Method for mechanical tooth profile grinding

Abstract

The invention relates to a method (1) for mechanical tooth grinding, in particular indexing grinding, of a workpiece (2) having an exit-delimited tooth profile (3.3), comprising the following steps: providing and positioning the workpiece (2), the workpiece (2) comprising an exit-delimited tooth profile (3.3) having at least one first tooth-shaped exit (3.3a). Subsequently, a grinding tool (4), in particular a grinding wheel (4), is set (5) to a set position (6). After the tool setting (5), a feed movement (7, 9) of the grinding tool from the first tool setting position (6) in the direction of the tooth-shaped structure (3.3) towards the first tooth-shaped exit structure (3.3a) at a feed speed corresponding to the initial feed speed is carried out. During the feed speed, the feed speed is then reduced relative to the initial feed speed as soon as the grinding tool reaches a predetermined first deceleration position (8) along the feed movement (7, 9). Subsequently, the feed movement (7, 9) is carried out at a reduced feed speed and finally the grinding tool (4) is retracted (10).

Description

TECHNICAL FIELD

[0001] The present application relates to a method for mechanical tooth grinding, in particular index forming grinding, of a workpiece having a tooth form bounded by an exit portion. BACKGROUND

[0002] Mechanical tooth grinding refers to a method technology which is applied in a workpiece having a tooth form, in particular in the case of a gear blank, in order to grind one or more tooth forms of the workpiece.

[0003] Here, a workpiece refers to a blank which already has a tooth form, in particular milled, which is subsequently further processed into a usable tooth by tooth grinding. Such a workpiece is generally cylindrical-symmetrical in addition to the tooth form.

[0004] In the following, a tooth form refers in particular to at least one structure of the workpiece surface which corresponds to a single gear tooth groove, wherein the gear tooth groove contains a single pitch or one index profile. It in turn generally contains two opposing tooth flanks (correspondingly also with half a tooth tip region) and a root region between the teeth. The tooth form extends on the peripheral surface of the workpiece along the symmetry axis of the workpiece (wheel axis). Here, its curve can also be angled with respect to the symmetry axis, i.e. the helix angle.

[0005] There are different grinding technologies, index forming grinding and continuous generating grinding also belong among them. In index forming grinding, the grinding wheel grinds the single index profile. For this purpose, the grinding wheel is usually indexed to the workpiece, i.e. it is brought from the outside to the workpiece and subsequently grinds along the tooth form of the workpiece in an infeed movement with a certain infeed speed. In order to completely grind all tooth forms of the workpiece, this process must be carried out individually for each tooth form. In contrast, in generating grinding a worm grinding wheel is used which, similar to a worm gear, processes the workpiece by rotating. The worm grinding wheel can also be moved axially infeed here.

[0006] In a workpiece having a tooth form bounded by an exit portion, i.e. a workpiece having a tooth form with a tooth form exit structure, in which the depth of the tooth form, i.e. the tooth height, continuously decreases along the workpiece or along the tooth form, it is in particular an aspect to be noted. By the varying depth along the tooth form, the interaction of the grinding wheel or worm with the workpiece also changes. In particular, by the common curvature of the depth profile of the tooth form exit structure and the grinding tool, the grinding surface becomes larger, whereby the heat input is also increased. As a result, it can lead to grinding burns on the workpiece, in particular in the area of the tooth form exit structure.

[0007] Generally, this is prevented by indexing the grinding tool, in particular a grinding wheel or a worm, at the tooth profile exit structure of the workpiece with a relatively slow indexing speed. The infeed movement is then carried out away from the tooth profile exit structure. This makes it possible that the grinding tool does not generate a heat input in the area of the tooth profile exit structure which would lead to a grinding burn.

[0008] A disadvantage of this approach is that the indexing speed cannot be increased, because this would lead to a higher heat input into the workpiece and in turn to a grinding burn. As a result, the tooth profile grinding of a workpiece having a tooth profile structure limited by an exit portion becomes a very time-consuming process. Another disadvantage is that the infeed movement has to be carried out away from the tooth profile exit structure. This makes the grinding of a tooth profile structure limited by an exit portion on both sides difficult. The existing method is thus less flexible. SUMMARY

[0009] It is the task of the present invention to realize a method which belongs to the aforementioned technical field and which makes it possible to carry out a more flexible mechanical tooth profile grinding of a workpiece having a tooth profile structure limited by an exit portion.

[0010] The solution to this task is defined by the features of claim 1. According to the invention, the method for mechanical tooth profile grinding comprises the following steps: a) providing and positioning a workpiece, wherein the workpiece comprises a tooth profile structure limited by an exit portion having at least one first tooth profile exit structure; b) indexing a grinding tool, in particular a grinding wheel, to an indexing position; c) carrying out an infeed movement with the grinding tool from the indexing position in the direction of the tooth profile structure towards the first tooth profile exit structure with an infeed speed which corresponds to an initial infeed speed; d) starting a reduction of the infeed speed relative to the initial infeed speed as soon as the grinding tool reaches a predetermined first deceleration position along the infeed movement; e) completing the infeed movement with the reduced infeed speed; f) retracting the grinding tool.

[0011] For the purpose of explaining the invention, the following designations are used: "axial" refers to a position, direction or distance parallel to a symmetry axis of the basic shape of the workpiece (not taking into account the tooth profile structure or the tooth profile structures). "Radial" refers to a position, direction or distance perpendicular to this symmetry axis.

[0012] The workpiece mentioned in step a) corresponds to a workpiece as already described in the preamble, i.e. it is preferably substantially cylindrical-symmetrical (apart from the tooth profile structure or the tooth profile structures) and can serve as a gearwheel after production, for example. The tooth profile structure limited by an exit portion corresponds here to the tooth profile structure described in the preamble having a first tooth profile exit structure.

[0013] Positioning comprises a fixation of the workpiece, so that the workpiece does not change its position during the remaining method steps. A rotation about the axis of symmetry can be allowed, especially in methods for generating grinding. In index forming grinding, usually a limited rotation of the workpiece is carried out at most during grinding (for example in the presence of a helix angle, see below).

[0014] The grinding tool according to the method is a grinding wheel, especially for index forming grinding, or a worm grinding wheel, especially for continuous grinding. The use of such grinding tools is known per se.

[0015] The tool setting position is the position into which the grinding tool has to be brought in order to be able to start the infeed movement. In the tool setting, the grinding tool is thus at least partially moved in radial motion from a position further outside the workpiece, for example a maintenance position, to the position of use. The tool setting speed is typically in the range from 1 mm / min (very slow) to 100 mm / min (for example for tool setting positions without the danger of grinding burns).

[0016] The infeed movement is the movement of the grinding tool along the tooth form, thus the substantially axial movement relative to the workpiece, so that the grinding tool and the workpiece interact and the workpiece is ground during the infeed movement. If a grinding wheel is involved, it will be rotated especially during the infeed movement. If the tooth form has a helix angle, the grinding wheel can be oriented in correspondence with the helix angle and perform an axial infeed movement, while the workpiece is rotated in such a way that the grinding wheel stays in the tooth form. Alternatively, the grinding wheel can perform a non-fully axial infeed movement along the tooth, without the workpiece rotating.

[0017] In the continuous grinding process with a worm grinding wheel, not a single tooth form (according to the above definition) is ground individually. Here the workpiece is moved in rotation, whereby the worm grinding wheel can be in mesh with different tooth forms at different points in time during the method. The infeed movement is carried out axially relative to the workpiece.

[0018] According to the invention, the infeed movement is carried out in the direction of the first tooth form exit structure at an infeed speed, that is, an infeed speed corresponding to the initial infeed speed. The infeed speed can have a value of up to 1200 mm / min, for example, however also higher or lower values can be employed.

[0019] As soon as the workpiece reaches the predetermined first deceleration position along the infeed movement, the feed speed is reduced relative to the initial feed speed. A reduction is a decrease in the feed speed, in particular over a certain path of the infeed movement. The first deceleration position of the grinding tool is predetermined, i.e. it has been set before the deceleration position is reached, in particular before the infeed movement, in particular preferably before the workpiece is positioned. In particular, the first deceleration position is selected in the method in a step in which the geometry of the tooth form structure of the workpiece is taken into account. Thereby, a timely reduction of the feed speed can be ensured, even without a simultaneous measurement. Here, the feed speed reduction can be implemented in different ways and with different curves, as will also be set out below.

[0020] The infeed movement and thus the grinding process is completed with the reduced feed speed. In particular, the infeed movement ends when the grinding tool has also ground the outermost portion of the first tooth form exit structure.

[0021] After the infeed movement, in particular a repositioning movement, in particular radial, is carried out for retracting the grinding tool. The repositioning movement is here in particular a radial movement which moves the grinding tool out of engagement with the tooth form structure.

[0022] The grinding tool is thus retracted, in particular after the infeed movement has been completed. Here, the grinding tool, in particular in a radial movement, is again brought to the radial position in which it was before the method was started. The repositioning movement takes place in particular in a rapid stroke, i.e. it is carried out at maximum possible speed and here usually has a speed of approximately 15000 mm / min.

[0023] The reduced feed speed reduces the input of heat into the workpiece during the grinding process, even when the grinding tool is fully engaged in the tooth. This in turn reduces the possible grinding burn to an acceptable extent or completely prevents the occurrence of grinding burn. The reduction of the feed speed in the method according to the application thus allows the infeed movement towards the tooth form exit structure. This in turn has different advantages: If the tool setting position is chosen accordingly, the tool setting can take place at a higher speed. This increases the speed of the method. A further advantage is that the grinding of a workpiece with a double-sided tooth form exit structure is achieved in particular simply (see further below for more details). The reduction of the feed speed is carried out at a predetermined deceleration position and not, for example, triggered by a simultaneous measurement, which makes the method less complex and in turn in particular simple to carry out. The reduction of the feed speed thus generally increases the flexibility of the method.

[0024] In a preferred embodiment of the application, a workpiece is provided in which the tooth form structure continues axially without an exit portion up to a first free end of the workpiece and the tool setting position is axially located outside the first free end of the workpiece and radially at the level of the depth of the tooth form structure at the first free end of the workpiece.

[0025] The first free end of the workpiece here means a portion of the workpiece on which the toothing structure ends (axially) and on which no other portion of the workpiece, for example a journal, is radially above the height level of the toothing structure (or its deepest depth) axially continued beyond the toothing structure. The deepest depth of the toothing structure here means the region of the toothing structure having the smallest radial height inside the toothing structure, in particular the root region or the root line of the toothing structure. The radial height level of the deepest depth of the toothing structure accordingly is in particular the root height of the toothing structure. Axially beyond the first free end here means a position selected in the axial direction such that the grinding tool does not contact the workpiece.

[0026] The advantage of this embodiment of the method is that the grinding tool can be brought to the tool setting position very quickly, since the grinding tool does not interact with the workpiece in the tool setting position and accordingly does not input relevant heat into the workpiece. In particular, in this method variant the tool setting speed is 40 mm / min to 100 mm / min. From this tool setting position, the infeed movement in the direction of the first toothing exit structure can then be started directly. A slow tool setting of the grinding tool towards the workpiece is thus not necessary, so that the toothing grinding can be carried out more quickly without grinding burns reducing the quality of the product.

[0027] Alternatively, the tool setting position can be radially on another level. The grinding tool can for example be tool set to a position having engagement with the toothing structure of the workpiece. However, in this case, provided that the tool setting speed is not adjusted accordingly, grinding burns can occur at the location of the tool setting. A corresponding variant will be dealt with further down in the document.

[0028] In a preferred variant of the above-described embodiment of the method according to the application, the workpiece is positioned vertically in axial orientation, wherein the first free end points downwards and the tool setting position is axially below the workpiece.

[0029] Typically, the machine oil used for cooling the workpiece is conveyed from above to below during the grinding process. When the workpiece is oriented with the free end pointing downwards, the machine oil is thus conveyed counter to the infeed movement of the grinding tool. An effective cooling can thereby be carried out during the method according to the application.

[0030] Alternatively, the workpiece can also be positioned in other ways.

[0031] In a preferred alternative to the above-described method, the workpiece provided comprises a second toothing exit structure axially opposite the first toothing exit structure, wherein the tool setting position is axially on the level of the second toothing exit structure and radially on the level of the depth of the toothing structure at the engagement point of the grinding tool.

[0032] In this method, a workpiece is ground, which has a tooth profile structure comprising a second tooth profile exit structure. Here, the grinding tool is first of all indexed to an indexing position on the second tooth profile exit structure using an indexing speed. In particular, the indexing speed has a value of 1 % to 3% of the typical maximum indexing speed. Preferably, the indexing speed has a value of 1 mm / min to 4 mm / min. The indexing position is axially located in the region of the second tooth profile exit structure and radially at a position which corresponds to the depth of the tooth profile structure at the engagement point of the grinding tool. The depth of the tooth profile structure at the engagement point of the grinding tool means the depth which the tooth profile structure has at the axial position of the indexing position. The grinding tool is positioned in such a way that it can interact with the root region of the tooth profile structure, just as with the rest of the tooth profile structure. In particular, it is positioned in such a way that it contacts the outermost region of the second tooth profile exit structure.

[0033] In particular, the feed speed can be slower during the infeed movement than in the case of a workpiece without a second tooth profile exit structure. In particular, it has an initial value which is about 80% or less of the maximum feed speed within the grinding process, in particular 80% to 20% of the maximum feed speed within the grinding process, preferably 60% to 30%. In particular, the feed speed is accelerated up to the initial feed speed. Here, the acceleration can be stepwise, linear, exponential or follow the depth profile of the second tooth profile exit structure. In particular, the acceleration can also have a different profile than the (subsequent) feed speed reduction (also in time mirrored).

[0034] Alternatively, the feed speed can also already correspond to the initial feed speed at the start of the infeed movement. In particular, the feed speed can also already correspond to the maximum feed speed within the grinding process.

[0035] Then, the feed speed is reduced when a predetermined first deceleration position is reached, in particular before the first tooth profile exit structure is reached.

[0036] This embodiment allows the tooth profile structure of a workpiece to be ground in a temporally efficient manner, which has two opposing tooth profile exit structures.

[0037] In a preferred variant of the application according to all the above-mentioned alternatives, the feed speed is reduced to a final feed speed, wherein the final feed speed is 80% or less of the initial feed speed, in particular 80% to 20% of the initial feed speed, preferably 60% to 30%.

[0038] The final feed speed is understood here to mean the feed speed which the tool feed motion has at the end of the reduction in the feed speed. Here, the feed speed can be reduced to the final feed speed over a short path of the tool feed motion or it has this value, for example, only at the end of the tool feed motion (see below for more details). A reduction in the feed speed to a value of 80% or less of the initial feed speed, in particular 80% to 20% of the initial feed speed, preferably 60% to 30% of the initial feed speed, leads to an effective prevention of grinding burns in the tooth profile exit region in tests.

[0039] Alternatively, the feed speed can also be reduced to a higher or lower value. This can, however, lead to a less effective prevention of grinding burns or a slower method.

[0040] In a preferred embodiment of the application, the feed speed is reduced in steps from the initial feed speed to the final feed speed. By steps is understood here to mean one or more relatively instantaneous reductions in the feed speed. The speed profile of the feed speed along the path of the tool feed motion thus follows a decreasing step function. Preferably, the feed speed is reduced from the initial feed speed to the final feed speed in a single step.

[0041] During a single reduction step, the ratio of the feed speed to the path of the tool feed motion or the length of the tooth profile structure is reduced to the other feed speed value within a relatively very short path interval, in particular in a path interval of 0% to 1% of the tooth profile structure length.

[0042] This variant is less complex and thus simple to monitor and define. One (first) or more reduction positions with a respective final value for the feed speed, for example, can serve as input parameters, wherein the last final value corresponds to the final feed speed. This is also an attractive variant for a study and measurement series, since the individual measurements differ from one another only in a few parameters. If the feed speed is reduced directly from the initial feed speed to the final feed speed, this has the advantage that the reduction instantaneously exerts its full effect. The first reduction position can thus also be chosen at a relatively short distance from the critical region of the tooth profile structure for grinding burns. This in turn ensures an effective method.

[0043] In a likewise preferred alternative to the above-described method, the feed speed is linearly reduced relative to the initial feed speed, wherein, starting from the first reduction position, the feed speed is continuously linearly reduced to the final feed speed via a first reduction path of the tool feed motion up to the reduction end position.

[0044] A linear decrease means that the feed speed substantially follows a linear function along the deceleration path between the first deceleration position and the deceleration end position, wherein the feed speed is reduced with respect to the initial feed speed. In particular, a linear decrease also includes feed speed curves in which the feed speed is implemented non-linearly over a relatively short path section at the edge of the deceleration path. This short non-linear curve in the sense of a gentle reduction of the feed speed can ensure that the acceleration, that is the first derivative of the feed speed curve, does not have jumps. A relatively smooth reduction of the feed speed is thereby achieved.

[0045] The advantage of this variant is a relatively simple curve which can be defined with a few parameters, such as the first deceleration position, the deceleration end position and the final feed speed. At the same time, the feed speed reduction is little or not at all jerky in this variant, which is in turn suitable, for example, for avoiding undesirable vibrations of the grinding tool during the reduction, in particular when the initial feed speed is relatively high.

[0046] In another preferred alternative to the above-described method, the feed speed is reduced exponentially with respect to the initial feed speed, wherein, from the first deceleration position, until the deceleration end position, via the first deceleration path of the infeed movement, the feed speed is reduced to the final feed speed according to a predetermined exponential function, wherein the degree of reduction decreases. This means that the feed speed substantially follows a curve of an exponential function along the deceleration path between the first deceleration position and the deceleration end position. An exponential function here again means a function which has a curve which corresponds to an exponential function for the reduction of the feed speed, wherein the degree of reduction, that is the negative slope of the curve, decreases.

[0047] One possible example is an exponential function of the formula wherein gives the feed speed at the path point begins at and ends at a positive value of . The values and are positive feed speed values, wherein corresponds to the initial feed speed and corresponds to a feed speed value which is lower than the final feed speed. The same positive value is a calibration value which influences how steeply the feed speed converges with respect to the feed speed value . In particular, the reduction of the feed speed can differ from the exponential formula at the beginning of the deceleration, in particular over a relatively small part of the deceleration path, in particular less than 10% of the deceleration path, in order to avoid, for example, a jerky feed speed change.

[0048] The advantage of this type of method is that no acceleration jumps of the feed speed occur during the relatively strongly varying reduction in the deceleration path, whereby vibrations are reduced.

[0049] In a further preferred variant of the method, the feed speed is reduced in a manner corresponding linearly scaled to the curve of the tooth profile depth of the first tooth profile exit structure relative to the initial feed speed, wherein, starting from the first deceleration position, the feed speed of the infeed movement is reduced to the final feed speed in accordance with the curve of the tooth profile depth.

[0050] In this variant, the feed speed is reduced in accordance with a curve which corresponds to the curve of the tooth depth within the tooth profile exit structure. Here, the deceleration path is again the path between the first deceleration position and the deceleration end position. "Linearly scaled" means that the shape of the reduction, although corresponding to the shape of the tooth profile depth, can be scaled with a fixed value proportionally to the latter. This scaling thus allows a freely adjustable final feed speed to be achieved. Even in this type of method, the total reduction is definable in advance. The curve of the tooth profile depth is in particular known at the latest before the reduction begins. The first deceleration position can in particular be chosen such that the deceleration path corresponds to the length of the tooth profile exit structure. However, the reduction can also already begin not far before this length, for example over a distance of less than 10% of the deceleration path, and then follow the curve of the tooth profile depth once the remaining path corresponds to the length of the tooth profile exit structure.

[0051] The advantage of this method is that the reduction of the feed speed matches the actual shape of the tooth profile. Also, the reduction of the feed speed is not applied particularly strongly, whereby initial vibrations of the grinding tool during the reduction of the feed speed are avoided.

[0052] In a preferred variant of all the above-mentioned embodiments of the method according to the application, the first deceleration position is chosen such that the reduction of the feed speed begins before the tooth profile exit structure of the workpiece is reached.

[0053] "Before the tooth profile exit structure is reached" in this case means that the first deceleration position is in a region which lies within the path of the infeed movement before the tooth profile exit structure, that is to say a region in which no point of the grinding tool lies at the same axial height as the first tooth profile exit structure. In particular, the first deceleration position is chosen such that it triggers the reduction before the tooth profile exit structure is reached for a certain workpiece type, preferably also for different workpiece types.

[0054] The advantage of this variant of the method is that the reduction is ensured by the reduction that the grinding tool has already begun in the region of the first tooth profile exit structure.

[0055] In a preferred variant of all the above-mentioned embodiments of the method according to the application, the workpiece is cooled by oil cooling, characterized in that, in addition to the reduction of the feed speed, the oil pressure of the oil cooling of the workpiece is also increased.

[0056] Oil cooling here means the process cooling by means of cooling oil, in particular cooling emulsion. Here, the process heat is discharged in that the cooling oil is fed, in particular sprayed, into the grinding region by means of a supply device, for example a nozzle. This discharge of heat can also influence the formation of grinding burns. The oil pressure here means the pressure which the cooling oil has at the outlet of the supply device.

[0057] In this variant of the method, the workpiece and the grinding tool are cooled by the input of cooling oil into the grinding region. In order to also more effectively prevent the formation of grinding burns in the region of the tooth profile exit structure, in addition to the reduction of the feed speed, the oil pressure is also increased. The oil pressure here influences the amount of cooling oil which is fed into the grinding region, wherein a higher pressure means more cooling oil. The cooling power of the oil cooling is thus increased in a targeted manner.

[0058] The advantage of this embodiment is that the targeted increase in the cooling power of the oil cooling, in particular in the region of the tooth profile exit structure, contributes to the prevention of grinding burns. The reduction of the feed speed can thus be made smaller and the method becomes more time-efficient.

[0059] In a preferred embodiment of the application, the tool approach speed has a value in the range of 40 mm / min to 80 mm / min. In particular, this is a preferred embodiment of the alternative, in which the tool approach position is axially located beyond the first free end of the workpiece and radially at the level of the depth of the tooth profile structure at the first free end of the workpiece. The tool approach speed is thus significantly faster, in particular by a factor of 10, than the typical tool approach speed at the position of the engagement with the tooth profile structure. In the method according to the application, the reduction of the feed speed can in particular be relatively small (compared to the initial feed speed) compared to a possible reduction of the tool approach speed from such a fast tool approach speed to a tool approach speed which does not lead to grinding burns when engaging.

[0060] The relatively fast tool approach speed increases the time efficiency of the method without the threat of grinding burns.

[0061] Also with respect to this alternative of the method, in which the provided workpiece comprises a second toothed exit structure axially opposite the first toothed exit structure, such a fast tool approach speed can increase the efficiency of the method. However, in this variant, the tool approach speed should be reduced before the meshing and, in particular, significantly slower after the tool approach speed is reduced, so as not to cause grinding burns. It can also be necessary in this variant that the reduction is carried out sufficiently far from the workpiece, so that vibrations at the time of the tool approach speed reduction do not cause damage on the workpiece.

[0062] Alternatively, the tool approach speed can also take other, in particular slower, values.

[0063] In a preferred variant of the application according to all the alternatives described, the initial feed speed has a value in the range of 500 mm / min to 1300 mm / min. The initial feed speed thus chosen is relatively fast, whereby the method becomes very efficient.

[0064] Alternatively, the initial feed speed can also have other values, in particular slower. However, this would make the method less efficient.

[0065] In a preferred embodiment of the application, the method comprises the additional step of determining the first deceleration position taking into account the grinding tool diameter, in particular the diameter of the grinding wheel.

[0066] Here, the grinding tool diameter is, for example, the maximum diameter of the grinding tool transversely to the axis about which the grinding tool is able to rotate. In particular, if the grinding tool is a grinding wheel, the grinding wheel diameter is meant.

[0067] Since the first deceleration position is predetermined, the efficiency of the method and the quality of the result depend on the choice of the first deceleration position. The effect of the grinding tool on the workpiece, in turn, depends on the grinding tool diameter. For example, at a relatively large diameter, the grinding tool has a smaller curvature on its grinding surface. This, in turn, makes its grinding effect on the workpiece more planar, that is, less local. Conversely, a grinding tool with a relatively small diameter has a more local or more point-like grinding effect.

[0068] If this is taken into account in the choice of the first deceleration position, the occurrence of grinding burns can be effectively prevented and the method designed more efficiently. The first deceleration position can be positioned, for example, particularly close to the toothed exit structure, without the planar effect of the grinding tool leading to grinding burns.

[0069] In particular, the first deceleration position can be chosen so that the deceleration path corresponds to the length of the grinding wheel radius and, in turn, to half the grinding tool diameter.

[0070] Alternatively, the first reduction position can also be determined, for example, without taking into account the grinding tool diameter. However, in this case, greater safety tolerances must be observed, whereby the method becomes less efficient.

[0071] Further advantageous embodiments and combinations of features of the application result from the following detailed description and the overall patent claims. BRIEF DESCRIPTION OF DRAWINGS

[0072] The drawings used to illustrate the embodiments show:

[0073] Figure 1 An isometric top view based on a first gear blank shows a schematic diagram of the first method of the application,

[0074] Figure 2 A cross-sectional view based on a gear blank shows a schematic diagram of the first method, wherein the gear blank is cut at a plane located centrally of the toothed structure and extending parallel to its depth,

[0075] Figure 3A An X-Y diagram based on the first feed speed curve of the application, wherein the feed speed is reduced in steps,

[0076] Figure 3B An X-Y diagram based on the second feed speed curve of the application, wherein the feed speed is reduced linearly,

[0077] Figure 3C An X-Y diagram based on the third feed speed curve of the application, wherein the feed speed is reduced exponentially,

[0078] Figure 3D An X-Y diagram based on the fourth feed speed curve of the application, wherein the feed speed is reduced in a curve following the depth profile of the toothed exit structure linearly scaled, shown together with a cross-sectional view of the gear blank,

[0079] Figure 4 An isometric top view based on a second gear blank having a toothed structure comprising two toothed exit structures shows the second method of the application, and

[0080] Figure 5 A cross-sectional view based on the second gear blank shows a schematic diagram of the second method, wherein the second gear blank is cut at a plane located centrally of the toothed structure and extending parallel to its depth.

[0081] Principally identical parts in the drawings are provided with the same reference numerals. DETAILED DESCRIPTION

[0082] Figure 1 and Figure 2 A schematic diagram showing a method 1 for index-forming grinding of a gear blank 2 according to the application.Figure 1 This method 1 is illustrated here based on a schematic isometric top view of the gear blank 2. Figure 2 Method 1 is illustrated based on a partial cross-section of the gear blank 2. The gear blank 2 is generally cylindrically symmetrical and includes a similarly cylindrically symmetrical journal 2.1. Adjacent to the journal 2.1, the gear blank 2 includes tooth profiles evenly distributed around its circumference. Figure 1 The tooth-shaped structures 3.1, ..., 3.5 are visible in the image. These tooth-shaped structures 3.1, ..., 3.5 include groove-shaped recesses extending parallel to the cylindrical axis of the gear blank 2 on its surface. Therefore, the tooth-shaped structures 3.1, ..., 3.5 do not have a helix angle. The area between these recesses constitutes the tooth portion of the gear blank 2. The tooth-shaped structures 3.1, ..., 3.5 each have a length approximately equivalent to half the length of the gear blank 2 (in... Figure 1 and Figure 2 (The middle is vertical).

[0083] The depth profile of tooth structure 3.3 is in Figure 2 As can be seen, it shows a partial cross-section of the gear blank 2 at a plane that is centrally located within the tooth structure 3.3 and extends parallel to the depth of the tooth structure 3.3. The depth of the tooth structures 3.1, ..., 3.5 remains constant for approximately 60% of their respective lengths from the free end. Within the remaining 40% of this length, the tooth structures 3.1, ..., 3.5 include tooth exit structures 3.1a, ..., 3.5a. In these regions, the depth of the respective tooth structures 3.1, ..., 3.5 decreases along their length with a constant radius of curvature until the depth completely exits.

[0084] In method 1, the gear blank 2 is positioned such that it is fixed during the grinding process. Here, the gear blank 2 is vertically oriented along its axis of symmetry (in... Figure 1 and Figure 2 The figure is vertical in the attached plane, with the free end pointing downwards. Grinding is performed using a grinding wheel 4 in method 1, the radius of which corresponds to the radius of curvature of the tooth exit structures 3.1a, ..., 3.5a. During a tool-setting motion at 60 mm / min, the grinding wheel 4 is set to the first tool-setting position 6. Here, the tool-setting position 6 is located axially below the gear blank 2. Radially, the tool-setting position 6 is located at the level of the root region of the tooth structure 3.3 at the end of the gear blank, that is, at the level of the deepest depth of the tooth structure 3.3 (see Figure 1). Figure 2 ).

[0085] After the tool setting motion 5 is completed and reaches the tool setting position 6, the grinding wheel rotates into the tooth profile 3.3 in the initial feed motion 7 and grinds the tooth profile 3.3 there. Here, the grinding wheel rotates in a reverse grinding manner with respect to the feed motion. The initial feed motion 7 is carried out here with an initial feed rate of 600 mm / min and extends parallel to the length of the tooth profile 3.3.

[0086] Along the entire feed motion, starting from the predetermined deceleration position 8, the feed rate begins to decrease, and then the feed motion proceeds to deceleration position 9. The deceleration position 8 is predetermined based on the curve of the grinding wheel diameter and the tooth exit structure 3.3a: such that the feed rate is reduced before reaching the tooth exit structure 3.3a, and at deceleration position 8, the grinding wheel does not contact the area where the depth has been reduced (i.e., the tooth exit structure 3.3a). During the deceleration feed motion 9, the feed rate is reduced to a final feed rate, which is 50% of the initial feed rate.

[0087] In this embodiment of the invention, the feed rate decreases linearly (see below). Figure 3B Here, other deformation schemes for reduction are discussed. Figure 3A , Figure 3C and Figure 3D As shown in the diagram (see below for further details). The feed motion 9 ends when the grinding wheel 4 contacts the outermost part of the tooth profile exit structure 3.3a. At the end of the entire feed motion, the grinding wheel 4 retracts 10 at a retraction speed of 15,000 mm / min. After the retraction 10 ends, a return motion 11 is performed to return the grinding wheel to its starting position at a return speed of approximately 700% of the initial feed rate. Cooling oil is supplied 12 during the grinding process. To grind other or all tooth profiles 3.1, ..., 3.5, method 1 must be repeated multiple times, wherein the gear blank 2 rotates about its axis of symmetry at the point when the grinding wheel 4 is not engaged, so that other tooth profiles 3.1, ..., 3.5 can be ground.

[0088] Figures 3A to 3D Different feed rate profiles are schematically shown, which are based on the method of the invention (e.g., according to...). Figure 1 and Figure 2 Method 1 or based on from Figure 4 and Figure 5 Method 401 is possible. Here, Figure 3A This illustrates a stepped feed rate reduction. Figure 50 shows the Y-axis 50Y, which describes the feed rate values. The X-axis 50X shows the respective positions of the grinding wheels relative to the tool setting positions at the origin (e.g., ...). Figure 1 and Figure 2The axial distance of the tool setting position 6) is shown, and the respective positions along the feed motion are also indicated. Feed rate stages 51, 52, 53, 54, and 55 illustrate the feed rate along the feed motion. In a relatively short acceleration phase, the feed rate increases to the initial feed rate via feed rate stage 51. From the initial feed rate, the feed rate remains constant in feed rate stage 52.

[0089] From reaching the predetermined deceleration position 56 (e.g.) Figure 1 and Figure 2 From deceleration position 8), the feed rate decreases to the final feed rate via feed rate stage 53. Deceleration position 56 is selected such that the feed rate begins to decrease approximately 60% of the total feed motion. Here, feed rate stage 53 extends a short distance within the feed motion and is therefore stepped. The final feed rate is 50% of the initial feed rate. In feed rate stage 54, the final feed rate remains constant until the end of the grinding process. After the grinding process ends at feed rate endpoint 57, the feed rate decreases to zero according to feed rate stage 55.

[0090] Figure 3B This shows a decrease in linear feed rate. The X-axis 150X and Y-axis 150Y in Figure 150 correspond to... Figure 3A The X and Y axes. In this XY diagram 150, feed rate stages 151, 152, 153, 154, and 155 illustrate the feed rate along the infeed motion. Again, via feed rate stage 151, the feed rate increases to the initial feed rate in a shorter acceleration. Feed rate stage 152 also corresponds to... Figure 3A The feed rate stage 52.

[0091] Upon reaching the predetermined deceleration position 156, the feed rate begins to decrease linearly according to the feed rate phase 153, proceeding along a certain deceleration path until a final feed rate is reached at the deceleration endpoint position 158, where the final feed rate is 50% of the initial feed rate. The deceleration position 56 is selected such that the feed rate begins to decrease at approximately 60% of the total feed motion. The final feed rate is then maintained at feed rate phase 154 until the feed rate endpoint position 157, which constitutes approximately 11% of the total feed motion. Thereafter, it decreases to zero via a shorter path through feed rate phase 155.

[0092] Figure 3C This shows a decrease in the exponential feed rate. The X-axis 250X and Y-axis 250Y of Figure 250 correspond to... Figure 3A and Figure 3B The X and Y axes. Feed rate stages 251 and 252 until the predetermined deceleration position 256 corresponds to... Figure 3A andFigure 3B The feed rate phase of the implementation scheme. From deceleration position 256 to the deceleration end position 258, feed rate phase 253 follows the formula: The exponential function. Here, In position The feed rate at that location, where, It has a zero value at deceleration position 256. Specify the initial feed rate value, and It is a positive calibration value, which is selected such that: It has a value at the point where deceleration ends. This is the final feed rate, which is 50% of the initial feed rate. From the deceleration endpoint position 258, the feed rate remains constant at the final feed rate during feed rate phase 254. From the feed rate endpoint position 257, the feed rate then decreases to zero relatively quickly.

[0093] Figure 3D The feed rate decreases, linearly scaling to follow the depth profile. The XY diagram 350 shows the X-axis 350X and Y-axis 350Y corresponding to... Figures 3A to 3C The XY diagrams are 50, 150, and 250. The initial feed rate stages 351 and 352 are also similar to other embodiments ( Figures 3A to 3C For visual illustration, a cross-section of a workpiece 302 with toothed structure 303.3 and toothed exit structure 303.3a is shown here, similar to that according to... Figure 2 The cross-section. Furthermore, schematic diagram 350S shows the positions of the grinding tool at the deceleration position 356 and the feed rate endpoint position 357.

[0094] From deceleration position 356, the feed rate decreases. Here, the feed rate stage 353 corresponds in shape to the depth profile of the toothed exit structure 303.3a and is multiplied by a corresponding linear scaling factor. Thus, the feed rate decreases from the initial feed rate to the final feed rate, where the initial feed rate dominates at deceleration position 356. Deceleration position 356 is chosen such that the grinding tool travels a distance corresponding to the extension length of the toothed exit structure 303.3a until the feed rate endpoint 357 (see schematic diagram 350S). The feed rate endpoint 357 is reached again when the grinding tool contacts the outermost region of the toothed exit structure 303.3a.

[0095] Therefore, the feed rate curve in the feed rate stage 353 has the same curve as the tooth depth of the tooth exit structure 303.3a: for example, after traveling the same distance required for the tooth depth to drop to half, the feed rate after the deceleration position 356 is reduced to the feed rate value located between the initial feed rate and the final feed rate.

[0096] When the grinding tool has reached the feed rate endpoint 357, the feed rate has a final feed rate value, which is 50% of the initial feed rate. From the point of reaching the feed rate endpoint 357, the feed rate then decreases to zero relatively quickly in feed rate phase 354.

[0097] Figure 4 and Figure 5 Method 401, as another embodiment of the present invention, is shown. Here, Figure 4 A schematic isometric top view of the provided gear blank 402, having journal 402.1, shows method 401. The gear blank 402 includes uniformly distributed and identically shaped tooth profiles on its circumference. Figure 4 The tooth profiles 403.1, ..., 403.5 are visible. The tooth profiles 403.1, ..., 403.5 are oriented parallel to the axis of symmetry of the gear blank 402 and have a length approximately 80% of the length of the main body of the gear blank 402 without the journal 402.1 along the axis of symmetry of the gear blank 402. Each tooth profile 403.1, ..., 403.5 includes two opposing tooth exit structures: a first tooth exit structure 403.1a1, ..., 403.5a1 and a second tooth exit structure 403.1a2, ..., 403.5a2.

[0098] The resulting depth profile Figure 5 As can be seen in: Figure 5 The method 401 is illustrated based on a schematic cross-section of the provided gear blank 402, wherein the gear blank 402 is cut at a plane that is centrally located within the tooth profile 403.3 and extends parallel to its depth. The depth of the tooth profile 403.3 is centrally located and remains constant and is maximum at approximately 60% of its length. Tooth exit structures 403.3a1 and 403.3a2 are located at the two longitudinal ends of the tooth profile 403.3. Within each tooth exit structure 403.3a1 and 403.3a2, the depth gradually decreases to zero continuously (and following a continuously differentiable curve) toward the end of the tooth profile 403.3.

[0099] The gear blank 402 is vertically positioned such that its journal points upward and its free end points downward. Then, the grinding wheel 404 is set to the setting position 406 at a setting speed of 1.5 mm / min during the setting motion 405. The grinding wheel 404 has already rotated during the setting motion 405.

[0100] The tool setting position 406 is axially located on the gear blank 402, at the tooth exit structure 403.3a2, and radially located at the depth of the tooth exit structure 403.3 at the meshing point of the grinding wheel 404. Here, its position is such that the grinding wheel contacts the outermost region of the tooth exit structure 403.3a2 at the tool setting position 406.

[0101] After tool setting, a feed motion 407 with a feed rate of 600 mm / min is performed. The feed motion 407 is performed along the tooth profile 403.3, which is ground by a grinding wheel 404.

[0102] The deceleration position 408 is located before the first tooth exit structure 403.3a1 along the feed motion. After reaching the deceleration position 408, a deceleration feed motion 409 is performed, in which the feed rate is reduced to a final feed rate, which is 50% of the previous feed rate. The deceleration curve is stepped in this case. However, it can also be similar to... Figures 3B to 3D One of the feed rate curves shown. The feed motion 409 ends when the grinding wheel 404 contacts the outermost part of the tooth retraction structure 403.3a1. After the entire feed motion is completed, the grinding wheel 404 is retracted 410 at a retraction speed of 15000 mm / min. After the retraction 410 is completed, a return motion 411 is performed to return the grinding wheel 402 to its starting position at a return speed of approximately 700% of the maximum feed rate. Cooling oil is supplied 412 during the grinding process, wherein the cooling oil is sprayed into the grinding area through a nozzle. To grind other or all tooth structures 403.1, ..., 403.5, method 401 must be repeated multiple times.

[0103] This invention is not limited to the aforementioned embodiments or variations. For example, a workpiece with more or fewer teeth can be provided. The workpiece does not necessarily include a journal, or it may include a journal with a different shape. The shape of the workpiece can be different from the shape shown. For example, the workpiece can have different diameters at different locations along the workpiece axis. For example, a workpiece can also be provided that is longer along the workpiece axis than its diameter.

[0104] These tooth-like structures can be deeper and longer, or shallower and shorter, compared to the tooth-like structure shown. The tooth depth shown can have different curves and, for example, gradually decrease to zero with a small curvature at the tooth exit structure.

[0105] The grinding tool can also be a worm wheel, which is used in continuous grinding methods. The grinding tool used may have an extension length different from the extension length shown (illustratively), and may have, for example, a larger or smaller diameter.

[0106] The workpiece can be positioned in other ways, such as vertical with the journal pointing downwards, or not vertical but inclined relative to the vertical axis. The speed values ​​for tool setting, reset, feed, and return motions are purely illustrative and can be chosen differently. The first deceleration position can also be another deceleration position, for example, positioned such that it has already caused deceleration from the halfway point of the entire feed motion. Positions outside the workpiece are shown purely schematically and can be located further away from or closer to the workpiece. Oil cooling can also differ from the schematic view shown.

[0107] The slope of the feed rate curves shown, as well as the relative values ​​of the initial and final feed rates, can vary. For example, a linear decrease can extend more steeply, with the final feed rate being only 40% of the initial feed rate. With a linear decrease, it is not necessary to continue the feed motion at the final feed rate. With a stepped decrease, more than one stepped decrease can also be implemented. An exponential decrease can be implemented more steeply or more gently. Optionally, a constant feed rate phase can also follow the exponential decrease.

[0108] The toothed structures shown, each with two toothed exit structures, can also have other shapes and, for example, different depth profiles. In addition to the radial tool setting motion, other motion components may exist to feed the grinding tool to the first tool setting position along a more complex path.

[0109] When the feed rate follows the decrease in depth profile in a linear, exponential, or linear scaling manner, the feed rate profile can also be different at the transition point (immediately after the deceleration position or immediately before the end of deceleration) so that the feed rate follows a continuously differentiable curve (without sudden acceleration changes).

[0110] In summary, it can be determined that a grinding method is achieved by reducing the feed rate, which makes it possible to perform more flexible mechanical tooth grinding on workpieces with tooth profiles limited by the exit section.

Claims

1. A method for mechanical tooth profile grinding, especially indexing profile grinding, on a workpiece having a tooth profile structure limited by a withdrawal section, comprising the following steps; a) Providing and positioning a workpiece, wherein the workpiece includes a toothed structure having at least one first toothed exit structure and being limited by an exit portion; b) Position the grinding tools, especially the grinding wheel, to the tool setting position; c) The grinding tool is moved from the tool setting position along the tooth structure toward the first tooth exit structure at a feed rate equivalent to the initial feed rate; d) Once the grinding tool reaches the predetermined first deceleration position along the feed motion, it begins to reduce the feed rate relative to the initial feed rate; e) The feed motion is completed at a reduced feed rate; f) Retract the grinding tool.

2. The method according to claim 1, wherein, A workpiece is provided in which a toothed structure extends axially without a retraction portion to a first free end of the workpiece, and wherein the tool setting position is axially located outside the first free end of the workpiece and radially located at the level of the depth of the toothed structure at the first free end of the workpiece.

3. The method according to claim 2, characterized in that, The workpiece is vertically positioned in the axial orientation, wherein the first free end points downward and the tool setting position is axially located below the workpiece.

4. The method according to claim 1, characterized in that, The provided workpiece includes a second toothed exit structure that is axially opposite to the first toothed exit structure, wherein the tool setting position is axially located at the level of the second toothed exit structure and radially located at the level of the depth of the toothed structure at the meshing point of the grinding tool.

5. The method according to any one of claims 1 to 4, characterized in that, The feed rate is reduced to a final feed rate, wherein the final feed rate is 80% or less of the initial feed rate, particularly 80% to 20% of the initial feed rate, preferably 60% to 30%.

6. The method according to claim 5, characterized in that, The feed rate is reduced stepwise from the initial feed rate to the final feed rate.

7. The method according to claim 5, characterized in that, The feed rate is linearly reduced relative to the initial feed rate, wherein, starting from the first deceleration position and continuing until the deceleration endpoint position, the feed rate is continuously and linearly reduced to the final feed rate via the first deceleration path of the feed motion.

8. The method according to claim 5, characterized in that, The feed rate is reduced exponentially relative to the initial feed rate, wherein, starting from the first deceleration position and continuing until the deceleration endpoint position, the feed rate is reduced to the final feed rate according to a predetermined exponential function via the first deceleration path of the feed motion, wherein the degree of reduction is diminished.

9. The method according to claim 5, characterized in that, The feed rate is reduced relative to the initial feed rate in a manner that linearly scales the curve corresponding to the tooth structure depth of the first tooth exit structure, wherein, starting from the first deceleration position, the feed rate of the infeed motion is reduced to the final feed rate according to the curve of the tooth structure depth.

10. The method according to any one of claims 1 to 9, characterized in that, The first deceleration position is selected such that the reduction in the feed rate begins before reaching the toothed exit structure of the workpiece.

11. The method according to any one of claims 1 to 10, wherein, The workpiece is cooled using oil cooling, characterized in that, in addition to reducing the feed rate, the oil pressure for oil cooling of the workpiece is increased.

12. The method according to any one of claims 1 to 11, wherein, The tool setting speed has a value in the range of 40 mm / min to 80 mm / min.

13. The method according to any one of claims 1 to 12, wherein, The initial feed rate has a value in the range of 500 mm / min to 1300 mm / min.

14. The method according to any one of claims 1 to 13, the method comprising the additional step of determining the first deceleration position taking into account the diameter of the grinding tool, especially the diameter of the grinding wheel.

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