JP2003247598A - Torque fluctuation absorbing damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent generation of contact noise by a deformation limiting means for a coupling rubber when inputting excessive torque fluctuation, and improve a torque fluctuation absorbing performance. <P>SOLUTION: Since a coupling rubber 32 for elastically connecting between a hub 1 and a pulley 31 has a gap, the spring constant in the circumferential direction is lowered to obtain an excellent torque fluctuation absorbing performance. An increase in a deformation quantity of the coupling rubber 32 caused by the increase in a circumference direction relative displacement quantity of the hub 1 and the pulley 31 is limited by a contact between a stopper 5 arranged on the gap and the coupling rubber 32. As a result, grating contact noise can be prevented. Even after the contact between the stopper 5 and the coupling rubber 32, the torque fluctuation absorbing operation is also carried out by deformation of the coupling rubber 32 in the contact part, whereby the relative displacement of the hub 1 and the pulley 31 in the circumference direction can be cusionedly stopped. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque fluctuation damper for transmitting a driving torque in an internal combustion engine or the like to a rotating device and absorbing a fluctuation in the torque. 2. Description of the Related Art A part of a driving force from an internal combustion engine of an automobile is supplied from a pulley provided at a tip of a crankshaft to an auxiliary device such as an alternator or a water pump through an endless belt. Since the crankshaft is rotated with torque fluctuations caused by the intake, compression, explosion (expansion), and exhaust strokes of the internal combustion engine, the pulleys absorb torque fluctuations and torque fluctuations for smoothing transmission torque. An absorption damper is provided. A typical prior art of this kind of torque fluctuation absorbing damper is, for example, Utility Model Registration No. 260566.
There is one disclosed in No. 2. Torque fluctuation absorbing damper (decoupled damper pulley) according to this conventional technology
Includes a hub attached to the shaft end of the crankshaft and rotating integrally therewith, and a dynamic vibration absorbing portion and a coupling portion attached to the hub. The dynamic vibration absorber has a structure in which an annular mass is attached to the outer periphery of the rim of the hub via a damper rubber. The coupling portion has a structure in which a hub and a pulley which is rotatably supported on a rim portion of the hub via a bearing are connected via an annular coupling rubber. The relative torsional displacement of the pulley and the pulley is limited by engagement between a stopper pin attached to the annular mass body and an elongated hole formed in the pulley. That is, this torque fluctuation absorbing damper is:
In the coupling portion, the drive torque of the internal combustion engine input from the crankshaft to the hub is transmitted to the pulley while absorbing the torsional shearing deformation of the coupling rubber in the coupling portion, and the dynamic vibration is constituted by the damper rubber and the annular mass body. The portion resonates in a phase opposite to the torsional vibration of the crankshaft in a predetermined frequency range where the torsional amplitude of the crankshaft increases, thereby exhibiting a vibration damping function of reducing the torsional vibration. [0005] However, according to the conventional torque fluctuation absorbing damper, the coupling rubber has a simple annular shape continuous in the circumferential direction. , The torsional shear spring constant when the torque fluctuation is input is relatively high, in other words, the rigidity is large. Therefore, the amount of deformation of the coupling rubber with respect to the input of torque fluctuation is small, and sufficient torque fluctuation absorbing performance cannot be obtained. When an excessive torque fluctuation is input, the relative displacement of the hub and the pulley in the torsional direction is limited by the engagement between the stopper pin attached to the annular mass body and the elongated hole formed in the pulley. However, at this time, there is a problem that a contact noise occurs between the stopper pin and the elongated hole of the pulley. Moreover, in a state where the relative displacement of the hub and the pulley in the torsional direction is suppressed by the contact between the stopper pin and the elongated hole of the pulley, the torque variation absorbing function is lost, that is, the increase in the torque variation after the contact with the elongated hole of the pulley is reduced. Could hardly be absorbed. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a technical problem thereof is to prevent the generation of contact noise due to the deformation limiting means of the coupling rubber when an excessive torque fluctuation is input. Another object of the present invention is to improve torque fluctuation absorbing performance. As a 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 rotating shaft, and a hub mounted on the hub. A relatively rotatable pulley is elastically connected to the pulley via a coupling rubber, and the coupling rubber is provided with a plurality of cavities at predetermined intervals in a circumferential direction. It is loosely fitted with a hub or a stopper provided on the pulley at a predetermined interval in the circumferential direction with a predetermined clearance in the circumferential direction. That is, since the coupling rubber has a gap, the spring constant in the circumferential direction is reduced, and the stopper limits the relative displacement of the hub and the pulley in the circumferential direction due to contact with the coupling rubber. FIG. 1 is a sectional view showing a preferred embodiment of a torque fluctuation absorbing damper according to the present invention, cut along a plane perpendicular to an axis O thereof, and FIG. In 1
It is II-O-II 'line sectional drawing. Note that the “front side” used in the following description is the left side in FIG. 2, and the “back side” is the right side in FIG. 2 where the internal combustion engine is present. The “circumferential direction” is the direction of the circumference around the axis O. As shown in FIGS. 1 and 2, a torque fluctuation absorbing damper according to the present embodiment includes a hub 1 attached to a shaft end of a crankshaft of an internal combustion engine for an automobile, and the hub 1.
And a dynamic vibration absorbing section 2 and a coupling section 3 provided on the outer peripheral side of the first section. The hub 1 is formed by stamping and press-forming a metal plate, and has a substantially U-shaped annular cross section cut along a plane passing through the axis O (FIG. 2). None, that is, a mounting cylinder portion 1a fixed to the crankshaft, a radial portion 1b extending from the front end to the outer peripheral side, and concentric with the mounting cylindrical portion 1a extending from the outer periphery of the radial portion 1b to the rear side. The rim 1c is formed in an intended manner. The dynamic vibration absorbing portion 2 is a sleeve 2 press-fitted to the outer peripheral surface of the rim portion 1c of the hub 1 with an appropriate interference.
1 and an annular mass 22 concentrically arranged on its outer periphery
And a damper rubber 23 for elastically connecting the sleeve 21 and the annular mass body 22. The natural frequency of the torsion direction is a predetermined frequency range in which the torsion angle of the crankshaft is maximized, in other words, the torsion of the crankshaft. It is tuned to match the directional natural frequency. The sleeve 21 is manufactured by cutting a metal tube or the like, and the annular mass body 22 is manufactured by casting or cutting a thick metal tube.
The damper rubber 23 is formed by integrally vulcanizing and vulcanizing a rubber-like elastic material between opposing peripheral surfaces of the sleeve 21 and the annular mass body 22. That is, the dynamic vibration absorber 2
Are the sleeve 21 and the annular mass body 22 and the damper rubber 23
Then, the sleeve 21 is attached to the hub 1 by press-fitting the sleeve 21 to the outer peripheral surface of the rim portion 1c of the hub 1. The coupling section 3 comprises a pulley 31, coupling rubber 32 for elastically connecting the pulley 31 and the hub 1, and bearings 33 for holding the pulley 31 concentrically with the hub 1. The pulley 31 is formed by stamping and pressing a metal plate, and has a substantially U-shaped annular cross section (cross section shown in FIG. 2) cut along a plane passing through the axis O. None, that is, a pulley body 31a extending so as to surround the outer peripheral side of the annular mass body 22 and having a poly-V groove 31b formed on the outer peripheral surface, and a radial portion 31c extending from the rear end to the inner peripheral side. And a supported tubular portion 31 d extending from the inner peripheral end of the radial portion 31 c to the front side and inserted into the outer periphery of the mounting tubular portion 1 a of the hub 1. The coupling rubber 32 is integrally formed and vulcanized and bonded to the outer peripheral surface of the supported cylindrical portion 31d of the pulley 31 and is bonded to the inner peripheral surface of the rim portion 1c of the hub 1 by an adhesive. It is integrated.
Further, the coupling rubber 32 has a strength necessary for transmitting torque, and as shown in FIG.
Are arranged at intervals of .degree., And gaps 4 are formed between the coupling rubbers 32, 32,. With such an intermittent shape in the circumferential direction, the shear spring constant in the circumferential direction is set sufficiently low. The bearing 33 is made of a synthetic resin material having a low friction coefficient such as PTFE and having excellent wear resistance. The bearing 33 is formed in a cylindrical shape. The hub 1 and the pulley 31 are concentrically supported between the supported cylindrical portion 31d and the inner peripheral surface of the supported cylindrical portion 31d so as to be relatively rotatable. In the gaps 4, 4,... Between the coupling rubbers 32, 32,... In the coupling portion 3, bar-shaped stoppers 5 are arranged, and one end of each of the stoppers 5 is, for example, a pin or a screw. The hub 1 is fixed to the radial portion 1b by an appropriate fixing means 5a. The gap 4 is larger than the stopper 5, and a predetermined clearance 4 a by the gap 4 exists between each stopper 5 and each coupling rubber 32 on both sides in the circumferential direction. The size of the clearance 4a is determined in consideration of the maximum value of the relative displacement between the hub 1 and the pulley 31 in the circumferential direction, which is allowed from the strength of the coupling rubbers 32, 32,.
When the torque fluctuation is properly set and the torque fluctuation is not input, the both sides of each stopper 5 have the same size. Therefore, each stopper 5 includes the hub 1 and the pulley 3
When the relative displacement in the circumferential direction with respect to the coupling rubber 1 reaches a predetermined value, the coupling rubber 32 comes into contact with each coupling rubber 32 and the pulley 31
In the circumferential direction relative to the coupling rubber 32
Is prevented from excessive torsional deformation. In assembling the torque fluctuation absorbing damper of the present embodiment, first, a damper rubber 23 is integrally formed of a rubber-like elastic material by vulcanization molding and vulcanization bonding between opposing peripheral surfaces of the sleeve 21 and the annular mass body 22. On the other hand, the coupling rubber 32 is integrally vulcanized and vulcanized and bonded to the outer peripheral surface of the supported cylindrical portion 31d of the pulley 31 with a rubber-like elastic material, and is also attached to the outer peripheral surface of the mounting cylindrical portion 1a of the hub 1. The bearing 33 is extrapolated, and the stopper 5 is attached to the radial portion 1b of the hub 1. Then, the dynamic vibration absorbing portion 2 which is a vulcanized molded body of the sleeve 21 and the annular mass body 22 and the damper rubber 23 is attached to the hub 1 by press-fitting the sleeve 21 to the outer peripheral surface of the rim portion 1c of the hub 1, In addition, an adhesive is applied in advance to the outer peripheral end of each coupling rubber 32 and / or the inner peripheral surface of the rim 1c of the hub 1 so that the coupling rubbers 32, 32,
While the gaps 4 and the stoppers 5 are aligned with each other, the supported cylindrical portion 31d of the pulley 31 and the coupling rubbers 32, 32,. Insert between 33. Since an appropriate interference is set between the sleeve 21 in the dynamic vibration absorbing portion 2 and the rim portion 1c of the hub 1, the damper rubber 23 slightly moves in the radial direction during the mutual press-fitting process. Accordingly, the tensile stress in the radial direction caused by shrinkage of the damper rubber 23 after being formed between the sleeve 21 and the annular mass body 22 is effectively eliminated or reduced. Also, an appropriate interference can be set between the coupling rubber 32 and the rim portion 1c of the hub 1. The torque fluctuation absorbing damper according to the present embodiment is rotated together with the crankshaft by mounting the hub 1 externally on the shaft end of the crankshaft of the internal combustion engine. The torque of the crankshaft is applied to the pulley 31 from the rim 1 c of the hub 1 via the coupling rubber 32.
Is transmitted to A V-belt (not shown) for transmitting driving torque to the rotation shaft of the auxiliary device is wound around a poly-V groove 31b formed on the outer peripheral surface of the pulley body 31a of the pulley 31. The internal combustion engine is driven while repeating the steps of intake, compression, explosion (expansion) and exhaust, and converts the reciprocating motion of the piston into the rotational motion of the crankshaft. , A periodic torque fluctuation occurs with the rotation, and this torque fluctuation is effectively absorbed by the shearing deformation operation of the coupling rubber 32 in the coupling portion 3, so that the transmission torque to the V-belt is smoothed. You. In the frequency range where the torsion angle due to the torsional vibration of the crankshaft is maximum, the sub-vibration system including the annular mass body 22 and the damper rubber 23 in the dynamic vibration absorber 2 resonates in the circumferential direction, and the torque due to the resonance is reduced. Since the direction and the direction of the input vibration torque are reversed, the peak of the torsion angle of the crankshaft can be effectively reduced. Since the coupling rubber 32 has a shape interrupted in the circumferential direction, the coupling rubber 32 has a sufficiently low shearing spring constant in the circumferential direction as compared with a conventional rubber continuous in the circumferential direction. It has become. For this reason, an excellent torque fluctuation absorbing function is exhibited by being greatly sheared in response to the input of torque fluctuation and converted into heat energy due to internal friction. When the torque fluctuation is input, the hub 1 and the pulley 31 are relatively displaced in the circumferential direction with the sliding of the bearing 33 and the deformation of the coupling rubber 32, and the displacement (amplitude) is the torque fluctuation. Increases with width. In addition, since the vibration system including the coupling rubber 32 and the pulley 31 has a torsional resonance region in a low frequency region as compared with the dynamic vibration absorber 2, the hub 1 can also resonate in a low speed rotation region. And the relative displacement of the pulley 31 in the circumferential direction increases. Then, the one-sided amplitude corresponds to each coupling rubber 3
When the circumferential clearance 4a of the stopper 2 and the stopper 5 reaches the size, the stopper 5 comes into contact with the coupling rubber 32, so that the relative displacement of the hub 1 and the pulley 31 in the circumferential direction is limited. It is possible to prevent the rubber 32 from undergoing excessive torsional deformation. Since the stopper 5 comes into contact with the coupling rubber 32, no unpleasant contact noise is produced. Moreover, since the coupling rubber 32 is deformed at the contact portion when it comes into contact with the stopper 5, even after the stopper 5 comes into contact with the coupling rubber 32, the circumferential direction of the hub 1 and the pulley 31 due to a certain torque fluctuation. Relative displacement is allowed. For this reason, the stopper 5 and the coupling rubber 3
Due to the contact with 2, the circumferential relative displacement between the hub 1 and the pulley 31 is damped. The pulley 31 has a radial portion 31c.
Has a shape that covers the entirety of the coupling rubber 32 and the dynamic vibration absorber 2 from the rear side, so that radiant heat from the internal combustion engine existing on the rear side to the coupling rubber 32 and the damper rubber 23 is effectively shut off. Therefore, deterioration of the coupling rubber 32 and the damper rubber 23 due to heat can be prevented, and excellent performance can be exhibited for a long period of time. The present invention is not limited to the above embodiment. For example, although the stopper 5 is attached to the hub 1 in the illustrated embodiment, the object of the present invention can be realized by attaching the stopper 5 to the pulley 31, and the number of the stopper 5 and the coupling rubber 32 (the gap 4) is reduced. The size and size are also arbitrarily set according to the use conditions. Further, in the above-described embodiment, the torque has been described as being transmitted from the hub 1 to the pulley 31. However, in the present invention, the driving torque input from the outside to the pulley 31 via the belt It can also be applied as a torque fluctuation absorbing means when transmitting to a rotating shaft via a. In the illustrated embodiment, the gap 4 is formed by coupling rubbers 32, 32,
.., But the coupling rubber 32 has a shape continuous in the circumferential direction, and the gap 4 is formed by the coupling rubber 32.
It may be formed in a hole shape (window shape) or a non-penetrating blind hole shape. As described above, according to the torque fluctuation absorbing damper according to the present invention, since the coupling rubber has a gap, the spring constant in the circumferential direction can be reduced to achieve excellent torque fluctuation. Absorption performance can be obtained. Further, an increase in the amount of deformation of the coupling rubber due to an increase in the relative displacement between the hub and the pulley in the circumferential direction is limited by the contact between the coupling rubber and the stopper disposed in the gap, so that it is unpleasant. No contact noise is generated, and the deformation of the coupling rubber due to the contact with the stopper allows the torque fluctuation absorbing operation to be performed even after the contact between the stopper and the coupling rubber, and reduces the circumferential relative displacement between the hub and the pulley. It can be buffered.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing a preferred embodiment of a torque fluctuation absorbing damper according to the present invention, cut along a plane orthogonal to an axis O thereof. FIG. 2 is a sectional view taken along line II-O-II 'of FIG. [Description of Signs] 1 Hub 1a Mounting cylinder portion 1b Radial portion 1c Rim portion 2 Dynamic vibration absorbing portion 21 Sleeve 22 Annular mass body 23 Damper rubber 3 Coupling portion 31 Pulley 31a Pulley body 31b Poly V groove 31c Radial portion 31d Support cylinder part 32 Coupling rubber 33 Bearing 4 Void part 4a Clearance 5 Stopper 5a Fixing means

Claims (1)

Claims 1. A hub (1) mounted on a rotating shaft,
Pulley (31) rotatable relative to hub (1)
Are elastically connected to each other through a coupling rubber (32), and a plurality of voids (4) are provided in the coupling rubber (32) at predetermined intervals in the circumferential direction. (4) is loosely fitted to the hub (1) or the stopper (5) provided on the pulley (31) at a predetermined interval in the circumferential direction with a predetermined clearance (4a) in the circumferential direction. Torque fluctuation absorbing damper.