METHOD FOR GEAR CUTTING OF BEVEL GEAR WORKPIECES

Abstract

Method for gear cutting a bevel gear workpiece, wherein a preliminary machining phase includes a first machining procedure, wherein a first relative infeed movement moves the gear cutting tool into a first starting position relative to the bevel gear workpiece, the gear cutting tool penetrates the material of the bevel gear workpiece relative to the bevel gear workpiece, proceeding from the first starting position up to a first end position, and the gear cutting tool and bevel gear workpiece carry out a first rolling procedure in a first rolling range, carrying out a further rolling procedure, in order to post-machine at least one of the tooth gaps on the bevel gear workpiece using the rotationally-driven gear cutting tool or another rotationally-driven gear cutting tool, wherein in the scope of this further rolling, a rolling rotation is carried out in a further rolling range, which differs from the first rolling range.

Claims

1. A method comprising: cutting a bevel gear workpiece in a gear cutting machine, including: (a) executing a preliminary machining phase comprising performing a rolling procedure and machining therewith at least one tooth gap on the bevel gear workpiece using a rotationally-driven gear cutting tool, including performing at least one first machining procedure comprising performing a first relative infeed movement moving the gear cutting tool into a first starting position relative to the bevel gear workpiece, penetrating the gear cutting tool into material of the bevel gear workpiece relative to the bevel gear workpiece from the first starting position to a first ending position, and performing a first rolling procedure in a first rolling range with the gear cutting tool and the bevel gear workpiece, wherein a material allowance remains on the bevel gear workpiece after the preliminary machining phase; and (b) executing a post-machining phase comprising performing a further rolling procedure proceeding from a further starting position and post-machining therewith at least one of the at least one tooth gap on the bevel gear workpiece using the rotationally-driven gear cutting tool or using another rotationally-driven gear cutting tool, including performing a rolling rotation in a further rolling range, wherein the first starting position defines a cradle angle and the further starting position defines a different cradle angle, and further including removing the material allowance and generating a final flank geometry.

2. A method according to claim 1, wherein executing the preliminary machining phase includes performing a second machining procedure comprising penetrating the gear cutting tool into the material of the bevel gear workpiece relative to the bevel gear workpiece from a second starting position to a second ending position, and performing, with the gear cutting tool and the bevel gear workpiece, a second rolling procedure in a second rolling range that differs from the first rolling procedure.

3. A method according to claim 2, wherein the first rolling procedure and the second rolling procedure each including performing partial through rolling and the further rolling procedure includes performing complete through rolling.

4. A method according to claim 2, wherein performing the second machining procedure includes performing a second relative infeed movement moving the gear cutting tool into the second starting position relative to the bevel gear workpiece.

5. A method according to claim 2, wherein performing the rolling procedure includes performing a multistage plunging-rolling method, wherein performing the at least one first machining procedure includes performing a first productive plunging movement from the first starting position to the first ending position, and performing the second machining procedure includes performing a second productive plunging movement from the second starting position up to the second end position.

6. A method according to claim 1, including performing the first rolling procedure in a first cradle angle range and performing the further rolling procedure in a second cradle angle range that is different from the first cradle angle range.

7. A method according to claim 1, including beginning the first rolling procedure at a first initial cradle angle and beginning the further rolling procedure at a second initial cradle angle that is different from the first initial cradle angle.

8. A method according to claim 1, wherein the material allowance remains on the at least one tooth gap of the bevel gear workpiece after the first rolling procedure, and the step of removing said material allowance is performed during the step of performing the further rolling procedure.

9. A method according to claim 1, including (i) performing the at least one first machining procedure with respect to every of the at least one tooth gap on the bevel gear workpiece in a gap-by-gap manner; and (ii) at a time after completing step (i), performing the further rolling procedure in a gap-by-gap manner.

10. A method according to claim 1 comprising performing the method in a gap-spanning manner.

11. A method according to claim 1, wherein the machining step includes generating the at least one tooth gap from solid material of the bevel gear workpiece during the step of performing that at least one first machining procedure.

12. A method according to claim 11, wherein the solid material of the bevel gear workpiece is not hardened prior to the step of performing the at least one first machining procedure.

13. A method according claim 1, wherein the machining step includes grinding or milling of the at least one tooth gap.

14. A method according to claim 1, wherein the further rolling range is greater than the first rolling range.

15. A method according to claim 2, including performing the first rolling procedure in a first cradle angle range and performing the further rolling procedure in a second cradle angle range that is different from the first cradle angle range.

16. A method according to claim 2, including beginning the first rolling procedure at a first initial cradle angle and beginning the further rolling procedure at a second initial cradle angle that is different from the first initial cradle angle.

17. A method according to claim 2, wherein the material allowance remains on the at least one tooth gap of the bevel gear workpiece after the first rolling procedure, and the step of removing said material allowance is performed during the step of performing the further rolling procedure.

18. A method according claim 2, wherein the machining step includes grinding or milling of the at least one tooth gap.

19. A method according to claim 3, including performing the first rolling procedure in a first cradle angle range and performing the further rolling procedure in a second cradle angle range that is different from the first cradle angle range.

20. A method according to claim 3, wherein the material allowance remains on the at least one tooth gap of the bevel gear workpiece after the first rolling procedure, and the step of removing said material allowance is performed during the step of performing the further rolling procedure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Other advantages and features will become apparent from the following detailed description, which are understood not to be limiting, and are described in greater detail hereafter with reference to the drawings.

[0082] FIG. 1A schematically shows a known method for the preliminary machining of rolled tooth gaps;

[0083] FIG. 1B schematically shows the method of FIG. 1A, which is used for the post-machining of the rolled tooth gaps;

[0084] FIG. 2 schematically shows a virtual crown gear of a bevel gear gear cutting machine together with a bevel gear workpiece and a gear cutting tool, as is known;

[0085] FIG. 3 schematically shows a perspective view of a known depth grinding method of a bevel gear pinion;

[0086] FIG. 4 schematically shows a perspective view of a known bevel gear pinion and a tooth gap which was generated on this bevel gear pinion;

[0087] FIG. 5A schematically shows substeps of a first machining procedure;

[0088] FIG. 5B schematically shows substeps of a second machining procedure;

[0089] FIG. 5C schematically shows substeps of a post-machining phase; and

[0090] FIG. 6 shows a perspective view of a grinding machine in which methods disclosed herein can be used.

DETAILED DESCRIPTION

[0091] This relates to a method which was specially developed for milling or grinding gear teeth on a bevel gear workpiece 11 in a gear cutting machine 100.

[0092] Exemplary substeps of one embodiment of the method are shown in FIGS. 5A to 5C. These are methods here in which two machining procedures are carried out in the scope of the preliminary machining phase. The second machining procedure, which is shown in FIG. 5B, is optional.

[0093] FIG. 6 shows a perspective view of a grinding machine 100, in which methods disclosed can be used. However, such methods can also be used in other gear cutting machines.

[0094] One embodiment of a method comprises the following steps, which are described with reference to FIGS. 5A to 5C. The illustration style of FIGS. 5A to 5C is similar to illustration styles used in the book mentioned above: Kegelrder; Grundlagen, Anwendungen.

[0095] The method can begin with carrying out a relative infeed movement PA, to move a cup grinding wheel 10 (or another gear cutting tool 10) into a starting position AP1 in relation to the bevel gear workpiece 11. This starting position AP1 is defined, inter alia, by a first cradle angle. Reference is generally made hereafter to gear cutting tools 10, even if a cup grinding wheel 10 is shown by way of example in the figures. Simultaneously or after reaching the starting position AP1, the gear cutting tool 10 is rotationally driven around a tool spindle axis A1 of the gear cutting machine 100. The relative infeed movement PA can take place using one or more axes of the gear cutting machine 100. The infeed movement PA can be a linear movement or it can follow a curved path. The infeed movement PA can also comprise multiple linear and/or curved movements.

[0096] The infeed movement PA is a nonproductive movement in at least some embodiments. The block arrow PA is therefore shown in white.

[0097] From the starting position AP1 in FIG. 5A, a plunging-rolling method of a first machining procedure 110 can begin in all embodiments, in order to generate at least one tooth gap 13 in the material of the bevel gear workpiece 11 by grinding or milling. This plunging-rolling method comprises at least the following partial processes. The use of the numerals first, second, etc. is not to define a chronological sequence. These numerals are rather used for simpler naming of the individual procedures.

[0098] In the scope of a first plunging procedure PB, the penetration of the gear cutting tool 10 into the material of the bevel gear workpiece 11 takes place. This is a productive first plunging procedure PB. The penetration begins at the starting position AP1 and occurs up to a first plunging end position 1.TEP. During the productive first plunging procedure PB, material is removed by grinding or milling, as shown in FIG. 5A by the black arrow PB. The first plunging procedure PB results from one or more relative movements of one or more axes of the gear cutting machine 100. The first plunging procedure PB can be a linear movement or it can follow a curved path. The first plunging procedure PB can also comprise multiple linear and/or curved movements.

[0099] Now, for example, as shown in FIG. 5A, a first rolling procedure WA can follow, in which the gear cutting tool 10 and the bevel gear workpiece 11 execute relative movements having superimposed rolling rotation 2. A corresponding rolling rotation 2 is shown in FIG. 3 by way of example. The rolling rotation 2, as is used here relates to a rotational movement of the bevel gear workpiece 11 around the workpiece spindle axis B. The relative movements of the rolling procedure WA having superimposed rolling rotation 2 result in a complex three-dimensional movement of the gear cutting tool 10 in relation to the bevel gear workpiece 11. In FIG. 5A, this complex movement sequence is symbolized by the black arrow WA. At the end of the rolling procedure WA, a first rolling end position 1. WEP is reached.

[0100] For example, in FIG. 5A, a relative withdrawal movement PC can take place up to a first end position EP1. This withdrawal movement PC can be a linear movement or it can follow a curved path. The withdrawal movement PC can also comprise multiple linear and/or curved movements. The withdrawal movement PC can also result from one or more relative movements of one or more axes of the gear cutting machine 100.

[0101] The withdrawal movement PC can be a productive or nonproductive movement.

[0102] The further steps, which can be carried out in the scope of the preliminary machining phase on the same tooth gap 13 as the steps of FIG. 5A, are shown in FIG. 5B. This procedure is referred to here as gap-by-gap machining, since every gear 13 of the bevel gear workpiece 11 is subjected to all substeps of FIGS. 5A and 5B, before a next tooth gap is pre-machined accordingly. The substeps of FIG. 5B are optional. The method can therefore also pass directly to the steps of FIG. 5C after the execution of the steps of FIG. 5A.

[0103] However, it is also possible to perform an indexing rotation of the bevel gear workpiece 11 around the workpiece spindle axis B after the steps of FIG. 5A, in order to preliminarily machine a next tooth gap 13 of the bevel gear workpiece 11 according to FIG. 5A. This procedure can be repeated until all tooth gaps 13 have been preliminarily machined according to FIG. 5A. The steps of FIG. 5B or also the steps of FIG. 5C directly can then follow tooth gap 13 by tooth gap 13. This procedure is referred to here as gap-spanning.

[0104] However, it is also possible to carry out the steps of FIG. 5B after the steps of FIG. 5A on the tooth gap 13 which was previously subjected to the steps of FIG. 5A. In this case, an indexing rotation of the bevel gear workpiece 11 around the axis B first takes place after the steps of FIG. 5B.

[0105] However, it is also possible to carry out the steps of FIG. 5C after the steps of FIG. 5A and the steps of FIG. 5B, before an indexing rotation of the bevel gear workpiece 11 take place around the axis B, in order to carry out the steps of FIGS. 5A to 5C on a next tooth gap 13.

[0106] As shown in FIG. 5B, a relative plunging or piercing movement PF can be carried out in the scope of an optional second machining procedure 111, in order to cause the gear cutting tool 10 to penetrate into the material in relation to the bevel gear workpiece 11 from a second starting position AP2 up to a further plunging end position 2.TEP. This plunging or piercing movement PF can be a linear movement or a can follow a curved path. It can also comprise multiple linear and/or curved movements. The movement PF can also result from one or more relative movements of one or more axes of the gear cutting machine 100.

[0107] Now, for example, as shown in FIG. 5B, a second rolling procedure WB can follow, in which the gear cutting tool 10 and the bevel gear workpiece 11 execute the relative movements of a rolling procedure with overlaid rolling rotation w3. The second rolling procedure WB is longer in the exemplary embodiment shown than the first rolling procedure WA, as indicated by the block arrows WA and WB of different lengths. The first rolling procedure WA can also be longer than the second rolling procedure WB, however.

[0108] The corresponding relative movements with overlaid rolling rotation w3 result in a complex three-dimensional movement of the gear cutting tool 10 in relation to the bevel gear workpiece 11. This complex movement sequence is symbolized by the black arrow WB in FIG. 5B. At the end of the rolling procedure WB, a second rolling end position 2.WEP is reached.

[0109] At least some embodiments comprise at least two different rolling procedures WA and WB. Rolling procedures are referred to as different rolling procedures WA and WB in the present context,

[0110] which differ due to their starting positions (1.TEP, 2.TEP) and/or end positions (1.WEP, 2.WEP), and/or

[0111] in which the rolling procedures WA, WB are of different lengths (for example, measured in degrees of the cradle angle), and/or

[0112] which are carried out with different depth infeeds PB, PF of the gear cutting tool 10 (for example, the cup grinder wheel) in relation to the bevel gear workpiece 11 (i.e., the arrow PF is longer, for example, than the arrow PB), and/or

[0113] which differ due to their starting positions (1.TEP, 2.TEP) and their rolling speeds or due to their end positions (1.WEP, 2.WEP) and their rolling speeds, and/or

[0114] which do not roll through completely from a rolling start AP4 up to the rolling end 3.WEP, as is typical in the prior art, as takes place in the post-machining phase 112 (see FIG. 5C).

[0115] Now, for example, as shown in FIG. 5B, a relative withdrawal movement PG can take place up to a second end position EP2.

[0116] In at least some embodiments, the withdrawal movement PG can be a linear movement or it can follow a curved path. The withdrawal movement PG can also comprise multiple linear and/or curved movements. The movement PG can also result from one or more relative movements of one or more axes of the gear cutting machine 100.

[0117] The withdrawal movement PG can be a productive or nonproductive movement in all embodiments.

[0118] In the case of a gap-by-gap machining, the post-machining 112 of FIG. 5C now takes place.

[0119] As shown in FIG. 5C, the post-machining phase 112 comprises a movement PH in at least some embodiments, to infeed the gear cutting tool 10 in relation to the bevel gear workpiece 11, for example, from a third starting position AP3 up to a fourth starting position AP4 outside the material. This third starting position AP3 differs from the first starting position AP1 due to the cradle angle. I.e., the rolling procedure WC of the post-machining phase 112 proceeds from a different cradle angle than the rolling procedure WA.

[0120] This movement PH can be a linear movement or it can follow a curved path. It can also comprise multiple linear and/or curved movements. The movement PH can also result from one or more relative movements of one or more axes of the gear cutting machine 100.

[0121] In at least some embodiments, for example, as shown in FIG. 5C, a third rolling procedure WC can follow, in which the gear cutting tool 10 and the bevel gear workpiece 11 execute relative movements having overlaid rolling rotation w4. The third rolling procedure WC is longer in the example shown in the first rolling procedure WA (and than the second optional rolling procedure WB) as indicated by the block arrows WA, WB, and WC of different lengths. Complete rolling through of the corresponding tooth gap 13 takes place in the scope of the third rolling procedure WC.

[0122] The third rolling range can comprise an incoming range and/or an outgoing range. To be able to show this in FIG. 5C, the black block arrow WC at the rolling start (on top in FIG. 5C) and at the rolling end (at the bottom in FIG. 5C) has a white region in each case. It is thus to be shown that the entire rolling procedure WC does not have to be productive.

[0123] In comparison to FIGS. 5A, 5B, and 5C, it can also be seen that the gear cutting tool 10 can be located in different starting positions in each case in relation to the bevel gear workpiece 11. The gear cutting tool is provided with the reference sign 10* in the position of FIG. 5A in FIG. 5B and FIG. 5C. The gear cutting tool is provided with the reference sign 10** in the position of FIG. 5B in FIG. 5C. This type of illustration is solely schematic in nature and is to serve for better comprehension.

[0124] In addition, a portion of the material of the bevel gear workpiece 11 is schematically indicated in FIGS. 5A, 5B, and 5C. This illustration of the bevel gear workpiece 11 is also solely schematic in nature and is to serve for better comprehension.

[0125] In the case of gap-by-gap machining, after the steps of FIG. 5C, an indexing rotation of the bevel gear workpiece 11 takes place and the method of FIGS. 5A and 5C or FIGS. 5A, 5B, and 5C is repeated after reaching the next starting position AP1 with the step PB.

[0126] In the examples which are shown and described here, it is to be noted that at least a part of the mentioned movements can run in overlaid form.

[0127] The first rolling procedure WA can begin, for example, even before reaching the first plunging end position 1.TEP, to mention only one example.

[0128] The first rolling procedure WA can be stopped, for example, even before reaching the position 1.WEP, to mention a further example.

[0129] The second rolling procedure WB, if provided, can begin, for example, even before reaching the second plunging end position 2.TEP, to mention only one example.

[0130] The second rolling procedure WB, if provided, can be stopped, for example, even before reaching the position 2.WEP, to mention a further example.

[0131] The grinding or cutting conditions on the gear cutting tool 10 can be optimized on the basis of an allocation of the steps into multiple substeps or rolling procedures. In the method of FIGS. 5A and 5B, a part of the removal ability is transferred from the profile head 12 of the cup grinding wheel 10 to the side flanks 14 (see FIG. 5A) of the cup grinding wheel 10.

[0132] At least some embodiments comprise at least one relative infeed movement (for example, PA in FIG. 5A) to move the gear cutting tool 10 into a starting position (for example, AP1 in FIG. 5A) in relation to the bevel gear workpiece 11. This starting position is associated with a first cradle angle. Simultaneously or after reaching the corresponding starting position, the gear cutting tool 10 is rotationally driven around the tool spindle axis A1 of the grinding machine 10 (called rotational velocity 1), in order to reach the required cutting speed. The gear cutting tool 10 can also be continuously rotationally driven from the beginning of the method to the end of the method (at uniform speed or at variable speed) to prevent starting and decelerating multiple times.

[0133] The relative movement can be performed using one or more axes of the gear cutting machine 100.

[0134] The relative movement can be a linear movement or it can follow a curved path. The relative movements can also comprise multiple linear and/or curved movements.

[0135] The preliminary machining phase can optionally comprise a step-by-step plunging into the material of the bevel gear workpiece 11, to reduce the wear on the gear cutting tool 10. In this case, reference is made to a multistage preliminary machining phase.

[0136] The multistage preliminary machining phase can also comprise a change of the rotational velocity 1 of the gear cutting tool and/or a change of the speed of the relative movement(s) to reduce the wear and increase the efficiency of the method.

[0137] As already described, the multistage plunging-rolling method of the preliminary machining phase can be carried out separately for the generation of each tooth gap 13 of the bevel gear workpiece 11, wherein the bevel gear workpiece 11 carries out an indexing rotation around the workpiece spindle axis B of the gear cutting machine 100 in each case, before a further tooth gap 13 of the bevel gear workpiece 11 is generated by the renewed execution of the subprocesses of the multistage preliminary machining phase.

[0138] The subprocesses of the multistage preliminary machining phase can also be carried out in a gap-spanning manner, however.

[0139] While the above describes certain embodiments, those skilled in the art should understand that the foregoing description is not intended to limit the spirit or scope of the present disclosure. It should also be understood that the embodiments of the present disclosure described herein are merely exemplary and that a person skilled in the art may make any variations and modification without departing from the spirit and scope of the disclosure. All such variations and modifications, including those discussed above, are intended to be included within the scope of the disclosure.