JPH11210834A - Torque fluctuation absorbing damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simply structured torque fluctuation absorbing damper without additionally providing a one way clutch mechanism. SOLUTION: A coupling section 5 comprising a hub 1 and a pulley body 3 elastically connected to each other comprises a second elastomer member 51, which is vulcanizedly adhered integrally to the external periphery of a cylindrical section 12, and a coil spring 52, which is buried in this second elastomer member 51, and one end of the coil spring 52 is fixed to the side of the hub 1, and the other end 52b, which spirally extends to the opposite side of the rotation direction in the second elastomer member 51 from the side of the hub 1, is fixed to the side of a pulley body 3. Since in the torsion input to the rotation direction, the torsion deformation attended by the reduction in the diameter of the coil spring 52 of the coupling section 5 is restrained by the cylindrical section 12 of the hub 1, 100% torque transmission to the pulley body 3 from the hub 1 is made, and since in the torsion input in the reverse direction, the torsion deformation of the coupling 5 is permitted, torque fluctuation is effectively absorbed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque fluctuation absorbing damper provided on a pulley for transmitting a torque of a drive shaft of an internal combustion engine or the like to another rotating device, for absorbing a fluctuation of the transmitted torque.

[0002]

2. Description of the Related Art A part of driving force from an internal combustion engine of an automobile is supplied from a pulley provided at the tip of a crankshaft to various auxiliary devices such as an alternator and a compressor through an endless belt. Since it is rotated with torque fluctuation due to each stroke of the internal combustion engine,
The pulley is provided with a torque fluctuation absorbing damper for absorbing torque fluctuation and smoothing transmission torque.

According to the prior art, this type of torque fluctuation absorbing damper is composed of a hub attached to the shaft end of a crankshaft and a pulley body which is disposed on the outer periphery thereof through a bearing so as to be relatively displaceable in a circumferential direction. A coupling member made of an elastomer elastically connected to the hub,
A dynamic vibration absorber having a structure in which an annular mass body is elastically connected via an elastomer member is provided. That is, the coupling member absorbs the fluctuation of the transmission torque from the crankshaft by being subjected to torsional deformation between the hub and the pulley body, and the dynamic vibration absorbing portion controls the torsion of the crankshaft in a predetermined frequency range. By resonating in a phase different from the vibration, torsional vibration of the crankshaft is reduced.

[0004] In addition, this type of torque fluctuation absorbing damper has a one-way clutch mechanism between a hub and a pulley body, which has a torque transmitting function only in a driving direction of a crankshaft and is free in a reverse direction. There is one that is configured. That is, at the time of startup or sudden increase in torque due to sudden acceleration or the like, the hub and the pulley body are connected via the one-way clutch mechanism and torque transmission is performed. It is possible to prevent damage due to excessive torsional deformation caused by the rise.

[0005]

However, in the above-described torque fluctuation absorbing damper, since the hub and the pulley body constitute a one-way clutch mechanism, there is a problem that the structure and the shape are complicated.

The present invention has been made in view of the above circumstances, and a main technical problem thereof is to realize the performance of a torque fluctuation absorbing damper having a one-way clutch mechanism with a simple structure. It is in.

[0007]

Means for Solving the Problems As means for effectively solving the above-mentioned technical problems, a torque fluctuation absorbing damper according to the present invention comprises a hub attached to a drive shaft and a circumferential portion formed on the outer periphery of a cylindrical portion thereof. A coupling portion elastically connected to a pulley main body disposed in a state capable of relative displacement in the direction, and a state in which the annular mass body can be relatively displaced in the circumferential direction via the first elastomer member to the hub. A dynamic vibration absorbing portion having a coupled structure, wherein the coupling portion is a cylindrical second elastomer member disposed on the outer peripheral surface of the cylindrical portion, and a coil spring embedded in the second elastomer member. One end of the coil spring is fixed to the hub side, and the inside of the second elastomer member spirally extends from the one end in the direction opposite to the rotation direction of the drive shaft, and the other end is directed to the pulley body side. It is deemed to have been constant.

In the above structure, the dynamic vibration absorber reduces the torsional vibration of the drive shaft itself by resonating with the torsional vibration of the drive shaft in a predetermined frequency range with a predetermined phase difference.

The coupling portion is torsionally deformed in a direction in which the coil spring is reduced in diameter in the case of a torsional input in a forward direction with respect to the rotation direction of the drive shaft, ie, a torsional input in which the hub attempts to rotate ahead of the pulley body. Receive strength. This is because the coil spring has a shape that spirally extends from one end fixed to the hub side to the other end fixed to the pulley body side in a direction opposite to the rotation direction of the drive shaft. However, since the torsional deformation accompanying the diameter reduction of the coil spring is prevented by the cylindrical portion of the hub existing on the inner periphery thereof, such circumferential relative displacement of the pulley body and the hub in the torsional direction is restricted, 100% torque is transmitted from the hub to the pulley body via the coil spring. Further, since the action is given by winding the coil spring around the outer peripheral surface of the cylindrical portion,
No interference sound is generated.

On the other hand, in the case of a torsional input in the direction opposite to the rotational direction of the drive shaft, that is, a torsional input in which the pulley body tries to rotate ahead of the hub, the coil spring expands due to the characteristics of the shape described above. Subject to torsional deformation with diameter. The torsional deformation of the coil spring is not directly restricted by the cylindrical portion of the hub. The vibration absorbing effect by the torsional elasticity is exhibited, and the Coulomb damping effect by the internal friction of the second elastomer member which is subjected to the torsional deformation accompanying the deformation of the coil spring is exhibited.

In the present invention, more preferably, the second elastomer member in the coupling portion is integrally bonded to the outer peripheral surface of the cylindrical portion of the hub. With this configuration, the spring constant of the second elastomer member is increased as compared with the case where the second elastomer member is not adhered to the cylindrical portion, so that the strength against the torsional force in the direction opposite to the driving rotation direction increases, and the coupling portion Excessive deformation of the (coil spring and the second elastomer member) can be effectively suppressed.

[0012]

FIG. 1 is a half sectional view of a preferred embodiment of a torque fluctuation absorbing damper according to the present invention, cut along a plane passing through an axis thereof, and reference numeral 1 denotes a crankshaft of an internal combustion engine. This is a hub attached to a shaft end (not shown). The hub 1 is manufactured by press-forming a metal plate such as a steel plate. The hub 1 has an inner peripheral flange portion 11 having a shaft hole 11a which is a mounting portion to the crankshaft at the center thereof, and an outer periphery thereof. A cylindrical portion 12 formed in a cylindrical shape
And an outer peripheral flange 13 formed from the opposite side of the inner peripheral flange 11 to the outer peripheral side of the cylindrical portion 12.

A pulley body 3 is disposed on the outer periphery of the cylindrical portion 12 of the hub 1 via a bearing 2 so as to be relatively displaceable in the circumferential direction. The bearing 2 is made of, for example, a low-friction synthetic resin material, and includes a radial bearing portion 21 closely contacted with the outer peripheral surface of the cylindrical portion 12 and the radial bearing portion 21 near the inner peripheral flange portion 11 of the hub 1. Thrust bearing portion 2 bent from the end to the outer peripheral side
2 and has a substantially L-shaped cross section. Also,
The pulley body 3 is formed by press-forming or bending a metal plate such as a steel plate, and includes a base cylinder portion 31 slidably supported on the outer peripheral surface of the radial bearing portion 21;
The base cylinder portion 31 has a radial portion 32 formed from the end near the inner peripheral flange portion 13 toward the outer peripheral side, and a V pulley groove portion 33 formed on the outer peripheral edge thereof with a V-shaped cross section. .

A dynamic vibration absorber 4 is provided on an outer peripheral flange 13 of the hub 1. The dynamic vibration absorber 4 includes an annular mass 41 made of steel or the like concentrically spaced apart from the outer periphery of the cylindrical portion 12 of the hub 1, and the annular mass 41 is connected to the outer peripheral flange 13 of the hub 1. An annular first elastomer member 42 elastically connected to the
A predetermined natural frequency in the torsional direction is set by the inertial mass of the first elastic member and the spring constant of the first elastomer member 42. The annular mass body 41 has a shape in which an inner peripheral portion 41 a protrudes in the axial direction into a space on the inner peripheral side of the V-pulley groove portion 33 in the pulley main body 3. The required mass for obtaining a sufficient vibration absorption force is secured.

The base body 31 of the pulley body 3 is elastically connected to the hub 1 via the coupling part 5.
The coupling portion 5 includes a cylindrical second elastomer member 51 integrally vulcanized and bonded to the outer peripheral surface of the cylindrical portion 12 of the hub 1 and a coil spring embedded in the second elastomer member 51. 52. The coil spring 52 has one end 52a shown in a perspective view of FIG. 2 fixed to the inner peripheral portion of the outer peripheral flange portion 13 of the hub 1 by welding or an appropriate fixing means.
1 spirally extends in the direction opposite to the direction of rotation of the crankshaft shown in FIG.
(Or notch) 31 opened at the end of the base cylinder 31
a and is fixed. Further, the coil spring 52 is unevenly distributed at a position near the inner periphery of the second elastomer member 51, that is, substantially in contact with the outer peripheral surface of the cylindrical portion 12 of the hub 1.

The first elastomer member 42 in the dynamic vibration absorber 4 and the second elastomer member 51 in the coupling unit 5 can be formed in a mutually continuous shape or simultaneously. That is, in a given mold,
The first elastomer member 42 and the second elastomer member are formed by positioning and positioning the hub 1 having the coil spring 52 attached to the outer periphery of the cylindrical portion 12 and the annular mass body 41 and shaping the molding elastomer material. 51 is vulcanized and vulcanized and adhered in the shape shown.

The torque fluctuation absorbing damper having the above configuration is mounted on the inner peripheral flange 11 of the hub 1 at the shaft end of the crankshaft penetrating through the chamber wall of the crankcase of the internal combustion engine, and is rotated together with the crankshaft. Pulley body 3
A V-belt (not shown) for transmitting a rotational torque to a rotation shaft of an auxiliary device such as an alternator is hung on the V-pulley groove portion 33 of FIG. That is, the driving force of the crankshaft is transmitted from the hub 1 to the pulley body 3 via the coupling portion 5, and is further applied from the pulley body 3 to the pulley of the rotating shaft of the auxiliary device via the V-belt.

The internal combustion engine of an automobile or the like is driven while repeating the steps of intake, compression, explosion (expansion) and exhaust, and the reciprocating motion of the piston is converted into rotary motion by a crankshaft. The shaft undergoes periodic torque fluctuations (torsional vibration) with rotation.
Then, while rotating in a certain direction together with the crankshaft, the dynamic vibration absorber 4 is torsionally resonated with a predetermined phase difference from the torsional vibration by torsional vibration input through the hub 1 in a predetermined frequency range. The annular mass 41 is repeatedly displaced in the torsional direction relative to the hub 1 in the same cycle as the torsional vibration cycle of the crankshaft and in a direction to cancel the torsional displacement of the hub 1. The action reduces torsional vibration of the crankshaft.

The bearing 2 supports the pulley body 3 concentrically with respect to the hub 1 in a radial bearing portion 21 so as to be capable of torsional displacement, so that the pulley body 3 is not eccentric due to the tension of the V-belt. At 22, the behavior of the pulley body 3 in the axial direction is restricted (prevented from coming off). Then, the hub 1 and the pulley body 3
Are displaced from each other, the bearing 2 and the pulley body 3 slide, so that a part of the kinetic energy is converted into frictional heat, which results in a vibration damping effect (Coulomb damping).
Is obtained.

The coupling section 5 operates as follows in accordance with fluctuations in the torque of the crankshaft. First, for example, when a torsional force is input to the pulley body 3 in a direction in which the hub 1 is relatively displaced in the rotation direction of the crankshaft, the coil spring 52 in the coupling portion 5
Is that the one end 52a fixed to the hub 1 and the other end 52b fixed to the pulley body 3 are relatively displaced in the directions of arrows A and A 'shown in FIG. Subject to torsional deformation in the direction. However, since the torsional deformation of the coil spring 52 accompanying the diameter reduction is restricted by the cylindrical portion 12 of the hub 1, the torsion deformation is thereby reduced.
Is prevented from rotating relative to the pulley body 3, and the torque from the hub 1 is transmitted to the pulley body 3 via the coil spring 52 as it is. Moreover, at this time, an interference sound unlike the case where the relative displacement between the hub 1 and the pulley body 3 is restricted by the abutting operation of the stopper member or the like does not occur.

Conversely, when a torsional force is applied to the pulley body 3 such that the hub 1 is relatively displaced in the direction opposite to the rotation direction of the crankshaft, the coil spring 52 in the coupling portion 5 Are one end 52a fixed to the hub 1 side and the other end 5 fixed to the pulley body 3 side.
2b are relatively displaced in the directions of arrows B and B 'shown in FIG. 2, respectively, so that they undergo torsional deformation in a direction involving an increase in diameter. The cylindrical portion 12 of the hub 1 does not directly restrict such torsional deformation with the diameter expansion of the coil spring 52, and the elasticity of the second elastomer member 51 allows the torsional deformation with a certain diameter expansion. Therefore, the torque fluctuation is effectively absorbed by the elastic deformation of the coil spring 52 in the torsional direction. On the other hand, an appropriate damping force for the deformation operation of the coil spring 52 is generated in the second elastomer member 51 due to internal friction caused by the deformation.

The second elastomer member 51 is a hub 1
The vulcanized adhesive has a large spring constant, and elastically restrains the coil spring 52 to suppress its excessive torsional displacement.

The present invention is not construed as being limited to the illustrated embodiment. For example, the coil spring 52 in the coupling unit 5 is not necessarily the hub 1
It is not necessary to be in contact with the outer peripheral surface of the cylindrical portion 12, that is, a part of the second elastomer member 51 may be interposed between the cylindrical portion 12 and the coil spring 52.

[0024]

In the torque fluctuation absorbing damper according to the present invention, the coupling portion elastically connecting the hub and the pulley body transmits 100% torque when the torsional force is input in the rotational direction, and Since it has a function of absorbing torque fluctuation by deformation of the coil spring and the second elastomer member at the time of torsional input in the opposite direction,
The structure can be simpler than a case where a one-way clutch mechanism or the like is separately provided, and furthermore, the relative displacement of the pulley body and the hub in the circumferential direction is restricted by the hard members abutting in the circumferential direction. An excellent effect that interference noise is not generated unlike when a stopper or a one-way clutch is provided is realized.

[Brief description of the drawings]

FIG. 1 is a half sectional view showing a preferred embodiment of a torque fluctuation absorbing damper according to the present invention by cutting along a plane passing through an axis.

FIG. 2 is a schematic perspective view showing an operation of a coil spring of a coupling unit in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hub 11 Inner peripheral flange part 11a Shaft hole 12 Cylindrical part 13 Outer peripheral flange part 2 Bearing 21 Radial bearing part 22 Thrust bearing part 3 Pulley main body 31 Base cylinder part 31a Small hole 32 Radial part 33 V pulley groove part 4 Dynamic vibration absorption Part 41 Annular mass body 41a Inner peripheral part 42 First elastomer member 5 Coupling part 51 Second elastomer member 52 Coil spring

Claims (2)

[Claims] 1. A hub (1) attached to a drive shaft and a pulley body (3) arranged on the outer periphery of a cylindrical portion (12) thereof so as to be relatively displaceable in a circumferential direction. And a dynamic vibration absorber having a structure in which an annular mass body (41) is connected to the hub (1) via a first elastomer member (42) so as to be relatively displaceable in a circumferential direction. (4), wherein the coupling part (5) is a cylindrical second elastomer member (5) disposed on the outer peripheral surface of the cylindrical part (12).
1) and a coil spring (52) embedded in the second elastomer member (51). One end (52a) of the coil spring (52) is fixed to the hub (1) side. ), The inside of the second elastomer member (51) spirally extends in the direction opposite to the rotation direction of the drive shaft, and the other end (52b) is fixed to the pulley body (3). Torque fluctuation absorption damper. 2. The torque fluctuation absorbing device according to claim 1, wherein the second elastomer member (42) is integrally adhered to an outer peripheral surface of the cylindrical portion (12) of the hub (1). damper.