JP5134890B2 - Headrest position adjustment device and headrest position adjustment method - Google Patents

Description

  The present invention relates to a headrest position adjusting device and a headrest position adjusting method for adjusting the position of a headrest provided in a seat of a vehicle such as an automobile, and more particularly to a headrest position capable of automatically adjusting the position of the headrest to an appropriate state. The present invention relates to an adjusting device and a headrest position adjusting method.

  2. Description of the Related Art Conventionally, for example, the following is known for adjusting the position of a headrest provided in a seat of a vehicle such as an automobile. That is, the headrest driving device disclosed in the following Patent Document 1 is separated from the inside of the supporting means for movably supporting the headrest, the driving means for reciprocating the headrest, and the portion supporting the head of the headrest outer cover. A plurality of sensing electrodes, a capacitance detecting means for detecting a capacitance formed by the plurality of sensing electrodes with respect to the common potential line, and a headrest moving in a direction in which the capacitance balances And a position control means for controlling the drive means.

  And this headrest drive device, the headrest is driven so that the electrostatic capacitance is balanced and the head is positioned at the center of the plurality of detection electrodes, that is, the headrest is positioned following the movement of the head, Thereby, it is set as the structure which can adjust the position of a headrest automatically to the appropriate position (center of a head) to a head.

JP-A 64-11512

  However, in the headrest driving device disclosed in Patent Document 1 described above, the headrest is moved so that the electrostatic capacities from the plurality of detection electrodes are balanced. For this reason, for example, when the occipital shape of the head is not round and relatively flat, or when the head and each detection electrode are separated (in the case of a person sitting with the head away from the headrest) There is a possibility that the range in which the capacitance of each detection electrode balances becomes wide or the balance position does not become the center position of the head, and the headrest cannot always be adjusted to an appropriate position. There is.

  The present invention has been made in view of such problems, and ensures that the headrest is properly positioned with respect to the head in a short time regardless of the distance between the head and the headrest of the human body or the shape of the head. It is an object to provide a headrest position adjusting device and a headrest position adjusting method that can be adjusted to each other.

  The headrest position adjusting device according to the present invention includes at least two headrest position detecting devices for detecting an electrostatic capacity between a human body seated on the seat and the headrest, provided at least in front of the headrest provided on the seat of the vehicle. At least one electrode and a lower detection electrode for detecting a capacitance between the human body and the headrest, and detection signals from the upper detection electrode and the lower detection electrode. And detecting the top position of the head of the human body based on the detection signal from the upper detection electrode and detecting the horizontal center position of the head based on the detection result from the detection circuit. Accordingly, the position of the headrest with respect to the seat is adjusted to an appropriate position with respect to the head based on the top position and the horizontal center position. Characterized by comprising a position adjusting means for.

  The headrest position adjusting device according to the present invention is configured as described above, so that the position of the headrest with respect to the seat is determined based on the top position and the horizontal center position of the head of the human body. The position can be adjusted automatically and reliably. For this reason, regardless of the distance between the head of the human body and the headrest, the shape of the head, and the like, the headrest can be reliably adjusted to an appropriate position with respect to the head in a short time.

  In addition, since the position of the headrest can be automatically adjusted to an appropriate position with respect to the head, it is possible to prevent accidents such as injury to the cervical spine of the occupant at the time of a collision due to unadjusted headrest position. Furthermore, since the top position of the head and the horizontal center position can be detected based on the capacitance values from the upper detection electrode and the lower detection electrode, the position of the headrest can be adjusted based on these positions. High-accuracy position adjustment can be performed without being influenced by various factors such as the position of the shoulder or neck of the human body or the height of the sitting height.

  The upper detection electrodes are provided at least in the vicinity of both ends in the horizontal direction along the front surface of the upper portion of the front side of the headrest, and the lower detection electrodes are arranged at both ends in the horizontal direction along the front surface of the lower portion of the front side of the headrest. It may be configured to be provided at least in the vicinity of the center of the space.

  The detection circuit has a capacitance value indicated by a capacitance between the head and the vicinity of the top of the head based on a detection signal from the upper detection electrode, and the top of the head based on a detection signal from the lower detection electrode. The position of the top of the head is detected by comparing with the capacitance value indicated by the capacitance between a part of the human body other than the vicinity, and the capacitance value from each of the upper detection electrodes is compared with the horizontal value. You may be set as the structure which detects a direction center position.

  When the comparison value between the capacitance value from the upper detection electrode and the capacitance value from the lower detection electrode is not included in a preset threshold range, the position adjustment unit, The headrest is moved upward or downward until the comparison value is included in the threshold value range, and the detection circuit detects the top position when the comparison value is included in the threshold value range. After the determination, the position adjustment means moves the headrest leftward or rightward until the capacitance value from each of the upper detection electrodes becomes an equivalent detection value, and the detection circuit The horizontal center position may be determined when the values are equal.

  The upper detection electrode includes first and second detection electrodes provided in the vicinity of both ends in the horizontal direction on the front side upper part of the headrest, and the lower detection electrode is in the horizontal direction on the lower side on the front side of the headrest. You may be set as the structure which consists of a 3rd sensing electrode provided in the center vicinity position between both ends.

  The position adjusting means may be configured to move the headrest to the center position of the seat at the uppermost position or the lowermost position with respect to the seat before starting the movement of the headrest to the appropriate position. .

  The detection circuit is connected to the first, second, and third detection electrodes in a one-to-one relationship, and outputs a plurality of capacitance detection circuits that output information indicating the capacitance detected by the detection electrodes; Calculation for calculating the top position and the horizontal center position using capacitance values based on the information from a plurality of capacitance detection circuits, and outputting a signal corresponding to the calculation result information to the position adjustment means And a processing circuit.

  In addition, the detection circuit is directly connected to one of the first and second detection electrodes and connected to the other via a first switch, and the detection circuit detects electrostatic charges detected by these detection electrodes. A first capacitance detection circuit for outputting information indicating capacitance; a detection electrode connected to the first capacitance detection circuit via the first switch; and a second switch connected to the first capacitance detection circuit. A second capacitance detection circuit which is connected to the three detection electrodes via a third switch and outputs information indicating the capacitance detected by these detection electrodes; and the first and second capacitance detection circuits. An arithmetic processing circuit that calculates the top position and the horizontal center position using a capacitance value based on the information from and outputs a signal corresponding to the calculation result information to the position adjusting means. Been It may be.

  The plurality of capacitance detection circuits convert a capacitance detected by the detection electrode into a voltage, and convert an analog signal from the CV conversion circuit into a digital signal. An A / D conversion circuit may be provided.

  In addition, a plurality of auxiliary electrodes provided on the inner side of the headrest on the opposite side of the front side of the upper detection electrode and the lower detection electrode, respectively, to suppress capacitance changes due to changes in the external environment of the detection electrodes. Further, the plurality of auxiliary electrodes may be configured to be supplied with the same potential as each of the detection electrodes.

  Further, the auxiliary electrode may be further provided on the seat side of the headrest at least in the vicinity of the lower detection electrode.

  The headrest position adjusting method according to the present invention includes at least two upper detection electrodes provided at a front lower portion of a headrest provided in a vehicle seat and at least one lower detection electrode provided at a lower front side of the headrest. Detecting the electrostatic capacity between the human body seated on the seat and the headrest, and detecting the electrostatic capacity based on detection signals from the upper detection electrode and the lower detection electrode And a horizontal center position of the head is detected based on a detection signal from the upper detection electrode, and the headrest is detected based on the detected top position and horizontal center position. The position with respect to the seat is adjusted to an appropriate position with respect to the head.

  The headrest position adjustment method according to the present invention is configured as described above, so that the position of the headrest relative to the seat with respect to the head is determined based on the top position of the head of the human body and the horizontal center position. It can be automatically and reliably adjusted to an appropriate position. For this reason, regardless of the distance between the head of the human body and the headrest, the shape of the head, and the like, the headrest can be reliably adjusted to an appropriate position with respect to the head in a short time.

  In addition, since the position of the headrest can be automatically adjusted to an appropriate position with respect to the head, it is possible to prevent accidents such as injury to the cervical spine of the occupant at the time of a collision due to unadjusted position of the headrest. Furthermore, since the top position of the head and the horizontal center position can be detected based on the capacitance values from the upper detection electrode and the lower detection electrode, the position of the headrest can be adjusted based on these positions. High-accuracy position adjustment can be performed without being influenced by various factors such as the position of the shoulder or neck of the human body or the height of the sitting height.

  Further, the headrest position adjusting device according to the present invention is provided at each position near both ends in the horizontal direction along the front surface of the upper portion of the front surface of the headrest provided in the seat of the vehicle, and the human body seated on the seat and the headrest Two upper detection electrodes for detecting a capacitance between the headrest and one at a position near the center between both ends in the horizontal direction along the front surface of the lower portion on the front surface side of the headrest, between the human body and the headrest According to a lower detection electrode for detecting capacitance, a detection circuit for detecting the position of the head of the human body based on detection signals from the upper detection electrode and the lower detection electrode, and a detection result from the detection circuit And a position adjusting means for adjusting the position of the headrest relative to the seat to an appropriate position relative to the head.

  According to the present invention, the position of the headrest with respect to the seat can be automatically and reliably adjusted to an appropriate position with respect to the head based on the top position and the horizontal center position of the head of the human body, Provided is a headrest position adjustment device and a headrest position adjustment method capable of adjusting the headrest to an appropriate position with respect to the head in a short time regardless of the distance between the head of the human body and the headrest or the shape of the head. can do.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a headrest position adjusting device and a headrest position adjusting method according to the invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram illustrating an example of a vehicle seat in which the headrest position adjusting device according to the first embodiment of the present invention is arranged, and FIG. 2 is an explanatory diagram illustrating an arrangement example of a part of the headrest position adjusting device in the headrest FIG. 3 is a block diagram showing an example of the overall configuration of the headrest position adjusting device.

  FIG. 4 is a block diagram showing a configuration example of a CV conversion circuit in the capacitance detection circuit in the detection circuit of the headrest position adjustment device, and FIG. 5 is an operation waveform of the detection circuit of the headrest position adjustment device. FIG. 6 and FIG. 7 are operation explanatory diagrams for explaining the operation of the headrest position adjusting device.

  As shown in FIG. 1 and FIG. 2, the headrest position adjusting device 100 according to the first embodiment is provided in a seat 40 such as a vehicle, for example, a capacitance sensor unit 10 disposed in a headrest 43 of the seat 40, The drive motor unit 30 is disposed on the backrest 41 of the seat 40. In the headrest position adjustment device 100 according to the first embodiment, the capacitance sensor unit 10 and the drive motor unit 30 are electrically connected by a harness 29, for example.

  The capacitance sensor unit 10 is formed on the other surface side of the substrate 19, for example, the first detection electrode 11, the second detection electrode 12, and the third detection electrode 13 formed on one surface side of the substrate 19. A predetermined portion of the human body 48 seated on the seating portion 42 of the seat 40 (for example, a portion different from the head 49 such as the neck portion 48a and the shoulder portion 48b (see FIG. 6)), A head 49 (particularly the top 49a) is detected. That is, the capacitance sensor unit 10 detects a capacitance between a predetermined portion of the human body 48 and the head 49 and the headrest 43 (specifically, the first to third detection electrodes 11 to 13).

  The board | substrate 19 is comprised by the flexible printed circuit board, the rigid board | substrate, or the rigid flexible board | substrate, for example, and the 1st-3rd detection electrodes 11-13 are a polyethylene terephthalate (PET), a polyethylene naphthalate (PEN), a polyimide (PI). It is made of a conductor such as copper, copper alloy or aluminum patterned on a substrate 19 made of an insulator such as polyamide (PA) or epoxy resin.

  The first to third detection electrodes 11 to 13 are disposed on the front side of the headrest 43, for example, and the first and second detection electrodes 11 and 12 that are upper detection electrodes are the lower detection electrodes at the upper part on the front side. The detection electrodes 13 are arranged at the lower part on the front side. Specifically, the first detection electrode 11 is located near the left end in the horizontal direction (to the left side) along the front surface of the upper portion of the front side of the headrest 43, and the second detection electrode 12 is right in the horizontal direction (to the right side). Each of the third detection electrodes 13 is disposed at a position near the center between both ends in the horizontal direction along the front surface of the lower portion of the front surface of the headrest 43.

  Each of the detection electrodes 11 to 13 is formed in a rectangular shape, detects a capacitance between a predetermined part of the human body 48 seated on the seat 40 and the head 49, and detects the top of the head 49 a of the head 49. The position (top position) and the horizontal center position of the head 49 (intermediate position from the left and right ends) can be detected.

  The headrest position adjusting device 100 detects the top position and the horizontal center position of the head 49 using the capacitance value indicated by the capacitance based on the detection signals from the detection electrodes 11 to 13. Then, the position of the headrest 43 with respect to the seat 40 is adjusted to an appropriate position with respect to the head 49 based on the top position and the horizontal center position.

  Based on the detection signals from the first to third detection electrodes 11 to 13 (that is, for example, the detection circuit 20 relatively compares the capacitance values indicated by the detection signals from the detection electrodes 11 to 13, for example). And the top position of the head 49 described above is detected. Further, the detection circuit 20 is based on the detection signals from the first and second detection electrodes 11 and 12 on the upper front side of the headrest 43 (that is, for example, the static signals indicated by the detection signals from the detection electrodes 11 and 12, respectively). By comparing the capacitance values, the horizontal center position of the head 49 described above is detected.

  The first and second detection electrodes 11 and 12 mainly detect the electrostatic capacitance in the vicinity of the top 49 a of the head 49, and the third detection electrode 13 is a part of the human body 48 other than the top 49 a of the head 49. For example, the capacitance of the neck portion 48a and the shoulder portion 48b is detected.

  Specifically, for example, the detection circuit 20 subtracts the total value of the capacitance detected by the first and second detection electrodes 11 and 12 from the capacitance value detected by the third detection electrode 13. The comparison value is used, and it is determined whether the comparison value is in a range above or below a preset threshold (that is, whether it is included above or below the threshold). The position of the top of the head is detected.

  In addition, the detection circuit 20 compares the capacitance value detected by the third detection electrode 13 with the total value of the capacitance detected by the first and second detection electrodes 11 and 12, or the third detection A value obtained by multiplying the capacitance value detected by the electrode 13 by a constant is divided by a value obtained by multiplying the total value of the capacitance detected by the first and second detection electrodes 11 and 12 by another constant. Thus, the position of the top of the head may be detected.

  Then, the detection circuit 20 detects, for example, the position of the top of the head, and then determines whether the capacitance values detected by the first and second detection electrodes 11 and 12 are equal to each other, for example. By comparing these, the horizontal center position of the head 49 is detected.

  For example, as shown in FIG. 3, the detection circuit 20 is connected to the first to third detection electrodes 11 to 13 on a one-to-one basis, and outputs information indicating the capacitance detected by the detection electrodes 11 to 13. A plurality of capacitance detection circuits 21, 22, and 23, connected to the capacitance detection circuits 21 to 23, and using capacitance values based on information output from the capacitance detection circuits 21 to 23. The head top 49 and the horizontal center position of the head 49 are calculated, and a control signal for moving or stopping the headrest 43 to an appropriate position with respect to the head 49 according to the calculation result information is sent to the drive motor unit 30. And an arithmetic processing circuit 28 for outputting to a motor drive circuit (not shown).

  Each of the plurality of capacitance detection circuits 21 to 23 converts, for example, capacitances (Capacitance) detected by the first to third detection electrodes 11 to 13 into voltages (Voltage). , 23a and A / D conversion circuits 21b, 22b, 23b for converting analog signals indicating voltages from the CV conversion circuits 21a to 23a into digital signals.

  Each capacitance detection circuit 21-23 outputs a pulse signal whose duty ratio changes according to the capacitance between each detection electrode 11-13 and the head 49, neck 48a or shoulder 48b of the human body 48. And smoothing and outputting a detection signal. The arithmetic processing circuit 28 is composed of, for example, a CPU or FPGA, and detects the position of the top of the head 49 by relatively comparing the capacitance values based on the detection signals from the capacitance detection circuits 21 to 23. At the same time, the horizontal direction center position of the head 49 is detected by comparing the capacitance values based on the detection signals from the capacitance detection circuits 21 and 22, and the position of the headrest 43 is changed with respect to the drive motor unit 30. A control signal based on the calculation result is output.

  As shown in FIG. 4, the CV conversion circuits 21 a to 23 a of the capacitance detection circuits 21 to 23 change the duty ratio according to the capacitance C. For example, the CV conversion circuits 21 a to 23 a have a constant period trigger signal TG. A trigger signal generation circuit 101 that outputs a signal, a timer circuit 102 that outputs a pulse signal Po whose duty ratio changes depending on the magnitude of the capacitance C connected to the input terminal, and a low-pass filter that smoothes the pulse signal Po (LPF) 103.

  The timer circuit 102 includes, for example, two comparators 201 and 202, and an RS flip-flop circuit (hereinafter referred to as “RS-FF”) in which outputs of the two comparators 201 and 202 are input to a reset terminal R and a set terminal S, respectively. 203), a buffer 204 that outputs the output DIS of the RS-FF 203 to the LPF 103, and a transistor 205 that is turned on / off by the output DIS of the RS-FF 203.

  The comparator 202 compares the trigger signal TG as shown in FIG. 5 output from the trigger signal generation circuit 101 with a predetermined threshold value Vth2 divided by the resistors R1, R2, and R3, and generates a trigger signal TG. Output synchronized set pulse. This set pulse sets the Q output of the RS-FF 203.

  This Q output turns off the transistor 205 as a discharge signal DIS, and between each detection electrode 11-13 and the ground, between the grounding capacitance C of each detection electrode 11-13 and the input terminal and the power supply line. The battery is charged at a speed determined by a time constant by a resistor R4 connected to. As a result, the potential of the input signal Vin increases at a speed determined by the capacitance C.

  When the input signal Vin exceeds the threshold value Vth1 determined by the resistors R1, R2, and R3, the output of the comparator 201 is inverted and the output of the RS-FF 203 is inverted. As a result, the transistor 205 is turned on, and the charge accumulated in each of the detection electrodes 11 to 13 is discharged via the transistor 205.

  Therefore, as shown in FIG. 5, the timer circuit 102 has a duty ratio based on the electrostatic capacitance C between each of the detection electrodes 11 to 13 and the head 49, neck 48a, or shoulder 48b of the approaching human body 48. An oscillating pulse signal Po is output. The LPF 103 smoothes this output to output a DC detection signal Vout as shown in FIG.

  Thus, the detection signals Vout output from the CV conversion circuits 21a to 23a are converted into digital signals by the A / D conversion circuits 21b to 23b. In FIG. 5, a waveform indicated by a solid line and a waveform indicated by a dotted line indicate that the former has a smaller capacitance than the latter, and for example, the latter indicates an object approaching state.

  The drive motor unit 30 calculates the top position of the top 49a of the head 49 and the horizontal center position of the head 49 based on the detection signals Vout from the capacitance detection circuits 21 to 23, and these top positions The headrest 43 is controlled by controlling a drive motor (not shown) based on a control signal from the arithmetic processing circuit 28 that moves or stops the headrest 43 to an appropriate position with respect to the head 49 based on the horizontal center position. A motor drive circuit that changes the position of the headrest 40 to the appropriate position and a drive motor that actually moves the position of the headrest 43 by the control of the motor drive circuit. Specifically, the drive motor drives the support shaft 43a of the headrest 43 so as to be movable in the vertical direction, the horizontal direction, and the front-back direction.

  In the initial state before the movement of the headrest 43 to the appropriate position, the drive motor unit 30 moves the headrest 43, for example, to the uppermost position with respect to the seat 40 (the position of the headrest 43 is farthest from the backrest 41). Position) or the lowest position (the position of the headrest 43 is closest to the backrest 41).

  The headrest position adjusting device 100 configured as described above operates as follows, for example. Here, for example, the capacitance value C1 detected by the first detection electrode 11 from the capacitance value C3 detected by the third detection electrode 13 and the capacitance value C2 detected by the second detection electrode 12 are used. A value obtained by subtracting the sum of the values will be referred to as a comparison value CA (CA = C3− (C1 + C2)), and a preset threshold value will be described as a threshold value CB.

  First, the vertical position adjustment operation of the headrest 43 will be described. Here, the operation in the case where the headrest 43 is at the lowermost position described above will be described. As shown in FIG. 6A, when the headrest 43 is at the lowermost position, the first and second detection electrodes 11 and 12 are in positions corresponding to the vicinity of the lower back of the head 49 of the human body 48 and the horizontal direction. In other words, the third detection electrode 13 is at a position corresponding to the vicinity of the shoulder portion 48b below the neck portion 48a and in the horizontal direction.

  In this case, the distance from each of the detection electrodes 11 to 13 to each part of the human body 48 (in the vicinity of the head 49 and the shoulder 48b) is actually the first and second detection electrodes 11 and 12 at both ends of the headrest 43. Since it is located on the side, it is farther from the third detection electrode 13, but when viewed from the side, it is substantially equal as shown. Therefore, in the embodiment shown in FIG. 6A, the values of the capacitances C1 + C2 and C3 detected by the detection circuit 20 are substantially equal as shown in the figure, and the comparison value CA is smaller than the threshold value CB. State (comparison value CA <threshold value CB). That is, when the headrest 43 is below the appropriate position with respect to the head 49, the comparison value CA is smaller than the threshold value CB.

  In such a state, while the headrest 43 is raised, the values of the capacitances C1 to C3 of the detection electrodes 11 to 13 are monitored, and the comparison value CA becomes larger than the threshold value CB. At this point, the headrest 43 is stopped. That is, for example, when the headrest 43 is lifted from the lowermost position and moved to a position as shown in FIG. 6B, the first and second detection electrodes 11 and 12 are near the upper back of the head 49 of the human body 48. The third detection electrode 13 is in a position corresponding to the vicinity of the neck portion 48a and the horizontal direction.

  Also in this case, the distances from the detection electrodes 11 to 13 to the respective parts of the human body 48 (in the vicinity of the head 49 and the neck 48a) and the values of the detected capacitances C1 to C3 are the same as described above and as illustrated. The comparison value CA is smaller than the threshold value CB (comparison value CA <threshold value CB). Therefore, the headrest 43 is still below the proper position with respect to the head 49.

  When the headrest 43 is further raised and moved to a position as shown in FIG. 6C, the first and second detection electrodes 11 and 12 are horizontally aligned with the vicinity of the top 49a of the head 49 of the human body 48. The third detection electrode 13 is in a position corresponding to the horizontal position in the vicinity of the lower back of the back of the head 49.

  In this case, the portions near the head 49 from the first and second detection electrodes 11 and 12 are reduced, and the values of the capacitances C1 and C2 detected by the first and second detection electrodes 11 and 12 are reduced. However, since the value of the capacitance C3 detected by the third detection electrode 13 is substantially the same as that described above, the comparison value CA is larger than the threshold value CB (comparison value CA> threshold value CB). Become. That is, when the headrest 43 is in an appropriate position with respect to the head 49, the comparison value CA is larger than the threshold value CB.

  If it will be in such a state, the raise of the headrest 43 will be stopped and the operation | movement of the upward position adjustment of the headrest 43 will be complete | finished. The headrest position adjusting device 100 can be set in one direction (for example, for example, if the position of the headrest 43 in the vertical direction with respect to the head 49 is set in advance based on the relationship between the positions of the detection electrodes 11 to 13 and the threshold value CB. The position can be adjusted only by the operation in the upward direction.

  On the other hand, when the headrest 43 is in the uppermost position described above, the headrest 43 is in the uppermost position as shown in FIG. 6 (d), so that the first and second detection electrodes 11, 12 are in the human body 48. The third detection electrode 13 is in a position corresponding to the vicinity of the lower part of the back of the head 49 and in the horizontal direction.

  In this case, since the distance from the first and second detection electrodes 11 and 12 to the head 49 is large, the value of the capacitance C1 + C2 detected by the first and second detection electrodes 11 and 12 is very small. However, the value of the capacitance C3 detected by the third detection electrode 13 depends on the distance from the third detection electrode 13 to the human body 48, but is larger than the capacitance C1 + C2.

  Therefore, the comparison value CA is larger than the threshold value CB (comparison value CA> threshold value CB). In such a state, the static electricity of each of the detection electrodes 11 to 13 is lowered while the headrest 43 is lowered. The values of the electric capacities C1 + C2 and C3 are monitored, and the headrest 43 is stopped when the comparison value CA becomes smaller than the threshold value CB.

  That is, for example, when the headrest 43 is lowered from the uppermost position and moved to a position as shown in FIG. 6 (e), the first and second detection electrodes 11 and 12 are moved to the top 49 a of the head 49 of the human body 48. The third detection electrode 13 is in a position corresponding to the vicinity of the lower part of the back of the head 49 and the position corresponding to the horizontal direction.

  In this case, the portion close to the head 49 from the first and second detection electrodes 11 and 12 increases, and the value of the capacitance C1 + C2 detected by the first and second detection electrodes 11 and 12 increases. However, since the value of the capacitance C3 detected by the third detection electrode 13 is substantially the same as that described above, the comparison value CA is smaller than the threshold value CB (comparison value CA <threshold value CB). Become.

  If it will be in such a state, the descent | fall of the headrest 43 will be stopped and the operation | movement of the downward position adjustment of the headrest 43 will be complete | finished. Therefore, the headrest position adjusting device 100 can adjust the position not only in the upward direction described above but also in only one direction of operation in the downward direction, for example.

  Next, the operation of adjusting the position of the headrest 43 in the left-right direction after the position of the headrest 43 in the vertical direction is determined will be described. When the vertical position of the headrest 43 is determined, the capacitance values C1 and C2 from the first and second detection electrodes 11 and 12 are compared. Specifically, for example, in the case shown in FIG. 7A, it can be said that the head 49 is near the center in the left-right direction with respect to the headrest 43, so the first and second detection electrodes 11, 12 The detected capacitances C1 and C2 are substantially equal (C1≈C2), and it is determined that the head 49 is in the horizontal center position, and the headrest 43 is not moved in the left-right direction, but is in an appropriate position. End position adjustment.

  On the other hand, as shown in FIG. 7B, when the head 49 is shifted to the left with respect to the headrest 43, the value of the capacitance C1 detected by the first detection electrode 11 decreases, and the second The value of the capacitance C2 detected by the detection electrode 12 increases (C1 <C2). For this reason, the headrest 43 is moved to the left, the operation is stopped at a position where the values of the capacitances C1 and C2 are substantially equal, and the headrest 43 is stopped at the horizontal center position of the head 49. The position adjustment is finished.

  Further, as shown in FIG. 7C, when the head 49 is shifted to the right with respect to the headrest 43, the value of the capacitance C2 detected by the second detection electrode 12 decreases, and the first The value of the capacitance C1 detected by the detection electrode 11 increases (C1> C2). For this reason, the headrest 43 is moved rightward, the operation is stopped at a position where the values of the capacitances C1 and C2 are substantially equal, and the headrest 43 is stopped at the horizontal center position of the head 49. The position adjustment is finished.

  As described above, in the headrest position adjusting device 100, the headrest 43 can be adjusted to an appropriate position with respect to the head 49 by a single operation in the vertical direction and the horizontal direction. In addition, since the headrest position adjustment apparatus 100 has arrange | positioned the 1st-3rd detection electrodes 11-13 to the front side upper part and lower part of the headrest 43 as mentioned above, it performs position adjustment effectively also in the following cases. be able to.

  That is, although illustration is omitted, for example, even when the head 49 of the human body 48 is separated from the detection electrodes 11 to 13 (when the head 49 is separated from the headrest 43), the first and second detection electrodes 11 are used. , 12 are in positions corresponding to the horizontal direction above the vicinity of the top 49a, the value of the capacitance C1 + C2 is smaller than the value of the capacitance C3. At the same time, if the first and second detection electrodes 11 and 12 are in positions corresponding to the horizontal direction below the vicinity of the top 49a, the value of the capacitance C1 + C2 is substantially equal to the value of the capacitance C3 or growing.

  Further, for example, even when the occipital shape of the head 49 of the human body 48 seated on the seat 40 is substantially flat (that is, when there is little change in capacitance due to shape change such as unevenness), the first If the second detection electrodes 11 and 12 are at positions corresponding to the horizontal direction above or below the vicinity of the top 49a, the value of the capacitance C1 + C2 similarly changes with respect to the capacitance C3.

  Furthermore, if the top position is detected in this way and the vertical position of the headrest 43 is determined, the values of the capacitances C1 and C2 from the first and second detection electrodes 11 and 12 are compared. It is possible to detect the position of the headrest 43 in the left-right direction (horizontal direction) and adjust the position of the headrest 43 to an appropriate position with respect to the head 49. Accordingly, even in such a case, if the position adjustment is performed using the comparison value CA based on the capacitances C1 to C3, the threshold value CB, and the capacitances C1 and C2, the headrest 43 can be accurately performed in a short time. Can be reliably adjusted to an appropriate position with respect to the head 49.

  For example, if only the position of the top of the head 49a of the head 49 is detected, it is sufficient to provide one detection electrode on the front side upper portion of the headrest 43. However, as described above, the capacitance C1 When the distance between the seated human body 48 and the headrest 43 is changed by using the value of .about.C3 (for example, comparing the value of the capacitance C1 + C2 with the value of the capacitance C3, etc.) Also, in all cases such as when the occipital shape of the head 49 is different, the headrest 43 can be moved to appropriate positions in the vertical direction and the horizontal direction with respect to the head 49.

  FIG. 8 is a block diagram showing an example of the overall configuration of the headrest position adjusting device according to the second embodiment of the present invention. In the following description, parts that are the same as those already described are denoted by the same reference numerals, description thereof is omitted, and descriptions other than those particularly related to the invention may be omitted.

  As shown in FIG. 8, in the headrest position adjusting apparatus according to the second embodiment, the detection circuit 20A includes two capacitance detection circuits 21 and 23 and three switches SW1, SW2, and SW3. The third detection electrodes 12 and 13 are different from the detection circuit 20 of the previous example in that the third detection electrodes 12 and 13 are connected to the capacitance detection circuits 21 and 23 via these switches SW1 to SW3.

  Specifically, in the detection circuit 20A, the first detection electrode 11 is directly connected to the capacitance detection circuit 21, and the second detection electrode 12 is connected via the switch SW1. The second detection electrode 12 is connected to the capacitance detection circuit 23 via the switch SW2, and the third detection electrode 13 is connected to the capacitance detection circuit 23 via the switch SW3.

  Each of these switches SW1 to SW3 is configured by an electrical switch such as an FET (field effect transistor) or a mechanical switch such as a relay switch. The control lines (not shown) of the switches SW1 to SW3 are connected to the arithmetic processing circuit 28, respectively.

  In the detection circuit 20A, when adjusting the position of the headrest 43 in the vertical direction, first, the switches SW1 and SW3 are closed (ON), and the switch SW2 is opened (OFF). Thus, the first and second detection electrodes 11 and 12 are connected to the capacitance detection circuit 21 in an integrated state, and the third detection electrode 13 is connected to the capacitance detection circuit 23.

  A value obtained by subtracting the capacitance value CN detected by the capacitance detection circuit 21 from the capacitance value CM detected by the capacitance detection circuit 23 is set as a comparison value CA (CA = CM−CN). With the threshold value set in advance as the threshold value CB, the position adjustment operation is performed by performing the same process as the process described in the first embodiment.

  That is, when adjusting the position by raising the headrest 43 from the lowermost position, when the comparison value CA becomes equal to or greater than the threshold value CB, the elevation of the headrest 43 is stopped and the headrest 43 is lowered from the uppermost position. When the position adjustment is performed, when the comparison value CA becomes equal to or less than the threshold value CB, the descent of the headrest 43 is stopped to determine the vertical position.

  When the vertical position of the headrest 43 is determined in this way, the switches SW1 and SW3 are then opened (OFF) and the switch SW2 is closed (ON). Thus, the first detection electrode 11 is connected to the capacitance detection circuit 21, the second detection electrode 12 is connected to the capacitance detection circuit 23, and the third detection electrode 13 is in an open (OFF) state. .

  In this state, for example, when the comparison value CA is a positive value, it is in the direction of the second detection electrode 12 (that is, the left direction). If the headrest 43 is moved in the right direction and the headrest 43 is stopped when the absolute value of the comparison value CA becomes equal to or less than the threshold value CB, position adjustment to an appropriate position can be performed.

  FIG. 9 is a block diagram illustrating an example of the overall configuration of a headrest position adjusting device according to a third embodiment of the present invention. As shown in FIG. 9, in the headrest position adjustment device according to the third embodiment, the detection circuit 20B performs a differential operation, and includes one capacitance detection circuit 29 and three switches SW1 to SW3. This is different from the detection circuit 20A of the previous example.

  Specifically, in the detection circuit 20B, the first detection electrode 11 is connected to the negative input end of the CV conversion circuit 29a of the capacitance detection circuit 29, and the second detection electrode 12 is connected via the switch SW1. Similarly, it is connected to the negative input end. The second detection electrode 12 is connected to the positive input end of the CV conversion circuit 29a via the switch SW2, and the third detection electrode 13 is also connected to the positive input end via the switch SW3. Yes.

  In the detection circuit 20B, when adjusting the position of the headrest 43 in the vertical direction, first, the switches SW1 and SW3 are closed (ON), the switch SW2 is opened (OFF), and the first and second detection electrodes 11 are set. , 12 are connected to the negative input end of the CV conversion circuit 29a, and the third detection electrode 13 is connected to the positive input end.

  The arithmetic processing circuit 28 monitors the output voltage V obtained by subtracting the detection value at the negative input end from the value obtained by adding the detection value at the positive input end to a predetermined center voltage. The position adjustment operation is performed by comparing the value Vth and performing the same processing as the processing described in the first and second embodiments.

  That is, when adjusting the position by raising the headrest 43 from the lowermost position, when the output voltage V becomes equal to or higher than the threshold value Vth, the elevation of the headrest 43 is stopped and the headrest 43 is lowered from the uppermost position. When the position adjustment is performed, when the output voltage V becomes equal to or less than the threshold value Vth, the descent of the headrest 43 is stopped to determine the vertical position.

  Once the vertical position is determined, the switches SW1 and SW3 are opened (OFF), the switch SW2 is closed (ON), and the first detection electrode 11 is connected to the negative input terminal of the CV conversion circuit 29a. Connect the second sensing electrode 12 to the positive input end. In this state, if the value obtained by subtracting the predetermined center voltage from the output voltage V is a positive value, it is in the direction of the second detection electrode 12, and if it is a negative value, it is in the direction of the first detection electrode 11. The headrest 43 is moved. If the headrest 43 is stopped when the absolute value of the output voltage V becomes equal to or lower than the threshold value Vth, position adjustment to an appropriate position can be performed.

  As described above, the headrest position adjusting device according to the first to third embodiments described above moves the headrest 43 in one direction from the above-described initial state (the state in which the headrest 43 is at the lowermost position or the uppermost position) in the vertical direction. The position of the top 49a of the head 49 is detected simply by moving the head 49, and the center position in the horizontal direction of the head 49 is detected only by moving in one of the left and right directions. The headrest 43 can be reliably arranged at an appropriate position.

  For this reason, regardless of the distance between the head 49 of the human body 48 and the headrest 43 and the shape of the headrest 49, the headrest 43 can be moved to an appropriate position with high accuracy in a short time. Thereby, it is possible to prevent accidents such as cervical spine damage of the human body 48 at the time of a collision due to the position adjustment of the headrest 43 being unadjusted.

  In addition, although the electrostatic capacitance sensor unit 10 and the drive motor unit 30 of the headrest position adjusting device are connected by the harness 29, they may be configured to be controllable by radio or the like, for example. Further, the drive motor unit 30 may be configured integrally with the capacitance sensor unit 10 and disposed on the headrest 43 side.

  Further, in the headrest position adjusting device according to the first to third embodiments, as a configuration of the detection circuit 20 that detects the position of the top of the head 49 based on the detected capacitance, C− of the capacitance detection circuit. Although the V conversion circuit using the known timer IC in which the duty ratio of the output pulse is changed by the resistor and the capacitor has been described, the present invention is not limited to this.

  That is, for example, a method of directly measuring impedance, a method of measuring an oscillation frequency by configuring an oscillation circuit, a method of measuring a charge / discharge time by configuring an RC charge / discharge circuit, and a charge charged at a known voltage with a known capacity To measure the voltage, or to measure the number of times until the specified voltage is charged to the known capacity by moving the charge multiple times. Alternatively, processing such as providing a trigger when the waveform of the capacitance is analyzed and a corresponding capacitance waveform is obtained may be performed.

  In addition, the CV conversion circuit of the capacitance detection circuit is assumed to convert capacitance to voltage. However, it may be converted into data that can be easily handled electrically or as software. Alternatively, it may be converted directly into a digital value. Furthermore, although the said 1st-3rd embodiment demonstrated the example using three detection electrodes (1st-3rd detection electrodes 11-13), the headrest position adjustment apparatus is comprised as follows, for example. It may be.

  FIG. 10 is an explanatory diagram for explaining an example of a headrest position adjusting device having another configuration. The headrest position adjusting apparatus of this example has a configuration in which the fourth and fifth detection electrodes 14 and 15 are further arranged below the first and second detection electrodes 11 and 12 in the headrest 43, and the detection circuit 20. For example, the fourth detection electrode 14 is connected to the negative input end and the fifth detection electrode 15 is connected to the positive input end so that the electrostatic capacitance C5 can be used. The value of the capacitance C4 is subtracted, and the output value is compared with a threshold value by a comparator or the like to detect the horizontal center position of the head 49.

  As such an operation of the detection circuit 20, for example, when the switch S1 is open (OFF), the switch S2 is grounded (GND), and the switch S3 is closed (ON), the switch S3 is opened (OFF). When the switch S2 is switched to Vr and the switch S1 is connected to the inverting input of the operational amplifier, the capacitances C5 and Cf are charged with C5Vr, and the capacitances C4 and Cf are charged with C4Vr.

  Next, after the switch S1 is opened (OFF) and the switch S2 is grounded (GND), the voltage V when the switch S1 is grounded (GND) is measured. The voltage at this time is V / Vr = {(Cf + C5) / Cf} − {(Cf + C4) / Cf}, and a voltage corresponding to the ratio between the capacitance C5 and the capacitance C4 is output. The horizontal center position can be detected.

  Note that a metal member may be used inside the headrest 43 and the backrest portion 41, and when the headrest 43 moves, the metal member and the first to third detection electrodes 11 to 13 (fourth). In addition, since the positional relationship with the fifth detection electrodes 14 and 15 (including these when the fifth detection electrodes 14 and 15 are present) changes, a change in capacitance due to a change in the external environment may be detected, leading to a malfunction.

  In order not to be affected by such influence, illustration is omitted, but the inner side of the headrest 43 opposite to the front side of the headrest 43 of each of the detection electrodes 11 to 13 (that is, the back side), or At the same time, an auxiliary electrode (shield electrode) for suppressing the capacitance change may be provided on the backrest 41 side in the vicinity of each of the detection electrodes 11 to 13 (particularly the third detection electrode 13).

  In this case, each shield electrode only needs to have a potential equal to that of each of the detection electrodes 11 to 13. The equivalent potential may be generated through a single amplifier (buffer) with a high input impedance from the potential applied to each of the detection electrodes 11 to 13, for example. In the case of the operational amplifier shown in FIG. If the inverting input portion is connected to the shield electrode, the same potential can be applied.

  In the first to third embodiments described above, the case where the headrest position adjusting device is applied to the headrest 43 of the seat 40 of the vehicle has been described as an example. However, the headrest position adjusting device according to the present invention is other In addition, the present invention can be applied to various seats that can adjust the position of the headrest (for example, an attraction seat, a theater seat, a massage chair, etc.).

  According to the present invention, an apparatus for adjusting the position of a headrest of a seat provided in a vehicle such as an automobile is particularly useful for highly accurate position adjustment in a short time.

It is the schematic which shows the example of the seat of the vehicle which has arrange | positioned the headrest position adjustment apparatus which concerns on 1st Embodiment of this invention. It is explanatory drawing which shows the example of arrangement | positioning in the one part headrest of the headrest position adjustment apparatus. It is a block diagram which shows the example of the whole structure of the headrest position adjustment apparatus. It is a block diagram which shows the structural example of the CV conversion circuit in the electrostatic capacitance detection circuit in the detection circuit of the headrest position adjustment apparatus. It is an operation | movement waveform diagram which shows the example of the operation | movement waveform of the detection circuit of the headrest position adjustment apparatus. It is operation | movement explanatory drawing for demonstrating operation | movement of the headrest position adjustment apparatus. It is operation | movement explanatory drawing for demonstrating operation | movement of the headrest position adjustment apparatus. It is a block diagram which shows the example of the whole structure of the headrest position adjustment apparatus which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the example of the whole structure of the headrest position adjustment apparatus which concerns on 3rd Embodiment of this invention. It is explanatory drawing for demonstrating the example of the headrest position adjustment apparatus of another structure.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Capacitance sensor part, 11 ... 1st detection electrode, 12 ... 2nd detection electrode, 13 ... 3rd detection electrode, 19 ... Board | substrate, 20 ... Detection circuit, 21-23, 29 ... Capacitance detection circuit, 21a-23a, 29a ... CV conversion circuit, 21b-23b, 29b ... A / D conversion circuit, 28 ... arithmetic processing circuit, 29 ... harness, 30 ... drive motor part, 40 ... seat, 41 ... backrest part, 42 ... Seating part, 43 ... Headrest, 43a ... Support shaft, 48 ... Human body, 49 ... Head, 49a ... Top of head.

Claims (12)

An upper detection electrode provided on at least two front upper portions of a headrest provided in a vehicle seat, and detecting an electrostatic capacity between a human body seated on the seat and the headrest;
A lower detection electrode that is provided at least on the lower front side of the headrest and detects a capacitance between the human body and the headrest;
Based on the detection signals from the upper detection electrode and the lower detection electrode, the top position of the head of the human body is detected, and the horizontal center position of the head is determined based on the detection signal from the upper detection electrode. A detection circuit to detect;
Position adjusting means for adjusting the position of the headrest relative to the seat to an appropriate position with respect to the head based on the position of the top of the head and the center position in the horizontal direction according to the detection result from the detection circuit. ,
The upper detection electrode has first and second detection electrodes provided at positions near both ends in the horizontal direction along the front surface of the upper portion of the front surface of the headrest, and the lower detection electrode is on the front surface side of the headrest. A headrest position adjustment device comprising a third detection electrode provided at a position near the center between both ends in the horizontal direction along the front surface in the lower part . The detection circuit has a capacitance value indicated by a capacitance between the head and the vicinity of the top of the head based on a detection signal from the upper detection electrode, and the top of the head based on a detection signal from the lower detection electrode. The position of the top of the head is detected by comparing with the capacitance value indicated by the capacitance between a part of the human body other than the vicinity, and the capacitance value from each of the upper detection electrodes is compared with the horizontal value. head restraint position adjusting device according to claim 1, wherein the detecting the direction center position. The detection circuit integrates a value obtained by integrating the capacitance values indicated by the capacitance between the head and the vicinity of the top of the head based on the detection signals from the first and second detection electrodes. The position of the top of the head is detected in comparison with a capacitance value indicated by a capacitance between a part of the human body other than the vicinity of the top of the head based on a detection signal from the detection electrode, and the first and second detections The headrest position adjusting device according to claim 2, wherein the horizontal center position is detected by comparing the capacitance values from the respective electrodes.   When the comparison value between the capacitance value from the upper detection electrode and the capacitance value from the lower detection electrode is not included in a preset threshold range, the position adjustment unit, The headrest is moved upward or downward until the comparison value is included in the threshold value range, and the detection circuit detects the top position when the comparison value is included in the threshold value range. After the determination, the position adjustment means moves the headrest leftward or rightward until the capacitance value from each of the upper detection electrodes becomes an equivalent detection value, and the detection circuit The headrest position adjusting device according to any one of claims 1 to 3, wherein the horizontal center position is determined when the values become equal. The position adjusting means moves the headrest to a center position of the seat at an uppermost position or a lowermost position with respect to the seat before starting the movement of the headrest to the appropriate position. The headrest position adjustment apparatus of any one of 1-4 . The detection circuit is directly connected to one of the first and second detection electrodes and is connected to the other via a first switch, and the capacitance detected by these detection electrodes is detected. A first capacitance detection circuit that outputs information to be indicated; a detection electrode connected to the first capacitance detection circuit via the first switch; and a third switch connected to the third detection circuit. A second capacitance detection circuit that is connected to the electrodes via a third switch and outputs information indicating the capacitance detected by these detection electrodes; and from these first and second capacitance detection circuits An arithmetic processing circuit that calculates the top position and the horizontal center position using a capacitance value based on the information, and outputs a signal corresponding to the calculation result information to the position adjusting means. Iko Head restraint position adjusting device according to any one of claims 1 to 5, wherein the. A plurality of auxiliary electrodes provided on the inner side of the headrest opposite to the front side of the upper detection electrode and the lower detection electrode, respectively, for suppressing a change in capacitance due to a change in the external environment of each detection electrode; ,
Wherein the plurality of auxiliary electrodes, head restraint position adjusting device of any one of claims 1-6, characterized in that the potential equivalent to the sensing electrodes is given. 8. The headrest position adjusting apparatus according to claim 7, wherein the auxiliary electrode is further provided on the seat side of the headrest at least in the vicinity of the lower detection electrode. At least is two provided on the front side upper portion of the headrest provided on a seat of a vehicle, the upper portion detection electrode you detect the capacitance between the human body and the head rest seated in the seat,
A lower detection electrode that is provided at least on the lower front side of the headrest and detects a capacitance between the human body and the headrest;
A detection circuit for detecting a position of the head of the human body based on detection signals from the upper detection electrode and the lower detection electrode;
Position adjusting means for adjusting the position of the headrest relative to the seat to an appropriate position relative to the head according to the detection result from the detection circuit ;
The upper detection electrode has first and second detection electrodes provided at positions near both ends in the horizontal direction along the front surface of the upper portion of the front surface of the headrest, and the lower detection electrode is on the front surface side of the headrest. A headrest position adjusting device comprising: a third detection electrode provided at a position near the center between both ends in the horizontal direction along the front surface in the lower part . The detection circuit has a capacitance value indicated by a capacitance between the head and the vicinity of the top of the head based on a detection signal from the upper detection electrode, and the top of the head based on a detection signal from the lower detection electrode. The headrest position adjusting device according to claim 9, wherein the head top position is detected by comparing with a capacitance value indicated by a capacitance between a part of the human body other than the vicinity.   The detection circuit integrates a value obtained by integrating the capacitance values indicated by the capacitance between the head and the vicinity of the top of the head based on the detection signals from the first and second detection electrodes. 11. The position of the top of the head is detected by comparing with a capacitance value indicated by a capacitance between a part of the human body other than the vicinity of the top of the head based on a detection signal from a detection electrode. Headrest position adjustment device. The detection circuit is directly connected to one of the first and second detection electrodes and is connected to the other via a first switch, and the capacitance detected by these detection electrodes is detected. A first capacitance detection circuit that outputs information to be indicated; a detection electrode connected to the first capacitance detection circuit via the first switch; and a third switch connected to the third detection circuit. A second capacitance detection circuit that is connected to the electrodes via a third switch and outputs information indicating the capacitance detected by these detection electrodes; and from these first and second capacitance detection circuits And an arithmetic processing circuit that calculates the position of the top of the head using a capacitance value based on the information and outputs a signal corresponding to the calculation result information to the position adjusting means. Claim 10 11 head restraint position adjusting device according.

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