Longitudinal adjustment device for a vehicle seat

Abstract

A longitudinal adjustment device (1) for a vehicle seat (2) comprises: a first adjustment element (11A) guided on a first rail (10A), a second adjustment element (11B) guided on a second rail (10B), a first drive device (12A) by means of which the first adjustment element (11A) is adjustable along the first rail (10A), and a second drive device (12B) by means of which the second adjustment element (11B) is adjustable along the second rail (10B), wherein a control unit (120A) of the first drive device (12A) is in communicative contact with a control unit (120B) of the second drive device (12B).

Description

[0001] The invention relates to a longitudinal adjustment device for a vehicle seat and a vehicle seat with such a longitudinal adjustment device.

[0002] Longitudinal adjustment mechanisms are typically used in vehicle seats to adjust a seat cushion and backrest along the vehicle's length, for example, to provide the occupant with more or less legroom as needed. Motorized longitudinal adjustment mechanisms, in which the adjustment is performed by an electric motor, offer a high level of comfort. Longitudinal adjustment mechanisms usually have at least two transversely spaced rails, each with an adjustment element guided along them. The adjustment elements can be designed as seat rails that engage with their respective rails. In practice, an electric motor is typically positioned, for example, in a space between the two rails and connected to the adjustment elements via a shaft, allowing the electric motor to move the two adjustment elements along the rails.

[0003] In some applications, however, it is desirable to leave a free space between the rails; or the space between the rails is blocked by fixed parts. In both cases, a mechanical coupling of the single electric motor with the two adjustment elements is typically not feasible or only achievable with considerable effort.

[0004] Therefore, in some cases it may be useful to provide two electric motors, one for each of the two adjustment elements.

[0005] A longitudinal adjustment device with two separate drive units, each with its own drive motor, is described in DE 198 60 910 B4. To ensure synchronous rotation of the two drive motors, this document proposes the use of a mechanical synchronizing shaft between them. However, this offers little advantage over a drive using only one common motor. Alternatively, the document suggests a control unit electrically connected to both drive motors and to the respective devices for detecting a relative position. This, however, typically requires more complex wiring.

[0006] The solution described in DE 10 2008 007 267 B4 has similar disadvantages. There, two motors are connected in series or parallel and controlled via switches.

[0007] The task is to provide an improved longitudinal adjustment device.

[0008] This problem is solved by an object having the features of claim 1.

[0009] A longitudinal adjustment device for a vehicle seat comprises a first adjustment element guided on a first rail, a second adjustment element guided on a second rail, a first drive device by means of which the first adjustment element can be adjusted along the first rail, and a second drive device by means of which the second adjustment element can be adjusted along the second rail. It is provided that a control unit of the first drive device is in communicative communication with a control unit of the second drive device.

[0010] By providing two separate drive units, one for the first adjustment element and one for the second, the space between the rails can be used for other purposes. Furthermore, since each drive unit is controlled by its own control unit, the cabling for communication between them can be adapted to the specific application with exceptional flexibility and simplicity, for example, using just a few small-diameter wires or an optical fiber. Alternatively, a wireless communication link is even possible. Existing communication infrastructure within the vehicle can also be used, allowing for particularly easy integration.

[0011] The control unit of the second drive device can be configured to synchronize the movement of the second adjusting element with the movement of the first adjusting element via communication. Thus, the first drive device initiates a movement, and the second drive device executes it. The first drive device therefore operates as the "master," and the second as the "slave." The second drive device follows the control input of the first drive device.

[0012] Optionally, the control unit of the first drive device is configured to determine the position of the first adjustment element along the first rail and communicate this position to the control unit of the second drive device. This enables efficient control and communication.

[0013] The control unit of the second drive device, for example, controls a drive motor of the second drive device based on the position communicated by the control unit of the first drive device. This enables precise control.

[0014] For example, the control unit of the second drive device is configured to calculate a target speed for the drive motor of the second drive device based on the position communicated by the control unit of the first drive device. The drive motor of the second drive device can then be controlled based on this target speed. This allows the second adjusting element to follow the first adjusting element quickly and precisely.

[0015] Furthermore, the control unit of the second drive device can be configured to use the position communicated by the control unit of the first drive device as the target position for the second adjustment element along the second rail. In this way, the second control unit always moves to the last communicated position. This allows for precise and robust control.

[0016] Optionally, the control unit of the second drive device is configured to calculate a pulse width modulation signal (e.g., based on the calculated target speed). This allows, for example, the control of a brushless DC motor (BLDC motor) as a drive motor.

[0017] Optionally, the control unit of the first drive device communicates with the control unit of the second drive device via a bus system. This allows for a particularly simple design, because such a bus system is often already in place and can frequently be connected with short cable runs.

[0018] For example, the bus system is designed as a LIN (Local Interconnect Network) bus system. This allows for a particularly simple design. Alternatively, a CAN bus would also be conceivable. A bus system based on CAN FD, FlexRay, Ethernet, K-line, or MOST is also possible. The described longitudinal adjustment device enables electronic synchronization via a low-band bus system. It is possible to use an existing bus system, which minimizes the effort required.

[0019] The control unit of the first drive device can communicate with the control unit of the second drive device via a gateway. The gateway can, for example, establish the communication between the control units. For instance, the gateway provides a clock signal for the communication. The gateway can be a LIN bus commander, while the control units can be simple LIN bus responders.

[0020] The control unit of the first drive device can communicate with the control unit of the second drive device unidirectionally or bidirectionally. In a bidirectional communication link, for example, the control unit of the second drive device can transmit feedback on performed adjustment movements and / or an error message to the control unit of the first drive device. This allows for further improvements in functionality and robustness.

[0021] Optionally, the control unit of the first drive device is configured to communicate data frames containing control data to the control unit of the second drive device at timed intervals. This allows the control unit of the second drive device to gradually replicate the movements controlled by the control unit of the first drive device.

[0022] In a further development process, it is stipulated that the control unit of the second drive device is configured to interpolate between the control data contained in two successive data frames for a period of time. This enables particularly smooth control, even under heavy load on the communication channel between the control units, e.g., the LIN bus system.

[0023] The control unit of the second drive device can be configured to detect a fault and communicate it to the control unit of the first drive device. This ensures a particularly high level of safety and robustness for the longitudinal adjustment device.

[0024] According to one aspect, a vehicle seat is specified comprising a seat part, a backrest and the longitudinal adjustment device according to any embodiment described herein, wherein at least the seat part (in particular the seat part and the backrest) is mounted on the adjustment elements of the longitudinal adjustment device.

[0025] The attached figures illustrate possible implementation variants of the proposed solution.

[0026] This shows: Fig. 1 a vehicle with a longitudinally adjustable vehicle seat; Fig. 2 a longitudinal adjustment device of the vehicle seat according to Fig. 1; Fig. 3 control units of the longitudinal adjustment device according to Fig. 2, which are in communicative contact with each other; Fig. 4 a control of a drive motor of the longitudinal adjustment device according to Fig. 2; and Fig. 5 a sequence of messages sent via a bus system between the control units of the longitudinal adjustment device according to Fig. 3.

[0027] Fig. Figure 1 shows a vehicle 3 as an example in the form of a passenger car. The vehicle 3 includes several vehicle seats 2, of which in Fig. 1 is depicted.

[0028] The vehicle seat 2 comprises a seat section 20 and a backrest 21. In the example shown, the backrest 21 is pivotally mounted on the seat section 20. Furthermore, the vehicle seat 2 includes a longitudinal adjustment device 1.

[0029] The seat section 20 and the backrest 21 can be moved along a longitudinal axis by means of the longitudinal adjustment device 1. For this purpose, the longitudinal adjustment device 1 comprises two rails 10A, 10B, of which a first rail 10A is shown in the side view of the Fig. 1 is visible. A second rail 10B runs parallel to the first rail 10A (and spaced apart from the first rail 10A), as shown, for example, by Fig. 2 can be seen.

[0030] Rails 10A and 10B are attached to a substructure 31 of the vehicle 3. The substructure 31 forms part of the vehicle 3's body or is alternatively attached to it. An adjustment element 11A or 11B is guided slidably along each rail 10A or 10B. Thus, a first adjustment element 11A is guided on the first rail 10A, and a second adjustment element 11B is guided on the second rail 10B. In the side view of the Fig. In 1 the first adjusting element 11A is visible, the second adjusting element 11B is again in Fig. 2 recognizable.

[0031] In the present case, the adjusting elements 11A, 11B have a rail-shaped section which is longitudinally displaceable in engagement with the respective rail 10A, 10B, as shown in Fig. 2. A support section of each adjustment element 11A, 11B is firmly connected to the respective rail-shaped section. In this case, the two support sections of the adjustment elements 11A, 11B extend through a vehicle floor 30. The vehicle floor 30 comprises, for example, a carpet. This allows the rails 10A, 10B to be arranged under the vehicle floor 30 and thus be invisible to passengers. Such a design facilitates cleaning of the vehicle 3 and also allows for the creation of particularly long rails 10A, 10B. This enables particularly wide adjustment ranges, which allows for greater flexibility in the use of the vehicle's interior.

[0032] The seat section 20 is supported on the adjustment elements 11A, 11B, in the example shown via an (optional) height adjustment device. The seat section 20 is mounted on the adjustment elements 11A, 11B (here height-adjustable). The seat section 20 can be attached to the adjustment elements 11A, 11B.

[0033] Fig. Figure 2 shows the longitudinal adjustment device 1 in a view along the longitudinal extent of the rails 10A, 10B. Fig. 2 It is also apparent that the longitudinal adjustment device 1 further comprises a first drive device 12A, by means of which the first adjustment element 11A is adjustable along the first rail 10A, and a second drive device 12B, by means of which the second adjustment element 11B is adjustable along the second rail 10B.

[0034] Each of the drive devices 12A, 12B includes its own drive motor 121. The longitudinal adjustment device 1 thus has two drive motors 121, which are optionally identical in construction, as in the example shown.

[0035] Each of the drive motors 121 drives (via a gearbox) a shaft 122. The respective shaft 122 in turn drives a worm gear 123, which meshes with a corresponding spindle nut 124. In the example shown, the spindle nuts 124 are rotatably mounted on the corresponding adjusting element 11A, 11B and engage with a spindle 124, which is arranged on and fixed relative to the corresponding rail 10A, 10B. Activation of the drive motor 121 of the first drive device 12A thus causes the spindle nut 124 to be screwed along the corresponding spindle 124. In doing so, the spindle nut 124 engages the first adjusting element 11A. Activation of the drive motor 121 of the second drive device 12A analogously causes the corresponding spindle nut 124 to be screwed along the associated spindle 124, whereby this spindle nut 124 takes the second adjusting element 11A with it.It should be noted that this arrangement is only an example. Alternatively, for instance, each worm 123 could mesh with a gear attached to a spindle rotatably mounted relative to the corresponding rail 10A, 10B, so that the spindles would be set into rotation by means of the then stationary drive motors. A spindle nut engaging with the corresponding spindle would then be attached to the corresponding adjusting element 11A, 11B.

[0036] The drive motor 121 of the first drive device 12A is arranged adjacent to the first adjusting element 11A (and to the first rail 10A), while the drive motor 121 of the second drive device 12B is arranged adjacent to the second adjusting element 11B (and to the second rail 10B). The drive motor 121 of the first drive device 12A is arranged closer to the first adjusting element 11A (and to the first rail 10A) than the drive motor 121 of the second drive device 12B. The drive motor 121 of the second drive device 12B is arranged closer to the second adjusting element 11B (and to the second rail 10B) than the drive motor 121 of the first drive device 12A.

[0037] By providing two independent drive motors 121, no torque transmission is required between the drive devices 12A, 12B and the adjusting elements 11A, 11B. The described arrangement therefore leaves space between the two rails 10A, 10B free, which can be used for other purposes, such as part of a traction battery, a fan duct, or the like. This is illustrated in Fig. Figure 2 schematically illustrates an obstacle H. In contrast, a mechanical coupling of the drives of the adjusting elements 11A, 11B would have to be moved along the longitudinal axis in the area of ​​the obstacle H.

[0038] To enable a simultaneous movement of the two adjusting elements 11A and 11B despite the absence of mechanical torque transmission, a control unit 120A of the first drive device 12A is in communicative contact (directly or indirectly, e.g., via a gateway) with a control unit 120B of the second drive device 12B. The two control units 120A and 120B can exchange data with each other, in this case bidirectionally. The control unit 120A of the first drive device 12A is configured to send data to the control unit 120B of the second drive device 12B, which is configured to receive and process the data.In the described example, the control unit 120B of the second drive device 12B is also configured to send data to the control unit 120A of the first drive device 12A, which is likewise configured to receive and process the data sent to it.

[0039] For this purpose, the two control units 120A and 120B are connected to a communication system. In general, a wired, optical, or wireless communication system would be conceivable. In the example shown, the control units 120A and 120B are connected to a common bus system 13.

[0040] In this case, bus system 13 is a LIN bus. A LIN bus has a simple structure, is relatively inexpensive, and is already present in many vehicles. Therefore, the two control units 120A and 120B can be easily connected for communication. The two control units 120A and 120B communicate using a predefined transmission protocol. Specifically, the two control units 120A and 120B exchange data packets in the form of data frames. Depending on the design of the communication system, the data packets could be exchanged directly between the two control units 120A and 120B. In this example of bus system 13, which is configured as a LIN bus, a gateway 130 is provided within the bus system 13, which mediates the data frames between the two control units 120A and 120B.

[0041] To synchronize the movements of the two adjusting elements 11A and 11B, a master-slave principle is provided, whereby one of the control units 120A, 120B (namely, control unit 120A of the first drive device 12A) specifies an adjustment, and the other of the two control units 120A, 120B (namely, control unit 120B of the second drive device 12B) follows this adjustment. The control unit 120B of the second drive device 12B is therefore configured to synchronize a movement of the second adjusting element 11B with a movement of the first adjusting element 11A via the communication link through the bus system 13.

[0042] For this purpose, the control unit 120A of the first drive device 12A is configured to determine the position of the first adjusting element 11A along the first rail 10A and to communicate this position to the control unit 120B of the second drive device 12B using a data frame. To ensure the most uniform movement possible, the control unit 120A of the first drive device 12A is configured to communicate several successive data frames, each containing an updated position, to the control unit 120B of the second drive device 12B, for example, in a periodic sequence.

[0043] Since the control unit 120B of the second drive device 12B reacts to the position of the first adjustment element 11A, the second adjustment element 11B follows the first adjustment element 11A, while the first adjustment element 11A (slightly) leads. Due to the fast communication via the bus system 13, communication occurs with low latency. Thus, the communication of a data packet from the control unit 120A of the first drive device 12A to the control unit 120B of the second drive device 12B takes place within less than 100 ms, in particular within less than 40 ms, typically within 20 ms. The positional difference is therefore generally imperceptible to a seat user and can be compensated for by the elasticity of the seat section 20 of the vehicle seat 2 without the need for any special measures.However, if an alternative communication system with a comparatively high latency were to be used, the use of one or more elastic compensation elements would be conceivable, which could be mounted, for example, between one or more adjustment elements 11A, 11B and the seat part 20.

[0044] The described communication between the two control units 120A and 120B is in Fig. Figure 3 illustrates which figure is now being referred to.

[0045] First, a control command B is sent to the control unit 120A of the first drive device 12A. This can be done particularly simply by actuating a switch, which is held down, for example, for as long as an adjustment is desired. The control unit 120A then controls the drive motor 121 of the first drive device 12A to effect an adjustment in the direction corresponding to the switch.

[0046] Alternatively (or additionally) to a control command B via a switch, it can be provided that a control command with a data frame 400 can be transmitted to the control unit 120A via the bus system 13. For example, an external control unit can be used to communicate that a specific, e.g., preset, position is to be moved to. The control unit 120A of the first drive device 12A then causes the first adjusting element 11A to move to this position. The transmission of the data frame 400 takes place, for example, via the gateway 130 (or alternatively via another route).

[0047] To synchronize the movements of the two adjustment elements 11A and 11B, the control unit 120A of the first drive device 12A (at least during a movement of the first adjustment element 11A) sends data frames 401 containing control data to the control unit 120B of the second drive device 12B (via the gateway 130) at regular intervals. The data frames contain digital data. The control units 120A and 120B communicate digitally with each other. A data frame 401 comprises a predetermined number of bits. In this example (but not necessarily), the data frames 401 each have a header and a data part. The data part has, for example, a size of 8 bytes (or up to 8 bytes).

[0048] Each data frame 401 includes a current position of the first adjusting element 11A and / or a current adjusting speed of the first adjusting element 11A (e.g., in the form of a current rotational speed) and / or a control mode and / or a possible fault condition. In particular, each data frame 401 can contain all of these data.

[0049] The control unit 120A of the first drive device 12A detects the current position of the first adjusting element 11A, e.g., by counting the revolutions of a moving part of the first drive device 12A, optionally using a position sensor, and / or the current adjustment speed of the first adjusting element 11A (e.g., in the form of a currently set rotational speed) and / or the currently set control mode and / or any possible error condition, and writes this data to a data frame 401, which it sends to the control unit 120B of the second drive device 12B. The control mode can, for example, indicate standstill, speed-controlled adjustment, or position-controlled adjustment. Furthermore, the control mode can indicate a normalization run, in which the drive travels to a stop.

[0050] The control unit 120B of the second drive device 12B receives the data frames 401 and processes them as described below with reference to Fig. 4 will be explained in more detail.

[0051] After receiving and processing each data frame 401, the control unit 120B of the second drive device 12B sends a data frame 402 to the control unit 120A of the first drive device 12A. The data frames 402 each contain the current position of the second adjusting element 11B and / or the current adjustment speed of the second adjusting element 11B (e.g., in the form of a current rotational speed) and / or a set control mode and / or a possible error state. In particular, the data frames 402 can each contain all of this data. The data frames 402 serve primarily as feedback. Based on this feedback, the control unit 120A of the first drive device 12A can determine whether the movement of the two adjusting elements 11A, 11B is synchronized (within the latency of the communication between the control units 120A, 120B).This allows the control unit 120A of the first drive device 12A to detect a fault and react accordingly, e.g., by stopping. However, such feedback is optional, and it could also be intended that communication is unidirectional, only between the control unit 120A of the first drive device 12A and the control unit 120B of the second drive device 12B.

[0052] Fig. Figure 4 shows an exemplary control system for synchronizing the movement by the control unit 120B of the second drive device 12B. Part of the control system is implemented using software (SW), but this is only an example. The control unit 120B comprises a memory on which the software (SW) is stored and a processor that executes the software (SW).

[0053] As soon as a data frame 401 is received, the control unit 120B reads the current position of the first adjusting element 11A POS_1 stored within it. This is then fed into a position controller 500, which also receives the current position of the second adjusting element 11B POS_2. The control unit 120B measures the current position of the second adjusting element 11B POS_2 in the same way that the control unit 120A measures the current position of the first adjusting element 11A of the first drive device 12A (see above). Based on these two positions POS_1 and POS_2, the position controller 500 calculates a target speed. If the two positions POS_1 and POS_2 are identical, the target speed is, for example, zero. The greater the difference between the two positions POS_1 and POS_2, the higher the target speed.

[0054] The target speed is provided by the position controller 500 to a speed controller 501. This controller also receives the current (actual) speed DZ of the second drive unit 12B. Based on the target speed and the current speed DZ, the speed controller 501 calculates a target current and provides this to a current controller 502. This controller also receives the current I of the second drive unit 12B. Based on the target current and the current, the current controller 502 calculates a pulse-width modulation (PWM) signal, which is transmitted to the hardware of the second drive unit 12B to initiate the corresponding movement of the drive motor 121. As an intermediate step, a voltage can also be calculated from the current values.

[0055] The drive motors 121 are brushless DC motors (BLDC motors). However, it should be noted that other types of motors can also be used; the control system according to the position controller 500 can then be configured accordingly. Furthermore, it should be noted that position control is not strictly necessary; direct synchronization of the speeds could also be performed. However, position control allows for particularly precise synchronization with only a negligible latency-related offset of the adjustment elements 11A and 11B.

[0056] Fig.Figure 5 illustrates a possible communication flow during adjustment. First, data frame 400 is transmitted with a control command from gateway 130 to the control unit 120A of the first drive device 12A. This then starts the adjustment of the first adjustment part 11A and sends data frame 401 with the current status of the first adjustment part 11A via gateway 130 to the control unit 120B of the second drive device 12B. Optionally, gateway 130 processes the content of data frame 401 and creates a new data frame for transmission to the control unit 120B of the second drive device 12B. The control unit 120B of the second drive device 12B then regulates the operation of the drive motor 121 of the second drive device 12B according to the data contained in data frame 401.Finally, the control unit 120B of the second drive device 12B sends the data frame 402 with the current status of the second adjustment part 11B via the gateway 130 to the control unit 120A of the first drive device 12A. This (or at least the transmission of the data frame 401) occurs periodically, at least until the end of the adjustment.

[0057] The control unit 120B of the second drive device 12B is configured to interpolate between the control data contained in two successive data frames 401 for a period of time between them.

[0058] Furthermore, by implementing direction-dependent and / or load-dependent situations, deliberate position settings can be achieved via the position control system. A number of respective control inputs in a specific direction can be taken into account.

[0059] Electronic synchronization (with flexibility through a software-based implementation) allows for influence on the position of the mechanics.

[0060] This ensures symmetrical wear and improves service life.

[0061] The described communication and control allow the use of a bus system 13 with a relatively low bandwidth and therefore relatively low resolution of the position of the first adjusting part 11A and speed of the first drive device 12A.

[0062] The described longitudinal adjustment device 1 allows for a particularly high degree of flexibility in its implementation and also a reduction of mechanical stresses, thereby improving the service life. Reference symbol list 1 Longitudinal adjustment device 10A, 10B first, second rail 11A, 11B first, second adjusting element 12A, 12B first, second drive device 120A, 120B control unit 121 Drive motor 122 wave 123 snail 124 Spindle nut 125 spindle 13 Bus system 130 Gateway 2 vehicle seats 20 Seat section 21 Backrest 3 vehicles 30 Vehicle floor 31 Substructure 400-402 data frame 500 position controllers 501 Speed ​​controller 502 Current regulator B Control command DZ speed H obstacle HW Hardware I Current intensity POS_1, POS_2 Position first, second adjustment element PWM pulse width modulation signal SW Software QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 198 60 910 B4

[0005] DE 10 2008 007 267 B4

[0006]

Claims

[1] Longitudinal adjustment device (1) for a vehicle seat (2), comprising: - a first adjusting element (11A) guided on a first rail (10A), - a second adjusting element (11B) guided on a second rail (10B), - a first drive device (12A) by means of which the first adjusting element (11A) can be adjusted along the first rail (10A), and - a second drive device (12B) by means of which the second adjusting element (11B) can be adjusted along the second rail (10B), characterized by that a control unit (120A) of the first drive device (12A) is in communicative connection with a control unit (120B) of the second drive device (12B). [2] Longitudinal adjustment device (1) according to claim 1, characterized bythat the control unit (120B) of the second drive device (12B) is configured to synchronize a movement of the second adjusting element (11B) with a movement of the first adjusting element (11A) by means of the communicative connection. [3] Longitudinal adjustment device (1) according to claim 1 or 2, characterized by that the control unit (120A) of the first drive device (12A) is configured to determine a position of the first adjusting element (11A) along the first rail (10A) and to communicate the position to the control unit (120B) of the second drive device (12B). [4] Longitudinal adjustment device (1) according to claim 3, characterized by that the control unit (120B) of the second drive device (12B) is configured to control a drive motor (121) of the second drive device (12B) based on the position communicated by the control unit (120A) of the first drive device (12A). [5] Longitudinal adjustment device (1) according to claim 4, characterized by that the control unit (120B) of the second drive device (12B) is configured to calculate a target rotational speed for the drive motor (121) of the second drive device (12B) based on the position communicated by the control unit (120A) of the first drive device (12A). [6] Longitudinal adjustment device (1) according to claim 4 or 5, characterized by that the control unit (120B) of the second drive device (12B) is configured to use the position communicated by the control unit (120A) of the first drive device (12A) as the target position for the second adjustment element (11B) along the second rail (10B). [7] Longitudinal adjustment device (1) according to one of the preceding claims, characterized bythat the control unit (120B) of the second drive device (12B) is configured to calculate a pulse width modulation signal (PWM) based on the calculated target rotational speed. [8] Longitudinal adjustment device (1) according to one of the preceding claims, characterized by that the control unit (120A) of the first drive device (12A) is communicatively connected to the control unit (120B) of the second drive device (12B) by means of a bus system (13). [9] Longitudinal adjustment device (1) according to claim 8, characterized by that the bus system is designed in the form of a LIN, CAN, CAN FD, FlexRay, Ethernet, K-line or MOST bus system. [10] Longitudinal adjustment device (1) according to one of the preceding claims, characterized bythat the control unit (120A) of the first drive device (12A) is communicatively connected to the control unit (120B) of the second drive device (12B) via a gateway (130). [11] Longitudinal adjustment device (1) according to one of the preceding claims, characterized by that the control unit (120A) of the first drive device (12A) is bidirectionally communicatively connected to the control unit (120B) of the second drive device (12B). [12] Longitudinal adjustment device (1) according to one of the preceding claims, characterized by that the control unit (120A) of the first drive device (12A) is configured to communicate data frames (401) with control data to the control unit (120B) of the second drive device (12B) at time intervals. [13] Longitudinal adjustment device (1) according to claim 12, characterized bythat the control unit (120B) of the second drive device (12B) is configured to interpolate between the control data contained therein for a period of time between two consecutive data frames (401). [14] Longitudinal adjustment device (1) according to one of the preceding claims, characterized by that the control unit (120B) of the second drive device (12B) is configured to detect an error and to communicate with the control unit (120A) of the first drive device (12A). [15] Vehicle seat (2) with a seat part (20), a backrest (21) and the longitudinal adjustment device (1) according to one of the preceding claims, wherein at least the seat part (20) is mounted on the adjustment elements (11A, 11B) of the longitudinal adjustment device (1).

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