Marine transmission with a cone clutch used for direct transfer of torque

Marine transmission with a cone clutch used for direct transfer of torque

Abstract
A transmission of a marine propulsion system uses a cone clutch so that, when a forward drive position, the torque is transmitted from an input shaft or drive shaft to an output shaft or axle actuated solely by cone clutch. When the forward gear position, the driving torque between the driving and driven shafts is not transmitted through any gear teeth. When in reverse position, the torque is transmitted via a bevel gear assembly.
Description

Background of the Invention
1. Field of the Invention
The present invention generally relates to a marine transmission and, more particularly, to a marine transmission in which a drive shaft and a driven shaft are coaxially aligned for transferring torque directly through a cone clutch.
Two. Description of the Prior Art
Those skilled in the art of marine propulsion systems are aware of the many different types of transmissions which are used to provide the ability to enable the marine propulsion system to be operated in a neutral gear position and reverse into forward. Some of these transmissions are in the drive unit of a marine propulsion system tail Z. Other types of transmissions are between a motor inside the bilge of a marine vessel, and the transom of the marine vessel.U.S. Patent. No. 3,608,684, which issued to Shimanckas the September 28, 1971, describes a clutch for a marine propulsion device. The device allows the reverse rotation of the drive shaft housing around a vertical axis. Includes a clutch on the gearbox lower unit to selectively engage or disengage the propeller shaft with the drive shaft. The clutch is in response to axial movement of the drive shaft caused by moving a control handle accessible to the operator.U.S. Patent. No. 3,842,788, which issued to Kroll on October 22, 1974, describes a reversible transmission. The device includes a reversible or transmission clutch includes a pair of front drive gears rotatably mounted on a propeller shaft and having drive lugs, a driver movably mounted on the propeller shaft between the drive gears for axial movement relative to and in common rotation with the propeller shaft, a pair of dog clutch rotatably carried on the driver shaft of the propeller and having drive lugs that are engageable with lugs drive transmission respective drive gears and means for selectively moving the driver propeller shaft axially on the propeller shaft for engagement with a clutch claw actuating the gear drive.U.S. Patent. No. 3,919,964, which issued to Hagen on November 18, 1975, describes a reversing transmission with hydraulic assistance marine propulsion. The device comprises a reversing transmission located in a propulsion unit and the connection of a drive shaft to a propeller shaft and movable between neutral, forward travel, and rearward drive conditions, along with a mechanical connection extending in the propulsion unit and the connection for the transmission of reverse drive operation reverse in response to movement of the mechanical linkage. Also comprises a hydraulic arrangement driven in response to initial movement of the mechanical connection to help the movement of the mechanical linkage to operate the transmission in reverse.U.S. Patent. No. 3,943,790, which issued to Meyer on March 16, 1976, discloses a gear assembly outboard marine engine. It has a momentum of constant meshing gears that transfer powers to the shaft-propeller shaft and a spring-selective direct holding the propeller shaft. Using the meshing gears for circulating lubricant, as long as the engine is running and whether or not the clutch is engaged and which reduces to an absolute minimum, the resistance and the inertial effects on operation on the propeller shaft when the boat is moving in the disengaged condition.U.S. Patent. No. 4,244,454, which issued to Bankstahl on January 13, 1981, discloses a cone clutch. The cone clutch gear has its forward clutch and reverse supported by bearings mounted in the housing with a main shaft supported by bearings mounted in the housing in the same planes as the forward gear bearing and reverse. The male cone member is biased by two springs, each encircling cam faces on the bearing member and against clutch gears forward and reverse, respectively, to bias the cone member away from its center or neutral.U.S. Patent. No. 4,257,506, which issued to Bankstahl on March 24, 1981, discloses a shifter linkage for a cone clutch. The male cone member of a cone clutch mechanism has two springs, each cam faces surrounding the male cone member and bearing against the gear forward clutch and reverse, respectively, for biasing the cone away from its center or neutral position, either to the gear forward or reverse clutch. An eccentric roller on the axis shift actuator engages a circumferential groove in the male cone member to provide a vibration force against the displacement member.

U.S. Patent. No. 4,397,198, which issued to Borgersen et al. Aug. 9, 1983 discloses a system marine drivetrain. A drive assembly reversal double cone clutch for a boat comprising a horizontal input shaft, an output shaft intermediate vertical, a first housing having an opening in a side wall opposite to the input shaft and an opening in a wall background through which the lower end of intermediate output shaft is exposed, and selectable subsets transmission gear attached to the clutch drive assembly are described. Each subassembly includes a second housing with a generally horizontal wall to engage the bottom wall, the second housing containing a bearing which is mounted on an output shaft through gear means driven by the output shaft between.U.S. Patent. No. 4,630,719, which issued to McCormick on December 23, 1986, describes a mechanism to exchange torque with the aid pulsed impact. A cone clutch sleeve on a main shaft moves axially between forward and reverse gears rotate in opposite directions by a yoke having opposed mirror image cam tapered on opposite sides thereof that can be rotated to selectively engage the gears eccentric rings on back and forth. This compromise leads the yoke away from the gear engaged to the other gear to turn, driving the clutch sleeve out of engagement with the gear such that torque applied through the ring gear engaged cam clutch disengagement assists .U.S. Patent. No. 5,072,629, which issued to Hirukawa et al. on December 17, 1991, discloses an exchange system support. Describes the mechanism to assist the movement of a jaw clutch in a marine transmission by reducing the engine speed. The requirement for reducing the engine speed is detected by a pressure switch sensitive conductive rubber type pressure sensing contained within the internal connection between the operator and the dog clutch.U.S. Patent. No. 5,509,863, which issued to Mansson et al. April 23, 1996 describes a transmission device for the ship's engines. The transmission includes an input shaft, an investment mechanism and an output shaft. The reversal mechanism comprises a right-angle bevel gear with two bevel gears which are freely rotatably mounted on an intermediate shaft and engaged with a bevel gear on the input shaft. Bevel gears each cooperate with a single clutch, respectively, through which one of the bevel gears can be locked to the intermediate shaft. The clutches are placed outside the bevel gear. Clutches are wet clutches compressible by a piston that moves in a cylinder which in turn communicates with a hydraulic pump driven by one of the input and intermediate shafts.U.S. Patent. No. 5,709,128, issued to Skyman on January 20, 1998, describes the reverse gear of the boats. Describes a reverse gear on boats, comprising a coupling sleeve with a movable V-shaped groove There is a gear selector extends into the V-shaped groove in the form of a dog in a mobile bolt in the axial direction of the coupling sleeve. The pin is eccentrically mounted on a rotatable sleeve. A ball joint between the dog and the pin ensures that the dog will retain their orientation and contact area into the slot during the traversing movement.U.S. Patent. No. 5,890,938, which issued to Eick et al. on April 6, 1999, discloses a system of counter rotation marine propulsion. A system with counter-rotating propellers are provided with the ability to cause the propellers rotate at different speeds. A first gear is attached to an inner propeller shaft and a second gear is attached to an outer propeller shaft. The axes of the inner and outer helix are arranged in concentric coaxial relationship for rotation about an axis of rotation. A drive shaft connected to a pinion gear that engages with the teeth of the fore and aft gear in different effective diameters. Pinion gear meshes with a first plurality of gear teeth on a chamfered surface of the front sprocket, while a second set of gear teeth of the pinion gear mesh with a second plurality of gear teeth on a beveled surface rear axle. Because different effective diameters of the first and second plurality of gear teeth, the inner and outer shafts rotate at different speeds.U.S. Patent. No. 6,062,360, which issued to Shields on May 16, 2000, describes a synchronizer for a gear shift mechanism for a marine propulsion system. A gear change mechanism is provided synchronized marine propulsion system. The use of a hub and a sleeve that are axially movable relative to an output shaft, but rotationally fixed to the shaft and to each other, the gear change mechanism uses associated friction surfaces to bring the output shaft to a speed which is in synchronism with the selected forward or reverse gear prior to mating surfaces of the gear teeth associated together to transmit torque from an input shaft to an output shaft. The friction surfaces on the forward gears and reverse can be replaceable to facilitate repair after the wear of the friction surfaces experience.U.S. Patent. No. 6,523,655, issued to Behara on February 25, 2003, describes a connection rate of a marine drive unit. The linkage is provided with a slot which is aligned along a path which is not perpendicular to an axis of rotation of the shift linkage. The slot and the axis of rotation nonperpendicularity, allow detent ball to roll or slide along the slot smoothly. This ratio helps to keep the connection rate on a desired vertical position as it passes from one position to another gear selection.Patents described above are hereby expressly incorporated by reference in the description of the present invention.More sterndrive systems today use a transmission to switch between forward, neutral and reverse in one of four basic shapes. A complete package style hydraulic clutch transmission uses a planetary gear set for reverse. This type is mounted directly on the motor at the front tail board in U. Z They tend to be inefficient due to the use of a hydraulic pump, the clutch assemblies, and losses of the structure of large planetary set. This type of transmission also tend to be relatively large and requires more space on a marine vessel which is typically available in many types of ships.Another style of transmission is intentionally designed to be moved only when the engine is idle. This type usually uses a dog clutch and is primarily used for racing applications.A cone clutch style transmission is usually built on the upper drive shaft housing a sterndrive system. Generally have an input pinion meshing with two gears, one above and one below the line of center of rotation of the input pinion, which rotates around the axis of the vertical drive shaft. These gears are rotated in opposite directions and cone clutch engages a gear or the other to achieve forward or reverse gear selection. Engine power is transmitted through one of the gear sets at all times that the engine is running. Gears requirements are generally high due to the charge cycle to be handled. Ideally the gear geometry can be optimized, but the requirement that the cone clutch being mounted between the two driven gears limit this optimization.Another type of transmission that is often used is usually in the gearbox. Is similar in function to the cone clutch, except using a dog clutch, which is located for axial movement on the axis of the helix. A pinion drives two gears at all times. These gears are in the propeller shaft and rotating in opposite directions. Forward and Reverse gear positions are achieved engage the dog clutch with a gear or the other. The dog clutch teeth must be aligned before they can be activated. When the coupling components are rotating at different speeds, this may lead to excessive noise until the teeth actually engage each other.When using cone clutches, as described above, which are typically contained in the drive shaft housing. All engine power is transmitted via a pinion gear to the forward and reverse gears to be run continuously because of their constant mesh with the pinion gear. These applications usually maintain oil level in the transmission mesh dipping at least one gear.Would be significantly beneficial if the pair can be transmitted from a driving shaft to a driven shaft in forward gear, without having to transmit torque through the pinion and bevel gears mesh. It would also be significantly beneficial if gear meshes were not constantly submerged in gear oil. These features could improve operational efficiency and reduce the amount of heat generated by the transmission. Moreover, these features also enable the transmission more compact than known transmissions.
SUMMARY OF THE INVENTION
A transmission of a marine propulsion system in accordance with a preferred embodiment of the present invention comprises a first shaft supported for rotation about a first axis and a second shaft supported for rotation about a second axis. Comprises a clutch which is movable alternately in the first and second positions. When in the first position, the clutch is disconnected from the torque transmitting association with the first and second shafts and the first and second shafts are disconnected from the torque transmission connection with one another. When the clutch is in the second position, which is connected in torque transmitting association between the first and second axes, the torque is transferred from the first shaft to the second shaft through the clutch only.The present invention may further comprise a first bevel gear attached to the first axis and rotatable about the first axis and a second bevel gear which is rotatable about the second axis. An intermediate bevel gear is disposed in meshing relation with gear teeth between the first and second bevel gears. The clutch may alternatively be movable in a third position. When in the third position, the clutch is connected in torque transmitting association between the second bevel gear and the second axis. The first and second shafts are connected in torque transmitting relationship with each other through the first bevel gear, the intermediate bevel gear, the second bevel gear and the clutch when the clutch is in the third position.In a particularly preferred embodiment of the present invention, the first and second axes are generally parallel to each other and in a more preferred embodiment, the first and second axes are coaxial with each other. Intermediate bevel gear is rotatable about a third axis which is generally perpendicular to the first and second axes. The first shaft is connected in torque transmitting relation with the engine crankshaft and the second shaft is connected in relation to the torque transmission shaft of a propeller marine propulsion system. The clutch is connected in threaded engagement with the second axis through a set of helical grooves. In a preferred embodiment, the clutch is a cone clutch.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be more fully and completely understood from a reading of the description of the preferred embodiment in conjunction with the drawings, in which:Figures. 1-3 show various positions a dog clutch transmission;Figures. 4 and 5 show two positions in a cone clutch transmission;Figures. 6-8 show the present invention in a simplified set of representations to illustrate alternate positions of the cone clutch;Figures. 9A and 9B are sectional side views, respectively, of an intermediate shaft used in a preferred embodiment of the present invention;. The figure 10 shows a cone clutch is used in a preferred embodiment of the present invention, and. 11 is a sectional view of a transmission embodying the principles of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Throughout the description of the preferred embodiment of the present invention, like components will be identified by the same reference numerals.

. FIGURE Figure 1 shows a generally known type which provides a marine transmission input shaft 10 or the drive shaft and an output shaft 12 or driven shaft. The input shaft is connected to a first gear 16 which is used as a pinion gear. A forward gear 20 and reverse gear 22 are disposed in association constant mesh with the first gear 16. Be understood that the illustrations of FIGS. 1-8, bevel gears are shown slightly separated in order to clearly distinguish these components from one another. However, also be clearly understood that these gears are bevel gears which are disposed in continuous engagement tooth association with each other.With continued reference to FIG. 1, one can see that the rotation of the first gear 16, or drive gear 16, causes continuous rotation of both forward and reverse 20 bevel gear 22. The forward and reverse gears, 20 and 22 rotate in opposite directions, as shown by the arrows. A dog clutch 26 can move in an axial direction, which is horizontal in the figure. 1 between the bevel gears of forward and reverse. Moves relative to the output shaft 12 and is associated with the output shaft, in association threaded through a straight groove set in a manner that is well known by those skilled in the art of marine transmissions. With the dog clutch 26 in the position shown in Fig. 1, 22 or bevel gears 20 forward or reverse are connected rigidly to the second shaft 12 or driven shaft. As a result, the first and second bevel gears 20 and 22 rotate about their axes of rotation without affecting the output shaft 12.. Figure 2 shows the apparatus illustrated in Fig. 1, but with the dog clutch 26 is moved to the left to engage the teeth with the front bevel gear teeth 20. This coupling of the dog clutch teeth causes the dog clutch 26 to rotate in unison with the front bevel gear 20. Because the dog clutch 26 is associated in threaded engagement with the output shaft 12 due to association with the straight spline shaft, the output shaft 12 rotates in unison with the forward gear 20 and the dog clutch 26. The arrows indicate the rotation of the output shaft 12 rotates in the same direction as the front bevel gear 20.. Figure 3 illustrates the opposite condition, in which the dog clutch 26 is moved rightward in association with bevel gear meshing reverse 22. As a result, the dog clutch 26 rotates in unison with bevel gear 22 and reverse, due to the threaded association caused by the spline connection directly to the output shaft 12, second shaft 12 rotates in unison with bevel gear 22 reverse.With reference to FIGS. 1-3, it can be seen that axial movement of the dog clutch 26 to its limits of travel makes it the front bevel gear 22 or the reverse bevel gear 22 to rotate in unison with the dog clutch 26 for selecting the direction of rotation of the output shaft 12.With reference to FIG. 2 large arrows represent transmission of torque. As shown in the figure. 2, the torque is transmitted from the first shaft 10, or input shaft, with the first bevel gear 16 and then to the bevel gear 20 forward due to its association with teeth mesh with the first bevel gear 16. Forward bevel gear 20 then transmits torque to the dog clutch 26 which, in turn, transmits torque to the output shaft 12.With reference to FIG. 3, the torque transfer is from the first shaft 10 to the first bevel gear 16, and then, due to the association of the tooth mesh for the reverse bevel gear 22 and the dog clutch 26 which transmits the torque the output shaft 12.. Figure 4 shows a type generally known marine transmission which uses a cone clutch 30. When the cone clutch 30 is in a central position between the bevel gears 22, 20 forward and reverse gear, no torque is transferred from either of the two bevel gears to the output shaft 12. When the cone clutch 30 is moved upward, as shown in Fig. 4 placed forward gear 20 relative to the torque transmission to the output shaft 12, through cone clutch 30 which is provided with helical grooves which are engaged with matching grooves formed in the helical axis exit 12. A frictional connection between the upper portion of the cone clutch 30 and the mating friction surface formed in the bevel gear 20 is connected to the two friction in association with each other. This brings the cone clutch 30 to start to rotate in unison with the front bevel gear 20, and this in turn also urges the cone clutch 30 in an upward direction and in intimate frictional contact with bevel gear Front 20. When in this position, as shown in Fig. 4, the torque is transmitted from the input shaft 10 through the pinion gear 16, or first bevel gear to advance the bevel gear 20 and the output shaft 12 through the cone clutch 30.In the figure. 5, the cone clutch 30 is moved downward in frictional contact with the opening formed in the reverse bevel gear 22. In a manner generally similar to that described above in connection with FIG. 4 the spiral grooves urging the cone clutch 30 downwards in intimate frictional contact with the opening opposite the bevel gear 22 and the torque is transmitted from the input shaft 10 through the first bevel gear 16 for the gear reverse taper 22 at the cone clutch 30, and finally to the output shaft 12.Figures. 1-5 show how the two known types of marine transmissions operate. Figures. 1-3 illustrate the operation of a dog clutch system and figures. 4-5 illustrate a cone clutch system. One can observe that in all positions illustrated in FIGS. 2-5, the torque is transmitted via the gear teeth of the bevel gears in both forward and reverse.. Figure 6 is a schematic representation of the present invention which is deliberately simplified for clarity. A first shaft 41 is supported for rotation about a first axis 51. A second shaft 42 is supported for rotation about a second axis 52. A clutch 60 is reciprocally movable in a first position and a second position. The first position will be described below in connection with FIG. 7 and will be described below the second position in connection with FIG. August. A first bevel gear 71 is attached to the first shaft 41 and is rotatable about the first axis 51. A second bevel gear 72 can rotate about the second axis 52, but is free to rotate independently of the second shaft 42 when the clutch 60 is in a central position as shown in Fig. June. An intermediate bevel gear 73 is disposed in meshing gear tooth association between the first and second 71 and 72, the bevel gears. As described above, the bevel gears are in association with teeth that mesh with each other even though they are shown to be slightly separated for clarity in the illustrations. . Figure 6 illustrates the clutch 60 is moved to the first position, Fig. 7 illustrates the clutch 60 shifted to its second position, and Fig. Figure 8 shows the clutch 60 is moved to a third position.With continued reference to FIG. 6, an engine 80 has a crankshaft connected to the torque transmitting association with the first axle 41, or drive shaft. A drive unit 82, which is located behind the transom of a marine vessel is connected to the second shaft 42, or driven shaft. A drive shaft housing 84 is illustrated and the propeller shaft 86 is shown supported for rotation about an axis of propeller shaft 87. Those skilled in the art of marine propulsion systems are well aware of the various interconnections between the second shaft 42 and the propeller shaft 86 within the housing of the drive shaft 84 and the drive unit 82. Therefore, these interconnections known, are not described in detail herein.The motor 80 is contained within the hold of a marine vessel, with its crankshaft torque transmitting association with the first axis 41. When the clutch 60 is in the position shown in Fig. 6, no torque is transmitted from the first axis 41 to the second axis 42. However, it should be understood that the first, second, and intermediate bevel gears 71-73 rotate all because of its association with teeth mesh with each other and due to the rigid connection between the first bevel gear 71 and the first shaft 41. However, when the clutch 60 is not in frictional contact with either the first or second bevel gears 71 or 72, torque is transferred from either of these two bevel gear to the second shaft 42 or driven shaft.. Figure 7 shows the clutch 60 is moved in frictional engagement with the first bevel gear 71. For purposes of clarity and simplicity, the motor 80, the drive unit 82, the drive shaft housing 84, and the propeller shaft 86 are not illustrated in Fig. July.When the clutch 60 moves to the right as shown in Fig. 7, which is moved in frictional engagement with the friction surfaces formed within the first bevel gear 71. This, in turn, urges the clutch 60 to further friction coupling owing to the action of the spiral grooves that connect the clutch 60 to the output shaft or second axis 42. When in the position shown in Fig. 7, the torque is transmitted from the first shaft 41 to the first bevel gear 71, due to its rigid fixation to the first axis. Thereafter, the torque is transmitted from the first bevel gear 71 through the friction surfaces of contact, to the cone clutch 60. Since the cone clutch 60 is in meshing relationship with the second shaft 42 because of the spiral grooves, the torque is transmitted from the cone clutch 60 to the second axis 42. Importantly, although the first, second, and intermediate bevel gears are all continuously rotating due to its association with teeth mesh with each other, the torque is not transmitted through either the second bevel gear 72 or gear Intermediate 73 conical. In fact, the torque is not transmitted through any meshing teeth of any bevel gear. Instead, all the torque provided by the drive shaft or first shaft 41, is transmitted through the frictional engagement between the first bevel gear 71 and clutch 60 and through the spline connection between the clutch helical and the driven shaft 60 or second shaft 42. When in the position shown in Fig. 7, the inertial resistance to rotation provided by the second axle 42, in combination with helical spline connection between the clutch 60 and the second shaft 42 urges the clutch 60 in intimate frictional contact with the first bevel gear 71 to more efficiently transmit torque from the first shaft 41 to the second axis 42.When the clutch 60 moves to its third position, as shown in Fig. 8, the friction surface moves into contact with a mating friction surface formed in the second bevel gear 72. In combination with the action of the spiral grooves as described above, the inertial resistance provided by the second shaft 42 causes the clutch 60 to move into intimate frictional contact with the second bevel gear 72. The second bevel gear 72, as shown, rotates in a direction opposite to the first axis 41 and the first bevel gear 71. This is the result of the bevel gear 72 connected intermediate between the first and second bevel gears 71 and 72. As a result, torque is transmitted from the first shaft 41 to the first bevel gear 71, due to its rigid connection to the first axis, and then through the connection of the tooth, for the intermediate bevel gear 73. The connection between the conical intermediate gear tooth 73 and the second bevel gear 72 causes second bevel gear 72 to rotate in the direction shown. When the clutch 60 is in intimate frictional contact with the second bevel gear 72 which then transmits the torque through the clutch 60 for the second shaft 42. Throughout the figures. 1-8 larger broad arrows represent the path which transmits torque. The smaller line arrows represent the direction of movement.

. 9A shows an intermediate shaft 90 and Fig. 9B shows a sectional view of the same intermediate shaft 90. The intermediate shaft 90 is a component used in a transmission in accordance with a preferred embodiment of the present invention. . 10 illustrates a sectional view of a clutch 60, which is a component used in a preferred embodiment of the present invention. These two individual components work together to create a torque transmitting association between the clutch 60 and the second shaft 42 or driven shaft, as described above. The intermediate shaft 90 and the clutch 60, which are illustrated individually in Figs. 9A, 9B and 10, will also be described in connection with FIG. 11 in which the two individual components are assembled with other components in one embodiment of the present invention.With continued reference to FIG. 9, a central portion 91 of the intermediate shaft 90 is provided with a helical groove, which in a preferred embodiment comprises an involute thread start 12, which is also known as a helical spline. At one end 92, the intermediate shaft 90 is shaped to be slidably received in association within the structure of the first bevel gear 71. This enables the intermediate shaft 90 to rotate relative to the first bevel gear 71 that is rigidly attached to the first shaft 71. The other end 93 of the intermediate shaft 90 is splined. The slotted end 93 allows the intermediate shaft 90 which is coupled to a tail stock shaft of the transmission. This also facilitates the connection between the tail stock shaft and the second shaft 42 as described above.With reference to FIG. 10, the clutch 60 has an internally splined portion 94 which is threaded to engage the threads 91 of the intermediate shaft 90. A first friction surface 96 is formed to move in association with a mating friction surface of the first bevel gear 71. A second friction surface 97 is shaped to enter into frictional engagement with a friction surface of the second bevel gear 72. As described above, when any two friction surfaces 96 or 97, the clutch 60 begins to contact their mating surfaces of the friction associated first or second bevel gears 71 and 72, the resistance the second rotation axis 42, in combination with the threaded engagement of the spiral grooves, 91 and 94, further urge the friction surface of contact, 96 or 97, in intimate frictional contact with the friction surface associated with the first and second bevel gears, 71 or 72. Thus, torque is transmitted through the clutch 60.. 11 is a sectional view of a transmission incorporating the basic principles of the present invention. The reference numeral 101 identifies a flywheel of the internal combustion engine and the reference number 102 is the flexing of spring plate which is mounted on the wheel 101. The flexible plate 102 acts as a buffer for transmitting torque. Twisting the flexible plate is keyed to the input shaft 41, or drive shaft. The smaller projection (which extends to the right) is displayed on the input shaft 41 is a driver which protrudes into the end of the crankshaft of the engine and held in a position coaxial with the crankshaft. The first shaft 41, or drive shaft, is also grooved at its end opposite to the first bevel gear 71. A portion of the first bevel gear 71 is an outlet female cone clutch described above and illustrated in FIGS simply. 6-8. The first bevel gear 71 meshes with the intermediate gear 73. The intermediate bevel gear 73 is supported by the bearing 106.Spline to drill intermediate bevel gear 73 is a drive shaft of the pump 107 which, in turn, actuates a gerotor pump 108. Intermediate bevel gear 73 also meshes with the second bevel gear 72, which functions as a reverse bevel gear. Located between the first bevel gear 71 and the second bevel gear 72 is the clutch 60 having a friction cone surface on both sides male. These two male conical friction surfaces are described above and identified by reference numbers 96 and 97. The clutch 60 can engage with the friction coupling sockets formed in the first and second bevel gears 71 and 72. The clutch 60 is connected to the intermediate shaft 90 through a helical groove arrangement comprising the spiral grooves 91 and 94 as described above in connection with FIGS. 9 and 10.With continued reference to FIG. 11, a shift lever 113 is a yoke-shaped displacement fork that fits into a slot on the outside diameter of the clutch 60. A lever 112 is fixed to a shift shaft 114. The shift shaft 114 has a ramp or cam on the sides of the holder that engages with the shift lever 113.The friction created between the conical friction surfaces start to turn the cone clutch 60 relative to the intermediate shaft 90. Because of the association of helical splined coupling between the ridges 94 of the clutch 60 and the splines 91 of the intermediate shaft 90, clutch 60 is pulled tighter to the first bevel gear 71. This is caused by the inertial rotation resistance initially provided by the second shaft 42 as the input shaft 41 continues to rotate the first bevel gear 71. More torque transferred through the intermediate shaft 90 causes a greater clamping load generated between the surfaces of friction clutch coupling. Note that, when in forward gear position, the torque is transmitted through the first bevel gear 71 to the clutch 60 and the intermediate shaft 90 and tail stock shaft 115 and the U 116 the second axis 42 . Very little torque is transmitted through the gears 71 to 73, except for the small amount of torque is used to drive the gerotor pump 108.With continued reference to FIG. 11 reverse connection moving the clutch 60 toward the second bevel gear 72 until contact is made between the mating clutch surfaces. The torque is transmitted from the first bevel gear 71 to the intermediate bevel gear 73 and the second bevel gear 72. Is then transmitted to the clutch 60 to the intermediate shaft 90 and tail stock shaft 115 and U-joint 116 of the second shaft 42. Due to the helical spline connection between the intermediate shaft 90 and the clutch 60, the increase in torque transmitted through the cone clutch increases the contact force between the clutch faces.Another advantage provided by the present invention is the reduction in friction losses with air. A return sump 120 is located below all swivel bearings and gears. Gerotor pump 108 draws oil from the sump 120 located in housing 117 and the pressure induces oil flow to all critical rotating components. The system is designed so that the oil flows back to the sump 120 to minimize contact with the rotating components and as a result, to reduce windage losses.With continued reference to FIG. 11 illustrates the exterior mirror housing 130 of a marine propulsion system. As may be in itself, transmission provided by the present invention is forward of the transom and the drive unit 82 is aft of the transom housing outside 130.With reference to FIGS. 6-11 can be seen that the present invention provides a first axis 41, or drive shaft, supported for rotation about a first axis 51. A second shaft 42 or driven shaft is supported for rotation about a second axis 52. A clutch 60 is reciprocally movable in a first position, shown in Fig. 6, and a second position shown in Fig. July. The first position disconnects the clutch 60 of the torque transmitting association with the first and second shafts, 41 and 42, and also disconnects the first and second transmission shaft torque relationship with one another. The second position connects the clutch 60 in torque transmitting association between the first and second shafts, 41 and 42, the torque is transferred from the first axis 41 to the second shaft 42 only via the clutch 60. A first bevel gear 71 is attached to the first shaft 41 and rotatable about the first axis 51. A second bevel gear 72 can rotate about a second axis 52. An intermediate bevel gear 73 is disposed in meshing gear tooth association between the first and second bevel gears 71 and 72. The clutch 60 is reciprocally movable in a third position, illustrated in FIG. 8, the clutch 60 is connected in torque transmitting association between the second bevel gear 72 and the second shaft 42. The first and second shafts, 41 and 42 are then connected in connection with transmitting torque to each other through the first bevel gear 71, the intermediate bevel gear 73, the second bevel gear 72 and the clutch 60 when the clutch is in the third position shown in Fig. August. The first and second shafts, 51 and 52 are generally parallel to each other and, in a preferred embodiment, are mutually coaxial. The intermediate bevel gear 73 is rotatable about a third axis 53 that is generally perpendicular to the first and second shafts, 51 and 52. The first shaft 41 is connected in torque transmitting relation with a crankshaft of an engine 80. The second shaft 42 is connected in connection with transmitting torque to the propeller shaft 86. The clutch 60 is connected in threaded engagement with the second shaft 42 through a set of helical grooves, 91 and 94. The clutch 60, in one preferred embodiment of the present invention is a cone clutch.Although the present invention has been described with particular detail and illustrated to show specific embodiments, it should be understood that alternative embodiments are also within its scope.