U.S. patent application number 09/765117 was filed with the patent office on 2002-07-18 for modulatable power transmission clutch and a marine transmission.
This patent application is currently assigned to Twin Disc, Incorporated. Invention is credited to Bratel, Dean J., Pelligrino, Paul A..
Application Number | 20020094903 09/765117 |
Document ID | / |
Family ID | 25072690 |
Filed Date | 2002-07-18 |
United States Patent
Application |
20020094903 |
Kind Code |
A1 |
Bratel, Dean J. ; et
al. |
July 18, 2002 |
MODULATABLE POWER TRANSMISSION CLUTCH AND A MARINE TRANSMISSION
Abstract
A modulatable power transmission clutch including interleaved
clutch plates and having a central power transmitting shaft
extending axially through the clutch. The clutch includes a fluid
operated movable piston for effecting clutch operation by
compression of the plates. The piston has a smaller piston area and
a larger piston area, the smaller piston area has fluid flow
directed to it a variable fluid pressure whereby the clutch is
modulatable. The larger piston area is adapted to have fluid flow
directed thereto to effect maximum and unmodulatable engagement of
the clutch. A spring loaded normally closed trigger valve controls
fluid flow to the larger piston area in response to fluid pressure
above a predetermined amount at the smaller piston area. The
trigger valve is mounted in the shaft and is normally closed so
that pressure fluid is directed to the smaller piston area at a
variable fluid pressure whereby the clutch is modulatable. When the
valve is open by said fluid pressure over a predetermined amount,
the valve permits fluid flow to the larger piston area to effect
maximum and unmodulatable engagement of the clutch for full clutch
capacity.
Inventors: |
Bratel, Dean J.; (New
Berlin, WI) ; Pelligrino, Paul A.; (Muskego,
WI) |
Correspondence
Address: |
James E. Nilles
NILLES & NILLES, S.C.
Firstar Center, Suite 2000
777 East Wisconsin Avenue
Milwaukee
WI
53202-5345
US
|
Assignee: |
Twin Disc, Incorporated
|
Family ID: |
25072690 |
Appl. No.: |
09/765117 |
Filed: |
January 18, 2001 |
Current U.S.
Class: |
475/116 ;
192/109F; 440/75 |
Current CPC
Class: |
F16D 25/0638 20130101;
F16D 48/02 20130101; B63H 23/30 20130101; F16D 25/14 20130101; F16D
2048/0209 20130101 |
Class at
Publication: |
475/116 ;
192/85.0AA; 192/109.00F; 440/75 |
International
Class: |
F16H 031/00; F16D
025/0638; F16D 013/72 |
Claims
What is claimed is:
1. A modulatable power transmission clutch including interleaved
clutch plates, said clutch having a central power transmitting
shaft extending axially through said clutch mounted thereon, said
clutch including a fluid operated movable piston for effecting
clutch operation by compression of said plates, said piston having
smaller and larger piston areas thereon, the smaller piston area
being adapted to have fluid flow directed thereto at a variable
fluid pressure whereby said clutch is modulatable, the larger
piston area being adapted to have fluid flow directed thereto to
effect maximum and unmodulatable engagement of said clutch; and a
spring loaded normally closed valve for controlling fluid flow to
said larger piston area in response to fluid pressure above a
predetermined amount at said smaller piston area, said valve being
mounted in said shaft and being normally closed whereby pressure
fluid is directed to said smaller piston area at a variable fluid
pressure whereby said clutch is modulatable, and when said valve is
open by said fluid pressure over a predetermined amount permits
fluid flow to said larger piston area to effect maximum and
unmodulatable engagement of said clutch for full clutch
capacity.
2. A modulatable power transmission clutch including interleaved
clutch plates, said clutch comprising a power transmitting shaft
extending axially and centrally through said clutch mounted
thereon, said clutch including a fluid operated movable piston for
effecting clutch operation by compression of said plates, said
piston having two separate fluid application piston areas of
different areas thereon, one smaller of said piston areas being
adapted to have fluid flow directed thereto at a variable fluid
pressure whereby said clutch is modulatable, the other larger of
said piston areas being adapted to have fluid flow directed thereto
to effect maximum and unmodulatable engagement of said clutch; and
valve means for controlling fluid flow to said other larger of said
piston areas in response to fluid pressure at said one smaller of
said piston areas, said valve means being axially slidably mounted
in an axially extending hole in said shaft and spring loaded to a
normally closed position in which pressure fluid is directed to
said one smaller piston area at a variable fluid pressure whereby
said clutch is modulatable, and when said valve means is open it
permits fluid flow to said other larger of said piston area to
effect maximum and unmodulatable engagement of said clutch for full
clutch capacity.
3. A modulatable power transmission clutch including interleaved
clutch plates, said clutch comprising a power transmitting shaft
extending axially and centrally through said clutch mounted
thereon, said clutch including a fluid operated movable piston for
effecting clutch operation by compression of said plates, said
piston having two separate fluid application piston areas of
different areas thereon, one smaller of said piston areas being
adapted to have fluid flow directed thereto at a variable fluid
pressure whereby said clutch is modulatable, the other larger of
said piston areas being adapted to have fluid flow directed thereto
to effect maximum and unmodulatable engagement of said clutch; and
a trigger valve for controlling fluid flow to said other larger of
said piston areas in response to fluid pressure above a certain
valve at said one smaller of said piston areas, a pressure fluid
passage in said shaft for conducting pressure fluid to said smaller
area and to said larger piston area, said trigger valve being
located in said shaft passage and being spring loaded to a normally
closed position in which pressure fluid is directed to said one
smaller piston area at a variable fluid pressure whereby said
clutch is modulatable, said trigger valve when closed acting to
block flow of fluid to said larger area below a predetermined
pressure and when open acting to permit fluid flow above a
predetermined pressure to said larger area of said piston to effect
maximum and unmodulatable engagement of said clutch for full clutch
capacity.
4. A marine transmission for variable speed control of a boat
having a propeller for providing modulatable lower speed in both
forward and reverse direction for maneuvering during docking of
said boat to provide enhanced docking control and boat positioning;
said transmission providing seamless transition from modulation
during which speed can be increased slightly to full clutch
engagement and capacity for driving said propeller; said
transmission including a modulatable power transmission clutch
including interleaved clutch plates, said clutch comprising a power
transmitting shaft extending axially and centrally through said
clutch mounted thereon, said clutch including a fluid operated
movable piston for effecting clutch operation by compression of
said plates, said piston having two separate fluid application
piston areas of different areas thereon, one smaller of said piston
areas being adapted to have fluid flow directed thereto at a
variable fluid pressure whereby said clutch is modulatable for said
docking, the other larger of said piston areas being adapted to
have fluid flow directed thereto to effect maximum and
unmodulatable engagement of said clutch for driving said propeller;
and valve means for controlling fluid flow to said other larger of
said piston areas in response to fluid pressure at said one smaller
of said piston areas, said valve means being axially slidably
mounted in an axially extending hole in said shaft and spring
loaded to a normally closed position in which pressure fluid is
directed to said one smaller piston area at a variable fluid
pressure whereby said clutch is modulatable, and when said valve
means is open it permits fluid flow to said other larger of said
piston area to effect maximum and unmodulatable engagement of said
clutch for full clutch capacity available to said propeller.
5. A power transmission including a forward modulatable power
transmission clutch and a rear modulatable power transmission
clutch, said forward clutch connected in power receiving connection
with a prime mover and in power delivering connection with load to
be driven, said rear clutch being connected in driven engagement
with said forward clutch and engageable with said load to be driven
for driving the latter in a reverse direction, said forward and
rear clutches each including clutch plates, a power transmitting
shaft extending axially and centrally therethrough, said clutch
including a fluid operated movable piston for effecting clutch
operation by compression of said plates, said piston having two
separate fluid application piston areas of different areas thereon,
one smaller of said piston areas being adapted to have fluid flow
directed thereto at a variable fluid pressure whereby said clutch
is modulatable, the other larger of said piston areas being adapted
to have fluid flow directed thereto to effect maximum and
unmodulatable engagement of said clutch; and valve means for
controlling fluid flow to said other larger of said piston areas in
response to fluid pressure above a predetermined amount at said one
smaller of said piston areas, said valve means being axially
slidably mounted in an axially extending hole in said shaft and
spring loaded to a normally closed position in which pressure fluid
is directed to said one smaller piston area at a variable fluid
pressure whereby said clutch is modulatable, and when said valve
means is open it permits fluid flow to said other larger of said
piston area to effect maximum and unmodulatable engagement of said
clutch for full clutch capacity.
6. A power transmission including a forward modulatable power
transmission clutch and a rear modulatable power transmission
clutch, said forward clutch connected in power receiving connection
with a prime mover and in power delivering connection with load to
be driven, said rear clutch being connected in driven engagement
with said forward clutch and engageable with said load to be driven
for driving the latter in a reverse direction, said forward and
rear clutches each including clutch plates, a power transmitting
shaft extending axially and centrally therethrough, each of said
clutches including a fluid operated movable piston for effecting
clutch operation by compression of said plates, said piston having
two separate fluid application piston areas of different areas
thereon, one smaller of said piston areas being adapted to have
fluid flow directed thereto at a variable fluid pressure whereby
said clutch is modulatable, the other larger of said piston areas
being adapted to have fluid flow directed thereto to effect maximum
and unmodulatable engagement of said clutch; and for each of said
forward and rear clutches, a trigger valve for controlling fluid
flow to said other larger of said piston areas in response to fluid
pressure above a certain valve at said one smaller of said piston
areas, a pressure fluid passage in said shaft for conducting
pressure fluid to said smaller area and to said larger piston area,
said trigger valve being located in said shaft passage and being
spring loaded to a normally closed position in which pressure fluid
is directed to said one smaller piston area at a variable fluid
pressure whereby said clutch is modulatable, said trigger valve
when closed acting to block flow of fluid to said larger area below
a predetermined pressure, and when said trigger valve is open
acting to permit fluid flow above a predetermined pressure to said
larger area of said piston to effect maximum and unmodulatable
engagement of said clutch for full clutch capacity.
7. A marine transmission for variable speed control of a boat
having a propeller for providing modulatable lower speed in both
forward and reverse direction for maneuvering during docking of
said boat to provide enhanced docking control and boat positioning;
said transmission providing seamless transition from modulation
during which speed can be increased slightly to full clutch
engagement and capacity for driving said propeller; said
transmission including a forward modulatable power transmission
clutch and a rear modulatable power transmission clutch, said
forward clutch connected in power receiving connection with a prime
mover and in power delivering connection with load to be driven,
said rear clutch being connected in driven engagement with said
forward clutch and engageable with said load to be driven for
driving the latter in a reverse direction, said forward and rear
clutches each including clutch plates, a power transmitting shaft
extending axially and centrally therethrough, said clutches
including a fluid operated movable piston for effecting clutch
operation by compression of said plates, said piston having two
separate fluid application piston areas of different areas thereon,
one smaller of said piston areas being adapted to have fluid flow
directed thereto at a variable fluid pressure whereby said clutch
is modulatable for said docking, the other larger of said piston
areas being adapted to have fluid flow directed thereto to effect
maximum and unmodulatable engagement of said clutch for driving
said propeller; and for each of said forward and rear clutches, a
trigger valve for controlling fluid flow to said other larger of
said piston areas in response to fluid pressure above a certain
valve at said one smaller of said piston areas, a pressure fluid
passage in said shaft for conducting pressure fluid to said smaller
area and to said larger piston area, said trigger valve being
located in said shaft passage and being spring loaded to a normally
closed position in which pressure fluid is directed to said one
smaller piston area at a variable fluid pressure whereby said
clutch is modulatable, said trigger valve when closed acting to
block flow of fluid to said larger area below a predetermined
pressure, and when said trigger valve is open acting to permit
fluid flow above a predetermined pressure to said larger area of
said piston to effect maximum and unmodulatable engagement of said
clutch for full clutch capacity, and an electronic control circuit
for said transmission including a source of pressure fluid, a
proportional valve connected to said source for delivering pressure
fluid to said rear clutch, said source connected to another
proportional valve for delivering pressure fluid to said forward
clutch, said circuit also including a control lever operatively
connected with said proportional valves for selective operation
thereof to effect forward or reverse operation of said boat.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of Use
[0002] This invention relates generally to modulatable power
transmission clutches and, in particular, to those wherein a
fluid-applied spring release piston operates on clutch plates which
are disposed between a rotatable driving member and a rotatable
driven member to effect clutch modulation.
[0003] 2. Description of the Prior Art
[0004] Each of the following U. S. patents has been assigned to an
assignee common with the present application.
[0005] U.S. Pat. No. 4,451,238, issued May 29, 1984 to Arnold,
discloses a multi-clutch transmission with forward and reverse
shafts and gear trains between these shafts, and discusses the
damaging shocks to the propulsion system which sometimes occur
during maneuvering operations.
[0006] U. S. Pat. No. 4,459,873, issued Jul. 17, 1984 to Black,
shows a marine propulsion system and discusses a brake which is
engaged to anchor a portion of the planetary gear system to drive
the propeller in a forward direction, and the brake is disengaged
when the torque converter is driving the propeller shaft in the
reverse direction. This patent discusses prior art transmissions,
which were not always satisfactory because of flutter failure of
the forward drive clutch, when it was required to operate in the
reverse direction for reversing the direction of the boat.
[0007] U. S. Pat. No. 4,836,809, issued Jun. 6, 1989 to Pelligrino,
discloses a marine vessel propulsion system having forward and
reverse clutches in which each clutch can be fully engaged, fully
disengaged, and modulated.
[0008] U. S. Pat. No. 4,186,829, issued Feb. 5, 1980 to Schneider
and Pelligrino, discloses a modulatable power transmission clutch.
This patent discloses a spring biased trigger valve, which is
located radially outwardly of the central power transmission shaft
on which the clutch is mounted.
SUMMARY OF THE PRESENT INVENTION
[0009] The present invention provides a modulatable power
transmission clutch and also a marine transmission system for
variable speed control having dual area clutch pistons. Clutch
capacity is varied by separate fluid areas of the clutch, one area
being smaller than the other. The marine transmission clutch is
modulated by means of the small area of the piston utilizing a
selectively operable control resulting in variable propeller speed.
Pressure fluid is supplied to the small area by controlling a
proportional valve. Modulation of the clutch offers enhanced
docking control and vessel positioning. At a predetermined pressure
level at the source area of the piston, a spring biased trigger
valve allows the flow of pressure fluid to the large area of the
piston whereby the clutch can reach full clutch capacity. The
system offers seamless transition from modulating operation of the
clutch where engine speed can be increased slightly to full
engagement of the clutch.
[0010] The dual area clutch provided by the present invention
provides smooth transition from the initial docking mode and
provides for precise and rapid back and forth changes in speed for
maneuvering in the docking procedure. The valve of the present
invention is located in the central power transmission shaft that
extends through the clutch, is much less complicated than the
valves of the prior art, and is not affected by centrifugal
pressure.
[0011] These and other objects and advantages of the invention will
appear as this disclosure progresses.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a longitudinal cross-sectional view through a
clutch made in accordance with the present invention and also
includes a schematic diagram of the control system therefor;
[0013] FIG. 2 is a longitudinal cross-sectional view through a
transmission of the present invention and includes a showing of
both the forward and reverse clutches, the rear clutch being
rotated around the input shaft from its normal position and into a
plane with the forward clutch for clarity in the drawings;
[0014] FIG. 3 is a transverse, cross-sectional, schematic view on a
reduced scale showing the usual relative positions of the two
clutches and the output shaft as shown in FIG. 2;
[0015] FIGS. 4 and 5 are enlarged fragmentary views of the trigger
valve shown in FIGS. 1 and 2 and shown, respectively, in the closed
and open position;
[0016] FIG. 6 is a graph showing the characteristics of the clutch
wherein the position of the control lever in degrees is plotted
against the engine rpm, the clutch rpm, and the engine/clutch rpm;
and
[0017] FIG. 7 is a side elevational view of a marine craft
utilizing the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0018] As shown in FIG. 1, the present invention relates to a
forward clutch F of the type having interleaved friction plates
some of which are splined respectively to a hollow cylinder housing
10 that is fixed to a power input shaft 11 on which it is mounted
for rotation therewith and driven by engine E (FIG. 2) through
input coupling G splined to shaft 11. The other interleaved plates
are splined to the output gear 12 as is conventional. A spring 14
mounted around shaft 11 and at one end bears against an axially
fixed snap ring 15. The other end of the spring acts against the
clutch piston 17 that is slidable in the chamber 18, to urge the
piston to a clutch disengaged position.
[0019] It will be noted that the annular piston 17 has a smaller
area 20, which defines with the housing 10 and small clutch
actuating chamber 21. The piston 17 also has a larger area 24,
which with the housing defines a large clutch actuating chamber
25.
[0020] A fluid passage 30 is rifle drilled in shaft 11 for
conducting pressure fluid from a proportional valve 70, and through
a cross port 31 to the small piston area 20.
[0021] A spring loaded trigger valve 35, shown on an enlarged scale
in FIGS. 4 and 5, is located in passage 30 and the head 35 of the
valve acts under the action of the spring 36 and against valve seat
37 formed in the passage 30. Fluid passage 40 places fluid passage
30 in communication with the large area of the chamber 25 when
pressure fluid in passage 30 is great enough to compress spring
36.
[0022] As shown in FIG. 2, the forward clutch F and reverse clutch
R are in constant mesh with one another through their annular
external gears 50 and 51 formed around their housing. Gear 60 is
fixed to the propeller shaft 61, which is suitably journaled in the
gear transmission case 64. Shaft 62 of the reverse clutch R, shaft
11 of the forward shaft and the propeller shaft 61 are all suitably
journaled in the gear casing 64 on conventional antifriction
tapered roller bearings as shown. The forward clutch F shown and
described in FIG. 1 is the same as the reverse clutch R and further
description of the reverse clutch is deemed to be neither necessary
nor desirable.
[0023] As shown in schematic FIG. 3, the gears 12, 52 and 60 are in
constant mesh. The reverse clutch R is used to reverse output
direction.
[0024] Referring to the schematic diagram in the control system in
FIG. 1, a control lever L is utilized, through an electronic
controller EC, to select operation of the either the forward or the
reverse clutch. When the lever L is moved to the right, it causes
actuation of the forward clutch. Conversely, when the lever L is
moved to the left, it causes actuation of the reverse clutch. It
will be noted that the lever has a troll position in either forward
or reverse. When the lever is moved from neutral to the troll
position, the clutch operates in a troll mode. Then further
movement of the lever acts to cause increase in engine speed. As
shown in FIG. 6, when the lever reaches the 40.degree. mark,
continued movement of the lever increases the engine/clutch rpm as
shown. It also increases the clutch pressure as shown on the
right-hand side of the graph. The proportional valve 70 is provided
for the forward clutch F and a proportional valve 72 is provided
for the reverse clutch R. Proportional valves 70 and 72 are similar
and operate to draw pressure fluid from the source 73 and direct it
to either clutch F or clutch R, respectively. Pressure fluid is
also directed to a main regulator 75 (FIG. 1) and lubrication
passage 76 for lubricating the drive plates and bearings of the
clutches via the rifle drilling 77 in the shaft and in the known
manner.
[0025] Generally, the electronic control (EC) is
microprocessor-based and sends a pulse width modulated (PWM) signal
to control the proportional valves 70 and 72 for each clutch. The
level of the PWM signal sent to the valves is directly related to
the position of lever L. By utilizing the small area 20 of the
clutch, a wide pressure differential is realized to modulate the
clutch. Thus, the electronic control (EC) is programmable to allow
the engine speed to match the propeller horsepower selected for
clutch synchronization.
Recapitulation
[0026] The present invention provides for a marine transmission
system for variable speed control comprising an electronic control
system and dual area clutch pistons. Clutch capacity is varied by
separate fluid areas to the clutch, one area being smaller than the
other. The marine transmission clutch is modulated via the small
area of the piston utilizing a selectively operable control
allowing variable propeller speed. Fluid is supplied to the small
area by controlling a proportional valve via the control.
Modulation offers enhanced docking control and vessel positioning.
At a predetermined level, a spring biased trigger valve controls
the fluid to the large area of the piston to reach full clutch
capacity.
[0027] The initial actuation or modulation of the clutch is
utilized, for example, for marine boats for docking and vessel
positioning. The fluid pump P (FIG. 1) which supplies fluid to the
proportional valves 70 or 72 provides fluid pressure. The lever L
in the quadrant shown in FIG. 1, which is movable from a neutral
position to a detent position and then to forward position,
actuates the valves. Similarly, the quadrant can be swung in the
opposite direction for reverse of the transmission when fluid is
directed to the other proportional valve 72 for reverse operation
of the transmission. In either direction, pressure fluid is first
admitted to the small area 20 behind the piston 17 and after it
reaches a certain pressure, the piston is urged to open against the
pressure of its spring 14 and permit pressure fluid to flow to the
large area behind the piston. The arrangement provides for a
variable speed control and clutch capacity is varied by separate
fluid areas of the clutch, one area being smaller than the other
area. The transmission clutches are modulated via the small area of
the piston utilizing a selectively operable control allowing
variable output speed.
[0028] Modulation of the clutch offers docking control and vessel
positioning. Then at a predetermined pressure level, the spring
biased trigger valve controls the flow of fluid to the large area
of the piston to thereby cause it to reach full clutch capacity.
This system provides seamless transition from modulation to full
engagement. During modulation, engine speed can be increased
slightly. After modulation the engine throttle is controlled.
[0029] By locating the trigger valve in the center shaft of the
clutch, it is not influenced by centrifugal speed of the clutch.
Furthermore, the present trigger valve in its operation is much
simpler than the prior art triggering valve. This provides for
immediate response during modulation and the engine speed can be
increased slightly and accurately in either direction to provide
precise and rapid back and forth changes in speed for maneuvering,
for example, of the boat during the docking procedure.
* * * * *