JPS591837A - Crank balancer mechanism for v-type engine - Google Patents

Abstract

PURPOSE:To prevent the generation of unbalanced couple of forces in a whole crank system by arranging a rotational body provided with a balance weight reversely rotating in the equal speed with a crank shaft round an axis almost in parallel with the crank shaft for offsetting the unbalanced couple of forces in the direction of the crank shaft. CONSTITUTION:In this construction, when a crank 13 is rotated, cam shafts 32 and 35 are rotated via a cam chain 37. A sprocket 36b with a balance weight 36a on a shaft 35 is reversely rotated at a fixed phase relation and an equal number of revolutions with the crank shaft 13. This construction permits to work a force to offset the unbalanced couple of forces in the longitudinal direction of the crank shaft caused in the crank shaft 13 by the slippage of (h') between positions of two con-rods 18 for preventing the generation of unbalanced couple of forces in a whole crank system.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a crank balancer mechanism for canceling an unbalanced couple that occurs with rotation of a crankshaft in a V-type engine.

A V-type engine has two cylinders arranged in a V-shape.
For example, it is used in motorcycles and other vehicles.

As shown in Fig. 7 (a) and (b) K, when the included angle θ formed by the λ cylinders of this V-type engine is Oo, then 7
Both connecting rods 2 are connected side by side to one common crank bin 1, and the web of the crankshaft 3 (attached to the crank arm) is used to maintain approximately 9 degrees of rotation during the rotation of the crank system.
A counterweight 5 is provided on the side opposite to the crank bin 1 of No. 4.

6 indicates a piston.

Like this? :, included angle θ between two cylinders O
o, the primary unbalanced inertial force of the crank system can be eliminated by the counterway 5 provided as described above. And the two connecting rods 2 in the case of
As shown in Figure 7 (b) VC, the threads h in the crankshaft length direction are sufficiently small due to the connecting rods 2 being attached to the common crank bin 1, so the threads h occur in the crankshaft direction. However, when the included angle θ formed by the λ cylinders is not 00te, if two contorrados are connected to the common crank bin, even if a counterweight is provided on the web, the above-mentioned 7-order Unbalanced inertia cannot be resolved. In order to eliminate this 7th order unbalanced inertia force, Figure 1 (a) and (b)
As shown in the figure, connect the connecting rods 2 of both cylinders to the crankshaft 3.
Two crank bins IK provided in phase with the center rotation of the crankshaft 3 (that is, at positions shifted in the circumferential direction) are connected to the web 4 of The counterweights 5 are provided at substantially symmetrical positions with respect to. In this way, the linear unbalanced inertia force described in A + J can be resolved, but as shown in Figure 1 (b) VC, the deviation h' of the center of gravity of the λ cylinders becomes large, so ^ II. The balance couple in the direction of the crankshaft increases and shifts.

This invention was proposed in view of the above-mentioned circumstances.In an L ft V type: r-engine, connecting rods are connected to two crank bins provided in phase with the center rotation of the crankshaft. The object of this invention is to provide a crank balancer mechanism that can cancel out unbalanced couples.

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

FIG. 3 shows a motorcycle equipped with a V-type engine 11 with a horizontal crankshaft to which the crank balancer mechanism of the present invention is applied. λ cylinders 12 are V when viewed from the side of the vehicle body.
The crankshaft 13 extends in the width direction of the vehicle body.

14 is a sectional view of a main part of the V-type engine shown in FIG. 3, taken along a vertical plane in the longitudinal direction of the vehicle body; 15 is a cylinder block, 16 is a cylinder head, 17 is a piston, and 18 is a connecting rod.

Two crank bins 20 are attached to the web 19 of the crankshaft 13 (corresponding to a crank arm).
3 is mounted in phase with the center rotation (that is, the 4th is shifted by an angle α in the figure). Further, in this case, it is preferable to maintain the relationship between θ and α: α; / t Oo−20. The λ crank bins 20 are formed integrally with both in]ic intermediate webs 21 of the intermediate webs 21. The two connecting rods 18 are respectively connected to the respective crank bins 20 so as to be offset by a dimension h' in the length direction of the crankshaft 13. Therefore, the central axes of the two cylinders 12 are also 1a1<h'. The crankshaft 13 is shifted in the longitudinal direction. In addition, the web 19 has a center of gravity at a position (arrow (A)) that is approximately symmetrical with respect to the circumferential intermediate position of the two crank bins 20 and the center of the crankshaft, as described in the conventional example shown in FIG. A counterweight 22 is provided.

On one end side of the crankshaft 13, a primary chain y, 2
A drive gear 24 for transmitting power to a transmission (not shown) through a is fixed, and a starting gear 25 is fixed to the outside of the vehicle body in line with this drive gear 24, and this starting gear 25 is connected to a starter 26. output shaft 27
is connected to via a gear 28. 29 is a one-sided clutch that connects the starting gear 25 and the crankshaft 13.

A tin rocket 30 is fixed to the other end of the crankshaft 13, and a flow generator 31 is provided at the tip.

The valve mechanism Vi of the engine of this embodiment is of the Radcam type, and each cylinder head 16 is provided with a camshaft 32, and one end of the camshaft 32 is equipped with a double-row chain truss as shown in the figure. A driven sprocket 33 is fixed.

The above configuration is substantially the same as the conventional one, but in the present invention, the crankshaft 13 is placed in the crankcase 14 at the bottom A of the V bank of the V-type engine in the upper direction of the crankshaft 13 in the camcheno chamber 34. A shaft 35 parallel to the above is mounted on the shaft 35, and a sprocket 36b having a balance weight 36a integrally formed thereon is rotatably mounted on the shaft 35. This tin rocket 36b has the same number of teeth as the sprocket 30 on the crankshaft 13.

Sprocket 30 on crankshaft 13. ．． As shown in FIG. 6, the IJK of the tin rocket 36b integrated with the two camshafts 32 and 32, and the balance weight 36a is as shown in FIG.
The cam chain 37 is wound around the sprocket 36b so that the sprocket 36b rotates in the opposite direction to the rotation of the other sprockets 30, 30, that is, in the opposite direction to the rotation of the crankshaft 13.
It passes under the camshaft 32.32 and is wrapped around the λ sprockets 33.33TIC.

The vicinity of the shaft 35 of the cam chain chamber 34 is made slightly wider in the longitudinal direction of the crankshaft 13 than usual in order to accommodate the balance weight 36a.

Next, the operation will be explained.

When the J pistons 17 reciprocate at a fixed timing to rotate the crankshaft 13 via the connecting rod 18, the counterweight 22 provided on the web 19 of the crankshaft 13 causes a linear displacement in the rotational direction of the crankshaft 13. The equilibrium inertial force cancels σ.

On the other hand, the sprocket 3 that rotates together with the crankshaft 13
0 drives the sprocket 33 of the camshaft 32 via the υ cam changer 37, the camshaft 32 rotates, and opens and closes an intake valve and an exhaust valve (not shown). ° Then, the cam chain 37 rotates the tin rocket 36b on the shaft 35 in the opposite direction to the crankshaft 13 at the same rotation speed. Therefore, the balance weight 3 integrated with the sprocket 36b
6a reverses the rotation of the shaft 35 at the same rotation speed as the crankshaft 13 in a certain phase relationship with the crankshaft 13. In this S-stroke, since the positions of the two connecting rods 18 are shifted by h' in the crankshaft length direction, an unbalanced couple in the crankshaft length direction is generated on the shift flank shaft 13 itself. An unbalanced couple acts on the crankcase 14, but the balance weight 36a that rotates the rotation wheel 11135 acts to cancel the unbalanced couple acting on the crankcase 14, so the crank system as a whole is affected. This means that no balanced couple will occur.

Regarding the phase relationship between the crankshaft 13 and the balance weight 36a, which is set to cancel the unbalanced couple, the counterweight 22 of the crank-h13 may be attached differently. 22
The shape varies depending on the production method, such as forging, casting, or press-fitting. In addition, in the embodiment, the sprocket 36b rotates on the shaft 35, but the sprocket 36b and the shaft 3
Of course, the shaft 35 itself may rotate 194 times when the shaft 35 is integrated with the shaft 35.

Further, in the above-described embodiment, the rotating body is composed of the sprocket 36b and the camchin 37FC! fi-driven, but the invention is not limited to this; (b) the rolling element may be composed of gears and may be driven by a gear provided on the crankshaft 13; in short, it may be driven in conjunction with the crankshaft 13 Axis line parallel to the crankshaft 13 Rotate the crankshaft 13 by 4 degrees.
vCiI in the opposite direction at the same rotation speed! ! Anything that moves is good.

As explained above, in the present invention, a rotating body whose axis is approximately parallel to the crankshaft rotates in the opposite direction at the same rotational speed as the crankshaft in conjunction with the rotation of the crankshaft is provided. Since a balance weight is provided, this balance weight acts to cancel out the unbalanced couple in the direction of the crankshaft that occurs on the crankshaft, thereby preventing the above-mentioned unbalanced couple from occurring in the crank system as a whole. Possible 1. In addition, in the case where the rotating body is configured with a tin rocket installed in the cam chain chamber, and this rotating body with a balance weight is moved by a cam chain, the cam chain is installed near the rotating body. By simply making the chamber slightly wider in the longitudinal direction of the crankshaft, a rotating body can be provided with a simple structure by effectively utilizing the V-bank of a V-type engine.

[Brief explanation of drawings]

Figures 7 (a) and (b) show that the included angle between the two cylinders is P.
OO: General rank shaft coupling explanatory diagram for a V-type engine, w, ko diagram (A), (B) Fi: General for a V-type engine where the included angle between the two cylinders is not 90° Figure 3 is a schematic side view of a motorcycle equipped with a V-type engine to which the crank balancer mechanism of the present invention is applied. 7 is a cross-sectional view of a main part of the V-type engine in FIG. 3 in a vertical plane in the longitudinal direction of the vehicle body, FIG. 5 is a cross-sectional view of a main part of the V-type engine in FIG. FIG. 6 is an explanatory diagram of the chain winding loss due to the Vl-■ thin cross section in FIG. 5. 12...Cylinder, 13...Crankshaft, 14...Crankcase, 15...
・Cylinder block, 16...Cylinder head, 17...Piston, 18...Conrod 5.19...Web, 20...Crank Bottle, 22... Counterweight, 30
...Tin rocket, 32...Camshaft, 33...Suffu mouth/kerat, 34...
...Cam chain chamber, 35...Shaft, 36a
...Balance weight, 36b... Sprocket (rotating body), 37... Cam chain. Figure 1 (Rof Figure 2)

Claims (1)

[Claims] The center of ko cylinders is 1! ti+ #l! The pistons in each cylinder are arranged in a V-shape, and the pistons in each cylinder are connected to connecting rods. In each connected V-type engine, a rotating body is provided that rotates in the opposite direction at the same rotational speed as the crankshaft in conjunction with the rotation VC of the crankshaft, whose axis is approximately parallel to the crankshaft, and this rotating body has a balance. The crank balancer mechanism of the V engine is specially designed with weights.