JP2001153185A - Dynamic damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dynamic damper having a simple structure, without increasing weight, having high reliability of a vibration reducing effect and being effective in reducing vibration of a high degree. SOLUTION: Housing chambers 12 are formed at a prescribed phase interval in a hub 11 installed on a crankshaft in a crank chamber of an engine. An outer peripheral side inside surface of the housing chambers 12 becomes a cylindrical recessed surface 12a with a line P12 parallel to the axis O11 by passing through the circumference C12 of a radius R12 of centering the axis O11 of the hub 11 as the curvature center. Rolling masses 15 are housed in the respective housing chambers 12. These rolling masses 15 move in the housing chambers 12 to the outer peripheral side by centrifugal force at rotating time of the hub 11, and effectively reduce torsional vibration of a specific degree in all rotating speeds by performing reciprocating behavior like a pendulum while rolling on the cylindrical recessed surface 12a by input of the torsional vibration. Oiling holes 14 are opened in the respective housing chambers 12, and a part of lubricating oil in the crank chamber enters to lubricate between an inner wall of the housing chambers 12 and the rolling masses 15.

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 3 or the like.

[0002]

2. Description of the Related Art An engine is driven while repeating intake, compression, explosion (expansion), and exhaust strokes. As shown in FIG. 6, a reciprocating motion of a piston 1 is transmitted through a connecting rod 2 to a crankshaft. 3, the torsional vibration (vibration in the rotational direction) is generated in the crankshaft 3 with the rotation. In order to prevent the occurrence of the trouble due to the increase of such torsional vibration, a dynamic damper 100 is attached to the shaft ends 3a and 3b of the crankshaft 3 protruding from the crankcase 4 of the engine to the outside. Conventionally, for example, a centrifugal pendulum type dynamic damper as shown in FIG. 7 is known.

The centrifugal pendulum type dynamic damper has a vibration absorbing mechanism using a centrifugal pendulum 103 whose frequency changes in proportion to the number of revolutions. For example, the distal end 3a of the crankshaft 3 protruding from the crank chamber 4 of the engine or the rear thereof is used. End 3b
Disc-shaped hub 101 attached to the
1 includes a plurality of pins 102 arranged at equal intervals on a circumference C having a predetermined radius R from the axis thereof, and a centrifugal pendulum 103 rotatably attached to each of the pins 102. According to this configuration, when the torsional vibration of the crankshaft 3 is input to the hub 101, each centrifugal pendulum 103 causes the axis O of the hub 101 (crankshaft 3) and the axis of the pin 102 to rotate around the pin 102. It swings to both sides of the line Q passing through the center P, and the direction of the torque due to the swing is opposite to the torque of the torsional vibration, thereby obtaining a damping force.

That is, the distance between the center of gravity G of the centrifugal pendulum 103 and the axis P of the pin 102, which is the center of its swing (hereinafter, referred to as the center)
Assuming that r is the behavior radius) and ω is the angular velocity of the hub 101, the natural frequency fe of the centrifugal pendulum 103 is represented by the behavior radius r and the centrifugal force field Rω ² depending on the angular velocity ω.

(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 appropriately setting R / r, the natural frequency fe of the centrifugal pendulum 103 is always equal to the frequency of the torsional vibration of the n-th component in the rotation of the 4-cylinder 4-cycle engine, for example. Since they change so as to be equal, torsional vibration of a specific order can be effectively reduced at any rotational speed.

However, the centrifugal pendulum type dynamic damper according to the prior art requires a pin 102 and a bearing (not shown) for rotatably supporting the centrifugal pendulum 103. However, the manufacturing cost is high and there is a problem in reliability.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its main technical problems a dynamic structure having a simple structure and a highly reliable vibration reduction effect. A damper can be manufactured.

[0007]

The above-mentioned conventional technical problems can be effectively solved by the present invention. That is, the dynamic damper according to the present invention is arranged such that at least a surface facing the inner peripheral side of the rotating disk is parallel to the axial center of the rotating disk which is located in the crank chamber of the engine and is concentrically mounted on the crankshaft 3 of the engine. A plurality of accommodation chambers each having a cylindrical concave surface having a curved line as a center of curvature are provided at predetermined intervals in a circumferential direction, and rolling masses are accommodated in the respective accommodation chambers so as to be able to roll, respectively. , A refueling hole was opened. 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. Since the rotating disk is located in the crank chamber and attached to the crankshaft 3 without the need for a pin supporting structure, a part of the lubricating oil circulated and supplied into the crank chamber is introduced into the housing chamber through the oil supply hole. Supplied.

[0008]

FIG. 1 schematically shows a first preferred embodiment of a dynamic damper according to the present invention. Dynamic damper 10 according to this embodiment
Is for reducing torsional vibration of a crankshaft of an automobile engine, which will be described later. Reference numeral 11 denotes an inner peripheral boss portion 11a.
A hub as a rotating disk attached to the crankshaft.

In the hub 11, four housing chambers 12 are provided at one phase with a 90 ° phase interval. Each accommodation room 12
Is the axis _{O 11} parallel to as the axis _{O 11} circumference _{C 1 2} radius _{R 12} around the line center of curvature P of the hub 11
Is formed in a cylindrical surface shape to _12, its open end is closed by a disk-shaped plate 13 made of a metal plate which is fitted on one end an outer circumferential surface of the boss portion 11a, respectively.

A substantially U-shaped notch 1 is formed on the outer peripheral edge of the side plate 13.
3 a are formed at 90 ° phase intervals corresponding to the respective accommodation chambers 12. The inner end of each notch 13a reaches the inner peripheral area of the opening of each of the storage chambers 12, and thereby the oil supply hole 14 is formed.

In each of the accommodation chambers 12, a rolling mass 1 is provided.
5 are accommodated. This rolling mass 15 is, for example, as shown in FIG.
A cylindrical shape as shown in (A), shown in (B)
Cylindrical or spherical as shown in (C)
And its radius r _FifteenIs the radius r of the accommodation room 12
₁₂It is smaller than that. Therefore this roll
The moving mass 15 is collected by centrifugal force when the hub 11 rotates.
The inside of the chamber 12 is moved toward the outer periphery of the hub 11 and the hub 1 is moved.
1 receives torsional vibration from the crankshaft 3
The axis O₁₁And the center of the accommodation room 12 (center of curvature)
P₁₂) And the line Q ₁₁So as to reciprocate on both sides of
The axis O of the inner surface of the storage chamber 12₁₁Circle facing side
It rolls on the cylindrical concave surface 12a.

More specifically, the cylindrical concave surface 12a of the accommodation chamber 12
Center of gravity G of rolling mass 15 rolling on top _FifteenTrajectory radius
Δr (referred to as the behavior radius) is the radius r of the rolling mass 15_Fifteen
And the radius of the accommodation chamber 12 (the radius of curvature of the cylindrical concave surface 12a) r
₁₂And the difference. That is, the rotation with the crankshaft 3
When torsional vibration is input to the rotating hub 11, the rolling
The cylindrical concave surface 15 corresponds to the center of the accommodation room 12.
Center of curvature P of 12a₁₂The radius of behavior Δr centered on
While rolling, it reciprocates like a pendulum.

Here, assuming that the angular velocity of the hub 11 is ω,
When the rolling mass 15 is in a roller shape as shown in FIG. 3A or 3B, the frequency fe of the reciprocating behavior is determined by the behavior radius Δr and the field of centrifugal force depending on the angular velocity ω. , By the inertial mass of the rolling mass 15,

(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 ₁₂ and Δr are:

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

That is, by appropriately setting R ₁₂ and Δr, the frequency fe of the reciprocating behavior of the rolling mass 15 is
Is always the same as the frequency of the n-th (eg, second-order) torsional vibration in the rotation of the engine, and the reciprocating behavior is performed with a predetermined phase difference from the input torsional vibration to reduce the torque in the vibration damping direction. appear. Therefore, the n-order vibration can be effectively reduced at any rotational speed.

Further, the _{r 12} (the radius of curvature of the cylindrical concave surface _12a) and the radius _{r 15} of the rolling mass 15 of the housing chamber 12 radius, it is possible to significantly reduce the behavior radius Δr of the rolling mass 15, By increasing the value of n, it is possible to obtain a dynamic damper that is effective for reducing high-order torsional vibration. Moreover, since there is no fact that the radius r ₁₅ of the rolling mass 15 by reducing the behavior radius Δr becomes inevitably small, it is possible to improve the vibration absorbing property gives the required mass rolling mass 15.

Further, the dynamic damper 10 does not require a support structure using pins and bearings as in the conventional centrifugal pendulum type dynamic damper shown in FIG. 7, so that the structure is simple. In addition, when a large number of vibration absorbing systems using the rolling mass 15 are provided, the number of the accommodation chambers 12 formed in the hub 11 increases with this, so that the weight does not increase.

FIG. 3 shows a schematic structure of an automobile engine. Reference numeral 3 in this figure denotes a crankshaft for converting the reciprocating motion of the piston 1 in each cylinder into a rotary motion via a connecting rod 2. The front end 3a and the rear end of the crankshaft 3 projecting from the crank chamber 4 to the outside. A pulley 5 for transmitting a driving force to the accessory and a flywheel 6 as a flywheel are attached to 3b, respectively. The dynamic damper 10 of the present invention is disposed in the crank chamber 4 as shown by a dashed line in FIG. 3, and is attached to one or more of the two side portions 3c to 3g of the crank arm of the crank shaft 3. Can be

Inside the engine, lubricating oil (engine oil) is sucked up by an oil pump (not shown) from an oil pan 7 provided in a lower portion of the crank chamber 4 and supplied to the operating portions of the respective pistons 1 from there. Each part is lubricated in the process of falling or flowing down and returning to the oil pan 7. The dynamic damper 10 of the present invention, which is located in the crank chamber 4 and attached to the crankshaft 3, has an oil supply hole 14 formed in a side plate 13 of the dynamic damper 10. Part of the oil enters the accommodation chamber 12 through the oil supply hole 14 and lubricates the space between the inner surface of the accommodation chamber 12 and the rolling mass 15 satisfactorily. Therefore, the operation of the rolling mass 15 is performed smoothly, wear and the like are suppressed, and the reliability of the vibration absorbing function can be made high.

In the embodiment shown in FIG. 1, an oil supply hole 14 has a U-shaped notch 13a formed in the outer peripheral edge of the side plate 13.
However, other configurations such as those illustrated in FIG. 4 can be used.

That is, in FIG. 4, (A) shows that the oil supply holes 14 correspond to the respective accommodation chambers 12 on the outer peripheral edge of the side plate 13.
It consists of cut-and-raised portions 13b formed at a phase interval of 0 °. 2B, the oil supply holes 14 are small holes formed in the side plate 13 at a phase interval of 90 ° corresponding to the respective accommodation chambers 12. (C), the accommodation room 12 is the hub 11
Are formed in the shape of a circular hole penetrating in the axial direction, and the openings at both ends in the axial direction are closed by two side plates 13A and 13B fitted to the outer peripheral surfaces of both ends of the boss portion 11a.
3A and 13B are provided with oil supply holes 14 formed of small holes.

Note that the arrangement of the storage chambers 12 may be any positional relationship that does not cause imbalance of the center of gravity of the hub 11, and FIG.
Is not limited to the 90 ° phase interval as described above.

By the way, when torsional direction natural frequency of the crankshaft 3 is f _t, n in the crankshaft 3
It is known that the next torsional vibration has a maximum torsional angle when the rotation speed is _ft / n. 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, by setting a plurality of combinations of the accommodation chamber 12 and the rolling mass 15 having different n values in the equation (4), torsional vibrations of a plurality of orders can be reduced. More preferably,

FIG. 5 shows an embodiment as an example. That is, in the dynamic damper 10, the accommodation chambers 12A and 12A which are 180 ° symmetrical to each other among the four accommodation chambers provided at a phase interval of 90 °.
A is formed on the cylindrical surface of the center of curvature _{P 12A} parallel lines and street the axis _{O 11} circumference _{C 12} of radius _{R 12} of the axis _{O 11} and the center of the hub 11, respectively.
The housing chambers 12B and 12B which are 90 ° out of phase and 180 ° symmetrical to each other have a long hole shape, and have a cylindrical concave surface 12a on the outer peripheral side and a cylindrical convex surface 12b on the inner peripheral side. And the center of curvature _P12B is on the circumference C12.

A radius r _12A of the circular storage chamber 12A;
The curvature radius r _12B of the cylindrical concave surface 12a of the elongated hole-like accommodating chamber 12B are identical to each other whereas the radius r of the rolling mass 15B accommodated in the long hole-like accommodating chamber 12B
_15B is smaller than the radius r _15A of the rolling mass 15A housed in the circular housing chamber 12A. For this reason, the relatively small diameter rolling mass 15B has a large behavior radius Δr, the value of n in equation (4) becomes small, and the relatively large diameter rolling mass 15A has a relatively small behavior radius. Since Δr decreases, the value of n increases.

Oil supply holes 14A and 14B are formed in side plates 13 provided on one side or both sides in the axial direction of the hub 11. These oil supply holes 14A and 14B correspond to the above-described FIG.
Or it is the same as FIG.

Therefore, according to this embodiment, the rolling mass 15A always behaves in the opposite direction to the input vibration at the same frequency as the frequency of the specific order of the crankshaft 3, so that the rolling mass 15A has this order at any rotational speed. Dynamic vibration absorbing system that effectively reduces the vibration of the motor. Similarly, the rolling mass 15B can be a dynamic vibration absorbing system that effectively reduces higher order torsional vibrations at all rotation speeds.

In addition to the configuration as in the above embodiment,
Or made different from each other behavior radius Δr of rolling mass 15, for example, by varying the cylindrical concave surface 12a of curvature radius r ₁₂ of the housing chamber 12 in FIG. 1, or the hub 1
By making the radius _{R 12} of the rotation locus of the curvature center _{P 12} of the cylindrical concave surface 12a centered on the first axis _{O 11} (circumference _{C 12) different,} the plurality of types having different _{R 12} / [Delta] r By setting a combination, the rolling mass 15 can be provided with a function of reducing torsional vibrations of different orders. Further, it is also possible to use three or more combinations of the accommodation chambers 12 and the rolling masses 15 having different R ₁₂ / Δr so that the torsional vibration of three or more orders can be reduced.

[0028]

According to the dynamic damper according to the present invention, since the rolling mass moves in a pendulum while rolling on the cylindrical concave surface in the accommodation chamber, the vibration damping function is achieved, thereby simplifying the structure. Since the behavior radius of the rolling mass can be significantly reduced, a structure capable of reducing high-order torsional vibration can be obtained. In addition, the dynamic damper is located in the crankcase of the engine and lubrication between the rolling mass and the inner wall of the housing chamber is lubricated by the lubricating oil that enters the housing chamber through the oil supply hole, so that the reliability of vibration absorption performance is high. Can be.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a dynamic damper according to the present invention, wherein (A) is a front view, and (B) is a BO of (A).
_{It is 11} sectional drawing.

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

FIG. 3 is an explanatory diagram schematically showing a relationship between a dynamic damper of the embodiment and an engine.

FIG. 4 is a half sectional view showing another structure of the oil supply hole in the embodiment.

FIG. 5 is a front view showing another embodiment of the dynamic damper according to the present invention.

FIG. 6 is an explanatory diagram schematically showing a relationship between a dynamic damper and an engine according to the related art.

7A and 7B are diagrams schematically illustrating an example of a centrifugal pendulum type dynamic damper according to the related art, in which FIG. 7A is a front view and FIG.
FIG. 3 is a cross-sectional view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piston 2 Connecting rod 3 Crankshaft 4 Crankcase 5 Pulley 6 Flywheel 7 Oil pan 10 Dynamic damper 11 Hub (rotary disk) 11a Boss part 12, 12A, 12B Storage chamber 12a Cylindrical concave surface 13, 13A, 13B Side plate (side wall part) 13a Notch 13b Cut-and-raised portion 14, 14A, 14B Oil supply hole 15, 15A, 15B Rolling mass

Claims (1)

[Claims] 1. A rotating disk (11) located in a crankcase (4) of an engine and concentrically mounted on a crankshaft (3) of the engine, at least the rotating disk (1).
1) the inner circumferential side facing surface is the axis (O ₁₁₎ of curvature centered on a line parallel with the (P 1 ₂₎ and the plurality of storage chambers having a cylindrical concave surface (12a) to (12) are circumferentially Provided at predetermined intervals,
A rolling mass (15) is accommodated in each of the accommodation chambers (12) in a rollable state, and each of the accommodation chambers (12) includes:
A dynamic damper characterized by having an oil supply hole (14).