JP2013107604A - Support structure of gear of outboard motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain tooth contact of a forward gear and a driving gear in a proper state, even if the big load is applied to the forward gear, in a reversing mechanism of the outboard motor which has the driving gear and the forward gear engaging therewith.SOLUTION: A support structure of the gear of the outboard motor of a counter rotation specification has: a driving gear that rotates by the rotation power transmitted from the engine; a forward gear 52 that has a cylindrical structure that penetrates the back and forth direction and is disposed at a rear side of the driving gear; a propeller shaft 29 to which the propulsive propellers are attached and rotatably disposed penetrating through the forward gear 52; a tapered roller bearing 34 provided between the inner periphery of forward gear 52 and the periphery of propeller shaft 29; and a precompression giving member 54 that provides the backward precompression to the forward gear 52.

Description

  The present invention relates to a gear support structure for an outboard motor. More specifically, the present invention relates to a support structure for a gear (forward gear) that transmits rotational power to a propeller shaft when moving forward in a reverse rotation mechanism of an outboard motor of counter rotation (C / R) specification.

  Conventional outboard motors transmit the rotation power of the engine, the propeller shaft provided with a propeller for propulsion, and the rotation of the propeller shaft while transmitting the rotation of the drive shaft to the propeller shaft in an intermittent manner. And a reverse rotation mechanism for switching. The reverse rotation mechanism includes a drive gear provided on the drive shaft, a forward gear and a reverse gear that mesh with the drive gear and rotate in opposite directions, and a clutch mechanism that transmits any one of the forward gear and the reverse gear to the propeller shaft. Including. When the rotation of the forward gear is transmitted to the propeller shaft, the outboard motor moves forward. Further, when the rotation of the reverse gear is transmitted to the propeller shaft, the outboard motor moves backward. As described above, the forward / backward movement of the outboard motor can be switched by switching whether the rotational power is transmitted via the forward gear or the reverse gear. In general, the propulsive force required when the marine vessel moves backward is smaller than that when the marine vessel moves forward. For this reason, the load applied to the reverse gear during reverse travel is smaller than the load applied to the forward gear during forward travel. Therefore, the reverse gear support structure can be simplified compared to the forward gear support structure.

  By the way, in order to obtain a large propulsive force, a ship such as a large motor boat may be equipped with a plurality of outboard motors. Since the outboard motor is configured to generate propulsion by rotating the propeller, yawing may occur in the ship due to the reaction force of the rotation of the propeller. Therefore, in order to prevent or suppress yawing, when multiple outboard motors are mounted on a ship, an outboard motor with a regular rotation specification (hereinafter referred to as “R / R specification”) and a counter rotation specification (hereinafter referred to as “R / R specification”). In some cases, a configuration in which both outboard motors of “C / R” specification are mounted is used. The propeller and propeller shaft of the R / R specification outboard motor rotate rightward when viewed from the rear during forward travel, and the propeller and propeller shaft of the C / R specification outboard motor rotate counterclockwise. As described above, since the rotation direction of the propeller is opposite between the R / R specification outboard motor and the C / R specification outboard motor, the reaction force of the rotation of the propeller is offset. Therefore, yawing is prevented or reduced.

  Some C / R-specific outboard motors have the same configuration as that of the R / R-specific outboard motor, such as an engine, a drive shaft, and a reverse rotation mechanism. By adopting such a configuration, it is possible to share the configuration, parts, and the like between the R / R specification outboard motor and the C / R specification outboard motor. In such a C / R specification outboard motor, the rotation direction of the engine and the drive shaft is the same as that of the R / R specification outboard motor. For this reason, the relationship between the rotation direction of the forward gear and the reverse gear and the forward / backward direction of the outboard motor is opposite between the R / R specification outboard motor and the C / R specification outboard motor. Therefore, in the C / R specification outboard motor, the reverse gear of the R / R specification outboard motor functions as a forward gear, and the forward gear of the R / R specification outboard motor functions as a reverse gear.

  In a general R / R specification outboard motor, a forward gear is provided on the front side of the drive gear, and a reverse gear is provided on the rear side of the drive gear. For this reason, in an outboard motor of R / R specifications, when a large load is applied to the forward gear when moving forward, a force that causes the forward gear to be displaced rearward is applied by this load. Further, when the outboard motor moves forward, a force that is pushed forward by the propeller propulsion force is applied to the propeller shaft. For this reason, the force that displaces the forward gear to the rear side is canceled by the force that pushes the propeller shaft to the front side. On the other hand, in a C / R outboard motor, a forward gear is provided on the rear side of the drive gear. When the outboard motor moves forward and a large load is applied to the forward gear, a force that displaces the forward gear acts on the forward gear due to the load. Since this force is in the same direction as the force applied to the propeller shaft, it is not canceled out. As a result, the forward gear may be displaced forward and approach the drive gear, and the tooth contact may change. In particular, there is a risk that the forward gear and the drive gear mesh in a so-called “bottom contact” state. If it does so, there exists a possibility that durability of a forward gear may fall.

  Patent Document 1 discloses a configuration for improving the workability of attaching and detaching components disposed inside the gear housing and facilitating adjustment of the tooth contact of the bevel gear. However, Patent Document 1 does not disclose a configuration for maintaining an appropriate tooth contact when a load is applied to the bevel gear.

Japanese Patent Laid-Open No. 11-268689

  In view of the above situation, the problem to be solved by the present invention is that in the reverse rotation mechanism of the outboard motor, even when a large load is applied to the forward gear, the forward gear is displaced and the tooth contact with the drive gear is lost. It is to prevent or suppress the change and improve the durability of the forward gear. In particular, in a reverse rotation mechanism of a C / R outboard motor, the forward gear is prevented or suppressed from being displaced forward to prevent or suppress a change in tooth contact between the forward gear and the drive gear. To improve the performance.

  In order to solve the above-described problems, the present invention provides a support structure for an outboard motor of counter rotation specifications (C / R specifications), a drive gear that is rotated by rotational power transmitted from a rotational power source, It has a cylindrical structure that penetrates in the direction, and a forward gear that is disposed on the rear side of the drive gear and meshes with the drive gear, and a propeller for propulsion are attached, and can rotate through the forward gear A propeller shaft disposed; a conical roller bearing provided between an inner periphery of the forward gear and an outer periphery of the propeller shaft; and a forward preload applied to the forward gear via the conical roller bearing. And a preload applying member.

  The forward gear is a gear that transmits rotational power from the rotational power source to the propeller shaft during forward travel.

  The preload applying member is a shim formed in an annular shape.

  A rib projecting radially outward is formed on the outer periphery of the propeller shaft, the conical roller bearing is disposed on the rear side of the rib, and the preload applying member is disposed between the rib and the conical roller bearing. It is arranged in that.

  The conical roller bearing is characterized in that the apex side of the conical roller is directed rearward.

  According to the present invention, the preload application member interposed between the propeller shaft and the forward gear applies the preload to the forward gear toward the rear in the traveling direction. Of the force acting on the forward gear, the component force acting so as to displace the forward gear forward is offset by the preload of the preload application member. For this reason, the forward gear is prevented from being displaced forward, and the positional relationship between the forward gear and the drive gear is prevented from changing. Therefore, since the contact state between the forward gear and the drive gear can be maintained in an appropriate state, it is possible to prevent a decrease in the durability of the forward gear.

FIG. 1 is a side view showing a configuration of an outboard motor according to an embodiment of the present invention. FIG. 2 is a partial cross-sectional view schematically showing the internal structure of the outboard motor according to the embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing the internal configuration of the lower unit of the outboard motor according to the embodiment of the present invention. FIG. 4 is an enlarged cross-sectional view showing the reverse rotation mechanism and the vicinity thereof in the lower unit of the outboard motor according to the embodiment of the present invention. FIG. 5 is a cross-sectional view schematically showing the support structure of the forward gear, and is an enlarged view of a part extracted from FIG. FIG. 6 is an exploded perspective view schematically showing the configuration of the propeller shaft and the reverse rotation mechanism.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. An outboard motor according to an embodiment of the present invention (hereinafter abbreviated as “main outboard motor 1”) is an outboard motor of C / R specifications. That is, when the propeller 39 rotates counterclockwise as viewed from the rear, the outboard motor 1 moves forward. The outboard motor 1 may be an outboard motor dedicated to the C / R specification, and corresponds to both the R / R specification and the C / R specification (= the outboard motor whose specification can be changed). ).

  First, the overall configuration of the outboard motor 1 will be described with reference to FIGS. FIG. 1 is a side view schematically showing the configuration of the outboard motor 1. FIG. 2 is a partial cross-sectional view schematically showing the configuration of the outboard motor 1. FIG. 3 is a cross-sectional view schematically showing the internal structure of the lower unit 103 of the outboard motor 1. For convenience of explanation, the directions of “front”, “rear”, “right”, “left”, “upper”, and “lower” of the outboard motor 1 are based on the direction of the ship 9 to which the outboard motor 1 is attached. The same applies to the orientation of each member constituting the outboard motor 1. In each figure, the front side of the outboard motor 1 is indicated by an arrow Fr, the rear side is indicated by an arrow Rr, the upper side is indicated by an arrow Tp, and the lower side is indicated by an arrow Bt. As shown in FIGS. 1 and 2, the outboard motor 1 is used with its front side fixed to a stern plate 91 (transam board) of the ship 9.

  The outboard motor 1 includes an engine unit 101 located on the uppermost side, a mid unit 102 located on the lower side, and a lower unit 103 located on the lowermost side. Cover members 17 and 18 are attached to the engine unit 101 and the mid unit 102, respectively. The devices disposed inside each of the devices are covered with cover members 17 and 18.

  The engine unit 101 is provided with an engine 11 as a rotational power source. The engine 11 is arranged in a posture in which the crankshaft is substantially vertical. The engine 11 is supported by an engine base 12 provided at the lower part of the engine unit 101. For example, a V-type engine is applied to the engine 11. For example, the V-type engine is arranged in such a manner that the crankshaft is located on the front side and the cylinder and the piston are located on the rear side. An actuator 13 is arranged at the front lower part of the engine unit 101. The actuator 13 operates a reverse rotation mechanism 5 (described later) to switch the forward, reverse, and neutral of the outboard motor 1. The actuator 13 can rotate an upper shift rod 14 (described later) by a predetermined angle in both forward and reverse directions. In addition, the actuator 13 should just be an apparatus which can perform the said operation | movement, and a specific structure is not limited. Therefore, various known actuators can be applied. In addition, the engine unit 101 is provided with an engine control unit (ECU) for controlling the engine 11, an intake device for taking in combustion air, and the like (all not shown).

  The mid unit 102 accommodates a drive shaft 21, a cooling water tank 24, an oil pan 25 for lubricating oil, a cooling water pump 26, and the upper shift rod 14. The drive shaft 21 is arranged so that its axial direction is substantially vertical and penetrates the mid unit 102 in the vertical direction. The upper end portion of the drive shaft 21 is coupled to the crankshaft of the engine 11. The drive shaft 21 is rotated by the rotational power of the crankshaft of the engine 11 being transmitted. The lower end portion of the drive shaft 21 protrudes further from the lower side of the mid unit 102 and enters the lower unit 103. The water tank 24 is disposed adjacent to the rear side of the drive shaft 21 in the upper part of the mid unit 102. The oil pan 25 is disposed on the rear side of the water tank 24. A cooling water pipe 28 is drawn downward from the bottom of the water tank 24. The lower end of the cooling water pipe 28 is connected to the cooling water pump 26. The cooling water pump 26 is connected to an intake port 38 provided in the lower unit 103 via an intake pipe 37. The cooling water pump 26 sucks water from the outside through the water intake 38 and the water intake pipe 37 and supplies the water to the water tank 24 through the cooling water pipe 28. The upper shift rod 14 is disposed on the front side of the drive shaft 21. The upper shift rod 14 is substantially parallel to the drive shaft 21 and is provided so as to be rotatable with respect to the mid unit 102. An upper end portion of the upper shift rod 14 is connected to the actuator 13, and a lower end portion of the upper shift rod 14 is connected to a lower shift rod 27 (described later) via a gear, for example. The upper shift rod 14 rotates by a predetermined angle in the front-rear direction by the operation of the actuator 13, and transmits the operation of the actuator 13 to the lower shift rod 27.

  In particular, as shown in FIG. 3, the lower unit 103 is provided with a lower portion of the drive shaft 21, a propeller shaft 29, a lower shift rod 27, and the reverse rotation mechanism 5. The reverse rotation mechanism 5 is configured between the drive shaft 21 and the propeller shaft 29. The drive shaft 21 and the propeller shaft 29 are connected by the reverse rotation mechanism 5 so that the rotational power can be intermittently and reversely reversed. A propeller 39 for propulsion is attached to the rear end portion of the propeller shaft 29. Since the outboard motor 1 has C / R specifications, the propeller 39 is configured to generate a propulsive force that moves the outboard motor 1 forward when it rotates counterclockwise as viewed from the rear side. If the outboard motor 1 is compatible with both R / R specifications and C / R specifications, the propeller shaft 29 has a propeller 39 corresponding to the R / R specifications and a C A propeller 39 corresponding to the / R specification is attached in a replaceable manner. When the outboard motor 1 is set to the C / R specification, a propeller 39 that generates a propulsive force that moves the outboard motor 1 forward when the counterclockwise rotation is viewed from the rear side is attached. On the other hand, when the outboard motor 1 is set to the R / R specification, a propeller 39 that generates a propulsive force that moves the outboard motor 1 forward when attached to the right when viewed from the rear side is attached. In addition, a water intake port 38 for taking in cooling water is provided at the front of the lower unit 103 (see FIG. 1).

  As shown in FIG. 2, a pair of left and right upper mounts 15 are provided on the front edge portion of the engine base 12. In addition, a pair of left and right lower mounts 16 are provided at the front edge of the mid unit 102. The engine unit 101, the mid unit 102, and the lower unit 103 are supported by the upper mount 15 and the lower mount 16 so as to be integrally rotatable about the support shaft of the swivel bracket 19. The engine unit 101 is provided with a steering handle 22 that protrudes forward. The boat operator can rotate the outboard motor 1 in a substantially horizontal direction around the support shaft of the swivel bracket 19 by operating the steering handle 22. Thereby, the traveling direction of the ship can be controlled. Clamp brackets 20 are provided on the left and right sides of the swivel bracket 19. The clamp bracket 20 has a configuration that can be fixed to the stern plate 91 (transam board) of the ship 9. The clamp bracket 20 is supported so as to be rotatable about a tilt axis whose axis is directed in the left-right direction.

  Next, details of the configuration of the lower unit 103 will be described with reference to FIGS. FIG. 4 is an enlarged cross-sectional view showing the reverse rotation mechanism 5 and the vicinity thereof in the lower unit 103. FIG. 5 is a sectional view schematically showing the support structure of the forward gear 52, and is an enlarged view of a part extracted from FIG. FIG. 6 is an exploded perspective view schematically showing the configuration of the propeller shaft 29 and the reverse rotation mechanism 5.

  The lower unit 103 has a housing 23 in which a predetermined space is formed. The housing 23 is made of, for example, a light metal and is manufactured by a die casting method. The lower unit of the drive shaft 21, the propeller shaft 29, the lower shift rod 27, and the reverse rotation mechanism 5 are accommodated in the housing 23 of the lower unit 103. The reverse rotation mechanism 5 includes a drive gear 51, a forward gear 52, a reverse gear 53, a dog clutch 58, a connector rod 59, and a shift slider 60.

  The lower end portion of the drive shaft 21 enters the inside of the housing 23 of the lower unit 103. And the drive gear 51 is attached to the lower end part of the drive shaft 21 so that it may rotate integrally. A bevel gear is applied to the drive gear 51. Further, a forward gear 52 and a reverse gear 53 are rotatably supported on the casing 23 of the lower unit 103 via bearings. Specifically, the forward gear 52 is rotatably supported by the radial bearing 30 and the thrust bearing 31. The reverse gear 53 is rotatably supported by the radial bearing 32 and the thrust bearing 33. A bevel gear is applied to the forward gear 52 and the reverse gear 53. The forward gear 52 and the reverse gear 53 have a cylindrical configuration that penetrates in the front-rear direction. The forward gear 52 has bevel gear teeth formed on the front side. On the other hand, the reverse gear 53 is formed with bevel gear teeth on the rear side. The forward gear 52 and the reverse gear 53 are coaxial, are spaced apart from each other at a predetermined interval in the front-rear direction, and are arranged so that the surfaces on which teeth are formed face each other. The forward gear 52 is disposed on the rear side of the drive gear 51, and the reverse gear 53 is disposed on the front side of the drive gear 51. The forward gear 52 and the reverse gear 53 are always meshed with the drive gear 51, and the rotation of the drive gear 51 is transmitted to rotate in opposite directions. Specifically, when rotational power is transmitted from the engine 11, the forward gear 52 rotates to the left when viewed from the rear, and the reverse gear 53 rotates to the right when viewed from the rear. Furthermore, an engaging portion (not shown) is formed on each of the surfaces of the forward gear 52 and the reverse gear 53 facing each other (= the surface on which teeth are formed). The engaging portion can be engaged with an engaging portion (described later) of the dog clutch 58.

  The propeller shaft 29 is disposed in such a posture that the axis is directed in the front-rear direction. In particular, as shown in FIGS. 3 and 4, the front end portion of the propeller shaft 29 enters the inner periphery of the reverse gear 53 and is rotatably supported by a conical roller bearing 35 provided in front of or in the inner periphery of the reverse gear 53. Is done. The rear portion of the propeller shaft 29 is rotatably supported by a radial bearing 36 provided on the housing 23 of the lower unit 103. The intermediate portion of the propeller shaft 29 penetrates the inner periphery of the forward gear 52 and is rotatably supported by a conical roller bearing 34 provided on the inner periphery of the forward gear 52. Thus, the propeller shaft 29 is rotatably supported by the housing 23, the forward gear 52, and the reverse gear 53 of the lower unit 103 via the bearings. In the conical roller bearing 34 provided on the inner periphery of the forward gear 52, the apex side of the conical roller is directed to the rear side. On the other hand, in the conical roller bearing 35 provided at the front or inner periphery of the reverse gear 53, the apex side of the conical roller is directed to the front side.

  A dog clutch 58 is disposed between the forward gear 52 and the reverse gear 53. The dog clutch 58 has a cylindrical configuration and is attached to the outer periphery of the propeller shaft 29. And although the dog clutch 58 can reciprocate along the front-back direction (= axial direction of the propeller shaft 29), it cannot rotate relatively with respect to the propeller shaft 29, but rotates integrally. An engagement portion (not shown) is formed at the front end portion and the rear end portion of the dog clutch 58. When the dog clutch 58 moves to the rear side, the engaging portion formed at the rear end engages with the engaging portion of the forward gear 52, and the rotation of the forward gear 52 passes through the dog clutch 58 and the propeller shaft 29. Is transmitted to. On the other hand, when the dog clutch 58 moves forward, the engaging part formed at the front end part engages with the engaging part formed on the reverse gear 53, and the rotation of the reverse gear 53 rotates via the dog clutch 58 through the propeller shaft. 29. When the dog clutch 58 is positioned between the forward gear 52 and the reverse gear 53, the engaging portion of the dog clutch 58 is not engaged with any of the engaging portions of the forward gear 52 and the reverse gear 53, and the forward gear. Neither the rotation of 52 nor the reverse gear 53 is transmitted to the propeller shaft 29.

  As shown in FIGS. 3, 4, and 6, the front portion of the propeller shaft 29 is formed hollow. A connector rod 59 is disposed inside the propeller shaft 29 so as to be able to reciprocate in the front-rear direction. Furthermore, the hollow part of the propeller shaft 29 is formed with an opening that communicates the outer periphery and the inner periphery. The rear end portion of the connector rod 59 and the dog clutch 58 are coupled by a pin member 61 or the like through this opening. A shift slider 60 is coupled to the front end of the connector rod 59. The shift slider 60 converts the rotational motion of the lower shift rod 27 into reciprocating motion, and reciprocates the dog clutch 58. The lower shift rod 27 is rotatably disposed in the lower unit 103. A shift yoke is provided at the lower end of the lower shift rod 27. The shift yoke is a structure that projects laterally. The shift slider 60 is a rod-like member that is long in the front-rear direction. The shift slider 60 is formed with a long hole penetrating in the vertical direction and long in the front-rear direction. Furthermore, a notch is formed in the side of this long hole. The lower end of the lower shift rod 27 is loosely inserted into the elongated hole. The shift yoke of the lower shift rod 27 engages with the notch formed on the side of the long hole.

  With such a configuration, when the actuator 13 operates and the upper shift rod 14 and the lower shift rod 27 rotate, the shift yoke slides the shift slider 60 in the front-rear direction. Then, the dog clutch 58 moves to the front side or the rear side in conjunction with the shift slider 60. For this reason, the rotation direction of the propeller shaft 29 can be switched. Specific embodiments are as follows. When the dog clutch 58 moves rearward, the rotation of the forward gear 52 is transmitted to the propeller shaft 29 via the dog clutch 58, and the propeller 39 rotates counterclockwise to advance the ship 9. When the dog clutch 58 moves forward, the rotation of the reverse gear 53 is transmitted to the propeller shaft 29 via the dog clutch 58, the propeller 39 rotates to the right, and the ship 9 moves backward. Thus, the forward gear 52 transmits rotational power to the propeller shaft 29 during forward travel, and the reverse gear 53 transmits rotational power to the propeller shaft 29 during reverse travel.

  When the engine 11, the drive shaft 21 and the reverse rotation mechanism of the outboard motor 1 have the same configuration as the R / R specification outboard motor, the reverse gear of the R / R specification outboard motor is The forward gear 52 of the outboard motor 1 is used, and the forward gear of the R / R specification outboard motor is the reverse gear 53 of the outboard motor 1. For this reason, when the outboard motor 1 moves forward, the forward gear 52 is subjected to a large load equivalent to the forward gear of the R / R specification outboard motor. Then, due to this load, a “twisting force” acts on the forward gear 52. The front-rear direction component of this twisting force acts in a direction that displaces the forward gear 52 toward the front side. For this reason, when this load increases, the forward gear 52 is displaced forward and approaches the drive gear 51, and the contact between the drive gear 51 and the forward gear 52 becomes excessively strong. If it does so, durability of the reverse gear 53 will fall. When the outboard motor 1 moves forward, the propeller shaft 29 is pressed toward the front side by the propulsive force of the propeller 39. The front / rear direction component of the force that squeezes the forward gear 52 and the force with which the propeller shaft 29 is pressed by the propelling force of the propeller 39 are both forward and are not offset. Therefore, in the outboard motor 1, the force for displacing the forward gear 52 to the front side is reduced by the following structure of the support structure of the forward gear 52, and deterioration of the durability of the forward gear 52 is prevented or suppressed. To do.

  Details of the support structure of the forward gear 52 will be described with reference to FIGS. The forward gear 52 has a support portion 522 formed on the rear side and a tooth portion 521 formed on the front side. The support portion 522 has a cylindrical configuration that penetrates in the front-rear direction. Bevel gear teeth are formed on the front surface of the tooth portion 521. The outer diameter of the tooth portion 521 is larger than the outer diameter of the support portion 522. The forward gear 52 is rotatably supported by the casing 23 of the lower unit 103 by the radial bearing 30 and the thrust bearing 31. Specifically, the radial bearing 30 is disposed between the outer periphery of the support portion 522 of the forward gear 52 and the inner peripheral surface of the housing 23 of the lower unit 103. Further, a thrust bearing 31 is disposed between the rear end surface of the tooth portion 521 of the forward gear 52 (= the back surface of the surface on which the teeth are formed) and the inner peripheral surface of the housing 23 of the lower unit 103. Is done. 4 to 6 show a configuration in which the washer 40 is provided between the casing 23 of the lower unit 103 and the thrust bearing 31, a configuration in which the washer 40 is not provided may be used. Moreover, conventionally known structures can be applied to the radial bearing 30 and the thrust bearing 31. For example, various known radial roller bearings and radial ball bearings (radial bearings) such as a cylindrical roller bearing and a needle roller bearing can be applied to the radial bearing 30. As the thrust bearing 31, various known thrust bearings (thrust bearings) such as a thrust needle roller bearing and a thrust ball bearing can be applied. Thus, the forward gear 52 is supported in a state of being positioned in the radial direction by the radial bearing 30 and is supported in a state of being positioned in the front-rear direction by the thrust bearing 31.

  In particular, as shown in FIG. 5, an annular groove 523 extending along the circumferential direction is formed on the inner peripheral surface of the support portion 522 of the forward gear 52. A retaining ring 41 is fitted into the groove 523. On the other hand, a rib 291 is formed on the outer periphery of the propeller shaft 29. The rib 291 has an annular configuration that protrudes outward in the radial direction and extends in the circumferential direction. The rib 291 is positioned in front of the retaining ring 41 fitted in the forward gear 52 in a state where the propeller shaft 29 and the forward gear 52 are assembled to the housing 23 of the lower unit 103. The rib 291 may be formed integrally with the propeller shaft 29, or may be a structure in which a separate member is assembled. For example, an annular groove extending in the circumferential direction may be formed on the outer peripheral surface of the propeller shaft 29, and a retaining ring may be fitted into the groove. A conical roller bearing 34, a preload applying member 54, a washer 55, and another washer 56 are disposed between the retaining ring 41 and the rib 291. Specifically, a preload application member 54 is provided on the rear side of the rib 291 of the propeller shaft 29, and a washer 55 is provided on the rear side of the preload application member 54. Then, the inner ring 341 of the conical roller bearing 34 is locked to the surface on the rear side of the rib 291 of the propeller shaft 29 via the preload imparting member 54 and the washer 55. Further, another washer 56 is provided on the front side of the retaining ring 41 fitted into the support portion 522 of the forward gear 52. Then, the outer ring 342 of the conical roller bearing 34 is engaged with the retaining ring 41 fitted into the support portion 522 of the forward gear 52 via another washer 56. The conical roller bearing 34 provided on the inner periphery of the forward gear 52 is disposed in a posture in which the apex side of the conical roller is located on the rear side. That is, the conical roller bearing 34 is disposed in such a direction as to receive a compressive force in such a manner that the inner ring 341 is pressed rearward and the outer ring 342 is pressed frontward.

  The preload applying member 54 applies a preload directed rearward to the forward gear 52 via the conical roller bearing 34. For the preload applying member 54, for example, various known annular shims can be applied. The annular shim is disposed between the rib 291 of the propeller shaft 29 and the conical roller bearing 34 in a state compressed in the front-rear direction. That is, in the state where no external force is applied to the shim, the front-rear dimension of the shim is larger than the front-rear dimension of the gap formed between the rim and the washer. Therefore, when the shim is disposed between the rib 291 of the propeller shaft 29 and the conical roller bearing 34, the shim applies a preload to the forward gear 52 to the rear side via the washer 55 and the conical roller bearing 34. Always granted. 4 to 6 show a configuration in which one annular shim is applied as the preload application member 54, the specific configuration and number of the preload application members 54 are not limited. . In short, the preload applying member 54 may be configured to apply a preload to the forward gear 52 to the rear side. Further, FIGS. 4 to 6 show a configuration in which a shim as a preload application member 54 is disposed between the propeller shaft 29 and the washer 55. The position where the preload application member 54 is disposed is The position is not limited. For example, the preload application member 54 may be disposed between the washer 55 and the conical roller bearing 34. Moreover, the structure by which the washer 55 is not provided may be used. In the case where the washer 55 is not disposed, the preload applying member 54 is disposed between the rib 291 of the propeller shaft 29 and the conical roller bearing 34.

  According to such a configuration, the preload applying member 54 interposed between the rib 291 of the propeller shaft 29 and the forward gear 52 constantly applies a preload to the rear side via the conical roller bearing 34. . For this reason, when a force that causes the forward gear 52 to be displaced forward acts, the preload by the preload applying member 54 cancels this force. For this reason, the forward gear 52 is prevented from being displaced forward. That is, when the outboard motor 1 moves forward, the rotational power from the drive shaft 21 is transmitted to the propeller shaft 29 via the forward gear 52. At this time, a “twisting force” acts on the forward gear 52 due to a load between the forward gear 52 and the drive gear 51. In particular, during forward travel, a greater load may be applied than during reverse travel, so that the force for twisting forward gear 52 also increases. And since the front-rear direction component of this twisting force is directed to the front side, a force that displaces to the front side acts on the forward gear 52. Since the forward gear 52 is applied with a preload to the rear side by the preload application member 54, the component force to the front side of the force that squeezes the forward gear 52 is applied to the rear side by the preload application member 54. Is offset by Therefore, the forward gear 52 is prevented from being displaced forward. Thus, since the forward gear 52 can be prevented from being displaced forward, the distance between the forward gear 52 and the drive gear 51 can be properly maintained. That is, for example, excessively strong contact between the drive gear 51 and the forward gear 52 is prevented or suppressed, and an appropriate meshing state is maintained. Therefore, even when a large load is applied to the forward gear 52, it is possible to prevent the durability of the forward gear 52 from being lowered. Further, the smooth operation of the forward gear 52 can be maintained.

  As mentioned above, although each embodiment of this invention was described in detail, the said embodiment is only what showed the example of actualization in implementing this invention. The technical scope of the present invention should not be construed as being limited by this embodiment. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

  For example, in the above-described embodiment, a configuration in which an annular shim is applied as the preload imparting member 54 is shown, but the preload imparting member 54 is not limited to an annular shim. In short, any configuration may be used as long as it is interposed between the propeller shaft 29 and the forward gear 52 and can apply a preload to the forward gear 52 to the rear side. For example, as the preload applying member 54, various elastic bodies, disc springs, coil springs, and the like may be applied. Further, the number of preload application members 54 is not limited. It is appropriately set according to the required preload. Furthermore, the position at which the preload applying member 54 is disposed is not limited to the above embodiment. In short, any position that can apply a preload to the rear side to the forward gear 52 is acceptable.

  The present invention is a technique effective for a gear support structure for an outboard motor of C / R specifications. In particular, this is an effective technique for an outboard motor having a C / R specification in which an engine, a drive shaft, and a reverse rotation mechanism have a configuration common to that of the R / R specification. This technology is effective not only for outboard motors dedicated to C / R specifications but also for outboard motors that support both R / R specifications and C / R specifications.

1: Outboard motor according to an embodiment of the present invention, 5: reverse rotation mechanism, 21: drive shaft, 29: propeller shaft, 291: rib of propeller shaft, 34: conical roller bearing provided on the inner periphery of the forward gear, 39 : Propeller, 41: Retaining ring, 51: Drive gear, 52: Forward gear, 54: Preload application member, 522: Forward gear support

Claims (5)

It is a support structure for the counterrotation outboard motor,
A drive gear that rotates by rotational power transmitted from a rotational power source;
A forward gear having a cylindrical configuration penetrating in the front-rear direction, disposed on the rear side of the drive gear, and meshing with the drive gear;
A propeller shaft to which a propeller for propulsion is attached and rotatably disposed through the forward gear;
A conical roller bearing provided between the inner periphery of the forward gear and the outer periphery of the propeller shaft;
A preload application member that applies a preload to the rear side via the conical roller bearing;
A support structure for an outboard motor gear.   The outboard motor gear support structure according to claim 1, wherein the forward gear is a gear that transmits rotational power from the rotational power source to the propeller shaft during forward travel.   The outboard motor gear support structure according to claim 1, wherein the preload applying member is a shim formed in an annular shape.   A rib projecting radially outward is formed on the outer periphery of the propeller shaft, the conical roller bearing is disposed on the rear side of the rib, and the preload applying member is disposed between the rib and the conical roller bearing. The outboard motor gear support structure according to claim 3, wherein the outboard motor gear support structure is disposed on the outboard motor.   5. The outboard motor gear support structure according to claim 1, wherein the conical roller bearing is disposed such that the apex side of the conical roller faces rearward.

Images