Form cutter, use of a form cutter, method for machining a windshield and windshield

Abstract

Form milling cutter (10) for machining a windshield (12) for a motor vehicle, with a rotating tool body (16) and a cutting area (18) which has a semicircular central section (22) which transitions substantially tangentially at least at one end into a first transition section (24) of the cutting area (18), characterized in that the cutting area (18) is formed as a circumferential groove (20) in the tool body (16).

Description

[0001] The invention relates to a form milling cutter for machining a windshield for a motor vehicle, the use of a form milling cutter for machining a windshield, a method for machining a windshield and a windshield for a motor vehicle, in particular for a motorized two-wheeler.

[0002] Windshields are used on motorized two-wheelers such as scooters or motorcycles to reduce the wind force reaching the rider. Therefore, windshields are typically positioned in front of the rider, facing the direction of travel. Windshields are usually made of a transparent plastic, such as polycarbonate, using a deep-drawing process.

[0003] Due to regional and / or national regulations, such as the EU4 Directive, manufactured windshields must meet certain safety requirements. Therefore, among other things, the manufactured windshields must be subsequently machined to ensure that no sharp edges remain on the finished windshield.

[0004] For this purpose, it is known from the prior art to subsequently machine the windshields with a form cutter featuring a semicircular cutting area. The lateral edge of the windshield, i.e., the side area of ​​the windshield located between a windshield surface exposed to the airflow and an inner surface of the windshield facing the driver, is essentially smoothed by the milling process, so that no sharp edges remain, especially at the transition between the windshield surface and the side area.

[0005] However, the prior art machining method has proven disadvantageous in that the semicircular cutting area can lead to undefined machining of the windshield if the windshield is not machined precisely in the center by the form cutter. However, this is unavoidable due to manufacturing-related deviations, which is why the exact geometry of the reworked side area is random and cannot be precisely repeated.

[0006] US 4,669,923 A describes a form milling cutter with a rotating tool body and a cutting area. The cutting area has an arcuate section that transitions tangentially into two straight sections 13, 15.

[0007] US 3,718,958 A discloses a form milling cutter with a part-circular cutting profile. Guide surfaces are provided on both sides of the cutting area, which form an angle of 90° with each other and ensure stable guidance of the milling cutter during machining.

[0008] One object of the invention is to enable the processing of the windshield in a defined and repeatable manner. Furthermore, one object of the invention is to provide a windshield that can be manufactured in a defined and repeatable manner.

[0009] The object of the invention is achieved, among other things, by a form milling cutter for machining a windshield for a motor vehicle, comprising a rotating tool body and a cutting area having a partially circular central section that, at least at one end, transitions substantially tangentially into a first transition section of the cutting area. The cutting area is formed as a circumferential groove in the tool body.

[0010] Furthermore, the problem is solved by using such a form milling cutter for machining a windshield for a motor vehicle.

[0011] In addition, the object is achieved by a method for machining a windshield with a form milling cutter of the aforementioned type, wherein a side area of ​​the windshield is machined by the cutting area of ​​the form milling cutter.

[0012] Furthermore, the object of the invention is achieved by a windshield for a motor vehicle, in particular for a motorized two-wheeler, wherein the windshield has a windshield surface and an opposite inner surface which are connected to one another via a side region, wherein the side region has a part-circular side surface which has a radius greater than 2 mm, and a first transition surface which adjoins the side surface and merges into the windshield surface, and wherein the first transition surface encloses an obtuse angle with the windshield surface.

[0013] The basic idea of ​​the invention is to provide a transition surface in the side area of ​​the windshield to be machined, which allows for a higher error tolerance during machining of the windshield. This allows the side area of ​​the windshield to be machined in a defined and repeatable manner, even if the form milling cutter is not positioned exactly centrally to the windshield during machining of the windshield, as is theoretically intended. The obtuse angle between the first transition surface and the windshield surface is always maintained, even with relatively large deviations during machining. This is because the transition section in the cutting area is a straight line that essentially runs tangentially from the central section. Regardless of the machining, the same obtuse angle is always maintained between the windshield surface and the first transition surface, which is what is understood as repeatable machining.In contrast, the current state of the art offered very little tolerance for error, so machining the windshield with a milling cutter outside the center position quickly resulted in a visually noticeable step in the transition area. Depending on the machining of the windshield, this resulted in a different appearance.

[0014] The circumferential groove creates a form cutter that's easy to manufacture, as the cutting area is formed in the tool body itself, eliminating the need to attach additional cutting inserts to the tool body. This cutting area design is made possible, among other things, by the relatively soft material of the windshield, which is removed by the cutter.

[0015] In general, the partially circular central section has a predefined radius, which accordingly specifies the radius of the partially circular side surface of the windshield.

[0016] In particular, the obtuse angle between the first transition surface and the windshield surface is at least 150°, preferably more than 175°.

[0017] According to a particularly preferred embodiment, the first transition surface merges substantially tangentially into the windshield surface.

[0018] Here, “essentially tangential” means that deviations are tolerable that correspond to the deviations that cannot normally be avoided during production.

[0019] One aspect of the invention provides that the part-circular central section transitions essentially tangentially into a second transition section at the other end. This ensures that the transition between the part-circular side surface and the inner surface of the windshield is designed analogously to the transition from the side surface to the windshield surface. Therefore, there is no sharp-edged transition here either. Furthermore, the transition from the inner surface to the side area can also be manufactured with repeatable precision and precision.

[0020] The above-mentioned numerical values ​​or the tangential transition apply analogously to the transition between the inner surface of the windshield and the side area, in particular the second transition section.

[0021] According to a further aspect of the invention, the first and / or second transition section transitions into a first or second terminal section at the end opposite the central section. The terminal section represents the transition from the cutting area to a lateral surface of the tool body. The first terminal section can be formed by a part-circular section of the cutting area that has a defined radius. Under normal machining conditions, the first terminal section will not engage with the windshield, in particular the side area. Accordingly, the first terminal section is not to be regarded as an active part of the cutting area, which is why it is not important for machining the side area of ​​the windshield. This applies analogously to the second terminal section.

[0022] The cutting area can preferably be mirror-symmetrical to its center plane. Accordingly, the transition from the side area to the windshield surface is designed in a similar manner to the transition from the side area to the inner surface, or is removed in a similar manner during machining. The repeatable machining of the side area of ​​the windshield thus results in the transition area of ​​the windshield surface and the inner surface to the corresponding transition area.

[0023] One aspect of the invention provides that the side region of the windshield is designed to be substantially symmetrical with respect to its transitions. Accordingly, the first transition surface between the side surface and the windshield surface is designed analogously to a second transition surface of the windshield between the partially circular side surface and the inner surface of the windshield.

[0024] According to a further aspect of the invention, the side surface transitions tangentially into the first transition surface. The tangential transition between the side surface and the first transition surface is ensured by the tangential transition of the part-circular central section into the first transition section on the form cutter. The windshield therefore has no edge or step, so that the windshield meets the requirements of regional and / or national legislation.

[0025] Preferably, the windshield has been manufactured according to the above-mentioned method, in which a form milling cutter of the type described above has been used.

[0026] Due to the first and / or second transition surface, it is also ensured that the windshield can be formed with repeatable accuracy with the same specified obtuse angle between the transition surfaces and the windshield surface or the inner surface.

[0027] In general, the tangential transitions ensure repeatable and defined machining of the windshield with a significantly higher error tolerance when machining with the form milling cutter.

[0028] Further advantages and features of the invention will become apparent from the following description and the drawings, to which reference is made. In the drawings: - Fig. 1 a form milling cutter according to the invention during machining of a side area of ​​a windshield according to the invention, and - Fig. 2 the side area of ​​a windshield according to the invention.

[0029] In Fig. 1 shows a form milling cutter 10 which is used for machining a windshield 12, in particular for machining a side area 14 of the windshield 12, which is also shown in Fig. 1 is shown.

[0030] The form milling cutter 10 has a tool body 16 which rotates about a rotation axis R, provided that the tool body 16 is driven by a drive unit of the form milling cutter 10 (not shown here).

[0031] In addition, the form cutter 10 comprises a cutting area 18, which in the embodiment shown is formed as a circumferential groove 20 in the tool body 16 of the form cutter 10. Accordingly, the cutting area 18 is formed integrally with or in the tool body 16.

[0032] The cutting area 18 and the groove 20 are designed such that a part-circular central section 22 is provided, which at its two ends each merges substantially tangentially into a first transition section 24 and a second transition section 26.

[0033] At their ends facing away from the part-circular central section 22, the two transition sections 24, 26 each merge into a first end section 28 and a second end section 30, each of which is essentially part-circular in shape. The two end sections 28, 30 then merge into a lateral surface 32 of the tool body 16.

[0034] The two transition sections 24, 26 also essentially merge tangentially into the two final sections 28, 30.

[0035] The cutting area 18 is thus formed mirror-symmetrically to its center plane M, wherein the center plane M intersects the part-circular center section 22 centrally.

[0036] As from the Fig. 1, which shows how the form milling cutter 10 machines the side area 14 of the windshield 12 in the optimal case, when machining the windshield 12, both the part-circular central section 22 and the two transition sections 24, 26 are in engagement with the windshield 12, in particular its side area 14. In contrast, the two end sections 28, 30 do not engage with the windshield 12 and accordingly have no contribution to the active part of the cutting area 18.

[0037] A windshield 12 machined with the form cutter 10 is in Fig. 2 is partially shown, with only the processed side area 14 being shown.

[0038] The windshield 12 generally has a windshield surface 34, which, when mounted, is exposed to the airstream. Opposite the windshield surface 34, an inner surface 36 is provided on the windshield 12, which, when mounted, is directed toward the driver.

[0039] The side region 14 connects the windshield surface 34 and the inner surface 36, wherein the side region 14 has a part-circular side surface 38 with a radius greater than 2 mm and a first transition surface 40 extending from the side surface 38 to the windshield surface 34. Furthermore, a second transition surface 42 is provided, which extends between the part-circular side surface 38 and the inner surface 36. The two transition surfaces 40, 42 are linear or straight, i.e., without curvature.

[0040] In general, the windshield 12 has a substantially symmetrical shape in its side region 14, so that an axis of symmetry S is present. The axis of symmetry S intersects the partially circular side surface 38 essentially centrally.

[0041] Out of Fig. 1 shows that the axis of symmetry S of the windshield 12 coincides with the center plane M when the windshield 12 is optimally machined.

[0042] As from the Fig. 2, the part-circular side surface 38 merges essentially tangentially into the first transition surface 40 and essentially tangentially into the second transition surface 42.

[0043] The first transition surface 40 also forms an obtuse angle α with the windshield surface 34. The second transition surface 42 also forms an obtuse angle β with the inner surface 36.

[0044] If the windshield 12 is designed symmetrically in its side area 14, the two obtuse angles α, β are equal.

[0045] In general, the two angles α, β have a value of at least 150°, preferably more than 175°.

[0046] In a particularly preferred embodiment, the transition surfaces 40, 42 merge substantially tangentially into the windshield surface 34 and the inner surface 36, respectively.

[0047] The design of the form cutter 10 with its straight transition sections 24, 26 ensures that the two obtuse angles α, β are always constant. The tangential transitions between the part-circular central section 22 and the two transition sections 24, 26 thus ensure that greater process reliability is achieved when machining the side area 14, since the side area 14 can be manufactured with repeatable accuracy.

[0048] This is because, despite the unavoidable deviations during machining of the windshield 12, i.e. a deviation of the form cutter 10 from its optimal central position, no step is machined into the side region 14 of the windshield 12, as would be the case in the prior art.

[0049] According to the invention, even if the windshield 12 is machined off-center by the form cutter 10, it is ensured that no different angles are milled into the transition areas. This is due to the tangential transitions between the partially circular central section 22 and the linear transition sections 24, 26. Accordingly, the invention makes it possible for the windshield 12 to be manufactured with the same geometry with repeatable accuracy.

[0050] Repeatable machining means that the transitions between the transition surfaces 40, 42 and the windshield surface 34 or the inner surface 36 always have the same angle α, β, regardless of the relative axial alignment of the windshield 12 to the form milling cutter 10.

[0051] Furthermore, the transition sections 24, 26 ensure that the windshield 12 to be machined is oriented toward the center of the cutting area 18 during the machining process. The contour of the cutting area 18 thus features an automatic correction for the relative axial alignment of the form cutter 10 to the windshield 12, so that the side area 14 of the windshield 12 is or will be formed as symmetrically as possible.

[0052] All windshields 12 manufactured in this way therefore have a predefined transition from the windshield surface 34 and / or the inner surface 36 to the side area 14. Accordingly, the visual impression of the manufactured windshields 12 to the customer is always the same.

[0053] With the form milling cutter 10 according to the invention, its use in machining the windshield 12, and the method for machining the windshield 12, it is thus possible to manufacture a windshield 12 that always has the same, predefined transitions. In particular, these transitions can be manufactured with repeatable accuracy.

Claims

[1] Form milling cutter (10) for machining a windshield (12) for a motor vehicle, comprising a rotating tool body (16) and a cutting area (18) which has a part-circular central section (22) which, at least at one end, merges substantially tangentially into a first transition section (24) of the cutting area (18), characterized by that the cutting area (18) is designed as a circumferential groove (20) in the tool body (16). [2] Form milling cutter (10) according to claim 1, characterized by that the part-circular central section (22) merges at the other end substantially tangentially into a second transition section (26). [3] Form milling cutter (10) according to claim 1 or 2, characterized by that the first and / or second transition section (24, 26) merges into a first and / or second end section (28, 30) at the end opposite the central section (22). [4] Form milling cutter (10) according to one of the preceding claims, characterized by that the cutting area (18) is mirror-symmetrical to its center plane (M). [5] Use of a form milling cutter (10) according to one of the preceding claims for machining a windshield (12) for a motor vehicle. [6] Method for machining a windshield (12) with a form milling cutter (10) according to one of claims 1 to 4, wherein a side region (14) of the windshield (12) is machined by the cutting region (18) of the form milling cutter (10). [7] Windshield (12) for a motor vehicle, in particular a motorized two-wheeler, which has been produced by a method according to claim 6, which has a windshield surface (34) and an opposite inner surface (36) which are connected to one another via a side region (14), wherein the side region (14) has a part-circular side surface (38) which has a radius greater than 2 mm, and a first transition surface (40) which adjoins the side surface (38) and merges into the windshield surface (34), and wherein the first transition surface (40) encloses an obtuse angle (α) with the windshield surface (34). [8] Windshield (12) according to claim 7, characterized by that the side surface (38) merges tangentially into the first transition surface (40).

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