Note: Descriptions are shown in the official language in which they were submitted.
P-556 8~86-265D
This application is divided out of copending
Canadian application ~o. 419,756, filed January 19, 1983.
The subject invention relates to a hydraulic control
assembly or package for use in a marine steering system.
Tyically, a marine steering system includes a steering or helm
pump attached to a steering wheel for directing fluid to oppos-
ite ends of an actuating cylinder which, in turn, actuates the
rudder to effect steering of the boat.
~ s will be appreciated, there is quite a distance
between the helm steering pump and the hydraulic actua-ting
cylinder for moving the rudder. Typical of a prior art system
is one which includes a reservoir positioned somewhere on the
boat between the steering helm pump and the actuating cylinder.
Fre~uently, the reservoir is pressurized with air so that the
entire system is pressurized. In such systems air or gas may
accummulate in the actuating cylinder and must be released or
bled off. Typically, manually actuated pressure relief valves
are attached to each end of the cylinder and, when opened,
relieve the gas at the end of the cylinder, which gas passes to
the atmosphere or back to the reservoir. During the bleeding
operation, the reservoir is disconnected from the system and,
after the bleeding is completed, the relief valves are closed,
putting the reservoir back in-to the system.
The prior art systems also include various control
valves for directing the fluid flow between the steering helm
pump and the actuating cylinder.
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Most such steering systems also include various
filters for removing contaminants from the hydraulic fluid.
Such filters frequently restrict the hydraulic fluid flow
and, therefore, increase the effort required for steering.
According to the present inven-tion -there is
provided a hydraulic control assembly for use in a marine
steering system of the type having at least two steering
pumps with each having port and starboard fluid outlets and a
return inlet, a steering cylinder with a piston therein and
port and starboard inle-ts for hydraulically moving the piston
back and forth in the cy].inder in response to fluid delivered
:~rom the pumps, control valve means lnterconnecting said port
outlets of said pumps to said port inlet of said steering
cylinder and said starboard outlets of said pumps to said
starboard inlet of said steering cylinder and including a
return line connected to said return inlets of said pumps for
controlling fluid flow between the pumps and the steering
cylinder, said assembly being characterized by including flow
divider means between said control valve means and said
~0 steering pumps for preventing the nonactive steering pump
from motoring in response to steering fluid output of the
active steering pump while allowing a limited amount of the
steering fluid output to flow to the nonactive steering pump,
the flow divider means including a first shuttle-tee check
valve having a first valve passage interconnecting the port
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outlets of the steering pumps and a first outlet connected -to
the control valve means with a first valve member movable
back and forth to close the first valve passage to -the por-t
outlet of the inactive pump in response to fluid output from
the port outlet of the active pump and a second shuttle-tee
check valve having a second valve passage interconnec-ting the
starboard outlets of the steering pumps and a second outlet
connected to the control valve means with a second valve
member movable back and forth to close the second valve
passage to the starboard outlet of the inactive pump in
response -to fluid output from the starboard ou-tlet of the
active pump.
The present invention will now be described by
reference to the following detailed description when
considered in connection with the accompanying drawings
wherein:
FIGURE 1 is a schematic view illus-trating a marine
steering system,
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FIGURE 2 is an enlarged cross-sectional view taken
substantially along line 2-2 of FIGURE 4;
FIGURE 3 is a cross-sectional view through the valve body
taken subs-tantially along line 3-3 of FIGURE 2;
FIGURE 4 is a side elevational view taken substantially
along line 4-4 of FIGURE 2 but of a smaller scale and partially
broken away and in cross section, and
FIGURE 5 is a schematic view showing a steering assembly
of the suject invention including a plurality of steering pumps.
~ marine steering system is generally shown at 10 in
FIGURE 1. The steering system 10 is of the type havi.ng a helm
~teering pump 12 with port and starboard Eluid outlets 14 and
16, respectively, and return inlet 18.
The steering system 10 includes an actuating or steer-
ing cylinder 20 with an actuating piston 22 slidably disposed
therein with port and starboard inlets 2 4 and 26, respectively,
for moving the piston 22 back and forth in the cylinder 20 in
response to fluid delivered from the steering pump 12.
The hydraulic control assembly is generally shown at
30. The assembly includes a reservoir for supplying fluid to
the steering system 10. The reservoir includes a tube 32,
preferably a cylinder made of clear acrylic having first and
second open ends. A metal cap member 34 is in sealing engage-
ment with the first or top end of the tube 32. A valve body,
generally indicated at 36, is in sealing engagement with the
second or bottom end of the tube 32 to define the fluid
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reservoir.
The hydraulic control assembly 30 also includes
control valve means for controlling the fluid flow in the
system 10 and the valve body 36 includes or houses the control
valve means.
The cap member 34 includes a cylindrical or circular
insert portion 38 extending into and in sealing engagement
with the interior of the tube 32 adjacent the top end thereof.
More specifically, an annular or circular seal 40 is disposed
between the central insert 38 and the interior wall of the
acrylic tube 32. In a similar
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fashion, the valve body 36 includes an insert por-tion 42
extending into and in sealing engagement with the interior
of the tube 32 adjacent the bottom end thereof, there
being an annular seal 44 disposed between the central
5 insert portion 42 and the interior wall of the acry]ic
tube 32. The cap member 34 includes an abutment flange 46
which is square or four-sided to define round corners.
The abutment flange 46 extends radially from the insert
portion 38 and engages the end surface of the top of the
10 tube 32. In a similar fashionl the valve body includes an
abutment flange 48 which is square or four-sided to define
round corners and extends radially from the inser-t portion
42 thereof to engage the bottom end surface of the tube
32.
A plurality of tie rods 50 interconnect t,he cap
member 34 and the valve body 36 for urging the cap member
34 and the valve body 36 into engagement wih -the top and
bottom ends of the tube 32. There are four tie rods 50
and each tie rod extends through one of the corners of the
20 abutment flanges 46 and 48. The tie rods are threaded at
each end and include nuts for tensioning the respective
tie rods 50.
The valve body 36 includes a central metal portion 52
extending from the abutment flange 48 thereof in a
25 direction away from the bottom or second end of the tube
32. The valve body also includes a pair of identical side
portions 54 extending along opposite sides of the central
portion 52 and connected thereto by bolts 56, one of which
is illustrated in FIGURE 2. The side portions 54 are
30 preferably made of a plas-tic, such as nylon. Thus, the
side portions 54 are removably attached to the central
portion 52 by bolts 56.
The central portion 52 includes a reservoir inlet
passage 58 extending to a first opening into the tube 34.
35 A portion of the reservoir inlet passage 58 is plugged by
a threaded plug 60. A first control tube 62 is threaded
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into the opening of the reservoir inlet passage into the
tube 32. The central portion 52 also includes a pump
outlet passage extending from a second opening into the
tube 32 to the pump return outle-t line 18. A second
5 control tube 66 is threaded into the opening for the pump
outlet passage. The cap 34 forms the top of the reservoir
and the valve body 36 forms the bottom of the reservoir.
Accordingly, the control tubes 62 and 66 ex-tend upwardly
from the bottom of the reservoir tank into the reservoir.
10 The first control tube 62 which provides an inlet into the
reservoir tank of hydraulic fluid from the system is
longer in length than the second con-trol tube 66 forming
the exit tube to the steeriny pump inlet 18. Accordingly,
contaminants in the hydraulic fluid entering the tube 62
15 will be dispersed -throughou-t -the hydraulic fluid in the
reservoir tank to fall to -the bottom or settle on the
bottom of the reservoir about the control tubes 62 and 66
so as to be prevented from entering the ~ump outlet
control tube 66. In other words, the end of the tube 66
20 is high enough above the bottom of the tank so that
contaminants settled on the bottom of the tank will not
enter the tube 66 and the system. The arrangement of the
tubes 62 and 66, therefore, eliminates the need for a
filter in the system which could increase the steering
25 resistance.
Each of the side portions 54 includes a pump inlet
passage 68 communicating with the central portion 52 for
receiving fluid from- the pump outlets 14 and 16 7
respectively. Each of the side portions 54 also includes
30 a cylinder passage 70 for establishing fluid communication
between the central portion 52 and one of the steering
cylinder inlets 24 and 26. A check valve 72 is disposed
in each cylinder passage 70 in each of the side portions
54.
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The central portion 52 has a shuttle bore 74
extending completely therethrough between the side
portions 54 and communicating with the pump inlet passages
68. A shuttle valve means or members 76 are slidably
5 disposed in the shuttle bore 74 for controlling the fluid
flow therethrough. The central portion also has a spool
bore 78 extending therethrough between the side portions
54 and communicating with the cylinder passages 70. A
spool valve means or member 80 is slidably disposed in the
10 spool bore to perform a controlling function.
Each of the side portions 54 includes a first pocket
82 therein about the cylinder passage 70 and facing the
spool bore 78 at the end thereof. A first valve seat 84
ls disposed in each pocket 82 and engages the side of the
1~ central portion 52. The check valve 72 includes a round
ball disposed in the cylinder passage 70 with a spring
associated therewith and disposed around a projection in
the side portion for reacting between the side portion 54
and the ball for urging the ball into and in sealing
20 engagement with the associate valve seat 84.
As alluded to above, the side portions 54 are
preferably made of a plastic, such as nylon, and include
metal connectors or fasteners 86 at each of the pump inlet
passages 68 and at each of the cylinder passages 70. Each
25 connector or fitting 86 has one end completely embedded in
the plastic material of the side portions 54 with the
other end extending therefrom and adapted by nuts to be
connected to a fluid line. Specifically, the connectors
are of the type into which the end of a tube is inserted
30 with the connectors being tightened down to force an
annular flexible seal into engagement with the exterior of
the tube. As shown, each of the connectors includes an
insert 88 which prevents contaminants from entering into
the system dùring shipment, the insert 88 being removed
35 prior to attaching the end of a tube to the connector. A
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similar connector 90 threadedly engages the central
portion 52 of the valve body and similarly attaches to a
fluid line 18 leading to the helm pump 12.
The central portion 52 has a relief cavity 92
5 extending therethrough between the side portions 54. Each
side portion 54 has a relief passage 94 communicating
between the cylinder passage 70 and the relief cavity 92
in the central portion 52. Each side portion 54 has a
second pocket therein about the relief passage 94 and
10 facing the relief cavity 92 for receiving a second valve
seat 96. Each valve seat 96 is disposed in the pocket and
engages the side face of the central portion 52. ~ relief
valve assembly 92 is disposed in each of the opposite ends
of the relief cavity 92 and lncludes a spring biased ball
15 engaging the second valve seat 96.
The central portion 52 includes the passages 100 and
102 communicating between the shuttle bore 74 and the
spool bore 78 with the openings thereof being controlled
by the shuttle valve members 76. As described
20 hereinbefore, a portion of the reservoir inlet passage 58
is a passage extending between the relief cavity 92 and
the reservoir inlet.
The spool valve 80 includes extensions extending from
each end thereof for opening the check valves 72.
As alluded to hereinbefore, the reservoir is closed
and includes filling means defined by the plug 104 and the
one-way inlet valve 106 in the top or cap 34 of the
reservoir for filling the reservoir with hydraulic fluid
and for pressurizing the reservoir with a gas such as air.
30 The plug 104 may be threaded out of engagement with the
cap 34 for introducing hydraulic fluid into the reservoir.
The pressure inlet 106 is of the type utilized with
pneumatic tires, such as automotive tires, for inflating
tires. Also disposed in the cap member 34 is a pressure
35 gauge means 108 for indicating the pressure in the system
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P-556
Instead of the pressure gauge 108 being connected to
the cap member 34 or, in addition to the pressure gauge
108, a pressure gauge 108', as shown in FIGURE 1, may be
connected to the return line to the steering pump 12 with
5 the gauge 108' actually being disposed on the instrument
panel whereby the boat operator has an immediate
indication of the system pressure.
The assembly also includes the brackets 110 which are
held in place by tie rods 50 for attaching the assembly or
10 mounting the assembly to a support structure.
The operation of the system is best illustrated in
FIGURE 1 wherein the pump 12 is providing pressure in the
line 16 to the passage 68 in the valve body 36. The fluid
pressure in the passage 68 acts upon the right-h~nd valve
15 member 76 rnoving it to the left as indicated. Fluid
pr~ssure Erom the line 68 passes through the passage lO0
to the spool bore 78. I'he fluid pressure in the bore 78
moves the spool valve 80 to the left whereby the check
valve 72 on the left is opened, allowing return fluid flow
20 from the cylinder 20 through the passage 102 on the left
and into the tube 62 of the reservoir. Pressure on the
right of spool valve 80 also opens the check valve 72 on
the .ight to allow flow through the conduit 26 to the
hydraulic cylinder 20 thereby moving the piston to the
25 left, as illustrated. The pump 12, of course, is being
fed hydraulic fluid from the reservoir through the tube 66
and the pump inlet 18.
If the direc-tion of steering is reversed, the valves
all move to the right in response to fluid pressure
30 produced by the pump 12 in the pump outlet 14 and the
components all work in reverse.
Although not shown schematically in FIGURE 1, the
system does include high pressure relief valves 98 which
open the cylinder passages 70 to the relief cavity 92 and
35 the passage 58 extending back to the reservoir inlet tube
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62. In other words, if the pressure in the cylinder
passage 70 becomes too high, the relief valves 9~ will
relieve the pressure to the reservoir.
The assembly shown schematically in FIGURE 5 includes
5 the hydraulic control assembly 30~ as described above,
associated with the steering cylinder 20 with the port and
starboard inlets 24 and 26. The system in FIGURE 5
includes a second steering pump 12' having the port and
starboard fluid outlets 14' and 16'. The line 18 is
10 connected to the return inlet of the pump 12' with the
pump 12' connected by line 18' to the return inlet of
steering pump 12. The assembly of FIGURE 5 includes flow
divider means between the control valve means 36 and the
steering pumps 12 and 12' for preventing the nonactive
15 steering pump from motoring in response to steering fluid
output of the active steering pump while allowing a
limited amount of the steering fluid output to flow to the
nonactive steering pump. More specifically, the flow
divider means includes a first shuttle-tee check valve 120
20 having a first valve passage interconnecting the port
outlets 14 and 14' of the steering pumps 12 and 12' and a
first outlet 121 connected to the control valve means 36.
A first ball valve member 122 is movable back and forth in
the first valve passage to close the first valve passage
25 to the port outlet 14 or 14' of the inactive pump in
response to fluid output from the port outlet 14 or 14' of
the active pump. In a similar fashion, the flow divider
means includes a second shuttle-tee check valve 124 having
a second valve passage interconnecting the starboard
30 outlet 16 and 16' of the steering pumps 12 and 12' and a
second outlet 125 connected to the control valve means 36.
A second ball valve member 126 is movable back and forth
in the second valve passage to close the second valve
passage to the starboard outlet 16 or 16' of the inactive
35 pump in response to fluid output from the starboard outlet
16 or 16' of the active pump.
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P-556
In addition, the flow divider means includes a first
bypass passage 127 interconnecting the port outlets 14 and
14' for allowing a restricted flow of fluid to bypass the
first shuttle-tee check valve 120. Similarly, a second
5 bypass passage 128 interconnects the starboard outlets 16
and 16' for allowing a restricted flow of fluid to bypass
the second shuttle-tee valve 124. Each of the bypass
passages 127 and 128 includes a calibrated flow control
restriction to limit the volume flow rate to a
10 predetermined range.
The two steering pumps 12 and 12' may be two pumps
connected to a steering wheel or one of the steering pumps
may be associated with an auto pilot. Assuming that the
steering pump 12 is the active pump by being manually
15 actuated for producing steering fluid pressure in the
starboard outlet 16, the fluid will flow into the shuttle-
tee check valve 124 moving the valve member 126 to the
left, as illustrated, for preventing fluid flow through
the shuttle-tee check valve 24 and into the starboard
20 outlet line 16' leading to the second steering pump 12'.
This will prevent the second steering pump 12' from
motoring or turning in response to the output of the first
steering pump 12. The output from the first steering pump
12 will pass through the shuttle-tee check valve 124 and
25 out the outlet 125 thereof to the passage 68 in the
control valve means 36, as hereinbefore described. At the
same time, a restricted flow passes through the bypass
passage 128 and the calibrated restriction 130 to the
starboard outlet 16' of the nonactive pump 12'. This
30 compensates for the residual pressure in the lines,
particularly when the steering direction is changed
frequently. If the active steering pump 12 is rotated in
the opposite direction, the system would operate in
reverse with'the check ball member 122 moving to the
35 right~ Additionally, should the steering pump 12' become
the active pump for an output in the starboard outlet 16',
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the check ball member 126 would move to the right and the bypass
flow in the passage 128 would be in the reverse direction from
outlet 16' to outlet 16.
In actual practice, when using 300 psi in the system,
the restrictions 130 have been calibrated to allow a rate of flow
in the predetermined range of between 50 and 150 milliliters per
minute. If the bypass leakage in the passages 127 and 128 is
too small, the two shuttle members or plungers 76 in the control
valve means 36 could remain closed on both sides at the same
time. If the bypass Elow is too high, the nonoperated or inactive
skeerin~ pump will motor or turn in response to activation of the
other steering pump.
By utilizing the concept shown in FIGURE 5, the steering
pumps 12 and 12' need not have any valves whatsoever associated
with them to control flow therethrough and soft lines may be used
in the system.
