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Claims
1. Radial ball joint (1, 50, 70) for a vehicle, the radial ball joint (1, 50, 70) comprising a housing (2, 51) for holding a joint ball (11) of a ball stud (6) in such manner that it can rotate and pivot, wherein between an inside wall (10) of the housing (2, 51) and the joint ball (11) there is arranged an upper bearing shell (7) made of steel sheet which is in contact over a contact zone (21) against the joint ball (11) in order to provide a circumferential slide bearing for the joint ball (11) between its equator (12) and its upper pole (13), characterized in that the upper bearing shell (7) is in the form of an annular, circumferentially closed drawn component and has in the contact zone (21) with the joint ball (11) a plurality of lubrication grooves (14), which pass though a wall (20) of the upper bearing shell (7) in the manner of an embossment.
2. Radial ball joint (1, 50, 70) according to Claim 1, characterized in that the plurality of lubrication grooves (14) passing through the wall (20) of the upper bearing shell (7) protrude as bulges (22) on the surface region of the upper bearing shell (7) that faces away from the contact zone (21) with the joint ball (11).
3. Radial ball joint (1, 50, 70) according to Claims 1 or 2, characterized in that the lubrication grooves (14) extend in a plane passing through the central axis (27) of the ball stud (6).
4. Radial ball joint (1, 50, 70) according to any of Claims 1 to 3, characterized in that the upper bearing shell (7) is made of case-hardened steel and its surface is case-hardened all over.
5. Radial ball joint (1, 50, 70) according to any of the preceding claims, characterized in that an end face (23) of the upper bearing shell (7) facing toward the upper pole (13) of the joint ball (11), together with a corresponding stop surface (24) of a cover (4, 53) that closes off the housing (2, 51) on one side, form an end stop for a movement of the joint ball (11) in the axial direction (9).

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6. Radial ball joint (1, 50, 70) according to any of the preceding claims, characterized in that the upper bearing shell (7) is arranged radially a distance away from the inside wall (10) of the housing (2, 51)
7. Radial ball joint (1, 50, 70) according to any of the preceding claims, characterized in that between the upper bearing shell (7), the inside wall (10) of the housing (2, 51) and the cover (4, 53) there is arranged a round sealing ring (8) which is in contact all round with each of them, and by means of the round sealing ring (8) the upper bearing shell (7) is braced in the axial direction (9) against the joint ball (11).
8. Radial ball joint (1, 50, 70) according to Claim 7, characterized in that the bulges (22) act to impede rotation and prevent twisting of the upper bearing shell (7) relative to the round sealing ring (8), at least to a large extent.
9. Radial ball joint (1, 50, 70) according to any of the preceding claims, characterized in that between the inside wall (10) of the housing (2) and the joint ball (11) there is arranged a lower bearing shell (16) made of steel sheet, which is in contact with the joint ball over contact zones (25, 26), in order to provide a circumferential slide bearing for the joint ball (11) essentially between its equator (12) and a stud (18) connected to the joint ball (11).

10. Radial ball joint (1, 50, 70) according to Claim 9, characterized in that the lower bearing shell (16) is in the form of an annular, circumferentially closed drawn component and has in the contact zone (26) with the joint ball a plurality of lubrication grooves (15) which extend in a plane passing through the central axis (27) of the ball stud (6).
11. Radial ball joint (1, 50, 70) according to Claims 9 or 10, characterized in that in the contact zone (25) with the inside wall (10) of the housing (2), the lower bearing shell (16) is in the form of a circumferentially continuous spherical outer surface, at least in part.
12. Radial ball joint (1, 50, 70) according to Claims 10 or 11, characterized in that the lubrication grooves (15) are formed without machining, in the manner of an embossment in a wall (28) of the lower bearing shell (16).

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13. Radial ball joint (1, 50, 70) according to any of Claims 9 to 12, characterized in that the lower bearing shell (16) extends in the direction toward the upper pole (13) of the joint ball (11) to beyond the equator (12) of the joint ball (11).
14. Radial ball joint (1, 50) according to any of the preceding claims, characterized in that the radial ball joint (1, 50) has straight-through lubrication, with entry of the lubricant by way of a lubrication nipple (5, 52) and lubricant discharge by way of one or more outlet openings (19) in a sealing bellows (17) that seals the radial ball joint (1, 50) and extends between the housing (2, 51) and the ball stud (6).
15. Radial ball joint (1, 50) according to Claim 14, characterized in that the lubrication nipple (5) is arranged centrally in the cover (4), extending in the axial direction (9), or laterally in the housing (51), and in the case of the laterally arranged lubrication nipple (52) the lower bearing shell (55) has a cut-out in the area of at least one lubrication groove (57) to enable entry of the lubricant.
16. Radial ball joint (70) according to any of Claims 1 to 13, characterized in that the radial ball joint (70) is designed to be maintenance-free.