JP2000213600A - Centrifugal pendulum vibration absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal pendulum vibration absorber capable of effectively reducing torsional-vibration of a different order generated with rotation of a crankshaft. SOLUTION: On a disc 10 concentrically provided on a crankshaft 2, eccentric masses 11 to 13 are rotatably provided through supporting pins 11a to 13a disposed on circumferences C11 to C13 having different radiuses R11 to R13 respectively. Each of the eccentric masses 11 to 13 can absorb torsional-vibration of plural orders having different rotating speed range where a torsional angle reaches its peak, by a ratio of the radiuses R11 to R13 to the eccentric distance L11 to L13 between the supporting pins 11a to 13a and the centers of gravity G11 to G13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration absorbing technique which is used as a damper for absorbing torsional vibration and torque fluctuation generated on a rotating shaft such as an engine crankshaft, and particularly utilizing a centrifugal pendulum.

[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. In order to prevent the occurrence of problems due to such an increase in torsional vibration, vibration absorbing means is attached to the shaft end of the crankshaft, and typical examples thereof include a torsional damper and a centrifugal pendulum type vibration absorber. 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 circumference of a hub attached to a crankshaft, and has a specific natural frequency in the torsional direction due to the spring constant of rubber and the inertial mass of the mass body. The purpose of this invention is to reduce torsional vibration in a specific rotation speed range by a dynamic vibration absorption effect. On the other hand, the centrifugal pendulum type vibration absorber is provided with a vibration absorbing mechanism using a pendulum whose natural frequency changes according to the rotation speed, as described later.

Conventionally, as shown in FIG. 3, a centrifugal pendulum type vibration absorber basically includes a disk 101 provided concentrically on a crankshaft 100 to be subjected to vibration absorption, and a disk 101
A plurality of pins 102 are disposed at equal intervals on a circumference C having a predetermined radius R from the axis thereof, and an eccentric mass 103 rotatably attached to each of the pins 102. According to this configuration, when the torsional vibration of the crankshaft 100 is input to the disk 101, each eccentric mass 1
03 swings around the pin 102 to both sides of a line a passing through the pin 102 and the axis of the crankshaft 100, thereby absorbing the energy of the torsional vibration.

In this type of centrifugal pendulum type vibration absorber, the center of gravity G of the eccentric mass 103 and the pin
Let L be the distance to the axis of the eccentric mass (hereinafter referred to as the eccentric distance) and ω be the angular velocity of the disk 101. The natural frequency fe of the eccentric mass 103 can be calculated by the following formula. by a place Rω ² of force,

(Equation 1) And changes according to the rotation speed (angular velocity ω). That is, by appropriately setting R and L, the natural frequency fe of the eccentric mass 103 can be changed to a specific rotational order frequency,
For example, the frequency of the torsional vibration of the secondary component in the rotation of the four-cylinder four-cycle engine is always made equal, and the secondary torsional vibration can be effectively reduced at any rotational speed.

[0006]

Here, the crankshaft 1
If the torsional direction natural frequency of 00 is f _t, n order of the torsional vibration in the crankshaft 100, a crank shaft 1
It is known that the rotation speed of 00 becomes maximum when the rotation speed is _ft / n. That is, as shown by a solid line in the diagram in FIG.
Is maximum when the rotation speed is f _t / 4, and 6
The torsional angle of the crankshaft 100 due to the next torsional vibration becomes maximum when the rotation speed is _ft / 6.

According to the above conventional centrifugal pendulum type vibration absorber,
As shown by the broken line in FIG. 4, for example, when the rotation speed is f _t / 2
The torsional vibration having the maximum amplitude can be effectively reduced at the time, but the effect of reducing torsional vibrations of other orders cannot be obtained. Therefore, when the engine speed is f _t / 4, the fourth order torsional vibration is reduced. Caused a large torsional angular displacement on the crankshaft 100 due to the torsional vibration, and a large torsional angular displacement due to the sixth-order torsional vibration when the rotational speed was _ft / 6.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a main technical problem thereof is that a centrifugal pendulum-type vibration absorber capable of effectively reducing torsional vibrations of different orders is provided. To provide equipment.

[0009]

As a means for effectively solving the above-mentioned conventional technical problems, a centrifugal pendulum type vibration absorber according to the present invention comprises a rotating disk provided concentrically on a rotating shaft to be subjected to vibration absorption. And an eccentric mass rotatably arranged on the rotating disk via a spindle. The eccentric mass includes a rotating radius R of the spindle around the axis of the rotating disk, and an axis of each of the spindles. A plurality of sets having different ratios R / L to the eccentric distance L from the center to the center of gravity of the eccentric mass are arranged. In this case, the ratio R / L is
Different values can be set by making one or both of R and L different from each other. Further, in order to reduce the torsional vibration of the n-order component, the above R and L
To

(Equation 2) Therefore, the radius R and the eccentric distance L of the rotation trajectory of the support shaft in each set of eccentric masses are set so that the square roots of R / L are different from each other. By doing so, it is possible to absorb torsional vibrations of a plurality of orders having different rotational speed ranges where the torsion angle peaks.

[0010]

FIG. 1 schematically shows a preferred embodiment of a centrifugal pendulum type vibration absorber according to the present invention. The centrifugal pendulum type vibration absorber 1 according to this embodiment reduces torsional vibration of a crankshaft 2 of an engine mounted on an automobile or the like, that is, a flywheel (one or both ends) of the shaft end of the crankshaft 2. (Not shown)), and three sets of eccentrics which are arranged on the circumference of the disk 10 having different radii and on different phases of the disk 10 and are each formed of a metal plate or the like having an appropriate mass. Masses 11 to 13 are provided.

The eccentric mass 11 has a circumference C having a radius R ₁₁ centered on the axis O of the disk 10 (the axis of the crankshaft 2).
₁₁ are provided rotatably around each of two support pins 11a provided in parallel with the axis O at 180 ° intervals. The center of gravity G ₁₁ of the eccentric mass 11 is located at a position shifted from the bonded portion by the support pin 11a,
Its eccentricity _{L 11 is} set to _{R 11/4.}
Therefore, from the above equation (2), the eccentric mass 11
This constitutes a dynamic vibration absorbing system that absorbs secondary torsional vibration in the crankshaft 2.

[0012] eccentric mass 12, the circumference _{C 11} concentric and of large diameter passing through the axis of the support pins 11a, the circumference C having a radius _{R 12
The} two support pins 12a provided on the base ₁₂ at intervals of 180 ° in parallel with the axis O are rotatably provided. Eccentric mass 12 with respect to the support pin 12a
Eccentricity _{L 12} of the center of gravity _{G 12} of less than eccentricity _{L 11} of the eccentric mass 11 is set to, for example, _R 12/16. Therefore, from the above equation (2), this eccentric mass 12 constitutes a dynamic vibration absorbing system that absorbs the fourth-order torsional vibration in the crankshaft 2.

The eccentric mass 13 is provided with the above-mentioned circumferences C ₁₁ and C _12.
Concentrically and of large diameter, on the circumference _{C 13} of radius _{R 13,} 18
Each of the two support pins 13a provided in parallel with the axis O at 0 ° intervals is rotatably provided. The center of gravity G ₁₃ of the eccentric mass 13 with respect to each of the support pins 13a
Eccentricity _{L 13} of less than eccentricity _{L 12} of the eccentric mass 12 is set to, for example, _R 13/36. Therefore, from the equation (2), the eccentric mass 13 constitutes a dynamic vibration absorbing system that absorbs sixth-order torsional vibration in the crankshaft 2.

That is, in the centrifugal pendulum type vibration absorber 1 having the above structure, when the disk 10 is rotated integrally with the crankshaft 2, the eccentric masses 11 to 11 on the disk 10 are generated by the centrifugal force generated thereby. 13 is the center of gravity G _{11 to} G
Rotate so that ₁₃ is on the outer peripheral side of each of the support pins 11a to 13a. Further, the disk 10 has a function as a “flywheel” that smoothens the rotation of the crankshaft 2 by substantially increasing the inertial mass of the flywheel.

As described above, torsional vibration generated in the crankshaft 2 includes components of various orders due to driving of the engine. Also, if the torsional direction natural frequency of the crankshaft 2 is f _t, this n-th order torsional vibration in the crankshaft 2, the rotation speed becomes maximum when the f _{t /} n, i.e., in the diagram of Figure 2 As shown by the solid line,
The peak of torsional vibration of the 6th order component appears when the rotation speed is _ft / 6, which is a relatively low rotation region, and the peak of torsional vibration of the 4th order component, when the rotation speed is _ft / 4, which is a higher rotation region. And a peak of the torsional vibration of the secondary component appears at a higher rotation speed _ft / 2.

When such torsional vibration is input to the centrifugal pendulum type vibration absorber 1, the eccentric masses 11 to 13 arranged on the disk 10 swing in accordance with the torsional vibration of each order. That is, for example, the eccentric mass 11 always oscillates at the same frequency as the frequency of the secondary vibration that changes in proportion to the rotation speed of the crankshaft 2, and the oscillating direction is the direction of the input torsional vibration. By contrast, the secondary vibration is reduced at any rotational speed. Similarly, the eccentric mass 12 reduces the fourth-order torsional vibration at any rotational speed, and the eccentric mass 13 absorbs the sixth-order torsional vibration at any rotational speed.

For this reason, for example, in the process of increasing the number of revolutions of the crankshaft 2, as shown by the chain line in FIG.
The peak of the torsional angle due to the torsional vibration of the sixth-order component that appears when the rotation speed is _ft / 6 is significantly reduced, and the torsional vibration due to the torsional vibration of the fourth-order component that appears when the rotation speed is _ft / 4, which is a higher rotation range. The peak of the angle is significantly reduced, and the peak of the torsion angle due to the torsional vibration of the second-order component that appears at a higher rotation speed _ft / 2 is significantly reduced.

The present invention is not limited by the illustrated embodiment. That is, in the above-described embodiment, the eccentric masses 11 to 1 are arranged on the circumferences having different radii.
The two disks 3 are provided at intervals of 180 °, but the disk 3 may be disposed so as not to cause an unbalance of the center of gravity of the disk 10. For example, the disks 3 may be provided at equal intervals in the circumferential direction (120 ° intervals) or more. . In addition, the R
The eccentric masses having different / L are not limited to three sets as in the above embodiment.

[0019] In the above embodiment, the support pins 11a~13a the eccentric mass 11 to 13, are disposed on different radii circumference _C 11 _{-C 13} together, this same radius on the circumference And by setting only the eccentric distances L _{11 to} L _{13 of} the eccentric masses 11 to ₁₃ to be different from each other, it is possible to provide the eccentric masses 11 to 13 with different order torsional vibration absorbing functions. The eccentric distance _L 11 _{~L 13} opposite to the same, even as different only radii _R 11 _{to R 13} in the circumferential _C 11 _{-C 13} together, each eccentric mass 11 to 13, different orders of torsional vibration absorbing Function can be given.

Further, in the above-described embodiment, the disk 10 is described as being mounted on a flywheel or the like. However, for example, the flywheel itself is used as a rotating disk of the centrifugal pendulum type vibration absorber of the present invention, and an eccentric mass is mounted thereon. A configuration is also possible.

[0021]

According to the centrifugal pendulum type vibration absorber according to the present invention, since each eccentric mass is provided with a different order of torsional vibration absorbing function, a plurality of orders of different rotational speed ranges where the twist angle peaks are provided. The torsional vibration can be effectively absorbed.

[Brief description of the drawings]

FIG. 1 is a front view schematically showing a preferred embodiment of a centrifugal pendulum type vibration absorber according to the present invention.

FIG. 2 is an explanatory diagram showing an operation of the centrifugal pendulum type vibration absorber of the embodiment.

FIG. 3 is a front view schematically showing an example of a conventional centrifugal pendulum type vibration absorber.

FIG. 4 is an explanatory view showing the operation of the conventional centrifugal pendulum type vibration absorber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Centrifugal pendulum-type vibration absorber 10 Disk (rotary disk) 11-13 Eccentric mass 11a-13a Support pin (support shaft) 2 Crankshaft

Claims (1)

[Claims] 1. A rotary disk (10) provided concentrically on a rotary shaft (2) to be subjected to vibration absorption, and an eccentric rotatably disposed on the rotary disk (10) via support shafts (11a to 13a). Masses (11 to 13), wherein the eccentric masses (11 to 13) have a radius (R) of a rotation trajectory of a support shaft (11a to 13a) centered on an axis of the turntable (10); A centrifuge characterized in that a plurality of sets having different ratios (R / L) from eccentric distances (L) from the axis of each of the spindles (11a to 13a) to the center of gravity of the eccentric masses (11 to 13) are arranged. Pendulum type vibration absorber.