Abstract
A protective cap (1, 30) for covering some areas of a fully assembled ball joint (50). The protective cap (1, 30) can be screwed, by virtue of a multi-turn, all-round internal thread (11), onto a threaded section (53) of a ball stud (51) of the ball joint (50). Furthermore, a ball joint (50) with a ball stud (51) having a protective cap (1, 30) screwed onto a threaded section (53) of the ball stud (51). Also a two-point linkage (80) with at least one ball joint (81, 82) having a ball stud (51) with a protective cap. The linkage is in the form of a steering rod (80), a track rod, a stabilizer tie-rod, an operating link or a Panhard rod.
Claims
1-13. (canceled)
14. A protective cap (1, 30) for covering some areas of a fully assembled ball joint (50), the protective cap (1, 30) being screwed, by virtue of a multi-turn all-round internal thread (11), onto a threaded section (53) of a ball stud (51) of the ball joint (50).
15. The protective cap (1, 30) according to claim 14, wherein an outer circumference of the protective cap (1, 30) has at least one grip-enabling geometrical feature (4, 5), which is suitable for the interlocked application of a torque acting in a direction of the outer circumference.
16. The protective cap (1, 30) according to claim 15, wherein the grip-enabling geometrical feature is in the form of at least one of a regular polygon (4) and at least one wing (5).
17. The protective cap (1, 30) according to claim 14, wherein the protective cap (1, 30) is reinforced in some areas by a rib structure (6, 7, 36) to increase rigidity thereof.
18. The protective cap (1, 30) according to claim 14, wherein the protective cap (1, 30) has a radially circumferential first sealing surface (16) that extends perpendicularly to a centerline (3) of the protective cap and which forms a seal against a sealing bellows (59) of the ball joint (50).
19. The protective cap (1, 30) according to claim 14, wherein an inside circumferential surface (19) of the protective cap (1, 30) has a radially circumferential second sealing surface (22) that mates with the ball stud (51).
20. The protective cap (1, 30) according to claim 19, wherein the second sealing surface (22) forms an end-stop for the screwing of the protective cap (1, 30) onto the ball stud (51).
21. The protective cap (1, 30) according to claim 4, wherein the protective cap (1, 30) has at least one drainage opening (10).
22. The protective cap (1, 30) according to claim 18, wherein the protective cap (1, 30) is made completely closed in a lower section (13) of the protective cap, which extends from the first sealing surface (16) down to a bottom (15) at an end of the protective cap (1, 30).
23. A ball joint (50) with a ball stud (51), the ball joint comprising: a protective cap (1, 30) for covering some areas of a fully assembled ball joint (50), and the protective cap (1, 30) being screwed by virtue of a multi-turn all-round internal thread (11) onto a threaded section (53) of the ball stud (51) of the ball joint (50).
24. The ball joint (50) according to claim 23, wherein the ball joint (50) has a sealing bellows (59), and the screwed-on protective cap (1, 30) leaves a portion of the sealing bellows (59) exposed.
25. The ball joint (50) according to claim 24, wherein when the protective cap (1, 30) is screwed onto a threaded section (53) of the ball stud, the sealing bellows (59) is held in a fitted position by a first sealing surface (16) of the protective cap (1, 30).
26. A two-point linkage (80) with at least one ball joint (50) having a ball stud (51) and a protective cap (1, 30) for covering some areas of a fully assembled ball joint (50), the protective cap (1, 30) being screwed by virtue of a multi-turn all-round internal thread (11) onto a threaded section (53) of the ball stud (51) of the ball joint (50), and the two-point linkage being one of a steering rod (80), a track rod, a stabilizer tie-rod, an operating link, and a Panhard rod.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Below, the invention is explained in more detail with reference to drawings that illustrate embodiments presented only as examples. The same indexes refer to the same components or elements in the drawings, which show:
[0029] FIG. 1: A perspective view of a protective cap according to a first embodiment of the invention;
[0030] FIG. 2: A sectioned view of the protective cap shown in FIG. 1;
[0031] FIG. 3a: An enlarged view of the detail X in FIG. 2, in which the protective cap is rotated slightly about the central axis;
[0032] FIG. 3b: A detailed view as in FIG. 3a, supplemented by a ball stud;
[0033] FIG. 4: A perspective view of a protective cap according to a second embodiment of the invention;
[0034] FIG. 5: A sectioned view of a ball joint with a protective cap according to the first embodiment;
[0035] FIG. 6: An enlarged view of the detail Y in FIG. 5;
[0036] FIG. 7: A partially sectioned view of a two-point linkage with ball joints arranged at its ends.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0037] FIG. 1 shows a first embodiment of an integrally formed protective cap 1, made of plastic by a plastic injection-molding process. By the nature of the process the protective cap 1 has mold-parting burrs 2 that extend in a common plane with the centerline 3 of the protective cap 1. To facilitate the interlocked application of a torque acting in the direction of the outer circumference of the protective cap 1, the protective cap has a grip-enabling geometry in the form of a regular polygon, in this case a double hexagon 4, and a pair of radially opposed wings 5, one of which wings is not visible in the figure. The double hexagonal gripping geometry 4 is provided for the screwing on and off of the protective cap 1 using a screwing tool and the wings 5 for screwing it on and off by hand. To increase its rigidity the protective cap is reinforced by two rib structures 6, 7, each of the rib structures 6, 7 being formed by a plurality of individual ribs 8, 9. For use in a pretreatment unit that works with water-based cleaning and rinsing media, and in a phosphating unit, the protective cap 1 is provided with a number of drainage openings 10 which allow liquid media to drain away during the production process.
[0038] In FIG. 2 it can be seen that the protective cap 1 has a multi-turn internal thread 11. The internal thread 11 is a right-hand, fine-pitch thread formed to go round without interruption over about 1.5 thread pitches. In the axial direction 12 of the protective cap 1 a lower section 13 in which the internal thread is located is attached to an upper section 14 of the protective cap. The lower section 13, which is completely closed, has a bottom 15 at an end of the protective cap 1. The upper section 14, which is separated from the lower section 13 by a first sealing surface 16, has an assembly opening 17 at its end in the axial direction 12 and opposite the bottom 15. The protective cap 1, shaped overall like a cup with a surrounding wall 18, has in its upper section 14 the drainage openings 10 that pass through the wall 18, which are distributed uniformly around the circumference of the protective cap. The upper section 14 is reinforced on the inside circumferential surface 19 of its wall 18 by the rib structure 6 formed of a plurality of ribs 9 distributed uniformly around the circumference and extending in the axial direction 12, the ribs 9 being formed integrally with the wall 18. Furthermore the upper section 14, whose diameter is larger than that of the lower section 13, is also reinforced by a further rib structure 7. This further rib structure 7 is formed of a plurality of ribs 8 arranged on the outer circumferential surface 20 of the wall 18 and connected integrally thereto. The ribs 8 extend in the circumferential direction all round the protective cap 1 and are arranged in parallel planes a distance apart which extend perpendicularly to the centerline 3 of the protective cap 1. On the side of the bottom 15 opposite the internal thread 11 the lower section has a hollow-cylindrical section 21 whose inside diameter is around 0.3 millimeters larger than the outer diameter of the internal thread 11.
[0039] In FIG. 3a it can be seen that at one free end of the inner circumferential surface 19 there is arranged a second sealing surface 22 which extends radially all the way round. The first sealing surface 16 is in the form of a circular ring surface interrupted by a radial all-round recess 23. Thus, the first sealing surface 16 is divided into two concentrically arranged circular ring surfaces a distance away from one another. The innermost of these two circular ring surfaces is part of an annular all-round web 24 which is an integral part of the protective cap 1 and is arranged between the inner circumferential surface 19 and the recess 23. Owing to its relatively small wall thickness of 0.8 millimeters in the area of the second sealing surface 22, the web 24 has some elasticity. Thanks to that, the second sealing surface 22, which is also part of the surface of the web 24, can fit very snugly to form a seal against a ball stud 51 close to it in the assembled condition. In the axial extension of the inner circumferential surface 19 of the protective cap 1 a conical section 26 is adjacent to the second sealing surface 22, separated therefrom by a transition radius.
[0040] For the sake of clarity FIG. 3b shows the arrangement already illustrated in FIG. 3a, supplemented by the ball stud 51. The second sealing surface 22, whose axial extension of one millimeter is relatively small, at the same time forms a first contact surface 69 with a conical section 64 of the ball stud 51. During the fitting of the protective cap 1 this is displaced relative to the ball stud 51 by being screwed onto the ball stud 51. During this the at first still undeformed second sealing surface 22 of the protective cap 1 comes into contact with the conical section 64 initially with the free end of the inner circumferential surface 19 in an all-round line contact in the form of a circular line 25. As the screwing on continues, the diameter of the conical section 64 of the ball stud 51 continually increases. Since the second sealing surface 22 is in the form of an outer surface of a cylinder with a certain elasticity, as the screwing on continues an all-round surface contact is formed between the second sealing surface 22 of the protective cap 1 and the conical section 64 of the ball stud 51. During this the second sealing surface 22, which in the undeformed condition was in the form of a cylindrical outer surface, is deformed elastically essentially into the shape of an outer surface of a cone which fits in a shape-matching manner against the conical section 64 of the ball stud 51. In this assembled condition the conical section 26 of the protective cap 1 is separated from the conical section 64 of the ball stud 51 by circumferential ring gap 27. Thus, the second sealing surface 22 in contact with the conical section 64 of the ball stud 51 at the same time functions as an end-stop for the screwing of the protective cap 1 onto the ball stud 51. Although the web 24 on the one hand has a certain elasticity which enables the full-area contact of the second sealing surface 22 against the conical section 64 of the ball stud 51, the closed-ring structure of the web 24 results in a minimal flexibility in relation to the function of the second sealing surface 22 as an end-stop.
[0041] FIG. 4 shows a protective cap 30 according to a second embodiment. In its upper part 33, to improve the heat insulation the wall 34 of the protective cap 30 is surrounded by an additional wall 35 concentrically around and a distance away from the wall 34, this additional wall 35 being in the form of a cylindrical ring. The also cylindrical-ring-shaped intermediate space between the wall 34 and the additional wall 35 is bridged by a fin structure 36 whose fins 37 extend in the axial direction 38 of the protective cap 30 and are distributed uniformly around the circumference. Other details of the structure of the protective cap 30 correspond to the first embodiment, which is described above and illustrated in FIGS. 1 to 3.
[0042] FIG. 5 shows a ball joint 50 in the form of a radial ball joint with the ball stud 51, wherein a protective cap 1 according to the first embodiment as described above is screwed onto a threaded section 53 of the ball stud 51. Alternatively it is also possible to screw a protective cap according to the second embodiment onto the threaded section 53 of the ball stud 51. The ball joint 50 is a fully assembled ball joint, which is functional and ready to be fitted in a vehicle. The threaded section of the ball stud 51 has an external thread 54. The extension of the external thread 54 in the direction of the central axis 55 of the ball joint 51 is larger than the extension of the internal thread 11 of the protective cap 1 in the same direction. The external thread 54 and the internal thread 11 fit one another and form a right-hand, fine-pitch screw connection. The inside diameter of the area of the protective cap 1 which surrounds the external thread 54 but is not part of the internal thread, is 0.3 millimeters larger than the outer diameter of the external thread 54 of the threaded section 53. This relatively close guiding ensures that while the protective cap 1 is being screwed onto the threaded section 53 of the ball stud 51 it cannot tilt. When the protective cap 1 has been screwed on, the inside of the bottom 15 of the protective cap 1 is a distance away from an end of the ball stud 51 opposite it. This clearance ensures that the second sealing surface 22 can form an end-stop for the screwing of the protective cap 1 onto the ball stud 51.
[0043] The ball joint 50 has a sealing bellows 59, although the screwed-on protective cap 1 leaves part of the sealing bellows 59 clear. The sealing bellows 59 is designed rotationally symmetrically and is clamped at a section at its front end to a housing 61 of the ball joint 50 by means of a clamping ring 60. This front end section of the sealing bellows 59, and with it the clamping ring 60, are not covered by the protective cap 1, so that during a painting step the clamping ring 60 can be provided with additional surface protection without having to screw off the protective cap 1 to make that possible. At one end, the ball stud 51 has a joint ball 62 which is fitted and able to rotate and pivot in the housing 61 of the ball joint 50. The threaded section 53 is arranged at the end of the ball stud 51 opposite the joint ball 62. The housing 61 of the ball joint 50 is made integrally with a shaft 66 for connecting the ball joint 50 to a connecting tube 83 of a two-point linkage 80.
[0044] When the protective cap 1 is screwed on, the sealing bellows 59 is held in its fitted position by the protective cap 1, in particular by the first sealing surface 16 thereof. The conical section 64 of the ball stud 51 tapers down in the direction toward the threaded section 53. In contact with the outer circumference of this conical section 64 is a lower end section 65 of the sealing bellows 59, which lower end section 65 is opposite the end section of the sealing bellows 59 clamped to the housing 61. The inside wall of the lower end section 65 is in contact with the conical section 64 of the ball stud 51, forming a second contact surface 67. The first sealing surface 16 of the protective cap 1 is in contact with an end surface of the lower end section 65 of the sealing bellows 59, forming a third contact surface 68. The end surface has a labyrinth seal, which is shown in its slackened condition and which therefore overlaps with the first sealing surface 16. The first contact surface 16, in which the second sealing surface 22 contacts and forms a seal against the outer circumference of the conical section 64 of the ball stud 51, is adjacent to the second contact surface 67 and is arranged essentially as an extension thereof. The first contact surface 69 and the second contact surface 67 are at least substantially perpendicular to the third contact surface 68, so that an end in each case of the first 69, second 67 and third 68 contact surfaces shown in FIG. 6 meet at a point. To protect the surface of the ball stud 51 that projects out of the sealing bellows 59 against corrosion, in particular caused by contact with corrosively acting liquid media, the protective cap 1 is made completely closed between the first sealing surface 16 and the bottom 15.
[0045] FIG. 7 shows a two-point linkage designed as a steering rod 80, at whose ends two fully assembled ball joints 81, 82 as described above are arranged. The ball joints 81, 82 are connected to one another by means of a connecting tube 83. To cover some parts of it a protective cap 1 according to the first embodiment described previously and illustrated in FIGS. 1 to 3 is screwed onto the first 81 of the two ball joints. The first ball joint 81 has a shaft (only partly visible) with an external thread extending in its longitudinal direction. The second 82 of the two ball joints has a shaft 85 which is connected to the connecting tube 83 by means of a hot swaging process. During the hot swaging the associated end section of the connecting tube 83 is brought into engagement with the serrated structure. In order to protect the second ball joint 82, in particular the sealing bellows 59 (not visible) of the second ball joint 82 against damage due to process-related radiant heat at the joint location during the hot swaging, a heat-insulating protective cap 30 according to the second example embodiment described earlier and illustrated in FIG. 4 is screwed onto the second ball joint 82. The ball joints 81, 82 differ from the previously mentioned ball joint 50 only in the structure of their shaft.
INDEXES
[0046] 1 Protective cap [0047] 2 Mold-parting burr [0048] 3 Centerline [0049] 4 Polygon, double hexagon [0050] 5 Wing [0051] 6 Rib structure [0052] 7 Rib structure [0053] 8 Rib [0054] 9 Rib [0055] 10 Drainage opening [0056] 11 Internal thread [0057] 12 Axial direction [0058] 13 Lower section [0059] 14 Upper section [0060] 15 Bottom [0061] 16 First sealing surface [0062] 17 Assembly opening [0063] 18 Wall [0064] 19 Inside circumferential surface [0065] 20 Outer circumferential surface [0066] 21 Hollow-cylindrical section [0067] 22 Second sealing surface [0068] 23 Recess [0069] 24 Web [0070] 25 Linear contact, circular line [0071] 26 Conical section [0072] 27 Annular gap [0073] 30 Protective cap [0074] 33 Upper section [0075] 34 Wall of the protective cap [0076] 35 Additional wall [0077] 36 Fin structure [0078] 37 Fin [0079] 38 Axial direction [0080] 50 Ball joint [0081] 51 Ball stud [0082] 53 Threaded section [0083] 54 External thread [0084] 55 Central axis [0085] 59 Sealing bellows [0086] 60 Clamping ring [0087] 61 Housing [0088] 62 Joint ball [0089] 64 Conical section [0090] 65 Lower end section [0091] 66 Shaft [0092] 67 Second contact surface [0093] 68 Third contact surface [0094] 69 First contact surface [0095] 80 Two-point linkage, steering rod [0096] 81 First ball joint [0097] 82 Second ball joint [0098] 83 Connecting tube [0099] 85 Shaft
