JPH03115744A - Multiple cylinder engine - Google Patents

Abstract

PURPOSE:To compact the above engine with two longitudinally displaced cylinders by disposing the crankshaft of the rear cylinder in a higher position than the crankshaft of the front cylinder, and providing a power output shaft frontward below the rear crankshaft. CONSTITUTION:In the case of a two-cylinder engine for a motorcycle with two cylinders 2a, 2b disposed in parallel as well as being displaced laterally by the specified quantity, the rear cylinder 2b is set in a higher position by Z than the front cylinder 2a. Crank gears 19a, 19b are fittingly secured on one sides of the crankshafts 5a, 5b of both cylinders 2a, 2b, and the front crank gear 19a is meshed with the first gear 21 of a primary shaft 20, a power output shaft. The rear crank gear 19b is meshed with a second gear 22 through an idle gear 24. The primary shaft 20 is provided frontward below the crankshaft 5b, and the crankshaft 5a is disposed in a frontward space between the crankshaft 5b and the primary shaft 20.

Description

[Detailed description of the invention] Lord is sitting and standing The present invention relates to a multi-cylinder engine mounted on a vehicle.

Light and compact multi-cylinder engines are required for road vehicle engines such as J and L straight vehicles, especially motorcycles and four-wheelers, in terms of performance such as vibration, fuel consumption, and acceleration, and various improvements have been made to date. has been carried out.

As an improvement of this type, there is one in which multiple cylinders are arranged in a staggered manner when viewed from the center of the cylinder.
In this configuration, as shown in Fig. 1, the crankshafts aSa of each cylinder are arranged at the same height, and the rotation of each crankshaft is controlled by a connecting gear C, which is a power extraction shaft, from a crank gear b, which is integrated with these crankshafts. The rotation of the connecting gear C is transmitted via the connecting gear 1 flywheel gear e to the crankshafts a, which are arranged in a staggered manner, and the flywheel which is disposed behind and at the same height as the crankshafts a and a. The power is transmitted to a main shaft f and a countershaft g that are integrated with the gear e, and a multi-stage gear group is mounted on the main shaft f and the countershaft g.

However, since the above conventional technology sets each crankshaft (a) and a to the same height, the distance between each crankshaft in the direction perpendicular to the cylinder centerline is narrowed. Also, it is difficult to ensure that the main shaft f and counter shaft g, which are connected to crankshaft a and integral crank gear b via connecting gears c and d, lie along the same plane as crankshaft l-a and a. As a result, the length of the transmission case, which houses the crankcase and the large-capacity transmission gear group integrally formed behind it, became long, making it difficult to make the engine lighter and more compact. .

The present invention relates to an improvement of a multi-cylinder engine that overcomes these difficulties, and its purpose is to provide a lightweight and compact multi-cylinder engine. By doing so, the crankcase and the transmission case that extends rearward integrally with the crankcase are shortened in the front-rear direction and can be arranged compactly.

In accordance with the above-mentioned purpose, the present invention integrally includes a mission case for storing a group of mission gears behind the crankcase, and at least two cylinders are disposed offset in the front-rear direction. In a multi-cylinder engine, the crankshaft of the rear cylinder is located higher than the crankshaft of the front cylinder, and the crankshaft of the front cylinder is connected to the crankshaft of the rear cylinder and a power take-off shaft provided below and in front of the crankshaft of the rear cylinder. It is located in the front space between the two crankshafts, and the two crankshafts and the power take-off shaft form a triangle with the longest side being the rear cylinder's crankshaft and the power take-off shaft. The rotation output is integrated into the power take-off shaft and transmitted to the main shaft, mission gear group, countershaft, etc., which are arranged in a relatively wide space behind the rear crankshaft and power take-off shaft.

1 Difference ■ Hereinafter, one embodiment of the present invention shown in FIGS. 2 to 6 will be described. The center line of the cylinder 28.2b remains parallel, and as shown in FIG. A 2-stroke, 2-cylinder gasoline engine for motorcycles that is offset by XSY in the front and back and left and right, with the same cylinder 28.2b
Pistons 3a and 3b are respectively fitted in such a way that they can slide vertically, and the pistons 3a and 3b are connected to cranks (crankshafts) 5a and 5b in crank chambers 6a and 6b via connecting rods 4a and 4b, respectively. has been done.

However, among the cylinders 2, the front cylinder 2a
In contrast, the rear cylinder 2b is set upwardly at a higher position by Z, as shown in FIG.

Further, as shown in FIGS. 3, 5, and 6, the crank chamber 6 includes a parallel surface 10. which extends in the front-rear direction passing through each center line of the cylinders 2a, 2b. a, 1
It is divided vertically into three parts at 0b, each with crank case 7.
．． It is surrounded by 8.9.

Further, behind each of the cylinders 2, as shown in FIG. An exhaust system device 16 consisting of an exhaust boat 14, an exhaust passage 15, etc. is provided in front of each of the cylinders 2, and an exhaust system device 16b is provided near the front cylinder 2a of the rear cylinder 2b, which is one of the cylinders. At the same time, an air supply system device 13a is arranged near the rear cylinder 2b of the front cylinder 2a, which is the other cylinder.

Furthermore, the cylinders 2a, 2b and the crank chambers 6a, 6b are communicated with each other through main scavenging passages 17a, 17b and sub scavenging passages 18a, 18b, similar to a normal crank case scavenging type engine. Although an intake/exhaust operation is performed, other scavenging methods may be used.

However, the crank gears 19a and 119b are located at different levels on the right side of the cranks 5a and 5b (on the near side in FIG. 2).
are fitted together, and the front crank gear 19a
is directly meshed and connected to the first gear 21 of the primary shaft 20, which is a power take-off shaft, and is connected to the rear crank gear 19b.
is connected to the primary shaft 20 via the idle gear 24
The crank gear 19a and the first gear 21, and the crank gear 19b and the second gear 22 are formed to have the same dimensions, and therefore both cranks 5a and 5b are the same. They are designed to rotate in opposite directions at a rotational speed of

As shown in FIG. 2, the primary shaft 20 is provided below and in front of the crank 5b, and is formed by both cranks 5a, 5b and the primary shaft 20 into a triangle whose longest sides are the crank 5h and the primary shaft 20. is formed, and the crank 5a is disposed in a space in front of the crank 5b and the primary shaft 20.

The clutch drive gear 23 of the primary shaft 20 is meshed with a flywheel gear 25 that also serves as a flywheel, and a main shaft 35 of a transmission 34 is pivotally supported around the same rotation center as the flywheel gear 25. 25 and main shaft 35
A multi-plate friction clutch 26 is interposed between the clutches 26 and 26.
, a disk 27 integrated with a flywheel gear 25, a plate 28 integrated with a center clutch 29 connected to a main shaft 35 by a key or spline, and disposed between the disks 27, and a large number of disks 27 and plates 28. A clutch lifter 30 that cooperates with and clamps the center clutch 29, a coil spring 31 that presses the clutch lifter 30 against the center clutch 29, and a clutch cam 33 move the center clutch 29 to the left (upward in the drawing).
When the clutch cam 33 is pushed out and the clutch is disengaged, the slipper rod 32 is twisted.If the cam crest of the clutch cam 33 is not facing leftward (upward in the drawing) as shown in FIG. The clutch 26 is set to the connected state by the force, and when the cam ridge of the clutch cam 33 faces leftward, the clutch 26 is set to the disconnected state.

Further, the transmission 34 has a large number of gears, and has two
The main shaft 35 and the countershaft 40 are configured to be shifted to multiple speed ratios by multi-stage axial movement of the gear shift fork 37, 39 operated by the main gear shift shaft 36, 38. These gear groups are housed in a mission case 53 that is integrally constructed with the crankcase.

Furthermore, a chain drive sprocket 41 is integrally connected to the countershaft 40, and the chain drive sprocket 41 is connected to a chain brocket of a rear wheel (not shown) via a chain.

Therefore, the second gear 2 of the crank gear 19b2 and the primary shaft 20 is attached to the right casing 9 (lower in the drawing).
2 and the idle gear 24.
2 can be detachably attached.

Further, as shown in FIG. 4, the front crank 5a has an alternator 4 on the right side opposite to the crank gear 19a.
The three rotors 44 are fitted together and concentrically.

Furthermore, a drive pinion 4 is located at the left end of the rear crank 5b.
5 are fitted together concentrically, and the same drive pinion 45
A pump impeller 48 is formed concentrically and integrally with a gear 46 that meshes with the gear 46, and the impeller 48 is rotated by the rotation of the rear crank 5b, and the pump 47 for circulating cooling water is rotated by the rotation of the rear crank 5b.
is now driven.

Since the illustrated embodiment is configured as described above, when the engine 1 is started with a starter (not illustrated), the front crank 5a rotates clockwise, for example.
The rear crank 5b rotates in the opposite direction at the same rotation speed as the front crank 5a.

In this state, the rotational torque of the front crank 5a is transmitted to the main shaft of the transmission 34 via the crank gear 19a, the first gear 21, the primary shaft 20, the clutch drive gear 23, the flywheel gear 25, and the multi-disc friction clutch 26. It is transmitted to the shaft 35, reduced to an appropriate gear ratio by the transmission 34, and transmitted to the chain sprocket 41, and the rear wheel is driven via a chain wheel (not shown) and a rear wheel chain sprocket, so that the motorcycle can run. Become.

Further, the rotational torque of the rear crank 5b is transmitted to the primary shaft 20 via the crank gear 19b, the idle gear 24, and the second gear 22, and thereafter is transmitted to the rear wheel in the same manner as the torque transmission of the front crank 5a. Reportedly.

Furthermore, as the engine 1 operates, the rear air supply system device 13
a, 13b vaporizer 12a, reed valve Ila, 1
1b crank chambers 6a, 6b and main scavenging passage 17a,
Cylinder 2 via 17b, 18a, 18b
The air-fuel mixture is taken into the cylinders 8.2b, and the combustion gas in the cylinders 2a and 2b is scavenged to the exhaust board 4a of the exhaust system devices 16a and 16b located in the front.
, 14b and exhaust passages 15a, 15b.

However, as shown in FIG. 2, since the cylinder 2b located at the rear by Z is located above the front cylinder 28, the engine The front-to-back dimensions of the whole 1 can be further reduced.

Furthermore, the crank gear 19 is connected via the idle gear 24.
b is connected to the second gear 22 of the primary shaft 20, the main shaft 35 of the transmission 34
Since the engine 1 and the transmission 34 can be moved forward, the overall dimensions of the engine 1 and the transmission 34 can be made compact.

In addition, since the crank chamber 6 is divided into three parts by the planes 10a and 10b which pass through the center line of both pistons 2a and 2b and are perpendicular to the crankshaft, the crank chamber 6 is divided into three parts by the axes of the cranks 5a and 5b, the primary shaft 20, and the transmission 34.
The main shaft 35 and counter shift 40 of the engine 1 and the transmission 3 do not need to be located on the same plane.
4 can be made sufficiently compact, the engine 1 can be easily processed, and the engine 1 is lightweight but has high rigidity.

In the embodiment described above, there were two cylinders, but it is also possible to have three or more cylinders, and in the case of an odd number, bilateral symmetry can be obtained.

In the above embodiment, the front crank 5a is connected to the primary shaft 20 via the crank gear 19a and the first gear 21, and the rear crank 5b is connected to the primary shaft 20 via the crank gear 19b, the idle gear 24, and the second gear 22. - It was connected to the shaft 20, but the seventh
Chain brockets 49. are attached to the cranks 5a, 5b and the primary shaft 20, as shown in the figure.
50.51 and the same chain sprocket 49.5
An endless chain 52 may be installed at 0.51 mm, and in such an embodiment, substantially the same effect as in the previous embodiment can be achieved, except that the cranks 5a and 5b both rotate in the same direction. .

In the embodiments described above, the present invention was applied to a two-stroke gasoline engine, but the present invention can also be applied to a four-stroke gasoline engine and other two- or four-stroke diesel engines.

Although the present invention has been described above in detail with respect to the embodiments shown in the drawings and the embodiments not shown in the drawings, the present invention is not limited to such embodiments and can be modified without departing from the spirit of the invention. The design can be freely modified as needed.

In the claimed invention, the crankshaft of the rear cylinder is located higher than the crankshaft of the front cylinder. The mutual spacing can be further narrowed, structural members related to the front and rear cylinders can be integrated, and the engine can be made lighter and more compact.

In addition, the power take-off shaft is provided below and in front of the crankshaft of the rear cylinder, and the triangle formed by both crankshafts and the power take-off shaft is formed into a triangle whose longest side is the line connecting the rear crankshaft and the power take-off shaft. Therefore, the space before and after the line connecting the rear crankshaft and the power take-off shaft can be used effectively, and in particular, the mission gear group can be interposed and arranged in the wide effective space created at the rear formed by the shaft arrangement. As a result, the length of the crankcase and the transmission case integrally connected to the crankcase in the front-rear direction can be shortened.

Since the longitudinal length of the entire engine can be shortened in this way, further compactness can be achieved.

[Brief explanation of drawings]

FIG. 1 is a longitudinal side view of a conventional multi-cylinder engine, FIG. 2 is a longitudinal side view of an embodiment of the multi-cylinder engine according to the present invention, and FIGS. 3 to 6 are -■ line, I
FIG. 7 is a cross-sectional view taken along lines V--IV, .--., and .--. FIG. 7 is a vertical sectional side view of a main part of another embodiment of the present invention. ■... Engine, 2... Cylinder, 3... Piston, 4... Connecting rod, 5... Crank, 6... Crank chamber, 7, 8.9... Crank case, 10 ...Dividing surface, 11... Reed valve, 12
... Carburizer, 13... Air supply system device, 14... Exhaust boat, 15... Exhaust passage, 16... Exhaust system device,
17...Main scavenging passage, 18...Sub scavenging passage, 19
... Crank gear, 20... Primary shaft, 21... First gear, 22... Second gear, 23...
・Clutch drive gear, 24...Idle gear, 2
5... Flywheel gear, 26... Multi-plate friction clutch, 27... Disc, 28... Plate, 29...
...Center clutch, 30...Clutch lifter, 31
...Coil spring, 32...Lifter rod, 3
3...Clutch cam, 34...Transmission, 35...Main shaft, 36...Gear shift shaft, 37...Gear shift fork, 38...Gear shift shaft, 39...Gear shift fork, 4
0... Counter shift, 41... Chain drive sprocket, 42... Auxiliary cover, 43... Alternator, 44... Rotor, 45... Drive pinion, 46... Gear, 47 ...Cooling water circulation pump,
48...Pump impeller, 49.50.51...
Chain sprocket, 52... Endless chain, 5
3...Mission case.

Claims (1)

[Claims] A mission case is integrally provided behind the crankcase to house a group of mission gears, and at least two
In a multi-cylinder engine in which the cylinders are arranged offset in the front-rear direction, the crankshaft of the rear cylinder is arranged higher than the crankshaft of the front cylinder, and the crankshaft of the front cylinder is placed above the rear cylinder. It is installed in the front space between the crankshaft and the power take-off shaft located below and in front of it.
A multi-cylinder engine characterized in that both crankshafts and the power take-off shaft form a triangle whose longest side is the rear cylinder's crankshaft and the power take-off shaft.