HK1061267A - Modulatable power transmission clutch and a marine tran - Google Patents

Description

Adjustable power transmission clutch and marine transmission

Technical Field

The present invention relates generally to adjustable power transmission clutches, and more particularly to such clutches wherein a fluid-acted spring-release piston operates clutch plates disposed between a rotatable driving member and a rotatable driven member to effect clutch adjustment.

Background

Each of the following U.S. patents is assigned to the assignee of the present application.

US patent 4451238 issued on Arnold on 29.5.1984 discloses a multi-clutch transmission with a forward shaft and a reverse shaft and a gear train between these shafts, and discusses vibrations that are sometimes generated during manoeuvring operations and that are detrimental to the propulsion system.

US4459873 issued to Black at 17.7.1984 discloses a marine propulsion system and discusses a brake for securing a portion of a planetary gear system to drive a propeller in a forward direction and disengaging the brake when a torque converter drives the propeller shaft in a reverse direction. This patent discusses a prior art transmission that is not always satisfactory due to a flutter failure of the forward drive clutch when operation in the reverse direction is required to reverse the boat.

U.S. Pat. No. 4,483,09 to Pelligrino, 6.1989, discloses a marine propulsion system having forward and reverse clutches, each of which can be fully engaged, fully disengaged and adjusted.

Adjustable power transmission clutches are disclosed in US patent 4186829 issued to Schneider on 2/5 1980. This patent discloses a spring biased trigger valve located radially outwardly of a central power transmission shaft to which the clutch is mounted.

Disclosure of Invention

The invention provides an adjustable power transmission clutch and a marine transmission system with a dual-zone clutch piston for variable speed control. Clutch capacity is varied by dividing the fluid zones of the clutch and making one zone smaller than the other. The marine transmission clutch is adjustable by means of a small area of the piston with selectively operable control producing variable propeller speed. The pressurized fluid is directed to a smaller area by controlling the proportional valve. Adjustment of the clutch enhances docking control and vessel positioning. At a predetermined pressure level in the source region of the piston, the spring biases the trigger valve to direct pressurized fluid to a larger area of the piston, thereby enabling the clutch to reach full clutch capacity. The system enables the clutch to enter a fully closed state by slightly increasing the rotation speed of the engine, thereby realizing stepless conversion from the adjustment operation of the clutch to the capacity operation of the full clutch.

The dual zone clutch of the present invention provides a smooth transition from the initial docking mode and provides an accurate and rapid speed change back and forth for maneuvering during docking. The valve of the present invention is located in a central power transmission shaft extending through the clutch, and is of simpler construction than prior art valves and is not subject to centrifugal pressure.

The above and other objects and advantages of the present invention will be understood from the following disclosure.

Drawings

FIG. 1 is a longitudinal cross-sectional view of the clutch of the present invention and a schematic of its control system;

FIG. 2 is a longitudinal cross-sectional view of the transmission of the present invention showing the forward clutch and the reverse clutch for clarity, the reverse clutch rotating about the input shaft into a plane with the forward clutch from its normal position;

FIG. 3 is a reduced transverse cross-sectional view illustrating the relative positions of the two clutches and the output shaft shown in FIG. 2;

FIGS. 4 and 5 are enlarged views of the trigger valve of FIGS. 1 and 2 in the closed and open positions, respectively;

FIG. 6 is a clutch characteristic graph plotting angular position of the lever versus engine revolutions per minute (rpm), clutch revolutions per minute, and engine/clutch revolutions per minute; and

figure 7 is a side view of a water vessel using the present invention.

Detailed Description

As shown in fig. 1, the present invention relates to a forward clutch F of the type having embedded friction plates, some of which are respectively engaged with a hollow cylindrical housing 10 by splines, the hollow cylindrical housing 10 being fixed to a power input shaft 11, the hollow cylindrical housing 10 being mounted on the power input shaft 11 so as to rotate therewith and being driven by an engine E via an input coupling G (see fig. 2), the input coupling G being engaged with the shaft 11 by splines. The other insert plate is splined to the output gear 12 in the usual manner. The spring 14 is mounted around the shaft 11 with one end abutting against an axially fixed snap ring 15. The other end of the spring bears against a clutch piston 17, which clutch piston 17 is slidable in a chamber 18 in order to push the piston into a clutch disengaged position.

It is noted that the annular circular piston 17 has a smaller area 20 which forms a small clutch actuation chamber 21 with the housing 10. The piston 17 also has a larger area 24 which forms with the housing a large clutch actuation chamber 25.

The flow passage 30 is a bore drilled in the shaft 11 with a gun drill for directing pressurized fluid from the proportional valve 70 through the transverse port 31 to the small piston area 20.

As shown in the enlarged views of fig. 4 and 5, a spring-loaded trigger valve 35 is disposed within the passage 30, the valve head 35 acting under the action of a spring 36 and bearing against a valve seat 37 formed within the passage 30. The flow passage 40 communicates the flow passage 30 with a large area of the chamber 25 when the pressure of the pressurized fluid in the passage 30 is great enough to compress the spring 36.

As shown in fig. 2, the forward clutch F and the reverse clutch R are continuously engaged with each other by ring-shaped external gears 50 and 51 formed around the clutch housing. The gear 60 is fixed to a propeller shaft 61, the propeller shaft 61 being adapted to be journalled in a gear box 64. The shaft 62 of the reverse clutch R, the forward shaft 11 and the propeller shaft 61 are all adapted to be journaled in conventional anti-friction tapered roller bearings as shown in the gear box 64. The forward clutch F is shown and described in FIG. 1 as being the same as the reverse clutch R, and therefore further description of the reverse clutch is not necessary or required.

As shown in fig. 3, gears 12, 52 and 60 are in constant mesh. The reverse clutch R is used to reverse the output direction.

Referring to the schematic diagram of the control system in fig. 1, the operation of the forward clutch or the reverse clutch is selected by the electronic controller EC using the lever L. When the lever L is moved to the right, the forward clutch is activated. Conversely, when the lever L is moved to the left, the reverse clutch is activated. It is noted that the lever has a rotational position in forward or reverse. The clutch operates in a rotational manner when the lever is moved from the neutral position to the rotational position. Further movement of the joystick increases the engine speed. As shown in fig. 6, the continued movement of the lever increases the engine/clutch rpm when the lever reaches the 40 mark. But also increases clutch pressure as shown on the right side of the graph. A proportional valve 70 is provided for the forward clutch F and a proportional valve 72 is provided for the reverse clutch R. The proportional valves 70 and 72 are identical and operate to draw pressurized fluid from a source and to either clutch F or clutch R, respectively. The pressurized fluid also flows to a main regulator 75 (see fig. 1) and a lubrication passage 76 for lubricating the drive plate and the clutch bearing in a known manner through a gun drill bore 77 in the shaft.

Typically, an Electronic Controller (EC) is microprocessor based and sends Pulse Width Modulation (PWM) signals to control the proportional valves 70 and 72 of each clutch. The PWM signal sent to the valve is directly related to the position of the lever L. The clutch is adjusted by creating a large pressure differential with a small area 20 of the clutch. Thus, the Electronic Controller (EC) is programmable to match the engine speed to the propeller horsepower selected for clutch synchronization.

Brief description of the drawings

The invention provides a marine transmission system for performing various speed control, which comprises an electronic control system and a dual-area clutch piston. Clutch capacity is varied by dividing the fluid zones of the clutch so that one zone is smaller than the other. The marine transmission clutch is adjusted through a small area of the piston by a selectively operable controller that achieves variable propeller speed. The proportional valve is controlled by a controller to deliver fluid to a small area. This adjustment enhances docking control and vessel positioning. The spring biases the trigger valve to control fluid flow to a large area of the piston at a predetermined level to achieve full clutch capacity.

Initial actuation or adjustment of the clutch is used to dock and position the boat. A fluid pump P (see fig. 1) that pumps fluid to the proportional valve 70 or 72 creates fluid pressure. The lever L in the sector tiller shown in fig. 1 can be moved from a neutral position to a braking position and then to a forward position, whereby the valve is activated. Similarly, when fluid flows to the other proportional valve 72 which effects reverse operation of the transmission, the sector tiller can be swung in the opposite direction to reverse the transmission. In the other direction, the pressurized fluid first flows to a small area 20 behind the piston 17 and, after it has reached a certain pressure, pushes the piston open against the pressure of the spring 14, causing the pressurized fluid to flow to a large area behind the piston. This configuration provides variable speed control and changes clutch capacity by dividing the fluid zones of the clutch so that one zone is smaller than the other. The transmission clutch is adjusted by a small area of the piston using a selectively operable controller that achieves a variable output speed.

Adjustment of the clutch provides docking control and vessel positioning. Thus, at a predetermined pressure level, the spring biased start valve controls the flow of fluid to a large area of the piston, thereby bringing it to full clutch capacity. The system provides a stepless transition from regulation to full engagement. In the regulation, the engine speed may be increased in a minute amount. After the adjustment, the engine throttle is controlled.

The starting valve is not influenced by the centrifugal speed of the clutch by being arranged on the central shaft of the clutch. Furthermore, the starting valve of the invention in its operating state is simpler than prior art starting valves. This structure is provided for immediate response in adjustment and the engine speed is increased in minute amounts in either direction precisely for precise and rapid speed change back and forth to maneuver the boat during docking.

Claims (7)

1. A modulatable power transmission clutch including interleaved clutch plates, said clutch having a central power transmission shaft extending axially through said clutch mounted thereon, said clutch including a fluid operated movable piston for effecting clutch operation by compressing said clutch plates, said piston having smaller and larger piston areas thereon, the smaller piston area being adapted to have fluid flow thereto at a variable fluid pressure whereby said clutch is modulatable, the larger piston area being adapted to have fluid flow thereto to effect maximum and non-modulatable engagement of said clutch;

and a spring-loaded normally closed valve for controlling fluid flow to said larger area in response to a predetermined amount of fluid pressure above said smaller piston area, said valve being mounted within said shaft and being normally closed thereby to render said clutch adjustable, and when said fluid pressure exceeds a predetermined amount to cause said valve to open, fluid flow to said larger area to effect maximum and non-adjustable engagement of said clutch to full clutch capacity.

2. A modulatable power transmission clutch including interleaved clutch plates, said clutch including a power transmission shaft extending axially through said clutch mounted thereon, said clutch including a fluid operated movable piston for effecting clutch operation by compressing said clutch plates, said piston having two separate fluid apply piston areas of different areas thereon, the smaller piston area of said piston being adapted to have fluid flow thereto at a variable fluid pressure whereby said clutch is modulatable, the larger said piston area being adapted to have fluid flow thereto for maximum and non-modulatable engagement of said clutch;

and valve means for controlling fluid flow to said larger piston area in response to fluid pressure in said smaller piston area, said valve means being axially slidably mounted in an axially extending bore in said shaft and being spring biased to a normally closed position wherein pressurized fluid flows to said smaller area at a variable fluid pressure thereby to cause said clutch to be modulated and when said valve means is open, fluid flow to said larger piston area to effect maximum and non-modulated engagement of said clutch to full clutch capacity.

3. A modulatable power transmission clutch including interleaved clutch plates, said clutch having a power transmission 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 clutch plates, said piston having two separate fluid-applied piston regions of different areas thereon, the smaller of said piston regions being adapted to have fluid flow thereto at a variable fluid pressure whereby said clutch is modulatable, the larger of said piston regions being adapted to have fluid flow thereto to effect maximum and non-modulatable engagement of said clutch;

and an activation valve for controlling fluid flow to the larger area in response to a predetermined amount of fluid pressure above the smaller piston area; a pressurized fluid flow passage in said shaft for pressurized fluid to said smaller area and to said larger piston area; the trigger valve is disposed within the shaft passage and is spring-biased to a normally closed position wherein pressurized fluid flows to the smaller piston area at variable fluid pressure, thereby modulating the clutch, closes below a predetermined pressure, blocking fluid flow to the larger area, and opens to allow fluid flow above the predetermined pressure to the larger area of the piston to achieve maximum and non-modulating engagement of the clutch to full clutch capacity.

4. A marine transmission for variable speed control of a vessel having a propeller for providing adjustable low speed in forward and reverse directions for maneuvering when the vessel is docked, thereby enhancing docking control and vessel positioning;

the transmission is made continuously variable by a regulation in which the speed is increased in a minute manner in order to reach full clutch engagement and full clutch capacity driving the propeller;

said transmission including an adjustable power transmission clutch including nested clutch plates, said clutch having a power transmission 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 clutch plates, said piston having two separate fluid-acting piston regions thereon of different areas, the smaller of said piston regions being adapted to have fluid flow thereto at variable fluid pressure whereby said clutch is adjustable for said docking, the larger of said piston regions being adapted to have fluid flow thereto for maximum and non-adjustable engagement of said clutch for driving said propeller;

and valve means for controlling fluid flow to said larger region in response to fluid pressure in said smaller piston region, said valve means being axially slidably mounted in an axially extending bore in said shaft and spring biased to a normally closed position in which pressurized fluid flows to said smaller piston region at a variable fluid pressure thereby to render said clutch adjustable and when said valve means is open to allow fluid flow to said larger piston region to effect maximum and non-adjustable engagement of said clutch to full clutch capacity driving said propeller.

5. A power transmission device comprises a forward adjustable power transmission clutch and a reverse adjustable power transmission clutch, wherein the forward clutch is in power receiving connection with a prime motor and in power output connection with a load to be driven,

the reverse clutch being in driven engagement with the forward clutch and being engageable with the load to be driven to drive the load in a reverse direction,

said forward and reverse clutches each comprising clutch plates with a power transmission shaft extending axially therealong and passing centrally therethrough, said clutch including a fluid-operated movable piston for effecting clutch operation by compression of said clutch plates, said piston having two separate fluid-apply piston regions of different areas thereon, the smaller of said piston regions being adapted to have fluid flow thereto at variable fluid pressure whereby said clutch is adjustable, the larger of said piston regions being adapted to have fluid flow thereto for maximum and non-adjustable engagement of said clutch;

and valve means for controlling fluid flow to said larger region in response to a predetermined amount of fluid pressure above said smaller piston region, said valve means being slidably mounted axially within an axially extending bore in said shaft and being spring biased to a normally closed position wherein pressurized fluid flows to said smaller piston region at a variable fluid pressure thereby modulating said clutch and when said valve means is open, fluid flows to said larger piston region to effect maximum and non-modulating engagement of said clutch to full clutch capacity.

6. A power transmission device comprises a forward adjustable power transmission clutch and a reverse adjustable power transmission clutch, wherein the forward clutch is in power receiving connection with a prime motor and in power output connection with a load to be driven,

the reverse clutch being in driven engagement with the forward clutch and being engageable with the load to be driven to drive the load in a reverse direction,

said forward and reverse clutches each comprising clutch plates with a power transmission shaft extending axially therealong and passing centrally therethrough, each said clutch including a fluid-operated movable piston for effecting clutch operation by compression of said clutch plates, said piston having two separate fluid-apply piston regions of different areas thereon, the smaller of said piston regions being adapted to have fluid flow thereto at a variable fluid pressure whereby to render said clutch adjustable, the larger of said piston regions being adapted to have fluid flow thereto for maximum and non-adjustable engagement of said clutch;

and for each of said forward and reverse clutches

An activation valve for controlling fluid flow to the larger piston area in response to a predetermined amount of fluid pressure above the smaller piston area; a pressurized fluid flow passage in said shaft for flowing pressurized fluid to said smaller area and said larger piston area; the trigger valve is disposed in the shaft flow passage and is spring biased to a normally closed position wherein pressurized fluid flows at variable fluid pressure to the smaller piston area thereby modulating the clutch, the trigger valve being closed to block fluid flow to the larger area below a predetermined pressure, and the trigger valve being open to allow fluid flow above the predetermined pressure to the larger area of the piston to achieve maximum and non-modulating engagement of the clutch to full clutch capacity.

7. A marine transmission for variable speed control of a vessel having a propeller for providing adjustable low speed in forward and reverse directions for maneuvering when the vessel is docked, thereby enhancing docking control and vessel positioning;

the transmission is made continuously variable by a regulation in which the speed is increased in a minute manner in order to reach full clutch engagement and full clutch capacity driving the propeller;

the transmission device comprises a forward adjustable power transmission clutch and a reverse adjustable power transmission clutch, the forward clutch is in power receiving connection with a prime motor and is in power output connection with a load to be driven,

the reverse clutch being in driven engagement with the forward clutch and being engageable with the load to be carried,

said forward and reverse clutches each comprising clutch plates with a power transmission shaft extending axially therealong and passing centrally therethrough, each said clutch including a fluid-operated movable piston for effecting clutch operation by compression of said clutch plates, said piston having two separate fluid-apply piston regions of different areas thereon, the smaller of said piston regions being adapted to have fluid flow thereto at a variable fluid pressure whereby to render said clutch adjustable, the larger of said piston regions being adapted to have fluid flow thereto for maximum and non-adjustable engagement of said clutch;

and for each of said forward and reverse clutches

An activation valve for controlling fluid flow to the larger piston area in response to a predetermined amount of fluid pressure above the smaller piston area; a pressurized fluid flow passage in said shaft for pressurized fluid to said smaller area and to said larger piston area; said trigger valve being disposed in said shaft flow passage and spring biased to a normally closed position wherein pressurized fluid flows to said smaller piston area at variable fluid pressure thereby modulating said clutch, said trigger valve being closed to block said fluid flow to said larger area below a predetermined pressure, said trigger valve being open to allow fluid flow above said predetermined pressure to said larger area of said piston for maximum and non-modulating engagement of said clutch to full clutch capacity,

and an electronic control circuit for the transmission including a source of pressurized fluid, a proportional valve connected to the source for delivering fluid to the reverse clutch, the source connected to another proportional valve for delivering the pressurized fluid to the forward clutch,

the circuit further includes a control lever operatively connected to the proportional valve for selective operation thereof to effect forward and reverse operation of the watercraft.