Linear drive, longitudinal adjustment device for a seat and motor vehicle

Abstract

The invention relates to a linear drive having at least one rack arranged along a longitudinal axis and having a plurality of teeth, a drive shaft arranged on a transverse axis transverse to the longitudinal axis, and at least two push elements each having at least one push tooth, wherein the at least two push elements are linearly movable on a stroke axis oriented transverse to the longitudinal axis and transverse to the drive shaft, the at least two push elements are drivingly coupled with the drive shaft such that the at least two push elements perform at least one cyclic stroke movement during a rotation of the drive shaft and extend into and out of the at least one rack to generate a pushing force on the longitudinal axis, and the at least two push elements extending into and out of the at least one rack are performed with a phase offset.

Description

TECHNICAL FIELD

[0001] The invention relates to a linear drive, a longitudinal adjustment device for a seat and a motor vehicle. BACKGROUND

[0002] Linear drives are known from the prior art in different design variants and are widely used as longitudinal adjustment devices for adjusting the position of a seat in a motor vehicle. The longitudinal adjustment device usually interacts with a lower rail fixed to the chassis and an upper rail arranged within the lower rail, wherein the upper rail can be moved electrically by the linear drive. In the prior art, the adjustment of the upper rail by the linear drive is usually carried out by means of a spindle which is arranged within the upper rail and is supported at its respective first and second end.

[0003] Such longitudinal adjustment devices are known, for example, from DE 36 40 197 A1, DE 42 08 948 C2, DE 196 42 655 C2, DE 198 15 283 A1, DE 10 2004 013 009 A1 and DE 10 2006 052 936 A1.

[0004] Due to the high requirements of the linear drive which must ensure the safety in the event of an accident in addition to the adjustment function in the longitudinal adjustment device, different structural forms of such linear drives are necessary which require different manufacturing methods and processes. It has been shown that a gapless linear movement requires a great deal of effort to achieve and the adaptation of the breaking load also requires a great deal of effort. It should also be mentioned that the longitudinal adjustment device should adjust the seat in the motor vehicle as noiselessly as possible in order to improve the comfort. SUMMARY

[0005] The invention is presented here.

[0006] The object of the invention is to present an improved linear drive which improves the linear drives known from the prior art in a purposeful manner. Furthermore, the linear drive should have a particularly compact structural form and enable a gapless linear movement as far as possible, while the breaking load is variable and adaptable. Furthermore, the linear drive should enable a high adjustment speed.

[0007] These objects are achieved by the linear drive, the longitudinal adjustment device and the motor vehicle of the invention.

[0008] The linear actuator according to the invention has at least one rack arranged along a longitudinal axis and having a plurality of teeth preferably of the same distribution. Furthermore, the linear actuator according to the invention has: a drive shaft arranged transversely to the longitudinal axis on a transverse axis; and at least two propulsion elements, each having at least one propulsion tooth, wherein the at least two propulsion elements are linearly movable on a stroke axis transversely to the longitudinal axis and oriented transversely to the drive shaft. The at least two propulsion elements are also driven coupled to the drive shaft such that the at least two propulsion elements perform at least one cyclic stroke movement during rotation of the drive shaft and extend and retract at least one rack to generate propulsion force on the longitudinal axis, wherein the extension and retraction of the at least two propulsion elements into and out of the at least one rack are phase-shifted.

[0009] Here and below, cyclic stroke motion is understood as the motion process of the corresponding propulsion element, wherein the propulsion element extends into the rack from the starting point once, and extends completely out of the rack once and returns to the starting point, and vice versa. The corresponding propulsion element can perform one or more complete cycles or loops during the rotation of the drive shaft, wherein the number of cycles or loops always corresponds to an integer.

[0010] When the corresponding propulsion element or at least one of its propulsion teeth extends into the rack, the teeth and at least one propulsion tooth effectively contact each other, thereby generating a propulsive force along the longitudinal axis. For this purpose, the corresponding propulsion tooth extends into the rack or the tooth gap between two teeth of the rack, wherein the propulsion tooth and the rack teeth effectively contact each other on a so-called friction surface, thereby generating the propulsive force. For this purpose, it is necessary that at least the teeth and / or the propulsion teeth have corresponding friction surfaces, which may be configured as wedge-shaped surfaces.

[0011] Furthermore, it should be noted that, in conjunction with the present invention, phase offset is understood as at least two propulsion elements extending into and out of the rack at different rotation angles of the drive shaft.

[0012] The present invention is based on the idea of ​​proposing a linear actuator whose drive shaft is arranged transversely to the longitudinal axis of the rack. This linear actuator is particularly advantageous for use in seat longitudinal adjustment devices because two linear actuators can operate in parallel with each other using a single actuator, without the need for an additional gearbox or transmission. Furthermore, the proposed linear actuator can have a particularly compact structure and can be configured without backlash and has a high breaking load.

[0013] Furthermore, it has proven particularly advantageous that the linear actuator has more than two propulsion elements, wherein, preferably, four, six, or eight propulsion elements are provided. It should also be noted that the number of propulsion elements need not be even, nor is there an upper limit to their number.

[0014] An advantageous design of the linear actuator according to the invention can be specified that the cyclic stroke motion of at least two propulsion elements is relative to the rotation of the drive shaft. The phase shift is at least More preferably at least or And preferably less than or equal to Preferably, the phase offset is less than Especially or

[0015] Advantageously, the mathematical reciprocal of the corresponding fraction of phase offset (1 / n) predetermines the number k of the propulsion elements to be set, i.e., k = (n / i), where the number i is the number of revolutions around the drive shaft. The number of cyclic strokes of the propulsion element. For example, when the phase offset between the propulsion elements should be... Furthermore, when each propulsion element performs a complete stroke, it is preferable to have at least two propulsion elements (n=4).

[0016] An improvement of the invention specifies that at least one propulsion tooth of one of the at least two propulsion elements is arranged offset relative to the drive shaft on the longitudinal axis compared to at least one propulsion tooth of the other of the at least two propulsion elements, and / or at least one tooth of at least one rack that can extend into and out of one of the at least two propulsion elements is arranged offset relative to at least one tooth of at least one rack that can extend into and out of the other of the at least two propulsion elements on the longitudinal axis. In other words, it is possible to achieve that the rack and / or propulsion elements have shapes adapted to the phase offset and the resulting propulsive force, so as to use, in particular, a large number of identical or structurally identical components, especially the propulsion elements or racks.

[0017] For example, in a preferred design, at least one rack and at least two propulsion elements can have helical teeth, wherein the teeth of the helical teeth extend with a helix angle α. The phase shift of the at least two propulsion elements entering and exiting the rack is achieved through the helical teeth. In this preferred design, the at least two propulsion elements can be designed to be identical or structurally identical, and can have helical teeth corresponding to the rack, thereby achieving phase shift on the one hand, and acoustic optimization from the surface contact between the propulsion elements and the rack on the other hand, through linear contact. Advantageously, the following relationship is derived for helical gears, where α is the helix angle of the helical teeth, y is the distance from the geometric center on the transverse axis between the at least two propulsion elements, k is the number of propulsion elements, and x is the distance between two teeth of the rack, wherein the following applies:

[0018]

[0019] Additionally, it is advantageous that the helical teeth of the propulsion element have a slightly different helix angle than the rack, wherein, preferably, the difference in helix angle is 1°≤Δα≤2°.

[0020] According to one design of the present invention, each of the at least two propulsion elements may also be provided with a rack, wherein the teeth of the respective rack have an offset in the longitudinal axis corresponding to a phase offset. The offset between the teeth of the respective racks can be adjusted during rotation of the drive shaft. When the drive tooth (i=1) is in a cyclic stroke motion, the following relationship is preferably obtained, where Δx is the offset, x is the distance between two teeth of the rack, and k is the number of propulsion elements:

[0021]

[0022] At least two propulsion elements can be identical, thereby increasing the number of identical parts.

[0023] In one embodiment of the invention, it is also possible to have at least one propulsion tooth of one of the at least two propulsion elements arranged offset relative to the drive shaft along the longitudinal axis compared to at least one propulsion tooth of the other of the at least two propulsion elements. In this case, due to the position of at least one propulsion tooth along the longitudinal axis, the propulsion elements are not identical components but have different shapes. The offset between the propulsion teeth of the respective propulsion elements can be adjusted during the rotation of the drive shaft. When the propulsion element (i=1) undergoes cyclic stroke motion, the following relationship is preferably derived, where Δx is the offset, x is the distance between two teeth of the rack, and k is the number of propulsion elements:

[0024]

[0025] It should be noted here that the propulsion teeth of the propulsion element, the teeth of the rack, can be arranged offsetly, and / or both the rack and the propulsion element can have helical teeth. Therefore, all combinations are possible.

[0026] An improvement of the invention specifies that at least two propulsion elements have more than one propulsion tooth. It may be advantageous, for example, that at least two propulsion elements have multiple propulsion teeth, such as two, three, four, or more, wherein the respective propulsion teeth do not necessarily have a complete tooth profile. By using multiple propulsion teeth on the respective propulsion elements, the breaking load can be increased through higher overlap of the linear actuators.

[0027] An improvement of the invention specifies that at least two propulsion elements are arranged transversely to the longitudinal axis and parallel to each other. Preferably, the at least two propulsion elements are arranged adjacent to each other with a gap as small as possible, wherein the gap ensures contactless movement between the at least two propulsion elements.

[0028] According to an advantageous improvement, at least two propulsion elements each have a groove, wherein coupling between the drive shaft and the propulsion element takes place within the groove. Preferably, the groove passes through at least one of the at least two propulsion elements, and more preferably, through both propulsion elements. In this preferred design, the groove extends completely through the propulsion element, wherein the groove can be configured as a through-hole or perforation, or as an outwardly opening slot. The groove preferably forms two side surfaces configured to establish sliding contact with the drive shaft. Preferably, the two side surfaces are arranged on two diametrically opposite sides. At least one propulsion tooth of the respective propulsion element can preferably be arranged parallel and spaced apart on the outer side opposite to the two side surfaces.

[0029] Another preferred embodiment of the invention specifies that the drive shaft includes a camshaft, and the camshaft is driven coupled to at least two propulsion elements. The camshaft interacts with the at least two propulsion elements and has a guide device by which coupling with the respective propulsion element can be achieved. In a preferred embodiment, the camshaft has a camshaft disk for each of the at least two propulsion elements, wherein the camshaft disk has a guide device that predetermines a cyclic stroke motion during rotation of the drive shaft of the respective propulsion element. The at least two camshaft disks are arranged parallel to each other on a transverse axis, and the deflection of the respective propulsion element is predetermined by the angular position of the respective camshaft disk.

[0030] Preferably, at least one of the side surfaces of the camshaft contact groove forms a drive coupling between the camshaft and at least one propulsion element.

[0031] An improved embodiment of the invention has proven advantageous in that at least two camshaft disks are arranged at an angle β offset about the longitudinal axis. Preferably, this angle is 0 < β < 360°. For example, in a design of a linear drive with four propulsion elements, this angle can be approximately 90°.

[0032] Another advantageous design of the invention specifies that the camshaft disk is configured asymmetrically about a longitudinal axis, wherein, more preferably, the camshaft disk is configured mirror-symmetrically about a plane on the longitudinal axis.

[0033] Furthermore, it has proven particularly advantageous that at least one camshaft disk is designed such that at least one actuating element is pressed into and out of the rack at a substantially constant speed as the camshaft rotates about the longitudinal axis at a constant angular velocity. In this context, the substantially constant speed of the at least one actuating element should be understood as an approximately constant speed between the two inflection points where the at least one actuating element is pressed into or out of the rack. Between the two inflection points, preferably greater than 80% of the stroke, preferably greater than 90% of the stroke, the speed should be within a tolerance of approximately ±10%, more preferably ±5%, of the average value. At the inflection points, the actuating element decelerates accordingly and then accelerates again. This motion can be described as zigzag in an XY diagram, where the stroke is resolved on the X-axis and the rotation angle is resolved on the Y-axis.

[0034] It has also proven advantageous that, according to an improved embodiment of the invention, the friction surfaces of the camshaft disk are configured with a distance from the longitudinal axis in the rotational direction, and this distance increases approximately linearly in the rotational direction in at least a first segment and decreases linearly in the rotational direction in at least a second segment. Thus, the friction surfaces extend approximately in a helical manner, wherein the friction surfaces are configured such that the distance between the two diametrical sides is approximately constant, or approximately corresponds to the width of the groove of the corresponding actuating element. In this design, the camshaft disk has a heart-shaped form, wherein the center point of the surface moves in a plane located on the longitudinal axis during rotation about the longitudinal axis.

[0035] It has also proven advantageous that at least one first segment and at least one second segment are connected by at least one rounded transition. Particularly preferred is that, in the transition, the distance between the two diametrical sides of the friction surface is slightly less than the width of the groove, thereby preventing the camshaft disc from getting stuck or tilting in the groove. Particularly preferred is that the transition is configured as a transition radius, wherein the transition radius approximately corresponds to the width of the groove, preferably having a tolerance of ±10%.

[0036] In an improved embodiment of the invention, the first segment and / or the second segment may extend in a semicircle. By designing the camshaft disc in this way, the propulsion element is fully pressed into the rack once and then pressed out again as the camshaft rotates completely around the longitudinal axis, thus the movement corresponds to one cycle.

[0037] According to another preferred embodiment of the invention, the width of the groove is chosen such that the camshaft disk is surrounded approximately without gaps. Here, the groove of at least one contact element can be lined with a corresponding device through which the camshaft disk contacts the groove in a way that reduces friction, or it can slide on the side surface. For example, the friction between the camshaft disk or the friction surface of the camshaft disk and the side surface of the groove can be reduced by selecting appropriate material pairings, wherein a lubricant can also be used to reduce friction.

[0038] Furthermore, it has proven advantageous that the height of the groove at least corresponds to the width of the groove. Particularly preferred is that the height is greater than the width of the groove, thereby ensuring that at least one lateral surface of the connecting side surface does not contact the camshaft disc.

[0039] Furthermore, it has proven advantageous that at least one propulsion tooth and / or rack tooth of each of the at least two propulsion elements are configured symmetrically and correspondingly.

[0040] According to a preferred embodiment, a slide is provided. Preferably, the slide includes one or more housing portions, wherein, more preferably, the drive shaft and / or at least two actuating teeth are held in a supported manner within the slide. Preferably, the slide includes a housing for receiving the actuating teeth, which may be composed of multiple housing portions. To support the drive shaft, at least one bearing may be provided in the slide, which may be configured, for example, as a sliding bearing or a rolling bearing. The slide can be securely coupled to the upper guide rail of the seat longitudinal adjustment device.

[0041] According to a preferred embodiment of the invention, the slide includes at least one linear guide device, by which at least two propulsion elements are linearly guided and held along the stroke axis. Furthermore, force is transmitted along the longitudinal axis between the slide and the at least two propulsion elements via the linear guide device.

[0042] According to a preferred improvement, the linear guide device has a contact surface, which is preferably flat, recessed, or convex, and the corresponding actuating element is form-fitted within a slide along both the longitudinal and transverse axes. Therefore, each of at least two actuating elements can only move along the stroke axis.

[0043] According to a preferred improvement, a driver is provided, wherein the driver drives the drive shaft.

[0044] Preferably, the drive is an electric drive, which is even more preferably coupled to the drive shaft via a transmission, especially a planetary gear transmission.

[0045] Another aspect of the invention relates to a seat longitudinal adjustment device having the aforementioned linear actuator. Preferably, the seat longitudinal adjustment device includes a lower guide rail and an upper guide rail that can be fixed to a chassis, wherein, even more preferably, the upper guide rail can be electrically moved by the linear actuator. In a preferred design, the lower guide rail may also include a rack, and the upper guide rail may include the remaining components of the linear actuator, particularly the actuation element and drive shaft.

[0046] The third and final aspect of the invention relates to a motor vehicle having at least one seat longitudinal adjustment device. Attached Figure Description

[0047] The following describes three embodiments of the present invention in detail with reference to the accompanying drawings. In the drawings:

[0048] Figure 1 A greatly simplified perspective view of a seat longitudinal adjustment device with a linear actuator is shown;

[0049] Figure 2 It shows according to Figure 1 An enlarged perspective view of a linear actuator having a rack oriented along a longitudinal axis, four propulsion elements, a drive shaft, and a slide housing the propulsion elements;

[0050] Figure 3 It shows according to Figure 1 and Figure 2 A simplified diagram of a linear actuator, in which the slide is hidden for better understanding;

[0051] Figure 4 A sectional view is shown in a plane transverse to the longitudinal axis;

[0052] Figure 5 It shows according to Figure 3 A simplified side view of the linear driver;

[0053] Figure 6 A simplified perspective view of the linear actuator according to the second embodiment is shown, wherein the slide is hidden for better understanding;

[0054] Figure 7 It shows according to Figure 6 A top view of the linear drive;

[0055] Figure 8 The following is shown in a plane transverse to the longitudinal axis. Figure 6 A cross-sectional view of a linear drive with a slide.

[0056] Figure 9 A simplified side view of the linear driver according to the second embodiment is shown;

[0057] Figure 10 A simplified perspective view of the linear actuator according to the third embodiment is shown, wherein the slide is hidden for better understanding;

[0058] Figure 11 It shows according to Figure 10 A top view of the linear drive;

[0059] Figure 12 A cross-sectional view of a linear actuator with a slide according to a third embodiment is shown in a plane transverse to the longitudinal axis;

[0060] Figure 13 A simplified side view of a linear driver according to a third embodiment is shown; and

[0061] Figure 14 Four detailed illustrations of different propulsion elements of the linear actuator according to the third embodiment are shown. Detailed Implementation

[0062] Hereinafter, components that are the same or have the same function will be identified by the same reference numerals. For clarity, not all components that are the same or have the same function will be labeled with reference numerals in each drawing.

[0063] Figure 1 The invention shows a longitudinal seat adjustment device 2 for a motor vehicle 3 (not shown), which has a linear actuator 1 configured for adjusting the seat (not shown) of the motor vehicle 3 along the longitudinal axis X.

[0064] The seat longitudinal adjustment device 2 may have a lower guide rail (not shown) connected to the chassis (not shown), and may have an upper guide rail (not shown) connected to the seat, wherein the upper guide rail is movable relative to the lower guide rail on the longitudinal axis X.

[0065] exist Figures 3 to 13 The linear drive 1 shown in detail in three different embodiments includes at least one rack 10, a drive shaft 20, and at least two propulsion elements 30.

[0066] Furthermore, the linear actuator 1 may include a bracket 50 that can support and hold the propulsion element 30 and the drive shaft 20. The slide 50 may be formed by two housing portions 54 and 56 that can be joined together in a plane perpendicular to the longitudinal axis X.

[0067] At least one rack 10 is arranged along a longitudinal axis X and has a plurality of teeth 15, which are preferably arranged equidistantly along the longitudinal axis X. The teeth 15 may have symmetrical tooth profiles with two contact surfaces 18 formed on the tooth sides, and tooth gaps 16 may be formed between the teeth.

[0068] The drive shaft 20 can be driven by the driver 60, wherein a transmission 65 is provided between the driver 60 and the drive shaft 20, through which desired deceleration or acceleration can be performed. The drive shaft 20 is arranged on a transverse axis Y perpendicular to the longitudinal axis X, wherein the transverse axis Y and the longitudinal axis X can cross a plane arranged parallel to the rack 10.

[0069] In the embodiments described below, the linear drive 1 has four propulsion elements 30. Each propulsion element 30 includes at least one propulsion tooth 35 and is linearly movable on a travel axis Z, which is transverse to the longitudinal axis X and oriented transversely to the drive shaft 20 or the transverse axis Y.

[0070] The corresponding propulsion element 30 can be held in the slide 50 guided by linear guides 52 on the stroke axis Z, wherein these linear guides 52 pre-determine the position of the corresponding propulsion element 30 on the transverse axis Y and the longitudinal axis X. The linear guides 52 can support the corresponding propulsion element 30 in a V- or U-shape, for example, on the support surface 32 in the front and / or rear end regions.

[0071] At least one propulsion tooth 35 is configured as a tooth 15 corresponding to the rack 10 and may have a symmetrical tooth profile with two contact surfaces 38 formed on the tooth flanks. For better understanding, the four propulsion elements 30 in the figures are given reference numerals with suffixes a, b, c, and d to identify the different movements during the cyclic stroke. These movements also... Figure 4 , Figure 8 , Figure 12 The arrows are used to represent the characters.

[0072] from Figure 3 It can be seen that the propulsion elements 30 are arranged horizontally to the longitudinal axis X, that is, parallel to each other and side by side or adjacent to each other on the transverse axis Y.

[0073] The propulsion element 30 is driven coupled to the drive shaft 20, thereby causing or being converted into cyclic translational motion along the stroke axis Z by the rotation of the drive shaft 20. During the process, the corresponding propulsion element 30 performs at least one cyclic motion, and during the cyclic motion, at least one rack 10 is inserted and extended to generate propulsion force on the longitudinal axis X. This cyclic stroke motion can be described, for example, as a complete cycle of a sine curve, wherein the corresponding propulsion element 30 inserts into the rack 10 or the tooth gap 16 once during the cyclic stroke motion, fully extends, and returns to the starting position once. However, within the scope of the invention, it is also possible for the corresponding propulsion element 30 to rotate... Multiple cyclical motions are performed during this period.

[0074] The cyclic stroke motion of at least two propulsion elements 30 is phase-shifted. This is performed, thereby causing the propulsion element 30 to extend into or out of the rack 10 at different angular positions on the drive shaft 20. (Refer to...) Figure 4 and Figure 5It can be seen that the propulsion elements 30a, 30b, 30c, and 30d extend into and out of the tooth gap 16 at different time points when the camshaft 20 is at a constant speed. Propulsion element 30a is fully extended and at its inflection point. Propulsion element 30d is fully extended and also at its inflection point. Propulsion element 30b is in a cyclic stroke motion when it extends, and propulsion element 30b is also in a cyclic stroke motion when it extends into the rack 10. Figure 5 In the diagram, these movements are represented by arrows.

[0075] The drive coupling between the drive shaft 20 and the corresponding propulsion element 30 is achieved by a guiding device, wherein the guiding device can effectively contact the corresponding propulsion element 30. Preferably, the guiding device has a friction surface that interacts with the corresponding friction surface of the propulsion element 30, wherein the friction surface of the drive shaft 20 predetermines the position of the propulsion element 30 on the vertical axis Z.

[0076] For this purpose, the corresponding friction surfaces can slide against each other, wherein the propulsion element 30 deflects during sliding in order to extend into or out of the rack.

[0077] Reference Figure 5 An exemplary design of coupling between a drive shaft 20 and a corresponding propulsion element 30 is shown, wherein the drive shaft 20 includes a camshaft and the corresponding propulsion element 30 has a groove 40.

[0078] The camshaft 22 can be formed from a plurality of camshaft disks 24, wherein, preferably, each propulsion element 30 is assigned one camshaft disk 24. The respective camshaft disks 24 are arranged anti-rotatably with respect to the drive shaft 20 and about the transverse axis Y at an angle β relative to each other. This allows for phase shifting during the cyclic stroke of the respective propulsion element. In the illustrated embodiment, each having a propulsion element 30, the angle β can be 90°.

[0079] according to Figure 3 and Figure 4 As shown in the diagram, the drive shaft 20 passes through the propulsion element 30 in the groove 40 and can be supported by bearings 58 on the side, preferably on both sides of the propulsion element 30.

[0080] See also Figure 13 The groove 40 can be formed as a through hole or a perforation. The groove 40 has a maximum width B on the longitudinal axis X and a height H on the travel axis Z. The groove 40 is surrounded by two side surfaces 42 and 43 on the longitudinal axis X and by two longitudinal surfaces 44 and 45 on the travel axis Z. The height H is preferably at least as large as the width B, and more preferably, the height H is greater than the width B, i.e., H ≥ B.

[0081] The drive coupling between the drive shaft 20 or camshaft 22 and the propulsion element 30 occurs in the groove 40 through effective contact between the friction surface of the camshaft disk 24 and the longitudinal surfaces 44, 45 of the groove 40. Through the coupling between the camshaft 22 and the corresponding propulsion element 30, the propulsion element 30 can be pressed into the rack 10 and then pressed out again without the need for a separate reset device.

[0082] To press in, a force of the camshaft disk 24 is applied to the longitudinal surface 44 facing the rack 10, and to press out, a force is applied to the longitudinal surface 45 away from the rack 10.

[0083] The camshaft disk 24 is designed such that at least one propulsion element 30 is pressed into and out of the rack 10 at a substantially constant speed as the drive shaft 20 rotates at a constant angular velocity. This results in the most linear or constant possible motion of the corresponding propulsion element 30 along the stroke axis Z.

[0084] More specifically, in the illustrated embodiment, the camshaft disk 24 is configured in a heart shape and has a first segment 26 and a second segment 27, each extending by a semicircle. The first segment 26 and the second segment 27 are mirror-symmetrically configured and approximately have a helical orientation. The helical orientation of the corresponding segments 26 and 27 is chosen such that the distance between the longitudinal axis X and the friction surface changes approximately constantly in the rotational direction as the rotational angle of the camshaft disk 24 increases. During constant rotation of the camshaft disk 24, the radius of the first segment 26 increases linearly with rotation, and the radius of the second segment 27 decreases linearly. The radii of the two segments 26 and 27 are chosen such that the distance between the two diametrical sides of the friction surface 16 approximately corresponds to the width B of the groove 25. Thus, when the camshaft disk 24 rotates, the center point of the surface of the camshaft disk 24 moves exactly parallel to the longitudinal axis X in the transverse direction Y.

[0085] A transition portion 28 is formed between the first segment 26 and the second segment 27, connecting the spiral direction. The transition portion 28 is formed with a transition radius and can approximately correspond to the width B of the groove 40 in the preferred and illustrated embodiment. To prevent the camshaft disc 24 from wedging or getting stuck in the groove 40, the transition portion 28 is selected such that the distance between two opposing transition portions 28 formed along the diameter is at least 90% of the width B of the groove 40, preferably greater than 95%.

[0086] In order to generate a corresponding propulsive force when the corresponding propulsion element 30 is pressed into the rack 10 or its tooth gap 16, the corresponding contact surfaces 18, 38 of the rack 10 and the propulsion element 30 or the propulsion tooth 35 must be offset from each other on the longitudinal axis X, wherein the offset amount ΔX is related to the phase offset. Directly related.

[0087] See Figure 3 ,according to Figures 3 to 6 In the embodiment, the offset ΔX is achieved by a helical tooth with a helix angle α.

[0088] All the propulsion teeth 35 are identical and also have helical teeth that correspond to the helical teeth of the rack 10. The helix angle α of the helical teeth is predetermined by the size and number of the propulsion elements 30, where y is the distance from the geometric center on the transverse axis Y between at least two propulsion elements 30, k is the number of propulsion elements 30, and x is the distance between two teeth 15 of the rack 10 on the longitudinal axis X.

[0089]

[0090] For the offset ΔX between the corresponding propulsion elements 30 generated from the helical tooth section, the following relationship is generated, where x is the distance between two teeth 15 of the rack 10, k is the number of propulsion elements, or n is the fraction of the phase offset:

[0091] or

[0092] Offset ΔX and according to Figure 3 It is related to the corresponding geometric center on the transverse axis Y of the corresponding tooth 15.

[0093] According to Figures 6 to 9 In the second embodiment, the offset ΔX is achieved by a plurality of racks 10, wherein racks 10′, 10″, 10″′ and 10″″ are assigned to corresponding actuating elements 30, which can extend into and out of the racks 10′, 10″, 10″′ and 10″″. Racks 10′, 10″, 10″′ and 10″″ can be constructed as individual components or as a single piece of integral component.

[0094] The teeth 15 of the propulsion tooth 35 and the rack teeth 10′, 10″, 10″′ and 10″″ all have straight tooth portions. In addition, the structure and function of the linear actuator 1 correspond to the first embodiment.

[0095] according to Figure 7 and Figure 9 The offset ΔX between the teeth 15 of racks 10′, 10″, 10″′ and 10″″ on the longitudinal axis X can be described by the following relationship, where x is the distance between two teeth 15 of rack 10, k is the number of propulsion elements or n is the fraction of the phase offset:

[0096] or

[0097] according to Figures 10 to 14 The third embodiment is characterized in that, from Figure 11 and Figure 13 As can be seen, the rack 10 has a continuous straight tooth section on the transverse axis Y. The offset ΔX is achieved by propulsion elements 30 of different designs, which are identified in the figure by reference numerals 30′, 30″, 30″′, and 30″″.

[0098] Reference Figure 14 It can be seen that there is an offset between the propulsion teeth 35 on the transverse axis Y from the propulsion elements 30′, 30″, 30″′, 30″″ to the propulsion elements 30′, 30″, 30″′, 30″″. According to Figure 14 The offset ΔX between the propulsion teeth 35 of the propulsion elements 30′, 30″, 30″″, and 30″″″ on the longitudinal axis X can be described by the following relationship, where x is the distance between two teeth 15 of the rack 10, k is the number of propulsion elements 30, or n is the fraction of the phase offset:

[0099] or

[0100] Furthermore, the structure of the linear driver 1 according to the third embodiment corresponds to the linear driver 1 described in detail above according to the first embodiment.

[0101] For the sake of completeness, it is noted here that combinations of these three embodiments are possible.

[0102] Explanation of reference numerals in the attached figures:

[0103] 1 Linear driver

[0104] 2. Seat longitudinal adjustment device

[0105] 3 Motor vehicles

[0106] 10 racks

[0107] 15 teeth

[0108] 16 tooth gaps

[0109] 18 Contact Surface

[0110] 20 drive shafts

[0111] 22 Camshaft

[0112] 24 Camshaft Disc

[0113] 26 First Section

[0114] 27 Part Two

[0115] 28. Transition Section

[0116] 30 Propulsion Components

[0117] 32 Support surface

[0118] 35 Propulsion teeth

[0119] 38 Contact Surface

[0120] 40 grooves

[0121] 42 side surfaces

[0122] 43 Side surfaces

[0123] 44 Longitudinal Surface

[0124] 45 Longitudinal surface

[0125] 50 Slide

[0126] 52 Linear Guide Device

[0127] 54. Shell section

[0128] 56. Shell section

[0129] 58 bearings

[0130] 60 drives

[0131] 65 transmission

[0132] i is the number of cyclic strokes of the propulsion element during the rotation of the drive shaft.

[0133] Number of propulsion elements 30

[0134] n Fraction of phase offset

[0135] The distance between x teeth 15 / 35

[0136] y distance

[0137] X longitudinal axis

[0138] Y-axis

[0139] Z-axis travel

[0140] ΔX offset

[0141] α Helix angle

[0142] β tooth face angle

[0143] Rotate

[0144] Phase shift

Claims

1. A linear driver (1) having: - At least one rack (10) arranged along a longitudinal axis (X) and having a plurality of teeth (15); - A drive shaft (20) arranged transversely to the longitudinal axis (X) on a transverse axis (Y); and - At least two propulsion elements (30), each of the at least two propulsion elements (30) having at least one propulsion tooth (35), -in, The at least two propulsion elements (30) are linearly movable along a stroke axis (Z), which is transverse to the longitudinal axis (X) and oriented transversely to the drive shaft (20). - wherein the at least two propulsion elements (30) are driven coupled to the drive shaft (20) such that the at least two propulsion elements (30) are driven to rotate around the drive shaft (20) The process performs at least one cyclic stroke and extends and retracts the at least one rack (10) to generate propulsion along the longitudinal axis (X), and - wherein the at least two propulsion elements (30) extend into and out of the at least one rack (10) with a phase offset. conduct.

2. The linear driver (1) according to claim 1, characterized in that, The following applies to the cyclic stroke motion of the at least two propulsion elements (30) relative to the drive shaft (20). phase shift 3. The linear driver (1) according to claim 1, characterized in that, At least one propulsion tooth (35) of one of the at least two propulsion elements (30) is arranged offset (ΔX) relative to the drive shaft (20) on the longitudinal axis (X) compared to at least one propulsion tooth (35) of the other of the at least two propulsion elements (30), and / or at least one tooth (15) of at least one rack (10) into which one of the at least two propulsion elements (30) can extend is arranged offset (ΔX) relative to at least one tooth (15) of at least one rack (10) into which the other of the at least two propulsion elements (30) can extend is arranged offset (ΔX) on the longitudinal axis (X).

4. The linear driver (1) according to claim 1, characterized in that, The at least one rack (10) and the at least two propulsion elements (30) have helical teeth with a helix angle (α).

5. The linear driver (1) according to claim 1, characterized in that, Each of the at least two propulsion elements (30) is provided with a rack (10), wherein the teeth (15) of the respective rack (10) have a phase offset on the longitudinal axis (X). The offset (ΔX).

6. The linear driver (1) according to claim 1, characterized in that, The at least two propulsion elements (30) have more than one propulsion tooth (35).

7. The linear driver (1) according to any one of the preceding claims, characterized in that, The at least two propulsion elements (30) are identical.

8. The linear driver (1) according to any one of claims 1-6, characterized in that, The at least two propulsion elements (30) are arranged transversely to the longitudinal axis (X) and parallel to each other and adjacent to each other.

9. The linear driver (1) according to any one of claims 1-6, characterized in that, The at least two propulsion elements (30) each have a groove (40), and the drive shaft (20) is driven coupled to the corresponding propulsion element (30) in the groove (40).

10. The linear driver (1) according to claim 9, characterized in that, The drive shaft (20) includes a camshaft (22), and the drive shaft (20) is driven coupled to the at least two propulsion elements (30) via the camshaft (22).

11. The linear driver (1) according to claim 10, characterized in that, The camshaft (22) includes at least two camshaft disks (24) arranged laterally and parallel to the longitudinal axis (X) and spaced apart.

12. The linear driver (1) according to claim 11, characterized in that, The at least two camshaft disks (24) are arranged at an angle (β) offset around the longitudinal axis (X).

13. The linear driver (1) according to claim 11, characterized in that, The at least two camshaft disks (24) are configured asymmetrically around the longitudinal axis (X).

14. The linear driver (1) according to claim 11, characterized in that, The at least two camshaft disks (24) are designed such that the at least two propulsion elements (30) are pressed into and out of the rack (10) at substantially a constant speed as the camshaft (20) rotates at a constant angular velocity.

15. The linear driver (1) according to claim 11, characterized in that, The camshaft disk (24) has a guide device that pre-determines the rotation of the drive shaft (20). The cyclical movement during the period.

16. The linear driver (1) according to claim 15, characterized in that, The guide device on the camshaft disk (24) is configured in the rotational direction at a distance (A) from the longitudinal axis (X), and the change of the distance (A) is approximately linear in the rotational direction in at least one first section (26) and linear in the rotational direction in at least one second section (27).

17. The linear driver (1) according to claim 16, characterized in that, The at least one first segment (26) and the at least one second segment (27) are connected by a rounded transition section (28).

18. The linear driver (1) according to claim 17, characterized in that, The first segment (26) extends through a first semicircle, and the second segment (27) extends through a second semicircle.

19. The linear driver (1) according to claim 11, characterized in that, The width (B) of the groove (40) is chosen such that the camshaft disk (24) is surrounded approximately without gaps.

20. The linear driver (1) according to claim 11, characterized in that, The height (H) of the groove (40) is chosen such that the camshaft disk (24) is approximately non-contact.

21. The linear driver (1) according to any one of claims 1-6, characterized in that, The corresponding propulsion teeth (35) and / or the teeth (15) are configured symmetrically and correspondingly.

22. The linear driver (1) according to any one of claims 1-6, characterized in that, A slide (50) is provided, and the drive shaft (20) and at least two of the propulsion teeth are held in the slide (50) in a supported manner.

23. The linear driver (1) according to claim 22, characterized in that, The slide (50) has at least one linear guide device (52), and the at least two propulsion elements (30) are linearly guided by the linear guide device (52) on the stroke axis (Z).

24. The linear driver (1) according to any one of claims 1-6, characterized in that, A driver (60) is provided, wherein the driver (60) drives the drive shaft (20).

25. A seat longitudinal adjustment device (2) having a linear actuator (1) according to any one of the preceding claims.

26. A motor vehicle (3) having a linear drive (1) according to any one of claims 1 to 24 and a seat longitudinal adjustment device (2) according to claim 25.

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