Tool heads and gear cutting machines for hard peeling or hob peeling.

Abstract

A tool head for manufacturing or machining teeth, particularly internal teeth, of a workpiece in the kinematics of hob peeling, wherein the teeth rotate about a tooth rotation axis of the teeth, the peeling tool is held in the tool head and rotates about the tool rotation axis of the peeling tool at an axial intersection angle between the tooth rotation axis and the tool rotation axis, the axial intersection angle is not zero, and defines the orientation of the tool rotation axis relative to the tool head; and a shaft attached to the tool head and rotating about a drive shaft rotation axis of the shaft, which is rotationally driven to machine teeth, wherein there is an orientation of the tool rotation axis of at least 15° and not more than 85°, used for the deviation of the orientation of the drive shaft rotation axis from an axial position oriented at an axial intersection angle with respect to the tooth rotation axis, and is angled with respect to a plane perpendicular to the drive shaft rotation axis.

Description

Technical Field

[0001] The present invention relates to a tool head for manufacturing or machining teeth of a workpiece, particularly internal teeth, by means of a peeling tool in the kinematics of hobbing peeling, wherein the teeth rotate about a tooth rotation axis of the teeth, the peeling tool is held on the tool head and rotates about a tool rotation axis of the peeling tool at an axis crossing angle Σ between the tooth rotation axis and the tool rotation axis, and the axis crossing angle Σ is not zero, and also to a gear cutting machine for hobbing peeling or hard peeling of teeth. Background Art

[0002] Such tool heads for hobbing peeling are well known in the prior art and are described, for example, in Patent Document 1. They are generally rotatable or pivotable on the carriage arrangement of a hobbing peeling machine, so that the adjustment of the axis crossing angle can be performed by adjusting the rotation angle of this rotatable holder on the axis crossing angle Σ between the tooth rotation axis and the tool rotation axis. A typical axis crossing angle adjustment for hobbing peeling is 20°, for example. Prior Art Literature Patent Literature

[0003] Patent Document 1 German Published Patent Application No. 102017011978(A1) Summary of the Invention Problem to be Solved by the Invention

[0004] The present invention is based on the object of advantageously further developing a tool head of the type described above, in particular to obtain greater machining flexibility. Means for Solving the Problem

[0005] This objective is achieved by the present invention through a further development of the type of tool head mentioned at the beginning, which is substantially characterized by an orientation of the tool rotation axis of at least 15° and no more than 85°, the orientation being used for the deviation of the orientation of the drive shaft rotation axis from an axial position oriented with respect to the tooth rotation axis at an axial intersection angle Σ, and angled with respect to a plane perpendicular to the drive shaft rotation axis.

[0006] The tool head configuration according to the present invention reduces the risk of collision when machining at a desired axial crossing angle, particularly when machining internal teeth. This is because the angled orientation allows the swivel angle of the rotating drive shaft to be set smaller than the axial crossing angle, and in particular, it can be set to zero, i.e., parallel to the axis of rotation of the workpiece. This results in a lower overhang width for the overhang still required for axial crossing, and makes it possible to machine workpieces with larger tooth widths than standard hob peeling configurations, or to machine workpieces at a desired axial crossing angle without having to machine at an undesirably small axial crossing angle due to the risk of collision.

[0007] Preferably, this angled orientation with respect to the plane is 82° or less, more preferably 79° or less, and particularly 76° or less. It is also preferable that the angled orientation with respect to the plane is at least 30°, more preferably at least 40°, particularly at least 50°, or even more preferably at least 56°. The angled orientation may also be 60° or more, 63° or more, or even 66° or more, and in one embodiment may be 70°.

[0008] In a particularly preferred embodiment, the tool holder is provided to have a tool bearing for the axial portion of the tool shaft, which is rotatable about the tool rotation axis and non-rotatably connected to the peeling tool. This ensures that the peeling tool continues to rotate reliably.

[0009] Therefore, the tool shaft is a shaft whose orientation coincides with the tool rotation axis. The driven shaft may be the motor spindle shaft, or a shaft coupled to the motor spindle shaft, preferably a shaft extending parallel to the drive unit, and especially coaxially with it. Needless to say, the tool shaft itself should be made as short as possible to minimize the radial offset (radial overhang) from the driven shaft.

[0010] In a more preferred embodiment, a transmission device is provided that transmits the rotation of a driven shaft to a tool shaft and transmits torque, thereby enabling a change in the orientation of the rotating shaft. For example, this can be formed by a constant velocity joint, as will be described in detail below.

[0011] As described below with reference to the drawings, the rotating drive shaft and the tool shaft, which has the orientation of the tool rotation axis, are directly continuous shafts. Therefore, there is only one orientational twist between the rotating drive shaft and the tool shaft. Due to this orientational twist, or angled orientation, the axial intersection angle between the tool spindle axis and the workpiece axis corresponds to the axial intersection angle between the driven shaft and the workpiece rotation axis (the axial intersection angle in conventional hob peeling, where the orientation of the tool axis coincides with the orientation of the rotating drive shaft supporting the peeling wheel), which is altered by this twist.

[0012] Similarly, as described below with reference to the drawings, the rotating drive shaft extends into the tool head and is moved or pivoted in the movement of the tool head along its axis of movement, e.g., X1, Y1, Z1, and A1.

[0013] For high synchronization accuracy between the tool and the workpiece, the transmission should preferably be designed to have low excitation behavior. In this case, it is conceivable to keep the transmission under preload, for example, by applying a preload to the intermediate gearbox.

[0014] In a more preferred embodiment, a tool clamping device is provided for clamping a peeling tool to a tool shaft so that it cannot rotate relative to it. Thus, clamping the peeling tool can be performed in substantially the same manner as is well known to those skilled in the art when clamping a conventional tool head, i.e., a clamping system provided for this purpose and known in numerous versions.

[0015] The peeling tool can also be attached to the tool shaft in a simpler way, for example, via a screw connection, preferably via a wrench surface, while centering the tool.

[0016] Furthermore, in a preferred modification, the tool holder is firmly connected to a bearing for the rotating drive shaft in the machining state, and in particular, is detachably connected to this bearing. This firm connection improves the overall rigidity, smooth operation, and consequently, machining accuracy of the system. The optionally provided detachability ensures that, in addition to or as an alternative to the tool replacement described above, the peeling tool can also be replaced along with its bearing.

[0017] Preferably, for connection, the end flange of the bearing for the rotating drive shaft has a contact surface perpendicular to the axis of rotation of the rotating drive shaft, and the contact surface of the tool holder extends at an angle with respect to the axis of rotation of the tool; however, in principle, such inclination may be reversed, or partial inclination of the contact surface may be provided on both sides.

[0018] The connection between the rotating drive shaft and the drive mechanism can be achieved by an existing system known for clamping the tool shaft, such as an HSK holder. On the housing side, a bearing for the rotating drive shaft can be mounted toward the drive side via an interface in the tool head.

[0019] In this regard, a more preferred embodiment provides a centering mechanism for connecting a bearing for the rotating drive shaft to the drive side of the tool head. This simplifies assembly and ensures an automatic and precise mating connection.

[0020] In another possible embodiment, the rotating drive shaft is driven directly by a drive device provided on the tool head. Thus, the rotating drive shaft may be a restarted tool spindle of the direct drive device, or an indirect drive device for the rotating drive shaft may be used. However, the aforementioned parallel, and especially coaxial, position of the rotating drive shaft relative to the drive shaft is preferred, including its direct rigid coaxial coupling.

[0021] In a preferred design, the tool head is designed to be rotatably mounted to the support of the gear cutting machine about a pivot axis. This further increases flexibility, as the axial intersection angle between the tool rotation axis and the workpiece axis remains adjustable despite the angled orientation value given by the design being a fixed value. However, in different embodiments, simpler machine designs are conceivable in which the axial intersection angle of the machining is determined by defining the angled orientation, but may also be achievable by changing the bearings.

[0022] In this case, preferably, the principal directional component of the drive shaft rotation axis extends perpendicular to the swivel axis (A). In particular, the drive shaft rotation axis can extend perpendicular to the swivel axis. In the latter case, a tool spindle and swivel axis of a normal configuration (apart from the angled orientation according to the present invention) result. The structural relief angle for machining can already be achieved using the portion of the directional component that does not extend perpendicular to the swivel axis.

[0023] When the axis of rotation of the drive shaft and the axis of rotation of the workpiece are oriented parallel to each other, it is assumed that the axis of rotation of the driven shaft is spaced (tangentially) away from the plane stretched between the axis of rotation of the workpiece and the radial feed axis.

[0024] In a further preferred embodiment, the drive shaft rotation axis and the tool rotation axis extend in planes parallel to each other, particularly in the same plane. This simplifies the coupling of the transmission device and can simplify calculation of the mechanical axis setting controlled by the control device of the gear hobbing machine for machining.

[0025] As already mentioned above, there are several available possibilities for transmitting torque across an angle. Constant velocity joints or gears are particularly preferably used. In a preferred embodiment, the ratio of the length of the tool shaft to the diameter of the tool shaft extending in the direction of the tool rotation axis is 0.4 or more, preferably 0.6 or more, particularly 0.8 or more. This ratio should preferably be 5 or less, particularly 4 or less. This stabilizes the bearing and improves the smoothness of operation.

[0026] The bearing of the tool shaft and the bearing of the rotationally driven shaft in the tool head should be designed to be as rigid as possible in order to reduce dynamic excitation behavior. The diameter of the corresponding shaft is ideally selected to be as large as possible, so as to obtain a shaft with torsional rigidity as high as possible. In this case, materials with a high elastic modulus are also considered. The overall design consisting of the rotationally driven shaft, the transmission device and the tool shaft is preferably designed to have a compact structure, particularly when machining internal teeth with a small pitch circle diameter.

[0027] In a further preferred embodiment, the ratio of the diameter of the tool shaft to the diameter of the (peeling) tool is 0.17 or more, preferably 0.24 or more, particularly 0.3 or more, and / or 0.75 or less, preferably 0.67 or less, particularly 0.6 or less. Also preferably, the length of the tool shaft is less than the length of the rotationally driven shaft, preferably at least less than 0.8 times, more preferably less than 0.6 times, particularly less than 0.4 times.

[0028] This provides a favorable combination of the desired structural stability and low overhang according to the present invention.

[0029] Furthermore, the present invention protects gear cutting machines having tool heads designed in this manner, as well as, from a process engineering standpoint, hard peeling or hob peeling methods using such tool heads.

[0030] Preferably, in the tooth height region of the machined workpiece, the radial width of the tool head (including the tool) with respect to the workpiece rotation axis is smaller than the tip circle of the machined internal teeth. In this case, the tool head is smaller with respect to the radial width at an angle inclined by the axis intersection angle, particularly at the height of the transmission device, and in any case is no more than 1.2 times, and especially no more than 1.1 times, the radial width of the tool at an angle inclined by the axis intersection angle.

[0031] Preferably, the product of the length of the tool shaft, including the axial width of the peeling wheel, and the sine of the axial intersection angle is less than a predetermined maximum value.

[0032] This maximum value is preferably given by the difference between the root of the outer diameter of the workpiece teeth (scaled by the geometric factors of the tool) and half the lateral dimension of the tool head in the region of the rotating drive shaft at the height of the transmission device.

[0033] The geometrical factor of the tool is preferably the square root of the difference between the outer diameter of the peeling wheel and half the lateral dimension of the tool head in the area of ​​the tool shaft at the height of the transmission device. In this way, even relatively wide internal teeth can be machined economically.

[0034] It is understood that the control of such gear cutting machines is adapted in accordance with the change of the tool head, and therefore the position and movement of the machine axis are set according to the angled orientation and axial distance of the peeling tool relative to the transmission device, or the transmission device and axial reference (approximately the height of the swivel axis on the machine side) of the rotating drive shaft. [Brief explanation of the drawing]

[0035] Further features, details, and advantages of the present invention can be found in the following description with reference to the accompanying drawings. [Figure 1] A gear cutting machine is schematically shown along with its machine axis. [Figure 2] Figure 1 shows the area of ​​the tool head compared to a conventional tool head, along with its relative position to the internal teeth. [Figure 3] This shows a comparison with conventional hob peeling. [Figure 4] This shows a comparison with conventional hob peeling. [Figure 5] This shows machining using a different axis intersection angle than Figure 2. [Modes for carrying out the invention]

[0036] The machine tool shown in Figure 1 is a machine 100 designed for hob peeling using a peeling wheel S. On the workpiece side, the machine 100 has a tool table 80, which is mounted to the machine bed 90 in a rotary drive manner and can clamp a workpiece to be machined (not shown in Figure 1), which has, for example, internal teeth to be machined, so that it can rotate around the machine rotation axis C1 on the workpiece side.

[0037] On the tool side, the machine 100 has a linear machine axis X1 for radial positioning movement of the tool relative to the workpiece, an axis Z1 for movement of the tool along the axial direction of the table axis C1, and an axis Y1 for tangential relative movement between the tool and the workpiece. These linear axes X1 and Z1 are perpendicular to each other and are implemented via a carriage configuration 70 in which a linear carriage 72 for movement of X1 carries a vertical carriage 74 for movement of Z1. In this embodiment, the tool head 78 carrying the tool S, which also carries a CNC drive as a direct drive for tool rotation having a rotation axis B1, can move together with the linear carriage 76 for tangential movement Y1. However, the tangential carriage 76 is rotatably positioned on the vertical carriage 74 with a pivot axis A1, and therefore the movement of its carriage is only horizontal in the position shown in Figure 1, otherwise it is tilted with respect to the Z1 axis by a set pivot angle A1.

[0038] As described above, the gear cutting machine in Figure 1 is a conventional vertical machining center (vertical workpiece rotation axis). The present invention relates to a modified tool head 78, and the basic structure and machine axes C1, X1, Y1, Z1, A1 can be easily used in embodiments for design according to the present invention. The present invention is not limited to a vertical machining center or a specific machine axis arrangement in terms of basic design, and can be designed, for example, as a horizontal machining center or to have fewer machine axes. The tool head 78' according to the present invention will be described below, newly denoted by reference numeral 7.

[0039] The tool head 7 is shown in Figure 2 together with the internally toothed workpiece W. It is clear that the tool head 7 comprises a second portion 7b close to the peeling wheel S, which is designed at a certain angle and forms a tool holder that defines the orientation of the tool rotation axis S1 relative to the tool head 7, and an adjacent first portion 7a which forms bearings for the motor and the rotating drive shaft 6. As is common in hob peeling machines, this can be formed by a tool spindle drive (direct drive).

[0040] The second part 7b is flanged to the first part 7a and can be replaced with another, particularly different, second part (not shown).

[0041] Figure 2 shows that an angle of 70° φ is set between the tool rotation axis S1 (corresponding to the orientation of the tool shaft 4) and a plane perpendicular to the drive shaft rotation axis B1 (oriented according to the rotated drive shaft 6). The orientation of the rotated drive shaft 6 relative to the workpiece rotation axis C1 is the same as in Figure 1, and as a result, tooth machining can be performed under an axis crossing angle Σ of 20°.

[0042] The risk of collision is significantly lower than with conventional hob peeling because the overhang that is misaligned with the orientation of the workpiece rotation axis is only in the second portion 7b, and the entire tool head 7 does not need to overhang by pivoting (for example, around the conventional rotation axis A1) in order to machine teeth under an axis crossing angle of Σ=20°, for example. Figures 3 and 4 show that collisions have already occurred during conventional hob peeling when machining equivalent workpieces (Figure 3), or that a significantly smaller axis crossing angle Σ is used to avoid collisions. c It is clearly shown that the following must be used (Figure 4). In this regard, the present invention increases the flexibility of the hob peeling method with respect to potentially machinable workpieces and with respect to the greatest possible selection of axis intersection angles for machining.

[0043] Figure 2 shows that the rotation axis B1 of the driven shaft 6 is offset tangentially by ΔY with respect to the workpiece rotation axis C1, and as a result, machining can be performed at the intersection of axis S1 and axis C1 (central machining). However, it is understood that eccentric machining can also be performed, for example, by a tangential shift, or by an angular plane component of angle φ perpendicular to the plane of Figure 2 (the plane perpendicular to the radial axis X1).

[0044] As can be seen from Figures 1 and 2, the rotating drive shaft 6 extends into the tool head 78 (Figure 1) and is moved or rotated when the moving axes X1, Y1, Z1 and A1 move. It is also clear that the rotating drive shaft 6 and the tool shaft 4, which has the orientation of the tool rotation axis S1, are directly continuous shafts. Therefore, there is only one directional twist between the rotating drive shaft 6 and the tool shaft 4.

[0045] From the display in Figure 5, it is clear that with the tool head 7 in Figure 2, machining is possible under an axis crossing angle Σ of 30° when the part 7a is rotated again by A = 10° around the pivot axis A1. Here, the axis crossing angle Σ is given by A + (90° - φ).

[0046] In another example (not shown), the tool head 7 can be rotated in the opposite direction compared to Figure 5, and as a result, for example, when A is -10°, an axis crossing angle Σ of 20° can be achieved even with a bending angle φ of 60°.

[0047] The present invention is not limited to the features specifically shown in the exemplary embodiments. Rather, the individual features of the following claims, as well as the above description and the following claims, may be essential, individually and in combination, for carrying out the present invention in its different embodiments.

Claims

1. A tool head (7) for manufacturing or machining teeth, particularly internal teeth, of a workpiece (W) in the kinematics of hob peeling, wherein the teeth rotate about a tooth rotation axis (C1), the peeling tool (S) is held in the tool head (7) and rotates about a tool rotation axis of the peeling tool (S) at an axial intersection angle (Σ) between the tooth rotation axis (C2) and the tool rotation axis (S1), the axial intersection angle (Σ) is not zero, A tool head comprising: a tool holder (7b) that defines the orientation of the tool rotation axis (S1) relative to the tool head (7); and a shaft (6) that is attached to the tool head (7) and rotates about the drive shaft rotation axis (B1) of the shaft (6), and is rotationally driven to machine the teeth, A tool head characterized by an orientation (φ) of the tool rotation axis (S1) of at least 15° and 85° or less, which is used to deviate the orientation of the drive shaft rotation axis (B1) from an axis position oriented with respect to the tooth rotation axis (C1) at the axis intersection angle (Σ), and which is angled with respect to a plane perpendicular to the drive shaft rotation axis (B1).

2. The tool head according to claim 1, wherein the tool holder has a tool bearing for the axial portion of a tool shaft (4) that is rotatable about the tool rotation axis and non-rotatably connected to the peeling tool.

3. The tool head according to claim 2, further comprising a transmission device (5) for transmitting the rotation of the rotating drive shaft to the tool shaft (4).

4. The tool head according to claim 2 or 3, further comprising a tool clamping device for clamping the peeling tool to the tool shaft (4) in a manner that prevents relative rotation.

5. The tool head according to any one of claims 1 to 4, wherein the tool holder (7b) is firmly connected to the bearing (7a) for the rotating drive shaft (6) in a machined state, and in particular is detachably connected to the bearing (7a).

6. The tool head according to claim 5, further comprising a centering mechanism for connecting the bearing (7a) for the rotating drive shaft to the drive side of the tool head.

7. The tool head according to any one of claims 1 to 6, wherein the rotating drive shaft (6) is directly driven by a drive device provided on the tool head.

8. A tool head according to any one of claims 1 to 7, which is mounted on the carrier of a gear cutting machine so as to be rotatable about a pivot axis (A1).

9. The tool head according to claim 8, wherein the main directional component of the drive shaft rotation axis extends perpendicular to the pivot axis (A1).

10. The tool head according to claim 8 or 9, wherein the main directional component of the tool rotation axis is perpendicular to the pivot axis (A1).

11. The tool head according to any one of claims 1 to 10, wherein the drive shaft rotation axis and the tool rotation axis extend in planes parallel to each other, particularly in the same plane.

12. The tool head according to any one of claims 3 to 11, wherein the transmission device (5) has a constant velocity joint or a gear.

13. The tool head according to any one of claims 1 to 12, wherein the ratio of the length of the tool shaft (4) to the diameter of the tool shaft (4) extending in the direction of the tool rotation axis is 0.4 or more, preferably 0.6 or more, and particularly 0.8 or more. This ratio should preferably be 5 or less, and more particularly 4 or less.

14. The tool head according to any one of claims 1 to 13, wherein the ratio of the diameter of the tool shaft to the diameter of the (peeling) tool is 0.17 or more, preferably 0.24 or more, particularly 0.3 or more, and / or 0.75 or less, preferably 0.67 or less, particularly 0.6 or less.

15. A gear cutting machine (100) for hob peeling or hard peeling of teeth, comprising a workpiece spindle drive device for driving a workpiece, in particular an internally toothed workpiece (W), and a tool head (7) according to any one of claims 1 to 14.

16. A method for hard peeling or hob peeling a workpiece (W), particularly an internally toothed workpiece, using a tool head (7) according to any one of claims 1 to 15, wherein the product of the length of the tool shaft, including the axial width of the peeling wheel, and the sine of the axial intersection angle is less than a predetermined maximum value.

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