EP3022014B1 - Method for the centreless grinding of shaft parts, in particular of tubes for assembled camshafts - Google Patents

Description

The invention relates to a method for centerless grinding of shaft parts, in particular of tubes for built camshafts, wherein the shaft parts to the workpiece longitudinal axis concentrically extending end-side centering holes have.

Typically, in centerless grinding, the workpiece between the grinding wheel and regulating wheel is ground resting and rotating on a support ruler. Regulating wheel and grinding wheel thereby form a grinding gap which is closed down by the support ruler so far that the wave-shaped workpiece is enclosed by a linear contact with the regulating wheel, the grinding wheel and the support surface of the support ruler and is thus fixed in position with respect to its longitudinal axis and rotated. The aim of this arrangement is a quiet as possible position despite rotation and runout of the rough blank.

As a rule, the blank to be ground is subject to pre-processing before it is finished. After roughing, the blank has dimensional errors, in particular straightness errors or rounding errors. If such a workpiece with straightness errors is subjected to a centerless grinding process, the workpiece is first ground at the location of the highest concentricity impact. Because of such form errors, the workpiece is not exactly on the support ruler when grinding. Only after the complete grinding of the workpiece will this rest in the grinding gap substantially full length on the support ruler and can - if at all - now defined and cut to size and shape.

Often, in the course of pre-machining, centering is introduced on each end face of the workpiece to be ground, which is also referred to as the center. This centering is intended to define the longitudinal axis of the finished workpiece, to which the intermediate and finish machining subsequent to the pre-processing should relate. If now the workpieces with Dimensional and shape errors from the processing are ground with conventional centerless grinding, so these errors in the edition or a non-longitudinal complete edition of the workpiece when grinding it is always transferred to the finished part in general. The aim of centerless grinding, however, must be that the existing centers on the workpiece after grinding should be arranged concentrically or deviate from this concentricity only in very narrow tolerances. With the known centerless grinding, it is not possible to guarantee a good concentricity of the centers after grinding when grinding. This results because of the above-mentioned problems on the one hand by the faulty support of the workpiece on the support rail and the other by the manufacturing inaccuracies of the workpiece from the pre-processing.

In a centreless grinding borrowed method described in DD 570, the workpiece abuts in a prismatic groove through a linear contact present on each leg of the support prism and is held in the central region by a pinch roller and pressed into the prism. The known grinding method describes the grinding of two pin-like end portions of the workpiece. The pins can only have sufficient concentricity if the workpiece has previously been ground exactly concentric, d. H. just can not be left in its rough contour. The pins present in the end area are ground by means of a grinding wheel without an abutment on the side opposite the grinding wheel. The concentricity accuracy required today can not be achieved with such a method.

In DD 119 009 a workpiece holder for a centerless grinding of cylindrical parts is described in which in a known manner a grinding gap by a grinding wheel, regulating wheel and a support ruler is defined. In the grinding gap, a very long cylindrical rod body is ground by passage grinding. So that a high concentricity or cylindricality of the rod-like round rod to be ground is achieved, the support is mounted hydrodynamically on the support ruler by pockets or nozzles arranged there, which are acted upon by a pressure medium. The pressurization is controlled depending on the load during the respective grinding phase. Thus, a possibly resulting from the pre-processing out-of-roundness or roundness with respect to its influence on the grinding process can be minimized, with straightness errors, which result from the pre-processing, this method should not achieve the desired accuracy.

In DE 103 08 292 B4 are a method for cylindrical grinding in the manufacture of tools made of hard metal and a cylindrical grinding machine for grinding of cylindrical starting bodies described in the manufacture of carbide tools. The tool is guided from endless, guided by a chuck of the workpiece headstock carbide in the tailstock in the top. Although this method is not a centerless grinding, nevertheless, attempts are made in this known method to achieve the highest possible straightness and the lowest possible rounding after grinding, even with rod-like material. However, this is achieved in that after clamping a steady rest ground and that only after successful support to the ground steady seat a cylindrical grinding of a, the leading, end portion of the rod-like material is ground. The method works so "from the running rod".

In DE 10 2010 010 758 A1 A method for centerless cylindrical grinding of rod-shaped workpieces and a centerless cylindrical grinding machine for grinding such workpieces are described. In this known method, a plurality of individual control discs and grinding wheels with an axial distance alternately one behind the other, ie staggered, arranged, with such an axial distance that alternately the respective grinding wheels in the distance between opposing control discs or a respective control disc in the axial distance opposite Grinding wheels intervene. By such an alternating arrangement, a deflection of the shaft part to be ground is to be minimized. Moreover, the individual grinding wheels are arranged so that the grinding gap gradually becomes narrower in the direction of exit from the grinding device. The cylindrical outer contour is thus ground through a peel grinding through the respective individual grinding wheels. The width of the regulating wheels and the grinding wheels is significantly less than the length of the workpiece to be ground in this known cylindrical grinding machine. By the described alternating arrangement, the entire workpiece length is ground simultaneously. A targeted grinding takes place by means of a pre-centering device, which is arranged in the direction of passage of the workpiece to be ground at the entrance. A concentric grinding of end regions for the purpose of centering the blank with respect to the centers is not described in this known method. Rather, a support disk is provided at the input and at the output of the device, which serve the balance of forces because of the staggered and thus unevenly acting grinding wheels. So that this balance of forces can also be realized, it is necessary that on the one hand, the width of the regulating wheel is greater than the width of the grinding wheel and that on the other hand, the respective spindle for the regulating wheels and for the grinding wheels are dimensioned strong and a small axial gap between the Overlap areas of regulating wheel and grinding wheel must be realized.

The US 3 418 763 A1 describes a method for maintaining the concentricity of existing centering in shaft parts in centerless grinding, in which the sanding, on his End faces axial centering having shaft part is ground rotationally driven at a distance between the grinding wheel and regulating wheel.

Mikrosa is known as a manufacturer of centerless grinding wheels. It uses a method in which between so-called auxiliary tips the workpiece is ground and then after the loosening of the tips the workpiece in the same grinding station centerless on a support rail resting between the grinding wheel and the regulating wheel is finished. Both the technical structure and the alignment of the tips require a relatively large effort, and the complete system is difficult to control in terms of accuracy.

In contrast, the object of the present invention is a method for centerless grinding of shaft parts, in particular of tubes for built camshafts, with which form error of a Wellenrohteils from the pre-processing to a much lesser extent affect the accuracy of the finished shaft part, than that in known The method is the case, therefore, therefore, a higher accuracy of the finished ground shaft part can be achieved.

This object is achieved by a method having the features according to claim 1. Advantageous developments are defined in the dependent claims.

In the method according to the invention, in particular camshaft tubes are to be ground so that only a minimal concentricity error occurs, namely, such a high concentricity should be achieved, which can not be achieved with known centerless grinding methods.

The basic idea on which the present invention is based is that the shaft part to be ground is first sanded at its ends in the centerless grinding method, without the grinding and regulating disks already grinding at the points of the highest concentricity of the wave-shaped part. This makes it possible for the shaft part to be ground first in the area in which centerings are found. This ensures that the grinding zones of the shaft part are located exactly above the center, d. H. the respective centering at the ends of the shaft part, so that with respect to the respective center a centric grinding of the shaft part can be achieved, so that at the ends of the shaft part, a high concentricity of the shaft part is achieved.

In the method according to the invention for centerless grinding of shaft parts, which are in particular tubes for built-up camshafts, are, as is usually the case in centerless grinding takes place, to be ground shaft parts, which have axial centering on their front sides, ground between a grinding wheel and a regulating wheel driven in rotation. The grinding wheel and the regulating wheel have a width which corresponds at least to the length of the shaft part. This means that the grinding wheel and the regulating wheel have a width which corresponds at least exactly to the length of the shaft part. However, it is even common that the width of the grinding wheel in the regulating wheel is slightly larger than the length of the shaft part. In conventional arrangement in centerless grinding of shaft parts, the grinding wheel and the regulating wheel in the radial direction at a radial distance from one another in the region of the ends of the shaft part, which is less than in the region between the end portions of the shaft part, ie in the so-called. The required for grinding the shaft part grinding gap is thus - seen in the axial direction of the grinding wheel and the regulating wheel - defined between the grinding wheel and the regulating wheel and is bounded below by a support ruler. The distance between the grinding wheel and the regulating wheel in the radial direction is less in the region of the ends of the shaft part than the distance in the intermediate region between the end regions of the shaft part. As a result, the end portions of the shaft part are first ground. This is followed by the grinding of the intermediate region located between the end regions, followed by a dimensionally and form-wise grinding of the entire shaft part to final dimension, on the basis of concentric with the centering, resting on a support ruler poles at the end portions of the shaft portion. After the end portions have been ground, the dimensional and shape-retaining grinding of the entire shaft part joins, which on the basis of the concentric to the centerings polished on the end portions of the shaft part even with normally always present rounding at elongated wave-shaped components thereby to a higher concentricity leads to the centerings at the end areas, as is the case with conventional centerless grinding.

Radial distance between the grinding wheel and the regulating wheel is not necessarily the smallest distance in the radial direction between the regulating wheel and the grinding wheel understood, but a distance above and below both longitudinal axes of the grinding wheel and the regulating wheel having plane in which arranged the wave-shaped workpiece and is held down by the support ruler in the grinding gap. The geometric relationships for such Centerless loops are in a basic arrangement in Fig. 7 shown. The position of the plane above or below is defined by whether it is ground above or below the center.

According to a first embodiment, the grinding wheel and the regulating wheel are formed so that on their sides, which during grinding of the shaft part of its end portions correspond, are profiled and have a larger diameter than in the lying between the end regions intermediate area. Due to the respective larger diameter in the areas corresponding to the end portions of the shaft part, a smaller distance between grinding wheel and regulating wheel is present than in the intermediate region, so that during grinding first the end portions of the shaft part are ground. The areas of larger diameter of the grinding wheel and the regulating wheel in this case have such a diameter that in fact first the end portions are ground on the shaft portion before the grinding wheel and the regulating wheel in the region of the largest rounding of the shaft part engages with this. As a result of this production of the polished sections on the end regions of the shaft part through the regions of larger diameter of the grinding wheel and the regulating wheel, the polished sections are produced concentrically with the axial centering of the shaft part and serve as a basis for the subsequent dimensional and shape-based grinding. This achieves an improved grinding result on the workpiece.

According to a second embodiment, however, it is also possible that the shaft portion used in centerless grinding according to the invention each have an area of increased diameter, preferably in the form of a collar in its end regions, which also first to the ground portions of the shaft portion with improved concentricity to the axial centerings are produced. However, this is only achieved if the region of increased diameter has a diameter such that initially the engagement of the grinding wheel and the regulating wheel takes place only on the polished sections on the end regions of the shaft part, without grinding already in the region of the greatest rounding error of the shaft part. This means that the grinding wheel and the regulating wheel in their areas corresponding to the intermediate areas of the shaft part have such diameters that the end areas of the shaft part are first ground.

In order to further improve the accuracy or concentricity of the shaft part after grinding, it is provided in shaft parts with a certain greater length according to a further embodiment that the grinding wheel and the regulating wheel are located in the intermediate region lying between the end regions of the shaft part, in particular in the middle, have a region of larger diameter, by means of which in addition to the polished sections at the end regions, a likewise concentric to the centering support seat is ground to the shaft part. Preferably, this supporting seat to be ground is arranged in the region of the maximum rounding error of the shaft part. This support seat is preferably ground by the fact that the grinding wheel and the regulating wheel each have an area of increased diameter in this area. Analogous to the grinding of the end regions of the shaft part and the correspondingly formed profiled side regions of the grinding wheel and the regulating wheel or the enlarged diameter in the end regions of the shaft part, according to a development, the shaft part itself preferably has in its central region or intermediate region a region of increased diameter, which initially either coincides with the grinding of the end regions or after this comes into contact with the grinding wheel and the regulating wheel.

Preferably, it is also possible that, depending on the length of the shaft part to be ground still another concentric support seat or even more concentric support seats are sanded.

According to the method of the invention, the end portions of the shaft portion and then either the support seat or the support seats are sanded in the presence of a support seat on the shaft part and then ground the shaft part in its entire length, or the end portions and the support seat or the support seats are sanded simultaneously.

The dimensioning of the distance, d. H. the profiling of grinding and regulating wheel or the dimensions of the shaft part, either at the end portions of the shaft part or in the central region is designed so that this distance is so small that initially a grinding at the end and only then a grinding in the area the largest concentricity of the shaft part takes place, which is preferably possible even in the presence of a arranged between the end regions support seat.

According to one embodiment of the invention, the grinding wheel and the regulating wheel in the intermediate region, which lies between the end regions of the shaft part to be ground, are profiled to a small extent. This low profiling includes such a number of respective grooves in both the grinding wheel and the regulating wheel as seats on components, in particular cams, are needed on the finished shaft part. Such cam seats do not constitute support seats in the sense of the present invention and only have a small increase in diameter of, for example, approximately 0.02-0.05 mm relative to the remaining area of the camshaft part. However, such a cam seats for fastening of respective cams exhibiting shaft part is otherwise centerless also ground according to the method of the invention, so that compared to the ground with known Centerless loops shaft part has an increased, ie improved concentricity to the axial centerings. This higher accuracy of concentricity of the camshaft body leads to improved running and operating conditions of the finished assembled camshaft in the respective engines.

Fig. 1

eine prinzipielle Anordnung von Schleifscheibe und Regelscheibe mit einem einen Rundschlagfehler aufweisenden Wellenteil, welches in seinen Endbereichen durch entsprechend an den Seiten profilierte Schleifscheiben und Regelscheiben zuerst angeschliffen wird;

Fig. 2

eine Anordnung wie in Fig. 1, jedoch mit einer zusätzlichen Profilierung im Zwischenbereich zwischen den Endbereichen zur Erzeugung eines für einen Stützsitz dienenden weiteren Anschliffes, welcher im Bereich des größten Rundschlages noch nicht in Kontakt mit dem Wellenteil gelangt ist;

Fig. 3

eine Anordnung gemäß Fig. 2, bei welcher im Bereich des größten Rundschlagfehlers des Wellenteils der Kontakt zur Schleifscheibe gerade eingetreten ist;

Fig. 4

ein Ausführungsbeispiel, bei welchem Schleifscheibe und Regelscheibe einen im Wesentlichen konstanten Durchmesser aufweisen, das Wellenteil jedoch an seinen Endbereichen jeweils einen Bereich vergrößerten Durchmesser aufweist, welcher für einen erfindungsgemäßen Anschliff vorgesehen ist;

Fig. 5

ein Ausführungsbeispiel gemäß Fig. 4, bei welchem mittels Schleifscheibe und Regelscheibe im jeweiligen Endbereich des Wellenteils bei dort vorhandenem, größerem Durchmesser des Wellenteils der Anschliff erfolgt, wobei zusätzlich im Bereich des größten Rundschlagfehlers ein Bereich vergrößerten Durchmessers am Werkstück vorhanden ist, welcher für die Erzeugung eines Anschliffes für einen Stützsitz vorgesehen ist;

Fig. 6

die Ausgestaltung gemäß Fig. 5, wobei jedoch der für den Stützsitz vorgesehene Bereich vergrößerten Durchmessers am Werkstück gerade ebenfalls angeschliffen wird; und

Fig.7

in axialer Richtung der Schleifscheibe und der Regelscheibe die prinzipielle Anordnung des Schleifspaltes mit der Darstellung des Abstandes zwischen der Schleifscheibe und der Regelscheibe im Schleifspalt beim untermittigen Schleifen und Abstützung durch ein Auflagelineal.

Further advantages and specific details of specific embodiments of the method according to the invention and of the grinding wheel and regulating wheel pair according to the invention will now be described with reference to the following drawings. In the drawings show:

Fig. 1

a basic arrangement of grinding wheel and regulating wheel with a round impact error having shaft portion which is first ground in its end by corresponding profiled on the sides grinding wheels and regulating wheels;

Fig. 2

an arrangement as in Fig. 1 , but with an additional profiling in the intermediate region between the end regions for generating a further bevel serving for a support seat, which has not yet come into contact with the shaft part in the region of the largest round impact;

Fig. 3

an arrangement according to Fig. 2 in which contact with the grinding wheel has just occurred in the region of the greatest rounding error of the shaft part;

Fig. 4

an embodiment in which the grinding wheel and regulating wheel have a substantially constant diameter, the shaft part, however, at its end regions in each case an area enlarged diameter, which is provided for a bevel according to the invention;

Fig. 5

an embodiment according to Fig. 4 in which by means of grinding wheel and regulating wheel in the respective end region of the shaft part there existing, larger diameter of the shaft part, the polished section, wherein additionally in the region of the largest rounding error, a region of increased diameter on the workpiece is provided, which provided for the production of a bevel for a supporting seat is;

Fig. 6

the embodiment according to Fig. 5 wherein, however, the area provided for the support seat enlarged diameter of the workpiece is also just sanded; and

Figure 7

in the axial direction of the grinding wheel and the regulating wheel, the basic arrangement of the grinding gap with the representation of the distance between the grinding wheel and the regulating wheel in the grinding gap at the bottom grinding and support by a support ruler.

The Fig. 1 to 6 show a basic arrangement in plan view in an arrangement of the workpiece between the grinding wheel 1 and the regulating wheel 2 in a sectional course through the cutting planes 27 according to Fig. 7 ,

In Fig. 1 is disposed between the grinding wheel 1 and the regulating wheel 2, a shaft part 9, which has a curvature in exaggerated representation, so that in the central region of a maximum rounding error is present. Both the grinding wheel 1 and the regulating wheel 2 have at their lateral end portions profilings 3 and 4, which areas of larger diameter 5 of the grinding wheel 1 and larger diameter 6 of the regulating wheel 2 have. The diameters of the regions of increased diameter 5, 6 are dimensioned such that they are ground with them at the end regions of the shaft part 9, to which at the respective end faces centering 11 are introduced, before the grinding wheel 1 and the regulating wheel 2 in the region largest round impact of the shaft part 9 come into contact with this. Due to the profiling 3, 4 of the grinding wheel 1 and the regulating wheel 2, the distance between the grinding wheel 1 and the regulating wheel 2 in the region in which the respective end portions of the shaft part 9 are ground, less than the distance 8 of the lying between the end portions 28 Intermediate area 29. In these profiles 3, 4 of the grinding wheel 1 and the regulating wheel 2 in - based on the state of grinding - end portion 28 of the shaft portion 9, a first defined grinding takes place at both end portions 28 of the shaft portion, whereby a high degree of concentricity of the end portions 28 of the shaft part 9 with respect. The introduced at the end portions 28 centerings 11 is achieved.

As well in Fig. 1 as well as in the Fig. 2 to 6 a shaft part 9 to be ground is shown, which additionally has a collar, which is also used in this centerless grinding method is grinded from the outer diameter. For this purpose, a corresponding groove is provided in the grinding wheel 1 and also in the regulating wheel 2. The profiled areas 3, 4 of the grinding wheel 1 and the regulating wheel 2 according to the Fig. 2 to 6 are identical in dimensioning to the embodiment according to FIG Fig. 1 , In addition to the embodiment according to Fig. 1 points to Fig. 2 the grinding wheel 1 and the regulating wheel 2 approximately in the region of the maximum rounding error of the shaft part to be ground, an additional profiling 30, which is a distance 13 for a support seat 15 to be ground (s. Fig. 3 ) trains. In the illustration according to Fig. 2 the distance 13 for the support seat is such that nevertheless first the end regions 28 of the shaft part 9 are ground by the profilings 3, 4 of the grinding wheel 1 and the regulating wheel 2, before the supporting seat 15 is ground by means of the profilings existing in the region of the greatest rounding error ,

In Fig. 3 is the embodiment according to Fig. 2 shown, but the profiling 30 in the region of the largest round impact error of the shaft part on the grinding wheel 1 and the regulating wheel 2 have just come into engagement and the end portions 28 are at least partially ground on the shaft part 9 already.

Fig. 4 shows a further embodiment according to the invention, in which the grinding wheel 1 and the regulating wheel 2 with respect to the dimensional and shape retention of the shaft part 9 have substantial areas of constant diameter. Both the grinding wheel 1 and the regulating wheel 2 thus have, except for the collar 12 on the shaft part 9 no profiling in their edge regions. Rather, the shaft part 9 is formed so that it has at its end regions in each case a collar, ie areas of larger diameter. According to Fig. 4 the workpiece 9 is also shown in an exaggerated manner with a curvature having a maximum rounding error approximately in its center. The grinding wheel 1 and the regulating wheel 2 are in the in Fig. 4 However, it is apparent that the intervention is imminent. According to the invention, the engagement initially takes place at the region of the collar, ie at the end regions of the shaft part 9, because there the distance between the grinding wheel 1 and the regulating wheel 2 is less than in the intermediate region, even in the region of the greatest rounding error of the shaft part 9.

In Fig. 5 a further embodiment is shown, in which by the region of increased diameter, ie the collar 14 in the end region of the workpiece 9, a polished section, wherein as a situation just the engagement of grinding wheel 1 and regulating wheel 2 is shown. In the area of the largest rounding error of the shaft part 9, an area of increased diameter 31 on the shaft part "ie a further collar is provided, which is suitable for grinding an additional support seat is provided. Such an additional support seat is useful above all when certain larger lengths of the workpiece, ie the shaft part are present. In the situation according to Fig. 5 however, the area intended for the support seat is not ground yet. Only when a sufficiently strong bevel has taken place in the end regions of the shaft part 9, the grinding wheel 1 and the regulating wheel 2 will come into engagement with the central collar on the workpiece for grinding a support seat.

This situation is in Fig. 6 shown, which in their details but otherwise the representation according to Fig. 5 equivalent.

In simplified representation is in Fig. 7 in side view, ie in a view in the direction of the longitudinal axes of the grinding wheel 1 and the regulating wheel 2, the arrangement of the distance between the grinding wheel and the regulating wheel including the arrangement of the shaft part 9 at this distance, that is shown in the grinding gap in conjunction with the support ruler 16. The wave-shaped part or the shaft part 9 is moved by engagement of the grinding wheel 1, which is driven in the direction of rotation 21, about its longitudinal axis 19 when resting on the support surface 24 of the support ruler 16 in the direction of rotation 23. Opposite the regulating wheel 2 is in its rotational direction 22 also in engagement with the shaft part 9 and thereby supports its rotation and forms together with the support surface 24 of the support ruler an abutment for introducing the grinding forces of the grinding wheel 1. The grinding wheel 1 rotates about its axis of rotation 17 and the regulating wheel 2 about its axis of rotation 18. Depending on the current diameter of the workpiece, the grinding wheel 1 is delivered in the feed direction 25, wherein the feed direction of the regulating wheel is characterized by the double arrow 26. Under delivery direction in each case a positive or negative feed direction is characterized, which is represented by the respective double arrows 25 and 26 respectively. The reference numeral 27, the cutting plane through the grinding wheel 1 and the regulating wheel 2 is shown, so that in the Fig. 1 to 6 shown distance refers to the related to the cutting planes 27 distance.

With the method according to the invention it is possible to produce a higher concentricity of a wave-shaped part relative to the axial centerings present at the end regions. The method prevents according to the invention that the rounding error which generally always exists in the case of shaft parts has a negative effect on the concentricity or concentricity of the finished component.

Bezuaszeichenliste:

1

grinding wheel

2

Regulating wheel

3

Profiling the grinding wheel

4

Profiling the regulating wheel

5

Area of larger diameter of the grinding wheel

6

Area of larger diameter of the regulating wheel

7

Distance between grinding wheel and regulating wheel in the end area of the shaft part

8th

Distance between grinding wheel and regulating wheel in the intermediate area of the shaft part

9

Shaft part / workpiece

10

Longitudinal axis / workpiece

11

Centering in the end of the shaft part

12

Covenant on the shaft part

13

Distance between grinding wheel and regulating wheel for support seat

14

Collar in the end of the shaft part

15

Support seat on the shaft part

16

edition ruler

17

Rotary axis grinding wheel

18

Rotary axis regulating wheel

19

Rotary shaft shaft part

21

Direction of rotation grinding wheel

22

Direction of rotation regulating wheel

23

Direction of rotation shaft part

24

Support surface on support ruler

25

Infeed direction grinding wheel

26

Feed direction regulating wheel

27

cutting plane

28

end

29

intermediate area

30

additional profiling on grinding and regulating wheel for support seat

31

Area of larger diameter on the shaft part for support seat

Claims (8)

1. Method for the centreless grinding of shaft parts (9), in particular of tubes for assembled camshafts, in which the shaft part (9) to be ground, having axial centring means (11) at its ends, driven in rotation at a distance (7, 8) between grinding wheel (1) and regulating wheel (2), is ground, the grinding wheel (1) and the regulating wheel (2) each having a width which corresponds at least to the length of the shaft part (9) and ground portions formed concentrically with the centring means (11) are firstly ground on the shaft part (9) in its end regions (28),
   which is followed by the grinding of the intermediate region (29) located between the end regions (28), followed by a dimension- and shape-maintaining grinding of the complete shaft part (9) to the final dimension on the basis of the ground portions made concentrically with the centring means (11), resting on a supporting straightedge (16) on the end regions (28) of the shaft part (9).
2. Method according to Claim 1, in which the shaft part (9) is ground in its end regions (28) by the grinding wheel (1) and regulating wheel (2) each having a larger diameter there, at a smaller distance (7) between the grinding wheel and the regulating wheel, which distance is formed as a result in the regions corresponding to the end regions of the shaft part.
3. Method according to Claim 1, in which the shaft part (9) has in its end regions (28) a respective region of larger diameter formed as a collar (14), and the grinding wheel (1) and the regulating wheel (2) have diameters in their regions corresponding to the intermediate regions (29) of the shaft part (9) such that the collar (14) of the shaft part (9) is ground first.
4. Method according to Claim 1 or 2, in which the grinding wheel (1) and the regulating wheel (2) each have a region of greater diameter (30) in the intermediate region (29) located between the end regions (28), in particular in the middle, by means of which at least one supporting seat (15) that is concentric with the centring means (11) is ground on the shaft part (9).
5. Method according to Claim 4, in which the end regions (28) of the shaft part (9) are ground first, then the at least one supporting seat (15) is ground and after that the shaft part (9) is ground over its entire length.
6. Method according to Claim 4, in which the end regions (28) and the at least one supporting seat (15) are ground simultaneously.
7. Method according to Claim 2, in which the smaller distance (7) provided in the end regions (28) of the shaft part (9) has a value such that grinding on a maximum run-out of the shaft part (9) present in the region between the end regions (28) is started at the earliest after the grinding of the end regions (28) of the shaft part (9) has been carried out.
8. Method according to one of Claims 3 to 7, in which the collar (14) present in the end regions (28) of the shaft part (9) has a diameter such that grinding on the maximum run-out of the shaft part (9) present in the intermediate region (29) between the end regions (28) is started at the earliest after the grinding of the end regions (28) of the shaft part (9) has been carried out.

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