JPH09310736A - Damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the adjustment of ratio of the natural frequency in the radial direction and the twisting direction of a bending vibration damper without providing a stopper for preventing a jump-out of the bending vibration damper by providing a damper for bending vibration and torsional vibration in a space surrounded by a connection part of a pulley hub and a boss part of the pulley hub. SOLUTION: In the case of a conventional second elastic body, which does not have a compressing unit 7B, since width L of a compressing part = 0, spring constant in the radial direction of the compressing unit and spring constant in the twisting direction of the compressing unit are zero. Consequently, in the case where the width L of the conventional compressing unit is zero, natural frequency ωR in the radial direction of this bending vibration damper and the natural frequency ωT in the twisting direction thereof become equal to each other. But in the case of a second elastic body 7, which has a compressing unit 7B, of the damper 11 for bending vibration and torsional vibration, since ωR/ωT>1, ratio of the natural frequency ωR in the radial direction and the natural frequency ωT in the twisting direction of the second elastic body 7 of the damper 11 for bending vibration and torsional vibration can be changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dual mode damper, and more particularly, it effectively absorbs torsional vibration and bending vibration of a rotary shaft such as a crankshaft of a vehicle to effectively absorb vibration in the rotary shaft and engine. The present invention relates to a damper capable of reducing noise caused by this vibration.

[0002]

2. Description of the Related Art Generally, when a rotating shaft such as a crankshaft of an engine rotates, a complicated torque fluctuation is caused on the rotating shaft. Therefore, very complicated vibrations and noises are generated in the rotating shaft and the engine, and in an extreme case, the rotating shaft is broken. The vibrations generated on the rotating shaft such as the crankshaft are mainly two types of vibrations, that is, a torsional vibration and a bending (perpendicular to the shaft) vibration, and various vibrations are generated depending on the supporting state of the rotating shaft and the engine. Indicates the mode.

Therefore, as described in Japanese Patent Publication No. 2-9214, a first damper mass is attached to the outer peripheral side of a pulley hub via a first elastic body for torsional vibration. While absorbing the torsional vibration by using the shear spring force of the second elastic mass, a second damper mass is attached to the cavity of the pulley hub along the axial direction of the shaft through the second elastic body for bending vibration. A dual-mode damper that absorbs bending vibrations by utilizing the shear spring force of the is proposed, and effectively absorbs two vibrations, which are torsional vibrations and bending (perpendicular to the axis) vibrations that occur in the rotating shaft such as the crankshaft. However, the noise caused by the vibration can be reduced.

[0004]

However, in the conventional damper, particularly the dual mode damper, the cavity of the pulley hub has a space for receiving the bolt for mounting the pulley hub on the rotating shaft and the tool for tightening the bolt. And a mounting space for the bending vibration damper composed of the second elastic body and the second damper mass, it is difficult to provide a bending vibration damper of a sufficient size for absorbing the vibration. Is.

Further, since the radial natural frequency and the torsional natural frequency of the bending vibration damper are substantially the same, the damper is generally resonated at both vibration frequencies of bending and torsion generated in the rotating shaft. , Could not absorb the vibration more effectively.

Further, when the second elastic body of the bending vibration damper is broken due to vibration fatigue or the like, there is a risk that the second damper mass will pop out from the cavity of the pulley hub.
Further, in order to prevent the danger that the second damper mass jumps out, it is necessary to separately provide a safety mechanism such as a stopper. Therefore, this safety mechanism must be arranged at or near the cavity of the pulley hub. There was a problem such as not becoming.

Therefore, an object of the present invention is to make the damper for bending vibration relatively large, and further, without providing a stopper for preventing the pop-out, and in addition, for the natural vibration of the damper for bending vibration in the radial direction and the torsional direction. The ratio of numbers can be adjusted.

[0008]

SUMMARY OF THE INVENTION The damper of the present invention comprises:
(A) A boss portion attached to a rotary shaft such as a crankshaft, and (b) a width W located radially outside the boss portion.
1) a pulley hub having a cylindrical portion, the boss portion and a connecting portion connecting the cylindrical portions, and (c) concentrically arranged at a predetermined distance on the outer side in the radial direction of the cylindrical portion of the pulley hub and having an outer periphery. A cylindrical first damper mass having a main body around which a power transmission belt is wound, and (d) a first damper mass interposed between the cylindrical part of the pulley hub and the main body of the first damper mass. Elastic body, (e) a ring-shaped second damper mass concentrically arranged at a predetermined distance on the rotation axis side of the pulley hub connecting portion, and (f) the pulley hub connecting portion and the second damper mass. A second elastic body having an L-shaped cross section, which is interposed between the damper mass and the boss portion of the pulley hub and the second damper mass, is provided, and the first damper mass and the first elastic body are provided. The body acts as a damper for torsional vibration, and the second damper Pamasu and the second elastic body is to operate as a bending vibration and torsional vibration combined damper.

The damper of the present invention comprises (a) a boss portion attached to a rotary shaft such as a crankshaft, and (b) a first cylindrical portion having a width W3 and located radially outside the boss portion,
A second cylindrical portion located on the outer side in the radial direction of the boss portion and having a body portion around which the power transmission belt is wound around the outer peripheral surface, the boss portion, the first cylindrical portion, and the boss portion.
A pulley hub having a connecting portion that connects the cylindrical portions of
(C) A cylindrical first member arranged concentrically with a predetermined distance on the outer side in the radial direction of the first cylindrical portion of this pulley hub.
Damper mass, (d) a first elastic body interposed between the first cylindrical portion of the pulley hub and the first damper mass, and (e) a second cylindrical portion of the pulley hub and a connecting portion. A ring-shaped second damper mass concentrically arranged at a predetermined distance on the rotary shaft side of the coupling portion of the pulley hub in a space surrounded by the boss portion, and (f) the second cylindrical portion of the pulley hub. And a second damper mass, and a second elastic body having an L-shaped cross section, which is interposed between the coupling portion of the pulley hub and the second damper mass. And the first elastic body operate as a damper for torsional vibration,
The second damper mass and the second elastic body operate as a damper for both bending vibration and torsional vibration.

[0010]

1 is a sectional view showing an embodiment of a damper according to the present invention. In the figure, reference numeral 1 is a rotating shaft such as a crankshaft, and a screw hole 1A is provided at one end thereof. Reference numeral 2 denotes a pulley hub. The pulley hub 2 includes a boss portion 2A, a cylindrical portion 2B having a width W1 located radially outside of the boss portion 2A, and a connecting portion 2C connecting the boss portion 2A and the cylindrical portion 2B. There is.

Reference numeral 3 is a cylindrical first damper mass, and the first damper mass 3 is a cylindrical portion 2B of the pulley hub 2.
Of the main body 3A having a width W1 and a width W2 having a power transmission belt (not shown) wound around the outer periphery of the main body 3A and the width W2. , W1> W2). Reference numeral 4 denotes a sleeve, and the sleeve 4 is press-fitted into the cylindrical portion 2B of the pulley hub 2. Reference numeral 5 is a first elastic body, and the first elastic body 5 is interposed between the sleeve 4 and the main body portion 3A of the first damper mass 3 by vulcanization adhesion or the like.

Reference numeral 6 is a ring-shaped second damper mass,
The second damper mass 6 is a space surrounded by the extension portion 3B of the first damper mass 3, the connecting portion 2C of the pulley hub 2 and the boss portion 2A of the pulley hub 2, and rotates the connecting portion 2C of the pulley hub 2. They are arranged concentrically on the shaft side (engine side) with a predetermined distance. 7 is a second L-shaped section
This second elastic body 7 is interposed between the connecting portion 2C of the pulley hub 2 and the second damper mass 6, and the boss portion 2A of the pulley hub 2 and the second damper mass 6 are also provided. Interpose between and.

Reference numeral 8 is a collar, and 9 is a screw.
Is screwed into the screw hole 1A of the rotary shaft 1 via the collar 8 and the pulley hub 2 so that the pulley hub 2 is fixed to the rotary shaft 1
Fixed to. Reference numeral 10 is a torsional vibration damper. The torsional vibration damper 10 is composed of the first damper mass 3 and the first elastic body 5, and 11 is a bending vibration / torsional vibration dual damper. The vibration / torsional vibration dual-purpose damper 11 includes the second damper mass 6 and the second elastic body 7. The damper 11 for both bending and torsional vibrations is provided in a space surrounded by the extension portion 3B of the first damper mass 3, the connecting portion 2C of the pulley hub 2 and the boss portion 2A of the pulley hub 2. is there.

Next, a description will be given of the operation of the damper having the above-mentioned structure, particularly the adjusting function of the ratio of the natural frequency in the radial direction to the natural frequency in the torsional direction of the damper 11 for both bending and torsional vibrations. First, an enlarged view of the second damper mass 6 of the damper 11 for both bending and torsional vibrations and the second elastic body 7 having an L-shaped cross section is shown in FIG. Referring to FIG. 2, the plane perpendicular to the axis of the L-shaped second elastic body 7 is a shearing portion 7A, the spring constant in the radial direction is K _SR , and the spring constant in the torsional direction is K _ST .
Similarly, the plane parallel to the axis of the L-shaped second elastic body 7 is the compression portion 7B, the spring constant in the radial direction is K _CR , and the spring constant in the torsion direction is K _CT . If the mass of the second damper mass 6 is M and the moment of inertia is I, the radial natural frequency ω _R and the torsional natural frequency ω _T of the bending / torsion vibration dual damper 11 are as follows. .

[0015]

[Equation 1]

Here, the radial direction spring constant K of the shearing portion 7A
_SR , the radial spring constant K _{CR of} the compression part 7B, the torsional spring constant K _{ST of} the shearing part 7A, the torsional spring constant K _CT of the compression part 7B, the mass M of the second damper mass 6, the second damper mass 6 The moment of inertia I is as follows, respectively.

[0017]

[Equation 2]

Here, R ₁ is the outer radius of the second damper mass 6, the outer radius of the shearing portion 7A of the L-shaped second elastic body 7, and R ₂ is the inner radius of the second damper mass 6. It is the inner radius of the shearing portion 7A of the L-shaped second elastic body 7 and the outer radius of the compression portion 7B of the L-shaped second elastic body 7. R ₃ is the inner radius of the compression portion 7B of the L-shaped second elastic body 7, and t is L
The width of the shearing portion 7A of the second elastic body 7 having a character shape, L is the width of the compression portion 7B of the second elastic material 7 having an L shape, W is the width of the second damper mass 6, and G is the second shape of the L shape. Shear elastic coefficient of the elastic body 7, ρ is the specific gravity of the second damper mass 6, and E is the L-shaped second
The Young's modulus and the shape rate of the elastic body 7 are as follows. However, S is a shape ratio and is a positive value.

[0019]

(Equation 3)

Here, the second compression mechanism 7B is not provided.
In the case of the elastic body of, the width L of the compression portion is L = 0, the spring constant K _{CR of} the compression portion is K _CR = 0, and the torsion spring constant K of the compression portion is
_CT = 0. Therefore, the radial natural frequency ω _R and the torsional natural frequency ω _T of the conventional bending vibration damper are as follows.

[0021]

(Equation 4)

From this equation 4, ω _R / ω _T = 1 and in the case of the second elastic body which does not have the conventional compression section, in other words, when the width L of the compression section is zero, this bending vibration is generated. Natural frequency ω _R and torsional natural frequency ω of the damper for vehicle
Is equal to _T.

Further, in the case of the second elastic body 7 having the compression portion 7B of the damper 11 for both bending and torsional vibrations according to the present invention, it is as follows.

[0024]

(Equation 5)

From this equation 5, it is possible to change the ratio of the natural frequency ω _{R in} the radial direction and the natural frequency ω _{T in} the torsion direction of the second elastic body 7 of the damper 11 for both bending and torsional vibrations according to the present invention. That is,

[0026]

(Equation 6)

Here, since m = R ₁ / R ₂ , m>
Since 1 n = R ₂ / R ₃ , n> 1.

Therefore, if the value E relating to the Young's modulus and the shape factor of the L-shaped second elastic body 7 is E ≧ 2, (K
_CR / M) / (K _CT / I)> 1.

By the way, E = 5 + 3.29S ² where S is a shape ratio and is a positive value, and S = L / 2 (R
Represented by ₂ -R _3). By, E> 5 and ω _R
The value of / ω _T can be adjusted to 1 or more depending on the size of L.

In the above description, the first damper mass 3 of the damper 10 for torsional vibration is composed of the main body portion 3A having the width W1 and the extension portion 3B having the width W2, but the present invention is not limited to this. Of course, the extension 3B is not necessary when the desired mass is obtained by itself.

FIG. 3 is a sectional view showing another embodiment of the damper according to the present invention. In the figure, reference numeral 20 denotes a pulley hub, and this pulley hub 20 includes a boss portion 20A attached to the rotary shaft 1 such as a crankshaft
Of the first cylindrical portion 20B having a width W3 located radially outward of the
And a body portion 2 having a width W4 which is located on the outer side of the boss portion 20A in the radial direction and around which the power transmission belt is wound around the outer peripheral surface.
0C and width W5 (however, W4> W5)
Second cylindrical portion 20E having an extended portion 20D, the boss portion 20A, the first cylindrical portion 20B, and the connecting portion 20F that connects the boss portion 20A and the second cylindrical portion 20E.
And

Reference numeral 21 is a sleeve, and this sleeve 21
Is press-fitted into the cylindrical portion 20B of the pulley hub 20. 22
Is a cylindrical first damper mass, and the first damper mass 22 is concentrically arranged at a predetermined distance on the outer side in the radial direction of the first cylindrical portion 20B of the pulley hub 20.
A power transmission belt (not shown) is wound around the outer peripheral surface. Reference numeral 23 is a first elastic body, and the first elastic body 23 includes the sleeve 21 and the first damper mass 2 described above.
It is interposed by vulcanization adhesion or the like.

Reference numeral 24 is a ring-shaped second damper mass, and the second damper mass 24 is the main body portion 20C of the second cylindrical portion 20E of the pulley hub 20 and the pulley hub 2.
0 connecting portion 20F, the pulley hub 20 and the boss portion 20A
In the space surrounded by and, the connecting portion 20 of the pulley hub 20
They are arranged concentrically on the rotating shaft side (engine side) of F with a predetermined distance. Reference numeral 25 denotes a second elastic body having an L-shaped cross section, and the second elastic body 25 is the second elastic body of the pulley hub 20.
In the space surrounded by the body portion 20C of the cylindrical portion 20E, the connecting portion 20F of the pulley hub 20 and the second damper mass 24, the body portion 20C of the second cylindrical portion 20E of the pulley hub 20 and the second It is interposed between the damper mass 24 and the coupling portion 20F of the pulley hub 20 and the second damper mass 24.

Reference numeral 26 is a torsional vibration damper. The torsional vibration damper 26 is composed of the first damper mass 22 and the first elastic body 23, and 27 is a bending vibration / torsional vibration damper. The bending / torsion vibration dual-purpose damper 27 is composed of the second damper mass 24 and the second elastic body 25. Further, the bending vibration / torsional vibration dual damper 27 is used for the second cylindrical portion 2 of the pulley hub 20.
The connecting portion 20 between the main body portion 20C of 0E and the pulley hub 20
It is provided in a space surrounded by F and the second damper mass 24. The pulley hub 20 can be fixed to the rotary shaft 1 by screwing a screw 9 into the screw hole 1A of the rotary shaft 1 via the collar 8.

Next, the operation of the damper having the above-described structure, particularly the function of adjusting the ratio of the natural frequency in the radial direction to the natural frequency in the torsional direction of the damper 27 for both bending and torsional vibrations will be described with reference to FIGS. Of course, you can do the same as you did. Further, in the above description, the main body 2 of the pulley hub 20
The width W4 is 0C and the width W5 is the extension 20D, but it is not limited to this. In particular, the width of the main body portion 20C of the pulley hub 20 can be arbitrarily set by the length L of the compression portion of the second elastic body 25 having the L-shaped cross section of the bending / torsion vibration damper 27. is there. Further, it goes without saying that the width W5 of the extension 20D may be zero (0).

[0036]

As described in detail above, according to the damper of the present invention, the torsional vibration generated in the crankshaft of the internal combustion engine causes the first damper masses 3, 22 of the torsional vibration dampers 10, 26. And the natural frequency adjusted from the torsional spring force of the first elastic bodies 5 and 23, and the second damper masses 6 and 24 of the dampers 11 and 27 for both bending and torsional vibrations.
And the natural frequency adjusted by the torsional spring force of the second elastic bodies 7 and 25 having an L-shaped cross section, the vibration absorption capacity can be absorbed more than before. Can be improved.

The bending vibration generated in the crankshaft of the internal combustion engine is the same as the bending vibration / torsional vibration dampers 11 and 2.
By resonating at the natural frequency adjusted from the combined spring force of the radial shear spring force and the compression spring force of the second damper masses 6 and 24 of 7 and the second elastic bodies 7 and 25 having an L-shaped cross section. Can be absorbed. Here, in particular, since the dampers 11 and 27 for both bending and torsional vibrations can secure the outer diameter dimension without being restricted by the presence of the cylindrical portions 2B and 20B of the pulley hubs 2 and 20, as compared with the conventional dampers, a relatively large mass can be obtained. The second damper masses 6 and 24 can be provided, and the vibration energy can be more effectively absorbed.

Further, when the dampers 10 and 26 for torsional vibration have insufficient absorption capacity, the dampers 11 and 27 for both bending and torsional vibrations can be positively operated to absorb the torsional vibrations. .

These matters will be further described with reference to FIG. FIG. 4 is a diagram comparing the torsional vibration characteristics when the vertical axis represents the amplitude (VW) and the horizontal axis represents the rotational speed (RN). In this case, the characteristic curve G1 (shown by a solid line) has no damper, the characteristic curve G2 (shown by a dotted line) has only the conventional torsional vibration damper, and the characteristic curve G3 (shown by a one-dot chain line) shows the bending of the present invention. This is the characteristic when a damper for vibration / torsional vibration is positively used. Further, in consideration of the life due to vibration fatigue of the bending vibration / torsion vibration dampers 11 and 27, by changing the L dimension of the second elastic bodies 7 and 25 so that the dampers 11 and 27 operate only for bending vibration absorption. The ratio between the natural frequency of torsion and the natural frequency of bending can be adjusted.

Even if the second elastic bodies 7 and 25 are broken due to vibration fatigue due to absorption of vibration energy,
The second damper masses 6, 24 are between the pulley hubs 2, 20 and the engine (not shown), and
Since the inner diameter of 4 is set to be smaller than the maximum diameter of the pulley hubs 2 and 20, there is no danger of jumping forward, and there is an effect that a special stopper need not be provided.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a damper according to the present invention.

FIG. 2 is a partially detailed cross-sectional view of FIG.

FIG. 3 is a sectional view showing another embodiment of the damper according to the present invention.

FIG. 4 is a diagram comparing torsional vibration characteristics.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotary shaft 2,20 pulley hub 3,22 first damper mass 4 sleeve 5,23 first elastic body 6,24 second damper mass 7,25 second elastic body 10,26 torsional vibration damper 11,27 bending Vibration / Torsion Vibration Dual Damper 21 Sleeve

Claims (2)

[Claims] 1. A pulley hub having a boss portion attached to a rotary shaft such as a crankshaft, a cylindrical portion having a width W1 located radially outside of the boss portion, and a connecting portion connecting the boss portion and the cylindrical portion. And a cylindrical first damper mass, which is concentrically arranged at a predetermined distance on the outer side in the radial direction of the cylindrical portion of the pulley hub, and has a main body portion around which a power transmission belt is wound around the outer peripheral surface, A first elastic body interposed between the cylindrical portion of the pulley hub and the main body of the first damper mass, and a ring concentrically arranged on the rotation shaft side of the connecting portion of the pulley hub at a predetermined distance. -Shaped second damper mass, and a second L-shaped section which is interposed between the connecting portion of the pulley hub and the second damper mass and between the boss portion of the pulley hub and the second damper mass. And an elastic body of The first damper mass and the first elastic body operate as a torsional vibration damper, and the second damper mass and the second elastic body operate as a bending vibration / torsional vibration combined damper, and the bending vibration / torsional vibration The vibration / damper is provided in a space surrounded by the connecting portion of the pulley hub and the boss portion of the pulley hub. 2. A boss portion attached to a rotating shaft such as a crankshaft, a first cylindrical portion having a width W3 located radially outside of the boss portion, and a radially outer portion of the boss portion, and an outer periphery thereof. A pulley hub having a second cylindrical portion having a body portion around which a power transmission belt is wound, a boss portion, the first cylindrical portion, and a connecting portion connecting the boss portion and the second cylindrical portion; A cylindrical first damper mass, which is concentrically arranged at a predetermined distance outside the first cylindrical portion of the pulley hub, and a first cylindrical portion of the pulley hub and the first damper mass. In a space surrounded by the first elastic body interposed between the second cylindrical portion, the connecting portion, and the boss portion of the pulley hub, the pulley hub is concentric with a predetermined distance on the rotating shaft side of the connecting portion of the pulley hub. The second ring-shaped damper masses that are arranged in a A second elastic body having an L-shaped cross section, which is interposed between the second cylindrical portion of the pulley hub and the second damper mass and is interposed between the coupling portion of the pulley hub and the second damper mass. The first damper mass and the first elastic body operate as a torsional vibration damper, and the second damper mass and the second elastic body operate as a bending vibration / torsional vibration combined damper. The damper for both bending and torsional vibration is provided in a space surrounded by the second cylindrical portion of the pulley hub, the connecting portion of the pulley hub, and the boss portion of the pulley hub.