Method for connecting a screw rod holding element to a guide rail

Abstract

In a method for connecting a screw spindle holding element (14) to a guide rail (10) to produce a longitudinal adjustment device (1) for a vehicle seat (16), the screw spindle holding element (14) for fastening a screw spindle (12) is materially bonded to a wall section of the guide rail (10) in the case of use of an electric resistance welding process, in particular an electric resistance projection welding process. In this way, a method for connecting a screw spindle holding element to a guide rail is provided, which enables a fixed connection of the screw spindle to the guide rail with simple handling and monitoring of the production process.

Description

Technical Field

[0001] The present invention relates to a method for connecting a lead screw retaining element to a guide rail to manufacture a longitudinal adjustment device for a vehicle seat, and to a longitudinal adjustment device for a vehicle seat. Background Technology

[0002] In this method, the screw retaining element used to fasten the screw is locked to the wall section material of the guide rail.

[0003] The longitudinal adjustment device is used to adjust the longitudinal positioning of the vehicle seat in the vehicle. In the longitudinal adjustment device, the vehicle seat is arranged in a movable manner relative to the bottom of the vehicle, for example, via two pairs of guide rails on both sides of the vehicle seat, so that the longitudinal positioning of the vehicle seat can be adjusted by moving the upper rail of the guide rail pair relative to the lower rail of the guide rail pair.

[0004] Such longitudinal adjustment devices typically use a lead screw drive, in which, in one design, the lead screw is statically fixed on a matching guide rail and threadedly engaged with a lead screw nut of an adjustment transmission device connected to other guide rails. When the lead screw nut is driven, it twists relative to the lead screw and, under the action of the threaded engagement, adjusts longitudinally along the lead screw, thereby causing the guide rails to move relative to each other.

[0005] When connecting the lead screw to the matching guide rail, it is essential to ensure that the lead screw remains firmly attached to the guide rail even under high loads, especially in the event of a collision, and does not detach from the guide rail. Therefore, the connection between the lead screw and the matching guide rail is subject to high strength requirements.

[0006] Furthermore, the leadscrew should occupy a defined position relative to the mating guide rail, and in particular, maintain a defined height relative to the guide rail (along the Z direction), but also remain within defined longitudinal and lateral positioning (along the X and Y directions) to ensure quiet and smooth adjustment operation. For this purpose, it is necessary that the leadscrew occupy a defined position relative to the mating guide rail, despite possible tolerances.

[0007] In the longitudinal adjustment device known from DE 10 2004 001 593 B3, the lead screw is welded to the two ends of an associated fastening element in the form of a retaining bracket, and is thus fixedly placed on the fastening element.

[0008] In the longitudinal adjusting device known from WO 2016 / 150791 A1, the lead screw is connected to an associated guide rail at its end via a lead screw retainer. The lead screw retainer has two flanges, the lead screw is housed between the two flanges, and is connected to the lead screw by welding.

[0009] DE 10 2018 212 288 A1 discloses a method for connecting a lead screw to a lead screw retaining element to manufacture a longitudinal adjustment device for a vehicle seat, wherein the lead screw is connected to the lead screw retaining element material in a locking manner using a resistance welding process. Summary of the Invention

[0010] The objective of this invention is to provide a method for connecting a lead screw retaining element to a guide rail to manufacture a longitudinal adjustment device for a vehicle seat, and a longitudinal adjustment device for a vehicle seat, which enables the lead screw to be fixedly connected to the guide rail by one or more lead screw retaining elements in a simple, operable, and monitorable manufacturing process.

[0011] This task is solved by a subject matter that has the characteristics of the present invention.

[0012] Therefore, when using resistance welding, the lead screw retaining element is connected to the wall section of the guide rail.

[0013] The lead screw should be fixedly placed on the guide rail of the longitudinal adjustment device by means of a lead screw retaining element, so that the lead screw is reliably and load-bearingly connected to the guide rail. The connection between the lead screw and the guide rail is achieved by locking the lead screw retaining element to the wall section of the guide rail, especially the bottom material of the guide rail which is substantially U-shaped in cross-section, so that the lead screw retaining element is load-bearingly fastened to the wall section of the guide rail.

[0014] Resistance welding is used to establish a material-locking connection. Within the scope of resistance welding, welding current is conducted between the lead screw retainer and the guide rail so that a welded connection is established at the transition between the lead screw retainer and the guide rail by the current density acting there.

[0015] In principle, different resistance welding processes can be used. Therefore, for example, resistance spot welding can be used, where the current density is adjusted using approximately point-shaped welding electrodes. Alternatively, resistance projection welding can be used, where the current density required for welding is generated by the geometry of the components to be connected. The lead screw holding element and the guide rail are advantageously held together under force within the range of connection methods and welded together by welding current.

[0016] Resistance welding is advantageously achieved without the input of additional material. In resistance welding, the lead screw retaining element and the guide rail melt on their opposing sides, thereby establishing a material lock between the guide rail and the lead screw retaining element. Here, the lead screw retaining element is positioned relative to the guide rail, which enables simple and advantageous tolerance compensation for the defined position of the lead screw relative to the guide rail for which it is to be arranged.

[0017] Here, the position of the lead screw relative to the guide rail in the height direction (Z direction) can be adjusted by the adjustability of the lead screw holding element in resistance welding. Conversely, the position of the lead screw holding element relative to the guide rail in the longitudinal direction (X direction) and transverse direction (Y direction) can be adjusted by setting a predetermined position of the lead screw holding element relative to the guide rail in the welding tool.

[0018] In this method, during the resistance welding process, a first welding electrode is mounted on a lead screw holding element, while a second welding electrode is mounted on a guide rail. Through the first and second welding electrodes, the welding current between them is conducted through the lead screw holding element and the guide rail, thereby creating a high current density at the transition between the lead screw holding element and the guide rail, and providing a welded connection at the transition due to the welding current.

[0019] For example, the lead screw holding element and the guide rail are pressed against each other by a predetermined extrusion force through the first welding electrode and the second welding electrode, thereby establishing a welded connection under the force between the lead screw holding element and the guide rail.

[0020] The first welding electrode can, for example, be positioned on the side of the wall section of the lead screw retaining element away from the guide rail. Here, the first welding electrode can have a flat abutment surface for abutting against the edge of the wall section of the lead screw retaining element away from the guide rail. However, it is also conceivable and possible that the first welding electrode in the area of ​​its abutment surface is, for example, curved, or otherwise shaped differently from a straight extension, so that the welding electrode can be adapted to the shape of the lead screw retaining element, and thus achieve surface abutment of the first welding electrode on the lead screw retaining element.

[0021] In one design, the first welding electrode has a receiving opening in which a lead screw retaining element is received for introducing welding current. The receiving opening may be formed, for example, as a slit formed into the first welding electrode, such that the lead screw retaining element can be received in the receiving opening and abut against the surface of the first welding electrode.

[0022] The first welding electrode can be designed to abut against the lead screw retaining element on one or both sides. In particular, in an advantageous design, the welding electrode can abut against the following lower section of the lead screw retaining element, which extends transversely to the longitudinal axis of the lead screw to be retained by the retaining element. Abutment can be achieved on one side of the section. However, it may be advantageous to abut against the section on both sides so that welding current can be introduced into the lead screw retaining element from both sides. In particular, by having the welding electrode abut against the lead screw retaining element on both sides, a high-strength connection between the lead screw retaining element and the guide rail can be achieved, for example.

[0023] In one design, a first welding electrode has a first electrode section and a second electrode section, with a lead screw holding element arranged between them to introduce welding current. The first electrode section can abut against a first side of the lead screw holding element, while the second electrode section can abut against a second side of the lead screw holding element opposite to the first side. Therefore, the electrode sections allow welding current to be introduced into the lead screw holding element from both sides, particularly on the opposing sides of the transversely extending transversely to the longitudinal axis of the lead screw.

[0024] In one design, a clamping device can clamp the electrode sections together, thereby placing them in close contact with a lead screw holding element housed between the electrode sections. The clamping device may, for example, have a clamping bolt whose rod end engages with an opening in the lead screw holding element (the opening itself is used to receive the lead screw), thus positioning the lead screw holding element relative to the first welding electrode. The electrode sections can be clamped together by the clamping bolt, thereby placing them in close contact with the opposite side of the lead screw holding element to facilitate the introduction of welding current.

[0025] In the design of the method, the second welding electrode can, for example, be positioned on the side of the wall section of the guide rail away from the lead screw holding element. It is conceivable to position the second welding electrode on the rear side of the wall section, i.e., a portion below the side of the wall section away from the lead screw holding element, which corresponds to the axial portion of the lead screw holding element on the wall section, thereby positioning the second welding electrode opposite to the lead screw holding element. This creates a relatively short current path through the wall section. Alternatively, it is also conceivable to position the second welding electrode on the guide rail axially offset relative to the lead screw holding element.

[0026] In one design, the lead screw retaining element has a face section with end edges formed thereon. For connection to a guide rail, the lead screw retaining element is mounted edge-to-edge onto a wall section of the guide rail, and is thus locked to the guide rail wall section material via the end edges using a resistance welding process.

[0027] For this purpose, the lead screw retaining element can be formed, for example, as a stamped part with a plate shape, such that the lead screw retaining element extends substantially along a flat plane in the face section. Connection to the wall section of the guide rail is achieved by placing the end edges formed on the face section against each other onto the wall section of the guide rail.

[0028] In one design, the lead screw retaining element extends transversely to the longitudinal axis of the lead screw and is mounted on the wall section of the guide rail, such that when the lead screw is connected to the lead screw retaining element, the lead screw nut extends longitudinally along the guide rail, and the longitudinal axis of the lead screw is thus oriented parallel to the guide rail.

[0029] In one design, particularly when using resistance projection welding, the lead screw retaining element has at least one protruding section on its end edge, which, during placement, abuts against the wall section to establish a welded connection in the area of ​​the protruding section. In the resistance projection welding process, the lead screw retaining element is melted, particularly in the area of ​​the protruding section, thereby forming a material lock through the protruding section.

[0030] Advantageously, the lead screw retaining element has a plurality of protruding sections, which are separated from each other in pairs by recessed sections formed between them, and are arranged adjacent to each other, for example, in a transverse direction to the longitudinal axis. The protruding sections protrude from the face sections in the direction of the wall sections and are used to abut against the wall sections. During resistance welding, a material-locking connection is established in the area of ​​the protruding sections.

[0031] By using one or more protruding sections formed on the end edges of the face section of the lead screw retaining element, the advantage of adjustable configuration in resistance welding is obtained. Therefore, by melting in the region of the protruding section, the lead screw retaining element can be positioned relative to the wall section, allowing adjustment of the defined height of the lead screw retaining element for connecting the lead screw to the guide rail.

[0032] In one design, when establishing a connection between the lead screw retaining element and the guide rail, the nominal height of the opening in the lead screw retaining element relative to the wall section of the guide rail is adjusted. This opening is configured to secure the lead screw to the lead screw retaining element. The nominal height can be adjusted when the lead screw retaining element is positioned relative to the wall section of the guide rail, thereby compensating for tolerances in the shape of the lead screw retaining element and the wall section, particularly in the protruding areas, without affecting the position of the lead screw retaining element relative to the guide rail.

[0033] To adjust the nominal height of the opening, in one design, the distance between the welding electrodes during welding can be monitored as a shut-off criterion. The distance between the welding electrodes is related to the height position of the lead screw holding element relative to the guide rail. By monitoring the distance between the first and second welding electrodes, the lead screw holding element can be brought to a defined height position relative to the guide rail, so that the lead screw, after being secured to the lead screw holding element, occupies a defined height position relative to the guide rail.

[0034] Within the scope of process control, in resistance welding, for example, the distance between the welding electrodes can be compared with a predetermined distance value so that the welding current is cut off once the distance between the welding electrodes equals the predetermined distance value. If the predetermined distance value is reached, the welding process is thus terminated. Such control of the welding process enables precise tolerance compensation, especially for tolerance compensation of the height positioning of the lead screw holding element relative to the associated guide rail.

[0035] It is conceivable and possible to use such control in mass production, specifically in the connection between each lead screw retaining element and its associated guide rail, and thus in controlling the welding process during connection establishment. However, it is also conceivable and possible to use such control within the initial calibration range to determine the welding duration subsequently used in subsequent batch production. Subsequent batch production (within this range, with the lead screw retaining element connected to the associated guide rail) can then be achieved without process monitoring, i.e., without monitoring the distance between the welding electrodes.

[0036] Different parameters can be set for resistance welding to influence the quality, especially the strength, of the weld joint. For example, the welding current can be adjusted to a value between 5kA and 25kA, or, for example, between 10kA and 20kA. The pressure exerted by the welding electrodes to compress the lead screw holding element and the guide rail against each other can be set, for example, between 100 daN (ten Newtons) and 1000 daN, preferably between 400 daN and 900 daN. The current duration for applying the welding current in the resistance welding process can be set, for example, between 10 ms and 200 ms, preferably between 30 ms and 100 ms, for example, a value of 50 ms. All values ​​can be set in advance, for example, based on initial calibration and material inspection. However, it is also conceivable and possible to change the process parameters in a controlled manner during the welding process, for example, by relying on the control achieved through the distance between the welding electrodes to change the pressure and / or current duration.

[0037] By using short current times, especially those equal to or less than 50 ms, different materials can be interconnected in a load-bearing manner. For example, it is possible to lock very hard materials, such as the hard steel material of a lead screw retaining element, with softer materials, such as the softer material of a guide rail.

[0038] This task is also accomplished by a longitudinal adjustment device having a guide rail, a lead screw extending along the longitudinal axis to be connected to the guide rail, and a lead screw retaining element for connecting the lead screw to the guide rail. Here, the lead screw retaining element is connected to the wall section of the guide rail using a resistance welding process.

[0039] The advantages and favorable design schemes described above for this method are also similarly applicable to longitudinal adjustment devices, and therefore reference should be made to the above content in this regard. Attached Figure Description

[0040] The concept upon which this invention is based is described in detail below with the aid of embodiments shown in the accompanying drawings. Wherein: Figure 1 A schematic diagram of a longitudinal adjustment device for a vehicle seat is shown; Figure 2 A view is shown of a lead screw retaining element for securing the lead screw to a mating guide rail; Figure 3 A view of the lead screw retaining element on the wall section of the associated guide rail is shown; Figure 4 It shows according to Figure 3 End view of the arrangement; Figure 5 It shows according to Figure 3 A partially cut-out side view of the arrangement, showing the lead screw retaining element on the wall section of the guide rail; Figure 6 It shows according to Figure 5 A magnified view of a segment of the view; Figure 7 It shows according to Figure 6 A magnified view of a segment of the view; Figure 8 A view of a welding device for connecting a lead screw retaining element to a guide rail is shown. Figure 9 The perspective view shows the results based on Figure 8 A view of a welding apparatus that has no second welding electrode but has guide rails; Figure 10 A view of the clamping device of the welding apparatus is shown; Figure 11 A separate view is shown of the first welding electrode and the lead screw holding element housed thereon; Figure 12 A view of the clamping bolt of the clamping device is shown; and Figure 13 An enlarged view of the rod end of the clamping bolt is shown, which has a lead screw retaining element disposed thereon. Detailed Implementation

[0041] Figure 1 An embodiment of the longitudinal adjustment device 1 is shown, which is used for longitudinal adjustment along the vehicle's longitudinal direction X in a vehicle (in... Figure 1 (The vehicle seat 16 is shown only schematically.)

[0042] The longitudinal adjustment device 1 typically has two guide rail pairs, which are formed by guide rails 10 and 11 respectively. The upper rail 11 is attached to the vehicle seat 16, and the lower rail 10 is attached to the bottom of the vehicle. By adjusting the longitudinal position of the guide rails 10 and 11 relative to each other, the longitudinal positioning of the vehicle seat 16 in the vehicle can be adjusted.

[0043] The adjustment between guide rails 10 and 11 is achieved electrically via a lead screw drive. In the illustrated embodiment, the lead screw drive for each guide rail pair has a lead screw 12 fixedly placed on the lower rail 10 and an adjustment transmission 15 fastened to the upper rail 11. The lead screw 12 is held stationary and thus anti-rotationally on the lower rail 10 by lead screw holding elements 13 and 14, and has an external thread 120 through which the lead screw 12 is threadedly engaged with the lead screw nut of the adjustment transmission 15. This allows the lead screw nut to rotate relative to the lead screw 12 via electric drive, and thus the lead screw nut rolls on the lead screw 12 through the threaded engagement. This causes the adjustment transmission 15 to adjust longitudinally relative to the lead screw 12 along the longitudinal axis L (along which the lead screw 12 extends), and thus the upper rail 11 moves relative to the lower rail 10 along the longitudinal axis L.

[0044] In the illustrated embodiment, the lead screw 12 is fixedly connected to the lower rail 10 via lead screw retaining elements 13 and 14, and is thus fixedly placed on the bottom 100 of the lower rail 10 via lead screw retaining elements 13 and 14.

[0045] When the lead screw 12 is screwed into and thus connected to the lead screw retaining element 13, for example, the lead screw 12 is welded to another lead screw retaining element 14, so that the lead screw 12 is fixedly positioned relative to the guide rail 10 against relative rotation.

[0046] Figure 2 An embodiment of the lead screw retaining element 14 is shown, which is plate-shaped, for example constructed as a stamped part, and made of, for example, steel. The lead screw retaining element 14 has a face section 140 that extends transversely to the longitudinal axis L of the lead screw 12 when the longitudinal adjustment device 1 is installed, and as shown... Figures 3 to 7 As shown, it is connected to the wall section (in the form of the bottom 100 of the guide rail 10) so that the lead screw retaining element 14 protrudes from the bottom 100 and is loaded and connected to the bottom 100.

[0047] The face section 140 forms an opening 141 into which the lead screw 12 is inserted for fastening to the lead screw retaining element 14. The lead screw 12 can be fastened to the opening 141, for example, by welding, thereby fixing the lead screw 12 relative to the lead screw retaining element 14 in a fixed position against relative rotation in the installed position. Alternatively, a threaded connection between the lead screw 12 and the lead screw retaining element 14 can also be established through the opening 141.

[0048] The face section 140 is defined by end edge 142, and the lead screw retaining element 14 is mounted on the bottom 100 along this end edge for connection with the guide rail 10, so as to establish a welded connection 2 between the lead screw retaining element 14 and the bottom 100 of the guide rail 10. The connection between the lead screw retaining element 14 and the bottom 100 is achieved here using a resistance welding process, especially resistance projection welding, to establish a welded connection 2 within the range of resistance projection welding, and thus provide a mating connection between the lead screw retaining element 14 and the guide rail 10.

[0049] Protruding sections 143 are formed on the end edge 142 of the lead screw retaining element 14. These protruding sections are regularly spaced apart from each other in a transverse direction Y extending transversely to the longitudinal axis L, and are separated from each other in pairs by recessed sections 144 located between them. The protruding sections 143 protrude toward the bottom 100 relative to the recessed sections 144, so that when the lead screw retaining element 14 is placed on the bottom 100, the protruding sections 143 abut against the bottom 100 to establish a connection between the lead screw retaining element 14 and the guide rail 10.

[0050] The welded connection 2 between the lead screw retaining element 14 and the bottom 100 of the guide rail 10 is used. Figures 8 to 13 In the case of the welding apparatus 3 shown, it is manufactured by resistance welding. Within the range of resistance welding, the welding current is conducted via welding electrodes 30, 31 through the lead screw holding element 14 and the bottom 100, for example in... Figure 8 As shown in the figure, the first welding electrode 30 is attached to the lead screw holding element 14, while the second welding electrode 31 is attached to the rear side of the bottom 100 of the guide rail 10, so as to conduct welding current between the welding electrodes 30 and 31 and thus between the lead screw holding element 14 and the bottom 100 to establish a welded connection 2.

[0051] If welding current is conducted through the welding electrodes 30, 31 through the lead screw holding element 14 and the bottom 100 to establish a welded connection 2, then at the transition between the lead screw holding element 14 and the bottom 100, a large current density is formed in the region of the protruding section 143 (where the lead screw holding element 14 rests against the bottom 100), causing the protruding section 143 of the lead screw holding element 14 and the bottom 100 to melt in the transition region, and thus establishing a material-locked connection between the lead screw holding element 14 and the bottom 100.

[0052] Applying a compressive force to the lead screw retaining element 14 and the bottom 100 by welding electrodes 30 and 31 causes the lead screw retaining element 14 to press against the bottom 100, resulting in the lead screw retaining element 14 and the bottom 100 being positioned on each other during welding. This allows for tolerance compensation and precise adjustment of the height positioning of the lead screw retaining element 14 relative to the bottom 100 and, consequently, relative to the associated guide rail 10.

[0053] Welding electrodes 30 and 31 are components of welding apparatus 3, which has a control device 32 for controlling the welding process. In particular, the welding current passing through welding electrodes 30 and 31 is controlled via the control device 32, and the pressure F applied to the lead screw holding element 14 and the bottom 100 via welding electrodes 30 and 31 is also adjusted.

[0054] The welding current can be adjusted to a value between 5kA and 25kA, preferably between 10kA and 20kA, for example, between 13kA and 18kA, via the control device 32. The extrusion pressure can be adjusted, for example, to a value between 100daN and 1000daN, preferably between 400daN and 900daN, for example, between 500daN and 800daN. Furthermore, the holding time of the extrusion pressure and the current duration of the welding current I can be adjusted and controlled via the control device 32.

[0055] Welding current is fed through welding electrodes 30 and 31, causing the welding current to flow through the lead screw holding element 14 and the bottom 100, and establishing a current density at the transition between the lead screw holding element 14 and the bottom 100 that locally melts the lead screw holding element 14 and the bottom 100. To achieve favorable current feeding, the first welding electrode 30 is adjusted to achieve planar contact on both sides between the first welding electrode 30 and the planar segment 140 of the lead screw holding element 14. In contrast, the second welding electrode 31 may, for example, be constructed flat to rest against the bottom 100 on the rear side of the lead screw holding element 14.

[0056] exist Figures 8 to 13 In the welding apparatus 3 shown, the first welding electrode 30 has a slit-shaped receiving opening 300 in which the lead screw retaining element 14 for establishing the weld connection 2 is received. The receiving opening 300 is defined on both sides by electrode sections 301 and 302, which extend parallel to each other and are axially spaced apart along the longitudinal axis L (relative to the lead screw 12 to be conventionally connected to the lead screw retaining element 14), so that the lead screw retaining element 14 can be received between the electrode sections 301 and 302.

[0057] To establish weld connection 2, a lead screw retaining element 14 is arranged in the receiving opening 300 of the first welding electrode 30 and fixed to the first welding electrode 30 by a clamping device 33. This is achieved in such a way that a clamping bolt 331, guided in the bearing housing 330, is positioned with its rod end 334 engaged with the opening 141 of the lead screw retaining element 14, thereby defining the height of the lead screw retaining element 14 relative to the welding electrode 30, and the lead screw retaining element is supported on the welding electrode 30 by the clamping bolt 331. The rod end 334 passes through the opening 303 in the electrode section 302 and is engaged with the lead screw retaining element 14 within the receiving opening 300, for example from... Figure 12 and Figure 13 and Figure 10 and Figure 11 This can be seen from the summary.

[0058] The clamping bolt 331 can be clamped by the clamping handle 332, thereby bringing the electrode sections 301 and 302 closer together, and the lead screw retaining element 14 is thus clamped between the electrode sections 301 and 302. Here, at the transition between the rod end 334 and the rod 333 axially adjacent to the rod end 334, the abutment section 335 is formed in the form of a stepped portion surrounding the periphery, and the clamping bolt 331 acts on the electrode section 302 through this abutment section, thereby clamping the electrode section 302 relative to the electrode section 301.

[0059] Therefore, by means of electrode sections 301 and 302, the first welding electrode 30 can be placed on opposite sides of the face section 140 of the lead screw holding element 14, thereby allowing welding current to be introduced into the face section 140 and then into the lead screw holding element 14 from both sides. In this way, a high-strength welded connection can be established between the lead screw holding element 14 and the bottom 100 of the guide rail 10, which can withstand, in particular, the axial tension F acting along the lead screw 12 during the operation of the longitudinal adjustment device 1 (see...). Figure 7 Therefore, the lead screw 12 can be fixedly and load-bearingly connected to the guide rail 10 via the lead screw retaining element 14.

[0060] The clamping device 33 is arranged on the platform 336, which, for example, can be obtained from... Figure 10 As can be seen, the guide rail 10 can be accommodated in the support element 337, the first welding electrode 30, and the bearing seat 330 for connection with the lead screw retaining element 14, which can be seen, for example, from... Figure 9 It can be seen that a weld connection 2 can be established by placing the second welding electrode 31 on the rear side of the bottom 100 of the guide rail 10.

[0061] During the welding process, the protruding section 143 and the bottom 100 of the lead screw retaining element 14 are melted at the point of contact, so that the lead screw retaining element 14 and the bottom 100 are positioned on each other. After the welded connection is established, a material-locking connection is formed between the protruding section 143 of the lead screw retaining element 14 and the bottom 100.

[0062] Within the scope of the welding process, the lead screw holding element 14 and the bottom 100 are pressed against each other by the welding electrodes 30 and 31 under pressure, and welding current is also fed in. Here, the holding time of the pressure and the current duration of the welding current are usually different, but the pressure can be applied for a longer period of time compared to the welding current. After the welding current is turned off, the lead screw holding element 14 and the bottom 100 are thus pressed against each other with force for a certain period of time until the welded joint 2 hardens.

[0063] The welding process can be carried out in a controlled manner, for example, based on the distance between the welding electrodes 30, 31, so as to adjust the nominal height H of the lead screw holding element 14 to the bottom 100, for example, relative to the longitudinal axis (along which the lead screw 12 extends in the longitudinal adjustment device 1 after installation) centered through the opening 141. nom For example, the distance between the welding electrodes 30, 31 relative to the height position of the lead screw holding element 14 to the bottom 100 can be used as a shut-off criterion. If it is determined during welding that the distance between the welding electrodes 30, 31 reaches a predetermined distance value and the lead screw holding element 14 and the bottom 100 are thus positioned relative to each other at the desired height position, the welding current can be shut off and the welding process can be terminated.

[0064] This control can be implemented in mass production. However, it is also conceivable and possible to set process parameters within the scope of the initial calibration procedure based on this control, so that subsequent mass production can be performed without relying on the control of the distance between welding electrodes 30 and 31.

[0065] from Figure 4 As can be seen, for example, the nominal height H of the lead screw holding element 14 can be measured using measuring points MP1, MP2, and MP3. nom Nominal height H nom This is related to the center point of an opening 141 with a diameter D, wherein this center point is separated from the measuring point MP1 above the opening 141 by a height distance D1, and from the measuring points MP2 and MP3 below the opening 141 by a height distance D2, for example from... Figure 4 See.

[0066] The concept upon which this invention is based is not limited to the embodiments described above, but can also be implemented in completely different ways.

[0067] In particular, the lead screw retaining element, or two (or more) lead screw retaining elements, used to connect the lead screw to the associated guide rail can be connected to the associated guide rail by resistance welding of the type described.

[0068] The lead screw retaining element can also be designed differently from that shown and, for example, can have a block shape, etc.

[0069] List of reference numerals

[0070] 1. Longitudinal adjustment device

[0071] 10 Guide rails (bottom rail)

[0072] 100 bottom

[0073] 11. Guide rail (top rail)

[0074] 12 lead screws

[0075] 120 external thread

[0076] 13 Lead screw retaining element

[0077] 14 Lead screw retaining element

[0078] 140-section

[0079] 141 Opening

[0080] 142 End edge

[0081] 143 Protruding Section

[0082] 144 Recessed section

[0083] 15 Adjusting the transmission device

[0084] 16 Vehicle Seats

[0085] 2 Welded connection

[0086] 3 Welding equipment

[0087] 30, 31 Welding electrodes

[0088] 300 Accommodation opening

[0089] Electrode sections 301 and 302

[0090] 303 Opening

[0091] 32 Control device

[0092] 33 Clamping device

[0093] 330 bearing housing

[0094] 331 Clamping bolt

[0095] 332 Clamping handle

[0096] 333 strokes

[0097] 334 rod end

[0098] 335 Adjacent Section

[0099] 336 units

[0100] 337 Support element

[0101] D diameter

[0102] Distance between D1 and D2

[0103] F force

[0104] H nom Nominal height

[0105] L longitudinal axis

[0106] MP1~MP3 Measurement points.

Claims

1. A method for connecting a lead screw retaining element (14) to a guide rail (10) to manufacture a longitudinal adjustment device (1) for a vehicle seat (16), wherein, In the method described above, the lead screw retaining element (14) for fastening the lead screw (12) is locked to the wall section material of the guide rail (10). Its features are, When using resistance welding, the lead screw retaining element (14) is connected to the wall section of the guide rail (10). In the resistance welding process, a first welding electrode (30) is placed on the lead screw holding element (14), and a second welding electrode (31) is placed on the guide rail (10) so that welding current can be conducted between the first welding electrode (30) and the second welding electrode (31). The first welding electrode (30) has a first electrode section (301) and a second electrode section (302). To introduce welding current, the lead screw holding element (14) is arranged between the first electrode section and the second electrode section, such that the first electrode section (301) is in contact with a first side of the lead screw holding element (14), while the second electrode section (302) is in contact with a second side of the lead screw holding element (14) opposite to the first side. The first electrode section (301) and the second electrode section (302) are clamped together relative to each other by the clamping device (33) for abutting against the lead screw holding element (14).

2. The method according to claim 1, characterized in that, The first welding electrode (30) is placed on the side of the wall section of the lead screw retaining element (14) opposite to the guide rail (10).

3. The method according to claim 1, characterized in that, The first welding electrode (30) has a receiving opening (300) in which the lead screw holding element (14) is received for introducing welding current.

4. The method according to claim 1, characterized in that, The second welding electrode (31) is placed on the side of the wall section of the guide rail (10) away from the lead screw holding element (14).

5. The method according to claim 1, characterized in that, The lead screw retaining element (14) has a face section (140) having an end edge (142) arranged on the face section, wherein the lead screw retaining element (14) is mounted to the wall section of the guide rail (10) with the end edge (142) in order to be connected.

6. The method according to claim 5, characterized in that, The lead screw retaining element (14) has at least one protruding section (143) formed on the end edge (142) and through which a welded connection (2) is established between the lead screw retaining element (14) and the wall section of the guide rail (10).

7. The method according to claim 6, characterized in that, The lead screw retaining element (14) has a plurality of protruding sections (143) formed on the end edge (142) and through which a welded connection (2) is established between the lead screw retaining element (14) and the wall section of the guide rail (10).

8. The method according to claim 1, characterized in that, During connection, the nominal height (H) of the opening of the lead screw retaining element (14) configured to fasten the lead screw (12) onto the lead screw retaining element (14) relative to the wall section of the guide rail (10) is adjusted. nom ).

9. The method according to claim 1, characterized in that, Set the current-time setting for the resistance welding process to a value between 10ms and 200ms.

10. The method according to claim 1, characterized in that, Set the current-time setting for the resistance welding process to a value between 30ms and 100ms.

11. A longitudinal adjustment device (1) for a vehicle seat (16), the longitudinal adjustment device having a guide rail (10), a lead screw (12) extending along a longitudinal axis (L) to be connected to the guide rail (10), and a lead screw retaining element (14) for connecting the lead screw (12) to the guide rail (10). Its features are, The lead screw retaining element (14) is connected to the wall section of the guide rail (10) using a resistance welding process. In the resistance welding process, a first welding electrode (30) is placed on the lead screw holding element (14), and a second welding electrode (31) is placed on the guide rail (10) so that welding current can be conducted between the first welding electrode (30) and the second welding electrode (31). The first welding electrode (30) has a first electrode section (301) and a second electrode section (302). To introduce welding current, the lead screw holding element (14) is arranged between the first electrode section and the second electrode section, such that the first electrode section (301) is in contact with a first side of the lead screw holding element (14), while the second electrode section (302) is in contact with a second side of the lead screw holding element (14) opposite to the first side. The first electrode section (301) and the second electrode section (302) are clamped together relative to each other by the clamping device (33) for abutting against the lead screw holding element (14).

12. The longitudinal adjustment device (1) according to claim 11, characterized in that, The lead screw retaining element (14) has a face section (140) having an end edge (142) arranged on the face section, wherein the lead screw retaining element (14) is grounded to the wall section of the guide rail (10) with the end edge (142) facing each other.

13. The longitudinal adjustment device (1) according to claim 12, characterized in that, The lead screw retaining element (14) has a plurality of protruding sections (143) formed on the end edge and the protruding sections establish a welded connection (2) between the lead screw retaining element (14) and the wall section of the guide rail (10).

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