JPH08338476A - Crankshaft damper - Google Patents

Abstract

PURPOSE: To reduce double vibrations by bending in two directions orthogonal with each other almost vertical to the axis of, a crankshaft with a single damper simultaneously, in this crankshaft damper which absorbs any vibrations in a bending direction to the crankshaft to be produced in a driving system of the crankshaft or the like. CONSTITUTION: A damper 64 consisting of a damper weight 68 and an elastic body 70 elastically supporting this damper weight 68 is attached to the side surface in the axial direction of a crankshaft 62X of a rotator rotating integrally with the crankshaft 62, and the elastic body 70 is formed into a point symmetrical, nonroundness and nonannular form in relation to the crankshaft 62, and in this constitution, it is so constituted that bending vibrations in two directions are simultaneously reducible by this damper 64 alone.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crankshaft damper which absorbs vibrations generated in a drive system such as a crankshaft in a bending direction with respect to the crankshaft.

[0002]

2. Description of the Related Art Generally, a damper device in which an inertial mass is formed at one end of an engine crankshaft through an elastic body is used as a means for reducing the vibration of the crankshaft. Two types of vibrations are generated on the crankshaft, vibrations in the torsional direction and vibrations in the bending direction.
In order to reduce vibration, it is necessary to suppress the above two vibrations as low as possible.

As a conventional technique for simultaneously reducing the vibration in the twisting direction and the vibration in the bending direction with a single damper, there is, for example, Japanese Utility Model Laid-Open No. 2-34846. According to the description of Japanese Utility Model Publication No. 34846/1990, the technique shown in FIG. 5 is described as a conventional example. In the damper pulley 11 shown in FIG. 5, the vibration reducing damper 12 used for reducing the vibration in the twisting direction is provided with the void 14 in the rubber portion 13 so as to function also as the bending vibration damper. It is a thing.

However, the damper pulley 11 of the type described above
In the bending vibration, when the natural vibrations are different from each other in two directions orthogonal to each other in FIG. 5B, that is, in the a direction and the b direction, the rubber is shaken in the direction perpendicular to the crankshaft direction of the crankshaft 1. The portion 13 elastically deforms the rubber material in the tensile and compression directions, but the spring constant is low because there is no rubber portion 13 in the a direction, and the spring constant is high because there is the rubber portion 13 in the b direction.

As described above, in the damper provided on the outer circumference in the radial direction of the damper pulley 11 and changing in the circumferential direction,
When the crankshaft 1 rotates, its vibration characteristics have a directivity, which is extremely undesirable. Further, when braking the bending in the b direction, the rubber undergoes compressive and tensile strains, so there is a risk that the durability of the rubber will decrease as compared with the case where the rubber undergoes the strain in the shearing direction.

In order to solve the above-mentioned various problems, the technique described in Japanese Utility Model Laid-Open No. 2-34846 is proposed. According to the technique described in Japanese Utility Model Laid-Open No. 2-34846, as shown in FIG. 6, a belt winding portion 31 on the outer peripheral side of a pulley 30 mounted on the crankshaft and a hub portion 32 on the inner peripheral side are connected. The rubber elastic body 50 is connected to the connecting portion 33.
The damper mass 40 is vulcanized and bonded via
Moreover, the rubber elastic body 50 is provided with a curled portion 55.

The rubber elastic member 50 and the damper mass 40 constitute a vibration damper which is composed of an inertial mass of the damper mass 40 and a spring in the torsional direction of the rubber elastic member 50, and absorbs vibrations in the torsional direction of a rotating shaft such as a crankshaft. In addition, a vibration damper configured by the mass of the damper mass 40 and the spring in the bending direction of the rubber elastic body 50 to absorb the bending direction vibration of the rotating shaft such as the crank shaft is configured.

In the case of this conventional example, the torsion spring of the rubber elastic body 50 is determined by the spring strength of the rubber elastic body 50 that is elastically deformed by shearing around the axial center of the pulley 30. The bending direction spring is determined by the spring strength of the rubber elastic body 50 that is elastically shear-deformed by the rubber in the plane orthogonal to the axis of the pulley 30.

According to the technique described in the above publication, the rubber elastic body 50 is shown in FIGS. 6 and 7 in order to reduce the vibration in the twisting direction and the vibration in the bending direction. as described above, even if changing the position and the number thereof providing the hollow portions 55, the spring constant Kr of the bending direction, Kr ≒ (GA / h) · ^{[1 + 4h 2/9 (D} 1 2 +
D ₂ ² )] ^-1 , where D ₁ .. Since D ₂ >> h, the directional term has a very small value, so the expression of K _r is
About GA / h (G: rubber shear modulus, A: area of rubber elastic body, h: thickness of rubber elastic body, D ₁ ; outer shape of rubber elastic body 50, D ₂ ; inner diameter of rubber elastic body 50), The spring constant in the bending direction is mainly determined by the cross-sectional area A and the thickness h thereof, and is formed so that the directivity is not substantially present.

That is, in the technique described in the publication, as shown in Table 1 of the publication in FIGS. 6 and 7, the direction a (the direction in which the curled portion 55 exists) and the direction b (the curled portion 55 does not exist). Direction), the bending direction spring constants are substantially the same. Further, since the technique described in the above publication does not want the vibration characteristics to have directionality,
Aiming to keep the spring constant Kr constant in the circumferential direction,
Kr ≒ (GA / h) · ^{[1 + 4h 2/9 (D} 1 2 +
D ₂ ² )] ⁻¹ , h and D ₁ D ₂ have a non-round shape that changes in the circumferential direction.

[0011]

However, as is well known, the bending vibration generated in the crankshaft of the engine is a combustion explosion caused by the rotation of the crankshaft of the engine, as shown by the chain double-dashed line in FIG. Although the bending forces in the X and Y directions are generated on the two types of the crankshaft axes due to the force and the inertial force, the deformation of only the bending force in the Y direction is shown.

Due to these two kinds of bending forces, the bending resonance frequency of the crank shaft generated in the straight line Y direction connecting the center line of the clan shaft and the crank pin, and the crank shaft generated in the X direction orthogonal to the straight line. The bending vibrations are different from each other in the X-axis and Y-axis directions of the crankshaft. This vertical bending in the Y direction has a gap between the crank arms 3a and 3b of the crankshaft 1 as shown by the chain double-dashed line in FIG. 5, and the crank arms 3a and 3b open and close while the engine is rotating. Therefore, it is easy to bend in the vertical direction, and in the X direction, the crankshaft 1
a. Since the crank arms 3a and 3b and the crank pin 2 are provided and the crank shaft has a substantially continuous structure, it is difficult to bend in the X direction.

Therefore, although not shown, the bending damper that has been generally used in the past has an axisymmetric structure,
It is clear that the same resonance frequency is set for both the bending in the X direction and the bending in the Y direction, and the bending vibration cannot be effectively reduced. The curling portion 55 provided on the rubber elastic body 50 of the damper pulley having the axial symmetry as in the technique described in JP-A-2-34846 changes the position and number of the curling portion arranged with respect to the rubber elastic body 50, and at first glance, the Y It is observed that different resonance frequencies are generated for bending in the X-direction and in the X-direction. However, even if the damper pulley is attached to the crankshaft, as described above, the actual open flat plate 2-3484 is used.
In the damper pulley of the technique described in Japanese Patent No. 6, since the bending resonance frequencies (spring constants) in the Y direction and the X direction have substantially the same value, it is impossible to simultaneously reduce the bending vibrations of the crankshaft in the Y direction and the X direction. It cannot be done.

That is, according to the description of the publication, the bending vibration can also be reduced, but since the bending resonance frequencies (spring constants) in the Y direction and the X direction are substantially the same as described above, The spring constant is an average value of the bending resonance frequencies (spring constants) in the Y and X directions, or only one co-frequency as a bending damper of the damper pulley can be set. Of the bending vibrations in the direction, the Y that makes a large contribution to the reduction of the bending vibrations.
It is considered that the conventional damper pulley is tuned so as to reduce only the vertical bending vibration in the vertical direction and cannot effectively reduce the bending vibration of the crankshaft.

Therefore, the damper pulley of the conventional example has no effect of simultaneously reducing the bending vibrations in the X and Y directions with one rubber elastic body, and suppresses the bending vibrations of the rubber elastic body. In the damper device that changes in the circumferential direction as shown in FIG. 3, when the vibration in the bending direction is damped, the rubber elastic body is subjected to compressive and tensile strains, which may reduce its durability and is effective. The above vibration cannot be reduced.

The present invention has been made in view of the above problems, and the crank axis line of the rotating body that rotates the damper composed of the damper weight and the elastic body that elastically supports the damper weight integrally with the crank shaft. Mounted on the side of the direction,
At least one of the damper weight and the elastic body is formed in a non-circular non-circular shape that is point-symmetric with respect to the rotation axis, and the bending vibration in the Y direction and the bending vibration in the X direction are combined into one damper. It is an object of the present invention to provide a crankshaft damper that can be simultaneously reduced.

[0017]

Therefore, a crankshaft damper of the present invention according to claim 1 is provided with a rotating body which is provided on the crankshaft and rotates integrally with the crankshaft, and a direction of the rotating body in the crankshaft axis direction. And a damper weight supported by an elastic body provided on a side surface of the elastic body, the elastic body being formed in a non-circular non-circular shape that is point-symmetric with respect to the crankshaft.

According to a second aspect of the present invention, in the crankshaft damper of the first aspect, at least the elastic body of the damper weight and the elastic body is formed into an elliptical ring shape. There is. According to a third aspect of the present invention, in the crankshaft damper according to the first or second aspect, at least the elastic weight of the damper weight and the elastic body has a non-circular non-circular or elliptical major axis. Is arranged substantially along a straight line connecting the crank shaft pin of the crank shaft to the crank shaft, and the minor axis of the non-circular or elliptical ring is relative to the straight line connecting the crank shaft line and the crank shaft pin. It is characterized in that they are arranged along a substantially orthogonal line.

A crankshaft damper according to a fourth aspect of the present invention is the crankshaft damper according to the first or second aspect, in which at least the elastic body of the damper weight and the elastic body is the non-circular non-circular or elliptical ring. The major axis of the non-circular or elliptical annular minor axis is arranged along a plane that divides the angle between the adjacent crank arms in the axial projection of the crankshaft into two substantially equal parts. It is characterized in that it is arranged along an orthogonal line that is substantially orthogonal to a plane including the axis of the crank and the above plane.

According to a fifth aspect of the present invention, there is provided a crankshaft damper according to the first aspect, wherein the elastic body is made of natural or synthetic resin rubber. I am trying. A crankshaft damper according to a sixth aspect of the present invention is characterized in that, in the configuration according to any of the first to fifth aspects, the rotating body provided on the crankshaft is a belt pulley, a chain sprocket, or a gear. There is.

According to a seventh aspect of the present invention, in the crankshaft damper of the first aspect, the elastic body and the damper weight are formed in substantially the same shape. There is.

[0022]

In the crankshaft damper according to the first aspect of the present invention, the damper weight is supported by the rotating body that rotates integrally with the crankshaft and the elastic body provided on the side surface of the rotating body in the crankshaft axis direction. And the elastic body is formed in a non-circular non-circular shape that is point-symmetric with respect to the crank shaft, and therefore, for two modes of longitudinal bending and lateral bending of the crank shaft having different resonance frequencies, A single damper can exert the function of a dynamic damper.

In the crankshaft damper of the present invention as defined in claim 2, since at least the elastic body of the elastic body and the damper weight is formed in an elliptical ring shape, the longitudinal bending generated in the crankshaft is caused. It is possible to effectively resonate with the transverse bending vibration and act to reduce the vibration. Further, since the ratio of the length of the elliptic ring-shaped elastic body to the length of the minor axis can be accurately determined, the length and the short length are adjusted so as to be suitable for the vibration due to the bending in the direction substantially perpendicular to the crank axis. The ratio of the length of the diameter can be selected.

According to a third aspect of the present invention, there is provided a crankshaft damper according to claim 3, wherein at least the elastic weight of the damper weight and the elastic body has a major axis of the non-circular non-circular or elliptical ring from the crank axis. An orthogonal line that is arranged substantially along a straight line connecting the crankshaft pins of the crankshaft, and the minor axis of the non-circular or elliptical ring is substantially orthogonal to the straight line connecting the crankshaft axis and the crankshaft pin. The damper can be effectively resonated with the longitudinal bending and lateral bending vibrations generated in the crankshaft.

Further, since it is possible to accurately determine the ratio of the length of the at least one of the elliptic ring-shaped elastic body and the damper weight to the length of the minor axis, it is possible to bend in a direction substantially perpendicular to the crank axis. The ratio of the length to the minor axis can be selected to suit vibration.
In the crankshaft damper of the present invention according to claim 4, in the damper weight and the elastic body, at least the elastic body has a non-perfect circular non-annular or elliptical annular major axis, which is a projection view in the axial direction of the crank shaft. In such a manner that the angle formed by the crank arms adjacent to each other is roughly bisected and arranged along a plane, and the minor axis of the non-circular or elliptical ring is the plane including the axis of the crank and the plane. Since the dampers are arranged so as to be substantially orthogonal to each other, the damper can effectively resonate with the vertical bending and horizontal bending vibrations generated in the crankshaft even in the V-type engine.

In the crankshaft damper of the fifth aspect of the present invention, since the elastic body is formed of a natural or synthetic resin rubber material, it is possible to effectively resonate with the bending vibration of the crankshaft. You can In the crankshaft damper of the present invention as set forth in claim 6, since the rotating body provided on the crankshaft is a belt pulley, a chain sprocket or a gear, the rotating body provided on the crankshaft is not particularly provided. It can resonate with bending vibration.

In the crankshaft damper of the present invention as defined in claim 7, the elastic body and the damper weight are formed in substantially the same shape, and the entire rear surface of the damper weight is fixed to the side surface of the rotating body. Therefore, stable desired resonance vibration can be generated. Also, since the ratio of the length of the elliptical annular damper weight to the length of the minor axis can be accurately determined, the major axis and the minor axis are adjusted so as to be suitable for vibration due to bending in a direction substantially perpendicular to the crank axis. The ratio of the lengths of the can be selected.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. First, FIGS. 1 to 4 show an embodiment, FIG. 1 is a schematic explanatory view showing an embodiment of the present invention, FIG. 2 is a schematic explanatory view seen from the arrow P of FIG. 1, and FIG. 3 is a damper weight of FIG. And a schematic view of a rubber elastic body alone, FIG. 4 is a schematic view for analysis of the crankshaft damper of FIG. 1, and (A) is a front view of the damper,
FIG. 4B is a sectional view taken along line 4B-4B in FIG.

FIG. 1 shows a crankshaft 6 of an in-line 4-cylinder engine.
2 is schematically shown by its axial center line, and the crankshaft damper 64 of the present invention is attached to the shaft end portion of the crankshaft 62.
A damper pulley 66 to which is attached is installed. The damper pulley 66 is, as shown in FIGS.
6, a damper mass 68, and a rubber elastic body 70.

As shown in FIGS. 1 to 3, the damper pulley 66 is made of a material such as metal or resin, and has a belt groove portion 72, which engages with a belt (not shown), formed on the outer periphery of the damper pulley 66. Attached to the belt groove 7
2. A tubular hub portion 74 that extends in the crank axis direction is formed on the inner peripheral side of the second portion 2, and is connected between the belt groove portion 72 and the hub portion 74 to connect the belt groove portion 72 and the hub portion 74. have.

Although not shown, the damper pulley 66 is attached to the crankshaft 62 by being fitted on the inner peripheral surface of the hub portion 74 and fixed by being prevented from rotating with a key or the like. Dampa Mas 6
8 is an inner circumference 78 of the belt groove portion 72 and an outer circumference 80 of the hub portion 74.
Also, it is arranged in a space limited by the connecting portion 76. The damper mass 68 has an outer circumference 82 having a smaller diameter than the inner circumference 78 of the belt groove portion 72, an inner circumference 84 having a larger diameter than the outer circumference 80 of the hub portion 74, and has a desired axial direction of the hub portion 74. It is formed in an elliptical ring having a thickness.

The shape of the damper mass 68 is not limited to the elliptical ring shape, and may be any non-circular non-circular ring shape. Further, of the end faces 68a, 68b of the hub portion 74 of the damper mass 68, the side surface 68b of the damper mass 68 on the side facing the connecting portion 76 is formed of a flat surface extending substantially parallel to the side surface 76a of the connecting portion 76. ing.

The damper mass 68 is fixed by vulcanization joining a rubber elastic body 70 interposed between the side surface 68b of the damper mass 68 and the connecting portion 76. The rubber elastic body 7
0 is an outer circumference 86 having substantially the same diameter as the outer peripheral surface 82 of the damper mass 68, and an inner circumference 8 having substantially the same diameter as the inner circumference 84 of the damper mass 68.
8, a side surface 70b forming a flat surface adhered to the connecting portion 76 of the damper pulley 66, and a side surface 68b of the damper mass 68.
And a side surface 70a forming a flat surface adhered to the.

The rubber elastic body 70 configured as described above.
The damper mass 68 constitutes a vibration damper which is composed of an inertial mass of the damper mass 68 and a torsion spring of the rubber elastic body 70 to absorb torsional vibration of the crankshaft 62. Further, a vibration damper configured to absorb vibration in the bending direction of the crankshaft 62, which is composed of the mass of the damper mass 68 and the spring in the bending direction of the rubber elastic body 70, is configured.

In the above case, the torsion direction spring of the rubber elastic body 70 is determined by the spring strength of the rubber elastic body 70 which is sheared and elastically deformed around the rotation axis of the pulley 66. Further, the bending direction spring of the rubber elastic body 70 is determined by the spring strength of the rubber elastic body 70 which is sheared and deformed in the plane orthogonal to the pulley 66. Therefore, both the torsion direction spring and the bending direction spring are determined by the shape factor of the rubber elastic body 70 in the shearing direction, and in the case of the damper weight changing in the circumferential direction as shown in FIG. It has nothing to do with the generated spring strength of the rubber elastic body 70 in the tensile and compression directions.

Therefore, in the above embodiment, the damper mass 68 is formed into an elliptical shape, and the bending forces in the Y and X directions are changed to thereby bend the crankshaft in the Y and X directions. Vibration can be reduced. In the structure of the damper pulley 66 having the two bending co-oscillation frequencies of the above embodiment, when the damper weight 68 and the elastic body 70 are elliptical as shown in FIGS. The following is the result of an examination of how the resonance frequency changes in the major axis a direction and the minor axis b direction.

Bending direction natural frequency F = 1 / 2π (K / M) ^0.5 Shear spring constant K = G · A _L / α · h where F: Bending direction natural frequency K: Bending direction spring constant (shear spring Constant) M: Mass of damper weight G: Shear elastic coefficient of elastic body A _L Cross-sectional area of elastic body α: τ _max / τ _mean τ _max : Maximum shear stress τ _mean : Average shear stress h: Thickness of elastic body Crank As shown in FIG. 4 of the present embodiment, the shaft damper 64 is
When it has an elliptical shape, α differs in the X and Y directions.

That is, the above α _x and α _{y in} the X and Y directions are as follows.

[0039]

[Equation 1]

Here, a and b represent the major and minor axes of an ellipse of the damper weight 68 and the rubber elastic body 70 having substantially the same shape, and a _{1 is} the inner radius of the major diameter of the damper weight and the elastic body. a ₂ : major radius outer radius of damper weight and elastic body b ₁ : minor radius inner radius of damper weight and elastic body b ₂ : damper radius and minor radius outer radius of elastic body At this time, the above damper weight And the cross-sectional area A of the elastic body
_L becomes as follows.

A _L = π (a ₂ b ₂ −a ₁ b ₁ )

The displacement δ of the damper weight due to shearing when the load W acts on the damper weight in the X or Y direction is given by the following equation.

[0043]

[Equation 2]

Therefore, the shear spring constant K = W / δ = G · A
_L / α · h where α: τ _max / τ _mean τ _max : Maximum shear stress τ _mean : Average shear stress From the above equation, bending natural frequencies F _X and F in the X and Y directions
_Y becomes as follows.

[0045]

(Equation 3)

These frequencies are set to the above G and A._L, M, h are
Under the same condition, the damper weight 68 and the elastic body 70 are
In order to compare with a substantially perfect circle of the same shape, the perfect circle (outer half
Diameter r ₂Inner radius r₁) Bending natural frequency F₀Ask for
And it becomes like the following formula.

[0047]

[Equation 4]

[0048] the above conditions, further provided that equal the width of the damper weights, in addition also _{a 2 -a 1 = b 2 -b} 1 = r 2 -r 1, bending natural frequency of the true annular F ₀ , the relationship between the bending natural frequencies F _X and F _{y in} the X and Y directions of the elliptical ring, F _X / F ₀ , F _Y / F ₀ , and F _X / F _y are respectively expressed by The inner and outer radii r ₂ , r ₁ , the inner and outer radii a _{2 and} a ₁ of the major axis of the elliptic ring and the inner and outer radii b ₂ and b ₁ of the minor axis are obtained as the variables shown in Table 1 below. In the test, almost the same value was obtained.

[0049]

[Table 1]

As is clear from Table 1, as the elliptical annular major axis a of the damper weight 68 increases and the minor axis b decreases, the natural frequency F _x of bending in the X direction gradually increases. The natural frequency of bending in the Y direction is small. Further, as shown in Table 1, the natural frequencies F _x and F _y of bending in the X and Y directions are F
_x > F _y , and the value of F _x / F _y increases as going from Test 1 to Test 5 in Table 1 to 1.08 in Test 1.
It is 1.548, which is about 1.5 times that of 4.

According to the above results, by changing the ellipticity of the damper, the bending natural frequency of the crankshaft and the like in the X and Y directions can be changed to an arbitrary ratio, so that one crankshaft damper 68 can be obtained. Therefore, the bending natural vibrations of the crankshaft 62 in the X and Y directions can be simultaneously reduced. Further, in the above, the shear spring constant was obtained from the deflection due to shearing, and as shown in Table 1, different resonance frequencies could be obtained for the long and short diameters.

Further, in the above embodiment, the damper weight 68 and the elastic body 70 are formed in the same elliptical ring shape, but the damper weight 68 may be formed in a perfect circular ring shape or a non-circular ring shape.
Even if the elastic body 70 is not made to coincide with the elastic body 70, it is possible to obtain substantially the same operational effect as that of the above embodiment. Further, in the above description, the reduction of the bending natural vibrations in the X and Y directions has been described, but the damper mass vibrates greatly near the respective resonance points including the torsional direction of the crankshaft, and the vibration energy of the crankshaft is absorbed. Is what you can do.

In the above embodiment, the case where the invention is applied to the crankshaft of the engine has been described. However, when the invention is applied to the crankshaft of a compressor, a water pump, etc., substantially the same operational effect as the above embodiment can be obtained. You can In the above embodiment, the case of the in-line 4-cylinder engine has been described.
In the case of a V-type 6-cylinder engine, at least the non-circular non-annular or elliptical annular major axis of the elastic body of the damper weight and the elastic body is adjacent to each other in the axial projection view of the crankshaft. The crank arm is arranged along a plane that bisects the angle formed by the crank arm, and the minor axis of the non-annular or elliptical ring is substantially orthogonal to the plane including the axis of the crank and the plane. By arranging along the orthogonal line, it is possible to obtain the same effects as those of the above embodiment.

[0054]

According to the crankshaft damper of the present invention as set forth in claim 1, the rotary body is provided on the crankshaft and rotates integrally with the crankshaft, and the rotary body is provided on a side surface of the rotary body in the crankshaft axial direction. And a damper weight supported by an elastic body, and since the elastic body is formed in a non-circular non-circular shape that is point-symmetric with respect to the crank shaft, the bending of the crank shaft having different resonance frequencies is performed. For two modes of lateral bending, one damper weight can exert the effect as a dynamic damper.

That is, the resonance frequencies of the vertical bending and the horizontal bending of the crank shaft damper are adjusted to the respective resonance frequencies of the vertical bending and the horizontal bending which are generated by the rotation of the crank shaft and are different from each other. If the frequency of the crankshaft approaches the bending frequency in the X and Y directions at the same time, the crankshaft damper can be simply and extremely easily formed by the die-hamic damper of one damper weight. The vibration of the damper mass becomes large, the energy of the vibration of the crankshaft in the X and Y directions is absorbed, the vibration in each direction is reduced, and the noise such as muffled noise in the vehicle compartment can be reduced.

According to the crankshaft damper of the second aspect of the present invention, in the configuration of the first aspect, at least the elastic body of the damper weight and the elastic body is formed in an elliptical ring shape. It is possible to accurately determine the ratio of the length of the elliptic ring-shaped elastic body to the length of the minor axis, and the length of the major axis and the minor axis are adjusted so as to adapt to vibration due to bending in a direction substantially perpendicular to the crank axis. The ratio of can be selected.

Therefore, since it is possible to select the proper radius of the major axis and the minor axis of the elastic body corresponding to the vibration of the lateral bending and the vibration of the longitudinal bending with respect to an arbitrary crankshaft, The vertical bending and horizontal bending vibrations of the crankshaft can be effectively reduced by one damper. According to the crankshaft damper of the third aspect of the present invention, in the configuration of the first or second aspect, at least the elastic body of the damper weight and the elastic body has a non-circular non-circular ring shape or an elliptical ring shape. A major axis is arranged substantially along a straight line connecting the crankshaft axis and the crankshaft pin of the crankshaft, and the non-annular or elliptical annular minor axis is a straight line connecting the crankshaft axis and the crankshaft pin. Since it is arranged along an orthogonal line that is substantially orthogonal to, it is possible to accurately determine the ratio of at least the length of the elastic body of the elliptical annular elastic body and the damper weight, the length of the minor axis, The ratio of the length to the minor axis can be selected so as to be suitable for vibration due to bending in a direction substantially perpendicular to the crank axis.

Therefore, the appropriate radiuses of the long and short diameters of at least the elastic body of the elastic weight and the damper weight corresponding to the vibration of the lateral bending and the vibration of the vertical bending with respect to an arbitrary crankshaft are selected. Therefore, it is possible to effectively reduce the bending vibration of the vertical bending and the horizontal bending of the crankshaft with one damper weight.

Further, since the entire rear surface of the elliptical annular damper weight is firmly supported by the elastic body on the side surface of the rotating body, it effectively resonates with the longitudinal bending and lateral bending vibrations generated by the crankshaft. Then, the vibration can be reduced.
According to the crankshaft damper of the present invention as set forth in claim 4, in the configuration of claim 1 or 2, at least the elastic body of the damper weight and the elastic body has a non-circular non-circular or elliptical ring shape. The major axis is arranged along a plane that bisects the angle formed by the adjacent crank arms in a projection of the crankshaft in the axial direction, and the non-annular or elliptical annular minor axis is the major axis. Since it is arranged along an orthogonal line that is substantially orthogonal to the plane of the crank and the plane including the plane, the damper is effective for the longitudinal bending and transverse bending vibrations generated in the crankshaft even in the V-type engine. Can be resonated with.

According to the crankshaft damper of the present invention as set forth in claim 5, in the structure as set forth in any one of claims 1 to 4, the elastic body is formed of a natural or synthetic resin rubber material. It is possible to effectively resonate with the bending vibration of the crankshaft to reduce the vibration. According to the crankshaft damper of the present invention described in claim 6, in the structure according to any one of claims 1 to 5, the rotating body provided on the crankshaft is a belt pulley, a chain sprocket, and a gear. It is possible to reduce the vibration by resonating with the bending vibration generated in the crankshaft without providing the rotating body in the.

Therefore, the vertical bending vibration and the lateral bending vibration of the crankshaft are reduced, and the power of the crankshaft is transmitted quietly and stably through the belt pulley, the chain sprocket, the gear and the like. You can According to the crankshaft damper of the present invention as set forth in claim 7,
In any one of the configurations 1 to 6, the elastic body and the damper weight are formed in substantially the same shape, and the entire back surface of the damper weight is fixed to the side surface of the rotating body, which is stable. A desired resonance vibration can be generated.

Further, it is possible to accurately determine the ratio of the length of the elliptical annular damper weight to the length of the minor axis, and to adjust to the vibration due to bending in a direction substantially perpendicular to the crank axis, the length, The length ratio of the minor axis can be selected. Therefore, it is possible to select the appropriate radius of the long axis and the short axis of the damper weight corresponding to the vibration of the lateral bending and the vibration of the vertical bending with respect to an arbitrary crankshaft. One of the vibrations of longitudinal bending and lateral bending can be effectively reduced by the damper weight.

Since the rear surface of the elliptical annular damper weight is firmly supported by the side surface of the rotating body by the elastic body, it effectively resonates with the longitudinal bending and lateral bending vibrations generated by the crankshaft. It can act to reduce the vibration.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an embodiment of the present invention.

FIG. 2 is a schematic explanatory view taken along the arrow P of FIG.

FIG. 3 is a schematic view of a single body of the damper weight and the rubber elastic body of FIG.

4A and 4B are schematic diagrams for analyzing the crankshaft damper of FIG. 1, in which FIG. 4A is a front view of the damper, and FIG.
It is sectional drawing which follows the B-4B line.

5A and 5B are schematic explanatory views schematically showing a damper device of a conventional example, in which FIG. 5A is a longitudinal sectional view thereof, and FIG.

6A and 6B are explanatory views of another conventional damper pulley, in which FIG. 6A is a vertical sectional view thereof, and FIG. 6B is a front view of the rubber elastic body of FIG.

7A and 7B show an application example of FIG. 6, in which FIG. 7A is a vertical sectional view thereof, and FIG. 7B is a front view of the rubber elastic body of FIG.

[Explanation of symbols]

 62 crankshaft 64 crankshaft damper 66 damper pulley 68 damper weight 68a side face 68b side face 70 rubber elastic body 70a side face 70b side face 72 belt groove portion 74 hub portion 76 connection portion 78 belt groove portion inner periphery 80 hub portion outer periphery 82 damper mass 84 Inner circumference of 86 Rubber outer circumference of rubber 88 Inner circumference of rubber elastic

Claims (7)

[Claims] 1. An elastic body, comprising: a rotating body provided on a crankshaft and rotating integrally with the crankshaft; and a damper weight supported by an elastic body provided on a side surface of the rotating body in a direction of the crankshaft axis. Is formed in a non-circular annular shape that is point-symmetric with respect to the crank shaft and is not a perfect circle. 2. The crankshaft damper according to claim 1, wherein at least the elastic body of the damper weight and the elastic body is formed in an elliptical ring shape. 3. The non-circular non-circular or elliptical annular major axis of at least the elastic body of the damper weight and the elastic body is substantially a straight line connecting the crank shaft line to the crank shaft pin of the crank shaft. The non-circular or elliptical annular minor axis is arranged along an orthogonal line that is substantially orthogonal to a straight line connecting the crank axis and the crank shaft pin. The crankshaft damper according to claim 1 or 2. 4. The damper weight and the elastic body, at least the non-circular non-circular or elliptical major axis of the elastic body is formed by adjacent crank arms in a projection view of the crank shaft in the axial direction. Arranged along a plane that divides the angle into two substantially equal parts, and the minor axis of the non-circular or elliptical ring is along an orthogonal line that is substantially orthogonal to the axis of the crank and the plane including the plane. The crankshaft damper according to claim 1 or 2, characterized in that 5. The crankshaft damper according to claim 1, wherein the elastic body is made of natural or synthetic resin rubber. 6. The crankshaft damper according to claim 1, wherein the rotating body provided on the crankshaft is a belt pulley, a chain sprocket, or a gear. 7. The elastic body and the damper weight are formed in substantially the same shape.
The crankshaft damper according to any one of 1.