Outboard motors having transmissions with laterally offset input and output driveshafts

Abstract

An outboard motor comprises an engine; an input driveshaft that is caused to rotate by the engine; an output driveshaft that extends parallel to and is laterally spaced apart from the input driveshaft; and a transmission that operatively connects the input driveshaft to the output driveshaft such that rotation of the input driveshaft causes rotation of the output driveshaft. The transmission is positionable into a forward gear in which forward rotation of the input driveshaft causes forward rotation of the output driveshaft, a reverse gear in which forward rotation of the input driveshaft causes reverse rotation of the output driveshaft, and neutral wherein forward rotation of the driveshaft does not cause rotation of the output driveshaft.

Claims

1. An outboard motor comprising: an engine; an input driveshaft that is caused to rotate by the engine; an output driveshaft that extends parallel to and is laterally spaced apart from the input driveshaft; a transmission that operatively connects the input driveshaft to the output driveshaft such that rotation of the input driveshaft causes rotation of the output driveshaft, wherein the transmission is positionable into and between a forward gear in which forward rotation of the input driveshaft causes forward rotation of the output driveshaft, a reverse gear in which forward rotation of the input driveshaft causes reverse rotation of the output driveshaft, and neutral wherein forward rotation of the input driveshaft does not cause rotation of the output driveshaft; and a propulsor shaft that transversely extends relative to the output driveshaft and a beveled gearset that operatively couples the output driveshaft to the propulsor shaft so that rotation of the output driveshaft causes rotation of the propulsor shaft.

2. The outboard motor according to claim 1, wherein the transmission comprises a reverse driving gear on the input driveshaft and a reverse driven gear on the output driveshaft; and wherein in the reverse gear, forward rotation of the input driveshaft causes forward rotation of the reverse driving gear, which causes reverse rotation of the reverse driven gear, which causes reverse rotation of the output driveshaft.

3. The outboard motor according to claim 2, wherein the transmission comprises a forward driving gear on the input driveshaft, a forward driven gear on the output driveshaft, and an idler gear meshed between the forward driving gear and the forward driven gear, wherein in forward gear, forward rotation of the input driveshaft causes forward rotation of the forward driving gear, which causes reverse rotation of the idler gear, which causes forward rotation of the forward driven gear, which causes forward rotation of the output driveshaft.

4. The outboard motor according to claim 3, wherein the transmission comprises a cone clutch that is operable to position the transmission into the forward gear, reverse gear and neutral.

5. The outboard motor according to claim 4, wherein the cone clutch comprises a central cone that is coupled to the input driveshaft so that rotation of the input driveshaft causes rotation of the central cone in each of the forward gear, reverse gear, and neutral, wherein the central cone is positionable along the input driveshaft into and between a reverse position in which the central cone enacts the reverse gear, a forward position in which the central cone enacts the forward gear and a neutral position in which the central cone enacts neutral.

6. The outboard motor according to claim 5, wherein the cone clutch further comprises a reverse cone fixed to the reverse driving gear, wherein in the reverse gear, the central cone engages the reverse cone so that rotation of the central cone causes rotation of the reverse cone and thus the reverse driving gear.

7. The outboard motor according to claim 6, wherein the cone clutch further comprises a forward cone fixed to the forward driving gear, wherein in the forward gear, the central cone engages the forward cone so that rotation of the central cone causes rotation of the forward cone and thus the forward driving gear.

8. The outboard motor according to claim 7, further comprising a shift actuator that is configured to move the central cone along the input driveshaft so as to enact the reverse, neutral and forward gears.

9. The outboard motor according to claim 8, further comprising a detent mechanism that detents the shift actuator in neutral position.

10. The outboard motor according to claim 9, wherein the detent mechanism is spring actuated.

11. The outboard motor according to claim 8, further comprising a camming mechanism that cams the shift actuator up and down upon rotation of the shift actuator back and forth, wherein movement of the shift actuator up and down causes movement of the central cone up and down, respectively.

12. The outboard motor according to claim 1, further comprising a lubrication circuit that provides lubrication to the transmission.

13. The outboard motor according to claim 12, further comprising a lubrication pump coupled to the input driveshaft such that rotation of the input driveshaft causes the lubrication pump to pump lubrication through the lubrication circuit.

14. The outboard motor according to claim 13, further comprising a lower gearcase that encases the beveled gearset, wherein the lubrication circuit comprises a lubrication reservoir in the lower gearcase, wherein the lubrication pump draws lubrication from the lubrication reservoir and pumps the lubrication to the transmission.

15. The outboard motor according to claim 14, wherein the lubrication pump pumps the lubrication to the transmission via an axial channel and a plurality of transverse openings in the input driveshaft.

16. The outboard motor according to claim 15, further comprising a replaceable filter in the lubrication circuit, wherein the lubrication pump pumps the lubrication through the replaceable filter and then to the transmission via the axial channel and plurality of transverse openings.

17. The outboard motor according to claim 16, further comprising a check valve that opens under pressure from the lubrication when the replaceable filter becomes plugged.

18. The outboard motor according to claim 1, further comprising a propulsor that rotates with the propulsor shaft.

19. The outboard motor according to claim 8, wherein the propulsor comprises a pair of counter rotating propulsors that are driven by the propulsor shaft.

20. An outboard motor comprising: an engine; an input driveshaft that is caused to rotate by the engine; an output driveshaft that extends parallel to and is laterally spaced apart from the input driveshaft; a transmission that operatively connects the input driveshaft to the output driveshaft such that rotation of the input driveshaft causes rotation of the output driveshaft, wherein the transmission is positionable into a forward gear in which forward rotation of the input driveshaft causes forward rotation of the output driveshaft, a reverse gear in which forward rotation of the input driveshaft causes reverse rotation of the output driveshaft, and neutral wherein forward rotation of the driveshaft does not cause rotation of the output driveshaft; a propulsor shaft that transversely extends relative to the output driveshaft; a beveled gearset that operatively couples the output driveshaft to the propulsor shaft so that rotation of the output driveshaft causes rotation of the propulsor shaft; wherein the transmission comprises a reverse driving gear on the input driveshaft and a reverse driven gear on the output driveshaft; and wherein in the reverse gear, forward rotation of the input driveshaft causes forward rotation of the reverse driving gear, which causes reverse rotation of the reverse driven gear, which causes reverse rotation of the output driveshaft; wherein the transmission comprises a forward driving gear on the input driveshaft, a forward driven gear on the output driveshaft, and an idler gear meshed between the forward driving gear and the forward driven gear, wherein in forward gear, forward rotation of the driveshaft causes forward rotation of the forward driving gear, which causes reverse rotation of the idler gear, which causes forward rotation of the forward driven gear, which causes forward rotation of the output driveshaft; wherein the transmission comprises a cone clutch that is operable to position the transmission into the forward gear, reverse gear and neutral; a lubrication circuit that provides lubrication to the transmission; a lubrication pump coupled to the input driveshaft such that rotation of the input driveshaft causes the lubrication pump to pump lubrication through the lubrication circuit; and a lower gearcase that encases the beveled gearset, wherein the lubrication circuit comprises a lubrication reservoir in the lower gearcase, wherein the lubrication pump draws lubrication from the lubrication reservoir and pumps the lubrication to the transmission.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The drawings illustrate the best mode presently contemplated of carrying out the concepts of the present disclosure. The same numbers are used throughout the drawings to reference like features and like components. In the drawings:

(2) FIG. 1 is a perspective view of a lower gearcase on an outboard motor.

(3) FIG. 2 is a perspective view looking downward at a transmission for the outboard motor.

(4) FIG. 3 is a perspective view looking upward at the transmission.

(5) FIG. 4 is an exploded view of the transmission.

(6) FIGS. 5-7 are view of section 5-5 taken in FIG. 1, showing alternative power flows through the transmission.

(7) FIG. 8 is a view of section 5-5 taken in FIG. 1, showing a lubrication circuit for the transmission.

DETAILED DESCRIPTION OF THE DRAWINGS

(8) During research and development of outboard motors, the present inventors have determined that dual propeller outboard motors offer several performance improvements over single propeller motors. However it can be difficult to design a dual propeller outboard motor that meets all performance goals and has little detrimental impact to the overall design of the outboard motor. Typical outboard motors transfer power through a driveshaft from a powerhead to a right angle gearset (i.e. a pinion with forward and reverse gears) that turns a propeller shaft. Shifting is typically accomplished with a clutching system, typically a dog clutch, which is moved from one gear to the other depending on the user's command. Through research and development, the present inventors have invented a transmission assembly for an outboard motor that allows use of several different types of clutching systems and adds an additional gear set and pressure lubrication to utilize dual counter rotating propellers within a traditional outboard motor structure. The transmission apparatuses disclosed herein provide simple direct mechanical activation of a shifting mechanism, to thereby provide a durable system for consistent performance. Dual parallel driveshafts allow for utilization of a simple gearset to provide the proper total output ratio. Several different clutching options provide function within a minimum package size. Dual floating idler gears provide power transfer within a minimum package size. A lubrication circuit provides lubrication where needed. A replaceable filter provides protection from debris in the system.

(9) FIGS. 1-8 depict portions of an outboard motor 10 according to the present disclosure. The outboard motor 10 includes a transmission housing 12 and a lower gearcase housing 14, which are located below a (not shown) driveshaft housing of the outboard motor 10. The outboard motor 10 includes an internal combustion engine, shown schematically at 16 in FIG. 1. As is conventional, the internal combustion engine 16 is configured to cause rotation of an input driveshaft 18 that extends along an input driveshaft axis 20 into the transmission housing 12.

(10) Referring to FIGS. 2-7, a transmission 22 operatively connects the input driveshaft 18 to an output driveshaft 24 that extends parallel to and is laterally spaced apart from the input driveshaft 18. As described further herein below, the transmission 22 is positionable into and between a forward gear (FIG. 6) in which forward rotation of the input driveshaft 18 causes forward rotation of the output driveshaft 24, a reverse gear (FIG. 7) in which forward rotation of the input driveshaft 18 causes reverse rotation of the output driveshaft 24, and neutral (FIG. 5) wherein forward rotation of the input driveshaft 18 does not cause rotation of the output driveshaft 24.

(11) Referring to FIGS. 5-7, a propulsor shaft 26 transversely extends relative to the output driveshaft 24. The propulsor shaft 26 is located in the lower gearcase housing 14 and is rotationally connected to a propulsor 28 (see FIG. 1) which rotates with the propulsor shaft 26. In the illustrated example, the propulsor 28 includes a pair of counter rotating propellers 30 that are configured to interact with the surrounding body of water to propel the marine vessel to which the outboard motor 10 is attached. The type and configuration of the propulsor 28 can vary from that which shown and for example can include different propeller configurations, impellers, and/or the like. A conventional beveled gearset 31 (see FIGS. 5-8) operatively couples the output driveshaft 24 to the propulsor shaft 26 so that rotation of the output driveshaft 24 causes corresponding rotation of the propulsor shaft 26.

(12) Referring to FIGS. 2-7, the transmission 22 includes a reverse driving gear 32 on the input driveshaft 18 and a reverse driven gear 34 on the output driveshaft 24. The reverse driving rear 32 is rotatably fixed to the input driveshaft 18 and the reverse driven gear 34 is rotatably fixed to the output driveshaft 24. The reverse driving gear 32 and reverse driven gear 34 are meshed together such that forward rotation of the input driveshaft 18 causes forward rotation of the reverse driving gear 32, which thereby causes reverse rotation of the reverse driven gear 34. Reverse rotation of the reverse driven gear 34 causes reverse rotation of the output driveshaft 24. Reverse rotation of the output driveshaft 24 causes reverse rotation of the propulsor shaft 26, via the beveled gearset 31. Reverse rotation of the propulsor shaft 26 causes the propulsor 28 to rotate so that a reverse thrust is imparted on the marine vessel.

(13) The transmission 22 also includes a forward driving gear 37 on the input driveshaft 18, a forward driven gear 38 on the output driveshaft 24, and a pair of idler gears 40 that is meshed between so as to connect the forward driving gear 36 and the forward driven gear 38. The pair of idler gears 40 is supported by a floating idler gear mounting bracket 41 carrying pivot axles 43 about which the pair of idler gears 40 rotates. The forward driving gear 37 is rotatably fixed to the input driveshaft 18 and the forward driven gear 38 is rotatably fixed to the output driveshaft 24. Forward rotation of the input driveshaft 18 causes forward rotation of the forward driving gear 36, which causes reverse rotation of the pair of idler gears 40, which causes forward rotation of the forward driven gear 38. Forward rotation of the forward driven gear 38 causes forward rotation of the output driveshaft 24. Forward rotation of the output driveshaft 24 causes forward rotation of the propulsor shaft 26 via the beveled gearset 31, which causes the propulsor 28 to rotate so that a forward thrust is imparted on the marine vessel.

(14) In the illustrated embodiment, a cone clutch 42 is operable to position the transmission 22 into and between the above-described forward gear in which forward rotation of the input driveshaft 18 causes forward rotation of the propulsor shaft 26, reverse gear in which forward rotation of the input driveshaft 18 causes reverse rotation of the propulsor shaft 26, and neutral in which forward rotation of the input driveshaft 18 does not cause forward or reverse rotation of the propulsor shaft 26. The type and configuration of clutch can vary from that which is shown. In the illustrated example, the cone clutch 42 has a central cone 44 that is coupled to the input driveshaft 18, for example via helical or axial splines 45, so that rotation of the input driveshaft 18 causes rotation of the central cone 44 in each of the noted forward gear, reverse gear and neutral. The central cone 44 is axially movable, e.g., slideable, along the input driveshaft 18 into and between a reverse position (FIG. 7) in which the central cone 44 enacts the reverse gear, a forward position (FIG. 6) in which the central cone 44 enacts the forward gear, and a neutral position (FIG. 5), in which the central cone 44 enacts neutral. In other examples, the clutch can include a mechanical actuated wet plate clutch, an electro actuated wet plate clutch, a dog clutch, and/or the like.

(15) The cone clutch 42 includes a reverse cone 46 that is fixed to the reverse driving gear 32. When the transmission 20 is engaged in the noted reverse gear, the central cone 44 engages the reverse cone 46 so that rotation of the central cone 44 causes rotation of the reverse cone 46 and thus rotation of the reverse driving gear 32. The cone clutch 42 further includes a forward cone 48 that is fixed to the forward driving gear 36. When the transmission 20 is engaged in the noted forward gear, the central cone 44 engages the forward cone 48 so that rotation of the central cone 44 causes rotation of the forward cone 48 and thus rotation of the forward driving gear 36.

(16) A shift actuator 50 is configured to axially move the central cone 44 along the input driveshaft 18 so as to enact the noted reverse, neutral and forward gears. The shift actuator 50 includes a shift shaft 51 and a camming mechanism 52 that cams the shift shaft 51 up and down with respect to a shift shaft axis 54 upon rotation of the shift shaft 50 in opposite directions about the shift actuator axis 54. The camming mechanism 52 includes shifter plates 53, each having a contoured camming surface 55. Rotation of the shifter plates 53 with respect to the shift shaft axis 54 causes the contoured camming surfaces 55 to engage the reverse or forward cone 46, 48 and thus causes the camming mechanism 52 and shift shaft 51, to raise or lower depending on the direction of rotation. A shift fork 56 is sandwiched between the shifter plates 53 and travels with the shifter plates 53 along the shift shaft axis 54. The shift fork 56 connects the shift actuator 50 to the central cone 44 such that movement of the shift actuator 50 up and down causes commensurate movement of the central cone 44 up and down along the input driveshaft 18 into the reverse and forward gear positions described herein above.

(17) A detent mechanism 58 detents the shift actuator 50 in its neutral position along the shift actuator axis 54. The detent mechanism 58 includes a ball 59 that is biased into engagement with the shift shaft 51 by a spring 61 when the shift shaft 51 is located in neutral. Rotation of the shift shaft 51 about the shift shaft axis 54 causes the camming mechanism 52 to overcome the bias of the spring 61 and allows the shift shaft 51 to move out of the neutral position. Opposite rotation of the shift shaft 51 about the shift shaft axis 54 causes the camming mechanism 52 to bring the shift shaft 51 back into the neutral position wherein the spring 61 biases the ball 59 back into engagement with the shift shaft 51 to retain the shift shaft 51 in the neutral position.

(18) In operation, rotation of the shift shaft 51 rotates the camming mechanism 52, as described above, to thereby raise or lower the shift fork 56 depending on the direction of rotation. The shift fork 56 carries the cone clutch 42 up or down on the input driveshaft 18, to thereby enact the above-described reverse gear, forward gear, and neutral

(19) Referring to FIG. 8, a lubrication circuit 60 provides lubrication to the transmission 22. A lubrication pump 62 (for example a Gerotor) is coupled to the input driveshaft 18. Rotation of the input driveshaft 18 causes the lubrication pump 62 to pump the lubrication through the lubrication circuit 60. A lubrication reservoir 64 is located in the lower gearcase housing 14. The lubrication pump 62 draws lubrication from the lubrication reservoir 64 through a conduit 65 having a filtering screen, and pumps the lubrication to the transmission 22, specifically via axial channels 66 and a plurality of transverse openings 68 in the input driveshaft 18 and output driveshaft 24. Via the transverse openings 68, the lubrication is sprayed onto the surfaces of the cone clutch 42 requiring lubrication. The lubrication drains by gravity through the transmission 22, back to the lubrication reservoir 64. A replaceable filter 70 is disposed in the lubrication circuit 60. The lubrication pump 62 is configured to pump the lubrication through the replaceable filter 70 and then to the transmission 22 via the axial channels 66 and transverse openings 68. A spring-actuated bypass check valve 72 opens under pressure from the lubrication when the replaceable filter 70 becomes plugged and allows flow of lubrication to bypass the filter 70 on its way to the transmission 22.

(20) This written description uses examples to disclose embodiments of a marine propulsion device, including the best mode, and also to enable any person skilled in the art to make and use the same. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.