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 100-8310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

2
DESCRIPTION
TECHNICAL FIELD
5 [0001] The present disclosure relates to a fuel injection
valve.
BACKGROUND ART
[0002] As background art in this technical field, for
10 example, the fuel injection valve described in Patent
Document 1 is known. In Patent Document 1, an elastic
portion is provided at an intermediate portion of a tubular
body 36 connecting an armature 12 and a valve portion 14 of a
valve body. The tubular body 36 shown in FIG. 5 is produced
15 by rolling a flat plate.
[0003] In a development view thereof, rectangular opening
portions each of which is the elastic portion are formed so
as to be longer in an axial direction (vertical direction in
FIG. 5) than in a circumferential direction (horizontal
20 direction in FIG. 5). In the development view of the tubular
body 36 of FIG. 5, when a portion in which the opening
portions are arranged in the circumferential direction is
regarded as one layer, a cutout layer 20 in which a through
hole and a cutout are open, and a penetration layer 19 in
25 which only a through hole is open are present. The cutout
3
layer 20 and the penetration layer 19 are arranged
alternately in the axial direction, and the opening portions
of the respective layers are formed so as to be displaced
relative to each other in the circumferential direction by
5 1/2 of the pitch of the opening portions.
[0004] Therefore, plate portions between the opening
portions of the layers are circumferential plate portions
(circumferential webs) extending in the circumferential
direction, and the layers are connected to each other via the
10 circumferential webs.
[0005] Owing to such a configuration, the load received by
the valve portion 14 from a valve seat 8 immediately after
the fuel injection valve becomes closed to cause collision is
transmitted to the tubular body 36, and each circumferential
15 web receives the load in the axial direction at both ends
thereof and becomes deformed in a bending manner, whereby the
tubular body 36 behaves like a compression spring to absorb
the collision load. Accordingly, the operating sound is
reduced.
20
CITATION LIST
PATENT DOCUMENT
[0006] Patent Document 1: Japanese Laid-Open Patent
Publication No. 2-195084
25
4
SUMMARY OF THE INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION
[0007] The load received by the valve portion 14 from the
valve seat 8 immediately after the fuel injection valve is
5 closed is transmitted to the tubular body 36. When the
circumferential web becomes deformed in a bending manner due
to the load, since the cross-sectional shape of the tubular
body 36 is a C shape and is not point-symmetrical, an
imbalance occurs in rigidity, so that the valve body falls in
10 the direction toward the low-rigidity portion. In the
phenomenon in the axial direction of the valve body, the
valve body is bent in a predetermined direction at the lowrigidity cutout layer 20 of the tubular body 36, and the
armature 12 and the inner peripheral surface of a holder 39
15 interfere with each other when the bending becomes large.
[0008] The tubular body 36 of Patent Document 1 has a
plurality of cutout layers 20, and the bending angle
increases according to the number of layers. In addition,
the elastic portion is long in the axial direction, and the
20 cutout layers 20 are present at a position where the distance
from the armature 12 is relatively long, so that the amount
of deflection of the armature 12 due to the bending of the
cutout layers 20 is relatively large. When the armature 12
deflects greatly and the interference with the inner
25 peripheral surface of the holder 39 increases, the frictional
5
resistance therebetween increases and the elastic deformation
of the tubular body 36 is significantly hindered. As a
result, the absorption of the collision load when the valve
is closed becomes insufficient, and the operating sound is
5 not significantly reduced.
[0009] A similar problem arises when the valve is opened,
and the load received by the armature 12 immediately after
the valve body collides with a core 1 is transmitted to the
tubular body 36, and bending occurs at the cutout layers 20.
10 Due to the large deflection of the valve portion 14 due to
this bending and the interference with the inner periphery of
the valve seat 8 due to this, the frictional resistance
increases, and the elastic deformation of the tubular body is
significantly hindered. As a result, the absorption of the
15 collision load when the valve is opened becomes insufficient,
and the operating sound is not significantly reduced.
[0010] A particular problem is that when the clearance of
an armature sliding portion or a valve portion sliding
clearance is small, there is little margin for the above20 mentioned interference, so that strong interference with the
mating part occurs due to deflection, and the operating sound
is not reduced.
[0011] The present disclosure has been made in
consideration of the above circumstances, and an object of
25 the present disclosure is to optimize the dimensions and
6
position of an elastic portion of a tubular body, thereby
avoiding or appropriately adjusting interference of an
armature and a valve portion with mating parts when a valve
is closed and when the valve is opened, and reducing the
5 operating sound when the valve is closed and when the valve
is opened.
SOLUTION TO THE PROBLEMS
[0012] A fuel injection valve according to the present
10 disclosure is a fuel injection valve in which a valve body
having an armature made of a magnetic material, a tubular
body connected to the armature, and a valve portion connected
to the tubular body slides in an axial direction inside a
holder by a magnetic attraction force generated by a solenoid
15 device, wherein a cross-section of the tubular body has a C
shape, the tubular body includes an elastic portion having an
opening formed so as to be shorter in the axial direction
than in a circumferential direction, in an intermediate
portion in the axial direction of the tubular body, a
20 clearance between the armature and an armature sliding
portion serving as a guide during sliding is set to be larger
than a clearance between the valve portion and a valve
portion sliding portion serving as a guide during sliding,
and a distance from the elastic portion to the armature
7
sliding portion is longer than a distance from the elastic
portion to the valve portion sliding portion.
EFFECT OF THE INVENTION
5 [0013] In the fuel injection valve according to the
present disclosure, by setting the clearance of the armature
sliding portion to be larger than the clearance of the valve
portion sliding portion, the margin for interference due to
falling of the armature when the valve is closed is made
10 larger than the margin for the falling of the valve body when
the valve is opened. Furthermore, by making the distance
from the elastic portion to the armature sliding portion
longer than the distance from the elastic portion to the
valve portion sliding portion, the amount of deflection of
15 the armature when the valve is opened/closed is made larger
than the amount of deflection of the valve body. Owing to
such a configuration, inhibition of the elastic deformation
of the tubular body by the frictional resistance due to
interference with the armature or the valve portion is
20 prevented as much as possible when the valve is
opened/closed, whereby reduction of the operating sound by
absorption of the collision load when the valve is
opened/closed is achieved.
25 BRIEF DESCRIPTION OF THE DRAWINGS
8
[0014] [FIG. 1] FIG. 1 is a cross-sectional view showing
the configuration of a fuel injection valve according to
Embodiment 1.
[FIG. 2] FIG. 2 is an enlarged view of a portion A
5 of the fuel injection valve in FIG. 1.
[FIG. 3] FIG. 3 is a diagram showing an example
before rolling of a tubular body in FIG. 1.
[FIG. 4] FIG. 4 is a cross-sectional view taken
along a line X-X in FIG. 3 when being rolled.
10 [FIG. 5] FIG. 5 is a diagram showing an example
before rolling of a tubular body having a penetration layer.
[FIG. 6] FIG. 6 is a diagram showing an example
before rolling of a tubular body in the case of welding an
armature, the tubular body, and a valve portion.
15
DESCRIPTION OF EMBODIMENTS
[0015] Hereinafter, preferred embodiments of the power
control device according to the present disclosure will be
described with reference to the drawings. It is noted that
20 the same components and corresponding parts are denoted by
the same reference characters, and the detailed description
thereof is omitted. Similarly, also in the subsequent
embodiments, the redundant description of the components
denoted by the same reference characters is omitted.
25 [0016] Embodiment 1
9
FIG. 1 is a cross-sectional view showing the
configuration of a fuel injection valve 1 according to
Embodiment 1, FIG. 2 is an enlarged view of a portion A in
FIG. 1 and is a diagram showing the positional relationship
5 between a holder 5, a valve body, and a valve seat 7, and
FIG. 3 is a development view before rolling of a tubular body
62 shown in FIG. 1 and shows the state of a cutout layer 10.
[0017] In FIG. 1, main components of the fuel injection
valve 1 are a solenoid device 2 which is supplied with a
10 current from the outside and generates a magnetic attraction
force, a core 3 which is provided inside the solenoid device
2 and made of a magnetic material, a spring 4 which is
disposed inside the core 3, the holder 5 which is disposed on
the inner periphery of the solenoid device 2, a valve body 6
15 which is disposed inside the holder 5, an armature 61 which
is a component of the valve body 6 and made of a magnetic
material, the tubular body 62 which is connected to the
armature 61, a valve portion 63 which is connected to the
tubular body 62, the valve seat 7 which comes into contact
20 with the valve portion 63, and a plate 8 which is connected
to the valve seat 7.
[0018] Next, the valve body 6 will be described. The
armature 61 is press-fitted into the tubular body 62 and then
connected thereto by welding. The valve portion 63 is also
25 welded to the tubular body 62. The core 3 is press-fitted
10
into the holder 5 and then welded thereto. The valve seat 7
is connected to the plate 8 located on the downstream side,
and the valve seat 7 is fixed by welding the plate 8 and the
holder 5.
5 [0019] Next, operation of the valve body 6 will be
described. When the solenoid device 2 is energized and a
magnetic field is generated, an electromagnetic force acts on
the armature 61 and the valve body 6 is attracted to the core
3 side. As shown in FIG. 2, the valve body 6 moves in the
10 axial direction while being guided by an armature sliding
portion 61a and a valve portion sliding portion 63a. In the
present embodiment, an outer peripheral portion of the
armature 61 that faces an inner periphery (holder inner
peripheral surface) 5a of the holder 5 is the armature
15 sliding portion 61a. In addition, an outer peripheral
portion of the valve portion 63 that faces an inner periphery
(valve seat inner peripheral surface 7a) of the valve seat 7
is the valve portion sliding portion 63a. The limit of
movement of the valve body 6 in the axial direction toward
20 the core side is the position at which the armature 61 comes
into contact with the core 3.
[0020] After the energization of the solenoid device 2 is
stopped, the valve body 6 moves in the axial direction, while
being guided by the valve portion sliding portion 63a, by the
25 elastic force of the spring 4 provided inside the core 3.
11
The limit of movement of the valve body 6 in the axial
direction toward the side away from the core 3 is the
position at which the valve portion 63 sits on the valve seat
7.
5 [0021] The tubular body 62 is obtained by rolling a
stainless steel flat plate and has a C-shaped cross section,
and, as shown in FIG. 3, the developed shape of the tubular
body 62 has an elastic portion having openings formed so as
to be shorter in the axial direction than in the
10 circumferential direction, in an intermediate portion in the
axial direction. The elastic portion is a cutout layer 10 in
which one through hole 10a and two cutouts 10b are open, and
an axial plate portion (axial web) 12a elastically connects
an upper portion and a lower portion of the elastic portion
15 between the through hole 10a and each cutout 10b.
[0022] The width of each axial web 12a is twice the plate
thickness thereof. This contributes to the improvement of
the compressive elasticity of the axial web 12a as the
minimum width that allows favorable processing in which a
20 flat portion around each opening is less deformed during
pressing. The lengths in the axial direction of the opened
through hole 10a and cutouts 10b are made equal to the plate
thickness. This contributes to minimizing the length in the
axial direction of the elastic portion as the minimum length
25 that ensures a relatively long life of a punch during
12
pressing and can achieve good processability for mass
production.
[0023] The load received by the valve portion 63 from the
valve seat 7 immediately after the fuel injection valve 1
5 becomes closed to cause collision is transmitted to the
tubular body 62. Then, each axial web 12a receives the load
in the axial direction at both ends thereof and becomes
deformed in a compressive manner, so that the tubular body 62
behaves like a compression spring to absorb the collision
10 load.
[0024] As shown in FIG. 4, the cross-section of the cutout
layer 10 of the tubular body 62 has a C shape and the
arrangement of the axial webs 12a is not point-symmetrical,
so that the rigidity with respect to the compressing load is
15 uneven. Accordingly, when a load in the axial direction is
applied to the tubular body 62 when the valve is closed,
stress is not applied line-symmetrically and the amount of
compression is increased in the direction toward the lowrigidity portion. In the valve body 6, bending occurs at the
20 cutout layer 10 of the tubular body 62, and the armature 61
falls.
[0025] A similar phenomenon also occurs immediately after
the fuel injection valve 1 becomes opened to cause collision.
In the valve body 6, bending occurs at the cutout layer 10 of
25 the tubular body 62, and the valve portion 63 falls. When
13
the amount of bending of the tubular body 62 becomes large,
the armature 61 comes into contact with the holder inner
peripheral surface 5a, and the valve portion 63 comes into
contact with the valve seat inner peripheral surface 7a and
5 receives frictional resistance, thereby inhibiting elastic
deformation in the axial direction of the tubular body 62.
[0026] Meanwhile, as shown in FIG. 2, a clearance C1 of
the armature sliding portion 61a which is the margin for
interference due to the falling of the armature 61 is set to
10 C1 > C2 with respect to a clearance C2 of the valve portion
sliding portion 63a which is the margin for interference due
to the falling of the valve portion 63.
[0027] The elastic portion of the tubular body 62 is
formed so as to be relatively short in the axial direction.
15 As shown in FIG. 2, a distance L1 from the elastic portion to
the armature sliding portion 61a and a distance L2 from the
elastic portion to the valve portion sliding portion 63a are
uniquely defined, so that mass production control can be
facilitated. The amount of falling of the armature 61 when
20 the valve is closed is proportional to the distance L1, the
amount of falling of the valve portion 63 when the valve is
opened is proportional to the distance L2, and L1 > L2 is set.
Since the magnitude of the amount of falling is adjusted so
as to correspond to the magnitude of the margin for
25 interference, excessive interference of the armature 61 or
14
the valve portion 63 is prevented. Furthermore, the
operating sound is reduced.
[0028] By setting the clearances to C1 > C2 as described
above, the margin for interference due to the falling of the
5 armature 61 when the valve is closed is made larger than the
margin for the falling of the valve body 6 when the valve is
opened. In addition, the length in the axial direction of
the elastic portion formed in the tubular body 62 is made
relatively short, and the bent potion when the valve is
10 opened/closed is defined substantially at one location in the
axial direction. Furthermore, by setting the position of the
elastic portion such that distance L1 > distance L2 is
satisfied, the amount of deflection of the armature 61 when
the valve is opened/closed is made larger than the amount of
15 deflection of the valve body 6. Owing to these facts, when
the valve is opened/closed, the armature 61 or the valve body
6 is prevented from interfering with a mating part, for
example, the holder inner peripheral surface 5a or the valve
seat inner peripheral surface 7a. Alternatively, the amount
20 of interference is appropriately adjusted such that either
one of the armature 61 and the valve portion 63 does not
excessively interfere with the mating part, and inhibition of
the elastic deformation of the tubular body 62 by the
frictional resistance due to interference is prevented as
25 much as possible, thereby achieving reduction of the
15
operating sound by absorption of the collision load when the
valve is opened/closed.
[0029] Moreover, the cutout layer 10 is formed in the
intermediate portion of the tubular body 62, and the upper
5 portion and the lower portion of the cutout layer 10 are
connected to each other via the axial webs 12a. Owing to
such a configuration, the load received by the valve portion
63 from the valve seat immediately after the fuel injection
valve becomes closed to cause collision is transmitted to the
10 tubular body 62, and each axial web 12a receives the load in
the axial direction at the upper and lower ends thereof and
becomes deformed in a compressive manner, whereby the tubular
body 62 behaves like a compression spring to absorb the
collision load. By forming the elastic portion as the cutout
15 layer 10 formed only in the intermediate portion, the elastic
portion can be formed in a relatively simple shape, and the
production control for the distance L1 and the distance L2
can also be facilitated.
[0030] In the above-described embodiment, as the elastic
20 portion, the cutout layer 10, which has one through hole 10a
and two cutouts 10b shorter in the axial direction than in
the circumferential direction, and axial webs 12a between
these openings, is formed over the axial periphery of the
intermediate portion in the axial direction of the tubular
16
body 62, but the number of openings included in the cutout
layer 10 is not limited thereto.
[0031] Embodiment 2
FIG. 5 is a diagram showing a state before rolling
5 of a tubular body 62 different from that in Embodiment 1. In
FIG. 5, an elastic portion of the tubular body 62 includes a
cutout layer 10, and a penetration layer 11 having two
through holes 10a and provided on the downstream side of the
cutout layer 10 with a circumferential plate portion
10 (circumferential web) 12b therebetween.
[0032] The width of the circumferential web 12b is twice
the plate thickness thereof. This contributes to the
improvement of the bending elasticity of the circumferential
web 12b as the minimum width that allows favorable processing
15 in which a flat portion around each opening is less deformed
during pressing. The openings formed in the cutout layer 10
and the penetration layer 11 are arranged so as to be
displaced relative to each other by 1/2 of the pitch of the
openings in the circumferential direction of the tubular body
20 62, and the length in the circumferential direction of the
circumferential web 12b is made uniform. The cutout layer 10
and the penetration layer 11 are connected to each other via
the circumferential web 12b, and the upper portion and the
lower portion of the elastic portion are elastically
25 connected to each other by two axial webs 12a and the one
17
circumferential web 12b. Owing to such a configuration,
elastic deformation is more easily caused than in Embodiment
1, and the operating sound reducing effect is further
enhanced.
5 [0033] As described above, in Embodiment 2, the cutout
layer 10 and the penetration layer 11 are connected to each
other via the circumferential web 12b. The load received by
the valve portion 63 from the valve seat immediately after
the fuel injection valve becomes closed to cause collision is
10 transmitted to the tubular body 62, and the circumferential
web 12b receives the load in the axial direction at both ends
thereof and becomes deformed in a bending manner, whereby the
tubular body 62 behaves like a compression spring to absorb
the collision load. Owing to the configuration of the
15 circumferential web 12b and the axial webs 12a, elastic
deformation is easily caused.
[0034] Embodiment 3
FIG. 6 is a diagram showing an example of a state
before rolling of a tubular body 62 in the case of welding
20 the armature 61 and the valve portion 63 to the tubular body
62.
Since welding is performed above and below the
tubular body 62 in the axial direction, if the cutout layer
10 is disposed on each welding side of the tubular body 62, a
25 heat dissipation path for heat generated during welding is
18
blocked by the cutout, resulting in high heat, whereby
deformation or spatter may occur. In the present embodiment,
as shown in FIG. 6, the penetration layer 11 is disposed on
each welding side, so that the heat during welding of the
5 armature 61 and the tubular body 62 is dissipated from the
axial webs 12a of the penetration layer 11 located on the
welding side. The number of axial webs 12a in the
penetration layer 11 is larger than that in the cutout layer
10, and thus the penetration layer 11 has improved heat
10 dissipation. In particular, there is a concern about heat
dissipation at each end of the C shape. However, since the
axial web 12a is disposed at this portion in the penetration
layer 11, heat dissipation is ensured. Owing to these facts,
occurrence of deformation and spatter due to high heat during
15 welding can be prevented.
[0035] Owing to such a configuration, the heat during
welding of the armature 61 and the tubular body 62 is
dissipated from the axial webs 12a of the penetration layer
11 located on the welding side. These contents achieve the
20 same advantageous effects even when the valve portion 63 and
the tubular body 62 are welded.
[0036] Although the disclosure is described above in terms
of various exemplary embodiments and implementations, it
should be understood that the various features, aspects, and
25 functionality described in one or more of the individual
19
embodiments are not limited in their applicability to the
particular embodiment with which they are described, but
instead can be applied, alone or in various combinations to
one or more of the embodiments of the disclosure.
5 It is therefore understood that numerous
modifications which have not been exemplified can be devised
without departing from the scope of the present disclosure.
For example, at least one of the constituent components may
be modified, added, or eliminated. At least one of the
10 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.
15 DESCRIPTION OF THE REFERENCE CHARACTERS
[0037] 1 fuel injection valve
2 solenoid device
3 core
4 spring
20 5 holder
5a holder inner peripheral surface
6 valve body
61 armature
61a armature sliding portion
25 62 tubular body
20
63 valve portion
63a valve portion sliding portion
7 valve seat
7a valve seat inner peripheral surface
5 8 plate
10 cutout layer
10a through hole
10b cutout
11 penetration layer
10 12a axial web
12b circumferential web
21
We Claim :
[1] A fuel injection valve in which a valve body having
an armature made of a magnetic material, a tubular body
connected to the armature, and a valve portion connected to
5 the tubular body slides in an axial direction inside a holder
by a magnetic attraction force generated by a solenoid
device, wherein
a cross-section of the tubular body has a C shape,
the tubular body includes an elastic portion having
10 an opening formed so as to be shorter in the axial direction
than in a circumferential direction, in an intermediate
portion in the axial direction of the tubular body,
a clearance between the armature and an armature
sliding portion serving as a guide during sliding is set to
15 be larger than a clearance between the valve portion and a
valve portion sliding portion serving as a guide during
sliding, and
a distance from the elastic portion to the armature
sliding portion is longer than a distance from the elastic
20 portion to the valve portion sliding portion.
[2] The fuel injection valve according to claim 1,
wherein
22
the opening of the elastic portion includes at
least one through hole and at least one cutout formed at an
end portion of the tubular body, and
an axial plate portion is provided between the
5 through hole and the cutout.
[3] The fuel injection valve according to claim 2,
wherein
the opening of the elastic portion further includes
10 another through hole arranged so as to be displaced from the
through hole in the axial direction and the circumferential
direction, and
a circumferential plate portion is provided between
the through hole and the other through hole.
15

23
[4] The fuel injection valve according to claim 3,
wherein
the tubular body, the armature, and the valve
portion are welded to each other, and
5 the other through hole is formed on each of the
armature side and the valve portion side of the tubular body.