033] Figure 1 The cutting assembly 10 in an assembled state is shown. The cutting assembly includes a cutting tool 12, a cutting insert 14, and a clamping bolt 20.

[0034] Cutting tool 12 is, for example, a milling tool, such as a milling cutter.

[0035] The cutting insert 14 is arranged in the recess 22 of the cutting tool 12 and is fastened to the cutting tool 12 by means of the clamping bolt 20 and the fastening element 24.

[0036] The clamping bolt 20 extends along its longitudinal extension 26 from the first longitudinal end 28 to the opposite second longitudinal end 30.

[0037] The longitudinal extension 26 is formed by a curve with continuous curvature, extending from the first longitudinal end 28 through all centers of the cross-section of the clamping bolt 20 to the second longitudinal end 30. The cross-section is perpendicular to the longitudinal extension 26.

[0038] In addition, the clamping bolt 20 has: a head portion 32 disposed at a first longitudinal end 28; a clamping portion 34 disposed at a second longitudinal end 30; and a transition portion 36 connecting the head portion 32 to the clamping portion 34.

[0039] In the illustrated embodiment, the fastening element 24 is a screw screwed onto the cutting tool 12.

[0040] In principle, the fastening element 24 can have any design and can be connected to the cutting tool 12 in any adjustable manner.

[0041] In the assembled state, the head portion 32 is arranged in the through hole 38 of the cutting insert 14, while the clamping portion 34 extends into the receiving seat 40 in the cutting tool 12.

[0042] The fastening element 24 engages with the clamping surface 44 of the clamping portion 34 on the clamping bolt 20 at its axial end 42 and pre-tensions it.

[0043] In this way, the cutting insert 14 is clamped in the recess 22 by means of the clamping bolt 20, and thus fixed to the cutting tool 12.

[0044] In this context, the head portion 32 has an axial front surface 46 at the first longitudinal end 28, which forms part of the outer side 48 of the cutting assembly 10.

[0045] When the cutting assembly 10 is in operation, that is, when the workpiece is machined by the cutting assembly 10, the outer side 48 forms one side of the cutting assembly 10, through which chips can flow.

[0046] This applies to cooling lubricants if a cooling lubricant is used during the operation of cutting assembly 10.

[0047] The following text is for reference only. Figures 2 to 6 The design of clamping bolt 20 will be explained in more detail.

[0048] The head portion 32 has twelve protrusions 50 on the axial front surface 46 (see...) Figure 4 The protrusion and the seven recesses 52 together form the protective outline 54 of the head portion 32.

[0049] In an alternative embodiment, the protective contour 54 may have any number of protrusions 50 and / or recesses 52, but has at least two protrusions 50 or at least two recesses 52.

[0050] The protrusion 50 is formed, for example, by a circular ridge.

[0051] Notch 52 is, for example, a circular groove-shaped notch.

[0052] In principle, the protrusion 50 and the recess 52 can be designed according to their respective needs.

[0053] In the illustrated embodiment, the protrusion 50 is arranged in the outer annular edge region 56 of the axial front surface 46, while the notch 52 is arranged in the central region 58 of the axial front surface 46.

[0054] In this case, the protrusion 50 and the recess 52 are each arranged to be rotationally symmetrical about an axis 60 perpendicular to the axial front surface 46.

[0055] In an exemplary embodiment, axis 60 coincides with the central longitudinal axis 62 of the head portion 32.

[0056] In an alternative embodiment, the protrusion 50 and the recess 52 may each be arbitrarily arranged on the axial front surface 46, for example, each being rotationally symmetrical about any axis.

[0057] The clamping portion 34 has a lateral recess 64 (see Figure 2 The lateral recess is adjacent to the clamping surface 44 and has a reinforcing structure 66 in the form of a rib 68.

[0058] Rib 68 extends in the longitudinal direction L from end 70 facing transition portion 36 to end 72 facing clamping surface 44. This means that the longitudinal extension of rib 68 extends parallel to the longitudinal extension 26 of clamping portion 34.

[0059] In the illustrated embodiment, the radial height of the rib 68, measured relative to the central longitudinal axis 74 of the clamping portion 34, continuously decreases in the longitudinal direction L from the radial height H at the end 70 facing the transition portion 36 to the radial height h at the end 72 facing the clamping surface 44. In other words, the rib 68 tapers towards the clamping surface 44 in the longitudinal direction L (see [link to previous embodiment]). Figure 6 ).

[0060] In addition, the width of rib 68 (see Figure 3 The width D of the rib 68 continuously decreases from the end 70 facing the transition portion 36 to the width d of the end 72 facing the clamping surface 44 in the longitudinal direction L. In other words, the rib 68 tapers toward the clamping surface 44 in the longitudinal direction L.

[0061] In principle, rib 68 can be designed in any way.

[0062] In an alternative embodiment, the reinforcing structure 66 can be designed in any way, as long as it has ribs 68.

[0063] The transition portion 36 has an elliptical cross-section 76 in the section perpendicular to the longitudinal extension 26 (see...). Figure 5 The elliptical cross-section has a major semi-axis a and a minor semi-axis b.

[0064] The major semi-axis a has a length M, which is 125% of the length m of the minor semi-axis b.

[0065] Therefore, the cross-sectional area of ​​the elliptical cross section 76 (A=πab) is greater than the area of ​​the circle with radius b (A=πb). 2 ) 25% larger.

[0066] In principle, the length L of the major semi-axis a can be any multiple of the length m of the minor semi-axis b, for example, at least 1.2 times.

[0067] In an alternative embodiment, the transition portion 36 may have any non-circular cross-section 76 perpendicular to the longitudinal extension 26, such as an oval cross-section.

[0068] Furthermore, in the illustrated embodiment, the transition portion 36 is curved (see [reference]). Figure 2 Thus, the central longitudinal axis 62 of the head portion 32 extends at an angle α of 30° relative to the central longitudinal axis 74 of the clamping portion 34.

[0069] In principle, the angle α can have any value greater than 0°, such as any value greater than 5°.

[0070] Alternatively, the angle α can be 0°, and the transition portion 36 can be straight, i.e., not curved.

[0071] In this context, the transition portion 36 is adjacent to portion 78 of the head portion 32 on one hand and portion 80 of the clamping portion 34 on the other hand, the portions 78 and 80 being designed to be rotationally symmetrical with respect to the central longitudinal axes 62 and 72 of the head portion 32 and the clamping portion 34, respectively.

[0072] In this manner, a clamping bolt 20 and a cutting assembly 10 having the clamping bolt 20 are provided, the clamping bolt being designed to be particularly robust and have a long service life.

[0073]

Claims

1. A clamping bolt (20) for fastening a cutting insert (14) to a cutting tool (12), comprising: The clamping bolt (20) comprises a head portion (32) located at a first longitudinal end (28) of the clamping bolt (20); a clamping portion (34) located at a second longitudinal end (30) of the clamping bolt (20) opposite to the first longitudinal end (28) and having a clamping surface (44) as a mating surface for fastening the element (24); and a transition portion (36) connecting the head portion (32) to the clamping portion (34), wherein the clamping bolt (20) includes at least one of the following features: The head portion (32) has a protective profile (54) on the axial front surface (46) at the first longitudinal end (28), wherein the protective profile (54) has a plurality of protrusions (50) and / or a plurality of notches (52). The clamping portion (34) has a recess (64) and the recess has a reinforcing structure (66) including a rib (68). The transition portion (36) has a non-circular cross-section (76) of a longitudinal extension (26) perpendicular to the transition portion (36).

2. The clamping bolt (20) according to claim 1, wherein the protrusion (50) of the protective profile (54) is arranged in the edge region (56) of the front surface (46), and / or the notch (52) of the protective profile (54) is arranged in the central region (58) of the front surface (46).

3. The clamping bolt (20) according to claim 1 or 2, wherein the protrusion (50) of the protective profile (54) and / or the recess (52) of the protective profile (54) are arranged to be rotationally symmetrical with respect to an axis (60) perpendicular to the front surface (46).

4. The clamping bolt (20) according to any of the preceding claims, wherein the transition portion (36) has an oval or elliptical cross section (76) perpendicular to the longitudinal extension (26) of the transition portion (36).

5. The clamping bolt (20) according to claim 4, wherein the transition portion (36) has an elliptical cross-section (76) having semi-axis a and b, wherein the length of a is at least 120% of the length of b.

6. The clamping bolt (20) according to any one of the preceding claims, wherein the transition portion (36) is curved, and the central longitudinal axis (62) of the head portion (32) extends at an angle (α) greater than 0° relative to the central longitudinal axis (74) of the clamping portion (34).

7. The clamping bolt (20) according to any one of the preceding claims, wherein the rib (68) has a longitudinal extension that extends parallel to the longitudinal extension (26) of the clamping portion (34).

8. The clamping bolt (20) according to any one of the preceding claims, wherein the rib (68) extends toward the clamping surface (44) in the longitudinal direction (L).

9. The clamping bolt (20) according to any of the preceding claims, wherein the rib (68) tapers toward the end (72) facing the clamping surface (44) in the longitudinal direction (L).

10. The clamping bolt (20) according to any of the preceding claims, wherein the head portion (32) and the clamping portion (34) each have rotationally symmetrical portions (78, 80), the head portion and the clamping portion being adjacent to the transition portion (36) via the rotationally symmetrical portions.

11. A cutting assembly (10) having a cutting tool (12) and a cutting insert (14), the cutting insert being fastened to the cutting tool (12) by means of a clamping bolt (20) according to any one of the preceding claims.

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