Embodiments of marine reduction and reverse gear units according to the present invention are described below with reference to the attached drawings. In all of the drawings, the same reference numerals denote the same constitutional elements.
First, a first embodiment of a marine reduction and reverse gear unit according to the present invention is described with reference to
The marine reduction and reverse gear unit 1 is provided with a casing 2. The casing 2 is fixed on a housing 5 in which components such as a flywheel 4 connected to a rotary shaft 3 of an engine E (
A drive gear 15 is fixed on the input shaft 7, and a reverse gear 16 is rotatably supported by the input shaft 7. A reverse hydraulic clutch 17 for connecting the drive gear 15 and reverse gear 16 is also disposed on the input shaft 7 and located between the drive gear 15 and reverse gear 16. The reverse hydraulic clutch 17 is a known wet multiplate clutch. A plurality of clutch discs are fixed on an inner drum integrally formed with the reverse gear 16, and each of a plurality of pressure plates fixed on an outer drum integrally formed with the drive gear 15 are inserted into each space between the plurality of the clutch discs. These discs and plates are brought into tight contact with each other by the pressing force of a hydraulic piston to thereby transmit driving force.
The reverse gear 16 is engaged with a first idle gear 21 fixed on an idle shaft 20. The idle shaft 20 is rotatably supported by a casing 2. A second idle gear 22 is also fixed on the idle shaft 20 and located at a distance from the first idle gear 21 toward the bow of the boat. The second idle gear 22 is engaged with an output gear 26 fixed on an output shaft 25. A propeller P (
A first driven gear 30 and a second driven gear 31 are disposed on the right and left sides of the drive gear 15 in such a manner that the drive gear 15 is sandwiched between the first and second driven gears 30, 31. The first driven gear 30 and the second driven gear 31 are engaged with the drive gear 15.
The first driven gear 30 is fixed on a first support shaft 35. The first support shaft 35 is rotatably supported by the casing 2 and disposed parallel to the input shaft 7. A first forward speed gear 33 engaged with a first idle gear 21 is rotatably supported by the first support shaft 35 and disposed at a distance from the first driven gear 30. A first forward speed hydraulic clutch 37 for connecting the first driven gear 30 and first forward speed gear 33 is also disposed on the first support shaft 35 and located between the first driven gear 30 and the first forward speed gear 33. The first forward speed hydraulic clutch 37 is a wet multiplate clutch as used for the reverse hydraulic clutch 17.
The second driven gear 31 is fixed on a second support shaft 32. The second support shaft 32 is rotatably supported by the casing 2 and disposed parallel to the input shaft 7. A second forward speed gear 36 engaged with a first idle gear 21 is rotatably supported by the second support shaft 32 and disposed at a distance from the second driven gear 31. A second forward speed hydraulic clutch 34 for connecting the second driven gear 31 and second forward speed gear 36 is also disposed on the second support shaft 32 and located between the second driven gear 31 and the second forward speed gear 36. The second forward speed hydraulic clutch 34 is a wet multiplate clutch as used for the reverse hydraulic clutch 17.
By making the diameter of the first forward speed gear 33 smaller than that of the second forward speed gear 36, the speed reducing ratio provided by the first forward speed gear 33 and the first idle gear 21 is made greater than that provided by the second forward speed gear 36 and the first idle gear 21.
The first and second support shafts 35, 32 constantly rotate with respect to the input shaft 7 via the drive gear 15, and the first and second driven gears 30, 31, respectively. According to this embodiment, a gear pump 10 (
The marine reduction and reverse gear 1 having the above configuration transmits driving force from an engine E (see
In reverse drive, rotation of the input shaft 7 is transmitted to the output shaft 25 via the drive gear 15, reverse hydraulic clutch 17, reverse gear 16, first idle gear 21, second idle gear 22, and output gear 26.
By shifting from reverse drive to first forward speed drive, the reverse hydraulic clutch 17 is disengaged and the first forward speed hydraulic clutch 37 is engaged, so that the rotation of the input shaft 7 is transmitted to the output shaft 25 via the drive gear 15, first driven gear 30, first forward speed gear 33, first idle gear 21, second idle gear 22, and output gear 26 to achieve a high reduction ratio.
By shifting from first forward speed drive to second forward speed drive, the first forward speed hydraulic clutch 37 is disengaged and the second forward speed hydraulic clutch 34 is engaged, so that the rotation of the input shaft 7 is transmitted to the output shaft 25 via the drive gear 15, second driven gear 31, second forward speed gear 36, first idle gear 21, second idle gear 22, and output gear 26 to achieve a low reduction ratio, compared with a high reduction ratio achieved with the first forward speed drive.
A first embodiment of a hydraulic circuit for controlling the reverse hydraulic clutch 17, first forward speed hydraulic clutch 37, and second forward speed hydraulic clutch 34 is described below with reference to
A gear pump 10 on a second support shaft 32 is driven by rotation of an input shaft 7. The gear pump 10 draws oil from an oil sump 40 in the casing 2 via an oil filter 41, and discharges the oil. The hydraulic oil discharged from the gear pump 10 is supplied to the reverse hydraulic clutch 17 via a forward/reverse directional control valve 42 or supplied to the first forward speed hydraulic clutch 37 or second forward speed hydraulic clutch 34 via a forward/reverse directional control valve 42 and an electromagnetic shift control valve 46.
In the embodiment illustrated, the forward/reverse directional control valve 42 is a manual 5-port, 3-position directional control valve. The forward/reverse directional control valve 42 can be connected to a shift lever 42a in the vessel by a wire cable (not shown).
The hydraulic circuit is provided with a relief valve 47 having a soft engagement function to reduce the impact of abrupt engagement by clutches 17, 34, and 37. The relief valve 47 comprises a pressure-control spring 48 and a spring bearing 49 in the form of a hydraulic piston, which is capable of compressing the pressure-control spring 48 and disposed in a cylinder (not shown). The hydraulic circuit includes a pressure control circuit formed by connecting a throttling passage branched from a forward output port and a reverse output port of the forward/reverse directional control valve 42 to an oil chamber in the spring bearing 49. When the forward/reverse directional control valve 42 is in the neutral position (as in
The oil passed through the relief valve 47 is cooled with an oil cooler 50, and then passed through a lubricant oil passage 51. The set pressure of the lubricant oil passage 51 is controlled by a relief valve 52.
According to the first embodiment of the hydraulic circuit, the boat is run at a normal speed by shifting the forward/reverse switching valve 42 to the forward or reverse position. During normal-speed running, the electromagnetic shift control valve 46 is not excited and is positioned as shown in
Next, a second embodiment of a hydraulic circuit is described below with reference to
The shift control valve 46a shown in
As the number of rotations of the input shaft 7 increases by increasing the number of engine revolutions, the number of rotations of the gear pump 10 increases, thereby increasing the pilot pressure, i.e., the pressure of oil running through the primary oil passage 56, and shifting the directional control valve 46a to the right side of
Since the hydraulic circuit according to the second embodiment operates in the above-described manner, the following effects can be achieved. When wakeboarding, where the boat runs at a comparatively low speed with added ballast water to increase the tare weight, the number of engine revolutions is increased to automatically engage the first forward speed hydraulic clutch 37 and make a high torque range available, thereby providing a stable boat speed and enhanced acceleration performance. When not wakeboarding, where the boat runs at a normal speed, the number of engine revolutions is reduced to automatically disengage the first forward speed hydraulic clutch 37 and engage the second forward speed hydraulic clutch 34, thereby achieving stable running. Thus the operator is free from the need to perform complicated clutch shift operations, and does not have to be conscious thereof when running the boat.
Next, a third embodiment of a hydraulic circuit is described with reference to
The third embodiment of the hydraulic circuit is the same as the second embodiment in that the shift control valve 46b is a pilot-operated spring-return 3-position directional control valve using the primary pressure as pilot pressure.
However, the shift control valve 46b shown in
Other differences from the hydraulic circuit of
According to the third embodiment of the hydraulic circuit having the above configuration, when the shift control valve 46b is in the center position at the time of shifting from forward first speed to second forward speed, hydraulic oil is temporarily supplied to both the first forward speed hydraulic clutch 37 and the second forward speed hydraulic clutch 34. As a result, there is no temporal decrease in the number of rotations of the output shaft as indicated by the broken line in the graph of
In the embodiment illustrated, the pilot oil passage 57 is provided with a variable throttle valve 58, and the return spring 55 is provided with a spring force adjustment mechanism 55a. However, since these components are to adjust the timing of shifting between first forward speed and second forward speed, either one of the components may be used. It is also possible to use a variable flow-control valve in place of the variable throttle valve 58.
Next, a second embodiment of a marine reduction and reverse gear according to the present invention is described with reference to
As shown in
A first driven gear 30a and a second driven gear 31a are disposed on the right and left sides of the driven gear 15a to sandwich the driven gear 15a between the first and second driven gears 30a, 31a. The first driven gear 30a and the second driven gear 31a are engaged with the drive gear 15a.
The first driven gear 30a is fixed on a first support shaft 35a. The first support shaft 35a is rotatably supported by the casing 2a and disposed parallel to the third support shaft 61. A forward first gear 33a engaged with an output gear 26a is rotatably supported by the first support shaft 35a and disposed at a distance from the first driven gear 30a toward the bow of the boat. A first forward speed hydraulic clutch (not shown) for connecting the first driven gear 30a and the first forward speed gear 33a is also disposed on the first support shaft 35a and located between the first driven gear 30a and the first forward speed gear 33a.
The second driven gear 31a is fixed on a second support shaft 32a. The second support shaft 32a is rotatably supported by the casing 2a and disposed parallel to the third support shaft 61. A second forward speed gear 36a engaged with an output gear 26a is rotatably supported by the second support shaft 32a and disposed at a distance from the second driven gear 31a. A second forward speed hydraulic clutch (not shown) for connecting the second driven gear 31a and the second forward speed gear 36a is also disposed on the second support shaft 32a and located between the second driven gear 31a and the second forward speed gear 36a.
The input shaft of the marine reduction and reverse gear unit according to the second embodiment is shorter than the input shaft according to the first embodiment. This downsizing can provide more space above the casing 2. The hydraulic circuit may be the same as in the first embodiment.
Next, a third embodiment of a marine reduction and reverse gear unit according to the present invention is described with reference to
The third embodiment is a modification of the first embodiment to an angle-drive marine reduction and reverse gear unit in which the idle shaft is omitted from the first embodiment.
In reverse drive, engine revolution is transmitted to an output shaft 25b via the following components: an elastic coupling 6; an input shaft 7b; a drive gear 15b fixed on an input shaft 7b; a reverse hydraulic clutch 17b; a reverse gear 16b rotatably supported by the input shaft 7b; and an output gear 26b.
In first forward speed drive, engine revolution is transmitted to the output shaft 25b via the following components: the elastic coupling 6; the input shaft 7b; the drive gear 15b fixed on the input shaft 7b; a first driven gear 30b fixed on a first support shaft 35b and engaged with the driven gear 15b; a first forward speed hydraulic clutch 37b; a first forward speed gear 33b; and the output gear 26b.
In second forward speed drive, engine revolution is transmitted to the output shaft 25b via the following components: the elastic coupling 6; the input shaft 7b; the drive gear 15b fixed on the input shaft 7b; a second driven gear 31b fixed on a second support shaft 32b and engaged with the driven gear 15b; a second forward speed hydraulic clutch 34b; a second forward speed gear 36b; and the output gear 26b.
Next, a fourth embodiment of a marine reduction and reverse gear unit according to the present invention is described with reference to
In reverse drive, engine revolution is transmitted to an output shaft 25c via the following components: an elastic coupling 6; an input shaft 7c; a bevel gear 60; a gear 62; a drive gear 15c; a reverse hydraulic clutch 17c; a reverse gear 16c; and an output gear 26.
In first forward speed drive, engine revolution is transmitted to the output shaft 25c via the following components: the elastic coupling 6; the input shaft 7c; the bevel gear 60; the gear 62; the drive gear 15c; a first driven gear 30c fixed on a first support shaft 35c; a first forward speed hydraulic clutch 37c; a first forward speed gear 33c supported by the first support shaft 35c; and the output gear 26c.
In second forward speed drive, engine revolution is transmitted to the output shaft 25c via the following components: the elastic coupling 6; the input shaft 7c; the bevel gear 60; the gear 62; the drive gear 15c; a second driven gear 31c fixed on a second support shaft 32c; a second forward speed hydraulic clutch 34c; a second forward speed gear 36c supported by the second support shaft 32c; and the output gear 26c.
In the fourth embodiment, the gear 62 may be omitted and the drive gear 15c may be engaged with the bevel gear 60 as in the second embodiment.
Number | Date | Country | Kind |
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2006-201714 | Jul 2006 | JP | national |