JPS5839863A - Balancer of engine - Google Patents

Abstract

PURPOSE:To obtain a small-size and light weight engine by providing the first balancer negative the primary inertial force on the main shaft of a speed change gear arranged in parallel with a crank shaft and the second balancer negating the inertial couple around the crank sgaft on an auxiliary shaft. CONSTITUTION:The main shaft 40 and auxiliary shaft 42 of a normally engaged type speed change gear 38 are arranged in parallel with a crank shaft 10, and the first balancer 54 provided with a sprocket 56 fixed in one body is rotatably held on the main shaft 40, and the second balancer 58 provided with a sprocket 60 fixed in one body on the auxiliary shaft 42 respectively. A chain 64 is suspended across the sprockets 56, 60 and the sprocket 36 of the crank shaft 10, thereby the first balancer 54 is driven to rotate at the same speed as and in the opposite direction to the crank shaft 10 and the second balancer 58 at the same speed as and in the same direction to said crank shaft 10 respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a balancer device that cancels the primary inertial force and inertial couple of an engine and reduces engine vibration.

A single-cylinder engine or a parallel two-cylinder engine with an in-phase crankshaft is equipped with two balancers that rotate at the same speed as the crankshaft and in opposite directions, and these balancers cancel out the primary inertial force and the inertial couple. There has always been something that has been done. However, in conventional systems, these two balancers are arranged so that the crankshaft is located between them, while the shafts that hold each balancer are independent without being shared with the shafts of other transmissions, etc. This had the disadvantage of increasing the size and weight of the engine.

Furthermore, since these balancers rotate at high speeds at the same speed as the crankshaft, their bearings must also be of high precision that can withstand high speed rotation, which has the disadvantage of reducing the durability of these bearings.

The present invention was made in view of these disadvantages, and an object of the present invention is to provide an engine balancer device that is suitable for downsizing and increasing the number of engines, and can significantly improve the durability of the balancer bearings. It is something.

In order to achieve such an object, the present invention provides an engine in which a main shaft and a subshaft of a transmission are disposed parallel to a crankshaft, and these main shaft and subshaft rotate in the opposite direction and the same direction as the crankshaft, respectively. The main shaft has a first balancer that is rotationally driven in the opposite direction at the same speed as the crankshaft, and the subshaft has a second balancer that is rotationally driven in the same direction at the same speed as the crankshaft. The first balancer mainly cancels the primary inertia force, and the second balancer mainly cancels the inertia couple around the crankshaft. The present invention will be explained in detail below with reference to examples shown in the accompanying drawings.

FIG. 1 is a plan cross-sectional view of one embodiment of the present invention, and FIG. 2 is a side cross-sectional view of the same essential parts. This embodiment is a four-stroke parallel two-cylinder engine used in a motorcycle, and is equipped with an in-phase crankshaft 10. In other words, each cylinder is connected to the crankshaft 1
Explosions alternately and at equal intervals every rotation of 0. This crankshaft 10 has an upper crankcase 12 and a lower crankcase 14.
A gear 16 is fixed to one shaft end of the shaft. 18 is the cylinder body, 2
0 (20A, 20B) is the piston of each cylinder, 22 (22
A, 22B) are the connecting rods of each cylinder, and 24 (24
A, 24B) are the crank webs of each cylinder. 26 is a sprocket formed at the center of the crankshaft 10, and an overhead camshaft (not shown) is driven by a timing chain 28 that is wound around the sprocket 26.

30 is the cylinder head, and in Fig. 2, 32 is the intake valve;
Reference numeral 4 denotes an exhaust valve, and these intake and exhaust valves 32 and 34 are opened and closed by a known valve mechanism including an overhead camshaft.

Further, 36 is a sprocket formed on the crankshaft 10 so as to be adjacent to the sprocket 26, and this sprocket 36 drives balancers 54 and 58, which will be described later.

In the first factor, 38 is a constant-mesh type transmission, and its main shaft 40 and counter shaft 42 are disposed parallel to the crankshaft 10. The main shaft 40 is connected to the upper and lower crankcases 12.14.
The subshaft 42 is held by bearings 44 and 46 between the table surfaces of the subshaft 42, and the subshaft 42 is held by bearings 48 and 50 in the left-right split upper crankcase 12.

A gear group 52 is held on the main shaft 40 and the counter shaft 42, and the gears are changed by changing the connection between the gear group 52 and the main and counter shafts 40°42.

A first balancer 54 is rotatably held on the main shaft 40 adjacent to the transmission gear group 52, and a sprocket 56 is integrally fixed to the first balance t54. A second balancer 58 is rotatably held on the subshaft 42 adjacent to the transmission gear group 52, and a sprocket 60 is integrally fixed to the second balancer 58. That is, the first balancer 54 is attached to the main shaft 40 via the collar 62, and the second balancer 58 is attached directly to the subshaft 42, and the inner circumferential surfaces of the first and second balancers 54 and 58 serve as sliding surfaces. ing. These first
1. The sprocket 56.60 of the second balancer 54.58 and the sprocket 36 of the crankshaft 10 have a second
As shown in the figure, a chain 64 is wound around the first balancer 54, and the first balancer 54 is driven to rotate in the opposite direction at the same speed as the crankshaft 10.
Further, the second balancer 58 is driven to rotate at the same speed and in the same direction as the crankshaft 1o. As mentioned above, the rank shaft 1o and the main shaft 4° are held between the surfaces of the upper crankcase 12 and the lower crankcase 14, and the countershaft 42 is held by the upper crankcase 12, so that the chain 64 The outbound and return routes do not interfere with each other. The weight portion of the first balancer 54 is located in substantially the same direction as the crank web 24 at the top dead center position or the bottom dead center position of the piston 2o, and the weight portion of the second balancer 58 is located at the top dead center position or the bottom dead center position of the piston 2o. The weight portion of the 1 balancer 54 is positioned so as to rotate upward when the weight portion rotates downward. The total mass of the first balancer 54 and the crank web 24 is approximately equal to the mass of the reciprocating portion of the piston 20 and connecting rod 22, and the mass of the second balancer 58 is determined to cancel the inertial couple caused by the first balancer 54. ing.

In FIG. 1, reference numeral 66 denotes a known wet type multi-disc clutch, which is mounted on the right shaft end of the main shaft 40. The rotation of the crankshaft 10 is controlled by the gear 16 and the reduction gear 68.
The signal is transmitted to the clutch 66 through the transmission, and further transmitted to the main shaft 4o of the transmission 38. In FIG. 1, 70 is a sprocket fixed to the left end of the subshaft 42, and the output of this engine is transmitted to the rear wheels (not verbally) via a chain 72 that is wound around this sprocket 70.

Next, the operation of this embodiment will be explained. If the crankshaft 10 now rotates clockwise as shown by the arrow in FIG.
The balancer 54 moves counterclockwise, and the second balancer 58 moves clockwise. The inertial force of the reciprocating parts such as the piston 20 and the connecting rod 22 in the direction of movement is canceled by the crank web 24 and the first balancer 54, and the inertial force of the crank web 24 in the direction perpendicular to the direction of movement of the piston 20 is canceled by the crank web 24 and the first balancer 54. This is canceled out by the first balancer 54 that rotates in the opposite direction to the shaft 1o. As a result, the primary inertial force can be almost completely canceled.

The first balancer 54 rotates in the direction I around the crankshaft 10.
: An inertial couple is generated, but this inertial couple is canceled by the second balancer 58. Note that due to the rotation of the second balancer 58, an inertial force is generated in a direction perpendicular to the movement direction of the piston 20, but the influence of this inertial force is due to the mass of the first and second balancers 54, 58 and the crank web 24. By appropriately selecting the distribution and phase, the brightness can be reduced to a negligible level.As a result, the primary inertial force and the inertial couple are canceled by the first and second balancers 54 and 58,
Engine vibration can be significantly reduced.

On the other hand, the rotation of the crankshaft 10 is controlled by the gear 16 and the large reduction gear 6.
8. Transmitted to the main shaft 40 via the clutch 66,
0 rotates in the opposite direction C- to the crankshaft lO. That is, the main shaft 40 first rotates in the same direction as the lancer 54. Further, the subshaft 42 rotates in the opposite direction to the main shaft 40 via the transmission gear group 52, that is, in the same direction as the second lancer 58.

In this way (1), since the first and second balancers 54 and 58' rotate in the same direction as the rotational direction of the main shaft 40 and the subshaft 42, respectively, the first and second balancers 54 and 58 and the main shaft that holds them rotate. The relative rotational speed with the countershaft 40, 42 is reduced, and the durability of the bearing portions of these balancers 54, 58 is improved.

In this embodiment, each balancer 54, 58 is connected to a chain 6.
4. However, it goes without saying that these may be driven by gears.

As described above, the present invention provides the first and second balancers that are rotated at the same speed as the crankshaft in the opposite direction and the same direction, and the first balancer and the crank web mainly cancel the primary inertia force. On the other hand, since the second balancer mainly cancels out the inertia couple around the crankshaft generated by the first balancer, engine vibration can be significantly reduced. Furthermore, since these first and second balancers are held on the main shaft and subshaft of the transmission, respectively, there is no need to provide an independent shaft for holding the balancers, which is suitable for reducing the size and weight of the engine. Furthermore, since the main shaft and the subshaft rotate in the opposite direction and the same direction as the crankshaft, the relative rotational speeds between the first and second balancers and the main shaft and the subshaft become small.

Therefore, the durability of the bearings of these balancers is improved, and in other words, it is no longer necessary to use high-precision bearings for high speeds.

[Brief explanation of drawings]

FIG. 1 is a half sectional view showing an embodiment of the present invention, and FIG. 2 is a partially omitted side sectional view. lO...crankshaft, 24...crank web, 3
8... Transmission, 54... First balancer, 58...
2nd Baran Homare.

Claims (1)

[Claims] In an engine in which a main shaft and a subshaft of a transmission are disposed parallel to a crankshaft, and the main shaft and subshaft rotate in the opposite direction and the same direction as the crankshaft, respectively, the main shaft has a main shaft and a subshaft that rotate at the same speed and in the opposite direction as the crankshaft. The first rotationally driven
A balancer is held on the subshaft, and a second balance is held on the subshaft, and is driven to rotate at the same speed and in the same direction as the crankshaft.
1. A balancer device for an engine, characterized in that the second balancer cancels the second inertial force and mainly cancels the inertia couple around the crankshaft.