JPH0531039B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bearing structure in an L-type multi-cylinder engine mounted on a vehicle such as a motorcycle.

Conventionally, for example, an L-type multi-cylinder engine for a motorcycle may be configured as follows. That is, cylinders are provided to protrude from the crankcase toward the front and above of the vehicle, respectively, and the crankshaft, which is interlocked with the pistons of these cylinders, is supported by the crankcase via a sliding bearing. This bearing can be divided into upper and lower parts, and for ease of disassembly and assembly, the crankcase can also be divided into upper and lower parts along a horizontal dividing line passing through the sliding bearing.

By the way, in the above configuration, the dividing surfaces of the bearing and the crankcase have conventionally been formed on the same horizontal plane. Therefore, in this case, the dividing part of the bearing is located on the center line of the cylinder that protrudes forward. ,
The maximum load of explosion pressure in this cylinder will be received by the divided portion of the bearing. As a result, an appropriate oil film cannot be formed on the bearing, resulting in damage to the bearing and the journal portion of the crankshaft.

This invention has been made in view of the above-mentioned circumstances, and is designed to improve the proper relationship between the crankshaft and the bearings while still allowing easy disassembly and assembly of the crankcase in an L-type multi-cylinder engine. The purpose is to ensure an oil film and prevent damage to the bearing.

To achieve the above object, the present invention is characterized in that an L-type multi-cylinder engine for a vehicle has a crankcase that can be divided into upper and lower parts along a substantially horizontal dividing line passing through a plain bearing for the crankshaft.
The dividing plane of the sliding bearing is formed on a plane that is substantially perpendicular to a line that bisects the angle of intersection of the center lines of the front and rear cylinders in side view.

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

A motorcycle 1, which is an example of a vehicle, has a body frame 2.
It has an L-type multi-cylinder engine 3 supported by. Further, a front wheel 6 is supported at the front part of the vehicle body frame 2 via a front fork 4, and a rear wheel 8 is supported at the rear part thereof via a rear arm 7.
This rear wheel 8 is driven by the engine 3.

To explain the engine 3, a front cylinder 11 and a rear cylinder 12 project upward from the crankcase 9 toward the front of the vehicle, respectively, and these cylinders 11,
12 each have a cylinder portion 13 and a not-shown piston inserted into this cylinder portion 13. Both ends of a crankshaft 14 are supported by the crankcase 9 via annular sliding bearings 16, and the crankshaft 14 is interlocked and connected to each of the pistons via connecting rods (not shown). Also,
A transmission shaft 17 and an output shaft 18 are mounted on the crankcase 9 in parallel with the crankshaft 14 on the same plane.
These shafts are interlocked and connected by a speed change gear 19, and the output shaft 18 and the rear wheel 8 are connected by a chain transmission device 21.

The crankcase 9 can be divided vertically along a substantially horizontal dividing line 22 passing through the axes of the sliding bearing 16, the transmission shaft 17, and the output shaft 18, and by this division, the sliding bearing 1
6. The transmission shaft 17 and the output shaft 18 can be attached and detached.

The slide bearing 16 can be divided into two in the radial direction, and this dividing surface 23 is approximately perpendicular to a line 26 that bisects the intersection angle θ of the center lines 24, 24 of the front and rear cylinders 11, 12 in a side view. formed on surface 27. Each divided member of the plain bearing 16 has a bearing housing 28 and a lining 29 provided within the bearing housing 28,
They are fixed to each other by bolts 31 and dowel pins 32. Further, the sliding bearing 16 is prevented from rotating relative to the crankcase 9 by another knock pin 33.

Note that this method may be used for all of the plurality of sliding bearings, or may be used partially, for example, only in the central portion.

According to this invention, since the crankcase can be divided into upper and lower parts along a substantially horizontal dividing line passing through the slide bearing, it is easy to disassemble and assemble the crankcase, and to easily attach and detach the slide bearing. In this configuration, the dividing plane of the sliding bearing is formed on a plane that is almost perpendicular to the line that bisects the angle of intersection of the center lines of the front and rear cylinders when viewed from the side, making it easy to disassemble the crankcase as described above. Although it is a simple configuration, the maximum load of explosion pressure in each cylinder is received at a position that avoids the divided part of the sliding bearing, and therefore an appropriate oil film is created between the crankshaft and the sliding bearing. This prevents damage to these crankshafts and sliding bearings.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a simplified overall side view, FIG. 2 is a partially enlarged cross-sectional view of FIG. 1, and FIG. 3 is a view taken along the - line in FIG. 2. 1... Motorcycle (vehicle), 3... Engine,
11...front cylinder, 12...rear cylinder, 14...crankshaft, 16...sliding bearing, 22...secant line, 2
3... Division plane, 24... Center line, 26... Line, 2
7...face.

Claims (1)

[Claims] 1 A front cylinder is provided protruding from the crankcase toward the front of the vehicle, and a rear cylinder is protruded upward from the vehicle, and a crankshaft linked to these cylinders is supported by the crankcase via a sliding bearing that can be divided into two in the radial direction. , in an L-type multi-cylinder engine for a vehicle in which the crankcase can be divided into upper and lower parts along a substantially horizontal dividing line passing through the sliding bearing, the dividing plane of the sliding bearing is at an intersection angle in side view of the center line of the front and rear cylinders. A bearing structure for an L-type multi-cylinder engine, characterized in that it is formed on a plane substantially perpendicular to a line that bisects the L-type multi-cylinder engine.