Adjustment device for head rest of motor vehicle seat

The present invention relates to a vehicle seat headrest position adjusting device.

Headrests in vehicle (automobile) seats are used to support the heads of seated occupants in the event of a collision and prevent the cervical spine from bending backwards. However, the safety achieved with the headrest is only achieved when the headrest is placed at an appropriate height with respect to the vertical head position and the head hits the headrest center essentially intended for it in the event of a collision. On the other hand, if the headrest is placed in an inappropriate position, the neck and head parts will be injured in the event of a collision. The headrest should be placed as close as possible to the occupant's head, even horizontally, to minimize the risk of head injury, such as concussion, when the head hits the headrest. Must be able to move without hindrance.

In order to properly position the headrest, the headrest is generally adjustable vertically as well as partially horizontally with respect to the seat back. In the case of headrests for luxury cars, the position of the headrests is usually adjusted automatically.

In order to prevent mispositioning of the headrest, a detection device for detecting the position of the occupant's head with respect to the headrest is sometimes attached to the recent headrest position adjusting device. That is, for example, the headrest position adjusting device known in Patent Document 1 is provided with a detection device in the form of a capacitive proximity sensor incorporated in the headrest. The proximity sensor has three electrodes vertically spaced apart from each other on the front surface of the headrest. Both the upper and lower electrodes are used as transmission electrodes to radiate an alternating electric field in the spatial range existing in front of the headrest. The intermediate electrode is used as a joint receiving electrode to measure the capacitance (capacitance) formed between the receiving electrode and each transmitting electrode. This known position adjusting device utilizes the physical effect that the capacitance of the electrode device changes characteristically due to the presence of the head in the alternating electric field. The deviation of the headrest position from the vertical target position of the headrest preset with respect to the occupant's head is detected by comparing the capacitance values associated with both transmitting electrodes. The headrest position where both capacitance values are the same is identified as the target position of the headrest.

Further, similar headrest position adjusting devices having a capacitive proximity sensor having three electrodes each are also known in Patent Document 2 and Patent Document 3.

<p><patcit num="1"><text>European Patent Application Publication No. 1857318</text></patcit><patcit num="2"><text>French Patent Application Publication No. 2884775</text></patcit><patcit num="3"><text>German Patent No. 19916804</text></patcit><patcit num="4"><text>European Patent Application Publication No. 1957318</text></patcit></p>

<p> An object of the present invention is to provide an improved headrest position adjusting device as compared with a conventionally known headrest position adjusting device.</p>

<p> This problem is solved by the feature described in claim 1 in the first aspect of the invention. Accordingly, the headrest position adjusting device according to the present invention has a capacitive proximity sensor incorporated in the headrest or designed to be incorporated into the headrest, and the proximity sensors are vertically spaced apart from each other. It has at least three transmitting electrodes and one joint receiving electrode. Here, the term "vertical" refers to a direction determined according to the assembled state according to the intended use of the proximity sensor in an automobile.</p><p> Further, this position adjusting device operates the elevating actuator for automatically adjusting the position of the headrest in the vertical direction with respect to the vehicle seat and the elevating actuator according to the head position detected by the proximity sensor of the occupant seated on the vehicle seat. Has a control device for. This controller is configured to perform the following control operations (circuit technically and / or programmatically). That is, in this control operation, the transmitting electrode is operated to transmit an alternating electric field, and from the electric reception signal detected by the receiving electrode, information about the capacitance formed between each transmitting electrode and the receiving electrode is obtained. Each associated capacitance measurement, including, is determined, and depending on the capacitance measurement, the elevating actuator is operated to position the headrest in the vertical target position with respect to the occupant's head position.</p><p> The above-mentioned problem is also solved by the feature described in claim 3 in the second aspect of the invention. The headrest position adjusting device designed accordingly corresponds essentially to the first aspect of the invention described above. However, the proximity sensor according to the second aspect of the invention has at least three receiving electrodes vertically spaced apart from each other instead of at least three transmitting electrodes. According to the second aspect of the invention, a joint transmitting electrode is provided instead of the joint receiving electrode.</p><p> In both forms of the invention described above, the underlying physical principles and the actions aimed at based on the present invention are essentially the same. In particular, the replacement of the transmit and receive electrodes does not affect the characteristics of the alternating electric field propagating based on the proximity sensor in the spatial range in front of the headrest (ignoring sign inversion).</p>

<p> The electrode device based on the present invention of the proximity sensor ensures that headrest mispositioning on the system, which cannot be eliminated by known position adjusting devices, is prevented. That is, by comparing the capacitances formed between the electrodes in a proximity sensor that has only three electrodes, the human body part of the occupant whose distance to the electrode device is an extreme value (that is, a minimum value or a maximum value). On the other hand, the electrode device based on the present invention can assistly detect whether or not the human body portion of the occupant located facing the proximity sensor is curved in a convex or concave shape. This is also the desired target position where the center of the headrest is located approximately at the height of the occupant's (convex curved) head and the headrest is approximately flush with the occupant's (concavely curved) neck. Allows a clear distinction from unwanted headrest positions placed on the.</p><p> In an advantageous embodiment (in the first embodiment of the invention) of the present invention, at least three transmitting electrodes are actuated sequentially in time, i.e. according to time division multiplication. Thereby, the total received signal received by the joint receiving electrode is decomposed into the individually received signals which are well separated in time and are related to the predetermined transmitting electrodes. From each of these individual received signals, the capacitance formed between the receiving electrode and its associated transmitting electrode can be calculated particularly easily. In the case of the second aspect of the invention, there is only one transmitting electrode pulsed to radiate an alternating electric field continuously or periodically for the purpose. In this case, a separate reception signal is supplied to the control device from at least three individual reception electrodes, and the capacitance formed between the related reception electrode and the joint transmission electrode can be calculated from the reception signal. Each of these receiving electrodes is read at the same time, especially in time. However, in order to simplify the reading circuit provided to the control device, the receiving electrodes can be made to be read sequentially in time.</p><p> A plurality of developed forms for simplifying the first aspect of the invention will be described in detail below. However, these developed forms can also be diverted to the second aspect of the invention within the framework of the present invention, in which case the advantages described below can also be realized. In the diversion to the second aspect of the invention, the terms "transmitting electrode" and "receiving electrode" in the following description are semantically replaced.</p><p> In order to evaluate the received signal numerically and particularly simply, the electrodes of the proximity sensor according to the present invention are preferably arranged three-dimensionally with each other so that all the transmitting electrodes have the same spacing with respect to the joint receiving electrode. ing. This is achieved in a particularly purposeful manner by forming the joint receiving electrode with one vertically elongated electrode region extending over the vertical range of the headrest surface occupied by at least almost all transmitting electrodes. However, optionally, the joint receiving electrodes can also have a plurality of electrode regions short-circuited with each other.</p><p> In this case, the electrode region of the joint receiving electrode or each electrode region is placed outside the at least three transmitting electrodes. However, in order to obtain a particularly large sensor effective range, at least each of the three transmitting electrodes is divided into two electrode regions that are placed at the same vertical height and are horizontally spaced apart from each other, and between the two electrode regions. A sensor device with an extended joint receiving electrode (especially near its center) is particularly advantageous. This sensor device is considered an independent invention (regardless of other features of the headrest position adjuster).</p><p> In order to be able to determine the target position of the headrest particularly simply and accurately based on the received signal, at least two transmitting electrodes are arranged symmetrically with respect to the center of the headrest in the vertical direction, that is, for the purpose. , Located above or below the headrest. In order to recognize the arrival of the vertical target position within the framework of the control operation assigned to the control device, the capacitance measurement associated with those transmitting electrodes and at least another capacitance measurement are comparatively evaluated.</p><p> In this case, the center of the headrest is at the extreme distance to the occupant, that is, the minimum or maximum distance by comparing the capacitance measurements of both transmitting electrodes arranged symmetrically by the control device according to the purpose. The headrest position is recognized when the values of both capacitance measurements at the time of reaching the headrest position intersect, that is, they are the same value. The purpose is whether the distance between the occupant formed at this headrest position and the center of the headrest is the minimum or maximum, that is, whether the human body portion located facing the proximity sensor is a convex surface or a concave surface. Appropriately, it is recognized by the value of the third capacitance measurement relative to the value of the intersecting capacitance measurement. In that case, the headrest position is recognized as the target position only when the distance between the occupant and the center of the headrest is evaluated to be the minimum at the headrest position.</p><p> In order to move the headrest to the target position quickly but accurately without the headrest passing too far through the target position, the displacement movement speed of the actuator is based on the capacitance measurement within the framework of the control method implemented in the control device. Especially, it is lowered continuously or in several steps before reaching the target position.</p><p> In the first embodiment of this control mode of operation, the proximity sensors have three or more particularly five transmit electrodes arranged vertically spaced apart from each other. In this case, the control device reduces the moving speed of the actuator by a predetermined value when the measured capacitances of the two adjacent transmitting electrodes intersect in value.</p><p> Alternatively or additionally, in connection with the control operation by the controller, the capacitance measurement of at least one of the three transmitting electrodes exceeds the extremum, i.e. the minimum or maximum. When, it is designed to reduce the moving speed of the actuator.</p><p> In an advantageous embodiment of the control operation imparted to the controller, the controller first inspects whether the occupant's head is primarily within the detection range of the proximity sensor. To this end, for example, the controller performs a so-called search, in which at least one capacitance measurement, preferably the total capacitance measurement, is present within the detection range of the proximity sensor during vertical movement of the headrest. Is repeatedly compared continuously or periodically with the stored threshold value. Instead, a change in one or more capacitance measurements is detected over the displacement movement stroke of the headrest, from which the presence or absence of an occupant in the detection range of the proximity sensor is inferred. In response to the control operation, the control device displacements and adjusts the headrest to the stored standard target position whenever the head position is not detected in the entire position adjustment range of the headrest. This standard target position is, in particular, the so-called 2/3 position where the headrest is extended upward by about 2/3 of its entire vertical movement stroke. This 2/3 position is known to be the best headrest adjustment position for a standard physique occupant. Therefore, at that 2/3 position, at least an acceptable protective effect is achieved for a normal occupant, even if the headrest height is not adjusted to that occupant's own position. Position adjustment to 2/3 position according to this paragraph in the case of false detection of head position is basically considered an independent invention without any other features of the position adjustment device.</p><p> The headrest is, in particular, a four-way movable headrest that is vertically and horizontally adjustable, i.e. up and down and back and forth. Here, the terms "vertical" and "horizontal" mean the approximate direction of the headrest with respect to the adjusting direction. In particular, the vertical position adjustment direction of the headrest extends substantially parallel to the longitudinal direction of the seat back of the vehicle seat, and is therefore slightly inclined with respect to the vertical line of the surrounding space. The horizontal position adjustment direction of the headrest extends substantially at right angles to the vertical position adjustment direction in particular, and is therefore also somewhat inclined with respect to the horizontal direction of the surrounding space. Further, the horizontal position adjustment direction and the vertical position adjustment direction form an angle slightly deviated from 90 °. The degree of freedom in adjusting the horizontal position of the headrest is also formed by the inclination of the headrest about the horizontal axis.</p><p> In order to control the quadruple movable headrest, the position adjusting device also has, in particular, a front-rear actuator that horizontally displaces the headrest, that is, the front of the headrest facing the seated occupant as intended for use. Within the framework of the control operation assigned to the control device, the front and rear actuators are operated to adjust the displacement of the headrest to the horizontal target position, particularly after reaching the vertical target position of the headrest. In this case, the horizontal target position is determined by comparing at least one capacitance measurement with a stored threshold. To that end, the control device is particularly concerned with capacitance measurements associated with intermediate transmit or receive electrodes located approximately centered on the headrest.</p><p> Capacitance measurements of capacitive proximity sensors also cognitively represent system dependence, i.e., some dependence on the horizontal position of the headrest in the absence of an occupant. The cause of this system dependency is especially the metal parts of the headrest. Such metal parts form a sham capacitance with the electrodes of the proximity sensor, and the magnitude of the sham capacitance varies due to the distance that changes with respect to the electrodes of the proximity sensor as the headrest moves horizontally.</p><p> A metal specifically grounded behind the electrodes of the proximity sensor (as already known in Patent Document 4) within the framework of the proximity sensor according to the invention to eliminate or at least reduce the amount of disturbance. A shield is provided. However, as a result of experiments, it has been confirmed that the shield unfavorably limits the detection effective range of the proximity sensor.</p><p> Therefore, preferably, the capacitance measurement amount or each capacitance measurement amount involved in adjusting the displacement to the horizontal target position is numerically compensated. To that end, the above-mentioned capacitance measurements are standardized by the controller, in particular, to a memorized system characteristic curve that represents the system-dependent course of capacitance measurements related to the horizontal position of the headrest, that is, the course that is unaffected by the occupants. ing.</p><p> In order to move the headrest to the horizontal target position quickly and accurately, in an embodiment suitable for the purpose of the control operation, the displacement movement speed of the front-rear actuator is continuously controlled by the control device while approaching the horizontal target position. Alternatively, it is lowered in several steps. In that case, the controller controls the displacement movement speed, especially based on the comparison of the capacitance measurement quantity with multiple graduated thresholds, in which case the displacement movement speed of the front-rear actuator is determined by the capacitance measurement quantity. It is reduced each time the threshold is exceeded, thus discontinuously decreasing in several steps.</p><p> All of the above-mentioned control operation schemes of the present invention are considered to be independent inventions in their own right, particularly independent of automatic implementation by the control device.</p><p> Examples of the present invention will be described in detail with reference to the following figures. In each figure, the same part and the same unit amount are designated by the same reference numerals.</p>

<figref num="1">Schematic cross-sectional view of the headrest with a position adjuster having a capacitive proximity sensor, a control device, an elevating actuator for adjusting the vertical position of the headrest, and a front-rear actuator for adjusting the horizontal position of the headrest and the head of the occupant. Schematic side view of.</figref><figref num="2">FIG. 6 is a schematic block diagram of a first embodiment of the position adjusting device in FIG.</figref><figref num="3">The schematic block diagram of the control device in the position adjustment device of FIG.</figref><figref num="4">A diagram of the progress of the five capacitance measurements of the proximity sensor with respect to the vertical position of the headrest (upper diagram) and the transition of the displacement movement speed of the elevating actuator adjusted by the control device in relation to this measurement (lower diagram). ..</figref><figref num="5">A schematic side view of the occupant's head and headrests placed at head height, and a schematic bar graph comparing the respective values of the capacitance measurements obtained at this position.</figref><figref num="6">A schematic side view of the head and here the headrest placed at neck height and a schematic bar graph corresponding to FIG. 5 comparing the respective values of the capacitance measurements obtained at this position.</figref><figref num="7">The progress of the capacitance measurement amount when the head is present with respect to the headrest horizontal position, the corresponding system characteristic curve (upper diagram) of the capacitance measurement amount at the headrest horizontal position, and the system of the capacitance measurement amount when the head is present. A diagram of the process standardized to the characteristic curve (center diagram) and the process of displacement movement speed of the front-rear actuator adjusted in relation to this standardized capacitance measurement (bottom diagram).</figref><figref num="8">The figure corresponding to FIG. 2 of the 2nd Example of the position adjustment device.</figref><figref num="9">The figure corresponding to FIG. 3 of the control device in the position adjustment device of FIG.</figref><figref num="10">Schematic of different embodiments of proximity sensors.</figref><figref num="11">Schematic of a further different embodiment of the proximity sensor.</figref><figref num="12">Schematic of a further different embodiment of the proximity sensor.</figref>

FIG. 1 schematically shows a seat (for a vehicle), in which only the upper part of the seat back 2 is shown. Further, FIG. 1 shows a headrest 3 with respect to the head 4 of the occupant 5 seated on the seat 1, and the headrest 3 is attached to the seat back 2. The seat 1 is especially the driver's seat or the passenger seat of a passenger car.

The headrest 3 is a so-called four-way movable headrest, and its displacement can be adjusted in the vertical (vertical) direction 6 and the horizontal (front-back) direction 7 with respect to the seat 1. Here, the terms "vertical" and "horizontal" are "rough" orientation designations that specify an approximate adjustment direction. In particular, the vertical direction 6 extends substantially parallel to the longitudinal direction of the seat back 2 and is slightly inclined with respect to the space perpendicular line. The horizontal direction 7 extends substantially at right angles to the vertical direction 6, and extends substantially parallel to the longitudinal direction of the vehicle in the assembled state of the headrest 3. In the following, the vertical direction 6 is referred to as upward, and the horizontal direction 7 is referred to as forward, in which case the terms "up", "down", "front", and "rear" are assembled according to the intended use of the headrest 3 in the automobile. Is related to. Correspondingly, the side of the headrest 3 facing the side of the head 4 of the occupant 5 is called the front or the front.

The headrest 3 has a substantially shell-shaped back component 8 made of metal and / or loadable plastic and a front component 9 held within the back component 8. Support rods (headrest stays) 10 extending in the vertical direction 6 are provided on both sides of the lower end of the back component 8, and the headrest 3 is fastened to the seat back 2 by the support rods 10 in the usual manner. The headrest 3 is guided by a support rod 10 so as to be movable in the vertical direction 6 to the headrest holder 11 of the seat back 2.

The front component 9 of the headrest 3 has a support shell 13 specifically made of loadable plastic. A cushion 14 is attached to the front surface of the support shell 13. Further, the cushion 14 is covered with a cover 15 made of a fiber material or leather that forms an outer cover of the front surface of the headrest 3.

The front part 9 of the headrest 3 is guided in the back part 8 so as to be movable in the horizontal direction 7 along the surrounding wall. The guide is formed of, for example, a rack 16 fixed to the front component 9 and extending in the holder 17 of the rear component 8.

FIG. 1 shows the headrest 3 in which the vertical displacement distance V is at the maximum value and the horizontal displacement distance H is at the minimum value. On the contrary, the position of the back component 8 where the vertical displacement distance V is the minimum value and the position of the front component 9 where the horizontal displacement distance H is the maximum value are shown by broken lines in FIG. The headrest position can be continuously adjusted within the range up to the maximum vertical displacement distance V and the maximum horizontal displacement distance H.

A position adjusting device 20 is attached to the headrest 3 in order to adjust the displacement of the headrest 3. The position adjusting device 20 includes a capacitive proximity sensor 21, a (vertical) elevating actuator 22 for vertically displacing the headrest 3, a (horizontal) front-rear actuator 23 for horizontally displacing the headrest 3, and a control device 24. Have.

The proximity sensor 21 is arranged inside the headrest 3 between the support shell 13 and the cushion 14. However, the proximity sensor 21 can also be placed between the cushion 14 and the cover 15, and therefore just inside the front of the headrest 3.

The elevating actuator 22 is arranged inside the seat back 2 and acts on the support rod 10 of the headrest 3 as known. The front and rear actuators 23 are located inside the headrest 3 and cooperate with the rack 16 to displace the front component 9 with respect to the rear component 8.

In particular, the control device 24 similarly arranged in the headrest 3 is connected to the proximity sensor 21, the elevating actuator 22, or the front-rear actuator 23 via the data wirings 25, 26, and 27. The data wiring 26 is led from the headrest 3 to the seat back 2 through one support rod 10. Further, a feeder line (not shown) for supplying power to the front-rear actuator 23 and the control device 24 is guided through one support rod 10.

<p> FIG. 2 shows in detail the first embodiment of the position adjusting device 20. As can be seen from FIG. 2 in combination with FIG. 1, the proximity sensor 21 has a flat substrate 30. An electrode device formed of five transmitting electrodes 31a to 31e and one joint receiving electrode 32 is provided on the substrate 30. The substrate 30 is particularly made of a flexible synthetic resin film. The transmitting electrodes 31a to 31e and the receiving electrodes 32 are also particularly formed of a flexible synthetic resin film and are attached to, for example, the substrate 30. Instead, the transmitting electrodes 31a to 31e and the receiving electrodes 32 can be provided on the substrate 30 in the form of a coating.</p><p> The substrate 30 extends vertically 6 over the main plane portion of the headrest 3 and in the vehicle lateral direction 33 perpendicular to it. In particular, the substrate 30 is arranged so as to be substantially centered on the center 34 of the headrest 3 where the head 4 collides with the head rest 4 as intended in the event of a collision.</p><p> Further, the transmitting electrodes 31a to 31e and the receiving electrodes 32 are distributed and arranged over most of the plane of the substrate 30. In this case, the receiving electrode 32 is formed by an electrode region 35 in the form of an elongated strap. This electrode region 35 is centrally located on the substrate 30 in the vehicle lateral direction 33 and extends in the vertical direction 6 over the entire height range occupied by the transmitting electrodes 31a to 31e. Each of the transmitting electrodes 31a to 31e is divided into two electrode regions 36 and 37 short-circuited with each other, and the electrode regions 36 and 37 of the same transmitting electrodes 31a to 31e are the receiving electrodes at the same vertical height and in the vehicle lateral direction 33, respectively. It extends to the left or right side of 32. The electrode regions 36 and 37 of the different transmission electrodes 31a to 31e are arranged vertically spaced apart from each other. In this case, the electrode regions 36 and 37 of the transmission electrode 31a are arranged at the lowest position, and the electrode regions 36 and 37 of the transmission electrode 31e are arranged at the uppermost position. The transmitting electrode 31c is arranged so as to be substantially centered on the center 34 in the vertical direction. The same vertical spacing is formed between adjacent transmission electrodes 31a, 31b; 31b, 31c; 31c, 31d; 31d, and 31e, respectively. Further, the entire electrode regions 36 and 37 of the different transmitting electrodes 31a to 31e exist at the same distance with respect to the receiving electrode 32.</p><p> Each transmission electrode 31a to 31e is individually connected to the control device 24 via a single wire 38a to 38e within the frame of the data wiring 25. The receiving electrode 32 is also connected to the control device 24 via a single wire 39 within the frame of the data wiring 25. To prevent parasitic capacitance in the data wiring 25, the single wire 39 is shielded by a so-called protective shield 40 in the form of a conductor placed at ground potential M, which surrounds the single wire 39 (especially coaxially). There is. The protective shield 40 is, on the one hand, short-circuited to the ground input end of the controller 24. On the other hand, the protective shield 40 is connected to a protective electrode 41 (selectively provided) that surrounds the receiving electrode 32 in an annular shape in some cases.</p><p> As can be similarly understood from FIG. 2, Hall sensors 42 are attached to the elevating actuator 22 and the front-rear actuator 23, respectively. These Hall sensors 42 generate measurement signals in cooperation with the annular magnets (not shown) connected to the shafts of the elevating actuator 22 and the front-rear actuator 23, respectively, and based on these measurement signals, the elevating actuator 22 to State quantities such as, for example, the rotational position, the number of revolutions, and the displacement movement distance of the front and rear actuators 23 can be calculated. Correspondingly, each of the data wirings 26 and 27 has a measurement wiring 44 for feeding back the Hall signal to the control device 24 in addition to the control wiring 43 for controlling the elevating actuator 22 and the front-rear actuator 23. ..</p><p> The controller 24 of the position adjuster 20 in FIG. 2 is shown in detail in FIG. 3, which operates the frequency generator 45, the time-splitting multiplier 46, the (capacity) measurement module 47, and the respective Hall sensors 42. It has two Hall modules 48 for the purpose of and for evaluating the fed-back Hall signal, and two motor control devices 49 for operating the elevating actuator 22 and the front-rear actuator 23, respectively. Further, the control device 24 has a microcontroller 50, which is technically connected to a frequency generator 45, a time division multiplier 46, a measurement module 47, a hall module 48, and a motor control device 49.</p><p> A control program (detailed below) is given to the microcontroller 50 by software technology, and this control program detects the relative position of the head 4 with respect to the actual position of the headrest by the action of the proximity sensor 21 (in short). , The headrest 3 is moved to the target position (vertical direction and horizontal direction) by operating the elevating actuator 22 and the front-rear actuator 23 according to the detected head position.</p><p> The control operation assigned to the microprocessor 50 is started, for example, by starting an automobile engine. Alternatively, the control operation may be initiated at regular time intervals and / or at the request of the vehicle user (eg, by pressing a corresponding operating button) while driving the vehicle.</p><p> In the first stage of this control operation, the headrest 3 is first displaced and adjusted to the vertical target position. For this purpose, the control device 24 first starts the search. At the beginning of the search, the headrest 3 is placed at its minimum vertical displacement distance V and minimum horizontal displacement distance H. Otherwise, the headrest 3 is moved to that position by the controller 24.</p><p> Starting from there, the microcontroller 50 operates the elevating actuator 22 via the motor controller 49 to move the headrest 3 upward. In that case, the microcontroller 50 generates an AC voltage with a frequency generator 45, especially at a frequency of about 10 Mhz. The AC voltage is sequentially applied to the transmission electrodes 31a to 31e of the proximity sensor 21 via the time division multiplier 46.</p><p> Under the influence of the voltage, the transmitting electrodes 31a to 31e alternately generate alternating electric fields F in the spatial range in front of the headrest 3. In this alternating electric field F, the transmitting electrodes 31a to 31e cooperate with the receiving electrodes 32 to electrically act as a capacitor, and the capacitance is detected by the measuring module 47.</p><p> Due to the sequential control of the transmitting electrodes 31a to 31e, the electrical signals generated at the receiving electrode 32 by the alternating electric field F are well separated in time and the received signals S associated with each transmitting electrode 31a to 31e._iIt is decomposed into (i = 1, 2, ..., 5). In the following, the received signal S₁Is on the transmitting electrode 31a, the received signal S₂Is on the transmitting electrode 31b, the received signal S₃Is on the transmitting electrode 31c, the received signal S₄Is on the transmitting electrode 31d, the received signal S₅Is defined as being associated with each of the transmitting electrodes 31e.</p><p> Each received signal S_iMeasurement module 47 is associated with capacitance measurement C_iCalculate (i = 1, 2, ..., 5) and measure these capacitances C_iIs continuously transmitted to the microprocessor 50. Its capacitance measurement C_iIs generally an arbitrary metric from which the capacitance formed between the associated transmit electrodes 31a-31e and the receiver electrode 32 can be calculated. In the variation of the control method described below, the capacitance measurement amount C_iIs an amount that is inversely proportional to the capacitance each time.</p><p> When the head 4 of the occupant 5 is inside the detection effective range 51 (shown by the broken line in FIG. 1) of the proximity sensor 21 during the search, the head 4 is between the transmitting electrodes 31a to 31e and the receiving electrode 32. Affects the capacitance formed in. This is due, on the one hand, that the head 4 acts as a dielectric in the alternating electric field F, which increases the capacitance considered for each. On the other hand, the effect of the head 4 is that the head 4 acts as a counter electrode based on the ion mobility in the human body and the grounding that is always present in a certain range of the human body, thereby the transmitting electrodes 31a-31e and the receiving electrode. Due to the reduced measurable capacitance between 32. In general, the latter effect is superior. Correspondingly, the closer the head is to the associated transmit electrodes 31a-31e, the more the capacitance measurement C._iIncreases in size.</p><p> This effect is mainly used to check whether the head position is detected during the search. Therefore, each capacitance measurement amount C_iThreshold C where_{o o}Compared to (see Figure 4). Total Capacitance Measurement C_iIs the threshold C over the entire vertical displacement distance V_{o o}If it is below, this indicates that the head 4 is not present inside the detection effective range 51. In this case, the headrest 3 is moved forward in the horizontal direction 7 and the search is repeated. As long as the head position cannot be detected over the entire horizontal displacement distance H and vertical displacement distance V, the controller 24 will place the headrest 3 and the headrest 3 in the vertical direction 6 approximately two-thirds of the maximum vertical displacement distance V. It moves to the so-called 2/3 position, which is extended upward only. The value h of the headrest vertical position h_2/3Is outlined in Figure 4. At the 2/3 position, the headrest 3 is pulled into the minimum horizontal displacement distance H.</p><p> Otherwise, if the head 4 of the occupant 5 is inside the detection range 51, then each capacitance measurement C during vertical movement of the headrest 3_i~ C₅Pass through the maximum characteristic values (see Fig. 4). In this case, the capacitance measurement amount C₃The maximum value of is the vertical target position h to be reached_sThat is, the center 34 of the headrest 3 in the vertical direction 6 is at the minimum distance from the head 4 and is almost at the same height as the eye-ear-virtual connection line of the head 4 (see FIG. 1). Headrest coincides with the vertical position h.</p><p> Capacitance measurement C due to measurement noise₃Since the detection of the maximum value of is cognitively accompanied by a relatively large measurement error, the target position h_sReach the capacitance measurement C₃Capacitance measurement C related to transmit electrode 31b and transmit electrode 31c₂, C₄Is required based on. In other words, as you can see from Fig. 4, the target position h_sIs the capacitance measurement C₂, C₄It almost coincides with the intersection 52 of.</p><p> However, the capacitance measurement C₂, C₄The intersection of is cognitively the target position h_sIs not always a sufficient standard for the arrival of. Rather (as shown in contrast to FIGS. 5 and 6), even when the center 34 of the headrest 3 in vertical 6 is mistakenly placed on the neck of the occupant 5 (see Figure 6), capacitance measurements Quantity C₂, C₄Crossing occurs. Target position h_sCapacitance measurement C associated with the central transmit electrode 31c, as an auxiliary within the framework of the control operation assigned to the microcontroller 50, to distinguish between and the mispositioning of the headrest 3 to the neck of the occupant 5.₃Is evaluated. As shown in the comparison between Fig. 5 and Fig. 6, the target position h_sCapacitance measurement in C₃The value of is the capacitance measurement C₂, C₄On the other hand, this is exactly the opposite in the case of mispositioning of the headrest 3 to the neck of occupant 5.</p><p> In a form suitable for the purpose of the control operation, the control device 24 is moving upward in the headrest 3 in the sense described above, under the condition C.₄&lt;C₂And C₃&gt; C₄Is satisfied at the same time, so that the target position h_sRecognize the arrival of. As soon as these conditions are satisfied, the control device 24 stops the elevating actuator 22.</p><p> Headrest 3 is the vertical target position h_sThis position h while moving towards_sThe microcontroller 50 takes into account the rotational values introduced into its Hall module 48 by the corresponding control of the motor controller 49 attached to the elevating actuator 22 to prevent it from "passing". h_sDisplacement movement speed d of the elevating actuator 22 already before reaching_vGradually decrease in several steps. As can be seen from Fig. 4, its displacement movement speed d_vThe first drop in is the capacitance measurement C associated with the top transmit electrode 31e.₅Is the capacitance measurement associated with the transmit electrode 31d just below it.₄It is done when crossing with. Capacitance measurement C₄Is the capacitance measurement C₃When crossing with, displacement movement speed d_vIs lowered again. In order to realize the displacement movement of the headrest 3 as "smooth" as possible, that is, without impact, the displacement movement speed d during that time._vSelectively, the capacitance measurement C₄When exceeds the maximum value (see the dashed line in the lower diagram in Figure 4), it is reduced again.</p><p> Vertical target position h_sAfter reaching, the microcontroller 50 moves to the horizontal target position L in the second process of control operation._sAdjust to aim for. Its target position L_sThe microcontroller 50 starts a horizontal search under the operation of the front-rear actuator 23, and the front component 9 of the headrest 3 is extended toward the head 4 within the frame. In the meantime, the microcontroller 50 has the capacitance measurement C shown in the top diagram of FIG.₃Track the progress of.</p><p> Capacitance measurements C detected by microcontroller 50 to numerically compensate for false capacitance based on metal components in headrest 3.₃The capacitance measurement with respect to the horizontal position of the headrest C₃Standardize to the system characteristic curve K, which represents the system dependence of. This system characteristic curve K is stored in the microcontroller 50 in the form of a list of headrest locations, and the headrest locations are interpolated by the microcontroller 50. Alternatively, the system characteristic curve K can also be stored in the form of an approximate model function. Its standardized capacitance measurement C'₃= C₃The course of / K is shown in the central diagram of Figure 7.</p><p> Horizontal target position L_sTo find the standardized capacitance measurement C'₃Remembered threshold C_hCompare with this threshold C_hWhen is exceeded (see bottom diagram in FIG. 7), the front-rear actuator 23 is stopped.</p><p> Target position L during horizontal position adjustment of headrest 3_sTo prevent "passing" the microcontroller 50, the microcontroller 50 is at target position L._sDisplacement movement speed d of the front-rear actuator 23 before_HAlso gradually decrease. In this case, the standardized capacitance measurement C'₃Is the threshold C_hWhen the threshold Cp, which is lower than that of Cp, is exceeded (see Fig. 7), the displacement movement speed d_HIs reduced.</p>

<p> FIG. 8 shows a second embodiment of the position adjusting device 20. This embodiment is the same as the embodiment of the position adjusting device 20 in FIG. 2 in that it is not described differently below. Instead of the transmitting electrodes 31a to 31e in FIG. 2, in FIG. 8, five receiving electrodes 60a to 60e are provided in the electrode regions 36 and 37 on the substrate 30 in the same geometric arrangement. Instead of the receiving electrode 32 in FIG. 2, in FIG. 8, one co-transmitting electrode 61 is provided in the electrode region 35 in the same geometric arrangement. The single wire 39 shield is not needed here. Also, the protective electrode 41 shown in FIG. 2 is not required. Instead, preferably here, the single wires 38a-38e connecting the control device 24 to the receiving electrodes 60a-60e are particularly individually electrically shielded. The corresponding shield 53 is schematically shown in FIG.</p><p> The electrode function replaced with FIG. 2 is caused by the modification of the controller 24 in FIG. Here, unlike FIG. 3, the capacitance measuring module 47 is connected to the receiving electrodes 60a to 60e via a single wire 38a to 38e. This measurement module 47 is here the received signal S transmitted separately via the single wires 38a-38e.₁~ S₅Is formed to detect at the same time. In the case of the embodiments in FIGS. 8 and 9, the time division multiplier 46 is unnecessary. The frequency generator 45 is connected to the transmit electrode 61 via a single wire 39 (also different from FIG. 3).</p><p> Except for these differences, the function of the control device 24 in FIG. 9 corresponds to the above-described embodiment. In particular, the above-mentioned control operation is similarly applied to the microcontroller 50 of FIG.</p><p> Further, FIGS. 10 to 12 show an example of the proximity sensor 21 having an electrode arrangement different from that of FIG. 2, respectively. In all the examples of the proximity sensor 21 shown here, the transmitting electrodes 31a to 31e can also be used as the receiving electrodes 60a to 60e, and the joint receiving electrode 32 can also be used as the joint transmitting electrode 61.</p>

1 (for vehicles) Seat 2 seat back 3 headrest 4 head 5 Crew 6 vertical 7 horizontal 8 back parts 9 Front parts 10 Support rod (headrest stay) 11 Headrest holder 13 Support shell 14 Cushion 15 cover 16 racks 17 holder 20 Positioning device 21 Proximity sensor 22 (Vertical) Lifting actuator 23 (horizontal) front and rear actuator 24 Control unit 25 Data wiring 26 Data wiring 27 Data wiring 30 board 31a ~ 31e Transmission electrode 32 Receiving electrode 33 Vehicle sideways 34 Headrest center 35 Electrode area 36 Electrode area 37 Electrode area 38a ~ 38e single wire 39 Single wire 40 Protective shield 41 Protective electrode 42 Hall sensor 43 Control wiring 44 Measurement wiring 45 frequency generator 46 Time Division Multiplier 47 (capacitive) measurement module 48 hole module 49 Motor controller 50 microcontroller 51 Detection scope 52 intersections 53 Shield 60a ~ 60e Receiving electrode 61 Transmission electrode d_H Displacement moving speed d_v Displacement moving speed h Headrest (vertical) position h_2/3 Headrest (vertical) position value h_s Headrest (vertical) target position L headrest (horizontal) position L_s Headrest (horizontal) target position C_{o o} Threshold C_h Threshold C_i Capacitance measurement (i = 1,2, ..., 5) C_p Threshold F alternating electric field H (horizontal) displacement distance K system characteristic curve M ground potential S_i Received signal ((i = 1,2, ..., 5) V (vertical) displacement distance