JPH0225009B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) This invention provides a slant-type engine with an inclined cylinder bore, in which oil that lubricates the valve mechanism at the top of the cylinder head can be quickly transferred to the oil reservoir at the bottom of the crankcase. This invention relates to an engine cylinder block structure in which the cylinder block is returned to the inside of the engine.

(Prior art) A slant-type engine is one in which the cylinder bore is inclined in order to shorten the engine height as much as possible in order to house the engine under the seat, such as in a cab-over vehicle. The oil that accumulates at the bottom of the upper space of the cylinder head due to lubricating the mechanism passes through the oil return passage that runs through the cylinder head and cylinder block almost parallel to the cylinder bore, and falls by gravity into the oil pan at the bottom of the crankcase. However, in conventional engines, the rotation of the crankshaft scrapes up and scatters the oil in the oil reservoir to lubricate the cylinder bore and piston.The oil that is scattered when lubricating the cylinder bore and piston splashes onto the outlet of the oil return passage mentioned above. This was blocking the flow of oil. (For example, Japanese Utility Model Publication No. 1983-19931) If the return of oil from the upper part of the cylinder head is blocked in this way, a large amount of oil will accumulate in the upper part of the cylinder head, and the amount of oil in the oil reservoir will become insufficient and the liquid level will drop. There is a problem that the oil pump cannot suck up enough oil, resulting in insufficient lubrication to various parts of the engine.Furthermore, when the conventional balancer shaft is brought close to the oil return passage, it interferes with the oil and prevents the oil from returning. However, there was a problem in that the cylinder block could not be made compact because the cylinder block was provided so as to protrude laterally.

(Objective of the Invention) This invention solves the above-mentioned problems, quickly returns the oil in the cylinder head to the oil reservoir, maintains the oil level at a normal level, normalizes lubrication, and improves the lubrication of the cylinder block. The object of the present invention is to provide a cylinder block structure for an engine that can be made compact.

(Structure of the Invention) To achieve the above object, the present invention provides an engine cylinder block structure in which the cylinder bore is inclined with respect to the vertical direction of the vehicle in the installed state,
An oil return passage leading from the cylinder head into the crankcase is provided on the back side of the cylinder bore of the cylinder block in parallel with the cylinder bore, and a balancer shaft is disposed close to the outlet of this oil return passage. This is an engine cylinder block structure in which the direction of the rotation locus of the crankshaft and balancer shaft near the outlet of the oil return passage is the same as the direction of oil outflow.

(Example) Examples of the present invention will be described below based on the drawings.

Reference numeral 1 denotes a cylinder block, which is a slant type engine in which the cylinder bore 2 is inclined at approximately 60 degrees from the vertical direction, and a crankcase 3 is formed below the cylinder bore 2.

Reference numeral 4 denotes a cylinder head, which is attached to the upper end of the cylinder block 1 and is connected to the intake/exhaust valves and the valve mechanism 5.
has.

Reference numeral 6 denotes an oil reservoir, which is attached to the lower end of the crankcase 3 and stores oil for lubricating or cooling various parts of the engine.

Reference numeral 7 denotes an oil return passage, which passes through the cylinder block 1 and cylinder head 4 almost parallel to the cylinder bore 2 on the back side of the inclined cylinder bore 2 as shown by the dotted line, and opens an inlet 7a in the upper space of the cylinder head 4. and the outlet 7 is connected to the crankcase 3.
b is opened to allow the oil that collects in the upper space of the cylinder head 4, which lubricates the valve mechanism 5, to return to the crankcase 3 and collect in the oil reservoir 6.

Reference numeral 8 denotes a crankshaft, which is installed horizontally in the crankcase 3, supports the lower end of a connecting rod 10 that raises and lowers a piston 9 in the cylinder bore 2, and also serves to maintain balance with the piston 9 and the connecting rod 10. This counterweight 11 is provided with a counterweight 11 of
The outer end rotates in the direction of the arrow along the locus shown by the two-dot chain line in FIG.

Reference numerals 12 and 12a designate balancer shafts, which are used to remove vibrations caused by the engine's explosion pressure and rotational inertia.On the other hand, the balancer shaft 12 rotates in the direction shown by the arrow, that is, in the opposite direction to the crankshaft 8. , at a position where the outer peripheral trajectory of the balancer shaft 12 approaches the trajectory of the counterweight 11, the rotation direction of the crankshaft 8 and the rotation direction of the balancer shaft 12 are both downward in the same direction as indicated by the arrows in FIG. The outlet 7b of the oil return passage 7 opens above the portion where the trajectory of the counterweight 11 and the trajectory of the outer periphery of the balancer shaft 12 approach.

In this way, the outlet 7b at the lower end of the oil return passage 7
However, since the direction A of the oil flowing down from the outlet 7b of the oil return passage 7 coincides with the direction in which the crankshaft 8 and the balancer shaft 12 approach each other and their trajectories match, the direction A of the oil flowing down from the outlet 7b of the oil return passage 7 coincides. The rotation attracts oil and can quickly return it to the oil reservoir.

Furthermore, if the balancer shaft 12 is provided close to the outlet 7a of the oil return passage, there is no need for the cylinder block 1 to protrude much to the side, and the cylinder block 1 can be made more compact.

13 is an oil level gauge for checking the amount of oil in the oil reservoir 6.

Reference numeral 14 denotes an oil level gauge guide boss, which is provided integrally with a bulk head rib 15 that reinforces between the parallel cylinder bores 2 inside the crankcase 3, and serves as a guide for the oil level gauge 13. .

This oil level gauge guide boss 14 has conventionally been set appropriately depending on the layout, but in a slant type engine such as the one of the present invention, the wall of the crankcase 3 on the front side of the slope is longer. However, by integrating the oil level gauge guide boss 14 with the bulk head rib 15 as described above, the rigidity of the bulk head can be greatly increased. It is.

(Effects of the Invention) According to the present invention described above, when the return oil from the cylinder head flows down into the crankcase through the oil return passage, it collides with the oil scooped up from the oil reservoir by the rotation of the crankshaft. On the contrary, the rotation of the crankshaft and balancer shaft attracts the returning oil and promotes its flow, allowing the oil to quickly return to the oil reservoir and lowering the liquid level in the oil reservoir. In addition to normalizing lubrication by equalizing the amount of oil sucked up by the oil pump and by placing the balancer shaft close to the outlet of the oil return passage, the cylinder block can be configured more compactly. It is something that can be done.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of an engine incorporating the cylinder block of the present invention, and FIG. 2 is a sectional view taken along the line shown in FIG. 1. 1... Cylinder block, 2... Cylinder bore, 3... Crank case, 4... Cylinder head, 5... Valve mechanism, 6... Oil reservoir, 7...
Oil return passage, 7a... Inlet, 7b... Outlet, 8... Crankshaft, 12, 12a...
balance shaft.

Claims (1)

[Claims] 1. An engine cylinder block structure in which the cylinder bore is inclined with respect to the vertical direction of the vehicle in the installed state, and an oil return passage leading from the cylinder head to the inside of the crankcase is provided on the back side of the inclined cylinder bore of the cylinder block. , a balancer shaft is disposed close to the outlet of this oil return passage, and the direction of the rotation locus of the crankshaft and balancer shaft near the outlet of this oil return passage is the same as the direction of oil outflow. The engine's cylinder block structure is characterized by: