Title of Invention

ELECTROMAGNETIC FLUID CONTROL VALVE

Abstract An electromagnetic fluid control valve includes: a solenoid portion for generating electromagnetic attraction disposed inside an intake air pipe through which air flows; a valve portion disposed integrally with the solenoid portion, the valve portion having a valve head that is placed in contact with and separated from a seat portion by the electromagnetic attraction, the seat portion being formed on an inner wall surface of the intake air pipe; and an expandable bellows constituting a volume chamber together with the valve head, and communicating with an engine side through conducting apertures formed on the valve head to cancel out pressure differences between an upstream side and a downstream side of the valve head, wherein: an air circulating means enabling air to flow through the conducting apertures from the upstream side of the valve head to the downstream side is disposed in the valve portion.
Full Text

ELECTROMAGNETIC FLUID CONTROL VALVE
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electromagnetic fluid control valve in which a valve portion is operated by electromagnetic attraction generated in a solenoid portion to control flow rate of a fluid.
2. Description of the Related Art
Electronically-controlled throttle valves generally performing flow control using a disk-shaped butterfly valve are frequently used as fluid control valves for controlling flow rate of air supplied to an engine.
These butterfly valves are driven by an electric motor via internal reduction gears, but there are cases in which foreign matter contained in intake air, gas blown back from the engine, etc., accumulates on an outer periphery of the butterfly valve over time, and the degree of valve opening is substantially reduced for minute degrees of opening due to the effects of the accumulation of foreign matter, preventing a predetermined flow rate from being obtained.
In idle speed control valves (hereinafter "ISC valves") for controlling idle rotational frequency of an engine that are used together with throttle valves having a butterfly valve mechanically pulled in connection with accelerator operation and are disposed in a bypass flow channel configured separately from the airflow channel controlled by the throttle valve, flow rate control valves of an electromagnetic valve type in which a valve body is actuated directly by electromagnetic attraction are also commonly-known, and an amount of valve head lift for obtaining a supplied air flow rate required to maintain idling is controlled by a value of an electric current exciting the electromagnetic valve. (See Patent Literature 1, for example.) Patent Literature
Japanese Patent Laid-Open No. HEI 10-47523 (Gazette)
However, in the case of these ISC valves, a volume chamber for canceling out fluid dynamic forces due to pressure differences acting on the valve head may be disposed in order to use the electromagnetic attraction efficiently, but one problem has been that foreign matter contained in gas blown back from the engine, etc., passes through conducting apertures formed on the valve head and accumulates inside the volume chamber, or blocks the conducting apertures, etc., overtime.

SUMMARY OF THE INVENTION
The present invention aims to solve the above problems and an object of the present invention is to provide an electromagnetic fluid control valve preventing foreign matter contained in gas blown back from an engine, etc., from passing through conducting apertures formed on a valve head and accumulating inside a volume chamber, or blocking the conducting apertures, etc., overtime
In order to achieve the above object, according to one aspect of the present invention, there is provided an electromagnetic fluid control valve including: a solenoid portion for generating electromagnetic attraction disposed inside an intake air pipe through which air flows; a valve portion disposed integrally with the solenoid portion, the valve portion having a valve head that is placed in contact with and separated from a seat portion by the electromagnetic attraction, the seat portion being formed on an inner wall surface of the intake air pipe; and an expandable bellows constituting a volume chamber together with the valve head, and communicating with an engine side through conducting apertures formed on the valve head to cancel out pressure differences between an upstream side and a downstream side of the valve head, wherein: an air circulating means enabling air to flow through the conducting apertures from the upstream side of the valve head to the downstream side is disposed in the valve portion.
Using an electromagnetic fluid control valve according to the present invention, foreign matter contained in gas blown back from an engine, etc., can be prevented from passing through conducting apertures formed on a valve head and accumulating inside a volume chamber, or blocking the conducting apertures, etc., overtime.

BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a cross section showing an electromagnetic fluid control valve according to Embodiment 1 of the present invention;
Figure 2 is a cross section showing an electromagnetic fluid control valve according to Embodiment 2 of the present invention; and
Figure 3 is a partial enlargement of Figure 2.DETAILED
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferred embodiments of the present invention will now be explained based on drawings, and identical or corresponding members and portions will be given identical numbering. Embodiment 1
Figure 1 is a cross section showing an electromagnetic fluid control valve (hereinafter "electromagnetic valve") according to Embodiment 1 of the present invention.
This electromagnetic valve includes: a solenoid portion 1 for generating electromagnetic attraction; and a valve portion 2 driven by this electromagnetic attraction. The solenoid portion 1 and the valve portion 2 are enveloped by a body 3 functioning as an intake air pipe.
The body 3 constitutes a portion of an intake air pipe constituting piping, an upstream body portion 3a and a downstream body portion 3b being integrated by four bolts 21 with a gasket 17 and a plate 15 (described below) interposed. The body 3 is mounted coaxially to an intake air pipe partway along the intake air pipe to an engine (not shown).
In the solenoid portion 1, a cylindrical core 4 is disposed so as to be coaxial with the intake air pipe. A solenoid coil 5 is installed on an outer periphery of the core 4 by means of a bobbin 22. The solenoid coil 5 enveloped by a yoke 6. The bobbin 22 is integrated with a connector 24 having terminals 23 using a resin.
A radially-projecting flange portion 8 is formed on an end portion of the core 4 that is at a downstream end when the core is inserted into a penetrating aperture of the bobbin 22 and fixed. The yoke 6 and the core 4 are integrated simply by crimping an edge portion at an open end of the yoke 6 onto an outer peripheral edge portion of this flange portion 8.
The valve portion 2 includes: a plunger 7 disposed in an interior portion at a downstream end of the core 4 so as to be slidable in an axial

direction, the plunger 7 having a cylindrical pipe 9; a valve head 10 fixed to a downstream end portion of the pipe 9, the valve head 10 having conducting apertures 13; an adjusting screw 19 screwed into an upstream end of the core 4, the adjusting screw 19 moving forward or backward along an axis of the core 4 by rotation; and a spring 20 disposed between the adjusting screw 19 and the pipe 9, the spring forcing the plunger 7 toward the valve head 10.
A first air circulating aperture 30 is formed in the adjusting screw 19 in an axial direction. An orifice 31 for adjusting an air flow rate is formed in a leading end portion at a downstream end of the first air circulating aperture 30. The first air circulating aperture 30 and second air circulating apertures 11 formed on side surfaces of the cylindrical pipe 9 together constitute an air circulating means.
A bellows 12 formed using a low-rigidity resin material and having a volume chamber in an interior portion is fixed to an upstream outer peripheral edge portion of the valve head 10. This bellows 12 has an axially-expandable concertina portion 25. A flange 27 is formed on an upstream end portion of the bellows 12, and this flange 27 is held between the flange portion 8 of the core 4 and a ring 26 press-fitted into a stepped portion at a downstream end of the flange portion 8.
The volume chamber of the bellows 12 and interior portions of the core 4 and the plunger 7 all communicate with a negative pressure side of the engine via the conducting apertures 13 of the valve head 10 and the second air circulating apertures 11 of the pipe 9, making pressure generally equal on upstream surfaces and downstream surfaces of the valve head 10, thereby eliminating actuation of the plunger 7 and the valve head 10 by pressure differences.
An inner peripheral edge portion of a ring-shaped plate 15 having a plurality of passage apertures 16 having a total aperture surface area sufficiently larger than an aperture surface area of the valve head 10 is held between the flange portion 8 of the core 4 and the bobbin 22. An outer peripheral edge portion of this plate 15 is held between the upstream body portion 3a and the downstream body portion 3b.
In an electromagnetic valve of the above configuration, peripheral edge portions of the plate 15 are held between the upstream body portion 3a and the downstream body portion 3b with the gasket 17 interposed with the solenoid portion 1, the valve portion 2, the bellows 12, and the plate 15

integrated with each other.
At this time, the valve head 10 contacts a seat portion 18 formed on an inner wall surface of the downstream body portion 3b. Next, the valve head 10 is set to so as to obtain a predetermined amount of lift relative to the seat portion 18 by rotating the adjusting screw 19 to move the adjusting screw 19 forward or backward relative to the core 4 to adjust elastic force in the spring 20 disposed between the adjusting screw 19 and the pipe 9.
Next, action of an electromagnetic valve of the above configuration will be explained.
Until an electric current is passed through the solenoid coil 5, the valve head 10 is placed in contact with the seat portion 18 by the combined force of the spring 20 and the bellows 12.
When an electric current is passed through the solenoid coil 5 via an electronic control unit (not shown), magnetic lines of force flow along a magnetic circuit constituted by the core 4, the yoke 6, and the plunger 7, generating a force in the core 4 proportional to the electric current value that attracts the plunger 7 away from the seat portion 18. Because of this, the plunger 7 is magnetically attracted to the core 4, the valve head 10 is lifted to a position of balance between the magnetic attraction and reaction due to the combined force of the spring 20 and the bellows 12, the pipe 9 and the valve head 10 integrated with the plunger 7 move in an axial direction, and as a result the valve head 10 is separated from the seat portion 18.
At the same time, a pressure difference arises inside the intake air pipe due to negative pressure suction from an engine generated by operation of cylinders (not shown), and air inside the intake air pipe flows around the upstream body portion 3a and the yoke 6, around the passage apertures 16 of the plate 15 and the bellows 12, and through an outflow aperture 28 toward the engine.
A minute airflow flows constantly through the orifice 31 of the first air circulating aperture 30, the interior portions of the core 4 and the plunger 7, the second air circulating apertures 11, the volume chamber inside the bellows 12, and the conducting apertures 13 of the valve head 10 toward the engine.
Here, because a proportional solenoid coil is used for the solenoid coil 5, the air flow rate through the outflow aperture 28 toward the engine is adjustable by controlling the electric current applied to the solenoid coil 5. The required air flow rate is determined by the degree of accelerator opening,

rotational frequency of the engine, torque, etc.
The flow rate of the minute airflow is determined by the diameter of the orifice 31. When engine starting by battery power is impossible, such as when battery voltage is low or the battery is flat in a motorcycle, etc., kick starting may be required, and the flow rate of this minute airflow is an amount ensuring a minimum airflow rate required for such engine ignition.
In an electromagnetic valve according to this embodiment, since a minute airflow is constantly present in the volume chamber of the bellows 12 to cancel out the pressure differences on upstream and downstream sides of the valve head 10, penetration into the volume chamber by gas flowing back from the engine is reduced.
Since foreign matter that has entered the volume chamber is also constantly blown downstream by this minute airflow, foreign matter is prevented from accumulating in the volume chamber, and blockage of the conducting apertures 13 of the valve head 10 is also prevented.
In addition, if undervoltages arise in a motorcycle due to battery deterioration, etc., kick starting may be required, but the flow rate of air required for engine ignition in such cases is ensured. Embodiment 2
Figure 2 is a cross section showing an electromagnetic fluid control valve according to Embodiment 2 of the present invention, and Figure 3 is a partial enlargement of Figure 2.
In this embodiment, an adjusting screw 19 includes a valve 32 disposed internally enabling a flow channel cross-sectional area of a first air circulating aperture to be modified.
The valve 32 is screwed into the adjusting screw 19 while being forced upstream by a valve spring 33. A passage 35 through which air passes along a central axis and a plurality of the apertures 34 penetrating through perpendicular to the passage 35 are formed in the valve 32, a first air circulating aperture being constituted by the passage 35 and the apertures 34.
Using this electromagnetic valve, the valve 32 is movable forward or backward along a central axis of the adjusting screw 19 by rotation, and a degree of opening between corner portions 37 of the valve 32 and corner portions 36 at a downstream end of the adjusting screw 19 can be adjusted by the amount of insertion by screwing, enabling the flow rate of air flowing into the volume chamber to be adjusted simply by adjusting this degree of opening.

Consequently, even if foreign matter accumulates on inner wall surfaces of the conducting apertures 13 of the valve head 10, and the diameters of the conducting apertures 13 are reduced, an optimum minute flow rate can be ensured by adjusting the amount of insertion of the valve 32 by screwing.
Moreover, in each of the above embodiments, the electromagnetic valve is disposed inside a body 3 constituting a portion of an intake air pipe, but the electromagnetic valve may also be disposed in an intake air pipe constituting a separate bypass passage from an airflow channel controlled by a throttle valve.
For the air circulating means, first air circulating apertures 30, 34, and 35 are formed in the adjusting screw 19 constituting a component member of the valve portion 2, and second air circulating apertures 11 are formed in the pipe 9 of the plunger 7 constituting a component member of the valve portion 2, but of course the air circulating means is not limited to this construction provided that it is possible for air to flow from an upstream side of the valve head to a downstream side through the conducting apertures 13 of the valve head 10.





WHAT IS CLAIMED IS:
1. An electromagnetic fluid control valve comprising:
a solenoid portion for generating electromagnetic attraction disposed inside an intake air pipe through which airflows;
a valve portion disposed integrally with said solenoid portion, said valve portion having a valve head that is placed in contact with and separated from a seat portion by said electromagnetic attraction, said seat portion being formed on an inner wall surface of said intake air pipe; and
an expandable bellows constituting a volume chamber together with said valve head, and communicating with an engine side through conducting apertures formed on said valve head to cancel out pressure differences between an upstream side and a downstream side of said valve head,
wherein:
an air circulating means enabling air to flow through said conducting apertures from said upstream side of said valve head to said downstream side is disposed in said valve portion.
2. The electromagnetic fluid control valve according to Claim 1, wherein:
said solenoid portion has:
a core;
a solenoid coil disposed outside said core; and
a yoke covering said solenoid coil; said valve portion has:
a plunger integrated with said valve head so as to be slidable relative to said core;
an adjusting screw screwed into said core, and moving forward or backward by rotation; and
a spring disposed between said adjusting screw and said plunger for forcing said valve head against said seat portion; and said air circulating means is constituted by:
a first air circulating aperture disposed in said adjusting screw; and
a second air circulating aperture formed in said plunger.
3. The electromagnetic fluid control valve according to Claim 2, wherein:
said adjusting screw comprises a valve disposed internally that

enables a flow channel cross-sectional area of said first air circulating aperture to be modified.
4. The electromagnetic fluid control valve according to either of Claims 2 or 3, wherein:
said flow channel cross-sectional area of said first air circulating aperture has a size enabling a minimum flow rate of air required to start an engine to flow toward said engine even when said valve head is closed.


Documents:

0917-che-2005-abstract.pdf

0917-che-2005-claims.pdf

0917-che-2005-correspondnece-others.pdf

0917-che-2005-description(complete).pdf

0917-che-2005-drawings.pdf

0917-che-2005-form 1.pdf

0917-che-2005-form 26.pdf

0917-che-2005-form 3.pdf

0917-che-2005-form 5.pdf

0917-che-2005-others.pdf

917-CHE-2005 AMENDED CLAIMS 05-09-2011.pdf

917-CHE-2005 FORM-3 05-09-2011.pdf

917-CHE-2005 POWER OF ATTORNEY 05-09-2011.pdf

917-CHE-2005 EXAMINATION REPORT REPLY RECEIVED 05-09-2011.pdf


Patent Number 249234
Indian Patent Application Number 917/CHE/2005
PG Journal Number 41/2011
Publication Date 14-Oct-2011
Grant Date 12-Oct-2011
Date of Filing 11-Jul-2005
Name of Patentee MITSUBISHI DENKI KABUSHIKI KAISHA
Applicant Address 2-3, MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100-8310, JAPAN
Inventors:
# Inventor's Name Inventor's Address
1 URYU, TAKUYA MITSUBISHI DENKI KABUSHIKI KAISHA 2-3, MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100-8310, JAPAN
2 ONISHI, YOSHIHIKO MITSUBISHI DENKI KABUSHIKI KAISHA 2-3, MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100-8310, JAPAN
3 NAKAO, KENJI MITSUBISHI DENKI KABUSHIKI KAISHA 2-3, MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100-8310, JAPAN
4 UNO, SHIGEKI C/O MITSUBISHI ELECTRIC CONTROL, SOFTWARE CO., LTD., 1-2, HAMAYAMA-DORI, 6-CHOME, HYOGO-KU, KOBE-SHI, HYOGO 652-0871 JAPAN
PCT International Classification Number F16K 31/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2004-330721 2004-11-15 Japan