JP2000274489A - Dynamic damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dynamic damper simple in structure, preventing the increase in weight, high in reliability on a vibration reduction effect, and besides effective to reduction of vibration of a highest degree. SOLUTION: The inner surface on the outer peripheral side of a containing chamber 13 formed at a phase distance of 90 deg. at a hub 1 forms a cylindrical recessed surface 13a, passing a circumference C13 with a radius R13 and having a center being the axis center O1 of the hub 1 and having a line P13 paralleling an axis center O2 and forming a curvature center. A rolling mass 3 is contained in each containing chamber 13. The rolling mass 3 is moved in a containing chamber 13 toward the outer peripheral side during rotation of the hub 1, and reciprocated like a pendulum as it is rolled in the cylindrical recessed surface 13a with a behavior radius Δr equivalent to a difference between the radius r3 of the rolling mass 3 and the radius r13 of the containing chamber 13. By properly setting R13/Δr, n-degree twist vibration is effectively reduced at all the numbers of revolutions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic damper used as a means for absorbing torsional vibration and torque fluctuation generated on a rotating shaft such as an engine crankshaft.

[0002]

2. Description of the Related Art An engine of an automobile or the like is driven while repeating intake, compression, explosion (expansion) and exhaust strokes, and reciprocating motion of a piston is converted into rotary motion by a crankshaft. Torsional vibration (vibration in the direction of rotation) is generated in the crankshaft as it rotates. A dynamic damper is attached to the end of the crankshaft in order to prevent the occurrence of troubles due to the increase of the torsional vibration. Typical examples thereof include a torsional damper and a centrifugal pendulum type dynamic damper. It has been known.

[0003] Of these, the former torsional damper is:
For example, an annular mass body is arranged via rubber on the outer periphery of a hub attached to a crankshaft, and has a constant natural frequency in the torsional direction determined by the rubber spring constant and the inertial mass of the mass body. By dynamic vibration absorption effect,
This is to reduce torsional vibration in a specific rotation speed range. On the other hand, the centrifugal pendulum type dynamic damper
As will be described later, a vibration absorbing mechanism using a centrifugal pendulum whose frequency changes according to the number of rotations is provided.

Conventionally, a dynamic damper of a centrifugal pendulum type basically has an inner peripheral boss 101 as shown in FIG.
a is a disk-shaped hub 101 attached to a crankshaft (not shown) to be subjected to vibration absorption and having a pulley 101b formed on the outer periphery.
And a plurality of pins 102 arranged at equal intervals on a circumference C of a predetermined radius R from the axis of the hub 101, and a centrifugal pendulum 1 rotatably attached to each of the pins 102.
03 is provided. And according to this configuration,
When the torsional vibration of the crankshaft is input to the hub 101, each centrifugal pendulum 103 makes the center O of the hub 101 (crankshaft) and the center P of the pin 102 center on the pin 102.
And the direction of the torque due to the swing is opposite to the torque of the torsional vibration, thereby obtaining a damping force.

This will be described in more detail. In this kind of centrifugal pendulum type dynamic damper, a centrifugal pendulum 1
03 and the axis P of the pin 102 which is the center of its swing.
, And the angular velocity of the hub 101 is ω, the natural frequency f of the centrifugal pendulum 103 is
by e includes: the behavior radius r, and place Aruomega ² of the centrifugal force that depends on the angular velocity omega,

(Equation 1) And changes in proportion to the rotation speed (angular velocity ω). In order to reduce the torsional vibration of the n-order component during rotation,
R and r are

(Equation 2) It is effective to set them so that Therefore,
According to this type of dynamic damper, by setting R / r appropriately, the natural frequency fe of the centrifugal pendulum 103 can be adjusted to the n-th frequency, for example, the torsional secondary component in the rotation of a 4-cylinder 4-cycle engine. Since it changes so as to be always equal to the vibration frequency, the secondary torsional vibration can be effectively reduced at any rotational speed.

[0006]

However, in the above-mentioned conventional centrifugal pendulum type dynamic damper,
Pin 10 for rotatably supporting centrifugal pendulum 103
2 and a bearing (not shown) are indispensable, which not only complicates the structure but also increases the manufacturing cost and has a problem in reliability.

In order to effectively reduce high-order vibrations by using this kind of dynamic damper, it is necessary to increase R / r from the above equation (2).
02, the radius of rotation R of the axis P of the shaft 02 must be increased, and the radius of movement r of the centrifugal pendulum 103 must be as small as possible. Must. However, the pin 102
Of the turning radius R of the hub 101 (the pulley 101b)
And the pin receives the centrifugal force acting on the centrifugal pendulum 103 with the pin 102,
In terms of strength, the pin 102 cannot be made very thin, and there is a limit to reducing the behavior radius r. For this reason, in the related art, it has been difficult to manufacture a dynamic damper effective for reducing vibration of a high order.
In addition, if a large number of centrifugal pendulums 103 are attached to the hub 101 to increase the vibration absorbing capacity, the weight of the entire dynamic damper increases, which may cause a problem in handling and mounting.

The present invention has been made in view of the above problems, and its main technical problems are that the structure is simple, the weight does not increase, and the reliability of the vibration reduction effect is low. An object of the present invention is to make it possible to manufacture a dynamic damper that is high and that is effective in reducing vibration of a high order.

[0009]

The above-mentioned conventional technical problems can be effectively solved by the present invention. That is, the dynamic damper according to the present invention, the rotating disk provided concentrically with the rotating shaft of the vibration absorption target, at least a surface facing the inner peripheral side of the rotating disk is centered on a line parallel to the axis of the rotating disk. A plurality of accommodation chambers each having a cylindrical concave surface are provided at predetermined intervals in the circumferential direction, and the rolling masses are accommodated in the respective accommodation chambers so as to be rollable. In this configuration, the rolling mass reciprocates while rolling on the cylindrical concave surface in the storage chamber under the centrifugal force, thereby having a vibration absorbing function similar to that of the conventional centrifugal pendulum type dynamic damper. It does not require a pin support structure.

[0010] Further, as a more preferable means added in the above configuration, each accommodating chamber and the rolling mass accommodated in the accommodating chamber have a radius from the axis of the hub to the center of curvature of the cylindrical concave surface of the accommodating chamber. A plurality of types of combinations are set, which have different ratios from the radius of movement of the center of gravity of the rolling mass rolling along the cylindrical concave surface. Thereby, torsional vibrations of different orders can be absorbed.

[0011]

FIG. 1 schematically shows a first preferred embodiment of a dynamic damper according to the present invention. The dynamic damper according to this embodiment reduces torsional vibration of a crankshaft of an engine mounted on an automobile or the like, for example.
A hub as a rotating disk attached to a shaft end (one end or both ends) of the crankshaft. A pulley portion 12 on which a V-belt (not shown) for transmitting rotation of a crankshaft to a rotation shaft of an auxiliary device such as an alternator is formed on an outer peripheral portion of the hub 1.

On the inner peripheral side of the pulley portion 12 of the hub 1, four housing chambers 13 are recessed from one surface at a phase interval of 90 °. Each accommodation chamber 13 is formed in the circumferential C ₁₃ as the axis O ₁ and parallel to the line P ₁₃ the radius R ₁₃ about the axis O ₁ of the hub 1 to the cylindrical surface of the center of curvature The open ends of the bosses 11 are closed by covers 2 made of a metal plate fitted to the outer peripheral surface of one end of the boss 11, respectively.

As shown in FIG. 3, the housing chamber 13 is formed by penetrating the hub 1 in the axial direction, and is formed by two covers 2A and 2B fitted to the outer peripheral surfaces of both ends of the boss portion 11.
The structure may be closed from both sides in the axial direction.

In each of the storage chambers 13, a rolling mass 3 is provided.
Is housed. The rolling mass 3 is, for example, as shown in FIG.
It has a cylindrical shape as shown in (A), a cylindrical shape as shown in (B), or a spherical shape as shown in (C), and its radius r ₃ is the radius r of the accommodation chamber 13. ₁₃
It is smaller than that. Therefore, the rolling mass 3 is generated by the centrifugal force during rotation of the hub 1 due to centrifugal force.
When the torsion vibration from the crankshaft is input to the hub 1 and the torsion vibration is input to the hub 1, the line Q passing through the axis O ₁ of the hub ₁ and the center P _{13 of the} housing chamber 13 is moved. _The roller 1 rolls on the cylindrical concave surface 13a facing the inner peripheral side of the hub 1 on the inner surface of the housing chamber 13 so as to reciprocate on both sides of the housing 1.

More specifically, the cylindrical concave surface 1 of the accommodation chamber 13
The radius of the trajectory of the center of gravity G ₃ rolling mass 3 are rolling on the 3a (behavior radius) [Delta] r is the radius of the receiving chamber 13 and the radius r ₃ of the rolling mass 3 (radius of curvature of the cylindrical concave surface 13a) corresponding to the difference between r _13. That is, when torsional vibration is input to the hub 1 rotating with the crankshaft, the rolling mass 3
The cylinder ₁₃ reciprocates like a pendulum while rolling with a behavior radius Δr around the center of curvature P13 of the cylindrical concave surface 13a corresponding to the center of the storage chamber 13.

Here, assuming that the angular velocity of the hub 1 is ω, when the rolling mass 3 has a cylindrical roller shape, the frequency fe of the reciprocating behavior is the behavior radius Δr and the centrifugal force dependent on the angular velocity ω. By the force field and the inertial mass of the rolling mass 3,

(Equation 3) And changes in proportion to the rotation speed (angular velocity ω). In order to reduce the torsional vibration of the n-order component during rotation,
R ₁₃ and Δr are:

(Equation 4) It is effective to set them so that

[0017] That is, by setting the R ₁₃ and Δr properly, the frequency fe of the reciprocating behavior of rolling mass 3 is always the same and become a frequency of the torsional vibration of the n-th order in the rotation of the engine (e.g., second order) In addition, the reciprocating behavior is performed with a predetermined phase difference from the input torsional vibration, thereby generating a torque in a vibration damping direction. Therefore, the n-order vibration can be effectively reduced at any rotational speed.

[0018] According to the above configuration, the r ₁₃ (the radius of curvature of the cylindrical concave surface 13a) radius of r ₃ and the accommodating chamber 13 of the rolling mass 3, significantly reduced the behavior radius Δr of the rolling mass 3 Therefore, by increasing the value of n, it is possible to obtain a dynamic damper effective for reducing high-order torsional vibration. Moreover, since the radius r ₃ of the rolling mass 3 by decreasing the behavior radius Δr does not that inevitably small, it is possible to improve the vibration absorbing property gives the required mass rolling mass 3.

Further, since a support structure using pins and bearings, such as the conventional centrifugal pendulum type dynamic damper shown in FIG. 6, is not required, the structure is simple. In addition, when a large number of vibration absorbing systems using the rolling mass 3 are provided, the number of the accommodation chambers 13 formed in the hub 1 is also increased, so that the weight does not increase.

The arrangement of the storage chambers 13 may be any positional relationship that does not cause an imbalance in the center of gravity of the hub 1, and is not limited to a 90 ° phase interval as in the first embodiment. .

[0021] Incidentally, when the torsional direction natural frequency of the crankshaft is f _t, n order of the torsional vibration in the crankshaft, torsional angle when the rotational speed f _{t /} n is known that the maximum ing. That is, for example, the peak appears in the fourth order of the torsional vibration when speed is f _{t /} 4 is relatively slow, the peak of the second order torsional vibration appear at the time of f _{t /} 2 is faster than that. Therefore, in the dynamic damper having the above configuration, the storage chamber 13 and the rolling mass 3
It is more preferable to set a plurality of different combinations of n values in equation (4) to reduce torsional vibrations of a plurality of orders.

FIG. 4 shows a second embodiment of the present invention as an example. That is, in this dynamic damper, four accommodation chambers 13 provided in the phase interval of 90 °, all the center P ₁₃ is in the upper hub 1 and the concentric circle C _13, and the same radius r ₁₃ each other In contrast, the storage chambers 13 and
Rolling masses 3A, 3A in the storage chamber 13 and storage chambers 13, 13 which are 90 ° out of phase and 180 ° symmetric to each other
Rolling mass 3B of the inner, 3B may radius _{r 3} are different from each other. Therefore, relatively radius r ₃ small rolling mass 3
A because its behavior radius Δr increases, (4) the value of n is decreased in type, large rolling mass 3B relatively radius r _3, since its behavior radius Δr is reduced,
The value of n increases.

The construction of the other parts is basically similar to that of the first embodiment described above.

Therefore, according to the second embodiment,
The rolling mass 3A always behaves in the opposite direction to the input vibration at the same frequency as, for example, the secondary vibration of the crankshaft, thereby effectively reducing the secondary vibration at any rotational speed. System. . Similarly, the rolling mass 3B can be a dynamic vibration absorbing system that effectively reduces, for example, the fourth-order torsional vibration at any rotational speed. Therefore, in this case, the rotational speed of the crankshaft is _ft
/ 4, the peak of the torsion angle due to the quaternary vibration is significantly reduced, and when _ft / 2, which is a higher rotation range, is reached, the peak of the torsion angle due to the secondary vibration is significantly reduced. .

[0025] Note that the second embodiment other configurations, such as in the form, for example containing chamber 13 of the cylindrical concave surface 13a of radius of curvature r ₁₃ behavior of rolling mass 3 by varying the radius Δr
Are different from each other, or the axis O of the hub 1 is
_The center of curvature P ₁₃ of the cylindrical concave surface 13a about ₁
By making the radius _{R 13} different from the rotation locus of (circumference _{C 13),} by setting a plurality of types of different combinations of _{R 13} / [Delta] r, rolling mass 3A, the 3B, torsional vibration of the different orders Can be reduced. In the second embodiment, R ₁₃ / Δ
Although two kinds of combinations of the accommodating chambers 13 and the rolling masses 3 having different r are used, three or more kinds may be used to reduce the torsional vibration of three or more orders.

Next, FIG. 5 schematically shows a third preferred embodiment of the dynamic damper according to the present invention.
In this embodiment, the accommodation chambers 13 formed in the hub 1 at 90 ° phase intervals form a long hole. That the accommodating chamber 13, and a cylindrical convex surface 13b of the cylindrical concave surface 13a and the inner side of the outer peripheral side, the curvature center P _13, the radius R ₁₃ about the axis O ₁ of the hub 1 on the circumference _{C 13,} 9
They are located at a phase interval of 0 °.

The configuration of the other parts is basically similar to that of the first embodiment described above.

Therefore, according to the third embodiment,
When the hub 1 rotates, the rolling mass 3 comes into contact with the cylindrical concave surface 13a on the outer peripheral side in the storage chamber 13 due to the centrifugal force,
By the torsional vibration of the crank shaft is input to the hub 1, so as to reciprocate the both sides of the line Q ₁ passing through the curvature center P ₁₃ of axis O ₁ and the cylindrical concave surface 13a of the hub 1, the cylindrical It rolls on the concave surface 13a. The behavior radius Δr of the center of gravity G ₃ of the rolling mass 3 at this time is equivalent to the difference between the radius r ₃ and the radius of curvature r ₁₃ of the cylindrical concave surface 13a. Therefore, by appropriately setting R ₁₃ / Δr, as in the first embodiment, the n-th torsional vibration can be effectively reduced at any rotational speed.

The present invention is not limited by the illustrated embodiment. For example, the accommodation chamber 13 has different R ₁₃ / Δ by alternately arranging the circular one shown in FIG. 1 and the elongated one shown in FIG. 5 in the circumferential direction.
r can also be set.

[0030]

According to the dynamic damper according to the present invention, the rolling mass moves in a pendulum while rolling on the cylindrical concave surface in the accommodating chamber. Since it has a function, it does not require a support structure with pins. As a result, the structure can be simplified, the manufacturing can be facilitated, and the device can be made cheap and highly reliable. In addition, since the behavior radius of the rolling mass corresponding to the difference between the radius of curvature of the cylindrical concave surface and the radius of the rolling mass can be significantly reduced, a structure capable of reducing high-order torsional vibration can be obtained.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams showing a first embodiment of a dynamic damper according to the present invention, wherein FIG. 1A is a front view, and FIG.
-O ₁ is a cross-sectional view.

FIG. 2 is a perspective view showing an example of the shape of a rolling mass in the embodiment.

FIG. 3 is a half sectional view showing another closed structure of the mass storage chamber in the embodiment.

FIG. 4 is a front view showing a second embodiment of the dynamic damper according to the present invention.

FIGS. 5A and 5B are diagrams showing a third embodiment of the dynamic damper according to the present invention, wherein FIG. 5A is a front view, and FIG.
-O ₁ is a cross-sectional view.

FIG. 6 is a front view schematically showing an example of a conventional centrifugal pendulum type dynamic damper.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hub (rotary disk) 11 Boss part 12 Pulley part 13 Storage room 13a Cylindrical concave surface 2, 2A, 2B Cover 3 Rolling mass

Claims (2)

[Claims] 1. A rotating disk (1) provided concentrically with a rotating shaft to be subjected to vibration absorption, at least a surface facing an inner peripheral side of the rotating disk (1) is parallel to an axis of the rotating disk (1). a line of curvature center (P ₁₃₎ and a plurality of storage chambers having a cylindrical concave surface (13a) to (13) is provided at a predetermined circumferential interval, rolling mass (3 to each housing chamber (13) ) Are accommodated in a rollable state. 2. The housing chamber (13) and the rolling mass (3) housed in the housing chamber (13) move from the axis (O) of the turntable (1) to the cylindrical concave surface (13a) of the housing chamber (13). Center of curvature (P
₁₃₎ until the radius _{(R 13),} the cylindrical concave surface (13
A plurality of combinations having different ratios (R ₁₃ / Δr) from the radius of movement (Δr) of the center of gravity (G ₃ ) of the rolling mass (3) rolling along a) are set. The dynamic damper according to claim 1, wherein