U.S. patent application number 15/633460 was filed with the patent office on 2017-12-28 for servo-valve and fluidic device.
This patent application is currently assigned to NABTESCO CORPORATION. The applicant listed for this patent is NABTESCO CORPORATION. Invention is credited to Satoshi ASADA, Keitaroh OHSHIO, Yu SHIBATA.
Application Number | 20170370496 15/633460 |
Document ID | / |
Family ID | 59239825 |
Filed Date | 2017-12-28 |
United States Patent
Application |
20170370496 |
Kind Code |
A1 |
OHSHIO; Keitaroh ; et
al. |
December 28, 2017 |
SERVO-VALVE AND FLUIDIC DEVICE
Abstract
Servo-valve that controls fluid discharged from a nozzle
discharge port by displacing the nozzle, and that drives an
actuator. The servo-valve includes a receiver having an inflow
surface provided with a first inflow port, and a second inflow port
into which fluid discharged from the discharge port flows. The
nozzle includes a force generation portion having an end surface
provided with the discharge port, and an outer circumferential
surface formed on the periphery of the end surface. Displacing the
nozzle from neutral position toward the first inflow port blows the
fluid inside the second inflow port out toward the nozzle. The
force generation portion collides with the fluid blown out from the
second inflow port, causing assisting force in a direction matching
the direction of nozzle displacement toward the first inflow port.
The nozzle easily moves by the assisting force generated in the
force generation portion, improving response speed.
Inventors: |
OHSHIO; Keitaroh; (Fuwa-gun,
JP) ; SHIBATA; Yu; (Fuwa-gun, JP) ; ASADA;
Satoshi; (Fuwa-gun, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NABTESCO CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
NABTESCO CORPORATION
Tokyo
JP
|
Family ID: |
59239825 |
Appl. No.: |
15/633460 |
Filed: |
June 26, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16K 11/072 20130101;
F16K 31/423 20130101; F15B 13/0436 20130101 |
International
Class: |
F16K 31/42 20060101
F16K031/42; F16K 11/072 20060101 F16K011/072 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 27, 2016 |
JP |
2016-126964 |
Jun 5, 2017 |
JP |
2017-111225 |
Claims
1. A servo-valve that controls a fluid discharged from a discharge
port of a nozzle by displacing the nozzle and drives an actuator,
servo-valve comprising: a receiver that includes an inflow surface
provided with a first inflow port and a second inflow port into
which the fluid discharged from the discharge port flows, wherein
the nozzle includes a force generation portion that includes an end
surface provided with the discharge port and an outer
circumferential surface formed in the periphery of the end surface,
wherein when the nozzle is displaced from a neutral position in
which an extended line extended from a center of the discharge port
intersects the inflow surface between the first inflow port and the
second inflow port toward a position in which the extended line
intersects the first inflow port, the fluid inside the second
inflow port is blown out toward the nozzle, and wherein the force
generation portion collides with the fluid blown out from the
second inflow port and causes an assisting force in a direction
matching the nozzle displacement direction.
2. The servo-valve according to claim 1, wherein when the nozzle is
displaced from the neutral position toward a position in which the
extended line intersects the second inflow port, the fluid inside
the first inflow port is blown out toward the nozzle, and wherein
the force generation portion collides with the fluid blown out from
the first inflow port and causes an assisting force in a direction
matching the nozzle displacement direction.
3. The servo-valve according to claim 2, wherein the force
generation portion is a cone which protrudes toward the inflow
surface and grows narrower toward the inflow surface, and wherein
the outer circumferential surface includes a first force generation
surface that causes an assisting force for the displacement of the
nozzle toward the first inflow port and a second force generation
surface that causes an assisting force for the displacement of the
nozzle toward the second inflow port.
4. The servo-valve according to claim 3, wherein the first force
generation surface faces the second inflow port, and wherein the
second force generation surface faces the first inflow port.
5. The servo-valve according to claim 3, wherein the nozzle
includes a facing surface that faces the inflow surface, wherein
the facing surface is formed within the first virtual plane,
wherein the cone includes a discharge end surface that is formed
within a second virtual plane defined between the first virtual
plane and the inflow surface and is provided with the discharge
port, wherein a first outline of the cone within the first virtual
plane is surrounded by an outer edge of the facing surface, and
wherein a second outline of the cone within the second virtual
plane surrounds the discharge port.
6. The servo-valve according to claim 5, wherein the first outline
forms a concave corner between the outer circumferential surface
and the facing surface.
7. The servo-valve according to claim 3, wherein the nozzle
includes a facing surface that faces the inflow surface, wherein
the facing surface is formed within the first virtual plane, and
wherein the first force generation surface and the second force
generation surface form a groove portion that is recessed from the
first virtual plane.
8. The servo-valve according to claim 5, wherein the outer edge is
formed at a position separated from each of the first inflow port
and the second inflow port in relation to a distance between the
first inflow port and the second force generation surface and a
distance between the second inflow port and the first force
generation surface.
9. The servo-valve according to claim 3, wherein the receiver
includes a first flow path wall that forms a first flow path
extended from the first inflow port and a second flow path wall
that forms a second flow path extended from the second inflow port,
wherein the inflow surface divides the fluid discharged from the
discharge port into a first fluid flowing into the first inflow
port and a second fluid flowing into the second inflow port, and
wherein when the nozzle is displaced from the neutral position
toward the first inflow port, the second fluid is reflected by the
second flow path wall toward the first force generation
surface.
10. The servo-valve according to claim 9, wherein when the nozzle
is displaced from the neutral position toward the second inflow
port, the first fluid is reflected by the first flow path wall
toward the second force generation surface.
11. The servo-valve according to claim 2, further comprising: a
driving unit that displaces the nozzle; and a casing that is
provided with a flow path through which the fluid flows, wherein
the casing is provided with a first outflow port connected to the
first inflow port and a second outflow port connected to the second
inflow port, and wherein the driving unit displaces the nozzle
between the first inflow port and the second inflow port to adjust
the amount of the fluid flowing out of the first outflow port and
the amount of the fluid flowing out of the second outflow port.
12. The servo-valve according to claim 11, further comprising: a
first movable piece that moves in a reciprocating manner inside the
casing by the fluid in response to the displacement of the nozzle,
wherein when the nozzle is displaced toward the first inflow port,
the first movable piece is displaced by the fluid discharged to the
first inflow port and extrudes the fluid from the second outflow
port to blow out the fluid from the second inflow port, and wherein
when the nozzle is displaced toward the second inflow port, the
first movable piece is displaced by the fluid discharged to the
second inflow port and extrudes the fluid from the first outflow
port to blow out the fluid from the first inflow port.
13. A fluidic device comprising: the servo-valve according to claim
12; and an actuator that includes a second movable piece operated
in response to the displacement of the first movable piece.
14. A fluidic device comprising: the servo-valve according to claim
11; an actuator that includes the casing and a movable piece
dividing a hollow portion formed by the casing to form the flow
path, wherein when the nozzle is displaced toward the first inflow
port, the movable piece is displaced by the fluid discharged to the
first inflow port and extrudes the fluid from the second outflow
port to blow out the fluid from the second inflow port, and wherein
when the nozzle is displaced toward the second inflow port, the
movable piece is displaced by the fluid discharged to the second
inflow port and extrudes the fluid from the first outflow port to
blow out the fluid from the first inflow port.
Description
RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from the prior Japanese Patent Application No.
2016-126964, filed on Jun. 27, 2016 and the prior Japanese Patent
Application No. 2017-111225, filed on Jun. 5, 2017, the entire
content of each of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention relates to a servo-valve and a fluidic
device having a high response performance.
2. Description of the Related Art
[0003] A servo-valve is used in airplanes or other industrial
fields. U.S. Pat. No. 2,884,907 discloses a technique of displacing
a nozzle toward left and right sides of a rotation axis based on an
electromagnetic principle to adjust the amount of hydraulic oil
flowing into two inflow ports formed in a receiver.
[0004] A high response speed of the servo-valve results in a high
accuracy of a control using the servo-valve. Thus, there have been
various attempts for improving a mechanical mechanism and/or an
electrical mechanism for driving the nozzle from the past. However,
many of these improvements face various problems involving with a
selection of a material, a mechanical strength, a complex control,
and a manufacturing cost of the servo-valve.
SUMMARY OF THE INVENTION
[0005] An object of the invention is to provide a simple technique
of giving a high response speed to a servo-valve.
[0006] A servo-valve according to an aspect of the invention
controls a fluid discharged from a discharge port of a nozzle by
displacing the nozzle and drives an actuator. The servo-valve
includes a receiver that includes an inflow surface provided with a
first inflow port and a second inflow port into which the fluid
discharged from the discharge port flows. The nozzle includes a
force generation portion that includes an end surface provided with
the discharge port and an outer circumferential surface formed in
the periphery of the end surface. When the nozzle is displaced from
a neutral position in which an extended line extended from a center
of the discharge port intersects the inflow surface between the
first inflow port and the second inflow port toward a position in
which the extended line intersects the first inflow port, the fluid
inside the second inflow port is blown out toward the nozzle. The
force generation portion collides with the fluid blown out from the
second inflow port and causes an assisting force in a direction
matching the nozzle displacement direction.
[0007] According to the above-described configuration, since the
force generation portion collides with the fluid blown out from the
second inflow port and causes an assisting force in a direction
matching the nozzle displacement direction, the displacement of the
nozzle is assisted by a first assisting force. Since the nozzle can
be quickly displaced toward the first inflow port under the action
of the assisting force, the servo-valve can quickly drive the
actuator.
[0008] A fluidic device according to another aspect of the
invention includes the above-described servo-valve and an actuator
that includes a second movable piece operated in response to the
displacement of a first movable piece.
[0009] According to the above-described configuration, since the
fluidic device includes the above-described servo-valve, the nozzle
is highly responsively operated. As a result, the first movable
piece can be also highly responsively displaced. Since the second
movable piece of the actuator is operated in response to the
displacement of the first movable piece, the second movable piece
can be also highly responsively operated.
[0010] A fluidic device according to still another aspect of the
invention includes the above-described servo-valve and an actuator
that includes the casing and a movable piece dividing a hollow
portion formed by the casing to form the flow path. When the nozzle
is displaced toward the first inflow port, the movable piece is
displaced by the fluid discharged to the first inflow port and
extrudes the fluid from the second outflow port to blow out the
fluid from the second inflow port. When the nozzle is displaced
toward the second inflow port, the movable piece is displaced by
the fluid discharged to the second inflow port and extrudes the
fluid from the first outflow port to blow out the fluid from the
first inflow port.
[0011] According to the above-described configuration, since the
movable piece is displaced by the fluid discharged to the first
inflow port and blows out the fluid from the second inflow port
when the nozzle is displaced toward the is first inflow port, the
displacement of the nozzle toward the first inflow port is assisted
by the fluid blown out from the second inflow port. Since the
movable piece is displaced by the fluid discharged to the second
inflow port and blows out the fluid from the first inflow port when
the nozzle is displaced toward the second inflow port, the
displacement of the nozzle toward the second inflow port is
assisted by the fluid blown out from the first inflow port.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a conceptual diagram showing a servo-valve
according to a first embodiment.
[0013] FIG. 2A is a conceptual diagram showing the servo-valve
shown in FIG. 1.
[0014] FIG. 2B is a conceptual diagram showing the servo-valve
shown in FIG. 1.
[0015] FIG. 3 is a conceptual diagram showing a servo-valve
according to a second embodiment.
[0016] FIG. 4 is a schematic cross-sectional view showing a nozzle
according to a third embodiment.
[0017] FIG. 5 is a schematic diagram showing four outlines formed
on the nozzle shown in FIG. 4.
[0018] FIG. 6 is a schematic cross-sectional view showing a nozzle
according to a fourth embodiment.
[0019] FIG. 7 is a conceptual diagram showing the servo-valve shown
in FIG. 1 (fifth embodiment).
[0020] FIG. 8A is a schematic enlarged view showing the servo-valve
shown in FIG. 1 (sixth embodiment).
[0021] FIG. 8B is a schematic enlarged view showing the servo-valve
shown in FIG. 1 (sixth embodiment).
[0022] FIG. 9 is a schematic diagram showing a fluidic device
according to a seventh embodiment.
[0023] FIG. 10 is a schematic diagram showing a fluidic device
according to an eighth embodiment.
[0024] FIG. 11A is a graph showing a relation among a relative
position of a nozzle with respect to a receiver, a flow rate of a
hydraulic fluid discharged from the nozzle, and a force applied
from a hydraulic fluid to the nozzle (ninth embodiment).
[0025] FIG. 11B is a graph showing a relation among a relative
position of a nozzle with respect to a receiver, a flow rate of a
hydraulic fluid discharged from the nozzle, and a force applied
from a hydraulic fluid to the nozzle (ninth embodiment).
[0026] FIG. 12 is a diagram describing a peripheral angle of the
nozzle of the embodiment.
[0027] FIG. 13 is a diagram showing a modified example of the
nozzle of the embodiment.
DETAILED DESCRIPTION OF THE INVENTION
[0028] The invention will now be described by reference to the
preferred embodiments. This does not intend to limit the scope of
the present invention, but to exemplify the invention.
First Embodiment
[0029] A servo-valve generally includes a receiver and a nozzle.
The receiver is provided with a pair of inflow ports into which a
hydraulic fluid (which is, for example, hydraulic oil and will be
simply referred to as a "fluid" while the invention is not limited
to the hydraulic oil) discharged from the nozzle flows. While the
hydraulic fluid discharged from the nozzle mainly flows into one
inflow port, the hydraulic fluid extruded by the spool valve or the
actuator is discharged from the other inflow port. The inventors
have developed a technique of improving the response performance of
the servo-valve by using the hydraulic fluid extruded by the spool
valve or the actuator. In the first embodiment, an illustrative
servo-valve having a satisfactory response will be described.
[0030] FIG. 1 is a conceptual diagram showing a servo-valve 100 of
a first embodiment. The servo-valve 100 will be described with
reference to FIG. 1. Terms like "upward," "downward," "leftward,"
"rightward," "clockwise," "counterclockwise," "vertical," and
"horizontal" indicating directions are used merely for the purpose
of making the explanation unambiguous. The principle of the
embodiments is not by any means limited by these terms denoting the
directions.
[0031] The servo-valve 100 includes a nozzle 200, a receiver 300,
and a driving unit 400. The driving unit. 400 turns (swings)
(hereinafter, referred to as "oscillation movement" or
"oscillation") a front end of the nozzle 200 in both directions
(clockwise and counterclockwise) within a predetermined angle range
about a rotation axis FAX defined at an upper portion of the nozzle
200. The driving unit 400 may be a general torque motor which gives
a rotational force (a turning force) to the nozzle 200 using an
electromagnetic force or other driving devices which turns (swings)
the front end of the nozzle 200 in both directions within a
predetermined angle range about a rotation axis. The principle of
the embodiment is not limited to a specific device used as the
driving unit 400.
[0032] The nozzle 200 includes an upper surface 210 and a lower
surface 220. The lower surface 220 faces the receiver 300. The
upper surface 210 is located above the lower surface 220. The upper
surface 210 is provided with an inflow port 211. The inflow port
211 is connected to a pump or other fluid supply sources supplying
a hydraulic fluid. The hydraulic fluid (which will be referred to
as, for example, hydraulic oil, but may be simply referred to as a
"fluid" on the condition that the invention is not limited thereto)
flows into the nozzle 200 through the inflow port 211.
[0033] The lower surface 220 (the front end surface) is provided
with a discharge port 221. The nozzle 200 is provided with a nozzle
flow path 230 which extends downward from the inflow port 211 and
is coupled to the discharge port 221. The nozzle flow path 230
becomes narrow toward the discharge port 221. The hydraulic fluid
which flows from the inflow port 211 into the nozzle 200 flows
downward along the nozzle flow path 230 and is discharged from the
discharge port 221. Subsequently, the hydraulic fluid flows into
the receiver 300.
[0034] The receiver 300 includes an upper surface (an opposite
surface) 310 which faces the lower surface 220 of the nozzle 200.
The upper surface 310 is provided with a left inflow port 311 and a
right inflow port 312. Each of the left inflow port 311 and the
right inflow port 312 is formed to be larger than the discharge
port 221. The receiver 300 is provided with a left flow path 313
and a right flow path 314. The left flow path 313 extends leftward
and downward from the left inflow port 311 and is terminated at the
left outflow port 315. The right flow path 314 extends rightward
and downward from the right inflow port 312 and is terminated at
the right outflow port 316. The left outflow port 315 and the right
outflow port 316 are formed in an outer surface of the receiver 300
and are coupled to a spool valve (not shown) or an actuator (not
shown).
[0035] The nozzle 200 shown in FIG. 1 is positioned at the neutral
position. When the nozzle 200 is positioned at the neutral
position, the center axis of the nozzle flow path 230 (the axis
line connecting the center of the inflow port 211 and the center of
the discharge port 221) substantially matches the vertical line VL
passing through a midpoint of a line extended between the center of
the left inflow port 311 and the center of the right inflow port
312. When the nozzle 200 is positioned at the neutral position, the
hydraulic fluid discharged from the discharge port 221 flows in
substantially in the same quantity into the left inflow port 311
and the right inflow port 312. In the embodiment, the first inflow
port is exemplified by one of the left inflow port 311 and the
right inflow port 312. The second inflow port is exemplified by the
other of the left inflow port 311 and the right inflow port 312.
The inflow surface is exemplified by the upper surface 310 of the
receiver 300.
[0036] FIGS. 2A and 2B are conceptual diagrams of the servo-valve
100. Referring to FIGS. 1 to 2B, the servo-valve 100 will be
further described.
[0037] The nozzle 200 shown in FIG. 2A is oscillated clockwise
about the rotation axis RAX from the neutral position (the position
of the nozzle 200 shown in FIG. 1) by the driving unit 400. At this
time, the discharge port 221 is positioned to the left of the
vertical line VL.
[0038] The nozzle 200 shown in FIG. 2B is oscillated
counterclockwise about the rotation axis RAX from the neutral
position (the position of the nozzle 200 shown in FIG. 1) by the
driving unit 400. At this time, the discharge port 221 is
positioned to the right of the vertical line VL.
[0039] FIGS. 2A and 2B respectively show the discharge line DCL
extended from the center of the discharge port 221 toward the
receiver 300 in the extension direction of the center axis of the
nozzle flow path 230. The hydraulic fluid is discharged from the
discharge port 221 along the discharge line DCL. When the nozzle
200 is oscillated clockwise by the driving unit 400, the discharge
line DCL intersects the left inflow port 311 when the nozzle 200 is
oscillated counterclockwise by the driving unit 400, the discharge
line DCL intersects the right inflow port 312. In the embodiment,
the extended line is exemplified by the discharge line DCL. The
first position is exemplified by the position of the nozzle 200
shown in one of FIGS. 2A and 2B. The second position is exemplified
by the position of the nozzle 200 shown in the other of FIGS. 2A
and 2B.
[0040] The lower surface 220 of the nozzle 200 includes a facing
surface 222 which faces the upper surface 310 of the receiver 300
and a protruding surface 223 that protrudes downward from the
facing surface 222. When the nozzle 200 is positioned at the
neutral position (see FIG. 1), the facing surface 222 is
substantially parallel to the upper surface 310 of the receiver
300. The protruding surface 223 forms a projection protruding from
the facing surface 222. In the embodiment, the protruding surface
223 forms a truncated cone is which corresponds to a projection and
grows narrower toward the upper surface 310 of the receiver 300.
Alternatively, the protruding surface 223 may be configured as a
projection to form another three-dimensional shape (for example,
truncated pyramid or dome). The principle of the embodiment is not
limited to a specific three-dimensional shape formed by the
protruding surface 223. In the embodiment, a force generation
portion is exemplified by the protruding surface 223. That is, the
force generation portion is formed by a surface which is formed in
a direction generating a force of assisting the displacement of the
nozzle 200 by the fluid returning from the receiver 300.
[0041] The protruding surface 223 includes an end surface 224 and a
circumferential surface 225. The discharge port 221 is formed in
the end surface 224. The circumferential surface 225 is an annular
band surface formed between the end surface 224 and the facing
surface 222 and forms an outer circumferential surface having a
truncated cone form and formed by the protruding surface 223.
[0042] FIG. 2A shows the center line RCL of the right flow path
314. The center line Rot intersects the right half of the
circumferential surface 225.
[0043] The hydraulic fluid discharged from the nozzle 200 shown in
FIG. 2A mainly flows into the left inflow port 311. Subsequently,
the hydraulic fluid is supplied to a movable portion (not shown)
such as a spool valve (not shown) is or an actuator (not shown)
through the left flow path 313. The movable portion performs a
predetermined operation by the hydraulic fluid supplied through the
left flow path 313. All this while, the movable portion extrudes
the hydraulic fluid existing in a flow path (not shown) connected
to the right flow path 314 from the movable portion. As a result,
the hydraulic fluid is blown out from the right inflow port 312 to
the extension direction (the left obliquely upward direction) of
the center line RCL. Thus, the hydraulic fluid blown out from the
right inflow port 312 collides with the right half of the
circumferential surface 225. The collision between the hydraulic
fluid and the right half of the circumferential surface 225 results
in an assisting force of assisting the clockwise oscillation of the
nozzle 200. In the embodiment, one of the first assisting force and
the second assisting force is exemplified by the assisting force
produced by the collision between the hydraulic fluid and the right
half of the circumferential surface 225. One of the first force
generation surface and the second force generation surface is
exemplified by the right half of the circumferential surface
225.
[0044] FIG. 2B shows the center line LCL of the left flow path 313.
The center line LCL intersects the left half of the circumferential
surface 225.
[0045] The hydraulic fluid discharged from the nozzle 200 shown in
FIG. 2B mainly flows into the right inflow port 312. Subsequently,
the hydraulic fluid is supplied to a movable portion (not shown)
such as a spool valve (not shown) or an actuator (not shown)
through the right flow path 314. The movable portion performs a
predetermined operation by the hydraulic fluid supplied through the
right flow path 314. All this while, the movable portion extrudes
the hydraulic fluid existing in a flow path (not shown) connected
to the left flow path 313 from the movable portion. As a result,
the hydraulic fluid is blown out from the left inflow port 311 to
the extension direction (the right obliquely upward direction) of
the center line LCL. Thus, the hydraulic fluid blown out from the
left inflow port 311 collides with the left half of the
circumferential surface 225. The collision between the hydraulic
fluid and the left half of the circumferential surface 225 results
in an assisting force of assisting the counterclockwise oscillation
of the nozzle 200. In the embodiment, the other of the first
assisting force and the second assisting force is exemplified by an
assisting force produced by the collision between the hydraulic
fluid and the left half of the circumferential surface 225. The
other of the first force generation surface and the second force
generation surface is exemplified by the left half of the
circumferential surface 225.
Second Embodiment
[0046] If the servo-valve can obtain the assisting force from the
hydraulic fluid blown out from the receiver immediately after the
movement from the neutral position, the response performance of the
servo-valve is further improved. In a second embodiment, an
illustrative servo-valve which is designed to obtain the assisting
force from the hydraulic fluid blown out from the receiver
immediately after the movement from the neutral position will be
described.
[0047] FIG. 3 is a conceptual diagram showing a servo-valve 100A of
the second embodiment. Referring to FIG. 3, the servo-valve 100A
will be described. The explanation of the first embodiment is
incorporated in the description of the elements denoted by the same
reference numerals as those of the first embodiment. In the
embodiment, terms like "upward," "downward," "leftward,"
"rightward," "clockwise," "counterclockwise," "vertical," and
"horizontal" indicating directions are used merely for the purpose
of making the explanation unambiguous. The principle of the
embodiments is not by any means limited by these terms denoting the
directions.
[0048] Like the first embodiment, the servo-valve 100A includes a
driving unit 400. The explanation of the first embodiment is
incorporated in the description of the driving unit 400.
[0049] The servo-valve 100A further includes a nozzle 200A and a
receiver 300A. Like the first embodiment, the nozzle 200A includes
the upper surface 210. Like the first embodiment, the nozzle flow
path 230 is formed inside the is nozzle 200A. The explanation of
the first embodiment is incorporated in the description of the
upper surface 210 and the nozzle flow path 230.
[0050] The nozzle 200A further includes a lower surface 220A. Like
the first embodiment, the lower surface 220A includes the facing
surface 222. The explanation of the first embodiment is
incorporated in the description of the facing surface 222.
[0051] The nozzle 200A further includes a protruding surface 223A
that protrudes downward from the facing surface 222. The protruding
surface 223A forms a projection which protrudes from the facing
surface 222. In the embodiment, the protruding surface 223A forms a
projection which is formed in a truncated cone form and grows
narrower toward an upper surface 310A of the receiver 300A.
Alternatively, the protruding surface 223A may be provided with a
projection having a different three-dimensional shape (for example,
a truncated pyramid or a dome). The principle of the embodiment is
not limited to a specific three-dimensional shape formed by the
protruding surface 223A. In the embodiment, the force generation
portion is exemplified by the protruding surface 223A.
[0052] The protruding surface 223A includes an end surface 224A and
a circumferential surface 225A. The discharge port 221 described in
the first embodiment is formed in the end surface 224A. The
circumferential surface 225A is an annular band surface which is
formed between the end surface 224A and the facing surface 222 and
forms an outer circumferential surface having a truncated cone form
and formed by the protruding surface 223A.
[0053] The receiver 300A includes an upper surface 310A which faces
the lower surface 220A of the nozzle 200A. The upper surface 310A
is provided with a left inflow port 311A and a right inflow port
312A. Each of the left inflow port 311A and the right inflow port
312A may be formed to be larger than the discharge port 221. The
receiver 300A is provided with a left flow path 313A and a right
flow path 314A. The left flow path 313A extends leftward and
downward from the left inflow port 311A and is terminated at the
left outflow port 315A. The right flow path 314A extends rightward
and downward from the right inflow port 312A and is terminated at
the right outflow port 316A. The left outflow port 315A and the
right outflow port 316A are formed in the outer surface of the
receiver 300A and are coupled to the spool valve (not shown) or the
actuator (not shown).
[0054] The nozzle 200A shown in FIG. 3 is positioned at the neutral
position. The left inflow port 311A of the receiver 300 faces a
wide area of the left half of the circumferential surface 225A of
the nozzle 200A at the neutral position. Thus, the nozzle 200A can
receive the assisting force of assisting the counterclockwise
oscillation from the hydraulic fluid blown out from the left inflow
port 311A almost simultaneously with the start of the
counterclockwise oscillation of the nozzle 200A. This means that
the nozzle 200A can be highly responsively oscillated
counterclockwise. The right inflow port 312A of the receiver 300
faces a wide area of the right half of the circumferential surface
225A of the nozzle 200A at the neutral position. Thus, the nozzle
200A can receive the assisting force of assisting the clockwise
oscillation from the hydraulic fluid blown out from the right
inflow port 312A almost simultaneously with the start of the
clockwise oscillation of the nozzle 200A. This means that the
nozzle 200A can be highly responsively oscillated clockwise.
[0055] In the embodiment, the first force generation surface is
exemplified by the left half or the right half of the
circumferential surface 225A of the nozzle 200A. The second force
generation surface is exemplified by the right half or the left
half of the circumferential surface 225A of the nozzle 200A. The
first inflow port is exemplified by the right inflow port 312A or
the left inflow port 311A. The second inflow port is exemplified by
the left inflow port 311A or the right inflow port 312A.
[0056] In order to obtain the above-described positional relation
among the left inflow port 311A, the right inflow port 312A, and
the circumferential surface 225A, the designer can adjust, for
example, the following dimensions.
[0057] (1) Distance between facing surface 222 and end surface
224A
[0058] (2) Size of end surface 224A
[0059] (3) Inclination angle between vertical line VL and
generation line of circumferential surface 225A (that is, taper
angle of truncated cone formed by protruding surface 223)
[0060] (4) Distance between centers of left inflow port 311A and
right inflow port 312A
[0061] (5) Shapes and sizes of left inflow port 311A and right
inflow port 312A
[0062] (6) Inclination angles of left flow path 313A and right flow
path 314A with respect to vertical line VL
Third Embodiment
[0063] The protruding surface of the nozzle described in the
above-described embodiments forms a truncated conical projection.
However, the projection may have various different forms. In a
third embodiment, an illustrative three-dimensional shape formed by
the protruding surface will be described.
[0064] FIG. 4 is a schematic cross-sectional view showing a nozzle
200B of the third embodiment. Referring to FIG. 4, the nozzle 200B
will be described. The explanation of the first embodiment is
incorporated in the description of the elements denoted by the same
reference numerals as those of the first embodiment. In the
embodiment, terms like "upward," "downward," "leftward,"
"rightward," "clockwise," "counterclockwise," "vertical," and
"horizontal" indicating directions are used merely for the purpose
of making the explanation unambiguous. The principle of the
embodiments is not by any means limited by these terms denoting the
directions.
[0065] Like the first embodiment, the nozzle 200B includes the
upper surface 210. Like the first embodiment, the nozzle flow path
230 is formed inside the nozzle 200B. The explanation of the first
embodiment is incorporated in the description of the upper surface
210 and the nozzle flow path 230.
[0066] The nozzle 200B further includes a lower surface 220B. Like
the first embodiment, the lower surface 220B includes the facing
surface 222. The explanation of the first embodiment is
incorporated in the description of the facing surface 222.
[0067] The lower surface 220B further includes a protruding surface
223B that protrudes downward from the facing surface 222. The
protruding surface 223B forms a projection which protrudes from the
facing surface 222.
[0068] FIG. 4 shows two horizontal planes HF1 and HF2. The
horizontal plane HF1 is a virtual plane following the facing
surface 222. The horizontal plane HF2 is a virtual plane which is
defined between the horizontal plane HF1 and an upper surface (not
shown) of a receiver (not shown). In the embodiment, a first
virtual plane is exemplified by the horizontal plane HF1. A second
virtual plane is exemplified by the horizontal plane HF2.
[0069] The protruding surface 223B includes an end surface 224B and
a circumferential surface 225B. The end surface 224B follows the
horizontal plane HF2. The discharge port 221 described in the first
embodiment is formed in the end surface 224B. The circumferential
surface 225B is a band surface which is formed between the end
surface 224B and the facing surface 222 and forms an outer
circumferential surface of a cone formed by the protruding surface
223B. In the embodiment, a discharge end surface is exemplified by
the end surface 224B.
[0070] FIG. 5 shows four outlines CT1, CT2, CT3, and CT4 formed on
the nozzle 200B. Referring to FIGS. 4 and 5, the nozzle 200B will
be further described.
[0071] The outline CT1 shows an outer edge of the facing surface
222 on the horizontal plane HF1. The outline CT2 shows an outline
of the circumferential surface 225B on the horizontal plane HF1.
The outline CT2 shows a concave corner formed by the facing surface
222 and the circumferential surface 225B. The outline CT2 is
surrounded by the outline CT1 as a whole. The outline CT3 shows an
outline of the end surface 224B on the horizontal plane HF2. The
outline CT3 is surrounded by the outline CT2 as a whole. The
outline CT4 shows an outline of the discharge port 221 on the
horizontal plane HF2. The outline CT4 is surrounded by the outline
CT3 as a whole. In the embodiment, a first outline is exemplified
by the outline CT2. A second outline is exemplified by the outline
CT3.
[0072] In the embodiment, the protruding surface 223B forms a
quadrangular pyramid. However, the protruding surface 223B may form
other three-dimensional forms (for example, an elliptical cone and
a hexagonal cone) if the relation of the above-described outline
holds. The principle of the embodiment is not limited to a specific
three-dimensional shape formed by the protruding surface 223B.
Fourth Embodiment
[0073] The protruding surface of the nozzle described in the third
embodiment forms a three-dimensional shape protruding from a facing
surface. Alternatively, the protruding surface of the nozzle may
form a part of a wall surface forming an outline of a groove
portion recessed from the facing surface. In a fourth embodiment, a
nozzle including a protruding surface forming a part of the wall
surface forming the outline of the groove portion recessed from the
facing surface will be described.
[0074] FIG. 6 is a schematic cross-sectional view showing a nozzle
200C of the fourth embodiment. Referring to FIG. 6, the nozzle 200C
will be described. The explanation of the third embodiment is
incorporated in the description of the elements denoted by the same
reference numerals as those of the third embodiment. In the
embodiment, terms like "upward," "downward," "leftward,"
"rightward," "clockwise," "counterclockwise," "vertical," and
"horizontal" indicating directions are used merely for the purpose
of making the explanation unambiguous. The principle of the
embodiments is not by any means limited by these terms denoting the
directions.
[0075] Like the third embodiment, the nozzle 200C includes the
upper surface 210. Like the third embodiment, the nozzle flow path
230 is formed inside the nozzle 200C. The explanation of the third
embodiment is incorporated in the description of the upper surface
210 and the nozzle flow path 230.
[0076] The nozzle 200C further includes a lower surface 220C. Like
the third embodiment, the lower surface 2200 includes the facing
surface 222. The explanation of the third embodiment is
incorporated in the description of the facing surface 222.
[0077] The lower surface 220C is provided with a groove portion 226
which is recessed from the facing surface 222. The lower surface
2200 further includes a protruding surface 223C which is surrounded
by the groove portion 226. The protruding surface 223C forms a
projection which protrudes downward from the bottom of the groove
portion 226.
[0078] FIG. 6 shows a virtual horizontal plane HF which follows the
facing surface 222. In the embodiment, a first virtual plane is
exemplified by the horizontal plane HF.
[0079] The protruding surface 2230 includes an end surface 224C and
a circumferential surface 225C. The discharge port 221 according to
the third embodiment is formed in the end surface 224C. In the
embodiment, the end surface 224C is flush with the horizontal plane
HF. Alternatively, the end surface may be positioned above or below
the horizontal plane HF. The principle of the embodiment is not
limited to a specific positional relation between the end surface
and the horizontal plane HF.
[0080] The circumferential surface 225C is a band surface which is
formed between the end surface 224C and the bottom of the groove
portion 226 and forms an outer circumferential surface of a cone
formed by the protruding surface 2230. The circumferential surface
2250 forms a part of the outline of the groove portion 226. As
described in the first embodiment, when the nozzle 200C is
oscillated clockwise, the right half of the circumferential surface
225C collides with the hydraulic fluid blown out from the right,
inflow port (riot shown) of the receiver (not shown). When the
nozzle 200C is oscillated counterclockwise, the left half of the
circumferential surface 2250 collides with the hydraulic fluid
blown out from the left inflow port (not shown) of the receiver
(not shown). In the embodiment, a first force generation surface is
exemplified by the right, half or the left half of the
circumferential surface 225C. A second force generation surface is
exemplified by the left half or the right half of the
circumferential surface 225C.
Fifth Embodiment
[0081] The hydraulic fluid blown out from the left inflow port or
the right inflow port of the receiver flows outward through a
narrow gap formed between the facing surface of the nozzle and the
upper surface of the receiver. There is a case an which a part of
the hydraulic fluid flowing from the outer edge of the facing
surface from the hydraulic fluid flows in the vicinity of the outer
circumferential surface of the nozzle and is separated from the
outer circumferential surface of the nozzle. The separation of the
hydraulic fluid from the outer circumferential surface of the
nozzle causes a force in a direction opposite to the nozzle
movement direction. In order to reduce a drag acting on the outer
circumferential surface of the nozzle as a result of the separation
of the hydraulic fluid, it is desirable that the hydraulic fluid
flowing through a narrow gap formed between the facing surface of
the nozzle and the upper surface of the receiver be sufficiently
straightened. In a fifth embodiment, an illustrate technique of
straightening the hydraulic fluid will be described.
[0082] FIG. 7 is a conceptual diagram of the servo-valve 100. The
explanation of the first embodiment is incorporated in the
description of the servo-valve 100. Referring to FIG. 7, the
servo-valve 100 will be described. In the embodiment, terms like
"upward," "downward," "leftward," "rightward," "clockwise,"
"counterclockwise," "vertical," and "horizontal" indicating
directions are used merely for the purpose of making the
explanation unambiguous. The principle of the embodiments is not by
any means limited by these terms denoting the directions.
[0083] The nozzle 200 shown in FIG. 7 is positioned at the neutral
position. FIG. 7 shows the vertical line VL, the center point LCP
of the left inflow port 311, and the center point RCP of the right
inflow port 312. FIG. 7 shows the cross-sections of the nozzle 200
and the receiver 300 on the virtual plane enclosing the center
points LCP and RCP and the vertical line VL.
[0084] FIG. 7 shows two points LIP and RIP of intersection which
are defined by the boundary line between the facing surface 222 and
the protruding surface 223 and the above-described virtual plane.
FIG. 7 further shows two points LOP and ROP of intersection which
are defined by the outer edge of the facing surface 222 and the
above-described virtual plane. FIG. 7 shows four vectors A, B, C,
and D. The vector A extends from the center point LCP to the point
LIP of intersection. The vector B extends from the center point LCP
to the point LOP of intersection. The vector C extends from the
center point RCP to the point RIP of intersection. The vector D
extends from the center point RCP to the point ROP of intersection.
The designer who designs the nozzle 200 may determine the outline
form of the facing surface 222 so that a relation shown in the
following inequality holds.
Min ( B .fwdarw. , D .fwdarw. ) > Max ( A .fwdarw. , C .fwdarw.
) Min ( B .fwdarw. , D .fwdarw. ) = B .fwdarw. if B .fwdarw.
.ltoreq. D .fwdarw. Min ( B .fwdarw. , D .fwdarw. ) = D .fwdarw. if
B .fwdarw. > D .fwdarw. Max ( A .fwdarw. , C .fwdarw. ) = A
.fwdarw. if A .fwdarw. .gtoreq. D .fwdarw. Max ( A .fwdarw. , C
.fwdarw. ) = C .fwdarw. if A .fwdarw. < C .fwdarw. Expression 1
##EQU00001##
[0085] if the relation of the above-described inequality holds, the
outer edge of the facing surface 222 is formed at a position
separated from each of the left inflow port 311 and the right
inflow port 312 in relation to a distance between the left inflow
port 311 and the left half of the circumferential surface 225 of
the protruding surface 223 and a distance between the right inflow
port 312 and the right half of the circumferential surface 225 of
the protruding surface 223. When a difference value DFV determined
by the following expression is large, the hydraulic fluid is
sufficiently straightened while flowing through a gap between the
facing surface 222 of the nozzle 200 and the upper surface 310 of
the receiver 300. The designer may determine the outline form of
the facing surface 222 to obtain a large difference value DFV.
DFV = Min ( B .fwdarw. , D .fwdarw. ) - Max ( A .fwdarw. , C
.fwdarw. ) Expression 2 ##EQU00002##
Sixth Embodiment
[0086] Immediately after the clockwise oscillation of the nozzle, a
part of the high-pressure hydraulic fluid flows into the right flow
path of the receiver. When the right flow path is heavily inclined
from the vertical line, a part of the hydraulic fluid flowing into
the right flow path is reflected upward and collides with the right
half of the protruding surface of the nozzle. Immediately after the
nozzle is oscillated counterclockwise, a part of the high-pressure
hydraulic fluid flows into the left flow path of the receiver. When
the left flow path is heavily inclined from the vertical line, a
part of the hydraulic fluid flowing into the left flow path is
reflected upward and collides with the left half of the protruding
surface of the nozzle. Thus, a flow reflected from the right flow
path and the left flow path can cause an assisting force in the
oscillation of the nozzle. In a sixth embodiment, a technique of
improving the response using the reflected flow will be
described.
[0087] FIGS. 8A and 8B are schematic enlarged views of the
servo-valve 100 in the periphery of the protruding surface 223. The
explanation of the first embodiment is incorporated in the
description of the servo-valve 100. Referring to FIG. 8, the
servo-valve 100 will be described. In the embodiment, terms like
"upward," "downward," "leftward," "rightward," "clockwise,"
"counterclockwise," "vertical," and "horizontal" indicating
directions are used merely for the purpose of making the
explanation unambiguous. The principle of the embodiments is not by
any means limited by these terms denoting the directions.
[0088] The nozzle 200 shown in FIG. 8A is slightly oscillated
clockwise from the neutral position. At this time, most of the
hydraulic fluid discharged from the discharge port 221 flows into
the left flow path 313 extended from the left inflow port 311 to
the lower left side and a part of the hydraulic fluid flows into
the right flow path 314 extended from the right inflow port 312 to
the right lower side. When the nozzle 200 is oscillated clockwise
so that the inclination angle of the discharge line DCL from the
vertical line VL increases, the inclination angle or the discharge
line DCL from the vertical line VL approaches the inclination angle
of the left flow path 313 from the vertical line VL. All this
while, an angle between the discharge line DCL from the vertical
line VL and the center line of the right flow path 314 becomes
substantially a right angle. Thus, when the nozzle 200 is
oscillated clockwise from the neutral position, the hydraulic fluid
flowing into the left inflow port 311 smoothly flows along the left
flow path 313 and the hydraulic fluid which flows into the right
inflow port 312 is easily reflected by the wall surface of the
right flow path 314.
[0089] When the nozzle 200 is oscillated clockwise from the neutral
position, the right half of the circumferential surface 225 of the
protruding surface 223 which is positioned at a position right
above the right inflow port 312 has an inclination which is
parallel to the upper surface 310 of the receiver 300 (that is, the
right inflow port 312) when the nozzle 200 is positioned at the
neutral position. Thus, the right half of the circumferential
surface 225 of the protruding surface 223 easily collides with the
hydraulic fluid reflected by the wall surface of the right flow
path 314. The collision between the right half of the
circumferential surface 225 of the protruding surface 223 and the
hydraulic fluid reflected by the wall surface of the right flow
path 314 results in an assisting force of assisting the clockwise
oscillation of the nozzle 200. Thus, the nozzle 200 is highly
responsively oscillated clockwise.
[0090] The nozzle 200 shown in. FIG. 8B is slightly oscillated
counterclockwise from the neutral position. At this time, most of
the hydraulic fluid discharged from the discharge port 221 flows
into the right flow path 314 and a part of the hydraulic fluid
flows into the left flow path 313. When the nozzle 200 is
oscillated counterclockwise so that the inclination angle of the
discharge line DCL from the vertical line VL increases, the
inclination angle of the discharge line DCL from the vertical line
VL approaches the inclination angle of the right flow path 314 from
the vertical line VL. All this while, an angle between the
discharge line DCL from the vertical line VL and the center line of
the left flow path 313 approaches right angle. Thus, when the
nozzle 200 is oscillated counterclockwise from the neutral
position, the hydraulic fluid which flows into the right inflow
port 312 smoothly flows along the right, flow path 314 and the
hydraulic fluid which flows into the left inflow port 311 is easily
reflected by the wall surface of the left flow path 313.
[0091] When the nozzle 200 is oscillated counterclockwse from the
neutral position, the left half of the circumferential surface 225
of the protruding surface 223 positioned right above the left
inflow port 311 has an inclination parallel to the upper surface
310 of the receiver 300 (that is, the left, inflow port 311)
compared to a case where the nozzle 200 is positioned at the
neutral position. Thus, the left half of the circumferential
surface 225 of the protruding surface 223 easily collides with the
hydraulic fluid reflected by the wall surface of the left flow path
313. The collision between the left half of the circumferential
surface 225 of the protruding surface 223 and the hydraulic fluid
reflected by the wall surface of the left flow path 313 results in
an assisting force of assisting the counterclockwise oscillation of
the nozzle 200. Thus, the nozzle 200 is highly responsively
oscillated counterclockwise.
[0092] In the embodiment, a first flow path is exemplified by one
of the right flow path 314 and the left flow path 313. A second
flow path is exemplified by the other of the right flow path 314
and the left flow path 313. A first flow path wall is exemplified
by a flow path wall forming one of the right flow path 314 and the
left flow path 313. A second flow path wall is exemplified by a
flow path wall forming the other of the right flow path 314 and the
left flow path 313. A first fluid is exemplified by the hydraulic
fluid flowing into one of the right flow path 314 and the left flow
path 313. A second fluid is exemplified by the hydraulic fluid
flowing into the other of the right flow path 314 and the left flow
path 313.
Seventh Embodiment
[0093] The servo-valve according to the above-described embodiment
can be assembled to various fluidic devices driven by the hydraulic
fluid. In a seventh embodiment, an illustrative fluidic device will
be described.
[0094] FIG. 9 is a schematic diagram showing a fluidic device 500
of the seventh embodiment. Referring to FIGS. 1 and 9, the fluidic
device 500 will be described. The explanation of the first
embodiment is incorporated in the description of the elements
indicated by the same reference numerals as in the first
embodiment.
[0095] The fluidic device 500 includes a servo-valve 100D and an
actuator 600. Like the first embodiment, the servo-valve 100D
includes a receiver 300. The explanation of the first embodiment is
incorporated in the description of the receiver 300. The left flow
path 313 and the right flow path 314 formed in the receiver 300 may
be designed based on the design principle described in the sixth
embodiment.
[0096] The servo-valve 100D includes a torque motor 400D. The
torque motor 400D corresponds to the driving unit 400 described
with reference to FIG. 1. The explanation of the driving unit 400
is incorporated in the description of the torque motor 400D.
[0097] The torque motor 400D includes a lower coil 411, an upper
coil 412, a lower magnetic piece 421, an upper magnetic piece 422,
and a magnetic rod 430. The upper coil 412 is disposed above the
lower coil 411. The lower magnetic piece 421 may be formed in a
substantially cylindrical form. The lower coil 411 is accommodated
inside the lower magnetic piece 421. Like the lower magnetic piece
421, the upper magnetic piece 422 may be formed in a substantially
cylindrical form. The upper coil 412 is disposed inside the upper
magnetic piece 422. The lower edge of the upper magnetic piece 422
faces the upper edge of the lower magnetic piece 421. The magnetic
rod 430 extends substantially horizontally. The left and right ends
of the magnetic rod 430 are positioned inside a gap between the
upper edge of the lower magnetic piece 421 and the lower edge of
the upper magnetic piece 422.
[0098] A current is supplied to the lower coil 411 and the upper
coil 412. As a result, the lower magnetic piece 421 and the upper
magnetic piece 422 serve as magnets. When a current is supplied to
the lower coil 411 and the upper coil 412 so that the right end of
the magnetic rod 430 is pulled to the lower magnetic piece 421 and
the left end of the magnetic rod 430 is pulled to the upper
magnetic piece 422, the magnetic rod 430 rotates clockwise. When a
current is supplied to the lower coil 411 and the upper coil 412 so
that the left end of the magnetic rod 430 is pulled to the lower
magnetic piece 421 and the right end of the magnetic rod 430 is
pulled to the upper magnetic piece 422, the magnetic rod 430
rotates counterclockwise.
[0099] The servo-valve 100D includes a nozzle portion 200D. The
nozzle portion 200D corresponds to the nozzle 200 described with
reference to FIG. 1. The explanation of the nozzle 200 may be
incorporated in the description of the nozzle portion 200D.
[0100] The nozzle portion 200D includes a nozzle piece 240, a
flexible tube 250, and a coupling shaft 260. The flexible tube 250
extends vertically to penetrate the torque motor 400D. The nozzle
piece 240 is attached to the lower end of the flexible tube 250.
The high-pressure hydraulic fluid is supplied to the flexible tube
250. The hydraulic fluid is guided by the flexible tube 250 to
reach the nozzle piece 240.
[0101] The nozzle piece 240 includes a lower surface 241 which
faces the upper surface 310 of the receiver 300. The lower surface
241 is provided with a discharge port 242. The protruding form of
the lower surface 241 is determined based on the design principle
described in the above-described embodiments. The high-pressure
hydraulic fluid which is supplied to the nozzle piece 240 is
discharged from the discharge port 242. Subsequently, the hydraulic
fluid flows into the receiver 300.
[0102] The coupling shaft 260 is used so that the flexible tube 250
is coupled to an intermediate portion of the magnetic rod 430. The
flexible tube 250 and the nozzle piece 240 move left and right in a
reciprocating manner in response to the clockwise and
counterclockwise rotations of the magnetic rod 430. In the
embodiment, the first position is exemplified by the position of
the nozzle piece 240 moving left or right from the neutral position
(the position of the nozzle piece 240 in which the point of
intersection between the upper surface 310 of the receiver 300 and
the extended line extended from the center of the discharge port
242 in the hydraulic fluid discharge direction is located between
the left inflow port 311 and the right inflow port 312). The second
position is exemplified by the position of the nozzle piece 240
moving right or left from the neutral position.
[0103] When the magnetic rod 430 rotates about the coupling shaft
260 clockwise, the nozzle piece 240 moves leftward. As a result,
the area of overlapping between the discharge port 242 and the left
inflow port 311 increases and the area of overlapping between the
discharge port 242 and the right inflow port 312 decreases. In this
case, the amount of the hydraulic fluid flowing into the left flow
path 313 formed inside the receiver 300 exceeds the flow rate of
the hydraulic fluid flowing into the right flow path 314.
[0104] When the magnetic rod 430 rotates about the coupling shaft
260 counterclockwise, the nozzle piece 240 moves rightward. As a
result, the area of overlapping between the discharge port 242 and
the right inflow port 312 increases and the area of overlapping
between the discharge port 242 and the left inflow port 311
decreases. In this case, the amount of the hydraulic fluid flowing
into the right flow path 314 formed inside the receiver 300 exceeds
the flow rate of the hydraulic fluid flowing into the left flow
path 313.
[0105] The actuator 600 includes a casing 610 and a movable piece
620. The casing 610 is provided with two ports 611 and 612. The
port 611 of the actuator 600 is connected in fluid communication
with the left outflow port 315 of the receiver 300. That is, the
port 611 of the actuator 600 is connected to the left flow path 313
extended from the left inflow port 311 of the receiver 300. The
port 612 of the actuator 600 is connected in fluid communication
with the right outflow port 316 of the receiver 300. That is, the
port 612 of the actuator 600 is connected to the right flow path
314 extended from the right inflow port 312 of the receiver 300. In
the embodiment, a first outflow port is exemplified by one of the
port 611 and the port 612. A second outflow port is exemplified by
the other of the port 611 and the port 612.
[0106] The movable piece 620 includes a partition wall 621 and a
rod 622. The partition wall 621 divides the inner space of the
casing 610 into a left chamber 631 and a right chamber 632. The
port 611 is coupled to the left chamber 631. The left chamber 631
forms a terminal end portion of the flow path of the hydraulic
fluid which flows into the left flow path 313. The port 612 is
coupled to the right chamber 632. The right chamber 632 forms a
terminal end portion of the flow path of the hydraulic fluid
flowing into the right flow path 314. The rod 622 extends right
from the partition wall 621 and protrudes to the outside of the
casing 610. The rod 622 is connected to other external devices (not
shown) disposed outside the casing 610. In the embodiment, a hollow
portion is exemplified by the inner space of the casing 610.
[0107] When the nozzle piece 240 moves leftward, the hydraulic
fluid mainly flows from the discharge port 242 of the nozzle piece
240 to the left inflow port 311 of the receiver 300. Subsequently,
the hydraulic fluid which flows into the left inflow port 311 flows
into the left chamber 631 through the left flow path 313 of the
receiver 300, the left outflow port 315 of the receiver 300, and
the port 611 of the actuator 600. As a result, the inner pressure
of the left chamber 631 increases so that the movable piece 620
moves rightward. All this while, the hydraulic fluid existing
inside the right chamber 632 is blown out from the right inflow
port 312 through the port 612 of the actuator 600, the right
outflow port 316 of the receiver 300, and the right flow path 314
of the receiver 300. The hydraulic fluid blown out from the right
inflow port 312 collides with the protruding portion formed in the
lower surface 241 of the nozzle piece 240 and gives an assisting
force of assisting the left movement of the nozzle piece 240 to the
nozzle piece 240. Thus, the nozzle piece 240 can highly
responsively move left.
[0108] When the nozzle piece 240 moves rightward, the hydraulic
fluid mainly flows from the discharge port 242 of the nozzle piece
240 to the right inflow port 312 of the receiver 300. Subsequently,
the hydraulic fluid which flows into the right inflow port 312
flows into the right chamber 632 through the right flow path 314 of
the receiver 300, the right outflow port 316 of the receiver 300,
and the port 612 of the actuator 600. As a result, the inner
pressure of the right chamber 632 increases so that the movable
piece 620 moves leftward. All this while, the hydraulic fluid
existing inside the left chamber 631 is blown out from the left
inflow port 311 through the port 611 of the actuator 600, the left
outflow port 315 of the receiver 300, and the left flow path 313 of
the receiver 300. The hydraulic fluid blown out from the left
inflow port 311 collides with the protruding portion formed in the
lower surface 241 of the nozzle piece 240 and gives an assisting
force of assisting the right movement of the nozzle piece 240 to
the nozzle piece 240. Thus, the nozzle piece 240 can highly
responsively move right.
[0109] In FIG. 9, the receiver 300 is drawn separately from the
casing 610 of the actuator 600. However, the receiver 300 may be
integrated with the casing 610 of the actuator 600.
Eighth Embodiment
[0110] The actuator described in the seventh embodiment is directly
coupled to the receiver. Alternatively, the spool valve may be
disposed between the receiver and the actuator. In an eighth
embodiment, an illustrative fluidic device including the spool
valve will be described.
[0111] FIG. 10 is a schematic diagram showing a fluidic device 500E
of the eighth embodiment. Referring to FIG. 10, the fluidic device
500E will be described. The explanation of the seventh embodiment
is incorporated in the description of the elements denoted by the
same reference numerals as those of the seventh embodiment.
[0112] Like the seventh embodiment, the fluidic device 500E
includes the actuator 600. The explanation of the seventh
embodiment is incorporated in the description of the actuator
600.
[0113] The fluidic device 500 E further includes aservo-valve 100k,
two pumps 510 and 520, and a tank 530. Like the seventh embodiment,
a servo-valve 100E includes a nozzle portion 200E, the receiver
300, and a torque motor 400D. The explanation of the seventh
embodiment is incorporated in the description of these
elements.
[0114] The servo valve 100E further incudes a spoolvalve 700. The
spool valve 700 includes a casing 710, a spool 720, and a
cantilever spring 730. The spool 720 is disposed inside the casing
710. As a result, a flow path through which the hydraulic fluid
flows is formed inside the casing 710. The cantilever spring 730 is
used so that the casing 710 and the spool 720 are coupled to each
other. The cantilever spring 730 applies a force of keeping the
spool 720 at the closed position to the spool 720. When the spool
720 is located at the closed position, the spool valve 700
interrupts the hydraulic fluid supply path from the pumps 510 and
520 to the actuator 600. When the spool 720 moves leftward or
rightward from the closed position, the spool valve 700 opens the
hydraulic fluid supply path from the pumps 510 and 520 to the
actuator 600.
[0115] The casing 710 is provided with seven ports 711 to 717. The
port 711 is connected in fluid communication with the left outflow
port 315 of the receiver 300. The port 712 is connected in fluid
communication with the right outflow port 316 of the receiver 300.
The pumps 510 and 520 are respectively attached to the ports 713
and 714. The ports 715 and 716 are connected in fluid communication
with the actuator 600. The tank 530 is attached to the port
717.
[0116] The spool 720 includes four partition walls 721, 722, 723,
and 724 and a coupling shaft 725 used so that the partition walls
721, 722, 723, and 724 are coupled to one another. The coupling
shaft 725 extends substantially horizontally. The partition wall
721 is formed at the left end of the coupling shaft 725. The
partition wall 722 is formed at the right end of the coupling shaft
725. The partition wall 723 is located between the partition walls
721 and 722. The partition wall 724 is located between the
partition walls 722 and 723.
[0117] The partition walls 721, 722, 723, and 724 divide the inner
space of the casing 710 into five chambers 741, 742, 743, 744, and
745. The chamber 741 moves to the leftmost side. The chamber 742
moves to the rightmost side. The chamber 743 is formed between the
partition walls 721 and 723. The chamber 744 is formed between the
partition walls 722 and 724. The chamber 745 is formed between the
partition walls 723 and 724.
[0118] When the nozzle piece 240 moves leftward, the hydraulic
fluid mainly flows from the discharge port 242 of the nozzle piece
240 to the left inflow port 311 of the receiver 300. Subsequently,
the hydraulic fluid which flows into the left inflow port 311 flows
into the chamber 741 through the left flow path 313 of the receiver
300, the left outflow port 315 of the receiver 300, and the port
711 of the spool valve 700. As a result, the inner pressure of the
chamber 741 increases and the spool 720 moves rightward from the
closed position. All this while, the hydraulic fluid which exists
inside the chamber 742 is blown out from the right inflow port 312
through the port 712 of the spool valve 700, the right outflow port
316 of the receiver 300, and the right flow path 314 of the
receiver 300. The hydraulic fluid blown out from the right inflow
port 312 collides with the protruding portion formed in the lower
surface 241 of the nozzle piece 240 and gives an assisting force of
assisting the left movement of the nozzle piece 240 to the nozzle
piece 240. Thus, the nozzle niece 240 can highly responsively move
left.
[0119] Subsequently, when the nozzle piece 240 returns to the
neutral position, the hydraulic fluid ejected from the discharge
port 242 of the nozzle piece 240 flows in substantially in the same
quantity into the left inflow port 311 and the right inflow port
312 of the receiver 300. All this while, a force exerted on the
left side of the spool 720 is larger than a force exerted on the
right side of the spool 720 by a magnitude commensurate with the
resilience of the cantilever spring 730. Thus, the spool 720 moves
leftward and returns to the closed position.
[0120] When the nozzle piece 240 moves rightward, the hydraulic
fluid mainly flows from the discharge port 242 of the nozzle piece
240 to the right inflow port 312 of the receiver 300. Subsequently,
the hydraulic fluid which flows into the right inflow port 312
flows into the chamber 742 through the right flow path 314 of the
receiver 300, the right outflow port 316 of the receiver 300, and
the port 712 of the spool valve 700. As a result, the inner
pressure of the chamber 742 increases and the spool 720 moves
leftward from the closed position. All this while, the hydraulic
fluid which exists inside the chamber 741 is blown out from the
left inflow port 311 through the port 711 of the spool valve 700,
the left outflow port 315 of the receiver 300, and the left flow
path 313 of the receiver 300. The hydraulic fluid blown out from
the left inflow port 311 collides with the protruding portion
formed in the lower surface 241 of the nozzle piece 240 and gives
an assisting force of assisting the right movement of the nozzle
piece 240 to the nozzle piece 240. Thus, the nozzle piece 240 can
highly responsively move right.
[0121] Subsequently, when the nozzle piece 240 returns to the
neutral position, the hydraulic fluid which is ejected from the
discharge port 242 of the nozzle piece 240 flows in substantially
in the same quantity into the left inflow port 311 and the right
inflow port 312 of the receiver 300. All this while, a force
exerted on the right side of the spool 720 is larger than a force
exerted on the left side of the spool 720 by a magnitude
commensurate with the resilience of the cantilever spring 730.
Thus, the spool 720 moves rightward and returns to the closed
position.
[0122] In the embodiment, the first movable piece is exemplified by
the spool 720. The first outflow port is exemplified by one of the
ports 711 and 712. The second outflow port is exemplified by the
other of the ports 711 and 712.
[0123] When the spool 720 is located at the closed position, the
partition wall 723 closes the port 715. At this time, the partition
wall 724 closes the port 716. The pump 510 supplies the
high-pressure hydraulic fluid to the chamber 743 through the port
713. The pump 520 supplies the high-pressure hydraulic fluid to the
chamber 744 through the port 714. When the spool 720 moves
rightward from the closed position, the hydraulic fluid supply path
from the chamber 743 to the actuator 600 and the hydraulic fluid
discharge from the actuator 600 to the chamber 745 are opened. When
the spool 720 moves leftward from the closed position, the
hydraulic fluid supply path from the chamber 744 to the actuator
600 and the hydraulic fluid discharge path from the actuator 600 to
the chamber 745 are opened. Thus, the amount of the hydraulic fluid
flowing from the ports 715 and 716 to the actuator 600 is adjusted
by the left and right movement of the nozzle piece 240.
[0124] When the spool 720 moves rightward from the closed position,
the hydraulic fluid which is supplied from the pump 510 to the
chamber 743 through the port 713 flows into the left chamber 631
through the ports 715 and 611. Since the inner pressure of the left
chamber 631 increases, the movable piece 620 moves rightward. All
this while, the right chamber 632 communicates with the chamber 745
through the ports 612 and 716. The hydraulic fluid which exists
inside the right chamber 632 is extruded from the right chamber 632
by the movable piece 620 moving right so that the hydraulic fluid
flows to the chamber 745. Subsequently, the hydraulic fluid which
flows into the chamber 745 is stored in the tank 530.
[0125] When the spool 720 moves leftward from the closed position,
the hydraulic fluid which is supplied from the pump 520 to the
chamber 744 through the port 714 flows into the right chamber 632
through the ports 716 and 612. Since the inner pressure of the
right chamber 632 increases, the movable piece 620 moves leftward.
All this while, the left chamber 631 communicates with the chamber
745 through the ports 611 and 715. The hydraulic fluid which exists
inside the left chamber 631 is extruded from the left chamber 631
by the movable piece 620 moving left so that the hydraulic fluid
flows into the chamber 745. Subsequently, the hydraulic fluid which
flows into the chamber 745 is stored in the tank 530. In the
embodiment, the second movable piece is exemplified by the movable
piece 620.
[0126] In FIG. 10, the receiver 300 is drawn separately from the
casing 710 of the spool valve 700. However, the receiver 300 may be
integrated with the casing 710 of the spool valve 700.
[0127] In the embodiment, the cantilever spring 730 is coupled to
the spool 720 and the casing 710. Instead of the cantilever spring
730, an elastic member coupling the spool 720 and the nozzle
portion 2001 to each other may be used.
Ninth Embodiment
[0128] The inventors analyzed a relation between the form of the
lower surface of the nozzle and the force (the flow force) applied
from the hydraulic fluid to the nozzle by using two models in which
the lower surface of the nozzle has a different form. In a ninth
embodiment, an analysis result is will be described.
[0129] FIGS. 11A and 11B are graphs showing a relation among the
relative position of the nozzle with respect to the receiver, the
flow rate of the hydraulic fluid discharged from the nozzle, and
the force applied from the hydraulic fluid to the nozzle. The data
shown in FIG. 11A can be obtained from the nozzle which is designed
based on the design principle described in the first embodiment and
the lower surface of the nozzle is provided with a truncated
conical protrusion. The data shown in FIG. 11B can be obtained from
the known nozzle and lower surface of the nozzle is flat (that is,
no protrusion exist on the lower surface of the nozzle). Referring
to FIGS. 11A and 11B, an advantageous effect obtained from the
protrusion form of the lower surface of the nozzle will be
described.
[0130] The horizontal axes of the graphs of FIGS. 11A and 11B
respectively represent the relative position of the nozzle with
respect to the receiver. The original points of the graphs of FIGS.
11A and 11B represent the neutral positions. The vertical axes of
the graphs of FIGS. 11A and 11B represent the hydraulic fluid
discharge amount and the force applied from the hydraulic fluid to
the nozzle.
[0131] Regarding the nozzle movement direction and the flow force,
the "positive" direction of FIGS. 11A and 11B represents the "right
side." The "negative" direction of FIGS. 11A and 11B represents the
"left side."
[0132] The nozzle receives a pressure of the hydraulic fluid inside
the nozzle flow path or a force caused by the separation of the
hydraulic fluid in the vicinity of the outer circumferential
surface of the nozzle in addition to the force applied from the
hydraulic fluid blown out from the receiver. The pressure of the
hydraulic fluid inside the nozzle flow path or the force caused by
the separation of the hydraulic fluid in the vicinity of the outer
circumferential surface of the nozzle acts as a drag in a direction
opposite to the nozzle displacement direction.
[0133] The average value of the flow force shown in FIG. 11A is
remarkably smaller than the average value of the flow force shown
FIG. 11B. This means that the collision between the protrusion
formed in the lower surface of the nozzle and the hydraulic fluid
blown out from the receiver cancels the above-described drag. Since
the drag for the movement of the nozzle including the lower surface
provided with the protrusion is reduced throughout the stroke of
the nozzle, the nozzle including the lower surface provided with
the protrusion can highly responsively move left and right.
Meanwhile, since the drag for the movement of the nozzle including
the flat lower surface is not substantially reduced, the nozzle
including the flat lower surface is worse in response than the
nozzle including the lower surface provided with the
protrusion.
[0134] The variation width of the flow force shown in FIG. 11A is
remarkably smaller than the variation width of the flow force shown
in FIG. 11B. This means that the position control of the nozzle is
hardly influenced by the stroke position of the nozzle or the flow
rate of the hydraulic fluid when the lower surface of the nozzle is
provided with the protrusion. Thus, the nozzle described in the
above-described embodiments is better than the known nozzle from
the viewpoint of the response and the position control
accuracy.
[0135] The embodiments of the invention have been described above.
In the servo-valve according to the embodiment, the nozzle is
provided with the force generation portion which causes an
assisting force colliding with the fluid blown out from the inflow
port and acting in a direction matching the displacement direction.
Accordingly, since the nozzle easily receives the assisting force
acting in the displacement direction, the response speed of the
actuator is improved.
[0136] Here, in the cross-section passing through the discharge
line DCL of the nozzle 200 shown in FIG. 12, an angle which is
formed by the circumferential surface 225 and the discharge line
DCL is set to a peripheral angle .alpha.. The peripheral angle
.alpha. is set in response to, for example, the flow rate of the
fluid. For example, the peripheral angle .alpha. is set to be large
when the flow rate of the fluid is small and the peripheral angle
.alpha. is set to be small when the flow rate is large in order to
allow the nozzle 200 to move by an appropriate assisting force. The
peripheral angle .alpha. is desirably 0 to 60.degree., more
desirably 3 to 50.degree., further desirably 5 to 40.degree., and
particularly desirably 8 to 30.degree.. A vibration model is
considered in which the nozzle 200 is connected to the spool 720
and the fluid in the servo-valve 100. In this model, when the flow
force increases so that an equivalent spring constant caused by the
fluid increases, the operation becomes unstable due to the
vibration of the nozzle 200. Here, an angle in which the flow force
increases so that the operation of the nozzle 200 becomes unstable
is set to the upper limit of the peripheral angle .alpha.. Further,
an angle in which the flow force for the servo-valve 100 becomes
zero is set to the lower limit of the peripheral angle .alpha..
[0137] FIG. 13 is a partially enlarged view of a nozzle 200F
according to a modified example. The nozzle 200F shown in FIG. 13
is provided with a recess 226 which is continuous from the end
surface 224 to the discharge port 221. The recess 226 extends
upward along the discharge line DCL from the end surface 224 and is
formed in a truncated cone form of which a diameter decreases
upward. Like the circumferential surface 225, the inner peripheral
surface of the recess 226 receives an assisting force acting in the
displacement direction of the nozzle 200F. Accordingly, the
assisting force exerted on the nozzle 200F increases. In addition,
the form of the recess 226 is not limited thereto and may be
different from the illustrative form.
[0138] The design principle described in the above-described
various embodiments can be applied to various servo-valves and
various fluidic devices. A part of various features described in
one of the above-described various embodiments may be applied to
the servo-valve and the fluidic device described in other
embodiments.
[0139] An aspect of the invention is as follows. A servo-valve
according to an aspect controls a fluid discharged from a discharge
port of a nozzle by displacing the nozzle and drives an actuator.
The servo-valve includes a receiver that includes an inflow surface
provided with a first inflow port and a second inflow port into
which the fluid discharged from the discharge port flows. The
nozzle includes a force generation portion that includes an end
surface provided with the discharge port and an outer
circumferential surface formed in the periphery of the end surface.
When the nozzle is displaced from a neutral position in which an
extended line extended from a center of the discharge port
intersects the inflow surface between the first inflow port and the
second inflow port toward a position in which the extended line
intersects the first inflow port, the fluid inside the second
inflow port is blown out toward the nozzle. The force generation
portion collides with the fluid blown out from the second inflow
port and causes an assisting force in a direction matching the
nozzle displacement direction.
[0140] According to the above-described configuration, since the
force generation portion collides with the fluid blown out from the
second inflow port and causes an assisting force in a direction
matching the nozzle displacement direction toward the first inflow
port, the displacement of the nozzle toward the first inflow port
is assisted by the assisting force. Since the nozzle can be quickly
displaced toward the first inflow port under the action of the
assisting force, the servo-valve can quickly drive the
actuator.
[0141] In the above-described confirmation, when the nozzle is
displaced from the neutral position toward a position in which the
extended line intersects the second inflow port, the fluid inside
the first inflow port may be blown out toward the nozzle. The force
generation portion may collide with the fluid blown out from the
first inflow port and cause an assisting force in a direction
matching the nozzle displacement direction toward the second inflow
port.
[0142] According to the above-described configuration, since the
force generation portion collides with the fluid blown out from the
first inflow port and causes an assisting force in a direction
matching the nozzle displacement direction toward the second inflow
port, the displacement of the nozzle toward the second inflow port
is assisted by the assisting force. Since the nozzle can be quickly
displaced toward the second inflow port under the action of the
assisting force, the servo-valve can quickly drive the
actuator.
[0143] In the above-described confirmation, the force generation
portion may be a cone which protrudes toward the inflow surface and
grows narrower toward the inflow surface. The outer circumferential
surface may include a first force generation surface that causes an
assisting force for the displacement of the nozzle toward the first
inflow port and a second force generation surface that causes an
assisting force for the displacement of the nozzle toward the
second inflow port.
[0144] According to the above-described configuration, since the
outer circumferential surface of the cone includes the first force
generation surface and the second force generation surface, the
nozzle can have a simple structure for obtaining a first assisting
force and a second assisting force.
[0145] In the above-described confirmation, the first force
generation surface may face the second inflow port. The second
force generation surface may face the first inflow port.
[0146] According to the above-described configuration, since the
first force generation surface faces the second inflow port, the
first force generation surface can strongly cause a first assisting
force immediately after the nozzle is displaced from the neutral
positron toward the first inflow port. Since the second force
generation surface faces the first inflow port, the second force
generation surface can strongly cause a second assisting force
immediately after the nozzle is displaced from the neutral position
toward the second inflow port.
[0147] In the above-described confirmation, the nozzle may include
a facing surface that faces the inflow surface. The facing surface
may be formed within the first virtual plane. The cone may include
a discharge end surface that is formed within a second virtual
plane defined between the first virtual plane and the inflow
surface and is provided with the discharge port. A first outline of
the cone within the first virtual plane may be surrounded by an
outer edge of the facing surface. A second outline of the cone
within the second virtual plane may surround the discharge
port.
[0148] According to the above-described configuration, since the
first outline is surrounded by the outer edge of the facing surface
and the second outline surrounds the discharge port, the outer
circumferential surface is positioned between the outer edge of the
facing surface and the discharge port. Thus, the force generation
portion can collide with the fluid blown out from the first inflow
port or the second inflow port and cause the first assisting force
or the second assisting force.
[0149] In the above-described confirmation, the first outline may
form a concave corner between the outer circumferential surface and
the facing surface.
[0150] According to the above-described configuration, since the
cone protrudes from the concave corner, the fluid blown out from
the first inflow port or the second inflow port can flow toward the
outer edge of the facing surface while not substantially staying at
a certain position.
[0151] In the above-described confirmation, the nozzle may include
a facing surface that faces the inflow surface. The facing surface
may be formed within the first virtual plane. The first force
generation surface and the second force generation surface may form
a groove portion that is recessed from the first virtual plane.
[0152] According to the above-described configuration, since the
first force generation surface and the second force generation
surface form the groove portion that is recessed from the first
virtual plane, the force generation portion may not protrude from
the facing surface. Thus, the nozzle may have a short axial
dimension.
[0153] In the above-described confirmation, the outer edge may be
formed at a position separated from each of the first inflow port
and the second inflow port in relation to a distance between the
first inflow port and the second force generation surface and a
distance between the second inflow port and the first force
generation surface.
[0154] According to the above-described configuration, since the
outer edge is formed at a position separated from each of the first
inflow port and the second inflow port in relation to a distance
between the first inflow port and the second force generation
surface and a distance between the second inflow port and the first
force generation surface, the flow of the fluid is stabilized
between the facing surface and the inflow surface. As a result, a
force generated from the flow of the fluid in the periphery of the
outer edge of the facing surface hardly acts in a direction
opposite to the nozzle displacement direction. Thus, the
servo-valve can quickly drive the actuator.
[0155] In the above-described confirmation, the receiver may
include a first flow path wall that forms a first flow path
extended from the first inflow port and a second flow path wall
that forms a second flow path extended from the second inflow port.
The inflow surface may divide the fluid discharged from the
discharge port into a first fluid flowing into the first inflow
port and a second fluid flowing into the second inflow port. When
the nozzle is displaced from the neutral position toward the first
inflow port, the second fluid may be reflected by the second flow
path wall toward the first force generation surface.
[0156] According to the above-described configuration, since the
second fluid is reflected toward the first force generation surface
by the second flow path wall when the nozzle is displaced from the
neutral position toward the first inflow port, the displacement of
the nozzle toward the first inflow port is assisted by the fluid
reflected toward the second surface by the second flow path wall.
Thus, the servo-valve can quickly drive the actuator.
[0157] In the above-described confirmation, when the nozzle is
displaced from the neutral position toward the second inflow port,
the first fluid may be reflected by the first flow path wall toward
the second force generation surface.
[0158] According to the above-described configuration, since the
first fluid is reflected by the first flow path wall toward the
second force generation surface when the nozzle is displaced from
the neutral position toward the second inflow port, the
displacement of the nozzle toward the second inflow port is
assisted by the fluid reflected by the first flow path wall toward
the first surface. Thus, the servo-valve can quickly drive the
actuator.
[0159] In the above-described confirmation, the servo-valve may
further include a driving unit displacing the nozzle and a casing
provided with a flow path through which the fluid flows. The casing
may be provided with a first outflow port connected to the first
inflow port and a second outflow port connected to the second
inflow port. The driving unit may displace the nozzle between the
first inflow port and the second inflow port to adjust the amount
of the fluid flowing out of the first outflow port and the amount
of the fluid flowing out of the second outflow port.
[0160] According to the above-described configuration, since the
driving unit displaces the nozzle between the first inflow port and
the second inflow port to adjust the amount of the fluid flowing
out of the first outflow port and the amount of the fluid flowing
out of the second outflow port, the designer can appropriately
select an assisting force action direction with respect to the
nozzle by changing the outflow amounts from the first outflow port
and the second outflow port.
[0161] In the above-described confirmation, the servo-valve may
further include a first movable piece that moves in a reciprocating
manner inside the casing by the fluid in response to the
displacement of the nozzle. When the nozzle is displaced toward the
first inflow port, the first movable piece may be displaced by the
fluid discharged to the first inflow port and extrude the fluid
from the second outflow port to blow out the fluid from the second
inflow port. When the nozzle is displaced toward the second inflow
port, the first movable piece may be displaced by the fluid
discharged to the second inflow port and extrude the fluid from the
first outflow port to blow out the fluid from the first inflow
port.
[0162] According to the above-described configuration, since the
first movable piece is displaced by the fluid discharged from the
first inflow port and blows out the fluid from the second inflow
port, the displacement of the nozzle toward the first inflow port
is assisted by the fluid blown out from the second inflow port.
When the nozzle is displaced toward the second inflow port, the
first movable piece is displaced by the fluid discharged to the
second inflow port and blows out the fluid from the first inflow
port, the displacement of the nozzle toward the second inflow port
is assisted by the fluid blown out from the first inflow port.
[0163] A fluidic device according to another aspect of the
invention includes the above-described servo-valve and an actuator
that includes a second movable piece operated in response to the
displacement of the first movable piece.
[0164] According to the above-described configuration, since the
fluidic device includes the above-described servo-valve, the nozzle
is highly responsively operated. As a result, the first movable
piece can be also highly responsively displaced. Since the second
movable piece of the actuator is operated in response to the
displacement of the first movable piece, the second movable piece
can be also highly responsively operated.
[0165] A fluidic device according to still another aspect of the
invention includes the above-described servo-valve and an actuator
that includes the casing and a movable piece dividing a hollow
portion formed by the casing to form the flow path. When the nozzle
is displaced toward the first inflow port, the movable piece is
displaced by the fluid discharged to the first inflow port and
extrudes the fluid from the second outflow port to blow out the
fluid from the second inflow port. When the nozzle is displaced
toward the second inflow port, the movable piece is displaced by
the fluid discharged to the second inflow port and extrudes the
fluid from the first outflow port to blow out the fluid from the
first inflow port.
[0166] According to the above-described configuration, since the
movable piece is displaced by the fluid discharged to the first
inflow port and blows out the fluid from the second inflow port
when the nozzle is displaced toward the first inflow port, the
displacement of the nozzle toward the first inflow port is assisted
by the fluid blown out from the second inflow port. Since the
movable piece is displaced by the fluid discharged to the second
inflow port and blows out the fluid from the first inflow port when
the nozzle is displaced toward the second inflow port, the
displacement of the nozzle toward the second inflow port is
assisted by the fluid blown out from the first inflow port.
[0167] The principle of the above-described embodiments is suitably
used for various devices for obtaining a driving force from a
fluid.
* * * * *