Method for connecting a spindle to a spindle holding element, longitudinal adjustment device for a vehicle seat

Abstract

Method for connecting a spindle (12) to a spindle holding element (14) for producing a longitudinal adjustment device (1) for a vehicle seat (16), wherein the spindle (12) has a thread (120) for producing a threaded engagement with a spindle nut of an adjustment mechanism (15) of the longitudinal adjustment device (1), characterized in that in the method the spindle (12) extending along a longitudinal axis (L) is metallurgically joined to a connecting section (142) of the spindle holding element (14), which forms a flat bearing surface (147) on which the spindle (12) is placed along a single line directed parallel to the longitudinal axis (L) of the spindle (12), using a resistance welding process on a section on which the thread (120) extends, by applying a first welding electrode (30) to the spindle (12) and a second welding electrode (31) to the spindle holding element (14).to conduct an electric welding current (I) between the first welding electrode (30) and the second welding electrode (31) through the spindle (12) and the spindle holding element (14) in order to produce the weld joint (2) at the transition between the spindle (12) and the support surface (147) via a current density acting on the line.

Claims

[1] Method for connecting a spindle (12) to a spindle holding element (14) for producing a longitudinal adjustment device (1) for a vehicle seat (16), wherein the spindle (12) has a thread (120) for producing a threaded engagement with a spindle nut of an adjustment gear (15) of the longitudinal adjustment device (1), characterized byin that in the method the spindle (12) extending along a longitudinal axis (L) is materially connected to a connecting section (142) of the spindle holding element (14), which forms a flat support surface (147) on which the spindle (12) is placed along a single line directed parallel to the longitudinal axis (L) of the spindle (12), using a resistance welding process at a section on which the thread (120) extends, by applying a first welding electrode (30) to the spindle (12) and a second welding electrode (31) to the spindle holding element (14) in order to conduct an electrical welding current (I) between the first welding electrode (30) and the second welding electrode (31) through the spindle (12) and the spindle holding element (14) in order to produce the welded connection (2) at the transition between the spindle (12) and the support surface (147) via a current density acting on the line. [2] Method according to claim 1, characterized by that the first welding electrode (30) is placed on a side of the spindle (12) facing away from the spindle holding element (14). [3] Method according to claim 1 or 2, characterized by that the first welding electrode (30) has a semicircular curved contact surface (300) for contact with the spindle (12), the shape of which is adapted to the shape of the spindle (12) in such a way that a flat contact can be obtained between the first welding electrode (30) and the spindle (12). [4] Method according to one of claims 1 to 3, characterized by that the second welding electrode (31) is placed on a side of the spindle holding element (14) facing away from the spindle (12). [5] Method according to one of claims 1 to 4, characterized by that the second welding electrode (31) is placed on a side of the connecting section (142) facing away from the spindle (12). [6] Method according to one of claims 1 to 4, characterized by that the second welding electrode (31) is placed on an underside (146) of a fastening section (140) of the spindle holding element (14) facing away from the spindle (12) and connected to the contact section (142), wherein the fastening section (140) is designed to fasten the spindle holding element (14) to a guide rail (10, 11) of the longitudinal adjustment device (1). [7] Method according to one of the preceding claims, characterized by that a distance (H1, H2) between the first welding electrode (30) and the second welding electrode (31) is monitored and the welding current (I) is switched off when a predetermined distance value is reached. [8] Method according to one of the preceding claims, characterized by that a welding current (I) for the resistance welding process is set to a value in a range between 5 and 25 kA. [9] Method according to one of the preceding claims, characterized by that a contact force for pressing the spindle (12) and the spindle holding element (14) together is set to a value in a range between 100 daN and 1000 daN. [10] Method according to one of the preceding claims, characterized by that a current time for the resistance welding process is set to a value in a range between 50 ms and 500 ms. [11] Method according to one of the preceding claims, characterized by that the connecting section (142) has a material thickness (M) between 2 mm and 10 mm. [12] Longitudinal adjustment device (1) for a vehicle seat (16), with - a guide rail (10), - a spindle (12) to be connected to the guide rail (10) and extending along a longitudinal axis (L), which spindle has a thread (120) for establishing a threaded engagement with a spindle nut of an adjusting gear (15) of the longitudinal adjustment device (1), and - a spindle holding element (14) for connecting the spindle (12) to the guide rail (10), wherein the spindle holding element (14) has a connecting section (142) which forms a flat support surface (147) and to which the spindle (12) is integrally connected, characterized byin that the spindle (12) is connected to the connecting section (142) via a welded connection (2) produced using a resistance welding process and by placing the spindle (12) on the support surface (147) along a single line directed parallel to the longitudinal axis (L) of the spindle (12), at a section on which the thread (120) extends, wherein in the resistance welding process a first welding electrode (30) is applied to the spindle (12) and a second welding electrode (31) is applied to the spindle holding element (14) in order to conduct an electrical welding current (I) between the first welding electrode (30) and the second welding electrode (31) through the spindle (12) and the spindle holding element (14), in order in this way to produce the welded connection (2) at the transition between the spindle (12) and the support surface (147) via a current density acting on the line. [13] Longitudinal adjustment device (1) according to claim 12, characterized bythat the spindle (12) has a diameter (D) between 5 mm and 12 mm.

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