US20180086428A1 - Reverse gear - Google Patents
Reverse gear Download PDFInfo
- Publication number
- US20180086428A1 US20180086428A1 US15/715,667 US201715715667A US2018086428A1 US 20180086428 A1 US20180086428 A1 US 20180086428A1 US 201715715667 A US201715715667 A US 201715715667A US 2018086428 A1 US2018086428 A1 US 2018086428A1
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- United States
- Prior art keywords
- reverse
- gear
- reduction
- shaft
- clutch
- 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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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63H—MARINE PROPULSION OR STEERING
- B63H23/00—Transmitting power from propulsion power plant to propulsive elements
- B63H23/30—Transmitting power from propulsion power plant to propulsive elements characterised by use of clutches
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63H—MARINE PROPULSION OR STEERING
- B63H21/00—Use of propulsion power plant or units on vessels
- B63H21/21—Control means for engine or transmission, specially adapted for use on marine vessels
- B63H21/213—Levers or the like for controlling the engine or the transmission, e.g. single hand control levers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63H—MARINE PROPULSION OR STEERING
- B63H23/00—Transmitting power from propulsion power plant to propulsive elements
- B63H23/02—Transmitting power from propulsion power plant to propulsive elements with mechanical gearing
- B63H23/08—Transmitting power from propulsion power plant to propulsive elements with mechanical gearing with provision for reversing drive
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63H—MARINE PROPULSION OR STEERING
- B63H23/00—Transmitting power from propulsion power plant to propulsive elements
- B63H23/30—Transmitting power from propulsion power plant to propulsive elements characterised by use of clutches
- B63H2023/305—Transmitting power from propulsion power plant to propulsive elements characterised by use of clutches using fluid or semifluid as power transmitting means
Definitions
- the present invention relates to reverse gears for watercrafts that transmit rotational power of a main engine to a propeller.
- the present invention also relates to watercrafts equipped with such a reverse gear.
- Japanese Unexamined Patent Application Publication No. 7-17486 and Japanese Unexamined Utility Model Application Publication No. 6-78637 disclose reverse gears (marine gears) for watercrafts such as ski boats and pleasure boats.
- a reverse gear includes a forward clutch and a reverse clutch, which shift rotational power of an engine among forward rotation, neutral, and reverse rotation, and a reduction mechanism, which reduces the rotational power transmitted via the forward clutch or the reverse clutch and transmits the reduced rotational power to a propeller shaft.
- a reverse gear includes an input shaft, a forward/reverse switching mechanism, an output shaft, a reduction mechanism, a forward/reverse housing, and a reduction housing.
- the input shaft is configured to receive rotational power of a main engine.
- the forward/reverse switching mechanism includes a reduction function and is configured to switch the rotational power of the input shaft among forward, neutral, and reverse states.
- the output shaft is configured to output the rotational power of the forward/reverse switching mechanism and to rotate at a rotational speed that differs from a rotational speed of the input shaft due to the reduction function of the forward/reverse switching mechanism.
- the reduction mechanism includes a fixed reduction ratio and is configured to reduce the rotational power of the output shaft and to transmit the reduced rotational power to a propeller shaft.
- the forward/reverse housing accommodates the forward/reverse switching mechanism.
- the reduction housing accommodates the reduction mechanism.
- the forward/reverse housing and the reduction housing are detachably coupled one behind the other in an axial direction of the output shaft.
- the forward/reverse switching mechanism may include at least one of an input gear group and an output gear group.
- the input gear group and the output gear group may each include a plurality of gears engaged with one another.
- the forward/reverse switching mechanism may include a reduction ratio that is changed by replacing at least one of the input gear group and the output gear group.
- the forward/reverse switching mechanism may include a forward clutch and a reverse clutch that differ in a clutch size from each other.
- a reverse gear includes an input shaft, a forward/reverse switching mechanism, an output shaft, a reduction mechanism, a forward/reverse housing, and a reduction housing.
- the input shaft is configured to receive rotational power of a main engine.
- the forward/reverse switching mechanism includes a reduction function and is configured to switch the rotational power of the input shaft among forward, neutral, and reverse states.
- the output shaft is configured to output the rotational power of the forward/reverse switching mechanism and to rotate at a rotational speed that differs from a rotational speed of the input shaft due to the reduction function of the forward/reverse switching mechanism.
- the reduction mechanism includes a fixed reduction ratio and is configured to reduce the rotational power of the output shaft and to transmit the reduced rotational power to a propeller shaft.
- the forward/reverse housing accommodates the forward/reverse switching mechanism.
- the reduction housing accommodates the reduction mechanism.
- the forward/reverse housing and the reduction housing are detachably coupled one behind the other in an axial direction of the output shaft.
- the reduction mechanism may have a common structure, and the forward/reverse switching mechanism may be changed with one that has a desired reduction ratio. That is, the reduction housing may be shared among different models and specifications, and the reverse gear may be easily applied to a plurality of models and specifications of the watercrafts only by developing variations of the forward/reverse housing. This eliminates the need for producing the reduction mechanism that differs depending on models and specifications and thus reduces the production costs of models and specifications as a whole.
- the reduction ratio of the reduction mechanism is fixed, the number of gears constituting the reduction mechanism is reduced to reduce the size of the reduction mechanism and the space occupied by the reduction mechanism. This consequently reduces the size of the entire reverse gear and the space occupied by the entire reverse gear.
- This configuration improves the versatility of the reverse gear and enables the reverse gear to be mounted on the watercraft that has a limited height.
- the forward/reverse switching mechanism may include at least one of an input gear group and an output gear group.
- the input gear group and the output gear group may each include a plurality of gears engaged with one another.
- the reduction ratio of the forward/reverse switching mechanism may be changed by replacing at least one of the input gear group and the output gear group.
- a plurality of reduction ratios can be selected by the combination of the forward/reverse switching mechanism and the reduction mechanism in the entire reverse gear.
- the forward/reverse switching mechanism may include a forward clutch and a reverse clutch that differ in a clutch size from each other.
- the clutch size of the reverse clutch compared with the clutch size of the forward clutch, the size of the forward/reverse switching mechanism and the space occupied by the forward/reverse switching mechanism are reduced. This consequently further reduces the size of the reverse gear and the space occupied by the reverse gear.
- the reverse gear according to the embodiment of the present invention that reduces the production costs of models and specifications as a whole is mounted on a hull. This reduces the costs of the reverse gear and consequently reduces the production costs of the entire watercraft.
- FIG. 1 is a schematic side view of a ski boat
- FIG. 2 is a side view of a reverse gear according to a first embodiment
- FIG. 3 is a plan view of the reverse gear according to the first embodiment
- FIG. 4 is a schematic front view of the reverse gear according to the first embodiment illustrating how the gears are engaged
- FIG. 5 is a single-line diagram of a power transmission system of the reverse gear according to the first embodiment
- FIG. 6 is a side view of a reverse gear according to a second embodiment
- FIG. 7 is a plan view of the reverse gear according to the second embodiment.
- FIG. 8 is a schematic front view of the reverse gear according to the second embodiment illustrating how the gears are engaged
- FIG. 9 is a side view of a reverse gear according to a third embodiment.
- FIG. 10 is a plan view of the reverse gear according to the third embodiment.
- FIG. 11 is a single-line diagram of a power transmission system of the reverse gear according to the third embodiment.
- FIG. 12 is a side view of a reverse gear according to a fourth embodiment
- FIG. 13 is a plan view of the reverse gear according to the fourth embodiment.
- FIG. 14 is a single-line diagram of a power transmission system of the reverse gear according to the fourth embodiment.
- FIG. 15 is a single-line diagram of a power transmission system of a reverse gear according to a fifth embodiment
- FIG. 16 is a single-line diagram of a power transmission system of a reverse gear according to a sixth embodiment
- FIG. 17 is a side view of a reverse gear according to a seventh embodiment.
- FIG. 18 is a plan view of the reverse gear according to the seventh embodiment.
- FIG. 19 is a single-line diagram of a power transmission system of the reverse gear according to the seventh embodiment.
- FIG. 20 is a side view of a reverse gear according to an eighth embodiment
- FIG. 21 is a single-line diagram of a power transmission system of the reverse gear according to the eighth embodiment.
- FIG. 22 is a side view of a reverse gear according to a reference example
- FIG. 23 is a plan view of the reverse gear according to the reference example.
- FIG. 24 is a schematic front view of the reverse gear of the reference example illustrating how the gears are engaged.
- FIG. 25 is a single-line diagram of a power transmission system of the reverse gear according to the reference example.
- FIGS. 1 to 8 when terms indicating a specific direction or a position (for example, “left and right” and “up and down”) are used as required, the bow of a watercraft will be referred to as the front, the stern of the watercraft will be referred to as the rear, and the front and rear are used as a reference.
- the watercraft is a ski boat 1 in this embodiment. The terms are used for convenience of the description and do not intend to limit the technical range of the present invention.
- the ski boat 1 includes a hull 2 , a cockpit 3 , a rudder 4 , and a propeller 5 .
- the cockpit 3 is located on the upper surface of the hull at the center.
- the rudder 4 is provided on the bottom of the hull 2 at the watercraft's stern.
- the propeller 5 is located in front of the rudder 4 on the bottom of the hull 2 at the watercraft's stern.
- a propeller shaft 6 is supported on the bottom of the hull 2 at the watercraft's stern. The propeller shaft 6 rotates the propeller 5 .
- the propeller 5 is secured to the projecting end of the propeller shaft 6 .
- a steering wheel, a forward/reverse manipulator, a dead-slow travel manipulator, and a speed manipulator are provided in the cockpit 3 .
- the steering wheel changes the traveling direction of the hull 2 to left and right by steering.
- the forward/reverse manipulator shifts the traveling direction of the hull 2 between forward and reverse.
- the forward/reverse manipulator is a forward/reverse lever.
- the dead-slow travel manipulator causes the hull 2 to travel at dead slow.
- the dead-slow travel manipulator is a trawling lever.
- the speed manipulator sets and maintains the output rotational speed of an internal-combustion engine 10 , which will be discussed below.
- the speed manipulator is a throttle lever.
- the manipulators are not limited to the levers, but may be in other forms such as dials.
- An occupant's space S is provided at the rear section of the cockpit 3 .
- a seat 7 is located in the occupant's space S.
- a main engine, that is, a drive source of the propeller 5 is the engine 10 .
- the engine 10 and a reverse gear 11 are provided on the inner bottom portion of the hull 2 at the watercraft's stern.
- the reverse gear 11 transmits the rotational power of the engine 10 to the propeller 5 .
- the rotational power transmitted to the propeller shaft 6 from the engine 10 via the reverse gear 11 drivingly rotates the propeller 5 .
- the reverse gear 11 of the embodiment is a V-drive system in which, as viewed from the side, the shaft angle of the propeller shaft 6 is set to an acute angle (the angle between an input shaft 13 (or an output shaft 16 ) and the propeller shaft 6 is set to an acute angle as viewed from the side).
- the reverse gear 11 is located in front of the engine 10 .
- FIGS. 2 to 5 illustrate the reverse gear 11 according to a first embodiment.
- the reverse gear 11 of the first embodiment includes the input shaft 13 , a forward/reverse switching mechanism 20 , the output shaft 16 , and a reduction mechanism 17 .
- the input shaft 13 is coupled to a flywheel 12 of the engine 10 .
- the forward/reverse switching mechanism 20 switches the rotational power of the input shaft 13 among forward, neutral, and reverse states.
- the output shaft 16 outputs the rotational power of the forward/reverse switching mechanism 20 .
- the reduction mechanism 17 reduces the rotational power of the output shaft 16 and transmits the reduced rotational power to the propeller shaft 6 .
- An outer case of the reverse gear 11 includes a clutch lid member 18 a , a hollow box-like forward/reverse housing 18 b , a hollow reduction housing 18 c , and a reduction lid member 18 d .
- the clutch lid member 18 a is located at the rear section.
- the hollow reduction housing 18 c is L-shaped as viewed from the side.
- the reduction lid member 18 d is located at the front section.
- the clutch lid member 18 a is detachably coupled to the rear surface of the forward/reverse housing 18 b with a plurality of bolts.
- the front surface of the forward/reverse housing 18 b is detachably coupled to the rear surface of the body portion of the reduction housing 18 c with a plurality of bolts.
- the front surface of the reduction housing 18 c is detachably coupled to the reduction lid member 18 d with a plurality of bolts.
- the forward/reverse housing 18 b accommodates, for example, the input shaft 13 , the upstream section of the output shaft 16 , and the forward/reverse switching mechanism 20 .
- the reduction housing 18 c accommodates the downstream section of the output shaft 16 , the reduction mechanism 17 , and the upstream section of the propeller shaft 6 .
- the input shaft 13 projects rearward from the rear surface of the clutch lid member 18 a .
- the propeller shaft 6 projects diagonally downward and rearward from the rear surface of a downwardly extending portion of the reduction housing 18 c and projects from the watercraft's bottom. The lower the height of the upper surfaces of the lid members 18 a and 18 d and the housings 18 b and 18 c , the more spacious the inside of the watercraft such as the occupant's space S in the watercraft (refer to FIG. 1 ).
- An input gear 13 a is fixed to the front end section of the input shaft 13 .
- the input gear 13 a is constantly engaged with an input relay gear 14 g .
- the input relay gear 14 g is fixed to the rear end section of a forward clutch shaft 14 f .
- the forward clutch shaft 14 f extends parallel to the input shaft 13 .
- a forward clutch 14 is located on the forward clutch shaft 14 f and includes steel plates 14 d and friction plates 14 e that are alternately arranged.
- the forward clutch 14 includes a forward case 14 a to which the steel plates 14 d are attached, a forward tube 14 b to which the friction plates 14 e are attached, and a forward clutch cylinder 14 c .
- the friction plates 14 e are capable of being brought into contact with the steel plates 14 d under pressure.
- the forward clutch cylinder 14 c generates contact pressure using hydraulic oil pressure.
- the forward case 14 a is fixed to the forward clutch shaft 14 f .
- the forward tube 14 b is loosely fitted to the forward clutch shaft 14 f to be rotational.
- the rear end section of the forward tube 14 b is inserted in the inner circumference of the forward case 14 a .
- a forward gear 42 is integrally formed with the outer circumference of the forward case 14 a .
- a forward reduction gear 43 is integrally formed at the front end section of the forward tube 14 b .
- the forward clutch shaft 14 f configures a support shaft of the forward clutch 14 .
- a hydraulic pump 19 is coupled to the front end section of the forward clutch shaft 14 f .
- the hydraulic pump 19 supplies hydraulic oil to the forward clutch 14 and a reverse clutch 15 .
- the reverse clutch 15 is located on a reverse clutch shaft 15 f .
- the reverse clutch shaft 15 f extends parallel to the input shaft 13 .
- the reverse clutch 15 includes steel plates 15 d and friction plates 15 e that are alternately arranged.
- the reverse clutch 15 includes a reverse case 15 a to which the steel plates 15 d are attached, a reverse tube 15 b to which the friction plates 15 e are attached, and a reverse clutch cylinder 15 c .
- the friction plates 15 e are capable of being brought into contact with the steel plates 15 d under pressure.
- the reverse clutch cylinder 15 c generates contact pressure using hydraulic oil pressure.
- the reverse case 15 a is fixed to the reverse clutch shaft 15 f .
- the reverse tube 15 b is loosely fitted to the reverse clutch shaft 15 f to be rotational.
- the rear end section of the reverse tube 15 b is inserted in the inner circumference of the reverse case 15 a .
- a reverse gear 44 is integrally formed with the outer circumference of the reverse case 15 a .
- a reverse reduction gear 45 is integrally formed with the front end section of the reverse tube 15 b .
- the reverse gear 44 is constantly engaged with the forward gear 42 of the forward clutch 14 .
- the forward reduction gear 43 and the reverse reduction gear 45 are constantly engaged with an output gear 46 .
- the output gear 46 is fixed to the rear end section of the output shaft 16 .
- the reverse clutch shaft 15 f configures the support shaft of the reverse clutch 15 .
- the forward/reverse switching mechanism 20 has a reduction function that, in the forward state, reduces the rotational power of the input shaft 13 in accordance with the reduction ratio of the input gear 13 a and the input relay gear 14 g and the reduction ratio of the forward reduction gear 43 and the output gear 46 and transmits the reduced rotational power to the output shaft 16 . Additionally, the forward/reverse switching mechanism 20 has a reduction function that, in the reverse state, reduces the rotational power of the input shaft 13 in accordance with the reduction ratio of the input gear 13 a and the input relay gear 14 g , the reduction ratio of the forward gear 42 and the reverse gear 44 , and the reduction ratio of the reverse reduction gear 45 and the output gear 46 and transmits the reduced rotational power to the output shaft 16 .
- the forward clutch 14 and the reverse clutch 15 are hydraulic friction clutches and, more specifically, are multiplate wet clutches.
- the forward clutch 14 and the reverse clutch 15 have different clutch sizes from each other.
- the clutch size of the reverse clutch 15 is smaller than the clutch size of the forward clutch 14 in this embodiment.
- the input gear 13 a and the input relay gear 14 g configure an input gear group.
- the forward reduction gear 43 , the reverse reduction gear 45 , and the output gear 46 configure an output gear group.
- the gears 13 a , 14 g , 42 , 43 , 44 , 45 , and 46 are all helical gears in which teeth are cut at an angle with respect to the axis.
- the gears may be other gears such as spur gears.
- the front end section of the output shaft 16 and the front end section of the propeller shaft 6 are rotationally supported in the reduction housing 18 c .
- a reduction drive gear 31 is fixed to the front end section of the output shaft 16 .
- a reduction output gear 35 is fixed to the front end section (upstream section) of the propeller shaft 6 .
- the reduction drive gear 31 of the output shaft 16 is constantly engaged with the reduction output gear 35 of the propeller shaft 6 .
- the reduction mechanism 17 has a reduction function that reduces the rotational power of the output shaft 16 in accordance with the reduction ratio of the reduction drive gear 31 and the reduction output gear 35 and transmits the reduced rotational power to the propeller shaft 6 .
- the reduction drive gear 31 and the reduction output gear 35 are conical gears in which teeth are axially and continuously profile-shifted into a conical shape.
- the reduction drive gear 31 and the reduction output gear 35 configure the reduction mechanism 17 having a fixed reduction ratio.
- the rotational power of the output shaft 16 is reduced to the fixed reduction ratio and transmitted to the propeller shaft 6 by the engagement between the reduction drive gear 31 and the reduction output gear 35 .
- Employing a plurality of conical gears as the gears constituting the reduction mechanism 17 allows the shaft angle of the propeller shaft 6 to be set to various angles as viewed from the side depending on the combination of the plurality of conical gears. For example, in the ski boat 1 , the shaft angle of the propeller shaft 6 can be easily increased.
- the forward clutch 14 When the forward/reverse lever is manipulated to the forward position, the forward clutch 14 is brought into a power connected state (the steel plates 14 d of the forward case 14 a and the friction plates 14 e of the forward tube 14 b are pressed together using the hydraulic oil pressure), and the reverse clutch 15 is in a power disconnected state.
- the forward clutch 14 allows the forward reduction gear 43 to integrally rotate with the forward clutch shaft 14 f .
- the rotational power of the engine 10 is transmitted from the input shaft 13 to the output shaft 16 via the forward clutch shaft 14 f and the forward clutch 14 and is transmitted from the output shaft 16 to the propeller shaft 6 via the reduction mechanism 17 .
- the watercraft 1 is brought into a forward state in which the rotational power of the engine 10 is transmitted to the propeller shaft 6 as the output in the forward direction.
- the forward traveling speed of the watercraft 1 during normal traveling is adjusted by the throttle lever in the cockpit 3 .
- the rotational power of the input shaft 13 is reduced in accordance with the reduction ratio of the input gear 13 a and the input relay gear 14 g and the reduction ratio of the forward reduction gear 43 and the output gear 46 and is transmitted to the output shaft 16 .
- the rotational power of the output shaft 16 is reduced in accordance with the reduction ratio of the reduction mechanism 17 (the reduction drive gear 31 and the reduction output gear 35 ) and is transmitted to the propeller shaft 6 .
- the reverse clutch 15 When the forward/reverse lever is manipulated to the reverse position, the reverse clutch 15 is brought into the power connected state (the steel plates 15 d of the reverse case 15 a and the friction plates 15 e of the reverse tube 15 b are pressed together using the hydraulic oil pressure), and the forward clutch 14 is in the power disconnected state.
- the reverse clutch 15 allows the reverse reduction gear 45 to integrally rotate with the reverse clutch shaft 15 f .
- the rotational power of the engine 10 is transmitted from the input shaft 13 to the output shaft 16 via the forward clutch shaft 14 f , the reverse clutch shaft 15 f , and the reverse clutch 15 .
- the output shaft 16 rotates in reverse to the input shaft 13 , and the reverse rotational power of the output shaft 16 is transmitted to the propeller shaft 6 via the reduction mechanism 17 .
- the watercraft 1 is brought into a reverse state in which the rotational power of the engine 10 is transmitted to the propeller shaft 6 as the output in the reverse direction.
- the reverse traveling speed of the watercraft 1 during normal traveling is also adjusted by the throttle lever.
- the rotational power of the input shaft 13 is reduced in accordance with the reduction ratio of the input gear 13 a and the input relay gear 14 g , the reduction ratio of the forward gear 42 and the reverse gear 44 , and the reduction ratio of the reverse reduction gear 45 and the output gear 46 and is transmitted to the output shaft 16 .
- the rotational power of the output shaft 16 is reduced in accordance with the reduction ratio of the reduction mechanism 17 and is transmitted to the propeller shaft 6 .
- the watercraft 1 When the forward/reverse lever is manipulated to the neutral position so that the forward clutch 14 and the reverse clutch 15 are brought into the power disconnected state, the watercraft 1 is brought into a neutral state in which the rotational power of the engine 10 is not transmitted to the output shaft 16 and thus not transmitted to the propeller shaft 6 . Although both the clutches 14 and 15 are in the power disconnected state, the rotational power of the input shaft 13 is transmitted to the forward clutch shaft 14 f via the input gear 13 a and the input relay gear 14 g . Thus, the hydraulic pump 19 , which is coupled to the front end section of the forward clutch shaft 14 f , is operated.
- the reverse gear 11 includes the input shaft 13 , the forward/reverse switching mechanism 20 , the output shaft 16 , and the reduction mechanism 17 .
- the input shaft 13 receives the rotational power of the main engine, which is the engine 10 in this embodiment.
- the forward/reverse switching mechanism 20 switches the rotational power of the input shaft 13 among the forward, neutral, and reverse states.
- the output shaft 16 outputs the rotational power of the forward/reverse switching mechanism 20 .
- the reduction mechanism 17 reduces the rotational power of the output shaft 16 and transmits the reduced rotational power to the propeller shaft 6 .
- the forward/reverse housing 18 b which accommodates the forward/reverse switching mechanism 20
- the reduction housing 18 c which accommodates the reduction mechanism 17
- the forward/reverse switching mechanism 20 has the reduction function so that the rotational speed of the input shaft 13 differs from the rotational speed of the output shaft 16 , and the reduction ratio of the reduction mechanism 17 is fixed.
- the reduction mechanism 17 may have a common structure, and the forward/reverse switching mechanism 20 may be changed to one that has a desired reduction ratio.
- the reduction housing 18 c may be shared among different models and specifications, and the reverse gear 11 may be easily applied to a plurality of models and specifications of the watercrafts such as the ski boat 1 only by developing variations of the forward/reverse housing 18 b .
- the rotational power of the output shaft 16 is transmitted to the propeller shaft 6 by the engagement between the reduction drive gear 31 , which is provided on the output shaft 16 , and the reduction output gear 35 , which is provided on the propeller shaft 6 , and the reduction mechanism 17 has the fixed reduction ratio.
- the number of the gears constituting the reduction mechanism 17 is reduced to reduce the size of the reduction mechanism 17 and the space occupied by the reduction mechanism 17 and to consequently reduce the size of the entire reverse gear 11 and the space occupied by the entire reverse gear 11 .
- This configuration improves the versatility of the reverse gear 11 and enables the reverse gear 11 to be mounted on the watercraft 1 that has a limited height.
- the size of the reduction mechanism 17 and the space occupied by the reduction mechanism 17 are reduced by reducing the number of the gears constituting the reduction mechanism 17 .
- the height of the reduction housing 18 c and the reduction lid member 18 d is reduced, and the length of the reduction housing 18 c is reduced in the axial direction.
- This configuration increases the space in the watercraft such as the occupant's space S so that, for example, a space for mounting the seat 7 (refer to FIG. 1 ) is provided above the reduction mechanism 17 and enables the reverse gear 11 to be mounted on the watercraft 1 that has a limited height.
- the forward/reverse switching mechanism 20 includes the input gear group (the input gear 13 a and the input relay gear 14 g ) and the output gear group (the forward reduction gear 43 , the reverse reduction gear 45 , and the output gear 46 ).
- the input gear group and the output gear group are configured by a plurality of gears engaged with one another.
- the reduction ratio of the forward/reverse switching mechanism 20 is changed by replacing at least one of the input gear group and the output gear group.
- the replacement of at least one of the input gear group and the output gear group consequently changes the reduction ratio of the entire reverse gear 11 .
- a plurality of reduction ratios can be selected by the combination of the forward/reverse switching mechanism 20 and the reduction mechanism 17 without changing the reduction ratio of the reduction mechanism 17 .
- This configuration improves the ease in variation development of the reverse gear 11 while achieving the commonality of the reduction mechanism 17 , the lid members 18 a and 18 d , and the housings 18 b and 18 c among models and specifications and contributes to improving the versatility and increasing the range of application of the reverse gear 11 .
- the clutch size of the reverse clutch 15 may be smaller than the clutch size of the forward clutch 14 .
- the size of the forward/reverse switching mechanism 20 is reduced, and the space occupied by the forward/reverse switching mechanism 20 is reduced. This consequently further reduces the size of the reverse gear 11 and the space occupied by the reverse gear 11 .
- FIGS. 6 to 8 illustrate a reverse gear 11 according to a second embodiment.
- the forward clutch 14 and the reverse clutch 15 are arranged next one another in the lateral direction.
- the second embodiment differs from the first embodiment in that the input shaft 13 and the output shaft 16 are coaxially arranged.
- the single-line diagram of the power transmission system of the second embodiment is the same as FIG. 5 .
- the reverse gear 11 of the second embodiment since the input shaft 13 and the output shaft 16 are coaxially arranged, and the forward clutch 14 and the reverse clutch 15 are arranged next to one another in the lateral direction, the height of the forward/reverse switching mechanism 20 and the reduction mechanism 17 is reduced, and the shape of the left and right sides of the forward/reverse housing 18 b is well-balanced.
- This configuration further reduces the size of the reverse gear 11 , improves the versatility of the reverse gear 11 , and enables the reverse gear 11 to be mounted on the watercraft 1 that has a limited height.
- the sizes of the clutches 14 and 15 are the same in the reverse gear 11 of the second embodiment.
- the forward/reverse switching mechanism 20 may include the forward clutch 14 and the reverse clutch 15 that have different clutch sizes from each other in the above-described second embodiment.
- the clutch size of the reverse clutch 15 may be smaller than the clutch size of the forward clutch 14 .
- the gears 13 a , 14 g , 42 , 43 , 44 , 45 , and 46 are spur gears in which teeth are cut to be parallel to the axis.
- the gears may be other gears such as helical gears.
- FIGS. 9 to 11 illustrate a reverse gear 11 according to a third embodiment.
- the output shaft 16 is separable in the axial direction into front and rear sections.
- the output shaft 16 is divided into an upstream section and a downstream section.
- the front end portion of the upstream output shaft 16 and the rear end portion of the downstream output shaft 16 are coupled to each other with a coupling 27 to be slidable in the axial direction and not to rotate relative to each other (spline-fitted).
- the output shaft 16 is separated into the section corresponding to the forward/reverse housing 18 b and the section corresponding to the reduction housing 18 c . That is, the forward/reverse housing 18 b and the reduction housing 18 c are easily separated without changing the structure in the forward/reverse housing 18 b and the structure in the reduction housing 18 c.
- the output shaft 16 may be separable in the axial direction and coupled with the coupling 27 to prevent relative rotation in the above-described second embodiment.
- FIGS. 12 and 13 illustrate a reverse gear 11 according to a fourth embodiment.
- the output shaft 16 is separable in the axial direction into front and rear sections.
- the front and rear sections of the output shaft 16 are coupled to each other with the coupling 27 to be slidable in the axial direction and not rotate relative to each other.
- the reduction mechanism 17 inside the reduction housing 18 c includes an idling shaft 32 .
- the idling shaft 32 is rotationally supported between the front end section of the output shaft 16 and the front end section of the propeller shaft 6 .
- the output shaft 16 , the idling shaft 32 , and the propeller shaft 6 are aligned with each other in plan view.
- a first idling gear 33 and a second idling gear 34 are fixed to the idling shaft 32 .
- the reduction drive gear 31 is fixed to the front end section of the output shaft 16 (the front end section of the downstream output shaft 16 ).
- the reduction output gear 35 is fixed to the front end section (upstream section) of the propeller shaft 6 .
- the reduction drive gear 31 of the output shaft 16 is constantly engaged with the first idling gear 33 of the idling shaft 32 .
- the second idling gear 34 of the idling shaft 32 is constantly engaged with the reduction output gear 35 of the propeller shaft 6 .
- the reduction drive gear 31 , the pair of idling gears 33 and 34 , and the reduction output gear 35 are conical gears.
- the gears 31 , 33 , 34 , and 35 configure the reduction mechanism 17 having a fixed reduction ratio.
- the rotational power of the output shaft 16 is reduced to the fixed reduction ratio by the reduction drive gear 31 , the pair of idling gears 33 and 34 , and the reduction output gear 35 .
- Employing the plurality of conical gears as gears constituting the reduction mechanism 17 facilitates setting the shaft angle of the propeller shaft 6 to various angles as viewed from the side depending on the combination of the plurality of conical gears. For example, the shaft angle of the propeller shaft 6 is easily increased in the ski boat 1 .
- the reduction mechanism 17 may include a plurality of conical gears having the same angle coupled to each other, or may include a plurality of conical gears having different angles coupled to each other.
- the forward/reverse housing 18 b which accommodates the forward/reverse switching mechanism 20
- the reduction housing 18 c which accommodates the reduction mechanism 17
- the forward/reverse switching mechanism 20 has a reduction function, the rotational speed of the input shaft 13 differs from the rotational speed of the output shaft 16 .
- the reduction mechanism 17 may have a common structure, and the forward/reverse switching mechanism 20 may be changed to one that has a desired reduction ratio.
- the idling shaft 32 may be rotationally supported between the front end section of the output shaft 16 and the front end section of the propeller shaft 6 to reduce the rotational power of the output shaft 16 to the fixed reduction ratio by the reduction drive gear 31 , the pair of idling gears 33 and 34 , and the reduction output gear 35 .
- FIGS. 15 and 16 illustrate a reverse gear 11 according to fifth and sixth embodiments based on the above-described third embodiment.
- the forward reduction gear 43 , the reverse reduction gear 45 , and the output gear 46 are conical gears, and the output shaft 16 is tilted.
- the forward reduction gear 43 , the reverse reduction gear 45 , and the output gear 46 are conical gears, and the reduction drive gear 31 and the reduction output gear 35 are spur gears.
- the output shaft 16 is tilted to extend parallel to the propeller shaft 6 .
- the output shaft 16 is not parallel to, for example, the input shaft 13 and is not positioned on the same plane as, for example, the input shaft 13 , there is no significant influence on reducing the height of the housings 18 b and 18 c as long as the inclination of the output shaft 16 is within the range that allows the output shaft 16 to be fitted in the reduction housing 18 c .
- the output shaft 16 may be a single shaft not separated in the axial direction into a front section and a rear section.
- the reverse gear 11 of the seventh embodiment differs from the reverse gear 11 of the above-described fourth embodiment in the configuration of the forward/reverse switching mechanism 20 .
- the reverse gear 11 of the seventh embodiment includes the forward clutch 14 and a reverse brake 61 as the forward/reverse switching mechanism 20 , which shifts the rotational power of the input shaft 13 among the forward, neutral, and reverse states.
- the forward/reverse switching mechanism 20 is accommodated in the forward/reverse housing 18 b .
- the forward/reverse switching mechanism 20 In the reverse state in which the output shaft 16 is rotated in reverse to the input shaft 13 , the forward/reverse switching mechanism 20 has a reduction function in which the rotational power of the input shaft 13 is reduced and transmitted to the output shaft 16 .
- the input shaft 13 and the output shaft 16 are coaxially arranged.
- the forward clutch 14 is located on the outer circumference of the output shaft 16
- the reverse brake 61 is located on the outer circumference of the forward clutch 14 .
- the forward clutch 14 is a hydraulic friction clutch and, more specifically, is a multiplate wet clutch.
- the reverse brake 61 is a hydraulic friction brake and, more specifically, is a multiplate wet brake.
- the forward clutch 14 is located at an upstream section of the output shaft 16 , which extends coaxially with the input shaft 13 , and includes the steel plates 14 d and the friction plates 14 e , which are alternately arranged.
- the forward clutch 14 includes the forward case 14 a to which the steel plates 14 d are attached, the forward tube 14 b , which is fixed to the forward case 14 a , and the forward clutch cylinder 14 c , which generates contact pressure (clutch pressure) using the hydraulic oil pressure.
- the forward case 14 a is fixed to the input shaft 13 .
- the rear end section of the output shaft 16 is inserted in the inner circumference of the forward case 14 a .
- the rear end section of the output shaft 16 is rotationally supported by the inner circumference of the forward case 14 a .
- the friction plates 14 e which are capable of being brought into contact with the steel plates 14 d under pressure, are provided on the outer circumferential portion of the rear end section of the output shaft 16 .
- the forward tube 14 b is rotationally fitted to the output shaft 16 .
- a reverse drive gear 21 is integrally formed on the outer circumferential portion of the front end section of the forward tube 14 b.
- the reverse brake 61 is located on the outer circumference of the forward clutch 14 to overlap the forward clutch 14 and includes, like the forward clutch 14 , steel plates 61 d and friction plates 61 e that are alternately arranged.
- the reverse brake 61 includes a reverse case 61 a to which steel plates 61 d are attached and a reverse brake cylinder 61 c .
- the reverse brake cylinder 61 c generates contact pressure by the hydraulic oil pressure.
- the reverse case 61 a is secured in the forward/reverse housing 18 b .
- the forward case 14 a is positioned on the inner circumference of the reverse case 61 a .
- the friction plates 61 e which are capable of being brought into contact with the steel plates 61 d under pressure, are provided on the outer circumferential portion of a rear-facing annular projection 23 a formed on a carrier 23 , which will be discussed below.
- the carrier 23 is loosely fitted to the forward tube 14 b to be rotational.
- a planetary reversing gear mechanism 22 is located on the output shaft 16 downstream of the forward clutch 14 and the reverse brake 61 (at a position close to the front of the rear section).
- the planetary reversing gear mechanism 22 includes the carrier 23 , which rotationally supports a plurality of sets of planetary gears 24 and reversing gears 25 .
- the carrier 23 is loosely fitted to the forward tube 14 b to be rotational.
- the group of planetary gears 24 are positioned on the front side of the carrier 23 at the same radial distance from the common axis.
- the group of reversing gears 25 are positioned on the front side of the carrier 23 at the same radial distance from the common axis.
- the radial distance between the axis and the planetary gears 24 is different from the radial distance between the axis and the planetary gears 25 .
- the planetary gears 24 of the carrier 23 are constantly engaged with the reverse drive gear 21 of the forward tube 14 b from radially outward.
- the planetary gears 24 are also constantly engaged with the corresponding reversing gears 25 .
- the reversing gears 25 are constantly engaged with a reverse driven gear 26 .
- the reverse driven gear 26 is fixed to the output shaft 16 at a position close to the front of the rear section.
- the output shaft 16 of the seventh embodiment is separable in the axial direction into a front section and a rear section.
- the front and rear sections are coupled to each other with the coupling 27 to be slidable in the axial direction and not to rotate relative to each other.
- the configuration of the reduction mechanism 17 which is accommodated in the reduction housing 18 c , is the same as the reduction mechanism 17 of the fourth embodiment described with reference to FIGS. 12 to 14 .
- the supply destination of the hydraulic oil is shifted to the forward clutch 14 (the forward clutch cylinder 14 c ), the reverse brake 61 (the reverse brake cylinder 61 c ), or neutral.
- the forward clutch 14 When the forward/reverse lever is manipulated to the forward position, and the forward clutch 14 is brought into the power connected state (the steel plates 14 d of the forward case 14 a and the friction plates 14 e of the output shaft 16 are pressed together using the hydraulic oil pressure), the reverse brake 61 is in the power disconnected state.
- the forward clutch 14 allows the input shaft 13 to rotate integrally with the output shaft 16 .
- the rotational power of the engine 10 is transmitted from the input shaft 13 to the output shaft 16 via the forward clutch 14 .
- the rotational power transmitted to the output shaft 16 is transmitted to the propeller shaft 6 via the reduction mechanism 17 .
- the watercraft 1 is brought into the forward state in which the rotational power of the engine 10 is transmitted to the propeller shaft 6 as the output in the forward direction.
- the forward traveling speed of the watercraft 1 during normal traveling is adjusted by the throttle lever in the cockpit 3 .
- the forward clutch 14 is in the power connected state, the rotation direction and the rotational speed of the reverse drive gear 21 and the reverse driven gear 26 are the same.
- the group of the planetary gears 24 and the group of the reversing gears 25 do not rotate, and the carrier 23 rotates in the same rotation direction and at the same rotational speed as the output shaft 16 .
- the forward clutch 14 When the forward/reverse lever is manipulated to the reverse position, and the reverse brake 61 is brought into the power connected state, the forward clutch 14 is in the power disconnected state, and the carrier 23 is secured to the reverse case 61 a .
- the rotational power of the engine 10 is transmitted from the input shaft 13 to the planetary gears 24 of the carrier 23 via the reverse drive gear 21 of the forward tube 14 b .
- the rotational power transmitted to the planetary gears 24 is transmitted to the reverse driven gear 26 of the output shaft 16 via the reversing gears 25 .
- the output shaft 16 is rotated in reverse to the input shaft 13 , and the reverse rotational power of the output shaft 16 is transmitted to the propeller shaft 6 via the reduction mechanism 17 .
- the watercraft 1 is brought into the reverse state in which the rotational power of the engine 10 is transmitted to the propeller shaft 6 as the output in the reverse direction.
- the reverse traveling speed of the watercraft 1 during normal traveling is also adjusted by the throttle lever.
- the rotational power of the input shaft 13 is reduced by the forward/reverse switching mechanism 20 in accordance with the reduction ratio of the planetary reversing gear mechanism 22 and is transmitted to the output shaft 16 .
- the watercraft 1 When the forward/reverse lever is manipulated to the neutral position so that the forward clutch 14 and the reverse brake 61 are both brought into the power disconnected state, the watercraft 1 is brought into the neutral state in which the rotational power of the engine 10 is not transmitted to the output shaft 16 and thus not transmitted to the propeller shaft 6 .
- the forward/reverse housing 18 b which accommodates the forward/reverse switching mechanism 20
- the reduction housing 18 c which accommodates the reduction mechanism 17
- the forward/reverse switching mechanism 20 has a reduction function so that the rotational speed of the input shaft 13 differs from the rotational speed of the output shaft 16 in the reverse state, and the reduction mechanism 17 has a fixed reduction ratio.
- the reduction mechanism 17 may have a common structure, and the forward/reverse switching mechanism 20 may be changed to one that has a desired reduction ratio. That is, the reduction housing 18 c may be shared among different models and specifications, and the reverse gear 11 may be easily applied to a plurality of models and specifications of the watercrafts such as the ski boat 1 only by developing variations of the forward/reverse housing 18 b . This eliminates the need for producing the reduction mechanism 17 that differs depending on models and specifications and thus reduces the production costs of models and specifications as a whole.
- the input shaft 13 and the output shaft 16 are coaxially arranged, the forward clutch 14 is located on the outer circumference of the output shaft 16 , the reverse brake 61 is located on the outer circumference of the forward clutch 14 , and the planetary reversing gear mechanism 22 is located on the output shaft 16 downstream of the forward clutch 14 and the reverse brake 61 .
- the reverse gear 11 the height of the housings 18 b and 18 c , which accommodate the input shaft 13 , the forward clutch 14 , the reverse brake 61 , and the output shaft 16 , is reduced, and the length of the housings 18 b and 18 c in the axial direction is reduced, resulting in reduction of the size of the reverse gear 11 .
- This configuration improves the versatility of the reverse gear 11 and enables the reverse gear 11 to be mounted on the watercraft 1 that has a limited height.
- the forward/reverse switching mechanism 20 includes the output gear groups (the reverse drive gear 21 , the planetary gears 24 , the reversing gears 25 , and the reverse driven gear 26 ) in which a plurality of gears are engaged with one another.
- the output gear groups the reverse drive gear 21 , the planetary gears 24 , the reversing gears 25 , and the reverse driven gear 26 .
- a plurality of reduction ratios can be selected by the combination of the forward/reverse switching mechanism 20 and the reduction mechanism 17 without changing the reduction ratio of the reduction mechanism 17 .
- the ease in variation development of the reverse gear 11 is improved. This contributes to improving the versatility and increasing the range of application of the reverse gear 11 .
- the gears of the forward/reverse switching mechanism 20 may be spur gears or helical gears.
- FIGS. 20 and 21 illustrate a reverse gear 11 according to an eighth embodiment based on the seventh embodiment.
- the conical angle of the reduction drive gear 31 and the reduction output gear 35 of the reduction mechanism 17 is greater than a certain value, the idling shaft 32 and the pair of idling gears 33 and 34 may be omitted, and the reduction drive gear 31 and the reduction output gear 35 may be directly engaged with each other like the above-described first to third embodiments.
- reducing the number of the gears constituting the reduction mechanism 17 reduces the height of the reduction housing 18 c and the reduction lid member 18 d and reduces the length of the reduction housing 18 c in the axial direction.
- the internal space such as the occupant's space S (refer to FIG. 1 ) is increased.
- This configuration provides the space for placing the seat 7 above the reduction mechanism 17 and enables the reverse gear 11 to be mounted on the watercraft 1 that has a limited height.
- a reverse gear 50 according to a reference example will be described with reference to FIGS. 22 to 25 .
- the input gear 13 a which is fixed to the front end section of the input shaft 13
- the input relay gear 14 g which is fixed to the rear end section of a reverse output shaft 51 .
- the reverse output shaft 51 extends parallel to the input shaft 13 .
- the input relay gear 14 g , the forward reduction gear 43 , and the reverse reduction gear 45 are provided on the reverse output shaft 51 in this order from the upstream end.
- the input relay gear 14 g is fixed to the reverse output shaft 51 .
- the forward reduction gear 43 is loosely fitted to the reverse output shaft 51 and is coupled by the forward clutch 14 , which is a multiplate wet clutch, to be capable of connecting and disconnecting power.
- the reverse reduction gear 45 is loosely fitted to the reverse output shaft 51 and is coupled by the reverse clutch 15 , which is a multiplate wet clutch, to be capable of connecting and disconnecting power.
- the forward reduction gear 43 is constantly engaged with a forward relay gear 53 fixed to the rear end section of a forward output shaft 52 .
- the forward output shaft 52 extends parallel to the input shaft 13 .
- the forward clutch 14 connects or disconnects the power transmission from the input shaft 13 to the forward output shaft 52
- the reverse clutch 15 connects or disconnects the power transmission from the input shaft 13 to the propeller shaft 6 .
- the hydraulic pump 19 (refer to FIG. 25 ), which supplies hydraulic oil to the forward clutch 14 and the reverse clutch 15 , is coupled to the front end section of the reverse output shaft 51 .
- a forward reduction drive gear 54 is fixed to the front end section of the forward output shaft 52 .
- the reverse reduction gear 45 which is loosely fitted to the reverse output shaft 51
- the forward reduction drive gear 54 which is fixed to the forward output shaft 52
- the input gear 13 a , the input relay gear 14 g , the forward reduction gear 43 , the reverse reduction gear 45 , and the forward relay gear 53 are helical gears
- the reduction output gear 35 and the forward reduction drive gear 54 are conical gears.
- the gears 13 a , 14 g , 43 , and 53 may be other gears such as spur gears.
- the forward/reverse switching mechanism 20 includes the input gear 13 a , the input relay gear 14 g , the forward clutch 14 , the reverse clutch 15 , the reverse output shaft 51 , the forward output shaft 52 , the forward reduction gear 43 , and the forward relay gear 53 .
- the reduction mechanism 17 includes the reduction output gear 35 , the reverse reduction gear 45 , and the forward reduction drive gear 54 .
- the reverse reduction gear 45 and the forward reduction drive gear 54 each configure a drive gear of the reduction output gear 35 .
- the forward/reverse lever in the cockpit 3 When the forward/reverse lever in the cockpit 3 is manipulated to the forward, reverse, or neutral position, the supply destination of the hydraulic oil is shifted to the forward clutch 14 , the reverse clutch 15 , or neutral.
- the forward clutch 14 When the forward/reverse lever is manipulated to the forward position, the forward clutch 14 is brought into the power connected state, and the reverse clutch 15 is in the power disconnected state.
- the forward clutch 14 causes the forward reduction gear 43 to rotate integrally with the reverse output shaft 51 .
- the rotational power of the engine 10 is transmitted from the input shaft 13 to the forward output shaft 52 via the reverse output shaft 51 and the forward clutch 14 , and the forward output shaft 52 is rotated in the same direction as the input shaft 13 .
- the rotational force is transmitted from the forward output shaft 52 to the propeller shaft 6 via the reduction mechanism 17 .
- the watercraft 1 is brought into the forward state in which the rotational power of the engine 10 is transmitted to the propeller shaft 6 as the output in the forward direction.
- the rotational power of the input shaft 13 is reduced in accordance with the reduction ratio of the input gear 13 a and the input relay gear 14 g , the reduction ratio of the forward reduction gear 43 and the forward relay gear 53 , and the reduction ratio of the forward reduction drive gear 54 and the reduction output gear 35 .
- the rotational power that has been reduced is transmitted to the propeller shaft 6 .
- the reverse clutch 15 When the forward/reverse lever is manipulated to the reverse position, the reverse clutch 15 is brought into the power connected state, and the forward clutch 14 is in the power disconnected state. Thus, the reverse clutch 15 causes the reverse reduction gear 45 to rotate integrally with the reverse output shaft 51 , which is rotated in reverse to the input shaft 13 . Thus, the rotational power of the engine 10 is transmitted from the input shaft 13 to the propeller shaft 6 via the reverse output shaft 51 and the reverse clutch 15 . As a result, the watercraft 1 is brought into the reverse state in which the rotational power of the engine 10 is transmitted to the propeller shaft 6 as the output in the reverse direction.
- the rotational power of the input shaft 13 is reduced in accordance with the reduction ratio of the input gear 13 a and the input relay gear 14 g and the reduction ratio of the reverse reduction gear 45 and the reduction output gear 35 and is transmitted to the propeller shaft 6 .
- the reverse gear 50 (five helical gears and two conical gears) uses a reduced number of gears. This simplifies the configuration of the reverse gear 50 and reduces the manufacturing costs.
- the reverse gear 50 is capable of supplying oil to the clutches 14 and 15 through an oil passage in the reverse output shaft 51 .
- the forward clutch 14 and the reverse clutch 15 are provided separately on the forward clutch shaft 14 f and the reverse clutch shaft 15 f .
- the oil is supplied to the clutches 14 and 15 through oil passages in the clutch shafts 14 f and 15 f .
- Such an internal oil passage is formed by gun drilling.
- the reverse gear 50 (in which the reverse output shaft 51 includes the internal oil passage) has a reduced number of shafts that include the internal oil passage. That is, the number of shafts that use the gun drill is reduced. This simplifies the configuration of the reverse gear 50 and reduces the manufacturing costs.
- Both the forward clutch 14 and the reverse clutch 15 of the reverse gear 50 are provided on the reverse output shaft 51 .
- the clutch cases of the clutches 14 and 15 are shrink-fitted to the reverse output shaft 51 .
- the forward case 14 a of the forward clutch 14 is shrink-fitted to the forward clutch shaft 14 f
- the reverse case 15 a of the reverse clutch 15 is shrink-fitted to the reverse clutch shaft 15 f .
- the reverse gear 50 in which the number of the shrink-fitted shaft is one
- the reverse gear 50 includes the input shaft 13 , the forward/reverse switching mechanism 20 , the reverse output shaft 51 , the forward output shaft 52 , and the reduction mechanism 17 .
- the input shaft 13 receives rotational power of the engine 10 , which is the main engine.
- the forward/reverse switching mechanism 20 switches the rotational power of the input shaft 13 among the forward, neutral, and reverse states.
- the reverse output shaft 51 and the forward output shaft 52 output the rotational power of the forward/reverse switching mechanism 20 .
- the reduction mechanism 17 reduces the rotational power of the output shafts 51 and 52 and transmits the reduced rotational power to the propeller shaft 6 .
- the rotational speed of the input shaft 13 differs from the rotational speed of the reverse output shaft 51
- the rotational speed of the input shaft 13 differs from the rotational speed of the forward output shaft 52 .
- the reduction mechanism 17 transmits the rotational power of the output shafts 51 and 52 to the propeller shaft 6 by the engagement of the reverse reduction gear 45 and the forward reduction drive gear 54 , which are provided on the output shafts 51 and 52 , with the reduction output gear 35 , which is provided on the propeller shaft 6 .
- the reverse gear 50 obtains a desired reduction ratio by the combination of the forward/reverse switching mechanism 20 and the reduction mechanism 17 , the number of the gears constituting the reduction mechanism 17 is reduced.
- This configuration improves the versatility of the reverse gear 50 and enables the reverse gear 50 to be mounted on the watercraft 1 that has a limited height.
- the height of the housing of the reduction mechanism 17 is reduced, and the length of the housing of the reduction mechanism 17 in the axial direction is reduced by reducing the number of the gears constituting the reduction mechanism 17 .
- the space in the watercraft such as the occupant's space S (refer to FIG. 1 ) is increased.
- This configuration provides a space for mounting the seat 7 above the reduction mechanism 17 and enables the reverse gear 50 to be mounted on the watercraft 1 that has a limited height.
- the forward/reverse switching mechanism 20 includes the input gear group (the input gear 13 a and the input relay gear 14 g ), which includes a plurality of gears engaged with each other.
- the reduction ratio of the forward/reverse switching mechanism 20 is changed by replacing the input gear group.
- a plurality of reduction ratios can be selected by the combination of the forward/reverse switching mechanism 20 and the reduction mechanism 17 without changing the reduction ratio of the reduction mechanism 17 .
- This configuration improves the ease in variation development of the reverse gear 50 while achieving the commonality of the reduction mechanism 17 among models and specifications and contributes to improving the versatility and increasing the range of application of the reverse gear 50 .
- the forward/reverse switching mechanism 20 may include the forward clutch 14 and the reverse clutch 15 that have different clutch sizes from each other.
- the clutch size of the reverse clutch 15 may be smaller than the clutch size of the forward clutch 14 .
- the size of the forward/reverse switching mechanism 20 and the space occupied by the forward/reverse switching mechanism 20 are reduced. This consequently reduces the size of the reverse gear 50 and the space occupied by the reverse gear 50 .
- the forward clutch 14 and the reverse clutch 15 may be swapped so that the rotational power of the input shaft 13 is transmitted to the propeller shaft 6 via the output shaft 51 as the forward output, and the rotational power of the input shaft 13 is transmitted to the propeller shaft 6 via the output shafts 51 and 52 as the reverse output.
- the reduction mechanism 17 is not limited to a V-drive system, but may be an angle drive system or a parallel shaft system.
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Abstract
A reverse gear for watercrafts includes an input shaft that receives rotational power of a main engine. A forward/reverse switching mechanism includes a reduction function and switches the rotational power of the input shaft among forward, neutral, and reverse states. An output shaft outputs the rotational power of the forward/reverse switching mechanism and rotates at a rotational speed that differs from a rotational speed of the input shaft due to the reduction function of the forward/reverse switching mechanism. A reduction mechanism includes a fixed reduction ratio, and reduces the rotational power of the output shaft and transmits the reduced rotational power to a propeller shaft. A forward/reverse housing accommodates the forward/reverse switching mechanism. A reduction housing accommodates the reduction mechanism. The forward/reverse housing and the reduction housing are detachably coupled one behind the other in an axial direction of the output shaft.
Description
- The present application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2016-187427, filed Sep. 26, 2016. The contents of this application are incorporated herein by reference in their entirety.
- The present invention relates to reverse gears for watercrafts that transmit rotational power of a main engine to a propeller. The present invention also relates to watercrafts equipped with such a reverse gear.
- Japanese Unexamined Patent Application Publication No. 7-17486 and Japanese Unexamined Utility Model Application Publication No. 6-78637 disclose reverse gears (marine gears) for watercrafts such as ski boats and pleasure boats. Such a reverse gear includes a forward clutch and a reverse clutch, which shift rotational power of an engine among forward rotation, neutral, and reverse rotation, and a reduction mechanism, which reduces the rotational power transmitted via the forward clutch or the reverse clutch and transmits the reduced rotational power to a propeller shaft.
- The contents of Japanese Unexamined Patent Application Publication No. 7-17486 and Japanese Unexamined Utility Model Application Publication No. 6-78637 are incorporated herein by reference in their entirety.
- It has been desired to achieve commonality of platforms (basic design) among models of the reverse gear as much as possible to reduce costs and effectively use resources by simplifying the process for producing the reverse gears. However, since the size of the reverse gear generally differs depending on models and specifications in accordance with the engine and the work capacity, the commonality of components and the ease in developing variations have not been considered. Unfortunately, such a situation does not respond to the increasing demand for cost reduction and effective use of resources.
- Accordingly, it is a technical object of the present invention to provide a reverse gear that has been improved upon consideration of the above-mentioned current state and to provide a watercraft equipped with the reverse gear.
- According to one aspect of the present invention for watercrafts, a reverse gear includes an input shaft, a forward/reverse switching mechanism, an output shaft, a reduction mechanism, a forward/reverse housing, and a reduction housing. The input shaft is configured to receive rotational power of a main engine. The forward/reverse switching mechanism includes a reduction function and is configured to switch the rotational power of the input shaft among forward, neutral, and reverse states. The output shaft is configured to output the rotational power of the forward/reverse switching mechanism and to rotate at a rotational speed that differs from a rotational speed of the input shaft due to the reduction function of the forward/reverse switching mechanism. The reduction mechanism includes a fixed reduction ratio and is configured to reduce the rotational power of the output shaft and to transmit the reduced rotational power to a propeller shaft. The forward/reverse housing accommodates the forward/reverse switching mechanism. The reduction housing accommodates the reduction mechanism. The forward/reverse housing and the reduction housing are detachably coupled one behind the other in an axial direction of the output shaft.
- In the first aspect of the present invention, the forward/reverse switching mechanism may include at least one of an input gear group and an output gear group. The input gear group and the output gear group may each include a plurality of gears engaged with one another. The forward/reverse switching mechanism may include a reduction ratio that is changed by replacing at least one of the input gear group and the output gear group.
- In the first aspect of the present invention, the forward/reverse switching mechanism may include a forward clutch and a reverse clutch that differ in a clutch size from each other.
- According to the embodiment of the present invention, a reverse gear includes an input shaft, a forward/reverse switching mechanism, an output shaft, a reduction mechanism, a forward/reverse housing, and a reduction housing. The input shaft is configured to receive rotational power of a main engine. The forward/reverse switching mechanism includes a reduction function and is configured to switch the rotational power of the input shaft among forward, neutral, and reverse states. The output shaft is configured to output the rotational power of the forward/reverse switching mechanism and to rotate at a rotational speed that differs from a rotational speed of the input shaft due to the reduction function of the forward/reverse switching mechanism. The reduction mechanism includes a fixed reduction ratio and is configured to reduce the rotational power of the output shaft and to transmit the reduced rotational power to a propeller shaft. The forward/reverse housing accommodates the forward/reverse switching mechanism. The reduction housing accommodates the reduction mechanism. The forward/reverse housing and the reduction housing are detachably coupled one behind the other in an axial direction of the output shaft. Thus, in achieving commonality of platforms of the reverse gears among, for example, models, the reduction mechanism may have a common structure, and the forward/reverse switching mechanism may be changed with one that has a desired reduction ratio. That is, the reduction housing may be shared among different models and specifications, and the reverse gear may be easily applied to a plurality of models and specifications of the watercrafts only by developing variations of the forward/reverse housing. This eliminates the need for producing the reduction mechanism that differs depending on models and specifications and thus reduces the production costs of models and specifications as a whole. Additionally, since the reduction ratio of the reduction mechanism is fixed, the number of gears constituting the reduction mechanism is reduced to reduce the size of the reduction mechanism and the space occupied by the reduction mechanism. This consequently reduces the size of the entire reverse gear and the space occupied by the entire reverse gear. This configuration improves the versatility of the reverse gear and enables the reverse gear to be mounted on the watercraft that has a limited height.
- With the reverse gear according to the embodiment of the present invention, the forward/reverse switching mechanism may include at least one of an input gear group and an output gear group. The input gear group and the output gear group may each include a plurality of gears engaged with one another. The reduction ratio of the forward/reverse switching mechanism may be changed by replacing at least one of the input gear group and the output gear group. In this case, although the reduction ratio of the reduction mechanism is fixed, a plurality of reduction ratios can be selected by the combination of the forward/reverse switching mechanism and the reduction mechanism in the entire reverse gear. Thus, while achieving the commonality of the reduction mechanism among models and specifications, the ease in variation development of the reverse gear is improved. This contributes to improving the versatility and increasing the range of application of the reverse gear.
- With the reverse gear according to the embodiment of the present invention, the forward/reverse switching mechanism may include a forward clutch and a reverse clutch that differ in a clutch size from each other. In this case, by reducing the clutch size of the reverse clutch compared with the clutch size of the forward clutch, the size of the forward/reverse switching mechanism and the space occupied by the forward/reverse switching mechanism are reduced. This consequently further reduces the size of the reverse gear and the space occupied by the reverse gear.
- With the watercraft according to the embodiment of the present invention, the reverse gear according to the embodiment of the present invention that reduces the production costs of models and specifications as a whole is mounted on a hull. This reduces the costs of the reverse gear and consequently reduces the production costs of the entire watercraft.
- A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
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FIG. 1 is a schematic side view of a ski boat; -
FIG. 2 is a side view of a reverse gear according to a first embodiment; -
FIG. 3 is a plan view of the reverse gear according to the first embodiment; -
FIG. 4 is a schematic front view of the reverse gear according to the first embodiment illustrating how the gears are engaged; -
FIG. 5 is a single-line diagram of a power transmission system of the reverse gear according to the first embodiment; -
FIG. 6 is a side view of a reverse gear according to a second embodiment; -
FIG. 7 is a plan view of the reverse gear according to the second embodiment; -
FIG. 8 is a schematic front view of the reverse gear according to the second embodiment illustrating how the gears are engaged; -
FIG. 9 is a side view of a reverse gear according to a third embodiment; -
FIG. 10 is a plan view of the reverse gear according to the third embodiment; -
FIG. 11 is a single-line diagram of a power transmission system of the reverse gear according to the third embodiment; -
FIG. 12 is a side view of a reverse gear according to a fourth embodiment; -
FIG. 13 is a plan view of the reverse gear according to the fourth embodiment; -
FIG. 14 is a single-line diagram of a power transmission system of the reverse gear according to the fourth embodiment; -
FIG. 15 is a single-line diagram of a power transmission system of a reverse gear according to a fifth embodiment; -
FIG. 16 is a single-line diagram of a power transmission system of a reverse gear according to a sixth embodiment; -
FIG. 17 is a side view of a reverse gear according to a seventh embodiment; -
FIG. 18 is a plan view of the reverse gear according to the seventh embodiment; -
FIG. 19 is a single-line diagram of a power transmission system of the reverse gear according to the seventh embodiment; -
FIG. 20 is a side view of a reverse gear according to an eighth embodiment; -
FIG. 21 is a single-line diagram of a power transmission system of the reverse gear according to the eighth embodiment; -
FIG. 22 is a side view of a reverse gear according to a reference example; -
FIG. 23 is a plan view of the reverse gear according to the reference example; -
FIG. 24 is a schematic front view of the reverse gear of the reference example illustrating how the gears are engaged; and -
FIG. 25 is a single-line diagram of a power transmission system of the reverse gear according to the reference example. - Hereinafter, an embodiment of the present invention will be described with reference to the drawings (
FIGS. 1 to 8 ). In the following description, when terms indicating a specific direction or a position (for example, “left and right” and “up and down”) are used as required, the bow of a watercraft will be referred to as the front, the stern of the watercraft will be referred to as the rear, and the front and rear are used as a reference. The watercraft is aski boat 1 in this embodiment. The terms are used for convenience of the description and do not intend to limit the technical range of the present invention. - First, the overview of the watercraft, which is the
ski boat 1 in this embodiment, will be described with reference toFIG. 1 . As illustrated inFIG. 1 , theski boat 1 includes a hull 2, acockpit 3, a rudder 4, and apropeller 5. Thecockpit 3 is located on the upper surface of the hull at the center. The rudder 4 is provided on the bottom of the hull 2 at the watercraft's stern. Thepropeller 5 is located in front of the rudder 4 on the bottom of the hull 2 at the watercraft's stern. Apropeller shaft 6 is supported on the bottom of the hull 2 at the watercraft's stern. Thepropeller shaft 6 rotates thepropeller 5. Thepropeller 5 is secured to the projecting end of thepropeller shaft 6. - Although detailed illustration is omitted, a steering wheel, a forward/reverse manipulator, a dead-slow travel manipulator, and a speed manipulator are provided in the
cockpit 3. The steering wheel changes the traveling direction of the hull 2 to left and right by steering. The forward/reverse manipulator shifts the traveling direction of the hull 2 between forward and reverse. The forward/reverse manipulator is a forward/reverse lever. The dead-slow travel manipulator causes the hull 2 to travel at dead slow. The dead-slow travel manipulator is a trawling lever. The speed manipulator sets and maintains the output rotational speed of an internal-combustion engine 10, which will be discussed below. The speed manipulator is a throttle lever. The manipulators are not limited to the levers, but may be in other forms such as dials. An occupant's space S is provided at the rear section of thecockpit 3. For example, aseat 7 is located in the occupant's space S. - A main engine, that is, a drive source of the
propeller 5 is theengine 10. Theengine 10 and areverse gear 11 are provided on the inner bottom portion of the hull 2 at the watercraft's stern. Thereverse gear 11 transmits the rotational power of theengine 10 to thepropeller 5. The rotational power transmitted to thepropeller shaft 6 from theengine 10 via thereverse gear 11 drivingly rotates thepropeller 5. Thereverse gear 11 of the embodiment is a V-drive system in which, as viewed from the side, the shaft angle of thepropeller shaft 6 is set to an acute angle (the angle between an input shaft 13 (or an output shaft 16) and thepropeller shaft 6 is set to an acute angle as viewed from the side). Thereverse gear 11 is located in front of theengine 10. -
FIGS. 2 to 5 illustrate thereverse gear 11 according to a first embodiment. As illustrated inFIGS. 2 to 5 , thereverse gear 11 of the first embodiment includes theinput shaft 13, a forward/reverse switching mechanism 20, theoutput shaft 16, and areduction mechanism 17. Theinput shaft 13 is coupled to aflywheel 12 of theengine 10. The forward/reverse switching mechanism 20 switches the rotational power of theinput shaft 13 among forward, neutral, and reverse states. Theoutput shaft 16 outputs the rotational power of the forward/reverse switching mechanism 20. Thereduction mechanism 17 reduces the rotational power of theoutput shaft 16 and transmits the reduced rotational power to thepropeller shaft 6. - An outer case of the
reverse gear 11 includes aclutch lid member 18 a, a hollow box-like forward/reverse housing 18 b, ahollow reduction housing 18 c, and areduction lid member 18 d. Theclutch lid member 18 a is located at the rear section. Thehollow reduction housing 18 c is L-shaped as viewed from the side. Thereduction lid member 18 d is located at the front section. Theclutch lid member 18 a is detachably coupled to the rear surface of the forward/reverse housing 18 b with a plurality of bolts. The front surface of the forward/reverse housing 18 b is detachably coupled to the rear surface of the body portion of thereduction housing 18 c with a plurality of bolts. The front surface of thereduction housing 18 c is detachably coupled to thereduction lid member 18 d with a plurality of bolts. The forward/reverse housing 18 b accommodates, for example, theinput shaft 13, the upstream section of theoutput shaft 16, and the forward/reverse switching mechanism 20. Thereduction housing 18 c accommodates the downstream section of theoutput shaft 16, thereduction mechanism 17, and the upstream section of thepropeller shaft 6. Theinput shaft 13 projects rearward from the rear surface of theclutch lid member 18 a. Thepropeller shaft 6 projects diagonally downward and rearward from the rear surface of a downwardly extending portion of thereduction housing 18 c and projects from the watercraft's bottom. The lower the height of the upper surfaces of thelid members housings FIG. 1 ). - An
input gear 13 a is fixed to the front end section of theinput shaft 13. Theinput gear 13 a is constantly engaged with aninput relay gear 14 g. Theinput relay gear 14 g is fixed to the rear end section of a forwardclutch shaft 14 f. The forwardclutch shaft 14 f extends parallel to theinput shaft 13. Aforward clutch 14 is located on the forwardclutch shaft 14 f and includessteel plates 14 d andfriction plates 14 e that are alternately arranged. Theforward clutch 14 includes aforward case 14 a to which thesteel plates 14 d are attached, aforward tube 14 b to which thefriction plates 14 e are attached, and a forwardclutch cylinder 14 c. Thefriction plates 14 e are capable of being brought into contact with thesteel plates 14 d under pressure. The forwardclutch cylinder 14 c generates contact pressure using hydraulic oil pressure. Theforward case 14 a is fixed to the forwardclutch shaft 14 f. Theforward tube 14 b is loosely fitted to the forwardclutch shaft 14 f to be rotational. The rear end section of theforward tube 14 b is inserted in the inner circumference of theforward case 14 a. Aforward gear 42 is integrally formed with the outer circumference of theforward case 14 a. Aforward reduction gear 43 is integrally formed at the front end section of theforward tube 14 b. The forwardclutch shaft 14 f configures a support shaft of theforward clutch 14. Ahydraulic pump 19 is coupled to the front end section of the forwardclutch shaft 14 f. Thehydraulic pump 19 supplies hydraulic oil to theforward clutch 14 and areverse clutch 15. - The reverse clutch 15 is located on a reverse
clutch shaft 15 f. The reverseclutch shaft 15 f extends parallel to theinput shaft 13. Like theforward clutch 14, the reverse clutch 15 includessteel plates 15 d andfriction plates 15 e that are alternately arranged. The reverse clutch 15 includes areverse case 15 a to which thesteel plates 15 d are attached, areverse tube 15 b to which thefriction plates 15 e are attached, and a reverseclutch cylinder 15 c. Thefriction plates 15 e are capable of being brought into contact with thesteel plates 15 d under pressure. The reverseclutch cylinder 15 c generates contact pressure using hydraulic oil pressure. Thereverse case 15 a is fixed to the reverseclutch shaft 15 f. Thereverse tube 15 b is loosely fitted to the reverseclutch shaft 15 f to be rotational. The rear end section of thereverse tube 15 b is inserted in the inner circumference of thereverse case 15 a. Areverse gear 44 is integrally formed with the outer circumference of thereverse case 15 a. Areverse reduction gear 45 is integrally formed with the front end section of thereverse tube 15 b. Thereverse gear 44 is constantly engaged with theforward gear 42 of theforward clutch 14. Theforward reduction gear 43 and thereverse reduction gear 45 are constantly engaged with anoutput gear 46. Theoutput gear 46 is fixed to the rear end section of theoutput shaft 16. The reverseclutch shaft 15 f configures the support shaft of thereverse clutch 15. - The forward/
reverse switching mechanism 20 has a reduction function that, in the forward state, reduces the rotational power of theinput shaft 13 in accordance with the reduction ratio of theinput gear 13 a and theinput relay gear 14 g and the reduction ratio of theforward reduction gear 43 and theoutput gear 46 and transmits the reduced rotational power to theoutput shaft 16. Additionally, the forward/reverse switching mechanism 20 has a reduction function that, in the reverse state, reduces the rotational power of theinput shaft 13 in accordance with the reduction ratio of theinput gear 13 a and theinput relay gear 14 g, the reduction ratio of theforward gear 42 and thereverse gear 44, and the reduction ratio of thereverse reduction gear 45 and theoutput gear 46 and transmits the reduced rotational power to theoutput shaft 16. - The
forward clutch 14 and the reverse clutch 15 are hydraulic friction clutches and, more specifically, are multiplate wet clutches. Theforward clutch 14 and the reverse clutch 15 have different clutch sizes from each other. Generally, since the reverse traveling does not require a great propulsive force compared with the forward traveling, the clutch size of the reverse clutch 15 is smaller than the clutch size of the forward clutch 14 in this embodiment. - The
input gear 13 a and theinput relay gear 14 g configure an input gear group. Theforward reduction gear 43, thereverse reduction gear 45, and theoutput gear 46 configure an output gear group. In this embodiment, thegears - The front end section of the
output shaft 16 and the front end section of thepropeller shaft 6 are rotationally supported in thereduction housing 18 c. Areduction drive gear 31 is fixed to the front end section of theoutput shaft 16. Areduction output gear 35 is fixed to the front end section (upstream section) of thepropeller shaft 6. Thereduction drive gear 31 of theoutput shaft 16 is constantly engaged with thereduction output gear 35 of thepropeller shaft 6. Thereduction mechanism 17 has a reduction function that reduces the rotational power of theoutput shaft 16 in accordance with the reduction ratio of thereduction drive gear 31 and thereduction output gear 35 and transmits the reduced rotational power to thepropeller shaft 6. - The
reduction drive gear 31 and thereduction output gear 35 are conical gears in which teeth are axially and continuously profile-shifted into a conical shape. Thereduction drive gear 31 and thereduction output gear 35 configure thereduction mechanism 17 having a fixed reduction ratio. The rotational power of theoutput shaft 16 is reduced to the fixed reduction ratio and transmitted to thepropeller shaft 6 by the engagement between thereduction drive gear 31 and thereduction output gear 35. Employing a plurality of conical gears as the gears constituting thereduction mechanism 17 allows the shaft angle of thepropeller shaft 6 to be set to various angles as viewed from the side depending on the combination of the plurality of conical gears. For example, in theski boat 1, the shaft angle of thepropeller shaft 6 can be easily increased. - Next, operation of the
reverse gear 11 will be described. When the forward/reverse lever in the cockpit 3 (refer toFIG. 1 ) is manipulated to a forward, reverse, or neutral position, the supply destination of the hydraulic oil is shifted to the forward clutch 14 (the forwardclutch cylinder 14 c), the reverse clutch 15 (the reverseclutch cylinder 15 c), or neutral. - When the forward/reverse lever is manipulated to the forward position, the
forward clutch 14 is brought into a power connected state (thesteel plates 14 d of theforward case 14 a and thefriction plates 14 e of theforward tube 14 b are pressed together using the hydraulic oil pressure), and the reverse clutch 15 is in a power disconnected state. Thus, theforward clutch 14 allows theforward reduction gear 43 to integrally rotate with the forwardclutch shaft 14 f. In this case, the rotational power of theengine 10 is transmitted from theinput shaft 13 to theoutput shaft 16 via the forwardclutch shaft 14 f and theforward clutch 14 and is transmitted from theoutput shaft 16 to thepropeller shaft 6 via thereduction mechanism 17. As a result, thewatercraft 1 is brought into a forward state in which the rotational power of theengine 10 is transmitted to thepropeller shaft 6 as the output in the forward direction. The forward traveling speed of thewatercraft 1 during normal traveling is adjusted by the throttle lever in thecockpit 3. - In the forward state, the rotational power of the
input shaft 13 is reduced in accordance with the reduction ratio of theinput gear 13 a and theinput relay gear 14 g and the reduction ratio of theforward reduction gear 43 and theoutput gear 46 and is transmitted to theoutput shaft 16. The rotational power of theoutput shaft 16 is reduced in accordance with the reduction ratio of the reduction mechanism 17 (thereduction drive gear 31 and the reduction output gear 35) and is transmitted to thepropeller shaft 6. - When the forward/reverse lever is manipulated to the reverse position, the reverse clutch 15 is brought into the power connected state (the
steel plates 15 d of thereverse case 15 a and thefriction plates 15 e of thereverse tube 15 b are pressed together using the hydraulic oil pressure), and theforward clutch 14 is in the power disconnected state. Thus, the reverse clutch 15 allows thereverse reduction gear 45 to integrally rotate with the reverseclutch shaft 15 f. In this case, the rotational power of theengine 10 is transmitted from theinput shaft 13 to theoutput shaft 16 via the forwardclutch shaft 14 f, the reverseclutch shaft 15 f, and thereverse clutch 15. Theoutput shaft 16 rotates in reverse to theinput shaft 13, and the reverse rotational power of theoutput shaft 16 is transmitted to thepropeller shaft 6 via thereduction mechanism 17. As a result, thewatercraft 1 is brought into a reverse state in which the rotational power of theengine 10 is transmitted to thepropeller shaft 6 as the output in the reverse direction. The reverse traveling speed of thewatercraft 1 during normal traveling is also adjusted by the throttle lever. - In the reverse state, the rotational power of the
input shaft 13 is reduced in accordance with the reduction ratio of theinput gear 13 a and theinput relay gear 14 g, the reduction ratio of theforward gear 42 and thereverse gear 44, and the reduction ratio of thereverse reduction gear 45 and theoutput gear 46 and is transmitted to theoutput shaft 16. The rotational power of theoutput shaft 16 is reduced in accordance with the reduction ratio of thereduction mechanism 17 and is transmitted to thepropeller shaft 6. - When the forward/reverse lever is manipulated to the neutral position so that the
forward clutch 14 and the reverse clutch 15 are brought into the power disconnected state, thewatercraft 1 is brought into a neutral state in which the rotational power of theengine 10 is not transmitted to theoutput shaft 16 and thus not transmitted to thepropeller shaft 6. Although both theclutches input shaft 13 is transmitted to the forwardclutch shaft 14 f via theinput gear 13 a and theinput relay gear 14 g. Thus, thehydraulic pump 19, which is coupled to the front end section of the forwardclutch shaft 14 f, is operated. - As clearly shown in the above description and
FIGS. 2 to 5 , thereverse gear 11 includes theinput shaft 13, the forward/reverse switching mechanism 20, theoutput shaft 16, and thereduction mechanism 17. Theinput shaft 13 receives the rotational power of the main engine, which is theengine 10 in this embodiment. The forward/reverse switching mechanism 20 switches the rotational power of theinput shaft 13 among the forward, neutral, and reverse states. Theoutput shaft 16 outputs the rotational power of the forward/reverse switching mechanism 20. Thereduction mechanism 17 reduces the rotational power of theoutput shaft 16 and transmits the reduced rotational power to thepropeller shaft 6. In thereverse gear 11, the forward/reverse housing 18 b, which accommodates the forward/reverse switching mechanism 20, and thereduction housing 18 c, which accommodates thereduction mechanism 17, are detachably coupled one behind the other in the axial direction of theoutput shaft 16. The forward/reverse switching mechanism 20 has the reduction function so that the rotational speed of theinput shaft 13 differs from the rotational speed of theoutput shaft 16, and the reduction ratio of thereduction mechanism 17 is fixed. Thus, in achieving commonality of the platform of thereverse gear 11 among, for example, models, thereduction mechanism 17 may have a common structure, and the forward/reverse switching mechanism 20 may be changed to one that has a desired reduction ratio. That is, thereduction housing 18 c may be shared among different models and specifications, and thereverse gear 11 may be easily applied to a plurality of models and specifications of the watercrafts such as theski boat 1 only by developing variations of the forward/reverse housing 18 b. This eliminates the need for producing thereduction mechanism 17 that differs depending on models and specifications and thus reduces the production costs of models and specifications as a whole. - In the
reverse gear 11, the rotational power of theoutput shaft 16 is transmitted to thepropeller shaft 6 by the engagement between thereduction drive gear 31, which is provided on theoutput shaft 16, and thereduction output gear 35, which is provided on thepropeller shaft 6, and thereduction mechanism 17 has the fixed reduction ratio. Thus, although a desired reduction ratio of theentire reverse gear 11 is obtained depending on the combination of the forward/reverse switching mechanism 20, which has the reduction function, and thereduction mechanism 17, the number of the gears constituting thereduction mechanism 17 is reduced to reduce the size of thereduction mechanism 17 and the space occupied by thereduction mechanism 17 and to consequently reduce the size of theentire reverse gear 11 and the space occupied by theentire reverse gear 11. This configuration improves the versatility of thereverse gear 11 and enables thereverse gear 11 to be mounted on thewatercraft 1 that has a limited height. - The size of the
reduction mechanism 17 and the space occupied by thereduction mechanism 17 are reduced by reducing the number of the gears constituting thereduction mechanism 17. For example, the height of thereduction housing 18 c and thereduction lid member 18 d is reduced, and the length of thereduction housing 18 c is reduced in the axial direction. This configuration increases the space in the watercraft such as the occupant's space S so that, for example, a space for mounting the seat 7 (refer toFIG. 1 ) is provided above thereduction mechanism 17 and enables thereverse gear 11 to be mounted on thewatercraft 1 that has a limited height. - In the
reverse gear 11, the forward/reverse switching mechanism 20 includes the input gear group (theinput gear 13 a and theinput relay gear 14 g) and the output gear group (theforward reduction gear 43, thereverse reduction gear 45, and the output gear 46). The input gear group and the output gear group are configured by a plurality of gears engaged with one another. The reduction ratio of the forward/reverse switching mechanism 20 is changed by replacing at least one of the input gear group and the output gear group. The replacement of at least one of the input gear group and the output gear group consequently changes the reduction ratio of theentire reverse gear 11. Thus, a plurality of reduction ratios can be selected by the combination of the forward/reverse switching mechanism 20 and thereduction mechanism 17 without changing the reduction ratio of thereduction mechanism 17. This configuration improves the ease in variation development of thereverse gear 11 while achieving the commonality of thereduction mechanism 17, thelid members housings reverse gear 11. - In the
reverse gear 11, as long as the forward/reverse switching mechanism 20 includes theforward clutch 14 and the reverse clutch 15 that have different clutch sizes from each other, the clutch size of the reverse clutch 15 may be smaller than the clutch size of theforward clutch 14. Thus, the size of the forward/reverse switching mechanism 20 is reduced, and the space occupied by the forward/reverse switching mechanism 20 is reduced. This consequently further reduces the size of thereverse gear 11 and the space occupied by thereverse gear 11. -
FIGS. 6 to 8 illustrate areverse gear 11 according to a second embodiment. In the second embodiment, theforward clutch 14 and the reverse clutch 15 are arranged next one another in the lateral direction. The second embodiment differs from the first embodiment in that theinput shaft 13 and theoutput shaft 16 are coaxially arranged. The single-line diagram of the power transmission system of the second embodiment is the same asFIG. 5 . - In the
reverse gear 11 of the second embodiment, since theinput shaft 13 and theoutput shaft 16 are coaxially arranged, and theforward clutch 14 and the reverse clutch 15 are arranged next to one another in the lateral direction, the height of the forward/reverse switching mechanism 20 and thereduction mechanism 17 is reduced, and the shape of the left and right sides of the forward/reverse housing 18 b is well-balanced. This configuration further reduces the size of thereverse gear 11, improves the versatility of thereverse gear 11, and enables thereverse gear 11 to be mounted on thewatercraft 1 that has a limited height. - The sizes of the
clutches reverse gear 11 of the second embodiment. However, the forward/reverse switching mechanism 20 may include theforward clutch 14 and the reverse clutch 15 that have different clutch sizes from each other in the above-described second embodiment. For example, the clutch size of the reverse clutch 15 may be smaller than the clutch size of theforward clutch 14. In thereverse gear 11 of the second embodiment, thegears -
FIGS. 9 to 11 illustrate areverse gear 11 according to a third embodiment. In the third embodiment, compared with the above-described first embodiment, theoutput shaft 16 is separable in the axial direction into front and rear sections. In this case, theoutput shaft 16 is divided into an upstream section and a downstream section. The front end portion of theupstream output shaft 16 and the rear end portion of thedownstream output shaft 16 are coupled to each other with acoupling 27 to be slidable in the axial direction and not to rotate relative to each other (spline-fitted). Thus, when the plurality of bolts that couple the forward/reverse housing 18 b to thereduction housing 18 c are removed to separate the forward/reverse housing 18 b from thereduction housing 18 c, theoutput shaft 16 is separated into the section corresponding to the forward/reverse housing 18 b and the section corresponding to thereduction housing 18 c. That is, the forward/reverse housing 18 b and thereduction housing 18 c are easily separated without changing the structure in the forward/reverse housing 18 b and the structure in thereduction housing 18 c. - Like the above-described third embodiment, the
output shaft 16 may be separable in the axial direction and coupled with thecoupling 27 to prevent relative rotation in the above-described second embodiment. -
FIGS. 12 and 13 illustrate areverse gear 11 according to a fourth embodiment. In the fourth embodiment, compared with the above-described second embodiment, theoutput shaft 16 is separable in the axial direction into front and rear sections. The front and rear sections of theoutput shaft 16 are coupled to each other with thecoupling 27 to be slidable in the axial direction and not rotate relative to each other. Thereduction mechanism 17 inside thereduction housing 18 c includes an idlingshaft 32. The idlingshaft 32 is rotationally supported between the front end section of theoutput shaft 16 and the front end section of thepropeller shaft 6. Theoutput shaft 16, the idlingshaft 32, and thepropeller shaft 6 are aligned with each other in plan view. Afirst idling gear 33 and asecond idling gear 34 are fixed to the idlingshaft 32. Thereduction drive gear 31 is fixed to the front end section of the output shaft 16 (the front end section of the downstream output shaft 16). Thereduction output gear 35 is fixed to the front end section (upstream section) of thepropeller shaft 6. Thereduction drive gear 31 of theoutput shaft 16 is constantly engaged with thefirst idling gear 33 of the idlingshaft 32. Thesecond idling gear 34 of the idlingshaft 32 is constantly engaged with thereduction output gear 35 of thepropeller shaft 6. - The
reduction drive gear 31, the pair of idling gears 33 and 34, and thereduction output gear 35 are conical gears. Thegears reduction mechanism 17 having a fixed reduction ratio. The rotational power of theoutput shaft 16 is reduced to the fixed reduction ratio by thereduction drive gear 31, the pair of idling gears 33 and 34, and thereduction output gear 35. Employing the plurality of conical gears as gears constituting thereduction mechanism 17 facilitates setting the shaft angle of thepropeller shaft 6 to various angles as viewed from the side depending on the combination of the plurality of conical gears. For example, the shaft angle of thepropeller shaft 6 is easily increased in theski boat 1. Thereduction mechanism 17 may include a plurality of conical gears having the same angle coupled to each other, or may include a plurality of conical gears having different angles coupled to each other. - In the above-described fourth embodiment also, the forward/
reverse housing 18 b, which accommodates the forward/reverse switching mechanism 20, and thereduction housing 18 c, which accommodates thereduction mechanism 17, are detachably coupled one behind the other in the axial direction of theoutput shaft 16. Since the forward/reverse switching mechanism 20 has a reduction function, the rotational speed of theinput shaft 13 differs from the rotational speed of theoutput shaft 16. Thus, in achieving commonality in the platform of thereverse gear 11 among, for example, models, thereduction mechanism 17 may have a common structure, and the forward/reverse switching mechanism 20 may be changed to one that has a desired reduction ratio. This eliminates the need for producing thereduction mechanism 17 that differs depending on models and specifications and reduces the production costs of models and specifications as a whole. Since the reduction ratio of thereduction mechanism 17 is fixed, the number of the gears constituting thereduction mechanism 17 is reduced in order to reduce the size of thereduction mechanism 17 and the space occupied by thereduction mechanism 17. This consequently reduces the size of theentire reverse gear 11 and the space occupied by theentire reverse gear 11. - Like the above-described fourth embodiment, in the above-described first embodiment and the above-described third embodiment, the idling
shaft 32 may be rotationally supported between the front end section of theoutput shaft 16 and the front end section of thepropeller shaft 6 to reduce the rotational power of theoutput shaft 16 to the fixed reduction ratio by thereduction drive gear 31, the pair of idling gears 33 and 34, and thereduction output gear 35. -
FIGS. 15 and 16 illustrate areverse gear 11 according to fifth and sixth embodiments based on the above-described third embodiment. In the fifth embodiment illustrated inFIG. 15 , theforward reduction gear 43, thereverse reduction gear 45, and theoutput gear 46 are conical gears, and theoutput shaft 16 is tilted. In the sixth embodiment illustrated inFIG. 16 , theforward reduction gear 43, thereverse reduction gear 45, and theoutput gear 46 are conical gears, and thereduction drive gear 31 and thereduction output gear 35 are spur gears. Theoutput shaft 16 is tilted to extend parallel to thepropeller shaft 6. In these embodiments, although theoutput shaft 16 is not parallel to, for example, theinput shaft 13 and is not positioned on the same plane as, for example, theinput shaft 13, there is no significant influence on reducing the height of thehousings output shaft 16 is within the range that allows theoutput shaft 16 to be fitted in thereduction housing 18 c. In the above-described fifth and sixth embodiments, theoutput shaft 16 may be a single shaft not separated in the axial direction into a front section and a rear section. - Next, a
reverse gear 11 according to a seventh embodiment will be described with reference toFIGS. 17 to 19 . Thereverse gear 11 of the seventh embodiment differs from thereverse gear 11 of the above-described fourth embodiment in the configuration of the forward/reverse switching mechanism 20. As illustrated inFIGS. 17 to 19 , thereverse gear 11 of the seventh embodiment includes theforward clutch 14 and areverse brake 61 as the forward/reverse switching mechanism 20, which shifts the rotational power of theinput shaft 13 among the forward, neutral, and reverse states. The forward/reverse switching mechanism 20 is accommodated in the forward/reverse housing 18 b. In the reverse state in which theoutput shaft 16 is rotated in reverse to theinput shaft 13, the forward/reverse switching mechanism 20 has a reduction function in which the rotational power of theinput shaft 13 is reduced and transmitted to theoutput shaft 16. - In the
reverse gear 11 of the seventh embodiment, theinput shaft 13 and theoutput shaft 16 are coaxially arranged. Theforward clutch 14 is located on the outer circumference of theoutput shaft 16, and thereverse brake 61 is located on the outer circumference of theforward clutch 14. Theforward clutch 14 is a hydraulic friction clutch and, more specifically, is a multiplate wet clutch. Thereverse brake 61 is a hydraulic friction brake and, more specifically, is a multiplate wet brake. - The
forward clutch 14 is located at an upstream section of theoutput shaft 16, which extends coaxially with theinput shaft 13, and includes thesteel plates 14 d and thefriction plates 14 e, which are alternately arranged. Theforward clutch 14 includes theforward case 14 a to which thesteel plates 14 d are attached, theforward tube 14 b, which is fixed to theforward case 14 a, and the forwardclutch cylinder 14 c, which generates contact pressure (clutch pressure) using the hydraulic oil pressure. Theforward case 14 a is fixed to theinput shaft 13. The rear end section of theoutput shaft 16 is inserted in the inner circumference of theforward case 14 a. The rear end section of theoutput shaft 16 is rotationally supported by the inner circumference of theforward case 14 a. Thefriction plates 14 e, which are capable of being brought into contact with thesteel plates 14 d under pressure, are provided on the outer circumferential portion of the rear end section of theoutput shaft 16. Theforward tube 14 b is rotationally fitted to theoutput shaft 16. Areverse drive gear 21 is integrally formed on the outer circumferential portion of the front end section of theforward tube 14 b. - The
reverse brake 61 is located on the outer circumference of the forward clutch 14 to overlap theforward clutch 14 and includes, like theforward clutch 14,steel plates 61 d andfriction plates 61 e that are alternately arranged. Thereverse brake 61 includes areverse case 61 a to whichsteel plates 61 d are attached and areverse brake cylinder 61 c. Thereverse brake cylinder 61 c generates contact pressure by the hydraulic oil pressure. Thereverse case 61 a is secured in the forward/reverse housing 18 b. Theforward case 14 a is positioned on the inner circumference of thereverse case 61 a. Thefriction plates 61 e, which are capable of being brought into contact with thesteel plates 61 d under pressure, are provided on the outer circumferential portion of a rear-facingannular projection 23 a formed on acarrier 23, which will be discussed below. Thecarrier 23 is loosely fitted to theforward tube 14 b to be rotational. - A planetary reversing
gear mechanism 22 is located on theoutput shaft 16 downstream of theforward clutch 14 and the reverse brake 61 (at a position close to the front of the rear section). The planetary reversinggear mechanism 22 includes thecarrier 23, which rotationally supports a plurality of sets ofplanetary gears 24 and reversing gears 25. As is mentioned above, thecarrier 23 is loosely fitted to theforward tube 14 b to be rotational. The group ofplanetary gears 24 are positioned on the front side of thecarrier 23 at the same radial distance from the common axis. The group of reversinggears 25 are positioned on the front side of thecarrier 23 at the same radial distance from the common axis. The radial distance between the axis and theplanetary gears 24 is different from the radial distance between the axis and the planetary gears 25. Theplanetary gears 24 of thecarrier 23 are constantly engaged with thereverse drive gear 21 of theforward tube 14 b from radially outward. Theplanetary gears 24 are also constantly engaged with the corresponding reversing gears 25. The reversing gears 25 are constantly engaged with a reverse drivengear 26. The reverse drivengear 26 is fixed to theoutput shaft 16 at a position close to the front of the rear section. - Like the above-described third to sixth embodiments, the
output shaft 16 of the seventh embodiment is separable in the axial direction into a front section and a rear section. The front and rear sections are coupled to each other with thecoupling 27 to be slidable in the axial direction and not to rotate relative to each other. The configuration of thereduction mechanism 17, which is accommodated in thereduction housing 18 c, is the same as thereduction mechanism 17 of the fourth embodiment described with reference toFIGS. 12 to 14 . - When the forward/reverse lever in the
cockpit 3 is manipulated to the forward, reverse, or neutral position, the supply destination of the hydraulic oil is shifted to the forward clutch 14 (the forwardclutch cylinder 14 c), the reverse brake 61 (thereverse brake cylinder 61 c), or neutral. - When the forward/reverse lever is manipulated to the forward position, and the
forward clutch 14 is brought into the power connected state (thesteel plates 14 d of theforward case 14 a and thefriction plates 14 e of theoutput shaft 16 are pressed together using the hydraulic oil pressure), thereverse brake 61 is in the power disconnected state. Thus, theforward clutch 14 allows theinput shaft 13 to rotate integrally with theoutput shaft 16. In this case, the rotational power of theengine 10 is transmitted from theinput shaft 13 to theoutput shaft 16 via theforward clutch 14. The rotational power transmitted to theoutput shaft 16 is transmitted to thepropeller shaft 6 via thereduction mechanism 17. As a result, thewatercraft 1 is brought into the forward state in which the rotational power of theengine 10 is transmitted to thepropeller shaft 6 as the output in the forward direction. The forward traveling speed of thewatercraft 1 during normal traveling is adjusted by the throttle lever in thecockpit 3. When theforward clutch 14 is in the power connected state, the rotation direction and the rotational speed of thereverse drive gear 21 and the reverse drivengear 26 are the same. Thus, the group of theplanetary gears 24 and the group of the reversinggears 25 do not rotate, and thecarrier 23 rotates in the same rotation direction and at the same rotational speed as theoutput shaft 16. - When the forward/reverse lever is manipulated to the reverse position, and the
reverse brake 61 is brought into the power connected state, theforward clutch 14 is in the power disconnected state, and thecarrier 23 is secured to thereverse case 61 a. Thus, the rotational power of theengine 10 is transmitted from theinput shaft 13 to theplanetary gears 24 of thecarrier 23 via thereverse drive gear 21 of theforward tube 14 b. The rotational power transmitted to theplanetary gears 24 is transmitted to the reverse drivengear 26 of theoutput shaft 16 via the reversing gears 25. Thus, theoutput shaft 16 is rotated in reverse to theinput shaft 13, and the reverse rotational power of theoutput shaft 16 is transmitted to thepropeller shaft 6 via thereduction mechanism 17. As a result, thewatercraft 1 is brought into the reverse state in which the rotational power of theengine 10 is transmitted to thepropeller shaft 6 as the output in the reverse direction. The reverse traveling speed of thewatercraft 1 during normal traveling is also adjusted by the throttle lever. In the reverse state, the rotational power of theinput shaft 13 is reduced by the forward/reverse switching mechanism 20 in accordance with the reduction ratio of the planetary reversinggear mechanism 22 and is transmitted to theoutput shaft 16. - When the forward/reverse lever is manipulated to the neutral position so that the
forward clutch 14 and thereverse brake 61 are both brought into the power disconnected state, thewatercraft 1 is brought into the neutral state in which the rotational power of theengine 10 is not transmitted to theoutput shaft 16 and thus not transmitted to thepropeller shaft 6. - In the above-described seventh embodiment, as clearly shown in the above description and
FIGS. 17 to 19 , the forward/reverse housing 18 b, which accommodates the forward/reverse switching mechanism 20, and thereduction housing 18 c, which accommodates thereduction mechanism 17, are detachably coupled one behind the other in the axial direction of theoutput shaft 16. The forward/reverse switching mechanism 20 has a reduction function so that the rotational speed of theinput shaft 13 differs from the rotational speed of theoutput shaft 16 in the reverse state, and thereduction mechanism 17 has a fixed reduction ratio. Thus, in achieving commonality of the platform of thereverse gear 11 among, for example, models, thereduction mechanism 17 may have a common structure, and the forward/reverse switching mechanism 20 may be changed to one that has a desired reduction ratio. That is, thereduction housing 18 c may be shared among different models and specifications, and thereverse gear 11 may be easily applied to a plurality of models and specifications of the watercrafts such as theski boat 1 only by developing variations of the forward/reverse housing 18 b. This eliminates the need for producing thereduction mechanism 17 that differs depending on models and specifications and thus reduces the production costs of models and specifications as a whole. - Additionally, in the above-described seventh embodiment, the
input shaft 13 and theoutput shaft 16 are coaxially arranged, theforward clutch 14 is located on the outer circumference of theoutput shaft 16, thereverse brake 61 is located on the outer circumference of theforward clutch 14, and the planetary reversinggear mechanism 22 is located on theoutput shaft 16 downstream of theforward clutch 14 and thereverse brake 61. Thus, in thereverse gear 11, the height of thehousings input shaft 13, theforward clutch 14, thereverse brake 61, and theoutput shaft 16, is reduced, and the length of thehousings reverse gear 11. This configuration improves the versatility of thereverse gear 11 and enables thereverse gear 11 to be mounted on thewatercraft 1 that has a limited height. - Additionally, in the
reverse gear 11 of the seventh embodiment, the forward/reverse switching mechanism 20 includes the output gear groups (thereverse drive gear 21, theplanetary gears 24, the reversinggears 25, and the reverse driven gear 26) in which a plurality of gears are engaged with one another. By replacing the engaged one of the gear groups (at least one of the group of thereverse drive gear 21 and theplanetary gears 24, the group of theplanetary gears 24 and the reversinggears 25, and the group of the reversinggears 25 and the reverse driven gear 26), the reduction ratio of the forward/reverse switching mechanism 20 in the reverse state is changed, and the reduction ratio of theentire reverse gear 11 in the reverse state is consequently changed. Thus, a plurality of reduction ratios can be selected by the combination of the forward/reverse switching mechanism 20 and thereduction mechanism 17 without changing the reduction ratio of thereduction mechanism 17. Thus, while achieving the commonality of thereduction mechanism 17, thelid members housings reverse gear 11 is improved. This contributes to improving the versatility and increasing the range of application of thereverse gear 11. - In the
reverse gear 11 of the seventh embodiment, the gears of the forward/reverse switching mechanism 20 may be spur gears or helical gears. -
FIGS. 20 and 21 illustrate areverse gear 11 according to an eighth embodiment based on the seventh embodiment. As illustrated inFIGS. 20 and 21 , if the conical angle of thereduction drive gear 31 and thereduction output gear 35 of thereduction mechanism 17 is greater than a certain value, the idlingshaft 32 and the pair of idling gears 33 and 34 may be omitted, and thereduction drive gear 31 and thereduction output gear 35 may be directly engaged with each other like the above-described first to third embodiments. In this manner, reducing the number of the gears constituting thereduction mechanism 17 reduces the height of thereduction housing 18 c and thereduction lid member 18 d and reduces the length of thereduction housing 18 c in the axial direction. Thus, the internal space such as the occupant's space S (refer toFIG. 1 ) is increased. This configuration provides the space for placing theseat 7 above thereduction mechanism 17 and enables thereverse gear 11 to be mounted on thewatercraft 1 that has a limited height. - Next, a
reverse gear 50 according to a reference example will be described with reference toFIGS. 22 to 25 . In thereverse gear 50 of the reference example, theinput gear 13 a, which is fixed to the front end section of theinput shaft 13, is constantly engaged with theinput relay gear 14 g, which is fixed to the rear end section of areverse output shaft 51. Thereverse output shaft 51 extends parallel to theinput shaft 13. Theinput relay gear 14 g, theforward reduction gear 43, and thereverse reduction gear 45 are provided on thereverse output shaft 51 in this order from the upstream end. Theinput relay gear 14 g is fixed to thereverse output shaft 51. Theforward reduction gear 43 is loosely fitted to thereverse output shaft 51 and is coupled by theforward clutch 14, which is a multiplate wet clutch, to be capable of connecting and disconnecting power. Thereverse reduction gear 45 is loosely fitted to thereverse output shaft 51 and is coupled by the reverse clutch 15, which is a multiplate wet clutch, to be capable of connecting and disconnecting power. Theforward reduction gear 43 is constantly engaged with aforward relay gear 53 fixed to the rear end section of aforward output shaft 52. Theforward output shaft 52 extends parallel to theinput shaft 13. Theforward clutch 14 connects or disconnects the power transmission from theinput shaft 13 to theforward output shaft 52, and the reverse clutch 15 connects or disconnects the power transmission from theinput shaft 13 to thepropeller shaft 6. The hydraulic pump 19 (refer toFIG. 25 ), which supplies hydraulic oil to theforward clutch 14 and the reverse clutch 15, is coupled to the front end section of thereverse output shaft 51. A forwardreduction drive gear 54 is fixed to the front end section of theforward output shaft 52. - The
reverse reduction gear 45, which is loosely fitted to thereverse output shaft 51, and the forwardreduction drive gear 54, which is fixed to theforward output shaft 52, are constantly engaged with thereduction output gear 35 of thepropeller shaft 6. In this reference example, theinput gear 13 a, theinput relay gear 14 g, theforward reduction gear 43, thereverse reduction gear 45, and theforward relay gear 53 are helical gears, and thereduction output gear 35 and the forwardreduction drive gear 54 are conical gears. Thegears - In the
reverse gear 50, the forward/reverse switching mechanism 20 includes theinput gear 13 a, theinput relay gear 14 g, theforward clutch 14, the reverse clutch 15, thereverse output shaft 51, theforward output shaft 52, theforward reduction gear 43, and theforward relay gear 53. Thereduction mechanism 17 includes thereduction output gear 35, thereverse reduction gear 45, and the forwardreduction drive gear 54. Thereverse reduction gear 45 and the forwardreduction drive gear 54 each configure a drive gear of thereduction output gear 35. - When the forward/reverse lever in the
cockpit 3 is manipulated to the forward, reverse, or neutral position, the supply destination of the hydraulic oil is shifted to theforward clutch 14, the reverse clutch 15, or neutral. When the forward/reverse lever is manipulated to the forward position, theforward clutch 14 is brought into the power connected state, and the reverse clutch 15 is in the power disconnected state. Thus, the forward clutch 14 causes theforward reduction gear 43 to rotate integrally with thereverse output shaft 51. In this state, the rotational power of theengine 10 is transmitted from theinput shaft 13 to theforward output shaft 52 via thereverse output shaft 51 and theforward clutch 14, and theforward output shaft 52 is rotated in the same direction as theinput shaft 13. The rotational force is transmitted from theforward output shaft 52 to thepropeller shaft 6 via thereduction mechanism 17. As a result, thewatercraft 1 is brought into the forward state in which the rotational power of theengine 10 is transmitted to thepropeller shaft 6 as the output in the forward direction. In the forward state, the rotational power of theinput shaft 13 is reduced in accordance with the reduction ratio of theinput gear 13 a and theinput relay gear 14 g, the reduction ratio of theforward reduction gear 43 and theforward relay gear 53, and the reduction ratio of the forwardreduction drive gear 54 and thereduction output gear 35. The rotational power that has been reduced is transmitted to thepropeller shaft 6. - When the forward/reverse lever is manipulated to the reverse position, the reverse clutch 15 is brought into the power connected state, and the
forward clutch 14 is in the power disconnected state. Thus, the reverse clutch 15 causes thereverse reduction gear 45 to rotate integrally with thereverse output shaft 51, which is rotated in reverse to theinput shaft 13. Thus, the rotational power of theengine 10 is transmitted from theinput shaft 13 to thepropeller shaft 6 via thereverse output shaft 51 and thereverse clutch 15. As a result, thewatercraft 1 is brought into the reverse state in which the rotational power of theengine 10 is transmitted to thepropeller shaft 6 as the output in the reverse direction. In the reverse state, the rotational power of theinput shaft 13 is reduced in accordance with the reduction ratio of theinput gear 13 a and theinput relay gear 14 g and the reduction ratio of thereverse reduction gear 45 and thereduction output gear 35 and is transmitted to thepropeller shaft 6. - When the forward/reverse lever is manipulated to the neutral position to bring both the
forward clutch 14 and the reverse clutch 15 into the power disconnected state, thewatercraft 1 is brought into the neutral state in which the rotational power is not transmitted to thepropeller shaft 6. Although both theclutches input shaft 13 is transmitted to thereverse output shaft 51 via theinput gear 13 a and theinput relay gear 14 g. Thus, thehydraulic pump 19, which is coupled to the front end section of thereverse output shaft 51, is operated. - Compared with the
reverse gear 11 of the above-described first to sixth embodiments (seven helical gears and two conical gears), the reverse gear 50 (five helical gears and two conical gears) uses a reduced number of gears. This simplifies the configuration of thereverse gear 50 and reduces the manufacturing costs. - Since both the
forward clutch 14 and the reverse clutch 15 are provided on thereverse output shaft 51, thereverse gear 50 is capable of supplying oil to theclutches reverse output shaft 51. In contrast, in thereverse gear 11 of the above-described first or second embodiment, theforward clutch 14 and the reverse clutch 15 are provided separately on the forwardclutch shaft 14 f and the reverseclutch shaft 15 f. The oil is supplied to theclutches clutch shafts reverse gear 11 of the above-described first or second embodiment (in which theclutch shafts reverse output shaft 51 includes the internal oil passage) has a reduced number of shafts that include the internal oil passage. That is, the number of shafts that use the gun drill is reduced. This simplifies the configuration of thereverse gear 50 and reduces the manufacturing costs. - Both the
forward clutch 14 and thereverse clutch 15 of thereverse gear 50 are provided on thereverse output shaft 51. The clutch cases of theclutches reverse output shaft 51. In contrast, in thereverse gear 11 of the above-described first or second embodiment, theforward case 14 a of theforward clutch 14 is shrink-fitted to the forwardclutch shaft 14 f, and thereverse case 15 a of the reverse clutch 15 is shrink-fitted to the reverseclutch shaft 15 f. Thus, the reverse gear 50 (in which the number of the shrink-fitted shaft is one) has a reduced number of the shrink-fitted shaft compared with the reverse gear 11 (the number of the shrink-fitted shaft is two) of the above-mentioned embodiments. This configuration reduces the number of processes for assembling thereverse gear 50 and reduces the manufacturing costs. - As clearly shown in the above description and
FIGS. 22 to 25 , thereverse gear 50 includes theinput shaft 13, the forward/reverse switching mechanism 20, thereverse output shaft 51, theforward output shaft 52, and thereduction mechanism 17. Theinput shaft 13 receives rotational power of theengine 10, which is the main engine. The forward/reverse switching mechanism 20 switches the rotational power of theinput shaft 13 among the forward, neutral, and reverse states. Thereverse output shaft 51 and theforward output shaft 52 output the rotational power of the forward/reverse switching mechanism 20. Thereduction mechanism 17 reduces the rotational power of theoutput shafts propeller shaft 6. Since the forward/reverse switching mechanism 20 has the reduction function, the rotational speed of theinput shaft 13 differs from the rotational speed of thereverse output shaft 51, and the rotational speed of theinput shaft 13 differs from the rotational speed of theforward output shaft 52. Thereduction mechanism 17 transmits the rotational power of theoutput shafts propeller shaft 6 by the engagement of thereverse reduction gear 45 and the forwardreduction drive gear 54, which are provided on theoutput shafts reduction output gear 35, which is provided on thepropeller shaft 6. Thus, while thereverse gear 50 obtains a desired reduction ratio by the combination of the forward/reverse switching mechanism 20 and thereduction mechanism 17, the number of the gears constituting thereduction mechanism 17 is reduced. This reduces the size of thereduction mechanism 17 and the space occupied by thereduction mechanism 17 and consequently reduces the size of theentire reverse gear 50 and the space occupied by theentire reverse gear 50. This configuration improves the versatility of thereverse gear 50 and enables thereverse gear 50 to be mounted on thewatercraft 1 that has a limited height. - In the
reverse gear 50, the height of the housing of thereduction mechanism 17 is reduced, and the length of the housing of thereduction mechanism 17 in the axial direction is reduced by reducing the number of the gears constituting thereduction mechanism 17. Thus, the space in the watercraft such as the occupant's space S (refer toFIG. 1 ) is increased. This configuration provides a space for mounting theseat 7 above thereduction mechanism 17 and enables thereverse gear 50 to be mounted on thewatercraft 1 that has a limited height. - In the
reverse gear 50, the forward/reverse switching mechanism 20 includes the input gear group (theinput gear 13 a and theinput relay gear 14 g), which includes a plurality of gears engaged with each other. The reduction ratio of the forward/reverse switching mechanism 20 is changed by replacing the input gear group. Thus, a plurality of reduction ratios can be selected by the combination of the forward/reverse switching mechanism 20 and thereduction mechanism 17 without changing the reduction ratio of thereduction mechanism 17. This configuration improves the ease in variation development of thereverse gear 50 while achieving the commonality of thereduction mechanism 17 among models and specifications and contributes to improving the versatility and increasing the range of application of thereverse gear 50. - In the
reverse gear 50, the forward/reverse switching mechanism 20 may include theforward clutch 14 and the reverse clutch 15 that have different clutch sizes from each other. For example, the clutch size of the reverse clutch 15 may be smaller than the clutch size of theforward clutch 14. Thus, the size of the forward/reverse switching mechanism 20 and the space occupied by the forward/reverse switching mechanism 20 are reduced. This consequently reduces the size of thereverse gear 50 and the space occupied by thereverse gear 50. - In the
reverse gear 50, theforward clutch 14 and the reverse clutch 15 may be swapped so that the rotational power of theinput shaft 13 is transmitted to thepropeller shaft 6 via theoutput shaft 51 as the forward output, and the rotational power of theinput shaft 13 is transmitted to thepropeller shaft 6 via theoutput shafts - The configuration of each part of the embodiments of the present invention is not limited to the illustrated embodiments, but may be modified in various forms without departing from the scope of the invention.
- For example, the
reduction mechanism 17 is not limited to a V-drive system, but may be an angle drive system or a parallel shaft system.
Claims (3)
1. A reverse gear for watercrafts comprising:
an input shaft configured to receive rotational power of a main engine;
a forward/reverse switching mechanism comprising a reduction function and configured to switch the rotational power of the input shaft among forward, neutral, and reverse states;
an output shaft configured to output the rotational power of the forward/reverse switching mechanism and to rotate at a rotational speed that differs from a rotational speed of the input shaft due to the reduction function of the forward/reverse switching mechanism;
a reduction mechanism comprising a fixed reduction ratio and configured to reduce the rotational power of the output shaft and to transmit the reduced rotational power to a propeller shaft;
a forward/reverse housing accommodating the forward/reverse switching mechanism; and
a reduction housing accommodating the reduction mechanism, the forward/reverse housing and the reduction housing are detachably coupled one behind the other in an axial direction of the output shaft.
2. The reverse gear for watercrafts according to claim 1 , wherein the forward/reverse switching mechanism comprises at least one of an input gear group and an output gear group, the input gear group and the output gear group each comprises a plurality of gears engaged with one another, and the forward/reverse switching mechanism comprises a reduction ratio that is changed by replacing at least one of the input gear group and the output gear group.
3. The reverse gear for watercrafts according to claim 1 , wherein the forward/reverse switching mechanism comprises a forward clutch and a reverse clutch that differ in a clutch size from each other.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2016-187427 | 2016-09-26 | ||
JP2016187427A JP2018053936A (en) | 2016-09-26 | 2016-09-26 | Speed reduction reversal machine and ship provided with this machine |
Publications (1)
Publication Number | Publication Date |
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US20180086428A1 true US20180086428A1 (en) | 2018-03-29 |
Family
ID=61687598
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US15/715,667 Abandoned US20180086428A1 (en) | 2016-09-26 | 2017-09-26 | Reverse gear |
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US (1) | US20180086428A1 (en) |
JP (1) | JP2018053936A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170284511A1 (en) * | 2016-04-05 | 2017-10-05 | Kanzaki Kokyukoki Mfg. Co., Ltd. | Reduction reverse gear and ship including the same |
DE102022206009B3 (en) | 2022-06-14 | 2023-11-30 | Zf Friedrichshafen Ag | Marine gearbox |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20220289355A1 (en) * | 2019-08-08 | 2022-09-15 | Kanzaki Kokyukoki Manufacturing Co., Ltd. | Marine propulsion apparatus |
JP7359419B2 (en) * | 2019-08-08 | 2023-10-11 | 株式会社 神崎高級工機製作所 | Reduction/reversing machine |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
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US1667842A (en) * | 1925-07-09 | 1928-05-01 | Thomas C Coykendall | System of marine propulsion |
US1701403A (en) * | 1924-12-20 | 1929-02-05 | Thomas C Coykendall | System of marine propulsion |
US2130125A (en) * | 1937-04-02 | 1938-09-13 | Chrysler Corp | Boat propelling apparatus |
US2568275A (en) * | 1948-11-24 | 1951-09-18 | Josef Y Dahlstrand | Power transmission unit |
US3636796A (en) * | 1969-12-18 | 1972-01-25 | Gen Motors Corp | Change-speed drive axle |
-
2016
- 2016-09-26 JP JP2016187427A patent/JP2018053936A/en active Pending
-
2017
- 2017-09-26 US US15/715,667 patent/US20180086428A1/en not_active Abandoned
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1701403A (en) * | 1924-12-20 | 1929-02-05 | Thomas C Coykendall | System of marine propulsion |
US1667842A (en) * | 1925-07-09 | 1928-05-01 | Thomas C Coykendall | System of marine propulsion |
US2130125A (en) * | 1937-04-02 | 1938-09-13 | Chrysler Corp | Boat propelling apparatus |
US2568275A (en) * | 1948-11-24 | 1951-09-18 | Josef Y Dahlstrand | Power transmission unit |
US3636796A (en) * | 1969-12-18 | 1972-01-25 | Gen Motors Corp | Change-speed drive axle |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170284511A1 (en) * | 2016-04-05 | 2017-10-05 | Kanzaki Kokyukoki Mfg. Co., Ltd. | Reduction reverse gear and ship including the same |
US10604223B2 (en) * | 2016-04-05 | 2020-03-31 | Kanzaki Kokyukoki Manufacturing Co., Ltd. | Reduction reverse gear and ship including the same |
DE102022206009B3 (en) | 2022-06-14 | 2023-11-30 | Zf Friedrichshafen Ag | Marine gearbox |
Also Published As
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JP2018053936A (en) | 2018-04-05 |
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