US20050036827A1

US20050036827A1 - Ball and socket joint protective cap

Info

Publication number: US20050036827A1
Application number: US10/952,314
Authority: US
Inventors: Manfred Bohne; Carsten Spremberg
Original assignee: ZF Lemfoerder GmbH
Current assignee: ZF Lemfoerder GmbH
Priority date: 2002-09-11
Filing date: 2004-09-28
Publication date: 2005-02-17
Also published as: HK1080536B; KR20050065452A; CN1639474A; HK1080536A1; CN1330889C; DE10242578B4; WO2004027275A1; EP1537338A1; DE10242578A1; JP2005538328A

Abstract

A ball and socket joint protective cap is provided for covering the pin-shaped partial area (7) of a completely mounted ball and socket joint. At least two hollow cylindrical sections (12, 13) of different diameters are arranged adjacent in the axial longitudinal direction of the ball and socket joint protective cap (11). The section (12) with the larger diameter is arranged at the end of the ball and socket joint protective cap (11) that is to be attached to the joint housing (1). For the better protection of the completely mounted ball and socket joint with the ball and socket joint protective cap (11) attached, the ball and socket joint protective cap has a transition area (16) extending essentially at right angles to the axial longitudinal direction of the ball and socket joint protective cap (11) in the transition of the hollow cylindrical sections (12, 13), wherein the dimension of the diameter of the smaller hollow cylindrical section (13) of the ball and socket joint protective cap (11) is only slightly larger than the dimension of the covered conical receiving section (8) of the pivot pin (3) of the ball and socket joint. Displacement of the sealing bellows (5) of the ball and socket joint in the direction of the arrows P is achieved due to this special design during the attachment of the ball and socket joint protective cap to the pin-shaped partial area of the pivot pin, as a result of which the pressing forces are increased in the area of the contact surface between the sealing bellows (5) and the pivot pin (3).

Description

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation of and claims the benefit (35 U.S.C. §120 and 365(c)) of copending International Application PCT/DE 2003/003010 of Sep. 10, 2003, which designated inter alia the United States and which claims the priority of German Application DE 102 42 578.7 of Sep. 11, 2002. The entire contents of each application is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention pertains to a ball and socket joint protective cap for covering the pin-shaped partial area of a completely mounted ball and socket joint for the period from the manufacture to the installation of the ball and socket joint, the ball and socket joint being provided with a joint housing and a pivot pin accommodated pivotably therein.

BACKGROUND OF THE INVENTION

Ball and socket joints in which the ball and socket joint protective cap of this type is used usually comprise a joint housing and a pivot pin accommodated within the joint housing by means of a bearing shell. The pivot pin comprises a spherical bearing surface as well as a pin-shaped partial area, which extends at it in the axial longitudinal direction of the pivot pin and protrudes from the joint housing in the completely mounted state of the ball and socket joint. A conical receiving section for fixing the ball and socket joint at another component, for example, a chassis-side component of a motor vehicle, as well as a threaded section, which is usually provided for fixing and is provided with external threads, are usually present on this pin-shaped partial area. Another component of such ball and socket joints is a sealing bellows, which seals the gap between the housing and the pivot pin protruding from an opening of the housing. The sealing bellows is usually fixed statically at the housing and is arranged on the conical receiving section of the pivot pin displaceably in the axial longitudinal direction of the pivot pin and extending around same.
Usual ball and socket joint protective caps have at least two adjacent sections of different geometries, the section with the larger external dimension being attached to the housing of the ball and socket joint to be protected, adjacent to the edge area of the opening for the pivot pin.
The transition area between the individual sections may have a conical design in order to guarantee a sufficient distance from the components of the ball and socket joint that are to be protected. The outer end of the ball and socket joint protective cap is closed by a cap-like section, so that a closed interior space is obtained for the protection of the pin-side partial area and of the sealing bellows after the ball and socket joint protective cap has been attached to the joint housing.
In practice, the above-described ball and socket joint protective caps known so far have the drawback that moisture and dirt penetrate into the ball and socket joint especially during the transportation of the ball and socket joints despite the ball and socket joint protective caps attached.

SUMMARY OF THE INVENTION

The object of the present invention is therefore to provide a ball and socket joint protective cap of the type of this class, which guarantees reliable protection of both the sealing bellows against the action of external forces and an additional protection of the gap between the pin part and the housing against dirt.
According to the invention, a ball and socket joint protective cap is provided for covering the pin-shaped partial area of a completely mounted ball and socket joint, which is provided with a joint housing and a pivot pin accommodated pivotably therein. The protective cap is attached to the pivot pin of the ball and socket joint with at least two sections of different geometries, which are arranged adjacent in the axial longitudinal direction of the ball and socket joint protective cap. The section with the larger outer dimension is arranged at the end of the ball and socket joint protective cap, which said end faces the joint housing. A transition area extends essentially at right angles to the axial longitudinal direction of the ball and socket joint protective cap. The transition area is arranged at the transition of the sections.
The displaceable sealing bellows located on the pivot pin is displaced due to this design embodiment in the direction of the joint housing due to the transition area extending at right angles to the axial longitudinal direction when the ball and socket joint protective cap is attached to the pin-shaped partial area of the ball and socket joint; this displacement leads to a deformation of the sealing bellows, as a result of which the sealing bellows becomes axially pretensioned and, as a result of this, the pressing forces increase as a consequence of the radial pretension of this component at the pivot pins of the ball and socket joint. This result guarantees an increased sealing action and prevents contaminants of any kind from penetrating into the interior of the ball and socket joint.
Moreover, an additional sealing surface is created due to the fact that the transition area of the ball and socket joint protective cap extending at right angles to the axial direction is in contact with the outer edge of the sealing bellows, so that the outer area of the sealing bellows is also protected from contaminants as long as the ball and socket joint protective cap is attached to the ball and socket joint if the protective cap of the ball and socket joint is at the same time in contact with the housing.
It has proved to be advantageous, in particular, to design the sections of the ball and socket joint protective cap as hollow cylindrical sections, where the dimension of the diameter of the smaller hollow cylindrical section of the ball and socket joint protective cap should be only slightly larger than the dimension of the covered, pin-shaped partial area of the ball and socket joint.
Another embodiment of the present invention can be seen in the fact that three hollow cylindrical sections of different diameters are provided over the overall axial length of the ball and socket joint protective cap, wherein the diameter values of the individual sections decrease from the end to be attached to the housing to the opposite free end of the ball and socket joint protective cap, and a transition area extending essentially at right angles to the axial longitudinal direction of the ball and socket joint protective cap is arranged in the transition area of the hollow cylindrical sections.
Based on this design, an additional step, which can bring about an additional sealing action in conjunction with the ball and socket joint to be protected, is thus created at the ball and socket joint protective cap in addition to the technical teaching described in claim 1. This happens due to the fact that the step created additionally is present at a recess usually present at the ball and socket joint in the area between the conical receiving section of the pivot pin and the threaded section adjoining same toward the free end. Two annular sealing surfaces are thus formed between the ball and socket joint protective cap and the pivot pin.
It has proved, moreover, to be advantageous that at least one radially inwardly projecting elastic tongue, which may be designed as a tongue extending circularly over the entire inner contour if necessary, is arranged at the inner contour of the hollow cylindrical section located at the free end of the ball and socket joint protective cap, which said free end faces away from the joint housing. This tongue engages a thread of the threaded section of the pivot pin enclosed by the hollow cylindrical section in question and thus ensures a reliable fixation of the ball and socket joint protective cap on the pin-shaped partial area of the pivot pin, and fixation of the ball and socket joint protective cap at the housing can thus be dispensed with.
An increase in the elasticity of the circular tongue can be brought about as an additional expedient embodiment by the radially inwardly projecting elastic tongue having a plurality of slots distributed over the entire circumference of the tongue.
Corresponding to an advantageous variant, the pulling off of the ball and socket joint protective cap is facilitated in that at least one radially outwardly projecting step, which may extend circularly, is arranged at the outer edge of the hollow cylindrical section located at the free end of the ball and socket joint protective cap, which said free end faces away from the joint housing.
An exemplary embodiment of the subject of the present invention will be explained in greater detail below on the basis of the drawings attached. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a conventional ball and socket joint with a ball and socket joint protective cap according to the present invention attached to it;
FIG. 2 is a sectional view of the ball and socket joint protective cap alone; and
FIG. 3 is a top view of the ball and socket joint protective cap corresponding to arrow B from FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The ball and socket joint shown in FIG. 1 is formed essentially from a joint housing 1, a bearing shell 2 located in an inner cavity of the joint housing, a pivot pin 3 accommodated within the bearing shell, a closing ring 4 as well as a sealing bellows 5. The pivot pin 3 has a ball head 6 as well as a pin-shaped partial area 7, wherein the pin-shaped partial area 7 is in turn divided into a conical receiving section 8 as well as a threaded section 9. After the final mounting of the entire ball and socket joint, especially the cavity 10 between the sealing bellows 5 and the pivot pin 3 and the outer side of the sealing bellows 5 as well as the pin-shaped partial area 7 are to be protected from contaminants and damage as a consequence of mechanical loads during the transportation. After its manufacture, the ball and socket joint is provided with a ball and socket joint protective cap 11 for this purpose. This ball and socket joint protective cap 11 has three hollow cylindrical sections 12, 13 and 14 in the exemplary embodiment being shown. The hollow cylindrical sections have different diameters, the hollow cylindrical section 12 with the largest diameter facing the joint housing 1 of the ball and socket joint. The hollow cylindrical section 13, which is adjacent to the section 12, has a slightly larger diameter than the conical receiving section 8 of the pivot pin 3, which said receiving section is located inside and is covered by the section 12 of the ball and socket joint protective cap 11. A transition area 16 extending essentially at right angles to the axial longitudinal direction of the ball and socket joint protective cap 11 is arranged in the transition between the hollow cylindrical sections 12 and 13. This transition area creates a contact surface 17 on the inner side of the ball and socket joint protective cap 11, which said contact surface 17 comes into contact with a corresponding contact surface 18 of the sealing bellows 5 when the ball and socket joint protective cap 11 is attached to the joint housing 1 and displaces the sealing bellows 5 in the direction of the arrows P. i.e., in the direction of the joint housing 1 on the conical receiving section 8 of the pivot pin 3 because of the dimensioning of the lengths of the individual hollow cylindrical sections. Due to the displacement in the direction of the arrows P, the radial pretension is also increased at the contact surface with the pin-shaped area 7 and the sealing action is thus improved because of the deformation of the sealing bellows at its internal diameter that is in contact with the conical receiving section 8 as well as of the arched area 19 as a consequence of the axial pretension. A sealing gap, which protects the outer side of the sealing bellows 5 from contaminants, is created at the same time due to the contact between the contact surface 17 and the contact surface 18.
The ball and socket joint protective cap according to the present invention is also provided in this exemplary embodiment with a transition area 20 extending essentially at right angles to the axial longitudinal direction of the ball and socket joint protective cap 11 in the transition between the hollow cylindrical section 13 and the hollow cylindrical section 14. The transition area 20, which is thus shaped as a step, comes into contact with a recess 21 of the pivot pin 3, which is present between the conical receiving section 8 and the threaded section 9. The contact in the area of the recess 21 of the pivot pin 3 and the ball and socket joint protective cap 11 brings about an additional sealing gap, by which contaminants are prevented from penetrating into the cavity 22 between the hollow cylindrical section 13 and the conical receiving section 8 of the pivot pin 3. The prerequisite for contact with the recess 21 is that the diameter of the hollow cylindrical section 14 at the free end of the ball and socket joint protective cap be selected to be only slightly larger than the external diameter of the threaded section 9.
Furthermore, FIG. 2 shows that to fix the ball and socket joint protective cap 11 on the pin-shaped partial area 7 of the pivot pin 3, at least one radially inwardly projecting elastic tongue 24, which is designed as a tongue extending circularly along the entire inner contour, is arranged at the inner contour of the hollow cylindrical section 14 located at the free end of the ball and socket joint protective cap 11, which said free end faces away from the joint housing 3. Corresponding to FIG. 1, this tongue engages a thread of the threaded section 9 of the pivot pin 3, which said threaded section is enclosed by the hollow cylindrical section 14 in question and thus ensures the reliable fixation of the ball and socket joint protective cap 11 on the pin-shaped partial area 7 of the pivot pin 3, so that fixation of the ball and socket joint protective cap 111 at the joint housing 1 can be dispensed with.
An increase in the elasticity of the circular tongue 24 can be brought about in such a way that the elastic tongue 24, which is designed as an inwardly projecting circular tongue, has a plurality of slots 26 distributed over the entire circumference of the tongue, as this is clearly apparent from FIG. 3.
Corresponding to the views in FIGS. 2 and 3, pulling off of the ball and socket joint protective cap from the pin-shaped partial area 7 of the ball and socket joint is facilitated in such a way that at least one radially outwardly projecting step 25, which is designed as a circular slot in the exemplary embodiment, is arranged at the outer edge of the hollow cylindrical section 14 located at the free end of the ball and socket joint protective cap 11, which said free end faces away from the joint housing 1.
While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

Claims

1. A ball and socket joint protective cap for covering a pin-shaped partial area of a completely mounted ball and socket joint provided with a joint housing and a pivot pin accommodated pivotably therein, the protective cap comprising:

a first cap section;

a second cap section, said first and second cap section being attachable to the pivot pin of the ball and socket joint, said first cap section having a different geometry from said second cap section, said first cap section being adjacent to said second cap section with respect to an axial longitudinal direction of the ball and socket joint protective cap with a section having a larger outer dimension being arranged at an end of the ball and socket joint protective cap, which end faces the joint housing; and

a transition area extending essentially at right angles to the axial longitudinal direction of the ball and socket joint protective cap, said transition area being arranged at a transition of said first section and said second sections.

2. A ball and socket joint protective cap in accordance with claim 1, wherein the adjacent first section and second section are hollow and cylindrical, wherein a dimension of a diameter of a smaller hollow cylindrical section of the ball and socket joint protective cap is only slightly larger than the dimension of the covered, pin-shaped partial section of the ball and socket joint.

3. A ball and socket joint protective cap in accordance with claim 1, further comprising another section, said first, second and another section each being a hollow cylindrical section of different relative diameters and together extending over an overall axial length of the ball and socket joint protective cap, wherein the diameter values of the individual sections decrease from the end facing the joint housing to the opposite free end of the ball and socket joint protective cap, said transition area extending essentially at right angles to the axial longitudinal direction of the ball and socket joint protective cap and arranged at the transition of the hollow cylindrical sections, wherein the dimension of the diameter of the respective smaller hollow cylindrical section of the ball and socket joint protective cap is only slightly larger than the dimension of the section of the pin-shaped partial area of the ball and socket joint, said section of the pin-shaped partial area of the ball and socket joint being covered by one or more of the hollow cylindrical sections.

4. A ball and socket joint protective cap in accordance with claim 3, further comprising at least one radially inwardly projecting elastic tongue arranged at an inner contour of a hollow cylindrical section located at the free end of the ball and socket joint protective cap, said free end facing away from the joint housing.

5. A ball and socket joint protective cap in accordance with claim 4, wherein said radially inwardly projecting elastic tongue is arranged at an inner contour of the hollow cylindrical section and is designed as a tongue extending circularly along the entire inner contour.

6. A ball and socket joint protective cap in accordance with claim 5, wherein said radially inwardly projecting elastic tongue is arranged at an inner contour of the hollow cylindrical section and has a plurality of slots distributed over an entire circumference of said tongue.

7. A ball and socket joint protective cap in accordance with claim 1, wherein at least one radially outwardly projecting step is arranged at an outer edge of the hollow cylindrical section and is located at a free end of the ball and socket joint protective cap, said free end facing away from the joint housing.

8. A ball and socket joint protective cap in accordance with claim 7, wherein a radially outwardly projecting step is designed as a circular step.

9. A ball and socket joint protective cap and ball and socket joint assembly, comprising:

a ball and socket joint with a joint housing and a pivot pin accommodated pivotably therein, said ball and socket joint having an axial length;

a protective cap with a first cap section and a second cap section, said first and second cap sections being attached to said ball and socket joint, said first cap section having a different geometry and being larger than said second cap section, said first cap section being adjacent to said second cap section with respect to an axial longitudinal direction of the ball and socket joint, said first cap section having a larger outer dimension and being arranged at an end of the ball and socket joint protective cap, which end faces said joint housing and a transition area extending essentially at right angles to the axial longitudinal direction of the ball and socket joint protective cap, said transition area being arranged at a transition of said first section and said second section.

10. An assembly in accordance with claim 9, wherein said adjacent first section and second section are hollow and cylindrical, wherein a dimension of a diameter of said second section is only slightly larger than the dimension of the covered, pin-shaped partial section of the ball and socket joint.

11. An assembly in accordance with claim 9, further comprising another section, said first, second and another section each being a hollow cylindrical section of different relative diameters and together extending over an overall axial length of the ball and socket joint protective cap, wherein the diameter values of the individual sections decrease from the end facing the joint housing to the opposite free end of the ball and socket joint protective cap.

12. An assembly in accordance with claim 9, wherein a dimension of a diameter of a smaller hollow cylindrical section of said ball and socket joint protective cap is only slightly larger than the dimension of the section of the pin-shaped partial area of the ball and socket joint, said section of the pin-shaped partial area of the ball and socket joint being covered by one or more of the hollow cylindrical sections.

13. A assembly in accordance with claim 11, further comprising at least one radially inwardly projecting elastic tongue arranged at an inner contour of one of said hollow cylindrical sections located at the free end of the ball and socket joint protective cap, said free end facing away from the joint housing.

14. A assembly in accordance with claim 13, wherein said radially inwardly projecting elastic tongue is arranged at an inner contour of the hollow cylindrical section and is designed as a tongue extending circularly along the entire inner contour.

15. A assembly in accordance with claim 14, wherein said radially inwardly projecting elastic tongue is arranged at an inner contour of the hollow cylindrical section and has a plurality of slots distributed over an entire circumference of said tongue.

16. A assembly in accordance with claim 9, wherein at least one radially outwardly projecting step is arranged at an outer edge of the hollow cylindrical section and is located at a free end of the ball and socket joint protective cap, said free end facing away from the joint housing.

17. A assembly in accordance with claim 16, wherein a radially outwardly projecting step is a circular step.