Marine propulsion device bearing lubrication system

Abstract
A marine propulsion device comprising a motor, a unit adapted to be mounted lower on the transom of a boat for pivotal movement with respect thereto about an axis generally vertical direction, the lower unit which includes a box lower gear with the same lubricant, and a helix rotatably supported by the lower gearbox a generally vertical drive shaft rotatably supported in the lower unit which includes an upper end driven by the motor, a lower end drivingly connected to the propeller, an axial bore extending upwardly from the bottom end and which defines a sleeve portion of the shaft, and an opening extending radially through the sleeve portion, and internal threads within the axial bore for pumping lubricant from the gear case bottom upwards through the axial bore to the aperture so that the lubricant flows out through the opening.

Description
Background of the Invention

The invention relates to means for lubricating the bearings of a marine propulsion device, and more particularly to means for lubricating the support bearings of vertical drive shaft of a marine propulsion device.Is known to use an Archimedes screw outside the vertical drive shaft of a propulsion device in order to pump lubricant upward upper support bearings of the drive shaft. See for example, U.S. Patent Holtermann n. No. 3,645,360 and U.S. Patent n FitzGerald. No. 1822573.Also, Becker U.S. Patent n. No. 3,799,291 discloses a vertical drive shaft having an axial bore therein and radial ports for supplying lubricant to the top of the gearbox.
Attention is also directed to the following U.S. patents:Shively: 2569346, September 25, 1951Shively: 2691954, October 19, 1954Ayling: 2963113, December 6, 1960Ellzey: 3428018, February 18, 1969Ellzey: 3520272, July 14, 1970Shimanckas: 3608684, September 28, 1971Croissant: 3931783, January 13, 1976Schiek: 4650430, March 17, 1987
SUMMARY OF THE INVENTION
The invention provides a marine propulsion device comprising an engine, a lower unit adapted to be mounted on the transom of a boat for pivotal movement with respect thereto about an axis generally vertical direction, the lower unit including a thrust bearing, a gear box bottom which has the same lubricant, and a helix rotatably supported by the lower gearbox a generally vertical drive shaft rotatably supported in the lower unit which includes an upper end driven by the motor, a lower end drivingly connected to the propeller, annular, upwardly facing shoulder spaced above the lower end and the participation of the thrust bearing so that the thrust bearing prevents axial movement of the shaft the lower drive unit, an axial bore extending upwardly from the bottom and defining a sleeve portion of the drive shaft, and an opening extending radially from the bore through the sleeve portion and is aligned with axial thrust bearing of the drive shaft, and means for pumping lubricant from the gear case bottom upwards through the axial bore to the aperture so that the lubricant flows out through the opening to lubricate the thrust bearing.In one embodiment, the axial bore having internal threads therein, and the pumping means includes threads.In one embodiment, the axial bore includes internal threads grains.In one embodiment, the marine propulsion device further comprises a spring located in the axial bore, and the spring provides the internal threads.In one embodiment, the marine propulsion device further comprises a radial bearing which is adjacent to the lower end of the drive shaft, rotatably supporting the drive shaft on the lower unit and having an upper end, and the internal threads extending below the upper end of the radial bearing.In one embodiment, the marine propulsion device further comprises seal means located above the thrust bearing and which extends between the lower unit and the drive shaft to prevent the passage of lubricant over the sealing means.In one embodiment, the drive shaft includes an upper segment drive shaft having an upper end driven by the motor, and a lower end, and a segment of the lower shaft having an upper end driven by the lower end segment upper shaft, and a lower end connected to the propeller drive, and the shoulder is located in the segment lower shaft.In one embodiment, the segment of the lower drive shaft has an axial bore therethrough having an upper end, the lower end segment of the upper drive shaft being received in the upper end of the axial hole in the segment lower drive shaft and has in it an axial bore communicating with the axial bore in the segment of the lower drive shaft, the top end of the lower drive shaft includes an annular, generally horizontal surface that surrounds the axis segment Upper drive and defining the shoulder, and the radial opening is in the upper segment drive shaft and communicates with the axial bore in the segment of upper shaft.In one embodiment, the lower end segment of upper shaft is threaded into the upper end of axial bore.In one embodiment, the lower end of the drive shaft is immersed in the lubricant.The invention also provides a marine propulsion device comprising an engine, a lower unit adapted to be mounted on the transom of a boat for pivotal movement with respect thereto about an axis generally vertical direction, the lower unit includes a lower gear box has the same lubricant, and propeller rotatably supported by the lower gearbox a generally vertical drive shaft rotatably supported in the lower unit which includes an upper end driven by the motor , a lower end drivingly connected to the propeller, and an axial bore extending upwardly from the bottom end and which defines a sleeve portion of the drive shaft, and means providing internal threads within the axial bore for pumping lubricating the gearbox bottom upwards through the axial hole.A main feature of the invention is the provision of a marine propulsion device comprising a vertical drive shaft includes an axial bore and a radially extending opening communicating with the axial bore and being axially aligned with a thrust bearing which prevents axial movement of the drive shaft, and means for pumping lubricant from the gear case bottom upwards through the axial bore to the aperture so that the lubricant flows out through the opening to lubricate the bearings thrust. Compared to the prior art, this arrangement is a more efficient means to lubricate the thrust bearing because the lubricant is supplied to the interior of the thrust bearing in place of outward thrust bearing. This is more efficient because a naturally thrust bearing acts as a pump and the oil pump miniature its inner diameter and its outer diameter. Accordingly, it is more efficient to supply oil into a thrust bearing on the outside of a thrust bearing.Another main feature of the invention is the provision of a marine propulsion device as described above, in which the drive shaft is rotatably supported by a radial bearing located beneath the thrust bearing in place above the bearing thrust. Since the radial bearing is below the thrust bearing, the lubricant flows down from the thrust bearing lubricating radial bearing.Another main feature of the invention is the provision of a marine propulsion device comprising a vertical drive shaft includes an axial bore and a radially extending opening communicating with the axial bore, and means providing internal threads in the hole axial pumping lubricant from the bottom of the gearbox upwards through the axial bore to the aperture so that the centrifugal force causes the lubricant to flow out through the opening. Because the wires are located inside the drive shaft, instead of out of the drive shaft, as is known in the art, the yarns may extend below the lower radial bearing supporting the drive shaft. This permits oil pumping even when the oil level in the lower gearbox is low, ie below the upper end of the lower radial bearing. Preferably, the internal threads are provided by a spring located in the axial bore.Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings.
DESCRIPTION OF THE DRAWINGS
. Figure 1 is a side elevational view of a marine propulsion device embodying the invention;. Figure 2 is an enlarged fragmentary view in side elevation, partly in cross section, of the marine propulsion device.. Figure 3 is a view taken along line 3 - 3 Fig. Two.Before one embodiment of the invention is explained in detail, it is 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 illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Furthermore, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be construed as limiting
DESCRIPTION OF THE PREFERRED EMBODIMENT
A marine propulsion device 10 embodying the invention is illustrated in the drawings. While the marine propulsion device is illustrated outboard, it should be understood that the invention is also applicable to other types of marine propulsion devices, such as stern drive unitsAs shown in the figure. 1, the marine propulsion device 10 comprises a mounting assembly mounted on the transom of a boat 12. While various suitable mounting assemblies may be used, in the illustrated construction, the mounting assembly includes a transom bracket 14 fixedly mounted on the transom 12 and a swivel bracket 16 mounted on transom bracket 14 for pivotal movement with respect thereto with a generally horizontal tilt axis 18.The marine propulsion device 10 also comprises a drive unit 20 mounted on the rotating support 16 for pivotal movement relative thereto about an axis generally vertical direction 22 and for common movement therewith about the axis of inclination 18. The propulsion unit 20 includes a motor 24, and a lower unit 26 supporting the motor 24. The lower unit 26 includes a lower gearbox 28 and a propeller 30 rotatably supported by the lower gearbox 28. The lower gearbox 28 contains lubricant, as is known in the art.The marine propulsion device 10 also includes a generally vertical shaft 32 rotatably supported on the lower unit 26 and which includes an upper end driven by the motor 24, and a lower end drivingly connected to the propeller 30. In the preferred embodiment, the lower end of the drive shaft 32 having thereon a drive gear 34 which is drivingly connected to the propeller 30 through a conventional reversible transmission 36.More particularly, in the preferred embodiment, the drive shaft 32 includes an upper segment of the drive shaft 38 having an upper end driven by the motor 24, and a lower end, and the drive shaft 32 also includes a shaft segment lower drive 40 has an upper end driven by the lower end segment of the upper drive shaft 38, and a lower end having thereon the drive gear 34. The segment of the upper drive shaft 38 is preferably made of a corrosion resistant material such as stainless steel, and the segment of the lower drive shaft 40 is preferably made of a support material such as carbon steel. While the lower end segment of the upper drive shaft 38 may be drivingly connected to the top end of the lower drive shaft 40 by any suitable means, in the preferred embodiment, the segment of the lower drive shaft 40 has a therethrough an axial bore 42 having upper and lower ends, and the lower end segment of the upper drive shaft 38 is threaded into the upper end of the axial bore 42. Furthermore, in the preferred embodiment, the drive gear 34 is threaded into the lower end of axial bore 42 therethrough and has an axial bore 44 which communicates with the axial bore 42 in the segment of the lower drive shaft 40.As shown in the figure. 2, the segment of the lower drive shaft 40 is supported on the lower unit 26 by the first or upper radial bearing 46 positioned adjacent the top end of the lower drive shaft 40 and a second or lower bearing radial 48 positioned adjacent the lower end of the segment of the lower drive shaft 40. Furthermore, the top end of the lower drive shaft 40 includes an annular, generally horizontal segment surrounding the upper drive shaft and defining an annular, upwardly facing shoulder 50 and the lower unit 26 includes a thrust bearing or washer 52 located above the upper radial bearing 46 and participation shoulder 50 so that the thrust bearing 52 prevents upward axial movement of the segment of the lower drive shaft 40 in the lower unit 26. More particularly, as shown in Fig. 2, the thrust bearing 52 engages the step 50 through the thrust washer 54 and the lower thrust bearing 52 is supported by the lower unit 26, upper thrust washer 56 that is held in place by a ring 58 retainer. Other means to retain the thrust bearing 52 can be employed and are known in the art.In the preferred embodiment, the marine propulsion device 10 also comprises sealing means 60 located above the thrust bearing 52 and which extends between the lower unit 26 and the segment of the upper drive shaft 38 to prevent the passage of lubricant above the sealing means 60.The marine propulsion device 10 further comprises means for supplying lubricant from the lower gearbox 28 to the thrust bearing 52 and the upper radial bearing 46. These means include the axial bore 44 in the drive gear 34 and the axial bore 42 in the segment of the lower drive shaft 40. This means also includes, in the segment of the upper drive shaft 38, an axial bore 62 (see Fig. 2) communicating with the axial bore 42 in the segment of the lower drive shaft 40 and defines a sleeve portion 64 segment upper drive shaft 38, and one or more openings 66 (see FIGS. 2 and 3) that extends radially from the bore 42 through the sleeve portion 64 and is aligned with the thrust bearing 52 axially drive shaft 32. The lubricant supply means further includes means for pumping lubricant from the lower gear box 28 upwardly through the axial bores 44, 42 and 62 to the openings 66 so that the lubricant flows out through the openings 66 to lubricate the thrust bearing 52 and the upper radial bearing 46.While various suitable pumping means can be employed, in the preferred embodiment, the axial bore 42 in the segment of the lower drive shaft 40 which has internal threads, and the pumping means includes threads. Preferably, the strands extend below the upper end of the lower radial bearing 48. Furthermore, in the preferred embodiment, the threads are provided by a spring 68 located within the axial bore 42 and caught between the upper end of the drive gear 34 and the lower end segment upper drive shaft 38. In alternative embodiments, the yarns may be an integral part of the segment of the lower drive shaft 40, or may be formed in an insert (made of any suitable material) into the bore 42.When the marine propulsion device 10 is operating, the lubricant in the lower gearbox 28 is pumped upwardly through the axial bores 44, 42 and 62 by the spring 68. This is indicated by arrows in Fig. Two. When the lubricant reaches the radially extending apertures 66, the lubricant is pumped out through the openings 66 or by the forces of pumping up the lubricant or by centrifugal force. The oil then flows out through the thrust bearing 52 and then down to the upper radial bearing 46. Therefore, both the thrust bearing 52 and the upper radial bearing 46 are lubricated.Various features of the invention are set forth in the following claims.

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