Vehicle seat device and intake and exhaust valve device

This application is based on and claims priority under 35 U.S.C. § 119 to Japanese Patent Application 2016-124973, filed on Jun. 23, 2016, the entire contents of which are incorporated herein by reference.

This disclosure relates to a vehicle seat device and an intake and exhaust valve device.

In the related art, there has been a vehicle seat device in which air bags (bladders) configured to be provided inside a seat are expanded and contracted, so that the support shape of the seat can be changed. For example, a seat device disclosed in JP 2010-233898 A (Reference 1) includes a plurality of air bags configured to be provided inside a seat, a flow path having a shared section and communicating with each of the air bags, and an air pump that pumps air to each of the air bags via the flow path. The seat device further includes a plurality of intake valves each of which is provided at a flow path position at an upstream of one of the air bags when air is pumped into each of the air bags, and an exhaust valve (an integrated exhaust valve) provided at a flow path position communicating with the shared section. In addition, each of the air bags is expanded and contracted by controlling operations of the air pump, each of the intake valves, and the exhaust valve.

That is, when each air bag is filled with air, the air pump is driven in a state where the intake valve provided at the upstream of the target air bag is opened, and the exhaust valve is closed. When air is discharged from the air bag, the intake valve corresponding to the target air bag is opened and the exhaust valve provided at the flow path position communicating with the shared section is opened in a state where the air pump is stopped. As described above, when the internal air of each air bag is discharged to the outside, one exhaust valve is used in common, thereby achieving the simplification of the structure.

However, in many cases, the sizes (internal capacities) of air bags provided inside a vehicle seat are set depending on seat positions where the air bags are arranged. Thus, in the above described configuration of the conventional technology, in which one exhaust valve is shared, there is a problem in that when a seat support shape is changed by discharging internal air filled in each of air bags, a difference is likely to occur in the operation speed. Then, there is a possibility that an occupant seated on the seat may feel uncomfortable, and in this respect, there is still room for improvement.

Thus, a need exists for a vehicle seat device and an intake and exhaust valve device which are not susceptible to the drawback mentioned above.

It is preferable that a vehicle seat device according to an aspect of the disclosure includes: a plurality of air bags provided inside a seat; a flow path having a shared section and communicating with each of the air bags; a plurality of intake valves each of which is arranged at a flow path position at an upstream of each of the air bags when air is pumped into each of the air bags; a plurality of exhaust valves arranged at flow path positions communicating with the shared section; and a control device configured to control operations of the intake valves and the exhaust valves, in which the control device adjusts a discharge speed of internal air by selectively opening the exhaust valves when the internal air of each of the air bags is discharged.

The foregoing and additional features and characteristics of this disclosure will become more apparent from the following detailed description considered with the reference to the accompanying drawings, wherein:

FIG. 1 is a perspective view illustrating a vehicle seat inside which air bags are provided;

FIG. 2 is a schematic configuration diagram illustrating a seat device;

FIG. 3 is a schematic configuration diagram illustrating the seat device;

FIG. 4 is an explanatory view illustrating a relationship between an internal capacity of an air bag and a number of exhaust valves to be opened;

FIG. 5 is a flow chart of an away control;

FIG. 6 is a time chart illustrating an aspect of the away control;

FIG. 7 is a graph illustrating a relationship between an air flow rate of a flow path and a pressure loss occurring in the flow path (when air is pumped);

FIG. 8 is a graph illustrating a relationship between an air flow rate of a flow path and an inlet pressure of the flow path (when air is pumped);

FIG. 9 is a graph illustrating a relationship between an air flow rate of a flow path and a pressure detection value by a pressure sensor (when air is pumped);

FIG. 10 is a graph illustrating a relationship between an air flow rate of a flow path and a pressure loss from the pressure sensor to the air bag (when air is pumped);

FIG. 11 is a graph illustrating a change in a pressure loss according the passage of time from initiation of driving of an air pump (when air is pumped);

FIG. 12 is an explanatory view illustrating a relationship between a value of a correction coefficient corresponding to a change in an air flow rate and an elapsed time;

FIG. 13 is a graph illustrating a relationship between an air flow rate of a flow path and a pressure detection value by the pressure sensor (when internal air is discharged); and

FIG. 14 is a graph illustrating a relationship between an air flow rate of a flow path and a pressure loss from the air bag to the pressure sensor (when internal air is discharged).

Hereinafter, descriptions will be made on a seat device having a pneumatic seat support function and an intake and exhaust valve device constituting the seat device according to a first embodiment with reference to drawings.

As illustrated in FIG. 1 , a seat 1 for a vehicle includes a seat cushion 2 , and a seat back 3 provided at the rear end portion of the seat cushion 2 . A headrest 4 is provided at the upper end of the seat back 3 .

In the seat 1 according to the embodiment, the seat back 3 has a shape in which both side portions 3 a and 3 b bulge forward. Also, the seat cushion 2 has a shape in which both side portions 2 a and 2 b bulge upward. Accordingly, in the seat 1 according to the embodiment, it is possible to secure a good seating posture of the occupant and to maintain the seating posture.

In the seat 1 , a plurality of air bags 10 ( 11 to 16 ) are provided inside the seat cushion 2 and the seat back 3 . Specifically, in the seat 1 according to the embodiment, separate air bags 11 ( 11 a and 11 b ), 12 ( 12 a to 12 c ), 13 , and 14 ( 14 a and 14 b ) are provided at positions corresponding to a shoulder portion (shoulder), a waist portion (lumbar), and a lower end portion (back pelvis) of a backrest face 3 s , and the both side portions 3 a and 3 b , respectively, inside the seat back 3 . In the seat cushion 2 as well, separate air bags 15 and 16 ( 16 a and 16 b ) are provided inside the rear end portion (cushion pelvis) on a seating surface 2 s and inside the both side portions 2 a and 2 b , respectively. Accordingly, in the seat 1 according to the embodiment, a seat device 20 is formed in which a seat support shape may be changed based on expansion and contraction of each of the air bags 10 .

More specifically, as illustrated in FIG. 2 , the seat device 20 according to the embodiment includes an air pump 21 that pumps air to each of the air bags 10 , and an intake/exhaust valve device 22 interposed between each of the air bags 10 and the air pump 21 . As the air pump 21 according to the embodiment, an electric pump using a motor 23 as a driving source is used. The intake/exhaust valve device 22 is connected to each of the air bags 10 and the air pump 21 via a flexible resin tube 24 . That is, in the seat device 20 according to the embodiment, a flow path L is formed by the tube 24 and the internal passage of the intake/exhaust valve device 22 to communicate with each of the air bags 10 and the air pump 21 . Accordingly, the intake/exhaust valve device 22 according to the embodiment includes a plurality of intake valves 25 and a plurality of exhaust valves 26 arranged in the middle of the flow path L.

In the seat device 20 according to the embodiment, operations of the intake valves 25 , the exhaust valves 26 , and the air pump 21 are controlled by a control device 30 . Specifically, the control device 30 according to the embodiment detects an internal pressure P of each of the air bags 10 , based on a signal output from a pressure sensor 31 . An operation input signal Sc for an operation switch 32 provided in the seat 1 , an ignition signal Sig, a door lock signal Sdl, or the like is input to the control device 30 . Based on the control signals, the control device 30 according to the embodiment controls the operations of the intake valves 25 , the exhaust valves 26 , and the air pump 21 so as to expand and contract each of the air bags 10 .

More specifically, as illustrated in FIG. 3 , in the seat device 20 according to the embodiment, the flow path L includes a main line L 0 extending from the air pump 21 , and a plurality of branch lines L 1 to L 14 branching off from the main line L 0 . Specifically, the seat device 20 according to the embodiment includes a check valve 33 that prevents a backward flow of air pumped from the air pump 21 , in the main line L 0 of the flow path L. The flow path L in the embodiment has a configuration in which when the air pump 21 side is defined as the upstream, each of the branch lines L 1 to L 14 independently branches off from the main line L 0 at the downstream side in relation to the check valve 33 . Each of the air bags 10 for seat support is connected to each of the branch lines L 1 to L 14 , one by one.

In the seat device 20 according to the embodiment, the air bag 13 for back pelvis support is connected to the branch line L 1 , and the air bags 12 a to 12 c for lumbar support are connected to the branch lines L 2 to L 4 , respectively. The air bags 11 a and 11 b for shoulder support are connected to the branch lines L 7 and L 8 , respectively, and the air bags 14 a and 14 b for backside support are connected to the branch lines L 9 and L 10 , respectively. The air bags 16 a and 16 b for cushion side support are connected to the branch lines L 12 and L 13 , respectively, and the air bag 15 for cushion pelvis is connected to the branch line L 14 .

In the seat device 20 according to the embodiment, the intake/exhaust valve device 22 has a configuration in which the intake valves 25 ( 25 a to 25 k ) are arranged in the branch lines L 1 to L 4 , L 7 to L 10 , and L 12 to L 14 of the flow path L, respectively, to which the air bags 10 are connected. Specifically, each of the intake valves 25 ( 25 a to 25 k ) is arranged at an upstream position of each of the air bags 10 , when air is pumped into each of the air bags 10 . The intake/exhaust valve device 22 according to the embodiment has a configuration in which the exhaust valves 26 ( 26 a to 26 c ) are arranged in the branch lines L 5 , L 6 , and L 11 of the flow path L, respectively, to which the air bags 10 are not connected.

In the intake/exhaust valve device 22 according to the embodiment, the intake valves 25 ( 25 a to 25 d ) arranged in the branch lines L 1 to L 4 are partitioned into a first intake valve group G 1 , and the intake valves 25 ( 25 e to 25 h ) arranged in the branch lines L 7 to L 10 are partitioned into a second intake valve group G 2 . The intake valves 25 ( 25 i to 25 k ) arranged in the branch lines L 12 to L 14 are partitioned into a third intake valve group G 3 . The exhaust valves 26 ( 26 a to 26 c ) are arranged in the branch lines L 5 , L 6 , and L 11 , respectively, so that the exhaust valves 26 ( 26 a to 26 c ) are distributed in the first to third intake valve groups G 1 to G 3 , respectively.

That is, when each air bag 10 is expanded, the control device 30 in the embodiment drives the air pump 21 in a state where the intake valve 25 (e.g., the intake valve 25 a ) located at the upstream of the target air bag 10 (e.g., the air bag 13 ) is opened, and all of the exhaust valves 26 ( 26 a to 26 c ) provided in the branch lines L 5 , L 6 , and L 11 , respectively, are closed.

When each air bag 10 is contracted, the control device 30 opens the intake valve 25 (e.g., the intake valve 25 a ) corresponding to the target air bag 10 (e.g., the air bag 13 ), and selectively opens the exhaust valves 26 ( 26 a to 26 c ) provided in the branch lines L 5 , L 6 , and L 11 , respectively, in a state where the air pump 21 is stopped. That is, while the intake valve 25 provided in the upstream and the exhaust valve 26 are opened, the internal air of each air bag 10 is discharged to the outside from the opened exhaust valve 26 via the main line L 0 which is a shared section LC of the flow path L. Accordingly, the control device 30 according to the embodiment is configured to adjust the discharge speed when the internal air of each air bag 10 is discharged by selecting the exhaust valve 26 to be opened.

Specifically, as illustrated in FIG. 4 , in the seat device 20 according to the embodiment, the air bag 15 for cushion pelvis, the air bags 16 ( 16 a and 16 b ) for cushion side support, and the air bag 13 for back pelvis support are classified into a first group A 1 having a relatively small internal capacity (left-right total value). The air bags 11 ( 11 a and 11 b ) for shoulder support and the air bags 14 ( 14 a and 14 b ) for backside support are classified into a second group A 2 having a relatively large internal capacity (left-right total value). The exhaust valves 26 ( 26 a to 26 c ), which are arranged in the branch lines L 5 , L 6 , and L 11 , respectively, which communicate with the shared section LC of the flow path L as described above, have the same exhaust flow rate per unit time.

In view of this point, when the internal air of each of the air bags 10 ( 13 , 15 , and 16 ) belonging to the first group A 1 having a relatively small internal capacity is discharged, the control device 30 according to the embodiment opens only the first exhaust valve 26 a . When the internal air of each of the air bags 10 ( 11 and 14 ) belonging to the second group A 2 having a relatively large internal capacity is discharged, the first and second exhaust valves 26 a and 26 b are opened. Accordingly, the seat device 20 according to the embodiment has a configuration in which a difference hardly occurs in an operation speed based on the internal capacity of each air bag 10 when a seat support shape is changed.

As illustrated in FIG. 3 , in the seat device 20 according to the embodiment, in the branch lines L 2 to L 4 , to which the air bags 12 ( 12 a to 12 c ) for lumbar support are connected, respectively, the exhaust valves 26 ( 26 d to 26 f ) dedicated to the air bags 12 are respectively provided at positions at the downstream side with respect to the intake valves 25 ( 25 b to 25 d ). That is, the seat device 20 according to the embodiment has a configuration in which the air bags 12 ( 12 a to 12 c ) for lumbar support are separately expanded and contracted using the exhaust valves 26 ( 26 d to 26 f ), respectively. For example, the air bags 12 arranged in the vertical direction of the seat back 3 may be sequentially expanded and contracted so that the lumbar support shape formed in the waist portion of the backrest face 3 s may be moved up and down.

As illustrated in the flow chart of FIG. 5 , when detecting that the occupant is getting off the vehicle based on the ignition signal Sig, the door lock signal Sdl or the like (step 101 : YES), the control device 30 executes an away contraction control of shifting the plurality of air bags 10 to a contracted state (step 102 ). Specifically, the control device 30 in the embodiment contracts all of the air bags 10 for seat support during the away control. Then, the control device 30 selects a full opening state in which all of the exhaust valves 26 ( 26 a to 26 c ), which are provided in the branch lines L 5 , L 6 , and L 11 , respectively, are opened in order to discharge the internal air of the air bags 10 ( 11 and 13 to 16 ) other than the air bags 12 for lumbar support which have the above described dedicated exhaust valves 26 ( 26 d to 26 f ).

Specifically, as illustrated in the time chart of FIG. 6 , first, the control device 30 opens the intake valves 25 ( 25 g , 25 h , 25 i , and 25 j ), which are provided in the branch lines L 9 , L 10 , L 12 , and L 13 , respectively, which communicate with the air bags 14 ( 14 a and 14 b ), and 16 ( 16 a and 16 b ) for side support so as to contract the air bags 14 and 16 (time T 1 ). The control device 30 opens all of the exhaust valves 26 ( 26 a to 26 c ), which are provided in the branch lines L 5 , L 6 , and L 11 , respectively, while opening the intake valves 25 ( 25 g , 25 h , 25 i , and 25 j ). After a lapse of a predetermined time, the exhaust valves 26 ( 26 a to 26 c ) are closed (time T 2 ), and then the intake valves 25 ( 25 g , 25 h , 25 i , and 25 j ) corresponding to the air bags 14 and 16 are closed (time T 3 ).

Next, the control device 30 opens the intake valves 25 ( 25 a , 25 e , 25 f , and 25 k ), which are provided in the branch lines L 1 , L 7 , L 8 , and L 14 , respectively, which communicate with the air bags 11 ( 11 a and 11 b ) for shoulder support and the air bags 13 and 15 for pelvis support so as to contract the air bags 11 , 13 , and 15 (time T 4 ). The control device 30 opens all of the exhaust valves 26 ( 26 a to 26 c ), which are provided in the branch lines L 5 , L 6 , and L 11 , respectively, while opening the intake valves 25 ( 25 a , 25 e , 25 f , and 25 k ). After a lapse of a predetermined time, the exhaust valves 26 ( 26 a to 26 c ) are closed (time T 5 ), and then the intake valves 25 ( 25 a , 25 e , 25 f , and 25 k ) corresponding to the air bags 11 , 13 , and 15 are closed (time T 6 ).

After contracting the air bags 10 ( 11 and 13 to 16 ), the control device 30 in the embodiment contracts the air bags 12 ( 12 a to 12 c ) for lumbar support. When the internal air of the air bags 12 is discharged, also in this away control, the exhaust valves 26 ( 26 d to 26 f ), which are dedicated to the air bags 12 , respectively, are used (time T 7 to time T 9 ).

In addition, as illustrated in FIG. 3 , in the seat device 20 according to the embodiment, in the main line L 0 of the flow path L, the pressure sensor 31 is provided at a position at the downstream side of the check valve 33 which is the shared section LC. That is, when one of the intake valves 25 is opened and each of the exhaust valves 26 is closed, the air pressure of the shared section LC in which the pressure sensor 31 is provided becomes substantially equal to the internal pressure P of the air bag 10 corresponding to the opened intake valve 25 (e.g., the air bag 11 a for shoulder support which communicates with the branch line L 7 when the intake valve 25 e is opened). Accordingly, the control device 30 in the embodiment is configured to expand and contract each of the air bags 10 while monitoring the internal pressure P.

More specifically, the control device 30 in the embodiment maintains a target value (an internal pressure target value P0) of the internal pressure P of each air bag 10 in a storage area 30 a (see FIG. 2 ). In the seat device 20 according to the embodiment, the internal pressure target value P0 of each air bag 10 is updated when the occupant sets an optimum support shape using the operation switch 32 (see FIG. 2 ) (support shape adjustment operation). The control device 30 in the embodiment is configured to control the operations of the intake valves 25 and the exhaust valves 26 of the intake/exhaust valve device 22 and the air pump 21 so that the internal pressure P of each air bag 10 to be detected coincides with the internal pressure target value P0.

More specifically, the control device 30 in the embodiment duty-controls the motor 23 of the air pump 21 by executing a PWM control when expanding each air bag 10 . In the embodiment, the duty ratio (motor duty ratio) at the time of driving the air pump 21 is set for each of seat portions where each of the air bags 10 is arranged, that is, for each air bag 10 . Accordingly, the seat device 20 according to the embodiment is configured to suppress a pressure loss occurring in the flow path L by making the flow rate of air pumped from the air pump 21 constant.

(Correction Control of Pressure Detection Value)

Hereinafter, descriptions will be made on a correction control of a pressure detection value executed by the control device 30 according to the embodiment.

The control device 30 according to the embodiment executes the correction control on an internal pressure P of each air bag 10 , which is detected using the pressure sensor 31 as described above, in consideration of a pressure loss ΔP occurring in the flow path L. The control device 30 executes an expansion/contraction control of each air bag 10 based on a corrected pressure value P′.

More specifically, when air is pumped from the air pump 21 so as to expand each air bag 10 , the control device 30 according to the embodiment corrects the internal pressure P of each air bag 10 detected by the pressure sensor 31 , based on the following internal pressure correction equation in which an internal pressure correction value for the pressure loss is set as “Pc.”

P′=P−Pc   (1)

That is, assuming that the pressure loss from the air pump 21 to the pressure sensor 31 in the flow path L is “first intake pressure loss ΔPi1,” a pressure detection value Ps obtained by the pressure sensor 31 becomes a value obtained by subtracting the first intake pressure loss ΔPi1 from an inlet pressure Pa in the flow path L as indicated in the following equation.

Ps=Pa−ΔPi 1  (2)

Assuming that the pressure loss from the pressure sensor 31 to each air bag 10 in the flow path L is “second intake pressure loss ΔPi2,” an actual internal pressure Px of the air bag 10 to be detected becomes a value obtained by subtracting the second intake pressure loss ΔPi2 from the pressure detection value Ps obtained by the pressure sensor 31 as indicated in the following equation. The above equation (1) is based on the relationship indicated in the equation (3).

Px=Ps−ΔPi 2  (3)

The pressure loss ΔP occurring in the flow path L may be obtained by the following equation (4) (Darcy Weisbach equation) from each of parameters including a pipe friction coefficient λ, a pipe length Lx, a pipe inner diameter D, a gas density in the pipe (air density) γ, and a pipe flow velocity V. In the following equation and subsequent equations, “^2” and “^4” indicate “second power” and “fourth power,” respectively.

ΔP =λ×( Lx/D )×(γ×( V^ 2)/2)  (4)

The equation (4) may be modified to the equation (7) from the relationship of the equation (6) by introducing a pressure loss coefficient K based on the structure of the flow path L as indicated in the following equation (5).

K=λ× ( Lx/D )  (5)

V=Q /(π×( D^ 2)/4)  (6)

ΔP =(8/(π^2))×γ×(( K/D^ 4)×( Q^ 2))  (7)

That is, as illustrated in FIG. 7 , the pressure loss ΔP occurring in the flow path L increases in proportion to the second power of the air flow rate Q in the flow path L (ΔP∝Q^2). As illustrated in FIG. 8 , the air flow rate Q in the flow path L, which is generated by driving the air pump 21 , decreases in proportion to the pressure of air pumped by the air pump 21 , that is, the inlet pressure Pa of the flow path L. Based on FIGS. 7 and 8 , and the relationship indicated in the above equation (2), a pressure flow rate characteristic (PQ characteristic) is obtained at the location of the flow path L where the pressure sensor 31 is provided as illustrated in FIG. 9 .

Based on the pressure flow rate characteristic, the air flow rate Q (the flow rate value Q1 in FIG. 9 ) in the flow path L may be obtained from the pressure detection value Ps (the pressure value P1 in FIG. 9 ) obtained by the pressure sensor 31 . As illustrated in FIG. 10 , based on the value of the air flow rate Q (the flow rate value Q1), the value of the second intake pressure loss ΔPi2 (the pressure value P2) from the pressure sensor 31 to each air bag 10 in the flow path L may be obtained.

That is, the pressure loss ΔP occurring in the flow path L during pumping of air by the air pump 21 is expressed by a relational expression of the pressure detection value Ps obtained by the pressure sensor 31 and a square root thereof (ΔP∝Ps, √Ps). Using the following equation (8) employing this relational expression, the control device 30 according to the embodiment calculates an internal pressure correction value Pc corresponding to the second intake pressure loss ΔPi2 from the pressure sensor 31 to each air bag 10 .

Pc=α 1×(( Ps−α 2)^2)×α3  (8)

In the equation (8), “α1” “α2,” and “α3” are correction coefficients.

That is, the correction coefficient α2 is a value corresponding to a maximum pressure Pm generated by the air pump 21 (see FIG. 9 ). The correction coefficient α3 is a value corresponding to a change of the air flow rate Q generated by driving the air pump 21 .

More specifically, as illustrated in FIG. 11 , the pressure loss ΔP occurring in the flow path L rapidly increases immediately after the driving of the air pump 21 is initiated, as the air flow rate Q steeply increases. Then, after the steep change of the air flow rate Q converges, the pressure loss ΔP gradually decreases as the air flow rate Q decreases.

Based on this point, as illustrated in FIG. 12 , the value of the correction coefficient α3 in the above equation (8) is classified according to the elapsed time t from the occurrence of a pressure change accompanying the driving of the air pump 21 . Specifically, when the elapsed time t is “0,” the control device 30 according to the embodiment sets the value of the correction coefficient α3 to “0.” Until the elapsed time reaches a preset initial time T 1 , the value of the correction coefficient α3 is set to “t/t 1 .” Then, after the initial time T 1 is exceeded, the value of the correction coefficient α3 is set to “1.”

That is, when a pressure change accompanying the driving of the air pump 21 does not occur (t=0), the pressure loss ΔP of the flow path L also does not occur. Accordingly, in this case, the internal pressure correction value Pc is set to be “0.” Then, immediately after the driving of the air pump 21 is initiated, the value of the correction coefficient α3 gradually changes until the steep change of the air flow rate Q converges (0<t≤t 1 ).

After a predetermined time has elapsed from the start of driving of the air pump 21 , or after any one intake valve 25 is opened, when the pressure detection value Ps obtained by the pressure sensor 31 is stabilized and then increases by a predetermined value or more, the control device 30 according to the embodiment determines that the pressure change accompanying the driving of the air pump 21 has occurred.

In the case of detecting the internal pressure P of the air bag 10 when the internal air is discharged so as to contract each air bag 10 , the control device 30 according to the embodiment corrects the internal pressure P of each air bag 10 detected by the pressure sensor 31 , based on the following internal pressure correction equation in which an internal pressure correction value for a pressure loss is set as “Pd.”

P′=P+Pd   (9)

That is, assuming that the pressure loss from each air bag 10 to the pressure sensor 31 in the flow path L is “first exhaust pressure loss ΔPe1” when the internal air is discharged using the exhaust valve 26 , an actual internal pressure Px of the air bag 10 to be detected becomes a value obtained by adding the first exhaust pressure loss ΔPe1 to the pressure detection value Ps obtained by the pressure sensor 31 as indicated in the following equation (10). The above equation (9) is based on the relationship represented in the equation (10).

Px=Ps+ΔPe 1  (10)

Here, assuming that the pressure loss from the pressure sensor 31 to the exhaust valve 26 in the flow path L is “second exhaust pressure loss ΔPe2,” an outlet pressure Pb of the flow path L becomes a value obtained by subtracting the second exhaust pressure loss ΔPe2 from the pressure detection value Ps obtained by the pressure sensor 31 .

Pb=Ps−ΔPe 2  (11)

Accordingly, as illustrated in FIG. 13 , from the above equation (7), the pressure detection value Ps obtained by the pressure sensor 31 increases in proportion to the second power of the flow rate Q of air discharged from the flow path L to the outside. Based on the pressure flow rate characteristic (PQ characteristic), the air flow rate Q (the flow rate value Q2 in FIG. 13 ) in the flow path L may be obtained from the pressure detection value Ps (the pressure value P3 in FIG. 13 ) obtained by the pressure sensor 31 . As illustrated in FIG. 14 , based on the value of the air flow rate Q (the flow rate value Q2), the value of the first exhaust pressure loss ΔPe1 from each air bag 10 to the pressure sensor 31 in the flow path L (the pressure value P4 in FIG. 14 ) may be obtained.

That is, the pressure loss ΔP occurring in the flow path L when the internal air is discharged using the exhaust valve 26 is expressed by a relational expression of the pressure detection value Ps obtained by the pressure sensor 31 (ΔP∝Ps). Using the following equation (12) employing this relational expression, the control device 30 according to the embodiment calculates an internal pressure correction value Pd corresponding to the first exhaust pressure loss ΔPe1 from each air bag 10 to the pressure sensor 31 .

Pd=β 1× Ps×β 2  (12)

In the equation (12), “β1” and “β2” are correction coefficients. The correction coefficient β2 in the equation is a value corresponding to a change of the air flow rate Q accompanying the opening of the exhaust valve 26 .

That is, the value of the correction coefficient β2 in the equation (12) is also classified according to the elapsed time t from the occurrence of a pressure change accompanying the opening of the exhaust valve 26 (see FIG. 12 ). In this case, after a predetermined time has elapsed from the opening of the exhaust valve 26 , or after any one intake valve 25 is opened, when the pressure detection value Ps obtained by the pressure sensor 31 is stabilized and then decreases by a predetermined value or more, the control device 30 according to the embodiment determines that the pressure change accompanying the opening of the exhaust valve 26 has occurred.

As described above, according to the embodiment, the following effects may be achieved.

(1) The seat device 20 includes the plurality of air bags 10 provided inside the seat 1 , and the flow path L having a shared section LC and communicating with the air bags 10 . The seat device 20 includes the plurality of intake valves 25 each of which is arranged at a flow path position at the upstream side of each of the air bags 10 when air is pumped into each of the air bags 10 , the plurality of exhaust valves 26 ( 26 a to 26 c ) arranged at flow path positions communicating with the shared section LC of the flow path L, and the control device 30 that controls the operations of the intake valves 25 and the exhaust valves 26 . The control device 30 adjusts the discharge speed of internal air when the internal air of each air bag 10 is discharged by selectively opening the exhaust valves 26 .

According to the above configuration, it is possible to adjust the discharge speed of the internal air filled in each air bag 10 with a simple configuration without causing complication and enlargement of the exhaust valves 26 . As a result, for example, a difference between seat portions hardly occurs in an operation speed when a seat support shape is changed. Accordingly, it is possible to improve the feeling of use of the occupant.

(2) When the internal air of each of the air bags 10 ( 13 , 15 , and 16 ) belonging to the first group A 1 having a relatively small internal capacity is discharged, the control device 30 opens only the first exhaust valve 26 a . When the internal air of each of the air bags 10 ( 11 and 14 ) belonging to the second group A 2 having a relatively large internal capacity is discharged, the first and second exhaust valves 26 a and 26 b are opened.

That is, as described above, the number of exhaust valves 26 to be opened increases according to the internal capacity of each air bag 10 from which the internal air is discharged. Thus, a difference hardly occurs in an operation speed based on the internal capacity of each air bag 10 when a seat support shape is changed. Accordingly, it is possible to improve the feeling of use of the occupant.

(3) When detecting that the occupant is getting off the vehicle, the control device 30 executes an away control of shifting the plurality of air bags 10 to a contracted state. Then, in the away control, when the internal air of the air bags 10 ( 11 and 13 to 16 ) other than the air bags 12 for lumbar support is discharged, the control device 30 selects a full opening state in which all of the exhaust valves 26 ( 26 a to 26 c ) provided in the branch lines L 5 , L 6 , and L 11 , respectively, that is, at flow path positions communicating with the shared section LC, are opened.

According to the above configuration, the away control may be quickly completed. Accordingly, it is possible to improve the feeling of use of the occupant.

(4) In the intake/exhaust valve device 22 , the intake valves 25 are partitioned into a plurality of intake valve groups G (G 1 to G 3 ). The exhaust valves 26 ( 26 a to 26 c ) arranged at flow path positions communicating with the shared section of the flow path L are provided to be distributed in the intake valve groups G, respectively.

According to the above configuration, the intake and exhaust function of each intake valve group G may be completed. As a result, by selecting which of intake valve groups G to use, or selecting which of combinations of the intake valve groups G to use, the configuration may be employed in various seats which are different in seat portions where the air bags 10 are arranged. Accordingly, it is possible to secure excellent versatility.

For example, for seats provided with the air bags 12 a to 12 c , and 13 for lumbar support and back pelvis support, the intake valves 25 a to 25 d and the exhaust valves 26 a , and 26 d to 26 f partitioned into the first intake valve group G 1 may be used. In addition to this, for seats provided with the air bags 11 a , 11 b , 14 a , and 14 b for shoulder support and backside support, the intake valves 25 e to 25 h and the exhaust valve 26 b partitioned into the second intake valve group G 2 may be additionally used. For seats provided with the air bags 15 , 16 a , and 16 b for cushion pelvis and cushion side support, the intake valves 25 i to 25 k and the exhaust valve 26 c partitioned into the third intake valve group G 3 may be additionally used.

The embodiment may be modified as follows.

In the above embodiment, the exhaust valves 26 ( 26 a to 26 c ) arranged at the flow path positions communicating with the shared section of the flow path L have the same exhaust flow rate per unit time. However, the disclosure is not limited thereto. A plurality of exhaust valves 26 having different exhaust flow rates may be provided at the flow path positions communicating with the shared section of the flow path L. For example, when the internal air is discharged, the exhaust valve 26 having a larger discharge flow rate may be selected according to the size of the internal capacity of the air bag 10 . When the plurality of exhaust valves 26 are opened simultaneously, the discharge speed of the internal air may be more accurately adjusted by the combination.

In the above embodiment, in the intake/exhaust valve device 22 , the intake valves 25 are partitioned into the plurality of intake valve groups G (G 1 to G 3 ), and each of the exhaust valves 26 ( 26 a to 26 c ) arranged at the flow path positions communicating with the shared section LC is provided for each of the intake valve groups G. However, the disclosure is not limited thereto. The total number of the intake valves 25 and the number of the intake valve groups G may be arbitrarily changed. The number of the intake valves 25 and the number of the exhaust valves 26 belonging to each intake valve group G may also be arbitrarily changed. Meanwhile, in consideration of versatility, at least one exhaust valve 26 may be provided for each intake valve group G. It is possible to arbitrarily set which one of the intake valve groups G to use, or which air bag 10 arranged in which seat portion is to be connected.

In the above embodiment, the number of the exhaust valves 26 to be opened increases according to the internal capacity of the air bag 10 from which the internal air is discharged. However, the disclosure is not limited thereto. The exhaust valve 26 to be opened may be selected according to the seat portion in which the air bag 10 from which the internal air is to be discharged is arranged. Accordingly, it is possible to optimize the operation speed for each seat portion in which the air bag is arranged.

The number of the exhaust valves 26 to be opened may increase according to the discharge amount of the internal air. Accordingly, it is possible to more quickly complete the discharge of the internal air.

In the above embodiment, in the away control in which all of the air bags 10 for seat support are contracted, first, the air bags 14 ( 14 a and 14 b ) and 16 ( 16 a and 16 b ) for side support are contracted, and then the air bags 11 ( 11 a and 11 b ) for shoulder support and the air bags 13 and 15 for pelvis support are contracted. Then, in these two processes, a full opening state is selected in which all of the exhaust valves 26 ( 26 a to 26 c ) provided at the flow path positions communicating with the shared section LC are opened. However, the disclosure is not limited thereto. In the away control, it is possible to arbitrarily set any of processes for which the full opening state is to be selected. That is, the away control only has to include selection of the full opening state in which all of the exhaust valves 26 communicating with the shared section are opened at any timing. The away control does not necessarily have to contract all of the air bags 10 . Regarding the manner of the away control, the air bags 10 may be contracted at once, the air bags 10 may be successively and sequentially contracted, or a combination thereof may be employed.

In the above embodiment, the exhaust valves 26 ( 26 a to 26 c ) are arranged in the branch lines L 5 , L 6 , and L 11 of the flow path L, respectively, to which the air bags 10 are not connected, and the exhaust valves 26 are arranged at the flow path positions communicating with the shared section LC of the flow path L. However, the disclosure is not limited thereto. As long as the flow path position communicates with the shared section LC, the flow path position at which each exhaust valve 26 is arranged, including the main line L 0 which becomes the shared section LC, may be arbitrarily changed.

It is preferable that a vehicle seat device according to an aspect of the disclosure includes: a plurality of air bags configured to be provided inside a seat; a flow path having a shared section and communicating with each of the air bags; a plurality of intake valves each of which is arranged at a flow path position at an upstream of each of the air bags when air is pumped into each of the air bags; a plurality of exhaust valves arranged at flow path positions communicating with the shared section; and a control device configured to control operations of the intake valves and the exhaust valves, in which the control device adjusts a discharge speed of internal air by selectively opening the exhaust valves when the internal air of each of the air bags is discharged.

According to this configuration, it is possible to adjust the discharge speed of the internal air filled in each air bag with a simple configuration without causing complication and enlargement of the exhaust valves. As a result, for example, a difference between seat portions hardly occurs in an operation speed when a seat support shape is changed. Accordingly, it is possible to improve the feeling of use of the occupant.

In the vehicle seat device, it is preferable that the control device increases a number of the exhaust valves to be opened according to an internal capacity of each of the air bags from which the internal air is discharged.

According to this configuration, a difference hardly occurs in an operation speed based on the internal capacity of each air bag when the internal air of the air bag is discharged. Accordingly, it is possible to improve the feeling of use of the occupant.

In the vehicle seat device, it is preferable that the control device increases a number of the exhaust valves to be opened according to a discharge amount of the internal air. According to this configuration, it is possible to more quickly complete the discharge of the internal air.

In the vehicle seat device, it is preferable that the plurality of exhaust valves have different exhaust flow rates.

According to this configuration, by selecting the exhaust valve to be opened, the discharge speed of the internal air may be precisely adjusted. When the plurality of exhaust valves are opened simultaneously, the discharge speed of the internal air may be more accurately adjusted by the combination.

In the vehicle seat device, it is preferable that the control device selects the exhaust valves to be opened according to a seat portion in which each of the air bags from which the internal air is discharged is arranged.

According to this configuration, it is possible to optimize the operation speed for each seat portion in which the air bag is arranged.

In the vehicle seat device, it is preferable that the control device executes an away control of shifting the plurality of air bags to a contracted state, and the away control includes selecting a full opening state in which all of the exhaust valves communicating with the shared section are opened.

According to this configuration, the away control may be quickly completed. Accordingly, it is possible to improve the feeling of use of the occupant.

It is preferable that an intake and exhaust valve device according to another aspect of the disclosure includes: a plurality of intake valves each of which is arranged at a flow path position at an upstream of each of air bags when air is pumped into each of the air bags in a flow path having a shared section and communicating with each of the air bags; and a plurality of exhaust valves arranged at flow path positions communicating with the shared section.

According to this configuration, it is possible to adjust the discharge speed when the internal air of each air bag is discharged by selectively opening the exhaust valves. Accordingly, it is possible to reduce a size of a device by avoiding complication and enlargement of the exhaust valves.

In the intake and exhaust valve device, it is preferable that the intake valves are partitioned into a plurality of intake valve groups, and at least one of the exhaust valves is provided in each of the intake valve groups.

According to this configuration, the intake and exhaust function of each intake valve group may be completed. As a result, by selecting which of intake valve groups to use, or selecting which of combinations of the intake valve groups to use, the configuration may be employed in various seats which are different in seat portions where the air bags are arranged. Accordingly, it is possible to secure excellent versatility.

According to the aspects of this disclosure, the discharge speed of the internal air filled in the air bag may be adjusted with a simple configuration.

The principles, preferred embodiment and mode of operation of the present invention have been described in the foregoing specification. However, the invention which is intended to be protected is not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. Variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present invention. Accordingly, it is expressly intended that all such variations, changes and equivalents which fall within the spirit and scope of the present invention as defined in the claims, be embraced thereby.