CA1081005A - Two-speed transmission - Google Patents
Two-speed transmissionInfo
- Publication number
- CA1081005A CA1081005A CA283,047A CA283047A CA1081005A CA 1081005 A CA1081005 A CA 1081005A CA 283047 A CA283047 A CA 283047A CA 1081005 A CA1081005 A CA 1081005A
- Authority
- CA
- Canada
- Prior art keywords
- drive
- gear
- input shaft
- 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.)
- Expired
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- Control Of Transmission Device (AREA)
- Structure Of Transmissions (AREA)
- One-Way And Automatic Clutches, And Combinations Of Different Clutches (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Disclosed herein is a marine propusion device incorporating a two-speed transmission including a first drive gear which is mounted for common rotation with an input shaft drivingly connected to an engine and which meshes with first driven gear mounted for rotation coaxially with a drive shaft drivingly connected to the propeller shaft and further including a second drive gear ratio of the first drive and driven gears. The second
Disclosed herein is a marine propusion device incorporating a two-speed transmission including a first drive gear which is mounted for common rotation with an input shaft drivingly connected to an engine and which meshes with first driven gear mounted for rotation coaxially with a drive shaft drivingly connected to the propeller shaft and further including a second drive gear ratio of the first drive and driven gears. The second
Description
TITLE
TWO-SPEED TRANSMISSION
INVENTOR
Charles D. Strang BACKGROUND OF THE INVE~TION
The invention relates to transmissions and, more particularly, to two-speed transmissions for marine pro-pulsion devices and the like.
The thrust requirement curve (thrust vs. speed) for planing boats propelled by an outboard motor or a stern drive propulsion unit has a marked hump at the point where the boat is starting to plane. The propeller ordinarily must absorb full engine power at rated engine r.p.m. and maximum boat speed. A conventional size propeller normally limits the r.p.m. during this critical time, thereby limiting the thrust developed. If the pro-peller is designed to permit the boat to "go over the hump"
under relatively high load conditions, such as when water skiers are being towed, it will permit the engine to run at excessive speeds once the boat is planing and less power is r~quired to drive the propeller.
This problem could be alleviated by using a pro-peller having an adjustable pitch; however, many years of development have failed to produce a practical and efficient adjustable pitch propeller.
Also, it is desirable for propulsion units used in racing boats to have a transmission which permits the boat engine to rapidly turn up to a full speed when accelerating out of a turn and then shift automatically to facilitate full speed operation after the boat is planing.
~ 5 SU~ARY O~ T~IE INVENTION -The invention provides a marine propulsion device comprising an input shaft drivingly connected to a power source, a lower unit having a rotatably mounted drive shaft, a propeller shaft rotatably mounted in the lower unit and carrying a propeller, means drivingly connecting the drive shaft to the propeller shaft, and a two-speed transmission drivingly connecting t'ne input shaft to the drive shaft and including first drive means between the input shaft and the drive shaft for selectively drivingly connecting the input shaft and the drive shaft at all input speeds and including a drive gear, a driven gear in meshing engagement with the drive gear, and a one-way overrunning clutch drivingly connecting the input shaft and the drive shaft through the drive and driven gears when the rotational speed of the input shaft is less than a predetermined value, which first drive means has an input-output speed ratio with a first valueJ and second drive means for selectively drivingly connecting the input shaft and the drive shaft when the rotational speed of the input shaft is greater than the predetermined value, which second drive means includes a selectively actuatable clutch for drivingly connecting the input shat and the drive shaft, and which second drive means has an input-output speed ratio with a second value greater than the first value.
In accordance with one embodiment, the input shaft and the drive shaft are axially offset.
In accordance with one embodiment, the second drive means includes a second drive gear and a second driven gear in meshing engagement with the second drive gear.
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....
, . .
': . .' ' . : ' .' :
In accordance with one embodiment, the second drive means clutch comprises a centrifugal clutch inc~uding a drum drivingly connected to one of the input shaft and the drive shaft and a drive~ drivingly connected to the other of the input shaft and the drive shaft and operable in response to driver rotation above a predetermined speed to effect driving engagement between the driver and khe drum and therefore between the input shaft and the drive shaft.
In accordance with one embodiment, the marine propulsion device further includes a second drive shaft rotatably mounted in the lower unit and drivingly connected to the propeller shaft, and means adjacent the first and second drive means for drivingly connecting the first mentioned drive shaft to the second drive shaft for transmissions of power to the propeller shaft through the first mentioned and second drive shaft.
One of the principal features of the invention is the provision of a marine propulsion device including a simple two-speed transmission which can be conveniently shifted to a higher gear ratio.
Another of the principal features of the invention is the provision of a marine propulsion device including a two-speed transmission which is arranged to prevent engine overspeeding at full throttle and maximum speeds of a planing boat.
Another of the principal features of the invention is the provision of such a marine propulsion device including such a transmission which automatically shifts between two different gear ratios at a predetermined engine speed.
Other features and advantages of the invention will become apparent upon reviewing the fol-lowing detailed descriptiGn, the drawing, and the appended claims.
BRI~F DESCRIPTION OF THE DRAWINGS
Fig. 1 is a side elevational view, partially broken away and partially in section, of an outboard motor embodying various of the features of the invention.
Fig. 2 is a side elevational view, partially broken away and partially in section, of another embodiment of an outboard motor embodying various of the features of the invention.
Before explaining preferred embodiments of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or iilustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it should be understood that the phraseology and terminology employed herein is for the purposes of description and should not be .
~ -~ 5 regarded as limiting.
DESCRIPTION OF THE PREFERRED E~IBODIMENTS
-Illustrated in ~ig. 1 is a marine propulsion device, such as an outboard motor 10, including a power S head 12 which houses an internal combustion engine 14 and a lower unit 16 having a gear box 18. Rotatably mounted in the gear box 18 is a propeller shaft 20 carrying a pro-peller 22 on the outer end. Located within the gear box 18 is a pair of facing, axially-spaced gears 24 and 26 which are carried by and are drivingly connected to the ~ropeller shaft 20. Extending through the lower unit 16 is a rotatably mounted drive shaft 28 carrying a lower bevel gear 30 which meshes with ~he gears 24 and 26. The drive shaft 28 is drivingly connected to the engine 14 through a two-speed transmission, designated generally by the reference numeral 32.
The transmission 32 includes an input shaft 34 which is rotatably mounted such as by a bearing 35 and is drivingly connected to the engine 14, a first drive gear 36 carried by and mounted for common rotation with the input shaft 34, and a second drive gear 38 mounted for rotation coaxially with and independently of the input shaft 34.
The transmission 32 also includes a first driven gear 40 which meshes with the first drive gear 3~ and is mounted for rotation coaxially with the drive shaft 28 and a second driven gear 42 which meshes with the second drive gPar 38 and is mounted for common rotation with the drive shaft 28.
For reasons explained below, the gear ratio of the second drive gear 38 to the second driven gear 42 is greater than the gear ratio of the first drive gear 36 to the first driven gear 40.
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The first driven gear 40 is drivingly connec~ed to the drive shaft 28 by a suitable one-way, overrunning clutch means 44 disposed therebetween. The one-way clutch means 44 is constructed in the conventional manner so a detailed description of its structural features and mode of operation is not necessary for full understanding of the invention. Generally, the one-way clutch means 44 is arranged so that, in response to rotation o the first driven gear 40 via the first drive gear 36 and the input -shaft 34, it drives the drive shaft 28 in one rotary direc-tion. Further, the one-way clutch means 44 is arranged so that, when the rotational speed of the drive shaft 28 in the one rotary direction exceeds the rotational speed of the first drive gear 40 in the same rotary direction (i.e., when the drive shaft 28 overruns the first driven gear 40), the drive shaft 28 becomes free wheeling relative to the first driven gear 40.
For example, the one-way clutch means 44 can include teeth or lugs (not shown) which are drivingly connected to the first driven gear 40, which are biased into driving engagement with complementary teeth or lugs (not shown~ provided on the drive shaft 28, and which are disengaged from the drive shaft teeth or lugs when over-running occurs.
Carried on the input shaft 34 is a centrifugal clutch which is operable, in response to rotation of the in-put shaft 34 above a predetermined speed, to drivingly connect the second drive gear 38 to the input sha~t 34.
While various arrangements can be used, in the specific construction illustrated, there is provided a centrifugal clutch 46 including a clutch drum ~8 which has a cylindrical inner surface 50 and is mounted for common . .
- . - .. .. . . : , . . . ............. .
rotation with the input sha~t 34. The clutch 46 also has two or more clutch shoes 52 carried by a clutch shoe driver 54 which is drivingly connected ~o the second drive gear 38 and is mounted for rotation coaxially with and independently of the input shaft 34. The clutch shoe driver 54 rotates the clutch shoes 52, in response to rotation o~ the second drive gear 38, and is arranged in a suitable manner to cause the clutch shoes 52 to move radially between an inner or retracted position spaced from the clutch drum 48 and an outer or extended position in driving engagement with the clutch drum inner surface 50 when the second drive gear 38 is rotated a~ a speed corresponding to the predetermined input shaft speed.
The clutch shoes 52 can be constructed in any suitable manner including an arcuate surface adapted to drivingly engage the inner surface 50 of the clutch drum 48 when the clutch shoe driver 54 is rotated at a speed cor-responding to the predetermined input shaft speed. Outward movement of the clutch shoes 52 from the retracted positlon, in absence of rotation of the clutch shoe driver above the predetermined speed, is restrained by a suitable means (not shown). ~:
In operation, when the input shaft 34 is being rotated at low or moderate speeds, the drive sha~t 28, and thus the propeller 22, is driven by the input shaft 34 via the first drive gear 36, the first driven gear 40, and the ;:
one-way clutch means 44. The second drive gear 38 is also being driven by the second driven gear 40 at this time but is free wheeling relative to the input sha~t 34 because the :
clutch shoe driver 54 is being rotated at a speed less than the predetermined speed at which the clutch shoes 52 are moved radially outwardly to the extended position.
l~en the engine speed is increased to a point where the clutch shoe driver 54 is rotated above the predetermined speed, the clutch shoes 52 drivingly engage the inner surface 50 of the clutch drum 48 to drivingly connect the second drive gear 38 to the input shaft 34. -The second drive gear 38 thereafter drives the second driven gear 42.
Since the gear ratio between the second drive gear 38 and the second driven gear 42 is greater than the gear ratio between the first drive gear 36 and the first driven gear 40, the drive shaft 28 is rotated at a rate faster than the rate of rotation of the first driven gear 40, causing the one-way clutch means 44 to disengage so that the drive shaft 28 is free wheeling reIative to the first driven gear 40. The drive shaft 28 thereafter is driven by the input shaft 34 via the centrifugal clutch 46, the second drive gear 38 and the second driven gear 42.
When the engine speed is decreased to a point where the rate of rotation of the clutch shoe driver 54 falls below the predetermined speed, the clutch shoes 52 return toward the retracted position (i.e., disengage ~rom the clutch drum 48), thereby disconnecting the second drive gear 38 from the input shaft 34 and causing a reduction in the rate of rotation of the drive shaft 28 to a speed where the one-way clutch means 44 re-engages. The drive shaft 28 thereafter is driven by the input shaft 34 via the first drive gear 36, the first driven gear 40, and the one-way clutch means 44.
With this arrangement, a relative large propeller can be used to develop sufficient thrust to get the boat to "go over the hump" on the thrust vs. speed curve with large boat loads or while towing skiers and yet the engine will - - . . . .. . . ~ . . :
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not overspeed at ~ull throttle and maximum boat speed after the boat is planing. That is, the engine 14 can be operated at a high speed while rotating the propeller 22 at a low speed via the input shaft 34, the first drive gear 36, the first driven gear 40, and the one-way clutch means 44, to develop su~ficient power or thrust to get the boat "over the hump." Once the boat is planing and less engine power is required to rotate the propeller 22 at maximum speed, the transmission 32 shi~ts, via the centrifugal clutch 46, to the higher gear ratio provided by the second drive gear 38 and the second driven gear 42, thereby preventing the engine 14 from overspeeding at full throttle and maximum boat speed. Thus, smaller, more economical engines can be used for carrying heavy loads or towing water skiers, which tasks normally require larger engines to get the boat "over the hump" and into planing trim.
Further, the two-speed transmission 32 can be advantageously used in propulsion units for racing boats. ~
The transmission permits the engine to rapidly turn up to ~;
higher r.p.m.'s while accelerating out of a turn and then shifts, after the boat is planing, to facilitate top speed operation. When a centrifugal clutch is employed as in the embodiment illustrated in Fig. 1, this shifting is accomplished automatically without any effort on the part of the driver and higher lap speeds normally can be obtained for a given engine.
Fig. 2 illustrates another embodiment of the invention including various components which are constructed and arranged in a manner similar to the embodiment illus- - -trated in Fig. 1. Thus, the same reference numerals have been assigned to common components. -;- . . .. . , ., . . . . ~. . , . . - : . ,.
The basic difference between the marine pro-pulsion unit 60 shown in Fig. 2 and the marine propulsion unit 10 shown in Fig. 1 is that the former employs dual drive shafts instead of a single drive shaft. The use of dual drive shafts affords the use of smaller drive gears to impart the same power to the propeller and ~hus less frontal area for the gear case 18 and/or smaller size of the portion of the housing enclosing the upper end of the drive shafts.
Located within the gear box 18 and dri~ingly connected to the propeller sha~t 20 are a pair of bevel gears 62 which can be a unitary element as illustrated or separate gears. Extending through the lower unit 16 is a first rotatably mounted drive shaft 64 which is similar to the drive shaft 28 in Fig. 1 and carries a lower bevel gear 66 which meshes with one of the gears 62. Extending through the lower unit 16 in parallel relationship to the first drive shaft 64 in a second rotatably mounted drive shaft 68 carrying a lower bevel gear 70 which meshes with the other of the gears 62. The first and second drive shafts 64 and 68 are drivingly connected to the engine by a two-speed transmission 32a which is constructed and operates in the same basic manner as the transmission 32 in Fig. 1, except that the second driven gear 42a, in addi-tion to meshing with the second drive gear 38, also meshes with a third driven gear 72 mounted on the upper end of the second drive shaft 68 for common rotation therewith.
In operation, when the input shaft 34 is being rotated at low or moderate speeds, the first drive shaft 64 is driven by the input shaft 34 via the first drive gear 36, the first driven gear 40, and the one-way clutch means 44.
The second drive shaft 68 is driven by the input shaft 34 via the first drive gear 36, the first driven gear 40, the one-way clutch means 44, the second driven gear 42a and the third driven gear 72 to effect counter rotation of the drive shafts 64 and 68 and the gears 66 and 70. The second drive gear 38 is also being driven by the second driven gear 42a at the same time but is free wheeling relative to the input shaft 34 because the clutch shoe driver 54 is being rotated at a speed less than the speed at which the clutch shoes 52 are moved radially outwardly to an extended position.
When the engine speed is increased to a point where the clutch shoe driver 54 is rotated above the pre-determined speed, the clutch shoes 52 engage the clutch drum 48 to drivingly connect the second drive gear 38 to the input shaft 34, causing the transmission 32a to shift ~ .
as described above. The drive shafts 64 and 68 thereafter are driven by the input shaft 34 via the centrifugal clutch .
46, the second drive gear 38 and the respec~ive second :
driven gear 42a and third driven gear 72. When the engine speed is decreased, the transmission shifts back to the lower gear ratio as described above. :~
While a centrifugal clutch has been illustrated and described, and generally is preferred because automatic shifting is afforded, it is within the scope of the invention to employ a suitable manually shiftable clutch for selectively . :~.
connecting the second driven gear 38 to the input shaft 34.
Although the two-speed transmission of ~he invention has been described for use on an outboard motor, it should be understood that it can be used in other marine propulsion ~
devices, such as stern drive units, and in other similar .
applications. .
Further, while the transmission has been illustrated and described as being located in the powerhead, immediately -11- .
below the engine and above the drive shaft and on ~he top of the drive shaft housing, it can be located in the lower unit above the gear box, such as in the lower end portion of the drive shaft housing connected to the gear box.
Various of the features of the inventlon are set forth in the following claims:
TWO-SPEED TRANSMISSION
INVENTOR
Charles D. Strang BACKGROUND OF THE INVE~TION
The invention relates to transmissions and, more particularly, to two-speed transmissions for marine pro-pulsion devices and the like.
The thrust requirement curve (thrust vs. speed) for planing boats propelled by an outboard motor or a stern drive propulsion unit has a marked hump at the point where the boat is starting to plane. The propeller ordinarily must absorb full engine power at rated engine r.p.m. and maximum boat speed. A conventional size propeller normally limits the r.p.m. during this critical time, thereby limiting the thrust developed. If the pro-peller is designed to permit the boat to "go over the hump"
under relatively high load conditions, such as when water skiers are being towed, it will permit the engine to run at excessive speeds once the boat is planing and less power is r~quired to drive the propeller.
This problem could be alleviated by using a pro-peller having an adjustable pitch; however, many years of development have failed to produce a practical and efficient adjustable pitch propeller.
Also, it is desirable for propulsion units used in racing boats to have a transmission which permits the boat engine to rapidly turn up to a full speed when accelerating out of a turn and then shift automatically to facilitate full speed operation after the boat is planing.
~ 5 SU~ARY O~ T~IE INVENTION -The invention provides a marine propulsion device comprising an input shaft drivingly connected to a power source, a lower unit having a rotatably mounted drive shaft, a propeller shaft rotatably mounted in the lower unit and carrying a propeller, means drivingly connecting the drive shaft to the propeller shaft, and a two-speed transmission drivingly connecting t'ne input shaft to the drive shaft and including first drive means between the input shaft and the drive shaft for selectively drivingly connecting the input shaft and the drive shaft at all input speeds and including a drive gear, a driven gear in meshing engagement with the drive gear, and a one-way overrunning clutch drivingly connecting the input shaft and the drive shaft through the drive and driven gears when the rotational speed of the input shaft is less than a predetermined value, which first drive means has an input-output speed ratio with a first valueJ and second drive means for selectively drivingly connecting the input shaft and the drive shaft when the rotational speed of the input shaft is greater than the predetermined value, which second drive means includes a selectively actuatable clutch for drivingly connecting the input shat and the drive shaft, and which second drive means has an input-output speed ratio with a second value greater than the first value.
In accordance with one embodiment, the input shaft and the drive shaft are axially offset.
In accordance with one embodiment, the second drive means includes a second drive gear and a second driven gear in meshing engagement with the second drive gear.
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. . .
....
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': . .' ' . : ' .' :
In accordance with one embodiment, the second drive means clutch comprises a centrifugal clutch inc~uding a drum drivingly connected to one of the input shaft and the drive shaft and a drive~ drivingly connected to the other of the input shaft and the drive shaft and operable in response to driver rotation above a predetermined speed to effect driving engagement between the driver and khe drum and therefore between the input shaft and the drive shaft.
In accordance with one embodiment, the marine propulsion device further includes a second drive shaft rotatably mounted in the lower unit and drivingly connected to the propeller shaft, and means adjacent the first and second drive means for drivingly connecting the first mentioned drive shaft to the second drive shaft for transmissions of power to the propeller shaft through the first mentioned and second drive shaft.
One of the principal features of the invention is the provision of a marine propulsion device including a simple two-speed transmission which can be conveniently shifted to a higher gear ratio.
Another of the principal features of the invention is the provision of a marine propulsion device including a two-speed transmission which is arranged to prevent engine overspeeding at full throttle and maximum speeds of a planing boat.
Another of the principal features of the invention is the provision of such a marine propulsion device including such a transmission which automatically shifts between two different gear ratios at a predetermined engine speed.
Other features and advantages of the invention will become apparent upon reviewing the fol-lowing detailed descriptiGn, the drawing, and the appended claims.
BRI~F DESCRIPTION OF THE DRAWINGS
Fig. 1 is a side elevational view, partially broken away and partially in section, of an outboard motor embodying various of the features of the invention.
Fig. 2 is a side elevational view, partially broken away and partially in section, of another embodiment of an outboard motor embodying various of the features of the invention.
Before explaining preferred embodiments of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or iilustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it should be understood that the phraseology and terminology employed herein is for the purposes of description and should not be .
~ -~ 5 regarded as limiting.
DESCRIPTION OF THE PREFERRED E~IBODIMENTS
-Illustrated in ~ig. 1 is a marine propulsion device, such as an outboard motor 10, including a power S head 12 which houses an internal combustion engine 14 and a lower unit 16 having a gear box 18. Rotatably mounted in the gear box 18 is a propeller shaft 20 carrying a pro-peller 22 on the outer end. Located within the gear box 18 is a pair of facing, axially-spaced gears 24 and 26 which are carried by and are drivingly connected to the ~ropeller shaft 20. Extending through the lower unit 16 is a rotatably mounted drive shaft 28 carrying a lower bevel gear 30 which meshes with ~he gears 24 and 26. The drive shaft 28 is drivingly connected to the engine 14 through a two-speed transmission, designated generally by the reference numeral 32.
The transmission 32 includes an input shaft 34 which is rotatably mounted such as by a bearing 35 and is drivingly connected to the engine 14, a first drive gear 36 carried by and mounted for common rotation with the input shaft 34, and a second drive gear 38 mounted for rotation coaxially with and independently of the input shaft 34.
The transmission 32 also includes a first driven gear 40 which meshes with the first drive gear 3~ and is mounted for rotation coaxially with the drive shaft 28 and a second driven gear 42 which meshes with the second drive gPar 38 and is mounted for common rotation with the drive shaft 28.
For reasons explained below, the gear ratio of the second drive gear 38 to the second driven gear 42 is greater than the gear ratio of the first drive gear 36 to the first driven gear 40.
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The first driven gear 40 is drivingly connec~ed to the drive shaft 28 by a suitable one-way, overrunning clutch means 44 disposed therebetween. The one-way clutch means 44 is constructed in the conventional manner so a detailed description of its structural features and mode of operation is not necessary for full understanding of the invention. Generally, the one-way clutch means 44 is arranged so that, in response to rotation o the first driven gear 40 via the first drive gear 36 and the input -shaft 34, it drives the drive shaft 28 in one rotary direc-tion. Further, the one-way clutch means 44 is arranged so that, when the rotational speed of the drive shaft 28 in the one rotary direction exceeds the rotational speed of the first drive gear 40 in the same rotary direction (i.e., when the drive shaft 28 overruns the first driven gear 40), the drive shaft 28 becomes free wheeling relative to the first driven gear 40.
For example, the one-way clutch means 44 can include teeth or lugs (not shown) which are drivingly connected to the first driven gear 40, which are biased into driving engagement with complementary teeth or lugs (not shown~ provided on the drive shaft 28, and which are disengaged from the drive shaft teeth or lugs when over-running occurs.
Carried on the input shaft 34 is a centrifugal clutch which is operable, in response to rotation of the in-put shaft 34 above a predetermined speed, to drivingly connect the second drive gear 38 to the input sha~t 34.
While various arrangements can be used, in the specific construction illustrated, there is provided a centrifugal clutch 46 including a clutch drum ~8 which has a cylindrical inner surface 50 and is mounted for common . .
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rotation with the input sha~t 34. The clutch 46 also has two or more clutch shoes 52 carried by a clutch shoe driver 54 which is drivingly connected ~o the second drive gear 38 and is mounted for rotation coaxially with and independently of the input shaft 34. The clutch shoe driver 54 rotates the clutch shoes 52, in response to rotation o~ the second drive gear 38, and is arranged in a suitable manner to cause the clutch shoes 52 to move radially between an inner or retracted position spaced from the clutch drum 48 and an outer or extended position in driving engagement with the clutch drum inner surface 50 when the second drive gear 38 is rotated a~ a speed corresponding to the predetermined input shaft speed.
The clutch shoes 52 can be constructed in any suitable manner including an arcuate surface adapted to drivingly engage the inner surface 50 of the clutch drum 48 when the clutch shoe driver 54 is rotated at a speed cor-responding to the predetermined input shaft speed. Outward movement of the clutch shoes 52 from the retracted positlon, in absence of rotation of the clutch shoe driver above the predetermined speed, is restrained by a suitable means (not shown). ~:
In operation, when the input shaft 34 is being rotated at low or moderate speeds, the drive sha~t 28, and thus the propeller 22, is driven by the input shaft 34 via the first drive gear 36, the first driven gear 40, and the ;:
one-way clutch means 44. The second drive gear 38 is also being driven by the second driven gear 40 at this time but is free wheeling relative to the input sha~t 34 because the :
clutch shoe driver 54 is being rotated at a speed less than the predetermined speed at which the clutch shoes 52 are moved radially outwardly to the extended position.
l~en the engine speed is increased to a point where the clutch shoe driver 54 is rotated above the predetermined speed, the clutch shoes 52 drivingly engage the inner surface 50 of the clutch drum 48 to drivingly connect the second drive gear 38 to the input shaft 34. -The second drive gear 38 thereafter drives the second driven gear 42.
Since the gear ratio between the second drive gear 38 and the second driven gear 42 is greater than the gear ratio between the first drive gear 36 and the first driven gear 40, the drive shaft 28 is rotated at a rate faster than the rate of rotation of the first driven gear 40, causing the one-way clutch means 44 to disengage so that the drive shaft 28 is free wheeling reIative to the first driven gear 40. The drive shaft 28 thereafter is driven by the input shaft 34 via the centrifugal clutch 46, the second drive gear 38 and the second driven gear 42.
When the engine speed is decreased to a point where the rate of rotation of the clutch shoe driver 54 falls below the predetermined speed, the clutch shoes 52 return toward the retracted position (i.e., disengage ~rom the clutch drum 48), thereby disconnecting the second drive gear 38 from the input shaft 34 and causing a reduction in the rate of rotation of the drive shaft 28 to a speed where the one-way clutch means 44 re-engages. The drive shaft 28 thereafter is driven by the input shaft 34 via the first drive gear 36, the first driven gear 40, and the one-way clutch means 44.
With this arrangement, a relative large propeller can be used to develop sufficient thrust to get the boat to "go over the hump" on the thrust vs. speed curve with large boat loads or while towing skiers and yet the engine will - - . . . .. . . ~ . . :
~ \
not overspeed at ~ull throttle and maximum boat speed after the boat is planing. That is, the engine 14 can be operated at a high speed while rotating the propeller 22 at a low speed via the input shaft 34, the first drive gear 36, the first driven gear 40, and the one-way clutch means 44, to develop su~ficient power or thrust to get the boat "over the hump." Once the boat is planing and less engine power is required to rotate the propeller 22 at maximum speed, the transmission 32 shi~ts, via the centrifugal clutch 46, to the higher gear ratio provided by the second drive gear 38 and the second driven gear 42, thereby preventing the engine 14 from overspeeding at full throttle and maximum boat speed. Thus, smaller, more economical engines can be used for carrying heavy loads or towing water skiers, which tasks normally require larger engines to get the boat "over the hump" and into planing trim.
Further, the two-speed transmission 32 can be advantageously used in propulsion units for racing boats. ~
The transmission permits the engine to rapidly turn up to ~;
higher r.p.m.'s while accelerating out of a turn and then shifts, after the boat is planing, to facilitate top speed operation. When a centrifugal clutch is employed as in the embodiment illustrated in Fig. 1, this shifting is accomplished automatically without any effort on the part of the driver and higher lap speeds normally can be obtained for a given engine.
Fig. 2 illustrates another embodiment of the invention including various components which are constructed and arranged in a manner similar to the embodiment illus- - -trated in Fig. 1. Thus, the same reference numerals have been assigned to common components. -;- . . .. . , ., . . . . ~. . , . . - : . ,.
The basic difference between the marine pro-pulsion unit 60 shown in Fig. 2 and the marine propulsion unit 10 shown in Fig. 1 is that the former employs dual drive shafts instead of a single drive shaft. The use of dual drive shafts affords the use of smaller drive gears to impart the same power to the propeller and ~hus less frontal area for the gear case 18 and/or smaller size of the portion of the housing enclosing the upper end of the drive shafts.
Located within the gear box 18 and dri~ingly connected to the propeller sha~t 20 are a pair of bevel gears 62 which can be a unitary element as illustrated or separate gears. Extending through the lower unit 16 is a first rotatably mounted drive shaft 64 which is similar to the drive shaft 28 in Fig. 1 and carries a lower bevel gear 66 which meshes with one of the gears 62. Extending through the lower unit 16 in parallel relationship to the first drive shaft 64 in a second rotatably mounted drive shaft 68 carrying a lower bevel gear 70 which meshes with the other of the gears 62. The first and second drive shafts 64 and 68 are drivingly connected to the engine by a two-speed transmission 32a which is constructed and operates in the same basic manner as the transmission 32 in Fig. 1, except that the second driven gear 42a, in addi-tion to meshing with the second drive gear 38, also meshes with a third driven gear 72 mounted on the upper end of the second drive shaft 68 for common rotation therewith.
In operation, when the input shaft 34 is being rotated at low or moderate speeds, the first drive shaft 64 is driven by the input shaft 34 via the first drive gear 36, the first driven gear 40, and the one-way clutch means 44.
The second drive shaft 68 is driven by the input shaft 34 via the first drive gear 36, the first driven gear 40, the one-way clutch means 44, the second driven gear 42a and the third driven gear 72 to effect counter rotation of the drive shafts 64 and 68 and the gears 66 and 70. The second drive gear 38 is also being driven by the second driven gear 42a at the same time but is free wheeling relative to the input shaft 34 because the clutch shoe driver 54 is being rotated at a speed less than the speed at which the clutch shoes 52 are moved radially outwardly to an extended position.
When the engine speed is increased to a point where the clutch shoe driver 54 is rotated above the pre-determined speed, the clutch shoes 52 engage the clutch drum 48 to drivingly connect the second drive gear 38 to the input shaft 34, causing the transmission 32a to shift ~ .
as described above. The drive shafts 64 and 68 thereafter are driven by the input shaft 34 via the centrifugal clutch .
46, the second drive gear 38 and the respec~ive second :
driven gear 42a and third driven gear 72. When the engine speed is decreased, the transmission shifts back to the lower gear ratio as described above. :~
While a centrifugal clutch has been illustrated and described, and generally is preferred because automatic shifting is afforded, it is within the scope of the invention to employ a suitable manually shiftable clutch for selectively . :~.
connecting the second driven gear 38 to the input shaft 34.
Although the two-speed transmission of ~he invention has been described for use on an outboard motor, it should be understood that it can be used in other marine propulsion ~
devices, such as stern drive units, and in other similar .
applications. .
Further, while the transmission has been illustrated and described as being located in the powerhead, immediately -11- .
below the engine and above the drive shaft and on ~he top of the drive shaft housing, it can be located in the lower unit above the gear box, such as in the lower end portion of the drive shaft housing connected to the gear box.
Various of the features of the inventlon are set forth in the following claims:
Claims (36)
1. A marine propulsion device comprising an input shaft drivingly connected to a power source, a lower unit having a rotatably mounted drive shaft, a propeller shaft rotatably mounted in said lower unit and carrying a pro-peller, means drivingly connecting said drive shaft to said propeller shaft, and a two-speed transmission drivingly connecting said input shaft to said drive shaft and including a first drive gear mounted for common rotation with said input shaft, a second drive gear mounted for rotation coaxially with and independently of said input shaft, a first driven gear mounted for rotation coaxially with said drive shaft and disposed in enmeshing engagement with said first drive gear, the gear ratio of said first drive gear to said first driven gear having a first value, a second driven gear mounted for common rotation with said drive shaft and disposed in enmeshing engagement with said second drive gear, the gear ratio of said second drive gear to said second driven gear having a second value greater than said first value, first clutch means operable for drivingly connecting said first drive gear to said drive shaft to afford rotation of said drive shaft in one rotary direction through said first drive and driven gears and to permit rotation of said drive shaft relative to said first driven gear when said drive shaft is rotated in said one rotary direction at a rate of rotation greater than the rate of rotation of said first driven gear, and second clutch means for selectively drivingly connecting said second drive gear to said input shaft whereby said drive shaft thereafter is rotated in said one rotary direction, in response to rotation of said input shaft, through said second drive and driven gears and independently of said first drive and driven gears.
2. A marine propulsion device according to Claim 1 wherein said second clutch means is operable, in response to rotation of said input shaft, to drivingly connect said second driven gear to said input shaft when said input shaft is rotated above a predetermined speed.
3. A marine propulsion device according to Claim 2 wherein said second clutch means comprises a centrifugal clutch carried by said input shaft and including means operable, in response to rotation of said second drive gear by said second driven gear, for drivingly connecting said second drive gear to said input shaft when the rotational speed of said second driven gear exceeds a speed corres-ponding to said predetermined speed.
4. A marine propulsion device according to Claim 3 wherein said centrifugal clutch includes a clutch drum mounted for common rotation with said input shaft, a plurality of clutch shoes, and a clutch shoe driver mounted for common rotation with said second drive gear and for rotation indepen-dently of said input shaft, said clutch shoe driver carrying said clutch shoes and operable, in response to rotation of said second drive gear, for rotatably driving said clutch shoes so as to cause radially outward movement of said clutch shoes from a retracted position spaced from said clutch drum to an extended position in driving engagement with such clutch drum.
5. A marine propulsion device comprising an input shaft drivingly connected to a power source, a lower unit including a rotatably mounted propeller shaft carrying a propeller, first and second drive shafts rotatably mounted in said lower unit and drivingly connected to said propeller shaft, and a two-speed transmission drivingly connecting said input shaft to said first and second drive shafts and including a first drive gear mounted for common rotation with said input shaft, a second drive gear mounted for rotation coaxially with and independently of said input shaft, a first driven gear mounted for rotation coaxially with said first drive shaft and disposed in enmeshing engagement with said first driven gear, the gear ratio of said first drive gear to said first driven gear having a first value, a second driven gear mounted for common rota-tion with said first drive shaft and disposed in enmeshing engagement with said second drive gear, the gear ratio of said second drive gear to said second driven gear having a second value greater than said first value, a third driven gear mounted for rotation common with said second drive shaft and disposed in enmeshing engagement with said second driven gear, first clutch means operable for drivingly connecting said first driven gear to said first drive shaft to afford rotation of said first drive shaft in one rotary direction through said first drive and driven gears, to afford rotation of said second drive shaft in a rotary direction opposite to said one direction through said first drive and driven gears, said second driven gear, and said third driven gear, and to permit rotation of said first drive shaft relative to said first driven gear when said first drive shaft is rotated in said one rotary direction at a rate of rotation greater than the rate of rotation of said first driven gear, and second clutch means for selectively drivingly connecting said second drive gear to said input shaft whereby said first drive shaft thereafter is rotated in said one rotary direction, in response to rotation of said input shaft, through said second drive and driven gears and independently of said first drive and driven gears and whereby said second drive shaft thereafter is rotated in a rotary direction opposite to said one rotary direction, in response to rotation of said input shaft, through said second drive gear, said second driven gear and said third driven gear.
6. A marine propulsion device according to Claim 5 wherein said second clutch means is operable, in response to rotation of said input shaft, to drivingly connect said second driven gear to said input shaft when said input shaft is rotated above a predetermined speed.
7. A marine propulsion device according to Claim 6 wherein said second clutch means comprises a centrifugal clutch carried by said input shaft and including means operable, in response to rotation of said second drive gear by said second driven gear, for drivingly connecting said second drive gear to said input shaft when the rotational speed of said second driven gear exceeds a speed corres-ponding to said predetermined speed.
8. A marine propulsion device according to Claim 7 wherein said centrifugal clutch includes a clutch drum mounted for common rotation with said input shaft, a plurality of clutch shoes, and a clutch shoe driver mounted for common rotation with said second drive gear and for rotation independently of said input shaft, said clutch shoe driver carrying said clutch shoes and operable, in response to rotation of said second driver gear, for rotatably driving said clutch shoes so as to cause radially outward movement of said clutch shoes from a retracted posi-tion spaced from said clutch drum to an extended position in driving engagement with such clutch drum.
9. A two-speed transmission including an input shaft adapted for connection to a power source, a drive shaft, a first drive gear mounted for common rotation with said input shaft, a second drive gear mounted for rotation coaxially with and independently of said input shaft, a first driven gear mounted for rotation coaxially with said drive shaft and disposed in enmeshing engagement with said first drive gear, the gear ratio of said first drive gear to said first driven gear having a first value, a second driven gear mounted for common rotation with said drive shaft and disposed in enmeshing engagement with said second drive gear, the gear ratio of said second drive gear to second driven gear having a second value greater than said first value, first clutch means operable for drivingly connecting said first driven gear to said drive shaft to afford rotation of said drive shaft in one rotary direction through said first drive and driven gears and to permit rotation of said drive shaft relative to said first driven gear when said drive shaft is rotated in said one rotary direction at a rate of rotation greater than the rate of rotation of said first driven gear, and second clutch means for selectively drivingly connecting said second drive gear to said input shaft whereby said drive shaft there-after is rotated in said one rotary direction, in response to rotation of said input shaft, through said second drive and driven gears and independently of said first drive and driven gears.
10. A two-speed transmission according to Claim 9 wherein said second clutch means is operable, in response to rotation of said input shaft, to drivingly connect said second driven gear to said input shaft when said input shaft is rotated above a predetermined speed.
11. A two-speed transmission according to Claim 10 wherein said second clutch means comprises a centrifugal clutch carried by said input shaft and including means operable, in response to rotation of said second drive gear by said second driven gear, for drivingly connecting said second drive gear to said input shaft when the rotational speed of said second driven gear exceeds a speed corresponding to said predetermined speed.
12. A two-speed transmission according to Claim 11 wherein said centrifugal clutch includes a clutch drum mounted for common rotation with said input shaft, a plurality of clutch shoes, and a clutch shoe driver mounted for common rotation with said second drive gear and for rotation independently of said input shaft, said clutch shoe driver carrying said clutch shoes and operable, in response to rotation of said second drive gear, for rotatably driving said clutch shoes so as to cause radially outward movement of said clutch shoes from a retracted position spaced from said clutch drum to an extended position in driving engagement with such clutch drum.
13. A marine propulsion device comprising an input shaft drivingly connected to a power source, a lower unit having a rotatably mounted drive shaft, a propeller shaft rotatably mounted in said lower unit and carrying a pro-peller, means drivingly connecting said drive shaft to said propeller shaft, and a two-speed transmission drivingly connecting said input shaft to said drive shaft and including a first drive gear mounted for common rotation with said input shaft, a second drive gear mounted for rotation.
coaxially with and independently of said input shaft, a first driven gear mounted for rotation coaxially with said drive shaft and disposed in enmeshing engagement with said first drive gear, the gear ratio of said first drive gear to said first driven gear having a first value, a second driven gear mounted for common rotation with said drive shaft and disposed in enmeshing engagement with said second drive gear, the gear ratio of said second drive gear to said second driven gear having a second value greater than said first value, first clutch means operable for drivingly connecting said first driven gear to said drive shaft to afford rotation of said drive shaft in one rotary direction through said first drive and driven gears and to permit rotation of said drive shaft relative to said first driven gear when said drive shaft is rotated in said one rotary direction at a rate of rotation greater than the rate of rotation of said first driven gear, and second clutch means for selectively drivingly connecting said second drive gear to said input shaft,whereby said drive shaft thereafter is rotated in said one rotary direction, in response to rotation of said input shaft, through said second drive and driven gears and independently of said first drive and driven gears.
coaxially with and independently of said input shaft, a first driven gear mounted for rotation coaxially with said drive shaft and disposed in enmeshing engagement with said first drive gear, the gear ratio of said first drive gear to said first driven gear having a first value, a second driven gear mounted for common rotation with said drive shaft and disposed in enmeshing engagement with said second drive gear, the gear ratio of said second drive gear to said second driven gear having a second value greater than said first value, first clutch means operable for drivingly connecting said first driven gear to said drive shaft to afford rotation of said drive shaft in one rotary direction through said first drive and driven gears and to permit rotation of said drive shaft relative to said first driven gear when said drive shaft is rotated in said one rotary direction at a rate of rotation greater than the rate of rotation of said first driven gear, and second clutch means for selectively drivingly connecting said second drive gear to said input shaft,whereby said drive shaft thereafter is rotated in said one rotary direction, in response to rotation of said input shaft, through said second drive and driven gears and independently of said first drive and driven gears.
14. A marine propulsion device according to Claim 13 wherein said second clutch means is operable, in response to rotation of said input shaft, to drivingly connect said second driven gear to said input shaft when said input shaft is rotated above a predetermined speed.
15. A marine propulsion device according to Claim 14 wherein said second clutch means comprises a centrifugal clutch carried by said input shaft and including means operable, in response to rotation of said second drive gear by said second driven gear, for drivingly connectin said second drive gear to said input shaft when the rotational speed of said second driven gear exceeds a speed corres-ponding to said predetermined speed.
16. A marine propulsion device according to Claim 15 wherein said centrifugal clutch includes a clutch drum mounted for common rotation with said input shaft, a plurality of clutch shoes, and a clutch shoe driver mounted for common rotationwwith said second drive gear and for rotation indepen-dently of said input shaft, said clutch shoe driver carrying said clutch shoes and operable, in response to rotation of said second drive gear, for rotatably driving said clutch shoes so as to cause radially outward movement of said clutch shoes from a retracted position spaced from said clutch drum to an extended position in driving engagement with said clutch drum.
17. A marine propulsion device comprising an input shaft drivingly connected to a power source, a lower unit including a rotatably mounted propeller shaft carrying a propeller, first and second drive shafts rotatably mounted in said lower unit and drivingly connected to said propeller shaft, and a two-speed transmission drivingly connecting said input shaft to said first and second drive shafts and including a first drive gear mounted for common rotation with said input shaft, a second drive gear mounted for rotation coaxially with and independently of said input shaft, a first driven gear mounted for rotation coaxially with said first drive shaft and disposed in enmeshing engagement with said first driven gear, the gear ratio of said first drive gear to said first driven gear having a first value, a second driven gear mounted for common rota-tion with said first drive shaft and disposed in enmeshing engagement with said second drive gear, the gear ratio of said second drive gear to said second driven gear having a second value greater than said first value, a third driven gear mounted for rotation common with said second drive shaft and disposed in enmeshing engagement with said second driven gear, first clutch means operable for drivingly connecting said first driven gear to said first drive shaft to afford rotation of said first drive shaft in one rotary direction through said first drive and driven gears, to afford rotation of said second drive shaft in a rotary direction opposite to said one direction through said first drive and driven gears, said second driven gear, and said third driven gear, and to permit rotation of said first drive shaft relative to said first driven gear when said first drive shaft is rotated in said one rotary direction at a rate of rotation greater than the rate of rotation of said
17. A marine propulsion device comprising an input shaft drivingly connected to a power source, a lower unit including a rotatably mounted propeller shaft carrying a propeller, first and second drive shafts rotatably mounted in said lower unit and drivingly connected to said propeller shaft, and a two-speed transmission drivingly connecting said input shaft to said first and second drive shafts and including a first drive gear mounted for common rotation with said input shaft, a second drive gear mounted for rotation coaxially with and independently of said input shaft, a first driven gear mounted for rotation coaxially with said first drive shaft and disposed in enmeshing engagement with said first driven gear, the gear ratio of said first drive gear to said first driven gear having a first value, a second driven gear mounted for common rota-tion with said first drive shaft and disposed in enmeshing engagement with said second drive gear, the gear ratio of said second drive gear to said second driven gear having a second value greater than said first value, a third driven gear mounted for rotation common with said second drive shaft and disposed in enmeshing engagement with said second driven gear, first clutch means operable for drivingly connecting said first driven gear to said first drive shaft to afford rotation of said first drive shaft in one rotary direction through said first drive and driven gears, to afford rotation of said second drive shaft in a rotary direction opposite to said one direction through said first drive and driven gears, said second driven gear, and said third driven gear, and to permit rotation of said first drive shaft relative to said first driven gear when said first drive shaft is rotated in said one rotary direction at a rate of rotation greater than the rate of rotation of said
Claim 17 continued first driven gear, and second clutch means for selectively drivingly connecting said second drive gear to said input shaft whereby said first drive shaft thereafter is rotated in said one rotary direction, in response to rotation of said input shaft, through said second drive and driven gears and independently of said first drive and driven gears and whereby said second drive shaft thereafter is rotated in a rotary direction opposite to said one rotary direction, in response to rotation of said input shaft, through said second drive gear, said second driven gear and said third driven gear.
18. A marine propulsion device according to Claim 17 wherein said second clutch means is operable, in response to rotation of said input shaft, to drivingly connect said second driven gear to said input shaft when said input shaft is rotated above a predetermined speed.
19. A marine propulsion device according to Claim 18 wherein said second clutch means comprises a centrifugal clutch carried by said input shaft and including means operable, in response to rotation of said second drive gear by said second driven gear, for drivingly connecting said second drive gear to said input shaft when the rotational speed of said second driven gear exceeds a speed corres-ponding to said predetermined speed.
20. A marine propulsion device according to Claim 19 wherein said centrifugal clutch includes a clutch drum mounted for common rotation with said input shaft, a plurality of clutch shoes, and a clutch shoe driver mounted for common rotation with said second drive gear and for rotation independently of said input shaft, said clutch shoe driver carrying said clutch shoes and operable, in response to rotation of said second driven gear, for rotatably driving said clutch shoes so as to cause radially outward movement of said clutch shoes from a retracted position spaced from said clutch drum to an extended position in driving engagement with said clutch drum.
21. A two-speed transmission including an input shaft adapted for connection to a power source, a drive shaft, a first drive gear mounted for common rotation with said input shaft, a second drive gear mounted for rotation coaxially with and independently of said input shaft, a first driven gear mounted for rotation coaxially with said drive shaft and disposed in enmeshing engagement with said first drive gear, the gear ratio of said first drive gear to said first driven gear having a first value, a second driven gear mounted for common rotation with said drive shaft and disposed in enmeshing engagement with said second drive gear, the gear ratio of said second drive gear to second driven gear having a second value greater than said first value, first clutch means operable for drivingly connecting said first driven gear to said drive shaft to afford rotation of said drive shaft in one rotary direction through said first drive and driven gears and to permit rotation of said drive shaft relative to said first driven gear when said drive shaft is rotated in said one rotary direction at a rate of rotation greater than the rate of rotation of said first driven gear, and second clutch means for selectively drivingly connecting said second drive gear to said input shaft whereby said drive shaft there-after is rotated in said one rotary direction, in response to rotation of said input shaft, through said second drive and driven gears and independently of said first drive and driven gears.
22. A two-speed transmission according to Claim 21 wherein said second clutch means is operable, in response to rotation of said input shaft, to drivingly connect said second driven gear to said input shaft when said input shaft is rotated above a predetermined speed.
23. A two-speed transmission according to Claim 22 wherein said second clutch means comprises a centrifugal clutch carried by said input shaft and including means operable, in response to rotation of said second drive gear by said second driven gear, for drivingly connecting said second drive gear to said input shaft when the rotational speed of said second driven gear exceeds a speed corresponding to said predetermined speed.
24. A two-speed transmission according to Claim 23 wherein said centrifugal clutch includes a clutch drum mounted for common rotation with said input shaft, a plurality of clutch shoes, and a clutch shoe driver mounted for common rotation with said second drive gear and for rotation independently of said input shaft, said clutch shoe driver carrying said clutch shoes and operable, in response to rotation of said second drive gear, for rotatably driving said clutch shoes so as to cause radially outward movement of said clutch shoes from a retracted position spaced from said clutch drum to an extended position in driving engagement with said clutch drum.
25. A marine propulsion device comprising an input shaft drivingly connected to a power source, a lower unit having a rotatably mounted drive shaft, a propeller shaft rotatably mounted in said lower unit and carrying a propeller, means drivingly connecting said drive shaft to said propeller shaft, and a two-speed transmission drivingly connecting said input shaft to said drive shaft and including a first drive gear fixed to said input shaft for common rotation with said input shaft, a second drive gear mounted for rotation coaxially with and independently of said input shaft, a first driven gear mounted for rotation coaxially with and independently of said drive shaft and disposed in enmeshing engagement with said first drive gear; the gear ratio of said first drive gear to said first driven gear having a first value, a second driven gear fixed to said drive shaft for common rotation with said drive shaft and disposed in enmeshing engagement with said second drive gear, the gear ratio of said second drive gear to said second driven gear having a second value greater than said first value, first clutch means operable for drivingly connecting said first driven gear to said drive shaft to afford rotation of said drive shaft in one rotary direction through said first drive and driven gears and to permit rotation of said drive shaft relative to said first driven gear when said drive shaft is rotated in said one rotary direction at a rate of rotation greater than the rate of rotation of said first driven gear, and second clutch means for selectively drivingly connecting said second drive gear to said input shaft when said input
25. A marine propulsion device comprising an input shaft drivingly connected to a power source, a lower unit having a rotatably mounted drive shaft, a propeller shaft rotatably mounted in said lower unit and carrying a propeller, means drivingly connecting said drive shaft to said propeller shaft, and a two-speed transmission drivingly connecting said input shaft to said drive shaft and including a first drive gear fixed to said input shaft for common rotation with said input shaft, a second drive gear mounted for rotation coaxially with and independently of said input shaft, a first driven gear mounted for rotation coaxially with and independently of said drive shaft and disposed in enmeshing engagement with said first drive gear; the gear ratio of said first drive gear to said first driven gear having a first value, a second driven gear fixed to said drive shaft for common rotation with said drive shaft and disposed in enmeshing engagement with said second drive gear, the gear ratio of said second drive gear to said second driven gear having a second value greater than said first value, first clutch means operable for drivingly connecting said first driven gear to said drive shaft to afford rotation of said drive shaft in one rotary direction through said first drive and driven gears and to permit rotation of said drive shaft relative to said first driven gear when said drive shaft is rotated in said one rotary direction at a rate of rotation greater than the rate of rotation of said first driven gear, and second clutch means for selectively drivingly connecting said second drive gear to said input shaft when said input
Claim 25 continued shaft is rotated above a predetermined speed, said second clutch means comprising a centrifugal clutch in-cluding a clutch drum mounted for common rotation with said input shaft, a plurality of clutch shoes, and a clutch shoe driver mounted for common rotation with said second drive gear and for rotation independently of said input shaft, said clutch shoe driver carrying said clutch shoes and being operable, in response to rotation of said second drive gear, for rotatably driving said clutch shoes so as to cause radially outward movement of said clutch shoes from a retracted position spaced from said clutch drum to an extended position in driving engagement with said clutch drum.
26. A marine propulsion device comprising an input shaft drivingly connected to a power source, a lower unit including a rotatably mounted propeller shaft carrying a propeller, first and second drive shafts rotatably mounted in said lower unit and drivingly connected to said propeller shaft, and a two-speed transmission drivingly connecting said input shaft to said first and second drive shafts and including a first drive gear fixed to said input shaft for common rotation with said input shaft, a second drive gear mounted for rotation coaxially with and independently of said input shaft, a first driven gear mounted for rotation coaxially with and independently of said first drive shaft and disposed in enmeshing engage-ment with said first driven gear, the gear ratio of said first drive gear to said first driven gear having a first value, a second driven gear fixed on said first drive shaft for common rotation with said first drive shaft and disposed in enmeshing engagement with said second drive gear, the gear ratio of said second drive gear to said second driven gear having a second value greater than said first value, a third driven gear fixed for rotation in common with said second drive shaft and disposed in enmeshing engagement with said second driven gear, first clutch means operable for drivingly connecting said first driven gear to said first drive shaft to afford rotation of said first drive shaft in one rotary direction through said first drive and driven gears, and to permit rotation of said first drive shaft relative to said first driven gear when said first drive shaft is rotated in said one rotary direction at a rate of rotation greater than the rate of rotation of
26. A marine propulsion device comprising an input shaft drivingly connected to a power source, a lower unit including a rotatably mounted propeller shaft carrying a propeller, first and second drive shafts rotatably mounted in said lower unit and drivingly connected to said propeller shaft, and a two-speed transmission drivingly connecting said input shaft to said first and second drive shafts and including a first drive gear fixed to said input shaft for common rotation with said input shaft, a second drive gear mounted for rotation coaxially with and independently of said input shaft, a first driven gear mounted for rotation coaxially with and independently of said first drive shaft and disposed in enmeshing engage-ment with said first driven gear, the gear ratio of said first drive gear to said first driven gear having a first value, a second driven gear fixed on said first drive shaft for common rotation with said first drive shaft and disposed in enmeshing engagement with said second drive gear, the gear ratio of said second drive gear to said second driven gear having a second value greater than said first value, a third driven gear fixed for rotation in common with said second drive shaft and disposed in enmeshing engagement with said second driven gear, first clutch means operable for drivingly connecting said first driven gear to said first drive shaft to afford rotation of said first drive shaft in one rotary direction through said first drive and driven gears, and to permit rotation of said first drive shaft relative to said first driven gear when said first drive shaft is rotated in said one rotary direction at a rate of rotation greater than the rate of rotation of
Claim 26 continued said first driven gear, and second clutch means for selectively drivingly connecting said second drive gear to said input shaft when said input shaft is rotated above a predetermined speed, said second clutch means comprising a centrifugal clutch including a clutch drum mounted for common rotation with said input shaft, a plurality of clutch shoes, and a clutch shoe driver mounted for common rotation with said second drive gear and for rotation in-dependently of said input shaft, said clutch shoe driver carrying said clutch shoes and being operable, in response to rotation of said second drive gear, for rotatably driving said clutch shoes so as to cause radially outward movement of said clutch shoes from a retracted position spaced from said clutch drum to an extended position in driving engagement with said clutch drum.
27. A two-speed transmission including an input shaft adapted for connection to a power source a drive shaft, a first drive gear fixed to said input shaft for common rotation with said input shaft, a second drive gear mounted for rotation coaxially with and independently of said input shaft, a first driven gear mounted for rotation coaxially with and independently of said drive shaft and disposed in enmeshing engagement with said first drive gear, the gear ratio of said first drive gear to said first driven gear having a first value, a second driven gear fixed to said drive shaft for common rotation with said drive shaft and disposed in enmeshing engagement with said second drive gear, the gear ratio of said second drive gear to second driven gear having a second value greater than said first value, first clutch means operable for drivingly connecting said first driven gear to said drive shaft to afford rotation of said drive shaft in one rotary direction through said first drive and driven gears and to permit rotation of said drive shaft relative to said first driven gear when said drive shaft is rotated in said one rotary direction at a rate of rotation greater than the rate of rotation of said first driven gear, and second clutch means for selectively drivingly connecting said second drive gear to said input shaft when said input shaft is rotated above a predetermined speed, said second clutch means comprising a centrifugal clutch including a clutch drum mounted for common rotation with said input shaft, a plurality of clutch shoes, and a clutch shoe driver mounted for common rotation with said second drive gear and for rotation independently of said input shaft,
27. A two-speed transmission including an input shaft adapted for connection to a power source a drive shaft, a first drive gear fixed to said input shaft for common rotation with said input shaft, a second drive gear mounted for rotation coaxially with and independently of said input shaft, a first driven gear mounted for rotation coaxially with and independently of said drive shaft and disposed in enmeshing engagement with said first drive gear, the gear ratio of said first drive gear to said first driven gear having a first value, a second driven gear fixed to said drive shaft for common rotation with said drive shaft and disposed in enmeshing engagement with said second drive gear, the gear ratio of said second drive gear to second driven gear having a second value greater than said first value, first clutch means operable for drivingly connecting said first driven gear to said drive shaft to afford rotation of said drive shaft in one rotary direction through said first drive and driven gears and to permit rotation of said drive shaft relative to said first driven gear when said drive shaft is rotated in said one rotary direction at a rate of rotation greater than the rate of rotation of said first driven gear, and second clutch means for selectively drivingly connecting said second drive gear to said input shaft when said input shaft is rotated above a predetermined speed, said second clutch means comprising a centrifugal clutch including a clutch drum mounted for common rotation with said input shaft, a plurality of clutch shoes, and a clutch shoe driver mounted for common rotation with said second drive gear and for rotation independently of said input shaft,
Claim 27 continued said clutch shoe driver carrying said clutch shoes and being operable, in response to rotation of said second drive gear, for rotatably driving said clutch shoes so as to cause radially outward movement of said clutch shoes from a retracted position spaced from said clutch drum to an extended position in driving engagement with said clutch drum.
28. A marine propulsion device comprising an input shaft drivingly connected to a power source, a lower unit having a rotatably mounted drive shaft, a propeller shaft rotatably mounted in said lower unit and carrying a propeller, means drivingly connecting said drive shaft to said propeller shaft, and a two-speed transmission drivingly connecting said input shaft to said drive shaft and including first drive means for selectively drivingly connecting said input shaft and said drive shaft and including a drive gear, a driven gear in meshing engagement with said drive gear, and a one-way overrunning clutch drivingly connecting said input shaft and said drive shaft through said drive and driven gears when the rotational speed of said input shaft is less than a predetermined value, said first drive means having an input-output speed ratio with a first value, and second drive means for selectively drivingly connecting said input shaft and said drive shaft when the rotational speed of said input shaft is greater than said predetermined value, said second drive means including a selectively actuatable clutch for drivingly connecting said input shaft and said drive shaft, said second drive means having an input-output speed ratio with a second value greater than said first value.
29. A marine propulsion device in accordance with Claim 28 wherein said input shaft and said drive shaft are axially offset.
30. A marine propulsion device in accordance with Claim 28 wherein said second drive means includes a second drive gear and a second driven gear in meshing engagement with said second drive gear.
31. A marine propulsion device in accordance with Claim 28 wherein said second drive means clutch comprises a centrifugal clutch including a drum drivingly connected to one of said input shaft and said drive shaft and a driver drivingly connected to the other of said input shaft and said drive shaft and operable in response to driver rotation above a predetermined speed to effect driving engagement between said driver and said drum and therefore between said input shaft and said drive shaft.
32. A marine propulsion device in accordance with Claim 28 and further including a second drive shaft rotatably mounted in said lower unit and drivingly connected to said propeller shaft, and means adjacent said first and second drive means for drivingly connecting said first mentioned drive shaft to said second drive shaft for transmissions of power to said propeller shaft through said first mentioned and second drive shaft.
33. A marine propulsion device comprising an input shaft drivingly connected to a power source, a lower unit having a rotatably mounted drive shaft offset from said input shaft, a propeller shaft rotatably mounted in said lower unit and carrying a propeller, means drivingly connecting said drive shaft to said propeller shaft, and a two-speed transmission drivingly connecting said input shaft to said drive shaft and including first drive and driven gears in meshing engagement, the gear ratio of said first drive gear to said first driven gear having a first value, second drive and driven gears in meshing en-gagement, the gear ratio of said second drive gear to said second driven gear having a second value greater than said first value, means fixedly connecting one of said first drive gear to said input shaft and said first driven gear to said drive shaft; a one-way overrunning clutch connecting the other of said first drive gear to said input shaft and said first driven gear to said drive shaft, means fixedly connecting one of said second drive gear to said input shaft and said second driven gear to said drive shaft and a centrifugal clutch for selectively drivingly connecting the other of said input shaft to said second drive gear and said second driven gear to said drive shaft, said centrifugal clutch including a drum fixed to one of said gear and said shaft included in the other of said input shaft which is connectable to said second drive gear and said second driven gear which is connectable to said drive shaft, a driver fixed to the other of said gear and said
33. A marine propulsion device comprising an input shaft drivingly connected to a power source, a lower unit having a rotatably mounted drive shaft offset from said input shaft, a propeller shaft rotatably mounted in said lower unit and carrying a propeller, means drivingly connecting said drive shaft to said propeller shaft, and a two-speed transmission drivingly connecting said input shaft to said drive shaft and including first drive and driven gears in meshing engagement, the gear ratio of said first drive gear to said first driven gear having a first value, second drive and driven gears in meshing en-gagement, the gear ratio of said second drive gear to said second driven gear having a second value greater than said first value, means fixedly connecting one of said first drive gear to said input shaft and said first driven gear to said drive shaft; a one-way overrunning clutch connecting the other of said first drive gear to said input shaft and said first driven gear to said drive shaft, means fixedly connecting one of said second drive gear to said input shaft and said second driven gear to said drive shaft and a centrifugal clutch for selectively drivingly connecting the other of said input shaft to said second drive gear and said second driven gear to said drive shaft, said centrifugal clutch including a drum fixed to one of said gear and said shaft included in the other of said input shaft which is connectable to said second drive gear and said second driven gear which is connectable to said drive shaft, a driver fixed to the other of said gear and said
Claim 33 continued shaft included in the other of said input shaft which is connectable to said second drive gear and said second driven gear which is connectable to said drive shaft, and at least one clutch shoe movably mounted on said driver for movement into engagement with said drum.
34. A marine propulsion device comprising an input shaft drivingly connected to a power source, a lower unit having a rotatably mounted drive shaft offset from said input shaft, a propeller shaft rotatably mounted in said lower unit and carrying a propeller, means drivingly connecting said drive shaft to said propeller shaft, and a two-speed transmission drivingly connecting said input shaft to said drive shaft and including first drive and driven gears in meshing engagement, the gear ratio of said first drive gear to said first driven gear having a first value, means fixedly connecting one of said first drive gear to said input shaft and said first driven gear to said drive shaft, a one-way overrunning clutch connecting the other of said first drive gear to said input shaft and said first driven gear to said drive shaft, second drive and driven gears in meshing engagement, the gear ratio of said second drive gear to said second driven gear having a second value greater than said first value, means fixedly connecting said second driven gear to said drive shaft, and a centrifugal clutch for selectively drivingly connecting said second drive gear to said input shaft, said centrifugal clutch including a drum fixed to one of said input shaft and said second drive gear, a driver fixed to the other of said input shaft and said second drive gear, and at least one clutch shoe movably mounted on said driver for movement into engagement with said drum.
35. A marine propulsion device comprising an input shaft drivingly connected to a power source, a lower unit having a rotatably mounted drive shaft offset from said input shaft, a propeller shaft rotatably mounted in said lower unit and carrying a propeller, means drivingly connecting said drive shaft to said propeller shaft, and a two-speed transmission drivingly connecting said input shaft to said drive shaft and including first drive and driven gears in meshing engagement, the gear ratio of said first drive gear to said first driven gear having a first value, second drive and driven gears in meshing engagement, the gear ratio of said second drive gear to said second driven gear having a second value greater than said first value, means fixedly connecting one of said first drive gear to said input shaft and said first driven gear to said drive shaft, a one-way overrunning clutch connecting the other of said first drive gear to said input shaft and said first driven gear to said drive shaft, means fixedly connecting said second drive gear to said input shaft, and a ccntrifugal clutch for selectively drivingly connecting said second driven gear to said drive shaft, said centri-fugal clutch including a drum fixed to one of said drive shaft and said second driven gear, a driver fixed to the other of said drive shaft and said second driven gear, and at least one clutch shoe movably mounted on said driver for movement into engagement with said drum.
36. A two-speed transmission including an input shaft adapted for connection to a power source, a drive shaft, including first drive means for selectively drivingly connecting said input shaft and said drive shaft and including a drive gear, a driven gear in meshing engagement with said drive gear, and a one-way overrunning clutch drivingly connecting said input shaft and said drive shaft through said drive and driven gears when the rotational speed of said input shaft is less than a predetermined value, said first drive means having an input-output speed ratio with a first value, and second drive means for selectively drivingly connecting said input shaft and said drive shaft when the rotational speed of said input shaft is greater than said predetermined value, said second drive means including a selectively actuatable clutch for drivingly connecting said input shaft and said drive shaft, said second drive means having an input-output speed ratio with a second value greater than said first value.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US72937976A | 1976-10-04 | 1976-10-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1081005A true CA1081005A (en) | 1980-07-08 |
Family
ID=24930775
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA283,047A Expired CA1081005A (en) | 1976-10-04 | 1977-07-19 | Two-speed transmission |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5345900A (en) |
| CA (1) | CA1081005A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE412565B (en) * | 1978-10-02 | 1980-03-10 | Karlstad Mekaniska Ab | MARINT PROPELLER DEVICE |
| JPS6091598U (en) * | 1983-11-30 | 1985-06-22 | スズキ株式会社 | Outboard motor |
| JP2651771B2 (en) * | 1992-10-05 | 1997-09-10 | 株式会社三協精機製作所 | Motor drive |
-
1977
- 1977-07-19 CA CA283,047A patent/CA1081005A/en not_active Expired
- 1977-09-29 JP JP11727777A patent/JPS5345900A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6141798B2 (en) | 1986-09-17 |
| JPS5345900A (en) | 1978-04-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |