JPH03281901A - V-type offset engine - Google Patents

Abstract

PURPOSE:To reduce each surface height of cylinders so as to obtain a compact V-type engine having a small height by offsetting axes of the cylinders in the same direction (i.e., in the crankshaft rotating direction) with respect to the center of a crankshaft. CONSTITUTION:Pistons 2A, 2B are slidably inserted into cylinders 1A, 1B constituting fore and rear banks, and are connected to a crankshaft 4 via connecting rods 3A, 3B. The axes l1, l2 of the cylinders 1A, 1B are offset by a distance epsilonwith respect to the center O of the crankshaft 4 in the crankshaft rotating direction (i.e., in the direction indicated by an arrow in Fig. 1), respectively. Accordingly, each surface height of the cylinders 1A, 1B can be reduced to a value (h). Therefore, each length of the connecting rods 3A, 3B as well as the whole height H of an engine can be reduced to a small value, thus obtaining a compact V-type offset engine of a small size.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a V-type offset engine in which a cylinder axis is offset with respect to the center of a crankshaft.

(Conventional technology) With a normal V-type engine (standard engine).

As shown in FIG. 3, the cylinder axis n-'l of each cylinder,
° passes over the crankshaft center 0, and the surface height h' of the cylinders IA' and IB' forming the front and rear banks (the length from the crankshaft center 0 to the lower end surface of the cylinders IA' and IB') and connecting rods. The lengths of 3A' and 3B' can be shortened to the extent that the cylinders IA'' and IB' interfere with each other as shown in the figure, and they can be shortened further to make the engine smaller and more compact. I can't even plan.

By the way, a so-called offset engine is known in which the cylinder axis is offset from the center of the crankshaft. According to this engine, it is possible to change the maximum value of the piston side pressure and the timing at which the maximum value occurs, and as a result, the sliding of the piston is The dynamic loss can be kept small.

The present invention has been made based on the publicly known technology related to the above-mentioned offset engine, and its purpose is to provide a small and compact 3-type offset engine with low piston sliding loss and low height. .

(Means for Solving the Problems) In order to achieve the above object, the present invention comprises a V-type offset engine by offsetting the cylinder axis of each cylinder in the direction of rotation of the crankshaft with respect to the center of the crankshaft. Its characteristics.

(Function) As in the present invention, when the cylinder axes of each cylinder of a ■-type engine are offset in the same direction (rotation direction of the crankshaft) with respect to the center of the crankshaft, the cylinders forming the front and rear banks or the cylinders interfering with each other. The surface height (the length from the center of the crankshaft to the lower end surface of the cylinder) can be made shorter than that of a standard engine, and as a result, a compact engine with a low height can be obtained.

(Example) An example of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a cross-sectional view of the essential parts of a ■-type offset engine according to the present invention, and FIG. 2 is a diagram illustrating the geometrical relationship of the same engine in comparison with a standard engine.

In FIG. 1, IA and IB are cylinders forming front and rear banks, and these cylinders IA and IB have pistons 2A and 2A.
, 2B are each slidably fitted. The pistons 2A, 2B are connected via connecting rods 3A, 3B, respectively, to a crankshaft 4 extending in a direction perpendicular to the plane of the paper in FIG.

In this embodiment, the axes (axis center lines) of cylinders IA and IB □, 9, 2 are aligned in the direction of rotation of the crankshaft (in the direction of the arrow in FIG. 1) with respect to the center 0 of the crankshaft 4. offset by the amount ε.

By the way, in Fig. 2, the cylinders of the standard engine (see Fig. 3) are indicated by chain lines IA'' and IB', and if the diameters of these cylinders IA' and 1B' are both D, then in the standard engine, the above-mentioned cylinder IA', IB
'Cylinder IA' as long as the cylinders interfere with each other.
, IB' (in FIG. 2, h' indicates the minimum value of the cylinder surface height).

Here, the surface height of cylinders IA' and IB' is h
′ remains the axis line statement.

If they are translated in parallel by 12 degrees or ε (same as the offset amount ε of the V-type offset engine according to this embodiment) in the crankshaft rotational direction with respect to the crankshaft center O, these will be as shown in Fig. 2. Move to the positions indicated by IA'' and IB'', and at this time there is a gap (margin) of δ between them.
occurs. Therefore, until the gap δ=O, the cylinder IA
By moving "IB" toward the crankshaft center O direction, a V-type offset engine according to this embodiment can be obtained, and according to this, the surface height of the cylinders IA and IB can be adjusted to h (=h'-δ) as shown in the figure.
), so connecting rods 3A, 3B
By keeping the length and overall height of the engine low, it is possible to obtain a small and compact V-type offset engine. In addition, also in this embodiment, the piston 2A
.

Of course, the effect already known for offset engines can be obtained by suppressing the sliding loss of the 2B.

By the way, when a V-type offset engine is configured as described above, a part of the lower end of one cylinder IA enters the lower end surface of the other cylinder and interferes with the connecting rod 3B, as shown in FIG. Is it necessary to cut a part of -1 and leave it there?

(Effects of the Invention) As is clear from the above description, according to the present invention, the crank axis of each cylinder of the V-type engine is offset in the direction of rotation of the crankshaft with respect to the center of the crankshaft. , a compact V-type offset engine can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the main parts of a V-type offset engine according to the present invention, Fig. 2 is a diagram illustrating the geometrical relationship of the engine in comparison with a standard engine, and Fig. 3 is a main part of a V-type standard engine. FIG. IA, IB-...Cylinder, 4...Crankshaft, X,
, St, -... Crank axis line, 0... Crank shaft center, e... Offset amount.

Claims (1)

[Claims] V characterized in that the cylinder axis of each cylinder is offset in the direction of rotation of the crankshaft with respect to the center of the crankshaft.
type offset engine.