US20080014804A1 - Propulsion unit for marine drive - Google Patents
Propulsion unit for marine drive Download PDFInfo
- Publication number
- US20080014804A1 US20080014804A1 US11/771,780 US77178007A US2008014804A1 US 20080014804 A1 US20080014804 A1 US 20080014804A1 US 77178007 A US77178007 A US 77178007A US 2008014804 A1 US2008014804 A1 US 2008014804A1
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- United States
- Prior art keywords
- drive shaft
- bevel gear
- gear mechanism
- lubricant
- drive
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/04—Features relating to lubrication or cooling or heating
- F16H57/042—Guidance of lubricant
- F16H57/043—Guidance of lubricant within rotary parts, e.g. axial channels or radial openings in shafts
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63H—MARINE PROPULSION OR STEERING
- B63H20/00—Outboard propulsion units, e.g. outboard motors or Z-drives; Arrangements thereof on vessels
- B63H20/001—Arrangements, apparatus and methods for handling fluids used in outboard drives
- B63H20/002—Arrangements, apparatus and methods for handling fluids used in outboard drives for handling lubrication liquids
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/04—Features relating to lubrication or cooling or heating
- F16H57/0412—Cooling or heating; Control of temperature
- F16H57/0415—Air cooling or ventilation; Heat exchangers; Thermal insulations
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/04—Features relating to lubrication or cooling or heating
- F16H57/0434—Features relating to lubrication or cooling or heating relating to lubrication supply, e.g. pumps ; Pressure control
Definitions
- the present invention relates to a propulsion unit for a marine drive, and more specifically to a lubrication system in a lower casing of such a marine drive.
- the driving force from an engine is transmitted from a drive shaft to a propeller shaft via a bevel gear mechanism to produce propulsion force.
- a lower casing for holding the drive shaft, bevel gear mechanism and propeller shaft therein is subjected to a reaction force directly from water when the outboard motor is driven in water.
- the lateral width of the lower casing is typically kept very small. Accordingly, the bevel gear mechanism and the other parts described above are disposed in a limited space within the lower casing.
- the lower casing has lubricant filled therein.
- the lubricant is circulated in the lower casing to cool and lubricate such parts.
- the drive shaft has a spiral groove between upper and lower bearings.
- the spiral groove and the inner peripheral wall of a drive shaft hole in the lower casing form a slight gap therebetween to provide a screw pump.
- the screw pump delivers the lubricant upward from a bevel gear mechanism chamber to the upper and lower bearings. From the upper bearing, the lubricant is returned to the bevel gear mechanism chamber through another passage.
- the present invention provides a marine drive having an engine and a propulsion unit.
- the propulsion unit comprises a drive shaft driven by the engine, a bevel gear mechanism, a propeller shaft driven by the drive shaft via the bevel gear mechanism, and a lower casing adapted to support the propeller shaft, bevel gear mechanism, and drive shaft.
- the propeller shaft has a projection projecting generally rearward from the lower casing.
- a drive shaft bearing rotatably supports a journal of the drive shaft, and has a bevel gear mechanism attachment part.
- a lubricant circulating system is adapted to circulate lubricant between the bevel gear mechanism attachment part and the drive shaft bearing.
- the lubricant circulating system comprises a first lubricant passage extending in the lower casing from the bevel gear mechanism attachment part to the drive shaft bearing and a second lubricant passage defined in a gap between the drive shaft and an inner peripheral wall of a drive shaft chamber in the lower casing and extending from the drive shaft bearing to the bevel gear mechanism attachment part.
- the lubricant circulating system is configured so that lubricant flows from the bevel gear mechanism attachment part to the drive shaft bearing through the first passage, and from the drive shaft bearing to the bevel gear mechanism attachment part through the second passage.
- the bevel gear mechanism is adapted to function as a pump to urge lubricant into the first lubricant passage upon rotation of the drive shaft.
- the drive shaft has a spiral groove disposed in the periphery thereof the spiral groove delivering lubricant downward upon rotation of the drive shaft.
- the first lubricant passage is at least partially defined by a shift shaft chamber having a shift shaft disposed therein, the shift shaft selectively setting the bevel gear mechanism to a forward drive mode or a reverse drive mode.
- the marine drive comprises an outboard motor.
- the present invention provides a propulsion unit for a marine drive.
- the propulsion unit comprises a drive shaft adapted to be driven by an engine of the marine drive, a bevel gear mechanism chamber enclosing a bevel gear mechanism that connects to a lower portion of the drive shaft and is driven by the drive shaft, a propeller shaft having a forward portion that is connected to the bevel gear mechanism and is driven by the drive shaft via the bevel gear mechanism, a lower casing comprising the bevel gear mechanism chamber, a drive shaft journal bearing disposed above the bevel gear mechanism chamber for rotatably supporting the drive shaft, and a lubricant circulation system adapted to circulate lubricant between the bevel gear mechanism chamber and the drive shaft journal bearing.
- the lubricant circulation system comprises a lirst passage extending generally upwardly from the bevel gear mechanism chamber to the drive shaft journal bearing and a second passage defined in a gap between the drive shaft and an inner peripheral wall of a drive shaft chamber in the lower casing and extending from the drive shaft journal bearing to the bevel gear mechanism chamber.
- the lubricant circulation system is configured so that lubricant flows from the bevel gear mechanism chamber into the first passage to the drive shaft journal bearing and then through the second passage back to the bevel gear mechanism chamber.
- FIG. 1 is a side view of an outboard motor in accordance with an embodiment.
- FIG. 2 is a side view of a lower casing with a propulsion unit disposed therein for the outboard motor shown in FIG. 1 .
- FIG. 3 is a cross sectional view of the lower casing shown in FIG. 2 .
- FIG. 4 is a sectional plan view of the lower casing shown in FIG. 2 .
- FIG. 5 illustrates a forward bevel gear of the propulsion unit shown in FIG. 2 .
- FIG. 6 is a cross sectional view of the forward bevel gear shown in FIG. 5 .
- FIGS. 1 to 6 illustrate a propulsion unit for an outboard motor in accordance with an embodiment.
- FIG. 1 is a side view of an outboard motor on a hull;
- FIGS. 2 and 3 are respectively a side view and a cross sectional view of a lower casing having a propulsion unit disposed therein;
- FIG. 4 is a sectional plan view of a lower casing;
- FIGS. 5 and 6 are respectively a front view and a cross sectional view of a forward bevel gear of a bevel gear mechanism.
- This embodiment shows one example illustrating inventive principles. It is to be understood that the principles discussed herein can be employed in outboard motors having other structural configurations and in other marine drive configurations, such as stern drives.
- an outboard motor 1 is mounted at the stern 2 a of a hull 2 .
- the outboard motor 1 has a clamp bracket 3 secured to the stern 2 a and includes a swivel arm 4 and a pivot shaft 5 .
- the swivel arm 4 supports the outboard motor 1 for up-and-down pivotal movement.
- the pivot shaft 5 supports the outboard motor 1 in a manner to steer to the left and right.
- the external structure of the outboard motor 1 generally includes a lower casing 7 , an upper casing 8 , and a cowling 11 .
- the lower casing 7 has a propulsion unit 6 enclosed therein.
- the upper casing 8 is coupled to the top of the lower casing 7 .
- On the top of the upper casing 8 an engine 10 is mounted.
- the cowling 11 is attached so as to surround the engine 10 .
- the engine 10 is positioned vertically such that the crankshaft 10 a is oriented generally vertically when the watercraft is driven on water.
- the propulsion unit 6 includes a drive shaft 12 , a propeller shaft 14 , the above-described lower casing 7 , and a propeller 15 .
- the drive shaft 12 is coaxially coupled to the crankshaft 10 a and is rotationally driven by the engine 10 .
- the propeller shaft 14 is positioned generally horizontally to be perpendicular to the drive shaft 12 , and is rotationally driven thereby via a bevel gear mechanism 13 .
- the lower casing 7 preferably holds therein the propeller shaft 14 and the drive shaft 12 .
- the propeller 15 is attached to a projection 14 a of the propeller shaft 14 that projects rearward from the lower casing 7 .
- the bevel gear mechanism 13 includes a drive bevel gear 17 , a forward bevel gear 18 , and a reverse bevel gear 19 .
- the drive bevel gear 17 is attached to a lower end 12 a (bevel gear mechanism attachment part) of the drive shaft 12 for rotation therewith.
- the forward bevel gear 18 and the reverse bevel gear 19 are in constant mesh with the drive bevel gear 17 , and are attached to a front end 14 b (bevel gear mechanism attachment part) of the propeller shaft 14 for rotation relative thereto.
- the forward bevel gear 18 preferably has a structure of a spiral bevel gear. As shown in FIGS. 5 and 6 , the illustrated forward bevel gear 18 is made up of a shaft portion 18 b and a bevel portion 18 c , and is formed as an integral piece.
- the shaft portion 18 b has a shaft bore 18 a disposed therein to receive the propeller shaft 14 .
- the bevel portion 18 c has a number of curved teeth 18 d disposed circumferentially thereon at a certain pitch.
- Each curved tooth 18 d curves in the forward rotational direction A of the forward bevel gear 18 as it extends from an inner end 18 d ′ to an outer end 18 d ′′. Accordingly, the pitch between the two adjacent curved teeth 18 d will become larger moving from w 2 at the inside end toward w 1 at the outside end.
- the drive bevel gear 17 and the reverse bevel gear 19 also have a spiral bevel gear structure comparable with the forward bevel gear 18 .
- the bevel gear mechanism 13 produces a lubricant stirring effect with the rotation of the drive shaft 12 , and acts as a gear pump to deliver lubricant that is in a bevel gear mechanism chamber 7 b (to be described later) into a shift shaft chamber 7 c.
- the illustrated bevel gear mechanism 13 includes a forward-reverse switching mechanism 20 .
- the forward-reverse switching mechanism 20 includes a dog clutch 21 , a shift sleeve 22 , a shift shaft 24 , and a shift lever (not shown).
- the dog clutch 21 is positioned between the forward and reverse bevel gears 18 , 19 on the propeller shaft 14 , and spline fitted over the propeller shaft 14 to move axially therealong and to rotate together therewith.
- the shift sleeve 22 is axially slidably inserted into the front end 14 b of the propeller shaft 14 .
- the shift shaft 24 is coupled to the shift sleeve 22 via a shift cam 23 .
- the shift lever (not shown) is coupled to the shift shaft 24 and positioned on the hull 2 .
- the dog clutch 21 selectively engages with the forward or reverse bevel gear 18 , 19 as it moves back and forth on the propeller shaft 14 .
- the shift sleeve 22 is coupled to the dog clutch 21 with a pin 25 .
- the pin 25 is disposed through a pin hole 14 e formed in the propeller shaft 14 between the forward and reverse bevel gears 18 , 19 .
- the dog clutch 21 is movable between a neutral position and forward and reverse clutch-in positions. In the neutral position, the dog clutch does not engage with the forward bevel gear 18 nor the reverse bevel gear 19 . In the forward and reverse clutch-in positions, the dog clutch engages with the forward or reverse bevel gear 18 , 19 .
- the shift shaft 24 will rotate to cause the shift cam 23 to convert the rotation of the shift shaft 24 to the axial movement of the shift sleeve 22 . Accordingly, the dog clutch 21 will be brought into engagement with the forward or reverse bevel gear 18 , 19 . As a result, the rotational force of the drive shaft 12 will be transmitted to the propeller shaft 14 .
- the lower casing 7 is generally bullet-shaped as viewed in a cross sectional view perpendicular to the drive shaft 12 .
- a drive shaft chamber 7 a is defined which extends generally vertically and is open upward.
- the drive shaft 12 is enclosed.
- the lower casing 7 preferably also has a bevel gear mechanism chamber 7 b defined therein which is positioned at the lower end of the drive shaft chamber 7 a .
- the bevel gear mechanism chamber 7 b extends in the fore-and-aft direction and is open rearward. In the bevel gear mechanism chamber 7 b , the bevel gear mechanism 13 is enclosed.
- a cylindrical bearing housing 30 is mounted within an upper end opening of the drive shaft chamber 7 a to establish a seal between the drive shaft 12 and the inner peripheral wall of the drive shaft chamber 7 a .
- the bearing housing 30 there are disposed a pair of upper and lower seals 31 , 31 for sealing between the housing 30 and the drive shaft 12 to prevent lubricant from flowing therethrough.
- An upper end 12 b of the drive shaft 12 in the illustrated lower casing 7 is rotatably supported by the housing 30 via a needle bearing 32 .
- a lower end 12 a of the drive shaft 12 is rotatably supported by a needle bearing 33 disposed within a lower end opening of the drive shaft chamber 7 a.
- a conical roller bearing 35 is disposed for rotatably supporting the forward bevel gear 18 .
- a ball bearing 37 is disposed for rotatably supporting the reverse bevel gear 19 via a gear housing 36 (to be described later).
- the illustrated lower casing 7 also has a shift shaft chamber 7 c defined therein.
- the shift shaft chamber 7 c is positioned in front of the drive shaft chamber 7 a and extends parallel to the drive shaft chamber 7 a .
- the shift shaft 24 is enclosed in the shift shaft chamber 7 c .
- a flange 24 a is formed at a lower end of the shift shaft 24 .
- the flange 24 a supports the shift shaft 24 in sliding contact with the inner periphery of the shift shaft chamber 7 c .
- the flange 24 a has an oil passage groove 24 b disposed therethrough.
- a lower end of the shift shaft chamber 7 c communicates with the bevel gear mechanism chamber 7 b .
- a seal 38 is mounted within an upper end opening of the shift shaft chamber 7 c to seal between the shift shaft 24 and the inner peripheral wall of the shift shaft chamber 7 c.
- the illustrated lower casing 7 has a cooling water intake passage 7 d defined therein.
- the cooling water intake passage 7 d is positioned in front of the shift shaft chamber 7 c and extends parallel to the shift shaft chamber 7 c .
- the cooling water intake passage 7 d is designed to make cooling water flow therethrough which enters through inlets 7 g formed in left and right sidewalls of the lower casing 7 .
- the illustrated lower casing 7 has a cooling water jacket 7 h defined therein which surrounds the drive shaft chamber 7 a .
- the cooling water flowing through the cooling jacket 7 h cools the lubricant in the drive shaft chamber 7 a .
- the lubricant in the shift shaft chamber 7 c is also cooled by the cooling water flowing through the cooling water intake passage 7 d and the cooling water jacket 7 h.
- the illustrated lower casing 7 also has an exhaust gas passage 7 e defined therein which is positioned behind the drive shaft chamber 7 a .
- the cooling water jacket 7 h is positioned between the exhaust gas passage 7 e and the drive shaft chamber 7 a .
- the exhaust gas passage 7 e communicates with a discharge opening (not shown) formed in the rear end face of the lower casing 7 . Exhaust gas from the engine 10 will flow through the upper casing 7 and through the passage 7 c to be discharged through the discharge opening into water.
- the gear housing 36 described above is inserted so as to extend across the exhaust gas passage 7 e .
- the gear housing 36 defines the exhaust gas passage 7 e and the bevel gear mechanism chamber 7 b.
- the illustrated gear housing 36 includes a cylindrical portion 36 b , a large-diameter portion 36 c , a plurality of ribs 36 d , and a flange 36 e .
- the cylindrical portion 36 b has a propeller shaft bore 36 a disposed therethrough.
- the large-diameter portion 36 c is cup-shaped and is formed at a front end of the cylindrical portion 36 b .
- the ribs 36 d are formed at a rear end of the cylindrical portion 36 b to extend radially outward perpendicularly to the axial direction thereof.
- the flange 36 e is formed on peripheral ends of the ribs 36 d .
- the flange 36 e is secured to the peripheral edge of the discharge opening in the lower casing 7 with a plurality of bolts 40 inserted from behind.
- the outer periphery of the large-diameter portion 36 c preferably is mounted within the rear end opening of the bevel gear mechanism chamber.
- the ball bearing 37 is mounted between the inner periphery of the large-diameter portion 36 c and a boss of the reverse bevel gear 19 .
- the propeller shaft 14 is disposed through the propeller shaft bore 36 a of the gear housing 36 .
- the front end 14 b of the propeller shaft 14 is inserted through a shaft bore 19 a of the reverse bevel gear 19 and into the shaft bore 18 a of the forward bevel gear 18 .
- the front end 14 b preferably is supported by the forward and reverse bevel gears 18 , 19 for rotation relative thereto, via a metal bearing 42 which is disposed within the shaft bore 18 a of the forward bevel gear 18 .
- the propeller shaft 14 and the shaft bore 19 a of the reverse bevel gear 19 preferably form a gap therebetween.
- a pair of front and rear seals 44 , 44 for sealing between the propeller shaft 14 and the gear housing 36 .
- a needle bearing 43 preferably is disposed for rotatably supporting a rear end 14 d of the propeller shaft 14 .
- the illustrated propulsion unit 6 includes an oil circulating system 47 which circulates therein a first part “a” and a second part “b” of the lubricant filled in the lower casing 7 .
- the first part “a” and the second part “b” of the lubricant circulate through the drive shaft chamber 7 a , the bevel gear mechanism chamber 7 b , the shift shaft chamber 7 c , and the propeller shaft bore 36 a .
- the oil level of the lubricant is positioned at the upper needle bearing 32 in the drive shaft chamber 7 a .
- the oil level is also positioned at the same height in the shift shaft chamber 7 c.
- the oil circulating system 47 preferably includes a drive shaft circulating system 48 and a propeller shaft circulating system 49 .
- the drive shaft circulating system 48 circulates the first part “a” of the lubricant therein to flow from the bevel gear mechanism attachment part (lower end) 12 a of the drive shaft 12 to the forward-reverse switching mechanism 20 and then to the upper and lower needle bearings 32 , 33 .
- the propeller shaft circulating system 49 circulates the second part “b” of the lubricant therein to flow from the bevel gear mechanism attachment part (front end) 14 b of the propeller shaft 14 to the needle bearing 43 .
- the illustrated propeller shaft circulating system 49 includes an oil passage 49 c and a return passage 49 d .
- the oil passage 49 c includes an axial passage 49 a and a vertical passage 49 b .
- the axial passage 49 a is disposed in the propeller shaft 14 and extends axially therealong from the bevel gear mechanism attachment part 14 b to a position proximate to the needle bearing 43 .
- the vertical passage 49 b radially extends from an extended end of the axial passage 49 a and communicates with an area proximate to the needle bearing 43 .
- the return passage 49 d preferably is formed by a gap between the propeller shaft 14 and the inner peripheral wall of the propeller shaft bore 36 a of the gear housing 36 .
- the axial passage 49 a of the oil passage 49 c preferably communicates with the pin hole 14 e of the propeller shaft 14 .
- the vertical passage 49 b preferably communicates with the area proximate to a front part of the needle bearing 43 .
- the propeller shaft 14 will start rotation.
- the second part “b” of the lubricant will be forced out through the vertical passage 49 b of the oil passage 49 c by centrifugal force due to the rotation of the propeller shaft 14 .
- the forced-out second part “b” will lubricate the needle bearing 43 and then flow through the return passage 49 d to lubricate the ball bearing 37 and the meshing parts of the bevel gear mechanism 13 , and then return to the bevel gear mechanism chamber 7 b .
- the second part “b” of the lubricant in the bevel gear mechanism chamber 7 b will enter the axial passage 49 a of the oil passage 49 c by the rotation of the propeller shaft 14 .
- the illustrated drive shaft circulating system 48 includes the shift shaft chamber 7 c , an oil return passage 48 a , a screw pump 48 b , and a communication passage 48 c .
- the shift shaft chamber 7 c defines an oil passage for the drive shaft circulating system 48 .
- the oil return passage 48 a preferably is formed by a gap between the drive shaft 12 and the inner peripheral wall of the drive shaft chamber 7 a of the lower casing 7 , and extends axially along the drive shaft 12 .
- the screw pump 48 b is formed by an axial central portion of the drive shaft 12 in the lower casing 7 and the inner peripheral wall of the drive shaft chamber 7 a .
- the communication passage 48 c communicates the shift shaft chamber 7 c and a part of the return passage 48 a around the needle bearing 32 .
- the drive shaft 12 in the illustrated lower casing 7 has a spiral groove 12 c formed in the periphery thereof which extends downward in a clockwise direction.
- the screw pump 48 b is obtained by providing a slight gap between the spiral groove 12 c and the inner peripheral wall of the drive shaft chamber 7 a .
- the screw pump 48 b pressurizes and delivers downward the first part “a” of the lubricant in the oil passage 48 a.
- the screw pump 48 b will pressurize and help deliver the first part “a” of the lubricant downward through the oil passage 48 a .
- the bevel gear mechanism 13 will also rotate to thereby stir and deliver the first part “a” in the bevel gear mechanism chamber 7 b into the shift shaft chamber 7 c.
- the first part “a” of the lubricant that entered the shift shaft chamber 7 c due to the lubricant stirring effect of the bevel gear mechanism 13 will first lubricate the forward-reverse switching mechanism 20 and then flow through the oil passage groove 24 b and go upward through the shift shaft chamber 7 c . It will then flow from an upper end of the shift shaft chamber 7 c through the communication passage 48 c into the oil return passage 48 a . The first part “a” that entered the return passage 48 a will flow to and lubricate the upper needle bearing 32 of the drive shaft 12 .
- the first part “a” flowing through the shift shaft chamber 7 c and the drive shaft chamber 7 a will be cooled by the cooling water flowing through the cooling water intake passage 7 d and the cooling water jacket 7 h.
- the first part “a” of the lubricant in the drive shaft circulating system 48 is delivered from the bevel gear mechanism chamber 7 b into the shift shaft chamber 7 c due to the lubricant stirring effect of the bevel gear mechanism 13 .
- the first part “a” flows from the shift shaft chamber 7 c through the communication passage 48 c into the oil return passage 48 a to lubricate the needle bearing 32 of the drive shaft 12 .
- the first part “a” that lubricated the bearing 32 is then delivered downward by the screw pump 48 b through the return passage 48 a to return to the bevel gear mechanism chamber 7 b .
- the first part “a” of the lubricant can circulate in the direction in which the bevel gear mechanism 13 delivers the lubricant due to the lubricant stirring effect (direction of the arrow “a”). This prevents stagnation or backflow of the lubricant. Hence, less wear occurs to the meshing parts of the bevel gear mechanism 13 and the bearings of the drive shaft 12 , thereby assuring the prolonged life of the parts.
- the drive shaft 12 has the spiral groove 12 c formed in the periphery thereof which delivers the first part “a” of the lubricant downward. Accordingly, the drive shaft 12 acts as a screw pump to deliver the first part “a” in the same direction as the direction in which the bevel gear mechanism 13 delivers the lubricant. This further facilitates the circulation of the first part “a”, thereby helping to maintain it at an appropriate temperature and helping promote prolonged life of the parts. Thus, the life of the parts can be prolonged further.
- the first part “a” is delivered from the bevel gear mechanism chamber 7 b into the shift shaft chamber 7 c by the bevel gear mechanism 13 . Since the bevel gear mechanism 13 acts as a gear pump, the circulation of the first part “a” is facilitated further.
- the lubricant stirring effect of the bevel gear mechanism 13 is utilized to make the first part “a” flow from the shift shaft chamber 7 c to the drive shaft chamber 7 a . Accordingly, the direction in which the bevel gear mechanism 13 delivers the lubricant coincides with the direction in which the screw pump 48 b delivers the lubricant. This further prevents stagnation or backflow of the lubricant.
- the shift shaft chamber 7 c is used as an oil passage. Accordingly, the oil circulating system can be formed by utilizing the existing shift shaft chamber 7 c . This prevents the lower casing 7 from increasing in size and effects cost reduction.
- the shift shaft chamber 7 c which is used as an oil passage, preferably is surrounded by the cooling water intake passage 7 d and the cooling jacket 7 h and is disposed apart from the exhaust gas passage 7 e . This provides enhanced cooling characteristics of the first part “a” of the lubricant flowing through the shift shaft chamber 7 c.
- the shift shaft chamber 7 c is used as the oil passage, but the oil passage may be provided separately from the shift shaft chamber.
- bearings and gears having other structure and being used in other types of marine drives such as stern drives or outboard motors having different structure such as having only a forward gear, or other structures and configurations, can employ inventive aspects.
- the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the claims that follow.
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- General Engineering & Computer Science (AREA)
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- Ocean & Marine Engineering (AREA)
- General Details Of Gearings (AREA)
Abstract
A marine propulsion unit having an oil circulation system is provided. In the oil circulation system, lubricant is delivered from a bevel gear mechanism adjacent a drive shaft through an oil passage defined in a lower casing to a journal bearing supporting the drive shaft. From the drive shaft journal bearing, the lubricant flows through a gap between the drive shaft and the inner peripheral wall of a drive shaft chamber in the lower casing and then returns to the bevel gear mechanism.
Description
- The present application is based on and claims priority under 35 U.S.C. § 119 to Japanese Patent Application Serial No. 2006-193213, filed on Jul. 13, 2006, the entire contents of which are expressly incorporated by reference herein.
- 1. Field of the Invention
- The present invention relates to a propulsion unit for a marine drive, and more specifically to a lubrication system in a lower casing of such a marine drive.
- 2. Description of Related Art
- In marine drives such as outboard motors designed for small watercrafts or the like, the driving force from an engine is transmitted from a drive shaft to a propeller shaft via a bevel gear mechanism to produce propulsion force.
- In this type of outboard motor, a lower casing for holding the drive shaft, bevel gear mechanism and propeller shaft therein is subjected to a reaction force directly from water when the outboard motor is driven in water. Thus, the lateral width of the lower casing is typically kept very small. Accordingly, the bevel gear mechanism and the other parts described above are disposed in a limited space within the lower casing.
- To prolong the life of bearings of the drive shaft and meshing parts of the bevel gear mechanism, the lower casing has lubricant filled therein. The lubricant is circulated in the lower casing to cool and lubricate such parts.
- According to Japanese Patent Document JP-A-Sho 57-182595, for example, the drive shaft has a spiral groove between upper and lower bearings. The spiral groove and the inner peripheral wall of a drive shaft hole in the lower casing form a slight gap therebetween to provide a screw pump. The screw pump delivers the lubricant upward from a bevel gear mechanism chamber to the upper and lower bearings. From the upper bearing, the lubricant is returned to the bevel gear mechanism chamber through another passage.
- Applicant has noted, however, that in motors as just described, the lubricant may stagnate or flow back. As a result, the temperature of the lubricant may increase, resulting in wear of the meshing parts of the bevel gear mechanism and the bearings of the drive shaft. The life of the parts may therefore be shortened.
- Accordingly, there is a need in the art for a propulsion unit for an outboard motor in which stagnation or backflow of lubricant is prevented, therefore improving lubricant circulation and prolonging the life of meshing parts of a bevel gear mechanism and bearings of a drive shaft.
- Through study, experimentation, and analysis, Applicant has discovered that as the drive shaft rotates, the bevel gear mechanism rotates to thereby produce a lubricant stirring effect. This effect causes the lubricant to be delivered in a direction opposite to the intended direction of the lubricant flow through the above-described oil circulating channel, or the direction in which the screw pump delivers the lubricant. Applicant thus determined that the stirring effect causes the stagnation or backflow of lubricant. In light of his discovery, Applicant invented principles and structure for constructing a lubricant circulation system that uses the oil stirring effect to aid lubricant circulation, and thus prevent stagnation or backflow of lubricant.
- In accordance with one embodiment, the present invention provides a marine drive having an engine and a propulsion unit. The propulsion unit comprises a drive shaft driven by the engine, a bevel gear mechanism, a propeller shaft driven by the drive shaft via the bevel gear mechanism, and a lower casing adapted to support the propeller shaft, bevel gear mechanism, and drive shaft. The propeller shaft has a projection projecting generally rearward from the lower casing. A drive shaft bearing rotatably supports a journal of the drive shaft, and has a bevel gear mechanism attachment part. A lubricant circulating system is adapted to circulate lubricant between the bevel gear mechanism attachment part and the drive shaft bearing. The lubricant circulating system comprises a first lubricant passage extending in the lower casing from the bevel gear mechanism attachment part to the drive shaft bearing and a second lubricant passage defined in a gap between the drive shaft and an inner peripheral wall of a drive shaft chamber in the lower casing and extending from the drive shaft bearing to the bevel gear mechanism attachment part. The lubricant circulating system is configured so that lubricant flows from the bevel gear mechanism attachment part to the drive shaft bearing through the first passage, and from the drive shaft bearing to the bevel gear mechanism attachment part through the second passage.
- In one such embodiment the bevel gear mechanism is adapted to function as a pump to urge lubricant into the first lubricant passage upon rotation of the drive shaft. In another embodiment the drive shaft has a spiral groove disposed in the periphery thereof the spiral groove delivering lubricant downward upon rotation of the drive shaft. In still another embodiment the first lubricant passage is at least partially defined by a shift shaft chamber having a shift shaft disposed therein, the shift shaft selectively setting the bevel gear mechanism to a forward drive mode or a reverse drive mode.
- In another embodiment the marine drive comprises an outboard motor.
- In accordance with another embodiment, the present invention provides a propulsion unit for a marine drive. The propulsion unit comprises a drive shaft adapted to be driven by an engine of the marine drive, a bevel gear mechanism chamber enclosing a bevel gear mechanism that connects to a lower portion of the drive shaft and is driven by the drive shaft, a propeller shaft having a forward portion that is connected to the bevel gear mechanism and is driven by the drive shaft via the bevel gear mechanism, a lower casing comprising the bevel gear mechanism chamber, a drive shaft journal bearing disposed above the bevel gear mechanism chamber for rotatably supporting the drive shaft, and a lubricant circulation system adapted to circulate lubricant between the bevel gear mechanism chamber and the drive shaft journal bearing. The lubricant circulation system comprises a lirst passage extending generally upwardly from the bevel gear mechanism chamber to the drive shaft journal bearing and a second passage defined in a gap between the drive shaft and an inner peripheral wall of a drive shaft chamber in the lower casing and extending from the drive shaft journal bearing to the bevel gear mechanism chamber. The lubricant circulation system is configured so that lubricant flows from the bevel gear mechanism chamber into the first passage to the drive shaft journal bearing and then through the second passage back to the bevel gear mechanism chamber.
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FIG. 1 is a side view of an outboard motor in accordance with an embodiment. -
FIG. 2 is a side view of a lower casing with a propulsion unit disposed therein for the outboard motor shown inFIG. 1 . -
FIG. 3 is a cross sectional view of the lower casing shown inFIG. 2 . -
FIG. 4 is a sectional plan view of the lower casing shown inFIG. 2 . -
FIG. 5 illustrates a forward bevel gear of the propulsion unit shown inFIG. 2 . -
FIG. 6 is a cross sectional view of the forward bevel gear shown inFIG. 5 . - Embodiments of the present invention will be described hereinafter with reference to the accompanying drawings.
-
FIGS. 1 to 6 illustrate a propulsion unit for an outboard motor in accordance with an embodiment.FIG. 1 is a side view of an outboard motor on a hull;FIGS. 2 and 3 are respectively a side view and a cross sectional view of a lower casing having a propulsion unit disposed therein;FIG. 4 is a sectional plan view of a lower casing; andFIGS. 5 and 6 are respectively a front view and a cross sectional view of a forward bevel gear of a bevel gear mechanism. This embodiment shows one example illustrating inventive principles. It is to be understood that the principles discussed herein can be employed in outboard motors having other structural configurations and in other marine drive configurations, such as stern drives. - In the figures, an
outboard motor 1 is mounted at thestern 2 a of ahull 2. Theoutboard motor 1 has aclamp bracket 3 secured to thestern 2 a and includes a swivel arm 4 and a pivot shaft 5. The swivel arm 4 supports theoutboard motor 1 for up-and-down pivotal movement. The pivot shaft 5 supports theoutboard motor 1 in a manner to steer to the left and right. - The external structure of the
outboard motor 1 generally includes alower casing 7, anupper casing 8, and acowling 11. Thelower casing 7 has apropulsion unit 6 enclosed therein. Theupper casing 8 is coupled to the top of thelower casing 7. On the top of theupper casing 8, anengine 10 is mounted. Thecowling 11 is attached so as to surround theengine 10. Theengine 10 is positioned vertically such that thecrankshaft 10 a is oriented generally vertically when the watercraft is driven on water. - The
propulsion unit 6 includes adrive shaft 12, apropeller shaft 14, the above-describedlower casing 7, and apropeller 15. Thedrive shaft 12 is coaxially coupled to thecrankshaft 10 a and is rotationally driven by theengine 10. Thepropeller shaft 14 is positioned generally horizontally to be perpendicular to thedrive shaft 12, and is rotationally driven thereby via abevel gear mechanism 13. Thelower casing 7 preferably holds therein thepropeller shaft 14 and thedrive shaft 12. Thepropeller 15 is attached to aprojection 14 a of thepropeller shaft 14 that projects rearward from thelower casing 7. - The
bevel gear mechanism 13 includes adrive bevel gear 17, aforward bevel gear 18, and areverse bevel gear 19. Thedrive bevel gear 17 is attached to alower end 12 a (bevel gear mechanism attachment part) of thedrive shaft 12 for rotation therewith. Theforward bevel gear 18 and thereverse bevel gear 19 are in constant mesh with thedrive bevel gear 17, and are attached to afront end 14 b (bevel gear mechanism attachment part) of thepropeller shaft 14 for rotation relative thereto. - The
forward bevel gear 18 preferably has a structure of a spiral bevel gear. As shown inFIGS. 5 and 6 , the illustratedforward bevel gear 18 is made up of ashaft portion 18 b and abevel portion 18 c, and is formed as an integral piece. Theshaft portion 18 b has a shaft bore 18 a disposed therein to receive thepropeller shaft 14. Thebevel portion 18 c has a number ofcurved teeth 18 d disposed circumferentially thereon at a certain pitch. - Each
curved tooth 18 d curves in the forward rotational direction A of theforward bevel gear 18 as it extends from aninner end 18 d′ to anouter end 18 d″. Accordingly, the pitch between the two adjacentcurved teeth 18 d will become larger moving from w2 at the inside end toward w1 at the outside end. In the illustrated embodiment, thedrive bevel gear 17 and thereverse bevel gear 19 also have a spiral bevel gear structure comparable with theforward bevel gear 18. - As such, the
bevel gear mechanism 13 produces a lubricant stirring effect with the rotation of thedrive shaft 12, and acts as a gear pump to deliver lubricant that is in a bevelgear mechanism chamber 7 b (to be described later) into ashift shaft chamber 7 c. - The illustrated
bevel gear mechanism 13 includes a forward-reverse switching mechanism 20. The forward-reverse switching mechanism 20 includes adog clutch 21, ashift sleeve 22, ashift shaft 24, and a shift lever (not shown). Thedog clutch 21 is positioned between the forward andreverse bevel gears propeller shaft 14, and spline fitted over thepropeller shaft 14 to move axially therealong and to rotate together therewith. Theshift sleeve 22 is axially slidably inserted into thefront end 14 b of thepropeller shaft 14. Theshift shaft 24 is coupled to theshift sleeve 22 via ashift cam 23. The shift lever (not shown) is coupled to theshift shaft 24 and positioned on thehull 2. Thedog clutch 21 selectively engages with the forward or reversebevel gear propeller shaft 14. - The
shift sleeve 22 is coupled to thedog clutch 21 with apin 25. Thepin 25 is disposed through a pin hole 14 e formed in thepropeller shaft 14 between the forward andreverse bevel gears - The
dog clutch 21 is movable between a neutral position and forward and reverse clutch-in positions. In the neutral position, the dog clutch does not engage with theforward bevel gear 18 nor thereverse bevel gear 19. In the forward and reverse clutch-in positions, the dog clutch engages with the forward or reversebevel gear - As the operator operates the shift lever from the neutral position to the forward or reverse clutch-in position, the
shift shaft 24 will rotate to cause theshift cam 23 to convert the rotation of theshift shaft 24 to the axial movement of theshift sleeve 22. Accordingly, thedog clutch 21 will be brought into engagement with the forward or reversebevel gear drive shaft 12 will be transmitted to thepropeller shaft 14. - In the illustrated embodiment, the
lower casing 7 is generally bullet-shaped as viewed in a cross sectional view perpendicular to thedrive shaft 12. In thelower casing 7 at a generally central portion in the fore-and-aft direction, adrive shaft chamber 7 a is defined which extends generally vertically and is open upward. In thedrive shaft chamber 7 a, thedrive shaft 12 is enclosed. - The
lower casing 7 preferably also has a bevelgear mechanism chamber 7 b defined therein which is positioned at the lower end of thedrive shaft chamber 7 a. The bevelgear mechanism chamber 7 b extends in the fore-and-aft direction and is open rearward. In the bevelgear mechanism chamber 7 b, thebevel gear mechanism 13 is enclosed. - A cylindrical bearing
housing 30 is mounted within an upper end opening of thedrive shaft chamber 7 a to establish a seal between thedrive shaft 12 and the inner peripheral wall of thedrive shaft chamber 7 a. In the bearinghousing 30, there are disposed a pair of upper andlower seals housing 30 and thedrive shaft 12 to prevent lubricant from flowing therethrough. - An
upper end 12 b of thedrive shaft 12 in the illustratedlower casing 7 is rotatably supported by thehousing 30 via aneedle bearing 32. Alower end 12 a of thedrive shaft 12 is rotatably supported by aneedle bearing 33 disposed within a lower end opening of thedrive shaft chamber 7 a. - In the illustrated bevel
gear mechanism chamber 7 b at its front end, aconical roller bearing 35 is disposed for rotatably supporting theforward bevel gear 18. Within a rear end opening of the bevelgear mechanism chamber 7 b, aball bearing 37 is disposed for rotatably supporting thereverse bevel gear 19 via a gear housing 36 (to be described later). - The illustrated
lower casing 7 also has ashift shaft chamber 7 c defined therein. Theshift shaft chamber 7 c is positioned in front of thedrive shaft chamber 7 a and extends parallel to thedrive shaft chamber 7 a. In theshift shaft chamber 7 c, theshift shaft 24 is enclosed. Aflange 24 a is formed at a lower end of theshift shaft 24. Theflange 24 a supports theshift shaft 24 in sliding contact with the inner periphery of theshift shaft chamber 7 c. Theflange 24 a has anoil passage groove 24 b disposed therethrough. - A lower end of the
shift shaft chamber 7 c communicates with the bevelgear mechanism chamber 7 b. A seal 38 is mounted within an upper end opening of theshift shaft chamber 7 c to seal between theshift shaft 24 and the inner peripheral wall of theshift shaft chamber 7 c. - The illustrated
lower casing 7 has a coolingwater intake passage 7 d defined therein. The coolingwater intake passage 7 d is positioned in front of theshift shaft chamber 7 c and extends parallel to theshift shaft chamber 7 c. The coolingwater intake passage 7 d is designed to make cooling water flow therethrough which enters throughinlets 7 g formed in left and right sidewalls of thelower casing 7. - The illustrated
lower casing 7 has a coolingwater jacket 7 h defined therein which surrounds thedrive shaft chamber 7 a. The cooling water flowing through the coolingjacket 7 h cools the lubricant in thedrive shaft chamber 7 a. The lubricant in theshift shaft chamber 7 c is also cooled by the cooling water flowing through the coolingwater intake passage 7 d and the coolingwater jacket 7 h. - The illustrated
lower casing 7 also has anexhaust gas passage 7 e defined therein which is positioned behind thedrive shaft chamber 7 a. The coolingwater jacket 7 h is positioned between theexhaust gas passage 7 e and thedrive shaft chamber 7 a. Theexhaust gas passage 7 e communicates with a discharge opening (not shown) formed in the rear end face of thelower casing 7. Exhaust gas from theengine 10 will flow through theupper casing 7 and through thepassage 7 c to be discharged through the discharge opening into water. - In the bevel
gear mechanism chamber 7 b of the illustratedlower casing 7, thegear housing 36 described above is inserted so as to extend across theexhaust gas passage 7 e. Thegear housing 36 defines theexhaust gas passage 7 e and the bevelgear mechanism chamber 7 b. - The illustrated
gear housing 36 includes acylindrical portion 36 b, a large-diameter portion 36 c, a plurality ofribs 36 d, and aflange 36 e. Thecylindrical portion 36 b has a propeller shaft bore 36 a disposed therethrough. The large-diameter portion 36 c is cup-shaped and is formed at a front end of thecylindrical portion 36 b. Theribs 36 d are formed at a rear end of thecylindrical portion 36 b to extend radially outward perpendicularly to the axial direction thereof. Theflange 36 e is formed on peripheral ends of theribs 36 d. Theflange 36 e is secured to the peripheral edge of the discharge opening in thelower casing 7 with a plurality ofbolts 40 inserted from behind. - The outer periphery of the large-
diameter portion 36 c preferably is mounted within the rear end opening of the bevel gear mechanism chamber. Theball bearing 37 is mounted between the inner periphery of the large-diameter portion 36 c and a boss of thereverse bevel gear 19. - The
propeller shaft 14 is disposed through the propeller shaft bore 36 a of thegear housing 36. Thefront end 14 b of thepropeller shaft 14 is inserted through a shaft bore 19 a of thereverse bevel gear 19 and into the shaft bore 18 a of theforward bevel gear 18. Thefront end 14 b preferably is supported by the forward andreverse bevel gears forward bevel gear 18. Thepropeller shaft 14 and the shaft bore 19 a of thereverse bevel gear 19 preferably form a gap therebetween. - At a rear end of the propeller shaft bore 36 a of the illustrated
gear housing 36, there is disposed a pair of front andrear seals propeller shaft 14 and thegear housing 36. - In the propeller shaft bore 36 a of the
gear housing 36 and just in front of theseals 44, aneedle bearing 43 preferably is disposed for rotatably supporting a rear end 14 d of thepropeller shaft 14. - The illustrated
propulsion unit 6 includes anoil circulating system 47 which circulates therein a first part “a” and a second part “b” of the lubricant filled in thelower casing 7. In theoil circulating system 47, the first part “a” and the second part “b” of the lubricant circulate through thedrive shaft chamber 7 a, the bevelgear mechanism chamber 7 b, theshift shaft chamber 7 c, and the propeller shaft bore 36 a. The oil level of the lubricant is positioned at theupper needle bearing 32 in thedrive shaft chamber 7 a. The oil level is also positioned at the same height in theshift shaft chamber 7 c. - The
oil circulating system 47 preferably includes a driveshaft circulating system 48 and a propeller shaft circulating system 49. The driveshaft circulating system 48 circulates the first part “a” of the lubricant therein to flow from the bevel gear mechanism attachment part (lower end) 12 a of thedrive shaft 12 to the forward-reverse switching mechanism 20 and then to the upper andlower needle bearings propeller shaft 14 to theneedle bearing 43. - The illustrated propeller shaft circulating system 49 includes an
oil passage 49 c and areturn passage 49 d. Theoil passage 49 c includes anaxial passage 49 a and avertical passage 49 b. Theaxial passage 49 a is disposed in thepropeller shaft 14 and extends axially therealong from the bevel gearmechanism attachment part 14 b to a position proximate to theneedle bearing 43. Thevertical passage 49 b radially extends from an extended end of theaxial passage 49 a and communicates with an area proximate to theneedle bearing 43. Thereturn passage 49 d preferably is formed by a gap between thepropeller shaft 14 and the inner peripheral wall of the propeller shaft bore 36 a of thegear housing 36. - The
axial passage 49 a of theoil passage 49 c preferably communicates with the pin hole 14 e of thepropeller shaft 14. Thevertical passage 49 b preferably communicates with the area proximate to a front part of theneedle bearing 43. - As the
dog clutch 21 engages with the forward or reversebevel gear propeller shaft 14 will start rotation. At this time, the second part “b” of the lubricant will be forced out through thevertical passage 49 b of theoil passage 49 c by centrifugal force due to the rotation of thepropeller shaft 14. The forced-out second part “b” will lubricate theneedle bearing 43 and then flow through thereturn passage 49 d to lubricate theball bearing 37 and the meshing parts of thebevel gear mechanism 13, and then return to the bevelgear mechanism chamber 7 b. The second part “b” of the lubricant in the bevelgear mechanism chamber 7 b will enter theaxial passage 49 a of theoil passage 49 c by the rotation of thepropeller shaft 14. - The illustrated drive
shaft circulating system 48 includes theshift shaft chamber 7 c, anoil return passage 48 a, ascrew pump 48 b, and acommunication passage 48 c. Theshift shaft chamber 7 c defines an oil passage for the driveshaft circulating system 48. Theoil return passage 48 a preferably is formed by a gap between thedrive shaft 12 and the inner peripheral wall of thedrive shaft chamber 7 a of thelower casing 7, and extends axially along thedrive shaft 12. Thescrew pump 48 b is formed by an axial central portion of thedrive shaft 12 in thelower casing 7 and the inner peripheral wall of thedrive shaft chamber 7 a. Thecommunication passage 48 c communicates theshift shaft chamber 7 c and a part of thereturn passage 48 a around theneedle bearing 32. - The
drive shaft 12 in the illustratedlower casing 7 has aspiral groove 12 c formed in the periphery thereof which extends downward in a clockwise direction. Thescrew pump 48 b is obtained by providing a slight gap between thespiral groove 12 c and the inner peripheral wall of thedrive shaft chamber 7 a. Thescrew pump 48 b pressurizes and delivers downward the first part “a” of the lubricant in theoil passage 48 a. - As the
drive shaft 12 rotates, thescrew pump 48 b will pressurize and help deliver the first part “a” of the lubricant downward through theoil passage 48 a. Thebevel gear mechanism 13 will also rotate to thereby stir and deliver the first part “a” in the bevelgear mechanism chamber 7 b into theshift shaft chamber 7 c. - The first part “a” of the lubricant that entered the
shift shaft chamber 7 c due to the lubricant stirring effect of thebevel gear mechanism 13 will first lubricate the forward-reverse switching mechanism 20 and then flow through theoil passage groove 24 b and go upward through theshift shaft chamber 7 c. It will then flow from an upper end of theshift shaft chamber 7 c through thecommunication passage 48 c into theoil return passage 48 a. The first part “a” that entered thereturn passage 48 a will flow to and lubricate theupper needle bearing 32 of thedrive shaft 12. It will then be pressurized and delivered downward by thescrew pump 48 b to lubricate thelower needle bearing 33, the meshing parts of thebevel gear mechanism 13 and thebearings gear mechanism chamber 7 b. The first part “a” in the bevelgear mechanism chamber 7 b will be delivered again into theshift shaft chamber 7 c by thebevel gear mechanism 13. - In the illustrated embodiment, the first part “a” flowing through the
shift shaft chamber 7 c and thedrive shaft chamber 7 a will be cooled by the cooling water flowing through the coolingwater intake passage 7 d and the coolingwater jacket 7 h. - In this embodiment, the first part “a” of the lubricant in the drive
shaft circulating system 48 is delivered from the bevelgear mechanism chamber 7 b into theshift shaft chamber 7 c due to the lubricant stirring effect of thebevel gear mechanism 13. The first part “a” flows from theshift shaft chamber 7 c through thecommunication passage 48 c into theoil return passage 48 a to lubricate theneedle bearing 32 of thedrive shaft 12. The first part “a” that lubricated thebearing 32 is then delivered downward by thescrew pump 48 b through thereturn passage 48 a to return to the bevelgear mechanism chamber 7 b. Accordingly, the first part “a” of the lubricant can circulate in the direction in which thebevel gear mechanism 13 delivers the lubricant due to the lubricant stirring effect (direction of the arrow “a”). This prevents stagnation or backflow of the lubricant. Hence, less wear occurs to the meshing parts of thebevel gear mechanism 13 and the bearings of thedrive shaft 12, thereby assuring the prolonged life of the parts. - In this embodiment, the
drive shaft 12 has thespiral groove 12 c formed in the periphery thereof which delivers the first part “a” of the lubricant downward. Accordingly, thedrive shaft 12 acts as a screw pump to deliver the first part “a” in the same direction as the direction in which thebevel gear mechanism 13 delivers the lubricant. This further facilitates the circulation of the first part “a”, thereby helping to maintain it at an appropriate temperature and helping promote prolonged life of the parts. Thus, the life of the parts can be prolonged further. - In this embodiment, the first part “a” is delivered from the bevel
gear mechanism chamber 7 b into theshift shaft chamber 7 c by thebevel gear mechanism 13. Since thebevel gear mechanism 13 acts as a gear pump, the circulation of the first part “a” is facilitated further. - More specifically, the lubricant stirring effect of the
bevel gear mechanism 13 is utilized to make the first part “a” flow from theshift shaft chamber 7 c to thedrive shaft chamber 7 a. Accordingly, the direction in which thebevel gear mechanism 13 delivers the lubricant coincides with the direction in which thescrew pump 48 b delivers the lubricant. This further prevents stagnation or backflow of the lubricant. - In this embodiment, the
shift shaft chamber 7 c is used as an oil passage. Accordingly, the oil circulating system can be formed by utilizing the existingshift shaft chamber 7 c. This prevents thelower casing 7 from increasing in size and effects cost reduction. - The
shift shaft chamber 7 c, which is used as an oil passage, preferably is surrounded by the coolingwater intake passage 7 d and the coolingjacket 7 h and is disposed apart from theexhaust gas passage 7 e. This provides enhanced cooling characteristics of the first part “a” of the lubricant flowing through theshift shaft chamber 7 c. - It should be understood that in this embodiment, the
shift shaft chamber 7 c is used as the oil passage, but the oil passage may be provided separately from the shift shaft chamber. - Although this invention has been disclosed in the context of certain preferred embodiments and examples, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. In addition, while a number of variations of the invention have been shown and described in detail, other modifications, which are within the scope of this invention, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combinations or subcombinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the invention. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the disclosed invention. For example, bearings and gears having other structure, and being used in other types of marine drives such as stern drives or outboard motors having different structure such as having only a forward gear, or other structures and configurations, can employ inventive aspects. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the claims that follow.
Claims (11)
1. A marine drive having an engine and a propulsion unit, the propulsion unit comprising a drive shaft driven by the engine, a bevel gear mechanism, a propeller shaft driven by the drive shaft via the bevel gear mechanism, a lower casing adapted to support the propeller shaft, bevel gear mechanism, and drive shaft, the propeller shaft having a projection projecting generally rearward from the lower casing, a drive shaft bearing for rotatably supporting a journal of the drive shaft, the drive shaft having a bevel gear mechanism attachment part, and a lubricant circulating system adapted to circulate lubricant between the bevel gear mechanism attachment part and the drive shaft bearing, the lubricant circulating system comprising a first lubricant passage extending in the lower casing from the bevel gear mechanism attachment part to the drive shaft bearing and a second lubricant passage defined in a gap between the drive shaft and an inner peripheral wall of a drive shaft chamber in the lower casing and extending from the drive shaft bearing to the bevel gear mechanism attachment part, wherein the lubricant circulating system is configured so that lubricant flows from the bevel gear mechanism attachment part to the drive shaft bearing through the first passage, and from the drive shaft bearing to the bevel gear mechanism attachment part through the second passage.
2. A marine drive as in claim 1 , wherein the bevel gear mechanism is adapted to function as a pump to urge lubricant into the first lubricant passage upon rotation of the drive shaft.
3. A marine drive as in claim 2 , wherein the drive shaft has a spiral groove disposed in the periphery thereof, the spiral grove delivering lubricant downward upon rotation of the drive shaft.
4. A marine drive as in claim 2 , wherein the first lubricant passage is at least partially defined by a shift shaft chamber having a shift shaft disposed therein, the shift shaft selectively setting the bevel gear mechanism to a forward drive mode or a reverse drive mode.
5. A marine drive as in claim 2 , wherein the marine drive comprises an outboard motor.
6. A marine drive as in claim 1 , wherein the drive shaft has a spiral groove disposed in the periphery thereof, the spiral grove delivering lubricant downward upon rotation of the drive shaft.
7. A marine drive as in claim 6 , wherein the first lubricant passage is at least partially defined by a shift shaft chamber having a shift shaft disposed therein, the shift shaft selectively setting the bevel gear mechanism to a forward drive mode or a reverse drive mode.
8. A propulsion unit for a marine drive, comprising a drive shaft adapted to be driven by an engine of the marine drive, a bevel gear mechanism chamber enclosing a bevel gear mechanism that connects to a lower portion of the drive shaft and is driven by the drive shaft, a propeller shaft having a forward portion that is connected to the bevel gear mechanism and is driven by the drive shaft via the bevel gear mechanism, a lower casing comprising the bevel gear mechanism chamber, a drive shaft journal bearing disposed above the bevel gear mechanism chamber for rotatably supporting the drive shaft, and a lubricant circulation system adapted to circulate lubricant between the bevel gear mechanism chamber and the drive shaft journal bearing, the lubricant circulation system comprising a first passage extending generally upwardly from the bevel gear mechanism chamber to the drive shaft journal bearing and a second passage defined in a gap between the drive shaft and an inner peripheral wall of a drive shaft chamber in the lower casing and extending from the drive shaft journal bearing to the bevel gear mechanism chamber, wherein the lubricant circulation system is configured so that lubricant flows from the bevel gear mechanism chamber into the first passage to the drive shaft journal bearing and then through the second passage back to the bevel gear mechanism chamber.
9. A propulsion device as in claim 8 , wherein the bevel gear mechanism functions as a pump to urge lubricant into the first passage upon rotation of the drive shaft.
10. A propulsion device as in claim 9 , wherein the drive shaft has a spiral groove disposed in the periphery thereof, the spiral grove delivering lubricant downward upon rotation of the drive shaft.
11. A propulsion device as in claim 8 , wherein the first passage is at least partially defined by a shift shaft chamber having a shift shaft disposed therein, the shift shaft selectively setting the bevel gear mechanism to a forward drive mode or a reverse drive mode.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2006193213A JP2008018867A (en) | 2006-07-13 | 2006-07-13 | Propulsion device of outboard motor |
JP2006-193213 | 2006-07-13 |
Publications (1)
Publication Number | Publication Date |
---|---|
US20080014804A1 true US20080014804A1 (en) | 2008-01-17 |
Family
ID=38949813
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/771,780 Abandoned US20080014804A1 (en) | 2006-07-13 | 2007-06-29 | Propulsion unit for marine drive |
Country Status (2)
Country | Link |
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US (1) | US20080014804A1 (en) |
JP (1) | JP2008018867A (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20160350753A1 (en) * | 2013-07-02 | 2016-12-01 | Mastercard International Incorporated | Unpredictable number generation |
US9656734B1 (en) | 2015-11-12 | 2017-05-23 | Yamaha Hatsudoki Kabushiki Kaisha | Outboard motor |
US10295046B2 (en) | 2017-04-21 | 2019-05-21 | Yamaha Hatsudoki Kabushiki Kaisha | Outboard motor |
US10428928B2 (en) * | 2017-03-24 | 2019-10-01 | Hamilton Sundstrand Corporation | Lubrication system for high speed gearbox operating in zero gravity |
US20210188413A1 (en) * | 2019-12-20 | 2021-06-24 | Suzuki Motor Corporation | Outboard motor |
CN117366201A (en) * | 2023-12-06 | 2024-01-09 | 智道铁路设备有限公司 | Gear box and gear clearance adjusting and measuring device thereof |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5248999B2 (en) * | 2008-11-21 | 2013-07-31 | ヤマハ発動機株式会社 | Marine propulsion unit |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5643025A (en) * | 1995-01-31 | 1997-07-01 | Sanshin Kogyo Kabushiki Kaisha | Transmission lubrication system |
US5697821A (en) * | 1993-11-29 | 1997-12-16 | Sanshin Kogyo Kabushiki Kaisha | Bearing carrier for outboard drive |
-
2006
- 2006-07-13 JP JP2006193213A patent/JP2008018867A/en not_active Withdrawn
-
2007
- 2007-06-29 US US11/771,780 patent/US20080014804A1/en not_active Abandoned
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5697821A (en) * | 1993-11-29 | 1997-12-16 | Sanshin Kogyo Kabushiki Kaisha | Bearing carrier for outboard drive |
US5643025A (en) * | 1995-01-31 | 1997-07-01 | Sanshin Kogyo Kabushiki Kaisha | Transmission lubrication system |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20160350753A1 (en) * | 2013-07-02 | 2016-12-01 | Mastercard International Incorporated | Unpredictable number generation |
US9656734B1 (en) | 2015-11-12 | 2017-05-23 | Yamaha Hatsudoki Kabushiki Kaisha | Outboard motor |
US10428928B2 (en) * | 2017-03-24 | 2019-10-01 | Hamilton Sundstrand Corporation | Lubrication system for high speed gearbox operating in zero gravity |
US10295046B2 (en) | 2017-04-21 | 2019-05-21 | Yamaha Hatsudoki Kabushiki Kaisha | Outboard motor |
US20210188413A1 (en) * | 2019-12-20 | 2021-06-24 | Suzuki Motor Corporation | Outboard motor |
US11772767B2 (en) * | 2019-12-20 | 2023-10-03 | Suzuki Motor Corporation | Outboard motor |
CN117366201A (en) * | 2023-12-06 | 2024-01-09 | 智道铁路设备有限公司 | Gear box and gear clearance adjusting and measuring device thereof |
Also Published As
Publication number | Publication date |
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JP2008018867A (en) | 2008-01-31 |
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