U.S. patent application number 11/819092 was filed with the patent office on 2008-06-26 for electromagnetic valve device and fuel injection apparatus with the valve device.
Invention is credited to Hisao Ogawa, Masaki Toda.
Application Number | 20080149071 11/819092 |
Document ID | / |
Family ID | 39430088 |
Filed Date | 2008-06-26 |
United States Patent
Application |
20080149071 |
Kind Code |
A1 |
Ogawa; Hisao ; et
al. |
June 26, 2008 |
ELECTROMAGNETIC VALVE DEVICE AND FUEL INJECTION APPARATUS WITH THE
VALVE DEVICE
Abstract
A compact electromagnetic valve device for fuel injection
apparatus for engines is provided with which occurrence of
cavitation erosion due to rapid change in pressure in a small gap
is prevented without increasing in size. Through holes are drilled
in a platy armature connected to a poppet valve for opening and
closing a fuel passage connecting a fuel feed/spill passage to a
plunger room of a fuel injection apparatus, and a thin plate valve
or check valve is provided to the armature to allow the holes to be
opened or closed in accordance with upward or down ward movement of
the armature connected with the popped valve.
Inventors: |
Ogawa; Hisao; (Kanagawa-ken,
JP) ; Toda; Masaki; (Kanagawa-ken, JP) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
2033 K STREET N. W., SUITE 800
WASHINGTON
DC
20006-1021
US
|
Family ID: |
39430088 |
Appl. No.: |
11/819092 |
Filed: |
June 25, 2007 |
Current U.S.
Class: |
123/476 ;
239/585.1; 251/129.16 |
Current CPC
Class: |
F16K 31/0693 20130101;
F16K 25/04 20130101; F02M 57/023 20130101; F02M 59/366 20130101;
F02M 63/0015 20130101; F02M 63/004 20130101; F02M 2200/04
20130101 |
Class at
Publication: |
123/476 ;
239/585.1; 251/129.16 |
International
Class: |
F02D 1/16 20060101
F02D001/16; F02M 51/06 20060101 F02M051/06; H01F 7/16 20060101
H01F007/16 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 20, 2006 |
JP |
2006-342183 |
Claims
1. An electromagnetic valve device comprising a platy armature
connected to an end of a valve body for opening and closing a fluid
passage, a solenoid device for attracting said armature by
attraction force generated by energizing a solenoid coil of said
solenoid device when allowing said valve body to close said fluid
passage and releasing the attraction force by de-enegizing the
solenoid coil when allowing said valve body to be returned to an
opening position at which the valve body opens said fluid passage,
and a return spring for pushing said valve body to said opening
position, wherein through holes are drilled in said armature
penetrating from a front surface thereof facing an end surface of
said solenoid device to a rear surface thereof, a thin plate valve
is attached to said rear surface of said armature to cover said
holes, whereby when said armature is attracted by said solenoid
device said thin plate valve is bent to open said through holes by
pressure exerting on said thin plate valve through said holes from
a small gap space between said end face of said solenoid valve
device and said front surface of said armature so that said small
gap space is brought into communication with an armature room where
said armature is located, and when said armature returns to said
opening position pushed by said return spring said thin plate valve
recovers its original position to close said holes.
2. A fuel injection apparatus for engines equipped with an
electromagnetic valve of claim 1, wherein the apparatus is composed
such that a plunger room thereof is discommunicated or communicated
with a fuel feed/spill passage when a poppet valve as said valve
body is seated on or departed from a seat face of a valve seat,
whereby fuel injection begins when said solenoid device is
energized so that said poppet valve closes said fluid passage to
shutoff communication between said plunger room and said fuel
feed/spill passage, and fuel injection ends when said solenoid
device is de-energized so that said poppet valve opens said fluid
passage pushed by said return spring to bring said plunger room
into communication with said fuel feed/spill passage.
3. An electromagnetic valve device comprising a platy armature
connected to a valve body for opening and closing a fluid passage,
a solenoid device for attracting said armature by attraction force
generated by energizing a solenoid coil of said solenoid device
when allowing said valve body to close said fluid passage and
releasing the attraction force by de-enegizing the solenoid coil
when allowing said valve body to be returned to an opening position
at which the valve body opens said fluid passage, and a return
spring for pushing said valve body to said opening position,
wherein through holes are drilled in said armature penetrating from
a front surface thereof facing an end surface of said solenoid
device to a rear surface thereof, a check valve is provided at a
connecting part of said armature to said valve body to open or
close said holes so that a small gap space between said end face of
said solenoid valve device and said front surface of said armature
is communicated or discommunicated with an armature room where said
armature is located, whereby when said armature is attracted by
said solenoid device to be moved upward said check valve opens said
holes pushed by pressure in said small gap space increased by
upward movement of said armature aided by negative pressure
generated in said central hollow of said poppet valve due to upward
movement thereof so that said small gap space is brought into
communication with said armature room, and when said valve body is
moved down by said return spring said check valve closes said holes
pushed by a return spring of said check valve aided by positive
pressure generated in said central hollow of said poppet valve due
to downward movement thereof so that said small gap space is
brought into discommunication with said armature room.
4. A fuel injection apparatus for engines equipped with an
electromagnetic valve device of claim 3, wherein the apparatus is
composed such that a plunger room thereof is discommunicated or
communicated with a fuel feed/spill passage when a poppet valve as
said valve body is seated on or departed from a seat face of a
valve seat, whereby fuel injection begins when said solenoid device
is energized so that said poppet valve closes said fluid passage to
shutoff communication between said plunger room and said fuel
feed/spill passage, and fuel injection ends when said solenoid
device is de-energized so that said poppet valve opens said fluid
passage pushed by said return spring to bring said plunger room
into communication with said fuel feed/spill passage.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an electromagnetic valve
device having a platy armature connected to an end of a valve body
for opening and closing a fluid passage, a solenoid device which
attracts the armature by attraction force generated when a solenoid
coil is energized to allow the valve body to close the fluid
passage and releases the armature from the attraction force when
the energization is shutoff, and a return spring which thrusts back
the armature so that the valve body opens the fluid passage when
the energization is shutoff, and a fuel injection apparatus
equipped with the electromagnetic valve device.
[0003] 2. Description of the Related Art
[0004] An electromagnetic valve device having a platy armature
connected to an end of a poppet valve for opening and closing a
fuel passage between a plunger room and fuel spill side, a solenoid
device which attracts the armature by attraction force generated
when a solenoid coil is energized to allow the poppet valve to
close the fuel passage and releases the armature from the
attraction force when the energization is shutoff, and a spring
which thrusts back the armature so that the poppet valve opens the
fluid passage when the energization is shutoff, is widely used in
unit injector type fuel injection apparatuses for diesel engines.
Fuel injection begins when the armature is attracted by the
solenoid device by energizing the solenoid coil and the poppet
valve closes the fuel passage to bring the plunger room into
closeness, and ends when the armature is thrust back by the spring
by shutting off the energization so that the poppet valve opens the
fuel passage to allow the plunger room to be communicated with the
fuel spill side.
[0005] One of such electromagnetic valve device is disclosed in
Japanese Laid-Open Patent Application No. 7-279792 (patent
literature 1).
[0006] This electromagnetic valve device has a platy armature
connected to an end of a needle valve for opening and closing a
fuel passage between a plunger room and fuel spill side, a solenoid
device which attracts the armature by attraction force generated
when a solenoid coil is energized to allow the needle valve to
close the fuel passage and releases the armature from the
attraction force when the energization is shutoff, and a spring
which thrusts back the armature so that the needle valve opens the
fluid passage when the energization is shutoff. With this valve,
fuel injection begins when the armature is attracted by the
solenoid device by energizing the solenoid coil and the needle
valve closes the fuel passage to bring the plunger room into
closeness, and ends when the armature is thrust back by the spring
by shutting off the energization so that the needle valve opens the
fuel passage to allow the plunger room to be communicated with the
fuel feed/spill line.
[0007] The electromagnetic valve device is composed such that a
damper room is formed by an end face of the solenoid device and an
end face of the armature with a small gap between them and an
armature room is formed by the other end face of the armature and
the inner face of the valve casing, and a communicating passage is
provided in the valve casing at a side of the armature to
communicate the armature room with the damper room, a check valve
being provided in the communication passage so that fluid can flow
from the armature room to the damper room and not vice versa.
[0008] When the needle valve closes the fuel passage, the check
valve is closed by increased pressure in the damper room to bring
the damper room into closeness, fuel pressure in the damper room
rises to slow down downward velocity of the needle valve to allow
the needle valve to sit on the valve seat slowly, and occurrence of
bouncing of the needle valve which occurs when the needle valve sit
on the valve seat at high speed is prevented.
[0009] However, when the needle valve moves up to open the fuel
passage, pressure in the armature room rises and pressure in the
damper room decreased rapidly, so fluid in the armature room flows
into the damper room through the check valve at high velocity.
Therefore, cavitation erosion tends to occur on the surface of the
armature facing the damper room. Further, as the communication
passage and check valve are provided in the valve casing at a side
position of the armature, the electromagnetic valve device
necessarily becomes large in size to prepare a space for the
communication passage and check valve.
SUMMARY OF THE INVENTION
[0010] The present invention was made in light of the problems
mentioned above, and object of the invention is to provide a
compact electromagnetic valve device with which occurrence of
cavitation erosion due to rapid change in pressure in a small gap
is prevented without increasing in size and a fuel injection
apparatus equipped with the electromagnetic valve device.
[0011] To attain the object, the present invention proposes an
electromagnetic valve device comprising a platy armature connected
to an end of a valve body for opening and closing a fluid passage,
a solenoid device for attracting said armature by attraction force
generated by energizing a solenoid coil of said solenoid device
when allowing said valve body to close said fluid passage and
releasing the attraction force by de-enegizing the solenoid coil
when allowing said valve body to be returned to an opening position
at which the valve body opens said fluid passage, and a return
spring for pushing said valve body to said opening position,
wherein through holes are drilled in said armature penetrating from
a front surface thereof facing an end surface of said solenoid
device to a rear surface thereof, a thin plate valve is attached to
said rear surface of said armature to cover said holes, whereby
when said armature is attracted by said solenoid device said thin
plate valve is bent to open said through holes by pressure exerting
on said thin plate valve through said holes from a small gap space
between said end face of said solenoid valve device and said front
surface of said armature so that said small gap space is brought
into communication with an armature room where said armature is
located, and when said armature returns to said opening position
pushed by said return spring said thin plate valve recovers its
original position to close said holes.
[0012] A fuel injection apparatus equipped with an electromagnetic
valve device as mentioned above is composed such that a plunger
room thereof is discommunicated or communicated with a fuel
feed/spill passage when a poppet valve as said valve body is seated
on or departed from a seat face of a valve seat, whereby fuel
injection begins when said solenoid device is energized so that
said poppet valve closes said fluid passage to shutoff
communication between said plunger room and said fuel feed/spill
passage, and fuel injection ends when said solenoid device is
de-energized so that said poppet valve opens said fluid passage
pushed by said return spring to bring said plunger room into
communication with said fuel feed/spill passage.
[0013] According to the invention, when allowing fuel injection to
be begun by a fuel injection apparatus of engine, pressure in the
small gap between the end surface of the solenoid core and the
upper surface of the armature facing the end surface of the
solenoid core increases as the armature is attracted upward to
allow the poppet valve to be closed, the through holes in the platy
armature are opened through bending of the thin plate valve which
is attached to the rear surface of the armature to cover the holes
pushed by the raised pressure in the small gap exerting on the thin
plate valve through the holes, and the pressure in the small gap is
bled in to the armature room.
[0014] Therefore, in the course of upward moving of the poppet
valve until it is closed, bending of the thin plate valve increases
due to increased pressure in the small gap and flowage of fluid
from the small gap through the holes increases, so rising of
pressure in the gap 33 becomes slower as the poppet valve moves up.
When the armature moves down, pressure in the small gap decreases
and the through holes are closed by the thin plate valve, so rapid
downward movement of the armature is prevented, the armature moves
down slowly, and occurrence of cavitation on the upper surface of
the armature is prevented.
[0015] The invention also proposes an electromagnetic valve device
comprising a platy armature connected to a valve body for opening
and closing a fluid passage, a solenoid device for attracting said
armature by attraction force generated by energizing a solenoid
coil of said solenoid device when allowing said valve body to close
said fluid passage and releasing the attraction force by
de-enegizing the solenoid coil when allowing said valve body to be
returned to an opening position at which the valve body opens said
fluid passage, and a return spring for pushing said valve body to
said opening position, wherein through holes are drilled in said
armature penetrating from a front surface thereof facing an end
surface of said solenoid device to a rear surface thereof, a check
valve is provided at a connecting part of said armature to said
valve body to open or close said holes so that a small gap space
between said end face of said solenoid valve device and said front
surface of said armature is communicated or discommunicated with an
armature room where said armature is located, whereby when said
armature is attracted by said solenoid device to be moved upward
said check valve opens said holes pushed by pressure in said small
gap space increased by upward movement of said armature aided by
negative pressure generated in said central hollow of said poppet
valve due to upward movement thereof so that said small gap space
is brought into communication with said armature room, and when
said valve body is moved down by said return spring said check
valve closes said holes pushed by a return spring of said check
valve aided by positive pressure generated in said central hollow
of said poppet valve due to downward movement thereof so that said
small gap space is brought into discommunication with said armature
room.
[0016] A fuel injection apparatus equipped with an electromagnetic
valve device as mentioned above is composed such that a plunger
room thereof is discommunicated or communicated with a fuel
feed/spill passage when a poppet valve as said valve body is seated
on or departed from a seat face of a valve seat, whereby fuel
injection begins when said solenoid device is energized so that
said poppet valve closes said fluid passage to shutoff
communication between said plunger room and said fuel feed/spill
passage, and fuel injection ends when said solenoid device is
de-energized so that said poppet valve opens said fluid passage
pushed by said return spring to bring said plunger room into
communication with said fuel feed/spill passage.
[0017] According to the invention, when allowing fuel injection to
be begun by a fuel injection apparatus of engine, pressure in the
small gap between the end surface of the solenoid core and the
upper surface of the armature facing the end surface of the
solenoid device increases as the armature is attracted upward to
allow the poppet valve to be closed, the check valve provided at a
connecting part of the armature to the valve body is opened by
pressure in the small gap space increased by upward movement of
said armature, fluid in the small gap space can flow into the
armature room, and pressure in the small gap space is bled in to
the armature room.
[0018] Therefore, in the course of upward moving of the poppet
valve until it is closed, flowage of fluid from the small gap
through the central hole and slanted holes into the plunger room
increases and rising of pressure in the small gap becomes slower as
the poppet valve moves upward, and rapid pressure drop when the
poppet valve moves down to end fuel injection is evaded and
occurrence of cavitation erosion on the upper surface of the
armature can be prevented.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a longitudinal sectional view of a first
embodiment of the invention of the electromagnetic valve device for
an electromagnetic controlled unit injector for a diesel engine
showing when the poppet valve has been moved up.
[0020] FIG. 2 is a drawing as in FIG. 1 of the first embodiment
when the poppet valve has been moved down.
[0021] FIG. 3 is a longitudinal sectional view of a second
embodiment of the invention of the electromagnetic valve device for
an electromagnetic controlled unit injector for a diesel engine
showing when the poppet valve has been moved up.
[0022] FIG. 4 is a drawing as in FIG. 2 of the second embodiment
when the poppet valve is moving down.
[0023] FIG. 5 is a longitudinal sectional view of the unit injector
for a diesel engine to which the electromagnetic valve device of
the present invention is applied.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] Preferred embodiments of the present invention will now be
detailed with reference to the accompanying drawings. It is
intended, however, that unless particularly specified, dimensions,
materials, relative positions and so forth of the constituent parts
in the embodiments shall be interpreted as illustrative only not as
limitative of the scope of the present invention.
[0025] FIG. 5 is a longitudinal sectional view of the unit injector
for a diesel engine to which the electromagnetic valve device of
the present invention is applied.
[0026] Referring to FIG. 5, in its injector body 1, the unit
injector 100 has a plunger 2 fitted slidably which is reciprocated
by means of a fuel cam not shown in the drawing via a tappet 16 and
a tappet spring 17. Fuel is supplied to a plunger room 3 through a
fuel passage 28 when a poppet valve 4 is opened. When the poppet
valve 4 is closed, fuel in the plunger room 3 is compressed to high
pressure by moving down of the plunger 2 to be sent forth through a
fuel passage 22 toward the fuel pool 21. The high pressure fuel
reached the fuel pool 21 pushes up a needle valve 19 against the
spring load of a needle spring 25. When the needle valve 19 is thus
opened, high pressure fuel in the fuel pool 21 is injected into a
combustion chamber not shown in the drawing through injection holes
20 provided at the apical end part of a nozzle chip 18 to be burned
in the combustion chamber.
[0027] The nozzle chip 18 is held fluid tight to a spring case 26
via a spacer 24 by screw-tightening a nozzle nut 23 to a spring
case 26. The spring case 26 is screw-tightened to the injector body
1 by a fixing nut 27.
[0028] Injection timing of high pressure fuel compressed by the
plunger 2 is controlled by means of an electromagnetic valve device
10.
[0029] In the electromagnetic valve device 10, a solenoid core 11a
having a solenoid coil 11 in it, and a platy armature 12 located in
an armature room 30 below the solenoid core 11a with a small gap 33
from the lower end face of the solenoid core 11a are provided. The
armature 12 is fixed with a fixing screw 35 to the upper end of a
poppet valve 4 which is fit for reciprocation in a through hole of
a valve seat 5. The poppet valve 4 is formed to be a hollow body
having a central hollow 31. A solenoid case 34 covers the solenoid
core 11a.
[0030] A solenoid controller 15 controls energization and
de-enegization of the solenoid coil 11. When the solenoid coil is
energized, the armature 12 is attracted by attraction force
generated by the energization toward the solenoid core 11a to allow
the poppet valve 4 to be seated on a seat face 6 of the valve seat
5 (value of the small gap 33 is C when the poppet valve 4 is
seated). By the seating of the poppet valve 4, a fuel passage 28 to
the plunger room 3 is closed and fuel injection begins.
[0031] When energization of the solenoid coil 11 is shutoff by the
solenoid controller 15, the armature 12 and the poppet valve 4
fixed thereto are pushed down by a poppet valve spring(return
spring) 8, the poppet valve 4 departs from the seat face 6 to open
the fuel passage 28. By the opening of the poppet valve 4, the fuel
passage 28 communicating with the plunger room 3 is communicated
with a fuel spill room 32 (see FIG. 1) and fuel spill port 7
communicating with a fuel passage not shown in the drawing to feed
fuel to the unit injector 100 from a fuel feed pump not shown in
the drawing, pressure in the plunger room 3 decreases rapidly, and
fuel injection ends.
[0032] The present invention relates to the electromagnetic valve
device composed as mentioned above.
The First Embodiment
[0033] FIG. 1 is a longitudinal sectional view of a first
embodiment of the invention of the electromagnetic valve device for
an electromagnetic controlled unit injector for a diesel engine
showing when the poppet valve has been moved up, and FIG. 2 is a
drawing as in FIG. 1 of the first embodiment when the poppet valve
has been moved down.
[0034] Referring to FIGS. 1 and 2, through holes 13 are drilled in
the armature 12 penetrating the armature 12 from the upper surface
12a thereof facing the end surface 11b of the solenoid core 11a to
the rear surface near the outer periphery of the armature 12 such
that distance from the center of the armature to each of the holes
is the same or near the same to each other.
[0035] A flexible thin plate valve 14 and made of stainless steel
or plastic material to have spring function is attached to the rear
surface of the armature 12. The thin plate valve 14 is fixed at its
central part to the rear surface of the armature 12 by the fixing
screw 35 together with the poppet valve 4 so that the central part
is a fixed end and the peripheral part is a free end.
[0036] When the solenoid coil 11 is energized by a signal sent from
the solenoid controller 15 based on engine operating conditions
such as engine rotation speed and engine loads, the armature 12 is
attracted by attraction force generated by the energization toward
the solenoid core 11a to allow the poppet valve 4 to be seated on a
seat face 6 of the valve seat 5 (value of the small gap 33 is C
when the poppet valve 4 is seated) as shown in FIG. 1. When the
poppet valve 4 is seated on the seat face 6, a fuel passage 28 to
the plunger room 3 is closed and fuel injection begins.
[0037] When the armature 12 fixed to the poppet valve 4 moves up,
pressure in the gap 33 between the end surface 11b of the solenoid
core 11a and the upper surface 12a of the armature 12 rises and the
peripheral part of the thin plate valve 14 is bent by the raised
fuel pressure exerting through the holes 13 on the peripheral part
of the thin plate valve 14 as shown in FIG. 1, and the fuel in the
small gap 33 escapes toward the armature room 30 so that pressure
does not rise excessively in the small gap 33. By this, the poppet
valve fixed to the armature can be moved up rapidly.
[0038] In the course of upward moving of the poppet valve 4 until
it is seated on the seat face 6 to close the fuel passage 28,
bending of the thin plate valve 14 increases due to increased
pressure in the small dap 33 and flowage of fluid from the small
gap 33 through the holes 13 increases, so rising of pressure in the
gap 33 becomes slower as the poppet valve 4 moves up.
[0039] When energization of the solenoid coil 11 is shutoff by the
solenoid controller 15 to end fuel injection, the armature 12 fixed
to the poppet valve 4 is pushed down by the poppet valve spring
(return spring) 8 to open the poppet valve 4 as shown in FIG. 2,
pressure in the small gap 33 reduces and the thin plate valve 14
restores its original state to close the holes 13. Therefore, rapid
downward movement of the poppet valve 4 is suppressed and rapid
pressure drop in the small gap 33 is prevented.
[0040] Accordingly, occurrence of cavitation erosion on the surface
of the armature 12 can be prevented, which is experienced in the
prior art.
[0041] In FIGS. 1 and 2, constituent parts the same as those of
FIG. 5 are denoted by the same reference numerals.
The Second Embodiment
[0042] FIG. 3 is a longitudinal sectional view of a second
embodiment of the invention of the electromagnetic valve device for
an electromagnetic controlled unit injector for a diesel engine
showing when the poppet valve has moved up, and FIG. 4 is a drawing
as in FIG. 1 of the first embodiment when the poppet valve has
moved down.
[0043] In the second embodiment, a central through hole 44 and two
outwardly downward slanting holes 41 communicating with the central
hole 44 are provided to the armature 12. The upper end part of the
poppet valve 4 is screwed into the rear side of the armature to be
fixed thereto.
[0044] A check valve 40 is provided at the upper end of the poppet
valve 4 having the central hollow 31.
[0045] The check valve 40 includes a spherical valve body 42 and a
return spring 43 energizing the spherical valve body 42 upward. The
check valve 40 opens and closes the central hole 44 and slanting
holes 41 and also opens and closes the opening of the central
hollow 31 at the upper end of the poppet vale 4. The spherical
valve body 42 of the check valve opens the central hole 44 and
slanting holes 41 when pressure above the upper surface 12a of the
armature 12 rises as mentioned later.
[0046] When the solenoid coil 11 is energized by a signal sent from
the solenoid controller 15 based on engine operating conditions
such as engine rotation speed and engine loads, the armature 12 is
attracted by attraction force generated by the energization toward
the solenoid core 11a to allow the poppet valve 4 to be seated on a
seat face 6 of the valve seat 5 (value of the small gap 33 is C
when the poppet valve 4 is seated) as shown in FIG. 3. When the
poppet valve 4 is seated on the seat face 6 and closes the fuel
passage 28, a fuel passage 28 to the plunger room 3 is closed and
fuel injection begins.
[0047] When the armature 12 fixed to the poppet valve 4 moves up to
close the poppet valve 4, the small gap 33 between the end surface
11b of the solenoid core 11a and the upper surface 12a of the
armature 12 decreases and pressure in the small gap 33 increases,
on the other hand pressure in the space including the central
hollow 31 of the poppet valve 4 and space under the lower end of
the poppet valve 4 increases in volume and decreases in pressure to
negative pressure.
[0048] Therefore, spherical valve body 42 of the check valve 40
provided at the upper end of the poppet valve 4 is pushed down by
the difference between the positive pressure in the small gap 33
and the negative pressure in the central hollow 31 against spring
force of the return spring 42, and the central hole 44 is
opened.
[0049] By this, fluid in the small gap 33 flows through the central
hole 44 and slanted holes 41 into the armature room 30 and pressure
in the small gap 33 is bled in to the armature room 30.
[0050] Therefore, in the course of upward moving of the poppet
valve 4 until it is seated on the seat face 6 to close the fuel
passage 28, flowage of fluid from the small gap 33 through the
holes 44, 41 into the armature room 30 increases and rising of
pressure in the small gap 33 becomes slower as the poppet valve 4
moves upward, and the poppet valve 4 is moved up swiftly without
excessively rapid moving up.
[0051] When energization of the solenoid coil 11 is shutoff by the
solenoid controller 15 to end fuel injection, the armature 12 fixed
to the poppet valve 4 is pushed down by the poppet valve spring 8
to open the poppet valve 4 as shown in FIG. 4, pressure in the
small gap decreases by moving down of the armature 12 and the
spherical valve body 42 of the check valve 40 is pushed upward by
the return spring 43 to close the central hole 44, aided by
positive pressure in the central hollow generated by downward
movement of the poppet valve 4 because the space including the
central hollow and space under the lower end of the poppet valve 4
decreases in volume and increase in pressure. Therefore, rapid
downward movement of the poppet valve 4 is suppressed and rapid
pressure drop in the small gap 33 is prevented.
[0052] Accordingly, occurrence of cavitation erosion on the surface
of the armature 12 can be prevented, which is experienced in the
prior art.
[0053] In FIGS. 3 and 4, constituent parts the same as those of
FIG. 5 are denoted by the same reference numerals.
[0054] According to the first and second embodiments, space for
providing a communicating passage and a check valve is not needed
to be provided in the casing at a side of the armature as is in the
prior art disclosed in the patent literature 1, and the
electromagnetic valve device 10 of compact and requiring less
installation space and having effect mentioned above can be
obtained, by composing such that through holes 13 are provided near
the peripheral part of the platy armature 12 to penetrate the
armature 12 from the upper surface 12a to the rear surface thereof
and the thin plate valve 14 is attached to the rear surface of the
armature 12 to cover the holes 13 in the first embodiment, or the
central hole 44 and slanting holes 41 are formed in the armature 12
and the poppet valve 4 is screwed into the armature 12 at the upper
end part of the poppet valve 4 where the check valve 40 is provided
to open or close the central hole 44 in the second embodiment.
[0055] Further, in the first and second embodiments, it is not
needed to compose such that the outer periphery of the armature
slides contacting to the armature guide surface of the valve body
liquid tight as is in the prior art disclosed in the patent
literature 1, so a large gap is permitted to be provided between
the outer periphery of the armature and the inner surface of the
casing surrounding the armature. Therefore, high machining accuracy
is not needed in machining the outer periphery of the armature and
inner surface of the casing surrounding the armature as is in the
patent literature 1, and machining cost can be reduced.
[0056] While two embodiments of the invention have been illustrated
and described in detail, it is understood that the invention is not
limited thereto and can be applied widely to electromagnetic valve
devices having an armature and a valve body such as a sleeve,
etc.
[0057] According to the invention, when allowing fuel injection to
be begun by a fuel injection apparatus of engine, pressure in the
small gap between the end surface of the solenoid core and the
upper surface of the armature facing the end surface of the
solenoid core increases as the armature is attracted upward to
allow the poppet valve to be closed, the through holes in the
armature near the peripheral part thereof are opened through
bending of the thin plate valve attached to the rear surface of the
armature to cover the holes pushed by the raised pressure in the
small gap exerting on the thin plate valve through the holes, and
the pressure in the small gap is bled in to the armature room.
[0058] Therefore, in the course of upward moving of the poppet
valve until it is closed, bending of the thin plate valve increases
due to increased pressure in the small gap and flowage of fluid
from the small gap through the holes increases, so rising of
pressure in the gap 33 becomes slower as the poppet valve moves up.
When the armature moves down, pressure in the small gap decreases
and the through holes are closed by the thin plate valve, so rapid
downward movement of the armature is prevented, the armature moves
down slowly, and occurrence of cavitation on the upper surface of
the armature is prevented.
[0059] Further, according to the invention, when allowing fuel
injection to be begun by a fuel injection apparatus of engine,
pressure in the small gap between the end surface of the solenoid
core and the upper surface of the armature facing the end surface
of the solenoid core increases as the armature is attracted upward
to allow the poppet valve to be closed, the check valve provided at
the upper end of the poppet valve screwed into the armature opens
the center hole at the top of the poppet valve the raised pressure
in the small gap to allow fluid in the small gap to flow through
the central hole and slanted holes communicating to the center
hole, and pressure in the small gap is bled in to the armature
room.
[0060] Therefore, in the course of upward moving of the poppet
valve until it is closed, flowage of fluid from the small gap
through the central hole and slanted holes into the armature room
increases and rising of pressure in the small gap becomes slower as
the poppet valve moves upward, and rapid pressure drop when the
poppet valve moves down to end fuel injection is evaded and
occurrence of cavitation erosion on the upper surface of the
armature can be prevented.
[0061] In the electromagnetic valve device disclosed in the patent
literature 1, it is necessary to compose such that the clearance
between the periphery of the armature and the inner surface of the
casing is extremely small in order to form a closed space between
the end face of the solenoid core and the face of the armature
facing the end face of the solenoid core at the end of the poppet
valve closing, high machining accuracy is required. On the
contrary, according to the present invention, it is not needed to
form the small gap space to be a closed space, a large clearance is
permitted between the periphery of the armature and the inner
surface of the casing surrounding the armature, high machining
accuracy in not needed, and machining cost is reduced.
[0062] Further, according to the invention, space for providing a
communicating passage and a check valve is not needed to be
provided in the casing at a side of the armature as is in the prior
art disclosed in the patent literature 1, and an electromagnetic
valve device of compact and requiring less installation space and
having effect mentioned above can be obtained, by composing such
that through holes are provided near the peripheral part of the
platy armature to penetrate the armature from the upper surface to
the rear surface thereof and a thin plate valve is attached to the
rear surface of the armature to cover the through holes, or a
central hole and slanting holes communicating to the central hole
are formed in the armature and the poppet valve is screwed into the
armature at the upper end part thereof where a check valve is
provided
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