JP2661660B2 - Outboard motor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outboard motor having a four-cycle engine. 2. Description of the Related Art An outboard motor has a four-stroke engine housed in a main body supported on a hull by a bracket device having a support shaft and a swivel shaft so as to be vertically movable and left and right steerable. . It is known that an inertial force is generated in a four-cycle engine housed in an outboard motor due to reciprocation of a piston or the like, and the engine generates vibration or the like due to the inertial force. Therefore, a crank web is set on the crankshaft in order to cancel the inertial force of the piston or the like and to prevent engine vibration and the like.
However, since the crank web generates a new inertia force in the movement perpendicular to the piston movement direction and causes another vibration, the crank web rotates in the opposite direction at the same speed as the crankshaft, and the extra inertia force of the crank web is generated. A new balancer is needed to counteract. That is, in this balancer device, the inertia force of the piston is canceled in the direction of movement of the piston in cooperation with the crank web, and the inertia force of the crank web is canceled in the direction orthogonal to the movement of the piston. Things. As the above balancer device, Japanese Utility Model Publication No. 52-3
As shown in Japanese Patent Publication No. 2802, a crankshaft is generally provided with a pair of balancers on both radial sides of the crankshaft via gears or the like. [0004] However, depending on how the balancer is arranged on the engine or how the balancer is supported, the size of the engine and the device on which the engine is mounted are increased and the surroundings of the engine are complicated. This makes it difficult to mount other engine parts and engine accessories around the engine. SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to reduce the amount of protrusion protruding forward of an engine case, that is, toward a bracket device.
The purpose is to avoid interference with the body that houses the engine. Means for Solving the Problems The invention according to claim 1 is:
An outboard motor that accommodates a four-cycle engine in a main body supported on a hull so as to be able to move up and down and to be steerable left and right through a bracket device having a support shaft and a swivel shaft. At the top end,
And a camshaft drive pulley
Fly above the lee and with a ring gear on the outer circumference
Attach wheel and have separate axis from crankshaft
A pair of balancers are distributed to the left and right sides of the engine case with the crankshaft interposed therebetween, and the balancer shaft is arranged in parallel with the crankshaft, and meshes with the ring gear.
Drive gear that moves up and down with respect to this ring gear
The automatic starter having a, there is generally a side towards the engine case, and wherein by longitudinal and one of the balancer
Place and secure the automatic starter to the engine case
Characterized in that was. Either the balancer or the automatic starter as a whole can be prevented from protruding greatly toward the front of the engine case, and the amount of protrusion toward the front of the engine case, that is, the bracket device side, is small, and the engine is housed. Interference with the main body can be avoided. Conversely, if the engine case that satisfies the above conditions is prioritized, the engine does not need to move backwards extra, so the engine mount does not move backwards more than necessary and can be supported at a suitable position. It is. Also,
With a ring gear above the shaft pulley
With the flywheel, the automatic starter
Because it is slightly higher, the automatic starter and other
Interference with the structure can be avoided. A preferred embodiment of the present invention will be described in detail by taking an outboard motor as an example with reference to the accompanying drawings. FIG. 1 shows an overall view of an outboard motor attached to a small boat. Reference numeral 2 denotes a stern bracket attached to a stern of a hull via a clamp member 2a. Support. An intermediate portion of a support arm 5 is supported on a head 4a of a swivel shaft 4 rotatably supported in the swivel bracket 3, and an outboard motor main body is provided at one end of the support arm 5 via an engine mount 6. 1 is supported, and an operation handle 7 is attached to the other end of the support arm 5. The external structure of the outboard motor body 1 includes an engine cover 8, an engine 20 (see FIG. 2) and an oil case 9 for supporting an auxiliary machine, and a lower case 10 below which a propeller 11 and the like are mounted. The cases 9 and 10 are integrally connected by bolts and the like, and the lower case 1
The upper part of the outboard motor 0 is supported from both sides by extension mounts 12a of the arm member 12 extending from the swivel shaft 4 to prevent the outboard motor body 1 from touching sideways. FIG. 2 shows the construction of a four-stroke engine 20 for an outboard motor or an auxiliary machine supported in an oil case 9. The engine 20 is a two-cylinder four-stroke engine having a vertically supported crankshaft 24. The main part of the external appearance is formed with upper and lower cylinder parts 21a, 21a inside, and an engine case 21 having pistons 22, 22, connecting rods 23, 23, a crankshaft 24, etc., and attached to the engine case 21. And the camshaft 2
6, an engine head 25 having a rocker shaft 27, intake and exhaust valves 28,... Note that the engine case 21 is provided with the cylinder 2
1a, 21a, and a rear crankcase portion 21b wider than the cylinder portions 21a, 21a. The crankshaft 24 includes a central crank portion 24a, an upper shaft portion 24b, and a lower shaft portion 24c that partially protrude from the engine case 21. The crank portion 24a is generated by a reciprocating motion of the piston 22 or the like. Four crank webs 24a to cancel inertial force
1, ... (balance weights) are attached. Since the two pistons 22, 22 always move in the same direction, the four crank webs 24a-1,... Also move in the same direction in order to cancel the inertial force generated by the pistons 22, 22, etc. Become. The crankshaft 2 of the engine 20 described above
4 is connected to the propeller 11 via rotation transmitting means (not shown), and a camshaft drive pulley 29 and a flywheel 30 are attached to the upper shaft portion 24b, and are supported by the flyhole 30. A recoil starter 32 for manually starting the engine 20 is connected via a starter pulley 31. The balancer device 40 includes a drive gear 41,
The drive gear 41 of the balancer device 40 includes balancers 42, 42, a balancer case 43, a case cover 44, and the like, and is provided between the upper part 24 b of the crankshaft 24 between the upper part of the engine case 21 and the camshaft drive pulley 29. As shown in FIG. 3, the drive gear 41 is provided with two balancers 42, 42 whose phases are shifted from each other by approximately 180 degrees around the drive gear 41, via the gear portions 42c, 42c. Are in mesh. The arrangement direction of the balancers 42 and 42 around the crankshaft 24 is as follows.
It is inclined by a predetermined obtuse angle (θ) with respect to the axial direction of the cylinder portion 21a of the engine case 21 (the longitudinal direction of the engine 20). As shown in FIG. 4, the balancer 42 is parallel to a gear portion 42c formed on the radially outer periphery, a weight portion 42a having a thickness on one side in the radial direction, and the crankshaft 24. Since the gear diameter of the gear portion 42c is equal to the gear diameter of the drive gear 52, the gear portion 42c rotates in the opposite direction at the same rotational speed as the crankshaft 24, and the balancer shaft 42b The directions of the weight portions 42a, 42a are configured to be located in the same direction with respect to the rotation of the crankshaft 24. The balancer 42 has its balancer shaft 4
The lower portion of the balancer 2b is pivotally supported by a balancer case 43 formed to protrude from the engine case 21, and the upper portion of the balancer shaft 42b is pivotally supported by a case cover 44 of the balancer case 43. The case cover 44 supports the cover 32a of the recoil starter 32, as shown in FIG. The operation of the crank webs 24a-1,... And the balancer device 40 will now be described with reference to FIG.
Each of the four crank webs 24a-1,... Has a half of the inertial force due to the reciprocating mass of the crank system, and the weight portions 4 of the balancers 42, 42 of the balancer device 40.
2a and 42a each have a quarter of the inertial force due to the reciprocating mass.
1, and the weight portions 42a, 42 of the balancers 42, 42
a is configured so that the directions coincide at the top and bottom dead centers of the pistons 22, 22.
The inertial force generated by the reciprocating motion of the crankshaft 22 becomes zero by the cooperation of the crank webs 24a-1,... And the balancer device 40, and the movement of the pistons 22, 22 by the crank webs 24a-1,. The inertial force in the direction perpendicular to the direction is also zero because the rotation directions are opposite to each other, and the vibration of the engine 20 is effectively suppressed. Since the plane of action of the inertial force between the balancer device 40 and the crank webs 24a-1,... Is divided above and below the crankshaft 24, the crankshaft 24 is rotated vertically. The corner force acts, and this corner force is applied to the entire outboard motor body 1 via the oil case 9, but the outboard motor body 1 shown in FIG. 1 is provided with the engine mount 6 and the extension mount 12a. The corner force is absorbed and canceled by these mounts 6 and 12a because it is supported by the swivel bracket 3 at the top and bottom. Since the balancer case 43 and the like of the balancer device 40 are provided separately from the engine 20 above the engine case 21, the width of the engine 20 itself can be reduced, and the size of the engine 20 can be reduced. Since the balancer case 43 and the like are disposed obliquely across the engine 20, the width of the outboard motor body 1 in which these are disposed can be suppressed as small as possible. As shown in FIG. 5, the portion of the balancer case 43 or the like protruding toward the rear side of the engine, ie, toward the crankcase portion 21b of the engine case 21, and the cylinder portion 21b of the engine case 21 form an obtuse angle θ. Because they intersect, the engine case 21 and the balancer case 4
An obtuse wall W is formed in a portion surrounded by 3 and the like, and a wide space S1 is formed around the obtuse wall W along the crankshaft 24 in the vertical direction. As shown in FIGS. 4 and 5, the front side of the engine, such as the balancer case 43, protrudes from the engine case 21 and the engine case 21 and the balancer case 43 define a recess V (fourth). Accordingly, a long front-rear space S2 is formed along the engine case 21 in the front-rear direction of the engine 20. In the wide space S1, engine parts or engine accessories can be conveniently disposed in close contact with the engine 20. In this embodiment, as shown in FIGS. Starter 50 is provided. The starter 50 has a main body support 51,
51 is attached to the engine case 21 by bolts or the like, and the upper drive gear 52 of the starter 50 meshes with the ring gear 30a attached to the flywheel 30 to start the engine 20. When not in use, as shown in FIG. 4, the drive gear 52 moves below the ring gear 30a so that they do not interfere with each other. The flywheel 30 includes a balancer device 40
, The starter 50 and the driving gear 52 have a favorable meshing positional relationship. That is, since the drive gear 52 of the starter 50 moves up and down, the ring gear 30a of the flywheel 30 should be located as high as possible. Further, since the starter 50 is mounted on the upper part of the engine case 21, the drive gear 52
This is because the position 2 is naturally disposed above. The balancer device 40 includes a crankshaft 2
4 is closer to the crank web 24a-1, ...
The upper and lower corner forces generated in the crankshaft 24 can be reduced, which is preferable. Also, as shown in FIGS. 3 to 5, engine parts or engine accessories can be conveniently disposed in the front-rear space S2 below the balancer device 40 in close contact with the engine 20. In the present embodiment, the carburetor 60 and the like are disposed using a long space before and after the carburetor. That is, the outboard motor is mounted in an engine cover (main body) 8 supported on the hull via a swivel bracket (bracket device) 3 having a support shaft 3a and a swivel shaft 4 so as to be vertically movable and left and right steerable. An outboard motor accommodating a four-cycle engine 20, in which a crankshaft 24 is disposed vertically and a pair of balancers 4
2 and 42 are distributed to the left and right sides of the engine case 21 with the crankshaft 24 therebetween, and the balancer shafts 42b and 4
The starter (automatic starter) 50 is arranged in parallel with the crankshaft 24, substantially on the side of the engine case 21, and in front of and behind one of the balancers 42. The carburetor 60 includes an engine head 25
The carburetor 60 is provided with an air inlet pipe 62 attached thereto via an intake manifold 61, and is long and arranged in parallel with the engine as a whole. In this case, the intake manifold 61 preferably has a somewhat longer pipe length in order to improve the mixing of the mixture of fuel oil and air and to evenly distribute the mixture to the two cylinder portions 21a, 21a. Also,
It is preferable that the air inflow pipe 62 be somewhat long in order to enhance the rectification effect of air entering the carburetor 60. Therefore, the front and rear space S2 which is long in the front and rear direction along the engine 20 is most effectively used in this case. Further, by arranging the carburetor 60 and the like in the front and rear space S2, the outboard motor main body 1 can be made small and compact. Further, the balancer device 40
In this embodiment, which is intended for an outboard motor, the balancers 42, 42 are arranged on substantially the same plane with the crankshaft 24 interposed therebetween. However, in the general crankshaft vertical support type engine 20, one of the 24, the wide space S1 and the front and rear space S2 as described above are sufficiently ensured even if the upper shaft portion 24b and the other are shifted to the lower shaft portion 24c and disposed outside the engine case 21. Can be sufficiently reduced in size. In this case, the crank webs 24a-1,.
Are arranged so as to sandwich the upper and lower sides of the crankshaft 24, no corner force is generated which causes the crankshaft 24 to rotate up and down due to the inertial force of the crank web balancer. Further, in the present embodiment, a description has been given by taking as an example a two-cylinder four-stroke engine in which the crankshaft 24 is supported vertically, but the invention is not limited to this.
May be supported horizontally, and the number of cylinders and the number of cycles of the engine 20 may be changed. Further, in the present embodiment, the balancers 42, 42 are disposed on the upper left of FIG. 3, but the present invention is not limited to this, and the front and rear space S2 is ensured even if the balancers 42, 42 are disposed on the upper right. No matter what you can do. In this case, the upper and lower wide spaces S1 are slightly narrowed. According to the present invention, the following effects can be obtained by the above-mentioned structure. The invention according to claim 1 is an outboard motor that accommodates a four-cycle engine in a main body supported on a hull so as to be vertically movable and left and right steerable via a bracket device having a support shaft and a swivel shaft, Vertically placed
At the upper end of the rank shaft, a camshaft drive pulley
And above and outside of this camshaft drive pulley.
Attach a flywheel with a ring gear around
The crankshafts left engine case a pair of balancer between a crank shaft having a different axis, are distributed to the right side, placing the axis of the balancer in parallel with the crank shaft, meshing with the ring gear, the ring gear
Automatic starter with a drive gear that moves up and down
, Said a is generally the side towards the engine case, and arranged the by longitudinal and one of the balancer, automatic starter
By fixing the balancer and the automatic starter to the engine case, it is possible to prevent the whole of the balancer and the automatic starter from protruding greatly toward the front of the engine case. The amount is small, and interference with the body housing the engine can be avoided. Conversely, if the engine case that satisfies the above conditions is prioritized, the engine does not need to move backwards extra, so the engine mount does not move backwards more than necessary and can be supported at a suitable position. It is. Also, above the camshaft drive pulley
With a flywheel equipped with a ring gear
Since the automatic starter is slightly higher,
To avoid interference between the unit and other structures below it.
Wear.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing an entire outboard motor according to the present invention. FIG. 2 is a cross-sectional side view around a 4-cycle engine for an outboard motor according to the present invention and the engine. FIG. 4 is a cross-sectional view of a four-stroke engine and a carburetor for an outboard motor according to the present invention. FIG. 4 is a cross-sectional view of a balancer device according to the present invention. FIG. [FIG. 6] Side view of FIG. 5 [Description of reference numerals] 1 ... Outboard motor main body, 3 ... Bracket device (swivel bracket), 3a ... Support shaft, 4 ... Swivel shaft, 20 ... Outboard motor 4 Cycle engine, 21 ... engine case, 2
1a ... cylinder part, 24 ... crankshaft, 24b ...
Upper shaft part of the crankshaft, 24c lower shaft part of the crankshaft, 30a ring gear, 41 drive gear, 42 balancer, 42a weight part, 42b
... balancer shaft, 42c ... gear part, 43 ... balancer case, 50 ... automatic starter (starter), S1 ... wide space, S2 ... front and rear space, V ... concave part, W ... obtuse angle wall part.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location F16F 15/26 B63H 21/26 Z

Claims (1)

(57) [Claims] An outboard motor that accommodates a four-cycle engine in a main body supported on a hull so as to be able to move up and down and to be steerable left and right through a bracket device having a support shaft and a swivel shaft. At the top end,
Shaft drive pulley and this camshaft drive pulley
Fly hoist with a ring gear on the upper side and above
Mounting a Lumpur, the left engine case a pair of balancer between a crank shaft having a shaft different from the crankshaft, and distributed to the right side, placing the axis of the balancer in parallel with the crankshaft, wherein Meshes with the ring gear, and
An automatic starter having a drive gear that moves downward and forward is disposed substantially in the side of the engine case, in front of and behind one of the balancers, and the automatic starter is fixed to the engine case. />.