JP2006183694A - Outboard motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce generation of noise caused by torque fluctuation of an engine, and to perform assembling work without troubles. <P>SOLUTION: In this outboard motor 1 wherein a lower case 9 supporting a drive shaft 13 through a bearing and an upper case 8 having a drive shaft through hole 60, are mounted as components, a bush 73 for supporting the drive shaft 13 is mounted on a midway portion of the drive shaft through hole 60, and the drive shaft 13 is connected with the engine 10 through a spline, a damper structure 70 is mounted on the midway portion of the drive shaft 13 to reduce the generation of noise caused by torque fluctuation of the engine 10, and the damper structure 70 is mounted between an abutted face of the lower case 9 and the upper case 8, and the bush 73. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an outboard motor mounted on a small boat such as a motor boat, a yacht or a fishing boat.

  The outboard motor is equipped with an engine that rotates a propeller, and has a lower case in which a drive shaft that transmits power of the engine is supported by a bearing, and an upper casing that has a drive shaft through hole as constituent members. Are splined to the engine (Japanese Patent Laid-Open No. 10-114298).

In such an outboard motor, engine torque fluctuations due to irregular combustion occur. On the other hand, since the propeller tends to rotate constantly due to the inertial force of rotation, an abnormal noise (tooth rattling noise) is generated between the gear on the drive shaft side and the dog clutch on the propeller side. As a solution, there is a technique disclosed in Japanese Patent Publication No. 4-18598.
Japanese Patent Laid-Open No. 10-114298 (pages 1 to 7, FIGS. 1 to 5) Japanese Examined Patent Publication No. 4-18598 (pages 1 to 8, FIGS. 1 to 13)

  By the way, since the drive shaft of the outboard motor is supported by bearings on the lower case side, when assembling the outboard motor, the upper case is attached to the exhaust guide, and the lower case in which the drive shaft is previously assembled is joined. Therefore, since the drive shaft is long enough to pass through the upper case and reach the engine, mounting the lower case is a cumbersome task of inserting the drive shaft into the upper case from a distance.

  In addition, a bush that supports the middle part of the drive shaft is generally provided in the vertical hole through which the drive shaft of the upper case passes. The bush may be installed depending on the installation location of the propeller rotation smoothing device (hereinafter referred to as a damper). Furthermore, there is a risk that it becomes annoying.

  The present invention has been made in view of this point, and an object of the present invention is to provide an outboard motor that reduces the generation of abnormal noise due to engine torque fluctuations and at the same time does not complicate assembly work.

  In order to solve the above problems and achieve the object, the present invention is configured as follows.

The invention according to claim 1 includes, as constituent members, a lower case in which the drive shaft is supported by a bearing and an upper case having a drive shaft through hole, and the drive shaft is supported in the middle of the drive shaft through hole. In an outboard motor in which a bush is provided and the drive shaft is splined to the engine,
In the middle of the drive shaft, a damper structure that reduces the occurrence of abnormal noise due to torque fluctuations of the engine is provided,
The damper structure is an outboard motor provided between a mating surface of the lower case and the upper case and the bush.

  According to a second aspect of the present invention, in the outboard motor according to the first aspect, a water drainage hole communicating with the drive shaft through hole is provided at a position above the bush of the upper case. is there.

  The invention according to claim 3 is the outboard motor according to claim 1 or 2, wherein the drive shaft can be divided at a damper structure portion.

  According to a fourth aspect of the present invention, the outboard motor according to any one of the first to third aspects, wherein the damper structure is disposed above a water pump operated by the drive shaft. It is.

  The invention according to claim 5 is characterized in that the damper structure is disposed below the position of the mount portion provided in the upper case and supporting the propulsion unit on the steering shaft side. 5. The outboard motor according to any one of items 4.

  With the above configuration, the present invention has the following effects.

  According to the first aspect of the present invention, the damper structure that reduces the occurrence of abnormal noise due to engine torque fluctuation is provided in the middle of the drive shaft. The diameter of the drive shaft increases only in the damper structure, and the damper structure is provided between the mating surface of the lower case and the upper case, and the bush. In other words, since the damper structure is arranged below the bush, even if a damper structure having a diameter larger than that of the bush is provided, it is only necessary to insert the drive shaft and attach the lower case as usual, and the difference due to engine torque fluctuations. As well as reducing the generation of noise, the assembly work is not cumbersome.

  According to the second aspect of the present invention, the water intake hole communicating with the drive shaft through hole is provided at a position above the bush of the upper case, so that water can penetrate through the drive shaft from the outside through the water intake hole. The bush and damper structure can be cooled by entering the hole.

  According to the third aspect of the present invention, the drive shaft can be divided at the damper structure, and at the time of assembly, one drive shaft is first inserted into the upper case, and then the other drive integrated with the lower case. Since the shaft can be attached, the trouble of inserting a long drive shaft is reduced, and the assembly is facilitated.

  According to the fourth aspect of the present invention, the damper structure is disposed above the water pump operated by the drive shaft, so that the space above the water pump can be used effectively, and the conventional cooling water passage structure is significantly changed. A damper structure can be installed without it.

  According to the fifth aspect of the present invention, the damper structure is provided in the upper case and disposed below the position of the mount portion that supports the propulsion unit on the steering shaft side, so that the occupied volume is increased by the damper structure. Even so, a conventional steering shaft can be used.

  Embodiments of the outboard motor of the present invention will be described below. The embodiment of the present invention shows the most preferable mode of the present invention, and the present invention is not limited to this.

  FIG. 1 is a side view of an outboard motor mounted on a hull. The outboard motor 1 of this embodiment is attached to the stern plate 100 a of the hull 100 by a clamp bracket 2. A swivel bracket 5 that elastically supports the propulsion unit 4 by upper and lower mount portions 3 a and 3 b is pivotally attached to the clamp bracket 2 so as to be rotatable up and down by a tilt shaft 6.

  The propulsion unit 4 has a housing composed of a cowling 7, an upper case 8 and a lower case 9. The cowling 7 is formed by a top cowl 700 and a bottom cowl 701. The upper mount 3a supports the exhaust guide 11, the lower mount 3b supports the upper case 8, and supports the propulsion unit 4 on the steering shaft side.

  A four-cycle engine 10 is housed in the cowling 7. The upper case 8 is attached to the lower part of the exhaust guide 11. The engine 10 is supported by an exhaust guide 11.

  A crankshaft 12 is disposed in the engine 10 in the vertical direction, and an upper end of a drive shaft 13 that is vertically cut in the upper case 8 is connected to the crankshaft 12. The lower end of the drive shaft 13 is connected to a forward / reverse switching mechanism 14 housed in the lower case 9, and a propeller shaft 15 extends horizontally from the forward / backward switching mechanism 14, and the lower case 9 of the propeller shaft 15 is connected to the lower case 9. A propeller 16 is attached to the rear end portion protruding outward.

  Next, the configuration of the outboard motor according to the present invention will be described with reference to FIGS. 2 is a longitudinal sectional view of the outboard motor, FIG. 3 is an enlarged view of a main part of the outboard motor, FIG. 4 is a perspective view of the damper structure, and FIG. 5 is an exploded perspective view of the damper structure.

  In the propulsion unit 4 of this embodiment, the upper case 8 and the lower case 9 are assembled by joining the mating surfaces 8a and 9a, and the drive shaft 13 is connected to the crankshaft 12 of the engine 10. The drive shaft 13 penetrates the inside of the upper case 8 in the vertical direction, and its lower end reaches the lower part of the lower case 9 and is supported by bearings 39a, 39b, and 39c. A drive bevel gear 20 is fixed to the lower end portion of the drive shaft 13. Passive bevel gears 21 and 22 mesh with the driving bevel gear 20 on the front side and the rear side, respectively. The passive bevel gears 21 and 22 are rotatably attached to the propeller shaft 15. The propeller shaft 15 is rotatably attached to the lower case 9 and a propeller 16 is attached to the rear end thereof.

  A dog clutch 28 is provided between the front passive bevel gear 21 and the rear passive bevel gear 2. When the dog clutch 28 is engaged with the front passive bevel gear 21, Is transmitted to the propeller shaft 15 via the driving bevel gear 20 and the front passive bevel gear 21, the propeller 16 rotates, and the ship on which the outboard motor is mounted moves forward.

  On the other hand, when the dog clutch 28 is engaged with the rear passive bevel gear 22, the rotational force from the drive shaft 13 is transmitted to the propeller shaft 15 via the drive bevel gear 20 and the rear passive bevel gear 22. 16 rotates and the ship moves backward. The dog clutch 28 is operated via a shift cam 31 disposed on the front side of the propeller shaft 15 and a shift rod 32 connected to the upper side of the shift cam 31.

  The shift rod 32 includes an upper rod 32a and a lower rod 32b. The lower end 32a1 of the upper rod 32a and the upper end 32b1 of the lower rod 32b are connected by spline fitting to the connecting cylinder 32c, and can be divided at the positions of the mating surfaces 8a, 9a of the upper case 8 and the lower case 9. Yes.

  A speed detection tube 66 is disposed in the upper case 8. The upper part of the speed detection tube 66 is connected to a speed detection device (not shown) that detects the speed from the water pressure, and the lower part of the speed detection tube 66 is connected to a connection pipe 67 that is detachably attached to the upper case 8. Has been.

  In the lower case 9, a speed detection water channel 68 is formed in the vertical direction, and the speed detection water channel 68 communicates with a water introduction water channel 69 formed in the horizontal direction. The water introduction water channel 69 opens to the front side of the lower case 9, and water enters from the water introduction water channel 69 during cruising, and the speed is increased by the water pressure applied to the speed detection device via the speed detection water channel 68 and the speed detection tube 66. It comes to detect.

Further, a water pump 34 that is a volume change type pump is provided in the middle of the drive shaft 13, and the water pump 34 draws water from a suction port 36 formed in the lower case 9 through a suction passage 37. The water is sucked and discharged into the cooling water passage of the engine 10 through the water supply pipe 38 connected to the discharge port 34a of the water pump 34.
A drive shaft chamber 52 in which the drive shaft 13 is disposed is disposed at the front portion of the upper case 8. Further, a water pump chamber 44 communicating with the drive shaft chamber 52 is disposed below the drive shaft chamber 52. The drive shaft 13 is disposed in the drive shaft chamber 52. The water pump 34 is disposed in the water pump chamber 44.

  An oil pan 46 and an exhaust pipe 53 are disposed above the upper case 8 and behind the drive shaft chamber 52. Further, a muffler 45 is disposed below the oil pan 46.

  The exhaust gas of the engine 10 flows into the muffler 45 through the exhaust pipe 53, and is discharged out of the outboard motor 1 through the exhaust gas passage 54 in the lower case 9 and the exhaust passage 55 of the propeller 16. Yes.

  The outboard motor 1 of this embodiment includes a lower case 9 in which the drive shaft 13 is supported by a bearing and an upper case 8 having a drive shaft through hole 60 as constituent members. The drive shaft through hole 60 is constituted by a water pump chamber 44 and a drive shaft chamber 52.

  A bush 61 that supports the drive shaft 13 is provided in the middle of the drive shaft through hole 60, and the upper portion of the drive shaft 13 is splined to the lower portion of the crankshaft 12 of the engine 10. Rotate together.

  In the middle of the drive shaft 13, a damper structure 70 that reduces the occurrence of abnormal noise due to torque fluctuations of the engine 10 is provided. The drive shaft 13 includes an upper drive shaft 13a, a lower drive shaft 13b, and a damper structure 70, and can be divided at a damper structure portion. The damper structure 70 includes an upper coupling 71, a lower coupling 72, a bush 73, a compression coil spring 74, and a torsion spring 75.

  The upper coupling 71 has a protrusion 71a and a fitting hole 71b at the lower part, and a spline hole 71c at the upper part. The lower coupling 72 has a fitting shaft 72a at the center, a flange 72b at the base of the fitting 72a, and a projection 72c formed on the flange 72b.

  A fitting shaft 72a of the lower coupling 72 is inserted into the fitting hole 71b of the upper coupling 71, and a compression coil spring 74 is inserted between the bottom of the fitting hole 71b and the tip of the fitting shaft 72a. Yes. A bush 73 is provided between the opening end inner peripheral surface 71b1 of the fitting hole 71b and the base outer peripheral surface 72a1 of the fitting shaft 72a. The torsion spring 75 is mounted in a mounting groove 72 d formed in the flange portion 72 b of the lower coupling 72. One end portion 75 a of the torsion spring 75 is engaged with an engaging portion 72 c 1 formed on the protruding portion 72 c of the lower coupling 72, and the other end portion 75 b is engaged with an engaging portion formed on the protruding portion 71 a of the upper coupling 71. It is locked to 71a1.

  The spline portion 13a1 of the upper drive shaft 13a is spline-fitted into the spline hole 71c of the upper coupling 71. Further, the spline portion 13b1 of the lower drive shaft 13b is spline-fitted into the spline hole 72e of the lower coupling 72. The upper coupling 71 and the lower coupling 72 are fitted so as to be rotatable.

  The compression coil spring 74 always urges the upper coupling 71 and the lower coupling 72 in the direction of separating them to ensure the spline engagement between the upper coupling 71 and the upper drive shaft 13a, and the lower coupling 72 and the lower drive shaft 13b. The spline is securely fitted. The bush 73 brings the upper coupling 71 and the lower coupling 72 into close contact with each other so that no rattling noise is generated between the upper coupling 71 and the lower coupling 72.

  The torsion spring 75 urges the abutment surfaces of the protrusion 71 a of the upper coupling 71 and the protrusion 72 c of the lower coupling 72 to be separated from each other, and the power between the upper coupling 71 and the lower coupling 72. Transmission takes place via a torsion spring 75.

  The output of the engine 10 is transmitted from the upper drive shaft 13a to the lower drive shaft 13b via the upper coupling 71, bush 73, torsion spring 75, and lower coupling 72, and further transmitted from the forward / reverse switching mechanism 14 to the propeller shaft 15. Is done. Therefore, during the low rotation of the engine 10, the rotational fluctuation of the engine 10 caused by irregular combustion of the engine 10 is reliably absorbed by the elastic torsional deformation of the torsion spring 75. When the output torque of the engine 10 gradually increases after passing through the low rotation range, the torsion spring 75 is torsionally deformed to a greater extent than described above, and the protrusion 71a of the upper coupling 71 abuts against the protrusion 72c of the lower coupling 72. It becomes possible. Thereby, a high output torque at the time of high rotation of the engine 10 is transmitted to the lower drive shaft 13b via the upper coupling 71, the bush 73, and the lower coupling 72.

  Therefore, even if a rotational fluctuation occurs when the engine 10 rotates at a low speed, the rotational fluctuation can be reliably absorbed by the elastic torsional deformation of the torsion spring 75, and the rotation of the propeller 16 can be smoothed. As a result, it is possible to prevent the propulsion unit 4 and the hull from generating vibrations and noises due to fluctuations in the propulsive force associated with fluctuations in the rotation of the propeller 16.

  In this embodiment, a water draining hole 80 communicating with the drive shaft through hole 60 is provided at a position above the bush 61 of the upper case 8, and water from the outside passes through the water draining hole 80 and the drive shaft through hole 60. The bush 61 is cooled. Further, water descends from a water drop passage 81 formed between the bush 61 and the upper case 8 to cool the damper structure 70.

  The damper structure 70 is provided between the mating surfaces 9 a and 8 a of the lower case 9 and the upper case 8 and the bush 61. That is, since the damper structure 70 is disposed below the bush 61, even if a damper structure having a diameter larger than that of the bush 61 is provided, it is only necessary to insert the drive shaft 13 and attach the lower case 9 as usual. The generation of noise due to torque fluctuation of 10 is reduced, and at the same time, the assembly work is not troublesome.

  The drive shaft 13 can be divided at the damper structure. Therefore, when the drive shaft 13 is assembled, the drive shaft 13 is divided, and the upper drive shaft 13a, which is one drive shaft, is first inserted into the upper case 8, and then the other drive shaft integrated with the lower case 9 is assembled. The lower drive shaft 13b is attached via the damper structure 70. Thus, by dividing and assembling the drive shaft 13 provided with the damper structure 70, the troublesomeness of inserting the long drive shaft 13 is reduced, and the assembly is facilitated.

  Further, since the damper structure 70 is disposed above the water pump 34 operated by the drive shaft 13, the space above the water pump 34 can be used effectively, and the damper is not required without significantly changing the conventional cooling water passage structure. A structure 70 can be installed.

  In addition, the damper structure 70 is disposed below the position of the lower mount portion 3b that supports the propulsion unit 4 provided on the upper case 8 on the steering shaft side. A conventional support member such as a steering shaft can be used.

  In the present invention, a damper structure is provided in the middle of the drive shaft to reduce the generation of abnormal noise due to engine torque fluctuations. The drive shaft has a diameter that increases only in the portion of the damper structure. Since the damper structure is provided below the bushing, it is only necessary to insert the drive shaft and install the lower case as usual. As well as reducing the generation of noise, the assembly work is not cumbersome.

FIG. 3 is a side view of an outboard motor mounted on the hull. It is a longitudinal cross-sectional view of an outboard motor. It is an enlarged view of the principal part of an outboard motor. It is a perspective view of a damper structure. It is a disassembled perspective view of a damper structure.

Explanation of symbols

1 Outboard Motor 7 Cowling 8 Upper Case 9 Lower Case 10 Engine 13 Drive Shaft 60 Drive Shaft Through Hole 61 Bush 70 Damper Structure

Claims (5)

A lower case in which the drive shaft is supported by a bearing and an upper case having a drive shaft through hole are provided as constituent members, and a bush for supporting the drive shaft is provided in the middle of the drive shaft through hole. In an outboard motor that is splined to the engine,
In the middle of the drive shaft, a damper structure that reduces the occurrence of abnormal noise due to torque fluctuations of the engine is provided,
The outboard motor, wherein the damper structure is provided between a mating surface of the lower case and the upper case and the bush.   2. The outboard motor according to claim 1, wherein a water intake hole communicating with the drive shaft through hole is provided at a position above the bush of the upper case.   The outboard motor according to claim 1, wherein the drive shaft is separable at a damper structure portion.   The outboard motor according to any one of claims 1 to 3, wherein the damper structure is disposed above a water pump operated by the drive shaft.   The damper structure according to any one of claims 1 to 4, wherein the damper structure is disposed below the position of a mount portion that is provided in the upper case and supports the propulsion unit on the steering shaft side. Outboard motor.

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