JPH0364731B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention mainly relates to a shock absorber for a power transmission mechanism of an engine.

(Prior Art) As shock absorbers for dampening torque fluctuations and impacts, shock absorbers equipped with cam dampers and elastic dampers such as rubber have been known. However, as shown in Figure 1, the conventional shock absorber has gears 1 and 2.
A damper 4 is arranged closer to the driven shaft 3 than the transmission mechanism to buffer torque fluctuations and shocks. Therefore, the fluctuations of the drive shaft 5 itself are transmitted to the gears 1 and 2, and the noise reduction effect of the gears 1 and 2 is small.

Particularly when applied to a gear type power transmission mechanism consisting of a small-diameter crank gear and a large-diameter clutch gear, it is difficult to expect much reduction in noise between the two gears.

(Objective of the invention) It is an object of the present invention to significantly reduce the noise of gears, etc., and to significantly improve the buffering effect of torque fluctuations, etc.

(Structure of the Invention) In order to achieve the above object, the present invention constitutes a gear-type power transmission mechanism by a small-diameter crank gear and a large-diameter clutch gear of a clutch shaft that meshes with the small-diameter crank gear, and the inner peripheral surface of the crank gear is formed into a cylindrical shape. At the same time, a cylindrical body is integrally provided, the cylindrical body is loosely fitted on the outer peripheral surface of the crankshaft, and a cam damper is provided in the inner peripheral cylindrical portion of the crank gear 18 to connect the crank gear 18 and the crankshaft 11 in a twistable manner. 14 and the cam damper 14
A built-in friction damper 15 whose rear surface serves as a pressing surface, and further inside the inner circumferential cylindrical part of the crank gear,
Both dampers have a built-in common damper spring that imparts their respective transmission forces.

FIG. 2 shows the principle of the present invention, in which a crankshaft 11 on the drive side and a clutch shaft 12 on the driven side are interlocked and connected by a gear type power transmission mechanism 13, and A cam damper 14 is provided on the shaft 11 side, and a friction damper 1
5 is set.

(First Embodiment) FIG. 3 is a schematic vertical cross-sectional view of a two-cylinder, two-crankshaft engine, with one crankshaft for each cylinder 16.
1, and both crankshafts 11 are arranged parallel to each other. Both crankshafts 11 are each provided with a crank gear 18, and both crank gears 18 mesh with a clutch gear 21 of a clutch shaft 20. The clutch gear 21 is connected to the clutch shaft 2 via the clutch.
0, and the crank gear 18 is connected to the crankshaft 11 via a shock absorber according to the present invention.

In FIG. 4, which is an enlarged cross-sectional view of FIG. There is. The crank gear 18 is operatively connected to the crankshaft 11 via a cam damper 14 and a friction damper 15.

The cam damper 14 is composed of a follower cam 26 and a cam face 27, and the semicircular follower cam 26 is integrally formed with a support ring 28 and is attached to the outer peripheral spline teeth 2 of the crankshaft 11.
9 is spline-fitted so as to be movable in the axial direction.
The cam face 27 is formed in the cylindrical body 24 in a concave shape. The follower cam 26 is brought into contact with the cam face 27 by the elastic force of the coil spring 30.

The friction damper 15 includes a plurality of first annular plates 31, a plurality of second annular plates 32, and a plurality of annular friction members 33. The first annular plate 31 is spline-fitted to the outer peripheral spline teeth 29 of the crankshaft 11 so as to be movable in the axial direction, and the second annular plate 32 is spline-fitted to the inner peripheral spline teeth 34 of the crank gear 18 so as to be movable in the axial direction. The friction material 33 is welded to the first annular plate 31. Both annular plates 3
1 and 32 are pressed against each other via a friction material 33 by the elastic force of the coil spring 30.

The col spring 30 is compressed between the second annular plate 32 on the arrow F side and the annular spring retainer 35. Further, the first annular plate 31 at the end on the side of the reverse arrow F is connected to the cam damper 14 through the friction material 33.
It is in contact with the support ring 28 of. That is, since the support ring 28 integrally having the follower cam 26 is in contact with the friction material 33 of the friction damper 15, the back surface of the damper 14 is used as a pressing surface of the friction damper 15. 38 is a stopper ring.

(Function) The rotation of the crankshaft 11 is transmitted to the crank gear 18 via the cam damper 14 and the friction damper 15, and is transmitted to the clutch shaft 20 via the clutch gear 21 and the clutch.

Torque fluctuations and impacts of the crankshaft 11 are applied to the follower cam 2 against the elastic force of the spring 30.
6 has a cam damper action that slides against the cam face 27, and the first annular plate 31 and the friction material 33.
is absorbed by the friction damper action of twisting the second annular plate 32 in the rotational direction. The cam damper 14 converts the energy of torque fluctuation into heat and dissipates it.

FIG. 7 shows a load displacement curve due to the friction damper 15, where the displacement θ on the horizontal axis is the twist angle in the rotational direction of the first annular plate 31 with respect to the second annular plate 32, and the load T on the vertical axis is the crankshaft. This is the torsional torque of the shaft 11 (first annular plate 31). HT is the hysteresis torque caused by the friction damper 14.

(Second Embodiment) As shown in FIG. 5, the friction damper 15 includes
an annular member 40 having a tapered friction surface 40a;
The friction member 41 is provided with a three-part friction member 41 (FIG. 6) having a tapered friction surface 41a and an outer peripheral friction surface 41b. The three-part friction member 41 is biased in the direction of the reverse arrow F by the spring 30, so that the tapered friction surface 41a comes into pressure contact with the tapered friction surface 40a of the annular member 40, and both friction surfaces 40
Due to the cam action between a and 41a, each friction member 41 expands radially outward, and the outer peripheral friction surface 41b is pressed against the inner peripheral surface 18a of the crank gear. A sintered alloy is used as the friction member 41, but the friction surface 41
A friction material may be bonded to a and 41b. The shock absorber shown in FIG. 5 is a combination of the friction damper 15 described above and the cam damper 14 similar to that shown in FIG. In FIG. 5, parts corresponding to those in FIG. 4 are given the same numbers as in FIG. 4.

(Effects of the Invention) (1) Since two types of dampers, namely the cam damper 14 and the friction damper 15 are provided, the effect of damping torque fluctuations and impacts of the crankshaft 11 is large.

That is, since it has both the friction damper 5 that converts torque fluctuations into heat and eliminates them, and the cam damper 14 that accumulates torque fluctuations, the effect of buffering torque fluctuations etc. is large.

(2) Since the dampers 14 and 15 are provided closer to the crankshaft 11 than the power transmission mechanism, torque fluctuations of the crankshaft 11 are not transmitted to the gears 18 and 21, which are transmission elements. This prevents damage to gears due to torque fluctuations or impacts, etc.
It is also possible to reduce noise associated with power transmission.

To explain in detail, the engine crankshaft 1
1 and the clutch shaft 12, and is related to a shock absorber for the gear transmission mechanism 13 constituted by the crank gear 18 and the clutch gear 21, and relates to a shock absorber for the gear transmission mechanism 13, which is provided between the crank gear 18 and the clutch shaft 12 on the drive side.
A cam damper 14 and a friction damper 15 are provided between the crankshaft 11 and the crankshaft 11.

Therefore, the crankshaft 11 is attached to the clutch gear 21.
This prevents the clutch gear from being damaged due to torque fluctuations of the crankshaft 11 or impact, thereby extending the life of the clutch gear and the clutch.

In particular, the crankshaft 11 is a member that is directly connected to the engine's pinton via connecting rods, etc., so it is thought that a lot of torque fluctuation will occur, but this is made so that it can be absorbed before it goes to the clutch gear, so it is useful for practical purposes. The effect is significant.

(3) The gear type power transmission mechanism 13 in which the small diameter crank gear 18 and the large diameter clutch gear 21 mesh,
Generally, this is a place where noise is likely to be generated, but since torque fluctuations etc. are absorbed between the drive side crankshaft 11 and crank gear 18, noise generation in the gear type power transmission mechanism 13 is significantly reduced. can.

(4) The inner peripheral surface of the crank gear 18 is formed into a cylindrical shape,
The cylindrical portion of the crank gear 18 houses a cam damper 14 and a friction damper 15 whose rear surface serves as a pressing surface, and a common damper 15 that applies respective transmission forces to both dampers 14 and 15. Since the damper spring 30 is built-in, for example, both the dampers 14, 15 and the crank gear 18 can be assembled to the crankshaft 11 as one unit, and the efficiency of the assembly work is improved.

(5) A cam damper 14 is provided in a cylindrical portion formed on the inner peripheral surface of the crank gear 18, and a friction damper 15 whose back surface is a pressing surface
Since the damper spring 30 is built-in, the power transmission mechanism from the crankshaft 11 to the clutch gear 21 can be made compact.

[Brief explanation of drawings]

Figure 1 is a schematic diagram explaining the principle of the conventional example, Figure 2
The figure is a schematic diagram explaining the principle of the present invention, FIG. 3 is a schematic vertical cross-sectional view of a two-cylinder, two-crankshaft engine to which the present invention is applied, and FIG. 4 is an enlarged cross-sectional view of FIG.
FIG. 5 is an enlarged cross-sectional view of another embodiment (-
6 is a cross-sectional view of FIG. 5, and FIG. 7 is a load displacement curve. 11... Crankshaft, 12... Clutch shaft, 13...
Power transmission mechanism, 14... cam damper, 15... friction damper, 18... crank gear, 21... clutch gear, 30... damper spring.

Claims (1)

[Claims] 1. A gear type power transmission mechanism 13 is constituted by a small diameter crank gear 18 and a large diameter clutch gear 21 of a clutch shaft 20 that meshes with the small diameter crank gear 18, the inner peripheral surface of the crank gear 18 is formed into a cylindrical shape, and a cylindrical body 24 is integrally provided. The cylindrical body 24 is loosely fitted onto the outer circumferential surface of the crankshaft 11, and within the inner circumferential cylindrical portion of the crank gear 18 there is provided a cam damper 14 that connects the crank gear 18 and the crankshaft 11 in a twistable manner;
A friction damper 15 whose rear surface serves as a pressing surface is built in, and a common damper spring 30 is built into the inner circumferential cylindrical portion of the crank gear 18 to impart respective transmission forces to both dampers 14 and 15. A shock absorber for a power transmission mechanism, characterized by: