JPH0820099B2 - Ventilation equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a ventilation device for ventilating the interior of an automobile or a building, for example, and more specifically, exhausts dirty air in the interior (hereinafter referred to as “inside air”) to the outside. The present invention relates to the improvement of the inside air discharge device for achieving the above.

[Prior Art] A conventional ventilator has an internal air exhaust port for exhausting indoor air to the outside of the room as disclosed in, for example, Japanese Utility Model Publication No. 62-9130 and Japanese Patent Publication No. 59-63221. The body and the inside air discharge port are closed by closing the inside air discharge port as a valve seat except when the inside air is discharged outside the room. A one-way valve that opens the inside air discharge port only in the discharge direction is provided.

The one-way valve is formed in a plate shape slightly larger than the inside air discharge port and is arranged on the surface of the mouth frame outside the room. For example, the upper end of the one way valve is mounted immediately above the inside air discharge port. As a result, substantially the entire portion except the upper end portion is swingably provided around the mounting portion. The one-way valve closes the inside air discharge port by contacting the valve seat portion by its own weight except when the inside air is discharged to the outside of the room. (It is caused by the negative pressure generated on the surface and acts on the one-way valve.) When it becomes a size that overcomes its own weight, it will swing away from the valve seat to the outside and only in the direction to discharge the inside air to the outside. It is designed to open the inside air outlet.

This ventilator is used, for example, by mounting it on a car, but the inside air in a relatively small room of the car is easily contaminated by cigarette smoke, human breath, etc., so that it is required that the inside air be quickly discharged to the outside. Has been done. Therefore, conventionally, by reducing the thickness of the one-way valve to reduce its own weight, the inside air discharge port can be opened even with a small pressure difference, and the dirty inside air can be discharged efficiently. I am trying to do it.

[Problems to be Solved by the Invention] However, when the one-way valve is made thin to reduce its own weight as in the above-described conventional example, the contact force with respect to the valve seat portion when the one-way valve closes the inside air discharge port is reduced. Since the edge portion of the one-way valve is easily deformed as it becomes weaker, there is a drawback that a gap is generated between the one-way valve and the valve seat portion and the sealing property of the inside air discharge port is deteriorated. Further, the one-way valve, which has a small self-weight, is likely to jump up under the influence of vibration when the vehicle is running, for example, so that the inside air discharge port may be greatly opened. When the inside air discharge port deteriorates in sealing property or is unnecessarily opened in this way, dirty air outside the room (hereinafter referred to as outside air) containing dust, dust, smoke, odor, etc. enters the room from the inside air discharge port. Since it may flow backwards and cause discomfort to people,
It has been a pending issue from the past. In particular, this backflow phenomenon occurs remarkably when the vehicle is traveling in a place where dust is likely to fly up, and a ventilation device that can keep the inside air outlet securely closed by the user of the vehicle is provided. Many requests were made for it.

An object of the present invention is to solve the above-mentioned problems and to keep the inside air discharge port closed with a one-way valve securely except when the inside air is discharged to the outside of the room. It is an object of the present invention to provide a novel ventilation device capable of preventing backflow from the outlet into the room.

[Means for Solving the Problems] In order to achieve the above object, the ventilating apparatus of the present invention is different from an opening frame body having an inside air discharge port for discharging the inside air to the outside of the room and a case of discharging the inside air to the outside of the room. Is in contact with the peripheral portion of the inside air outlet serving as a valve seat portion to close the inside air outlet,
In the ventilator provided with a one-way valve that opens the inside air discharge port only in the discharge direction away from the valve seat portion due to the atmospheric pressure difference between the inside and the outside when discharging the inside air to the outside, At least the valve seat portion and the hanging member of the mouth frame are formed of resin containing magnetic powder, and at least the valve seat portion and the hanging portion of the one-way valve are provided. The contact portion for the transfer member is formed of rubber or elastomer containing magnetic powder, and at least one of the magnetic powder of the valve seat portion and the transfer member or the magnetic powder of the contact portion is magnetized. The permanent magnet powder is characterized in that the magnetic attraction force between the valve seat portion and the hanging member and the contact portion is ² to 10 g / cm ² . Here, "magnetic powder particles" is a concept that includes magnetically attractable powder particles and magnetized permanent magnet powder particles.

Here, the "mouth frame" is provided with at least the inside air discharge port and the peripheral portion thereof, and includes, for example, the following (1) to
A separate member may be added as in (4).

(1) A mounting member for integrally mounting the mouth frame to a mounting location of a ventilation device (for example, a vehicle body of an automobile), which is integrally formed with the mouth frame.

(2) The mounting member of (1) above is formed and added as a separate component from the mouth frame.

(3) An inside air introduction duct for taking in the inside air and introducing it to the inside air discharge port, or an inside air discharge duct for discharging the inside air discharged from the inside air discharge port to the outside of the room and the mouth frame body. The one that is integrally formed and added.

(4) The inside air introduction duct or the inside air discharge duct of (3) above is formed and added as a separate component from the mouth frame.

Further, the shape of the inside air discharge port of the mouth frame can be appropriately set to a quadrangle, a triangle, a circle, or the like as necessary. Similarly, the number of openings and the opening area of the inner airflow inlet can be appropriately set as necessary.

Next, the "hanging member" of the mouth frame is provided so as to be hung on the inside air discharge port, and the hang position and the number are not particularly limited, and the following (1) ~
(4) can be illustrated.

(1) One hanging member that traverses the inside air discharge port.

(2) Two or more hanging members that intersect at one point in the inside air outlet.

(3) Three or more hanging members that intersect at two or more points in the inside air outlet.

(4) Two or more hanging members that do not intersect in the inside air discharge port.

Next, in the "one-way valve", the contact portion is in contact with the valve seat portion and the suspension member of the mouth frame body to close the inside air discharge main opening except when the inside air is discharged to the outside of the room. However, when the inside air is discharged to the outside of the room, the inside air discharge port is opened only in the direction of discharging the inside air to the outside due to the pressure difference between the inside and the outside of the room. Therefore, firstly, the one-way valve is formed to be slightly larger than the inside air discharge port so as to come into contact with the valve seat portion of the mouth frame. Secondly, the one-way valve is disposed on the surface of the mouth frame body on the outdoor side, and, for example, the upper end of the one-way valve is attached immediately above the inside air discharge port, so that substantially the entire portion except the upper end is It is provided to be swingable around the mounting portion. The one-way valve swings in the direction to open the inside air outlet (outdoor side) due to the pressure difference between the inside and outside of the room, and swings in the direction to close the inside air outlet (inside air outlet side) by its own weight. It is supposed to do.

The main material of this one-way valve is rubber or elastomer (which means a rubber-like soft synthetic resin). The one-way valve, including its swing center, may be integrally formed of rubber or elastomer, and may be swung by utilizing its flexibility due to its elasticity. In this case, the swing resistance can be reduced by forming the portion that becomes the swing center to be thinner than the other portions.

Next, as an aspect of magnetically attracting the valve seat portion and the hanging member of the mouth frame body and the contact portion of the one-way valve,
There are the following combinations (1) to (3).

(1) Resin in which at least the valve seat portion (including a part thereof; the same applies hereinafter) and the hanging member (including a part thereof; the same applies below) of the mouth frame body contains a permanent magnet powder. And a part of the one-way valve (including a part of the one-way valve, the same applies hereinafter) is formed of rubber or elastomer containing a magnetic adsorptive powder.

(2) At least the valve seat portion and the bridging member of the mouth frame are made of a resin containing a magnetically attractable powder, and at least the contact portion of the one-way valve is a rubber containing a permanent magnet powder. An embodiment formed of an elastomer.

(3) At least the valve seat portion and the bridging member of the mouth frame are made of a resin containing a magnetically attractable powder, and at least the contact portion of the one-way valve is a rubber containing a permanent magnet powder. An embodiment formed of an elastomer.

Here, as the "permanent magnet powder granules", Alnico,
Alloys such as iron-chromium-cobalt, manganese-aluminum-carbon, hard ferrite (barium ferrite,
Examples thereof include metal oxides such as hard magnetic ferrites such as strontium ferrite) and intermetallic compounds such as rare earth cobalt. As the form of the mouth frame or one-way valve using this permanent magnet powder,
The following (A) to (C) can be exemplified.

(A) The entire mouth frame (or the one-way valve) is molded with a synthetic resin or rubber (so-called bond magnet) containing a permanent magnet powder or granular material made of the alloy, metal oxide or intermetallic compound. . The permanent magnet means is magnetized after the mouth frame (or one-way valve) is molded.

(B) The valve seat portion and the hanging member (or the contact portion of the one-way valve) of the mouth frame body are synthetic resins or rubbers containing the permanent magnet powder particles made of the alloy, metal oxide or intermetallic compound. And the other part is formed by simultaneously molding (so-called two-color molding) the mouth frame (or one-way valve) using a synthetic resin or rubber containing no permanent magnet powder. The permanent magnet means is magnetized after the mouth frame (or one-way valve) is molded.

(C) A permanent magnet powder made of the alloy, the metal oxide, or the intermetallic compound is applied to the valve seat portion and the suspension member (or the contact portion of the one-way valve) of the mouth frame formed of synthetic resin or the like. A permanent magnet member made of contained synthetic resin or rubber is attached by being adhered with an adhesive or by engaging with an engaging groove formed in the valve seat portion and the hanging member (or abutting portion). . The permanent magnet means is magnetized before or after attachment to the mouth frame (or one-way valve).

Further, the "magnetically attractable powder or granular material" is formed of a material that magnetically attracts the permanent magnet powder or granular material,
Iron, cobalt, nickel, rare earth metals, silicon steel containing or not containing these metals, alloys such as permalloy and amorphous alloys, metal oxides such as soft ferrite (soft magnetic ferrite), or metal-to-metal The thing which consists of a compound can be illustrated. The following (α) to (γ) can be exemplified as the mode of forming the mouth frame or the one-way valve using this magnetically attractable powder.

(Α) The entire mouth frame (or the one-way valve) is molded with a synthetic resin or rubber containing a magnetically attractable powder or granular material composed of the metal, alloy, metal oxide or intermetallic compound.

(Β) The valve seat portion and the bridging member (or the contact portion of the one-way valve) of the mouth frame body are synthetic materials containing the magnetically attractable powdery particles made of the metal, alloy, metal oxide or intermetallic compound. The mouth frame (or one-way valve) is simultaneously molded (so-called two-color molding) by using resin or rubber, and the other part by using synthetic resin or rubber that does not contain magnetic adsorptive powder. thing.

(Γ) Magnetic adsorbing powder made of the metal, alloy, metal oxide, or intermetallic compound on the valve seat portion and the bridging member (or the contact portion of the one-way valve) of the mouth frame formed of synthetic resin or the like. Attach by attaching a magnetically attracting member made of synthetic resin or rubber containing granules with an adhesive or engaging with an engaging groove formed in the valve seat portion and the hanging member (or abutting portion) Things that become.

The content of the permanent magnet powder or magnetically attractable powder in the synthetic resin or rubber is, for example, 1 to 6 g / cm ³
Can be Also, the powder particle size of each powder is
For example, it can be selected from the range of 0.1 to 50 μm.

Further, it is preferable that the magnetic attraction force between the valve seat portion and the bridging member of the mouth frame and the contact portion of the one-way valve is set within a range of ^{2 to} 10 g / cm ² . This is because, if the magnetic attraction force is so strong as to exceed the range, for example, the one-way valve does not swing due to the action of the negative pressure generated when the vehicle is running, and the inside air discharge port cannot be opened.
This is because if the magnetic attraction force is too weak to fall within this range, the one-way valve will swing and open the inside air discharge port, for example, only due to vibrations generated when the vehicle is running.

[Operation] According to the ventilation device of the present invention, the one-way valve closes the inside air discharge port of the mouth frame except when the inside air is discharged to the outside of the room. At this time, the valve seat portion and the hanging member of the mouth frame body and the contact portion of the one-way valve are magnetically attracted by the above-mentioned means (when the own weight of the one-way valve acts on the valve seat portion, The abutment force is also added.), And the abutment portion of the one-way valve comes into close contact with the valve seat portion and the hanging member while maintaining a high sealing property.

Here, the hanging member mechanically supports and prevents the one-way valve from being deformed so as to bite into the inside air discharge port, and is also deformed so that the one-way valve is wavy (particularly at the corners thereof). The magnetic attraction force suppresses the tendency of a part of the valve seat portion to lift up from the valve seat portion).

Due to the above-mentioned action, even if the thickness of the one-way valve is thin, there is no gap between the one-way valve and the valve seat portion. It won't open. Therefore, it is possible to prevent the contaminated outside air including dust, dust, smoke, odor, etc. from flowing back into the room from the inside air discharge port.

Next, for example, when the atmospheric pressure difference between the inside and the outside of the vehicle becomes large enough to overcome the magnetic attraction force and the self-weight of the one-way valve due to the negative pressure generated on the vehicle body surface when the vehicle is running, the one-way valve causes the valve seat to move. The inside air discharge port is opened only in the direction in which the inside air is discharged to the outside by swinging to the outside of the room away from the section and the hanging member. Therefore, it is possible to discharge the inside air, which is contaminated by cigarette smoke or the exhaled air of a person, from the inside air outlet to the outside of the room.

[Embodiment] An embodiment in which the present invention is embodied in a vehicle exhaust system will be described below with reference to the drawings.

As shown in FIG. 1 to FIG. 5, this ventilation device is configured to take in the inside air R of an interior B of an automobile and introduce it to the next inside air exhaust port, and the inside air R to the outside C. A mouth frame 2 having six inner air outlets for discharging, their peripheral portions, and a bridging member that hangs three at each inner air outlet, and the inner air only when the inner air R is discharged to the outside C. It is composed of six one-way valves 4 attached to the mouth frame 2 so as to open the discharge port, and a member or structure for attaching these members to each other. Further, the mouth frame 2 contains the permanent magnet powder particles 3, and the one-way valve 4 contains the magnetically attractable powder particles 5. Details of these components are as follows.

(Internal Air Introduction Duct) As shown in FIGS. 2 and 4, the internal air introduction duct 1 extends obliquely downward from an internal airflow inlet 11 having an opening at the upper end, and is further bent and extends laterally. Duct body 12,
A rectangular frame-shaped flange base portion 13 provided at the base end of the duct body 12 for attaching the entire ventilation device to the vehicle body A of an automobile is integrally formed of polypropylene resin. Inside the base end of the duct body 12, a stepped frame-shaped mounting portion 14 for mounting the mouth frame body 2 described in detail below is formed, and the mounting portion 14 has a plurality of mounting projections 15
Are formed.

(Mouth frame body) As shown in FIGS. 2 and 4, the mouth frame body 2 is approximately
There are two upper and lower inclined walls 21 having an inclination angle of 60 degrees, upper and lower two rows of vertical walls 22 connected to the upper end of each inclined wall 21, upper upper inclined walls 21 and lower vertical walls 22. The horizontal wall 23 to connect,
Metal oxide-based permanent magnet powder 3 (for example, hard ferrite manufactured by Toda Kogyo Co., Ltd., product number FS-317, powder particle size)
0.8 to 2 μm) to 20 to 80 vol (volume)% (more preferably,
It is integrally molded with a polypropylene resin containing 40 to 60 vol (volume)%. Each sloped wall
The reference numeral 21 includes three quadrangular inside air discharge ports 24 arranged in the left-right direction (six in total in the upper and lower tiers) and their peripheral edges 25. Most of the peripheral portion 25 constitutes the valve seat portion 20 with which the one-way valve 4 abuts. Further, between the corners of the inside air discharge ports 24 that are diagonally opposed to each other, and between the center of the upper side and the center of the lower side, a total of three hanging members 26 with which the one-way valve 4 abuts are provided on the peripheral edge portion 25. The bridging members 26 intersect each other at the center of the inside air discharge port 24 and are integrated with each other. These hanging members 26
Needless to say, it contains the permanent magnet powder particles 3.

The permanent magnet powder particles 3 in the mouth frame 2 are magnetized after the mouth frame 2 is molded, and the magnetic force thereof is 30 to 2000 G (gauss) (more preferably 100 to 200 G).

Each vertical wall 22 has a duct 1 for introducing the inside air.
A plurality of mounting holes 27 for inserting and mounting in the mounting protrusions 15 of the mounting portion 14 and a plurality of mounting protrusions 28 for mounting the one-way valve 4 described in detail later are formed.

The mouth frame body 2 configured as described above is attached to the attachment portion 14 of the inside air introducing duct 1 as follows. That is, first, the mouth frame body 2 is placed on the mounting portion 14 from the outdoor side, and the mounting projection 15 of the mounting portion 14 is mounted on the mounting hole of the vertical wall 22.
Insert it into 27. Next, the top portion of the mounting projection 15 is heated and melted to be fused or fixed to the vertical wall 22, so that the mouth frame body 2 is attached so as not to separate. The mouth frame 2 is attached after the next six one-way valves 4 are attached to the mouth frame 2.

(One-way valve) As shown in FIG. 1 and FIG. 2, the one-way valve 4 has a metal oxide-based magnetic adsorptive powder 5 (for example, soft ferrite, powder particle size 0.8 to 2 μm) of 20 to 20 μm. It is integrally molded as a thin plate with a thickness of about 0.5 mm forming a quadrangle larger than the inside air discharge port 24 by chloroprene rubber containing 80 vol (volume)% (more preferably 40 to 60 vol (volume)%). . The upper end of the one-way valve 4 is provided with a plurality of mounting holes 41 for inserting and mounting the mounting projections 28 on the vertical wall 22 of the mouth frame 2.

The one-way valve 4 has a specific gravity of 1.3 to 3.5 (more preferably 1.5 to 3.0). The magnetically attractable powder particles 5 contained in the contact portion 40 of the one-way valve 4 are the permanent magnet powder particles 3 contained in the valve seat portion 20 and the suspension member 26.
The force of magnetic attraction to is set to about 4 to 7 g / cm ² .

The one-way valve 4 configured as described above is attached to the surface of the mouth frame 2 on the outdoor side as follows. That is, first, the one-way valve 4 is applied from the outdoor side to the inclined wall 21 so as to close the inside air discharge port 24,
The vertical wall is attached to the mounting hole 41 at the upper end of the one-way valve 4.
Insert the mounting protrusion 28 of 22. Next, the retainer 6 formed of a polypropylene resin in the shape of an elongated plate is placed on the upper end of the one-way valve 4, and the retainer 6 has a mounting hole.
The mounting protrusion 28 of the vertical wall 22 is inserted into 61. continue,
The top portion of the mounting projection 28 is heated and melted to be fused or fixed to the retainer 6, so that the upper end portion of the one-way valve 4 and the retainer 6 are attached to the vertical wall 22 without being separated.

Therefore, as shown in FIG. 5, the one-way valve 4 has a mounting portion 42 (specifically, a boundary between the one-way valve 4 and the lower edge of the retainer 6) except for an upper end portion mounted on the vertical wall 22. The one-way valve 4 itself can swing about the contact portion) by the elastic force of the one-way valve 4 itself.

The one-way valve 4 allows the inside air R to flow outside C
A state in which the inside air discharge port 24 is reliably sealed by the contact force of the contact portion 40 that acts on the valve seat portion 20 and the hanging member 26 by its own weight and the magnetic attraction force, except when discharged to When the air pressure chambers of the indoor B and the outdoor C have a size that overcomes the self-weight of the one-way valve 4 and the magnetic attraction force, the air chambers are separated from the valve seat portion 20 and the hanging member 26 to the outdoor side. The inside air discharge port 24 can be opened only in the direction of swinging and discharging the inside air R to the outside C.

(Operation and Effect of Embodiment) According to the ventilation device of the present embodiment configured as described above, the one-way valve 4 causes the inside air of the mouth frame body 2 to be discharged except when the inside air R is discharged to the outside C. Exit 24 is closed.
At this time, the contact portion 40 of the one-way valve 4 is
The valve seat portion 20 and the three suspension members 26 are not only brought into contact with each other by their own weight, but also the magnetically attractable powder particle pair 5 contained in the corresponding contact portion 40 causes the valve seat portion 20 and the suspension member 26. Due to the magnetic attraction force to the permanent magnet powder particles 3 contained in the above, it adheres to the valve seat portion 20 and the hanging member 26 while maintaining a high sealing property.

Here, the three hanging members 26 mechanically prevent the one-way valve 4 from deforming so as to bite into the inside air outlet 24, and at the same time, deform the one-way valve 4 so as to wavy. The effect of suppressing the above (particularly wrinkles near the four corners and attempting to partially lift up from the valve seat portion 20) is suppressed by the magnetic attraction force.

By the above-mentioned use, even if the thickness of the one-way valve 4 is thin, no gap is generated between the one-way valve 4 and the valve seat portion 20. It does not open the exit 24. Therefore, it is possible to prevent the contaminated outside air including dust, dust, smoke, odor, etc. from flowing back from the inside air outlet 24 into the room B.

Next, due to the negative pressure or the like generated on the vehicle body surface when the vehicle is running, the pressure difference between the inside B and the outside C of the one-way valve 4
When the size of the one-way valve 4 overcomes the self-weight and the magnetic attraction force, the one-way valve 4 swings away from the valve seat portion 20 and the hanging member 26 to the outside (in the direction of arrow S2 in FIG. 5), The inside air discharge port is provided only in the direction in which the inside air R is discharged to the outside of the room.
Open 24 Therefore, the inside air R, which is contaminated by cigarette smoke or human breath, can be discharged from the inside air discharge port 24 to the outside C.

When the pressure difference between the room B and the room C becomes smaller due to the weight of the one-way valve 4, the one-way valve 4 swings toward the inside air outlet side (direction of arrow S1 in FIG. 5) due to its own weight, The seat portion 20 and the hanging member 26 are again brought into close contact with each other.

The present invention is not limited to the configurations of the above-described embodiments, and can be embodied by being arbitrarily modified without departing from the spirit of the invention.

(1) As shown in FIGS. 6 and 7, a single spanning member 26 is provided in the mouth frame 2 so as to traverse the inside air discharge port 24.

(2) As shown in FIGS. 8 and 9, the mouth frame 2 is provided with two hanging members 26 that intersect at one point in the inside air discharge port 24.

(3) As shown in FIG. 10, the inside air discharge port is provided in the mouth frame body 2.
Provide three hanging members 26 that intersect at two points in 24.

(4) As shown in FIG. 11, the inside air outlet is provided in the mouth frame 2.
Provide three suspension members 26 that do not intersect within 24.

EFFECTS OF THE INVENTION Since the ventilation device of the present invention is configured as described above, the adhesion between the mouth frame and the one-way valve is guaranteed by the magnetic attraction force when the inside air is not discharged to the outside of the room, and the one-way valve is used. The valve can be prevented from being deformed, and the inside air discharge port of the mouth frame can be securely closed with a one-way valve to prevent the dirty outside air from flowing back into the room from the inside air discharge port. it can. Further, both the mouth frame and the one-way valve can be formed lightweight and inexpensive, and the magnetic attraction force between the two can easily be kept within a range in which the one-way valve opens due to the atmospheric pressure difference between the inside and the outside of the room.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a ventilation device according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of the ventilation device as a whole.
The figure is also a front view, FIG. 4 is a sectional view taken along the line II in FIG. 3, FIG. 5 is an enlarged sectional view taken along the line II-II in FIG. 3, and FIGS. It is a partial front view which shows an example. 1 ... Inside air introduction duct, 2 ... Port frame, 3 ... Permanent magnet powder, 4 ... One-way valve, 5 ... Magnetically attractable powder, 20 ... Valve seat, 24 ... Inside air discharge port, 25 ...... peripheral part, 26 …… hanging member, 40 …… contact part, B …… indoor, C …… outdoor, R …… inside air.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-56-9130 (JP, A) real-opening Sho-56-68833 (JP, U) real-opening Sho-58-106215 (JP, U) real public Sho-62- 9130 (JP, Y1)

Claims (1)

[Claims] 1. A mouth frame having an inside air discharge port for discharging the inside air of the room to the outside, and a peripheral portion of the inside air discharge port as a valve seat except when the inside air of the room is discharged to the outside. A one-way valve that abuts and closes the inside air discharge port, and when the inside air inside the room is discharged to the outside, separates from the valve seat portion and opens the inside air discharge port only in the discharging direction due to a pressure difference between the inside and the outside of the room In the ventilator, the mouth frame is provided with a hanging member that hangs on the inside air discharge port, and at least the valve seat portion and the hanging member of the mouth frame are made of a resin containing magnetic powder particles. At least the contact portion of the one-way valve with respect to the valve seat portion and the hanging member is formed of rubber or elastomer containing magnetic powder particles, and the magnetic powder particles of the valve seat portion and the hanging member or the contact member At least part of the magnetic powder One of the magnets is a magnetized permanent magnet powder, and the magnetic attraction force between the abutment portion and the valve seat portion and the hanging member is ² to 10 g / cm2.