U.S. patent number 3,654,889 [Application Number 05/075,909] was granted by the patent office on 1972-04-11 for hydraulic system for a boat drive.
This patent grant is currently assigned to AB Volvo Penta. Invention is credited to Karl Abdon Bergstedt.
United States Patent |
3,654,889 |
Bergstedt |
April 11, 1972 |
HYDRAULIC SYSTEM FOR A BOAT DRIVE
Abstract
A hydraulic system for steering and tilting an outboard drive
unit for a boat including a pump, a steering sub-system including a
double acting cylinder and piston connected to provide steering
movement to a steerable part of the unit and provided with
hydraulic liquid from the pump, and a trimming and tilting
sub-system including a cylinder and piston assembly provided with
liquid from the steering sub-system. Manual valves control tilting
and trim positioning of the unit, and steering, while pressure
relief valves are arranged to prevent damage to the unit and system
upon excess steering control, striking of external objects, and the
like.
Inventors: |
Bergstedt; Karl Abdon
(Goteborg, SW) |
Assignee: |
AB Volvo Penta (Gothenburg,
SW)
|
Family
ID: |
22128697 |
Appl.
No.: |
05/075,909 |
Filed: |
September 28, 1970 |
Current U.S.
Class: |
440/61R; 440/75;
440/57; 440/61A |
Current CPC
Class: |
B63H
20/002 (20130101); B63H 20/22 (20130101); B63H
20/12 (20130101); B63H 20/10 (20130101) |
Current International
Class: |
B63H
25/42 (20060101); B63H 25/00 (20060101); B63h
025/42 () |
Field of
Search: |
;115/35,41,41HT,34 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Buchler; Milton
Assistant Examiner: Rutledge; Carl A.
Claims
What is claimed as new and what it is desired to secure by Letters
Patent of the United States is:
1. In a boat drive unit including a steerable and tiltable outboard
power leg, a mounting member for said leg fixed to the boat, said
leg comprising a propeller housing including an underwater portion
provided with a propeller, a support member and means supportedly
connecting said propeller housing to said support member for
rotation of said housing on a generally upright steering axis,
means supportedly connecting said support member to said mounting
member for tilting of said leg on a generally horizontal tilt axis
in a rearward direction of increasing tilt angle and in a forward
direction of decreasing tilt angle, a hydraulic control system for
said leg comprising, a hydraulic expansible chamber device spanning
said tilt axis and operatively connected between said mounting
member and said support member, a steering cylinder assembly
comprising a cylinder fixed to said support member and double
acting piston means disposed in said cylinder, means operatively
coupling said piston means to said propeller housing offset from
said steering axis, a source of hydraulic liquid under pressure, a
sump for supplying liquid to said source, steering control means
connecting between said source and said cylinder assembly including
a valve and an outlet conduit, said valve having a rest position in
which said source is connected to said outlet conduit, a port
steering position in which said source is connected into one of
said chambers and said outlet conduit is connected to the other of
said chambers, and a starboard steering position in which said
source is connected into said other chamber and said outlet conduit
is connected to said one chamber, a three way manually controlled
valve connected to said conduit to receive pressure liquid
therefrom and in a first position of said three way valve to supply
said fluid to a pump-up side of said expansible chamber device to
power tilt said leg in said rearward direction, in a second
position to seal off said side thereby to restrain said leg against
forward tilting and to connect said conduit to said sump, and in
its third position to connect said side and said conduit to said
sump thereby to release said leg for forward movement on said
axis.
2. In a boat drive unit including a steerable and tiltable outboard
leg, a mounting member for said leg fixed to the boat, said leg
comprising a propeller housing including an underwater portion
provided with a propeller, a support member and means supportedly
connecting said propeller housing to said support member for
rotation of said housing on a generally upright steering axis,
means supportedly connecting said support member to said mounting
member for tilting of said leg on a generally horizontal tilt axis
in a rearward direction of increasing tilt angle and in a forward
direction of decreasing tilt angle, a hydraulic control system for
said leg comprising, a hydraulic expansible chamber device spanning
said tilt axis and operatively connected between said mounting
member and said support member and adapted to tilt said leg upon
the supplying of hydraulic fluid under pressure thereto, double
acting hydraulic cylinder and piston means operatively coupled
between said support member and said propeller housing, said last
means including two conduits and operative upon supply of pressure
liquid into one of said conduits to swing said propeller housing to
port and to supply pressure liquid through said other conduit, and
upon supply of pressure liquid into said other conduit to swing
said propeller housing to starboard and to supply pressure liquid
through said one conduit, a hydraulic liquid sump, a hydraulic
pressure pump connected to said sump, a fluid return line connected
into said sump, steering control valve means connected to said
pump, to said conduits and to said return line, said valve means
being operative selectively (1) to supply pressure liquid from said
pump to said one conduit and to connect said other conduit to said
return line, (2) to supply pressure liquid to said other conduit
and to connect said one conduit to said return line, and (3) to
seal said conduits and to supply pressure liquid from said pump to
said return line thereby to fix said propeller housing with respect
to said support member, and a tilt control valve interposed in said
return line operable into selective positions (1) to divert
pressure liquid therefrom into said expansible chamber device
thereby to tilt said leg, (2) to seal off said device thereby to
retain the leg in its position of tilt, and (3) to connect said
device to said sump thereby to reduce the tilt angle of said
leg.
3. In a marine propulsion mechanism, the combination with mounting
bracket means adapted to be secured to a boat and a propulsion unit
pivotally connected to the mounting bracket means on a horizontal
transverse axis to provide for tilt movement of the unit in a
generally vertical plane, an extensible power tilt unit comprising
a double acting hydraulic liquid filled cylinder having a piston
therein dividing said cylinder into first and second enclosed
chambers, a piston rod connected to said cylinder through said
second chamber thereof, said tilt unit being connected between said
bracket means and said propulsion unit spanning and below said axis
thereby to tilt up said propulsion unit upon extension thereof and
to be extended upon tilting up of said propulsion unit from the
imposition of an external force thereto, a pressure relief valve
having a predetermined operating pressure connected from said first
chamber to said second chamber, means including a control valve, a
liquid sump and a pump to supply hydraulic liquid from said sump
under pressure from the pump outlet, a shut off valve disposed
between said second chamber and said pressure relief valve, a
second pressure relief valve operative at a pressure substantially
greater than the operative pressure of said first relief valve
connected from said second chamber to said first chamber, said
control valve having a first position connecting the outlet of said
pump to supply pressure liquid to said first chamber, a second
position to seal off said first chamber thereby to restrain said
unit against contraction and to connect said pump outlet to said
sump, and a third position connecting said first chamber and said
pump outlet to said sump, and a check valve connected from said
sump to said shut off valve oriented to pass hydraulic liquid from
said sump to said second chamber through said shut off valve when
the shut off valve is open and when said piston is moving in a
direction to increase the volume of said second cylinder.
4. A trimming and tilting system for a boat outboard power leg
including a fixed mounting member and a leg support member
connected thereto by means establishing a horizontal tilt axis for
the leg, said system being of the type comprising an extensible
cylinder and piston assembly connected between said members
spanning said axis, a hydraulic liquid sump and a pump connected to
said means for supplying hydraulic liquid under pressure, said
system being characterized in said assembly including a rod
connected to said piston and extending through one end of said
cylinder and occupying a substantial volume in said cylinder
between said piston and said end, a pressure relief valve, a
reverse lock valve, respective conduits connecting said relief
valve to said one and the other ends of said cylinder, said relief
valve being oriented to pass liquid under pressure from said one to
the other of said ends, said lock valve being connected in one of
said conduits and having an open position to permit flow of liquid
through said relief valve and a closed position to prevent such
flow, a check valve connected between said sump and said one end of
said cylinder and oriented to pass liquid from said sump to said
one end and to prevent passage of liquid from said one end into
said sump, manually operable valve means, respective conduit
connections from said valve means to said sump, to said other end
and to said pump, said valve means having a first position opening
said connection from said other end to said pump connection whereby
said pump supplies liquid under pressure into said other end, a
second position sealing said other end connection, and a third
position opening said other end connection into said sump
connection.
5. In a boat drive unit including an outboard leg comprising an
upper housing portion and a steerable lower propeller housing
portion rotatably mounted on said upper portion for rotation on a
generally upright steering axis, hydraulic cylinder means, unitary
piston means in said cylinder means, said cylinder means having
closed ends and said piston means being double acting therein, said
cylinder means and piston means being operatively connected between
said housing portions for steering movement of said lower portion
on said axis in response to movement of said piston means with
respect to said cylinder means, said piston means being provided
with a port normally closed by a wall portion of said cylinder
means and opened upon maximum movement of the piston means
outwardly of one end chamber of said cylinder means, and conduit
means in said piston means extending from said port and connecting
said one end chamber into the other end chamber of said cylinder
means when said port is open, a liquid sump, a hydraulic pump
connected to said sump, and valve means connected to said pump and
to said sump for selectively supplying liquid under pressure from
said pump into said one and said other end chambers of said
cylinder means and for concurrently connecting the respectively
opposite end chamber into said sump.
6. The combination according to claim 5 wherein said valve means
comprises a pair of relatively movable members provided with
registering ports and liquid conduits, said members having a
neutral first relative position in which said source is connected
to said sump and said chambers are sealed off, a port steering
second relative position in which said members are displaced in one
direction from said neutral relative position and in which said one
end chamber is connected to said source and said other end chamber
is connected to said sump, and a starboard steering third relative
position in which said members are displaced in the respectively
opposite direction from said neutral relative position and in which
said other end chamber is conndcted to said source and said one end
chamber is connected to said sump, manually operative means for
displacing one of said members from said neutral position
selectively in said directions, and means operated by liquid flow
through said valve means to move the other of said members in a
follow-up direction in response to displacement of said members
from said neutral position.
7. The combination according to claim 5 wherein said conduit means
is provided with a check valve oriented to block liquid flow from
said other end chamber into said one end chamber.
8. The combination according to claim 5 wherein said valve means
comprises a pair of relatively movable valve members for
cooperatively controlling the flow to and from said end chambers
and having a neutral position, one of said members being manually
movable, and means responsive to said flow for moving said other
member in a follow-up direction.
Description
It is an object of the invention to provide improved hydraulic
steering and tilting and trimming arrangements for a tiltable and
steerable outboard drive unit for a boat. More specific objects are
to provide a hydraulic system including a single source of pressure
fluid for power steering and power tilting and trimming of an
outboard boat drive, and to provide self or automatic bleeding of
entrapped air in such system.
Further specific objects of the inventor are to provide an improved
hydraulic tilting, trimming and damping cylinder system for a boat
drive unit; to provide effective compatibility between hydraulic
power steering and power trimming and tilting systems, or
sub-systems, for an outboard drive leg for a boat; and to provide
in a hydraulic tilting and trimming system for an outboard drive
leg improved controls for adjusting or setting and for maintaining
the trim position of the leg, for rapidly tilting the leg, for
returning the leg from tilted or rearwardly trimmed position to a
forward position of minimum tilt, for locking the leg against
tilting while the propeller is operated in reverse, for releasing
the leg for rearward tilting upon striking a floating or submerged
object and for damping the movement of the leg during such tilting
and for controlling its return movement from tilted position,
together with improved check and pressure relief valve arrangements
for minimizing the occurrence of excess hydraulic pressures in the
hydraulic system and other effects which might cause damage to the
leg or hydraulic system or related components of the drive.
The invention described and claimed in this application is shown as
applied to an inboard-outboard drive arrangement as described in my
co-pending application Ser. No. 907, filed Jan. 6, 1970, entitled
Boat Drive Arrangement and assigned to the assignee hereof.
Reference is made to that application for a further description of
details common to the applications.
The novel features which are believed to be characteristic of this
invention are set forth with particularity in the appended claims.
The invention itself, however, both as to its organization and
method of operation, together with further objects and advantages
thereof, may best be understood by reference to the following
description taken in connection with the accompanying drawings, in
which:
FIG. 1 is a sectional side elevational view of a boat drive
embodying certain components of the hydraulic system according to
the invention;
FIG. 2 is a sectional side elevation of a tilting and trimming
cylinder assembly according to the invention, shown together with
representations partly broken away and in section of portions of
the outboard leg and the mounting means therefore;
FIG. 3 is a sectional view on an enlarged scale of portions of the
cylinder assembly taken along line 3--3 of FIG. 2;
FIG. 4 is a sectional view on an enlarged scale taken along line
4--4 of FIG. 1;
FIG. 5 is a sectional view taken along line 5--5 of FIG. 4; and
FIG. 6 is a schematic diagram of the hydraulic system according to
the invention.
As seen in FIG. 1, the drive includes an inboard engine 1 provided
with a forward, neutral and reverse transmission operated by a
lever 25 controlled by a suitable linkage 26 from the usual
operation station in the boat 2. Controls for the steering and trim
and tilt arrangements are also preferably operable from such
station, the trim and tilt cylinder 18 being provided with a
reverse lock valve having an operating lever 20 coupled by a
linkage 19 to the lever 25 whereby the reverse lock valve is moved
into a lock position simultaneously as the transmission is shifted
into reverse.
The upper portion 13 of tiltable and steerable outboard leg or
housing 12 is mounted to boat transom 3 for trim and tilt movement
on a horizontal transverse tilt axis T on arms 9 (seen in FIG. 2)
supportedly attached to the boat by means including a supporting
bracket or shell 5, all as further described in my said copending
application. Tilt cylinder 18 is pivotally mounted to bracket 5 by
means of a cylindrical journal boss 110 extending from the cylinder
and pivoted in a bearing block 111 integral with the bracket 5.
Bumper 24 limits the forward tilt position of housing portion 13
with respect to bracket 5. Lower portion 14 of leg 12 constitutes a
steerable propeller housing which mounts propeller 15. The
propeller shaft 58 is driven by gears 57 and 62 from downwardly and
forwardly extending driven shaft 42, and this shaft is, in turn
driven by gears 39 and 40 from countershaft 32 mounted in the upper
housing portion. Engine drive shaft 27 is connected through double
universal joint 30, 31 to countershaft 32.
Upwardly extending neck 47 of lower housing portion 14 is rotatably
supported from the upper housing portion by means of pin bearing 51
and ball bearing 52 on a steering axis coaxial with the driven
shaft 42. Shaft 42 is supported in bearing 43 in the upper housing
and in bearings 56 and 45 in the lower housing. The upper housing
includes a chamber 77 forming a cavity 78 in which a steering rack
member 55 and cooperating gear teeth 54 of the neck are disposed.
The chamber is oil filled and has communication through bearing 52
into the oil filled interior of propeller housing portion 14. Oil
seal 53 between circular edge portions of the upper and lower
housing portions prevents escape of oil. The oil filling the
chamber and the interior of the lower housing is a part of the
hydraulic fluid supply for the hydraulic steering and trimming and
tilting system. The oil, being under pressure, also supplies
lubrication to gears 39 and 40 and to the bearings 43, 44, and 51,
as well as to the bearings for countershaft 32 in the upper portion
of the upper housing. A suitable oil seal 112 is provided around
shaft 32 at its emergence from the upper housing.
It is preferred for properly balanced operation that two identical
trimming and tilting cylinder assemblies 18 be employed, connected
in parallel and disposed one on each side of the centerline of the
outboard leg. Details of a cylinder assembly 18 are shown in FIG.
2. As there shown, piston 115 is disposed in a thin walled
operating cylinder liner 116 which is, in turn, disposed within a
relatively heavier casing cylinder 117 which forms end walls for
the operating cylinder and from which the mounting bosses extend
outwardly. The piston rod 118 extends outwardly through outer end
wall 119 of the casing and is slideably sealed therethrough by
packing 120. The outer end 121 of rod 118 is pivotally attached by
means of a pin 122 to an integral portion 123 of upper housing
portion 13, pin 122 being offset below tilt axis T established by
the pivot pin 10 which mounts the upper housing portion to the
boat. The cylinder assembly 18 is thus seen to span the tilt axis
and, upon extension, to cause tilting, or rearward movement, of the
outboard by an axis T.
As shown in FIG. 2, the diameter of piston rod 118 is substantial
with respect to the internal diameter of liner 116, being
preferably not less than about one-third and not more than about
three-quarters of such diameter.
An oil passageway 124 communicates with the interior of liner 116
adjacent end 119 and extends outwardly of the liner within casing
117 to a valve-containing inner end assembly 125 for the cylinder.
The interior of the liner 116 is connected into the inner end
assembly through a passageway 126. A heavily spring loaded relief
valve 127 is disposed in assembly 125 and connects passageway or
conduit 124, upon the occurrence of excessive pressure therein,
into conduit 126. Thus, while valve 127 is normally closed, if the
cylinder assembly is forced to extend, as when the outboard leg
strikes an object which forces it to tilt, hydraulic fluid may flow
from conduit 124 through conduit 126 into the inner end chamber 200
of the cylinder liner. As piston 115 moves in a outward direction,
a greater volume of liquid must enter behind the piston than is
displaced ahead of it. Conduit 126 continues around ball 128 of
valve 127 into conduit 129 and communicates therethrough with
chamber 130 of pressure relief valve 131. The movable valve member
132 of valve 131 is more lightly loaded than ball 128 of valve 127
and member 132 raises to admit the additionally required liquid
into valve chamber 130 and thence into conduit 126 from conduit
133. Conduit 133 connects with passageway 134 in the plug 141 of
reverse lock valve 135 when this valve is open. As seen in FIG. 3,
passageway 134 is connected through a check valve 136 to a
hydraulic fluid connection 137 which, in turn, as later described,
is connected to an oil sump, whereby, during normal forward
operation with the reverse lock valve open, if the drive leg kicks
up, hydraulic fluid from the oil sump passes through check valve
136, passageways 134 and 133, past valve member 132 into chamber
130, and through connecting conduits 129 and 126 into the inner end
chamber 200 of the cylinder. At the same time, fluid is also
passing out of the outer end of the cylinder through conduit 124
into passageway 134 and thence into the inner end of the
cylinder.
The fluid connections 138 and 139 are provided into chamber 130,
one of which, i.e. 139, is provided with a pressure fluid conduit
as later described and the other 138 interconnects the chambers 130
of the identical parallel connected cylinders of the drive
assembly. Fluid connection 140, in communication with conduit 124,
is similarly provided to interconnect and provide free
communication between the outer interior portions of the parallel
connected cylinder assemblies. (The parallel connected cylinder
assemblies are shown at 18 and 18' in FIG. 6).
The plug 141 of reverse lock valve 135 includes a passageway 142
which provides communication between conduit 124 and check valve
136 whether the valve is in open position connecting passageway 134
to conduit 133 or in closed position with the passageway 134 closed
off from conduit 133. Plug 141 is provided with a suitable
operating arm or lever 20.
The spring load on relief valve 131 is sufficient to prevent the
leg from tilting or "floating" up when, during forward propulsion,
the throttle is abruptly moved to idle position or the gears are
shifted into neutral. If the leg strikes an obstacle or is
otherwise forced to tilt by some externally applied force, valve
131 opens but provides a damping force resisting such tilting.
Should the reverse lock valve be closed while the boat is moving
forwardly and if a floating object is then encountered, the more
heavily loaded relief valve 127 will open to prevent destructive
pressures in the hydraulic system or damage to the leg or
mechanical parts of the drive unit.
Normally, the reverse lock valve is closed only when the gears are
in reverse drive position. During reverse drive, the leg is held
against tilting movement by the heavy spring load on valve ball
128. The lighter spring loading of valve 131 is insufficient to
hold the leg against tilting when the propeller is being driven
with substantial power in reverse.
It will be seen in FIG. 2 that a flexible diaphragm or boot 143
seals to the mounting shell 5 outwardly around cylinder 18 to
prevent the entrance of water into the boat.
The steering mechanism disposed in the outboard leg is best shown
in FIGS. 4 and 5. As seen therein, the upstanding neck member 47,
which is rigidly attached to lower housing 14, is provided
exteriorly throughout somewhat less than half of its periphery with
teeth 54 meshing with teeth 63 of rack member 55. The rack member
carries a piston at each end, piston 64 being disposed in a
cylinder 65 and piston 66 being disposed in a cylinder 67. The
cylinders have closed outer ends 68 and 69, respectively, and are
provided with suitable connections to respective hydraulic fluid
lines 22 and 23, whereby the piston and cylinders constitute a
double acting hydraulic cylinder and piston mechanism for moving
the rack member back and forth. Supplying of fluid under pressure
through line 22 causes rotation of portion 14 of the leg about the
axis of shaft 42 in a direction to steer the boat toward a heading
more to port. Supplying of pressure fluid through line 23 results
in alteration of course toward a more starboard heading.
The hydraulic system includes a pump and control elements generally
indicated at 70, the control elements being controlled by a
steering wheel 71 operable to cause the flow of hydraulic fluid
into conduit 22 and to permit return of fluid from conduit 23 in
response to rotation of the wheel in one direction and vice versa
in response to rotation in the opposite direction.
A hydraulic fluid supply or sump generally indicated at 72 is
arranged to supply fluid for the system.
The rack member has motion in each direction limited when one or
the other of pistons 64 and 66 meets the respective cylinder end
wall 68 or 69. The teeth 63 on rack 55 extend through a distance
therealong, and the teeth 54 on neck member 47 extend around the
periphery thereof, sufficiently to accommodate the full extent of
the permitted movement of rack 55. For example the rack may be
arranged to move sufficiently to rotate neck member 47 and lower
housing 14 through a total of approximately 60.degree., 30.degree.
on each side of the dead center or straight ahead steering
position.
In the construction shown, rack member 55 is provided with a
partially threaded reduced generally cylindrical end portion 73
which passes through piston 64 and onto which nut 74 is screwed up
against the piston to hold the piston firmly against shoulder 75 of
the rack member. The end portion 73 is longitudinally bored at 76
into a cross-bored chamber 77 in the rack member. The projection 50
constitutes a fluid containing chamber and housing for the rack and
pinion mechanism and the interior 78 of the housing chamber has
communication through a check valve 79 into the chamber 77 within
the rack member. The check valve 79 may include a light spring 90
seated on pin 91.
The cylinder 65 terminates at an edge 80 which, at cut-away portion
80', exposes a small part of the wall 81 of piston 64 when this
piston is fully extended, that is, with piston 66 stopped by or
very close to end wall 69. A port or passage 82 is drilled into
this portion of the piston wall and communicates with the interior
of cylinder 65 through groove 83 formed around portion 55 of the
rack and through passage 84 drilled from piston face 89 to the
groove.
The arrangement associated with piston 66 will be seen to be
identical to that associated with piston 64 as above described,
including bore 85, port 86, check valve 87 and passage 88 which
correspond, respectively, to bore 76, port 82, check valve 79, and
passage 84.
The above described arrangement provides for self-bleeding and air
scavenging of the steering system. Hydraulic liquid supplied
through line 22 into cylinder 64 causes the piston 64 to move in a
direction outwardly of the cylinder until piston 66 nearly meets
wall 69, whereupon port 82 is exposed to the chamber interior 78
through cut-away portion or notch 80'. Whatever air may be in line
22 and cylinder 65 now passes together with hydraulic fluid into
bore 76, through passages 82 and 84 and through port 82 into the
interior 78 of the housing chamber. The increasing pressure in the
housing chamber opens the lightly loaded check valve 87 and first
any entrapped air, and later hydraulic fluid, pass through the
check valve and bore 85 into cylinder 67 and thence through line
23, finally to return to sump 72. Operation in reverse direction to
supply hydraulic fluid under pressure through line 23 forces piston
66 to move in a direction outwardly of cylinder 67 until port 86 is
uncovered, whereupon hydraulic fluid and any remaining trapped air
pass through channels 88 and 86 into chamber 78 and thence through
check valve 79 and bore 76 into cylinder 65 and through conduit 22
and finally to the sump 72. Fluid is thus circulated back and forth
by turning the steering wheel to and beyond its full steering
effect in one and in the other direction a sufficient number of
times to insure complete bleeding or scavenging of the air from the
system.
In operation, the steering wheel now controls the movement of rack
55 between full starboard and full port steering positions of the
lower housing up to the point at which port 82 or port 86 is
uncovered, whereafter continued movement of the wheel will force a
small flow of hydraulic fluid through the chamber interior 78, as
when the system is being bled. The lower housing may be turned
slightly beyond the full normal port or starboard steering position
by an external force until one or the other of pistons 64 or 66
meets the respective cylinder end wall 68 or 69. Such end play in
the system, with properly proportioned components, will be small,
such as less than one degree of swing of the lower housing. Thus
port 82 should become uncovered only when piston 66 has approached
very close to wall 69 at the maximum steering to port position of
the piston while port 86 should become uncovered at the maximum
steering to starboard position.
The complete hydraulic steering and trimming and tilting system may
be best understood by reference to FIG. 6. Pump 144, driven by the
propulsion engine 1, or by a separate motor or other convenient
means, supplies hydraulic liquid from sump 72 under pressure into
line or conduit 145. The pressure is regulated by a spring loaded
regulator valve 146 which returns excess liquid through oil cooler
147 and filter 148 to the sump. Conduit 149 is connected to receive
pressure liquid through spring loaded check valve 150 from conduit
145 and to supply such liquid into a hydraulic hydrostatic servo
control with internal follow-up shown at 151. The control includes
a cylindrical housing 152, a hollow cylindrical selector valve
spool or sleeve 153 rotatably disposed and fitting closely within
the housing 152, and an inner cylindrical plug 154 rotatably
disposed and fitting closely within sleeve 153. The control further
includes metering follow-up arrangement 155 embodying inner and
outer toothed ring elements 156 and 157, respectively, arranged in
the manner of an orbital gear pump, the outer ring element 157
being fixed and having, for example, six inward teeth and the inner
rotor element 156 having five outward teeth. If oil under pressure
is introduced into the space between the inner and outer elements
through oil channel 158 in partition portion 159 of casing 152, the
oil passes through the metering arrangement and is supplied into
oil channel 160 causing the element 156 to rotate orbitally through
a number of degrees of rotation proportionate to the volume of oil
passing therethrough. Oil passing through metering device 155 from
oil channel 160 to channel 158 will cause rotation of element 157
in the reverse direction.
The inner, orbitally rotatable metering element 156 is coupled to
rotate sleeve 153 by means such as a pin 161, which passes loosely
through an opening 162 in partition 159 and an opening 163 in plug
154, and which fits in a socket 164 in sleeve 153. The fit of pin
161 in opening 162 is such as to allow, for example, 10 or
20.degree. of rotational freedom between the pin and plug 154, but
no appreciable rotational freedom should be allowed between the pin
and sleeve 153.
With sleeve 153 and plug 154 in neutral position, a port 165 in
casing 152 communicates with a channel 166 in sleeve 153, and this
channel communicates into plug channel 167, whereby oil is supplied
from conduit 149 into channel 167. Channel 167, in turn, is in
communication with sleeve channel 168, and this channel
communicates through casing port 169 into the outlet line 170 from
the hydraulic steering sub-system.
It will be seen that sleeve 153 is provided with a circular groove
opposite each of the ports in casing 152. For example, groove 171,
with which oil channel 166 is in communication, is arranged to be
in alignment with port 165 at all times, regardless of the rotative
position of the sleeve in the casing. Similarly, groove 172, which
also extends completely around sleeve 153, and with which oil
channel 168 communicates, is at all times open to port 169.
Channel 167 has a first branch 173 which is connected to port 158
only when plug 154 is rotatably displaced with respect to sleeve
153 in one direction from the neutral position, specifically in the
direction corresponding to steering to port. Channel 167 has a
corresponding second branch 174 which is similarly placed in
communication, through a jumper channel 175 in sleeve 153, a cross
plug channel 176, and sleeve channel 177 with port 160 when plug
154 is rotatably displaced from its neutral position with respect
to sleeve 153 in a direction for steering to starboard.
Port 158, upon steering to starboard is placed in communication
with conduit 23, the connection being completed from this port
through sleeve channel 178, cross plug channel 179, and sleeve
channel 180 with port 181. At the same time, a connection is
established from conduit 22 through its port 182, sleeve channels
183 and 184 and plug jumper channel 185 to outlet line 170. The
connection from port 181 into outlet line 170 is closed off when
the plug is in neutral position and also when it is displaced in
the sleeve in the direction to steer to port because the jumper
channel 186 is in communicating alignment with sleeve channels 187
and 188 only when the plug 154 is displaced in the direction for
steering to starboard.
Upon turning of the steering wheel 71 in a direction to turn plug
154 for steering to port, jumper channel 189 comes into alignment
with branch channel 190, which connects to port 160, and with
sleeve channel 191, which communicates into port 182, thereby to
permit oil to flow from the meter 155 into conduit 22.
It will be noted that circular groove 192 formed in the end of
sleeve 153 is connected to channel 177 and that similar groove 193
is connected to channel 178, whereby port 160 is connected to
channel 177 and port 158 to channel 178 regardless of the rotative
position of the sleeve in casing 152.
Accordingly, with plug 154 in neutral position within sleeve 153,
oil from line 149 passes through channel 166 into channel 167 and
therethrough into channel 168 and into outlet line 170. Branch
channels 173 and 174 are closed off at the sleeve, however,
cross-plug channel 179 is closed off at the sleeve, and jumper
channels 185, 186 and 189 are displaced from their corresponding
sleeve channels, whereby no oil can flow in or out of conduits 22
or 23 or in or out of meter 155.
In order to effectuate steering to port, oil is forced into conduit
22 and is at the same time permitted to flow from conduit 23 into
outlet line 170. This is accomplished by turning the steering wheel
71 so as to rotate plug 154 in sleeve 153 in the direction which
causes branch channel 173 to align with channel 194, thereby to
cause oil under pressure to flow through port 158 into the meter,
and which also causes the port 160 to be opened into channel 191 by
alignment of jumper channel 189 with its associated sleeve channels
161 and 191. At the same time, jumper channel 186 aligns with its
sleeve channels 187 and 188 to open conduit 23 into outlet line
170, but channel 167 remains isolated from channel 176 and is
closed off from channel 168, while channels 179, 183 and 184 remain
closed. The flow of oil measured through the meter causes rotor 156
now to drive sleeve 153 until the neutral relative position between
plug 154 and the sleeve is reestablished. When neutral position is
reached conduits 22 and 23 are closed off, locking the steering
pistons in position, and oil is once again permitted to flow
through channel 167 into the outlet line.
Rotation of the wheel in the opposite direction, to cause a
steering movement toward starboard, results in opening of channel
174 into channel 176 and thence through channel 177 to meter port
160 and opening of channel 178 from port 158 into channels 179 and
180 to conduit 23. At the same time jumper channel 185 connects
conduit 22 into the outlet line 170, while branch 173 remains
closed off from channel 194, channel 190 remains closed off from
channel 191, channel 186 remains closed off from channels 187 and
188, and channel 167 is closed off from channel 168. Oil now flows
from conduit 149 via channels 166, 167, 174, 175, 176 and 177 to
port 160 to enter the meter and to flow therefrom through port 158
into channels 178, 179 and 180 into conduit 23. The flow continues
until the flow in this direction through the meter has caused
sleeve 153 to rotate in the respective follow up direction until
neutral position of the sleeve and plug 154 is once more
established. It will be understood that further steering in the
starboard and port directions is accomplished by turning wheel 71
in one and the other direction, and that for each movement of the
wheel, a corresponding movement of the lower housing portion of the
outboard leg is produced, the extent of which is directly
proportional to the number of degrees of movement of the steering
wheel.
A pair of safety relief valves 195 and 196 are arranged to pass oil
under excessive pressure from the conduits 22 and 23 into the
outlet line 170 to prevent damage to the steering cylinder
assembly.
A three way manually operated selector valve 197 is connected to
outlet line 170 from the steering sub-system. In a valve position
"2," with the valve plug 198 rotated about 30.degree.
counterclockwise from the position "3" in which the valve is shown
in FIG. 6, line 170 is connected to sump return line 199. In order
to originally fill the steering system with oil and to bleed
entrapped air from the steering cylinders and from space 78 (shown
in FIGS. 1 and 4), the valve 197 is preferably set in position "2"
and the steering wheel is turned to port to and beyond the point at
which piston 66 has moved fully into cylinder 67 thereby to cause
oil to flow through port 82 in piston 64. The wheel is then turned
to starboard until the limit position of the pistons is reached and
upon continued starboard steering oil is caused to flow through
port 86 in piston 66. This operation is repeated as may be
necessary to eliminate trapped air.
The elements of the trimming and tilting sub-system as described in
connection with FIGS. 2 and 3 are shown diagrammatically or
schematically in FIG. 6, together with further parts of the
hydraulic system.
There are two identical interconnected trimming and tilting
cylinder assemblies 18 and 18', one for each side of the centerline
of the drive unit. It will be understood that the following
description with respect to assembly 18 is equally applicable to
the parallel connected assembly 18'.
Valve 197 is conveniently located at the helmsman station in the
boat with operating handle 201 readily accessible.
With valve 197 in position "2," the pump up or inner end chamber
200 of cylinder 116 is closed off by the valve plug 198 which seals
conduit 138. A pressure relief valve 202 is, however, connected to
permit bypassing of oil under excessive pressure in conduits 138,
139 into oil return line 199. With valve 197 in position "3,"
pressure oil from line 170, which serves as the oil outlet line
from the hydraulic steering arrangement and the pressure oil supply
line for the tilting and trimming sub-system, is introduced into
conduit 139, preferably through a restriction 203, into the pump up
chamber 200 of cylinder 116, and of course, into the corresponding
chamber of the cylinder assembly 18'. Such supplying of pressure
oil causes extension of piston rod 118 and rearward tilting of the
outboard leg. The resultant movement of piston 115 forces oil into
conduit 124 and thence through normally open reverse lock valve 135
and relief valve 131 into conduits 129 and 138. The volume of oil
flowing into chamber 200 will be greater than the volume flowing
out of the outer end 119 of the cylinder through conduit 124
because of the volume taken up by the piston rod in the
cylinder.
If the leg is prevented from tilting by external force applied
thereto, for example, if the leg has reached its maximum tilt
position, while valve 197 is in position "1," oil will be bypassed
from conduit 139 through pressure relief valve 202 to the sump.
Relief valve 202 is, however, more heavily spring loaded than valve
127, and if the reverse lock valve 135 is closed while valve 197 is
set in position "1" to cause tilting, oil will pass through relief
valve 127, while tilting movement of the leg continues. Now if
further tilting is prevented by an external force on the leg, valve
202 would again open.
When valve 197 is in position "3," as shown in full lines in FIG.
6, the leg is free to move forwardly, toward a position of less
tilt, with oil freely flowing through check valve 136 and into the
cylinder 116 through conduit 124 and with oil flowing from chamber
200 through valve 197 and into sump 72.
Normally valve 197 will remain in position "2," with conduit 139
sealed, except when the trim or tilt position of the leg is being
adjusted. When the engine is shifted into reverse, reverse lock
valve 135 is operated by handle 20 into a position to close conduit
133. As heretofore explained, valve 135 is not designed to close
off the passage from conduit 124 to check valve 136, but check
valve 136 does not permit oil to flow in a direction from cylinder
connection 124 through valve 135 to the sump but only from the sump
to the cylinder. With valve 131 now isolated by closing of valve
135, full reverse power may be applied without opening pressure
relief valve 127.
At any time that the outboard leg is forced to tilt, such as by
striking bottom or a submerged or floating object during forward
movement of the boat, assuming valve 197 to be in position "2," oil
will be forced through relief valve 131, with make-up oil as
required to fill chamber 200 being supplied through check valve 136
from the sump return line 199, which may be supplied from oil
passing from line 170 through valve 197 or from the sump itself. If
the reverse lock valve 135 is in closed position when the leg is
forced to tilt, oil would be forced through relief valve 127,
although it would be unusual for the reverse lock valve to be
closed with the engine in reverse at a time when there would be
sufficient forward motion of the boat to cause such kicking up of
the leg.
Restriction 203 is proportioned to restrict the speed of tilting-up
of the outboard leg when valve 197 is placed in position "1" to
such tilting speed as may be found desirable. The trim of the
outboard leg may be adjusted by moving valve 197 to position "1" to
adjust the leg rearwardly or to position "3" to adjust the leg
forwardly, the valve being then set in position "2" to maintain the
leg in its adjusted trim position.
While the invention has been described with respect to a certain
specific embodiment, it will be appreciated that many modifications
and changes may be made by those skilled in the art without
departing from the spirit of the invention. It is intended,
therefore, by the appended claims to cover all such modifications
and changes as fall within the true spirit and scope of the
invention.
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