JP4701843B2 - Outboard motor drive shaft support structure - Google Patents

Description

  The present invention relates to an outboard motor, and more particularly to an outboard motor drive shaft support structure in which a shaft support structure of a drive shaft that transmits engine power to a propeller shaft is improved.

  In general outboard motors, the engine is mounted vertically so that the crankshaft is vertical, the driveshaft housing and gear case are sequentially joined below the engine, and the driveshaft extends downward from the engine crankshaft. While the shaft housing and the gear case are pivotally supported in the vertical direction, the propeller shaft is horizontally supported in the gear case, and the rotation of the drive shaft is transmitted to the propeller shaft via the bevel gear mechanism. Yes.

In conventional outboard motors, regardless of whether they are large or small, the vicinity of the lower end of the drive shaft is rotatably supported by an upper radial bearing and a lower radial bearing provided inside the gear case.
JP 2001-106189 A Japanese Utility Model Publication No. 61-37099

  When transmitting the rotation of the drive shaft to the propeller shaft via the bevel gear mechanism, a radial load in the direction perpendicular to the drive shaft axial direction from the drive bevel gear provided on the drive shaft side, and a thrust along the axial direction of the drive shaft Force is generated. The radial load is mainly received by the lower radial bearing, and the thrust load is received by the end surface of the upper radial bearing (structure of Patent Document 1) or by a dedicated thrust bearing installed on the drive bevel gear (Patent Document 2). Structure).

  However, in the structure that receives the thrust load of the drive shaft at the end surface of the upper radial bearing as in the structure of Patent Document 1, the number of parts increases due to the installation of the upper radial bearing, and the structure around the gear case accompanying the installation of the upper radial bearing Incurs complications.

  In addition, even in a structure in which a dedicated thrust bearing is installed on the drive bevel gear to receive the thrust load as in the structure of Patent Document 2, the number of parts is increased by installing the thrust bearing, and the recess that receives the thrust bearing inside the gear case. As a result, it becomes necessary to process and form a cylindrical bearing seat, which leads to an increase in the number of processing steps.

  In any case, the gear case becomes larger and more complex, and the number of parts increases, and the cooling water passage inside the gear case is positioned around the upper and lower radial bearing holders or on the cavitation plate (stable position directly above the screw propeller). Therefore, it is necessary to secure a dedicated cooling water passage for the convenience of the internal layout, and the structure of the gear case is complicated in this respect as well.

  In order to avoid an increase in the size of the gear case, in the configuration in which the cooling water passage is provided below the cavitation plate, the cooling water may not be sufficiently taken in.

  The present invention has been made to solve the above-described problems, and can reduce the number of parts, reduce the size and simplification of the gear case, reduce the number of processing steps, and improve the cooling efficiency. An object is to provide a drive shaft support structure for an outboard motor.

In order to achieve the above object, a drive shaft support structure for an outboard motor according to the present invention is provided with a gear case at a lower portion of the drive shaft housing, and a drive shaft extending downward from the engine is vertically installed in the drive shaft housing and the gear case. The propeller shaft is supported horizontally in the gear case, a bevel gear mechanism is provided at the intersection of the drive shaft and the propeller shaft, and a vertical drive shaft insertion hole is defined in the gear case. A cylindrical radial bearing that supports the lower end of the drive shaft is disposed at the bottom of the drive shaft insertion hole, a seal member is disposed above the radial bearing, and the drive shaft insertion hole above the seal member an interior space, a cooling water passage for guiding the external water to the water pump On the other hand, the diameter of the upper portion of the radial bearing is increased to form a flange, and the radial bearing is press-fitted into a bearing press-fit portion formed at the bottom of the drive shaft insertion hole, and the flange is formed at the bottom of the bearing press-fit portion. The upper surface of the drive bevel gear of the bevel gear mechanism is brought into contact with the lower surface of the radial bearing .

  According to the drive shaft support structure for an outboard motor according to the present invention, there is one radial bearing for supporting the drive shaft, and a dedicated thrust bearing or the like is not required, so that the number of parts is reduced and formed inside the gear case. Since only one bearing seat has to be performed, the man-hours for processing the gear case are reduced.

  In addition, since the radial bearing becomes one, the gear case can be reduced in size and simplified, and the drive shaft insertion hole itself becomes the cooling water passage, so that the layout of the cooling water passage is improved and the cooling water is improved. Incorporation is ensured, thereby improving the cooling efficiency.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a left side view of an outboard motor to which a drive shaft support structure according to the present invention is applied, and FIG. 2 is an enlarged view of a portion II in FIG.

The outboard motor 1 has, for example, a water-cooled four-cycle single-cylinder engine 2 mounted vertically on the top, and a drive shaft housing 3 and a gear case 4 are sequentially joined to the lower side of the engine 2 with a plurality of bolts 5 and the like. Has been. The engine 2 is mounted so that the cylinder head 6 side faces rearward.

The periphery of the engine 2 is covered with an upper and lower split engine cover 10 including a lower cover 8 and an upper cover 9. The lower cover 8 is fixed to the upper part of the drive shaft housing 3, and the upper cover 9 is detachable. A fuel tank 11 is disposed in front of the engine 2.

The upper part of the drive shaft housing 3 is rotatably held by an annular holder clamp 14 provided integrally with the rear part of the swivel bracket 13, and the swivel bracket 13 is connected to a clamp bracket 16 via a pivot bolt 15. Is fixed to the stern portion of the hull (not shown) by the clamp screw 17. The entire outboard motor 1 can turn upward (tilt up) about the pivot bolt 15.

A drive shaft 19 is rotatably coupled to the lower end of the crankshaft 18 of the engine 2, and the drive shaft 19 extends downward along the inside of the drive shaft housing 3 and the gear case 4, and the lower end of the drive shaft 19 is the inside of the gear case 4. Is supported by a radial bearing 20 provided on the shaft. The radial bearing 20 is, for example, a sliding bearing (metal bearing).

  On the other hand, a horizontally extending propeller shaft 22 is rotatably supported by front and rear radial bearings 23 and 24 inside the gear case 4, and a bevel gear mechanism 25 is provided at the intersection of the drive shaft 19 and the propeller shaft 22. Further, a screw propeller 26 is provided at the rear end of the propeller shaft 22 so as to be integrally rotated by using a spline, a key or the like, the front and rear positions are determined by the flange 27, and the pins 28 are prevented from being detached. The member 29 is a cavitation plate.

The bevel gear mechanism 25 includes a drive bevel gear 31 provided integrally with the lower end portion of the drive shaft 19 and a driven bevel gear 32 provided rotatably at the front end portion of the propeller shaft 22. The front end portion of the propeller shaft 22 is pivotally supported on the radial bearing 23 on the front side via the boss portion 32 a of the driven bevel gear 32.

  In addition, the propeller shaft 22 is provided with a clutch mechanism 34 that selects the driven bevel gear 32 so as to be integrated with the propeller shaft 22 or to be rotatable. The clutch mechanism 34 includes a shifter clutch dock 35 that is integrally rotated with the propeller shaft 22 and is slidable in the axial direction, a clutch spring 36 that constantly biases the shifter clutch dock 35 toward the driven bevel gear 32, and a propeller shaft. 22 is provided with a push rod 37 provided concentrically and slidable in the axial direction at an axial center near the front end. A dock clutch (meshing clutch) 38 is formed between the driven bevel gear 32 and the shifter clutch dock 35.

  On the other hand, the upper end of a long shift rod 40 passing up and down in the drive shaft housing 3 is connected to the rotating link 41 near the joint between the engine 2 and the drive shaft housing 3, and the lower end is suspended in the gear case 4. It reaches the vicinity of the front end of the propeller shaft 22. The rotation link 41 is operated by a shift lever (not shown), and an inclined cam 40a is formed at the lower end of the shift rod 40.

  When the shift rod 40 is in the position shown in FIG. 2, the shifter clutch dock 35 is pressed against the driven bevel gear 32 by the urging force of the clutch spring 36, whereby the dog clutch 38 is coupled and the driven bevel gear 32 is connected to the shifter clutch dock 35. The rotation of the engine 2 (crankshaft 18) is transmitted to the propeller shaft 22 via the drive shaft 19, the bevel gear mechanism 25, and the clutch mechanism 34, and the screw propeller 26 rotates. Thus, the propulsive force of the outboard motor 1 is generated.

  When the shift rod 40 is pushed downward from the position shown in FIG. 2, the slope cam 40a presses the push rod 37 toward the propeller shaft 22, and the push rod 37 resists the urging force of the clutch spring 36 and shifter clutch dock. In order to move 35 away from the driven bevel gear 32, the coupling of the dog clutch 38 is released, the driven bevel gear 32 idles around the propeller shaft 22 and becomes in a neutral state, and the propulsive force of the outboard motor 1 is stopped.

  A hollow propeller shaft chamber 44 on which the propeller shaft 22 is pivotally supported is formed below the inside of the gear case 4, and a bearing housing 45 is liquid-tightly fixed to the rear opening by a plurality of bolts 46. The rear half part protrudes rearward from the bearing housing 45.

  The radial bearing 23 that supports the front end portion of the propeller shaft 22 is, for example, a ball bearing, and is inserted or press-fitted into the front portion of the propeller shaft chamber 44. Further, the radial bearing 24 that supports the intermediate portion of the propeller shaft 22 is, for example, a sliding bearing, and is provided integrally with the bearing housing 45, and a seal member 47 is press-fitted into the rear portion of the radial bearing 24 from the outside. .

  A shift rod insertion hole 50 through which the shift rod 40 is inserted and a vertical hole-shaped drive shaft insertion hole 51 through which the drive shaft 19 is inserted are formed in the upper and lower portions of the gear case 4. The lower ends of the drive shaft insertion holes 51 respectively communicate with the propeller shaft chambers 44.

  The lower part of the drive shaft insertion hole 51 has an inner diameter reduced to form a bearing press-fit portion 53. As shown in FIG. 3 in an enlarged manner, the bearing press-fit portion 53 is formed in a stepped hole shape whose inner diameter is narrowed in three steps downward, and the above-mentioned radial bearing 20 is located at the lower inner diameter portion 53a. The seal member 54 is similarly disposed from above by press-fitting into the uppermost inner diameter portion 53b. The lower end of the drive shaft 19 is rotatably supported by the radial bearing 20.

  The upper portion of the radial bearing 20 is expanded to form a flange 20a. The flange 20a is brought into contact with the lowest step portion 53c of the bearing press-fit portion 53, whereby the vertical position of the radial bearing 20 is determined. . The upper surface of the drive bevel gear 31 that is provided integrally with the lower end of the drive shaft 19 is in contact with the lower surface of the radial bearing 20.

  The press-fitting load (fitting) when the radial bearing 20 is press-fitted into the bearing press-fitting portion 53 (53a) is generated from the drive bevel gear 31 when the drive shaft 19 is rotating forward (forward movement). Is set to be much larger than the thrust force along which the drive shaft 19 is pressed against the engine 2 side.

  On the other hand, as shown in FIG. 4, a pump base 57 is formed on the upper surface of the gear case 4 so as to surround the shift rod insertion hole 50 and the drive shaft insertion hole 51, and the water pump 58 is fixed thereto by four bolts 59. Is done. The water pump 58 has a configuration in which, for example, a rubber multi-blade rotor 61 is enclosed in a resin pump casing 60, and a bottom panel 62 is liquid-tightly attached to the lower surface of the pump casing 60.

  The bottom panel 62 of the water pump 58 is overlaid on the shift rod insertion hole 50 and the upper opening (pump pedestal 57) of the drive shaft insertion hole 51 via the gasket 63, whereby the drive shaft insertion hole 51 is liquidated. Closely closed.

  An internal space of the drive shaft insertion hole 51 above the seal member 54 is a cooling water passage 65, and a plurality of cooling water intakes 66 communicating with the outside are provided below the cooling water passage 65. The cooling water intake 66 opens sufficiently below the cavitation plate 29. A cooling water supply pipe 67 extends upward from the upper surface of the water pump 58 and is connected to the engine 2.

  The drive shaft 19 is passed through the pump casing 60 and the bottom panel 62, and the rotor 61 is directly driven by the rotation of the drive shaft 19. When the rotor 61 is driven, external water enters the cooling water passage 65 from the cooling water intake 66 and is sucked into the water pump 58 through a suction hole (not shown) formed in the bottom panel 62. The cooling water discharged from the water pump 58 is supplied to the engine 2 through the cooling water supply pipe 67 to cool the engine 2.

  In the support structure of the drive shaft 19 configured as described above, the thrust force along the axial direction of the drive shaft 19 generated from the drive bevel gear 31 is in contact with the lower surface of the radial bearing 20 on the upper surface of the drive bevel gear 31. Therefore, it is received by the radial 20 bearing itself. Therefore, the radial bearing 20 also has a function as a thrust bearing, and a thrust bearing dedicated to receiving thrust force, which has been conventionally required, is unnecessary.

  Since the press-fitting load to the bearing press-fit portion 53 (53a) of the radial bearing 20 is set to be much larger than the thrust force, the radial bearing 20 is pulled out from the bearing press-fit portion 53 (53a) by the thrust force. There is no concern.

  Further, the diameter of the upper part of the radial bearing 20 is increased by forming the flange 20a by expanding the diameter of the upper part of the radial bearing 20, and bringing the flange 20a into contact with the lowest step part 53c of the inner diameter part of the bearing press-fit part 53. The position accuracy can be ensured satisfactorily, and there is no fear of generating unnecessary play between the radial bearing 20 and the drive bevel gear 31.

Thus, since the radial bearing 20 that supports the drive shaft 19 also has a function as a thrust bearing, the bearing member that supports the drive shaft 19 needs only one radial bearing 20, and other radial bearings, thrust bearings, etc. Therefore, the number of parts constituting the outboard motor 1 can be greatly reduced.

  In addition, since only one bearing seat (bearing press-fit portion 53) has to be formed inside the gear case 4, the number of man-hours for processing the gear case 4 can be reduced, and the gear case 4 can be reduced in size and simplified. be able to.

  Furthermore, since the drive shaft insertion hole 51 itself is used as the cooling water passage 65, the layout of the cooling water passage 65 is remarkably improved, so that the cooling water intake 66 can be comfortably lowered to a position lower than the cavitation plate 29. Since it can be formed, the cooling water can be reliably taken in, and as a result, the cooling efficiency of the engine 2 can be improved.

  Further, since the upper opening of the drive shaft insertion hole 51 is liquid-tightly closed by the water pump 58, a dedicated lid member or the like is not required, and the structure of the outboard motor 1 can be simplified and assembled easily.

1 is a left side view of an outboard motor to which a drive shaft support structure according to the present invention is applied. The II section enlarged view of FIG. The enlarged view near the drive shaft lower end. The top view of the gear case which follows the IV-IV line of FIG.

Explanation of symbols

1 Outboard motor 2 Engine 3 Drive shaft housing 4 Gear case
19 Drive shaft
20 Radial bearing
20a flange
22 Propeller shaft
25 Bevel gear mechanism
31 Drive bevel gear
51 Drive shaft insertion hole
53c Step
54 Seal member
58 Water pump
65 Cooling water passage

Claims (1)

A gear case is provided at a lower portion of the drive shaft housing, a drive shaft extending downward from the engine is supported in the vertical direction inside the drive shaft housing and the gear case, a propeller shaft is supported in the horizontal direction inside the gear case, and A bevel gear mechanism is provided at the intersection of the drive shaft and the propeller shaft. A vertical drive shaft insertion hole is defined in the gear case, and a cylindrical radial that supports the lower end of the drive shaft at the bottom of the drive shaft insertion hole. arranged a bearing, the inner space of the sealing member is disposed above the radial bearing, above the said sealing member of the drive shaft insertion holes, while the cooling water passage for guiding the external water to the water pump, the The radial bearing is expanded to form a flange, and this radial bearing The bearing is press-fitted into a bearing press-fit portion formed at the bottom of the drive shaft insertion hole, the flange is brought into contact with a step formed at the bottom of the bearing press-fit portion, and the upper surface of the drive bevel gear of the bevel gear mechanism is placed on the lower surface of the radial bearing. A drive shaft support structure for an outboard motor, characterized by contact .

Images