JPH08230786A - Outboard motor - Google Patents

Abstract

PURPOSE: To improve the damping effect by a mount by providing a balancer device of an engine where two rotary shafts parallel to a crankshaft are symmetrically arranged in the right-to-left direction above the mount and below a flywheel. CONSTITUTION: A balancer device 40 consists of a drive gear 41, balancers 42, 42, a balancer case 43 and a case cover 44, and the drive gear 41 is mounted on an upper shaft 24c of a crankshaft 24 between the upper part of an engine case 21 and a cam shaft drive pulley 29. The balancer device 40 where two rotary shafts 42b, 42b parallel to the crankshaft 24 are symmetrically arranged in the right-to-left direction is provided above the mount (an engine mount 6 and an extension mount) and below a flywheel. An unbalanced part is brought close to not only a cylinder part but also the mount to improve the damping effect by the mount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outboard motor provided with an engine balancer device.

[0002]

2. Description of the Related Art There are known outboard motors that are swingably attached to the stern of a small boat and have an engine and a propulsion mechanism. Due to its function, the engine of this outboard motor is often a vertical support type in which the cylinders are arranged horizontally and the crankshaft is arranged vertically. Further, the engine is provided with a crank web for balancing the inertial force on the crank shaft in order to suppress engine vibration and the like due to the reciprocating movement of the piston. However, the crank web generates a new inertial force in the direction orthogonal to the piston movement direction, and causes another vibration.Therefore, the crank web rotates at the same speed as the crank shaft in the opposite direction, and the extra inertial force of the crank web is generated. A new balancer device to cancel is needed. That is, this balancer device cancels the inertial force of the piston in the direction of movement of the piston in cooperation with the crank web and cancels the inertial force of the crank web in the direction orthogonal to the movement of the piston. is there.

[0003]

The balancer device described above is disclosed in Japanese Utility Model Publication No. 52-32802.
It is known that a pair of balancers are provided on both sides of the crankshaft in the radial direction of the crankshaft via gears, but an engine of a type in which the crankshaft is vertically supported like an outboard motor is mounted and In the case where the mount is used for anti-vibration, its mounting structure becomes a problem.

The present invention has been made to solve the above problems, and an object of the present invention is to mount an engine having a balancer so as not to lower the vibration isolation effect of the mount as much as possible. To provide.
Another object is to provide an outboard motor that is compact and compact.

[0005]

According to a first aspect of the present invention for achieving the above object, a pair of mounts are arranged on the left and right of upper and lower parts in a swivel bracket pivotally supported by a stern bracket. In the outboard motor, in which the outboard motor main body is supported via the crankshaft and the crankshaft is placed in a substantially vertical position, and an engine having a flywheel attached to the upper portion thereof is mounted on a support portion of the outboard motor main body, A balancer device for the engine, in which two rotary shafts parallel to the crankshaft are distributed in the left-right direction, is provided above the mount and below the flywheel. The unbalanced part is closer to the cylinder and closer to the mount, so that the mount has a greater vibration isolation effect than the one that provides an unbalanced amount on the flywheel. Since the mount and the balancer device do not interfere with each other, the outboard motor can be made compact.

The invention according to claim 2 is characterized in that the supporting portion is located below the mount. Since the balancer device and the mount are close to each other, it is possible to reduce the influence on the reduction of the vibration isolation effect of the mount.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention are shown in FIGS.
This will be described below with reference to FIG. FIG. 1 is an overall view of the outboard motor. A stern bracket 2 is attached to the stern of the hull via a clamp member 2a, and pivotally supports the swivel bracket 3 via a support shaft 3a. A swivel shaft 4 is rotatably inserted into the swivel bracket 3, and a head 4a of the swivel shaft 4 supported by the upper end of the swivel bracket 3 has a support arm having two arms 5a, 5a. The middle part of 5 is supported. The outboard motor body 1 is supported by the tip ends of the arm portions 5a, 5a of the support arm 5 via the engine mounts 6, 6 and the operation handle 7 is attached to the other end of the support arm 5. .

The outer structure of the outboard motor body 1 includes an engine cover 11, an oil case 12 for supporting the engine 20 and accessories, and an extension case 13 below the oil case 12.
And a propeller 15 are attached to the gear case 14 and the like, and the cases 12, 13 and 14 are integrally connected by bolts or the like. Also, the swivel bracket 3
As shown in FIG. 3, two arm members 8, 8 arranged in a U-shape are attached to the lower part of the swivel shaft 4 protruding from the lower end of the vibration absorber 4 attached to the inside thereof. The extension mounts 9 and 9 made of members are the recesses 13 of the extension case 13 of the outboard motor body 1.
By sandwiching a and 13a, the lower part of the outboard motor body 1 is prevented from swinging and the vibration is absorbed.

Further, the oil case 12 has a bowl-like shape, and as shown in FIG.
a is formed, and the engine mounts 6, 6 are attached to the lower surfaces on both sides thereof. The engine mount 6 is shown in FIG.
As shown in FIG. 3, a vibration absorbing member 6b made of rubber or the like is fitted in the body 6a, and the arm portion 5a of the supporting arm 5 is connected to the vibration absorbing member 6b via a cylindrical collar 6c which is crimped. ing. Therefore, even if the oil case 12 vibrates due to the engine 20 or the like, the vibration is not transmitted to the swivel bracket 3 or the operation handle 7.

Next, the engine 20, the balancer device 40, etc. supported by the oil case 12 will be described. As shown in FIG. 4, the engine 20 is of a two-cylinder four-cycle type of vertically supporting a crankshaft, and the main part of its appearance has upper and lower cylinder parts 21a, 21a formed therein, and pistons 22, 22, connecting rods 23, 23, a crankshaft 24, etc., an engine case 21, a camshaft 27 attached to the engine case 21,
An engine head 26 having a rocker shaft 28, an intake / exhaust valve 25, ..., And the like, and the engine case 21 is the engine support portion 1 of the oil case 12.
2a. Further, the crankshaft 24 has crank webs 24a, 24a (balance weights) for canceling out inertial force generated by the piston 22 and the like.
Are mounted, and the two pistons 22, 22 always move in the same direction, the four crank webs 2
4a, ... Also all move in the same direction.

The crankshaft 2 of the engine 20 described above
The lower shaft 24b of No. 4 is connected to the propeller 15 via a rotation transmission means (not shown), and the upper shaft 24c thereof is
Camshaft drive pulley 29, fly hole 30
Is attached, and a recoil starter 32 for manually starting the engine 20 is connected via a starter pulley 31 supported by the flyhole 30.

The balancer device 40 includes a drive gear 41, balancers 42, 42, a balancer case 43, and a case cover 4.
The crankshaft 24 between the upper part of the engine case 21 and the camshaft drive pulley 29.
A drive gear 41 of the balancer device 40 is attached to the upper shaft 24c of the drive gear 41, and a predetermined angle θ (this angle θ
Is smaller than 00 degrees in order to reduce the width of the outboard motor body 1. ) As shown in FIG. 6, the balancers 42, 42 are in mesh with each other through the gear portions 42c, 42c in the inclined position.

The balancer 42 has the gear portion 42c formed on the outer periphery in the radial direction, the weight portion 42a having a thick wall on one side in the radial direction, and the balancer shaft 42b (which is arranged parallel to the crankshaft 24). Rotation shaft) and the like, and the gear diameter of the gear portion 42c is the drive gear 41
Since the gear diameter is equal to that of the crankshaft 24, the crankshaft 24 rotates at the same number of revolutions in the opposite direction, and the weight portions 42a, 42a of the balancers 42, 42 are always oriented in the same direction with respect to the rotation of the crankshaft 24. Is configured to.

Further, the balancer 42 is the balancer shaft 42.
The lower part of b is pivotally supported by the balancer case 43 formed by projecting from the engine case 21, and the upper part of the balancer shaft 42b is the case cover 4 of the balancer case 43.
It is pivotally supported by 4. The recoil starter 3
The second cover 32 a is supported by the case cover 44.

That is, since the balancers 42, 42 are covered and supported by the balancer case 43, which is a part of the engine case 21, and the case cover 44, a special support device or case is separately provided for the balancers 42, 42. No cover is required, and the balancer device 40 is small and compact. Further, the balancer device 40 is arranged above the engine case 21 obliquely with respect to the moving direction of the piston 22 of the engine 20 (longitudinal direction of the engine 20) and has a small protrusion amount to the side of the engine 20. The width of the outboard motor body 1 can also be kept small. Therefore, the outboard motor body 1 can be combined with the downsizing of the balancer device 40.
The compactness and compactness of is effectively achieved.

The operation of the crank webs 24a, ... And the balancer device 40 will be described below. Here, the four crank webs 24a, ... Have a half of the inertial force due to the reciprocating mass of the crank system, and the weight portions 42a, 42 of the balancers 42, 42 of the balancer device 40.
It is assumed that a has a quarter of the inertial force due to the reciprocating mass, and the crank webs 24a, ... And the balancer weight portions 42a, 42a are pistons 22, 22.
It is assumed that the directions are aligned at the top and bottom dead centers of.

In the above, the inertial force generated by the reciprocating motion of the pistons 22, 22 is the crank web 24.
, and the balancer weight section 42 of the balancer device 40.
a, 42a, and the crank web 24a,
... and the inertial forces of the balancer weight portions 42a, 42a in the directions orthogonal to the moving directions of the pistons 22, 22 become zero because their rotating directions are opposite to each other, and the vibration of the engine 20 is effectively suppressed.

However, the balancer weight portion 42
The acting surfaces of the inertial forces of a and 42a are the crankshaft 24
, And the acting surface of the inertial force of the crank webs 24a, ... Is the middle portion of the crankshaft 24, and these acting surfaces do not match, so that the crankshaft 2
At 4, a corner force is generated around a predetermined position in the longitudinal direction. This corner force is transmitted from the oil case 12 to which the engine 20 is attached to the outboard motor body 1 to vibrate the entire outboard motor body 1 and to rotate it vertically.

However, the connection between the swivel bracket 3 on the hull side and the outboard motor body 1 is such that the upper part thereof is via the engine mounts 6 and 6 and the lower part thereof is via the extension mounts 9, 9. The vibration absorbing action makes it difficult to transmit the vibration of the outboard motor body 1 to the swivel bracket 3, the hull, the driver, and the like. Further, since the outboard motor body 1 is supported by the upper engine mounts 6 and 6 and the lower extension mounts 9 and 9,
Assuming that the swivel bracket 3 is fixed to some extent, the vertical rotation of the outboard motor body 1 can be effectively suppressed.

Further, the balancer shafts (rotating shafts) 42b, 42
Since b is provided so as to be laterally distributed around the crankshaft 24, the amount of overhang to the front of the outboard motor is correspondingly smaller than that in the case where at least one balancer is provided on the cylinder axis. You can prevent it from affecting your exercise. Furthermore, the balancer device 40 of the engine 20 in which the two balancer shafts 42b, 42b parallel to the crankshaft 24 are laterally distributed is provided above the mount (engine mount 6 and extension mount 9) and below the flywheel 30. As a result, the unbalanced portion becomes closer to the cylinder portions (cylinders) 21a, ... And closer to the mount, so that the vibration damping effect of the mount is enhanced as compared with the case where an unbalanced amount is provided on the flywheel 30. Moreover, since the mount and the balancer device 40 do not interfere with each other, the outboard motor can be made compact. Further, the support portion 12
Since a is below the mount, the balancer device 40 and the mount are close to each other, and it is possible to reduce the influence on the reduction of the vibration isolation effect of the mount.

In the above-described embodiment of the present invention, the two-cylinder, four-cycle engine has been described, but the present invention is not limited to this, and it is of course any type of engine in which the crankshaft is arranged vertically. Is.

[0022]

The present invention has the following effects due to the above configuration. According to a first aspect of the present invention, the outboard motor main body is supported by mounts arranged in pairs on the left and right of the upper and lower parts of the swivel bracket pivotally supported by the stern bracket, and the crankshaft is placed substantially vertically. In the state,
An engine with a flywheel mounted on top of it is mounted on a support part of the outboard motor body. In an outboard motor, a balancer device for the engine, in which two rotary shafts parallel to the crankshaft are distributed in the left and right directions, is located above the mount. In addition, since the unbalanced portion is closer to the cylinder and closer to the mount because it is provided below the flywheel, the vibration isolation effect of the mount is enhanced as compared with the case where the unbalanced amount is provided on the flywheel. Moreover, since the mount and the balancer device do not interfere with each other, the outboard motor can be made compact.

According to the second aspect of the present invention, since the support portion is below the mount, the balancer device and the mount are close to each other, and it is possible to reduce the influence on the reduction of the vibration isolation effect of the mount.

[Brief description of drawings]

FIG. 1 is an overall view of an outboard motor according to the present invention.

FIG. 2 is a plan view of an oil case according to the present invention.

FIG. 3 is a sectional view showing an extension mount portion according to the present invention.

FIG. 4 is a sectional view of an engine and the like according to the present invention.

FIG. 5 is a diagram showing a mounted state of a balancer device and an engine according to the present invention.

FIG. 6 is a plan view of an engine or the like according to the present invention as seen from above.

[Explanation of symbols]

1 ... Outboard motor body, 2 ... Stern bracket, 3 ... Swivel bracket, 3a ... Shaft, 6 ... Mount (engine mount), 9 ... Mount (extension mount), 20 ... Engine, 21 ... Engine case, 24 ...
Crank shaft, 24a ... Crank web, 30 ... Flywheel, 40 ... Balancer device, 41 ... Drive gear,
42 ... Balancer, 42a ... Weight part, 42b ... Rotating shaft (balancer shaft), 42c ... Gear part, 43 ... Balancer case, 44 ... Case cover.

Claims (2)

[Claims] 1. A state in which the outboard motor main body is supported via mounts arranged in pairs on the left and right of the upper and lower parts of a swivel bracket pivotally supported by a stern bracket, and the crankshaft is placed substantially vertically. In an outboard motor in which a flywheel is mounted on the upper portion of the engine on a support portion of the outboard motor body, a balancer of the engine in which two rotary shafts parallel to the crankshaft are horizontally distributed An outboard motor, wherein the device is provided above the mount and below the flywheel. 2. The outboard motor according to claim 1, wherein the support portion is below the mount.