Note: Descriptions are shown in the official language in which they were submitted.
1319~8
The present invention concerns an automatic ~alve for
controlling the flow of fluid and, more specifically, it
relates to an automatic valve for controlling the flow of
fluid which valve is adapted to conduct ON-OFF operations
utilizing the magnetic attraction force between permanent
magnets.
Aspects of the prior art and preferred embodiments of
the invention will be illustrated by reference to the
accompanying drawings, in which:
FIG. 1 is a longitudinal cross-sectional view showing
one embodiment of an automatic valve according to the present
invention;
FIG. 2 is an enlarged cross ~ectional view illustrating
the arrangement of ring magnets that constitute a first
cylindrical multi-layered magnet of a smaller diameter and a
~econd cylindrical multi-layered magnet of a larger diameter,
respectlvely;
FIG. 3 is a cross sectional view of a valve shaft;
FIG. 4 is a transverse cross-sectional view showing the
shape o~ a discharge hole formed through the cylinder;
FIG. 5 is a longitudinal cross sectional view showing
another embodiment of an automatic valve according to the
present lnvention;
FIG. 6 i~ a longitudinal croes sectional view showing a
conventional automatic valve.
-- 1 --
, ~,
~319~8
Automatic valves of the afore-mentioned type have been
disclosed, for example, in Japanese Utility Model Application
Laid-Open Sho 60-8582. Referring to the descriptions in the
specification and the drawings (the outline of which is
iliustrated in FIG. 6 of the drawings, appended hereto only
for the reference), a valve shaft 4 that has a valve body 2
formed at the top end thereof for closing a fluid port lA and
a multi-layered cylindrical magnet MS of a small diameter
comprising a plurality of ring magnets 3, 3,-stacked axially
on the shaft and mounted on the rear end thereof, are housed
within a valve chamber 5 so as to be axially slidable
relative to the valve chamber.
At the outside of the valve chamber 5, a multi-layered
cylindrical magnet M~ of a large diameter comprising a
plurality of axially stacked ring magnets 6, 6-is disposed
coaxially with the cylindrical magnet MS and slidably along
the axial direction of the valve shaft 4. In the stack of
the magnets MS and ML, the magnetic polarity (N or S) is made
dif~erent between each of ring magnet pair 3 and 6 radially
opposQd to eaah other. A piston 7 having the cylindrical
magnet ML is disposed within a cylinder 8 and adapted to
~lide in a direction for opening or closing the valve by a
pressurized air or gas. The cylinder 8 has ports 9A and 98
for the pressurized air or gas, formed at both of the top and
rear ends thereof on both 6ides of the piston 7, so that the
pi~ton 7 is driven by the pressure of the pressurized air or
gas supplied alternately from the ports 9A and 9B.
When the piston 7 is caused to slide in the direction of
opening or closing the valve 7, the valve shaft 4 mounted
with the ~ulti-layered cylindrical magnet MS is caused to
~lide forwardly and backwardly by the magnetic attraction
- 2 -
, .. .
1319~68
force of the cylindrical multi-layered magnet ML, as a part
of the piston 7, to actuate the valve body 2, thereby opening
or closing the fluid port lA.
Since the valve shaft 4 housed within the valve chamber
5 is adapted to move~slidingly without protruding to the
outside through the side wall of the valve chamber 5, thereby
actuating the valve body 2 attached at the top end of the
shaft 4, a tight sealing can be obtained in the valve chamber
5 formed between the two ports lA and lB.
However, in a case where the automatic valve of such a
structure is used, for example, as a color-change valve in a
multi-color coating apparatus, there are variou~ problems.
Firstly, the valve body 2 when put in a closed state,
may possibly be separated ~rom the valve seat lO under the
e~fect of back pressure of paint acting ~rom the side of the
port lA.
Specifically, the valve o~ FIG. 6, when used as a paint
color-change valve i8 connected, ~or example, at the port lB,
to a paint supply source o~ a certain color and connected to
the other port lA, by way of a paint hose, to a mani~old
connected to a coating machine. However, since other color-
change valves for supplying paints of other dlfferent colors
are also connected with the mani~old, i~ the magnetic
attraction ~orce between the cylindrical magnets NS and ML
~or closing the color-change valve i8 not strong enough, the
valve body 2 for closing the port lA may possibly be
separated ~rom the valve seat 10 under the e~fect of the
pressure o~ a paint o~ di~erent color supplied from other
color-change valve to the inside o~ the mani~old. This may
- 3 -
,.. .
1319~68
bring about a risk of defective coatings due to the intrusion
of the paint of different color into the valve chamber 5 and
result in mixing of these paints.
Secondly, in the conventional automatic valve shown in
FIG. 6, since the piston 7 is adpated to be driven by
alternately supplying pressurized air or gas (simply referred
to as air, hereinafter) from the ports 9A and 9B formed on
both of the top and rear ends of the cylinder 8, air hoses
have to be connected to both of the ports 9A and 9B.
When the conventional automatic valve is used as a
color-change valve in a multi-color coating apparatus for
conducting coating under color-change, e.g., for more than
thirty kinds of colors, since a great number of air hoses
have to be disposed in addition to a number of paint hoses,
the number of pipeways, as well as switching valves for
selectively supplying pressurzed air to be respective air
hoses i8 also increased, so as to necessitate the expenditure
oP a huge installation cost and require a larger installation
space.
Furthermore, when the pi6ton 7 is driven by the
pre~urlzed air supplied from one of the port~ 9A or 9B,
~ince the alr pressurized by the piston 7 in the cylinder 8
has to be discharged Prom the other of the ports 9B or 9A,
the ON-OFF control Por the switching valve disposed to each
oP the air hoses becomes extremely complicated.
In order to overcome such a problem, the present
inventors have attempted to put the piston 7 under the
resilienay oP a spring that normally closes the valve and
drive the piston in the valve opening direction by the
- 4 -
,~
.. . .....
~ 319~6~
pressurized air supplied from the opposite direction and, at
the same time, release the air pressurized in the cylinder 8
upon driving the piston 7 directly to the outside through a
discharge hole perforated to the circumference of the
cylinder 8.
However, in the automatic valve used for the color-
change valve, since a solvent such as a thinner is blown to
the surface thereof for cleaning and removing a paint which
is sprayed fr.om the coating machine and deposited thereon,
the solvent may possibly intrude through the hole perforated
in the circumference of the cylinder 8 to the inside thereof,
thereby deteriorating the sealing members such as rubber
packings, etc. disposed on the inside of the cylinder.
Thirdly, when the automatic valve illustrated in FIG. 6
is used as a paint supply valve for controlling the flow of
paint supplied to a coating machine, the paint remaining in
the valve chamber 5 can not completely be removed upon
cleaning of paint pipeways in which the valve is disposed.
Specifically, if a cleaning solvent is supplied, for
example, from the port lB into the valve chamber 5 and
dischaxged from another port lA, it is impossible to
completely remove the paint that ha~ intruded into narrow
gaps ~ormed between the inner circumferential surface of the
cylindrical magnet MS that ~lides integrally with the valve
shaft 4 or the paint that has further invaded as far as the
rear end of the valve shaft 4 passing through cuch gaps.
This may possibly allow the paint to remain in the valve
chamber 5 in sliding contact with the circumferential surface
of the cylindriaal magnet MS.
1 3 ~ 8
Furthermore, if the paint intruding between the
circumferential surface of the cylindrical magnet MS and the
inner wall of the valve chamber 5 in sliding contact with
each other remains and solidifies there, it is no more
possible to move the cylindrical magnet MS with the magnetic
force of the cylindrical magnet ML, thereby hindering the
valve ON-OFF operation.
The present invention provides an automatic valve of the
aforementioned structure, but one capable of maintaining a
valve body in a completely closed state even when a backward
fluid (e.g. from paint) pressure is exerted, by increasing
the magnetic attraction force created between two cylindrical
magnets without enlarging the size of them.
The present invention also provides an automatic valve
of the aforementioned structure, but which is capable of
decreasing the number of air hose pipeways, by perforating a
discharge hole to a cylinder, while effectively preventing
the intrusion of solvent to the inside of the cylinder
through such a discharge hole.
ao Further, the present invention provides an automatic
valve o~ the aforementioned structure, but which is capable
of surely preventing color paints from remaining in the valve
¢hamber upon cleaning the inside of the chamber, and
preventing remained paints from solidification after the
cleaning which would otherwiqe hinder the ~liding movement of
the cylindri¢al magnet MS in the valve chamber.
More particularly, the present invention provides an
automatic valve comprising:
- 6 -
1 3 ~ 8
a valve chamber having at least two fluid ports;
a valve shaft contained in the valve chamber slidably in
the axial direction thereof, the valve shaft having a valve
body formed at the top end thereof for closing one of the
fluid ports and a first cylindrical multi-layered magnet of a
smaller diameter attached at the rear end thereof and
comprising a plurality of axially stacked ring magnets;
a cylinder disposed to the outer side of and coaxially
with the valve chamber;
a piston disposed axially slidably within the cylinder
and adapted to move in the direction of opening the valve by
the pressure of a pressurized gas or air;
a second cylindrical multi-layered magnet of a large
diameter comprising a plurality of axially stacked ring
magnets, which is constituted as a part of the cylinder and
arranged coaxially with the first cylindrical magnet such
that the respectlve ring magnets in the first cylindrical
magnet and the re~pective ring magnets in the second
¢ylindrlcal magnet are radially opposed to each other with
di~erent magnetl¢ polarity; in which
the respective ring magnets are stacked in each o~ the
~irst and second cylindrical magnets such that identical
magnetic poles are faced to each other in each àxially
ad~acent pair o~ ring magnets, and
the respective ring magnets in the second cylindrical
magnet are so situated that they are axially displaced
... ,~ :
1319~8
slightly toward the direction of closing the valve relative
to the respective radially opposed ring magnets in the first
cylindrical magnet with different magnetic polarity.
~he present invention also provides the automatic valve
of the just mentioned constitution, in which
a spring is disposed to the piston for resiliently
energizing the piston toward the direction of closing the
valve, the cylinder has a port formed at a position
corresponding to one side of the piston for receiving a
pressurized air or other gas that causes the piston to move
slidingly against the resiliency of the spring in the
direction of opening the valve and
a discharge hole formed at a position corresponding to
the other side of the piston, and the discharge hole
comprises a discharge channel opened to the inside of the
cylinder, a discharge channel opened to the outside of the
cylinder and a round-about bent channel for communicating
both o~ the channels with each other.
Further, the present invention provides the automatic
valve o~ the ~u~t mentioned constitution in which
an outer dlameter of the first cylindrical multi-layered
magnet attached to the rear end of the valve shaft is made
smaller than the inner diameter of the valve chamber, so as
to define a fluid channel between the outer circumferential
~urface of the first cylindrical magnet and of the valve
shaft and the inner wall ~urface of the valve chamber, and
, ;., .
` 1319~8
fluid ports are formed on both axial ends of the channel
opposing to both of the top and the rear ends of the valve
shaft respectively.
In the automatic valve according to the present
invention, since each of the first cylindrical magnet
attached on the rear end of a valve shaft housed axially
slidably within the valve chamber and the second cylindrical
magnet disposed on the outside of the valve chamber axially
slidably is arranged, so that respecti~e ring magnets are so
stacked that identical magnetic poles face each other in each
axially adjacent pair of ring maqnets, magnetic fluxes from
each of the cylindrical magnets are extremely increased and,
accordingly, the magnetic attraction force exerted between
both o~ them becomes greater.
As is well-known, when different poles of two opposing
magnets i.e., N and S poles are bought in contact with each
other, the magnetic poles at their opposed surfaces are
eliminated. I~ instead they are brought close to each other
although not into direct contact, magnetic ~luxes emitting,
~or example, ~rom the N pole o~ one o~ the magnets are
concentrated toward the S pole o~ the other o~ the magnets.
In ~uch a case, the magnetic attraction ~orce exerted, for
example, between the N-pole o~ the a~orementioned one magnet
and the S-pole o~ the third magnet opposed thereto is
extremely weakened.
On the other hand, i~ adjacent magnets are opposed to
each other at their identical polarity as seen in the
cylindrical magnets in the present invention, since a great
guantity o~ magnet ~luxes are emitted, ~or example, ~rom the
two N poles opposing each other in each pair o~ adjacent
131~8
magnets, and such magnetic fluxes are concentrated toward the
S poles of the magnet pair in the other cylindrical magnet
opposed thereto, the magnetic attraction force exerted
between the two cylindrical magnets becomes extremely
strengthened.
In addition, since the respective ring magnets in the
second cylindrical magnet are so situated that they are
slightly displaced axially toward the direction of closing
the valve relative to the respective radially opposed ring
magnets in the first cylindrical magnet with different
polarity in the closed state of the valve, and the valve
shaft attached to the first cylindrical magnet is energized
in the direction of closing the valve by the magnetic
attraction force exerted between them under this state, the
valve body formed at the top end of the valve shaft can be
maintained at a completely closed state against the backward
pressure of the fluid exerted thereon.
In another embodiment of the present invention, since
the spring is disposed to the piston for resiliently
energizing the piston toward the direction of closing the
valve, the cylinder has a port ~ormed at a position
corresponding to one side o~ the piston ~or receiving a
pressurized gas or air that aauses the piston to move
slidingly against the resiliency of the spring in the
direction o~ opening the valve when a pressurized gas or air
is supplied from the gas port in the closed state of the
valve, the piston including the second cylindrical magnet is
caused to slide in the direction of opening the valve against
the resiliency o~ the spring and, by the magnetic attraction
therewith, the valve sha~t attached with the ~irst
cylindrical magnet is also caused to slide in the direction
-- 10 --
1319~8
of opening the valve, to thereby open the fluid port which
has been closed so far with the valve body formed at the top
end of the valve shaft.
In this instance, gas or air present in the cylinder is
S discharged out of the cylinder through the discharge hole
formed on the opposite side.
Then, when the supply of the pressurized gas or air is
interrupted, the piston which has been caused to slide in the
direction of opening the valve is now caused to slide in the
direction of closing the valve by the resiliency of the
spring and, along therewith, the valve shaft is also caused
to slide in the direction of closing the valve, thereby
closing the fluid port again by the valve body formed at the
top end of the valve shaft.
With such an embodiment, since only one port is
necessary for the pressurized gas or air that drives the
piston, the number of air hose pipeways Sor supplying the
pres~urized gas or air can be decreased.
Moreover, since the cylinder has a discharge hole formed
at a pl~ton corresponding to the other side o~ the piston,
and the dis¢harge hole comprise~ a discharge channel which i5
open to the outside o~ the cylinder and a roundabout bent
channel ~or communicating both of the channels with each
other, if the cleaning solvent blown onto the surface of the
automatic valve should enter into the discharge channel which
is open to the outside o~ the cylinder, it can not reach the
discharge channel which i~ open to the inside of the cylinder
beyond the discharge channel, being hindered by the round-
about bent channel.
- 11 -
,~, i i,
~ ", ~
131~8
Accordingly, when paint deposited to the surface of the
automatic valve used as a color-change valve in a multi-color
coating apparatus is cleaned by a solvent such as a thinner,
it is possible to prevent intrusion of the solvent into the
inside of the cylinder, which would otherwise deteriorate the
packings, etc. made of rubber.
In a further construction according to of the present
invention, since a fluid channel is defined between the outer
circumferential surface of the first cylindrical magnet and
of the valve shaft and the inner wall surface of the valve
chamber, and fluid ports are formed on both axial ends of the
channel opposing both of the top and rear ends of the valve
shaft respectively, when the piston including the second
cylindrical magnet is caused to slide in the direction of
opening the valve and, along therewith, the valve shaft
having the valve body formed at the top end thereof and the
~irst cylindrical magnet formed at the rear end thereof is
moved in the direction of opening the valve, entering paint
supplied, ~or example, from the ~luid port opposed to the
rear end o~ the valve shaft, i5 passed through the channel
~ormed betwèen the outer circum~erential surface of the first
cyllndrical magnet and the valve sha~t and the inner
circum~erential wall o~ the valve chamber, discharged out o~
the ~luid port opposed to the top end o~ the valve sha~t and
then ~upplied to the coating machine.
Then, in the case of interrupting the supply of the
paint to the coating machine and cleaning the inside of the
valve chamber, a solvent such as a thinner supplied instead
of the paint is caused to flow from the port opposed to the
rear end of the valve ~ha~t to the inside of the valve
chamber, passed through the channel and then discharged from
- 12 -
i;, . . .
i3i~668
the port opposed to the top end of the valve shaft, whereby
the surface of the valve shaft and the first cylindrical
magnet attached to the rear end of the shaft, as well as the
inner wall of the valve chamber can be cleaned completely and
the paint remaining in the valve chamber can be removed
completely.
Accordingly, this can prevent the paint from remaining
in the valve chamber or and prevent the solidification of
pàint between the outer circumferential surface of the first
cylindrical magnet and the inner wall of the valve chamber,
which would otherwise hinder the sliding movement of the
cylindrical magnet.
~ he present invention is to be explained specifically by
way of its preferred embodiments referring to the
accompanying drawings.
FIG. l is a longitudinal cross seational view showing
one embodiment of an automatic valve according to the present
invention. FIG. 2 i~ an enlarged cross-sectional view
illu~trating the arrangement of magnet rings that constitute
a ~ir~t cylindrical multi-layered magnet o~ a ~maller
diameter and a ~econd cylindrical multi-layered magnet o~ a
larger diameter, respectively. FIG. 3 i~ a cross ~ectional
vlew o~ a valve ~haft. FIG. 4 is a transverse cross-
sectional view showing the shape o~ a di~charge hole ~ormed
through the cylinder.
In FIG. 1. through FIG. 4, components or members
corresponding to those shown ln FIG. 6 carry the same
re~erence numerals and detailed explanations o~ these
component~ or members are omitted.
- 13 -
131~8
In the embodiment shown in FIGS. 1 and 2, respective
ring magnets 3, 3,-constituting a first cylindrical multi-
layered magnet ~s of a smaller diameter and respective ring
magnets 6, 6,-constituting a second cylindrical multi-layered
magnet ML of a larger diameter are stacked such that
identical magnetic poles are faced to each other in each pair
of axially adjacent ring magnets 3, 3 or 6, 6 as shown in
FIG. 2. Further, respective ring magnets 6, 6,-of the first
cylindrical magnet ML are so situated that they are slightly
displaced axially in the direction of closing the valve
relative to the respective radially opposed magnet rings
3, 3,-of the first cylindrical magnet ML with different
magnetic polarity.
Each of the ring magnets 3, 3-is interposed between each
pair of ring-like yokes 11, 11 of the same diameter, fitted
over the outer circumference of a bolt 12 mounted on the rear
end of the valve shaft 4 and clamped thereto by means of a
nut 13 engaged to the bolt 12 against the repulsive force
exerted between ad;acent N poles and between adjacent S poles
in each other o~ the ad~acent magnet pair 3, 3,-.
In a ~imilar manner, each of the ring magnets 6, 6,-is
interpoeed between a pair of ring-like yokes 14 and 14 of the
same diameter, ~itted in the cylindrical pieton 7, and
clamped in an integrally ~tacked state against the repulsive
~orce exerted between the opposed identical magnetic poles in
each o~ the axially adjacent magnets 6, 6-by means of a C-
~haped stopper ring 15 fitted into a radially inwardly-
opening circumferential groove shown provided in the inner
wall of the piston 7.
The first cylindrical magnet MS attached to the rear end
- 14 -
13196~8
of the valve shaft 4 has an outer diameter smaller than the
inner diameter of a valve chamber 5 that is defined within a
hollow body 16 having a valve ~eat 10 defining therein a flow
port lA at one end thereof and a cylindrical tube 18 made of
aluminum and attached to the other end thereof, so that a
channel 19 is formed between the outer circumferential
surface of the valve shaft 4 and the first cylindrical magnet
MS and the inner wall surface of the valve chamber 5 for
allowing a fluid to pass therethrough.
As shown in FIG. 3, the valve shaft 4 is manufactured by
chamferring the four corners of a square metal. Thus, the
valve shaft 4 has such a cross-sectional shape that
inscribes, at each of the edges thereof, the inner
circumferential wall surface of the valve chamber 5 so that
an axially straight gap (floor channel) is formed between
each of axial sides of the valve shaft 4 and the inner
circumferential wall surface of the valve chamber 5 rod by
turned on a lathe, so as to provide a wide channel 19.
In order to situate the cylindrical first magnet MS
attached to the rear end of the valve shaft 4 at the center
of the valve chamber 5 while havlng the fluid channel 19 in
the valve chamber 5, it is necessary that the valve shaft 4
be in sliding contact at the outer circumferential surface
thereof with the inner wall of the valve chamber 5 and, at
the same time, a portion of such outer circumferential
surface of the valve shaft 4 be separated by a gap from the
inner wall of the valve chamber 5.
Although this structure may be obtained by using a round
metal rod as the valve shaft 4 and cutting a plurality of
recessed grooves into the circum~erential surface thereof
- 15 -
/ , ,,
131~8
along the longitudinal direction, this increases the cost for
cutting the recessed grooves. On the other hand, the
fabrication cost can be reduced greatly in the providing
simple lathe work of merely chamferring the corners of a
square rod aligned with the inner diameter of the valve
chamber 5 as shown in FIG. 3.
As shown in FIG. 3, the valve seat 10 is secured to the
hollow body 16 by means of a flat-head screw 20, while the
cylindrical tube 18 is secured to the hollow body 16 by means
of a flat-head screw 21.
A valve body 2 having a sheet-like packing 22 embedded
therein is formed at the top end of the valve shaft 4, so
that the surface of the sheet-like packing 22 is abutted
under pressure against a protrusion lOa formed on the valve
seat 10 along the circumference of the fluid port lA in a
closed state of the valve in which the valve body 2 is
abutted against the valve seat 10.
Since the sheet-like packing 22 of the valve body 2 to
be abutted against the valve seat 10 is embedded at the top
end of the valve ehaft 4, no excess pressure is applied to
the ~heet-like packing 22 and, accordingly, it is possible to
improve sealing performance by using a flexible rubber
packing, as well as moderate abrasion or damage thereof to
impro~e the durability.
Then, a piston having the second cylindrical magnet ML
is slidably fitted over the outside of the cylindrical tube
18 fixed to the hollow body 16 by means of the flat-top screw
21. A pair of wearing members 23 and 23 which are in contact
with the outer ciraum~erential surface of the cylindrical
- 16 -
.~ .
131~8
tube 18 are fitted to the inside of the piston 7 on both of
the forward and rearward ends thereof relative to the
cylindrical magnet ML, so that abrasion of the cylindrical
magnet ML caused by sliding movement of the piston 7 can be
prevented.
A spring 24 is fitted over the outer circumference of
the piston 7 for resiliently biasing the piston 7 in the
direction of closing the valve and, further, a cylindrical
cover 25 that constitutes a barrel for the cylinder 8 is
covered over the outside of the spring. The cylindrical
cover 25 has a flange 25a formed at the rear end thereof for
tightly receiving the end of the cylindrical tube 18. The
~lange 25a is retained by a connection member 26 to be
~crewed into the cylindrical tube 18 and clamped while being
fitted over the hollow body 16.
Upon conducting maintenance and checking or replacing
parts ~or the automatic valve with such a structure, all of
the parts can be removed easily by merely detaching the
connection member 26 screwed into the cylindrical tube 18 and
then detaching the cyllndrical cover 25 fitted over the outer
clrcumference o~ the hollow body 16.
The flange 25a has a discharge hole 27 perforated
therein for discharging air from the cylinder 8 when
pressurized air for driving the piston 7 is supplied from the
fluid port 9 perforated in the hollow body 16. As shown by
the cross sectional views of FIG. 1 and o~ FIG. 4, the
discharge hole 27 comprises a round-about channel 27a
consicting of a recessed groove cut into an arcuate shape
along the inner circumferential sur~ace of the flange 25a,
which i5 in close contact with the outer circumferential
- 17 -
.~,,
1319~
surface of the cylindrical tube 18, an air discharge channel
Z7b consisting of a perforation formed from the inside of the
recessed groove of the round-about channel 27a toward the
outer circumferential surface of the cylindrical cover 25,
and an air discharge channel 27c consisting of a perforation
formed from the inside of the recessed groove of the round-
about channel 27a to the inside of the cylinder 8 in a
direction diametrically opposite to the air discharge channel
27b in relation with the cylindrical tube 18.
Then, when the piston 7 is caused to move slidably by
pressurized air supplied from the port 9 against the
resiliency of the spring 24 in the direction of opening the
valve, the air in the cylinder 8, pressurized by the piston
7, is passed from the air discharge channel 27c opened to the
inside of the cylinder 8 through the roundabout channel 27a
bent in an arcuate form and the air discharge channel 27b,
and then released to the outside of the cylinder 8.
In this way, since the air discharge hole 27 has ~uch a
shape of communicating the air discharge channel 27c opened
to the inside of the cylinder 8 with the air discharge
channel 27b opened to the outside of the cylinder 8 by way of
the round-about arcuate channel 27, when cleaning solvent is
blown onto the surface of the automatic valve for cleaning
off contaminations such as paint, etc. deposited on the
~urface, intrusion of the solvent blown onto the inside of
the cylinder 8, which would otherwise deteriorate the rubber
packing etc., can surely be prevented.
That is, since the solvent entering from the outside of
the cylinder 8 through the air disaharge channel 27b is
hindered by the round-about arcuate channel 27 and can not
- 18 -
~", ~ ,.
1319~8
reach as far as the discharge channel 27c, it is no worry
that the packings such as 0-rings disposed in the cylinder 8
may be deteriorated by the solvent.
The air discharge hole 27 can be fabricated easily by at
S first forming the round-about channel 27a by cutting a
recessed groove into the inner circumferential surface of the
flange 25a, perforating the discharge channel 27b extended
from the outer circumferential surface of the flange 2sa to
the round-about channel 27a, perforating the air discharge
channel 27c by forming a hole of a predetermined length from
the inside of the round-about channel 27a toward the
direction diametrically opposite to the air discharge channel
27b and forming a hole so as to be in communication with the
above-mentioned hole from the inside of the cylinder 8.
In FIG. 1, a holder 28 for mounting the automatic valve
to the manifold, etc. of a color-change device (not
illustrated) is interposed between the hollow body 16 and the
valve seat 10 and secured together with the valve seat 10 to
the hollow body 16 by means of the flat-head screw 20.
The connection member 26 is connected to a paint pipeway
in communication with a paint supply source ~not
illustrated), and has a port lB formed therein for flowing
the paint supplied through the paint pipeway into the valve
chamber 5.
Thus, flow ports lA and lB for the paint are formed on
both axial ends of the channel 8, while being opposed to both
of the top and rear ends of the valve shaft 4, respectively.
-- 19 --
13~9~8
The ON-OFF operation of the automatic valve described
above is to be explained below.
In the present embodiment, the respective ring magnets
3, 3,-constituting the first cylindrical multi-layered magnet
MS and respective ring magnets 6, 6,-constituting the second
cylindrical multi-layered magnet ML are stacked as described
above and shown in FIG. 2 such that identical N poles or
identical S poles face each other in each pair of axially
adjacent ring magnets. Accordingly, a great quantity of
magnetic fluxes generated, for example, from the two N poles
of the axially adjacent ring magnets 3, 3 are concentrated
toward the two S poles of the axially adjacent pair of ring
magnets 6, 6-radially opposed therewith by way of the
cylindrical tube 18, and strong magnetic attraction force is
exerted between the cylindrical multi-layered magnets MS and
ML.
That is, as in the case of the cylindrical magnets MS
and ML in this embodiment, when the plurality of ring magnets
are stacked su¢h that the identical poles are faced to each
other in each pair of axially adjacent rings, a great
quantity o~ magnetic ~luxes are generated, ~or example, from
the two opposed N poles in each axially ad~acent pair o~ ring
magnets 3, 3, constituting the cylindrical magnet MS, and the
magnetic fluxes are concentrated toward the two S poles of
the corresponding axially adjacent pair of ring magnets
6, 6,-in the cylindrical magnet ML by way of the cylindrical
tube 18. Accordingly, the magnetic attraction force exerted
between the cylindrical magnets ML and MS is extremely
increased.
Accordingly, although a gap i~ formed between the outer
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circumference surface of the cylindrical magnet MS and the
inner wall of the valve chamber 5, for constituting the
channel 19, to thereby space the cylindrical magnets MS and
ML apart slightly, since these magnets MS and ML attract with
each other by an extremely intense magnetic force, the valve
shaft 4 attached with the cylindrical magnet MS can surely be
moved slidingly in the direction of opening the valve against
the resiliency of the spring 24.
Further, in a state wherein the valve is closed as shown
in FIG. 1, in which the valve body 2 formed on the top end of
the valve shaft 4 is abutted against the valve shaft 10,
since the respective ring magnets 6, 6-in the cylindrical
magnet ML are 80 situated that they are slightly deviated
axially relative to the respective radially opposed ring-
magnets 3, 3,-constituting the cylindrical magnet MS in the
direction o~ closing the valve, with the polarity being
di~erent between each of radially opposed pair of ring
magnets 3 and 6, the valve shaft 4 attached with the
cylindrical magnet MS is strongly energized by the component
of the magnetic attraction force exerted downwardly (in the
drawing) ~rom each of the ring magnets 6, 6,-to each of the
ring magnet~ 3, 3,-in the direction o~ closing the valve.
Thus, the valve body 2 formed at the top end o~ the
valve shaft 4 can be maintained in a completely closed state
even if the back pressure of a fluid (paint ) e.g., is
exerted from the port lA.
Accordingly, in the case of using the automatic valve of
this embodiment as the color-change valve of a multi-color
coating apparatus, it i5 possible to prevent the valve body 2
from separating ~rom the valve seat 10 by the pres~ure of
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131~8
paint of different color exerted from the port lA and prevent
paint of different color from intruding into the valve
chamber 5, thereby causing mixing of paint colors.
Next, in the case of opening the automatic valve,
pressurized air is supplied from the port 9 perforated in the
hollow body 16. This causes the piston 7 fitted with the
cylindrical magnet ML to move slidingly by the pressure of
air against,the resiliency of the spring 24 in the direction
of opening the valve.
Thus, the cylindrical magnet MS magnetically attracted
by the cylindrical magnet ML fitted to the piston 7 is caused
to move 61idingly along with the movement of the piston 7 in
the direction of opening the valve, by which the valve body 2
~ormed at the top end of the valve shaft 4 is separated from
the valve seat 10 to open the port lA.
When the piston 7 is caused to slide in the direction of
opening the valve, air in the cylinder 8 is pressurized by
the plston 7 and discharged externally through the air
discharge port 27.
The automatic valve can be closed merely by interrupting
the supply of the pres~urlzed air from the port g, in which
the pi~ton 7 is caused to ~lide automatically in the
direction o~ closing the valve by the resiliency of the
spring 24 to return to the state shown in FIG. 1.
In the case o~ cleaning the inside o~ the valve chamber
5 of the automatic valve when the valve i8 being used as a
colorchange valve, the valve i8 opened and a cleaning solvent
is introduced through the port lB, passed through the channel
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:'
1 3 ~ 8
19 in the valve chamber 5 and then discharged from the port
lA. Thus, the paint deposited and remaining on the inner
wall surface of the valve chamber 5 and the surface of the
valve shaft 4 and of the cylindrical magnet MS can be
completely cleaned and removed with no color residue of the
paint remaining. Thus, the valve does not suffer from
solidification of paint remaining between the outer
circumferential surface of the cylindrical magnet MS and the
inner wall surface of the valve chamber 5, which would
otherwise hinder the sliding movement of the cylindrical
magnet MS.
Although explanations have been made referring to the
case shown in FIG. 1, wherein the automatic valve is
constituted as a two-way valve, the valve is not restricted
only thereto but it may be a three-way valve, for example, as
shown in FIG. 5.
Specifically, FIG. 5 is a cross sectional view
illustrating another embodiment of the automatic valve
a¢cordlng to the present invention, in which another fluid
port lC is further disposed in addition to the fluid ports lA
and lB.
The port lC i5 perforated in the hollow body 16 and
connected, for example, with a paint supply source (not
illu~trated). When the automatic valve is in a closed state,
as shown in FIG. 5, a paint supplied from the paint supply
~ource and introduced through the port lC i8 circulated by
way of a route such that it flows through the channel 19 in
the valve chamber 5 toward the port lB formed at a position
axially opposite to the port lA, flow~ out from the port lB
and then is returned to the paint supply source.
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1319~8
Valve bodies 2, 2' are formed at both of the top and the
rear ends of a valve shaft 4 for alternately closing the
ports lA and lB, respectively. The valve body 2' has such a
structure that a sheet-like packing 22' is embedded in the
end of a nut 13 that is screw-coupled over a bolt 12
protruded from the rear end of the valve shaft 4 like that in
the valve body 2.
Thus, when the automatic valve is opened, the port lB
through which paint flows from the port lC to the inside of
the valve chamber 5 toward the paint supply source is now
closed by the valve body 2' and, at the same time, the port
lA closed until then by the valve body 2 is now opened and
the paint ~lowing from the port lC to the inside of the valve
5 is discharged out of the port lA and supplied to the
coating apparatus.
In the drawing, since other components or members are
the same as those shown in FIG. 1, they carry the same
re~erence numerals a~ in FIG. 1 and detailed explanations of
them are omitted.
As ha5 been described above, ln the automatic valve
a¢cordinq to the present invention, since the ~irst
cylindrical multi-layered magnet o~ a smaller diameter
attached to the rear end of the valve shaft and slidably
enhoused axially within the valve chamber and a second
cylindrical multi-layered magnet of a greater diameter
disposed axially slidably to the outside o~ the valve chamber
~or causing the valve sha~t to move slidingly by the magnetic
attraction ~orce, each comprising a plurality of ring
magnets, are stacked such that respective axia~ly adjacent
magnets are opposed to each other with their identical
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131~8
magnetic poles being faced to each other, the magnetic
attraction force exerted between both of the cylindrical
magnets is increased extremely. In addition, since the
respective ring magnets constituting the second cylindrical
magnet are so situated that they are slightly deviated
axially in the direction of closing the valve relative to the
respective radially opposed ring magnets of the first
cylindrical magnet, the valve shaft attached the cylindrical
magnet is energized in the direction of closing the valve by
the magnetic attraction force exerted between both of the
magnets. Accordingly, the valve formed at the top end of the
valve shaft can be maintained in a completely closed state
against the backward fluid pressure exerted thereon.
Furthermore, since the piston including the ~econd
cylindrical magnet is energized by the resiliency of the
spring disposed in the cylinder in the direction of closing
the valve, only one fluid port is necessary for pressurized
air for driving the piston, and the number of air hose
piepways ~or supplying the pressurized air i8 reduced thereby
enabling one to decrease the installation cost and the
lnstallation space.
Furthermore, since the discharge hole used for directly
discharging the air ~rom the cylinder to the outside when the
pres~urized air is supplied to drive the piston has such a
shape that the discharge channel opened to the inside of the
cylinder and the discharge channel opened to the outside of
the cylinder are in co~munication with each other by way of a
round-about bent channel, i~ a cleaning solvent is blown onto
the sur~ace o~ the automatic valve, there is no worry that
the solvent will in~iltrate into the cylinder to deteriorate
the packings, etc., made o~ rubber.
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1319~g8
Furthermore, in the case of cleaning a paint remaining
in the valve chamber with a solvent, etc., since the solvent
entering, for example, from the fluid port on the side of the
rear end of the valve shaft is passed through the channel
formed between the outer circumferential surface of the valve
shaft and of the first cylindrical magnet attached to the
rear end of the shaft and the inner wall surface of the valve
chamber and then discharged out of the port on the side of
the top end of the valve shaft, paint deposited on the
surface of the valve shaft and of the first cylindrical
magnet and to the inner wall surface of the valve chamber can
be completély eliminated with no color residue, which can
surely prevent the problem that paint remaining between the
outer circumferential surface of the first cylindrical magnet
and the inner wall surface of the valve chamber solidifies to
hinder sliding movement of the cylindrical magnet.
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