JPH108980A - Motorcycle engine - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To shorten the overall length of a crankcase and to concentrate engine mass. A motorcycle engine according to the present invention is configured such that a plurality of rotating shafts are supported on a divided surface of a crankcase configured to be vertically splittable, and these rotating shafts rotate interlockingly via gears. In the motorcycle engine configured as described above, the crankcase 2 is configured to have at least two divided surfaces A and B, and the rotating shafts (11 and 12) directly meshing via the gears (14, 15, 16, 17). And 12 and 13) are respectively supported on different divided planes A and B of the crankcase 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motorcycle engine.

[0002]

2. Description of the Related Art In many multi-cylinder engines mounted on motorcycles, a crankcase is formed into a two-part upper and lower part, and a rotating surface such as a crankshaft, a countershaft, and a drive shaft is supported on the divided surface. Bearing portion is formed. The rotating shafts rotate in conjunction with each other via gears, and a drive shaft is used as an output shaft of the engine.

However, as described above, the crankcase 1
If all of the rotating shafts are supported on one of the divided surfaces, the rotating shafts are aligned in the front-rear direction, so that the total length of the crankcase becomes longer, and there is a tendency that the compactness of the engine is impaired. Further, the mass (mass) of the engine is dispersed back and forth, which is not preferable.

Therefore, as shown in FIG. 2, the crankcase 100 is formed into a three-part upper and lower part, and a crankshaft 101 is supported on an upper parting surface A, and a counter shaft 102 is provided on a lower parting surface B. An engine that supports the drive shaft 103 has appeared. With this configuration, the countershaft 102 is positioned obliquely rearward and downward with respect to the crankshaft 101, and the front-rear distance between the crankshaft 101 and the countershaft 102 is reduced, so that the total length of the crankcase 100 can be shortened accordingly. it can.

[0005]

However, also in the case of the engine shown in FIG. 2, since the counter shaft 102 and the drive shaft 103 are arranged back and forth on the lower divided surface B, this portion is still the entire length of the crankcase 100. Cause the delay.

A motorcycle engine according to the present invention has been invented to solve the above problems, and has as its object to provide a motorcycle engine capable of shortening the overall length of a crankcase.

Another object of the present invention is to concentrate the mass of the engine.

[0008]

In order to achieve the above object, a motorcycle engine according to the present invention is provided with a plurality of split parts on a split surface of a crankcase which can be split vertically. In a motorcycle engine in which the rotating shafts are pivotally supported and these rotating shafts are interlocked and rotated via gears, the crankcase is configured to have at least two divided surfaces, and The rotating shafts that directly mesh with each other are supported on different divided surfaces of the crankcase.

Further, in the motorcycle engine according to the present invention, as described in claim 2, the rotating shafts supported on different divided surfaces of the crankcase are arranged vertically in a side view.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. FIG. 1 is a longitudinal sectional view of a motorcycle engine according to the present invention as viewed from the left side. This engine 1
For example, an in-line four-cylinder four-cycle engine.

The engine 1 is provided with a crankcase 2 located at a lower portion, and a cylinder block 3, a cylinder head 4, and a head cover 5 are fixed on the front upper surface of the crankcase 2 from the bottom in this order. A piston 7 is provided in a cylinder bore 6 formed in the cylinder block 3.
Is slidably inserted, and a valve gear 8 is built in the cylinder head 4 and a carburetor 9 and an exhaust pipe are externally provided.
10 is connected.

On the other hand, a crankshaft
The rotating shaft 11, the counter shaft 12, and the drive shaft 13 are rotatably supported, and these rotating shafts (11, 12, 13) rotate interlockingly via gears. That is, the primary drive gear 14 provided on the crankshaft 11 and the primary driven gear 15 provided on the counter shaft 12 mesh with each other, and the secondary drive gear 16 provided on the counter shaft 12 and the secondary drive gear provided on the drive shaft 13 The driven gear 17 is engaged.

Secondary drive gear 16 and secondary driven gear 17
Is configured such that several gears each having a different number of teeth are arranged in the axial direction so as to always mesh with each other, and these secondary drive gears 16 and secondary driven gears 17,
Shifting forks 18, 19 and shifting drum 2
The transmission 21 is constituted by members such as 0.

A crankpin 22 is eccentrically provided on the crankshaft 11, and the crankpin 22 and a piston pin 23 provided on the piston 7 are connected by a connecting rod 24. Therefore, the reciprocating motion of the piston 7 in the cylinder bore 6 is converted into the rotational motion of the crankshaft 11 via the connecting rod 24. The rotation of the crankshaft 11 is reduced by the primary drive gear 14 and the primary driven gear 15 and transmitted to the counter shaft 12, and the rotation of the counter shaft 12 is controlled by a transmission.
The speed is changed by 21 and transmitted to the drive shaft 13. Then, the rotation of the drive shaft 13 becomes the output of the engine 1.

Incidentally, the crankcase 2 of the engine 1 is configured to be vertically splittable so as to have at least two split surfaces. For example, the upper case 2a, the middle case 2b, and the bottom case 2c are fixed to each other from above to assemble the crankcase 2, and the dividing surface A is formed between the upper case 2a and the middle case 2b.
The dividing plane B is between the middle case 2b and the bottom case 2c.
It has become. An oil pan 25 is fixed to the lower surface of the bottom case 2c.

The rotating shafts that directly mesh with each other via gears are respectively supported on different divided surfaces of the crankcase 2. In other words, the crankshaft 11 and the countershaft directly meshing via the primary drive gear 14 and the primary driven gear 15
The drive shaft 13 meshes with the counter shaft 12 via the secondary drive gear 16 and the secondary driven gear 17, and is separately supported by the split surface A and the split surface B.
It is pivoted on. In the division plane A, the crankshaft 11 is supported on the front side, and the drive shaft 13 is supported on the rear side.

Further, the rotating shafts pivotally supported on different divided surfaces of the crankcase 2 are arranged vertically in a side view. For example, the counter shaft 12 supported on the dividing surface B
Is disposed immediately below the drive shaft 13 that is pivotally supported on the dividing surface A. When viewed from the side, the drive shaft 13 and the counter shaft 12 are vertically arranged parallel to the axis of the cylinder bore 6.

As described above, the crankshaft 11 and the drive shaft 13
Are supported on the dividing surface A, and the counter shaft 12 is supported on the dividing surface B, so that the rotating shafts directly meshing with each other (11 and 12 or
12 and 13) are no longer pivoted on the same dividing plane,
As a result, the three rotating shafts (11, 12, 13) are arranged in a substantially “V” shape in side view, so that the foremost rotating shaft (11) and the last rotating shaft (12, 13) The distance between can be reduced. Therefore, the entire length of the crankcase 2 can be significantly reduced as compared with the conventional engine crankcase indicated by the two-dot chain line C.

Further, since the drive shaft 13 and the counter shaft 12 are arranged vertically above and below in a side view, the three rotating shafts (11, 12, 13) are denser and the mass of the engine 1 is concentrated. be able to.

In this embodiment, the crankshaft 11 and the drive shaft 13 are supported on the upper divided surface A of the crankcase 2 and the counter shaft 12 is supported on the lower divided surface B. The arrangement of the rotating shafts may be different, such that the counter shaft 12 is supported on the upper divided surface A and the crankshaft 11 and the drive shaft 13 are supported on the lower divided surface B. Also in this case, it is preferable to arrange the counter shaft 12 and the drive shaft 13 so as to be vertically arranged in a side view.

In this embodiment, the engine 1 is connected in series 4
Although the cylinder is a four-cycle engine, the present invention can be applied to other types of engines provided that the engine has a vertically split crankcase.

[0022]

As described above, in the motorcycle engine according to the present invention, a plurality of rotary shafts are supported on the split surface of the crankcase which is configured to be vertically splittable, and these rotary shafts are geared. In a motorcycle engine that is configured to rotate in conjunction with each other, the crankcase is configured to have at least two divided surfaces, and the rotating shafts that directly mesh via gears are respectively connected to different divided surfaces of the crankcase. It is characterized by being pivoted.

With this configuration, the rotating shafts that directly mesh with each other are not supported on the same divided surface, but are supported on the frontmost portion and the rearmost portion in the crankcase. Since the distance to the rotating shaft can be reduced, the overall length of the crankcase can be significantly reduced.

Further, in the engine of the motorcycle according to the present invention, the rotating shafts supported on different divided surfaces of the crankcase are arranged so as to be vertically arranged in a side view, so that the rotating shafts are more densely arranged. Can be concentrated.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an engine of a motorcycle viewed from a left side, showing an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of an engine showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Crankcase 11 Crankshaft which is a rotating shaft 12 Counter shaft which is a rotating shaft 13 Drive shaft which is a rotating shaft 14 Primary drive gear 15 Primary driven gear 16 Secondary drive gear 17 Secondary driven gear A, B Split plane of the crankcase

Claims (2)

[Claims] 1. A motorcycle engine in which a plurality of rotating shafts are pivotally supported on a dividing surface of a crankcase configured to be vertically splittable, and these rotating shafts are configured to rotate in conjunction with each other via gears. , The crankcase 2 is configured to have at least two divided surfaces A and B, and the gear (14,
Shafts (11, 12 and
Motorcycle engine 1 characterized in that 12 and 13) are supported on different divided planes A and B of crankcase 2, respectively. 2. Different split surfaces A and B of the crankcase 2
The motorcycle engine (1) according to claim 1, wherein the rotating shafts (11, 12) rotatably supported by the (1) and (2) are arranged vertically in a side view.