WO2011134604A1

WO2011134604A1 - Ball pin

Info

Publication number: WO2011134604A1
Application number: PCT/EP2011/001869
Authority: WO
Inventors: Harald Walter; Alexander Paul; Uwe Forthaus
Original assignee: Trw Automotive Gmbh
Priority date: 2010-04-28
Filing date: 2011-04-13
Publication date: 2011-11-03
Also published as: DE102010018643A1

Abstract

The invention relates to a ball pin (28), which comprises a pin stub (10) having a groove (22), and to a method for producing the ball pin (28). The pin stub (10) comprises a groove (22) for retaining a sealing bellows, wherein the groove (22) is produced at least partially by cold free-forming.

Description

ball pin

The invention relates to a ball stud, in particular for a ball joint, and a method for producing such a ball stud.

Ball joints for motor vehicles are protected by means of a sealing bellows or a sealing sleeve against ingress of dirt and moisture or against leakage of joint grease. In this case, two sealing regions occur: on the one hand at the connection of the sealing bellows to the housing, and on the other hand at the connection of the sealing bellows to the ball stud (on which the bellows rotatably moves on the ball stud), hereinafter referred to as

"pin-side seal" refers. In today's standard applications clamping rings can be used for fastening the sealing bellows on the housing or on the ball stud, by means of which the desired sealing effect between the bellows and housing or ball studs supported or

is improved.

For the spigot-side seal, it is necessary that the ball stud or its trunnion has a defined surface, with which the sealing bellows can be sealingly in contact. In most cases, this contact surface of the pin stub is formed as a groove, so that the bellows is positioned on the sealing surface during movements of the pin and can rotate in rotation about the longitudinal axis of the pin. In the assembled state of the ball joint, the sealing bellows or its journal-side sealing seat in the form of a bellows mouth is at least partially in contact with such a groove.

FIGS. 6 and 7 each show conventional ball studs which have a groove 60 for receiving the bellows mouth of a sealing bellows. The production of such a groove can be done by machining.

Alternatively, it is known to produce the trunnion of such a ball stud by cold heading, wherein the contour of the groove by an additional Tool is generated, which is supplied during upsetting laterally, that is approximately at an angle of 90 ° with respect to the longitudinal axis of the pin stub. Under trunnion is the ball stud geometry without the ball to understand. Both of the mentioned production methods are with respect to the required

Processing steps and the necessary tools consuming and increase the manufacturing cost of the trunnion.

FIG. 8 shows a further conventional ball stud which, adjacent to a mounting surface 62, has a contact surface 64 with which a bellows mouth of a sealing bellows can be brought into contact. The ball stud is in a through hole of an assembly body 63 of the vehicle

added. Here, the bellows holding groove 60 is formed with its contact surface 64 between the mounting surface 62 and the mounting body 63. However, the ball stud shown in Fig. 8 is subject to the disadvantage that the contact surface 64 without the mounting body 63, i. ensures no secure axial seating of the bellows mouth in the bellows holding groove 60 without mounting on the vehicle. Furthermore, by the mounting body 63, if it is not exactly matched to the contact surface 64, leakage problems occur.

In the figures 9 and 10 show examples of ball joints with a

conventional ball stud, wherein a sealing bellows 66 is received on the spigot-side seal in a groove 60. The sealing bellows 66 is positioned by the groove 60 axially with respect to the trunnion, with rotatability of the sealing bellows and truncated cone relative to one another being possible. The groove 60 has subsequently been incorporated into the trunnion, which leads to the

already mentioned disadvantages.

Accordingly, the invention has for its object to provide a ball stud and a method for its production, which is possible in a simplified manner. This object is achieved by a ball stud with the features of claim 1 and by a method having the features of claim 8. Advantageous developments of the invention are defined in the dependent claims. An inventive ball pin is particularly suitable for use in a ball joint, and has a trunnion with a groove in which a sealing bellows of the ball joint is positioned or held. The groove is characterized in that it is made at least partially cold-free formed. Preferably, the groove may be bounded in the axial direction of the trunnion by a Materialaufwurf that cold-free formed manufactured and forms an undercut in the axial direction of the trunnion.

The core idea of the invention is that in the ball stud, the groove of the trunnion in the axial direction at least partially cold-free formed or cold-compressed, and this simple or standardized tools that during the molding process only in axial

Direction can be moved substantially in the direction of the longitudinal axis of the trunnion, can be used. To produce the material Aufwurfs a simply designed tool, the undercut or the contour of the groove are formed without an interaction with another tool. In other words, the contour of the groove is only one

Tool half formed in a freeform process, with one

oppositely arranged mold half in a known manner a force acting on the trunnion holding force is ensured. Accordingly, in the formation of the groove, no additional molding tool is inserted into the groove to shape it, i. orthogonal to the longitudinal axis of the trunnion, introduced. As a result, the nature of the tool and the actual molding process for cold-forming the trunnion stump are easy and result in low manufacturing costs of the component.

The ball head is suitably attached to an end region of the trunnion, eg by resistance welding. In an advantageous embodiment of the invention, the groove may be formed in a region of the trunnion, which adjoins the ball head. Accordingly, a bellows mouth of a Sealing bellows are axially positioned in the groove or in this area of the trunnion, which is consistent with the structure of conventional ball joints and the arrangement of the sealing bellows.

In an advantageous embodiment of the invention, the bolt may have a collar portion adjoining the groove, which is arranged on one side of the groove and opposite to the material Aufauf. This has the advantage that only one area of the groove, namely the aforementioned one, due to cold heading

Material throw, with which undercut is generated. The opposite region of the groove is formed or limited by the collar portion, which is usually provided anyway in a bolt in order to connect this suitably with other components. Thus, the collar portion takes a

Double function, whereby the bolt is overall inexpensive to produce.

The ball stud according to the invention is suitable for use in a

Ball joint, which is used in particular for chassis parts of motor vehicles. Such a ball joint comprises a joint housing, which has a Aufnehmung, the above-mentioned ball pin, and a

Sealing bellows with a housing-side seal seat and a

peg-side seal seat in the form of a bellows mouth, wherein the bellows mouth is at least partially in contact with the groove of the trunnion. The

Undercut the groove advantageously leads to the bellows mouth of the

Seal bellows is positioned axially with respect to the trunnion. Accordingly, a Ausknüpfen the Balgmunds from the groove is also effective

prevented if no additional clamping means are used to fix the Balgmunds with respect to the trunnion.

According to a method according to the invention for producing a ball stud, which comprises a truncated cone with a groove, the following steps are

intended:

Providing an elongate metal element, and

Cold forming the metal element in the direction of its longitudinal axis, so that in this case at least a part of the groove and / or a Materialaufwurf which limits the groove, and Attaching a ball head to an end portion of the trunnion.

In a conventional method for producing a truncated cone by cold deformation by upsetting in the axial direction or longitudinal direction of the trunnion usually a tool is used, the two tool halves substantially in the direction of the longitudinal axis of the

Metal element or the trunnion relative to each other and to be moved. The basic idea of the method according to the invention is that the production of the groove or at least a part thereof by a

Cold forming / compression of the metal element takes place solely in the direction of its longitudinal axis, before the ball head is fastened to a front region of the trunnion in a further step. Conveniently, during cold forming of the metal element, a material deployment is created which limits the groove axially. The Materialaufwurf forms in the axial direction of the trunnion

Undercut, which forms part of the contour of the groove.

When performing the axial cold forming of the metal element, a tool with two tool halves is used, which in the direction of

Longitudinal axis of the metal element and are moved in the direction of each other. In an advantageous embodiment of the method according to the invention, the contour of the groove is formed only by a mold half in a free-form process. The feature free-form process in the sense of the invention means that the contour of the tool half, which comes into contact with the truncated cone when forming the groove, does not necessarily have to coincide with the resulting contour of the groove or a part thereof, since the resulting contour of the groove is solely from upsetting or cold forming of the metal element results.

In an advantageous development of the method according to the invention, the contour of the groove is produced during cold forming of the metal element, without a mold being introduced into the groove for its shaping, ie from a direction transverse to the longitudinal axis of the metal element. As a result, the Zapfen stump is made exclusively by tool movements, which take place in the direction of the longitudinal axis of the trunnion. That way is the Forming process and the associated machine technology simple and inexpensive.

The elongated metal element is expediently a rotationally symmetrical standard body which has no undercut. Such a standard body can be obtained starting from a semifinished product, e.g. in the form of a metal wire or the like also by an axial

Cold forming or upsetting alone in the axial direction, ie. in the direction of the longitudinal axis of the metal wire. The standard body without the

Undercut may, for example, a stepped portion in the form of a shoulder portion or the like, with which a tool for a subsequent cold forming of the metal element for generating at least a part of the groove and / or the Materialaufwurfs come into contact.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

The invention is illustrated schematically below with reference to an embodiment in the drawing and is with reference to the drawing

described in detail.

Show it:

Figure 1 is a side view of an inventive

Zapf cone,

FIG. 2 shows a sequence of steps, such as is produced from an elongated metal element by means of an axial cold-forming of the trunnion stump according to FIG. 1,

Figure 3a is a side view of a trunnion and one of them

separate ball head, Figure 3b is a side view of a ball stud, wherein the

Trunnion stump and the ball head according to Figure 3a are suitably fastened together,

4, 5 different embodiments of a ball joint with a ball stud according to Figure 3b,

Figures 6-8 conventional ball studs according to the prior art, and Figures 9, 10 conventional ball joints according to the prior art.

Figure 1 shows a side view of a trunnion 10, the part of a

Ball stud 28 according to the invention (Figure 3b). The trunnion 10 is rotationally symmetrical with respect to its longitudinal axis 12. The trunnion 10 has a first end portion 14 which is provided for attachment of a ball head 30 (Figure 3a). The trunnion 10 has approximately in a central region a collar portion 20 which represents the maximum diameter region of the bolt 10. Below the collar section 20, in the direction of a lower second end region 16, may be on the trunnion 10th

Connecting means may be provided in the form of a thread 18 or the like, by means of which the trunnion 10 is connectable to other components.

Adjacent to the second end portion 16, the trunnion 10 has a

Attack surface 19 for a mounting tool on.

The collar portion 20 may form a contact area, by means of which the trunnion 10 can be brought to rest on other components, so that a suitable power transmission between the trunnion 10 and these components is ensured. Between the collar portion 20 and the first end portion 14, the trunnion 10 has a groove 22 which is bounded by a material Aufauf 24. The Materialaufwurf 24 forms in the axial direction of the trunnion 10 an undercut whose function is explained below in detail. 1 illustrates that the groove 22 is formed between the material throw-up 24 and the collar portion 20, wherein an edge region of the collar portion 20 is the material throw 24

opposite. The Materialaufwurf 24 and thus the upper portion of the groove 22 are

According to the invention produced by an axial cold upsetting of the trunnion 10 in the direction of its longitudinal axis 12. Figure 2 illustrates a

Manufacturing process for the formation of the material Aufaufs 24.

The manufacture of the trunnion 10 begins with the provision of a metal element in the form of a blank, for example a piece of metal wire 8, shown in Figure 2 above. For simplicity, such a metal element is always referred to hereinafter as a wire, without being limited thereto. The wire 8 is elongated and cylindrical, thus rotationally symmetrical. In a known manner, the wire 8 is first formed by axial compression or axial cold forming to form an intermediate product 9 (FIG. 2, middle view) which has no undercuts. By means of such axial compression two halves of a tool in a known manner in

moves several steps relative to each other and thereby open and closed, namely in the direction of arrow A of Figure 2. The movement of the tool halves is thus in the direction of the longitudinal axis 12 of the wire eighth

The intermediate product 9 is shown in the middle in FIG. In this case, in the section between the first end region 14 and the collar section 20, a shoulder section 26 is formed whose diameter increases starting from the first end section 14 in the direction of the collar section 20. The shoulder region 26 goes in the direction of the collar portion 20 in a

Bolt section 27 via. In other words, the bolt portion 27 is disposed between the shoulder portion 26 and the collar portion 20. The bolt portion 27 and the shoulder portion 26 fulfill in the production of the groove 22 has an essential function, wherein the bolt portion 27 in this case forms a Anbind ungsfläche for positioning of other components.

Starting from the intermediate product 9, a suitable tool is placed on the wire or bolt 10 from the direction of the first end region 14 in a next step. This tool comes into contact with the shoulder portion 26. By an axial movement of the tool (in the direction 2) downwards, ie in the direction of the collar portion 20, the shoulder portion 26 is reshaped to the Materialaufwurf 24, so that from the pin portion 27, the groove 22 is generated. The shape of the groove 22 depends on the existence and the configuration of the bolt portion 27 and the material Aufaufs 24. It is important that the bolt portion 27 has a sufficient length in the direction of the longitudinal axis of the wire 8, so that between the material throw 24 and the collar portion 20, the groove is formed. In contrast, the shoulder portion 26 may not be directly in the

Pass collar section 20.

In Fig. 2, the groove 22 and the Materialaufwurf 24 are shown in the finished state in the lower picture. The Materialaufwurf 24 forms an undercut in the axial direction of the bolt 10, so that there is the groove 22 in interplay with an edge region of the collar portion 20 thereof.

With regard to the deformation of the shoulder portion 26 by the tool, it should be understood that this is a free-form process. This means that, when the shoulder section 26 is deformed by the tool, the contour of this area of the groove 22 is formed independently, without any impact

Contact area of the tool with the resulting contour of the groove

is complementary. It is understood that during cold diving of the

Shoulder section 26 through the tool another tool half in

Contact with the bolt 10 passes, for example at a lower edge of the collar portion 20, wherein this edge of the collar portion 20th

opposite to the shoulder portion 26. By means of this further

Tool half, which is in contact with the lower portion of the collar portion 20, a necessary counter-holding force is generated. This further tool half does not come into direct contact with the shoulder portion 26 and therefore is not involved in the freeform process for the material disposal 24.

FIGS. 3 a and 3 b show the ball pin 28 according to the invention, which is formed from the pin stump 10 according to FIG. 1 and a ball head 30. In Figure 3a, the trunnion 10 and the ball head 30 are separated shown from each other. In this regard, it should be understood that the trunnion 10 is first made as a separate component, in correspondence with FIG

The sequence of steps of Figure 2. Only after the trunnion 10 of Figure 2 is completed is the ball head 30 properly coupled to the first end portion 14 of the trunnion 10, i. connected to the end face or fastened thereto, for example by welding, expediently in the form of resistance welding. In Figure 3b, the ball stud 28 is in finished

State shown when the ball head 30 is fixed to the trunnion 10.

FIG. 4 shows a usage example of the ball stud 28 according to FIG. 3b, namely a ball joint 32, which is shown in a longitudinal section.

Below are the essential functional elements of such

Called and explained ball joint 32 in detail.

The ball joint 32 comprises a housing 34, which has a recess 36 in the form of a passage opening. The ball pin 28 is locked with its ball head 30 by means of a joint shell 38 in the recess 36 of the joint housing 34. A force and / or positive positioning of the joint shell 38 within the recess 36 is ensured by suitable snap hooks 40 which are latched to an edge 37 of the recess 36.

To seal the ball joint 32, a sealing bellows 42 is provided, which is suitable for the penetration of dirt or moisture into the interior of the

Ball joint 32 prevented. Similarly, the sealing bellows 42 excludes the leakage of grease or the like from the interior of the ball joint 32. By means of a formed at its upper edge 43 recess 44 in the form of a groove of the sealing bellows 42 with a retaining flange 46 of

Joint shell 38 connected or linked. The lower edge of the sealing bellows 42 in the form of a bellows mouth 48 is sealingly in contact with the groove 22 of the ball stud 28th

The longitudinal sectional illustration of FIG. 4 clarifies that the bellows mouth 48 is disposed within the groove 22, which is defined by an edge region of the collar section 20 and the undercut of the Materialaufwurfs 24 is formed, is held positionally secure with respect to the ball stud 28. This means that one

reliable sealing seat of Balgmunds 48 is also ensured within the groove 22 when the ball pin is pivoted with its longitudinal axis 12 relative to the joint housing 24 and thereby the sealing bellows 42 is deformed.

In Figure 5 is a longitudinal sectional view of another example of a

Ball joint 32 shown. The only difference in comparison with the ball joint 32 according to Figure 4 is that the bellows mouth 48 is additionally secured by a clamping ring 50 which surrounds the bellows mouth 48 at its periphery. The clamping ring 50 thus improves the fit of the bellows mouth 48 within the groove 22 and effectively prevents the bellows mouth 48 from being unloughed out of the groove 22. Otherwise, the ball joint of FIG

Ball joint of Figure 4 identical, so reference is made to avoid repetition.

Claims

Ball stud (28) comprising

a trunnion (10) having a groove (22) for holding a sealing bellows, wherein the groove (22) is made at least partially cold-free formed, and

a ball head (30) secured to the trunnion (10).

Ball pin (28) according to claim 1, characterized in that the groove (22) is formed in a region of the pin stub (10) which is adjacent to the ball head (30).

Ball stud (28) according to claim 1 or 2, characterized in that the groove (22) in the axial direction of the trunnion (10) by a material Aufauf (24) is limited, which is made cold-free formed and an undercut in the axial direction of the trunnion (10) forms.

Ball pin (28) according to claim 3, characterized in that the material Aufauf (24) by cold freeforming in the axial direction of the trunnion (10) is made.

Ball stud (28) according to claim 3 or 4, characterized in that the trunnion (10) has a collar portion (20) which adjoins the groove (22) and at a the material Aufwurf (24)

opposite side of the groove (22) is arranged.

Includes ball joint (32), in particular for chassis parts of motor vehicles

a joint housing (34) having a recess (36), a ball stud (28) according to one of claims 1 to 5, a sealing bellows (42) having a housing-side seal seat and a journal-side seal seat in the form of a bellows mouth (48) at least partially in contact with the groove (22).

Ball joint (32) according to claim 6, characterized in that the undercut fixes the bellows mouth (48) axially with respect to the trunnion (10).

Method of making a ball stud having a trunnion stub

(10) with a groove (22), comprising the steps of:

Providing an elongated metal element (8, 9),

Cold forming of the metal element (8, 9) in the direction of its longitudinal axis

(12), so that at least a part of the groove (22) and / or a

Materialaufwurf (24), which limits the groove (22) axially generated, and

Attaching a ball head to an end portion of the trunnion (10).

A method according to claim 8, characterized in that at

Cold forming the metal element (8, 9) two opposite

Tool halves are moved substantially in the direction of the longitudinal axis (12) of the metal element and in the direction relative to each other, wherein the contour of the groove (22) only of a mold half in one

Freeform process is formed.

A method according to claim 8 or 9, characterized in that during cold forming of the metal element (8, 9), the contour of the groove (22) is generated, without causing a mold into the groove (22) to the

Shaping from a direction transverse to the longitudinal axis (12) of the

Trunnion (10) is introduced.

A method according to claim 9 or 10, characterized in that the contour of the mold half, during cold forming of the metal element (8, 9) comes into contact with the resulting contour of the groove (22) is not complementary.

Method according to one of claims 8 to 10, characterized in that the metal element (8, 9) is a rotationally symmetrical body without undercut.