FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
FUEL INJECTION VALVE;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND
EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED
2
BACKGROUND OF THE INVENTION
Field of the invention
[0001]
The present application relates to a fuel injection
5 valve.
Description of the related art
[0002]
A fuel injection valve including a needle (described as
a valve needle in Patent Literature 1) that is formed of a
10 movable element and a valve closing body, and of a coupling
member, a so-called pipe that couples the movable element and
the valve closing body, and which can move in an axial line
direction, is already commonly known, as disclosed in, for
example, Patent Literature 1.
15 The fuel injection valve disclosed in Patent Literature
1 is such that a vertically long slit is provided in the pipe,
and the slit is such that an aperture width in a valve closing
body side end is formed to be smaller than an aperture width
in a central portion. Further, the movable element and the
20 pipe, and the valve closing body and the coupling member, are
joined by a welded seam.
[0003]
Patent Literature 1: JP-T-2001-504917 (the term “JP-T”
as used herein means a published Japanese translation of a PCT
25 patent application).
3
[0004]
In general, a fuel injection valve is configured that
energization and stop of energization are repeated so that
vertical movement of a needle in a axial direction is repeated,
5 a valve section is opened and closed, and fuel is ejected.
Restriction of a range for the movement of the needle in the
axial direction is executed in a core in upstream of a fuel
flow path, and in a valve sheet provided downstream in
downstream of the fuel flow path. When the needle is in contact
10 with the core or the valve sheet, the contact portion receives
the impact.
[0005]
Although the fuel injection valve disclosed in Patent
Literature 1 is such that the vertically long slit is provided
15 in a tubular pipe, only one vertically long slit is provided,
meaning that when the needle is in contact with a core and a
valve seat, the pipe is compressed and distorted while bending.
When the pipe is compressed, bending stress becomes greatest
in an intermediate portion, there is displacement to a radial
20 direction outer side, and the pipe takes on a barrel form
overall, but as there is no circumferential direction
restriction on the slit, displacement to the radial direction
outer side is at a maximum, because of which an amount of
compression is also at a maximum, and the needle bends to the
25 slit side.
4
[0006]
The needle carries out a reciprocating operation by being
guided by sliding portions in two vertical places, but
clearance of the sliding portion is small, and when the
5 heretofore described kind of bending occurs when a valve
section opens or closes, an outer periphery of the needle and
the sliding portion on an opposite side interfere with each
other, and a large amount of abrasion occurs in both. Due to
this abrasion, for example, a change in an injected amount
10 caused by a mounted engine being used for a long time occurs,
and by extension, becomes a cause of engine trouble.
SUMMARY OF THE INVENTION
[0007]
15 The present application discloses technology for
resolving the heretofore described kind of problem, and has
an object of providing a fuel injection valve such that bending
of a needle occurring when a valve section is opened or closed
is restricted, and abrasion of a sliding portion is reduced.
20 [0008]
A fuel injection valve disclosed in the present
application includes a solenoid device that generates a
magnetic attraction force, a core formed of a tubular magnetic
body at least partially enclosed by the solenoid device, a
25 spring provided in an inner periphery of the core, a tubular
5
holder provided in a lower end of the core, a needle of a
configuration including an armature, which is disposed in an
interior of the holder and is formed of a magnetic material,
a pipe, which is joined to the armature, and a valve section,
5 which is joined to the pipe, and a valve seat that comes into
contact with the valve section, wherein the needle is guided
by a sliding portion of the armature and a sliding portion of
the valve section to move in an axial line direction of the
pipe, and the pipe has a slit, which extends over a whole axial
10 line direction length from an upper end to a lower end in the
axial line direction, and a through hole, which opposes the
slit and extends in the axial line direction.
[0009]
According to the fuel injection valve disclosed in the
15 present application, a fuel injection valve such that bending
of a needle occurring when a valve section is opened or closed
is restricted, and abrasion of a sliding portion is reduced,
is obtained.
20 BRIEF DESCRIPTION OF THE DRAWINGS
[0010]
[Fig. 1] Fig. 1 is a sectional view of a fuel injection
valve according to a first embodiment.
[Fig. 2] Fig. 2 is an enlarged view of an A portion of
25 the fuel injection valve of Fig. 1.
6
[Fig. 3] Fig. 3 is a drawing showing a state of a pipe
configuring the fuel injection valve shown in Fig. 1 before
a roll processing.
[Fig. 4] Fig. 4 is a sectional view of the pipe after
5 the roll processing seen from a direction of a B-B line of Fig.
3.
[Fig. 5] Fig. 5 is a drawing showing a state of a pipe
configuring a fuel injection valve according to a second
embodiment before a roll processing.
10 [Fig. 6] Fig. 6 is a drawing showing a state of a pipe
configuring a fuel injection valve according to a third
embodiment before a roll processing.
[Fig. 7] Fig. 7 is a drawing showing an appearance of
a bending distortion of the pipe when the fuel injection valve
15 according to the third embodiment opens.
[Fig. 8] Fig. 8 is a drawing showing a state of a pipe
configuring a fuel injection valve according to a fourth
embodiment before a roll processing.
[Fig. 9] Fig. 9 is a drawing showing a state of a pipe
20 configuring a fuel injection valve according to a fifth
embodiment before a roll processing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0011]
25 Hereafter, preferred embodiments of a fuel injection
7
valve according to the present application will be described,
using the drawings. In the drawings, identical reference
signs are allotted to identical or similar components, and
sizes or scales of corresponding constituent members are each
5 independent. Although a fuel injection valve configuration
actually includes a further multiple of members, only portions
necessary for the description are shown, and other portions
are omitted, in order to facilitate the description.
[0012]
10 First Embodiment
Fig. 1 is a drawing showing a cross-section of a fuel
injection valve according to a first embodiment, and Fig. 2
is an enlarged view of an A portion of Fig. 1.
In Fig. 1 and Fig. 2, a fuel injection valve 100 supplies
15 fuel to an internal combustion engine utilized as, for example,
an automobile engine. The fuel injection valve 100 includes
a solenoid device 2 that generates a magnetic attraction force
owing to a current being supplied from a drive circuit 1, a
core 3 formed of a tubular magnetic body that is at least
20 partially enclosed by the solenoid device 2, a spring 4 provided
in an inner periphery of the core 3, a tubular holder 5, which
is provided in a lower end of the core 3 and whose end is inserted
between a lower end of an inner periphery of the solenoid device
2 and a lower end of an outer periphery of the core 3, a needle
25 6 provided in an interior of the holder 5, a valve seat 7, and
8
a plate 8 joined to the valve seat 7. The needle 6 is formed
of an armature 61 formed of a magnetic body, a pipe 62 joined
to the armature 61, and a valve section 63 joined to the pipe
62. That is, the pipe 62 is a coupling member of the armature
5 61 and the valve section 63, and the valve section 63 is in
contact with the valve seat 7.
[0013]
The armature 61 and the pipe 62 are joined by, for example,
welding after the pipe 62 is force fitted into the armature
10 61, and the valve section 63 is, for example, welded to the
pipe 62. Also, the core 3 is, for example, welded to the holder
5 after being force fitted into the holder 5. The valve seat
7 is joined to the plate 8, which is positioned on a downstream
side of the valve seat 7, that is, a downstream side of a fuel
15 flow path, and the plate 8 and the holder 5 are, for example,
welded. According to the heretofore described configuration,
the valve seat 7 is fixed to the holder 5.
[0014]
Next, an operation of the needle 6 in the fuel injection
20 valve 100 with the heretofore described configuration will be
described.
When a current is supplied to the solenoid device 2 from
the drive circuit 1, and a magnetic field is generated in the
solenoid device 2, an electromagnetic force acts on the
25 armature 61, and the needle 6 is attracted to the core 3 side.
9
Because of this, the needle 6 is guided by a sliding portion
61a of the armature 61 and a sliding portion 63a of the valve
section 63 to move in an axial line direction. In the present
embodiment, an outer periphery of the armature 61 opposing an
5 inner periphery 5a of the holder 5 forms the sliding portion
61a of the armature 61. Also, an outer periphery of the valve
section 63 opposing an inner periphery 7a of the valve seat
7 forms the sliding portion 63a of the valve section 63. A
limit to which the needle 6 can move in the axial line direction
10 to the core 3 side is a position in which the armature 61 comes
into contact with the core 3.
[0015]
After the supply of current to the solenoid device 2 is
stopped, the needle 6 is guided by the sliding portion 63a of
15 the valve section 63 and the sliding portion 61a of the armature
61 to move in the axial line direction owing to an elastic force
of the spring 4 provided in the interior of the core 3. A limit
to which the needle 6 can move in the axial line direction in
a direction away from the core 3 is a position in which the
20 valve section 63 sits on the valve seat 7.
[0016]
Fig. 3 is a drawing showing a state of the pipe 62
configuring the fuel injection valve 100 before a roll
processing, and Fig. 4 is a sectional view of the pipe 62 after
25 the roll processing seen from a direction of a B-B line of Fig.
10
3.
As shown in Fig. 3 and Fig. 4, the pipe 62 is made by
a roll processing of a rectangular, thin plate 62a that is long
in a horizontal direction. The plate 62a is manufactured from
5 a stainless steel rolled plate having a thickness of in the
region of 0.5mm. A through hole 9 that is long in an extension
direction of a central line of the plate 62a is formed by
pressing on the central line of the plate 62a. A central line
C of the through hole 9 corresponds to the central line of the
10 plate 62a.
[0017]
The through hole 9 is such that an axial line direction
upper end portion is opened across an interval a from an upper
face of the plate 62a, and is opened across an interval b (b
15 ≈ 1mm) from a lower face of the plate 62a. The through hole
9 has a width d (d ≈ 0.3mm), and extends in the central line
C direction, and each of the axial line direction upper end
and the axial line direction lower end is formed in a curved
form R. The plate 62a is subjected to a roll processing until
20 a left end face and a right end face in Fig. 3 are in proximity,
and the left end face and the right end face are opposed across
a slit 9s, forming the pipe 62, which has a C-shaped
cross-section. That is, the slit 9s, which extends over a whole
axial line direction length from the axial line direction upper
25 end to the axial line direction lower end, and whose pipe 62
11
inner diameter side has the width d, is formed in the pipe 62.
[0018]
The pipe 62 is such that an axial line direction upper
end is force fitted into an interior of the armature 61. Force
5 fitting is carried out at a force fitting length of a – b until
an interval between a lower end α of the armature 61 and the
axial line direction upper end of the through hole 9 becomes
b. After the force fitting, the pipe 62 and the lower end α
of the armature 61 are joined by, for example, welding. Next,
10 the valve section 63 is brought into contact with and held
against an axial line direction lower end of the pipe 62, and
the valve section 63 is joined by, for example, welding to the
axial line direction lower end of the pipe 62. Upper and lower
welded portions of the pipe 62 are across the interval b from
15 the axial line direction upper and lower ends of the through
hole 9, and the interval b is set to be a length approximately
two times a thickness of the pipe 62. Because of this,
distortion caused by the pressing of the through hole 9 is
restricted at the upper and lower welded portions of the pipe
20 62, the plate 62a has good roundness even when in a pipe state
after the roll processing, a state of contact between the
armature 61 and the valve section 63 is maintained over a whole
periphery, and a high-strength welding can be carried out.
[0019]
25 The fuel injection valve 100 according to the first
12
embodiment is configured as heretofore described, meaning that
when current is supplied to the fuel injection valve 100 having
the needle 6, the needle 6 is such that an upper end face of
the armature 61 collides with a lower end face of the core 3,
5 and an open valve state is reached. As the needle 6 is
configured of the armature 61 and the valve section 63, which
have high rigidity and mass, and the pipe 62, which has low
rigidity and mass, the needle 6 is of a so-called spring-mass
system structure wherein the armature 61 and the valve section
10 63, which are mass points, are joined above and below the pipe
62, which is a spring in mechanical terms. A momentum mv (a
physical quantity wherein velocity v is multiplied by mass m)
of the needle 6 when a valve opening collision occurs is
converted into an impulse Ft (a physical quantity wherein a
15 reactive force F received from the core 3 is multiplied by a
time t for which the reactive force F is received) received
by an end face of the armature 61, and the needle 6 becomes
stationary. A momentum of the valve section 63 is transmitted
to the armature 61 together with a delay due to distortion of
20 the pipe 62, because of which the time t increases, and a
repulsive force decreases. In order to restrict abrasion of
the armature 61 by weakening the repulsive force, it is
sufficient to reduce the rigidity of the pipe 62.
[0020]
25 When a valve opening collision occurs, the momentum of
13
the valve section 63 is received in the pipe 62, and a
compressive load acts from the axial line direction lower end.
A cylindrical thin portion of the pipe 62 that receives the
compressive load increases in diameter to an outer periphery
5 side, and an intermediate portion, wherein bending stress is
at a maximum, is displaced to a maximum in a radial outer side
direction, because of which there is distortion into a barrel
form.
[0021]
10 A magnitude of the increase in diameter of the
intermediate portion of the pipe 62 is at a maximum in the slit
9s, which has no circumferential direction restriction, but
as the diameter also attempts to increase in a portion of the
through hole 9, the increase in diameter is well balanced, and
15 there is well-balanced compression in accordance with the
magnitude of the increase in diameter, because of which a state
wherein bending of the pipe 62 is also restricted can be
achieved, which leads to a restriction of sliding portion
abrasion when the valve opens. Heretofore, a description has
20 been given for when the valve opens, but the same also applies
when the valve closes.
[0022]
Second Embodiment
Next, a fuel injection valve according to a second
25 embodiment will be described.
14
Fig. 5 is a drawing showing a state of a pipe configuring
the fuel injection valve according to the second embodiment
before a roll processing.
In Fig. 5, in addition to the through hole 9, there is
5 one second through hole 9a on either side of the through hole
9 in the plate 62a configuring the pipe 62. The second through
holes 9a are formed to have bilateral symmetry with respect
to the through hole 9 axial line direction on either side of
the through hole 9. Also, the second through hole 9a is formed
10 in a position midway between the slit 9s formed in the C-shaped
pipe 62 (refer to Fig. 4) and the through hole 9, and extends
with the width d (d ≈ 0.3mm) in a direction the same as the
through hole 9 axial line direction, and each of an axial line
direction upper end and an axial line direction lower end is
15 formed in a curved form R. As other configurations are the
same as in the first embodiment, an illustration thereof is
omitted from the drawings.
[0023]
The fuel injection valve according to the second
20 embodiment configured in this way is such that when a valve
opening collision occurs, the momentum of the valve section
63 is received in the pipe 62, and a compressive load acts from
the axial line direction lower end. The cylindrical thin
portion of the pipe 62 that receives the compressive load
25 increases in diameter to the outer periphery side, and the
15
intermediate portion, wherein bending stress is at a maximum,
is displaced to a maximum in the radial outer side direction,
because of which there is distortion into a barrel form.
[0024]
5 The magnitude of the increase in diameter of the
intermediate portion of the pipe 62 is at a maximum in the slit
9s, which has no circumferential direction restriction, but
as there is also no circumferential direction restriction in
a portion of the through hole 9 on the opposite side, the
10 diameter attempts to increase to an extent near that of the
slit 9s, because of which the increase in diameter is well
balanced left and right, and there is well-balanced compression
in accordance with the magnitude of the increase in diameter.
Consequently, a state wherein bending of the pipe 62 is also
15 restricted more in comparison with a case wherein there is no
second through hole 9a is achieved, and furthermore, owing to
the second through hole 9a being formed, bending distortion
of the pipe 62 increases, and rigidity is lowered, which leads
to a restriction of colliding portion abrasion when the valve
20 opens or closes.
[0025]
Third Embodiment
Next, a fuel injection valve according to a third
embodiment will be described.
25 Fig. 6 is a drawing showing a state of a pipe configuring
16
the fuel injection valve according to the third embodiment
before a roll processing.
In Fig. 6, in addition to the through hole 9, a third
through hole 11a, which has an axial line perpendicular to the
5 axial line of the through hole 9 and which is long in a horizontal
direction that intersects the through hole 9, is formed in the
plate 62a configuring the pipe 62. Also, a second slit 11b
that is across a gap from the third through hole 11a and is
long in the horizontal direction, that is, that has an axial
10 line the same as the axial line of the third through hole 11a,
is formed on both left and right end sides of the third through
hole 11a. The second slits 11b are opened one each in the left
end face and the right end face of the plate 62a, that is, in
the slit 9s. Furthermore, fourth through holes 11c that are
15 formed across a gap from the through hole 9, have bilateral
symmetry with respect to the through hole 9, are long in the
horizontal direction, and have an axial line that is
perpendicular to the axial line of the through hole 9, are
formed above the third through hole 11a and the second slit
20 11b.
[0026]
Herein, a first layer is configured of the two fourth
through holes 11c, and a second layer is configured of the third
through hole 11a and the two second slits 11b. A width e of
25 the third through hole 11a, the two second slits 11b, and the
17
two fourth through holes 11c is formed in such a way that e
≈ 0.4mm. Also, an interval f between the first layer and the
second layer is formed in such a way that f ≈ 0.8mm. Further,
the through hole 9 is opened from the first layer to the second
5 layer. As other configurations are the same as in the first
or second embodiment, an illustration thereof is omitted from
the drawings.
[0027]
The fuel injection valve according to the third
10 embodiment configured in this way is such that when a valve
opening collision occurs, the momentum of the valve section
63 is received in the pipe 62, and a compressive load acts from
the axial line direction lower end. A load received by a
downstream side of the pipe 62 is applied to a central portion
15 of a thick portion 12a formed between the first layer and the
second layer via a thick portion 12b formed between the third
through hole 11a and the second slit 11b configuring the second
layer, as shown in Figs. 7(a) and (b).
[0028]
20 The thick portion 12a is in a state wherein the two ends
are supported one each by two thick portions of the first layer,
and a load is applied to a center of a doubly-supported beam,
because of which bending distortion occurs, and rigidity
decreases, which leads to a restriction of colliding portion
25 abrasion when the valve opens or closes.
18
[0029]
The two left and right doubly-supported beams are
disposed in an independent state wherein the slit 9s and the
through hole 9 are neighboring on both sides of each and there
5 is no horizontal direction restriction, and distortion in the
horizontal direction when a compressive load is applied is not
restricted, because of which the amount of distortion is large,
and the distortion has good left-right balance.
[0030]
10 Fourth Embodiment
Next, a fuel injection valve according to a fourth
embodiment will be described.
Fig. 8 is a drawing showing a state of a pipe configuring
the fuel injection valve according to the fourth embodiment
15 before a roll processing.
In Fig. 8, in addition to the through hole 9, the third
through hole 11a and the second slit 11b, which is across a
gap from the third through hole 11a and is long in the horizontal
direction on both left and right end sides of the third through
20 hole 11a, are formed in the plate 62a configuring the pipe 62.
A fifth through hole 11d that is long in the horizontal
direction and a third slit 11e, which is across a gap from the
fifth through hole 11d and is long in the horizontal direction
on both sides of the fifth through hole 11d, are formed in a
25 central portion on an axial direction upper end side of the
19
through hole 9. A first layer is configured of the fifth
through hole 11d and the third slit 11e, and a second layer
across the interval f is configured below the first layer,
wherein the second layer has bilateral symmetry with respect
5 to the through hole 9, and is formed by the fourth through hole
11c, which is across a gap from the through hole 9 and is long
in the horizontal direction.
[0031]
Furthermore, a third layer formed of the third through
10 hole 11a and the second slit 11b, which is across the interval
f and is of the same form as the first layer, is configured
below the second layer. Further, the width e of the fifth
through hole 11d and the two third slits 11e forming the first
layer, the two fourth through holes 11c forming the second layer,
15 and the third through hole 11a and the two second slits 11b
forming the third layer, is formed in such a way that e ≈ 0.4mm.
Also, the interval f between the first layer and the second
layer and the interval f between the second layer and the third
layer are formed in such a way that f ≈ 0.8mm. Further, the
20 through hole 9 is opened from the first layer to the third layer.
As other configurations are the same as in the first, second,
or third embodiment, an illustration thereof is omitted from
the drawings.
[0032]
25 The fuel injection valve according to the fourth
20
embodiment configured in this way is such that when a valve
opening collision occurs, the pipe 62 receives the momentum
of the valve section 63, and a compressive load acts from the
axial line direction lower end. A load received by the
5 downstream side of the pipe 62 is applied to the central portion
of the thick portion 12a formed between the second layer and
the third layer via the thick portion 12b formed between the
third through hole 11a and the second slit 11b configuring the
third layer.
10 [0033]
The thick portion 12a is in a state wherein the two ends
are supported one each by two thick portions of the second layer,
and a load is applied to the center of a doubly-supported beam.
Furthermore, the thick portion 12b of the third layer is
15 connected to both ends of a thick portion 12c formed between
the first layer and the second layer, and the thick portion
12c is supported by a thick portion of the first layer, and
is in a state wherein a load receives a center of a
doubly-supported beam. Because of this, a form is such that
20 two doubly-supported beams are disposed in series, distortion
increases with respect to the third embodiment, and furthermore,
rigidity decreases, which leads to a restriction of colliding
portion abrasion when the valve opens or closes.
[0034]
25 The two left and right doubly-supported beams disposed
21
in series are disposed in an independent state wherein the slit
9s and the through hole 9 are neighboring on both sides of each
and there is no horizontal direction restriction, and
distortion in the horizontal direction when a compressive load
5 is applied is not restricted, because of which the amount of
distortion is large, and the distortion has good left-right
balance.
[0035]
Fifth Embodiment
10 Next, a fuel injection valve according to a fifth
embodiment will be described.
Fig. 9 is a drawing showing a state of a pipe configuring
the fuel injection valve according to the fifth embodiment
before a roll processing.
15 In Fig. 9, in the plate 62a configuring the pipe 62, taking
a position of the axial line direction upper end of the through
hole 9 to be farther to the core 3 side than the welded portion
of the armature 61 and the pipe 62, that is, the lower end α
of the armature 61, the through hole 9 is formed to a length
20 that crosses the lower end α of the armature 61, which is the
welded portion. As other configurations are the same as in
the first embodiment, an illustration thereof is omitted from
the drawings.
[0036]
25 As the fuel injection valve according to the fifth
22
embodiment is configured as heretofore described, the armature
61 and the pipe 62 are joined by a laser welding of the lower
end of the armature 61 and the welded portion of the pipe 62.
The welded portions subjected to dot-formed laser irradiation
5 fuse, and the two metals mix, but contraction occurs due to
solidifying cooling after the laser irradiation is finished,
and the armature 61 is drawn to the welded portion and distorts
into a curve. The laser irradiation rotates once around a
circumference of a boundary portion between the two owing to
10 a rotation of the needle 6, whereby welding around the whole
circumference is completed.
Although the heretofore described curving distortion
occurs in each of dot-form welded portions, the same kind of
distortion also occurs on the opposing side of an axis owing
15 to the whole-circumference welding, with the result that the
curving distortion of the armature 61 is restricted.
[0037]
In the present embodiment, the slit 9s is formed in the
pipe 62, and the through hole 9 is formed on the opposing side
20 across a central axis of the slit 9s and the pipe 62, because
of which the armature 61 and the pipe 62 are welded in equal
portions excepting the slit 9s and the through hole 9, meaning
that curving distortion of the pipe 62 can be prevented, and
the needle 6 with little bending can be obtained. Because of
25 this, sliding portion abrasion caused by a sliding operation
23
is restricted, and a flowrate change caused by long-term use
can be prevented.
[0038]
Although the present application is described above in
5 terms of various exemplifying embodiments and implementations,
it should be understood that the various features, aspects,
and functions described in one or more of the individual
embodiments are not limited in their applicability to the
particular embodiment with which they are described, but
10 instead can be applied, alone or in various combinations, to
one or more other embodiments.
It is therefore understood that numerous modifications
that have not been exemplified can be devised without departing
from the scope of the present application. For example, at
15 least one constituent component may be modified, added, or
eliminated. At least one of the constituent components
mentioned in at least one of the preferred embodiments may be
selected and combined with the constituent components
mentioned in another preferred embodiment.
20 Reference Signs List
[0039]
1 drive circuit, 2 solenoid device, 3 core, 4 spring, 5 holder,
5a inner periphery, 6 needle, 61 armature, 61a sliding portion,
62 pipe, 62a plate, 63 valve section, 63a sliding portion, 7
25 valve seat, 7a inner periphery, 8 plate, 9 through hole, 9a
24
second through hole, 9s slit, 11a third through hole, 11b second
slit, 11c fourth through hole, 11d fifth through hole, 11e third
slit, 12a, 12b, 12c thick portion, 100 fuel injection valve,
R curved form, α lower end.
5
25
We Claim:
[Claim 1]
A fuel injection valve, comprising:
5 a solenoid device that generates a magnetic attraction
force;
a core formed of a tubular magnetic body at least
partially enclosed by the solenoid device;
a spring provided in an inner periphery of the core;
10 a tubular holder provided in a lower end of the core;
a needle of a configuration including an armature, which
is disposed in an interior of the holder and is formed of a
magnetic material, a pipe, which is joined to the armature,
and a valve section, which is joined to the pipe; and
15 a valve seat that comes into contact with the valve
section, wherein
the needle is guided by a sliding portion of the armature
and a sliding portion of the valve section to move in an axial
line direction of the pipe, and
20 the pipe has a slit, which extends over a whole axial
line direction length from an upper end to a lower end in the
axial line direction, and a through hole, which opposes the
slit and extends in the axial line direction.
25
26
[Claim 2]
The fuel injection valve according to claim 1, wherein
the pipe has a second through hole extending in the axial line
direction of the pipe between the through hole and the slit.
5 [Claim 3]
The fuel injection valve according to claim 2, wherein
the second through hole is formed on both sides of the through
hole in such a way as to have symmetry with respect to an axial
line of the through hole.
10 [Claim 4]
The fuel injection valve according to claim 1, wherein
the pipe has a third through hole, which has an axial line
perpendicular to an axial line of the through hole and
intersects the through hole,
15 a second slit, which has an axial line the same as that
of the third through hole, is across a gap from the third through
hole on both sides of the third through hole, and is opened
in the slit, and
a fourth through hole, which has an axial line
20 perpendicular to the axial line of the through hole and is
formed across a gap from the through hole on both sides of the
through hole.

[Claim 5]
The fuel injection valve according to any one of claims
1 to 4, wherein the pipe and the armature are joined by welding,
and the through hole is formed to a length that crosses a welded
5 portion of the pipe and the armature.