JPS6111426A - V-type engine - Google Patents

Abstract

PURPOSE:To reduce an overhang extent in a crankshaft as well as to prevent axial deflection from occurring, by supporting a generator pivotally on one end of the crankshaft, while installing a variable flywheel in an end part at the opposite side through bearings. CONSTITUTION:Connecting rods 9 and 10 of two cylinders being set up in a V- type form are paralleled in line on a crankpin 8 and pivotally joined together. A generator 14 is pivotally supported on the left end of a crankshaft 1. A variable flywheel unit 19 is installed in an end part at the opposite side through bearings. A primary drive gear 11 is pivotally supported on the outer side end, transmitting power to a transmission gear mechanism. Thus, the generator and the variable flywheel are made possible to be set up in a good balancing manner so that an overhang extent of the crankshaft is reducible and axial deflection in the crankshaft is preventable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a V-type engine equipped with a variable flywheel to increase the moment of inertia in a low speed rotation range.

[Technical background of the invention]

In a four-stroke V-type engine, the connecting rods of cylinders on both sides of one crank pin are often aligned in parallel. In such a one-pin transmission type, if the design focuses on weight reduction, the moment of inertia of the crank system will be reduced. For this reason, the moment of inertia of the generator etc. installed on the crankshaft is increased to ensure the absolute moment of inertia of the entire crank system while suppressing weight increase. However, a certain amount of moment of inertia is required in low rotation ranges such as idling and slow speed, and it is better to have a small moment of inertia during rotation and sudden acceleration. Therefore, a variable flywheel is used to adapt to the low-speed and fast-speed rotation ranges. This variable flywheel has an appropriate mass and rotates together with the crankshaft in the low rotation range, and is separated from the crankshaft by centrifugal force when the engine enters the high speed range, thus satisfying the above requirements.

[Problems with background technology]

When equipped with the above variable flywheel, the crankshaft has
The generator, the sprocket wheel for the valve train, the primary drive gear for power transmission, and this variable flywheel are mounted on the shaft, which places a severe burden on the shaft. Since these members are supported on the overhang part outside of the bearing member, the amount of overhang increases.
The balance becomes unstable and there is a high risk of inducing shaft runout.

[Purpose of the invention]

The purpose of this invention is to take the above-mentioned problems into account and arrange the generator and variable flywheel in a well-balanced manner together with other parts to reduce the amount of overhang of the crankshaft and to prevent shaft runout. The aim is to provide a V-type engine.

[Summary of the invention]

In order to achieve the above object, the V-type engine of the present invention is generally configured as follows. In other words, in a V-type engine in which the connecting rods of both cylinders arranged 7 m apart are aligned in parallel to one crank pin, the generator is supported by a metal shaft at one end of the crankshaft, and a variable flywheel is mounted at the opposite end. A primary drive gear is pivotally supported at the outer end to transmit power to the transmission gear mechanism.

With the above configuration, the moment of inertia on the crankshaft is well balanced, the amount of overhang at both ends is minimized, and shaft runout is prevented. In particular, in a V-type engine with one crank pin and two connecting rods, both cylinders are offset, so the primary drive gear may move outward by the offset due to its relationship with the primary driven gear. There is an advantage that the variable flywheel can be set using the idle portion of the crankshaft formed between the bearing and the entire engine can be connected.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

The figure shows a two-cylinder ■-type engine for motorcycles.

In this type engine, a front puncture cylinder 2 and a rear puncture cylinder 3 are arranged in a V-shape with an interval of 90 degrees around the crank 1lQl11'e. A transmission case 5 that is housed in a crankcase 4 with one crankshaft and is connected to the rear.
A counter shaft 6 and a drive shaft 7 are supported in parallel in parallel.

The crankshaft 1 consists of one crank pin 8, on which the connecting rods 9.10 of both cylinders 2.3 are aligned in parallel. Therefore, both cylinders 2 and 3 are offset from each other, and in the figure, the rear puncture cylinder 3 is located on the right side when facing the direction of travel of the vehicle (arrow).

Primary drive gear 11 is located at the right end of the crankshaft 1 above.
is fixed and meshes with the primary driven gear 12 on the counter shaft 6, the primary driven gear 12 and the counter shaft 6 are coupled via a clutch 13, and the counter fi6
A transmission gear mechanism is interposed between the drive shaft 7 and the drive shaft 7. Generator 1 is on the left end of crankshaft 1.
4 is pivotally supported, and drive sprocket gears 15 and 16 for driving the cam of the valve mechanism are provided inside the shaft. 17
, 18 indicate bearings of the crankshaft 1.

Next, the above primary drive gear 11 and the right bearing 1
A machihen flywheel device d19 is shaft-mounted between the 8 and 8. The Machihen flywheel device 19 has a flywheel 20
A drive shoe 21 that is rotatably supported on the crankshaft 1 and rotates integrally with the crankshaft 1 is pressed into contact with the drive shoe 21 by a spring.
The centrifugal force generated by the rotation of the flywheel resists the force of the spring and separates it from the flywheel. In other words, the crankshaft 1 functions as a flywheel in the low speed rotation range, and loses its flywheel function when the speed increases. Therefore, in the low speed range, the moment of inertia of the crankshaft 1 as a whole becomes large, making rotation smooth, and in the high speed range, the moment of inertia is small, making it possible to cope with sudden acceleration, etc., making the engine performance ideal.

〔Effect of the invention〕

With the above configuration and operation, the variable flywheel can be mounted on the crankshaft with good balance. In other words, by arranging the generator and the variable flywheel at both ends of the crankshaft, the recoil moment is well balanced, and since the overhang part of the crankshaft that protrudes outward from the bearing does not increase, it is advantageous for axial runout of the crankshaft. in,
In addition, there is no need to increase the mass of the generator as in the conventional case, which also reduces the burden on the crankshaft.

Furthermore, as shown in the example, when the rear puncture cylinder is offset toward the primary drive gear, the Zoraimai driven gear is positioned outwardly avoiding the rear puncture cylinder, so the Zoraimai drive gear and the crank bearing are There will be an idle part between. Conventionally, a spacer was provided on the crankshaft in this area, but in the present invention, a 9-speed flywheel can be mounted instead of the spacer, which has the effect of making the entire engine more compact.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view of a V-type engine showing an embodiment of the present invention, and FIG. 2 is a cross-sectional plan view taken along the line A--A in FIG. l...Crankshaft, 2...Front puncture cylinder, 3.
... Rear puncture cylinder, 6... Counter shaft, 7...
Drive shaft, 8... Crank pin, 9. lO...Conrod, 11...Zoraimari drive gear, 12.
...Primary r rib gear, I4... Generator, 17.18... Crank bearing, 19... Variable flywheel device.

Claims (1)

[Claims] In a V-type engine in which connecting rods of both cylinders arranged in a V-shape are connected in parallel to one crank pin, a generator is supported on one end of the crankshaft, and a variable flywheel is mounted on the opposite end. A V-type engine characterized by having a primary drive gear pivotally supported at its outer end to transmit power to a transmission gear mechanism.