EP4260979A1 - Grinding device and method for grinding a workpiece - Google Patents

Abstract

Described and illustrated is a grinding device (1) for grinding a workpiece (3), in particular a brake disc, with a workpiece carrier (2) for carrying the workpiece (3) to be ground and with at least one grinding tool (5) for grinding at least one workpiece surface (4) to be ground of the workpiece (3) carried by the workpiece carrier (2). So that the grinding processing of workpieces can be carried out more cost-effectively, at least one regrinding tool (6) is provided for the grinding finishing of the at least one workpiece surface (4) that has been grinded by the grinding tool (5), at least partially at the same time as the grinding processing of the workpiece surface (4) to be ground Grinding tool (5) provided.

Description

The invention relates to a grinding device for grinding a workpiece, in particular a brake disc, with a workpiece carrier for carrying the workpiece to be ground and with at least one grinding tool for grinding at least one workpiece surface to be ground of the workpiece carried by the workpiece carrier. In addition, the invention relates to a method for grinding a workpiece, in particular a brake disc, with a grinding device, in particular of the type mentioned above.

Grinding devices are known in different designs, for example in the form of machine tools, and are used for the grinding processing of workpieces of different types. Regardless of the type of workpieces to be ground, grinding devices often have a workpiece carrier, for example in the form of a workpiece spindle, which holds the material to be ground Carries the workpiece during grinding. In addition, grinding devices typically have a grinding tool, for example in the form of a grinding wheel, with which the grinding processing of a workpiece surface to be ground of the workpiece carried by the workpiece carrier is carried out. Some grinding devices also have several grinding tools so that different workpiece surfaces of the workpiece can be grinded at the same time.

The demands placed on grinding in practice are increasing for many types of workpieces. For example, hard materials are increasingly being used as materials for many workpieces. For example, brake discs increasingly have a hard material coating in the area of their friction surfaces in order to reduce the abrasion that occurs on the brake disc during braking and thus the emitted To reduce the amount of fine dust. The use of hard materials leads to a significant increase in the processing time required for grinding, which ultimately results in increased costs.

Against this background, the present invention is based on the object of designing and developing the grinding device and the method of the type mentioned at the beginning and previously described in more detail in such a way that the grinding processing of workpieces can be carried out more cost-effectively.

This object is achieved in a grinding device according to the preamble of claim 1 in that at least one regrinding tool is provided for grinding post-processing of the at least one workpiece surface processed by the grinding tool, at least partially simultaneously with the grinding processing of the workpiece surface to be ground by the grinding tool.

• bei dem wenigstens eine zu schleifende Werkstückfläche des von einem Werkstückträger getragenen Werkstücks mit wenigstens einem Schleifwerkzeug schleifend bearbeitet wird,
• bei dem die wenigstens eine mit dem Schleifwerkzeug schleifend bearbeitete Werkstückfläche mit wenigstens einem Nachschleifwerkzeug schleifend nachbearbeitet wird und
• bei dem die schleifende Bearbeitung mit dem wenigstens einen Schleifwerkzeug und die schleifende Nachbearbeitung mit dem wenigstens einen Nachschleifwerkzeug wenigstens teilweise gleichzeitig erfolgen.

The stated object is further achieved according to claim 10 by a method for grinding a workpiece, in particular a brake disc, with a grinding device, in particular according to one of claims 1 to 9,

• in which at least one workpiece surface to be ground of the workpiece carried by a workpiece carrier is grinded with at least one grinding tool,
• in which the at least one workpiece surface machined with the grinding tool is reworked with at least one regrinding tool and
• in which the grinding processing with the at least one grinding tool and the grinding post-processing with the at least one regrinding tool take place at least partially simultaneously.

The grinding device therefore has at least one regrinding tool in addition to the at least one grinding tool. At least that's one Regrinding tool is designed to grind the workpiece surface processed by the grinding tool, at least partially simultaneously with the grinding processing of the workpiece surface to be ground by the grinding tool. By carrying out a grinding post-processing of the workpiece surface processed by the grinding tool with the regrinding tool at least partially simultaneously with the grinding processing of the workpiece surface to be ground with the grinding tool, the desired grinding result can be achieved in a significantly shorter time and the costs incurred for the grinding processing can therefore be reduced.

For example, in a short time, rough machining, often referred to as roughing, can be carried out using the grinding tool and fine machining, often also referred to as finishing, can be carried out on the workpiece surface using the regrinding tool. This offers the additional advantage that there is no need to change tools between rough machining and fine machining and therefore rough machining and fine machining can be carried out in one clamping. However, rough machining of the workpiece surface does not necessarily have to be carried out with the grinding tool and fine machining with the regrinding tool, although this may be preferred. For example, it can also be provided that rough machining of the workpiece surface is carried out with both the grinding tool and the regrinding tool, for example in order to achieve a relatively large amount of material removal in a short time.

Regardless of the type of grinding result to be achieved, particularly short processing times can be achieved if the grinding processing with the at least one grinding tool and the grinding post-processing with the at least one regrinding tool are carried out not only partially, but at least predominantly, in particular essentially, simultaneously.

The grinding device, which can be designed, for example, as a machine tool, can have a base, for example in the form of a machine bed. Then The base can carry the workpiece carrier, the at least one grinding tool and the at least one regrinding tool. In this way, a precise relative arrangement of the corresponding components to one another can be achieved, which can have a positive effect on the manufacturing tolerances that can be achieved. The workpiece carrier, the at least one grinding tool and the at least one regrinding tool can expediently be mounted on the base, for example directly or indirectly via at least one further component. Regardless of this, the base, in particular the machine bed, can at least predominantly, in particular at least essentially, be made of granite. Granite has good vibration-damping properties and is particularly temperature-stable, which has a positive effect on consistently high workpiece quality. Granite is preferably understood to mean natural granite, which can consist at least essentially of quartz, feldspars and mafic minerals, in particular mica.

The workpiece carrier, which can be designed, for example, as a workpiece spindle, is designed to carry the workpiece to be ground, in particular during grinding and/or post-processing. This contributes to simple and precise grinding. The workpiece carrier can expediently have at least one clamping device for clamping the workpiece. This means the workpiece can be easily and temporarily fixed to the workpiece carrier.

The at least one grinding tool and/or the at least one regrinding tool can be designed simply and expediently as a, in particular circular, grinding wheel. Regardless of this, the at least one grinding tool and/or the at least one regrinding tool can have a grinding surface for, in particular flat, grinding contact with the workpiece surface. Then the at least one grinding surface can be in grinding contact with the workpiece surface during the grinding processing and/or the grinding post-processing. Alternatively or additionally The at least one grinding surface can be arranged at least essentially in one plane. This can be particularly useful for flat workpiece surfaces in terms of simple and uniform grinding.

The workpiece, which can be part of the grinding device, can be made at least essentially of a metallic material, in particular cast iron or steel. With such materials, grinding can be particularly complex due to the typically relatively high hardness, so that the time advantages of simultaneous grinding and post-processing are particularly important. Against basically the same background, it can alternatively or additionally be advantageous if the workpiece has a coating, at least in the area of the at least one workpiece surface to be ground, which has a higher hardness than a core of the workpiece carrying the coating. The coating can then expediently be partially removed using the at least one grinding tool and/or the at least one regrinding tool. The coating can be made, for example, from cast iron, steel, aluminum oxide, carbon ceramic, tungsten carbide, silicon carbide, chromium carbide or niobium carbide. Aluminum oxide, carbon ceramic, tungsten carbide, silicon carbide, chromium carbide and niobium carbide enable particularly hard surfaces.

Regardless of the material, the workpiece can be at least essentially rotationally symmetrical. For rotationally symmetrical workpieces, simultaneous processing with the grinding tool and the regrinding tool can be easily achieved. Alternatively or additionally, the workpiece can be designed as a brake disc, in particular for a motor vehicle, such as a commercial vehicle and/or a passenger car. In practice, high demands are placed on the cycle times of corresponding workpieces, which is why the advantages of the invention are particularly important. Then the at least one workpiece surface to be ground can expediently be a friction surface of the brake disc.

For the sake of better understanding and to avoid unnecessary repetition, the grinding device and the method are described together below, without distinguishing in detail between the grinding device and the method. However, it is clear to the person skilled in the art based on the context which feature is particularly preferred with regard to the grinding device and/or the method.

According to a first particularly preferred embodiment of the grinding device, the workpiece carrier is rotatably mounted about a workpiece rotation axis. In this way, simultaneous grinding can be carried out by the grinding tool and the regrinding tool in a structurally simple manner. The grinding device can have a workpiece rotary drive for rotating the workpiece carrier around the workpiece rotation axis. This is not only useful in terms of the effort required for grinding, but can also contribute to a uniform grinding result.

Regardless of a rotatable mounting of the workpiece carrier, the at least one grinding tool can be rotatably mounted about a tool axis of rotation. This can have a positive effect on the grinding result and even wear on the grinding tool. For basically the same reasons, it can alternatively or additionally be advantageous if the at least one regrinding tool is mounted rotatably about a tool rotation axis. It can be advantageous in terms of design if the at least one tool axis of rotation is arranged at least substantially parallel to the workpiece axis of rotation. Alternatively or additionally, with a plurality of grinding tools and/or regrinding tools, it can be simple and expedient if the grinding tools and/or regrinding tools are rotatably mounted about the same tool axis of rotation.

For rotating the at least one grinding tool and/or the at least one regrinding tool around the, in particular respective, Tool rotation axis, the grinding device can have at least one tool rotation drive. This helps simplify grinding and can have a positive effect on uniform grinding results. It is fundamentally conceivable that the at least one grinding tool and the at least one regrinding tool are driven by the same tool rotary drive. Structurally and with regard to flexible grinding, however, it may be preferred if a tool rotary drive is assigned to the at least one grinding tool and the at least one regrinding tool.

In order to be able to move the at least one grinding tool along the workpiece surface, the grinding tool can be movable in a feed direction relative to the workpiece carrier. This can contribute to a simple realization of the simultaneous processing of the workpiece by the grinding tool and the regrinding tool. Against the same background, it can alternatively or additionally be advantageous if the at least one regrinding tool can be moved relative to the workpiece carrier for moving along the workpiece surface in a feed direction.

The feed direction of the at least one grinding tool can expediently be arranged at least substantially parallel to a grinding surface of the grinding tool. Alternatively or additionally, the feed direction of the at least one regrinding tool can expediently be arranged at least substantially parallel to a grinding surface of the regrinding tool. Regardless of this, the at least one feed direction can be arranged transversely, in particular at least substantially perpendicularly, to the workpiece rotation axis. This can be useful in terms of simple grinding for workpiece surfaces that are arranged at an angle to the workpiece axis of rotation, such as the friction surfaces of brake discs. Alternatively or additionally, the feed direction of the at least one regrinding tool can be arranged at least substantially parallel to the feed direction of the at least one grinding tool. This can in terms of an evenly distributed force input into the workpiece and therefore a high workpiece quality. Regardless of this, with a plurality of grinding tools and/or regrinding tools, it can be structurally simple if the grinding tools and/or regrinding tools are movable in the same feed direction.

In order to drive the at least one grinding tool and/or the at least one regrinding tool and to move it in the, in particular, respective feed direction, the grinding device can have at least one feed drive. This not only simplifies grinding, but can also contribute to an even grinding result. In principle, the at least one grinding tool and the at least one regrinding tool can be driven simply and cost-effectively by the same feed drive. With regard to flexible processing, however, it may be preferred if at least two feed drives are provided, one being assigned to the at least one grinding tool and the other to the at least one regrinding tool. Regardless of this, with a plurality of grinding tools and/or regrinding tools, it can be advantageous in terms of simple control and cost-effective design if the grinding tools and/or regrinding tools are driven by the same feed drive.

Basically, independently of a feed drive, the grinding device can have a, preferably electronic, control device. The control device can then be set up to move the at least one grinding tool and the at least one regrinding tool in relation to the respective distance from a workpiece carrier axis of the workpiece carrier at an offset to one another in the respective feed direction. The control device can therefore be set up to move the at least one grinding tool and the at least one regrinding tool in the respective feed direction in such a way that the grinding tool and the regrinding tool are in relation to the respective distance in the feed direction to the workpiece carrier axis are arranged at an offset from one another. In this way, successive grinding of the at least one workpiece surface can be carried out in a simple manner, first with the grinding tool and then with the regrinding tool. If the at least one feed drive is also provided, the control device can expediently be set up to control the at least one feed drive in such a way that the at least one grinding tool and the at least one regrinding tool are moved accordingly. Regardless of this, the offset can in particular mean a difference between the distance of the at least one grinding tool in the feed direction to the workpiece carrier axis and the distance of the at least one regrinding tool in the feed direction to the workpiece carrier axis. Alternatively or additionally, the workpiece carrier axis can expediently be the workpiece rotation axis.

With regard to a uniform grinding result, it may be advisable if the offset is at least essentially constant. Then the offset between the at least one grinding tool and the at least one regrinding tool can remain at least essentially unchanged while the grinding tool and the regrinding tool are moved in the respective feed direction. Regardless of whether the offset is constant or not, it may be advisable if the offset is smaller than the extension of the grinding tool, in particular a grinding surface of the grinding tool, in the feed direction. In this way, the size of the contact surface between the grinding tool and the workpiece and thus the forces acting on the grinding tool during grinding can be reduced. Against this background, it may also be advisable if the offset is at most 0.5 times the extent of the grinding tool, in particular the grinding surface of the grinding tool, in the feed direction. A particularly low force on the grinding tool can be achieved if the offset is at most 0.25 times, preferably at most 0.1 times, the extension of the Grinding tool, in particular the grinding surface of the grinding tool, in the feed direction.

Regardless of the relationship between the offset and the extension of the grinding tool, the offset can be at least 1 mm and/or at most 30 mm. On the one hand, it can be ensured that sufficient material removal is achieved with the grinding tool until the regrinding tool comes into grinding contact with the respective section of the workpiece surface, and on the other hand, short processing times can be ensured. Against this background, it can be particularly preferred if the offset is at least 2 mm, in particular at least 3 mm, and/or at most 20 mm, in particular at most 15 mm.

In order to adjust the material removal to be effected with the at least one grinding tool, the at least one grinding tool can be adjustable in an adjustment direction relative to the workpiece carrier. This means the material removal can be easily adjusted. For basically the same reason, it can alternatively or additionally be advantageous if the at least one regrinding tool is adjustable in an adjustment direction relative to the workpiece carrier in order to adjust the material removal to be effected with the regrinding tool. A flexible adjustment of the material removal is made possible if the at least one grinding tool and/or the at least one regrinding tool is adjustable in a pair of opposing adjustment directions. For the same reason, it can alternatively or additionally be provided that the at least one grinding tool and the at least one regrinding tool are independently adjustable in the respective setting direction. Regardless of this, the at least one adjustment direction can expediently be arranged at least substantially perpendicular to the feed direction of the at least one grinding tool and/or the at least one regrinding tool.

In order to drive the at least one grinding tool and/or the at least one regrinding tool and to adjust them in the, in particular respective, setting direction, the grinding device can have at least one actuator. This means that material removal can be adjusted particularly easily and precisely. The at least one grinding tool and the at least one regrinding tool can basically be driven by the same actuator. With regard to flexible adjustment of the tools independently of one another, however, it may be advisable if at least two actuators are provided, with the at least one grinding tool and the at least one regrinding tool each being assigned their own actuator.

The grinding device can have two grinding tools. The grinding tools can then be set up to grind two workpiece surfaces of the workpiece to be ground at least partially, in particular at least essentially, simultaneously. This means cycle times can be further reduced for workpieces with multiple workpiece surfaces to be ground. In addition, simultaneous grinding of the workpiece with two grinding tools can be advantageous in terms of the forces acting on the workpiece during grinding and thus the quality of the workpiece. For this reason, it can also be advantageous if the grinding tools are designed to grind workpiece surfaces that are at least essentially parallel and/or facing away from one another. Alternatively or additionally, for the reasons mentioned above, it may also be advisable if the grinding device has two regrinding tools. The regrinding tools can then be set up to at least partially, in particular at least substantially, simultaneously re-process the workpiece surfaces that have been ground by the grinding tools.

If two grinding tools are provided, the grinding tools, in particular grinding surfaces of the different grinding tools, can have a grinding gap limit on opposite sides. The workpiece can then be accommodated in sections in the grinding gap during grinding. This can also have an additional impact on the forces acting on the workpiece during grinding and have a positive effect on the workpiece quality. For the same reason, it can alternatively or additionally be advantageous if the regrinding tools, in particular grinding surfaces of the various regrinding tools, limit a grinding gap on opposite sides, so that the workpiece can be accommodated in sections in the grinding gap during the grinding post-processing.

In principle, the at least one grinding tool and the at least one regrinding tool can be designed in such a way that at least essentially the same surface quality can be achieved on the workpiece with the grinding tool and the regrinding tool. This can be useful, for example, if a large amount of material needs to be removed in a short period of time. However, it is particularly preferred if the at least one grinding tool is designed for rough machining of the workpiece surface and the at least one regrinding tool is designed for fine machining of the workpiece surface. This means that rough machining and fine machining of the workpiece surface can be carried out in one clamping operation. This not only enables particularly short processing times, but also prevents inaccuracies in processing that can result from re-clamping the workpiece and/or the tool.

For the sake of simplicity, the at least one grinding tool and the at least one regrinding tool can be designed at least essentially the same way. However, it can be particularly advantageous not only with regard to rough machining and subsequent fine machining if the at least one grinding tool and the at least one regrinding tool differ from one another with regard to the maximum grain size of the abrasive particles, the material of the abrasive particles and/or the material of the bond. This means that the grinding tool and the regrinding tool can be used for different grinding tasks be adjusted, which can have a positive effect on cycle times. The choice of the maximum grain size, the abrasive particle material and the bonding material depends in particular on the material to be processed, the required material removal and the required surface quality. Regardless of this, it may be advisable with regard to rough machining and subsequent fine machining if the maximum grain size of the abrasive particles of the regrinding tool is smaller than the maximum grain size of the abrasive particles of the grinding tool. The ratio of the maximum grain size of the abrasive particles of the regrinding tool to the maximum grain size of the abrasive particles of the grinding tool can expediently be between 0.1 and 0.7, preferably between 0.2 and 0.55, in particular between 0.3 and 0.45.

Regardless of a similar or different design of the grinding tool and the regrinding tool, the material for the abrasive particles of the at least one grinding tool and / or the at least one regrinding tool can be, for example, natural or synthetic diamond or cubic boron nitride. These materials have a particularly high hardness. Regardless of the material of the abrasive particles, the bond of the at least one grinding tool and/or the at least one regrinding tool can expediently be a metallic or ceramic bond.

Basically, the abrasive particles mean in particular the particles that cause the material to be removed from the workpiece. The bond serves in particular to hold the abrasive particles. For this purpose, the abrasive particles are preferably embedded in the bond at least in sections. Regardless of this, the abrasive particles of the at least one grinding tool and/or the abrasive particles of the at least one regrinding tool can expediently form a grinding surface of the grinding tool or the regrinding tool.

With regard to the forces acting on the workpiece during grinding and thus high workpiece quality, it can be advantageous if the at least one grinding tool and the at least one regrinding tool are arranged on opposite sides of the workpiece carrier, in particular on opposite sides of the workpiece rotation axis. Then the at least one grinding tool can be arranged on one side of the workpiece carrier and the at least one regrinding tool can be arranged on an opposite side of the workpiece carrier.

In a first particularly preferred embodiment of the method, the workpiece is rotated, in particular continuously, about a workpiece rotation axis during the grinding processing and/or during the grinding post-processing. The workpiece is therefore preferably rotated while the at least one grinding tool and/or the at least one regrinding tool is in grinding contact with the workpiece surface. In this way, it can be realized in a simple and cost-effective manner that at the same time a section of the workpiece surface that is to be ground is grinded with the grinding tool and a section of the workpiece surface that is ground with the grinding tool is reworked with the regrinding tool.

Alternatively or additionally, the at least one grinding tool can be rotated, in particular continuously, about a tool rotation axis during the grinding processing and/or the at least one regrinding tool during the grinding post-processing. Then the at least one grinding tool and/or the at least one regrinding tool can be rotated about the, in particular respective, tool axis of rotation, while the grinding tool and/or the regrinding tool is in grinding contact with the workpiece surface. This can contribute to a high quality of the grinding result and even wear of the grinding tool and/or the regrinding tool. Regardless, it can be constructively advantageous if the at least one tool axis of rotation is arranged at least substantially perpendicular to the workpiece surface.

Regardless of whether the grinding tool and/or the regrinding tool is rotated or not, the at least one grinding tool can be moved during the grinding processing and/or the at least one regrinding tool during the grinding post-processing, in particular continuously, in a feed direction along the workpiece surface. Then the at least one grinding tool and/or the at least one regrinding tool can be moved in the, in particular respective, feed direction while the grinding tool and/or the regrinding tool is in grinding contact with the workpiece surface. This can contribute to a simple realization of the simultaneous processing of the at least one workpiece surface by the grinding tool and the regrinding tool. For example, the at least one grinding tool and/or the at least one regrinding tool can be moved from a starting position assigned to one end of the workpiece surface in the feed direction to an end position assigned to another end of the workpiece surface. In this way, the entire workpiece surface can be successively grinded and/or reworked. Regardless of this, the at least one grinding tool and the at least one regrinding tool can expediently be moved at least partially simultaneously in the respective feed direction.

The at least one feed direction can expediently be arranged at least substantially parallel to the workpiece surface. Regardless of this, the feed direction of the at least one grinding tool can be arranged opposite to the feed direction of the at least one regrinding tool. This can have a positive effect on the forces acting on the workpiece during grinding and therefore on the workpiece quality and the service life of the workpiece carrier. Alternatively or additionally, at least one can For the sake of simplicity, the feed direction points in the direction of the workpiece rotation axis.

Regardless of the orientation of the at least one feed direction, it can be provided that the at least one grinding tool and the at least one regrinding tool are at an, in particular at least essentially constant, offset from one another in relation to the respective distance from a workpiece carrier axis of the workpiece carrier, in particular the workpiece rotation axis respective feed direction can be moved. Then the at least one grinding tool and the at least one regrinding tool can be moved in the respective feed direction in such a way that the grinding tool and the regrinding tool are arranged at an offset from one another in relation to the respective distance in the feed direction to the workpiece carrier axis. In this way, the at least one workpiece surface can be successively machined in a simple manner, first with the grinding tool and then re-machined with the regrinding tool, which can be particularly advantageous for rough machining and fine machining.

In order to reduce the forces acting on the grinding tool during grinding, it can be provided that a projection of the at least one grinding tool that is in grinding contact with the workpiece surface is arranged perpendicularly onto the workpiece surface at least in sections in a section of the workpiece surface that has been reworked with the regrinding tool . Then the projection of the grinding tool can be arranged in sections in the section that has been reworked with the regrinding tool, while the at least one workpiece surface is both machined with the grinding tool and refinished with the regrinding tool. Regardless of this, a particularly significant reduction in the forces acting on the grinding tool can be achieved if the projection of the grinding tool is at least over a predominant, in particular at least over a substantial, part of the width of the with Regrinding tool extends grinding reworked section of the workpiece surface. The width can in particular mean the extent of the relevant section in the feed direction of the grinding tool.

Alternatively or additionally, it can be provided that the at least one regrinding tool that is in grinding contact with the workpiece surface projects in the direction of the workpiece surface compared to the grinding tool that is in grinding contact with the workpiece surface. This not only enables effective grinding of the workpiece surface with the regrinding tool, but can also contribute to a reduction in the forces acting on the grinding tool during grinding. Then the at least one regrinding tool can protrude relative to the grinding tool in the direction of the workpiece surface, while the workpiece surface is both processed by grinding with the grinding tool train and refinished by grinding with the regrinding tool. Regardless of this, on the one hand it can be sufficient for the advantages mentioned and on the other hand it can be expedient in terms of processing technology if the at least one regrinding tool protrudes by 5 µm to 100 µm, preferably 10 µm to 70 µm, in particular 15 µm to 50 µm, relative to the grinding tool.

It can expediently be provided that a material removal to be effected with the at least one grinding tool and/or the at least one regrinding tool is adjusted. This can be done in a simple manner by adjusting the at least one grinding tool and/or the at least one regrinding tool in an adjustment direction, in particular relative to the workpiece carrier. A precise adjustment of the material removal can easily be made possible if the at least one adjustment direction is arranged at least substantially perpendicular to the workpiece surface. Alternatively or additionally, the material removal of the at least one grinding tool and/or the at least one regrinding tool can expediently be adjusted before the grinding process begins Grinding tool and/or grinding post-processing with the regrinding tool. Then the position of the at least one grinding tool during the grinding processing and/or of the at least one regrinding tool during the grinding post-processing can be at least essentially constant in the, in particular respective, setting direction. In this way, constant material removal across the workpiece surface can be achieved in a simple manner. Regardless of this, material removal is preferably understood to mean the thickness of the layer removed from the workpiece surface during grinding or grinding post-processing.

With regard to an additional reduction in cycle times and the forces acting on the workpiece during grinding, it may be advisable if two workpiece surfaces of the workpiece to be ground are at least partially, in particular at least essentially, processed simultaneously using two grinding tools. Then, against the same background, it can also be advisable if the workpiece surfaces that have been ground with the grinding tools are at least partially, in particular at least essentially, reworked at the same time with two regrinding tools. Regardless of this, it can also have a positive effect on the forces acting on the workpiece if the workpiece surfaces to be ground are arranged at least essentially parallel to one another and/or facing away from one another.

Fig. 1A-4B

eine erfindungsgemäße Schleifvorrichtung mit Schleifwerkzeugen und Nachschleifwerkzeugen der Schleifvorrichtung in verschiedenen Stellungen jeweils in einer Draufsicht und in einer Seitenansicht,

Fig. 5

ein Detail der Schleifvorrichtung aus den Fig. 1A-4B mit den Schleifwerkzeugen und Nachschleifwerkzeugen in der Stellung gemäß den Fig. 4A-B in einer Schnittansicht,

Fig. 6

ein Detail der Schleifvorrichtung aus den Fig. 1A-4B mit den Schleifwerkzeugen und Nachschleifwerkzeugen in der Stellung gemäß den Fig. 3A-B in einer Schnittansicht.

The invention is explained in more detail below using a drawing that only shows an exemplary embodiment. The drawing shows schematically:

Figs. 1A-4B

a grinding device according to the invention with grinding tools and regrinding tools of the grinding device in different positions, each in a top view and in a side view,

Fig. 5

a detail of the grinding device from the Figs. 1A-4B with the grinding tools and regrinding tools in the position according to Fig. 4A-B in a sectional view,

Fig. 6

a detail of the grinding device from the Figs. 1A-4B with the grinding tools and regrinding tools in the position according to Figs. 3A-B in a sectional view.

In the Fig. 1A-B a grinding device 1 is shown in a schematic top view and a schematic side view. The grinding device 1 has a workpiece carrier 2 in the form of a workpiece spindle. The workpiece carrier 2 carries a workpiece 3 in the form of a brake disc, for example for a commercial vehicle. In the present case, the workpiece 3 has two workpiece surfaces 4 to be ground, which in the illustrated and preferred exemplary embodiment are the friction surfaces of the brake disc. Depending on the number of workpiece surfaces 4 to be ground, the grinding device 1 in the present case has two grinding tools 5 and two regrinding tools 6, each of which is assigned to one of the workpiece surfaces 4. The grinding tools 5 and the regrinding tools 6 are arranged on opposite sides of the workpiece carrier 2.

The workpiece carrier 2 is rotatably mounted about a workpiece rotation axis DWS, which in the present case corresponds to the longitudinal axis AL of the workpiece carrier 2. The workpiece carrier 2 can thus be rotated together with the workpiece 3 about the workpiece rotation axis DWS. For rotating the workpiece carrier 2 about the workpiece rotation axis DWS, the grinding device 1 has a workpiece rotary drive, not shown, which can be designed, for example, as an electric or hydraulic drive.

The grinding tools 5 and the regrinding tools 6 are also rotatably mounted. In this case, the grinding tools 5 as well as the regrinding tools 6 can be rotated about a common tool axis of rotation DWZ stored. For rotating the grinding tools 5 and the regrinding tools 6, the grinding device 1 has four tool rotary drives (not shown), for example electrical or hydraulic, with each of the grinding tools 5 and the regrinding tools 6 being assigned one of the tool rotary drives.

The grinding tools 5 and regrinding tools 6, which are designed as circular grinding wheels in the illustrated and preferred exemplary embodiment, each have a grinding surface 7, 8 which is also circular in this case. The grinding tools 5 are arranged in such a way that the grinding surfaces 7 of the grinding tools 5 delimit a grinding gap 9 on opposite sides. In a similar manner, the grinding surfaces 8 of the regrinding tools 6 delimit a grinding gap 10 on opposite sides.

The grinding tools 5 and the regrinding tools 6 differ in the illustrated and therefore preferred exemplary embodiment with regard to their grinding particles forming the grinding surfaces 7, 8. The abrasive particles of the regrinding tools 6 are finer than the abrasive particles of the grinding tools 5. In the present case, the abrasive particles of the grinding tools 5 have a maximum grain size of approximately 400 μm. The abrasive particles of the regrinding tools 6 have a maximum grain size of approximately 150 μm. In this case, the abrasive particles of the grinding tools 5 are metallic and the abrasive particles of the regrinding tools 6 are ceramic-bonded.

In the Fig. 1A-B the grinding tools 5 and the regrinding tools 6 are shown in starting positions before the start of the grinding processing and the grinding post-processing. In order to adjust the material removal that is to be effected with the grinding tools 5 during grinding processing and with the regrinding tools 6 during the grinding finishing of the respective workpiece surface 4, the grinding tools 5 and the regrinding tools 6 can each be in a pair of opposing adjustment directions RE can be adjusted continuously. The setting directions RE are each arranged parallel to the tool rotation axis DWZ and perpendicular to the grinding surface 7, 8 of the respective grinding tool 5 or regrinding tool 6.

After the material removal to be effected has optionally been adjusted, the grinding tools 5 and the regrinding tools 6 are each moved towards the workpiece rotation axis DWS in a feed direction RV perpendicular to the respective adjustment direction RE. For this purpose, the grinding device 1 has two feed drives, not shown, designed as linear drives, one feed drive being assigned to the grinding tools 5 and the other feed drive being assigned to the regrinding tools 6. For example, the feed drives can each move a slide on which the grinding tools 5 or the regrinding tools 6 are mounted. The feed drives are controlled by an electronic control device (not shown) in such a way that the grinding tools 5 and the regrinding tools 6 are continuously moved in the respective feed direction RV. Meanwhile, the grinding tools 5 and the regrinding tools 6 are driven to rotate about the respective tool rotation axis DWZ and the workpiece carrier 2 together with the workpiece 3 about the workpiece rotation axis DWS, which can also be controlled by the control device, not shown.

In the Fig. 2A-B the grinding device 1 is shown in a schematic top view and a schematic side view. The grinding tools 5 are shown in positions shortly after the grinding tools 5 come into grinding contact with the assigned workpiece surface 4, and the regrinding tools 6 are shown in positions immediately before the regrinding tools 6 come into grinding contact with the assigned workpiece surface 4. Accordingly, the workpiece surfaces 4 each have a still unground and therefore to be ground section 11, which is arranged radially on the inside, and a section 12 which has already been ground by the respective grinding tool 5 and which is arranged radially on the outside.

The grinding tools 5 and the regrinding tools 6 are moved by the control device (not shown) in the respective feed direction RV in such a way that the grinding tools 5 and the regrinding tools 6 are arranged at an offset V to one another based on the respective distance to the workpiece rotation axis DWS. The offset V is set so that the distance between the grinding tools 5 and the workpiece rotation axis DWS is smaller than the distance between the regrinding tools 6 and the workpiece rotation axis DWS. In the present case, the offset V is significantly smaller than the extension of the grinding tools 5 in the feed direction RV and is approximately 0.5 cm to 1 cm. With the at least essentially constant offset V relative to one another, the grinding tools 5 and the regrinding tools 6 are moved continuously in the respective feed direction RV.

In the Figs. 3A-B the grinding device 1 is shown in a schematic top view and a schematic side view. The grinding tools 5 and the regrinding tools 6 are each in a position opposite the position according to Fig. 2A-B shown in the position moved further in the respective feed direction RV. Both the grinding tools 5 and the regrinding tools 6 are in grinding contact with the respective workpiece surface 4. Accordingly, the workpiece surfaces 4 each have a section 13 which is reworked by the respective regrinding tool 6 and which is arranged radially on the outside. The width of the sections 11 of the workpiece surfaces 4 to be ground is reduced and the sections 12 of the workpiece surfaces 4 that have been ground by the respective grinding tool 5 but have not yet been reworked by the respective regrinding tool 6 have migrated radially inwards. The projections of the grinding surfaces 7 of the grinding tools 5 extend in a direction perpendicular to the assigned workpiece surface 4 over the entire width B of the respective section 13 of the workpiece surface 4 that has been reworked by the regrinding tool 6.

In the Fig. 4A-B the grinding device 1 is shown in a schematic top view and a schematic side view. The grinding tools 5 are each shown in a position upon reaching the radially inner end of the respective workpiece surface 4 and the regrinding tools 6 are each shown in a position shortly before reaching the radially inner end of the respective workpiece surface 4. Accordingly, the sections 12 of the workpiece surfaces 4 that have been ground by the respective grinding tool 5 but have not yet been reworked by the respective regrinding tool 6 have migrated to the radially inner end of the respective workpiece surface 4. The width B of the sections 13 of the workpiece surface 4 reworked by the respective regrinding tool 6 is correspondingly increased. The workpiece surfaces 4 are completely ground by the respective grinding tool 5.

The regrinding tools 6 are moved further in the feed direction RV until they reach the radially inner end of the respective workpiece surface 4, in order to complete the grinding finishing of the workpiece surfaces 4. Then the grinding tools 5 and the regrinding tools 6 are each moved away from the associated workpiece surface 4 in a direction perpendicular to the respective feed direction RV and then back into the starting position according to Fig. 1A-B emotional. The finished ground workpiece 3 can then be removed from the workpiece carrier 2 and another workpiece 3 to be ground can be arranged on the workpiece carrier 2, whereupon the grinding process can begin again.

In the Fig. 5 is a detail of the grinding device 1 in the area of the workpiece carrier 2 in a sectional view along the in the Fig. 4A shown sectional plane VV. The grinding tools 5 and the regrinding tools 6 are in the position according to Fig. 4A-B shown. The brake pot 14 of the workpiece 3 designed as a brake disc rests on a support element 15 of the workpiece carrier 2. A centering mandrel 17 extends through the hub bore 16 of the brake disc of the workpiece carrier 2, over which the brake disc is clamped in the axial direction by means of a flange cover 18 and a bayonet lock 19 of the workpiece carrier 2.

In the Fig. 6 is a detail of the grinding device 1 in the area of the grinding tools 5 and the regrinding tools 6 in a sectional view along the in the Fig. 3A shown section plane VI-VI. The grinding tools 5 and the regrinding tools 6 are in the position according to Figs. 3A-B and, like the workpiece 3, shown partially cut. In the area of the workpiece surfaces 4, the workpiece 3 has a coating 20 which is applied to a core 21 of the workpiece 3 and whose thickness is shown significantly enlarged here. The coating 20 is designed as a hard material coating, for example made of aluminum oxide, carbon ceramic, tungsten carbide, silicon carbide, chromium carbide or niobium carbide, the hardness of which is higher than the hardness of the core 21 of the workpiece 3.

The grinding tools 5 and the regrinding tools 6 each remove part of the coating 20. In this case, the material removal MS caused by the grinding tools 5 is approximately 70 µm and the material removal MN caused by the regrinding tools 6 is approximately 30 µm, so that the total material removal in the present case is approximately 100 µm. The material removal MS,MN is shown significantly enlarged for the sake of clarity.

Reference symbol list

1

grinding device

2

Workpiece carrier

3

workpiece

4

workpiece surface

5

grinding tool

6

Regrinding tool

7

Grinding surface of a grinding tool

8th

Grinding surface of a regrinding tool

9

Grinding gap limited by grinding tools

10

Grinding gap limited by regrinding tools

11

section to be sanded

12

Section processed by a grinding tool

13

Section reworked by a regrinding tool

14

Brake pot

15

Support element

16

Hub bore

17

centering mandrel

18

flange cover

19

Bayonet fitting

20

Coating

21

core

AL

Longitudinal axis

b

Width

DWS

Workpiece rotation axis

DWZ

Tool rotation axis

MN

Material removal caused by a regrinding tool

MS

Material removal caused by a grinding tool

RE

Adjustment direction

RV

feed direction

v

offset

Claims (15)

Grinding device (1) for grinding a workpiece (3), in particular a brake disc, with a workpiece carrier (2) for carrying the workpiece (3) to be ground and with at least one grinding tool (5) for grinding at least one workpiece surface (4) to be ground ) of the workpiece (3) carried by the workpiece carrier (2),
characterized in that
at least one regrinding tool (6) is provided for the grinding post-processing of the at least one workpiece surface (4) processed by the grinding tool (5), at least partially simultaneously with the grinding processing of the workpiece surface (4) to be ground by the grinding tool (5). Grinding device according to claim 1,
characterized in that
the workpiece carrier (2) is rotatably mounted about a workpiece rotation axis (DWS) and/or that the at least one grinding tool (5) and/or the at least one regrinding tool (6) is at least substantially parallel, in particular to the workpiece rotation axis (DWS), Tool rotation axis (DWZ) is rotatably mounted. Grinding device according to claim 1 or 2,
characterized in that
the at least one grinding tool (5) and/or the at least one regrinding tool (6) for moving along the workpiece surface (4) in a, in particular to a grinding surface (7,8) of the grinding tool (5) and/or the Regrinding tool (6) can be moved relative to the workpiece carrier (2) in an at least substantially parallel feed direction (RV) and/or at least substantially perpendicular to the workpiece rotation axis (DWS). Grinding device according to claim 3,
characterized in that
a control device is set up, the at least one grinding tool (5) and the at least one regrinding tool (6) with respect to the respective distance to a workpiece carrier axis (AL) of the workpiece carrier (2), in particular the workpiece rotation axis (DWS), in an offset (V) to move relative to each other in the respective feed direction (RV) and that, preferably, the offset (V) is smaller than the extension of the grinding tool (5) in the feed direction (RV). Grinding device according to one of claims 1 to 4,
characterized in that
the at least one grinding tool (5) and/or the at least one regrinding tool (6) for adjusting the material removal (MS, MN) to be effected in an adjustment direction (RE) relative to the feed direction (RV), in particular at least substantially perpendicular to the feed direction (RV). Workpiece carrier (2) is adjustable. Grinding device according to one of claims 1 to 5,
characterized in that
two grinding tools (5) are provided for at least partially simultaneous grinding processing of two, in particular at least substantially parallel and/or facing away from each other, workpiece surfaces (4) of the workpiece (3) to be ground and that, preferably, two regrinding tools (6) for at least partially simultaneous grinding post-processing of the workpiece surfaces (4) that have been grinded by the grinding tools (5) are provided. Grinding device according to claim 6,
characterized in that
the grinding tools (5) and/or the regrinding tools (6) limit a grinding gap (9,10) for receiving the workpiece (3) in sections during the grinding processing and/or the grinding post-processing on opposite sides. Grinding device according to one of claims 1 to 7,
characterized in that
the at least one grinding tool (5) is designed for rough machining and the at least one regrinding tool (6) is designed for fine machining of the workpiece surface (4) and/or that the at least one grinding tool (5) and the at least one regrinding tool (6) differ in terms of the maximum grain size the abrasive particles, the material of the abrasive particles and/or the material of the bond differ from each other. Grinding device according to one of claims 1 to 8,
characterized in that
the at least one grinding tool (5) and the at least one regrinding tool (6) are arranged on opposite sides of the workpiece carrier (2). Method for grinding a workpiece (3), in particular a brake disc, with a grinding device (1), in particular according to one of claims 1 to 9, - in which at least one workpiece surface (4) to be ground of the workpiece (3) carried by a workpiece carrier (2) is grinded with at least one grinding tool (5), - in which the at least one workpiece surface (4) machined with the grinding tool (5) is reworked with at least one regrinding tool (6) and - in which the grinding processing with the at least one grinding tool (5) and the grinding post-processing with the at least one regrinding tool (6) take place at least partially simultaneously. Method according to claim 10, - in which the workpiece (3) is rotated about a workpiece rotation axis (DWS) during the grinding processing and/or the grinding post-processing and/or - in which the at least one grinding tool (5) is rotated during the grinding processing and/or the at least one regrinding tool (6) during the grinding post-processing about a tool axis of rotation (DWZ), in particular at least substantially perpendicular to the workpiece surface (4). Method according to claim 10 or 11, - in which the at least one grinding tool (5) is moved during the grinding processing and/or the at least one regrinding tool (6) during the grinding reworking in a feed direction (RV) along the workpiece surface (4) and - in which, preferably, the at least one grinding tool (5) and the at least one regrinding tool (6) are at an offset (V.) in relation to the respective distance from a workpiece carrier axis (AL) of the workpiece carrier (2), in particular the workpiece rotation axis (DWS). ) can be moved relative to each other in the respective feed direction (RV). Method according to one of claims 10 to 12, - in which a projection of the at least one grinding tool (5) in grinding contact with the workpiece surface (4) is perpendicular to the Workpiece surface (4) is arranged at least in sections in a section (13) of the workpiece surface (4) that has been reworked with the regrinding tool (6) and/or - in which the at least one regrinding tool (6), which is in grinding contact with the workpiece surface (4), projects in the direction of the workpiece surface (4) relative to the grinding tool (5) which is in grinding contact with the workpiece surface (4). Method according to one of claims 10 to 13, - in which, in particular before the start of the grinding processing and / or post-processing, material removal (MS, MN) to be effected with the at least one grinding tool (5) and / or the at least one regrinding tool (6) by adjusting the grinding tool (5) and / or the regrinding tool (6) is adjusted in an adjustment direction (RE), in particular at least substantially perpendicular to the workpiece surface (4). Method according to one of claims 10 to 14, - in which two, in particular at least essentially parallel and/or facing away from each other, workpiece surfaces (4) of the workpiece (3) to be ground are at least partially processed simultaneously using two grinding tools (5) and - in which, preferably, the workpiece surfaces (4) machined with the grinding tools (5) are at least partially re-machined simultaneously with two regrinding tools (6).

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