JP3631902B2 - Vibration reduction damper - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vibration reduction damper that reduces the vibration of a rotating shaft that generates both torsional vibration and longitudinal vibration in a crankshaft for a diesel engine.
[0002]
[Prior art]
FIG. 5 shows an example of a viscous friction damper conventionally used for reducing torsional vibration of a shaft system in a diesel engine.
[0003]
In FIG. 5, reference numeral 1 denotes a crankshaft of a diesel engine, and a damper casing 2 is fixed to a shaft end by a bolt 6.
Reference numeral 2a denotes an annular damper chamber provided in the damper casing 2. An annular inertia ring 4 is accommodated in the damper chamber 2a with a predetermined minute gap 5a and a damping oil 5 is enclosed. ing.
Reference numeral 3 denotes a cover of the damper chamber 2a, which is fixed to the damper casing 2 by bolts 20.
[0004]
In such a viscous friction damper, when a torsional vibration as shown in Y of FIG. 5 occurs on the crankshaft, the mass of the inertia ring 4 is applied to the circumferential vibration of the damper casing 2 fixed to the crankshaft 1. A relative displacement occurs between the damper casing 2 and the inertia ring 4, and the torsional vibration is attenuated by reducing the relative displacement by the viscous friction of the damping oil 5 enclosed in the damper chamber 2a.
FIG. 6 is a vibration curve of the crankshaft system of the diesel engine. A shows a case where no vibration reduction damper is installed, and B shows a case where a viscous friction damper as shown in FIG. 5 is installed.
[0005]
[Problems to be solved by the invention]
In the viscous friction damper according to the prior art, the inertia ring 4 is not supported at all with respect to the rotating damper casing 2 and is in a freely rotating state. Therefore, a mechanically supported vibration system cannot be formed, and therefore the vibration damping effect is limited.
[0006]
Further, in the crankshaft of the diesel engine, particularly the crankshaft of a large marine diesel engine, in addition to the torsional vibration, an in-cylinder pressure or a propeller shaft system thrust is used as an excitation source, as indicated by an arrow X in FIG. Such longitudinal vibration in the axial direction is generated.
For this reason, in a diesel engine having a crankshaft on which such torsional vibration and longitudinal vibration act, a longitudinal vibration damper for attenuating longitudinal vibration is provided in addition to the torsional vibration reducing damper as shown in FIG. There is a problem that the structure is complicated and large, and the manufacturing cost is high.
[0007]
In view of the problems of the prior art, the present invention enables reduction of both torsional vibration and longitudinal vibration with a single damper, and the damping effect of these vibrations is improved. It is another object of the present invention to provide a low-cost vibration reduction damper for a rotating shaft.
[0008]
[Means for Solving the Problems]
In order to solve this problem, the present invention provides the first invention as follows:
In a vibration reduction damper for a rotating shaft that is attached to a rotating shaft that rotates with vibrations such as torsional vibration and longitudinal vibration, and that reduces vibration of the rotating shaft,
A plurality of spherical damping chambers provided inside the casing fixed to the rotating shaft;
Each of the damping chambers so as to be capable of rolling, and together with both the torsional vibration and the longitudinal vibration of the rotating shaft, the spherical body and the spherical together they constitute at and the spheres hard steel or copper alloys materials remembering rolling friction force between the inner wall of the damping chamber,
The casing is a spherical case that functions as an attenuation chamber, and the spherical case is formed by fitting a cover having a hemispherical portion and a casing main body to reduce vibration of the rotating shaft. Propose a damper.
[0009]
According to this invention, the spherical body freely rolls and moves in an arbitrary direction in accordance with the direction of the vibration through the damper casing by the vibration acting on the rotating shaft. Due to the rolling of the sphere, the sphere comes into contact with the inner wall surface of the damping chamber, and this contact generates a rolling frictional force having a phase of 90 ° with respect to the vibration of the damper casing between the sphere and the inner wall surface of the damping chamber. The rolling frictional force acts as a damping force for the vibration, and torsional vibration and / or longitudinal vibration can be reduced.
[0010]
According to a second aspect of the present invention, in the first aspect of the present invention, the damping chamber is formed by adhering a plurality of friction materials made of lead or rubber to the inner wall surface at intervals.
[0011]
According to this invention, since the friction material having a large friction coefficient such as lead is fixed to the inner wall surface of the damping chamber, the rolling friction force is further increased by the contact between the sphere and the friction material, and an even greater vibration reduction effect is obtained. It is done.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Only.
[0013]
1 is a cross-sectional view taken along the axial center line of a vibration reduction damper for a diesel engine according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1, and FIG.
[0014]
1 and 2, reference numeral 1 denotes a crankshaft of a diesel engine, and a damper casing 2 is fixed to a shaft end by a plurality of bolts 6.
Reference numeral 3 denotes a cover, which is fitted to the damper casing 2 via inlay portions 21 and 22 and fixed by a plurality of bolts 20.
Reference numeral 7 denotes a ball case formed inside the damper casing 2 and the cover 3. As shown in FIG. 2, a plurality of (6 in this example) spherical cases 7 are provided at equal intervals in the circumferential direction, and as shown in FIG. Each hemisphere is formed.
[0015]
A plurality of leads 9 are embedded in the inner surface of each spherical case 7. As shown in FIG. 3, a plurality of the leads 9 are embedded in the inner surface of the spherical case 7 at substantially equal intervals, and the surface is finished smoothly by simultaneous processing with the inner surface of the spherical case 7.
Reference numeral 8 denotes a sphere inserted into each of the ball cases 7, the outer diameter of which is sufficiently smaller than the inner diameter of the ball case 7 so that the ball case 7 can freely roll.
[0016]
The relationship between the inner diameter of the ball case 7 and the outer diameter of the ball 8 and the number of cases 7 and 8 are set to suitable values depending on the torsional vibration and longitudinal vibration of the diesel engine to which the vibration reducing damper is applied. .
The sphere 8 is made of a material having a relatively large specific gravity, such as a copper alloy, in addition to a hard steel material.
[0017]
During operation of a marine diesel engine equipped with a vibration reduction damper having such a configuration, the crankshaft 1 has a longitudinal axis indicated by an X arrow in FIG. 1 caused by torsional vibration from the engine indicated by an Y arrow in FIG. Vibration occurs.
[0018]
Due to the torsional vibration and the longitudinal vibration, the sphere 8 freely rolls in the sphere case 7 in an arbitrary direction according to the vibration direction. Then, the ball 8 comes into contact with the inner wall surface of the ball case 7 including the surface of the lead 9 by rolling and moving in the ball case 7, so that the ball 8 is interposed between the ball 8 and the inner wall surface of the ball case 7. Rolling friction force is generated.
This rolling frictional force acts as a damping force having a phase of 90 ° with respect to the vibration of the crankshaft 1 and the damper casing 2, whereby the torsional vibration and / or longitudinal vibration is attenuated.
[0019]
Here, since the lead 9 having a large friction coefficient is embedded in the inner surface of the ball case 7, the rolling friction force between the two is further increased when the ball 8 contacts the surface of the lead 9.
[0020]
As described above, according to this embodiment, the vibration of the crankshaft 1 is caused by the rolling friction force between the sphere 8 and the inner wall surface of the sphere case 7 when the sphere 8 rolls and moves in the sphere case 7. Since the vibration is damped, it is possible to attenuate not only the torsional vibration acting in the circumferential direction and the longitudinal vibration acting in the axial direction but also the vibration in the three-dimensional direction.
[0021]
FIG. 4 shows a vibration curve in the crankshaft 1. In FIG. 4, A is a vibration curve in the above embodiment when A is not provided with a vibration damping damper as in FIG.
As shown in FIG. 4, in the embodiment of the present invention indicated by C, a vibration reduction effect greater than that of the conventional viscous friction damper shown in FIG. 6B is obtained.
[0022]
【The invention's effect】
As described above, according to the present invention, the sphere in the damping chamber provided in the casing rolls in the damping chamber in an arbitrary direction due to torsional vibration or longitudinal vibration generated in the rotating shaft and the casing fixed to the rotating shaft. Thus, the rolling friction force generated by the contact between the inner wall surface of the damping chamber and the sphere acts as a damping force of the vibration, and attenuates and reduces vibrations in all directions including the torsional vibration and longitudinal vibration. It becomes possible.
[0023]
In particular, according to the second aspect, since a friction material such as lead having a large friction coefficient is fixed to the inner wall surface of the damping chamber, the rolling friction force is further increased, and a higher vibration reduction effect can be obtained. .
[0024]
Therefore, according to the present invention, a vibration damping effect that can simultaneously reduce torsional vibration and longitudinal vibration with a very simple and compact structure in which a spherical body is housed in a spherical damping chamber provided inside the casing is increased. A vibration reduction damper can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view taken along the rotational axis of a vibration reduction damper of a diesel engine according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is an inner surface view of a sphere case in the embodiment.
FIG. 4 is a vibration curve in the embodiment.
FIG. 5 is a view corresponding to FIG. 1 of a vibration reduction damper according to the prior art.
FIG. 6 is a vibration curve in the prior art.
[Explanation of symbols]
1 Crankshaft 2 Damper casing 3 Cover 6 Bolt 7 Ball case 8 Ball 9 Lead

Claims (2)

In a vibration reduction damper for a rotating shaft that is attached to a rotating shaft that rotates with vibrations such as torsional vibration and longitudinal vibration, and that reduces vibration of the rotating shaft,
A plurality of spherical damping chambers provided inside the casing fixed to the rotating shaft;
Each of the damping chambers so as to be capable of rolling, and together with both the torsional vibration and the longitudinal vibration of the rotating shaft, the spherical body and the spherical together they constitute at and the spheres hard steel or copper alloys materials remembering rolling friction force between the inner wall of the damping chamber,
The casing is a spherical case that functions as an attenuation chamber, and the spherical case is formed by fitting a cover having a hemispherical portion and a casing main body to reduce vibration of the rotating shaft. damper. 2. The vibration reduction damper for a rotating shaft according to claim 1, wherein the damping chamber is formed by fixing a plurality of friction materials made of lead or rubber on the inner wall surface at intervals. 3.

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