JP4517883B2 - Vehicle seat - Google Patents

Description

  The present invention relates to a vehicle seat, and more particularly to control at the time of a rear collision in a vehicle seat in which a headrest is divided into upper and lower parts and individually adjustable.

  Conventionally, in a vehicle seat, it is necessary to adjust the height and angle of the headrest in order to properly support the head of the occupant.

  For this reason, there exists what comprised some headrests so that adjustment was possible independently (patent document 1). The configuration described in Patent Document 1 has a U-shape at the lower part of the headrest when viewed from the front, and a lower rotating part that rotates about an axis extending in the side part direction of the seat. By rotating so that both ends of the part are located in front, the lateral shaking of the head is suppressed.

On the other hand, there is also known one in which an attachable pillow is installed at the lower front portion of the headrest to support the occupant's neck (Patent Document 2). In the configuration described in Patent Document 2, a pillow separate from the seat is installed later.
Japanese Patent Laid-Open No. 9-075167 Registered Utility Model No. 3091897

  In the conventional vehicle seat as described above, the function at the time of rear collision, that is, rear collision from the rear side of the vehicle will be examined. The configuration described in Patent Document 1 suppresses the lateral shaking of the head at both ends by rotating the U-shaped part. It does not support or hold.

  On the other hand, in the configuration described in Patent Document 2, it is possible to attach a pillow so as to support the occupant's neck and the back of the head, but depending on the position of the pillow, the pillow is applied to the occupant's neck during a rear-end collision. It will not be possible to reduce the load. That is, it does not control the positional relationship between the headrest and the pillow at the time of a rear collision.

  During a rear-end collision, the occupant's head is likely to be subjected to a force having a direction or magnitude different from that of the upper body, which increases the load on the neck.

  2. Description of the Related Art In recent years, a vehicle seat having a mechanism called an active headrest that mechanically displaces a headrest forward using a rearward displacement of an occupant's upper body that occurs at the time of a rear collision is known. Such an active headrest is based on the premise that the headrest is integrated, and if the headrest is divided into upper and lower parts and simply adopted in a configuration that can be individually adjusted, an effective effect cannot be obtained. Occurs.

  That is, in a vehicle seat having a headrest that is divided into upper and lower parts and can be individually adjusted, even if such an active headrest is adopted, the head of the occupant is appropriately adjusted depending on the positional relationship between the two parts. In some cases, the load on the neck cannot be reduced.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a vehicle having an active headrest that has a headrest that is divided into upper and lower parts and can be individually adjusted. An object of the present invention is to appropriately hold the head of the occupant during a rear collision and reduce the load on the occupant's neck.

In order to achieve the above object, a vehicle seat according to an aspect of the present invention includes a seat back and a headrest installed around an upper end portion of the seatback, and the headrest is positioned above the headrest. And an upper headrest portion supported by the seat back and a lower moving portion disposed on the lower side of the upper headrest portion so as to be able to adjust the amount of movement in the front-rear direction with respect to the upper headrest portion. In a vehicle seat, at the time of a rear impact, at least the headrest movable means for displacing the headrest forward, and the lower moving portion with respect to the upper headrest portion corresponding to the operation of the rear impact headrest movable means from the state holding the longitudinal position, at least rearward movement is a state possible for the upper headrest portion Characterized in that a settling unit.

  According to this configuration, the headrest is displaced forward at the time of a rear collision, and the rearward movement with respect to the upper headrest portion of the lower moving portion is possible. For this reason, the contact between the neck and the head and the lower moving part is eased at the time of the rear impact, and the contact between the head and the upper headrest portion that is displaced forward is promoted. Can be held in an appropriate posture.

The rear impact headrest moving means is:
A load receiving portion that is disposed in the seat back and is displaced rearwardly with the rearward displacement of the upper body of the occupant;
Forward displacement means for displacing the headrest forward in accordance with the backward displacement of the load receiving portion.

  According to this configuration, the vehicle seat having the mechanical active headrest mechanism is configured so that the rear displacement of the upper body of the occupant is increased at the time of a rear collision, and the detection of the rear displacement of the upper body is improved, In many cases, the forward movement of the headrest is promoted. Even in such a configuration, the contact between the neck portion of the occupant and the lower moving portion can be alleviated.

  The lower moving part is configured to be able to move backward by an inertial force from the occupant to the lower moving part in the event of a collision, and a curvature radius of a bottom front side surface of the lower moving part is 10 mm or more It is characterized by being.

  According to this configuration, against the rearward and obliquely upward displacement of the occupant at the time of the rear collision, while reducing the strong contact between the occupant's neck and back and the lower moving part, The lower moving part can be moved backward more efficiently by using the pressing force.

  According to the present invention, in a vehicle seat having a headrest that is divided into upper and lower parts and can be individually adjusted, the contact between the neck and the head and the lower moving part is reduced at the time of a rear collision, and the head Since the contact with the upper headrest portion that is displaced forward is promoted, the head of the occupant can be held in an appropriate posture at the time of a rear collision.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the constituent elements described in this embodiment are merely examples, and are not intended to limit the scope of the present invention only to them.

<First Embodiment>
(In-car layout)
FIG. 8 is a schematic view schematically showing a layout in a vehicle to which a vehicle seat according to the present invention is attached.

  In FIG. 8, two rows of front seats 10 and rear seats 20 are mounted in a cabin 8 partitioned by a floor panel 1, a windshield 2, a roof panel 3 and a rear partition 4.

  There are two front seats, one for the driver's seat and one for the passenger's seat. The front and rear positions are adjusted (sliding) in the horizontal direction with respect to the steering 6 attached to the engine room 5 and the steering shaft 7, and the vertical direction with respect to the floor panel 1. It is attached to the floor panel 1 so that the position can be adjusted, and includes a seat cushion 11 serving as a seating surface, a seat back 12 functioning as a backrest, and a headrest 13 installed at an upper end portion of the seat back. The two front seats 10 can independently adjust the angle of the seat back 12 with respect to the vertical direction.

  Similarly to the front seat, the rear seat 20 includes a seat cushion 21 that serves as a seating surface, a seat back 22 that functions as a backrest, and a headrest 23 that is installed at the upper end of the seat back. Has one long surface as a whole, and is mounted so that adjustment of the horizontal position and the vertical position is impossible. The rear seat 20 is divided so that the angle with respect to the vertical direction of the seat back 22 can be adjusted independently when two people are seated, and the headrest 23 also corresponds to the two divided portions. One is provided.

  It should be noted that, depending on the vehicle specifications and the like, it is a matter of course that two independent seats similar to the front seat may be used instead of a single surface having two parts that can be divided.

  In the following description, the vehicle seat attached to the passenger seat of the front seat will be described in detail as an example of the vehicle seat according to the present invention. However, the vehicle seat according to the present invention is in accordance with the desired specifications and the like. It may be attached to the rear seat. However, the vehicle seat according to the present invention is intended to hold the occupant's head in a comfortable posture when the vehicle is tilted backward (reclining), so it is preferable to attach the vehicle seat to a position other than the driver's seat.

(Recliner mechanism)
FIG. 9 is a partially enlarged view for explaining the reclining mechanism of the vehicle seat according to the present invention.

  In FIG. 9, a cushion support plate 115 fixed to the seat cushion and a rotation plate 117 connected to the lower end of the back support plate 116 fixed to the seat back are rotatably connected by a rotation shaft 170. Yes. The rotating plate 117 is formed with a gear portion 171 having a predetermined length on the outer periphery of the lower portion, an engaging portion 172 is provided at a predetermined position, and a spring for biasing the rotating plate 117 counterclockwise to the mating portion 172. One end of the spring 118 is engaged, and the other end of the spring 118 is engaged with a support bracket 181 fixed to the cushion support plate 115. The other end of the lock plate 119 having one end of the gear portion 191 that meshes with the gear portion 171 of the rotation plate 117 is pivotally supported by the cushion support plate 115 by a pin 190, and is opposite to the gear portion 191 of the lock plate 119. An engaging portion 192 is formed on the inner surface.

  The operating lever 104 is pivotally supported by the cushion support plate 115 with a pin 140 at the base, and an engaging portion 143 to which one end of a spring 120 that urges the operating lever clockwise in the figure is engaged, And an engaging portion 142 that contacts the engaging portion 192 of the lock plate 119. When the operation bay 104 is rotated in the clockwise direction in the drawing, the engagement between the engagement portion 142 of the operation lever 104 and the engagement portion 192 of the lock plate 119 is released, and the rotation plate 117 can be rotated. Become. In this state, if the seat back is applied with a weight to the rear, which is the right side in the figure, the seat back is tilted (reclined).

(Summary of adjustment)
The adjustment of the headrest corresponding to the change in the angle of the seat back in the vehicle seat of the present embodiment having the reclining mechanism as described above will be described in detail.

  FIG. 1 is a view showing a rearward tilted state (a reclining state or a laid state) in which the angle of the seat back of the vehicle seat according to the present embodiment is changed to the horizontal side, and FIG. 2 shows the seat from the state of FIG. It is a figure which shows the standing state (inverted state or the state which raised) which changed the angle | corner of the back | bag to the vertical side.

  In FIG. 1, a vehicle seat 10 includes a seat cushion 11, a seat back 12, and a headrest 13, and a three-point seat belt that regulates the amount of movement of the occupant 20 with respect to the vehicle seat 10 at the lower abdomen and the chest. 14 is provided. The seat cushion 11 is fixed to a seat slide upper portion 111, and the seat slide upper portion 111 is coupled to a seat slide lower portion 112 so as to be slidable in the front-rear direction. The seat slide lower portion 112 is formed by a seat mount front portion 113 and a seat mount rear portion 114. Connected to the floor panel. Further, the vehicle seat 10 of the present embodiment includes an encoder that outputs a signal corresponding to the rotation angle (change) of the rotation shaft (hinge) 170 of the seat back 12 in order to detect the angle of the seat back 12. A sensor 175 including this is incorporated.

  The headrest 13 is installed around the upper end of the seatback 12 and functions as an upper headrest portion supported by the seatback by a support bar. The headrest 13 is positioned below the headrest body 131 and is located below the headrest body 131. Thus, the necklace 132 is composed of two parts that function as a lower moving part that can be adjusted in the amount of movement in the front-rear direction. The necklace is located on both sides of the upper headrest in the seat width direction, and when the necklace is located on the lower side of the upper headrest, the upper part is pivotally supported on the horizontal axis along the seat width direction of the upper headrest. And two neck support portions connected to the lower portions of the respective connection portions and extending along the seat width direction. In this embodiment, as will be described later, the necklace 132 is rotatably coupled to both sides of the headrest main body 131 and the upper portion of the headrest main body, and by adjusting the angle θ with respect to the headrest main body 131, The amount of direction movement can be adjusted.

  In the rearward tilt state shown in FIG. 1, the headrest body 131 is adjusted in the distance (height) from the seat back 12 to support the back of the occupant 20, and the neckrest 132 is the headrest body to support the occupant's neck. The amount of movement in the front-rear direction is adjusted by adjusting the angle θ with respect to 131. As shown in the drawing, when the headrest body 131 is adjusted to support the occupant's back head in a normal backward tilt state, the height of the headrest body 131 is lowered, and when adjusted to support the occupant's neck, the headrest body of the necklace 132 is adjusted. The amount of forward movement with respect to 131 increases (θ increases).

  Here, when the occupant changes the angle of the seat back 12 from the rearward inclined state shown in FIG. 1 to the standing state shown in FIG. Since the angle change fulcrum of the occupant 20 is shifted, it is necessary to adjust the height of the headrest body 131 and the amount of movement of the necklace 132 in the front-rear direction. As shown in FIG. 2, in order to properly support the occupant's back of the head in the standing state, the headrest body 131 is raised (moved upward) even in consideration of an increase in the amount of depression of the seat cushion 11. In order to reduce the burden on the occupant's head and neck at the time of a rear collision, etc., or to maintain the head and neck by a necklace in a comfortable state, In order to prevent the head and neck of the occupant from being subjected to different orientations and different loads from the upper body due to steps between the headrest body 131 and both sides of the necklace 132, the necklace 132 is attached to the headrest body 131. It is preferable to move it backward (decrease θ).

  As described above, in the configuration in which the headrest 13 is composed of the two parts of the headrest body 131 and the necklace 132, the height of the headrest body 131 is adjusted in accordance with the change in the angle of the seat back 12, and the necklace 132. Two adjustments, that is, adjustment of the amount of movement in the front-rear direction are required, which is troublesome. In this embodiment, in order to reduce the troublesome adjustment, the sensor 175 detects a change in the angle of the seat back, and adjusts the height of the headrest body 131 and the amount of movement of the necklace 132 in the front-rear direction. The adjustment means which performs these two adjustments automatically is provided.

  That is, the adjusting means of the present embodiment increases the height of the headrest body 131 and moves the necklace 132 rearward in response to the angle change from the rearward tilted state of FIG. 1 to the standing state of FIG. Let Further, the height of the headrest body 131 is lowered and the necklace 132 is moved forward in response to the change in angle from the standing state of FIG. 2 to the rearward tilted state of FIG. However, when the angle is changed from the standing state (FIG. 2) to the rearward tilted state (FIG. 1), the lower side of the headrest body 131 is arranged so that the headrest body 131 and the upper end of the seat back 12 do not contact each other. The distance h between the two is controlled to be a predetermined distance or more. This is to prevent, for example, the passenger's hair or clothing from being caught between the lower portion of the headrest body 131 and the upper end portion of the seat back 12.

  Note that the height of the headrest body 131 and the amount of movement of the necklace 132 in the front-rear direction can be adjusted manually. In particular, with regard to the amount of movement of the necklace in the front-rear direction (angle θ), for example, when the seat back is at least standing, the occupant is pushing a predetermined value (for example, 30 to 100 N horizontally in the vehicle front-rear direction). A mechanism using sliding resistance (friction) between the necklace 132 and the headrest 131 so that the amount of movement of the necklace 132 in the front-rear direction can be adjusted by pressing the necklace 132 with pressure, A friction mechanism may be provided at the pivotal support portion 132.

(Adjustment means)
FIG. 3 is a partial perspective view showing a configuration example of the adjusting means of the present embodiment. The headrest 13 is located at the center and the upper side when viewed from the front, and extends downward from both sides of the headrest body 131 when viewed from the front, with the headrest body 131 supported by the seatback 12 by two support bars 1315 and 1316. Necklace 132 that is U-shaped, penetrates the headrest body 131, and is pivotally coupled to both sides of the headrest body 131 by a pivot shaft 1314 that is fixed to the headrest body 131 by a shaft support portion 1313. It is configured. In the headrest main body 131, a motor 1311 for controlling the angle of the necklace 132 with respect to the headrest main body 131, a gear 1312 that engages with the rotation shaft of the motor 1311 and is coupled to the rotation shaft 1314 are provided. The motor 1311 is driven in response to a signal from a drive box 123 provided in the seat back 12.

  On the other hand, in the seat back 12, a seat back frame 121, a load receiving plate connected to the seat back frame 121 by a rotating shaft sleeve 124, and rotated (displaced) in accordance with a pressing force (load) on the seat back of the occupant. 122, a drive box 123 for adjusting the height of the headrest 13 is provided. A support bar sleeve 125 is attached to the rotary shaft sleeve 124 to hold two support bars attached to the headrest body 131 so that the height of the support bar can be adjusted in the vertical direction. Accordingly, when the upper body of the occupant is displaced rearward at the time of a rear collision, the load receiving plate 122 is rotated rearward, and accordingly, the two support bars attached to the rotary shaft sleeve 124 and the headrest main body 131 are rotated. As a result, the headrest 13 is displaced forward. The drive box 123 includes a motor 1231 for controlling the height of the headrest, a gear 1232 that engages with the rotation shaft of the motor 1231, an arithmetic device (not shown), and the like. The load receiving plate 122 may not be coupled to the seat back frame 121, and the rotation axis may be independent from the seat back frame 121.

  The operation of the adjusting means according to this embodiment accompanying the change in the angle of the seat back will be described. When a signal from the sensor 175 that detects the angle of the seat back 12 is input to the drive box 123, an arithmetic unit (CPU) (not shown). From the signal, the presence / absence of a change in the angle of the seat back is determined. If there is an angle change, the direction and magnitude of the change angle are determined. Then, the arithmetic unit calculates the height of the headrest 13 and the amount of movement of the necklace in the front-rear direction (angle θ) according to the direction and size of the change angle, and the motor 1231 and the necklace for controlling the height of the headrest. A drive signal for the motor 1311 for controlling the forward / backward movement amount (angle θ) is output. In response to the drive signals for the two motors, the motors 1231 and 1311 are driven to adjust the height of the headrest and the amount of movement of the necklace in the front-rear direction.

  The motor 1231 that controls the height of the headrest body 131 and the motor 1311 that controls the angle of the necklace 132 are motors that can control the rotation angle in accordance with the number of pulses output from the arithmetic unit in the drive box 123. For example, a stepping motor or a servo motor is used.

(Operation at rear impact)
The vehicle seat of the present embodiment has an active headrest mechanism that displaces the headrest forward during a rear collision as described above. The necklace 132 is attached to the headrest body 131 in response to the operation during the rear collision. On the other hand, it is configured to be movable backward. The operation at the time of the rear impact will be described with reference to FIGS.

  FIG. 5 shows the operation of the active headrest mechanism when the necklace 132 is largely moved forward by the occupant's preference in a state where the angle of the seat back 12 is close to the standing state. In FIG. 5, the state before the rear impact is indicated by a broken line a, the state at the time of the rear impact is indicated by a solid line, and the state after the rear impact is indicated by a broken line b. When a rear collision occurs in the state indicated by the broken line a, a force pressed against the seat back 12 acts on the upper body of the occupant 20, and the seat back 12 tilts backward and sinks greatly and the load receiving plate 122 is displaced rearward. Along with this, the headrest 13 coupled to the rotary shaft sleeve is displaced forward and becomes a state indicated by a solid line. After the predetermined time, the seat back has a restoring force to return backward, and the state shown by a broken line b is obtained.

  Here, when the necklace 132 is largely moved forward, the necklace 132 abuts against the neck of the occupant with a strong force at the time of the rearward collision indicated by the solid line, so that the occupant's head is slightly upward. Become. When the back tilt of the seat back returns in such a state, a force acts on the head and neck in a direction different from that of the upper body, so that the occupant feels uncomfortable or uncomfortable. In a vehicle seat that employs a mechanical active headrest, there is a tendency that the seat back sinking amount is designed to be large so that the load receiving plate 122 is easily displaced at the time of a rear collision. Is likely to occur.

  In the present embodiment, in order to prevent such inconvenience, the necklace 132 can be moved backward with respect to the headrest main body 131 in accordance with the operation of the active headrest at the time of rear collision. In this embodiment, the operation of the active headrest at the time of a rear collision is detected, and the motor 1311 that controls the movement (turning) of the necklace 132 moves the necklace 132 rearward (in the direction in which the angle θ decreases). Allows movement. The operation of the active headrest may be detected by detecting the rotation of the load receiving plate 122 or by detecting the movement of the support bars 1315 and 1316 and the headrest main body 131 that rotate together with the load receiving plate 122. Furthermore, the detection method may be electrical or mechanical.

  The backward movement at this time may be moved to a predetermined position (for example, a position where the angle θ is 20 degrees or less) by giving a drive signal to the motor 1311, or a specific command or the like may be given to the motor 1311. May be allowed to move backward by the load that the necklace 132 receives from the occupant. In any case, when the state changes from the state indicated by the broken line a in FIG. 5 to the state indicated by b, the movement to the rear position where a force of a predetermined value or more is not applied to the occupant's neck may be performed.

  FIG. 6 is a diagram showing in more detail a state in which the rearward inclination of the seat back caused by the rear collision shown by the broken line b in FIG. 5 has returned. Here, the state where the necklace 132 is moved to the rear position by the adjusting means of the present embodiment is shown. In the illustrated example, the motor 1311 is driven to return the necklace 132 to the initial position in response to the detection of the operation of the active headrest at the time of rear collision.

  FIG. 7 is a diagram illustrating a relative displacement of the head of the occupant with respect to the headrest at the time of a rear collision. In the normal state, the occupant's head is in the position indicated by A. When the vehicle is tilted backward, the upper body temporarily moves down to the position indicated by B due to the sinking of the upper body into the seat back and the backward tilt of the seat back, and the resulting seat By returning back, the occupant also moves obliquely backward and upward to the position indicated by A. At this time, if the radius of curvature of the neck portion of the necklace 132 that touches the lower part of the occupant's neck or the back of the head is small (having corners or points), only a part of the occupant's neck or part from the neck to the back This is not preferable because a force acts on. Further, in a configuration in which the necklace 132 moves rearward due to a load received from the occupant, the curvature of the necklace of the occupant of the necklace 132 or the portion of the necklace 132 that comes into contact with a portion gently curved toward the rear side from the neck to the back If the radius is small, it will be difficult for the necklace to move backwards. In particular, when the head of the occupant is displaced forward at the time of a rear collision by the active headrest, the displacement increases from the occupant's neck to the back, so that the necklace is difficult to move backward.

  In this embodiment, the radius of curvature of the front side surface of the bottom surface of the necklace 132 is increased so that the necklace 132 can easily move backward due to the load received from the occupant. Specifically, the radius of curvature of the front side surface of the bottom surface of the necklace 132 is preferably 10 mm or more.

(Control flow)
The flow of processing by the adjusting means of this embodiment will be described with reference to the flowchart of FIG.

  First, as the current data, the state of the load receiving plate, the seat back angle, the headrest height, and the necklace angle based on the output of the sensor 175 are obtained (step S401). As for the data other than the state of the load receiving plate, these data are obtained when the electric circuit of the vehicle is started, and the values are stored in a memory (not shown) provided in the drive box (RAM, etc.). If configured so, the value stored in the memory may be read when this processing is activated.

  Next, it is determined by the sensor which detects the state of a load receiving plate whether the active headrest act | operated (step S402). The rear collision may be detected by an acceleration sensor provided at the rear of the vehicle body.

  If the active headrest is not in operation, it is determined whether or not the seat back angle has been changed by the occupant's operation (step S403). This is done by monitoring the signal output of the sensor 175 that detects the seat back angle.

  When a change in the angle of the seat back is detected, the arithmetic unit in the drive box 123 calculates the angle of the seat back based on the signal output of the sensor 175, and the height of the headrest corresponding to the calculated angle of the seat back and The angle of the necklace is calculated, and the respective motors are driven to adjust the height of the headrest and the angle of the necklace (step S404).

  In step S404, if the angle change of the seat back is a change in the horizontal direction, if the height of the headrest calculated by the arithmetic unit in the drive box 123 is less than a predetermined value, the calculation result is forced. Therefore, the distance between the lower portion of the headrest and the upper end of the seat back is not less than the predetermined value.

  When it is determined in step S402 that the active headrest is activated, the necklace rotation angle θ is set so that the necklace position is at a rear position where the rotation angle θ from the initial position is a predetermined angle (20 degrees) or less. A drive signal for the motor 1311 is output to be controlled (step S405).

  Here, the operation of the active headrest and the rearward movement of the necklace may be performed substantially simultaneously, or there may be a time lag, that is, a delay time or a time lag between the two.

  Further, as described above, in the configuration in which the value obtained when the electric circuit of the vehicle is activated is stored in a memory (not shown) provided in the drive box, the value is adjusted after step S404 or S405. The value is preferably updated as current data.

  As described above, according to the present embodiment, the headrest is displaced forward at the time of a rear collision, and the lower moving portion is moved backward to a predetermined position with respect to the upper headrest portion. For this reason, the contact between the neck and the head and the lower moving part is eased at the time of the rear impact, and the contact between the head and the upper headrest portion that is displaced forward is promoted. Can be held in an appropriate posture.

(Modification)
In the embodiment described above, the configuration in which the height of the headrest body 131 and the amount of movement of the necklace 132 in the front-rear direction (rotation angle θ from the initial position) are both electrically controlled by a motor has been described as an example. The longitudinal movement amount (rotation angle θ) of the necklace 132 may be a mechanical configuration that is manually adjusted by the occupant.

  For example, it is good also as a structure which can adjust the angle with respect to the headrest main body 131 of the necklace 132 in several steps using a ratchet mechanism etc. In this case, it is preferable that the ratchet mechanism is released when the necklace 132 is rotated to the maximum movable position and can be returned to the initial position.

  In such a mechanical configuration, the ratchet mechanism may be released in step S405 in accordance with the operation of the active headrest in the control flow of FIG. In this case, it is preferable that the necklace 132 is returned with a slight load when the ratchet mechanism is released so that the necklace automatically returns to the initial position side by the load received from the rear head of the occupant at the time of the rear impact.

  If it does in this way, the effect similar to said embodiment will be acquired, simplifying a structure.

<Other embodiments>
In addition, this invention is not limited to embodiment, It includes the various other embodiment which can be considered by those skilled in the art.

  In the above embodiment, the headrest is composed of the center portion and the upper headrest body and the U-shaped necklace. However, the structure and shape of the headrest are not limited thereto, and the shape and structure of the headrest body and / or necklace. Can be various. For example, the necklace (lower moving portion) may be movable or rotated in the front-rear direction relative to the headrest body (upper headrest portion).

  Moreover, in the said embodiment, although the structure provided with the drive box which has a calculating device inside a seat back was demonstrated exemplarily, if a calculating device and a drive box are provided in a suitable position according to a structure and specification of a vehicle. The position where these are provided is not limited to the above example.

  Furthermore, the configuration for displacing the headrest forward at the time of a rear collision is not limited to the mechanical active headrest described above, and various types can be used.

It is a figure which shows the back leaning state which changed the angle of the seat back of the vehicle seat of embodiment of this invention to the horizontal side. It is a figure which shows the standing state which changed the angle of the seat back of the vehicle seat of embodiment of this invention to the vertical side. It is a fragmentary perspective view which shows the structural example of the adjustment means of embodiment. It is a flowchart of the adjustment process by the adjustment means of embodiment. It is a figure explaining a seat and a crew member's movement at the time of rear-end collision. It is a figure which shows the state shown by b of FIG. 5 in detail. It is a figure which shows the relative displacement of the passenger | crew's head with respect to a headrest at the time of a rear collision. It is the schematic which shows typically the layout in the vehicle in which the vehicle seat which concerns on this invention is attached. It is the elements on larger scale explaining the reclining mechanism of the vehicle seat which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle seat 11 Seat cushion 12 Seat back 13 Headrest 20 Crew 104 Operation lever 131 Headrest body 132 Necklace 170 Rotating shaft 175 Sensor

Claims (5)

A seat back, and a headrest installed around the upper end of the seat back,
The headrest is positioned above the headrest so that the amount of movement in the front-rear direction relative to the upper headrest portion can be adjusted between the upper headrest portion supported by the seat back and the lower side of the upper headrest portion. In the vehicle seat composed of the lower moving part disposed,
A rear impact headrest movable means for displacing at least the headrest forward at the time of a rear impact ;
Corresponding to the operation of the rear impact headrest moving means, the lower moving portion is set in a state in which it can move at least backward relative to the upper headrest portion from a state in which the lower moving portion is held in the front-rear direction position with respect to the upper headrest portion Adjusting means;
Vehicle seat, characterized in that it comprises a. Comprising a sensor for detecting the operation of the rear impact headrest moving means;
When the sensor detects the operation of the rear-end headrest moving means, the adjusting means moves the lower moving portion from the state of holding the position in the front-rear direction with respect to the upper headrest portion to the upper headrest portion. The vehicle seat according to claim 1, wherein the vehicle seat is in a state capable of at least backward movement. It has an acceleration sensor that detects rear collision,
The adjusting means detects the rear collision by the acceleration sensor, and when the rear collision headrest moving means is in operation, the adjusting means maintains the position of the lower moving portion in the front-rear direction with respect to the upper headrest portion. The vehicle seat according to claim 1, wherein the vehicle seat is in a state capable of at least moving backward with respect to the portion. The rear impact headrest moving means is:
A load receiving portion that is disposed in the seat back and is displaced rearwardly with the rearward displacement of the upper body of the occupant;
The vehicle seat according to claim 1, further comprising a front displacement unit that forwardly displaces the headrest in accordance with a rearward displacement of the load receiving portion.   The lower moving part is configured to be able to move backward by an inertial force from the occupant to the lower moving part in the event of a collision, and a curvature radius of a bottom front side surface of the lower moving part is 10 mm or more The vehicle seat according to claim 1, wherein:

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