US2246206A - Outboard motor - Google Patents

Description

June 1941. R. J. HERRINGTON 2,246,206

OUTBOARD MOTOR Filed Oct. 2, 1939 v 2 Sheets-Sheet I Even for June 1941- R. J. HERRINGTON 2,246,206

OUTBOARD MOTOR Filed 001;. 2, 1939 2 Sheets-Sheet 2 Patented June 17, 1941 'UNHTE STATES PATENT OFFICE 11 Claims.

My present invention relates to outboard motors, and more particularly to the under-water structures of such motors; the main object of this invention being the forming in such substructure, an improved water circulating pump for the engine's cooling system.

Those familiar with the outboard engine art recognize that one of the greatest problems in this art has always been the cooling of the internal combustion engine power-head throughout a wide range of engine speeds. For accomplishing the circulation of cooling fluid through the power-head, various forms of circulating'devices or pumps have been resorted to, among which are the well known plunger type, the centrifugal type, and the spiral vane or screw type. All these, when reduced to sizes consistent with efiicient stream-lining design practice of the under-water or substructure, fail to provide satisfactory cooling, particularly at very low engine speeds, such as employed for trolling. As a consequence of this general lack of capacity of cooling pumps in outboard motors, prolonged operation at very low speeds, such as used in trolling, would hitherto usually result in overheating of the engine, which presented a serious hazard, and has been in a large part responsible for the widespread uses of trolling attachments and the like, which would permit high speed operation of the engine at low boat speed.

In an attempt to obtain the maximum possible eificiency from previous circulating pump designs in the outboard motor industry, it has been common practice to fit the pump parts very closely, and this practice has resulted in a great deal of service troubles caused by scoring of the parts by sand drawn through the pump with the water.

The pump of the present invention utilizes and combines a simple screw or spiral vane type of impeller with a simple centrifugal type impeller, in such a manner that the screw or spiral vane impeller feeds water to the eye portion of the centrifugal impeller. These spiral vane and centrifugal type impellers are mounted directly on the drive shaft within cavities formed therefore in the substructure casing and, in accordance with the preferred example herein illustrated, the spiral and centrifugal type impellers are integrally formed and arranged with the spiral vane impeller above the centrifugal impeller.

Not only is my present fiuid circulating structure very simple, and low in original cost, but it has the further advantage of being of ample capacity to efficiently cool an outboard motor throughout its entire speed range, even when made of small size consistent with the best stream-lining practice, and with the parts fit with suificient clearance that ordinary sand will be passed without causing any serious damage. Since the present pump is low in original cost, practically free of maintenance, and furnishes an ample supply of cooling fluid even at the very lowest trolling speeds, it appears that this pump has solved a problem of long standing in the outboard motor field.

The above, and numerous other important objects of the invention will be made apparent from the following specification, claims, and appended drawings.

Referring to the drawings:

Fig. 1 is a view in side elevation with some parts broken away and some parts shown in section of an outboard motor incorporating the invention;

Fig. 2 is an enlarged fragmentary view with some parts shown in axial section of the underwater .or substructure of the motor of Fig. 1;

Fig. 3 is a transverse sectional view taken on the irregular line 3-3 of Fig. 2;

Fig. 4 is a detail-planned view of the centrifugal impeller with the bearing sleeve portion thereof, sectioned as on the line 44 of Fig. 5;

Fig. 5 is a detailed view showing the centrifugal impeller in side elevation, the bearing sleeve and spiral vane impeller portionbeing broken away;

Fig. 6 is a bottom-planned view of the centrifugal impeller; and

Fig. 7 is a transverse sectional view taken on line 'l'l of Fig. 2.

The power-head of the outboard engine illustrated, being of conventional character, will be only briefly described. This power-head indicated as an entirety by 8 incorporates a pair of cylinders 9 that are formed with cooling fiuid circulating jackets l0, and equipped with suitable pistons II. The cylinders 9 are horizontally disposed and the pistons Ill thereof are anchored by connecting rods I2 to opposite throws to a vertically disposed crank shaft l3 that is suitably J'ournaled in bearings I4 in the engine's crank case I5.

Suitably coupled to the lower end of the'crank shaft I3 is a downwardly extending drive shaft I6, which drive shaft is enclosed within a tubular supporting housing I! to the lower end of which housing is anchored the under-water or substructure housing IB. This substructure housing I8 is formed by upper and lower housing sections A and B respectively, that are secured together by bolts or the like l9 and 28. The upper housing section A is formed just above the dividing line therebetwcen and the lower section B. with a cavitation plate 2|, and the lower section B is formed at its lower portion to receive the propeller shaft 22 and beveled gears 23 connccting the propeller shaft to the drive shaft l6. Thqgears 23 are located within a suitable cavity 24 formed in the bottom portion of the housing section B and the forward end of the propeller shaft 22 is journaled in a bearing 25 mounted directly in the housing section B. The rear-end portion of the propeller shaft 22 is mounted in a bearing 26 formed in a removable closure and bearing supporting member 21. The lower end portion of the drive shaft 16 is journaled in bearings 28 and 29.

The pump rotor, as illustrated, is a unit comprising both the centrifugal and spiral vane by 30. The centrifugal impeller portion of the pump rotor is illustrated as being formed by a cylindrical disc 3| having on its upper surface radially projecting impeller vanes 32. This disclike portion 3| is formed with an elongated upwardly extending sleeve 33 that is press-fitted onto the drive shaft I6 and is in turn formed integrally with the spiral vane 34 of the screw impeller. Above th impeller vane 34 the mounting sleeve 33 is formed with a radially projecting bearing flange 35. The bottom of the impeller disc 3| is shown as provided with very shallow radial vanes 36, which are for the purpose of discharging sand or other foreign substance from under the impeller.

In accordance with the preferred construction herein illustrated, the cavity for the centrifugal type impeller is formed by making an initially open recess 31 in the top of the lower section B, which recess is normally closed at its top by the upper housing section A, when the parts are assembled as illustrated, see Fig. 2. By further reference to Fig. 2, it will be seen that whereas the centrifugal type impeller is located entirely within the lower housing section B, the spiral or screw type is located within the upper housing section A. The cavity 38, for the spiral impeller, is formed by an enlarged axial bore in the bottom portion of the housing section A and which freely receives the spiral vanes 34 and bearing flange 35. The cavity 38 communicates with the axial portion of cavity 31, so that water delivered downwardly by the spiral impeller will be directed to the eye portion of the centrifugal impeller.

The bottom of the centrifrigal impeller is held in slightly spaced relation to the bottom of the cavity 31 by means of a short bearing hub 39, and the entire impeller unit and drive shaft is held against upward movement by engagement of the flange 35 thereof with the end flange of a drive shaft bearing located directly above the cavity 38, and which is inserted through the cavity 38. The bearing 40 also positively prevents wobbling of the intermediate portion of the drive shaft, and thereby insures positive centering of the spiral vane impeller 34 under all conditions of rotation. All of the rotary parts are preferably fit with suflicient clearance to permit the passage of the ordinary run of fine sand without friction or scoring action.

Water is taken into the spiral vane impeller cavity 38 through an inlet port 4| in the front types of impellers and is indicated as an entirety wall of said cavity, from a fluid containing chamber 42, which in turn is provided with a series of inlet passages or ports 43, immediately adjacent opposite sides of the leading edge of the under-water housing. The inlet passages 43 are small in diameter, and relatively great in number, so as to prevent admission of foreign substance of large diameter, and these open forwardly so as to take advantage of the velocity of the housing l8 through the water in delivering water to the spiral vane.

These primary inlets or passages 43 are best shown in Figs. 2 and 3, by reference to which figures it will also be seen that the port 4| is in the nature of a segmental slot.

In practice, I have found that the best results are obtained by locating the final inlet passage 4| to the cavity 38 at approximately the iongitudinal center thereof, as is best illustrated in Fig, 2.

Operation Under operating conditions of the engine, water will enter the primary inlet passages 43 and fill the chamber 42, which is provided near its top with a vent 44. Of course, the forward movement of the device through the water will aid in forcing water through the inlet passages. Water from the chamber 42 will enter the cavity 38 through the final inlet passage 4| and under the combined action of the spiral vane 34 and gravity, will be forced downwardly to the eye portion of the centrifugal impeller, the blades 32 of which will throw this water centrifugally outwardly under pressure to the peripheral portion of the cavity 31. From this point, the water will be discharged from the cavity 31 through the primary outlet passage or port 45, which is formed in the peripheral portion of the upper wall of the cavity 31. Of course the upper wall of the cavity 31 is formed in this instance by the upper housing section A, which is also formed with a receiving chamber 46 into which the water from discharge port 45 is passed, preparatory to delivery to the cylinder water jackets, through a direct conduit or pipe 41.

The very high efficiency of this water circulator or pump under all engine operating conditions, from the slowest possible trolling speed to maximum speed, is brought about by keeping the centrifugal impeller loaded with a generous supply of water at all times. Of course, the spiral vane or screw type of impeller is a very efiicient device for loading the centrifugal impeller, but I have furtherfound that the overall efiiciency of the device is materially increased by positioning the spiral vane impeller above the centrifugal impeller so that the centrifugal impeller is loaded by the combined action of gravity and the spiral vane. Furthermore, I have found that the over-all efliciency of the device is highest when the final inlet passage or port 4|, is located materially below the top of cavity 38 and vane 34.

With the arrangement described, it is also important to note that the chamber 42 which is maintained filled with water, serves as a constant supply reservoir and insures a steady flow of water to the impeller cavity 38, even under conditions when air pockets are momentarily encountered, or under conditions when as a result of large waves, the inlet passages 43 project momentarily out of the water.

Another important advantage of the construction described is the fact that the bottom portion of chamber 42 serves as a trap for heavy foreign substance such as sand. In this respect, attention is directed to the fact that water will enter the primary inlet passages 43 at high velocity, but its velocity will be greatly retarded within the relatively large area chamber 42 and due to this slowing down of the water during its passage from port 43 to port 4|, heavy particles of sand and the like will tend to gravitate to the bottom of chamber 42. In practice, it has been found that most of the heavy foreign sand particles, or the like, entering chamber 42, will gravitate to a level below the port 4! during the passage through the chamber 42, and, of course, this is an important reason for locating the port 4 well above the bottom of said chamber 42.

Another very important reason for locating the final inlet passage M in the spiral vane cavity 38 materially below the top of said spiral vane cavity is as follows:

through the bearing 40 to the hollow portion of the tubular supporting housing Ill.

In practice, it has also been found that any fluid in the tubular housing portion ll, under static conditions, is withdrawn through the bearing 40 under operating conditions. This tendency to draw fluid downwardly through the bear-. ing 40 is also important in that it keeps drawing lubricant through the bearing. In this last respect, attention will be directed to the fact that there is always some leakage of oil downwardly through the lower crank shaft bearing from the crankcase. This oil being sucked through the space between the drive shaft and bearing 40 keeps said bearing 40 well lubricated at all times.

What I claim is:

1. In an outboard motor, the combination with a downwardly extending drive shaft, an underwater housing enclosing the lower end portion of the drive shaft, and a propeller shaft journalled in the lower end portion of the under-water housing and geared to the drive shaft, of a pump rotor mounted on the drive shaft in the intermediate portion of the housing and comprising integrally formed centrifugal type and spiral vane type impellers, said centrifugal type impeller being of relatively much greater diameter than the spiral vane impeller and including circumferentially spaced impeller vanes extending from the eye portion toward the peripheral portion thereof, said integrally formed spiral vane impeller being located directly above and arranged to deliver to the eye portion of the centrifugal impeller, said under-water housing being formed with axially connected cavities for receiving said centrifugal and spiral vane impellers, the walls of said cavities closely embracing their respective impellers,

an inlet passage through the housing to the spiral vane cavity and an outlet passage from the peripheral portion of the centrifugal impeller cavity.

2. The structure defined in claim 1 in which the underwater housing is a two-part structure, and in which the cavity for the spiral vane impeller is located in the upper housing section and is in the nature of an axial bore opening downwardly through the bottom of the upper housing section, and in which the cavity for the centrifugal impeller is formed in and opens upwardly through the top of the lower section, the diameas the top wall of the last named cavity.

ter of the spiai-al vane cavity being materially less than that of the centrifugal impeller cavity and the bottom of said upper housing section, serving 3. In an outboard motor, the combinati n with a downwardly extended drive shaft, an underwater housing enclosing the lower end portion of the drive shaft, and a propeller shaft journaled in the lower end portion of the under-water housin and geared to the drive shaft, of a spiral vane impeller and a centrifugal type impeller mounted on the drive shaft within the intermediate portion of the under-water housing, said centrifugal type impeller being of relatively much greater diameter than the spiral vane impeller and includin circumferentially spaced impeller vanes extending from the eye portion toward the peripheral portion thereof, said spiral vane impeller being located directly above and arranged to deliver to the eye portion of the centrifugal impeller, said under-water housing being formed with axially connected cavities for receiving said centrifugal and spiral vane impellers, the walls of said cavities closely embracing their respective impellers, an inlet passage through the under-water housing to the spiral vane cavity, and an outlet passage from the peripheral portion of the centrifugal impeller cavity.

4. In an outboard motor, the combination with a downwardly extended drive shaft, an underwater housing enclosing the lower end portion of the drive shaft, and a propeller shaft journaled in the lower end portion of the underwater housing and geared to the drive shaft, of a spiral vane impeller and a centrifugal type impeller mounted on the drive shaft within the intermediate portion of the under-water housing, said centrifugal type impeller being of relatively much greater diameter than the spiral vane impeller and including circumferentially spaced impeller vanes extending from the eye portion toward the peripheral portion thereof, said spiral vane impeller being arranged to deliver to the eye portion of the centrifugal impeller, said under-water housing being formed with axially connected cavities for receiving said centrifugal and spiral vane impellers, the walls of said cavities closely embracing their respective impellers, an inlet passage through the under-water housing to the spiral vane cavity,

and an outlet passage from the peripheral porthe said inlet passage opens through the leading edge of the under-water housing.

'7. The structure defined in claim 4 in which the said inlet passage to the spiral vane cavity is in the nature of a narrow slot extending transversely of the axis of the spiral vane cavity.

8. The structure defined in claim 4 in which the under-water housing is formed to provide a reservoir cavity intermediate its leading edge and the said spiral vane cavity, and in which the said inlet passage comprises at least one opening through the leading edge of the under-water housing to the reservoir cavity, said reservoir cavity and a final inlet opening from the reservoir cavity to the spiral vane cavity.

9. The structure defined in claim 4 in which the under-water housing is formed to provide a reservoir cavity intermediate its leading edge and the said spiral vane cavity, and in which the said inlet passage comprises at least one opening throughthe leading edge of the under-water housing to the reservoir cavity, said reservoir cavity and a final inlet opening from the reservoir cavity to the spiral vane cavity, said final inlet opening from the reservoir cavity being in the nature of a transversely extended slot.

10. The structure defined in claim 4 in which the under-water housing is formed to provide a reservoir cavity intermediate its leading edge and the said spiral vane cavity, and in which the said inlet passage comprises at least one opening through the leading edge of the under-water housing to the reservoir cavity, said reservoir cavity and a final inlet opening from the reservoir cavity to the spiral vane cavity, said final inlet opening from the reservoir cavity being in the nature of a transversely extended slot located materially above the bottom of the resertrifugal impeller is formed in and opens upwardly through the top of the lower of said housing sections, the diameter or the spiral vane cavity being materially less than that of the centrifugal impeller cavity and the bottom of the upper 01 said housing sections serving as the top wall of the last named cavity.

RALPH J. HERRINGTON.

that said reservoir cavity will act

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