GRINDING MACHINE WITH A SWIVELLING TOOL SPINDLE

Abstract

Grinding machine (100) with a pivotable tool spindle (120) and with a workpiece spindle (110) which is designed to receive a gear workpiece (10) and to drive the gear workpiece (10) in rotation about a workpiece spindle axis (C), wherein the tool spindle (120) - is designed to receive a grinding tool (20) and to drive the grinding tool (20) in rotation about a tool spindle axis (B), - is supported by a pivot axis (A) such that the tool spindle (120) together with the grinding tool (20) can be pivoted about the pivot axis (A), - the swivel axis (A) is laterally offset from the workpiece spindle axis (C) and therefore the swivel axis (A) and the workpiece spindle axis (C) do not intersect, - wherein the grinding machine (100) comprises a shift axis (Sh) which is designed for transversely displacing the tool spindle (120) together with the grinding tool (20) in a vertical plane which is perpendicular to the pivot axis (A) and which is carried directly or indirectly by the pivot axis (A), wherein - the shift axis (Sh) together with the tool spindle (120) and the grinding tool (20) has a shifting center of mass (MP) which lies directly in the area of ​​the swivel axis (A).

Description

[0001] The present invention relates to grinding machines equipped with a pivoting tool spindle. Preferably, the grinding machines are equipped with a grinding worm for grinding gear workpieces. State of the art

[0002] Document EP 3 034 221 A1 discloses a grinding machine with a grinding tool for generating grinding two workpieces. Document DE 10 2009 023 275 A1 discloses a gear cutting machine for grinding external and / or internal profiles of workpieces. Document DE 19 66 577 A discloses a cradle of a gear cutting machine for producing gears using the generating process. Document CH 78 971 A discloses a method for producing spur and helical gears.

[0003] In Fig. Figure 1 shows a schematic view of a part of a grinding machine of the prior art. Fig. 1 shows a pivotable tool spindle 120 in a horizontal position. The tool spindle 120 here comprises a spindle housing 121 and a spindle motor which is concealed inside. A grinding worm 20 is attached to the tool spindle 120, which grinding worm can be driven in rotation about a tool spindle axis B by means of the spindle motor. In order to pivot the tool spindle 120, a pivot axis A is provided, which here is perpendicular to the plane of the drawing. Typically, such a grinding machine, which is equipped with a pivotable tool spindle 120, comprises a pivot plate which is in Fig. 1 is indicated by a dashed circle K. The swivel plate can be rotated in the plane of the drawing about the swivel axis A. The swivel axis A lies in the center of the circle K. The swiveling tool spindle 120 is arranged, for example, on a machine stand 101, which is indicated in the background of the Fig. 1 can be seen.

[0004] The workpiece to be ground is not in Fig. 1, but the position of the vertically extending workpiece spindle axis C is shown, which in the state of the art, ie in Fig. 1, intersects with the swivel axis A. The workpiece typically sits on a workpiece spindle (not shown) that can be rotated about the workpiece spindle axis C.

[0005] To absorb the uneven torques acting on the tool spindle 120 in this known configuration, the swivel plate, or rather the swivel axis A, can be mechanically clamped during grinding of the workpiece. In this case, the swivel axis A can essentially only be used as an adjustment axis. This means that the swivel axis A cannot be used dynamically, but only statically.

[0006] If the swivel axis A is to be used as a moving axis during grinding, mechanical clamping is not advisable. In this case, a drive motor is required that can hold the swivel axis A in position and also move it dynamically. The size of the drive motor depends on the torque to be applied. This temporary holding can be achieved, for example, by specifying a sufficiently large holding current for the drive motor used to swivel the swivel plate. However, specifying a holding current increases the power consumption of the grinding machine.

[0007] The task now is to provide a technical approach for operating a grinding machine that allows the swivel axis to be operated dynamically. Furthermore, the grinding machine should be economical to purchase and operate.

[0008] The object is achieved according to the invention by a grinding machine with a pivotable tool spindle according to claim 1. Advantageous embodiments of the invention form the subject matter of the dependent claims.

[0009] The invention is based on the approach of changing the overall configuration of the grinding machine so that the pivot axis, which serves to pivot the tool spindle, is arranged offset laterally relative to the workpiece spindle axis.

[0010] In addition, a configuration is selected in which the swivel axis for swiveling the tool spindle is located in the area of ​​the center of mass of the combination of tool spindle and tool.

[0011] Preferably, these two aspects are combined in all embodiments in such a way that the pivot axis is arranged laterally offset relative to the workpiece spindle axis and that the pivot axis lies in the area of ​​the center of mass of the combination of tool spindle and tool.

[0012] Preferably, embodiments in which the pivot axis directly or indirectly carries a shift axis have an asymmetric shift path of the shift axis.

[0013] The grinding machine of the invention comprises a pivotable tool spindle and is equipped with a workpiece spindle designed to hold a gear workpiece and to drive the gear workpiece in rotation about a workpiece spindle axis. The tool spindle is designed to hold a grinding tool and to drive the grinding tool in rotation about a tool spindle axis, and it is supported by a pivot axis such that the tool spindle, together with the grinding tool, can pivot about the pivot axis. In all embodiments, the pivot axis can directly or indirectly support a shift axis. However, embodiments that operate without an actual shift axis are also possible. In such embodiments, the shift movement parallel to the tool rotation axis is typically generated by the superimposed movement of other linear axes. In this case, the pivot axis is supported directly or indirectly by one or more linear axes.

[0014] The grinding machine of the invention is characterized in that the pivot axis is laterally offset relative to the workpiece spindle axis and therefore the pivot axis and the workpiece spindle axis do not intersect.

[0015] The fact that the swivel axis and the workpiece spindle axis do not intersect can also be expressed as follows: The swivel axis and the workpiece spindle axis intersect in 3-dimensional space, and they only intersect when the swivel axis is projected into the plane of the workpiece spindle axis.

[0016] Preferably, the tool spindle including the grinding tool has a center of mass located directly in the area of ​​the swivel axis. If the swivel mechanism of the swivel axis does not support a shift axis, the center of mass is a static point that is fixed relative to the tool spindle including the grinding tool. If the swivel mechanism of the swivel axis supports a shift axis, the center of mass is a point that can move depending on the shift position of the tool spindle including the grinding tool.

[0017] If the center of mass is located directly in the area of ​​the swivel axis, a balanced configuration of the tool spindle and tool results. A balanced configuration is defined as an arrangement in which the swivel axis is located exactly in the center of mass of the swivel device, including the tool spindle and grinding tool, or the swivel axis is located directly in the area of ​​the center of mass.

[0018] A key advantage of the invention is that the swivel axis drive can be smaller than before, since it only needs to compensate for smaller torques. The swivel axis drive can be designed smaller, which leads to improved energy efficiency of the machine.

[0019] A further advantage of the invention is that, due to the balanced configuration of the tool spindle and tool, no holding forces or lower holding forces are required to hold the swivel axis. The balanced configuration of the invention provides an additional degree of freedom, allowing swivel movements to be performed at any time, while the corresponding drive can be smaller than in previous solutions. The invention thus enables the transition from a previously static machining approach to a dynamic one.

[0020] The invention can be used, for example, in gear grinding machines.

[0021] The invention is particularly suitable for use in gear grinding machines designed for grinding straight and helical gears. This applies in particular to grinding machines designed for continuous generating or profile grinding.

[0022] The invention can be used primarily in gear grinding machines designed for grinding workpieces which are arranged in the gear grinding machine on a workpiece spindle with a vertical rotation axis and which comprise a tool spindle with a grinding tool (preferably with a grinding worm) which can be pivoted about a pivot axis perpendicular to the workpiece spindle axis.

[0023] A further advantage of the invention is that the machine width can be reduced if the tool spindle with the grinding tool is offset, for example, to the left. This is because the relatively long end of the grinding spindle, or rather the housing of the grinding spindle, protrudes less far beyond the slide of the shift axis.

[0024] In all embodiments, the shift axis is preferably arranged symmetrically to the workpiece spindle axis.

[0025] Preferably, the carriage width of the shift axis can be reduced in all embodiments.

[0026] The carriage width, or rather the shift path of the shift axis, can be asymmetrical in all designs.

[0027] The list of reference symbols is part of the disclosure. DRAWINGS

[0028] The figures are described in a coherent and comprehensive manner. Embodiments of the invention are described in more detail below with reference to the drawings. Fig. 1 shows a schematic front view of a tool spindle with grinding worm, as used in previously known grinding machines; Fig. 2A shows a schematic front view of a tool spindle with grinding worm, which according to a first embodiment of the invention is pivotally mounted with its center of mass directly in the region of a pivot axis and in which the workpiece spindle axis is laterally offset relative to the pivot axis; Fig. 2B shows a schematic front view of a tool spindle with grinding worm, which comprises a shift axis according to a second embodiment of the invention, wherein in the situation shown the tool spindle with grinding worm is located at a right end of the shift axis; Fig. Figure 2C shows a schematic front view of the second embodiment of the Fig. 2B, where in the situation shown the tool spindle with grinding worm is located approximately in the middle of the shift axis; Fig. Figure 2D shows a schematic front view of the second embodiment of the Fig. 2B, where in the situation shown the tool spindle with grinding worm is located at a left end of the shift axis; Fig. 3A shows a schematic front view of a tool spindle with a grinding worm, which includes a shift axis according to a third embodiment of the invention, wherein a gear workpiece is shown below the grinding worm; Fig. 3B shows a schematic front view of the tool spindle with grinding worm according to Fig. 3A, showing exemplary details of the shift axis; Fig. 4 shows a schematic front view of a grinding machine of the invention; Fig. Figure 5A shows a schematic diagram in which the torque of the swivel axis of a conventional machine configuration is plotted against the shift path of the shift axis; Fig. 5B shows a schematic diagram in which the torque of the swivel axis of a machine configuration according to the invention is plotted against the shift path of the shift axis. Detailed description

[0029] In connection with this description, terms are used that are also used in relevant publications and patents. However, it should be noted that the use of these terms is intended solely to facilitate understanding. The inventive concept and the scope of protection of the patent claims are not intended to be limited in interpretation by the specific choice of terms. The invention can be readily applied to other terminology systems and / or technical fields. In other technical fields, the terms are to be applied analogously.

[0030] Based on the above-described Fig. 1 it can be seen that the center of mass MP in previously known machines does not coincide with the point of passage of the swivel axis A. Since the spindle motor and the spindle housing 121 are relatively heavy, the center of mass MP, as shown in Fig. 1, e.g., to the right of the point of passage of the swivel axis A. In addition, the swivel axis A and the workpiece spindle axis C intersect.

[0031] The term center of mass MP, as used here, refers to the point at which the weight of those parts of the tool spindle 120, including tool 20, located to the right of the center of mass MP is equal to the weight of those parts of the tool spindle 120, including tool 20, located to the left of the center of mass MP. The center of mass MP is thus the mass-weighted average of the positions of all mass points of the tool spindle 120, including tool 20.

[0032] In other words, the tool spindle 120 together with the tool 20 is in a precisely balanced state if an axis is perpendicular to the plane of the drawing of the Fig. 1 through the center of mass MP and when the tool spindle 120 together with tool 20 remains in this position.

[0033] If a swivel table 122 is used as a swivel device, which carries a shift axis and a tool spindle 120 including tool 20, the center of mass MP is the mass-weighted mean of the positions of all mass points of the swivel table 122, the shift axis, the tool spindle 120 and the tool 20.

[0034] Based on the Fig. 2A, a first example of the invention will now be described using a first exemplary embodiment. In this first embodiment, the pivot axis A, or rather a pivot plate (not shown here) of the pivot axis A, carries only one tool spindle 120 and one tool 20.

[0035] Based on the Fig. 2A explains the two steps that led to the constellation according to the invention. In Fig. Figure 2A shows an exemplary configuration according to the invention, in which the pivot axis A passes through the tool spindle 120 including the tool 20 exactly at the center of mass MP. In this ideal case, the following statement applies: A=MP.

[0036] More generally, the passage of the pivot axis A can be located directly in the area of ​​the central center of mass in all designs. Therefore, the more general statement applies: A~MP.

[0037] Based on the Fig. 2A shows that with the balanced support of the tool spindle 120 including the tool 20, the position of the tool spindle 120 shifts relative to the position of the swivel table, or rather the swivel axis A. The position of the swivel table is indicated here by a dashed circle K - as in Fig. 1 - indicated.

[0038] Furthermore, the tool 20 should be positioned centrally relative to the workpiece 10 to be ground, so that all areas of the workpiece 10 can be easily reached and machined with the tool 20. Therefore, an axial offset ΔA2 is provided, as described below.

[0039] The offset between the conventional position of the tool spindle 120 in Fig. 1 and the new position of the tool spindle 120 in Fig. 2A is designated by the reference symbol ΔA1 and indicated by a block arrow. Fig. 1 and Fig. In the configurations shown in Figure 2A, the position of the machine stand 101 and the position of the swivel axis A including the swivel plate (indicated by the circle K) have remained the same. Fig. 2A, only the tool spindle 120 and tool 20 were shifted to the left relative to the position of the swivel axis A by ΔA1, and the position of the workpiece spindle axis C was shifted to the left by ΔA2. The shifting of the workpiece spindle axis C relative to the position of the swivel axis A is described below. ΔA1 can be equal to ΔA2 in all embodiments. However, ΔA1 and ΔA2 can also have different values ​​in all embodiments.

[0040] Instead of choosing an overall configuration in which the swivel axis A and the workpiece spindle axis C continue to intersect (as in Fig. 2A), according to the invention the workpiece spindle axis C is assigned a different position compared to the swivel axis A.

[0041] According to the invention, in all embodiments, an overall configuration is provided in which the pivot axis A has a lateral offset ΔA2 relative to the workpiece spindle axis C, as in Fig. 2A and in Fig. 3A is clearly visible. In the Fig. 2A to 2D and in Fig. 3A clearly shows that the swivel axis A and the workpiece spindle axis C cross but do not intersect. This statement applies to designs with a shift axis Sh, which carries a swivel axis A, primarily in a home or zero position. Depending on the shift path Shw of the shift axis Sh, the corresponding machine can temporarily assume a position in which the swivel axis A and the workpiece spindle axis C intersect.

[0042] However, the swivel axis A and the workpiece spindle axis C always intersect in a common plane projection. This plane projection is perpendicular to the drawing plane. The corresponding plane can, for example, be the plane in which the workpiece spindle axis C lies.

[0043] Preferably, in all embodiments, the swivel axis A runs in the said plane projection perpendicular to the workpiece spindle axis C, as can be seen from the Fig. 2A to 2D, 3A and Fig. 4. In all embodiments, these two axes A and C can run in a common plane projection or at an angle to each other.

[0044] In order to enable grinding of a gear workpiece 10 (in Fig. 3A shows an example of a straight-toothed spur gear workpiece 10), the grinding machine 100 must be designed to perform several movements in 3-dimensional space in a controlled manner.

[0045] Therefore, in all embodiments, a shift axis Sh is preferably used, which is designed for the transverse displacement of the tool spindle 120 together with the grinding tool 20 in a vertical plane that is perpendicular to the pivot axis A. The transverse displacement takes place along a shift path Shw. The said vertical plane runs in the representations of the Fig. 2A - 2D, 3A, 3B and 4 parallel to the plane of the drawing.

[0046] In the Fig. 2B - 2D, a linear slide 124 of the shift axis can be seen in three different shift positions. In Fig. 3A also shows a linear slide 124. In Fig. 3B shows details of an example shift axis Sh. In the Fig. 2B - 2D, 3A and 3B as well as in Fig. In the embodiments shown in Figure 4, the shift axis Sh sits on a pivot plate 122, which is rotatably mounted about the pivot axis A. The pivot plate 122 is preferably concentric with the pivot axis A in all embodiments.

[0047] The shift axis Sh is preferably designed in all embodiments as a linear slide 124, which may, for example, comprise two linear guides 123, as in Fig. 3B. Details of a shift axis Sh and such linear slides 124 are well known, and therefore no further details are provided here.

[0048] In addition to the transverse displacement along the shift path Shw, which is enabled here by the shift axis Sh, further controlled movements in 3-dimensional space are typically required. These essentially involve relative movements of the grinding tool 20 with respect to the gear workpiece 10. It is irrelevant for the invention whether, for example, the grinding tool 20 is moved and the gear workpiece 10 is only driven in rotation about the workpiece spindle axis C, or whether, for example, the gear workpiece 10 can also perform (linear) movements.

[0049] In Fig. 4 shows a preferred configuration of a grinding machine 100 of the invention. As already described, the grinding machine 100 of the invention comprises a tool spindle 120, which in all embodiments is preferably arranged relative to the pivot axis A such that the pivot axis A penetrates the tool spindle 120 directly in the region of the center of mass MP. In any case, the pivot axis A has a relative lateral offset from the position of the workpiece spindle axis C. As already mentioned, a pivot plate 122 carrying a linear slide 124 can be used in all embodiments. The linear slide 124 is part of the shift axis Sh.

[0050] In addition, in all embodiments, the grinding machine 100 of the invention can have three further axes X, Y, Z, which are designed as linear axes.

[0051] A first of these additional axes, referred to here as the Y-axis, extends in the example shown parallel to the workpiece spindle axis C, as in Fig. 4. This Y-axis can be arranged, for example, on a machine stand 101 of the grinding machine 100. In Fig. 4 shows that the Y-axis can, for example, comprise two linear guides 102. The Y-axis on the machine stand 101 carries the swivel axis A, and the swivel axis A, in turn, carries the shift axis Sh as well as the tool spindle 120 including the tool 20. Details of such a Y-linear axis are well known, and therefore no further details are provided here.

[0052] The Y-axis is used to perform a stroke (grinding stroke parallel to the C-axis). The Y-axis can be used in all versions, as shown in Fig. 4, be integrated into the machine stand 101, which also supports the tool spindle 120. However, in all embodiments, the Y-axis can also be arranged in the area of ​​the workpiece spindle 110 in order to be able to move the workpiece spindle 110 together with the gear workpiece 10 parallel to the C-axis.

[0053] A second of these additional axes, referred to here as the Z-axis, extends parallel to the swivel axis A. When displaying the Fig. 4, the corresponding Z-axis is perpendicular to the plane of the drawing. This Z-axis can, for example, enable a radial feed movement of the column 101 relative to the gear workpiece 10. In Fig. 4 shows that the Z-axis can comprise, for example, two linear guides 103. Details of such a Z-linear axis are well known, and therefore no further details are provided here.

[0054] The X-axis of such a grinding machine 100 can run parallel to the drawing plane. In the snapshot shown, the tool spindle axis B is parallel to the X-axis. If the shift axis Sh, as in Fig. 4, is located on the swivel plate 122, then the X-axis is not absolutely necessary. The linear movement parallel to the X-axis can be realized, for example, by the linear movement of the workpiece spindle 110 or by the linear movement of the column 101 relative to the workpiece spindle 110. Such arrangements are also well known.

[0055] The three further axes X, Y, Z preferably form a Cartesian coordinate system in all embodiments, as in Fig. 4 shown.

[0056] Depending on the embodiment, the pivot axis A, or the pivot plate 122, can carry several components. In the embodiments according to Fig. 2B to 2D, 3A, 3B and after Fig. 4, the swivel plate 122 carries, for example, the components of the shift axis Sh and the tool spindle 120 including tool 20. In this case, care is taken to ensure that the specification of the exactly balanced arrangement or the almost balanced arrangement of the swivel axis A includes all components that are carried by the swivel plate 122. This means that when determining the center of mass MP, the components of the shift axis Sh are also taken into account. Since the tool spindle 120 including tool 20 can be moved along the shift axis Sh, the center of mass MP also shifts. This is explained below using the Fig. 2B to 2D explained.

[0057] Fig. Figure 2B shows a schematic front view of a tool spindle 120 with grinding worm 20, which according to this second embodiment of the invention comprises a shift axis Sh. In the situation shown, the tool spindle 120 with grinding worm 20 is located at a right end of the shift axis Sh. The arrow labeled Sh in Fig. 2B shows that the tool spindle 120 with grinding worm 20 can only be moved to the left from this end position when the shift axis Sh is actuated.

[0058] Fig. Figure 2C again shows the second embodiment of the invention. In the situation shown, the tool spindle 120 with grinding worm 20 is located approximately in the center of the shift axis Sh. The double arrow marked Sh in Fig. 2C shows that the tool spindle 120 with grinding worm 20 can be moved to the right and to the left from this central position when the shift axis Sh is actuated.

[0059] Fig. Figure 2D also shows the second embodiment of the invention. In the situation shown, the tool spindle 120 with grinding worm 20 is located at a left end of the shift axis Sh. The arrow marked Sh in Fig. 2D shows that the tool spindle 120 with grinding worm 20 can only be moved to the right from this end position when the shift axis Sh is actuated.

[0060] When comparing the Fig. 2B to 2D it can be seen that the center of mass MP shifts when the tool spindle 120 is moved along with the tool 20. In Fig. 2B the center of mass MP is located to the right of the passage of the pivot axis A. In Fig. 2C the center of mass MP is located very close to the passage of the pivot axis A and in Fig. In 2D, the center of mass MP is located to the left of the passage of the pivot axis A. The center of mass MP does not necessarily shift symmetrically to the passage of the pivot axis A. In practice, there is usually an area for the shift of the center of mass MP that is asymmetric to the pivot axis A.

[0061] However, if the axis Sh (in this case, the axis Sh is not a shift axis in the true sense, but a linear axis) carries the swivel plate 122 together with the tool spindle 120 and tool 20, the components of this axis Sh do not need to be taken into account when determining the center of mass MP. The corresponding center of mass MP is also referred to as the static center of mass MP. Fig. Figure 2A shows an embodiment with a static center of mass MP.

[0062] In embodiments with a static center of mass MP, it may be advantageous to combine the passage of the pivot axis A with the center of mass MP when designing the machine 100, as already described. In embodiments with a shifting center of mass MP, it may be advantageous to place the passage of the pivot axis A in the displacement range of the center of mass MP when designing the machine 100, as described in the Fig. 2B to 2D.

[0063] Since the pivot axis A does not intersect with the workpiece spindle axis C according to the invention (except possibly in the aforementioned temporary special case), a certain asymmetry of the tool spindle 120, or of the tool 20, results relative to the workpiece spindle axis C. This asymmetry can be compensated for in all embodiments by the shift axis Sh being designed for the asymmetric transverse displacement of the tool spindle 120 together with the grinding tool 20 with respect to the pivot axis A. While the shift axis Sh in one embodiment of the prior art enabled movements of ± 150 mm, for example, the shift axis Sh in embodiments of the invention can enable a movement of + 150 mm to the left and a movement of - 120 mm to the right. These are merely numerical examples.

[0064] Due to the balanced arrangement, the holding means can be smaller in size, since smaller torques have to be compensated.

[0065] In order to graphically illustrate the effect of the invention, the Fig. 5A and Fig. 5B the numerical examples of a conventional machine configuration are compared with the numerical examples of a machine configuration according to the invention. Fig. Figure 5A shows a schematic diagram in which the torque DM of the swivel axis A of a conventional machine configuration (e.g. as in Fig. 1) is plotted against the shift travel Shw of the shift axis Sh. Due to the unbalanced configuration, the drive motor of the swivel axis A must be able to generate torques DM in the range of 1000 Nm to -200 Nm, i.e., the drive motor must be dimensioned to generate a maximum of 1000 Nm.

[0066] In Fig. 5B is a corresponding schematic diagram of a machine configuration according to the invention (e.g. as in Fig. 4) is plotted against the shift travel Shw of the shift axis Sh. Due to the significantly better balanced configuration, the drive motor of the swivel axis A only needs to be able to generate torques DM in the range of 700 Nm to -500 Nm, i.e., the drive motor must be dimensioned to generate a maximum of 700 Nm.

[0067] In an ideally balanced configuration, the values ​​of the positive and negative torque DM are equal. In order to achieve similar numerical values ​​as in the Fig. 5A and Fig. 5B, the torque of an ideally balanced configuration could be ±600 Nm, ie the drive motor must be dimensioned so that it can generate a maximum of 600 Nm.

[0068] The quality of balancing can thus be defined, for example, via the torque values. The smaller the absolute difference ΔDM between the torque values, the better the configuration is balanced. At ΔDM=0, the configuration is ideally balanced.

[0069] According to the invention, the center of mass MP is located directly in the area of ​​the pivot axis A if at least one of the following conditions is fulfilled (the numbers in brackets refer to the numerical example of the Fig. 5B): B1. if the smaller value of the negative and positive torque (500 Nm is less than 700 Nm) deviates by less than 30% from the larger value (here 700 Nm). In the example of the Fig. 5B, the 500 Nm is approximately 71.43% of the 700 Nm. The smaller value therefore deviates by less than 30% from the larger value and condition B1 is considered to be fulfilled. In the example of the Fig. 5A these values ​​differ by 80% and condition B1 is far from being met. B2. if the difference (700 Nm - 500 Nm = 200 Nm) of the absolute value of the positive torque (700 Nm) and the absolute value of the negative torque (|-500 Nm| = 500 Nm) deviates by less than 20% from the sum (700 Nm + 500 Nm = 1200 Nm) of the absolute value of the negative torque (|-500 Nm|= 500 Nm) and the absolute value of the positive torque (700 Nm). In the embodiment of the Fig. 5B, this definition results in a value of approximately 16.67%. Since 16.67% is smaller than 20%, in the case of Fig. 5B, condition B2 is fulfilled. In the embodiment of the Fig. 5A, this definition results in a value of approximately 66.67% and condition B2 is far from being met. B3. If, in a diagram in which the torque DM of the swivel axis A is plotted against the shift path Shw of the shift axis Sh, the curve of the torque DM is symmetrical to the axis that represents the shift path Shw, then condition B3 is considered to be fulfilled. B4. If, in a diagram in which the torque DM of the swivel axis A is plotted against the shift path Shw of the shift axis Sh, the course of the shift path Shw is symmetrical to the axis that represents the torque DM, then condition B4 is considered to be fulfilled.

[0070] Conditions B1 and / or B2 are preferably applied to constellations where the swivel axis A does not carry a shift axis Sh (see e.g. Fig. 2A).

[0071] Conditions B2 and / or B3 and / or B4 are preferably applied to constellations where the swivel axis A carries a shift axis Sh (see e.g. Fig. 2B - 2D, 3A, 3B, 4).

[0072] Based on the Fig.5B shows, for example, that the shift axis Sh can be designed for asymmetric transverse displacement of the tool spindle 120 including the grinding tool 20 with respect to the pivot axis A. The shift path Shw extends significantly further into the negative range than into the positive range of the graphic (i.e., the shift axis Sh allows larger movements to the left than to the right). List of reference symbols 10 Gear workpiece 20 grinding tools 100 grinding machine 101 stands 102 linear guides 103 linear guides 110 Workpiece spindle 120 tool spindle 121 spindle housing 122 swivel plates 123 linear guides 124 linear slides of the shift axis A swivel axis B Tool spindle axis B1, B2, B3, B4 conditions C Workpiece spindle axis DM torque ΔA1 offset ΔA2 axis offset MP center of mass K Circle Sh shift axle Shw Shiftweg X, Y, Z axes

Claims

[1] Grinding machine (100) with a pivotable tool spindle (120) and with a workpiece spindle (110) which is designed to receive a gear workpiece (10) and to drive the gear workpiece (10) in rotation about a workpiece spindle axis (C), wherein the tool spindle (120) - is designed to receive a grinding tool (20) and to drive the grinding tool (20) in rotation about a tool spindle axis (B), - is supported by a pivot axis (A) such that the tool spindle (120) together with the grinding tool (20) can be pivoted about the pivot axis (A), - the swivel axis (A) is laterally offset from the workpiece spindle axis (C) and therefore the swivel axis (A) and the workpiece spindle axis (C) do not intersect, - wherein the grinding machine (100) comprises a shift axis (Sh) which is designed for transversely displacing the tool spindle (120) together with the grinding tool (20) in a vertical plane which is perpendicular to the pivot axis (A) and which is carried directly or indirectly by the pivot axis (A), wherein - the shift axis (Sh) together with the tool spindle (120) and the grinding tool (20) has a shifting center of mass (MP) which lies directly in the area of ​​the swivel axis (A). [2] Grinding machine (100) according to claim 1, characterized by that the center of mass (MP) is displaceable in a region around the pivot axis (A), whereby this region can be symmetrical or asymmetrical. [3] Grinding machine (100) according to claim 1, characterized by that the center of mass (MP) shifts depending on a shift position of the shift axis (Sh). [4] Grinding machine (100) according to one of claims 1 to 3, characterized bythat the shift axis (Sh) is designed for asymmetric transverse displacement of the tool spindle (120) including the grinding tool (20) in relation to the swivel axis (A). [5] Grinding machine (100) according to one of claims 1 to 4, characterized by that the swivel axis (A) is not equipped with any means for clamping the tool spindle (120), since the tool spindle (120) together with the grinding tool (20) is balanced due to the position of the center of mass (MP) in the area of ​​the swivel axis (A). [6] Grinding machine (100) according to one of claims 1 to 5, characterized by that it has three additional axes (X, Y, Z) which are designed as linear axes, whereby - a first of these additional axes (Y) extends parallel to the workpiece spindle axis (C), - a second of these additional axes (Z) extends parallel to the pivot axis (A), and - where the three additional axes (X, Y, Z) form a Cartesian coordinate system. [7] Grinding machine (100) according to one of claims 1 to 6, characterized by that the grinding tool (20) is a grinding worm. [8] Grinding machine (100) according to one of claims 1 to 6, characterized by that it is a gear grinding machine which is designed for grinding straight and helical gears on the gear workpiece (10). [9] Grinding machine (100) according to one of claims 1 to 6, characterized by that it is a gear grinding machine which is designed for grinding the gear workpiece (10) which is arranged in the gear grinding machine on the workpiece spindle (110) with a vertical workpiece spindle axis (C), wherein the pivot axis (A) is perpendicular to the workpiece spindle axis (C).

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