Vehicle seats

Abstract

To provide a vehicle seat capable of acquiring highly reliable biological information.SOLUTION: A vehicle seat includes: a seat body having a seat cushion and a seat back; and a pressure sensor for detecting ballistocardiogram of a seated person. The seat body has a high rigidity part where hardness in a thickness direction is larger than that of the other part. The pressure sensor is arranged in the high rigidity part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to vehicle seats. [Background technology]

[0002] A vehicle seat configured to acquire an electrocardiogram signal as bioinformation of a seated occupant is known (see Patent Document 1). In this vehicle seat, the electrocardiogram signal is calculated based on an electrical signal of the seated occupant detected by a capacitance sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-220322 A Summary of the Invention [Problem to be solved by the invention]

[0004] The vehicle seat vibrates when the vehicle is moving. Therefore, noise caused by the vibration is superimposed on the output of the sensor installed in the vehicle seat. When the sensor output contains noise, the reliability of the acquired biometric information decreases.

[0005] An object of one aspect of the present disclosure is to provide a vehicle seat that can acquire highly reliable biological information. [Means for solving the problem]

[0006] One aspect of the present disclosure is a vehicle seat (1) including a seat body (2) having a seat cushion (3) and a seat back (4), and a pressure sensor (10) configured to detect ballistocardial movements of an occupant. The seat body (2) has a high-rigidity portion (22) that is harder in the thickness direction than other portions. The pressure sensor (10) is disposed in the high-rigidity portion (22).

[0007] According to this configuration, the pressure sensor 10 is disposed in the high rigidity portion 22, so that the vibration direction of the pressure sensor 10 is stabilized, and noise caused by vehicle vibrations and included in the output of the pressure sensor 10 is reduced, thereby making it possible to obtain highly reliable bioinformation based on ballistocardiogram.

[0008] In one aspect of the present disclosure, the high rigidity portion (22) may include a part of the elastic seat pad (31), and a reinforcing member (32) that is disposed on any one of the front surface of the seat pad (31) that supports a seated occupant, the back surface of the seat pad (31) opposite the front surface, or inside the seat pad (31) and has a higher rigidity than the seat pad (31). With this configuration, it is possible to provide the seat body (2) with a high rigidity portion (22) that is suitable for arranging the pressure sensor (10) while suppressing a decrease in the comfort of sitting on the seat body (2).

[0009] In one aspect of the present disclosure, the reinforcing member (32) may be disposed on the surface of the seat pad (31). The pressure sensor (10) may be disposed overlapping the reinforcing member (32) so as to sandwich the reinforcing member (32) together with the seat pad (31). This configuration improves the stability of the vibration direction of the pressure sensor (10). This can increase the reliability of the biometric information.

[0010] In one aspect of the present disclosure, the reinforcing member 32 may be disposed on the back surface of the seat pad 31 or inside the seat pad 31. This configuration can help prevent deterioration of the sitting comfort in the high rigidity portion 22.

[0011] Note that the symbols in the above parentheses are examples showing the correspondence with the specific configurations etc. described in the embodiments described below, and the present disclosure is not limited to the specific configurations etc. shown by the symbols in the above parentheses. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing a vehicle seat according to an embodiment. [Diagram 2]2A is a schematic plan view showing the seat cushion and pressure sensors of FIG. 1, and FIG. 2B is a schematic view showing an example of the arrangement of pressure sensors in the high rigidity portion of FIG. 2A. [Diagram 3] 3A is a schematic cross-sectional view taken along line IIIA-IIIA in FIG. 2A, and FIGS. 3B, 3C, and 3D are schematic cross-sectional views showing examples of the arrangement of reinforcing members different from that in FIG. 3A. [Figure 4] FIG. 4 is a graph showing an example of an output signal of the pressure sensor. [Diagram 5] 5A, 5B, 5C, and 5D are schematic cross-sectional views showing examples of the arrangement of piezoelectric sensors in embodiments different from that in FIG. 2A. [Figure 6] FIG. 6 is a schematic diagram showing a vehicle seat in an embodiment different from that in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, embodiments to which the present disclosure is applied will be described with reference to the drawings. [1. First embodiment] [1-1. Configuration] The vehicle seat 1 shown in FIG.

[0014] The vehicle seat 1 of this embodiment is used as a seat for a passenger vehicle. Note that the directions in the following description and in each drawing refer to the directions in a state in which the vehicle seat 1 is assembled to a vehicle (i.e., a passenger vehicle). In this embodiment, the seat width direction coincides with the left-right direction of the vehicle, and the front of the seat coincides with the front of the vehicle.

[0015] <Seat body> The seat body 2 has a seat cushion 3 and a seat back 4. The seat cushion 3 is a portion for supporting the buttocks of a seated person P. The seat back 4 is a portion for supporting the back of the seated person P.

[0016] 2, the seat cushion 3 has a flexible portion 21 and a high rigidity portion 22. The high rigidity portion 22 is a portion of the seat cushion 3 that is harder than the flexible portion 21 in the thickness direction.

[0017] In this embodiment, the high rigidity portion 22 is provided in a range of the seat cushion 3 that supports the periphery of the thigh and ischium of the left leg of the seated person P. Note that the high rigidity portion 22 may be provided in a range that supports the periphery of the thigh and ischium of the right leg of the seated person P.

[0018] The "hardness in the thickness direction" is the magnitude of the load required to deform a certain amount in the thickness direction of the seat cushion 3. In other words, when a load (i.e., a compressive load) is applied to the seat cushion 3 in the thickness direction, the smaller the amount of deformation in the thickness direction, the greater the "hardness in the thickness direction."

[0019] An example of a method for measuring "hardness in the thickness direction" is explained below. First, the tip of the load cell is pressed against the measurement target area with a constant load, and the amount of change in thickness is measured. Next, the static spring constant (N / mm) is calculated by dividing the load (N) applied to the load cell by the amount of change in thickness (mm).

[0020] The magnitude of "thickness direction hardness" at multiple measurement target locations is determined by comparing the static spring constants when the same load (e.g., 10N±1N) is applied. The tip of the load is spherical, and its radius (SR) is, for example, 22.5 mm. The pressing speed of the load is, for example, 50 mm / min.

[0021] <Pressure sensor> The pressure sensor 10 is configured to detect ballistocardiogram (BCG) of the seated occupant P. The pressure sensor 10 is disposed in a high-rigidity portion 22 of the seat cushion 3.

[0022] The pressure sensor 10 detects vibrations due to ballistocardial movement of the seated occupant P as a change in pressure, and outputs the detected change as an electrical signal to a processing device such as an ECU (electronic control unit). As the pressure sensor 10, for example, a piezoelectric sensor using a known strain gauge can be used.

[0023] In the present disclosure, the pressure sensor 10 is disposed in the high rigidity portion 22, so that the noise in the output of the pressure sensor 10 caused by the vibration of the vehicle is reduced, but the superposition of the noise itself is unavoidable. Therefore, the processing device performs a noise removal process on the output of the pressure sensor 10.

[0024] The processing device extracts a ballistocardiogram waveform by using, for example, a vibration output detected by an acceleration sensor installed in the vehicle and assuming linearity of the noise, removing noise from the output of the pressure sensor 10. The processing device estimates an RRI (RR-Interval) representing the heart rate variability of the seated occupant P from the extracted ballistocardiogram waveform.

[0025] As shown in Fig. 2B, a plurality of pressure sensors 10 may be disposed in the high rigidity portion 22. In the example shown in Fig. 2B, a plurality of pressure sensors 10 are arranged side by side in the front-rear direction (specifically, along the extension direction of the legs of the seated person P).

[0026] <Configuration of high rigidity part> As shown in FIG. 3A, the high rigidity portion 22 of the seat cushion 3 includes a part of the seat pad 31 and a reinforcing member 32.

[0027] The seat pad 31 is made of an elastic resin such as urethane. The reinforcing member 32 is a member having greater rigidity than the seat pad 31. The reinforcing member 32 is made of a hard resin such as acrylic, metal, etc. By arranging the reinforcing member 32 overlapping the seat pad 31 in the thickness direction of the seat cushion 3, the hardness of the seat cushion 3 in the thickness direction becomes greater than other portions (i.e., portions where the reinforcing member 32 is not arranged).

[0028] On the other hand, the flexible portion 21 of the seat cushion 3 does not have the reinforcing member 32. In other words, the flexible portion 21 is a portion of the seat cushion 3 where the reinforcing member 32 is not disposed so as to overlap the seat pad 31.

[0029] In this embodiment, the reinforcing member 32 is plate-shaped and is disposed on the surface of the seat pad 31 that supports the seated occupant P (i.e., the upper surface of the seat pad 31). The pressure sensor 10 is disposed overlapping the reinforcing member 32 so as to sandwich the reinforcing member 32 together with the seat pad 31. Specifically, the pressure sensor 10 is fixed to the surface of the reinforcing member 32 opposite to the seat pad 31.

[0030] With this configuration, the pressure sensor 10 is disposed closer to the seated occupant P than the reinforcing member 32, improving the stability of the vibration direction of the pressure sensor 10. As a result, noise contained in the output of the pressure sensor 10 is reduced, and the reliability of the biometric information acquired from the seated occupant P is improved.

[0031] The seat cushion 3 has a seat cover (not shown) that covers the seat pad 31 from above. Therefore, the pressure sensor 10, together with the seat pad 31, is also covered by the seat cover.

[0032] In the manufacturing process of the vehicle seat 1, the pressure sensor 10 may be attached to the reinforcing member 32 that is fixed in advance to the seat pad 31. Also, the pressure sensor 10 to which the reinforcing member 32 is attached in advance may be attached to the surface of the seat pad 31.

[0033] 3B, the reinforcing member 32 may be disposed on the back surface of the seat pad 31 opposite to the front surface (i.e., the underside of the seat pad 31). In this case, the pressure sensor 10 is disposed directly on the front surface of the seat pad 31.

[0034] 3C, the reinforcing member 32 may be disposed inside the seat pad 31 (i.e., between the upper and lower surfaces of the seat pad 31). In this case, the pressure sensor 10 is also disposed directly on the surface of the seat pad 31.

[0035] Furthermore, the reinforcing member 32 may be a block material having a certain thickness embedded in the vicinity of the rear surface of the seat pad 31, as shown in FIG. 3D.

[0036] 3B, 3C, and 3D, the reinforcing member 32 is disposed away from the surface of the seat pad 31, so that deterioration in the sitting comfort of the seat cushion 3 in the high rigidity portion 22 can be suppressed.

[0037] 4 is a graph showing a comparison of output signals when a pressure sensor is placed in a flexible portion and when the pressure sensor is placed in a high-rigidity portion in the same vehicle seat. The output signal S2 of the pressure sensor placed in the high-rigidity portion has a smaller amplitude than the output signal S1 of the pressure sensor placed in the flexible portion. This is because the vibrations in the front-back and left-right directions of the seat in the high-rigidity portion are suppressed, and the vibration direction is stabilized in the up-down direction.

[0038] It is sufficient that the pressure sensor 10 is disposed at least in the high rigidity portion 22. Therefore, a part of the pressure sensor 10 may be disposed in the flexible portion 21. However, from the viewpoint of enhancing the noise reduction effect, it is preferable that the entire pressure sensor 10 is disposed in the high rigidity portion 22.

[0039] [1-2. Effects] According to the embodiment described above in detail, the following effects can be obtained. (1a) By disposing the pressure sensor 10 in the high-rigidity portion 22, the vibration direction of the pressure sensor 10 is stabilized, and noise caused by vehicle vibrations included in the output of the pressure sensor 10 is reduced. Therefore, highly reliable bioinformation based on ballistocardiogram can be obtained.

[0040] (1b) By arranging the reinforcing member 32 in the seat pad 31, it is possible to provide the seat body 2 with a high rigidity portion 22 suitable for arranging the pressure sensor 10 while suppressing deterioration in the comfort of sitting on the seat body 2.

[0041] 2. Other embodiments Although the embodiments of the present disclosure have been described above, it goes without saying that the present disclosure is not limited to the above-described embodiments and can take various forms.

[0042] (2a) In the vehicle seat of the above embodiment, the pressure sensor does not necessarily have to be disposed on the surface of the seat pad or the reinforcing member. For example, as shown in Figures 5A and 5B, the pressure sensor 10 may be disposed inside or on the back surface of the seat pad 31. Furthermore, as shown in Figures 5C and 5D, a plurality of pressure sensors 10 may be disposed side by side in the thickness direction of the seat pad 31.

[0043] (2b) In the vehicle seat of the above embodiment, the high stiffness portion does not necessarily have to include a reinforcing member. For example, the high stiffness portion may be provided in the seat pad by changing the material of a part of the seat pad (i.e., by hardening the material).

[0044] (2c) In the vehicle seat of the above embodiment, as shown in Fig. 6, the pressure sensor 10 may be disposed in a high rigidity portion provided in the seat back 4. The high rigidity portion of the seat back 4 is provided in an area overlapping with the chest (particularly the left chest) of the seated occupant P. Moreover, the pressure sensor may be disposed in each of the high rigidity portions of the seat cushion and the seat back.

[0045] (2d) The vehicle seat of the above embodiment can be applied not only to the seats used in the above-mentioned automobiles, but also to seats used in vehicles other than automobiles, such as railway cars, ships, and aircraft.

[0046] (2e) The function of one component in the above embodiments may be distributed among multiple components, or the functions of multiple components may be integrated into one component. In addition, a part of the configuration of the above embodiments may be omitted. In addition, at least a part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. Note that all aspects included in the technical idea identified from the wording of the claims are embodiments of the present disclosure. [Explanation of symbols]

[0047] 1...vehicle seat, 2...seat body, 3...seat cushion, 4...seat back, 10: pressure sensor; 21: flexible part; 22: high rigidity part; 31: seat pad; 32...Reinforcing member.

Claims

1. a seat body having a seat cushion and a seat back; a pressure sensor configured to detect ballistocardial activity of the seated occupant; Equipped with The sheet body has a high-rigidity portion having a higher stiffness in a thickness direction than other portions, The high rigidity portion is A portion of a seat pad having elasticity; A reinforcing member that is disposed on any one of a surface of the seat pad that supports the seated occupant, a back surface of the seat pad opposite to the surface, and an interior of the seat pad and has a rigidity greater than that of the seat pad; Including, The pressure sensor is disposed in the high rigidity portion so as to sandwich at least a portion of the portion of the seat pad included in the high rigidity portion together with the reinforcing member.

2. 2. The vehicle seat according to claim 1, The vehicle seat, wherein the reinforcing member is disposed on the surface of the seat pad.

3. 2. The vehicle seat according to claim 1, The vehicle seat, wherein the reinforcing member is disposed on the back surface of the seat pad or inside the seat pad.

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