EP1420913A2

EP1420913A2 - One-piece joint body

Info

Publication number: EP1420913A2
Application number: EP02779266A
Authority: EP
Inventors: Guido Degen; Wolfgang Schiemenz; Eberhard Ernst; Rainer Schmitt
Original assignee: GKN Sinter Metals Holding GmbH
Current assignee: GKN Sinter Metals Holding GmbH
Priority date: 2001-08-31
Filing date: 2002-08-17
Publication date: 2004-05-26
Also published as: JP2005501965A; KR20040029079A; JP4307256B2; MXPA04001689A; DE10142805A1; BR0212106A; DE10142805C2; CN1578709A; CN100444993C; AU2002342616A1; WO2003020460A2; US20040197219A1; WO2003020460A3

Abstract

The invention relates to a method for producing a metal component, in particular an internal joint part (3) of a Cardan joint (1), which is provided with ball paths (7). According to the invention: a charge cavity (28) is filled with powder; the charge cavity (28) is delimited by means of a die (27), at least one moulding mandrel (22) and a charging mandrel (23) positioned opposite the latter, a central mandrel (26) and at least one lower and upper punch (24, 25); the powder is compressed in the charge cavity (28) by pressure on the upper and/or lower punch to form a green product, which is then expelled and sintered.

Description

One-piece joint body

description

The invention relates to a metallic sintered part, in particular an inner joint part of a shaft joint, with ball tracks arranged at an angle to the pressing direction and / or a curvature of the ball tracks, together with a method and device for carrying it out.

Universal joints consisting of an inner joint part and an outer joint part are known. They are primarily used for torque transmission between shafts that are subject to major displacements during operation. The absorption of axial displacements is also possible.

An example of the transmission of torque via mutually angled shafts is the constant velocity universal joint. Constant velocity universal joints belong to the genus of the journal joints, the most common design of which is the universal joint. In the universal joint, the joint forks of the two shafts are connected with a pin. Simple universal joints allow essentially small changes in angle. Axial and radial displacements of the shafts are not possible.

The constant velocity joint avoids these disadvantages. In contrast to the universal joints, constant speed shaft joints produce uniform speeds on the output side at a uniform angular velocity. The same applies to the torques.

The PTO shaft consists of two joints and an intermediate shaft. The intermediate shaft is usually designed as a telescopic shaft to compensate for changes in length. The condition for a uniform transmission is that the two articulated forks lie in one plane and, if the deflection angles on both articulated forks are always the same size, at least in the most frequently occurring position during operation. This can be done by Z- or W arrangement can be achieved. The former is usually common in motor vehicles. Non-uniformities only occur in the intermediate shaft. Double joints are used to compensate for large angular movements in a small space, for example in the front wheel drive of motor vehicles. These correspond in principle to the cardan shaft, but instead of the intermediate shaft there is only a short intermediate piece - shaft or sleeve - which is guided in such a way that the deflection angles of both joints are always the same. The longitudinal displaceability is provided in the input or output shaft. Enable next to it

Constant velocity joints ensure a uniform, non-positive transmission of the torque or the angular velocity mostly via balls which are guided in ball tracks so that they always lie in the mirror plane of the joint. Centering is required for larger constant velocity joints. The constant velocity joints enable uniform transmission with large deflection angles. Constant velocity joints are built as fixed joints or sliding joints, whereby the fixed joint fixes the drive axle in the axial direction and the sliding joint enables compensation for changes in the length of the axle by longitudinal displacement.

Universal joints of this type are connected to the shafts with an outer joint part and an inner joint part. The inner joint part is guided via balls in the outer joint part. The balls move in a ball cage in ball tracks which are formed on the outer surface of the inner joint part and on the inner surface of the outer joint part. The geometry of the shaft joints requires that the recesses for the ball tracks be machined.

This type of manufacturing usually requires costly and high-precision machining. The disadvantage here is that the inner joint part has to be produced in a large number of work steps and in different processing machines. So far, the inner joint part has been conventionally formed from a forged blank, since the undercuts or formations, for example the Ball tracks, could not be produced in any pressing process and thus could not be pressed from metal powder and sintered to the final shape. This usually required additional process steps to achieve the shaping of the undercuts.

The object of the invention is to provide a method and a device with which a metallic sintered part or forged part, in particular an inner joint part of a shaft joint, can be produced in a simple and precise manner.

The invention solves this problem with the features specified in the method, device and property claims.

According to the invention, a method is proposed for producing a metallic sintered part or forged part, in particular a joint inner part of a shaft joint having ball tracks, powder being filled into a filling space, the filling space being delimited by a die, at least one shaping mandrel and a filling mandrel arranged opposite it, a central mandrel, at least one lower and one upper stamp, the powder in the filling space being pressed, ejected and sintered into a green compact by the pressure between the upper and lower stamps. Metallic sinter powder is introduced into the filling space. The mandrel is retracted up to the filling mandrel and the part geometry is fixed by moving the tools relative to each other and then the powder becomes one by applying a pressure to the upper and / or lower punch

Green compacted. The finished green compact is ejected from the pressing device and sintered after the upper punch and the mandrels have been moved back. To achieve a higher density, it is expedient if the sintered part is post-shaped hot or cold after sintering. A calibration process after sintering and / or forging is possible to achieve low tolerances and / or partial compression. For example, it is advantageous to Roll the inner part of the joint cold or alternatively roll after sinter forging.

Components produced by sinter metallurgy have the advantage that the entire body of the inner joint part forms a high-strength structure which has excellent material properties and surface quality.

In an advantageous embodiment of the invention it is provided that for the filling process the mandrel moves into a filling position in the die, the central mandrel moves into a filling position in the die and the lower punch is held in a filling position, during the pressing process the mandrel assigned to the mandrel moves into the Die, with the mandrel pushing the mandrel downwards in the die and thereby the ball tracks are formed in the powder due to the geometry of the mandrel, and at the same time the upper punch is inserted into the die up to an upper punch press position and the powder is compacted into the green compact, whereby ball tracks through the Geometry of the die are formed, and the lower punch moves in to a lower punch end position and the powder is also compacted, the upper punch and mandrel extend during the ejection process and the central mandrel is withdrawn from the green compact. The outer contour of the inner part of the joint, the ball hub, is partly formed by the die itself and partly by mandrels that can move in the die in the pressing direction. Depending on the geometry of the inner joint part, at least two upper mandrels and two lower mandrels, preferably three mandrels, which are displaceably mounted in the die in the pressing direction, are provided.

In a particularly advantageous embodiment of the invention, it is provided that the side of the filling mandrel facing the shaping mandrel in the filling position is flush with the top of the die and the top of the central mandrel, in the pressing position the shaping mandrel rests against the top of the mandrel and this pushes back while at the same time pressing pressure is applied to the upper punch, which enters the die and then move the upper punch and the mandrel out of the die and the pressed green body is ejected from the die through the lower punch.

In an expedient embodiment of the invention it is provided that the powder is pressed into a green body by pressure and heat.

In a particularly expedient embodiment of the invention it is provided that the die and at least one punch are heated during the pressing.

In an expedient embodiment of the invention it is provided that the shape of the ball tracks is shaped by the mandrels.

In a further expedient embodiment of the invention it is provided that the shape of the ball tracks is shaped by the mandrels and the die.

In an advantageous embodiment of the invention it is provided that the surface of the ball tracks is compressed after sintering. The surface may be compacted to achieve greater strength, for example by roller burnishing, it being advantageous if only partial areas of the ball track surface are compacted. It is expedient if at least the running surface of the balls of the ball track surface is compressed.

In a particularly advantageous embodiment of the invention it is provided that the surface of the ball tracks is compressed after sintering by means of at least one ball which exerts pressure perpendicular to the ball track surface.

In a further advantageous embodiment of the invention it is provided that the ball compresses at least one partial area of the ball track at least once. It is useful if the ball, which is preferably made of hard metal, has little least once, preferably several times over the surface to be compacted, so that the surface is gradually compacted and deformed.

In an advantageous embodiment of the invention it is provided that the finished sintered part is then forged, the sintered part being inserted with ball tracks into the die on a central mandrel, a forging tool for shaping the outer contour pressing the sintered part, and this is then ejected.

In a further advantageous embodiment of the invention, it is provided that the finished sintered part is calibrated after sintering or forging, the sintered part being inserted into the die on a central mandrel with ball tracks, a calibration tool for shaping the outer contour pressing the sintered part, and this is then expelled.

A further solution to the problem is given by a device for producing metallic sintered parts, in particular an inner joint part of a shaft joint, with ball tracks, with a pressing device, with at least one shaping mandrel and at least one filling mandrel assigned to the shaping mandrel, a lower and an upper punch and one Middle mandrel, which form the filling space and are radially enclosed by a die. Such a pressing device is characterized by a simple workflow. The pressing process is inexpensive and, above all, time-saving in comparison to the known machining production. This makes it possible to produce a large number of inner joint parts in a short time. The die, which surrounds the filling and forming mandrels, absorbs the pressing pressure acting radially on the forming mandrels.

In an advantageous embodiment of the invention it is provided that three mandrels and three mandrels assigned to them are provided, which are guided in recesses in the die. The arranged in the recesses of the die Neten filling and forming mandrels and the die itself form the outer contour of the inner joint part that, due to its geometric design, cannot be produced with conventional pressing devices.

The object is further achieved by a metallic sintered part, in particular the inner joint part of a shaft joint, with ball tracks arranged on the outer circumference, the sintered part being formed in one piece. For reasons of the strength and the service life of the inner joint part, it is advantageous to form it in one piece and not to assemble it from, for example, two components that are easy to manufacture by pressing technology.

In an expedient embodiment of the invention it is provided that the ball tracks are arranged at an angle to the press axis and / or are curved to the press axis. The inner joint part is designed with undercuts, recesses and profiles, preferably with the axis of the joint body, i.e. also to the pressing direction, axially aligned on the outer surface, radially curved ball tracks, the ball tracks are designed with a track base and track sides and the inner joint part has a geometry that enables the inner joint part to be pressed axially and removed from the pressing device or forging device.

In a further expedient embodiment of the invention it is provided that the ball tracks are round.

In an advantageous embodiment of the invention it is provided that the ball tracks are approximately elliptical. This configuration is particularly advantageous since the balls only rest on the ball track at two points and when rolling only one contact line results on the ball track. As stated above, this area is advantageously compacted and, if appropriate, heat and / or surface treated. In an advantageous embodiment of the invention it is provided that the ball tracks are polygonal. This configuration of the ball track, like the approximately elliptical ball track, has the advantage that the balls have only a small contact surface on the ball track and thus the rolling resistance drops and in particular the Hertzian pressure can be optimized.

In an advantageous embodiment of the invention it is provided that the ball tracks have a higher density in partial areas, in particular in the area of the ball contact surface.

In a further advantageous embodiment of the invention, it is provided that the ball tracks are heat-treated in partial areas, in particular in the area of the ball contact surface. Such a component has the advantage that the ball tracks receive high strength. The component can be heat-treated at least in the area of the ball tracks, for example by induction hardening and case hardening.

In a particularly advantageous embodiment of the invention, it is provided that the ball tracks are surface-treated in partial areas, in particular in the area of the ball running surface. For example, the surface can be treated by shot peening, plasma nitriding, nitrocarburizing, phosphating and rolling in a cold and warm condition in order to optimize the properties of the ball contact surface.

In the drawings, the invention is illustrated using an embodiment of a constant velocity universal joint. Show it:

1 a constant velocity universal joint,

Fig. 2 is a perspective view of a

Pressing tool for a ball hub, 3 shows the pressing tool cut with the mandrels retracted,

4 the pressing tool in the filling position,

5 the pressing tool in the pressing position,

6 the pressing tool in the ejection position,

Fig. 7 is a ball hub in plan view

8 shows a ball hub according to section A-A in FIG. 7

Fig. 9 is a ball track with ball in cross section

1 shows a constant velocity universal joint 1. It has an outer joint part 2 and an inner joint part 3. The outer joint part 2 is connected to a shaft 4, and the inner joint part 3 is connected to a shaft 5. The

Shaft 4 and shaft 5 form a drive-output system. The inner joint part 3 is received in the outer joint part 2. Balls 6 are arranged in ball tracks 7 between the outer joint part 2 and the inner joint part 3 such that the balls 6 are guided against each other in the ball tracks 7 when the shafts 4, 5 are bent. The balls inevitably run in the mirror plane. In the form shown, the bending angle is 0 ° and the ball lies in a plane perpendicular to the straight line formed by the axes of the shafts 4 and 5. The arrangement has a cover ring 8 which holds the ball in the ball tracks. When the drive shaft is rotated, the output shaft is transmitted at a constant speed and torque even with appropriate deflection within the possible limits. The shaft joint 1 is sealed to the outside with a flexible seal 18.

The ball tracks 7 can be arranged parallel or at an angle to the press axis (ball hub axis 20). Farther it is possible that the ball tracks 7 are curved to the press axis (ball hub axis 20). Radially curved ball tracks 7 are thus possible, the ball tracks 7 being designed with a track base 12 and track sides 13.

2 shows a perspective view of a pressing device 21 for a ball hub 3 (inner joint part), the pressing device 21 having three shaping mandrels 22.1, 22.2, 22.3 and filling mandrels 23.1, 23.2, 23.3 assigned to them. A lower punch 24, an upper punch 25 and a central mandrel 26 are also provided. The punches 24, 25 and mandrels 22, 23, 26 are radially enclosed by a die 27. The die 27, which surrounds the filling and shaping mandrels 23, 22 intercepts the pressing pressure acting radially on the shaping mandrels 22.

The shaping mandrels 22 and the filling mandrels 23 assigned to them are guided in recesses 28.1, 28.2 in the die 27. The filling and shaping mandrels 23, 22 arranged in the recesses 28.1, 28.2 of the die 27 and the die 27 itself form the outer contour of the inner joint part 3, which, due to its geometric design, cannot be produced with conventional pressing devices.

FIG. 3 shows a perspective view of the pressing device 21, the shaping mandrels 22 being inserted into the die 27. During the pressing process, the mandrels 22 move into the die 27, the mandrels 22 pushing the mandrels 23 down in the die 27, the ball tracks 7 of the ball hub 3 being formed in powder by means of the geometry of the mandrel 22.

Fig. 4 shows the pressing tool 21 in the filling position. It is provided that for the filling process the filling mandrel 23 moves into a filling position in the die 27, the center mandrel 26 moves into a filling position in the die and the lower punch 24 is held in a filling position. In the filling position, metallic sintered powder 29 is filled into the filling space 28, the filling space 28 being delimited by the die 27, the three mandrels 22.1, 22.2, 22.3 and the mandrels 23.1, 23.2, 23.3, the central mandrel 26, and the lower and upper punches 24, 25 arranged opposite them. In the filling position, the side of the mandrel 23 facing the mandrel 22 is at the same level as the top 30 of the die 27 and the top 31 of the central mandrel 26.

The filling and shaping mandrels 23, 22 arranged in the recesses 28 of the die 27 and the die 27 itself form the outer contour of the inner joint part 3 that, due to its geometrical design, cannot be produced with conventional pressing devices.

Fig. 5 shows the pressing tool 21 in the pressing position. The mandrels 22 are retracted up to the mandrels 23, the mandrels 22 pushing the mandrels 23 down in the die 27, and the ball tracks 7 of the ball hub 3 are formed in the powder by the geometry of the mandrels 22. At the same time, the upper punch 25 is moved into the die 27 up to an upper punch pressing position, so that the powder is compacted into the green compact, the ball tracks 7 also being shaped by the geometry of the die 27. The lower punch 24 moves up to a lower punch end position, whereby the powder is also compacted. The die 27, which surrounds the filling and shaping mandrels 23, 22 intercepts the pressing pressure acting radially on the shaping mandrels 22. By moving the tools relative to each other during the pressing process, the part geometry of the ball hub 3 is fixed.

It is advantageous if the sinter powder using

Heat is pressed into a green compact. For example, the die 27 and at least one punch 24, 25 can be heated during the pressing.

Fig. 6 shows the pressing tool 21 in the ejection position. At the

Ejection process, the upper punch 25 and the mandrel 22 are extended from the die 27. The central mandrel 26 is withdrawn from the green compact 3. The green compact 3 is ejected from the die through the lower stamp 24. The green compact 3 is then sintered.

It is advantageous if the completely pressed green compact 3 is post-shaped hot or cold to achieve a higher density after sintering. A calibration process after sintering and / or forging is possible to achieve low tolerances and / or partial compression. For example, it is advantageous to cold-roll the ball tracks 7 of the inner joint part 3 or alternatively to roll after sinter forging. It is advantageous if only partial areas of the ball track surface are compacted, at least the running surface 16 of the balls 32 of the ball track surface should be compacted.

The ball track surface can be compacted, for example, by compressing the surface of the ball tracks 7 after sintering by means of a ball which exerts pressure perpendicular to the ball track surface, the ball compressing at least a partial area of the ball track 7 at least once. However, it is advantageous if the ball, which is preferably made of hard metal, rolls several times over the surface to be compressed, so that the surface is gradually compressed and deformed.

It is advantageous if the finished sintered part 3 is subsequently forged, the sintered part 3 with ball tracks 7 being inserted into the die 27 on a central mandrel 26, a forging tool for shaping the outer contour pressing the sintered part 3, and this being subsequently ejected.

After sintering or forging, it is also advantageous if the sintered part 3 is calibrated. Tools can be used for the forging and calibration which have approximately the same design as the pressing tool 21 described above. In particular, it is also possible to forge a regular blank to form a ball hub 3 using the aforementioned forging tool.

Fig. 7 shows a ball hub 3 in a plan view. The ball hub 3 is formed in one piece, whereby the strength and the service life of the ball hub 3 is high. The ball tracks 7 are arranged at an angle to the press axis (ball hub axis 20). The ball hub 3 each has paired ball tracks 7. The ball tracks 7 are aligned axially into the image plane and have a radial curvature 14. The curvature 14 is opposed to each of the pair of ball tracks 7 assigned to one another, i. H. the ball tracks 7 run towards one another in an axial direction. The ball hub axis 20 runs perpendicular to the image plane through the center of the ball hub 3.

FIG. 8 shows a ball hub 3 according to section A-A in FIG. 7.

Fig. 9 shows a ball track 7 with a ball 32 in section. The ball 32 has a round geometry. The ball track 7 has a geometry that is approximately elliptical. The ball 32 runs on the running surface 16, 16 'and has two points of contact 17, 17' on the ball track 7 at each moment. Each point of contact 17, 17 'lies on a different track side 13, 13'. The points of contact 17, 17 'are separated at an angle 2δ from the center of the sphere. This configuration is particularly advantageous since the balls 32 rest only on the ball track 7 at two points and, when rolling, there is only one contact line on the ball track 7. The fact that the balls 32 have only a small contact surface on the ball track 7 reduces the rolling resistance. The curvature of the ball 32 and the ball track 7 are optimized so that the Hertzian pressure is minimized. This area is advantageously compacted and, if necessary, heat and / or surface treated. Processes would include induction hardening, case hardening, shot peening, plasma nitriding, Ni trocarburizing, phosphating and rolling in cold and warm condition

Claims

claims

1. A process for producing a metallic sintered part, in particular a joint inner part (3) of a shaft joint (1), which has ball tracks (7), powder being in a

Filling space (28) is filled, the filling space (28) is delimited by a die (27), at least one shaping mandrel (22) and a filling mandrel (23) arranged opposite this, a central mandrel (26), at least one lower and one upper punch (24, 25), the powder in the filling space (28) being pressed, pressed out and sintered into a green body by pressure on the upper and / or lower punch (24, 25).

2. The method according to claim 1, characterized in that for the filling of the mandrel (23) in a filling position in the

The die (27) moves in and the lower punch (24) is held in a filling position, during the pressing process the mandrel (22) assigned to the mandrel (23) moves into the die 27, the mandrel 22 the mandrel (23) in the die ( 27) pushes downwards and thereby through the geometry of the

Shaped mandrel (22), the ball tracks (7) are formed in the powder, and at the same time the upper punch (25) is inserted into the die (27) up to an upper punch pressing position and the powder is compacted into the green body, whereby ball tracks (7) are driven by the geometry the die (27) are formed, and the lower punch

(24) retracts to a lower punch end position and also compresses the powder, the upper punch during the ejection process

(25) and mandrel (22) extend from the die (27) and the central mandrel (26) is withdrawn from the green compact (3).

3. The method according to claim 1 or 2, characterized in that the mandrel (22) facing side of the mandrel (23) in the filling position flush with the top (30) of the die (27) and the top (31) of the central mandrel ( 26) completes, in the pressing position the mandrel (22) rests against the top (33) of the filling mandrel (23) and pushes it back, while at the same time pressing pressure is applied to the upper punch (25) and then the upper punch (25) and the shaping mandrel (22) extend out of the die (27) and the completely pressed green compact (3) is ejected from the die (27) through the lower punch (24).

4. The method according to any one of claims 1 to 3, characterized in that the powder is pressed by pressure and heat to form a green compact.

5. The method according to claim 1 or 4, characterized in that the die and at least one punch (24, 25) is heated during the pressing.

6. The method according to any one of claims 1 to 5, characterized in that the shape of the ball tracks (7) is formed by the mandrels (22).

7. The method according to claim 1 or 6, characterized in that the shape of the ball tracks (7) is formed by the mandrels (22) and the die (27).

8. The method according to any one of claims 1 to 7, characterized in that the surface of the ball tracks (7) is compressed after sintering.

9. The method according to any one of claims 1 to 8, characterized in that the surface of the ball tracks (7) after sintering by means of at least one ball (32) is compressed, the pressure perpendicular to the ball surface area, the compression in cold or warm Condition can take place.

10. The method according to any one of claims 1 to 9, characterized in that the ball (32) compresses at least once at least a portion of the ball track (7).

11. The method according to any one of claims 1 to 10, characterized in that the finished sintered part (3) is then forged, the sintered part (3) with ball tracks (7) in the die (27) placed on a central mandrel (26) is, a forging tool of the same type for shaping the outer contour presses the sintered part (3), and this is then ejected.

12. The method according to any one of claims 1 to 11, characterized in that the finished sintered part (3) is calibrated after sintering or forging, the sintered part (3) with ball tracks (7) in the die (27) on a central mandrel (26) is inserted, a calibration tool of the same design presses the sintered part (3) to shape the outer contour, and this is then ejected.

13. A method for producing a metallic component, in particular a joint inner part (3) of a shaft joint (1) having ball tracks (7), a blank being inserted into the die (27) on a central mandrel (26), a forging tool of the same type to shape the outer contour presses the blank, and this is then ejected.

14. Device for the production of metallic components, in particular sintered metallurgically manufactured and / or forged components, in particular an inner joint part of a shaft joint (1), with ball tracks (7), according to the method according to claims 1 to 13, characterized by a pressing device ( 21), with at least one shaping mandrel (22) and at least one filling mandrel (23) assigned to the shaping mandrel (22), a lower and an upper punch (24, 25) and a central mandrel (26), which form the filling space (28) and are radially enclosed by a die (27).

15. The device according to one of claims 1 to 14, characterized in that three mandrels (22) and three associated with this mandrel (23) are provided, which are guided in recesses (28) in the die (27).

16. Metallic component, in particular sintered metallurgically manufactured and / or forged component, in particular inner joint part (3) of a shaft joint (1), with ball tracks (7) arranged on the outer circumference, produced by the method according to method claims 1 to 13, characterized in that the sintered part is formed in one piece.

17. Metallic component, in particular sintered metallurgically manufactured and / or forged component, in particular

Inner joint part (3) of a shaft joint (1), according to one of claims 1 to 16, characterized in that the ball tracks (7) are arranged at an angle to the press axis (20) and / or are curved to the press axis (20).

18. Metallic component, in particular sintered metallurgically manufactured and / or forged component, in particular inner joint part of a shaft joint, according to one of claims 1 to 17, characterized in that the ball tracks are round.

19. Metallic component, in particular sinter-metallurgically manufactured and / or forged component, in particular inner joint part (3) of a shaft joint (1), according to one of claims 1 to 18, characterized in that the ball tracks (7) are approximately elliptical.

20. Metallic component, in particular sintered metallurgically manufactured and / or forged component, in particular inner joint part (3) of a shaft joint (1), according to one of the

Claims 1 to 19, characterized in that the ball tracks (7) are polygonal.

21. Metallic component, in particular sintered metallurgically manufactured and / or forged component, in particular

Inner joint part (3) of a shaft joint (1) according to one of claims 1 to 20, characterized in that the ball track nen (7) have a higher density in partial areas, in particular in the area of the ball tread (16, 16 ').

22. Metallic component, in particular sintered-metallurgically manufactured and / or forged component, in particular inner joint part (3) of a shaft joint (1), according to one of claims 1 to 21, characterized in that the ball tracks (7) in partial areas, in particular in the area of the ball contact surface (16, 16 ') are heat treated.

23. Metallic component, in particular sinter-metallurgically manufactured and / or forged component, in particular inner joint part (3) of a shaft joint (1), according to one of claims 1 to 22, characterized in that the ball tracks (7) in partial areas, in particular in the area the ball tread (16, 16 ') are surface treated.