Steering column and method for detecting pressure when adjusting a steering column

Abstract

The invention relates to a method for detecting a crush condition during electromechanical adjustment of a steering column in a motor vehicle by means of at least one electric motor, in which, during an adjustment operation, a current signal is sensed for the at least one electric motor and a gradient of the current signal is evaluated, in which, during the evaluation of the gradient of the current signal, the steering column in the motor vehicle is subjected to electromechanical adjustment. It is checked whether a gradient of the current signal is within a predetermined limit, where a squeeze condition is detected when the gradient of the current signal is within the predetermined limit. The invention also relates to an adjustable steering column for a motor vehicle, comprising a support unit by means of which an actuator is held in an adjustable manner, and an adjustment device designed to adjust the actuator relative to the support unit, the adjustment device for adjusting the actuator comprising at least one electric motor, a control unit is assigned to the steering column. The steering column is designed to perform the method as described above.

Description

Technical Field

[0001] The present invention relates to a method for detecting compression during electromechanical adjustment of a steering column in a motor vehicle by means of at least one electric motor, wherein, during the adjustment operation, a current signal is sensed for at least one electric motor and the gradient of the current signal is evaluated.

[0002] Furthermore, the present invention relates to an adjustable steering column for a motor vehicle, the steering column comprising: a support unit through which an actuator is held in an adjustable manner; and an adjustment device designed to adjust the actuator relative to the support unit, wherein the adjustment device for adjusting the actuator includes at least one electric motor, and the steering column is provided with a control unit. Background Technology

[0003] In the prior art, US2018 / 0079441 A1 discloses a steering column adjustable between a retracted position and an operating position. Furthermore, DE 10 2019 108 466A1 discloses an adjustable steering column for a motor vehicle having an actuator and a support unit, wherein the steering column can be moved to a retracted position. The position of the actuator relative to the support unit is determined by means of a position detection device, wherein the actuator is adjusted taking the determined position into account.

[0004] Furthermore, for steering wheel devices with electrically adjustable steering wheels, EP 3 042 825A1 discloses detecting contact or resistance when the steering wheel is retracted, and returning the steering wheel to the operating position upon such detection. Additionally, DE10 2022 125 280A1 discloses a method for detecting the compression of a vehicle's steering column, wherein, for the electric motor of the steering column, the current conversion rate and speed conversion rate are sensed and evaluated via threshold comparison.

[0005] In this context, the present invention solves the problem of better detecting squeeze during the adjustment of the adjustable steering column of a motor vehicle, and in particular, reduces the number of false squeeze detections. Summary of the Invention

[0006] To address this problem, a method for detecting compression during electromechanical adjustment of a steering column in a motor vehicle, according to a first aspect of the invention, and an adjustable steering column for a motor vehicle, according to an additional aspect of the invention, are proposed. Other advantageous improvements of the invention are described in other aspects and the specification and illustrated in the accompanying drawings.

[0007] The proposed solution provides a method for detecting squeezing during electromechanical adjustment of a steering column in a motor vehicle by means of at least one electric motor, particularly during adjustment of the steering column between a retracted position and an operating position. During the adjustment operation, a current signal is sensed for at least one electric motor, and the gradient of this current signal is evaluated. During the evaluation of the gradient of the current signal, it is checked whether the gradient of the current signal is within a predetermined limit, wherein squeezing is detected when the gradient of the current signal is within the predetermined limit. Advantageously, it is specifically checked whether the gradient of the sensed current signal has exceeded a lower limit, but the sensed gradient of the current signal is below an upper limit. It has been found that by checking whether the gradient of the current signal is within the predetermined limit, false detection of squeezing can be prevented, because current fluctuations, particularly those attributable to mechanical effects during steering column adjustment, can be better excluded as possible triggers for detecting squeezing. Therefore, for example, adjusting the steering column until it acts as a limiter in the form of a hard stop may result in a steep gradient in the current signal, where the upper limit of the predetermined limit is then advantageously limited, such that in this case the detected gradient exceeds the upper limit and therefore no squeezing is detected. In particular, squeezing occurs when the steering column is adjusted against resistance caused by an obstacle, i.e., particularly when it comes into contact with the driver's body during adjustment.

[0008] According to an advantageous improvement of the method, the limits are predetermined by a first gradient line forming an upper limit and a second gradient line forming a lower limit. Advantageously, a squeezing condition is detected when the gradient of the sensed current signal is between the first and second gradient lines. If the gradient exceeds or at least continuously exceeds the first gradient line, a squeezing condition is therefore specifically not detected. Correspondingly, a squeezing condition is specifically not detected when the gradient of the sensed current signal is below the second gradient line. Since the gradient lines serve as upper and lower limits, the number of incorrectly detected squeezing conditions can be advantageously further reduced.

[0009] Advantageously, the first gradient line is a portion of the first gradient curve, particularly a portion of the first gradient straight line, and the second gradient line is a portion of the second gradient curve, particularly a portion of the second gradient straight line. Advantageously, the gradient lines can be defined relatively easily in this way. Furthermore, the gradient lines can be better adapted, making it easier to distinguish between extrusion and non-extrusion conditions. In particular, the gradient of the first gradient line is greater than the gradient of the second gradient line.

[0010] According to another advantageous aspect of the invention, the limit is predetermined. Advantageously, in this process, particularly due to the corresponding actuation of at least one electric motor, the steering column impacts the obstacle in each of the multiple adjustment operations during adjustment. In this case, the obstacle specifically simulates a possible real obstacle, especially a part of the human body. Then, advantageously, the current signal generated by the at least one electric motor upon impacting the corresponding obstacle is sensed and the gradient of this current signal is evaluated. Advantageously, a limit for detecting the squeeze condition is predetermined such that the gradient of the current signal sensed in the motor vehicle during adjustment lies within the limit. Advantageously, the limit can therefore be defined with high precision. Thus, the squeeze condition can be detected very reliably. Errors, especially the error of detecting a squeeze condition even when there is no squeeze condition, can be better avoided.

[0011] Additionally, a method for setting limits is advantageously provided for detecting compression during electromechanical adjustment of a steering column in a motor vehicle by means of at least one electric motor, according to the invention. In multiple adjustment operations, the steering column impacts an obstacle in each case during adjustment, wherein the obstacle simulates a possible real obstacle, and wherein a current signal generated by at least one electric motor of the steering column adjustment device upon impacting the corresponding obstacle is sensed and the gradient of the current signal is evaluated, and the limits are predetermined such that the gradient of the sensed current signal lies within the limits. Specifically, a gradient line generated by the gradient determined upon impacting a first obstacle is then advantageously defined as a lower limit, which is the least rigid of the other obstacles, wherein this lower limit can be further reduced, particularly by applying an offset to it. Another gradient line generated by the gradient determined upon impacting a second obstacle is then advantageously defined as an upper limit, which is the most rigid of the other obstacles, wherein the upper limit can be further increased, particularly by applying an offset to it. By testing other obstacles whose hardness is between that of the first and second obstacles, it is advantageous to check whether these obstacles are within the lower and upper limits, wherein, if necessary, the gradient lines forming the lower and upper limits are advantageously further adjusted so that the gradients produced by all other obstacles are within the lower and upper limits.

[0012] Furthermore, advantageously, obstacles are simulated separately by an arrangement comprising fixed spring elements and elastomeric elements facing the steering column. In this case, different obstacles are advantageously simulated by varying spring constants of the spring elements and / or varying Shore hardnesses of the elastomeric elements. Obstacles, especially parts of the human body, can be simulated to a near-perfect degree with minimal effort and low cost. Specifically, it is set here that the spring constant varies between 10 N / mm (N: Newton; mm: millimeter). The Shore hardness is advantageously varied between Shore A hardness 10 and Shore A hardness 70.

[0013] Specifically, a human finger is simulated using an arrangement of springs with a spring constant of 75 N / mm and elastomer elements with a Shore A hardness of 70. More specifically, a human knee is simulated using an arrangement of springs with a spring constant of 50 N / mm and elastomer elements with a Shore A hardness of 30. More specifically, a human abdomen is simulated using an arrangement of springs with a spring constant of 10 N / mm and elastomer elements with a Shore A hardness of 10. Advantageously, the gradient line generated in the case of an arrangement of springs with the highest spring constant and elastomer elements with the highest Shore hardness is limited to an upper limit. Advantageously, the gradient line generated in the case of an arrangement of springs with the lowest spring constant and elastomer elements with the lowest Shore hardness is limited to a lower limit. In this way, the detection of actual compression conditions can be further improved.

[0014] According to an advantageous improvement to the method for detecting squeezing conditions, gradient evaluation is performed within a defined adjustment range of the steering column. Specifically, it is configured that gradient evaluation is performed only within the adjustment range where squeezing conditions may occur. Advantageously, for this purpose, steering column position detection is used. Advantageously, errors related to detecting squeezing conditions can therefore be eliminated within these ranges. Advantageously, said range is adaptable, particularly depending on the position of the driver's seat.

[0015] In another advantageous improvement, the predetermined limit is adaptable through parameterization, particularly adaptable to different systems, wherein, in particular, at least one first parameter is provided to adapt to the gradient with respect to the lower limit and / or at least one second parameter is provided to adapt to the upper limit. Advantageously, the method is therefore better adapted to systems with different configurations, especially steering columns with different configurations.

[0016] According to another advantageous improvement, at least one predeterminable parameter is considered during the evaluation of the gradient of the current signal. Advantageously, the at least one predeterminable parameter includes at least one of the following parameters: a jitter elimination time, in particular a predetermined time, which defines how long the gradient of the sensed current signal must remain at least within the interval limit, and / or defines how long the gradient of the sensed current signal is allowed to exceed the limit; or the jitter elimination time and the result of the gradient counter. The gradient counter specifically has at least one of the following characteristics: if the jitter elimination time is not exceeded, the gradient counter is reset to zero (case 1); if the jitter elimination time is not exceeded, the gradient counter maintains its current value (case 2); if the jitter elimination time is not exceeded, the gradient counter decrements, in particular decrements to a value of zero (case 3). The above-described behavior of the gradient counter or variations between the three aforementioned cases are also specifically provided based on the time it takes for the gradient of the current signal to return to or have returned to the target range, i.e., the time it takes for the gradient of the current signal to remain within the predetermined limit. Specifically, according to an improved scheme, the gradient counter value is first held for a predetermined period of time (Case 2), for example, 50 ms (ms: milliseconds), and then advantageously reset to zero only (Case 1). During gradient evaluation, it can be specifically set that the counter must reach a predetermined value in order to detect squeezing conditions.

[0017] Because of the consideration of at least one parameter, it is advantageous to better prevent the actual extrusion result from being erroneously detected when it is at least partially outside the limit. Alternatively or additionally, the method can also provide filtering of the current signal before evaluating the current signal relative to the gradient, particularly to filter out unconsidered possible current fluctuations that may cause deviations from the predetermined limit, and thus improve the detection rate.

[0018] Furthermore, advantageously, at least one additional criterion is checked during steering column adjustment, wherein a squeeze condition is detected when at least one additional criterion is met. In this improved scheme, the gradient of the sensed current signal must advantageously be within predetermined limits and must additionally meet at least one criterion in order to detect a squeeze condition. The additional criterion may, in this case, be below the adjustment rate during the adjustment operation. More specifically, a deficiency in the speed conversion rate associated with the electric motor speed may be another criterion. Therefore, in particular, false detection of a squeeze condition can be prevented even better.

[0019] Specifically, it can be configured that upon detecting a compression condition, the steering column adjustment operation stops and is advantageously reversed. Therefore, in the event of a compression condition, the steering column is advantageously adjusted against the adjustment direction that caused the compression condition, particularly at a lower adjustment speed. Advantageously, this method can better prevent injury and / or damage.

[0020] An adjustable steering column for motor vehicles, proposed to address the aforementioned problem, comprises: a support unit through which an actuator is adjustablely held; and an adjustment device designed to adjust the actuator relative to the support unit, wherein the adjustment device for adjusting the actuator includes at least one electric motor, and wherein a control unit is provided for the steering column. In this case, the steering column is designed to perform the method according to the invention. Specifically, the control unit is designed in this case to actuate at least one electric motor to adjust the steering column, particularly relative to the support unit, wherein the control unit is also designed to sense a current signal for at least one electric motor during the adjustment operation and evaluate the gradient of the current signal, and to check whether the gradient of the current signal is within a predetermined limit during the evaluation of the gradient of the current signal. In this case, the control unit is also specifically designed to detect compression when the gradient of the current signal is within the predetermined limit. Attached Figure Description

[0021] Other advantageous details, features, and design details of the invention will be described in more detail with reference to the exemplary embodiments illustrated in the accompanying drawings, in which:

[0022] Figure 1 A first view of an exemplary embodiment of the steering column according to the present invention is shown in perspective.

[0023] Figure 2 A three-dimensional diagram is shown based on Figure 1 A second view of an exemplary implementation;

[0024] Figure 3 The sensed current signal, which has an indication limit within a defined adjustment range, is shown as a graph over time.

[0025] Figure 4 A simplified side view illustrates the structure of an exemplary embodiment used to determine the limits; and

[0026] Figure 5 A flowchart illustrating an exemplary embodiment of the method according to the present invention is shown. Detailed Implementation

[0027] In the various figures, the same parts are usually given the same reference numerals and are therefore explained in conjunction with only one figure in the figures.

[0028] Figure 1 An exemplary embodiment of the electromechanically adjustable steering column 1 according to the invention is shown in a schematic perspective view tilted from the upper left toward the rear end relative to the direction of travel of the vehicle (not shown), wherein the steering wheel (not shown here) remains within the operating range. Figure 2 The steering column 1 is shown in a view from the opposite side, i.e., from the upper right.

[0029] The steering column 1 includes a sheath unit 3 having an outer sheath tube 31, a middle sheath tube 32, and an inner sheath tube 33. The sheath tubes 31, 32, and 33 are arranged such that they can be axially and coaxially adjusted with each other in the axial direction of the longitudinal axis L, as indicated by the double arrow F.

[0030] Attached to the rear end of the outer sheath 31 is a stop 34, which protrudes inward at its open end into the intermediate space between the outer sheath 31 and the intermediate sheath 32. As the intermediate sheath 32 extends, it axially abuts against the stop 34 and is secured to prevent separation from the outer sheath 31. Attached to the rear end of the intermediate sheath 32 is a stop 35, which protrudes inward into the intermediate space between the intermediate sheath 32 and the inner sheath 33 and secures the inner sheath 33 to prevent it from being pulled out of the intermediate sheath 32.

[0031] Mounted in the sheath unit 3 is a steering spindle 37, which is rotatable about the longitudinal axis L and has a rear end for attaching a steering handle (in Figure 1 and Figure 2 (Not shown in the figure) Connection portion 38. Similar to the sheath unit 3, the steering spindle 37 is also designed to extend and retract in the longitudinal direction. The actuator 2 of the steering column 1 includes an inner sheath tube 33 and a steering spindle 37 mounted in the inner sheath tube 33. To achieve longitudinal adjustment relative to the sheath unit 3, the actuator 2 is received in the outer sheath tube 31 so that it can be moved in a telescoping manner in the direction of the longitudinal axis L, thereby positioning the steering wheel connected to the steering spindle 37 forward and backward relative to the support unit 4 in the longitudinal direction, as indicated by the double arrow F parallel to the longitudinal axis L.

[0032] The sheath unit 3 is held in a two-piece support unit 4, which has a fastening device 41 for attachment to a vehicle body (not shown).

[0033] The sheath unit 3 is mounted in its front region to allow it to pivot relative to the vehicle body about a schematically illustrated horizontal pivot axis S, which is transverse to the longitudinal axis L. For this purpose, a pivot support (not shown) is arranged in or between the support unit 4 and the vehicle body. In the rear region of the sheath unit 3, the sheath unit 3 is connected to the support unit 2 via an adjusting rod 42. Figure 2 As shown, by means of the rotational movement of the adjusting unit 6 of the adjusting device 7 of the steering column 1 via the adjusting rod 42, the sheath unit 3 can be adjusted, in particular, pivoted, relative to the support unit 4 about the horizontal pivot axis S in the installed state, together with the actuator 2. Thus, in particular, the steering handle attached to the fastening unit 38 can be adjusted in the vertical direction, as indicated by the double arrow H.

[0034] like Figure 1 As shown, another adjustment unit 5 of the steering column 1 adjustment device 7 is specifically designed for longitudinal adjustment of the actuator 2 relative to the sheath unit 3 and relative to the support unit 4 in the direction of the longitudinal axis L. In this exemplary embodiment, the other adjustment unit 5 has a spindle driver with a spindle nut 51 having an internal thread 74 extending along the spindle axis G, and a threaded spindle 52 engaging with the internal thread 74, i.e., the threaded spindle 52 is screwed into the corresponding internal thread 74 of the spindle nut 51 through its external thread. The threaded spindle axis of the threaded spindle 52 is the same as the spindle axis G in this exemplary embodiment and extends substantially parallel to the longitudinal axis L.

[0035] The spindle nut 51 is rotatably mounted in the support housing 53 about the spindle axis G, which is fixedly connected to the outer sleeve tube 31 of the sleeve unit 3. In the direction of the spindle axis G, the spindle nut 51 is axially supported on the sleeve unit 3 via the support housing 53. Therefore, in this exemplary embodiment, the adjusting device 5 is a so-called plunger-type spindle drive.

[0036] The threaded spindle 52 is connected at its free end to the inner sheath 33, so as to be supported on the arm 36 in a rotatable and axially fixed manner via fastening bolts 542, and the spindle nut 51 is axially, i.e., longitudinally, supported on the outer sheath 31 via the drive unit 53. The longitudinal direction corresponds to the direction of the longitudinal axis L. Due to the relative rotation of the electric motor 55 of the adjusting unit 5 by means of the adjusting device, the threaded spindle 52 and the spindle nut 51 move together or separately depending on the direction of rotation. As a result, the inner sheath 33 is axially retracted into or extends from the intermediate sheath 32, and the intermediate sheath 32 is retracted into or extends from the outer sheath 31, as indicated by the double arrows. Therefore, the steering wheel that can be attached to the connecting part 38 can be moved forward to the retracted position or the operating position. In the retracted position, the inner sheath 33 and the intermediate sheath 32 have been retracted into the outer sheath 31, i.e., sunk forward into the outer sheath 31. In the operating position, the sheaths 31, 32 and 33 have extended outwards from each other in a nested telescoping manner.

[0037] In showing from Figure 1 A three-dimensional view of the steering column 1 viewed from the rear. Figure 2 Clearly, it is evident how the adjustment unit 6 of the adjustment device 7, used for vertical adjustment, is attached to the steering column 1. The adjustment unit 6 of the adjustment device 7 is configured in principle to operate in the same manner as the other adjustment unit 5 of the adjustment device 7. The adjustment unit 6 also includes a spindle nut 61, wherein the internal thread of the spindle nut 61 engages with a threaded spindle 62 along the spindle axis G. The threaded spindle 62 is mounted in a support housing 63, which is fastened to a sheath unit 3 so that it can rotate about the axis G and be axially supported on the sheath unit 3 in the direction of the axis G, and can be driven by an electric motor 65 to selectively rotate in two rotational directions about the axis G.

[0038] In the illustrated embodiment, the adjusting units 5 and 6 of the adjusting device 7 of the steering column 1 are so-called plunger-type spindle drives. Alternatively, a rotary spindle drive may also be specifically formed, in which the spindle nut 51 is rotatably held on the steering column 1 and the threaded spindle 52 can be driven to rotate by the motor 55.

[0039] The adjustment unit 6 acts on the end of the double-arm adjustment rod 42, which is mounted on the support unit 4 so that it can rotate about the pivot support 43, and the other arm of the double-arm adjustment rod 42 is connected to the sheath unit 3 at the other end of another pivot support 44.

[0040] The steering column 1 also includes a control unit 8, which is only used in... Figure 1 and Figure 2 The diagram is schematically illustrated. In this case, the control unit 8 is designed to perform a method for detecting a squeeze condition during the adjustment of the steering column 1 by means of at least one electric motor 55, 65 in a motor vehicle, i.e., during the adjustment of the actuator 2 relative to the support unit 4 in this case. In this case, the adjustment of the steering column 1 specifically refers to the adjustment between the retracted position and the operating position, i.e., the adjustment from the retracted position to the operating position or from the operating position to the retracted position. The control unit 8 is designed to sense a current signal for at least one electric motor 55, 65 during the adjustment operation, to evaluate the gradient of the current signal, and to check whether the gradient of the current signal is within a predetermined limit during the evaluation of the gradient of the current signal, wherein a squeeze condition is detected when the gradient of the current signal is within the predetermined limit.

[0041] Figure 3 The graph illustrates, for example, the lines representing the first current signal C1 generated by the electric motor 55 during a first adjustment operation of the steering column 1 and the second current signal C2 generated by the electric motor 55 during a second adjustment operation of the steering column 1. In this graph, time (t) in seconds (s) is plotted on the x-axis, and the y-axis indicates current (I) in amperes (A). In this case, for both adjustment operations, a compression occurs, resulting in a significant increase in both the first current signal C1 and the second current signal C2 within the range AoI.

[0042] Here, the range AoI corresponds to the previously defined adjustment range of the steering column 1, within which squeezing is entirely possible. Within the range AoI, during adjustment operations, current signals C1 and C2 are sensed for the electric motor 55, and the gradients of the corresponding current signals C1 and C2 during the corresponding adjustment operations are evaluated. During the evaluation of the gradients of the current signals C1 and C2, it is checked whether the gradients of the current signals C1 and C2 are within predetermined limits Th1 and Th2, wherein squeezing is detected when the gradients of the current signals C1 and C2 are within the predetermined limits Th1 and Th2. In this exemplary embodiment, the limits Th1 and Th2 are defined by a predetermined first gradient line forming the upper limit Th1 and a predetermined second gradient line forming the lower limit Th2. In this case, the first gradient line is a portion of a first gradient straight line, which has been determined in a test series, as will be referred to below. Figure 4 A more detailed explanation follows. The second gradient line is a portion of the second gradient line, which is also specifically determined in the test series. Figure 3 Another gradient line D is shown, which is also specifically determined in the test series and lies within the limits Th1 and Th2. (See from...) Figure 3It is obvious that the gradient of the first gradient line, i.e. the upper limit Th1, is greater than the gradient of the second gradient line, i.e. the lower limit Th2.

[0043] like Figure 3 As illustrated, a squeezing condition is detected if the gradients of the sensed current signals C1 and C2 are now within the evaluation range defined by a predetermined adjustment range AoI, i.e., between the lower limit Th2 and the upper limit Th1. Conversely, if the gradients of the sensed current signals remain below the lower limit Th2 or above the upper limit Th1, a squeezing condition is not detected. The predetermined parameters define how to avoid momentarily falling below and / or exceeding one of the limits Th1 and Th2. For example, Figure 3 The diagram illustrates that the current signal C1 briefly falls below the lower limit Th2, i.e., C1E. This deficiency does not affect the detection of compression conditions.

[0044] also, Figure 3 A current spike P2 is shown, for example, in the sensed current signal C2. Since this current spike P2 occurs outside the previously defined adjustment range AoI in which only the current signal C2 is evaluated, the current signal C2 is not evaluated when the current spike P2 occurs, and since the current spike P2 in this exemplary embodiment is purely attributable to mechanical reasons during the adjustment of the steering column 1, false detection of a squeeze condition is avoided.

[0045] Figure 4 The test apparatus 100 is illustrated by way of example, and this test apparatus 100 can be used to perform actions such as setting... Figure 3 The method shown, with limits Th1 and Th2, is used to detect compression during adjustment of the steering column 1. In this case, the test apparatus includes an adjustable steering column 1 with a steering wheel 9, wherein the steering column 1 and its support unit are fixedly arranged in arrangement position 110. A support structure 115 with a retaining element 116 is also arranged in arrangement position 110. A spring element 101 and an elastomer element 102 are arranged on the retaining element 116 in the form of arrangement structure 103 to simulate obstacles that the steering wheel 9 may hit during adjustment of the steering column 1. The adjustability of the steering column 1 in the longitudinal direction... Figure 4 The symbolic map is represented by a double arrow F. The support structure 115 and the retaining element 116 are formed in a rigid manner in this case, such that their characteristics have a negligible effect when the steering wheel 9 impacts the arrangement structure 103.

[0046] In multiple adjustment operations of the steering column 1, the steering column 1 is struck by the arrangement structure 103, which acts as an obstacle, with the steering wheel 9 during the adjustment. When the arrangement structure 103 is struck, a current signal generated by at least one electric motor of the steering column 1's adjustment device is sensed by means of a control unit 8 assigned to the steering column 1, and the gradient of the current signal is evaluated. In this case, the limit for detecting the compression condition is predetermined and adjusted as needed, such that the gradient of the sensed current signal is within the limit.

[0047] Different obstacles can be simulated using the arrangement structure 103 by varying the stiffness of the elastomer element 102 and the spring element 101 to have different spring constants. Thus, the arrangement structure 103, consisting of a spring element 101 with a spring constant of 75 N / mm and an elastomer element 102 with a Shore A stiffness of 70, simulates a crushed human finger as an obstacle. The arrangement structure 103, consisting of a spring element 101 with a spring constant of 50 N / mm and an elastomer element 102 with a Shore A stiffness of 30, simulates a crushed human knee as an obstacle. The arrangement structure, consisting of a spring element 101 with a spring constant of 10 N / mm and an elastomer element 102 with a Shore A stiffness of 10, simulates a crushed human abdomen as an obstacle. Other combinations and other spring elements 101 and other elastomer elements 102 can be used for further simulations.

[0048] In this case, the current signal generated when the steering wheel 9 impacts the critical compression condition but is the most elastic arrangement 103 compared to the other arrangement 103 used is evaluated with respect to its gradient. The gradient line generated by the determined gradient is defined as a lower limit Th2. Then, the gradient line generated in a corresponding manner when impacting another arrangement 103 that is the stiffest compared to the other arrangement 103 is defined as an upper limit Th1. By testing with other arrangement 103s used that have a stiffness between the defined limits Th2 and Th1, it is then checked whether the gradient of the current signal is within the lower limit Th2 and the upper limit Th1. If necessary, the gradient lines forming the lower limit Th2 and the upper limit Th1 are readjusted so that all gradients determined or already determined when the steering wheel 9 impacts all other arrangement 103s are within the lower limit Th2 and the upper limit Th1.

[0049] pass Figure 5The flowchart illustrated in the figure describes another exemplary embodiment of the method for detecting a squeeze condition according to the present invention. In this case, the electromechanical adjustment operation of the steering column begins, wherein, in step 200, the position of the steering column or the position of the steering column actuator is sensed. In another step 210, it is checked whether the position is within a predetermined adjustment range (Y) in which a squeeze condition may occur, or not within the predetermined adjustment range (N). If the detected position is not within the predetermined adjustment range (N), initially nothing further happens; however, during further adjustment, the position continues to be sensed (step 200), and it is checked whether the position is within the predetermined adjustment range.

[0050] If the position is within a predetermined adjustment range (Y), then in step 300, a current signal is sensed for the electric motor operated for adjustment. In another step 310, the gradient of the sensed current signal is evaluated, and in step 320, it is checked whether the gradient of the current signal is within a predetermined limit. If this is not the case (N), the adjustment operation continues normally, and the steps for detecting compression continue. Conversely, if the gradient of the sensed current signal is within the predetermined limit (Y), compression is detected in step 330.

[0051] Then, in another step 340, the adjustment operation is stopped, and in step 350, the actuator moves in the opposite direction to the original adjustment direction, specifically by a predetermined adjustment stroke in the opposite direction to the original adjustment direction.

[0052] Figure 5 A variation of the implementation, including additional steps 400 and 410, is also illustrated. This can be optionally provided. In this variation, after the check in step 320, a gradient of the current signal has been detected to be within a predetermined limit (Y), and another parameter is detected in step 400. In step 410, as another criterion during steering column adjustment, it is checked whether the sensed parameter meets the criterion. If the parameter does not meet the criterion (N), the adjustment operation continues, and it is further checked whether it is related to the presence of a squeeze condition. However, if the parameter meets the criterion (Y), a squeeze condition is detected in step 330, and then the other steps 340 and 350 are performed as described above.

[0053] The exemplary embodiments shown in and explained in conjunction with the accompanying drawings are used to explain the present invention and are not intended to limit the invention.

[0054] List of reference numerals

[0055] 1. Steering column

[0056] 2 Actuators

[0057] 3 Sheath Units

[0058] 31 Outer sheath

[0059] 32 Intermediate sheath tube

[0060] 33 Inner sheath

[0061] 34, 35 stop parts

[0062] 36 arms

[0063] 37 Steering spindle

[0064] 38 Connection Part

[0065] 4 Support Units

[0066] 41 Fastening device

[0067] 42 Adjusting rod

[0068] 43, 44 Pivot Supports

[0069] Adjustment units 5 and 6

[0070] 51, 61 spindle nuts

[0071] 52 and 62 threaded spindles

[0072] 53, 63 Support Component Housing

[0073] 542 fastening bolts

[0074] 55 and 65 electric motors

[0075] 7. Adjustment device

[0076] 8 Control Unit

[0077] 9. Steering wheel

[0078] 100 Test Device

[0079] 101 Spring Component

[0080] 102 Elastomer Components

[0081] 103 Layout Structure

[0082] 110 Location

[0083] 115 Support Structure

[0084] 116 Holding element

[0085] L longitudinal axis

[0086] S Pivot axis

[0087] G. Spindle axis (threaded spindle axis)

[0088] F is a double arrow used to symbolically illustrate vertical adjustability.

[0089] The H symbolically represents a double arrow representing vertical adjustability.

[0090] The adjustment range defined by AoI assessment

[0091] D gradient line

[0092] C1 current signal

[0093] C1E is below the lower limit (Th2).

[0094] C2 current signal

[0095] P2 current spike

[0096] Th1 upper limit

[0097] Th2 lower limit

[0098] 200 to 410 method steps

[0099] N test conditions were not met.

[0100] The Y test condition is met.

Claims

1. A method for detecting compression during electromechanical adjustment of a steering column (1) in a motor vehicle by means of at least one electric motor (55, 65), wherein, During the adjustment operation, a current signal (C1) is sensed for the at least one electric motor (55, 65) and the gradient of the current signal (C1) is evaluated. The method is characterized in that, during the evaluation of the gradient of the current signal (C1), it is checked whether the gradient of the current signal (C1) is within a predetermined limit (Th1, Th2), wherein when the gradient of the current signal (C1) is within the predetermined limit (Th1, Th2), a squeezing condition is detected.

2. The method according to claim 1, characterized in that, The limits (Th1, Th2) are predetermined by a first gradient line that forms the upper limit (Th1) and a second gradient line that forms the lower limit (Th2).

3. The method according to claim 2, characterized in that, The first gradient line is a part of a first gradient curve, and the second gradient line is a part of a second gradient curve, wherein the gradient of the first gradient line is greater than the gradient of the second gradient line.

4. The method according to any one of the preceding claims, characterized in that, The limits (Th1, Th2) are predetermined, wherein, in multiple adjustment operations, the steering column (1) strikes an obstacle in each case during adjustment, wherein the obstacle simulates a possible real obstacle, and wherein a current signal (C1) generated by the at least one electric motor (55, 65) upon striking the corresponding obstacle is sensed and the gradient of the current signal (C1) is evaluated, and the limits (Th1, Th2) are predetermined such that the gradient of the sensed current signal (C1) lies within the limits (Th1, Th2).

5. The method according to claim 4, characterized in that, The obstacles are simulated by an arrangement structure (103) comprising a fixedly arranged spring element (101) and an elastomer element (102) facing the steering column (1), wherein different obstacles are simulated by different spring constants of the spring element (101) and / or different Shore hardnesses of the elastomer element (102).

6. The method according to claim 5, characterized in that, The spring constant varies between 10 N / mm and 75 N / mm, and / or the Shore hardness varies between Shore A hardness 10 and Shore A hardness 70.

7. The method according to any one of the preceding claims, characterized in that, The evaluation of the gradient of the current signal (C1) is performed within the defined adjustment range (AoI) of the steering column (1).

8. The method according to any one of the preceding claims, characterized in that, The predetermined limits (Th1, Th2) are adaptable through parameterization.

9. The method according to any one of the preceding claims, characterized in that, During the evaluation of the gradient of the current signal (C1), at least one predefined parameter is considered, wherein the at least one predefined parameter includes at least one of the following parameters: jitter elimination time; or jitter elimination time and the result of the gradient counter.

10. The method according to any one of the preceding claims, characterized in that, During the adjustment of the steering column (1), at least one other criterion (410) is additionally checked, wherein a squeeze condition (330) is detected when the at least one other criterion (410Y) has been additionally met.

11. The method according to any one of the preceding claims, characterized in that, After the compression condition is detected (330), the adjustment operation stops (340) and reverses (350).

12. An adjustable steering column (1) for use in a motor vehicle, the steering column (1) comprising: The actuator (2) is held in an adjustable manner by the support unit (4); and an adjustment device (7) designed to adjust the actuator (2) relative to the support unit (4), wherein the adjustment device (7) for adjusting the actuator (2) includes at least one electric motor (55, 65), and the steering column (1) is provided with a control unit (8), characterized in that the steering column (1) is designed to perform the method according to any one of the preceding claims.

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