CN118107454A - Chair seat - Google Patents

Abstract

A seat (1) is provided with: a main pad (15) for receiving the load of a seated person; a sub-pad (16) fitted in a recess (17) formed in a surface of the main pad (15) opposite to the surface receiving the load; a piezoelectric sensor (21) that is disposed on the surface of the sub-pad (16) that receives the load, and that senses and detects a ballistocardiogram of the seated person; and an sandwiching member (23) that is raised from the piezoelectric sensor by a predetermined height, and is interposed between the piezoelectric sensor (21) and a bottom surface (17A) of the recess (17) that faces the piezoelectric sensor (21), and is configured so as to be capable of pressing a part of the piezoelectric sensor (21).

Description

Chair seat

Technical Field

The present disclosure relates to a seat provided to a moving body.

Background

Patent document 1 describes a seat cushion for a vehicle seat in which a piezoelectric thin film sensor is disposed in a recess of a base cushion material, and a cover cushion material is disposed in the recess so as to cover the piezoelectric thin film sensor.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication 2016-146953

Disclosure of Invention

Problems to be solved by the invention

The seat cushion described in patent document 1 has a problem that the strain amount of the piezoelectric thin film sensor is reduced.

The present disclosure has been made in view of the above-described problems, and an object thereof is to provide a seat in which the strain amount of a piezoelectric sensor can be increased.

Means for solving the problems

In order to solve the above-described problems, a seat according to one embodiment of the present disclosure includes: a main pad for receiving a load of a seated person; a sub-pad fitted in a recess formed in a surface of the main pad opposite to a surface receiving the load; a piezoelectric sensor disposed on a surface of the sub-pad that receives the load, and configured to sense and detect a ballistocardiogram of the seated person; and an sandwiching member that is raised from the piezoelectric sensor by a predetermined height, and is interposed between the piezoelectric sensor and a bottom surface of the recess facing the piezoelectric sensor, and is configured to be capable of pressing a part of the piezoelectric sensor.

Effects of the invention

According to one aspect of the present disclosure, the strain amount of the piezoelectric sensor can be increased.

Drawings

Fig. 1 is a perspective view showing an example of the appearance of a seat.

Fig. 2 is a view showing an example of a seating surface of the seat.

Fig. 3 is a view showing an example of a cross-sectional view in the direction III-III in fig. 2.

Fig. 4 is a perspective view showing an example of the sandwiching member.

Fig. 5 is an enlarged view of the V portion in fig. 3, and shows an example of a deformation state of the piezoelectric sensor before and after seating of the seated person.

Fig. 6 is a diagram showing an example of a signal waveform of a heart attack of a seated person detected by a piezoelectric sensor of a seat under a static condition in a state where an sandwiching member is present and a state where the sandwiching member is not present, respectively.

Fig. 7 is a diagram showing an example of the ratio of RRI estimation accuracy obtained from the sensing detection results obtained in the state where the sandwiching member is not present and the state where the sandwiching member is present, respectively, under the static condition.

Fig. 8 is a diagram showing an example of the ratio of RRI estimation accuracy obtained from the sensing detection results obtained in the state where the sandwiching member is not present and the state where the sandwiching member is present under the dynamic condition.

Fig. 9 is a diagram illustrating an example of a distribution chart of RRI correct response rates.

Fig. 10 is a view showing an example of the seating surface of the seat of modification 1.

Fig. 11 is a perspective view showing an example of the appearance of the seat according to modification 2.

Detailed Description

Hereinafter, an embodiment of the present disclosure will be described in detail.

[1. Structural example of seat ]

The seat 1 of the present embodiment will be described with reference to fig. 1 to 5. Fig. 1 is a perspective view showing an example of the external appearance of a seat 1. As shown in fig. 1, the directions of the front, rear, left, right, up and down, which are appropriately shown in the drawings of the present embodiment, coincide with the directions of the occupant (not shown) when viewed in a state of being seated on the seat 1.

As shown in fig. 1, the seat 1 has a seat cushion 11, a seat back 12, and a headrest 13. The seat cushion 11 constitutes a seat surface of the seat 1, and the seatback 12 and the headrest 13 constitute a back surface of the seat 1. The seat 1 is covered with a cover member 14 made of cloth, leather, vinyl leather, or the like, or a combination thereof.

The following describes a case where the seat 1 is provided to a moving body, but the present invention is not limited to this, and the seat may be provided in a place where the seat is not moved, such as a building. The case where the moving object is a vehicle is described, but the present invention is not limited to this, and may be a ship, an aircraft, or the like. The seat 1 is not limited to the structure provided in the driver's seat of the mobile body, and may be a structure provided in a guest seat of the mobile body.

The seat cushion 11 is mounted so that the upper surface side is covered with the cover member 14 for seating an occupant. The seat cushion 11 will be described with reference to fig. 2 and 3. Fig. 2 is a view showing an example of the seating surface of the seat 1. Fig. 3 is a view showing an example of a cross-sectional view in the direction III-III in fig. 2. As shown in fig. 2 and 3, the seat cushion 11 includes a main cushion 15 and a sub cushion 16.

The main cushion 15 is formed of expanded polyurethane foam as a flexible polyurethane foam. Fitting grooves 15D are formed in front and left and right side edges of the lower surface 15E of the main cushion 15, and the fitting grooves 15D are fitted to a seat cushion frame (not shown) having a substantially U-shape in a plan view in fig. 2. The main cushion 15 is supported by the seat cushion frame with fitting grooves 15D formed in the front edge portion and the left and right edge portions of the lower surface 15E fitted to the seat cushion frame.

The main cushion 15 receives the load of the seated occupant. A bottom recess 17 having a substantially rectangular shape in plan view is formed in a lower surface 15E of the main pad 15 on the opposite side of the upper surface to which the load of the seated person is applied, and opens downward. The sub-gasket 16 having a substantially rectangular shape in plan view is fitted into the recess 17 from below.

The sub-cushion 16 is formed of expanded polyurethane foam as a flexible polyurethane foam. The main pad 15 is supported by a plurality of springs 19 provided between right and left seat cushion frames (not shown) fitted in fitting grooves 15D provided in right and left side edges of the lower surface 15E in a state where the sub pad 16 is fitted in the recess 17.

As shown in fig. 2 and 3, the bottom surface 17A of the concave portion 17 is formed to include a first region 15A opposed to the left buttocks of the seated user seated on the periphery of the ischial portions of the main pad 15 and a second region 15B opposed to the right buttocks of the seated user. Therefore, the upper surface 16A of the sub-pad 16, which receives the load of the seated occupant, which faces and abuts the bottom surface 17A of the concave portion 17, is formed so as to face the first region 15A facing the left buttocks around the ischial portions of the seated occupant and the second region 15B facing the right buttocks around the ischial portions of the seated occupant.

The piezoelectric sensor 21 is a piezoelectric thin film sensor formed in an elongated shape, and is disposed inside the seat cushion 11. The piezoelectric sensor 21 senses a ballistocardiogram (BCG: ballisocardiology) of the seated person. The piezoelectric sensor 21 is a sensor that uses the piezoelectric effect of a piezoelectric element that generates a voltage when receiving a pressure. The signal representing the ballistocardiogram detected by the piezoelectric sensor 21 is supplied to the controller 25.

Specifically, the piezoelectric sensor 21 is disposed along the front-rear direction on the upper surface 16A of the sub-pad 16 fitted into the concave portion 17 so as to face the first region 15A facing the left buttocks around the ischial portions of the seated person. The piezoelectric sensor 21 is fixed to the upper surface 16A by an adhesive or the like. The wiring of the piezoelectric sensor 21 is led downward along the rear side surface of the sub-pad 16, and is electrically connected to the controller 25.

The controller 25 associated with the seat 1 refers to an electric signal, which is a sensing result supplied from the piezoelectric sensor 21, and measures the heartbeat of the occupant. The controller 25 determines whether or not a predetermined condition concerning the ballistocardiogram of the seated person is satisfied based on the sensing result of the piezoelectric sensor 21, and if it is determined that the predetermined condition is satisfied, performs processing for outputting a signal for notifying the user.

As shown in fig. 2 and 3, the sandwiching member 23 is interposed between the piezoelectric sensor 21 and the bottom surface 17A of the recess 17 at the center portion in the longitudinal direction of the piezoelectric sensor 21, and is disposed so as to be capable of pressing a part of the piezoelectric sensor 21. For example, as shown in fig. 2, the sandwiching member 23 is disposed so that the positions of the distances from the front end and the rear end of the piezoelectric sensor 21 in the longitudinal direction by the length L1 substantially overlap with the central position in the front-rear direction of the lower surface 23A (see fig. 4) of the sandwiching member 23. That is, the center position in the longitudinal direction of the piezoelectric sensor 21 and the center position in the front-rear direction of the lower surface 23A of the sandwiching member 23 are disposed so as to substantially overlap.

The state in which the front end edge portion or the rear end edge portion of the lower surface 23A of the sandwiching member 23 is disposed in the vicinity of the center position in the longitudinal direction of the piezoelectric sensor 21 is also included in the state in which the sandwiching member 23 is disposed in the center position in the longitudinal direction of the piezoelectric sensor 21.

The sandwiching member 23 will be described with reference to fig. 4. Fig. 4 is a perspective view showing an example of the sandwiching member 23 fixed to the upper surface of the piezoelectric sensor 21. As shown in fig. 4, the sandwiching member 23 is made of a synthetic resin such as a thermosetting elastomer or a thermoplastic elastomer, or a metal such as aluminum or iron, and the lower surface 23A is formed in a planar shape, and the upper surface 23B is formed in a substantially spherical shape.

The lower surface 23A of the sandwiching member 23 has a length equal to or longer than the width L2 of the piezoelectric sensor 21, preferably a width L3 in the left-right direction which is equal to the width L2 of the piezoelectric sensor 21 in the direction orthogonal to the longitudinal direction. The lower surface 23A of the sandwiching member 23 has a length L4 in the front-rear direction substantially identical to the width L2 of the piezoelectric sensor 21 in the direction orthogonal to the longitudinal direction. The lower surface 23A of the sandwiching member 23 is formed in a substantially rectangular shape in plan view. The lower surface 23A of the sandwiching member 23 may be formed in a substantially circular or polygonal shape having a length equal to or longer than the width L2 of the piezoelectric sensor 21, preferably a diameter substantially equal to the width L2 of the piezoelectric sensor 21.

The lower surface 23A of the sandwiching member 23 is fixed to a surface of the piezoelectric sensor 21 facing the bottom surface 17A, that is, a central portion in the longitudinal direction of the upper surface of the piezoelectric sensor 21 by adhesion or the like. The height H1 of the sandwiching member 23 from the lower surface, that is, the height H1 from the piezoelectric sensor 21 to the apex of the upper surface 23B is formed to a predetermined height, for example, a height of about 3mm to about 15mm, which is a height that does not give a feeling of foreign matter to a seated person seated on the seat cushion 11.

Next, an example of the deformation state of the piezoelectric sensor 21 when the seated person sits on the upper surface of the seat cushion 11 will be described with reference to fig. 5. Fig. 5 is an enlarged view of the V portion in fig. 3, and shows an example of the deformation state of the piezoelectric sensor 21 before and after seating of the seated person. As shown in fig. 5, the pressing force from above does not act on the sandwiching member 23 via the main pad 15 before the sitting person sits. Therefore, the piezoelectric sensor 21 fixed to the upper surface 16A of the sub-pad 16 is not subjected to the pressing force from above in a substantially horizontal state, and thus the strain amount of the piezoelectric sensor 21 is substantially zero.

As shown in fig. 5, after seating of the occupant, the first region 15A of the main pad 15 facing the left buttocks of the occupant elastically deforms so as to protrude in a direction in which a load from the occupant acts, that is, in a downward direction. Therefore, the bottom surface 17A of the concave portion 17 formed on the lower surface 15E of the main pad 15 is also elastically deformed so that the portion facing the first region 15A protrudes downward.

The piezoelectric sensor 21 to which the sandwiching member 23 is fixed to the upper surface 16A of the sub-pad 16 in the front-rear direction so as to be in contact with a portion of the bottom surface 17A of the recess 17 facing the first region 15A via the sandwiching member 23. As a result, the portion of the sub-gasket 16 to which the piezoelectric sensor 21 is fixed elastically deforms so as to protrude downward from the position indicated by the one-dot chain line P1 according to the height of the sandwiching member 23. As a result, the piezoelectric sensor 21 is elastically deformed so as to extend further in the longitudinal direction, i.e., in the direction of the double-headed arrow 27 shown in fig. 5.

Therefore, by disposing the sandwiching member 23 at the center portion in the longitudinal direction of the piezoelectric sensor 21, the amount of strain of the piezoelectric sensor 21 due to the load of the occupant can be increased as compared with the amount of strain in the case where the sandwiching member 23 is not disposed. As a result, the output voltage output from the piezoelectric sensor 21 can be increased as compared with the case where the sandwiching member 23 is not interposed. Further, the sandwiching member 23 locally applies the load of the seated person to the central portion in the longitudinal direction of the piezoelectric sensor 21 over the entire width of the piezoelectric sensor 21, so that the amount of strain of the piezoelectric sensor 21 receiving the load of the seated person can be increased. As a result, the output voltage output from the piezoelectric sensor 21 can be further increased than in the case where the sandwiching member 23 is not disposed.

[ 2] Based on the effect of the seat 1 ]

[ Measurement example of signal waveform of ballistocardiogram ]

Next, the effect of the seat 1 will be described with reference to fig. 6 to 9. First, an example of a signal waveform for detecting a ballistocardiogram of a seated person seated in the seat 1 under a static condition in which an engine of a vehicle is stopped will be described with reference to fig. 6. Fig. 6 is a diagram showing an example of a signal waveform of a heart attack of a seated person sensed by the piezoelectric sensor 21 of the seat 1 in a state where the sandwiching member 23 is present and a state where the sandwiching member 23 is not present, respectively, in a static condition where the engine of the vehicle is stopped. The signal waveform of the ballistocardiogram detected by the piezoelectric sensor 21 is detected by a band-pass filter of 0.8Hz to 20 Hz.

As shown in an output waveform diagram 101 of fig. 6, in a state where the sandwiching member 23 is present in the longitudinal center portion of the piezoelectric sensor 21, for example, as shown by surrounding the respective longitudinal circles 28 and 29, a signal waveform having a sufficient output voltage of the piezoelectric sensor 21 is measured. On the other hand, as shown in the output waveform diagram 102 of fig. 6, in a state where the member 23 is not interposed at the center portion in the longitudinal direction of the piezoelectric sensor 21, a signal waveform in which the output voltage of the piezoelectric sensor 21 is low and separation from noise is difficult is measured.

Therefore, by disposing the sandwiching member 23 at the center portion in the longitudinal direction of the piezoelectric sensor 21, the amount of strain of the piezoelectric sensor 21 due to the load of the occupant can be increased as compared with the amount of strain in the case where the sandwiching member 23 is not disposed. As a result, the output voltage output from the piezoelectric sensor 21 can be increased as compared with the case where the sandwiching member 23 is not interposed, and a signal waveform of a ballistocardiogram having a sufficient output voltage can be obtained.

[ Measurement example of RRI estimation accuracy ]

Next, an example of the RRI estimation accuracy measured under the static condition in which the engine of the vehicle is stopped will be described with reference to fig. 7. Fig. 7 is a diagram showing an example of the ratio of RRI estimation accuracy obtained from the sensing result measured by the piezoelectric sensor 21 of the seat 1 in the state where the sandwiching member 23 is not present and the state where the sandwiching member 23 is present, respectively, under the static condition where the engine of the vehicle is stopped. Each rectangle in the graph of fig. 7 represents the upper 75% to 25% of the RRI estimation accuracy, and the horizontal line in the rectangle represents the central value of the RRI estimation accuracy. The line extending up and down of each rectangle represents a range from the maximum value to the minimum value of RRI estimation accuracy.

As shown in the estimation accuracy measurement chart 103 of fig. 7, the output voltage of the piezoelectric sensor 21 of the seat 1 is low in a state where the sandwiching member 23 is not present in the center portion in the longitudinal direction of the piezoelectric sensor 21, and the ratio of RRI estimation accuracy is about 0.7 to about 0.8. On the other hand, as shown in the estimation accuracy measurement chart 104 of fig. 7, in a state where the sandwiching member 23 is present in the longitudinal center portion of the piezoelectric sensor 21, the output voltage of the piezoelectric sensor 21 of the seat 1 becomes high, and the ratio of RRI estimation accuracy is about 0.97 to about 1.0. Therefore, by disposing the sandwiching member 23 at the center in the longitudinal direction of the piezoelectric sensor 21, the proportion of RRI estimation accuracy in the static condition in which the engine of the vehicle is stopped increases by about 13%.

Next, an example of the RRI estimation accuracy measured under dynamic conditions in which the vehicle travels at 80km per hour will be described with reference to fig. 8. Fig. 8 is a diagram showing an example of the ratio of RRI estimation accuracy obtained from the sensing detection result measured by the piezoelectric sensor 21 of the seat 1 in the state where the sandwiching member 23 is not present and the state where the sandwiching member 23 is present, respectively, under the dynamic condition that the vehicle runs at 80km per hour. Each rectangle in the graph of fig. 8 represents the upper 75% to 25% of the RRI estimation accuracy, and the horizontal line in the rectangle represents the central value of the RRI estimation accuracy. The line extending up and down of each rectangle represents a range from the maximum value to the minimum value of RRI estimation accuracy.

As shown in the estimation accuracy measurement chart 105 of fig. 8, the output voltage of the piezoelectric sensor 21 of the seat 1 is low in a state where the sandwiching member 23 is not present in the center portion in the longitudinal direction of the piezoelectric sensor 21, and the ratio of RRI estimation accuracy is about 0.1 to about 0.3. On the other hand, as shown in the estimation accuracy measurement chart 106 of fig. 8, in a state where the sandwiching member 23 is present in the longitudinal center portion of the piezoelectric sensor 21, the output voltage of the piezoelectric sensor 21 of the seat 1 becomes high, and the ratio of RRI estimation accuracy is about 0.45 to about 0.7. Therefore, by disposing the sandwiching member 23 at the center portion in the longitudinal direction of the piezoelectric sensor 21, the proportion of RRI estimation accuracy in the dynamic condition in which the vehicle runs at 80km per hour increases by about 42%.

Therefore, as shown in fig. 7 and 8, by disposing the sandwiching member 23 at the center in the longitudinal direction of the piezoelectric sensor 21, RRI estimation accuracy can be improved. In addition, the higher the RRI estimation accuracy is, the higher the RRI correct answer rate is. That is, by disposing the sandwiching member 23 at the center in the longitudinal direction of the piezoelectric sensor 21, the RRI correct response rate can be improved.

[ Description of RRI correct answer Rate ]

The foregoing "RRI correct answer rate" will be described based on fig. 9. Fig. 9 is a diagram illustrating an example of a distribution chart of RRI correct response rates. The horizontal axis of fig. 9 shows the ratio of the RRIs to the average value of RRIs (R-R INTERVAL: R-R intervals) of the ballistocarditis in a predetermined period (referred to as "average RRI" in fig. 9), and the vertical axis shows the number of times the ratio is obtained. In another aspect, FIG. 9 shows a distribution of "RRI/mean (RRI)". Here, "mean (RRI)" of the denominator refers to an average value of RRIs in a predetermined period, and "RRI" of the numerator refers to a value of each RRI to be a target. The predetermined time is not limited to a specific time, and may be, for example, 5 minutes or 30 minutes.

When the ratio is in the vicinity of 1, the value of the RRI to be the target is close to the average value, and thus the reliability is high, and when the ratio is greatly different from 1, the reliability of the value of the RRI to be the target is low. In measurement of the heartbeat, the measurement accuracy can be improved by excluding or adjusting the value of RRI of a value with low reliability.

The RRI correct answer rate is a ratio at which the RRI measured during a predetermined period is within a predetermined range. In general, the predetermined range defines a certain range centered on 1 of the ratio. In fig. 9, the frame 31 is an example of the predetermined range, and the ratio is in the range of 0.95 to 1.05.

For example, in fig. 9, an RRI correct answer rate of 50% means that the ratio corresponding to the number of times of 50% of RRIs measured during a prescribed period converges to the range of block 31.

In addition, when calculating the heartbeat of the occupant, the controller 25 may directly use the value of the RRI to be measured if the value of the RRI is within the predetermined range, or may use the value of the RRI measured most recently if the RRI to be measured is outside the predetermined range.

Alternatively, the ratio used in the case where the controller 25 calculates the RRI correct answer rate may be a ratio of the RRI measured at this time to the RRI measured at the latest. In this configuration, the distribution diagram corresponding to FIG. 9 shows the distribution of "RRI (k)/RRI (k-1)". Here, "RRI (k-1)" of the denominator means the value of the RRI measured at the kth-1 th time which is the nearest to the kth time, and "RRI (k)" of the numerator means the value of the RRI measured at the kth time.

Further, as the value of RRI used for calculation of the heartbeat, the controller 25 may use a new estimated value x (k) calculated by the following formula using the measured value y (k) of RRI of this time and the latest estimated value x (k-1),

x(k)＝w*y(k)+(1-w)*x(k-1)。

Here, w is a weight coefficient corresponding to a variance value or the like in the distribution map, and may be a value equal to or greater than 0 and equal to or less than 1. The value of the initial value x (0) that is the basis of the estimated value x may be calculated by the controller 25 by, for example, cepstrum analysis. The controller 25 may reset the value of the initial value x (0) every time the main power supply of the vehicle (mobile unit) is started, or may reset the value every predetermined period.

When the heartbeat of the occupant calculated based on the sensing result of the piezoelectric sensor 21 indicates that an abnormality has occurred in the occupant, the controller 25 performs a predetermined process (hereinafter, simply referred to as "predetermined process") such as a process of notifying the occupant of the abnormality. In a broad sense, the controller 25 performs the predetermined process when the sensing detection result of the piezoelectric sensor 21 satisfies a predetermined condition concerning the ballistocardiogram of the occupant. Here, the sensing result of the piezoelectric sensor 21 may be, for example, a case where the number of heartbeats of the seated person within a predetermined time is equal to or less than a lower limit value or equal to or greater than an upper limit value, or a case where the number of heartbeats is equal to or greater than a reference value.

As the predetermined process, the controller 25 may perform the following exemplary process accompanied by the output of a signal for notifying information on the state of the occupant:

Processing to output sound, image, light, or text in order to notify the occupant of drowsiness, excitement, fatigue, or the like;

A process of outputting a control signal to operate a seat or another movable part of the movable body in order to notify the occupant of drowsiness, excitement, fatigue, or the like;

And a process of transmitting information indicating that an abnormality has occurred in the seated person to a predetermined contact destination by radio communication or the like.

As the predetermined process, the controller 25 may perform the following exemplary process related to the movement of the vehicle:

a process of stopping the vehicle on a road shoulder or the like;

A process of reducing the speed of the vehicle;

A process of moving the vehicle to a predetermined place such as a hospital or a home.

In addition, when a predetermined condition concerning the ballistocardiogram of the occupant is satisfied, the controller 25 may perform, as the predetermined process, both the process of outputting a signal for notifying information concerning the state of the occupant and the process concerning the movement of the vehicle (moving body).

[3. Modification ]

A modification of the above embodiment will be described. In the following description, for convenience of description, members having the same functions as those described in the above-described embodiments are given the same reference numerals, and the description thereof is not repeated.

Modification 1

The seat cushion 11 of the seat 41 of modification 1 will be described with reference to fig. 10. Fig. 10 is a view showing an example of the seating surface of the seat 41 of modification 1. The seat 41 has substantially the same structure as the seat 1 of the above embodiment. However, as shown in fig. 10, the seat cushion 11 may have a plurality of piezoelectric sensors 21, for example, two piezoelectric sensors 21, arranged in parallel in the left-right direction on the upper surface 16A of the sub cushion 16 fitted into the recess 17 formed in the lower surface 15E of the main cushion 15.

The piezoelectric sensors 21 are disposed along the front-rear direction of the seat cushion 11. Each piezoelectric sensor 21 is fixed to the upper surface 16A of the sub-pad 16 by adhesion or the like so as to face the first region 15A facing the left buttocks around the ischial portions of the seated person.

The wiring of each piezoelectric sensor 21 is led downward along the rear side surface of the sub-pad 16, and is electrically connected to the controller 25. The piezoelectric sensors 21 are not limited to the first region 15A facing the left buttocks around the ischial portions of the seated person, and may be arranged side by side in the left-right direction so as to face the second region 15B facing the right buttocks around the ischial portions of the seated person, and may be fixed to the upper surface 16A by an adhesive or the like.

In addition, at the central portion in the longitudinal direction of each piezoelectric sensor 21, an sandwiching member 23 is interposed between each piezoelectric sensor 21 and the bottom surface 17A of the recess 17, and is arranged so as to be able to press a part of each piezoelectric sensor 21. The planar lower surface 23A of each sandwiching member 23 is fixed by adhesion or the like to the surface of each piezoelectric sensor 21 facing the bottom surface 17A of the recess 17, that is, the center portion in the longitudinal direction of the upper surface of each piezoelectric sensor 21. The height of each sandwiching member 23 from the lower surface 23A, that is, the height from the piezoelectric sensor 21 to the apex of the upper surface 23B of each sandwiching member 23 is formed to be substantially the same predetermined height. For example, the height of each of the sandwiching members 23 from the apex of the lower surface 23A to the upper surface 23B is formed to be about 3mm to about 15mm in height, which does not give a feeling of foreign matter to the seated person sitting on the seat cushion 11.

The seat 41 configured as described above can provide substantially the same effects as the seat 1 of the above embodiment. The controller 25 can use the signal waveform of the heart attack having the largest amplitude from the signal waveforms (BCG waveforms) of the heart attack of the occupant outputted from the piezoelectric sensors 21, and can further improve the RRI accurate response rate.

Modification 2

The seat 51 of modification 2 will be described with reference to fig. 11. Fig. 11 is a perspective view showing an example of the appearance of the seat 51 according to modification 2. The seat 51 has substantially the same structure as the seat 1 of the above embodiment. However, as shown in fig. 11, the seat back 12 may also be provided with a main cushion 52, a sub cushion 16, a piezoelectric sensor 21, and an sandwiching member 23. The seat back 12 is attached so as to cover the cover member 14.

The main cushion 52 is formed of a soft polyurethane foam, that is, a foamed polyurethane foam, similarly to the main cushion 15. A bottom concave portion 17 having a substantially rectangular front view is formed in a rear surface of the main cushion 52 opposite to a front surface receiving a load from a lumbar region of a seated person so as to open rearward. The sub-gasket 16 having a substantially rectangular shape in front view is fitted into the recess 17 from the rear. The bottom surface 17A of the recess 17 is formed to include: a third region 53 opposite to the left waist portion seated against the periphery of the ischial portion of the seated person of the main pad 15; and a fourth region 54 opposed to the right waist portion of the seated user's ischial portion periphery.

Therefore, the upper surface 16A of the sub-pad 16 facing the bottom surface 17A of the concave portion 17, which receives the load of the seated occupant, is formed so as to face the third region 53 facing the left lumbar region of the ischial portion periphery of the seated occupant and the fourth region 54 facing the right lumbar region of the ischial portion periphery of the seated occupant.

The elongated piezoelectric sensor 21 is disposed on the upper surface 16A of the sub-pad 16 fitted into the concave portion 17 so as to face the third region 53 facing the left waist portion around the ischial portion of the occupant in the up-down direction, and is fixed to the upper surface 16A by an adhesive or the like. The wiring of the piezoelectric sensor 21 is led out rearward along the lower side surface of the sub-pad 16, and is electrically connected to the controller 25. The piezoelectric sensor 21 is not limited to the third region 53 facing the left waist portion around the ischial portions of the seated person, and may be disposed so as to face the fourth region 54 facing the right waist portion around the ischial portions of the seated person in the up-down direction and fixed to the upper surface 16A by an adhesive or the like.

In addition, at the central portion in the longitudinal direction of the piezoelectric sensor 21, the sandwiching member 23 is interposed between the piezoelectric sensor 21 and the bottom surface 17A of the recess 17, and is arranged so as to be able to press a part of the piezoelectric sensor 21. The lower surface 23A of the sandwiching member 23 is fixed to a surface of the piezoelectric sensor 21 facing the bottom surface 17A of the recess 17, that is, a central portion in the longitudinal direction of the piezoelectric sensor 21 by adhesion or the like. The height of the sandwiching member 23 from the lower surface 23A, that is, the height from the piezoelectric sensor 21 to the apex of the upper surface 23B of the sandwiching member 23 is formed to be a predetermined height. For example, the height from the lower surface of each sandwiching member 23 to the apex of the upper surface 23B of the sandwiching member 23 is formed, for example, to a height of about 3mm to about 15mm, and is formed to a height that does not give a feeling of foreign matter to a seated person sitting on and leaning against the seat back 12.

Therefore, by disposing the sandwiching member 23 at the center portion in the longitudinal direction of the piezoelectric sensor 21, the amount of strain of the piezoelectric sensor 21 due to the pressing force of the left waist of the occupant leaning on the seat back 12 increases as compared with the amount of strain in the case where the sandwiching member 23 is not disposed. As a result, the output voltage outputted from the piezoelectric sensor 21 can be made larger than in the case where the sandwiching member 23 is not interposed, and a signal waveform of a ballistocardiogram having a sufficient output voltage can be obtained.

Modification 3

For example, the seat back 12 of the seat 51 shown in fig. 11 may have a plurality of piezoelectric sensors 21, for example, two piezoelectric sensors 21, arranged in parallel in the left-right direction on the upper surface 16A of the sub cushion 16. The piezoelectric sensors 21 are arranged along the up-down direction of the seat back 12. Each piezoelectric sensor 21 is fixed to the upper surface 16A of the sub-pad 16 by adhesion or the like so as to face the third region 53 facing the left waist portion around the ischial portion of the occupant.

The wiring of each piezoelectric sensor 21 is led out rearward along the lower side surface of the sub-pad 16, and is electrically connected to the controller 25. The piezoelectric sensors 21 are not limited to the third region 53 facing the left waist portion around the ischial portions of the seated person, and may be arranged side by side in the left-right direction so as to face the fourth region 54 facing the right waist portion around the ischial portions of the seated person, and may be fixed to the upper surface 16A by an adhesive or the like.

In addition, at the central portion in the longitudinal direction of each piezoelectric sensor 21, an sandwiching member 23 is interposed between each piezoelectric sensor 21 and the bottom surface 17A of the recess 17, and is arranged so as to be able to press a part of each piezoelectric sensor 21. The planar lower surface 23A of each sandwiching member 23 is fixed by adhesion or the like to a surface of each piezoelectric sensor 21 facing the bottom surface 17A of the recess 17, that is, a central portion in the longitudinal direction of each piezoelectric sensor 21. The height of each sandwiching member 23 from the lower surface 23A, that is, the height from the piezoelectric sensor 21 to the apex of the upper surface 23B is set to a predetermined height, for example, a height of about 3mm to about 15mm, and is set to a height such that a seated person sitting on the seat back 12 does not feel a foreign body sensation.

The seat of modification 3 configured as described above can exert substantially the same effects as the seat 51 of modification 2. The controller 25 can use the signal waveform of the ballistocardiogram having the largest amplitude from the signal waveforms of the ballistocardiogram of the occupant outputted from the piezoelectric sensors 21, and can further improve the RRI accurate response rate.

Modification 4

For example, the upper surface 23B of the sandwiching member 23 may be integrally provided by being fixed to the bottom surface 17A of the concave portion 17 of the insert sub-gasket 16 by adhesion or the like. For example, a spherical recess may be formed in the bottom surface 17A of the recess 17, and the upper surface 23B of the sandwiching member 23 may be fitted into the recess and fixed by adhesion or the like. For example, a convex portion may be formed on the bottom surface 17A of the concave portion 17, and a concave portion into which the convex portion is fitted may be formed on the upper surface 23B of the sandwiching member 23. Further, the convex portion formed on the bottom surface 17A may be fitted into the concave portion formed on the upper surface 23B of the sandwiching member 23, and may be fixed by adhesion or the like.

In this case, the upper surface 23B of the sandwiching member 23 is fixed to a position facing the center portion in the longitudinal direction of the piezoelectric sensor 21 at the bottom surface 17A of the recess 17, and the piezoelectric sensor 21 is fixed to the upper surface 16A of the sub-pad 16 fitted into the recess 17. Thus, the sandwiching member 23 is integrally provided on the bottom surface 17A of the recess 17 of the main pad 15, and therefore, man-hours at the time of assembling the seat 1 can be reduced.

[ Notes ]

The present disclosure is not limited to the above-described embodiments, and various modifications can be made within the scope indicated by the scope of the claims, and embodiments in which technical means disclosed in the different embodiments are appropriately combined are also included in the technical scope of the present disclosure.

[ Additionally remembered ]

The seat according to embodiment 1 of the present disclosure includes: a main pad for receiving a load of a seated person; a sub-pad fitted in a recess formed in a surface of the main pad opposite to a surface receiving the load; a piezoelectric sensor disposed on a surface of the sub-pad that receives the load, and configured to sense and detect a ballistocardiogram of the seated person; and an sandwiching member that is raised from the piezoelectric sensor by a predetermined height, and is interposed between the piezoelectric sensor and a bottom surface of the recess facing the piezoelectric sensor, and is configured to be capable of pressing a part of the piezoelectric sensor.

According to the above configuration, the main pad presses a part of the piezoelectric sensor via the sandwiching member having a predetermined height, and the load of the occupant is applied. This can increase the strain amount of the piezoelectric sensor due to the load of the occupant as compared with the strain amount in the case where the sandwiching member is not disposed.

In the seat according to aspect 2 of the present disclosure, in aspect 1, the piezoelectric sensor is elongated, and the sandwiching member is disposed at a central portion in a longitudinal direction of the piezoelectric sensor.

According to the above configuration, the sandwiching member is disposed at the center portion in the longitudinal direction of the piezoelectric sensor, and therefore the piezoelectric sensor can be locally pressed, whereby the strain amount of the piezoelectric sensor receiving the load of the seated person can be increased.

In the seat according to aspect 3 of the present disclosure, in aspect 2 above, a dimension of the sandwiching member in a direction orthogonal to the longitudinal direction of the piezoelectric sensor is formed to be equal to or greater than a width of the piezoelectric sensor in a short side direction.

According to the above configuration, the sandwiching member presses the longitudinal center portion of the piezoelectric sensor over the entire width in the short side direction, so that the strain amount of the piezoelectric sensor receiving the load of the seated person can be increased.

In the seat according to aspect 4 of the present disclosure, in the above aspect 2 or 3, the main pad and the sub pad are included in a seat pad constituting a seat surface, the piezoelectric sensor is disposed along a front-rear direction of the seat pad, and the piezoelectric sensor is disposed such that the central portion in the longitudinal direction of the piezoelectric sensor is opposed to at least one of left buttocks and right buttocks of the seated person seated on the seat pad.

According to the above configuration, the elongated piezoelectric sensor is disposed along the front-rear direction of the seat cushion, and is disposed such that the central portion in the longitudinal direction faces at least one of the left hip or the right hip of the seated person. This can suppress variations in sensitivity of the piezoelectric sensor due to the posture and seating position of the seated person. Further, since the load applied to the piezoelectric sensor from the left hip or the right hip is larger than the load applied to the piezoelectric sensor from the left thigh or the right thigh, the strain amount of the piezoelectric sensor can be increased. As a result, the amplitude of the ballistocardiographic waveform of the seated person output from the piezoelectric sensor can be increased.

In addition, in the seat according to aspect 5 of the present disclosure, in aspect 4, a plurality of piezoelectric sensors are arranged in parallel in the left-right direction of the seat cushion.

According to the above configuration, since the plurality of piezoelectric sensors are arranged in parallel in the left-right direction of the seat cushion, the ballistocardiogram of the occupant having the largest amplitude can be used as the ballistocardiogram outputted from each piezoelectric sensor.

In addition, in the seat according to embodiment 6 of the present disclosure, in the above-described embodiment 1 or 2, the sandwiching member is fixed to the piezoelectric sensor.

According to the above configuration, the sandwiching member is fixed to the piezoelectric sensor, so that the sandwiching member can be prevented from being lost when the seat is assembled.

In addition, in the seat according to aspect 7 of the present disclosure, in aspect 6, the sandwiching member is made of synthetic resin or metal, a lower surface is formed in a planar shape, and an upper surface is formed in a spherical shape.

According to the above configuration, the sandwiching member is made of synthetic resin or metal, and the lower surface is formed in a flat shape, so that the sandwiching member can be easily fixed to the piezoelectric sensor by adhesion or the like. Further, since the upper surface of the sandwiching member is formed in a spherical shape, abrasion of the main gasket can be prevented, and a long life of the main gasket can be achieved.

In addition, in the seat according to embodiment 8 of the present disclosure, in embodiment 1 or 2, the sandwiching member is integrally provided on the bottom surface of the concave portion.

According to the above configuration, the sandwiching member is integrally provided on the bottom surface of the concave portion of the main pad, so that man-hours at the time of assembling the seat can be reduced.

In the seat according to aspect 9 of the present disclosure, in the aspect 2 or 3, the main cushion and the sub cushion are included in a seat back that is a backrest, the piezoelectric sensor is disposed along a vertical direction of the seat back, and the piezoelectric sensor is disposed such that the central portion in the longitudinal direction of the piezoelectric sensor is opposed to at least one of a left lumbar region and a right lumbar region of the seated occupant.

According to the above configuration, the elongated piezoelectric sensor is disposed along the up-down direction of the seat back, and the center portion in the longitudinal direction is disposed so as to face at least one of the left lumbar region and the right lumbar region of the occupant. This can suppress variations in sensitivity of the piezoelectric sensor due to the posture and seating position of the seated person. In addition, the load applied to the piezoelectric sensor from the left waist portion or the right waist portion can increase the strain amount of the piezoelectric sensor. As a result, the amplitude of the ballistocardiographic waveform of the seated person output from the piezoelectric sensor can be increased.

In addition, in the seat according to aspect 10 of the present disclosure, in aspect 9, a plurality of piezoelectric sensors are arranged in parallel in the left-right direction of the seat back.

According to the above configuration, since the plurality of piezoelectric sensors are arranged in parallel in the left-right direction of the seat back, the heart-beat waveform having the largest amplitude can be used as the heart-beat waveform of the occupant outputted from each piezoelectric sensor.

Description of the reference numerals

1. 41, 51 Seat, 11 seat cushion, 12 seat back, 15, 52 primary cushion, 15A first region, 15B second region, 16 secondary cushion, 16A upper surface, 17 recess, 17A bottom surface, 21 piezoelectric sensor, 23 sandwiching member, 53 third region, 54 fourth region.

Claims (10)

1. A seat is provided with:

a main pad for receiving a load of a seated person;

A sub-pad fitted in a recess formed in a surface of the main pad opposite to a surface receiving the load;

a piezoelectric sensor disposed on a surface of the sub-pad that receives the load, and configured to sense and detect a ballistocardiogram of the seated person; and

An sandwiching member, which is raised from the piezoelectric sensor by a predetermined height, is interposed between the piezoelectric sensor and a bottom surface of the recess facing the piezoelectric sensor, and is configured to be able to press a part of the piezoelectric sensor.

2. The seat according to claim 1, wherein,

The piezoelectric sensor is in a strip shape,

The sandwiching member is disposed at a central portion in a longitudinal direction of the piezoelectric sensor.

3. The seat according to claim 2, wherein,

The dimension of the sandwiching member in a direction orthogonal to the longitudinal direction of the piezoelectric sensor is formed to be equal to or greater than the width of the piezoelectric sensor in the short side direction.

4. A seat according to claim 2 or 3, wherein,

The primary cushion and the secondary cushion are included in a seat cushion that forms a seating surface,

The piezoelectric sensor is disposed along a front-rear direction of the seat cushion,

The piezoelectric sensor is disposed such that the central portion in the longitudinal direction of the piezoelectric sensor faces at least one of left and right buttocks of the seated person seated on the seat cushion.

5. The seat according to claim 4, wherein,

The piezoelectric sensors are arranged in parallel in the left-right direction of the seat cushion.

6. The seat according to claim 1 or 2, wherein,

The sandwiching member is fixed to the piezoelectric sensor.

7. The seat according to claim 6, wherein,

The sandwiching member is made of synthetic resin or metal, and has a planar lower surface and a spherical upper surface.

8. The seat according to claim 1 or 2, wherein,

The sandwiching member is integrally provided on the bottom surface of the recess.

9. A seat according to claim 2 or 3, wherein,

The primary cushion and the secondary cushion are included in a seat back that becomes a backrest,

The piezoelectric sensor is disposed along the up-down direction of the seatback,

The piezoelectric sensor is disposed such that the central portion in the longitudinal direction of the piezoelectric sensor faces at least one of a left waist portion and a right waist portion of the seated occupant.

10. The seat according to claim 9, wherein,

The piezoelectric sensors are arranged in parallel in the left-right direction of the seat back.