JP7501175B2 - Rotary Valve - Google Patents

Description

The present invention relates to a rotary valve.

Patent document 1 describes a massage system that includes an air bag provided in a vehicle seat, a valve unit that switches the air supply state to the air bag, and a pump that sends air to the valve unit.

The valve unit includes a case in which an inlet for receiving air from an external space, an exhaust port for feeding air into an air bag, and an outlet port for discharging air returned from the air bag to the external space, a valve body having an exhaust port valve for opening and closing the exhaust port and an outlet valve for opening and closing the outlet, and a switching means for operating the valve body so that the exhaust port valve and the outlet valve are opened and closed.

The case has a diaphragm that is displaced by fluctuations in the internal pressure of the case accompanying the intake and exhaust of air. The switching means alternates between a state in which the exhaust port valve is opened and the outlet valve is closed, and a state in which the exhaust port valve is opened and the outlet valve is opened, depending on the displacement of the diaphragm. For example, when the diaphragm is displaced to a predetermined position in conjunction with an increase in the internal pressure of the case, the switching means switches from a state in which the exhaust port valve is opened and the outlet valve is closed to a state in which the exhaust port valve is opened and the outlet valve is opened.

JP 2017-72220 A

In the above valve unit, if the pump is stopped while the switching means is opening the exhaust port valve and closing the outlet valve, the air bag may remain in an inflated state without contracting. In this case, the user sitting in the vehicle seat may feel uncomfortable, or the air bag may be more susceptible to deterioration over time if it remains in an inflated state for a long period of time.

The object of the present invention is to provide a rotary valve that allows the air bag to be deflated regardless of when the air supply is stopped.

The means for solving the above problems and their effects will be described below.
A rotary valve that solves the above problem is a rotary valve that inflates and deflates an air bag by switching the mode of air supply to the air bag, and includes a case having a first air chamber to which air is supplied from an external space, a second air chamber connected to the first air chamber via a communication passage, a first exhaust port and a second exhaust port through which air discharged from the second air chamber passes, and a connection port through which air moving between the second air chamber and the air bag passes, and a case that partitions the first air chamber and the second air chamber and has a closed position and a forward position that close the second exhaust port depending on the pressure difference between the first air chamber and the second air chamber. The device comprises a piston that displaces between an open position that opens the second exhaust port, and a switching unit that is housed in the case and rotates when the pressure in the second air chamber increases and decreases, thereby switching the connection state between the second air chamber and the external space via the first exhaust port, wherein the direction in which the piston displaces from the open position to the closed position is a direction that increases the volume of the first air chamber and a direction that decreases the volume of the second air chamber, and the communicating passage limits the flow rate of air supplied from the first air chamber to the second air chamber when air is supplied from the external space to the first air chamber.

In the rotary valve of the above configuration, when the supply of air to the first air chamber is started, the flow rate of air supplied from the first air chamber to the second air chamber is limited by the communication passage to be less than the flow rate of air supplied from the external space to the first air chamber. As a result, a pressure difference occurs between the first air chamber and the second air chamber, and the piston is displaced from the open position toward the closed position. When the piston is in the closed position, the piston closes the second exhaust port, and the air supplied from the first air chamber to the second air chamber is no longer discharged to the external space. Therefore, the air supplied from the first air chamber to the second air chamber is supplied to the air bag, and the air bag expands. In addition, the pressure of the second air chamber increases with the expansion of the air bag, and the switching unit rotates. Then, the second air chamber is connected to the external space via the first exhaust port. Therefore, the air supplied to the air bag is discharged through the second air chamber, and the air bag contracts. In addition, the pressure of the second air chamber decreases with the contraction of the air bag, and the switching unit rotates. This disconnects the second air chamber from the outside space through the first exhaust port. In this way, the rotary valve inflates and deflates the air bag.

Here, assume that as the pressure in the second air chamber increases, the supply of air from the external space to the first air chamber is stopped before the second air chamber is connected to the external space through the first exhaust port. In this case, the rotary valve of the above configuration can move air between the first air chamber and the second air chamber through the communication passage, eliminating the pressure difference between the first air chamber and the second air chamber. Therefore, the piston can be displaced from a closed position that closes the second exhaust port to an open position that opens the second exhaust port. Then, the second air chamber is connected to the external space through the second exhaust port, and air is discharged from the air bag. In other words, the rotary valve can deflate the air bag. In this way, the rotary valve can deflate the air bag regardless of the timing at which the supply of air is stopped.

In the above configuration, the communication passage is preferably formed in the piston.
The rotary valve having the above configuration can simplify the structure of the device compared to a case in which the communication passage is formed in the case.

In the above configuration, it is preferable to further include a biasing member that biases the piston in a direction in which the volume of the first air chamber decreases.
In the rotary valve having the above configuration, the piston is easily displaced from the closed position to the open position when the air supply is stopped, and therefore the rotary valve can be made more reliable in contracting the air bag when the air supply is stopped.

In the above configuration, the air bag has a first air bag and a second air bag, and the connection port includes a first connection port through which air moving between the second air chamber and the first air bag passes, and a second connection port through which air moving between the second air chamber and the second air bag passes, and when the case is viewed from the axial direction of the switching unit, the first connection port and the second connection port are formed at positions sandwiching the rotation axis of the switching unit, and it is preferable that the switching unit sequentially switches between a first air supply state in which air is supplied to the first air bag through the first connection port, a first exhaust state in which air is exhausted from the first air bag through the first connection port, a second air supply state in which air is supplied to the second air bag through the second connection port, and a second exhaust state in which air is exhausted from the second air bag through the second connection port during one rotation.

The rotary valve of the above configuration can use the two connection ports, the first connection port and the second connection port, to inflate and deflate the first air bag and the second air bag in sequence during one rotation of the switching part.

In the above configuration, the connection port includes a first connection port through which air moving between the second air chamber and the air bag passes, and a second connection port through which air moving between the second air chamber and the air bag passes, and when the case is viewed from the axial direction of the switching unit, the first connection port and the second connection port are formed at positions sandwiching the rotation axis of the switching unit, and it is preferable that the switching unit switches, during one rotation, in sequence between a first air supply state in which air is supplied to the air bag via the first connection port, a first exhaust state in which air is exhausted from the air bag via the first connection port, a second air supply state in which air is supplied to the air bag via the second connection port, and a second exhaust state in which air is exhausted from the air bag via the second connection port.

The rotary valve of the above configuration can inflate and deflate the air bag twice during one rotation of the switching part by using two connection ports, the first connection port and the second connection port.

The rotary valve allows the air bag to deflate regardless of when the air supply is stopped.

1 is a schematic diagram showing a schematic configuration of a vehicle seat; FIG. 1 is a perspective view of a rotary valve according to a first embodiment. FIG. FIG. FIG. 4 is a cross-sectional view perpendicular to the radial direction of a second case of the rotary valve. FIG. 4 is a cross-sectional view perpendicular to the radial direction of a third case of the rotary valve. FIG. 4 is a cross-sectional view perpendicular to the radial direction of a fourth case of the rotary valve. FIG. 4 is a plan view of a fourth case of the rotary valve. FIG. 4 is a cross-sectional view perpendicular to the axial direction of a fifth case of the rotary valve. FIG. 4 is a plan view of a switching portion of the rotary valve. FIG. 4 is a cross-sectional view perpendicular to the axial direction of the switching portion of the rotary valve. FIG. 4 is a cross-sectional view perpendicular to the radial direction of the switching portion of the rotary valve. FIG. 2 is a cross-sectional view perpendicular to the radial direction of the rotary valve. FIG. FIG. 4 is a cross-sectional view of the rotary valve in an initial state taken along the line S1-S3-S4. FIG. 4 is a schematic diagram showing the position of a rotor of the rotary valve in an initial state. FIG. 4 is a cross-sectional view showing the position of a switching portion of the rotary valve in an initial state. 13 is a cross-sectional view of the rotary valve taken along line S1-S3-S4 when air is supplied to the first air bag. FIG. 11 is a cross-sectional view of the rotary valve taken along the line S1-S2-S3-S4 when air is discharged from the first air bag. FIG. FIG. 4 is a schematic diagram showing the position of the rotor when the second piston rises in the rotary valve. FIG. 4 is a cross-sectional view of the rotary valve when a valve element of a switching portion of the rotary valve is located in an open position. 11 is a cross-sectional view of the rotary valve taken along line S1-S3-S4 when air is supplied to the second air bag. FIG. 13 is a cross-sectional view of the rotary valve taken along the line S1-S3-S5 when air is supplied to the second air bag. FIG. FIG. 4 is a schematic diagram showing the position of the rotor when the second piston descends in the rotary valve. 4 is a cross-sectional view of the rotary valve when a valve element of a switching portion of the rotary valve is displaced from an open position to a closed position. FIG. 4 is a cross-sectional view of the rotary valve when a valve element of the switching portion of the rotary valve is located in a closed position. FIG. 13 is a cross-sectional view of the rotary valve taken along the line S1-S3-S5 when the supply of air to the rotary valve is stopped while the second air bag is inflated. FIG. 13 is a cross-sectional view of the rotary valve taken along the line S1-S3-S5 when air is discharged from the second air bag. FIG. FIG. 13 is a perspective view of a switching portion of a rotary valve according to a second embodiment. FIG. 4 is a cross-sectional view perpendicular to the radial direction of the switching portion of the rotary valve. FIG. 5A to 5C are schematic diagrams showing the rotor when the second piston rises and falls in the rotary valve. FIG. 6 is a cross-sectional view of the rotary valve in the initial state taken along line S6-S6. 34 is a cross-sectional view of the rotary valve taken along line S6-S6 of FIG. 33 when the pump starts to be driven. 6 is a cross-sectional view of the rotary valve taken along line S6-S6 when air is supplied to the first air bag. FIG. 36 is a cross-sectional view of the rotary valve taken along line S6-S6 of FIG. 35 when the driving of the pump is stopped. 6 is a cross-sectional view of the rotary valve taken along line S6-S6 when the second air chamber is no longer connected to the first air bag. 7 is a cross-sectional view of the rotary valve taken along line S7-S7 when the second air chamber is no longer connected to the first air bag. 5 is a graph showing two types of pump driving modes. 5A to 5C are schematic diagrams showing the rotor when the second piston rises and falls in the rotary valve. FIG. 11 is a perspective view of a rotary valve according to a modified example. FIG. 11 is a perspective view of a fifth case of a rotary valve according to a modified example. FIG. 11 is a perspective view of a fifth case of a rotary valve according to a modified example. FIG. 11 is a plan view of a fifth case of a rotary valve according to a modified example. FIG. 33 is a cross-sectional view of a fifth case of a rotary valve according to a modified example taken along line 33-33.

First Embodiment
Hereinafter, a seat equipped with a rotary valve according to a first embodiment will be described with reference to the drawings.

As shown in FIG. 1, the seat 10 includes a seat cushion 11, a seat back 12, a headrest 13, and a massage system 20 that massages an occupant seated in the seat 10. The seat 10 of the first embodiment is a vehicle seat that is used, for example, as a driver's seat, a passenger seat, or a rear seat of a vehicle.

The massage system 20 includes a plurality of air bags 21 built into the seat cushion 11 and the seat back 12, a pump 22 that supplies air to the plurality of air bags 21, a plurality of connection flow paths 23 that are respectively connected to the plurality of air bags 21, a supply flow path 24 that is connected to the pump 22, and a rotary valve 30 to which the plurality of connection flow paths 23 and the supply flow path 24 are connected.

The multiple air bags 21 are built into the seat cushion 11 and the seat back 12. In the first embodiment, the multiple air bags 21 consist of eight air bags 21a-21h. Of the multiple air bags 21, three air bags 21a-21c are built into the seat cushion 11, and five air bags 21d-21h are built into the seat back 12. The air bags 21 expand when air is supplied and contract when air is discharged. The air bags 21 may be composed of a single bag, or may be composed of multiple bags divided in the left and right directions of the seat 10, for example.

The pump 22 may be any pump capable of pumping air. As an example, the pump 22 is a diaphragm pump. The pump 22 is driven by power supplied from a battery (not shown). It is preferable that the multiple connection flow paths 23 and the supply flow path 24 are tubes made of, for example, rubber or resin, so that the massage system 20 can be easily mounted inside the seat 10.

The rotary valve 30 will now be described in detail.
The rotary valve 30 sequentially inflates and deflates the multiple air bladders 21 by switching the air supply mode to the multiple air bladders 21. In the following description, the rotary valve 30 of the first embodiment is said to have eight channels because it sequentially inflates and deflates eight air bladders 21.

2, the rotary valve 30 is generally cylindrical. In the following description, the axial, radial, and circumferential directions of the rotary valve 30 are referred to according to the shape of the rotary valve 30. In addition, the X-axis, Y-axis, and Z-axis are illustrated as necessary in the figures following FIG. 2. Furthermore, in the following description, the upper side in FIG. 2 is the upper side of the rotary valve 30, and the lower side in FIG. 2 is the lower side of the rotary valve 30. However, the vertical direction of the rotary valve 30 does not refer to the vertical direction of the seat 10. In other words, the rotary valve 30 may be mounted so that the axial direction is the vertical direction of the seat 10, or so that the axial direction is a direction intersecting the vertical direction of the seat 10.

As shown in FIG. 2, the rotary valve 30 includes a case 40 that houses the components of the rotary valve 30. As shown in FIGS. 3 and 4, the rotary valve 30 includes a first piston 50 and a second piston 60 that move in the axial direction, a rotor 70 that moves in the axial direction and rotates in the circumferential direction, and a switching unit 80 that rotates in the circumferential direction. The rotary valve 30 also includes a first biasing member 91 and a second biasing member 92 that bias the first piston 50 and the second piston 60, respectively, and a plurality of seal rings 101 to 105 that seal the gaps between the components of the rotary valve 30.

As shown in Figures 2 to 4, case 40 has a first case 41, a second case 42, a third case 43, a fourth case 44, and a fifth case 45 that are divided in the axial direction. Case 40 is constructed by connecting first case 41, second case 42, third case 43, fourth case 44, and fifth case 45 with fastening members such as screws. In the axial direction, first case 41 constitutes the lower part of case 40, fifth case 45 constitutes the upper part of case 40, and the remaining second case 42, third case 43, and fourth case 44 constitute the middle part of case 40.

3 and 4, the first case 41 has a first bottom wall 411 having a substantially circular plate shape, a first peripheral wall 412 extending from the periphery of the first bottom wall 411 in the axial direction, and a supply joint 413 extending from the center of the first bottom wall 411 in the opposite direction to the first peripheral wall 412. The first bottom wall 411 has a plurality of pedestals 414 supporting the first piston 50 on the surface opposite to the bottom surface, in other words, on the surface facing the inside of the case 40. The plurality of pedestals 414 are arranged at equal intervals in the circumferential direction. The first peripheral wall 412 has a first retaining groove 415 at its tip in the axial direction for retaining the first seal ring 101. The supply joint 413 has a supply port 416 through which air supplied from the pump 22 passes. The supply joint 413 is connected to the pump 22 via the supply flow path 24.

3 and 4, the second case 42 has a second bottom wall 421 having a substantially circular plate shape and a second peripheral wall 422 extending in the axial direction from the periphery of the second bottom wall 421. Also, as shown in FIG. 5, the second case 42 has a second exhaust passage 423 penetrating the second bottom wall 421 and the second peripheral wall 422. The second bottom wall 421 includes a second through hole 424 penetrating the center in the axial direction. The second exhaust passage 423 opens on the bottom surface of the second bottom wall 421 and the outer peripheral surface of the second peripheral wall 422. In the following description, the opening of the second bottom wall 421 connected to the second exhaust passage 423 is referred to as the "second exhaust port 425". The second exhaust port 425 opens downward in the second bottom wall 421.

3 and 4, the third case 43 includes a third bottom wall 431 having a substantially circular plate shape and a third peripheral wall 432 extending from the periphery of the third bottom wall 431 in the axial direction. The third bottom wall 431 has a third through hole 433 that penetrates the center in the axial direction. As shown in FIG. 6, the third peripheral wall 432 has a first guide surface 434 and a first auxiliary guide surface 435 that are inclined with respect to the axial direction, and a first connection surface 436 that connects the first guide surface 434 and the first auxiliary guide surface 435. The first guide surface 434, the first auxiliary guide surface 435, and the first connection surface 436 are arranged in a circumferential direction on the inner peripheral surface of the third peripheral wall 432. The number of the first guide surfaces 434, the first auxiliary guide surfaces 435, and the first connection surfaces 436 is the same as the number of channels of the rotary valve 30.

As shown in FIG. 6, when one direction in the circumferential direction is the first circumferential direction C1 and the other direction is the second circumferential direction C2, the first guide surface 434 is inclined upward as it advances in the first circumferential direction C1, and the first auxiliary guide surface 435 is inclined downward as it advances in the first circumferential direction C1. In the first embodiment, the first guide surface 434 and the first auxiliary guide surface 435 are inclined at an angle of approximately 45° with respect to the axial direction. In other words, the angle between the first guide surface 434 and the first auxiliary guide surface 435 is approximately 90°. On the other hand, the first connecting surface 436 extends in the axial direction. The first connecting surface 436 connects the rear end of the first guide surface 434 in the first circumferential direction C1 and the front end of the first auxiliary guide surface 435 in the first circumferential direction C1. In addition, the first guide surface 434 is longer than the first auxiliary guide surface 435.

As shown in Figures 3 and 4, the fourth case 44 is generally cylindrical. The fourth case 44 has a fourth peripheral wall 441 extending in the axial direction. The fourth peripheral wall 441 includes a small diameter portion 442 having an inner diameter and an outer diameter generally equal to those of the third peripheral wall 432 of the third case 43, a large diameter portion 443 having an inner diameter and an outer diameter larger than those of the small diameter portion 442, and a plurality of restricting walls 461 extending in the axial direction inside the large diameter portion 443.

7, the small diameter portion 442 includes a second guide surface 445 and a second auxiliary guide surface 446 that are inclined with respect to the axial direction, and a second connection surface 447 that connects the second guide surface 445 and the second auxiliary guide surface 446. The second guide surface 445, the second auxiliary guide surface 446, and the second connection surface 447 are arranged side by side in the circumferential direction on the inner peripheral surface of the third peripheral wall 432. The number of each of the second guide surfaces 445, the second auxiliary guide surfaces 446, and the second connection surfaces 447 formed is the same as the number of channels of the rotary valve 30.

As shown in FIG. 7, the second guide surface 445 is inclined downward as it advances in the first circumferential direction C1, and the second auxiliary guide surface 446 is inclined upward as it advances in the first circumferential direction C1. In the first embodiment, the second guide surface 445 and the second auxiliary guide surface 446 are inclined at an angle of approximately 45° with respect to the axial direction. In other words, the angle between the second guide surface 445 and the second auxiliary guide surface 446 is approximately 90°. On the other hand, the second connecting surface 447 extends in the axial direction. The second connecting surface 447 connects the rear end of the second guide surface 445 in the first circumferential direction C1 and the front end of the second auxiliary guide surface 446 in the first circumferential direction C1. In addition, the second guide surface 445 is longer than the second auxiliary guide surface 446.

As shown in FIG. 8, the large diameter portion 443 has a circumferential groove 448 that extends in the circumferential direction at the upper end of the large diameter portion 443, and a plurality of notches 449 that extend in the radial direction at the upper end of the large diameter portion 443. The circumferential groove 448 is recessed downward to form an annular shape. The plurality of notches 449 radially connect the circumferential groove 448 to the external space of the fourth case 44.

The multiple regulating walls 461 are arranged at intervals in the circumferential direction. The number of the multiple regulating walls 461 is the same as the number of channels of the rotary valve 30. As shown in FIG. 8, the regulating wall 461 includes a regulating surface 462 perpendicular to the radial direction, and a first inclined surface 463 and a second inclined surface 464 inclined in the circumferential direction. The first inclined surface 463 has a steeper gradient in the circumferential direction than the second inclined surface 464. In the first embodiment, the first inclined surface 463 extends in the radial direction, and the angle of the first inclined surface 463 with respect to the circumferential direction is approximately 90°. The angle of the second inclined surface 464 with respect to the circumferential direction is approximately 30°. The first inclined surface 463 is connected to the rear end of the regulating surface 462 in the first circumferential direction C1, and the second inclined surface 464 is connected to the front end of the regulating surface 462 in the first circumferential direction C1. The space between adjacent regulating walls 461 is connected to the circumferential groove 448. In the following description, the space formed between two circumferentially adjacent restriction walls 461 is also referred to as the "recess 465."

3 and 4, the fifth case 45 is generally plate-shaped. As shown in FIG. 9, the fifth case 45 has a plurality of connection joints 451 (451a to 451h). The fifth case 45 also has a plurality of connection ports 452 (452a to 452h) that open to the bottom surface of the fifth case 45, and a plurality of connection paths 453 (453a to 453h) that open to the plurality of connection joints 451 at one end and connect to the plurality of connection ports 452 at the other end. The number of connection joints 451, the number of connection ports 452, and the number of connection paths 453 are the same as the number of channels of the rotary valve 30. The connection ports 452 allow gas to pass through the gas supplied from the rotary valve 30 to the air bag 21, and allow gas to pass through the gas discharged from the air bag 21 to the rotary valve 30. The plurality of connection ports 452 are arranged at equal intervals in the circumferential direction.

When the fifth case 45 is viewed from the axial direction, the connection ports 452a and 452e are formed at positions on either side of the axis passing through the center of the fifth case 45. The connection ports 452b and 452f are formed at positions on either side of the axis passing through the center of the fifth case 45. The connection ports 452c and 452g are formed at positions on either side of the axis passing through the center of the fifth case 45. The connection ports 452d and 452h are formed at positions on either side of the axis passing through the center of the fifth case 45. The axis passing through the center of the fifth case 45 coincides with the rotation axis of the switching unit 80.

As shown in Figures 3 and 4, the first piston 50 is generally cylindrical. The first piston 50 has a second retaining groove 51 that retains the second seal ring 102. The first piston 50 also has a communication passage 52 that penetrates in the axial direction. The inner diameter of the communication passage 52 is preferably smaller than the inner diameter of the supply port 416 of the first case 41, and the communication passage 52 is preferably a fine hole. In the first piston 50, the communication passage 52 may be formed at any position, and the number of communication passages 52 may be any number.

As shown in Figures 3 and 4, the second piston 60 has a support shaft 61 extending in the axial direction and a third retaining groove 62 that retains the third seal ring 103. The second piston 60 also has a communication hole 63 that passes through the center in the axial direction. The support shaft 61 is substantially cylindrical, and the outer diameter of the support shaft 61 is smaller than the inner diameter of the third through hole 433 of the third case 43. The tip of the support shaft 61 branches into multiple parts. The branched tips of the support shaft 61 are claw-shaped.

As shown in Figures 3 and 4, the rotor 70 is generally cylindrical. The rotor 70 has a pair of engagement protrusions 71 that protrude radially outward from the outer circumferential surface. The rotor 70 also has an engagement hole 72 that passes through the center in the axial direction, and a pair of engagement recesses 73 that extend axially at positions that sandwich the engagement hole 72 in the radial direction.

The engagement protrusion 71 has a substantially triangular shape when viewed from the front in the radial direction. The engagement protrusion 71 includes a first cam surface 74 that faces upward as it advances in the first circumferential direction C1, and a second cam surface 75 that faces downward as it advances in the first circumferential direction C1. The first cam surface 74 and the second cam surface 75 are connected at their tips in the first circumferential direction C1. The first cam surface 74 mainly slides against the first guide surface 434 of the third case 43, and the second cam surface 75 mainly slides against the second guide surface 445 of the fourth case 44. For this reason, it is preferable that the inclination of the first cam surface 74 with respect to the axial direction is equal to the inclination of the first guide surface 434 of the third case 43 with respect to the axial direction, and the inclination of the second cam surface 75 with respect to the axial direction is equal to the inclination of the second guide surface 445 of the fourth case 44 with respect to the axial direction. In addition, the angle between the first cam surface 74 and the second cam surface 75 is approximately 90°.

As shown in FIGS. 3 and 4 , the switching unit 80 has a switching valve 81 that switches the supply destination of air by rotating, and a valve body 82 that is arranged inside the switching valve 81 .
10 to 12, the switching valve 81 has a substantially cylindrical main body 83 and an engagement shaft 84 extending in the axial direction from the main body 83. Also, as shown in Figures 3 and 4, the switching valve 81 has a pair of engagement walls 85 extending in the axial direction from the main body 83. As shown in Figures 11 and 12, the switching valve 81 has an air supply path 86 through which gas supplied mainly to the air bladder 21 passes, an internal valve connection path 87 through which gas supplied to the air bladder 21 and gas exhausted from the air bladder 21 pass, and a first exhaust path 88 through which gas exhausted from the air bladder 21 passes.

The main body 83 includes a part of the air supply passage 86, the valve connection passage 87, the first exhaust passage 88, and a fourth retaining groove 831 that holds the fourth seal ring 104. As shown in FIG. 12, a part of the air supply passage 86 extends from the center of the main body 83 toward the engagement shaft 84. The valve connection passage 87 extends radially from the center of the main body 83 and then extends axially. Therefore, one end of the valve connection passage 87 is connected to the air supply passage 86, and the other end opens on the upper surface of the main body 83. As shown in FIG. 11 and FIG. 12, the first exhaust passage 88 extends from the center of the main body 83 in the opposite direction to the valve connection passage 87. The first exhaust passage 88 has one end connected to the valve connection passage 87 and the other end opening on the outer circumferential surface of the main body 83. The cross-sectional shape of the first exhaust passage 88 in the radial direction is approximately rectangular. The first exhaust passage 88 has a larger flow passage cross-sectional area than the air supply passage 86 and the in-valve connection passage 87. In the following description, the opening in the first exhaust passage 88 that is connected to the in-valve connection passage 87 is also referred to as the "first exhaust port 881."

As shown in FIG. 10, when the main body 83 is viewed in the axial direction, the fourth retaining groove 831 has a generally elliptical shape with the radial direction as the short side direction and the circumferential direction as the long side direction. The fourth retaining groove 831 is recessed in the axial direction from the upper surface of the main body 83. In the following description, the space surrounded by the fourth retaining groove 831, in other words, the space surrounded by the fourth seal ring 104, is also referred to as the "communication space 89." The circumferential length of the communication space 89 is set to be less than the length between adjacent connection ports 452 of the fifth case 45. In addition, the intra-valve connection path 87 opens into the communication space 89.

As shown in FIG. 12, the engagement shaft 84 includes a portion of the air supply passage 86 and a fifth retaining groove 841 that retains the fifth seal ring 105. The air supply passage 86 passes through the engagement shaft 84 in the axial direction. The fifth retaining groove 841 is provided at the tip of the engagement shaft 84. As shown in FIG. 3 and FIG. 4, the cross-sectional shape perpendicular to the axial direction of the engagement wall 85 is substantially equal to the cross-sectional shape perpendicular to the axial direction of the engagement recess 73 of the rotor 70.

11 and 12, the valve body 82 has a seal block 821 that blocks the first exhaust port 881 and a support part 822 that supports the seal block 821. The seal block 821 is substantially rectangular. The valve body 82 is preferably made of an elastomer having appropriate elasticity, such as rubber or resin. The support part 822 includes a rectangular plate-shaped base part 823 and a sliding part 824 that protrudes from the base part 823. When the surface of the base part 823 that supports the seal block 821 is the front, a groove is formed in the side of the base part 823. The cross section of the sliding part 824 perpendicular to the protruding direction is substantially elliptical. As shown in FIG. 11, the sliding part 824 includes a first sliding surface 825 and a second sliding surface 826 at the tip. The first sliding surface 825 intersects with the protruding direction of the sliding portion 824 at an angle of approximately 90°, and the second sliding surface 826 intersects with the protruding direction of the sliding portion 824 at an angle of approximately 45°. For example, the second sliding surface 826 is formed by chamfering the first sliding surface 825.

As shown in Figures 11 and 12, the valve body 82 is disposed in the first exhaust passage 88 of the switching unit 80. At this time, the seal block 821 is disposed radially inside the first exhaust passage 88, and the base 823 is disposed radially outside the first exhaust passage 88. The valve body 82 moves radially inside the first exhaust passage 88 of the switching unit 80, thereby displacing between a closed position that closes the first exhaust port 881 and an open position that opens the first exhaust port 881. When the valve body 82 is in the closed position and the pressure in the air supply passage 86 is higher than the pressure in the first exhaust passage 88, the valve body 82 is urged from the closed position toward the open position by the pressure in the air supply passage 86.

The relationships between the components of the rotary valve 30 will now be described.
As shown in Fig. 13, the first case 41, the second case 42, the third case 43, the fourth case 44, and the fifth case 45 are connected in the axial direction. At this time, as shown in Fig. 6 and Fig. 7, the third case 43 and the fourth case 44 are connected such that the positions of the first connection surface 436 and the second connection surface 447 in the circumferential direction do not coincide. In other words, the third case 43 and the fourth case 44 are connected such that the second connection surface 447 is located between the first connection surfaces 436 adjacent to each other in the circumferential direction. In addition, the first seal ring 101 is compressed between the first case 41 and the second case 42.

As shown in FIG. 13, the first piston 50 is housed in the first case 41 so as to be movable in the axial direction. The first piston 50 faces the second exhaust port 425 of the second case 42 in the axial direction. The second seal ring 102 is compressed between the first piston 50 and the first case 41. The first case 41 and the first piston 50 define a first air chamber AC1 that stores air. The first air chamber AC1 has a substantially circular plate shape, and its length in the axial direction is shorter than its length in the radial direction. Between the first piston 50 and the second case 42, the first biasing member 91 is disposed in a compressed state. Therefore, the first piston 50 is biased in a direction that reduces the volume of the first air chamber AC1, that is, downward. The first piston 50 is displaced between a closed position that closes the second exhaust port 425 and an open position that opens the second exhaust port 425. When the first piston 50 is displaced between the closed position and the open position, the volume of the first air chamber AC1 changes. The first biasing member 91 may be any member that is elastically deformable, and in the first embodiment, it is a coil spring. The first biasing member 91 is an example of a "biasing member."

The second piston 60 is accommodated in the second case 42, the third case 43, and the fourth case 44 so as to be movable in the axial direction. At this time, the third seal ring 103 is compressed between the second piston 60 and the second case 42. The second case 42 and the first piston 50 and the second piston 60 define a second air chamber AC2 as an "air chamber" for storing air. The volumes of the first air chamber AC1 and the second air chamber AC2 change depending on the positions of the first piston 50 and the second piston 60, respectively, but the volume of the second air chamber AC2 is always larger than the volume of the first air chamber AC1. Between the second piston 60 and the third bottom wall 431 of the third case 43, the second biasing member 92 is arranged in a compressed state. Therefore, the second piston 60 is biased in a direction that reduces the volume of the second air chamber AC2, that is, downward. When the second piston 60 is displaced in the axial direction, the volume of the second air chamber AC2 changes. The second biasing member 92 may be any member that is elastically deformable, and in the first embodiment is a coil spring.

The rotor 70 is supported by the support shaft 61 of the second piston 60 so that it can move axially together with the second piston 60 and rotate circumferentially relative to the second piston 60. In more detail, the support shaft 61 of the second piston 60 is inserted into the engagement hole 72 of the rotor 70, so that the rotor 70 is supported by the support shaft 61 of the second piston 60. At this time, the support shaft 61 of the second piston 60 and the rotor 70 engage with each other by a so-called snap fit that utilizes the elastic deformation of the tip of the support shaft 61 of the second piston 60.

The rotor 70 is housed in the third case 43 and the fourth case 44. At this time, the engagement protrusion 71 of the rotor 70 is disposed in the axial direction between the first guide surface 434 and the first auxiliary guide surface 435 of the third case 43 and the second guide surface 445 and the second auxiliary guide surface 446 of the fourth case 44. In other words, the movement range of the rotor 70 in the axial direction and the circumferential direction is limited to the first guide surface 434, the first auxiliary guide surface 435, and the first connecting surface 436 of the second case 42 and the second guide surface 445, the second auxiliary guide surface 446, and the second connecting surface 447 of the third case 43.

The switching unit 80 is supported by the second piston 60 so as to be rotatable in the circumferential direction together with the rotor 70. More specifically, the switching unit 80 is supported by the second piston 60 by inserting the engagement shaft 84 of the switching unit 80 into the communication hole 63 of the support shaft 61 of the second piston 60. At this time, the air supply passage 86 of the switching unit 80 is connected to the second air chamber AC2 via the communication hole 63 of the support shaft 61.

In addition, since the main body 83 of the switching unit 80 is sandwiched between the fourth case 44 and the fifth case 45 in the axial direction, the switching unit 80 cannot move axially relative to the case 40. Therefore, when the second piston 60 moves axially, the second piston 60 moves relative to the switching unit 80. In addition, when the switching unit 80 is housed in the case 40, the fourth seal ring 104 is compressed between the fifth case 45 and the switching unit 80, and the fifth seal ring 105 is compressed between the engagement shaft 84 of the switching unit 80 and the support shaft 61 of the second piston 60.

The pair of engagement walls 85 of the switching unit 80 enter and exit the pair of engagement recesses 73 of the rotor 70 depending on the axial position of the rotor 70. The switching unit 80 rotates in the circumferential direction due to the torque transmitted from the rotor 70 via the pair of engagement walls 85. In other words, the circumferential position of the switching unit 80 is determined by the circumferential position of the rotor 70.

Although not shown in FIG. 13 below, when housed in the fourth case 44, the first exhaust path 88 of the switching unit 80 is connected to one of the recesses 465 of the fourth case 44. In other words, the first exhaust path 88 of the switching unit 80 is always connected to the external space via one of the recesses 465. In addition, the communication space 89 of the switching unit 80 is only connected to one of the multiple connection ports 452 of the fifth case 45. In other words, the communication space 89 of the switching unit 80 is not connected to two or more of the multiple connection ports 452 at the same time.

Air is supplied to the first air chamber AC1 via the supply joint 413 of the first case 41, and air is discharged through the communication passage 52 of the first piston 50. In other words, air supplied to the first air chamber AC1 passes through the supply port 416 of the supply joint 413, and air discharged from the first air chamber AC1 passes through the communication passage 52 of the first piston 50.

Air is supplied to the second air chamber AC2 through the communication passage 52 of the first piston 50, and air is exhausted through the first exhaust path 88 of the switching unit 80 or the second exhaust path 423 of the second case 42. In other words, air supplied to the second air chamber AC2 passes through the communication passage 52 of the first piston 50, and air exhausted from the second air chamber AC2 passes through the first exhaust port 881 or the second exhaust port 425. Furthermore, in the case 40, air moving between the second air chamber AC2 and any of the air bags 21 passes through any of the connection ports 452.

The operation of the first embodiment will be described below with reference to the cross-sectional view of the rotary valve 30 taken along the cross-sectional line shown in FIG.
First, the operation of the rotary valve 30 when air is supplied from the pump 22 will be described.

In more detail, the action of the rotary valve 30 when the pump 22 is driven while the rotary valve 30 is in the initial state shown in Figures 15, 16, and 17 will be described. Note that the initial state of the rotary valve 30 shown in Figures 15, 16, and 17 is one example, and the state of the rotary valve 30 when the pump 22 starts to be driven may change depending on the state of the rotary valve 30 when the pump 22 was previously stopped.

As shown in FIG. 15, in the initial state, the first piston 50 is at its lowest position. In other words, the first piston 50 is in an open position that opens the second exhaust port 425 of the second case 42. Therefore, the second air chamber AC2 is connected to the outside space via the second exhaust path 423. Also, in the initial state, the second piston 60 is at its lowest position. Therefore, the rotor 70 supported by the second piston 60 is also at its lowest position. As shown in FIG. 16, in the initial state, the engagement protrusion 71 of the rotor 70 is located at the boundary between the first guide surface 434 and the first connection surface 436 of the third case 43.

As shown in FIG. 16, when the rotor 70 is located at the boundary between the first guide surface 434 and the first connection surface 436 of the third case 43, the switching unit 80 is located in the position shown in FIG. 17. In other words, the valve body 82 of the switching unit 80 is in contact with the regulating surface 462 of the regulating wall 461 of the fourth case 44 and is located in a closed position that closes the first exhaust port 881 of the switching unit 80.

15 and 17, in the initial state, the second air chamber AC2 is connected to the pump 22 through the communication passage 52 of the first piston 50, the first air chamber AC1, and the supply joint 413 of the first case 41. The second air chamber AC2 is also connected to the air bag 21a through the communication hole 63 of the second piston 60, the air supply passage 86, the valve internal connection passage 87, and the communication space 89 of the switching unit 80, and the connection passage 453a of the fifth case 45. As shown in FIG. 17, the second air chamber AC2 is not connected to the outside space through the first exhaust passage 88 when the valve body 82 of the switching unit 80 is in the closed position. On the other hand, as shown in FIG. 15, the second air chamber AC2 is connected to the outside space through the second exhaust passage 423 when the first piston 50 is in the open position. Therefore, the pressure in the air bag 21a is equal to atmospheric pressure, and the air bag 21a is contracted.

As shown in FIG. 18, when the pump 22 is driven, air is supplied to the first air chamber AC1. Then, air is supplied from the first air chamber AC1 to the second air chamber AC2 through the communication passage 52 of the first piston 50, and air flows out from the second air chamber AC2 to the outside space through the second exhaust path 423. Here, since the inner diameter of the communication passage 52 of the first piston 50 is small, the supply flow rate of air from the first air chamber AC1 to the second air chamber AC2 through the communication passage 52 is less than the supply flow rate of air from the outside space to the first air chamber AC1 through the supply joint 413. In other words, the communication passage 52 of the first piston 50 limits the supply flow rate of air from the first air chamber AC1 to the second air chamber AC2. Therefore, the pressure of the first air chamber AC1 gradually increases depending on the elapsed time after the pump 22 is driven.

When the product of the pressure in the first air chamber AC1 and the pressure-receiving area of the first piston 50, i.e., the force pushing up the first piston 50, becomes greater than the force with which the first biasing member 91 biases the first piston 50, i.e., the force pushing down the first piston 50, the first piston 50 rises. In other words, the first piston 50 displaces in a direction that increases the volume of the first air chamber AC1 and decreases the volume of the second air chamber AC2. Then, when the first piston 50 contacts the second bottom wall 421 of the second case 42, the first piston 50 is positioned in a closed position that closes the second exhaust port 425 of the second case 42.

When the first piston 50 is in the closed position, the air supplied from the external space to the first air chamber AC1 is supplied to the second air chamber AC2 almost as it is, and air does not flow out from the second air chamber AC2 to the external space through the second exhaust path 423. As a result, the air supplied to the second air chamber AC2 is supplied to the air bag 21a through the communication hole 63 of the second piston 60, the air supply path 86, the internal valve connection path 87, and the communication space 89 of the switching unit 80, and the connection path 453a of the fifth case 45. In other words, the air bag 21a expands. After that, when the air bag 21a expands to its limit, the pressure in the second air chamber AC2 begins to increase.

As shown in FIG. 19, when the product of the pressure in the second air chamber AC2 and the pressure-receiving area of the second piston 60, i.e., the force pushing up the second piston 60, becomes greater than the force with which the second biasing member 92 biases the second piston 60, i.e., the force pushing down the second piston 60, the second piston 60 rises. At this time, the second piston 60 rises together with the rotor 70.

20, when the rotor 70 rises, the engagement protrusion 71 of the rotor 70 transitions from a state in which it is engaged with the third case 43 to a state in which it is engaged with the fourth case 44. In detail, as shown by the dashed arrow in FIG. 20, the state in which the first cam surface 74 of the engagement protrusion 71 of the rotor 70 contacts the first guide surface 434 of the third case 43 changes to a state in which the second cam surface 75 of the engagement protrusion 71 of the rotor 70 contacts the second guide surface 445 of the fourth case 44. If the second piston 60 continues to rise even after the second cam surface 75 of the engagement protrusion 71 of the rotor 70 contacts the second guide surface 445 of the fourth case 44, as shown by the solid arrow in FIG. 20, the second cam surface 75 of the engagement protrusion 71 of the rotor 70 slides against the second guide surface 445 of the fourth case 44. In other words, the rotor 70 rotates in the second circumferential direction C2 while rising.

When the rotor 70 rotates, the switching unit 80 rotates with the rotor 70, so when the rotor 70 moves to the position shown by the solid line in FIG. 20, the switching unit 80 rotates to the position shown in FIG. 21. In other words, the switching unit 80 rotates in the second circumferential direction C2 when the pressure in the second air chamber AC2 increases. Also, the switching unit 80 rotates to the position shown in FIG. 21 before the engagement protrusion 71 of the rotor 70 contacts the second connection surface 447 of the fourth case 44.

21, the sliding portion 824 of the valve body 82 changes from a state in which it faces the regulating surface 462 of the regulating wall 461 of the fourth case 44 to a state in which it faces the recess 465 located in the second circumferential direction C2 of the regulating wall 461 in the radial direction. In other words, the sliding portion 824 of the valve body 82 changes from a state in which it engages with the regulating surface 462 of the regulating wall 461 to a state in which it does not engage with the regulating surface 462 of the regulating wall 461.

Considering the state immediately before the switching unit 80 rotates to the position shown in FIG. 21, the valve body 82 is in a closed position where it closes the second exhaust port 425, at the point where the sliding portion 824 of the valve body 82 slides against the restricting surface 462 of the restricting wall 461 of the fourth case 44. Therefore, in the above state, the valve body 82 is biased by a force corresponding to the pressure difference between the air supply path 86 and the first exhaust path 88 of the switching unit 80. In other words, in the above state, a force is acting on the valve body 82 to press the valve body 82 radially against the restricting surface 462 of the restricting wall 461.

21, when the sliding portion 824 of the valve body 82 no longer slides against the restricting surface 462 of the restricting wall 461 of the fourth case 44 in the radial direction, the valve body 82 is forcefully displaced to the open position. In the first embodiment, since the first inclined surface 463 of the restricting wall 461 extends in the radial direction, when the valve body 82 displaces from the closed position to the open position, the sliding portion 824 of the valve body 82 and the first inclined surface 463 of the restricting wall 461 only slightly slide against each other.

21, even when the valve body 82 is in the open position, the valve internal connection path 87 of the switching unit 80 is connected to the connection path 453a of the fifth case 45 via the communication space 89 of the switching unit 80. In other words, in the state shown in FIG. 21, the air bag 21a and the second air chamber AC2 are connected. Therefore, as shown in FIG. 19, when the valve body 82 is in the open position, the air supplied from the first air chamber AC1 to the second air chamber AC2 and the air stored in the air bag 21a are exhausted to the outside space from the first exhaust path 88 of the switching unit 80. Therefore, the pressure in the second air chamber AC2 decreases, and the air bag 21a contracts.

As shown in Figures 22 and 23, when the product of the pressure in the second air chamber AC2 and the pressure-receiving area of the second piston 60, i.e., the force pushing up the second piston 60, becomes smaller than the force with which the second biasing member 92 biases the second piston 60, i.e., the force pushing down the second piston 60, the second piston 60 descends. At this time, the second piston 60 descends together with the rotor 70.

24, when the rotor 70 descends, the engagement protrusion 71 of the rotor 70 transitions from a state in which it engages with the fourth case 44 to a state in which it engages with the third case 43. In detail, as shown by the dashed arrow in FIG. 24, the second cam surface 75 of the engagement protrusion 71 of the rotor 70 contacts the second guide surface 445 of the fourth case 44, and the first cam surface 74 of the engagement protrusion 71 of the rotor 70 contacts the first guide surface 434 of the third case 43. If the second piston 60 continues to descend even after the first cam surface 74 of the engagement protrusion 71 of the rotor 70 contacts the first guide surface 434 of the third case 43, the first cam surface 74 of the engagement protrusion 71 of the rotor 70 slides against the first guide surface 434 of the third case 43, as shown by the solid arrow in FIG. 24. In other words, the rotor 70 rotates in the second circumferential direction C2 while descending.

When the rotor 70 rotates, the switching unit 80 rotates together with the rotor 70 in the second circumferential direction C2. As shown in FIG. 25, when the first cam surface 74 of the engagement protrusion 71 of the rotor 70 slides against the first guide surface 434 of the third case 43, the sliding portion 824 of the valve body 82 faces the recess 465 of the fourth case 44 in the radial direction, and the sliding portion 824 of the valve body 82 faces the regulating wall 461 located in the second circumferential direction C2 of the recess 465. At this time, the sliding portion 824 of the valve body 82 slides against the second inclined surface 464 of the regulating wall 461 of the fourth case 44 as it rotates in the second circumferential direction C2. Therefore, the sliding portion 824 of the valve body 82 moves inward in the radial direction as the switching unit 80 rotates in the second circumferential direction C2. That is, the sliding portion 824 of the valve body 82 is displaced from the open position toward the closed position. Here, the part of the sliding portion 824 of the valve body 82 that slides against the second inclined surface 464 of the restriction wall 461 is the second sliding surface 826 that is inclined in the radial direction like the second inclined surface 464. Therefore, the sliding portion 824 of the valve body 82 can slide smoothly against the second inclined surface 464 of the restriction wall 461.

As shown by the solid line in FIG. 24, when the engagement projection 71 of the rotor 70 moves to the boundary between the first guide surface 434 and the first connection surface 436 of the third case 43, the valve body 82 is in a closed position to close the second exhaust port 425, as shown in FIG. 26. In other words, the connection port 452a of the fifth case 45 is no longer connected to the communication space 89 of the valve body 82, while the connection port 452b of the fifth case 45 is connected to the communication space 89 of the valve body 82.

As a result, as shown in FIG. 22, the connection path 453a connected to the air bag 21a is no longer connected to the second air chamber AC2, and as shown in FIG. 23, the connection path 453b connected to the air bag 21b is connected to the second air chamber AC2. Therefore, in the state shown in FIG. 22 and FIG. 23, if the supply of air from the pump 22 to the rotary valve 30 continues, the air bag 21b will inflate in the same way as the air bag 21a described above.

Next, if the supply of air from the pump 22 to the rotary valve 30 continues, the air bag 21b contracts in the same manner as the air bag 21a described above. Thereafter, if the supply of air from the pump 22 to the rotary valve 30 continues, the air bags 21 that expand and contract are switched in sequence to air bags 21c, 21d, and 21e. When the expansion and contraction of air bag 21h is completed, air bag 21a expands and contracts again.

In this way, the rotary valve 30 of the first embodiment switches the air supply state to the multiple air bags 21 during one rotation of the switching unit 80 as follows. That is, the switching unit 80 switches from a first air supply state in which air is supplied to the air bag 21a via the connection port 452a to a first exhaust state in which air is exhausted from the air bag 21a via the connection port 452a.

Then, the switching unit 80 switches to a second air supply state in which air is supplied to the air bag 21b via the connection port 452b, and then switches to a second exhaust state in which air is exhausted from the air bag 21b via the connection port 452b.

Then, the switching unit 80 switches to a third air supply state in which air is supplied to the air bag 21c via the connection port 452c, and then switches to a third exhaust state in which air is exhausted from the air bag 21c via the connection port 452c.

Next, the switching unit 80 switches to a fourth air supply state in which air is supplied to the air bag 21d via the connection port 452d, and then switches to a fourth exhaust state in which air is exhausted from the air bag 21d via the connection port 452d.

Then, the switching unit 80 switches to a fifth air supply state in which air is supplied to the air bag 21e via the connection port 452e, and then switches to a fifth exhaust state in which air is exhausted from the air bag 21e via the connection port 452e.

Then, the switching unit 80 switches to a sixth air supply state in which air is supplied to the air bag 21f via the connection port 452f, and then switches to a sixth exhaust state in which air is exhausted from the air bag 21f via the connection port 452f.

Next, the switching unit 80 switches to a seventh air supply state in which air is supplied to the air bag 21g via the connection port 452g, and then switches to a seventh exhaust state in which air is exhausted from the air bag 21g via the connection port 452g.

Then, the switching unit 80 switches to the eighth air supply state in which air is supplied to the air bag 21h via the connection port 452h, and then switches to the eighth exhaust state in which air is exhausted from the air bag 21h via the connection port 452h. In this way, the switching unit 80 switches between the "16" air supply state and exhaust state during one rotation.

In addition, in the first embodiment, when air bag 21a is regarded as the "first air bag" and connection port 452a is regarded as the "first connection port", air bag 21e corresponds to the "second air bag" and connection port 452e corresponds to the "second connection port". When air bag 21b is regarded as the "first air bag" and connection port 452b is regarded as the "first connection port", air bag 21f corresponds to the "second air bag" and connection port 452f corresponds to the "second connection port". When air bag 21c is regarded as the "first air bag" and connection port 452c is regarded as the "first connection port", air bag 21g corresponds to the "second air bag" and connection port 452g corresponds to the "second connection port". Furthermore, when air bag 21d is considered to be the "first air bag" and connection port 452d is considered to be the "first connection port," air bag 21h corresponds to the "second air bag" and connection port 452h corresponds to the "second connection port."

Next, the operation of the rotary valve 30 when the pump 22 stops supplying air to the rotary valve 30 will be described.
As described above, in the rotary valve 30, the valve element 82 reciprocates between the closed position and the open position in a situation in which air is supplied from the pump 22. Therefore, depending on the timing at which the supply of air to the rotary valve 30 is stopped, the supply of air may be stopped when the valve element 82 is in the closed position, or the supply of air may be stopped when the valve element 82 is in the open position.

For example, if the supply of air from the pump 22 is stopped when the valve body 82 is in the closed position, the air bag 21 that is connected to the valve internal connection path 87 of the switching unit 80 remains inflated. In this case, the user sitting on the seat 10 may feel uncomfortable, and the air bag 21 may be more susceptible to deterioration over time if the air bag 21 remains in an inflated state for a long period of time. Therefore, in the above case, the rotary valve 30 of the first embodiment discharges air from the air bag 21 as follows.

The timing at which the air supply to the rotary valve 30 is stopped may include when the user turns off the ignition of the vehicle and when the user ends the massage by the massage system 20.

Figure 27 shows a state in which the operation of the pump 22 is stopped while the valve body 82 of the switching unit 80 is in the closed position and the air bag 21b is inflated. Immediately after the operation of the pump 22 is stopped, the pressure in the first air chamber AC1 is higher than the pressure in the second air chamber AC2, and the first piston 50 is in the closed position that closes the second exhaust port 425 of the second case 42.

A short time after the pump 22 is stopped, air flows from the first air chamber AC1 to the second air chamber AC2, as shown by the solid arrow, and the pressure in the first air chamber AC1 and the pressure in the second air chamber AC2 become approximately equal. Then, the first piston 50 descends due to the biasing force of the first biasing member 91. In other words, the first piston 50 is displaced in a direction that reduces the volume of the first air chamber AC1 and increases the volume of the second air chamber AC2. As a result, the first piston 50 is positioned in an open position that opens the second exhaust port 425 of the second case 42.

28, when the first piston 50 is in the open position, the second air chamber AC2 is connected to the outside space through the second exhaust passage 423 of the second case 42. Therefore, the air stored in the air bag 21b is discharged to the outside space through the connection passage 453b of the fifth case 45, the air supply passage 86, the valve internal connection passage 87 and the communication space 89 of the switching unit 80, the communication hole 63 of the second piston 60, the second air chamber AC2, and the second exhaust passage 423 of the second case 42. Thus, even if the operation of the pump 22 is stopped when the valve body 82 of the switching unit 80 is in the closed position and the air bag 21b is inflated, the air bag 21b is not left in an inflated state. The same applies to the other air bags 21.

On the other hand, when the valve body 82 is in the open position, all of the air bags 21 are deflated. Therefore, when the air supply from the pump 22 is stopped, the above-mentioned problems do not occur.

The effects of the first embodiment will be described.
(1) When the switching unit 80 rotates with an increase in the pressure in the second air chamber AC2, the valve body 82 of the switching unit 80 goes from a state in which it cannot be displaced to the open position by the restricting wall 461 of the case 40 to a state in which it can be displaced to the open position by the recess 465 of the case 40. Therefore, the valve body 82 of the switching unit 80 is likely to be displaced from the closed position to the open position in a short period of time, and the pressure in the second air chamber AC2 is unlikely to decrease while the valve body 82 of the switching unit 80 is displaced from the open position to the closed position. Therefore, the rotary valve 30 can stably switch between a state in which air is supplied to the air bag 21 and a state in which air is discharged from the air bag 21.

(2) In the rotary valve 30, the first inclined surface 463 has a steeper inclination in the direction of rotation of the switching unit 80 than the second inclined surface 464, which makes it easier for the valve body 82 of the switching unit 80 to move from the closed position to the open position in a short period of time.

(3) The first inclined surface 463 of the rotary valve 30 extends radially of the switching unit 80. This makes it easier for the valve body 82 of the switching unit 80 of the rotary valve 30 to move from the closed position to the open position in a shorter period of time.

(4) The rotary valve 30 prevents the air bag 21 from remaining inflated, regardless of the timing at which the supply of air from the pump 22 is stopped. As a result, the rotary valve 30 can prevent the user sitting in the seat 10 from becoming uncomfortable. In addition, the rotary valve 30 can prevent the air bag 21 from easily deteriorating over time, which would otherwise occur if the air bag 21 remained inflated for a long period of time.

(5) In the rotary valve 30 , the communication passage 52 is formed in the first piston 50 , so that the structure of the device can be simplified compared to a case in which the communication passage 52 is formed in the case 40 .
(6) The rotary valve 30 includes the first biasing member 91 that biases the first piston 50 in a direction that decreases the volume of the first air chamber AC1. This makes it easier for the rotary valve 30 to move the first piston 50 from the closed position to the open position when the supply of air is stopped. This allows the rotary valve 30 to have high reliability in contracting the air bag 21 when the supply of air is stopped.

(7) The rotary valve 30 can sequentially inflate and deflate the eight air bladders 21a to 21h while the switching unit 80 makes one rotation.
Second Embodiment
The rotary valve according to the second embodiment will be described below. The rotary valve according to the second embodiment is different from the rotary valve according to the first embodiment in the configuration of the switching unit and the driving mode of the pump. Therefore, in the following description, the same reference numerals are used for the configurations common to the first embodiment, and the description thereof will be omitted.

As shown in Figures 29 and 30, the switching unit 80A of the rotary valve 30A has a switching valve 81 that switches the supply destination of air by rotating, and a valve body 82A arranged inside the switching valve 81. The switching valve 81 has a main body 83A, an engagement shaft 84, a pair of engagement walls 85, an air supply passage 86, an internal valve connection passage 87, and a first exhaust passage 88.

The main body 83A includes a part of the air supply passage 86, the valve internal connection passage 87, the first exhaust passage 88, a fourth retaining groove 831, and a locking hole 832 that connects to the first exhaust passage 88. The locking hole 832 has a substantially rectangular shape when the main body 83A is viewed from the axial direction. The locking hole 832 extends axially from the first exhaust passage 88 and partially penetrates the main body 83A.

The valve body 82A has a seal block 821A that blocks the first exhaust port 881, and a support portion 822A that supports the seal block 821A. The seal block 821A is generally rectangular. The seal block 821A is preferably made of an elastomer having appropriate elasticity, such as rubber or resin. The support portion 822A includes a base portion 823A and an engagement portion 827 that protrudes from the base portion 823A. The engagement portion 827 is in the form of a claw that can be engaged with an engagement hole 832 in the main body portion 83A.

As shown in FIG. 30, the valve body 82A is disposed in the first exhaust passage 88 of the switching unit 80A. At this time, with the seal block 821A closing the first exhaust port 881, the locking portion 827 locks into the locking hole 832. That is, in the second embodiment, the valve body 82A remains in the closed position that closes the first exhaust port 881 without moving within the first exhaust passage 88. Therefore, the valve body 82A remains in the closed position even when the switching unit 80A rotates.

The switching unit 80A is supported by the second piston 60 so as to be rotatable in the circumferential direction together with the rotor 70, as in the first embodiment. The switching unit 80A is housed in the case 40 so as not to be able to move in the axial direction relative to the case 40.

The operation of the second embodiment will be described.
First, a description will be given of the operation of the rotary valve 30A when air is supplied from the pump 22. In the description of the operation, a cross-sectional view of the rotary valve 30A based on the cross-sectional indication line shown in FIG.

In the following description, the initial state of the rotary valve 30A is defined as the state in which the engagement protrusion 71 of the rotor 70 is located at the boundary between the first guide surface 434 and the first connection surface 436 of the third case 43, as shown by the solid line in FIG. 32, and the second air chamber AC2 and the air bag 21a are connected, as shown in FIG. 33. The operation of the rotary valve 30A when the pump 22 is driven and stopped in the initial state will be described.

As shown in FIG. 33, in the initial state, the first piston 50 is at its lowest position. In other words, the first piston 50 is in an open position that opens the second exhaust port 425 of the second case 42. Therefore, the second air chamber AC2 is connected to the outside space via the second exhaust path 423. Also, in the initial state, the second piston 60 is at its lowest position. Therefore, the rotor 70 supported by the second piston 60 is also at its lowest position. As described above, in the initial state, the engagement protrusion 71 of the rotor 70 is located at the boundary between the first guide surface 434 and the first connection surface 436 of the third case 43, as shown by the solid line in FIG. 32.

33, in the initial state, the second air chamber AC2 is connected to the pump 22 through the communication passage 52 of the first piston 50, the first air chamber AC1, and the supply joint 413 of the first case 41. The second air chamber AC2 is also connected to the air bag 21a through the communication hole 63 of the second piston 60, the air supply passage 86, the valve internal connection passage 87, and the communication space 89 of the switching unit 80A, and the connection passage 453a of the fifth case 45. In the second embodiment, the second air chamber AC2 is not connected to the outside space through the first exhaust passage 88 because the valve body 82A of the switching unit 80A is always in the closed position. On the other hand, the second air chamber AC2 is connected to the outside space through the second exhaust passage 423 because the first piston 50 is in the open position. Therefore, the pressure in the air bag 21a is equal to the atmospheric pressure, and the air bag 21a is contracted.

As shown in FIG. 34, when the pump 22 is driven, air is supplied to the first air chamber AC1. Then, air is supplied from the first air chamber AC1 to the second air chamber AC2 through the communication passage 52 of the first piston 50, and air flows out from the second air chamber AC2 to the outside space through the second exhaust path 423. Here, since the inner diameter of the communication passage 52 of the first piston 50 is small, the supply flow rate of air from the first air chamber AC1 to the second air chamber AC2 through the communication passage 52 is less than the supply flow rate of air from the outside space to the first air chamber AC1 through the supply joint 413. In other words, the communication passage 52 of the first piston 50 limits the supply flow rate of air from the first air chamber AC1 to the second air chamber AC2. Therefore, the pressure of the first air chamber AC1 gradually increases depending on the elapsed time after the pump 22 is driven.

When the product of the pressure in the first air chamber AC1 and the pressure-receiving area of the first piston 50, i.e., the force pushing up the first piston 50, becomes greater than the force with which the first biasing member 91 biases the first piston 50, i.e., the force pushing down the first piston 50, the first piston 50 rises. In other words, the first piston 50 displaces in a direction that increases the volume of the first air chamber AC1 and decreases the volume of the second air chamber AC2. Then, when the first piston 50 contacts the second bottom wall 421 of the second case 42, the first piston 50 is positioned in a closed position that closes the second exhaust port 425 of the second case 42.

When the first piston 50 is in the closed position, the air supplied from the external space to the first air chamber AC1 is supplied to the second air chamber AC2 almost as it is, and air does not flow out from the second air chamber AC2 to the external space through the second exhaust path 423. As a result, the air supplied to the second air chamber AC2 is supplied to the air bag 21a through the communication hole 63 of the second piston 60, the air supply path 86, the internal valve connection path 87, and the communication space 89 of the switching part 80A, and the connection path 453a of the fifth case 45. In other words, the air bag 21a expands. After that, when the air bag 21a expands to its limit, the pressure in the second air chamber AC2 begins to increase.

As shown in FIG. 35, when the product of the pressure in the second air chamber AC2 and the pressure-receiving area of the second piston 60, i.e., the force pushing up the second piston 60, becomes greater than the force with which the second biasing member 92 biases the second piston 60, i.e., the force pushing down the second piston 60, the second piston 60 rises. At this time, the second piston 60 rises together with the rotor 70.

32, when the rotor 70 rises, the engagement protrusion 71 of the rotor 70 transitions from a state in which it engages with the third case 43 to a state in which it engages with the fourth case 44. In detail, as shown by the dashed line arrow in FIG. 32, the state in which the first cam surface 74 of the engagement protrusion 71 of the rotor 70 contacts the first guide surface 434 of the third case 43 changes to a state in which the second cam surface 75 of the engagement protrusion 71 of the rotor 70 contacts the second guide surface 445 of the fourth case 44. If the second piston 60 continues to rise even after the second cam surface 75 of the engagement protrusion 71 of the rotor 70 contacts the second guide surface 445 of the fourth case 44, as shown by the dashed line arrow in FIG. 32, the second cam surface 75 of the engagement protrusion 71 of the rotor 70 slides against the second guide surface 445 of the fourth case 44. In other words, the rotor 70 rotates in the second circumferential direction C2 while rising.

When the rotor 70 rotates, the switching unit 80A rotates with the rotor 70. That is, the switching unit 80A rotates in the second circumferential direction C2 when the pressure in the second air chamber AC2 increases. As shown by the dashed line in FIG. 32, when the engagement protrusion 71 of the rotor 70 contacts the second connection surface 447 of the fourth case 44, the rotor 70 cannot rotate. That is, the switching unit 80A cannot rotate either. In this state, the connection port 452a of the fifth case 45 remains connected to the communication space 89 of the valve body 82A. In this way, when the pressure in the second air chamber AC2 increases, the switching unit 80A rotates while maintaining the connection port 452a open and the other connection ports 452b to 452h closed.

When the amount of air supplied to the air bag 21a becomes sufficient, the operation of the pump 22 is stopped. Immediately after the operation of the pump 22 is stopped, the pressure in the first air chamber AC1 is higher than the pressure in the second air chamber AC2, and the first piston 50 is in the closed position that closes the second exhaust port 425 of the second case 42.

A short time after the pump 22 is stopped, the pressure in the first air chamber AC1 transitions from a state in which the pressure in the first air chamber AC1 is higher than the pressure in the second air chamber AC2 to a state in which the pressure difference between the first air chamber AC1 and the second air chamber AC2 is eliminated. Then, the first piston 50 descends due to the biasing force of the first biasing member 91. In other words, the first piston 50 is displaced in a direction that reduces the volume of the first air chamber AC1 and in a direction that increases the volume of the second air chamber AC2. As a result, the first piston 50 is positioned in an open position that opens the second exhaust port 425 of the second case 42.

As shown in FIG. 36, when the first piston 50 is in the open position, the second air chamber AC2 is connected to the outside space via the second exhaust passage 423 of the second case 42. Therefore, the air stored in the air bag 21b is discharged to the outside space via the connection passage 453a of the fifth case 45, the air supply passage 86 of the switching unit 80A, the internal valve connection passage 87 and the communication space 89, the communication hole 63 of the second piston 60, the second air chamber AC2, and the second exhaust passage 423 of the second case 42. Therefore, the pressure in the second air chamber AC2 decreases, and the air bag 21a contracts.

As shown in Figures 37 and 38, when the product of the pressure in the second air chamber AC2 and the pressure-receiving area of the second piston 60, i.e., the force pushing up the second piston 60, becomes smaller than the force with which the second biasing member 92 biases the second piston 60, i.e., the force pushing down the second piston 60, the second piston 60 descends. At this time, the second piston 60 descends together with the rotor 70.

As shown by the two-dot chain line arrow in FIG. 32, when the rotor 70 descends, the engagement protrusion 71 of the rotor 70 transitions from a state in which it engages with the fourth case 44 to a state in which it engages with the third case 43. In detail, the state in which the second cam surface 75 of the engagement protrusion 71 of the rotor 70 contacts the second guide surface 445 of the fourth case 44 changes to a state in which the first cam surface 74 of the engagement protrusion 71 of the rotor 70 contacts the first guide surface 434 of the third case 43. If the second piston 60 continues to descend even after the first cam surface 74 of the engagement protrusion 71 of the rotor 70 contacts the first guide surface 434 of the third case 43, the first cam surface 74 of the engagement protrusion 71 of the rotor 70 slides against the first guide surface 434 of the third case 43. In other words, the rotor 70 rotates in the second circumferential direction C2 while descending.

When the engagement projection 71 of the rotor 70 moves to the boundary between the first guide surface 434 and the first connection surface 436 of the third case 43, the rotor 70 cannot rotate. In other words, the switching unit 80A cannot rotate either. In this state, the connection port 452a of the fifth case 45 is no longer connected to the communication space 89 of the valve body 82A, while the connection port 452b of the fifth case 45 is connected to the communication space 89 of the valve body 82A. In this way, when the pressure of the second air chamber AC2 decreases, the switching unit 80A rotates so that the connection port 452a changes from an open state to a closed state, and the connection port 452b adjacent to the connection port 452a in the second circumferential direction C2 changes from a closed state to an open state. At this time, the other connection ports 452c to 452h are maintained in a closed state.

As a result, as shown in FIG. 37, the connection path 453a connected to the air bag 21a is no longer connected to the second air chamber AC2, and as shown in FIG. 38, the connection path 453b connected to the air bag 21b is connected to the second air chamber AC2. Therefore, in the state shown in FIG. 37 and FIG. 38, when the supply of air from the pump 22 to the rotary valve 30A is resumed, the air bag 21b expands in the same manner as the air bag 21a. Next, when the driving of the pump 22 is stopped, the air bag 21b contracts in the same manner as the air bag 21a. In this way, the driving and stopping of the pump 22 are alternately performed, and the air bag 21 that expands and contracts is switched in sequence between the air bag 21c, the air bag 21d, and the air bag 21e. When the inflation and contraction of the air bag 21h is completed, the air bag 21a expands and contracts again.

In the second embodiment, when the air bag 21a is regarded as the "first air bag" and the connection port 452a is regarded as the "first connection port," the connection port 452b adjacent to the connection port 452a in the second circumferential direction C2 corresponds to the "second connection port," and the air bag 21b connected to the connection port 452b corresponds to the "second air bag."

As described above, in the rotary valve 30A according to the second embodiment, when the operation of the pump 22 is stopped, air is discharged from the air bag 21, which was the destination of the air supply. In other words, if the operation of the pump 22 is continued, the internal pressure of the air bag 21 increases, and the rotary valve 30A can increase the force with which the air bag 21 presses against the occupant's body. Therefore, the rotary valve 30A according to the second embodiment can adjust the force with which the air bag 21 presses against the occupant's body by controlling the operation time of the pump 22. Below, a method for adjusting the force with which the air bag 21 presses against the occupant's body, in other words, the intensity of the massage, will be described.

In FIG. 39, the solid lines show the driving mode of the pump 22 when the occupant's body is massaged relatively strongly, and the dashed lines show the driving mode of the pump 22 when the occupant's body is massaged relatively weakly.

As shown by the solid line in FIG. 39, when the occupant is massaged strongly, one cycle is repeated in which the pump 22 is driven for the first drive time Ton1 and then stopped for the stop time Toff. On the other hand, as shown by the dashed line, when the occupant is massaged weakly, one cycle is repeated in which the pump 22 is driven for the second drive time Ton2, which is shorter than the first drive time Ton1, and then stopped for the stop time Toff. In either case, one air bag 21 is inflated and deflated during one cycle of the first drive time Ton1 or the second drive time Ton2 and the stop time Toff. When the pump 22 is driven for the first drive time Ton1, the amount of air supplied to the air bag 21 is greater than when the pump 22 is driven for the second drive time Ton2. In this respect, when the intensity of the massage is changed, the amount of air supplied to the air bag 21 is changed.

As shown in FIG. 39, the combined time of the first drive time Ton1 and the stop time Toff is longer than the combined time of the second drive time Ton2 and the stop time Toff, so that when the occupant is massaged strongly, it takes longer to massage the entire body of the occupant than when the occupant is massaged weakly. In other words, it takes longer to inflate and deflate all of the air bags 21.

Here, the time required from when the pump 22 starts to be driven until both the first piston 50 and the second piston 60 rise to their highest position as shown in Figure 35, when both the first piston 50 and the second piston 60 are at their lowest position as shown in Figure 33, is defined as the "reference drive time". The reference drive time can also be defined as the time required from when the pump 22 starts to be driven until the engagement protrusion 71 of the rotor 70 moves to the position shown by the dashed line, when the engagement protrusion 71 of the rotor 70 is positioned at the position shown by the solid line as shown in Figure 32.

In the second embodiment, the first drive time Ton1 is set longer than the reference drive time, and the second drive time Ton2 is set shorter than the reference drive time. Therefore, as shown in FIG. 32, when the drive time of the pump 22 is set to the first drive time Ton1, the engagement protrusion 71 of the rotor 70 contacts the second connection surface 447 of the fourth case 44 while the pump 22 is driven. In contrast, as shown in FIG. 40, when the drive time of the pump 22 is set to the second drive time Ton2, the engagement protrusion 71 of the rotor 70 does not contact the second connection surface 447 of the fourth case 44 while the pump 22 is driven.

However, if the second drive time Ton2 is too short, the drive of the pump 22 may be stopped before the first cam surface 74 of the engagement protrusion 71 of the rotor 70 faces the first guide surface 434 of the third case 43 in FIG. 40. In this case, the engagement protrusion 71 of the rotor 70 cannot move from the position shown by the solid line to the position shown by the two-dot chain line, and the engagement protrusion 71 of the rotor 70 returns to the position shown by the solid line. In other words, the same expansion and contraction of the air bag 21 is repeated. Therefore, it is preferable that the second drive time Ton2 is set to be equal to or longer than the time required for the first cam surface 74 of the engagement protrusion 71 of the rotor 70 to start facing the first guide surface 434 of the third case 43 after the drive of the pump 22 is stopped under the condition that the engagement protrusion 71 of the rotor 70 is positioned at the position shown by the dashed line. For the same reason, it is preferable that the stop time Toff is also set.

The effects of the second embodiment will be described.
(8) The rotary valve 30A can change the amount of air supplied to the air bag 21 by adjusting the drive time of the pump 22. That is, the rotary valve 30A can adjust the internal pressure of the air bag 21 by adjusting the drive time of the pump 22. In other words, the rotary valve 30A can change the intensity of the massage for the occupant by adjusting the drive time of the pump 22.

(9) By stopping the operation of the pump 22, the rotary valve 30A can lower the first piston 50 and the second piston 60, thereby discharging air from the air bag 21 to which the air was being supplied. In other words, the rotary valve 30A can stably switch between a state in which air is supplied to the air bag 21 and a state in which air is discharged from the air bag 21.

The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.
A rotary valve 30X according to a modified example of the first embodiment will be described with reference to Figures 41 to 44. The rotary valve 30X according to the modified example differs from the above embodiment in that the number of channels is set to "4" by changing the shape of the fifth case 45X. In the following description, the same reference numerals are used for configurations common to the above embodiment, and description thereof will be omitted or simplified.

As shown in FIG. 41, the rotary valve 30X includes a case 40X having a first case 41, a second case 42, a third case 43, a fourth case 44, and a fifth case 45X. Although not shown, the rotary valve 30X also includes a first piston 50, a second piston 60, a rotor 70, a switching unit 80, a first biasing member 91, a second biasing member 92, and a plurality of seal rings 101-105. In other words, the rotary valve 30X according to the second embodiment differs from the rotary valve 30 according to the first embodiment only in the configuration of the "fifth case."

As shown in Figures 42 and 43, the fifth case 45X is generally cylindrical. As shown in Figures 44 and 45, the fifth case 45X has a plurality of connection joints 451 (451a to 451d). The fifth case 45X also has a plurality of connection ports 452 (452a to 452h) that open to the bottom surface of the fifth case 45X, and a plurality of connection paths 454 (454a to 454d) whose one ends open to the plurality of connection joints 451 and whose other ends connect to the plurality of connection ports 452. The number of connection joints 451 and the number of connection paths 454 are equal to the number of channels of the rotary valve 30X, and the number of connection ports 452 is twice the number of channels of the rotary valve 30X.

When the fifth case 45X is viewed from the axial direction, the connection ports 452a and 452e are formed at positions on either side of the axis passing through the center of the fifth case 45X. The connection ports 452b and 452f are formed at positions on either side of the axis passing through the center of the fifth case 45X. The connection ports 452c and 452g are formed at positions on either side of the axis passing through the center of the fifth case 45X. The connection ports 452d and 452h are formed at positions on either side of the axis passing through the center of the fifth case 45X. The axis passing through the center of the fifth case 45X coincides with the rotation axis of the switching unit 80.

As shown in FIG. 45, the multiple connection paths 454 are formed with radially extending portions offset in the axial direction so that the connection paths 454 do not interfere with each other. The multiple connection paths 454 each branch off inside the fifth case 45X. In more detail, as shown in FIG. 44, the connection path 454a connects to the connection port 452a and the connection port 452e, the connection path 454b connects to the connection port 452b and the connection port 452f, the connection path 454c connects to the connection port 452c and the connection port 452g, and the connection path 454d connects to the connection port 452d and the connection port 452h.

The rotary valve 30X according to the modified example switches the air supply state to the multiple air bags 21 during one rotation of the switching unit 80 as follows. That is, the switching unit 80 switches from a first air supply state in which air is supplied to the air bag 21a via the connection port 452a to a first exhaust state in which air is exhausted from the air bag 21a via the connection port 452a.

Then, the switching unit 80 switches to a second air supply state in which air is supplied to the air bag 21b via the connection port 452b, and then switches to a second exhaust state in which air is exhausted from the air bag 21b via the connection port 452b.

Then, the switching unit 80 switches to a third air supply state in which air is supplied to the air bag 21c via the connection port 452c, and then switches to a third exhaust state in which air is exhausted from the air bag 21c via the connection port 452c.

Next, the switching unit 80 switches to a fourth air supply state in which air is supplied to the air bag 21d via the connection port 452d, and then sequentially switches to a fourth exhaust state in which air is exhausted from the air bag 21d via the connection port 452d.

Then, the switching unit 80 switches to a fifth air supply state in which air is supplied to the air bag 21a via the connection port 452e, and then switches to a fifth exhaust state in which air is exhausted from the air bag 21a via the connection port 452e.

Then, the switching unit 80 switches to a sixth air supply state in which air is supplied to the air bag 21b via the connection port 452f, and then switches to a sixth exhaust state in which air is exhausted from the air bag 21b via the connection port 452f.

Then, the switching unit 80 switches to a seventh air supply state in which air is supplied to the air bag 21c via the connection port 452g, and then switches to a seventh exhaust state in which air is exhausted from the air bag 21c via the connection port 452g.

Then, the switching unit 80 switches to the eighth air supply state in which air is supplied to the air bag 21d via the connection port 452h, and then switches to the eighth exhaust state in which air is exhausted from the air bag 21d via the connection port 452h. In this way, the switching unit 80 switches between the "16" air supply state and exhaust state during one rotation.

Furthermore, in this modified example, when connection port 452a is regarded as the "first connection port", connection port 452e corresponds to the "second connection port", and when connection port 452b is regarded as the "first connection port", connection port 452f corresponds to the "second connection port". When connection port 452c is regarded as the "first connection port", connection port 452g corresponds to the "second connection port", and when connection port 452d is regarded as the "first connection port", connection port 452h corresponds to the "second connection port".

The rotary valve 30X according to the modified example can inflate and deflate the four air bladders 21a to 21d twice while the switching unit 80 makes one rotation.
In the first and second embodiments, the number of channels of the rotary valves 30, 30A can be changed as appropriate. In this case, as shown in the modified example, the number of channels can be changed by changing only the fifth case 45 of the case 40, or the number of channels can be changed by changing the shapes of the components of the rotary valves 30, 30A. In addition, the number of channels of the rotary valves 30, 30A may be an even number or an odd number.

- In the first embodiment, the direction in which the valve body 82 of the switching unit 80 is displaced between the closed position and the open position does not have to be the radial direction. For example, the direction in which the valve body 82 of the switching unit 80 is displaced between the closed position and the open position may be the axial direction. In this case, it is preferable that the first exhaust passage 88 extends in the axial direction.

- In the third case 43 and the fourth case 44 according to the first and second embodiments, the gradient and length of the first guide surface 434 and the second guide surface 445 may be changed as appropriate. In addition, the gradient and length of the first guide surface 434 and the second guide surface 445, which are multiplexed in the circumferential direction, may be changed individually.

- In the first and second embodiments, the gradient of the first inclined surface 463 and the second inclined surface 464 of the restricting wall 461 of the fourth case 44 of the rotary valve 30, 30A may be changed as appropriate.

The communication passage 52 does not have to be formed in the first piston 50. The communication passage 52 may be formed in the first case 41 and the second case 42 as long as it connects the first air chamber AC1 and the second air chamber AC2.

- In the first and second embodiments, the communication passage 52 of the first piston 50 may be a flow passage having a so-called labyrinth structure, so long as it is possible to limit the flow rate of air supplied from the first air chamber AC1 to the second air chamber AC2.

- In the second embodiment, the first drive time Ton1 and the second drive time Ton2 may both be shorter than the reference drive time, or the first drive time Ton1 and the second drive time Ton2 may both be longer than the reference drive time.

- The first drive time Ton1 and the second drive time Ton2 may be constant. In this case, it is preferable to increase the discharge volume of the pump 22 when massaging the occupant strongly, and to decrease the discharge volume of the pump 22 when massaging the occupant weakly. In this respect, it can be said that the amount of air supplied to the air bag 21 is changed when changing the intensity of the massage.

In the first and second embodiments, the gas supplied to the air bag 21 may be a gas other than air.
In the first and second embodiments, the massage system 20 may be installed in a device other than the vehicle seat 10. For example, the massage system 20 may be installed in a massage machine used for home or commercial purposes.

The technical ideas that can be understood from the above-described embodiment and modified examples will be described.
The rotary valve is a rotary valve that switches between air bags to be inflated and deflated in sequence by switching the mode of air supply to a first air bag and a second air bag, and includes a case having a first air chamber to which air is supplied from an external space, a second air chamber connected to the first air chamber via a communication passage, a second exhaust port through which air discharged from the second air chamber passes, a first connection port through which air moving between the second air chamber and the first air bag passes, and a second connection port through which air moving between the second air chamber and the second air bag passes, and a case that partitions the first air chamber and the second air chamber, and is displaced between a closed position that closes the second exhaust port and an open position that opens the second exhaust port according to a pressure difference between the first air chamber and the second air chamber. the piston includes a biasing member biasing the piston in a direction decreasing the volume of the first air chamber; and a switching unit housed in the case and rotating while maintaining one of the first and second connection ports in an open state and the other in a closed state when the pressure of the second air chamber increases, and rotating so that the first and second connection ports that are in an open state become closed and the closed connection port becomes open when the pressure of the second air chamber decreases, wherein the direction in which the piston is displaced from the open position to the closed position is a direction in which the volume of the first air chamber increases and a direction in which the volume of the second air chamber decreases, and the communicating passage limits the flow rate of air between the first and second air chambers.

In the rotary valve of the above configuration, when air is supplied to the first air chamber, the flow rate of air supplied from the first air chamber to the second air chamber is limited by the communication passage to be less than the flow rate of air supplied from the external space to the first air chamber. As a result, a pressure difference occurs between the first air chamber and the second air chamber, and the piston displaces from the open position to the closed position against the biasing force of the biasing member. When the piston is in the closed position, the piston closes the second exhaust port, and the air supplied from the first air chamber to the second air chamber is no longer discharged to the external space. Therefore, the air supplied from the first air chamber to the second air chamber is supplied to the first air bag, and the first air bag expands. In addition, the pressure in the second air chamber increases, causing the switching unit to rotate. At this time, the switching unit maintains the open state of the first connection port, in other words, maintains the supply of air to the first air bag.

After that, when the supply of air to the first air chamber is stopped, the pressure difference between the first air chamber and the second air chamber is eliminated. Therefore, based on the biasing force of the biasing member, the piston is displaced from a closed position where the second connection port is closed to an open position where the second connection port is opened. Then, the second air chamber is connected to the outside space via the second connection port, and air is discharged from the first air bag. In addition, the pressure in the second air chamber decreases, causing the switching unit to rotate. At this time, the switching unit closes the first connection port and opens the second connection port. Therefore, when the supply of air to the first air chamber is resumed, the second air chamber expands, and when the supply of air to the first air chamber is stopped, the second air chamber contracts.

In this way, when the supply of air to the first air chamber is stopped, the rotary valve exhausts air from the air bag to which the air is to be supplied. This allows the rotary valve to stably switch between a state in which air is supplied to the air bag and a state in which air is exhausted from the air bag. Furthermore, the rotary valve can continue to supply air to the same air bag as long as the supply of air to the first air chamber continues. Therefore, the rotary valve can adjust the internal pressure of the air bag depending on the time that air is supplied to the first air chamber.

21 (21a to 21h)...Air bag 30, 30X...Rotary valve 40, 40X...Case 425...Second exhaust port 452 (452a to 452h)...Connection port 453 (453a to 453h)...Connection path 461...Restriction wall 463...First inclined surface 464...Second inclined surface 465...Recess 50...First piston (piston)
52: communication passage 60: second piston 80: switching portion 82: valve body 88: first exhaust port (exhaust port)
91...First biasing member (biasing member)
92: Second biasing member AC1: First air chamber AC2: Second air chamber (air chamber)

Claims (5)

A rotary valve for inflating and deflating an air bag by switching an air supply mode to the air bag,
a case having a first air chamber to which air is supplied from an external space, a second air chamber connected to the first air chamber via a communication passage, a first exhaust port and a second exhaust port through which air exhausted from the second air chamber passes, and a connection port through which air moving between the second air chamber and the air bag passes;
a piston that divides the first air chamber and the second air chamber, and that displaces between a closed position that closes the second exhaust port and an open position that opens the second exhaust port in response to a pressure difference between the first air chamber and the second air chamber;
a switching unit that is housed in the case and rotates when a pressure in the second air chamber increases or decreases, thereby switching a connection state between the second air chamber and the external space via the first exhaust port,
a direction in which the piston is displaced from the open position to the closed position is a direction in which the volume of the first air chamber is increased and a direction in which the volume of the second air chamber is decreased,
The communication passage limits the flow rate of air supplied from the first air chamber to the second air chamber under a condition in which air is supplied from the external space to the first air chamber. The rotary valve according to claim 1 , wherein the communication passage is formed in the piston. The rotary valve according to claim 1 or 2, further comprising a biasing member that biases the piston in a direction in which the volume of the first air chamber decreases. The air bag includes a first air bag and a second air bag,
the connection port includes a first connection port through which air moving between the second air chamber and the first air bag passes, and a second connection port through which air moving between the second air chamber and the second air bag passes,
When the case is viewed from an axial direction of the switching unit, the first connection port and the second connection port are formed at positions sandwiching a rotation axis of the switching unit,
During one rotation of the switching unit,
a first air supply state in which air is supplied to the first air bag through the first connection port;
a first exhaust state in which air is exhausted from the first air bag through the first connection port;
a second air supply state in which air is supplied to the second air bag through the second connection port;
The rotary valve according to any one of claims 1 to 3, wherein the rotary valve is configured to sequentially switch between a first exhaust state, a second exhaust state, and a second exhaust state in which air is exhausted from the second air bag via the second connection port. the connection port includes a first connection port through which air moving between the second air chamber and the air bag passes, and a second connection port through which air moving between the second air chamber and the air bag passes,
When the case is viewed from an axial direction of the switching unit, the first connection port and the second connection port are formed at positions sandwiching a rotation axis of the switching unit,
During one rotation of the switching unit,
a first air supply state in which air is supplied to the air bag through the first connection port;
a first exhaust state in which air is exhausted from the air bag through the first connection port;
a second air supply state in which air is supplied to the air bag through the second connection port;
The rotary valve according to any one of claims 1 to 3, wherein the rotary valve is configured to sequentially switch between a first exhaust state, a second exhaust state, and a second exhaust state in which air is exhausted from the air bag via the second connection port.