JPS5827081Y2 - Cylinder structure of opposed cylinder engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cylinder structure for an opposed-cylinder engine with six or more cylinders, and particularly to a structure for facilitating the assembly of pistons, connecting rods, and crankshafts.

When a piston and a crankshaft are connected by a connecting rod, the piston and the connecting rod are generally connected by a piston, which is inserted into a cylinder, and the large end of the connecting rod is connected to the crankshaft.

Such a coupling method is described, for example, in Japanese Patent Application Laid-Open No. 51-31308.
As seen in the above publication, this method is also used in multi-cylinder opposed engines.

However, in opposed-cylinder engines that have a structure in which the crankshaft is clamped between the left and right crankcases that are integrated with the cylinder block, and the clamping parts are arranged opposite to the piston insertion hole, the piston does not fit into the cylinder. This makes it difficult to connect the connecting rod to the crankshaft, making it especially difficult to assemble the piston in the central cylinder of an engine with six or more cylinders.

Therefore, in some conventional engines, a large hole is drilled in the top of the crankcase for work purposes, and the connecting rod is connected to the crankshaft by inserting one's hand through the hole.

However, because such holes are provided in conventional engines, the rigidity of the crankcase decreases, and a large sealing device is required to close the holes, resulting in an increase in the number of machining processes. was.

The present invention aims to provide a cylinder structure that does not have such drawbacks.In a dry liner/one-way type engine, the cylinder structure penetrates through the lower part of each cylinder of each bank and is parallel to and coaxial with the crankshaft. A piston pin is inserted into the piston in the central cylinder and the connecting rod through the service hole so that the piston pin and the connecting rod can be connected to each other.

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings.

The figure shows a part of a horizontally opposed six-cylinder engine.2 In the figure, 1 and 2 are left and right bank blocks that serve as cylinders and crankcases, respectively.
．． They each form a crankcase 4.

In each block, service holes 5゜6, 7, and 8 are provided in the lower part of each cylinder and are located parallel to and on the same axis as the crankshaft, passing through each cylinder part and the cylinder liner 9. There is.

These service holes are provided in such a position that the pin hole of the piston pin 11 coincides with this hole when the piston 10 is located at the bottom dead center, but unlike the above-mentioned conventional service holes, they are provided in the upper surface of the crankcase. It is extremely small compared to the large working hole that was previously used.

Note that the front and rear service holes 5 and 8 are sealed with relatively small lids (not shown).

The cylinder and piston are assembled using the cylinder structure according to the present invention as follows.

First, attach each connecting rod 13 to the crankshaft 12, and connect the left and right blocks 1 with this crankshaft in the center.
, 2.

To assemble the pistons into the central cylinders 3a and 3b,
The connecting rod of one of the cylinders is at the bottom dead center position, the piston 10 is inserted into this cylinder from above, the pin hole of the piston pin 11 is aligned with the small end of the connecting rod, and the piston 10 is placed on either side of the cylinder. Using a long and narrow special tool, insert the piston pin 11 with a circlip attached to one end of the service hole 5 or 8 to join them together, and then connect the circlip 14 to the piston pin 11 and the pin. Insert it so that it spans the circumferential wall of the hole to prevent the piston pin from coming out.

A piston and a connecting rod can be similarly assembled and connected to the center cylinder on the other side.

Similarly, the piston pin 11. is inserted into each outer cylinder from the service hole. A circlip 14 can be inserted to join the piston to the connecting rod.

Furthermore, cylinder heads (not shown) are mounted on the cylinders of the blocks 1 and 2, and the service holes 5.8 on the front and rear sides of the blocks 1 and 2 are sealed with relatively small lids.

As is clear from the above, according to the present invention, there is no need to drill a large hole in the upper surface of the crankcase to accommodate the hand for connecting the connecting rod to the crankshaft, as is the case with conventional methods, so the rigidity of the crankcase is improved. Also, since there is no large sealing device to close the hole, processing is also simplified.

Furthermore, since the sealing surface is smaller, there is less worry about oil leakage, etc., and the service holes on both sides of the central cylinder are used as air passages within the crankcase, ensuring good blow-by gas circulation. This has the effect that the internal pressure of the gas in the crankcase becomes almost uniform in each cylinder, thereby reducing fluctuations in the oil level in the oil pan and reducing the amount of oil escaping together with the blow-by gas.

[Brief explanation of the drawing]

FIG. 1 is a cutaway plan view of a horizontally opposed six-cylinder engine to which the present invention is applied, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIG. 3 is an exploded perspective view. 1.2...Block, 3...Cylinder, 4...Crankcase, 5,6,7,8...Service hole,
9... Cylinder liner, 10... Piston, 11.
...Piston pin, 12...Crankshaft, 13...
Connecting rod, 14...circlip.

Claims (1)

[Scope of utility model registration request] The engine body is divided into left and right blocks around the crankshaft, and each block is provided with a crankcase part and at least three or more cylinder parts,
A service hole is provided in the lower part of each cylinder of each block, parallel to and coaxial with the crankshaft, and this service hole is aligned with the piston pin hole of the piston at bottom dead center. A cylinder structure for an opposed cylinder engine, characterized in that the cylinder structure is formed so that a piston pin that connects a piston and a connecting rod and a circlip that prevents the piston pin from coming out can be inserted thereinto.