JP3072395B2 - Multi-cylinder engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-cylinder engine in which a power take-out portion for driving a valve mechanism and a power take-out portion for driving an auxiliary machine are provided on a crankshaft of a plurality of cylinders.

[0002]

2. Description of the Related Art For example, a motorcycle is equipped with a multi-cylinder engine having a plurality of cylinders. A crankshaft of such a multi-cylinder engine has a power take-out section for driving a valve operating mechanism, a generator, an oil pump and the like. And a power take-out unit for driving the auxiliary machine.

[0003]

As described above, a power take-out part for driving a valve mechanism and a power take-out part for driving an auxiliary machine are sometimes provided on a crankshaft of a multi-cylinder engine. In some cases, depending on the arrangement of the valve operating mechanism and the auxiliary equipment, a power take-out part for driving the valve operating mechanism and a power take-out part for driving the auxiliary equipment may be provided between the central cylinders of the plurality of cylinders.

When a power take-out portion for driving a valve mechanism and a power take-out portion for driving an auxiliary machine are provided between the central cylinders of a plurality of cylinders as described above, a crank bearing may be provided between the two. Although the support of the crankshaft is ensured, the crankshaft becomes longer by the provision of the crank bearing, and as a result, the width of the multi-cylinder engine in the crankshaft direction is increased.

It is an object of the present invention to provide a multi-cylinder engine capable of securely supporting a crankshaft without increasing the width in the crankshaft direction.

[0006]

In order to solve the above-mentioned problems, a multi-cylinder engine according to the present invention has a crank bearing which supports a crank shaft between each of a plurality of cylinders. The crankshaft is provided with a power take-out portion for driving a valve operating mechanism, and a pair of crank bearings are disposed between the central cylinders with the power take-out portion of the valve operating mechanism interposed therebetween. A power take-out part for driving an auxiliary machine with a crank bearing opposite to the power take-out part to be driven provided on the crankshaft; and a power take-out part for driving the valve mechanism is a power take-out part for driving the auxiliary machine. And is offset from the center between the cylinders to the opposite side.

[0007]

According to the present invention, a pair of crank bearings are arranged between the central cylinders of the plurality of cylinders with the power take-out portion of the valve mechanism interposed therebetween. A power take-out portion for driving the auxiliary machine is provided on the crankshaft, and the crankshaft is reliably supported by the crank bearing. In addition, the power take-out section that drives the valve mechanism is provided offset from the center between the cylinders on the side opposite to the power take-out section that drives the auxiliary equipment, and without increasing the width in the crankshaft direction, the crankshaft can be used. I support it.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a side view in which a part of the multi-cylinder engine is cut away, FIG. 2 is a cross-sectional view showing a structure for attaching an auxiliary device to the multi-cylinder engine, and FIG.

In the drawing, reference numeral 1 denotes a parallel four-cylinder multi-cylinder engine mounted on a motorcycle, and a crankcase 2 of the multi-cylinder engine 1 is composed of upper and lower crankcases 3 and 4. A cylinder block 5 is mounted on 3. A cylinder head 6 is mounted on the cylinder block 5, and a valve case 7 is fastened and fixed to the cylinder head 6 with bolts 8. A head cover 9 is mounted on the valve case 7, and these constitute a cylinder.

A pair of cam shafts 11 of a valve operating mechanism 10 for operating an intake valve and an exhaust valve (not shown) are rotatably supported on the valve case 7.
The small-diameter sprocket 1 provided on the crankshaft 14 via the cam chain 13
5, and the sprocket 15 constitutes a power take-out unit for driving the valve train 10. This valve train 10
May be a gear integrally formed with the crankshaft 14 instead of the sprocket 15.

The cam chain 13 is prevented from swaying by a guide member 16, and a guide member 17 is disposed on the opposite side of the guide member 16, and a predetermined tension is applied by a chain tensioner 18 via the guide member 17. I have. Further, the cam chain 13 is provided with the valve case 7.
The lifting is suppressed by the holding member 19 provided at the bottom.

A large-diameter sprocket 20 is provided on the crankshaft 14, and the sprocket 20 is connected to a sprocket 24 provided on a drive shaft 23 of a generator 22 via a drive chain 21.
Constitutes a power take-out section for driving auxiliary equipment. The power take-out part that drives this accessory may be a gear integrally formed with the crankshaft 14 instead of the sprocket 20. In this embodiment, the generator 22 constitutes an auxiliary machine, but the auxiliary machine may be an oil pump or the like.

A starter motor 25 is disposed near the generator 22.
Is engaged with a large-diameter gear portion 28a of a reduction gear 28 rotatably provided on a support shaft 27, and the small-diameter gear portion 28b of the one-way clutch 29 provided on the drive shaft 23 of the generator 22. It is in mesh with the gear 30.
Therefore, when the starter motor 25 is driven, the rotational force is reduced by the reduction gear 28 and transmitted to the one-way clutch 29. The drive shaft 23 of the generator 22 is rotated via the one-way clutch 29, and the rotational force is 24 via the drive chain 21 to the crankshaft 14
And the crankshaft 14 is forcibly rotated to start.

By starting the engine, the crankshaft 1
4 is increased from the sprocket 20 of the crankshaft 14 via the drive chain 21 to the generator 2.
The power is transmitted to the sprocket 24 of the second drive shaft 23 to drive the generator 22. At this time, the one-way clutch 29 blocks the transmission of the rotational force of the drive shaft 23 of the generator 22 to the starter motor 25 side.

Both ends 14a of the crankshaft 14 are supported by crank bearings 3a and 4a on the side of the upper and lower crankcases 3 and 4, respectively, and both ends 14a are covered with caps 100. The upper and lower crankcases 3 and 4 include a crankshaft 14 between each of the plurality of cylinders.
Bearings 3b1, 4b1,
3b2 and 4b2 are integrally formed and arranged, and the sprockets 15, 2 are attached to the crankshaft 14 at positions between the central cylinders.
0 is provided. Further, a pair of crank bearings 3 is provided between the central cylinders with a sprocket 15 of the valve train 10 interposed therebetween.
b2, 4b2, and the crank bearing 3b on the opposite side of the sprocket 15 for driving the valve train 10
A sprocket 20 for driving the auxiliary machine is disposed with the 2 and 4b2 interposed therebetween.

A sprocket 15 for driving the valve train 10 is provided at a predetermined distance D from a center L between the cylinders on a side opposite to the sprocket 20 for driving an auxiliary machine.
Without increasing the width of the crankshaft, the crankshaft 14
I support.

An oil passage 31 is formed at the bottom of the lower crankcase 4, and branch passages 32, 33 formed in the crank bearings 4a, 4b1, 4b2 are formed in the oil passage 31.
Are provided in communication with each other, and oil is supplied to the bearing portion from the branch passages 32 and 33.

A pin 14d is formed on the crankshaft 14 between a pair of four arms 14c.
A connecting rod 34 is rotatably mounted on the connecting rod 34, and a piston 35 is connected through the connecting rod 34. The piston 35 is connected to a sleeve 36 fitted to the cylinder block.
It is provided so that it can reciprocate inside. This crankshaft 14
A weight is provided on one of the pair of arms 14c, and a weight 14e is provided on the arm 14c opposite to the left and right crank bearings 3b1, 4b1 provided on the upper and lower crankcases 3, 4. I have. In this way, when the weight is provided on the arm 14c of the crankshaft 14, the arm 14c is not provided on the center crank bearings 3b2 and 4b2, but is provided opposite to each other with the left and right crank bearings 3b1 and 4b1 interposed therebetween, thereby achieving balance. ing.

Further, the arm 14 of the crankshaft 14 of the cylinder to which the sprocket 20 at the center of the plurality of cylinders is attached.
A reduction gear 37 is formed in c, and the power of the crankshaft 14 is extracted from the reduction gear 37 and transmitted to a transmission (not shown). A rotational speed detector 38 is provided on one side of the upper crankcase 3.

[0020]

As described above, according to the present invention, a pair of crank bearings are arranged between the central cylinders of a plurality of cylinders with a power take-out portion of a valve train interposed therebetween, and a power take-out portion for driving the valve train is provided. Since the power take-out portion for driving the auxiliary machine is provided on the crankshaft with the crankshaft on the opposite side interposed therebetween, the crankshaft can be reliably supported by the crankshaft.

The power take-out section for driving the valve operating mechanism is provided on the opposite side to the power take-out section for driving the auxiliary machine and offset from the center between the cylinders. Also, even if a crank bearing is provided between the power take-out portion for driving the auxiliary machine, the crankshaft can be reliably supported without increasing the width in the crankshaft direction.

[Brief description of the drawings]

FIG. 1 is a side view in which a part of a multi-cylinder engine is cut away.

FIG. 2 is a cross-sectional view showing a structure for attaching an accessory to a multi-cylinder engine.

FIG. 3 is a sectional view taken along line III-III in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multi-cylinder engine 3 Upper crankcase 4 Lower crankcase 3b1, 4b1, 3b2, 4b2 Crank bearing 10 Valve train 14 Crankshaft

Claims (1)

(57) [Claims] 1. A crank bearing which supports a crankshaft is disposed between each of a plurality of cylinders, and a power take-out portion for driving a valve mechanism is provided on the crankshaft at a position between the central cylinders. A pair of crank bearings are arranged between the central cylinders with the power take-out portion of the valve mechanism interposed therebetween, and a power take-out that drives an auxiliary machine with a power take-out portion that drives the valve drive mechanism and a crank bearing opposite to the power take-out portion. And a power take-out part for driving the valve train is offset from a center between the cylinders on a side opposite to a power take-out part for driving the auxiliary machine. Cylinder engine.