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Patent Abstract
A solenoid valve comprises a plunger provided in a case so as to
be magnetically moved, a coil provided in the case for generating
a magnetic force, a yoke provided in the case for transmitting the
magnetic force to the plunger, a sleeve, and a valve provided in
the sleeve so as to be slidable within the sleeve in accordance
with a movement of the plunger in order to switch a flow path, wherein
the yoke and the sleeve are formed so as to be fitted together,
and after the sleeve is fitted to the yoke, the sleeve is fixed
from outside of a portion at which the sleeve and either one of
the case or the yoke are overlapped each other.
Patent Claims
1. A solenoid valve comprising: a plunger provided in a case so
as to be magnetically moved; a coil provided in the case for generating
a magnetic force; a yoke provided in the case for transmitting the
magnetic force to the plunger; a sleeve and a valve provided in
the sleeve so as to be slidable within the sleeve in accordance
with a movement of the plunger in order to switch a flow path, wherein
the yoke and the sleeve are formed so as to be fitted together,
and after the sleeve is fitted to the yoke, the sleeve is fixed
from outside of a portion at which the sleeve and either one of
the case or the yoke are overlapped each other.
2. A solenoid valve according to claim 1, wherein a shape of an
inner peripheral surface of the case is identical with a shape of
an outer peripheral surface of the sleeve, and after the sleeve
is fitted to the case, and the sleeve is mounted to the yoke, the
case and the sleeve are fixed together from outside of a portion
at which the sleeve and the case are overlapped each other.
3. A solenoid valve according to claim 2, wherein the case and
the sleeve are fixed together by means of a laser welding.
4. A solenoid valve according to claim 2, wherein the case and
the sleeve are fixed together by means of caulking.
5. A solenoid valve according to claim 4, wherein a groove that
is used for the caulking is formed on the sleeve.
6. A solenoid valve according to claim 2, wherein a diaphragm is
provided between the sleeve and the yoke in a manner where its inner
peripheral portion is fixed to the valve, and its outer peripheral
portion is sandwiched between the yoke and the sleeve, and a stepped
portion is formed on the diaphragm through which the sleeve is concentricity
fit to the yoke.
7. A solenoid valve according to claim 1, wherein the yoke includes
a cylindrical portion, a part of the sleeve is overlapped on an
inner surface of the cylindrical portion of the yoke, the sleeve
includes a groove on which the yoke is overlapped, the yoke is fused
at a portion where the yoke and the sleeve are overlapped each other,
and the fused yoke is reserved in the groove of the sleeve.
8. A manufacturing method for a solenoid valve according to claim
1 comprising processes of: forming the yoke by use of an iron-based
material; forming a cylindrical portion on the yoke; inserting a
part of the sleeve into the cylindrical portion of the yoke so as
to be overlapped each other; forming a groove on the sleeve at a
portion on which the sleeve is overlapped, and fusing the yoke at
the portion on which the sleeve is overlapped in circumstances where
the groove is positioned under the portion of the yoke.
9. A manufacturing method for a solenoid valve according to claim
8, wherein the yoke is fused by means of a laser radiation at the
portion on which the sleeve is overlapped.
10. A manufacturing method for a solenoid valve according to claim
8, wherein, when the yoke is fused by means of the laser radiation,
a filler wire is positioned at the portion where the yoke is fused.
11. A binding method between an iron-based member and an aluminum-based
member, the iron-based member being made of an iron-based material
so as to include a cylindrical portion, and the aluminum-based member
being made of an aluminum-based material so as to include a cylindrical
portion or a column portion, which is overlapped on an inner peripheral
surface of the cylindrical portion of the iron-based member, comprising
processes of: forming a groove on the cylindrical portion or the
column portion of the aluminum-based member; inserting the cylindrical
portion or the column portion of the aluminum-based member into
the cylindrical portion of the iron-based member so as to be overlapped
each other, and fusing the iron-based member at a portion on which
the iron-based member and the aluminum-based member are overlapped
each other in circumstances where the groove is positioned under
the iron-based member on which the aluminum-based member is overlapped.
12. A binding method between an iron-based member and an aluminum-based
member according to claim 11, wherein the iron-based member is fused
by means of a laser radiation at the portion on which the aluminum-based
member is overlapped.
13. A binding method between an iron-based member and an aluminum-based
member according to claim 11, when the iron-based member is fused
by means of the laser radiation, a filler wire is positioned at
the portion where the iron-based member is fused.
14. A binding method between a sleeve and a solenoid mechanism
of a solenoid valve, the sleeve housing a valve mechanism and the
solenoid mechanism driving the valve mechanism, comprising processes
of: forming a cylindrical portion on a solenoid component, which
is made of an iron-based material, the solenoid component being
a part of the solenoid mechanism; inserting a part of the sleeve
into the cylindrical portion of the solenoid component so as to
be overlapped thereon; forming a groove on the sleeve at a portion
on which the solenoid component is overlapped, and fusing the solenoid
component at the portion on which the sleeve is overlapped in circumstances
where the groove is positioned under the solenoid component on which
the sleeve is overlapped.
15. A binding method between a sleeve and a solenoid mechanism
of a solenoid valve according to claim 14, wherein the solenoid
component is fused at the portion on which the sleeve is overlapped
by means of a laser radiation.
16. A binding method between a sleeve and a solenoid mechanism
of a solenoid valve according to claim 14, wherein when the solenoid
component is fused by means of the laser radiation, a filler wire
is positioned at the portion where the solenoid component is fused.
Patent Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and claims priority under 35
U.S.C. .sctn. 119 to Japanese Patent Application 2004-180035 filed
on Jun. 17, 2004, and 2004-332061 filed on Nov. 16, 2004, the entire
content of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention generally relates to a solenoid valve
for switching a fluid flow path of a hydraulic circuit such as an
oil pressure circuit or a solenoid valve for providing a variable
orifice by changing a cross sectional area of the flow path.
BACKGROUND
[0003] A solenoid valve generally includes a cylindrical yoke,
a coil wound around the yoke, a plunger provided inside the yoke
so as to be movable in an axial direction of the yoke, and a valve
moving within a sleeve together with the movement of the plunger
in order to switch a flow path.
[0004] When power is supplied to the coil, a magnetic path is generated
through the yoke and the plunger by which the plunger is attracted,
as a result, the valve is actuated.
[0005] Known solenoid valves are disclosed in JP2000-39083A (especially
in paragraphs 0004, 0005 and FIG. 1), JP2003-329164A (especially
in paragraphs 0033, 0034, and FIGS. 1 through 4) and JP11-002354A.
According to such solenoid valves, an expanded portion is formed
on the sleeve at the yoke side. The expanded portion is expanding
in an outward-radial direction so as to be identical with the shape
of the yoke. In other words, the diameter of the sleeve is elongated
at the end portion of the sleeve. After the sleeve and the yoke
are housed in a case, the sleeve is caulked by the end portion of
the case in order to fix the sleeve to the yoke in a manner where
the end portion of the case is bent inward.
[0006] A conventional art will be explained more specifically in
accordance with FIG. 7.
[0007] As shown in FIG. 7, a sleeve 40 houses a valve spool 41
so as to be movable in vertical direction in FIG. 7. A left end
portion of the sleeve 40 is expanded in a radial direction so as
to form an expanded portion 40a, whose diameter is larger than a
diameter of a central portion of the sleeve 40.
[0008] A yoke 43, a coil 44 and a plunger 45 are provided inside
a case 42. When power is supplied to the coil 44, a magnetic path
is formed among the coil 44, the yoke 43 and the plunger 45, and
then the plunger 45 is moved in the right direction.
[0009] Because the plunger 45 is engaged with the valve spool 41,
the valve spool 41 is also moved in conjunction with the movement
of the plunger 45. Thus, the valve can be switched to be opened
or closed. The case 42 includes a stepped portion 42a at which the
case 42 can be engaged with the yoke 43.
[0010] The yoke 43 and the sleeve 40 are mounted to the case 42
as follow. First, a right end surface of the yoke 43 contacts to
a left end surface of the expanded portion 40a of the sleeve 40.
Then, a right end 42b formed on the case 42 is bent so as to fix
the case 42 to the sleeve 40 and the yoke 43.
[0011] Generally, the solenoid valve is comprised of a valve mechanism
such as a spool valve, and a solenoid mechanism for driving the
valve mechanism, and such solenoid valve is housed in or connected
to a variety of components. If such components are made of a metal
other than an iron, such as an aluminum, a material of the component,
which surrounds the solenoid valve, needs to be made of a metal
except an iron, such as an aluminum in order to prevent a clearance
generated by a thermal expansion difference between the solenoid
valve and the component.
[0012] However, a portion in which the solenoid mechanism is housed
cannot be made of an aluminum because a magnetic circuit is comprised
of the portion in which the solenoid mechanism is housed. Thus,
the sleeve in which the valve mechanism is housed is made of an
aluminum-based material so as to be connected to a part of the solenoid
mechanism such as a solenoid case.
[0013] In JP2000-39083A, JP2003-329164A and JP11-002354A, the sleeves
are connected to the solenoid case by means of caulking. Further
according to a solenoid valve disclosed in JP2002-122261A (especially
in paragraphs 0024 through 0031 and FIG. 2), a sleeve is connected
to a solenoid case by welding in order to stop using O-ring, which
is used for caulking.
[0014] The conventional art disclosed in JP2002-122261A employs
a weld joint structure in which a flange portion of a sleeve is
fixed to a solenoid case in a manner where the inner peripheral
surface of the solenoid case overlaps on the outer peripheral surface
of the flange portion of the sleeve.
[0015] The solenoid case is welded to the flange portion of the
sleeve by means of a heat from a welding heat source (e.g. YAG laser)
applied from a welding equipment such as a YAG laser welding device
to the solenoid case, which is comprised of an iron-based material.
Thus, the solenoid case that is comprised of an iron-based material
is fused at first by means of the heat of the welding heat source,
and then the heat is conducted to the sleeve, which is made of an
aluminum-based material, as a result the aluminum-based material
of the sleeve is fused. Then, the fused metal of the iron-based
material and the fused metal of the aluminum-based material, are
mixed together, and then such mixed metals are cooled so as to be
hardened. In this way, the welding is applied to an entire circumference
of the solenoid case in order to weld the solenoid case to the sleeve.
[0016] When the case is deformed so as to be caulked to the sleeve,
an expanded portion, which is expanded outward, needs to be formed
on the end portion of the sleeve to which the case is caulked in
order to fix the sleeve to the case. In other words, a stepped portion
needs to be formed on the sleeve in order to fix the sleeve to the
case. As a result, costs for manufacturing the sleeve has been increased.
Further, the sleeve needs to be designed in order to prevent a shaft
thereof from being out of alignment. Furthermore, a stepped portion
needs to be formed on the solenoid case, and inside of the stepped
portion of the solenoid case, the sleeve and the yoke are provided
so as to be coaxial with the solenoid case. Such solenoid case need
to be manufactured precisely that may result in high cost.
[0017] In addition, when the iron and the aluminum are fused at
greater than 400.degree. C., a fragile compound or a ductile compound,
such as aFeAI.sub.2 or Fe.sub.2AI.sub.5, are made as indicated in
a binary state diagram in FIG. 6 (.quadrature.BINARY ALLOY PHASE
DIAGRAMS(AECOND EDITION).quadrature.Vol.1, P.148, Published by ASM
International).
[0018] When the aluminum of the sleeve and the iron-based fused
metal of the solenoid case are fused and mixed together in order
to connect the sleeve to the solenoid case, because the strength
of the fused metal is small, a lot of fusion processes needs to
be applied to many places, as a result, times and energy are required
to fix the sleeve to the solenoid case.
[0019] Thus, a need exist for producing a solenoid valve in which
a expanded portion, which is formed on a sleeve so as to protrude
outwardly, is not formed in order to produce the solenoid valve
at a moderate price. Specifically, a need exist for producing a
solenoid valve in which an aluminum-based member of a sleeve can
be fixed to an iron-based fused metal of the solenoid case at a
moderate price.
SUMMARY OF THE INVENTION
[0020] A solenoid valve comprises a plunger provided in a case
so as to be magnetically moved, a coil provided in the case for
generating a magnetic force, a yoke provided in the case for transmitting
the magnetic force to the plunger, a sleeve, and a valve provided
in the sleeve so as to be slidable within the sleeve in accordance
with a movement of the plunger in order to switch a flow path, wherein
the yoke and the sleeve are formed so as to be fitted together,
and after the sleeve is fitted to the yoke, the sleeve is fixed
from outside of a portion at which the sleeve and either one of
the case or the yoke are overlapped each other.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The foregoing and additional features and characteristics
of the present invention will become more apparent from the following
detailed description considered with reference to the accompanying
drawings, wherein:
[0022] FIG. 1 illustrates a cross section of a solenoid valve in
the first embodiment according to the present invention;
[0023] FIG. 2 illustrates a cross section of a solenoid valve in
the second embodiment during a manufacturing process;
[0024] FIG. 3 illustrates a front view of the solenoid valve in
FIG. 2 that has been assembled,
[0025] FIG. 4 illustrates a cross section of a solenoid valve of
another embodiment;
[0026] FIG. 5 illustrates an enlarged diagram of a part of the
solenoid valve in FIG. 4;
[0027] FIG. 6 illustrates a binary state diagram indicating a relationship
between an iron and an aluminum, and
[0028] FIG. 7 illustrates a cross section of a solenoid valve according
to a related art.
DETAILED DESCRIPTION
[0029] Embodiments to implement the present invention will be explained
in accordance with drawings attached hereto.
First Embodiment
[0030] FIG. 1 illustrates a cross section of a solenoid valve 20
according to the first embodiment. As shown in FIG. 1, the solenoid
valve 15 includes a hollowed cylindrical sleeve 1 having ports 1a.quadrature.1b
and 1c, and a case 5 formed in a cup-shape and positioned at one
side the sleeve 1 (right end in FIG. 1). Further, a valve spool
2 is provided in the sleeve 1 so as to be movable within the sleeve
1 in an axial direction of the sleeve 1. A valve stopper 13 is fitted
to the other side (left end in FIG. 1) of the sleeve 1 in order
to regulate the movement of the valve spool 2 in a left direction.
Further, a spring 3 being compressed is provided between the valve
spool 2 and the valve stopper 13 in order to bias the valve spool
2 in a right direction in FIG. 1.
[0031] A cylindrical bobbin 11 to which a coil 9 is wound is provided
in the case 5. In the bobbin 11, a first yoke 6 and a second yoke
7, which are made of a magnetic material, are provided coaxially.
More specifically, the first yoke 6 is positioned inside and on
the left side of the bobbin 11 in FIG. 1. On the other hand, the
second yoke 7 is positioned inside and the right side of the bobbin
11.
[0032] Inside the both yokes 6 and 7, a cylindrical plunger 4,
which is made of a magnetic material, is provided so as to be movable
in a longitudinal direction in FIG. 1. A left end of the plunger
4 in FIG. 1 engages with an end portion of the valve spool 2, which
is biased by means of the spring 3, and a right end of the plunger
4 in FIG. 1 engages with a stopper 14, which is formed on a bottom
portion of the cup-shaped case 5 integrally therewith, in order
to regulate the rightward movement of the plunger 4.
[0033] On the outside of the case 5, a connector 10 having a terminal
12, which is electrically connected to an end portion of the coil
9, is provided. When power is supplied to the terminal 12, the coil
9 is conducted, as a result, a magnetic field is generated through
the coil 9, the first yoke 6 and the second yoke 7, which are functioning
together.
[0034] Further, a diaphragm 8 is provided between the sleeve 1
and the yoke 6. Specifically, an inner peripheral portion of the
diaphragm 8 is fit to a groove, which is formed near the right end
portion of the valve spool 2, and an outer peripheral portion of
the diaphragm 8 is sandwiched between the right end of the sleeve
1 and the left end of the yoke 6. By use of the diaphragm 8, a space
inside the solenoid valve 15 is divided into a space A, which is
formed by the diaphragm 8, the sleeve 1 and the valve spool 2, and
a space B, which is formed by the diaphragm 8, the first yoke 6
and the plunger 4.
[0035] A protruding portion 1d, whose outer diameter is identical
with an outer diameter of the sleeve 1, is formed on the right end
of the sleeve 1. Further, a protruding portion 6a, whose inner diameter
is identical with an inner diameter of the first yoke 6, is formed
on the left end of the yoke 6. The inner diameter of the protruding
portion 1d of the sleeve 1 is approximately identical with the outer
diameter of the protruding portion 6a of the first yoke 6.
[0036] A protruding length of the protruding portion 1d of the
sleeve 1 is longer than a protruding length of the protruding portion
6a of the first yoke 6. In circumstances where the protruding portion
1d of the sleeve 1 is engaged with an outer surface 6d (left surface
in FIG. 1) of the first yoke 6, an outer peripheral portion of the
diaphragm 8 is positioned in a space, which is formed between a
left end surface of the protruding portion 6a of the first yoke
6 and an inner surface 1e of the sleeve 1, and sandwiched therebetween.
[0037] After the second yoke 7, the bobbin 11 with the coil 9,
the plunger 4 and the first yoke 6 are assembled to the case 5,
the sleeve 1 to which the valve spool 2 is mounted is fixed to the
case 5 by means of a laser welding or a caulking at point where
the case 5 overlaps on the sleeve 1 from outside of the case 5.
Thus, the sleeve 1 is fixed to the case 5.
[0038] At this point, the first yoke 6, the bobbin 11 and the second
yoke 7 are fixed within the case 5 in circumstances where the sleeve
1 is positioned coaxially with the first yoke 6.
[0039] The port 1a and the port 1b are communicating when the valve
spool 2 is in a state shown in FIG. 1 When the coil 9 is conducted
so that the valve spool 2 is moved leftward in FIG. 1, the communication
between the port 1a and the port 1b is closed.
[0040] An actuation of the solenoid valve 15 having the above configuration
will be explained.
[0041] When the power is not supplied to the coil 9, the valve
spool 2 and the plunger 4 are biased rightward in FIG. 1 by means
of the spring 3, and the plunger 4 is engaged with the stopper 14
so that the movement of the plunger 4 is limited.
[0042] In this state, the port 1a and the port 1b are communicating
by means of the valve spool 2. On the other hand, when the terminal
12 is energized so as to supply the power to the coil 9, a magnetic
field is generated around the coil 9. Because the magnetic field
passes through the first yoke 6, the plunger 4 and the second yoke
7 sequentially (or in a reverse direction), a force is applied to
the plunger 4 in the left direction in FIG. 1.
[0043] Thus, the valve spool 2 and the plunger 4 are integrally
moved leftward against the biasing force of the spring 3 by means
of the magnetic force, as a result, the communication between the
port 1a and the port 1b is closed.
[0044] By adjusting the level of the power supplied to the coil
9 by means of a duty control, the valve spool 2 is controlled so
as to stop at an intermediate position, or by controlling the valve
spool 2 so as to be opened/closed rapidly, diameters of the orifices
of the port 1a and the port 1b are adjusted. Such solenoid valve
is called a linear solenoid valve.
[0045] Even when foreign objects is mixed into fluid that flows
into the ports 1a.quadrature.1b and 1c, such foreign objects can
be stopped in front of the plunger 4 by means of the diaphragm 8.
[0046] In the above configuration, the case 5 can be made of a
steel plate by means of a press molding. Because the stopper 14
is formed integrally with the case 5, the number of the parts used
for manufacturing the solenoid valve 15 can be reduced. Further,
because the stopper 14 is coaxial with the case 5, the end portion
of the case 5 doesn't need to be manufactured all that precisely.
Further, because the thickness of the case 5 except a portion, at
which the stopper 14 is formed, is formed so as to be even, the
case 5 can be made of a plate, which has a uniform thickness, as
a result, the cost of the case 5 can be reduced.
[0047] Further, the diameter of the outer peripheral surface of
the sleeve 1, including the protruding portion 1d, are basically
even, so that the sleeve 1 can be formed simply by processing the
ports 1a.quadrature.1b and 1c to a cylindrical member. Thus, the
cost for processing the sleeve 1 can be reduced.
[0048] When the sleeve 1 is fixed to the case 5 by means of a caulking,
it is preferable that a groove for caulking is formed on the sleeve
1 in advance. Thus, the case 5 can be fixed to the sleeve 1 in a
manner where the case 5 is deformed so as to fit into the groove
formed on the sleeve 1 by pressing the case 5 from outside thereof.
[0049] When a laser welding or a caulking is used in order to fix
the case 5 to the sleeve 1, a load is applied radially. Thus, because
a level of a load, which is applied to the solenoid valve 15 in
an axial direction, is small, the level of a caulking load that
is applied to the bobbin 11 and the yokes 6 and 7 can be reduced.
[0050] A configuration of the first embodiment according to the
present invention is not limited to the above configuration. The
configuration of the first embodiment may be modified as follow.
[0051] In the first embodiment, the valve is comprised of the sleeve
1 and the valve spool 2, which slides within the sleeve 1. However,
another type of a valve may be used alternatively. In addition,
the shape of the valve may be changed so as to have three ports
or more.
[0052] Further, the cylindrical protruding portion of the sleeve
1 is fit to the cylindrical protruding portion of the first yoke
6 in the first embodiment. The shapes of the protruding portions
are not limited to the cylindrical shape. The protruding portions
may be formed in another shape. However, because the shape of the
sleeve 1 and the first yoke 6 is cylindrical, it is preferable that
the shape of each of the protruding portions is the same as the
shape of the sleeve 1 and the first yoke 6. In this configuration,
the process for manufacturing the sleeve 1 and the first yoke 6
can be simplified, and the cost of manufacturing the sleeve 1 and
the first yoke 6 can be reduced.
[0053] Further, in the first embodiment, the sleeve 1 is fixed
to the case 5 by means of a laser welding or a caulking. When the
sleeve 1 is fixed to the case 5 by means of a laser welding, there
is no need to use a screw. Further, when the sleeve 1 is fixed to
the case 5 by means of a caulking, there is also no need to use
a screw; in addition, an assembling process can be simplified. Another
fixing method can be used alternatively. For example, the sleeve
1 may be fixed to the case 5 by means of a screw.
Second Embodiment
[0054] FIG. 2 and FIG. 3 illustrate cross sections of the solenoid
valve 20 according to the second embodiment. Specifically, FIG.
2 illustrates the solenoid valve 20 in which a sleeve 21 is not
fixed to the solenoid member, and FIG. 3 illustrates the solenoid
valve 20 in which the sleeve 21 has been fixed to the solenoid member.
The solenoid valve 20 includes a valve mechanism, which is comprised
of a sleeve 21 and a spool valve 22, and a solenoid mechanism, which
is comprised of a case 23, a housing 24, a first yoke 25, a second
yoke 26, a coil 27, a plug 28, a plunger 29, and a bobbin 31.
[0055] The sleeve 21 is formed in a cylindrical shape, and ports
21a, 21b and 21c are formed on the sleeve 21. The sleeve 21 is mounted
to a valve block (not shown) after the solenoid valve has been assembled.
In order to enhance an ability to fix to the valve block, the sleeve
21 is made of approximately the same material as a material of the
valve block.
[0056] Normally, the sleeve 21 is made of an aluminum-based material
(a metal whose main material is an aluminum). The spool valve 22
is formed in a long shape and provided so as to be slidable on an
inner surface of the sleeve 21.
[0057] A groove 22a is formed on the spool valve 22, and the groove
22a and ports 21a, 21b and 21c of the sleeve 21 are selectively
switched in accordance with the movement of the spool valve 22 in
order to switch a flow path that is connected to the port.
[0058] In the solenoid mechanism, the bobbin 31 that is made of
resin so as to be in a cylindrical shape is wound by the coil 27,
and a housing 24 is molded by resin on an outer peripheral surface
of the bobbin 31 so as to be integral therewith.
[0059] An end portion of the coil 27 is electrically connected
to a terminal of a connector. Further, a cylindrical plug 28 is
provided inside the bobbin 31, and the first yoke 25 is connected
to the cylindrical plug 28 from one side thereof, and the second
yoke 26 is connected to the cylindrical plug 28 from the other side
thereof.
[0060] Both first yoke 25 and the second yoke 26 are formed in
a cylindrical shape, and a flange portion 25a, protruding in an
radially outward direction, is formed on an end portion of the first
yoke 25, and a flange portion 26a, protruding in a radially outward
direction, is formed on an end portion of the second yoke 26. The
first yoke 25, the second yoke 26 and the bobbin 31 with the coil
27 are inserted into the cylindrical case 23 in circumstances where
an outer peripheral surface of the flange portion 25a of the first
yoke 25 is engaged with the cylindrical case 23, and an outer peripheral
surface of the flange portion 26a of the second yoke 26 is engaged
with the cylindrical case 23.
[0061] The plunger 29 is formed in a cylindrical shape so as to
be slidable within a cylindrical space formed inside the first yoke
25, the plug 28 and the second yoke 26. The plug 28 is made of resin,
and the first yoke 25, the second yoke, the case 23 and the plunger
29 are made of a iron-based fused metal which includes high-permeability
(a material which mainly includes an iron that can be fused by heat).
[0062] An end portion 22b of the spool valve 22 is extending so
as to reach inside the solenoid mechanism in a manner where the
end portion 22b penetrates inside the first yoke 25. Thus, the spool
valve 22 engages with the plunger 29 at the end portion 22b of the
spool valve 22. A biasing force is applied to the spool valve 22
by means of a spring in a direction so that the end portion 22b
of the spool valve 22 engages with the plunger 29. When the power
is not supplied to the coil 27, the plunger 29 is biased by means
of the spring so that the position of the plunger 29 is limited
by means of the stopper 32, which is fixed to the second yoke 26.
[0063] The first yoke 25 includes a cylindrical portion 25b, and
as shown in FIG. 2, an end portion of the sleeve 21 is fit in the
cylindrical portion 25b so as to be overlapped each other. On the
end portion of the sleeve 21, which overlaps on the cylindrical
portion 25b, a groove 21d is formed so as to be in a V-shape.
[0064] Further, the diaphragm 30 is provided between the sleeve
21 and the first yoke 25, and the sleeve 21 is fit to the first
yoke 25 by means of an elastic diaphragm 30. Specifically, an outer
peripheral portion of the diaphragm 30 is sandwiched between the
sleeve 21 and the first yoke 25, and an inner peripheral portion
of the diaphragm 30 is fit in a groove, which is formed on the end
portion 22b of the spool valve 22.
[0065] After the solenoid valve is assembled as shown in FIG. 2,
a laser L (e.g. YAG laser) is applied to a portion at which the
first yoke 25 overlaps on the groove 21d of the sleeve 21, from
outside of the cylindrical portion 25b.
[0066] Because the first yoke 25 is made of an iron-based material,
when the laser radiation is applied to the first yoke 25, the first
yoke 25 is fused at a portion where the laser radiation is applied,
and then the fused iron-based material is stored into the groove
21d. When the application of the laser radiation is stopped, the
fused iron-based material is cooled and hardened in the groove 21d.
Thus, the sleeve 21 is fixed to the first yoke 25.
[0067] As mentioned above, when the power is not supplied to the
terminal of the connector, the plunger 29 is biased by means of
the spring so that the position of the plunger 29 is limited by
means of the stopper 32, which is fixed to the second yoke 26.
[0068] Once the power is supplied to the terminal of the connector,
the power is applied to the coil 27 in order to generate a magnetic
field in a manner where a line of magnetic force of the magnetic
field goes round through the yoke 26, the plunger 29, the first
yoke 25 and the case 23 (or through the case 23, the first yoke
25, the plunger 29 and the yoke 26). At this point, an attraction
force is generated between the first yoke 25 and the plunger 29,
and the plunger 29 is drawn by the first yoke 25. Along with the
movement of the plunger 29, the spool valve 22 is also moved; as
a result, the flow path connected to the port is switched in order
to function as a solenoid valve.
[0069] It is preferable that YAG laser or CO.sub.2 laser is applied
to the overlapped portion. Instead of the laser radiation, plasma
may be applied to the overlapped portion in order to fuse the iron-based
material. Further, the iron-based material may be heated by means
of another method in order to fuse the overlapped portion. However,
because the connector portion of the solenoid valve is protruding
as shown in FIGS. 2 and 3, it is preferable that the laser radiation
is applied to a point so as to be heated and fused.
[0070] When the laser is applied from the above of the solenoid
valve 20, it is preferable that a central axis of the solenoid valve
20 is positioned horizontally. Even when the solenoid valve 20 is
positioned so as to be tilted .+-.45 degrees relative to a horizontal
line, the fused metal can be stored in the groove 21d. Thus, when
the position of the solenoid valve 20 is limited in the manufacturing
process, the solenoid valve 20 may be positioned so as to be tilted.
[0071] In the second embodiment shown in FIG. 2, the diaphragm
30 is provided in order to seal between the sleeve 21 and the first
yoke 25. Thus, the groove 21d needs to be formed on at least one
portion of the outer peripheral surface of the sleeve 21. More preferably,
the groove 21d formed on the end portion of the sleeve 21 may be
provided on entire circumference of the outer peripheral surface
of the sleeve 21, and the laser is applied from above of the solenoid
valve 20 toward the groove 21d by rotating the solenoid valve 20
through 360-degree about its axis. Thus, fused material is stored
into the groove 21d over entire circumference; as a result, the
sleeve 21 can be firmly fixed to the first yoke 25.
[0072] When the laser is applied to the first yoke 25, the metal
of the first yoke 25 may evaporate, and the metal around the evaporate
portion may be fused, and then the fused metal is stored into the
groove 21d. In this case, the amount of the fused metal, which is
stored in the groove 21d, may short. Thus, if the amount of the
fused metal stored in the groove 21d shorts, a filler wire 33 may
be used in order to compensate the amount of the fused metal. Specifically,
the filler wire 33 is placed near the first yoke 25 to which the
laser is applied, and the filler wire 33 is fused at the same time
as the first yoke 25 is fused by applying the laser in order to
compensate the amount of the fused metal. Then, as shown in FIG.
5, the fused filler wire 33 is stored into a keyhole, which is formed
due to the evaporation of the metal of the first yoke 25 by the
laser radiation, in order to increase the amount of the fused metal
stored in the groove 21d. Furthermore, in order to increase the
amount of the fused metal, the solenoid valve 20 may be moved in
an axial direction thereof while the laser is applied to the first
yoke 25. Further, when the groove 21d is formed through entire circumference
of the outer peripheral surface on the end portion of the sleeve
21, the solenoid valve 20 may be reciprocated in an axial direction
thereof and rotated through 360-degree about its axis while the
laser is applied to the first yoke 25.
[0073] In the second embodiment, the first yoke 25 of the solenoid
member is fixed to the sleeve 21. In this method, the outer peripheral
surface of the sleeve 21 is fit in a portion of the cylindrical
portion 25b of the first yoke 25, the portion not being fused by
the laser.
[0074] However, the sleeve 21 may be fixed to another component
of the solenoid mechanism. For example, the sleeve 21 may be fit
to the end portion of the case 23, the end portion being extended,
and a laser is applied to the case 23 from the outside thereof.
When a diameter of the sleeve 21 is near the diameter of the sleeve
21, and a design can be changed by simply changing the outer diameter
of the case 23 so as to be identical with the inner diameter of
the case 23, as a result, and such design change may result in low
costs. In the solenoid valve in which the first yoke 25 is fixed
to the sleeve 21 according to the second embodiment shown in FIGS.
2 through 4, the case 23 is formed in a cylindrical shape, and that
may result in low costs.
[0075] In the second embodiment, a spool valve is used as a valve
mechanism, however, another type of valve may be used as a valve
mechanism. Further, the structure of the solenoid mechanism may
not be limited to the second embodiment.
[0076] This invention may be applied to a binding method between
an iron-based member, which is made of an iron-based material so
as to include a cylindrical portion, and an aluminum-based member,
which is made of an aluminum-based member so as to include a cylinder
portion or a column portion and is inserted into the cylindrical
portion of the iron-based member.
[0077] In the second embodiment, the iron based member is the first
yoke 25 including the cylindrical portion 25b, however, the shape
of the first yoke 25 may not be cylindrical, and may be a tube-shape.
Further, the aluminum-based member is the sleeve 21, and the sleeve
21 is formed in a cylindrical shape, however, unless the sleeve
21 is inserted in the iron-base member, the sleeve 21 may be formed
in a tube-shape or a column shape. The tube portion or the column
portion of the aluminum-based member is inserted in the cylindrical
portion of the iron-based member so as to overlapped each other,
and in circumstances where the groove is positioned under the overlapped
portion of the iron-based member, the overlapped portion of the
iron-based member is fused.
[0078] In this alternative configuration, the overlapped portion
of the iron-based member may be fused by means of a laser radiation
in the same manner as the second embodiment. Further, a filler wire
may be used at the overlapped portion to compensate the fused metal
in the same manner as the second embodiment.
[0079] According to claim 1, a solenoid valve comprises a plunger
provided in a case so as to be magnetically moved, a coil provided
in the case for generating a magnetic force, a yoke provided in
the case for transmitting the magnetic force to the plunger, a sleeve,
and a valve provided in the sleeve so as to be slidable within the
sleeve in accordance with a movement of the plunger in order to
switch a flow path, wherein the yoke and the sleeve are formed so
as to be fitted together, and after the sleeve is fitted to the
yoke, the sleeve is fixed from outside of a portion at which the
sleeve and either one of the case or the yoke are overlapped each
other.
[0080] Thus, when a magnetic field is generated by the coil, a
magnetic path is formed between the yoke and the plunge, as a result,
the plunger is moved. Together with the movement of the plunger,
the valve is moved within the sleeve so as to switch a flow path.
In this solenoid valve, there is no need to form an expanded portion
on the sleeve, the expanded portion being protruding outward. Thus,
the sleeve can be manufactured by means of a simple cutting process.
Further, because the yoke and the sleeve are formed so as to be
able to fit together, the sleeve can be fit to the yoke coaxially
therewith.
[0081] According to claim 2, a shape of an inner peripheral surface
of the case is identical with a shape of an outer peripheral surface
of the sleeve, and after the sleeve is fitted to the case, and the
sleeve is mounted to the yoke, the case and the sleeve are fixed
together from outside of a portion at which the sleeve and the case
are overlapped each other.
[0082] Thus, when a magnetic field is generated by the coil, a
magnetic path is formed between the yoke and the plunge, as a result,
the plunger is moved. Together with the movement of the plunger,
the valve is moved within the sleeve so as to switch a flow path.
In this solenoid valve, there is no need to form an expanded portion
on the sleeve, the expanded portion being protruding outward. Thus,
the sleeve can be manufactured by means of a simple cutting process.
Further, because the yoke and the sleeve are formed so as to be
able to fit together, the sleeve can be fit to the yoke coaxially
therewith. Furthermore, the case is fixed to the sleeve in circumstances
where the yoke is sandwiched between the case and the sleeve, as
a result the yoke can be fixed between the case and the sleeve.
In this configuration, the case is formed in a simple cup-shape,
so that the cost for manufacturing the solenoid valve can be reduced.
[0083] According to claim 3, the case and the sleeve are fixed
together by means of a laser welding.
[0084] Thus, the sleeve can be easy fixed to the case from the
outside of the case.
[0085] According to claim 4, the case and the sleeve are fixed
together by means of caulking.
[0086] Thus, the sleeve can be easy fixed to the case from the
outside of the case.
[0087] According to claim 5, a groove that is used for the caulking
is formed on the sleeve.
[0088] Thus, the sleeve can be precisely fixed to the case, and
the solenoid valve can have a waterproof structure. Such solenoid
valve can be made at a moderate cost.
[0089] According to claim 6, a diaphragm is provided between the
sleeve and the yoke in a manner where its inner peripheral portion
is fixed to the valve, and its outer peripheral portion is sandwiched
between the yoke and the sleeve, and a stepped portion is formed
on the diaphragm through which the sleeve is concentricity fit to
the yoke.
[0090] Thus, a solenoid side, in which a magnetic field is generated
when power is supplied to the coil, can be sealed and separated
from a valve side, in which a flow path is switched. Further, an
outer peripheral portion of the diaphragm can be fixed at the same
time when the sleeve is fit to the yoke, as a result, manufacturing
efficiency can be improved. Such solenoid valve can be made at a
moderate cost.
[0091] According to claim 7, the yoke includes a cylindrical portion,
a part of the sleeve is overlapped on an inner surface of the cylindrical
portion of the yoke, the sleeve includes a groove on which the yoke
is overlapped, the yoke is fused at a portion where the yoke and
the sleeve are overlapped each other, and the fused yoke is reserved
in the groove of the sleeve.
[0092] Thus, the fused metal of the overlapped portion of the yoke
is reserved in the groove of the sleeve and then the fused metal
is hardened in the groove. Thus, the sleeve is fixed to the yoke
by means of the metal in the groove.
[0093] According to claim 8, a manufacturing method for a solenoid
valve according to claim 1 comprises processes of forming the yoke
by use of an iron-based material, forming a cylindrical portion
on the yoke, inserting a part of the sleeve into the cylindrical
portion of the yoke so as to be overlapped each other, forming a
groove on the sleeve at a portion on which the sleeve is overlapped,
and fusing the yoke at the portion on which the sleeve is overlapped
in circumstances where the groove is positioned under the portion
of the yoke.
[0094] Thus, the fused metal of the overlapped portion of the yoke
is reserved in the groove of the sleeve and then the fused metal
is hardened in the groove. Thus, the sleeve is fixed to the yoke
by means of the metal in the groove.
[0095] According to claim 9, the yoke is fused by means of a laser
radiation at the portion on which the sleeve is overlapped.
[0096] Thus, only the over lapped portion of the yoke can be fused
in a short period of time.
[0097] According to claim 10, the yoke is fused by means of the
laser radiation, a filler wire is positioned at the portion where
the yoke is fused.
[0098] Thus, because the fused filler wire is mixed to the fused
yoke, the amount of the fused metal stored in the groove of the
sleeve can be increased.
[0099] According to claim 11, a binding method between an iron-based
member and an aluminum-based member, the iron-based member being
made of an iron-based material so as to include a cylindrical portion,
and the aluminum-based member being made of an aluminum-based material
so as to include a cylindrical portion or a column portion, which
is overlapped on an inner peripheral surface of the cylindrical
portion of the iron-based member, comprises processes of forming
a groove on the cylindrical portion or the column portion of the
aluminum-based member, inserting the cylindrical portion or the
column portion of the aluminum-based member into the cylindrical
portion of the iron-based member so as to be overlapped each other,
and fusing the iron-based member at a portion on which the iron-based
member and the aluminum-based member are overlapped each other in
circumstances where the groove is positioned under the iron-based
member on which the aluminum-based member is overlapped.
[0100] Thus, the fused metal of the overlapped portion of the iron-based
member is reserved in the groove of the aluminum-based member, and
then the fused metal is hardened in the groove. Thus, the aluminum-based
member is fixed to the iron-based member by means of the metal in
the groove.
[0101] According to claim 12, the iron-based member is fused by
means of a laser radiation at the portion on which the aluminum-based
member is overlapped.
[0102] Thus, only the over lapped portion of the iron-based member
can be fused in a short period of time.
[0103] According to claim 13, when the iron-based member is fused
by means of the laser radiation, a filler wire is positioned at
the portion where the iron-based member is fused.
[0104] Thus, the fused iron-based member and the fused filler wire
are mixed so as to increase the amount of the fused metal reserved
in the groove of the aluminum-based member.
[0105] According to claim 14, a binding method between a sleeve
and a solenoid mechanism of a solenoid valve, the sleeve housing
a valve mechanism and the solenoid mechanism driving the valve mechanism,
comprises processes of forming a cylindrical portion on a solenoid
component, which is made of an iron-based material, the solenoid
component being a part of the solenoid mechanism, inserting a part
of the sleeve into the cylindrical portion of the solenoid component
so as to be overlapped thereon, forming a groove on the sleeve at
a portion on which the solenoid component is overlapped, and fusing
the solenoid component at the portion on which the sleeve is overlapped
in circumstances where the groove is positioned under the solenoid
component on which the sleeve is overlapped.
[0106] Thus, the fused metal of the overlapped portion of the solenoid
member is reserved in the groove of the sleeve, and then the fused
metal is hardened in the groove. Thus, the sleeve is fixed to the
solenoid member by means of the metal in the groove.
[0107] According to claim 15, the solenoid component is fused at
the portion on which the sleeve is overlapped by means of a laser
radiation.
[0108] Thus, only the over lapped portion of the solenoid member
can be fused in a short period of time.
[0109] According to claim 16, when the solenoid component is fused
by means of the laser radiation, a filler wire is positioned at
the portion where the solenoid component is fused.
[0110] Thus, the fused solenoid member and the fused filler wire
are mixed so as to increase the amount of the fused metal reserved
in the groove of the sleeve.
[0111] The principles, preferred embodiment and mode of operation
of the present invention have been described in the foregoing specification.
However, the invention which is intended to be protected is not
to be construed as limited to the particular embodiments disclosed.
Further, the embodiments described herein are to be regarded as
illustrative rather than restrictive. Variations and changes may
be made by others, and equivalents employed, without departing from
the sprit of the present invention. Accordingly, it is expressly
intended that all such variations, changes and equivalents which
fall within the spirit and scope of the present invention as defined
in the claims, be embraced thereby. |