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Patent Abstract
A solenoid actuator of a solenoid valve has a solenoid, a yoke,
a stator, a cup and a restrained portion. The yoke radially surrounds
the stator while radially forming an outer circumferential gap therebetween.
The cup receives a plunger. The cup is arranged in the stator while
radially forming an inner circumferential gap therebetween. The
restrained portion is axially inserted between an internal portion
of the yoke and the stator. The outer circumferential gap is greater
than the inner circumferential gap. Therefore, even when the inner
circumferential gap is set to be small to effectively apply magnetic
power generated by the solenoid to the plunger, radial misalignment
of the cup can be accommodated by the outer circumferential gap.
Patent Claims
What is claimed is:
1. A solenoid actuator comprising: a solenoid; a plunger that is
arranged substantially coaxially with respect to the solenoid; a
stator that has a substantially annular shape defining an inner
circumferential face; a cylindrical cup that is arranged radially
inside of the inner circumferential face of the stator, the cup
receiving the plunger such that the plunger is substantially axially
slidable in the cup; a cylindrical yoke that radially surrounds
the solenoid and an outer circumference of the stator; and a magnetic
force transferring member that is axially inserted between a step
portion formed in an inner circumference of the yoke and a radially
outer portion of the stator to axially transfer magnetic force between
the yoke and the stator, wherein the outer circumference of the
stator radially forms a first gap with an inner circumferential
face of the yoke therebetween, the inner circumferential face of
the stator radially forms a second gap with an outer circumferential
face of the cup therebetween, and the first gap is greater than
the second gap.
2. The solenoid actuator according to claim 1, further comprising
a bracket that includes: a restrained portion that is restrained
in the yoke to serve as the magnetic force transferring member;
and a fixed portion that externally secures the yoke, wherein the
cup includes a collar portion that radially extends outwardly from
an outer circumference of the cup, and the collar portion is disposed
on an axially opposite side as the solenoid with respect to the
restrained portion.
3. The solenoid actuator according to claim 2, wherein the stator
is separated from the bracket.
4. The solenoid actuator according to claim 1, wherein the stator,
the yoke and the plunger form a magnetic circuit to magnetically
attract the plunger.
5. A solenoid valve comprising: a solenoid actuator including,
a solenoid, a plunger that is arranged substantially coaxially with
respect to the solenoid, a stator that has a substantially annular
shape defining an inner circumferential face, a cylindrical cup
that is arranged radially inside of the inner circumferential face
of the stator, the cup receiving the plunger such that the plunger
is substantially axially slidable in the cup, a cylindrical yoke
that radially surrounds the solenoid and an outer circumference
of the stator, and a magnetic force transferring member that is
axially inserted between a step portion formed in an inner circumference
of the yoke and a radially outer portion of the stator to axially
transfer magnetic force between the yoke and the stator; and a valve
body that connects to the plunger, such that the valve body is axially
actuated by the plunger to open and close a fluid channel, wherein
the outer circumference of the stator radially forms a first gap
with an inner circumferential face of the yoke therebetween, the
inner circumferential face of the stator radially forms a second
gap with an outer circumferential face of the cup therebetween,
and the first gap is greater than the second gap.
6. The solenoid valve according to claim 5, wherein the solenoid
actuator further includes a bracket that includes: a restrained
portion that is restrained in the yoke to serve as the magnetic
force transferring member; and a fixed portion that externally secures
the yoke, the cup includes a collar portion that radially extends
outwardly from an outer circumference of the cup, and the collar
portion is disposed on a side of the valve body axially with respect
to the restrained portion.
7. The solenoid valve according to claim 6, wherein the stator
is separated from the bracket.
8. The solenoid valve according to claim 5, wherein the stator,
the yoke and the plunger form a magnetic circuit to magnetically
attract the plunger.
Patent Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based on and incorporates herein by
reference Japanese Patent Applications No. 2003-294385 filed on
Aug. 18, 2003 and No. 2004-211659 filed on Jul. 20, 2004.
FIELD OF THE INVENTION
[0002] The present invention relates to a solenoid actuator and
a solenoid valve. The solenoid valve includes the solenoid actuator
having a solenoid to generate magnetic force for actuating a valve
body, thereby controlling flow of gas or liquid in fluid channels.
BACKGROUND OF THE INVENTION
[0003] A solenoid valve is incorporated into a hydraulic device
for performing timing control of a variable valve provided in an
internal combustion engine, for example. The solenoid valve is energized
to control the fluid channels in the hydraulic device.
[0004] As shown in FIG. 4, a solenoid valve 100, which is secured
externally to a hydraulic device (not shown), includes a valve body
portion 101 and an actuator portion 103. The valve body portion
101 receives a spool 106 serving as a valve body. The actuator portion
103 receives a plunger 102 to actuate the valve body portion 101.
The valve body portion 101 is incorporated into the hydraulic device
to be communicated with fluid channels (not shown).
[0005] The valve body portion 101 includes a cylindrical sleeve
105, the spool 106, and a spring 107. The sleeve 105 has ports 104
to be coupled to the fluid channels in the hydraulic device. The
spool 106 serves as the valve body for opening or closing the ports
104 by slidably moving along the inner circumferential portion of
the sleeve 105. The spring 107 resiliently urges the spool 106 axially
toward the actuator portion 103. The actuator portion 103 includes
a solenoid 108, the plunger 102, and a cup 109. The solenoid 108
is energized in accordance with a signal transmitted by an ECU (electronic
control unit) to generate magnetic force (attractive force). The
plunger 102 receives the magnetic force generated in the solenoid
108, and actuates the spool 106. The cup 109 slidably sustains the
plunger 102. Here, a magnetic circuit is formed of the plunger 102,
a yoke 110 accommodating the solenoid 108, and a stator 111 provided
between the yoke 110 and the plunger 102 to apply the magnetic force
to the plunger 102. The yoke 110 and the stator 111 also partially
construct the actuator portion 103. The solenoid 108 is energized
in response to a signal transmitted from the ECU, and the plunger
102 is slid inside the cup 109. The spool 106 urged by the spring
107 is slid in the sleeve 105 coaxially with the plunger 102. In
this manner, the ports 104 are opened or closed to control fluid
communication between the fluid channels. An attachment bracket
112 is welded on the outer circumferential face of the yoke 110
to secure the actuator portion 103 on an external portion of the
hydraulic device.
[0006] As shown in FIG. 5, a solenoid valve 100 has a cup 109 fitting
into the inner circumferential face of a stator 111. In this structure,
the cup 109 and the stator 111 are apt to be radially misaligned
with each other. When radial misalignment between the cup 109 and
the stator 111 is not accommodated, magnetic force may be radially
applied between the stator 111 and a plunger 102. Accordingly, the
cup 109 may deform, and the plunger 102 may not slide smoothly.
[0007] Therefore, in this structure, an outer circumferential gap
(radial gap) .alpha. is formed between the inner circumferential
face of the yoke 110 and the outer circumferential face of the stator
111, in order to accommodate radial misalignment of the cup 109.
Besides, an inner circumferential gap (radial gap) .beta. is formed
between the outer circumferential face of the cup 109 and the inner
circumferential face of the stator 111.
[0008] In general, the outer circumferential gap .alpha. is set
to be small as much as possible to axially transfer magnetic force
between the yoke 110 and the stator 111. Accordingly, the inner
circumferential gap .beta. is set to be large, so that radial misalignment
of the cup 109 is mainly accommodated by the inner circumferential
gap .beta.. However, when the inner circumferential gap .beta. is
set to be large, a radial gap formed between the stator 111 and
the plunger 102 becomes large, and a coil included in the solenoid
108 needs a large number of internal winding to obtain sufficient
magnetic performance. Accordingly, the valve actuator 103 is apt
to be jumboized.
[0009] According to JP-A-2000-193120, a stator 111 and an attachment
bracket 112 are integrally formed, so that the stator 111 is directly
secured to an external portion of the hydraulic device. However,
even when the stator 111 is directly fixed to an external portion
of the hydraulic device, radial misalignment of the cup 109 cannot
be accommodated.
SUMMARY OF THE INVENTION
[0010] In view of the foregoing problem, it is an object of the
present invention to provide a solenoid actuator, in which radial
misalignment between a stator and a cup can be accommodated even
a radial gap formed therebetween is small, and magnetic force generated
by a solenoid can be axially transferred efficiently between the
stator and the yoke. It is another object of the present invention
to provide a solenoid valve including the solenoid actuator.
[0011] According to the present invention, a solenoid actuator
includes a solenoid, a plunger, a stator, a cylindrical cup, a cylindrical
yoke, and a magnetic force transferring member. The solenoid generates
a magnetic force. The plunger is substantially coaxially received
in the solenoid to receive the magnetic force. The stator has a
substantially annular shape defining an inner circumferential face.
The cylindrical cup is received in the inner circumferential face
of the stator. The cylindrical cup receives the plunger, such that
the plunger is substantially axially slidable in the cup. The cylindrical
yoke radially surrounds the solenoid and an outer circumference
of the stator. The magnetic force transferring member is axially
inserted between a step portion formed in an inner circumference
of the yoke and the stator to axially transfer magnetic force between
the yoke and the stator. The outer circumference of the stator radially
forms a first gap with an inner circumferential face of the yoke
therebetween. The inner circumferential face of the stator radially
forms a second gap with an outer circumferential face of the cup
therebetween, The first gap is greater than the second gap. A solenoid
valve includes the solenoid actuator and a valve body. The valve
body connects to the plunger, such that the valve body is axially
actuated by the plunger to open and close a fluid channel. The stator,
the yoke and the plunger forms a magnetic circuit to magnetically
attract the plunger.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The above and other objects, features and advantages of
the present invention will become more apparent from the following
detailed description made with reference to the accompanying drawings.
In the drawings:
[0013] FIG. 1 is a cross-sectional side view showing a solenoid
valve according to an embodiment of the present invention;
[0014] FIG. 2 is a front view of an attachment bracket according
to the embodiment of the present invention;
[0015] FIG. 3 is a cross-sectional view showing radial gaps between
a cup, stator and a yoke according to the embodiment;
[0016] FIG. 4 is a cross-sectional side view showing a solenoid
valve according to a prior art; and
[0017] FIG. 5 is a cross-sectional view showing radial gaps between
a cup, stator and a yoke according to a related art.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0018] (First Embodiment)
[0019] A solenoid actuator (actuator portion) 5 including a solenoid
2 is provided in a solenoid valve 1. When the solenoid is energized,
the solenoid 2 generates magnetic force (attractive force) to actuate
a spool 3 serving as a valve body in the solenoid valve 1. The solenoid
valve 1 is incorporated into a hydraulic device 200 for providing
timing control to a controllable valve of an internal combustion
engine (not shown), for example. The solenoid valve 1 is used to
control the communication between the fluid channels 300 in the
hydraulic device 200.
[0020] As shown in FIG. 1, the solenoid valve 1 includes a valve
body portion 4 and the actuator portion 5. The valve body portion
4 is inserted into the hydraulic device 200 to communicate with
fluid channels 300. The valve body portion 4 accommodates the spool
3 for switching the fluid communication in the fluid channels. The
actuator portion 5, which is secured externally to the hydraulic
device 200, accommodates a plunger 6 for actuating the spool 3,
and the solenoid 2 energized for generating magnetic force (attractive
force) to actuate the plunger 6. In the explanations below, the
"front" and "rear," and the "up" and
"down" will be referred to with respect to the arrangement
shown in FIG. 1.
[0021] The valve body portion 4 includes a cylindrical sleeve 8,
the spool 3, and a spring 9. The cylindrical sleeve 8 has multiple
ports 7 to be communicated to the fluid channels. The spool 3 slidably
moves along the inner circumferential portion of the sleeve 8 thereby
opening or closing the group of ports 7. The spring 9 resiliently
biases the spool 3 in a direction, in which the spool 3 is pushed
out of the sleeve 8.
[0022] The spool 3 is a cylindrical valve body, in which a cylindrical
hollow portion 11 with its front end face forming an opening 10
is formed in the major axis direction of the spool 3 (axial direction).
The spool 3 has a wide circumferential groove 12 substantially at
the outer circumferential face in the axial direction. Furthermore,
through-holes 13 and 14, which respectively penetrate the outer
circumferential face of the spool 3 vertically toward the hollow
portion 11, are formed at the upper and lower positions of the spool
3 with respect to the major axis of the spool 3. The through-holes
13 and 14 are formed at the front and rear positions axially substantially
symmetric with respect to the circumferential groove 12. The opening
10 and the spring 9 are coaxially located with respect to the major
axis of the spool 3. A contact portion 15 of the spool 3 in contact
with the plunger 6 extends backward from the rear end face of the
spool 3.
[0023] The sleeve 8 is a cylindrical valve housing, which accommodates
the spool 3 moving slidably back and forth. The sleeve 8 has an
opening 16 at the front end face, which axially faces the opening
10 of the spool 3. Three circumferential grooves 17, 18, and 19
are formed in the inner circumferential face of the sleeve 8. The
ports 20, 21, and 22 vertically penetrate the outer circumferential
face of the sleeve 8, and communicate to the circumferential grooves
17, 18, and 19, respectively. That is, the ports 20 and 22 penetrating
the outer circumferential face of the sleeve 8 from below (down
side) respectively communicate to the circumferential grooves 17
and 19, and the port 21 penetrating the outer circumferential face
of the sleeve 8 from above (up side) communicate to the circumferential
groove 18. The port 20 mainly communicates to the through-hole 13,
the port 21 mainly communicates to the circumferential groove 12,
and the port 22 mainly communicates to the through-hole 14. The
circumferential groove 12 of the spool 3 is wide enough in the axial
direction (front to rear), so that the circumferential grooves 17
and 18 or the circumferential grooves 18 and 19 communicate with
each other. The sleeve 8 has a flange portion 23 at the rear end
portion thereof. The flange portion 23 is greater in diameter than
the cylindrical portion of the sleeve 8, in which the ports 20,
21, and 22 are formed. The ports 20, 21, and 22 are connected to
a fluid channels 300 which are externally connected to the solenoid
valve 1. The flange portion 23 has a shoulder portion on the outer
circumferential edge on the front end face of the flange portion
23. The front end portion of a yoke 24 is engageably crimped to
the shoulder portion of the flange portion 23. The flange portion
23 has an O-ring 25 on the inner circumference side of the flange
portion 23.
[0024] The actuator portion 5 includes the solenoid 2, the plunger
6, a cup 26, and an attachment bracket 27. The solenoid 2 is energized
to generate magnetic force in accordance with a signal transmitted
from an engine control unit (electronic control unit, ECU, not shown).
The plunger 6 actuates the spool 3 by the magnetic force generated
by the solenoid 2. The cup 26 slidably sustains the plunger 6. The
attachment bracket 27 secures the actuator portion 5 externally
to the hydraulic device 200. A magnetic circuit created by energizing
the solenoid 2 is mainly formed among the plunger 6, the yoke 24
for accommodating the solenoid 2, and a stator 28 for magnetically
coupling, i.e., transferring the magnetic force between the yoke
24 and the plunger 6. The yoke 24 and the stator 28 also form part
of the actuator portion 5.
[0025] The solenoid 2 has a cylindrical body that includes a coil
29 that are wound at predetermined intervals in the axial direction,
and a resinous portion (plastic portion) 30, in which the coil 29
is embedded. The outer circumferential face and the rear end face
of the solenoid 2 are covered with the cylindrical yoke 24, and
the front end face of the solenoid 2 is covered with the stator
28. The outer circumferential face of the stator 28 is also covered
with the cylindrical yoke 24. The solenoid 2 has a shoulder portion
31 on the outer circumferential edge of the front end face of the
solenoid 2, and a tapered portion 32 on the inner circumferential
edge of the solenoid 2 to be reduced in diameter toward the rear
side thereof. The coil 29 is connected to the ECU via a connector
terminal pin 33.
[0026] The yoke 24 is mainly formed of a large diameter portion
34 and a small diameter portion 35. The large diameter portion 34
of the yoke 24 covers the outer circumference of the solenoid 2.
The small diameter portion 35 of the yoke 24, which is coupled with
the plunger 6 each other, supports the rear end side of the cup
26. Specifically, the small diameter portion 35 of the yoke 24 and
the plunger 6 transfers magnetic force with each other. The large
diameter portion 34 of the yoke 24 has a step portion 36 on the
inner circumference at the front end portion of the large diameter
portion 34. Furthermore, the large diameter portion 34 of the yoke
24 has a crimped portion 37 that is engageably crimped to the flange
portion 23 of the sleeve 8 at the front portion, i.e., front end
portion of the yoke 24. Thus, the valve body portion 4 and the actuator
portion 5 are integrated with each other.
[0027] The stator 28 is disposed close to the front end of the
solenoid 2 to form a magnetic circuit between the yoke 24 and the
plunger 6. The stator 28 is a substantially annular flat plate that
has a predetermined width in the radial direction thereof. A cylinder
portion 38 of the cup 26 is inserted into the inner circumferential
portion of the stator 28 from the front side thereof, so that a
rear end face of a collar portion 39 contacts the front end face
of the stator 28 with each other. A cylindrical core portion 40
protrudes backward, i.e., toward rear side thereof from the inner
circumferential edge of the stator 28. The outer circumferential
face of the core portion 40 of the stator 28 is tapered to reduce
in diameter toward the rear side and fitted into the tapered portion
32 of the solenoid 2. Thus, the stator 28 and the plunger 6 axially
transfers magnetic force with each other. This arrangement further
ensures that the stator 28 and the plunger 6 are magnetically coupled
to each other. A gap is formed in the axial direction between the
rear end face of the stator 28 and the front end face of the solenoid
2, thereby accommodating tolerances of the respective components.
[0028] As shown in FIGS. 1 and 2, the attachment bracket 27 includes
a fixed portion 41 to be secured to an external predetermined position
of the hydraulic device 200, and a restrained portion 42 to be restrained
within the yoke 24 of the solenoid valve 1. The restrained portion
42 serves as a magnetic force transferring member. The fixed portion
41 is screwed onto the hydraulic device 200, so that the actuator
portion 5 is secured externally to the hydraulic device 200. As
shown in FIG. 2, the fixed portion 41, which has a flat plate shape,
includes an insertion hole 43 into which a bolt (not shown) or the
like is inserted.
[0029] The restrained portion 42 is annular in shape with a predetermined
width in the radial direction. The restrained portion 42 is fitted
over the step portion 36 of the yoke 24, and axially inserted between
the step portion 36 of the yoke 24 and the rear end face of a circumferentially,
i.e., radially outer portion of the stator 28, so that the restrained
portion 42 is restrained in the yoke 24 of the solenoid valve 1.
The restrained portion 42 is axially inserted between the step portion
36 of the yoke 24 and the rear end face of the radially outer portion
of the stator 28, so that the restrained portion 42 serves as a
magnetic force transferring member to transfer magnetic force between
the yoke 24 and the stator 28.
[0030] The attachment bracket 27 is a separate member from the
stator 28, and the front end face of the restrained portion 42 of
the attachment bracket 27 contacts the rear end face of the stator
28. With this arrangement, the outer circumferential face of the
restrained portion 42 closely contacts the inner circumferential
face of the yoke 24, and the inner circumferential face of the restrained
portion 42 faces the outer circumferential face of the shoulder
portion 31 of the solenoid 2 with a predetermined gap therebetween.
The fixed portion 41 and the restrained portion 42 are substantially
parallel to each other and connected to each other by means of a
coupling portion 44. As shown in FIG. 1, the attachment bracket
27 is assembled to the solenoid valve 1, so that the fixed portion
41 of the attachment bracket 27 is positioned at the front side
compared with the restrained portion 42.
[0031] The plunger 6 has a pillar-shaped body, which contacts the
contact portion 15 of the spool 3, and coaxially arranged with the
center axis of the solenoid 2 to receive magnetic forces, thereby
axially actuating the spool 3. The center axis of the solenoid 2
is coaxial with respect to the major axis of the spool 3. The plunger
6 has an air vent hole 45 that penetrates in the axial direction,
allowing air or liquid to enter to or exit from the rear end portion
of the cup 26 as the plunger 6 moves.
[0032] The cup 26 has the cylinder portion 38 that is coaxially
arranged in the inner circumference of the solenoid 2, and the collar
portion 39 that radially extends outwardly from the outer circumference
of front end side of the cylinder portion 38. The cylinder portion
38 is closed, i.e., bottomed at its rear end, and opened at its
front end, thereby allowing the rear end portion of the spool 3
to move freely back and forth therethrough. The cylinder portion
38 retains the plunger 6, such that the plunger 6 can move back
and forth in the cylinder portion 38. That is, the outer circumferential
face of the plunger 6 slides back and forth with respect to the
inner circumferential face of the cylinder portion 38. The cup 26
prevents the plunger 6 from backwardly protruding out of the cylinder
portion 38 of the cup 26 due to hydraulic pressure. That is, the
rear end face of the plunger 6 contacts the rear bottomed end of
the cylinder portion 38 of the cup 26, thereby preventing the plunger
6 from backwardly dropping off. The collar portion 39 is disposed
closer to the front side inside the yoke 24 of the solenoid valve
1 than the restrained portion 42 of the attachment bracket 27, and
sandwiched between the O-ring 25 and the front end face of the stator
28. That is, the collar portion 39 is disposed on an axially opposite
side as the solenoid 2 with respect to the restrained portion 42.
[0033] As shown in FIG. 3, with the solenoid valve 1, an outer
circumferential gap .alpha. is radially formed between the inner
circumferential face of the yoke 24 and the outer circumferential
face of the stator 28. Besides, an inner circumferential gap .beta.
is radially formed between the outer circumferential face of the
cylinder portion 38 of the cup 26 and the inner circumferential
face of the stator 28. The outer circumferential gap .alpha. is
greater than the inner circumferential gap .beta..
[0034] (Operation of First Embodiment)
[0035] The operation of the solenoid valve 1 is explained as below.
First, the coil 29 of the solenoid 2 is energized in response to
a signal from the ECU, so that magnetic force is generated to actuate
the plunger 6. The plunger 6 slides inside the cylinder portion
38 of the cup 26, so that the spool 3 in contact with the plunger
6 is actuated to axially slide in the sleeve 8. The coil 29 is energized,
and magnetic force is generated by the coil 29, so that the plunger
6 moves frontward. This results in the spool 3 being actuated to
move frontward against the resilient force of the spring 9. Conversely,
when electric power applied to the coil 29 decreases, magnetic force
generated by the coil 29 becomes small, so that the spool 3 urged
by the spring 9 moves backwardly, and the plunger 6 in contact with
the spool 3 moves backwardly. In this manner, each port of the valve
body portion 4 opens or closes, so that communication in the fluid
channels connected to each ports is controlled.
[0036] (Features and Effects of First Embodiment)
[0037] In this embodiment, with the solenoid valve 1, the restrained
portion 42 of the attachment bracket 27 is axially inserted between
the step portion 36 formed in the inner circumferential face of
the yoke 24 and the circumferentially, i.e., radially outer portion
of the stator 28, so that the restrained portion 42 serves as the
magnetic force transferring member to axially transfer magnetic
force between the yoke 24 and the stator 28. The cup 26 fits into
the inner circumferential face of the stator 28 from the front side,
and the outer circumferential gap (first gap) .alpha. is set to
be greater than the inner circumferential gap (second gap) .beta..
Therefore, even when the inner circumferential gap .beta. is set
to be small, radial misalignment of the cup 26 can be accommodated
by the outer circumferential gap .alpha.. The restrained portion
42 serves as the magnetic force transferring member, so that the
yoke 24 and the stator 28 can axially transfer magnetic force with
each other, efficiently. As a result, even when the inner circumferential
gap .beta. is set to be small to reduce the radial gap between the
solenoid 2 and the plunger 6, radial misalignment of the cup 26
can be accommodated by the outer circumferential gap .alpha., and
the yoke 24 and the stator 28 can axially transfer magnetic force
with each other, efficiently. Therefore, the radial gap between
the solenoid 2 and the plunger 6 can be reduced, so that an internal
winding number of the coil 29 of the solenoid 1 can be reduced,
thereby downsizing the actuator portion 5. Furthermore, radial misalignment
of the cup 26 can be accommodated by the outer circumferential gap
.alpha., so that the cup 26 can be restricted from deformation,
and the plunger 6 can be operated smoothly.
[0038] The step portion 36 of the yoke 24 and the restrained portion
42 of the attachment bracket 27 contact plane to plane with each
other, and the restrained portion 42 of the attachment bracket 27
and the stator 28 also contact plane to plane with each other. Therefore,
components, such as the yoke 24, the attachment bracket 27 and the
stator 28 can steadily connected with each other, and arrangement
of the components can be easily maintained, so that magnetic force
can be axially transferred in the magnetic circuit, steadily.
[0039] The attachment bracket 27 includes the fixed portion 41
to be secured externally to the hydraulic device 200, and the restrained
portion 42 to be restrained within the yoke 24 of the solenoid valve
1. Furthermore, the cup 26 includes the collar portion 39 that radially
extends outwardly from the outer circumference of the front end
portion of the cylinder portion 38 that slidably sustains the plunger
6. The collar portion 39 is disposed closer to the front side than
the restrained portion 42 inside the solenoid valve 1.
[0040] This arrangement ensures that the liquid pressure acting
from the front side of the spool 3 and the plunger 6 is conveyed
to the fixed portion 41 via the collar portion 39 and the restrained
portion 42. Therefore, the solenoid valve 1 is secured to the hydraulic
device 200, and prevented from dropping off the hydraulic device
200. This effect is particularly effective when the liquid pressure
directly acts axially to the solenoid valve 1 through the opening
16 of the sleeve 8 and the opening 10 of the spool 3.
[0041] The stator 28 is separated from the attachment bracket 27,
so that the stator 28 can used independently of the attachment bracket
27. Therefore, the stator 28 can be commonly used among different
types of solenoid valves, thereby improving productivity.
MODIFIED EXAMPLE
[0042] In the above embodiment, the actuator portion 5 having the
above structure is not limited to the use of a solenoid valve. The
actuator portion 5 can be applied to any other solenoid actuator
used for an actuating device, such as a positioning actuator, a
lock device, a relay device, a pumping apparatus, for example.
[0043] In the above embodiment, the solenoid valve 1 is incorporated
into a hydraulic device 200 that provides timing control to a controllable
valve in an internal combustion engine. However, the solenoid valve
1 can be also incorporated into a hydraulic device that controllably
actuates a multi-plate clutch or multi-plate brake in an automatic
transmission, for example.
[0044] In the above embodiment, the collar portion 39 of the cup
26, the stator 28, and the restrained portion 42 of the attachment
bracket 27 are disposed from front side to rear side. However, the
arrangement can be modified so long as the collar portion 39 is
placed on the front side than the restrained portion 42. For example,
the stator 28, the collar portion 39, and the restrained portion
42 may be disposed from the front side to rear side in that order.
[0045] The spool 3 and the plunger 6 can be formed in one piece,
and another shaft member can be additionally provided between the
spool 3 and the plunger 6.
[0046] The restrained portion 42 serving as the magnetic force
transferring member can be a separate member separated from the
attachment bracket 27.
[0047] Various modifications and alternations may be made to the
above embodiments without departing from the spirit of the present
invention. |