Abstract
In a marine transmission, the rear faces of each of a plurality of engaging projections that extend axially from a forward gear are provided with an angle of attack. The inclination angle of each outlet face cooperates with an associated surface of each of a plurality of projections for retaining a clutch dog clutch in an axial position with respect to forward movement, even during periods in which a vessel Navy is decelerating rapidly, and as a result, the dog clutch is moved in relation to the forward driving gear.
Description
Background of the Invention
1. Field of the Invention
The present invention generally relates to a transmission mechanism for a marine propulsion device, and more particularly, to a system that retains a clutch mechanism in its correct position when the driven shaft is rotated at a higher speed than its axis associated drive.
Two. Description of Related Art
Those skilled in the art of marine propulsion devices are familiar with many different structures and techniques used to transfer torque from a drive shaft to a driven or propeller shaft.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 for the reverse rotation of the drive shaft housing about a vertical axis. Includes a clutch on the gearbox lower unit to selectively engage or disengage the propeller shaft with the shaft. The clutch is in response to axial movement of the shaft caused by moving a control lever for operator access.U.S. Patent. No. 4,223,773, which issued to Croissant et al. September 23, 1980, discloses a drive coupling apparatus. A clutch apparatus for a unit of marine lower gearbox includes a propeller shaft rotatably mounted in a housing of the gearbox. A drive gear for both forward and backward in the housing is positioned coaxially with the propeller shaft and the clutch member is rotatably secured to the propeller shaft and movable axially in driving engagement with the gear drive. Clutch engagement elements are provided on opposite sides of the drive gears and the clutch member. Shift means using a positive-acting cam means positively move the clutch in and out of engagement of the drive gears. Change means also include means for releasably maintaining a latch positively change means in the engaged position and a means of preload between the changing means and the clutch to engage the clutch in engagement.U.S. Patent. No. 4,302,196, which issued to Blanchard on November 24, 1981, describes a marine propulsion unit including propeller thrust axis transmission media. The marine propulsion device includes a drive shaft housing mounted for vertical swinging movement about a horizontal axis relative to a ship, a propeller shaft rotatably mounted on the drive shaft housing and having an axis rotation and carried by the propeller shaft of the propeller. The marine propulsion device also includes a first bevel gear mounted on the drive shaft housing and in coaxial relation with the axis of the helix, a second bevel gear mounted on the drive shaft housing and in coaxial relation with the axis of the propeller, and a clutch mechanism operable to selectively connect the bevel gears in the propeller shaft.U.S. Patent. No. 4,986,774, which issued to Wantz on January 22, 1991, discloses a desmodromic change adapter for a set of axis counter-rotating propeller. The adapter member accommodates the use of a displacement mechanism desmodromic cam actuated. The adapter includes a cup element which is adapted to mount the foreground one of the marches back and forth through a bearing member. The adapter element further includes an inner conduit which is disposed within the movable cam shifting mechanism, and an opening in communication with the passage to allow the connection shaft to change the offset cam member after assembly of adapter in the gearbox cavity.
SUMMARY OF THE INVENTION
A transmission of a marine propulsion device, made according to a preferred embodiment of the present invention comprises a propeller shaft supported for rotation about an axis of propeller shaft, and first and second gears are arranged to rotation about the shaft axis. A transmission shaft is supported for rotation about a shaft axis which is generally perpendicular to the axis of the helix axis into a preferred embodiment of the present invention. A drive gear is fixed for rotation with the shaft. The first and second gears are arranged in meshing relation with the drive gear for rotation in opposite directions from one another about the axis of the helix. A dog clutch is attached to a shaft rotating with the propeller around the propeller shaft axis and between the first and second gears. The dog clutch is movable parallel to the axis of the drive shaft in a first direction toward the first gear and away from the second gear and in a second direction toward the second gear away from the first gear. A first plurality of projections extending from clutch dog clutch in a direction towards the first gear. A second plurality of engaging projections extend from the first gear in a direction toward the dog clutch. Each of the first plurality of projections has a front face gear and output side. The front face and rear face are each disposed at an angle of inclination which is greater than one degree.In a preferred embodiment of the present invention, the front face and rear face are each arranged at a right angle that is greater than three degrees and in a particularly preferred embodiment of the present invention, the anterior and later are arranged on each angle of attack which is generally equal to five degrees.A second plurality of engaging projections extend from the second gear in a direction toward the dog clutch. Each of the second plurality of projections gear having a front face and exit face. The front face is disposed at an angle that is greater than one degree and the outlet face is disposed at an angle which is generally equal to zero degrees. In one embodiment of the present invention, the first side and the second side are each arranged at an inclination angle that is greater than one degree. The first face of each of the first plurality of clutch protrusions is disposable in contact relationship with the associated front face of the first plurality of projections gear when first gear is in driving relationship with the dog clutch and the rake face of each of the first plurality of engaging projections is providing a driving force against the first side of an associated one of the first plurality of clutch protrusions in order to cause the dog clutch and the axis of the helix to rotate in synchrony with the first gear. The second face of each of the first plurality of clutch protrusions is disposable in contacting relation with the exit face of an associated one of the first plurality of projections of the clutch gear when the dog is in driving relation with the first gear and the second face of each of the first plurality of clutch protrusions is providing a drive force against the rear face of the associated one of the first plurality of projections for engaging the dog clutch and the axis of the helix to rotate in synchrony with the first gear.In a preferred embodiment of the present invention, the dog clutch is connected to the propeller shaft by a plurality of spline teeth. The first gear may be a forward gear, when the plurality of teeth projections engaged in driving relationship with the first plurality of projections of clutch, a propeller of the marine propulsion system that rotates in one direction exerts a force on one associated marine vessel in a direction forwards. The first and second bevel gears may be the drive gear and can also be a bevel gear which is in mesh relationship with the first and second gears.
BRIEF DESCRIPTION OF THE DRAWINGS
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 1 is a sectional view of a marine propulsion device 10 which incorporates a preferred embodiment of the present invention. In a manner that is generally familiar to those skilled in the art, a drive shaft 14 is supported for rotation about a generally vertical axis 16. A lower portion of the drive shaft 14 is connected to a drive gear 18 which is also rotatable about the axis of shaft 16. The first and second gears 20 and 22 are supported for rotation about an axis of propeller shaft 26. A propeller shaft 30 is supported for rotation about the shaft axis 26.With continued reference to FIG. 1, the components described above are supported within a gear box structure 40. For general reference purposes, the structure of the gear box 40 has a heel 42 which extends downwardly from its outer surface. The bead 42 is partially illustrated in Fig. 1. A helix structure 50 is shown attached to the propeller shaft 30 for rotation about the axis of the propeller shaft 26. A shift shaft 56 is supported for rotation about a generally vertical axis and is operatively associated with a horizontally disposed axis 60 that allows a dog clutch 70 to be moved axially in a direction parallel to the propeller shaft 26 when the shaft Exchange 56 is rotated about its central axis.. Figure 2 is an enlarged representation of a portion of the structure shown in Fig. 1. With reference to FIGS. 1 and 2, those skilled in the art are familiar with the basic operation of the structure illustrated. When an associated internal combustion engine is operating, the drive shaft 14 rotates continuously about its axis shaft 16. The drive gear 18 is attached to the lower portion of the drive shaft 14 rotates continuously with it. The drive gear 18 is continuously meshing relation with the teeth of the first and second gears 20 and 22. The first and second gears are supported for rotation about the axis of shaft 26 in a manner that is generally independent of the propeller shaft 30. In other words, the first and second gears 20 and 22 can rotate around the axis of the drive shaft 26 without causing the propeller shaft 30 to rotate. This kind of operation occurs when the transmission is in a neutral position. Because of the association between the meshing of the drive gear 14 and the first and second gears 20 and 22, the first and second gears 20 and 22 rotate in opposite directions around the axis of the propeller shaft 26 in all conditions . The dog clutch 70 can move in a direction that is generally parallel to the axis of propeller shaft 26 in response to rotation of the shift shaft 56 about its central axis 57.With continued reference to FIGS. 1 and 2, it should be understood that the first and second gears 20 and 22, are typically arranged so that the participation of these two gears causes the propeller shaft 30 to rotate in a direction that drives a marine vessel in a forward direction. This is one of the first and second gears 20 and 22 is the forward gear as a result of the direction of rotation of the transmission shaft 14 on the shaft axis 16 and the pitch of the blades 80 of the propeller 50. However, it should be clearly understood that the selection of forward motion, since the election of the first and second gears 20 and 22 is not limiting to the scope of the present invention. In other words, the basic concept of the present invention can be used to improve the operation of the transmission for a marine propulsion device at either of the two alternatives described above circumstances. For purposes of illustrating and describing a preferred embodiment of the present invention, the first gear 20 is supposed to be the forward gear and the second gear 22 is supposed to be the reverse gear.. Figure 3 is an isometric view of the first gear 20. As described above, the first gear shown in Fig. 3 assumes that the speed of the marine propulsion system. In the figure. 3 does not show the gear teeth of the bevel gear, located in the region identified by reference numeral 88. However, it should be understood that the teeth are provided in this region, in a manner that is very familiar to those skilled in the art, and configured along the surface of the region 88 which is formed generally in the shape of a frustum of a cone. The first gear 20 is shown in Fig. 3 is configured to be rotatable about the axis of shaft 26 with its internal cylindrical surface 90 that can rotate around an outer surface of the propeller shaft 30 as illustrated in FIGS. 1 and 2. It should be understood, however, that the inner cylindrical surface 90 is supported in noncontact association with associated outer surface of the propeller shaft 30. This relationship is maintained so that the rotation of the first gear 20 is independent of the rotation of the propeller shaft 30, unless these two components are joined together by the jaw clutch 70 described above.With reference to FIGS. 1-3, the first gear 20 is supposed to rotate in the direction shown by arrow R in Fig. Three. A plurality of engaging projections 100 extending from the first gear 20, as shown in Fig. 3, in a direction toward the dog clutch 70. Each of the first plurality of engaging projections 100 has a front face 101 and a rear face 102.. Figure 4 is an isometric view of the dog clutch 70. As shown, the dog clutch 70 is rotatable about the axis of shaft 26. A first plurality of clutch projections 200 extending from the dog clutch 70 in a direction toward the first gear 20. This first plurality of clutch projections 200 is illustrated as extending toward the left in FIG. April.
With continued reference to FIGS. 3 and 4, those skilled in the art of marine transmissions are familiar with the fact that the dog clutch 70 is attached to the propeller shaft 30 as illustrated in FIGS. 1 and 2, a plurality of spline teeth. Internal spline teeth of jaw clutch 70 is identified by reference numeral 210 in FIG. April. This arrangement gives the clutch spline claws 70 to the propeller shaft 30 for synchronous rotation therewith.Each of the first plurality of clutch protrusions 200 has a first face 201 and a second side 202. The first and second faces of each of the first plurality of clutch protrusions 200 are each arranged at an inclination angle that is greater than one degree and, in one particularly preferred embodiment of the present invention is generally equal to about five degrees. As described in greater detail below, these angles of inclination of the first and second faces 201 and 202, resulting in the fact that these first and second faces are disposed in individual planes are not parallel to the propeller shaft 26 .With continued reference to FIG. 4, it should be clearly understood that it is well known to those skilled in the art of marine propulsion systems to the first and second faces 201 and 202, the dog clutch 70 are configured at angles of incidence greater than zero degrees. This is done although the second faces 202 of the plurality of projections clutch 200 is not meant to be placed in direct contact with the plurality of engaging projections 100 described above in connection with FIG. Three. This arrangement of the angles of attack of the second faces 202 of the dog clutch 70 is made as a convenience for the manufacture of the dog clutch. In other words, a milling cutter is typically set to form adjacent first and second faces, 201 and 202, between the projections adjacent clutch during a single pass of the cutter in a direction which forms two diametrically opposed holes of the opposing pairs clutch projections 200 in one pass. As a result, a second face 202 of each clutch boss 200 is formed with an angle greater than zero degree although not intended to ever be placed in direct contact with an associated surface of the first gear 20.With continued reference to FIGS. 3 and 4, it should be understood that when the dog clutch 70 is moved axially in a direction parallel to the axis of propeller shaft 26 so that the first plurality of clutch protrusions 200 moves in contact with the first plurality of engaging projections 100, the leading face 101 of each of the plurality of engaging projections 100 moves in contact with a first side 201 associated one of the plurality of projections clutch 200. The arrows R in Figs. 3 and 4 show the resulting rotation of the first gear 20 and the dog clutch 70 in synchronism with each other about the axis of shaft 26. This engagement of the plurality of projections 100 engaging with the plurality of projections 200 causes the clutch dog clutch 70 to rotate synchronously with the first gear 20 about the axis of shaft 26. The splined connection between the dog clutch 70 and propeller shaft 30 causes the propeller shaft 30 to rotate about the axis of shaft 20. In other words, the engagement of the clutch plurality of projections 200 with the plurality of engaging projections 100 result in the transfer of torque from the transmission shaft 14 to the propeller shaft 30 in the direction dictated by the direction of rotation the first gear 20 on the shaft of the propeller shaft 26. This basic operation of the components illustrated in FIGS. 1-4 is generally known to those skilled in the art.With continued reference to FIGS. 1-4, it should be understood that under certain circumstances, the propeller shaft 30 can be rotated at a higher speed than the first gear 20. More typically, this situation can arise when there is a rapid deceleration of the drive shaft 14. In other words, when the operator of a marine vessel quickly decreases the operating speed of a related internal combustion engine, the drive shaft 14 decelerates faster than the propeller shaft 30. Moreover, the movement of the propeller 50 through the water at the speed of the marine vessel 80 causes the blades to exert torque on the propeller shaft 30 to induce continuous rotation at a speed that is greater than the speed Rotation of the first gear 20. When this occurs, the leading face 101 of each of the plurality of engaging projections 100 can be uncoupled from the associated first side 201 of the plurality of projections clutch 200. In marine transmissions known to those skilled in the art, the outlet face 102 of each of the plurality of engaging projections 100 are configured to have any angle. In other words, the effective tilt angle of each of the rear sides 102 is generally equal to zero. As a result, the separation between the leading faces 101 of the plurality of projections of the first gear 100 and 201 faces the plurality of clutch projections 200 can allow the separation between the jaw clutch 70 and the first gear 20 as a result of the tendency of the dog clutch 70 is moved axially away from the first gear 20. Deceleration during these conditions, the rotational speed of the dog clutch 70 typically exceeds the rotational speed of the propeller shaft 30 due to the hydrodynamic effect of the blades 80 as they move through the water at the speed of the boat associated marine. The resulting speed of the propeller shaft 30 and the dog clutch 70 is greater than the rotational speed of the first gear 20 which is in contact engagement with the drive gear 18 which is attached to shaft 14. From the exit faces 102 of the plurality of engaging projections 100 have a rake angle of essentially zero degrees forward speeds known to those skilled in the art, the dog clutch 70 can be easily moved axially away from the gear forward. This makes the separation between the plurality of clutch projections 200 and the plurality of projections 100 engaging in transmissions known to those skilled in the art.
With continued reference to FIGS. 1-4, looking at the back 102 of the plurality of engaging projections 100, in fact a first gear according to a preferred embodiment of the present invention, the area of each outlet face 102 is provided with an angle of attack greater than zero degrees. In a particularly preferred embodiment of the present invention, this angle is approximately equal to five degrees. Because the second face 202 of each of the outgoing clutch 200 is normally provided with an inclination angle due to manufacturing efficiencies described above, the rotation of the dog clutch 70 at speeds greater than the rotation of the first gear 20 will tend to make the second faces of the projections 202 of clutch 200 to move into contact with the driving faces 102 of the plurality of engaging projections 100. Since both sides of the second drive faces 102 and 202 have an angle of approximately five degrees, the dog clutch 70 is retained in operating engagement with the first gear 20 even though the propeller shaft 30 is rotating at a speed greater than the first gear 20 during periods of time when the marine vessel is decelerating rapidly. This retention of the dog clutch 70 in engagement with the first gear 20 provides a significant advantage to prevent axial movement of the dog clutch 70 away from the first gear 20 when a rapid deceleration.Figures. 5A and 5B are developed views showing the relationship between the plurality of engaging projections 100 and the plurality of clutch projections 200. R arrows are provided to show the directions of rotation of the components.In the figure. 5A, the first gear 20 provides torque, via its connection with the drive gear 18 for the dog clutch 70. This results in the front face 101 which is in direct contact with the first face 201. In a typical arrangement of the first gear and dog clutch, both the front face 101 and the first side 201 is provided with an inclination angle θ of about five degrees. The tilt angles θ of the front face 101 and the first face 201 helps to maintain the gear ratio between the first gear 20 and the dog clutch 70 when the first gear 20 is driving the dog clutch 70. This ratio is generally known to those skilled in the art.. 5B shows the relative positions of the plurality of engaging projections 100 and the plurality of projections 200 when the clutch during periods of rapid deceleration of the marine vessel, the dog clutch 70 is connected with the first driving gear 20 . As described above, this occurs when the hydrodynamic forces on the blades 80 of the propeller 50 causes the propeller shaft 30 to attempt to move at a speed of rotation around the axis of the helix 26 which is greater than the speed of rotation the first gear 20 on the same axis that.
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