Airbag module

Abstract

This airbag module comprises: an airbag having a gas introduction port; a module case which has a gas supply port connected to the gas introduction port of the airbag and in which an accommodation space accommodating internal gas is formed; a gas generator which is attached to the module case and supplies gas generated upon activation into the accommodation space of the module case; and a pusher which is disposed so as to be movable in the accommodation space by the pressure of the gas supplied from the gas generator due to activation of the gas generator, and which pushes, due to movement accompanying the activation of the gas generator, the internal gas that had been accommodated in the accommodation space even before the activation of the gas generator to the airbag.

Description

Airbag module

[0001] The present invention relates to an airbag module.

[0002] In recent years, vehicles have been equipped with airbag devices (airbag modules) that deploy airbags to protect occupants in the event of a collision. Airbag devices for vehicles have been proposed to be installed in the steering wheel, on the sides of seats, near windows on the roof, and so on.

[0003] Patent Document 1 proposes an airbag assembly including an airbag cushion, an inflator, and a plurality of high-velocity nozzles coupled to the inflator and configured to deliver inflation gas from the inflator to the airbag cushion, wherein the housing of the airbag assembly includes an intake port configured to allow ambient air to be drawn into the airbag cushion during inflation of the airbag cushion.

[0004] U.S. Pat. No. 10,124,759

[0005] In the above-described airbag assembly, the gas ejected from the inflator enters the bag while drawing in surrounding air, but there is a problem in that the gas is not used efficiently when the inflator is activated.

[0006] The technology disclosed herein has been made in consideration of the above-mentioned circumstances, and its purpose is to provide a technology for efficiently deploying an airbag by utilizing gas generated when a gas generator is activated to introduce gas that has been stored in the module prior to activation into the airbag.

[0007] In order to solve the above problems, the technology of the present disclosure employs the following configuration: That is, the airbag module of the present disclosure includes: an airbag having a gas inlet, a module case having a gas supply port connected to the gas inlet of the airbag and having an accommodating space formed therein for accommodating internal gas, a gas generator attached to the module case and supplying gas generated upon activation into the accommodating space of the module case, and a pusher disposed so as to be movable within the accommodating space by the pressure of gas supplied from the gas generator upon activation of the gas generator, and pushing out the internal gas that had been accommodated in the accommodating space before activation of the gas generator into the airbag as it moves in conjunction with the activation of the gas generator.

[0008] The module case may have an air inlet hole for introducing air from outside the module case, and a check valve may be attached to the air inlet hole for preventing gas inside the module case from leaking to the outside.

[0009] The plunger may include a moving body arranged at the tip end in the direction of movement, and an expanding tube which is a bellows-shaped tube or a nested multi-tube body connected to the moving body and expands so as to extend in one direction due to the gas generated from the gas generator, and the expanding tube may extend when the gas generator is activated, thereby moving the moving body from a start position to a terminal position within the accommodation space.

[0010] The outside air introduction hole may be formed closer to the start position than the end position in the module case.

[0011] The plunger may have a communication hole that connects the air passage in the expanding tube, to which gas is supplied from the gas generator, with the gas supply port of the module case, and the gas may be supplied to the gas supply port side of the module case through the communication hole.

[0012] The module case may include: an accommodation portion that defines the accommodation space and accommodates the plunger; and a communication path that connects the accommodation space and the gas supply port and serves as a passage for gas supplied from the accommodation space.

[0013] The module case may include: a storage section that defines the storage space and stores the plunger; and a communication path that connects the storage space to the gas supply port and serves as a passage for the internal gas stored in the storage space, the outside air introduced from outside the module case, and the gas supplied from the gas generator via an air passage in the expanding tube.

[0014] In the airbag module, the gas generator is a pyrotechnic gas generator that generates the gas by burning at least a gas generating agent, the cross-sectional shape of the moving body in a cross section perpendicular to the direction of movement is the same as the cross-sectional shape of the storage space in the same cross section, and when moving, the outer peripheral surface of the moving body is fitted into the storage section so as to slide along the inner peripheral surface of the storage section, the storage space is divided into a first space that is closer to the communication path than the moving body and a second space that is closer to the gas generator than the moving body, and a communication hole that connects the second space to the communication path is closed to prevent communication between the second space and the communication path at least from the time the tip of the pusher starts to move due to activation of the gas generator until it reaches an intermediate position where the volume of the first space is smaller than the volume of the second space, and when the tip of the pusher passes the intermediate position, the communication hole is opened to connect the second space to the communication path.

[0015] According to the present disclosure, a technology can be provided in which gas stored in the module prior to activation is introduced into the airbag by utilizing the gas generated when the gas generator is activated, thereby efficiently deploying the airbag.

[0016] FIG. 1 is a schematic diagram of an airbag module according to a first embodiment. FIG. 2 is a right side view of the airbag module. FIG. 3 is a schematic cross-sectional view showing the state of the airbag module when activated. FIG. 4 is a view showing the state in which the airbag is deployed. FIG. 5 is a schematic diagram of an airbag module according to a second embodiment. FIG. 6 is a schematic diagram of an airbag module according to a third embodiment. FIG. 7 is a schematic diagram of an airbag module according to a fourth embodiment, showing the state before activation. FIG. 8 is a schematic diagram of the airbag module according to the fourth embodiment, showing the state when activated.

[0017] Hereinafter, a gas generator according to an embodiment of the present disclosure will be described with reference to the drawings. Note that each configuration and combination thereof in each embodiment is an example, and addition, omission, substitution, and other modifications of configurations are possible as appropriate within the scope of the gist of the present invention. The present invention is not limited to the embodiments, but is limited only by the claims.

[0018] First Embodiment FIG. 1 is a schematic diagram of an airbag module 1 according to this embodiment. The airbag module 1 is installed, for example, inside a vehicle and deploys an airbag 20 to protect an occupant during a vehicle collision. However, the airbag module 1 may also be installed outside the vehicle (e.g., around the hood) or inside the hood to protect a pedestrian. The airbag module 1 may also be installed on a bicycle, a motorcycle, or a recreational vehicle (such as a roller coaster or a go-kart) or on a driver or passenger thereof. Furthermore, the airbag module 1 may be installed on a pedestrian. FIG. 1 illustrates an example of a passenger airbag device mounted on the dashboard of a vehicle. FIG. 1 also illustrates a state before the airbag 20 is deployed, i.e., before the airbag module 1 is activated due to a collision or the like.

[0019] Fig. 2 is a right side view of the airbag module 1, Fig. 3 is a schematic cross-sectional view showing the state of the airbag module 1 when activated, and Fig. 4 is a view showing the state in which the airbag is deployed. In Figs. 1 to 4, the up-down direction is designated as the Y direction, the left-right direction as the X direction, and the front-rear direction as the Z direction. These directions are shown as examples for the sake of convenience, and the configuration of the airbag module 1 is not limited to these. For example, the direction in which the airbag module 1 is arranged is not limited to the direction shown in the figure. The same applies to the subsequent drawings.

[0020] The airbag module 1 is embedded in the dashboard located in front of the passenger seat. The airbag module 1 includes a gas generator 10 that generates gas when activated, an airbag 20 that deploys upon receiving the gas, a module case 30, and a plunger 40.

[0021] The module case 30 includes a base 31 that holds the gas generator 10, the airbag 20, and the plunger 40, and a cover member 32 that is attached to the vehicle interior side (occupant side) of the base 31. The base 31 has a gas supply port 311 connected to the gas inlet 21 of the airbag 20, and an accommodation space 312 that communicates with the gas supply port 311 and accommodates the internal gas is formed inside. The space between the gas inlet 21 and the gas supply port 311 may be covered with a rupturable blocking member, a perforated plate, or the like before activation.

[0022] Module case 30 defines accommodation space 312, has accommodation section 313 that accommodates plunger 40, and connects accommodation space 312 to gas supply port 311. Module case 30 also has communication path 33 that serves as a passage for internal gas accommodated in accommodation space 312, outside air introduced from outside the module case, and gas supplied from gas generator 10. Accommodation section 313 has a cylindrical peripheral wall 315 that surrounds accommodation space 312, and has a right side wall 316 at one end and a left side wall 317 at the other end. A gas introduction hole 318 is formed in right side wall 316.

[0023] Furthermore, module case 30 has an outside air inlet hole 319 in right side wall 316 that introduces outside air from outside the module case, and outside air inlet hole 319 is fitted with a check valve 314 that prevents gas within the module case from leaking to the outside. Check valve 314 is, for example, a swing-type chuck valve whose valve element swings inwardly toward module case 30. In this case, when the inside of module case 30 is at negative pressure, outside air is allowed to pass into the module case, and when the inside is at positive pressure, the valve element closes to prevent gas within the module case from leaking to the outside. Note that the gas within the module case includes gas present within the module case before activation, as well as outside air introduced from outside air inlet hole 319 during activation and gas supplied from gas generator 10.

[0024] Pusher 40 includes movable body 41 disposed at the tip side in the direction of movement, and expanding tube 42 connected to movable body 41. Expanding tube 42 is a nested multi-cylinder body, and the end opposite to movable body 41 is connected to gas introduction hole 318 in right side wall 316, and expands so as to extend in one direction when generated gas from gas generator 10 is supplied into the expanding tube. In this way, expanding tube 42 extends when gas generator 10 is activated, and pusher 40 moves movable body 41 from start position 41A to end position 41B within the accommodation space. Note that, in the present embodiment, expanding tube 42 is a nested multi-cylinder body, but the configuration is not limited to this, and expanding tube 42 may be a bellows-shaped cylinder that expands when supplied with gas from gas generator 10.

[0025] The cross-sectional shape of the movable body 41 in a cross section perpendicular to the movement direction (X direction) is substantially the same as the cross-sectional shape of the accommodation space 312 in the same cross section. In other words, the shape of the movable body 41 is such that it fits exactly inside the accommodation portion. Note that the cross-sectional shapes of the movable body 41 and the accommodation space 312 do not need to be exactly the same, and the movable body 41 may be smaller than the accommodation space 312, so that the movable body 41 is a clearance fit. Furthermore, if the movable body 41 has elasticity and is fitted into the accommodation portion in a compressed state, the movable body 41 before compression may be formed larger than the accommodation space.

[0026] The movable body 41 is fitted into the accommodating section 313 so that its outer surface slides along the inner surface of the accommodating section 313 when it moves, dividing the accommodating space 312 into a first space 411 on the communication path side of the movable body 41 and a second space 412 on the gas generator side of the movable body 41.

[0027] The inner space of the extension tube 42 serves as an air passage 421 for gas supplied from the gas generator 10, and a communication hole 422 is provided near the tip of the extension tube 42 (near the moving body 41 when the extension tube 42 is in an extended state) to connect the air passage 421 to the connecting passage 33.

[0028] The cover member 32 is attached to the base body 31 so as to cover the airbag 20 held by the base body 31. In other words, by attaching the cover member 32 to the base body 31, an accommodation space 32A is formed inside the module case 30 formed by the base body 31 and the cover member 32, and the airbag 20 is accommodated in this accommodation space 32A. The cover member 32 is made of synthetic resin or the like, and is provided with a tear line at a predetermined position that is formed to be weaker than other portions.

[0029] The gas generator 10 is, for example, a pyrotechnic gas generator that generates gas by burning a gas generating agent. The gas generator 10 of the present embodiment may be one that generates at least combustion gas, and may be a hybrid gas generator that uses combustion gas and compressed air. Furthermore, the gas generator 10 is not limited to this, and may be a type that releases compressed air without generating combustion gas.

[0030] Gas generator 10 is connected to control unit 50 and is operated under the control of control unit 50. For example, when an operating current (ignition current) is supplied from control unit 50, gunpowder in the gas generator is ignited, and combustion gas is generated by the combustion of the gunpowder. As a result, the combustion gas is introduced from gas discharge hole 11 of gas generator 10 into gas introduction hole 318 of module case 30.

[0031] The airbag 20 is housed in a folded state inside the module case. When the airbag 20 receives gas from the gas generator 10, it inflates, rupturing the cover member 32 of the module case 30 and deploying to the front side of the airbag module 1.

[0032] The control unit 50 is connected to a sensor 60, which detects the state of the vehicle or the state of the surroundings of the vehicle. Based on the detection results, the control unit 50 determines whether or not to activate the airbag module 1, and if so, supplies an ignition current to the airbag module 1.

[0033] The sensor 60 is, for example, an impact sensor for detecting a vehicle collision. The sensor 60 is not limited to a sensor for detecting impacts, but may also be a sensor for detecting information about the surroundings of the vehicle in order to predict a collision. For example, the sensor 60 may include sensing means such as an acceleration sensor, a gyro sensor (angular velocity sensor), a positioning device, a camera, radar, LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging), or a three-dimensional scanner. Examples of the positioning device include satellite positioning systems such as the Global Positioning System (GPS). The radar and LIDAR determine the distance to objects around the vehicle and the movement speed of the objects. When the airbag module 1 is mounted on an object other than a vehicle, such as a person or a bicycle, the sensor 60 detects the state of the object, such as the person or bicycle.

[0034] The control unit 50 acquires the detection result from the sensor 60, and when the detection result satisfies a predetermined condition, supplies an ignition current to the gas generator 10, thereby activating the gas generator 10 and starting the supply of combustion gas. The gas supplied from the gas generator 10 is introduced into the expanding tube through the gas inlet 318. Here, as shown in FIG. 1 , in the expanding tube 42 before deployment, the individual tubes overlap each other, and the communication hole 422 is blocked by the tube located on the outside. When the internal pressure of the air passage 421 increases with the introduction of the combustion gas, the expanding tube 42 expands, and the moving body 41 is moved from the start position 41A to the end position 41B. When the moving body 41 moves in this manner, the internal gas contained in the first space 411 on the communication passage 33 side of the start position 41A is pushed out by the moving body 41 into the communication passage 33 and supplied into the airbag 20 through the gas supply port 311. In addition, an outside air inlet hole 319 is formed closer to the starting position 41A than the terminal position 41B of the module case 30 (in this embodiment, the right side wall 316). When the moving body 41 moves, the second space 412 expands and becomes negative pressure, and outside air is introduced through the outside air inlet hole 319.

[0035] 3, when the plunger 40 is extended, the communication hole 422 provided near the tip of the extension tube 42 opens, and the combustion gas ejected from the communication hole 422 is supplied to the communication path 33. At this time, the combustion gas ejected from the communication hole 422 entrains the outside air introduced into the second space 412 and is supplied to the communication path 33. Therefore, the outside air is supplied to the airbag 20 together with the combustion gas through the communication path 33, deploying the airbag 20 and activating the airbag module 1.

[0036] In this manner, in this embodiment, not only the gas supplied from the gas generator 10 but also the internal gas contained in the module case before activation and the outside air introduced from the outside air inlet hole 319 are supplied to the airbag 20, allowing the airbag 20 to be deployed efficiently.

[0037] In general, devices that inflate an airbag by drawing in air along with gas from a gas generator not only supply gas closer to atmospheric components to the airbag, but also allow for a smaller, lighter gas generator due to the reduced amount of gas supplied from the gas generator. However, the airbag module of this embodiment is even more effective in terms of thermal effects. In other words, in the airbag module 1 of this embodiment, the internal gas contained within the module case is first supplied to the airbag 20 before activation, preventing damage to the airbag 20 due to the heat of the combustion gas even when a pyrotechnic gas generator 10 is used. Furthermore, in the airbag module 1 of this embodiment, the combustion gas is supplied while incorporating outside air, lowering the temperature of the combustion gas, thereby minimizing damage to the airbag 20 due to the heat of the combustion gas and improving reliability.

[0038] Furthermore, in the airbag module 1 of the present embodiment, the communication hole 422 is closed when the moving body 41 is located at the start position 41A, and the communication hole 422 is opened after the moving body 41 moves toward the terminal position 41B, thereby connecting the second space 412 and the communication path 33. This allows outside air to be introduced appropriately. Note that communication between the second space 412 and the communication path 33 does not necessarily occur when the moving body 41 reaches the terminal position 41B. A configuration may be adopted in which the communication between the second space 412 and the communication path 33 is not established at least from the time the moving body 41 starts moving due to activation of the gas generator 10 until the moving body 41 reaches an intermediate position where the volume of the first space 411 is smaller than the volume of the second space 412, and the communication is established when the moving body 41 passes the intermediate position. Alternatively, a cover such as sealing tape or a sheet material may be provided to close the communication hole 422, and the cover may be removed at a predetermined timing by the heat or pressure of the combustion gas, opening the communication hole 422 and connecting the air passage 421 and the communication path 33.

[0039] 5 is a schematic diagram of an airbag module 1A according to a second embodiment. This embodiment differs from the previous embodiment in that the communication holes are formed in a nozzle shape, but the other configurations are the same. Therefore, the same elements are denoted by the same reference numerals, and a repeated description will be omitted.

[0040] As shown in FIG. 5 , in this embodiment, an upward-facing nozzle 423 is provided near the tip of the spreading tube 42, and a tip opening 424 of the nozzle 423 communicates with the air passage 421 inside the spreading tube 42. In this embodiment, the tip opening 424 of the nozzle 423 functions as a communication hole. Note that the tip of the nozzle 423 contacts the inner circumferential surface of the storage section 313 when the tip is closer to the start position than the terminal position 41B, thereby closing the tip opening 424. When the movable body 41 moves to the terminal position 41B and the nozzle 423 reaches the opening 31A on the storage section side of the communication passage 33, the tip opening 424 opens, and the air passage 421 and the communication passage 33 communicate with each other. Furthermore, a configuration can be adopted in which the tip opening 424 is closed with a blocking member, and when the tip of the nozzle 423 is closer to the start position than the terminal position 41B, the inner circumferential surface of the storage section 313 prevents the blocking member from tearing open. In this manner, in this embodiment, the tip opening 424 of the nozzle 423 is disposed close to the communication passage 33, and combustion gas can be efficiently supplied to the communication passage 33. Also, in this embodiment, the tip opening 424 of the nozzle 423 is closed when it comes into contact with the inner surface of the storage section, and is opened when it reaches the opening 31A of the communication passage 33, so that the ventilation passage 421 and the communication passage 33 communicate with each other at an appropriate timing, and outside air can be efficiently introduced.

[0041] 6 is a schematic diagram of an airbag module 1B according to a third embodiment. This embodiment differs from the second embodiment in that the communication holes are formed on the side surfaces of the vehicle body, but the other configurations are the same. Therefore, the same elements are denoted by the same reference numerals, and a repeated description will be omitted.

[0042] As shown in FIG. 6 , in this embodiment, a communication hole 414 is provided on the upper surface of the movable body 41, and the communication hole 414 communicates with the ventilation passage 421 inside the expanding tube 42. The communication hole 414 is closed by contacting the inner circumferential surface of the housing portion 313 closer to the starting position than the terminal position 41B. When the movable body 41 moves to the terminal position 41B and the communication hole 414 reaches the opening 31A of the communication passage 33 on the housing portion side, the communication hole 414 opens, and the ventilation passage 421 and the communication passage 33 communicate with each other. In this embodiment, the communication hole 414 is positioned close to the communication passage 33, allowing efficient supply of combustion gas to the communication passage 33. Furthermore, in this embodiment, the communication hole 414 is closed by contact with the inner surface of the housing portion and opens when it reaches the opening 31A of the communication passage 33. This allows the ventilation passage 421 and the communication passage 33 to communicate with each other at the appropriate time, allowing efficient introduction of outside air.

[0043] <Fourth embodiment> Fig. 7 is a schematic diagram showing the state before activation of an airbag module 1C according to a fourth embodiment, and Fig. 8 is a schematic diagram showing the state during activation of the airbag module 1C according to the fourth embodiment. This embodiment differs from the third embodiment in that the expanding tube 42 is omitted, but the other configurations are the same. For this reason, the same elements are designated by the same reference numerals, and repeated description will be omitted.

[0044] 7 , in this embodiment, the plunger 40 does not include an extension tube 42, and instead has a communication hole 414 on the upper surface of the movable body 41, which communicates with the second space 412. Furthermore, an outside air introduction path 39 connected to the outside air introduction hole 319 is formed in the second space 412, and a choke portion 391 is provided at the tip of the outside air introduction path 39, with an opening 392 narrowed by the choke portion 391 facing the combustion gas path. The opening 392 is formed by extending a cylinder separating the outside air introduction path 39 from the second space 412 from the right side wall 316 toward the choke portion 391, between the tip of the opening 392 and the choke portion 391.

[0045] When combustion gas is supplied from the gas generator 10 via the gas introduction hole 318 and the pressure in the second space 412 increases, the moving body 41 moves from the start position 41A toward the terminal position 41B, as shown in FIG. 8 . The communication hole 414 is closed by coming into contact with the inner circumferential surface of the housing portion 313 on the start position side of the terminal position 41B. When the moving body 41 moves to the terminal position 41B and reaches the opening 31A on the housing side of the communication path 33, the communication hole 414 is opened, and the air passage 421 and the communication path 33 communicate with each other. Furthermore, when combustion gas is supplied from the gas generator 10, outside air is sucked through the opening 392 of the choke portion 391 and introduced into the second space 412. As a result, the outside air is supplied to the airbag 20 through the communication path 33 together with the combustion gas, and the airbag 20 can be efficiently deployed despite a simple configuration that does not include the expansion tube 42.

[0046] <Others> Preferred embodiments of the present disclosure have been described above, but each aspect disclosed in this specification can be combined with any other feature disclosed in this specification.

[0047] DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C: Airbag module 10: Gas generator 11: Gas discharge hole 20: Airbag 21: Gas inlet port 30: Module case 31: Base body 31A: Opening 32: Cover member 32A: Storage space 33: Communication path 39: Outside air introduction path 40: Push-in member 41: Moving body 41A: Start position 41B: End position 42: Extension tube 50: Control unit 60: Sensor 311: Gas supply port 312: Storage space 313: Storage section 314: Check valve 315: Peripheral wall 316: Right side wall 317: Left side wall 318: Gas introduction hole 319: Outside air introduction hole 391: Choke section 392: Opening 411 : First space 412 : Second space 414 : Communication hole 421 : Air passage 422 : Communication hole 423 : Nozzle 424 : Tip opening

Claims

1. An airbag module comprising: an airbag having a gas inlet; a modular case having a gas supply port connected to the gas inlet of the airbag and having an internal storage space formed therein for storing internal gas; a gas generator attached to the modular case for supplying gas generated upon activation into the storage space of the modular case; and a plunger disposed so as to be movable within the storage space by the pressure of gas supplied from the gas generator upon activation of the gas generator, and forcing the internal gas, which had been stored in the storage space before activation of the gas generator, into the airbag as it moves in conjunction with the activation of the gas generator.

2. An airbag module as described in claim 1, wherein the module case has an outside air inlet hole for introducing outside air from outside the module case, and the outside air inlet hole is fitted with a check valve for preventing gas inside the module case from leaking to the outside.

3. An airbag module as described in claim 1 or 2, wherein the plunger comprises: a moving body arranged at the tip end in the direction of movement; and an expanding tube which is a bellows-shaped tube or a nested multi-tube body connected to the moving body and which expands so as to extend in one direction due to the gas generated from the gas generator; and when the gas generator is activated, the expanding tube expands, thereby moving the moving body from a start position to a terminal position within the storage space.

4. An airbag module according to claim 3, which relies on claim 2, wherein the outside air introduction hole is formed closer to the start position than the end position in the module case.

5. An airbag module as described in claim 3, wherein the plunger has a communication hole that connects the air passage in the expanding tube, to which gas is supplied from the gas generator, with the gas supply port of the module case, and the gas is supplied to the gas supply port side of the module case through the communication hole.

6. An airbag module according to claim 3, wherein the module case includes: a storage section that defines the storage space and stores the plunger; and a communication path that connects the storage space with the gas supply port and serves as a passage for gas supplied from the storage space.

7. An airbag module as described in claim 3 which cites claim 2, wherein the module case includes: a storage section which defines the storage space and stores the plunger; and a communication path which connects the storage space with the gas supply port and serves as a passage for the internal gas stored in the storage space, the outside air introduced from outside the module case, and the gas supplied from the gas generator via the ventilation path in the expanding tube.

8. The airbag module according to claim 7, wherein the gas generator is a pyrotechnic gas generator that generates the gas by burning at least a gas generating agent, the movable body has a cross-sectional shape in a cross section perpendicular to the direction of movement that is the same as the cross-sectional shape of the storage space in the same cross section, the movable body is fitted into the storage section so that the outer peripheral surface of the movable body slides along the inner peripheral surface of the storage section during movement, the storage space is divided into a first space that is closer to the communication path than the movable body and a second space that is closer to the gas generator than the movable body, and the communication hole that communicates the second space with the communication path is closed to prevent communication between the second space and the communication path at least from the time the tip of the pusher starts to move due to activation of the gas generator until it reaches an intermediate position where the volume of the first space is smaller than the volume of the second space, and the communication hole is opened when the tip of the pusher passes the intermediate position to allow communication between the second space and the communication path.

Images