DE112004001207B4 - Method for producing a joint with heavy-duty inner part - Google Patents

Abstract

Method for producing a joint (1) comprising at least one outer part (2), an inner part (3), a cage (4), a plurality of rolling elements (5) and a shaft (6), the shaft (6) and the Inner part (3) form a positive connection (7) and a maximum bending angle (8) in the range of at least 25 ° to an axis (9) of the joint (1) is adjustable, which comprises at least the following steps: a) providing an outer part ( 2), a cage (4) and a plurality of rolling elements (5); b) providing a shaft (6) which is executed in a connecting portion (15) with a spline (12); c) providing a blank (19) of directly hardenable steel for the inner part (3) with an opening (20); d) heat treatment of the inner part (3), wherein the inner part (3) with a hardness-free surface (10) in the region of the positive connection (7) is executed; e) providing the blank (19) with a spline (12) in the region of the opening (20) after step d); f) mounting the components.

Description

The invention relates to a method for producing a joint comprising at least an outer part, an inner part, a cage, a plurality of rolling bodies and a shaft. The shaft and the inner part together form a positive connection. The joint is designed to allow a maximum flex angle in the range of at least 25 ° to an axis of the joint. It is known that power transmission components such as torque transmitting constant velocity joints, drive shafts, cardan shafts, etc. are used for power transmission in the powertrain of motor vehicles in the rule. In the torque-transmitting connection of the individual components force and / or positive connections are often realized. Of particular interest in view of the present invention is the connection of a joint inner part with a shaft for torque transmission. The joint inner part, which is a ball hub in ball pivot joints and Tripodegelenken a Tripodestern is connected via a plug or spline, which is mounted in an inner bore of the inner joint part and at the end of the shaft part, torque-fixed to the shaft. This plug or spline has already proven itself in the automotive industry.

However, there has recently been a significant increase in the drive power and the drive torque of the motor vehicles. This means, for example, that a significantly higher static load for at least a part of the components of the joint, such as the cage occur.

First, it should be noted at this point that the load on the components of the joint is sometimes considerably dependent on the maximum achievable flexion angle of the joint and further increases with increasing flexion angle. Therefore, measures must be taken to ensure the function of the joint or ensure that in the event of a component failure, the vehicle remains manageable for the operator. This increased static load can also be detected with respect to the inner part, since with increasing flexion angle fewer rolling elements with the inner part in contact and thus the static forces that occur over an ever smaller number of point or linear contact areas of the rolling elements in the inner part be initiated. Now it should be ensured that the joint can withstand the increased requirements in automotive engineering permanently.

It should also be noted that recently, with regard to the components of the powertrain, the demand for small, compact and lightweight versions is noted. Thus, the existing space is to be fully exploited as far as possible, at the same time a reduction of the vehicle mass should lead to a reduced fuel consumption of the vehicle.

This plug or wedge connection requires a high accuracy of fit. With regard to the shape tolerances, it is usually necessary to classify the components to be joined together beforehand. The reason for this is, inter alia, that the known components, which are intended to enable a transmission of such torques even at large flexion angles, are case-hardened in the region of the connection to the contact surfaces. This case hardening, which is associated with the introduction of large amounts of heat over a long period of time leads to the corresponding parts to hardness distortions and deformations that may have to be at least partially reworked, in particular ground, must be.

The hardness distortions of the components which are present in the area of joints towards other components of the joint, such as, for example, in the area of the hub-shaft connection or the positive connection between the shaft and the inner part, prove to be particularly problematic. Especially at this coincidence very special requirements are made. When using such a joint in the automotive sector is z. B. technically a press fit required (eg., With a press-in force about 10,000 Newton), so that even under load of the joint no significant play with respect to this joint occurs. This interference fit is essentially limited by the component strength of the inner part.

• a) Klassifizieren Das Klassifizieren umfasst in der Regel ein Ausmessen der Geometrie der Keilverzahnung des Gelenkinnenteils bzw. der Welle. Anschließend werden die Komponenten einander zugeordnet, so dass sie laut Kundenanforderung gefügt werden können. Dieses Verfahren hat einen hohen logistischen Aufwand und einen hohen Platzbedarf zur Folge und ist zudem sehr arbeitsintensiv.
• b) Nachträgliche Hartbearbeitung des Innenteils Eine nachträgliche Hartbearbeitung erfolgt in der Regel an der im Bereich der Innenverzahnung des Innenteils bzw. der Nabe, wobei die Innenverzahnung durch Räumen im gehärteten Zustand des Innenteils an die Abmessungen der zu fügenden Welle angepasst wird. Dies führt zu sehr hohen Werkzeug bzw. Prozesskosten.
• c) Istmaß-Anpassung der Komponenten Hierbei wird zum Beispiel ein Rollverzahnungprozess der Welle (zur Herstellung einer Keilverzahnung der Welle) an die tatsächlichen Istmaße der Innenverzahnung des Innenteils angepasst. Dieses Verfahren erfordert jedoch eine zeitversetzte Fertigung, eine Lagerhaltung zumindest der einen Komponente und ist somit nur bedingt anwendbar.

Currently, there are three ways to counteract this problem of the exact fit of the components to be joined together (inner part, shaft):

• a) Classification The classification generally comprises a measurement of the geometry of the splines of the inner joint part or the shaft. Subsequently, the components are assigned to each other so that they can be added according to customer requirements. This method results in a high logistical effort and a high space requirement and is also very labor-intensive.
• b) Subsequent hard machining of the inner part A subsequent hard machining is usually carried out on the in the region of the internal toothing of the inner part or the hub, wherein the internal toothing is adapted by clearing in the hardened state of the inner part of the dimensions of the shaft to be joined. This leads to very high tool or process costs.
• c) actual dimension adjustment of the components Here, for example, a rolling toothing process of the shaft (for producing a Splines of the shaft) adapted to the actual actual dimensions of the internal toothing of the inner part. However, this method requires a time-staggered production, storage of at least one component and is therefore only conditionally applicable.

Out DE 31 32 363 C1 a method for partial surface hardening of an inner and outer joint body of a ball joint is known. Only part of the ball tracks and contact points with the cage are specifically hardened by an induction process.

On this basis, it is an object of the present invention to provide a method for producing a joint, which alleviates the known technical problems at least partially and meets the resulting requirements at least partially. In particular, a method is to be specified, by which a joint is generated, which ensures a permanent force or torque transmission even under high loads and maximum deflection. In this case, the joint should be produced with a particularly simple and inexpensive method, among other things, should also be made possible to produce sub-components of the joint locally separated from each other and to add without classifying each other.

These objects are achieved with a method for producing a joint with the steps according to claim 1. Further advantageous embodiments of the invention are described in the respective dependent claims. It should be noted at this point that the features listed individually in the claims can be combined with each other in any technologically meaningful manner and lead to further embodiments of the invention.

With the method according to the invention, a joint is produced that comprises at least an outer part, an inner part, a cage, a plurality of rolling elements and a shaft, wherein the shaft and the inner part form a positive connection and a maximum bending angle in the range of at least 25 ° an axis of the joint is adjustable, wherein the inner part comprises a directly hardenable steel.

By "joint" in particular constant velocity ball joints are meant. It is preferably one of the group: Rzeppa joint such. As UF, RF, AC joints or a so-called DO joint. UF stands for "undercut free", RF for "wheel-sided fixed joint" and AC for "angular contact". A major difference between the RF and AC joints is that the RF joint has a round and the AC joint an elliptical orbit. UF joints allow a greater maximum flexion angle due to a longer path than AC joints (up to over 50 °, compared to around 47 ° C for AC). A DO joint is a special sliding joint with tracks for the rolling elements that run parallel to the joint axis, whereby maximum deflection angles of up to approx. 31 ° can be achieved. In principle, it should be pointed out here that all projecting joints can be bent as desired within a range of 0 ° up to the maximum bending angle.

The functions of the individual components of the joint will now be explained in more detail using the example of a constant velocity ball pivot, in which case the rolling elements are designed as balls. In the outer part and the inner part, a plurality of longitudinally extending ball tracks are provided, with which the balls are guided for transmitting torque. For this purpose, the balls are guided simultaneously in radially opposed tracks in the inner part and in the outer part, wherein a cage is provided, which holds the balls in its cage windows each in a plane perpendicular to the axis.

Usually, the raceways are hardened on the outer part and / or on the inner part. The number of balls or rolling elements can be selected taking into account the available installation space and the requirements in terms of power transmission. In particular, constant velocity universal joints with 6, 8 or even 10 balls are common.

The joint now makes it possible to realize an angle and / or an axial offset (in the case of sliding joints) between the drive side and the driven side. The joints allow a maximum flexion angle in the range of at least 25 ° to the axis of the joint. The "bending angle" means in particular the angle between the axes, which is formed with the drive shaft or the output shaft or similar components. An aligned arrangement of drive shaft and output shaft thereby represents a deflection angle of 0 °. If the shaft is angled as far as possible, the "maximum deflection angle" is present. It can be seen from the above statements regarding the joints shown here that at least the UF, RC, AC and DO joints fulfill this condition, since they all have a maximum flexion angle above 25 °.

With such a large deflection of at least 25 °, in particular at angles above 30 ° or even 35 °, the static load of the inner part of the joint increases to a considerable extent. The reason for this is that not all existing rolling bodies are in contact with the inner part and Accordingly, the static forces is transmitted only over a reduced number of rolling elements on the inner part. This leads to a significantly increased, on fewer contact surfaces between the rolling element and inner part distributed force application. If, for example, an AC joint with 6 balls is considered, all balls are loaded evenly at a deflection angle of 0 °. From a deflection angle of about 15 °, the first ball pair is relieved, so that the force is increasingly shifted to the remaining 4 balls. At a flexion angle of about 25 °, the relief of the second pair of balls begins, that is, this ball pair now transmits a lower force than is the case with a flexion angle of 0 ° under the same load. From a bending angle of 30 °, the entire load is transferred to a high degree only by two balls, for example, they now transmit 2.5 times the load as with a bending angle of 0 °. The processes illustrated here for an AC joint with 6 balls can be shown in a comparable manner in other embodiments of the joints mentioned.

Here it has now been recognized that this behavior of the joints can lead to damage of the inner part at large deflections. Therefore, it is now proposed according to the invention, for joints that can be bent up to a maximum bending angles, the inner part with a directly curable steel. By "directly" curable is meant in particular that no carburizing of the steel is carried out in the course of a heat treatment, but the steel already has the composition (in particular a carbon content in the range of 0.2% to 0.8%), the hard by Microstructure transformation in at least partially martensitic structure allows. This creates conditions that allow a uniform structural structure of the inner part over the entire cross-section, thereby possibly boundary layers z. B. be avoided in terms of carbon content. With such a material on the one hand can be realized for the required life of the joint and the required breaking strength of the inner part, since hardening of the raceways for the rolling body can be achieved, and at the same time can be safely and permanently absorbed higher static forces at large bending angles, as the Force can be distributed evenly at the predominantly punctiform introduction points.

It is advantageous that the inner part comprises a tempering steel. The tempering steel has the property of being directly curable. This is largely attributable to its carbon content of 0.3% to 0.8%. After tempering, the tempering steel usually has a high toughness and a fine-grained structure. These toughening properties are particularly suitable for absorbing the forces occurring at large bending angles. The possible heat treatments will be explained later in detail, at this point is only to point out that under "tempering" here the direct hardening followed by tempering is understood, which may take place partially or for the entire inner part.

In contrast to the feed material, the required carbon content of a tempering material is contained in the material from the very beginning. This is tolerated and thus guarantees a certain training hardness, which is required for example to permanently manage the occurring Hertz surface pressures. This means that, depending on the contact of the force-transmitting components, different levels of stress concentration occur below the surface. For this, a hardness increase or an increase in strength of more than 3 times the basic hardness of steel is required (eg from 180 HV to 58 + 4 HRC). This increase in hardness is achieved by a microstructure in martensite. To avoid excessive component distortion and too low breaking strength, it is advisable to harden as precisely as possible (local, temporal, temperature-dependent, etc.). In the case of a component such as the inner part in question, which also has high notch factors (internal toothing, selective introduction of force via the rolling elements), the greatest possible residual toughness of the component is desirable. In addition, tests have proven that internal parts made of tempered steel generally have higher static fracture strengths than case hardened internal parts.

Preferably, it is now proposed that the inner part comprises a steel having a carbon content in the range of 0.4% to 0.6%. It has been found that especially such steels can permanently withstand a particularly high load at extreme bend angles. This applies in particular to the case that this is a tempered steel. Under certain circumstances, it may be advantageous to provide alloying components (such as manganese and / or boron) in the steel which result in an increase in hardenability or a further improvement in the toughness properties. Particularly preferred are, for example, steels with the German name Ck45, Cf53, C60.

According to a further embodiment of the joint, the inner part is designed with a hardness-free surface in the region of the positive connection. This means in particular that the inner part is present in this area in the tempered, ie tempered, state and thus there are no significant differences in hardness near the surface of the inner part. This is z. B. a nearly homogeneous ductility of the inner part, starting from this upper surface until well into the Cross-section into, possibly even over the entire cross-section realized, which is for example in the range of 500 HV to 600 HV. Such an embodiment of the inner part has the consequence that a simple and highly accurate production of the connection can be realized, at the same time the requirements for the power transmission is ensured. In addition, with the non- (use) hardened configuration of the internal toothing of the inner part, a kind of "good-natured predetermined breaking point" is provided, which may be used in the event of overstressing of the joint. The hardened shaft side of the positive connection would be safely guided in this case in the opening of the inner part. A non-hardening of the inner area for one allows, inter alia, the greatest possible elongation at break to cope with static requirements, a cheaper and easier production of the final geometry of the internal teeth (avoiding machining in the cured state) and a plastic deformability of the inner part-internal teeth during joining (possibly even with Avoid classification).

In addition, we now proposed that the positive connection is formed with a spline. By "spline" is meant, in particular, that the inner part or the shaft over the circumference a plurality of side by side alternately arranged feather keys and fitting grooves. The number of such circumferentially distributed keys or grooves is for example in the range of 15 to 40. The keys arranged on the peripheral surface of the spline usually have a modulus of about 1.05833. According to a preferred embodiment, the spline is performed with hardened feather keys of the shaft and hardness-free, tempered grooves / webs of the inner part.

According to a further embodiment of the joint, the inner part in a connecting portion with the positive connection has a hardness in the range of 55 HRC to 63 HRC, in particular in the range of 58 to 62 HRC. This now indicates a joint in which the region of the inner part is designed close to the positive connection with a hardened surface. Such joints can be burdened with particularly high static transmission torques. To avoid too low breaking strength, it is advantageous that the partial hardening is essentially limited to the loaded areas in order to obtain a relatively tough core of the inner part. In addition, it should be noted that a partial hardening in the area of the webs for the rolling bodies should be provided anyway.

It is also particularly advantageous if at least the outer part, the inner part and the cage comprise the same material. In such an embodiment of the joint is meant in particular one in which at least the cage and the inner part and preferably also the outer part or even additionally the rolling bodies are made with the same material. Preferably, this is a tempering steel, which is the basis for these components. This has in addition to the load technically significantly improved properties of the joint also other advantages, such as in terms of a more cost-effective procurement of materials due to the larger margin, easier storage and logistics and better recyclability of the joint result.

• a) Bereitstellen eines Außenteils, eines Käfigs und einer Mehrzahl von Rollkörpern;
• b) Bereitstellen einer Welle, die in einem Verbindungsabschnitt mit einer Keilverzahnung ausgeführt ist;
• c) Bereitstellen eines Rohlings aus direkt härtbarem Stahl für das Innenteil mit einer Öffnung;
• d) Wärmebehandlung des Innenteils, wobei das Innenteil mit einer härtefreien Oberfläche im Bereich der formschlüssigen Verbindung ausgeführt ist;
• e) Versehen des Rohlings mit einer Keilverzahnung im Bereich der Öffnung nach Schritt d);
• f) Montieren der Komponenten.

According to the invention, a method for producing a joint comprising at least an outer part, an inner part, a cage, a plurality of rolling bodies and a shaft is described. The shaft and the inner part finally form a positive connection and ensure the adjustability of a maximum flexion angle in the range of at least 25 ° to an axis of the joint. This method comprises at least the following steps:

• a) providing an outer part, a cage and a plurality of rolling elements;
• b) providing a shaft which is formed in a connecting portion with a spline;
• c) providing a blank made of directly hardenable steel for the inner part with an opening;
• d) heat treatment of the inner part, wherein the inner part is designed with a hardness-free surface in the region of the positive connection;
• e) providing the blank with a spline in the region of the opening after step d);
• f) mounting the components.

For the sake of clarity, it should be pointed out that the list mentioned above is not necessarily to be understood as a sequence of the different work steps or method steps. Thus, it is possible, for example, that steps a), b) and c), d), e) can be carried out at least partially simultaneously and under certain circumstances also spatially separated from one another. Of course, the assembly of other components of the joints can be integrated into the manufacturing process. The particular embodiment variants of the individual method steps will be discussed in more detail below.

The provision or production of an outer part, a cage and a plurality of rolling bodies can therefore be carried out independently and in a known manner. With regard to the provision of the shaft is to be noted that this is preferably a solid shaft of tempered steel or boron steel (particularly high hardenability and Einhärttiefen possible for high Transmission torques) is. The spline of the shaft can also be produced in a conventional manner and preferably independently of the production of the spline of the inner part. With regard to the provision of a blank made of directly hardenable steel for the inner part with an opening, it should be noted that this preferably comprises forging of the blank, wherein in particular the peripheral surface or the raceways for the rolling bodies are embossed. With regard to the properties of a directly hardenable steel, reference is made to the above (particularly preferred) embodiments. Finally, in this "soft" state of the blank, the spline is also incorporated in the region of the opening. In the event that a hardening (only) of the outer contour is made, the finishing of the spline of the inner part can be made even after the heat treatment in the "soft" state, in particular by means of the manufacturing process spaces, with distortions due to the non-existent heat input after the Rooms are avoided.

The heat treatment according to step d) comprises at least one curing process, which is to be understood here as heating and quenching to produce an at least partially martensitic microstructure in the blank. It can now be particularly benefited by the benefits of using a directly curable steel.

In principle, it should be pointed out that the hardening of the entire blank can be carried out (through hardening) or even only a partial, locally (in particular on areas near the surface of the inner part) limited hardening can take place (eg only the outer contour (running surfaces of the rolling elements ) and / or the area with the internal toothing). Curing may be required in case of an extremely high static requirement. Furthermore, an individual hardness structuring over the wall thickness is possible up to the tooth head, whereby a best possible compromise in terms of a required Zahnfußfestigkeit and cost manufacturability is possible. The preferred inductive firing allows almost any arbitrary hardness profile of the sharp partial outer contour hardening on structuring to curing. When hardening build up only very low internal stresses in the material. It should also be noted that this results in a hardened internal toothing, which provides a higher shearing resistance and a better freedom of play over the lifetime.

Here, a heat treatment is preferred which can be well integrated into the production line for producing such internal parts (by direct individual part curing), since the time periods required to provide a desired hardness of the inner part are much shorter than, for example, compared to case hardening. in which the material must first be enriched with carbon. According to the desired hardness properties of the inner part or the production (individually, batchwise or batchwise), the following hardening processes are proposed:

Heating methods:

• 1. Method for heating individual internal parts: a. by induction in the shot or feed process b. through an energy beam (eg laser, electron beam) c. by electrical resistance
• 2. Method for simultaneous heating of several internal parts in the run by means of an induction, electric or gas continuous furnace
• 3. A method for the simultaneous heating of several internal parts in a chamber by means of induction, electric, gas, or plasma chamber furnace.

Particularly preferred here is an inductive firing of the inner part integrated in the production line. It allows a very fast, highly efficient and targeted heating locally limited to the areas of the inner part, which are to be cured.

quenching:

• 1. Method for quenching individual internal parts: a. by quenching showers i. wrapping on the item or in the axial feed ii. axially on the single part or in the horizontal feed iii. on the side of the item or in the horizontal feed b. in the bath or whirlpool (mostly in free fall)
• 2. Process for deterring the internal parts in the batch: a. by axial immersion in an oil or salt bath b. through showers c. by gas quenching.

Particularly preferred in this case is a built-in hardening machine single-part ring shower quenching. This can be achieved noteworthy advantages. So a particularly environmentally friendly curing is possible, since a water-based quenching agent can be used, so that no special disposal is required. Furthermore, this quenching method is particularly low distortion, since it cools all around and at the same time. This allows an efficient, focused on an individual part, and economic heat treatment.

In this case, the method is preferably carried out so that the blank is coated during step d). During tempering, the tempering process is followed by a heat treatment, namely annealing. The hardening preferably takes place in a plant or machine (eg with cycle times of 10 to 30 seconds), so that the inner part does not have to be removed from the production line. Just in this case, therefore, a short-term reason (compared to the conventional furnace occasion) of the material of the inner part is preferred. Hereinafter, particularly advantageous variations of annealing will be described, which can be combined with the above-mentioned heating and quenching processes:

Starting procedures:

• 1. Method for starter heating of individual internal parts: a. by induction in the shooting process (tempering in seconds, eg 20-60 seconds) b. by electrical resistance c. in a warm bath (preferably oil or salt bath)
• 2. Method for simultaneous starter heating of several internal parts in the run by means of induction, electric or gas continuous furnace
• 3. A method for simultaneous starter heating of several internal parts in a chamber by means of induction, electric, gas, or plasma chamber furnace
• 4. Procedure for Warming the Warm in the Warm Bath (preferably Oil or Salt Bath)

In this case, the method for starter heating in the induction continuous furnace is preferred, since this method can be incorporated particularly well into the production line of mass production of internal parts. The cycle time for this is z. B. 10 to 30 seconds, with only a small footprint and at the same time a high versatility is feasible. This method allows a fairly rapid heating of the inner part (eg, compared to a gas oven), whereby a total annealing time of an inner part z. B. is present in the range of 3 to 15 minutes. The tempering temperatures are preferably in the range of 160 ° to 190 ° C. This can ultimately be a production of tempered internal parts with a cycle time as a modern mass production line (about 10-30 seconds) can be realized.

Advantageous with respect to a partial hardening or tempering of the inner part in the region of the outer contour (with the rolling surfaces for the rolling elements) and the opening (near the positive connection) is that the hardened inner toothing allows the transmission of higher maximum torques. At the same time, production-integrated hardening with lower distortion is possible. The inner part thus produced has a significantly improved breaking strength compared with case-hardened inner parts, as they were previously used. Preferably, the hardening of the surfaces is effected simultaneously by inductive shot hardening.

With regard to joining, it is particularly advantageous to avoid classifying the inner part and the shaft or measuring the opposite and reworking the surface or the mold in the hardened state.

However, an embodiment of the method in which step d) comprises a partial tempering of the blank in the region of a peripheral surface is particularly preferred. This means in particular that only in the region of the raceways of the rolling body is annealed, in the region of the opening of the inner part (near the positive connection), however, no substantial increase in hardness of the starting material is made. This is z. B. the possibility of evacuation of the internal toothing after the partial hardening process in the region of the outer contour or circumferential surface created, which may even be a further stress relief in the interior part when clearing can be effected.

For a (nearly) distortion-free spline can be produced, so that can be dispensed with the classification if necessary. Thus, a locally independent production of inner part and shaft is possible. It should also be mentioned that the spatially limited increase in hardness of the outer contour, with low energy consumption, the desired properties of the tracks can be produced with little delay, wherein at the same time there is a core with very good toughness properties. This property is especially important for joints with a large maximum flexion angle, since the number of punctual force application points is at times very low and large static forces must be absorbed by the remaining rolling elements. This toughness of the material also in the field of splines allows a plastic adaptation when joining with the shaft. This leads to larger contact surfaces and thus to a higher number of bearing feather key / groove connections, so that a better power distribution and a lower notch effect can be realized. In addition, for the (unlikely) case overstressing the positive connection a predetermined breaking point created by the (premature with respect to the shaft) shearing the keys of the inner part, it being ensured that the shaft is securely guided in the opening of the inner part even after such an incident ,

Finally, a vehicle comprising at least one joint produced by a method according to the invention is proposed as a particularly preferred field of application of the invention.

The invention and the technical environment will be explained in more detail with reference to FIGS. It should be noted that the figures show particularly preferred embodiments of the invention, but the invention is not limited thereto. The 1 to 5 show joints that were prepared by the method according to the invention.

Show it:

1 : first embodiment of a joint in section;

2 a spline of a shaft as a side view and in section;

3 a further embodiment of a shaft as a hollow shaft with splines

4 a variant of an inner part in section;

5 a variant of an inner part as a plan view;

6 : schematically a particularly preferred embodiment of the method according to the invention.

With reference to the figures, it should be pointed out that the representations are schematic, that is, limited reference can be made to the size relationships.

1 shows Rzeppa joint fixed design, with only a bending but no displacement of the shaft 6 opposite the joint 1 is possible.

The wave 6 which is the drive side, for example, is in an angled position with respect to the axis 9 of the joint 1 shown. The wave 6 and the axis 9 form a maximum bending angle 8th , which is in an area above 25 ° (preferably above 30 °). The maximum bending angle 8th gets through the shaft 6 and the case 2 determined, wherein at the maximum flexion angle 8th a contact of the wave 6 towards the outer part 2 must be avoided. At the right end of the shaft 6 is a positive connection 7 towards the inner part 3 of the joint 1 realized. This positive, torque-resistant connection, which is preferably designed as a press-fit connection, ensures the transmission of torque from the shaft 6 towards the inner part 3 ,

Between the inner part 3 and the outer part 2 is a cage 4 with a plurality over the circumference of the inner part 3 arranged distributed, here executed as balls, rolling bodies 5 intended. The balls run in corresponding tracks of the inner part 3 and the outer part 2 so they despite a bend angle 8th a torque transmission from the inner part 3 towards the outer part 2 enable. The torque transmission takes place substantially in the circumferential direction, with increasing flexion angle 8th an ever-increasing force in the axial direction of the cage 4 must be recorded.

Since this joint is at least partially provided with supplies such as fats, oils, etc., and also the penetration of dirt is to be prevented, is the joint 1 with a cuff 18 provided on the one hand to the shaft 6 and on the other hand on the outer part 2 is fixed. The transmission of high torques even in extreme positions of the shaft 6 , especially at large bend angles 8th , This ensures that the inner part 3 here a tempered steel with a surface hardness free 10 in the field of positive connection 7 having.

2 shows in a plan view of a shaft end with a connecting portion 15 in which a spline 12 is executed. In the embodiment shown here, the spline has twenty (20) wedges at regular intervals over the circumference of the shaft 6 are arranged distributed. In 2 a cut line is indicated, with the cut in 3 is shown.

In 3 is a section through a variant of the shaft 6 shown. For most applications in the automotive sector, solid waves are preferable, however, hollow shafts can also be used in the joints described here. The wave 6 has a diameter 11 in the range of 15 mm to 40 mm. The on the peripheral surface 16 arranged wedges of the spline 12 have a wedge width 13 and a wedge height 14 on, which can be designed differently according to the loads of the joint. The peripheral surface 16 the spline 12 the wave 6 is preferably inductively surface-hardened, preferably case-hardened in the case of a hollow shaft.

4 shows in a sectional view a first possible embodiment of the inner part 3 , In the sectional view outside are the treads 22 for the rolling elements 5 shown. These treads 22 are with a partial hard layer 23 Mistake. To form such a partial hard layer 23 is the inner part 3 from a directly hardenable steel, in particular a tempered steel. Such an inner part 3 can with for example six (6) or eight (8) treads 22 be executed. Central is an opening 20 , designed here as a passage opening, provided, which at least partially by pushing the shaft 6 allows. To provide a positive, torque-proof connection has the opening 20 on the surface 10 a spline 12 on. This engages in a correspondingly shaped splines 12 the wave 6 , so that the positive connection can be realized.

5 now shows a further embodiment of an inner part 3 , Again, outside are the treads 22 recognizable by webs 28 separated from each other and distributed uniformly over the circumference. In the area of treads 22 in turn became a hard layer 23 provided by inductive partial hardening. At the inner part 3 It is a tempered steel, the surface 10 in the field of positive connection 7 has no cure. The positive connection 7 will turn with a spline 12 ensured at the perimeter of the opening 20 of the inner part 3 is provided.

6 schematically shows a possible sequence of the manufacturing process for a particularly preferred embodiment of the joint 1 , Top in 6 Initially, separate production lines for the individual components are shown schematically, these subsequently being in a production line 29 integrated and to a joint 1 to be assembled. A joint 1 or more joints 1 can then, for example, with a vehicle 30 , in particular the drive train, are combined. The icon above in 6 which the digits 2 . 4 . 5 in particular, illustrates the provision of an outer part 2 , a cage 4 and a plurality of rolling bodies 5 as described in step a) above. The centered rectangle with the numeral 6 illustrates the method step b), which provides the provision of a shaft 6 describes in a connecting portion with a spline 12 is executed. In the lower part of the production line 29 is another rectangle with the numeral 3 represented, which parent the production of an inner part 3 should illustrate.

The individual processes for the production of the inner part 3 are schematically shown below, where the numbering (I) to (V) are to show individual processes of the manufacturing process. With (I) is the production of a blank 19 with an opening 20 represented, wherein this preparation is preferably effected by a forging process. Now the surface will be 10 in the area of treads 22 for the balls of the joint, partially hardened. This includes heating the blank 19 with a coil containing induction heater 25 , wherein the coils are annular here and thus evenly each individual blank 19 specifically heat up (process (II)). This is followed by quenching of the blank 19 by means of a fluid 21 , which consists of a ring shower 21 evenly on the heated outer area of the surface 10 is distributed, which adjusts the desired hardness in this cooling (marked with (III)). After partial hardening, the blank becomes 19 tempered, here while passing the blank on a conveyor belt 27 through an inductive continuous furnace 24 (see (IV)). After starting, the spline becomes 12 through a broaching tool 26 introduced (see process (V)), here is dispensed with a hard machining, because the area near the opening was not cured. Through this production of the inner part 3 in particular also delays of the spline 12 avoided, allowing a joining with the shaft 6 can be made without classification.

LIST OF REFERENCE NUMBERS

1

joint

2

outer part

3

inner part

4

Cage

5

roll body

6

wave

7

connection

8th

flexion angle

9

axis

10

surface

11

diameter

12

spline

13

Key width

14

wedge height

15

connecting portion

16

peripheral surface

17

ring shower

18

cuff

19

blank

20

opening

21

fluid

22

tread

23

hardcoat

24

Continuous furnace

25

induction heater

26

reamer

27

conveyor belt

28

web

29

production line

30

vehicle

31

peripheral surface

Claims (6)

Method for producing a joint ( 1 ) comprising at least one outer part ( 2 ), an inner part ( 3 ), a cage ( 4 ), a plurality of rolling bodies ( 5 ) and a wave ( 6 ), where the wave ( 6 ) and the inner part ( 3 ) a positive connection ( 7 ) and a maximum bending angle ( 8th ) in the range of at least 25 ° to an axis ( 9 ) of the joint ( 1 ), which comprises at least the following steps: a) providing an outer part ( 2 ), a cage ( 4 ) and a plurality of rolling bodies ( 5 ); b) providing a wave ( 6 ) in a connecting section ( 15 ) with a spline ( 12 ) is executed; c) providing a blank ( 19 ) of directly hardenable steel for the inner part ( 3 ) with an opening ( 20 ); d) heat treatment of the inner part ( 3 ), wherein the inner part ( 3 ) with a hardness-free surface ( 10 ) in the region of the positive connection ( 7 ) is executed; e) Provision of the blank ( 19 ) with a spline ( 12 ) in the region of the opening ( 20 ) after step d); f) mounting the components. Method according to claim 1, wherein the blank ( 19 ) during step d) is tempered. The method of claim 1, wherein step d) comprises partially annealing the blank ( 19 ) in the area of the treads ( 22 ). Method according to one of the preceding claims, wherein for the inner part ( 3 ) a tempering steel is used. Method according to one of the preceding claims, wherein for the inner part ( 3 ) a steel having a carbon content in the range of 0.4% to 0.6% is used. Method according to one of the preceding claims, wherein at least for the outer part ( 2 ), the inner part ( 3 ) and the cage ( 4 ) the same material is used.

Images