Grinding tool for internal cylindrical peel grinding

Abstract

Grinding tool (100) for internal cylindrical peel grinding, comprising • a cylindrical finishing zone area (120), and • a roughing zone area (110), wherein the roughing zone area (110) is frustoconical and / or conical and is arranged on the end face (121) of the cylindrical finishing zone area (120), wherein the grinding tool (100) is designed to be inserted into a workpiece bore (154) with the roughing zone area (110) leading during internal cylindrical peel grinding, • wherein the roughing zone area (110) and the finishing zone area (120) have a different material composition.

Description

State of the art

[0001] The present invention relates to a grinding tool for internal cylindrical peel grinding of a workpiece bore.

[0002] DE 23 36 705 C3 discloses a method for internal cylindrical peel grinding of workpiece bores using a cylindrical, rotating grinding wheel displaceable along its axis, wherein the grinding wheel has an inclined end face and a cylindrical section. DE 10 2014 203 402 B3 discloses a grinding machine and a method for grinding axial bores and workpieces with flat outer surfaces that can be machined on both sides. US 5 123 217 A discloses a drill for drilling hard and brittle materials comprising a shank and a drilling section attached to one end of the shank. Disclosure of the invention Advantages of the invention

[0003] The present invention relates to a grinding tool for internal cylindrical peel grinding of a workpiece bore. The grinding tool has a cylindrical finishing zone and a roughing zone. The roughing zone is frustoconical and / or conical and is arranged on the end face of the cylindrical finishing zone. The grinding tool is designed to be inserted into the workpiece bore with the roughing zone leading during internal cylindrical peel grinding. Advantageously, the grinding tool has a shank for this purpose, which is arranged on the finishing zone, and the grinding tool is designed to be held by the shank in a tool holder of a grinding machine and set in rotation. The grinding tool has a different material composition in the roughing zone and the finishing zone.This advantageously allows the two functions of the grinding tool to be optimized: material removal in the workpiece bore and fine grinding or smoothing of the workpiece bore. For example, material removal in the workpiece bore is increased, and wear on the grinding tool during its feed into the bore is reduced. Furthermore, the smoothing of the workpiece bore can be improved; that is, with the grinding tool of the present invention, a lower roughness of the workpiece bore can be achieved with the same or improved material removal.

[0004] In a preferred embodiment, the different material composition in the roughing zone and the finishing zone is characterized by the fact that the roughing zone has a larger abrasive grain size than the finishing zone. This offers the advantage that the larger abrasive grains in the roughing zone increase the cutting performance or material removal rate of the grinding tool in the workpiece bore, while the smaller abrasive grains in the finishing zone increase the smoothing of the workpiece bore.

[0005] In a further embodiment, the roughing zone has a first bonding matrix, in particular a metal and / or a ceramic, and the finishing zone has a second bonding matrix, in particular a synthetic resin and / or a metal and / or a ceramic. The first bonding matrix has a greater mechanical hardness than the second bonding matrix. This offers the advantage of increasing the cutting performance of the grinding tool and the fine grinding of the workpiece bore by means of the grinding tool, as well as reducing wear of the grinding tool.

[0006] In another embodiment, the porosity of the first bond matrix in the roughing zone is lower than the porosity of the second bond matrix in the finishing zone. This advantageously results in increased material removal rates of the grinding tool and improved smoothing of the workpiece bore, or reduced wear of the grinding tool.

[0007] In a further development, the roughing zone has a higher abrasive grain density than the finishing zone. This advantageously reduces, for example, wear of the grinding tool during operation.

[0008] Preferably, the roughing zone can have a first abrasive grain type, in particular a monocrystalline abrasive grain type, and the finishing zone can have a second abrasive grain type, wherein the second abrasive grain type is in particular a microcrystalline abrasive grain type. This advantageously results in sharper cutting edges being used in the roughing zone and creates a self-sharpening effect, thereby increasing or maintaining the machining performance. The microcrystalline abrasive grain in the finishing zone only fractures under higher pressure and is therefore tougher.

[0009] In another embodiment, the roughing zone area comprises a first abrasive grain material, in particular an abrasive grain made of cubic boron nitride (cBN) and / or diamond, and the finishing zone area comprises a second abrasive grain material, in particular an abrasive grain made of aluminum oxide and / or silicon carbide. By using different abrasive grain materials in the roughing and finishing zones, the cutting performance of the grinding tool and the smoothing of the workpiece bore can be increased, and the wear of the grinding tool can be reduced.

[0010] The invention also relates to an internal cylindrical peel grinding process comprising grinding a workpiece bore using a grinding tool according to the invention.

[0011] In a further development of the grinding process, the diameter of the grinding tool in the cylindrical finishing zone is smaller than the diameter of the workpiece bore. This advantageously reduces heat generation.

[0012] In a further embodiment of the grinding process, the grinding tool and the workpiece with its bore are rotated in opposite directions around parallel axes, with the rotation being generated by a grinding machine. Advantageously, the workpiece and the grinding tool are held in place by the grinding machine. This opposing rotation improves the smoothness of the inner surface of the workpiece bore.

[0013] Further advantages will result from the following description of exemplary embodiments with reference to the figures and from the dependent claims. Brief description of the drawings

[0014] The present invention is explained below with reference to preferred embodiments and accompanying drawings. Fig. 1: Grinding tool with different abrasive grain sizes in finishing and roughing zones Fig. 2: Grinding tool with different bonding matrices in finishing and roughing zones Fig. 3: Grinding tool with different abrasive grain densities in the finishing and roughing zones Fig. 4: Grinding tool with different abrasive grain shapes in finishing and roughing zones Fig. 5: Grinding tool with abrasive grains made of different abrasive grain materials in the finishing and roughing zones Embodiments of the invention

[0015] In Fig. Figure 1 shows a grinding tool 100 for internal cylindrical peel grinding when grinding a workpiece bore 154 of a workpiece 150. The workpiece 150 is held by a grinding machine (not shown) and is rotated counterclockwise around its axis of rotation 151 during operation. The grinding tool 100 is held by a tool holder (not shown) of the grinding machine (not shown) at a shank 130 and is rotated clockwise around its axis 101 and inserted or advanced into the workpiece bore 154 in the direction of the axis 101. See also a visualization of the feed direction in Figure 1. Fig. 1 through arrow 131. By means of a frustoconical roughing zone 110 of the grinding tool 100, the excess material 153 is first removed from the workpiece 150 in the workpiece bore 154 during the axial feed of the grinding tool 100 in the axial direction 131. By means of a further axial feed 131, the cylindrical finishing zone 120 of the grinding tool 100 smooths or finely grinds the cylindrical surface 152 of the workpiece 150 in the workpiece bore 154, thereby improving the roughness of the inner surface of the workpiece bore or the cylindrical surface 152 of the workpiece bore 154. In the roughing zone 110 of the grinding tool 100, first abrasive grains 102 with a first abrasive grain size are held or fixed by a first bonding matrix 104.The finishing zone 120 has a second abrasive grain size of the second abrasive grains 103, wherein the second abrasive grains 103 are held or fixed in the finishing zone 120 of the grinding tool 100 by a second bonding matrix 105. According to the invention, the grinding tool 100 has a different material composition in the roughing zone 110 and in the finishing zone 120. For example, as in the exemplary embodiment shown in . Fig. Figure 1 shows that the first abrasive grain size of the first abrasive grains 102 in the roughing zone 110 is larger than the second abrasive grain size of the second abrasive grains 103. By means of the larger abrasive grain sizes of the first abrasive grains 102, increased material removal of the workpiece interference 153 can be achieved in operation via the roughing zone 110. Furthermore, by means of the reduced abrasive grain size of the second abrasive grains 103 compared to the first abrasive grains 102, reduced roughness of the cylindrical surface 152 of the workpiece bore 154 can be achieved via the finishing zone 120. Accordingly, the grinding tool 100 according to the invention is made of Fig. 1 represents an improvement of existing grinding tools for internal cylindrical peel grinding, which have a uniform material composition in the roughing zone area 110 and in the finishing zone area 120.

[0016] In Fig. 2 is, as in Fig. Figure 1 shows a grinding tool 100 during internal cylindrical peel grinding of a workpiece bore 154. The grinding tool 100 is made of Fig. 2 has a first bonding matrix 104 in the roughing zone area 110, wherein the first bonding matrix 104 differs from the second bonding matrix 105 in the finishing zone area 120. For example, the first bonding matrix 104 and the second bonding matrix 105 comprise a metal and / or a ceramic and / or a synthetic resin, wherein in this embodiment the second bonding matrix 105 has a different composition, for example, the second bonding matrix 105 has a reduced mechanical hardness compared to the first bonding matrix 104. Accordingly, in this embodiment, the first bonding matrix 104 of the roughing zone area 104 is harder or stiffer than the second bonding matrix 105 of the finishing zone area 120, thereby increasing the machining performance or material removal by means of the roughing zone area 110 and the smoothing of the cylindrical surface 152 of the workpiece bore 154 by means of the finishing zone area 120.

[0017] In Fig. Figure 3 shows an alternative embodiment of the grinding tool 100. In the roughing zone area 110, there is a higher abrasive grain density 301 than in the finishing zone area 120 of the grinding tool 100.

[0018] Fig. Figure 4 shows a grinding tool 100, wherein, in contrast to a second abrasive grain type 402 of the second abrasive grains 103 in the finishing zone area 120, a more sharp-edged first abrasive grain type 401 of the first abrasive grains 102 is present in the roughing zone area 110. The monocrystalline abrasive grain type 401 of the first abrasive grains 102 supports the material removal in the roughing zone area 110 of the grinding tool 100 during operation, and the microcrystalline abrasive grain type 402 of the second abrasive grains 103, in contrast, increases the smoothing of the cylindrical surface 152 of the workpiece bore 154.

[0019] In Fig.Figure 5 shows first abrasive grains 102 made of a first abrasive grain material 501 in the roughing zone area 110 and second abrasive grains 103 made of a second abrasive grain material 502 in the finishing zone area 120. For example, the roughing zone area 110 has first abrasive grains 102 made of cubic boron nitride (cBN) as the first abrasive grain material 501 and the finishing zone area 120 has second abrasive grains 103 made of aluminum oxide as the second abrasive grain material 502.

Claims

[1] Grinding tool (100) for internal cylindrical peel grinding, comprising • a cylindrical finishing zone area (120), and • a roughing zone area (110), wherein the roughing zone area (110) is frustoconical and / or conical and is arranged on the end face (121) of the cylindrical finishing zone area (120), wherein the grinding tool (100) is designed to be inserted into a workpiece bore (154) with the roughing zone area (110) leading during internal cylindrical peel grinding, • wherein the roughing zone area (110) and the finishing zone area (120) have a different material composition. [2] Grinding tool (100) according to claim 1, characterized by , that • the roughing zone area (110) has a larger abrasive grain size than the finishing zone area (120). [3] Grinding tool (100) according to any one of the preceding claims, characterized by , that • the roughing zone area (110) has a first bonding matrix (104), in particular a metal and / or a ceramic, and the finishing zone area (120) has a second bonding matrix (105), in particular a synthetic resin, wherein the first bonding matrix (104) has a greater mechanical hardness than the second bonding matrix (105). [4] Grinding tool (100) according to any one of the preceding claims, characterized by , that • the porosity of a first bonding matrix (104) in the roughing zone area (110) is lower than the porosity of the second bonding matrix (105) in the finishing zone area (120). [5] Grinding tool (100) according to any one of the preceding claims, characterized by , that • the roughing zone area (110) has a higher abrasive grain density (301) than the finishing zone area (120). [6] Grinding tool (100) according to any one of the preceding claims, characterized by , that • the roughing zone area (110) has a first abrasive grain type, in particular a monocrystalline abrasive grain type, and the finishing zone area (120) has a second abrasive grain type, in particular a microcrystalline abrasive grain type. [7] Grinding tool (100) according to any one of the preceding claims, characterized by , that • first abrasive grains (102) of the roughing zone area (110) comprise a first abrasive grain material (501), in particular cubic boron nitride (cBN) and / or diamond, and second abrasive grains (103) of the finishing zone area (120) comprise a second abrasive grain material (502), in particular aluminum oxide and / or silicon carbide. [8] Internal cylindrical peel grinding process comprising grinding a workpiece bore (154) by means of a grinding tool (100) according to one of claims 1 to 7.

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