JP2004286077A - Torque fluctuation absorbing damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a torque fluctuation absorbing damper capable of stabilizing a support of a pulley 3 owing to a bearing 5 for the long time. <P>SOLUTION: The damper is provided with a hub 1 attached to a crankshaft, a dynamic absorbing part 2 elastically connecting an annular mass body 21 to the hub 1 via a first elastic body 22, and a coupling 4 elastically connecting the pulley 3 to the hub 1 via a second elastic body 41. The first elastic body 22 and the second elastic body 41 are arranged at an inner perimeter of a rim 11b of an outer ring 11 in the hub 1. A pulley main body 31 of the pulley 3 is coaxially supported at the periphery of the rim 11b via a radial bearing 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a torque fluctuation absorbing damper used for an automobile, an agricultural machine, a machine tool, a small boat, etc., which transmits a torque from a drive shaft of an internal combustion engine or the like to another rotating device and absorbs a fluctuation in the torque.
[0002]
[Prior art]
A part of the driving force of the internal combustion engine of the vehicle is provided from a pulley provided at the tip of the crankshaft to an auxiliary machine such as an alternator or a water pump through an endless belt. Since the pulley is rotated with torque fluctuation, a torque fluctuation absorbing damper for absorbing torque fluctuation and smoothing transmission torque is used for the pulley.
[0003]
As a torque fluctuation absorbing damper according to the related art, for example, as described in Patent Document 1 below, a first elastic body is mounted on the outer periphery of a rim portion of a hub that is attached to a shaft end of a crankshaft and rotates integrally. The annular mass body is connected via a, and a flange portion extending inward from a pulley supported on the annular mass body via a radial bearing is axially connected to a hub via a second elastic body. Are known. This type of torque fluctuation absorbing damper has a dynamic vibration absorbing portion constituted by a first elastic body and an annular mass body, which has a dynamic vibration absorbing effect caused by resonating in a circumferential direction in a predetermined frequency range. In addition to reducing the torsional vibration of the shaft, the drive torque input to the hub from the crankshaft is transmitted to the pulley while absorbing the torque fluctuation by the circumferential shearing action of the second elastic body.
[0004]
[Patent Document 1]
Patent No. 3155280 (Fig. 1)
[0005]
[Problems to be solved by the invention]
However, according to the conventional torque fluctuation absorbing damper described in Patent Document 1, the pulley is supported on the outer periphery of the annular mass body via the radial bearing, and the annular mass body itself forms the first elastic body. Because the elastic mass is elastically supported by the hub, the eccentric load acts on the radial bearing due to the run-out of the annular mass sliding with the radial bearing, and there is a possibility that local wear is generated and durability is reduced. Was.
[0006]
The present invention has been made in view of the above-described problems, and a technical problem thereof is to provide a torque fluctuation absorbing damper that can stably support a pulley by a bearing for a long period of time.
[0007]
[Means for Solving the Problems]
As a means for effectively solving the above-mentioned technical problem, a torque fluctuation absorbing damper according to the invention of claim 1 is a dynamic vibration absorber in which an annular mass body is elastically connected to a hub via a first elastic body. And a coupling portion that elastically connects a pulley to the hub via the second elastic body, wherein the first elastic body is bonded between the annular mass and an axially facing surface of the hub. The pulley is supported by the annular mass via a first bearing, and is supported by the hub via a second bearing.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
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 its axis. The “front side” used in the description of this embodiment is the left side in FIG. 1, that is, the front side of the vehicle, and the “rear side” is the right side in FIG. 1, ie, an internal combustion engine (not shown). Is the side where exists.
[0009]
The torque fluctuation absorbing damper of this embodiment includes a hub 1 attached to a shaft end of a crankshaft of an internal combustion engine, a dynamic vibration absorber 2 provided on the hub 1, a pulley 3 around which a belt is wound, and a crankshaft. And a coupling portion 4 for transmitting the driving torque input to the pulley 3 from the hub 1.
[0010]
The hub 1 is a combination of an outer ring 11, an inner ring 12, and a retainer 13 formed by stamping and pressing a metal plate. A shaft hole 1a through which a crankshaft of an internal combustion engine (not shown) is inserted is formed on the inner periphery. Has been established. Of these, the outermost ring 11 on the rear side includes a disk part 11a on the inner periphery and a rim part 11b extending from the outer end to the front side. The middle inner ring 12 has an inner disk portion 12a stacked in close contact with the inner circumference of the disk portion 11a of the outer ring 11, and an annular step portion 12b protruding from the outer circumference of the inner disk portion 12a toward the front. And a tapered flange portion 12c that forms a gentle conical surface closer to the disk portion 11a of the outer ring 11 toward the outer circumference side. The frontmost retainer 13 is laminated in close contact with the inner peripheral disk portion 12a of the inner ring 12, and has an inner peripheral disk portion 13a whose outer periphery is fitted to the annular step portion 12b of the inner ring 12, and an outer peripheral end thereof. A cylindrical portion 13b extending from the portion to the front side; and a flange portion 13c extending from the front end of the cylindrical portion 13b to the outer peripheral side.
[0011]
The dynamic vibration absorbing portion 2 includes an annular mass body 21 disposed in an inner peripheral space of the rim portion 11b of the outer ring 11 in the hub 1, and an outer peripheral surface of the annular mass body 21 and an inner peripheral surface of the rim portion 11b. And a first elastic body 22 elastically connecting between them. The circumferential natural frequency of the dynamic vibration absorbing unit 2 is determined by the circumferential inertial mass of the annular mass body 21 and the circumferential shear spring constant of the first elastic body 22 so that the torsion angle of the crankshaft is maximized. , That is, the natural frequency of the crankshaft in the circumferential direction.
[0012]
The annular mass body 21 is made of a metal material having a large specific gravity, such as FC, and the first elastic body 22 is made of a rubber-like elastic material having excellent heat resistance, cold resistance and mechanical strength. The dynamic vibration absorbing section 2 sets the outer ring 11 of the hub 1 and the annular mass body 21 concentrically in a predetermined mold, and radially opposes the rim portion 11 b of the outer ring 11 and the annular mass body 21. An uncured rubber material for molding is filled in an annular cavity defined by the mold between the surfaces, and is heated and pressurized, thereby being vulcanized into an annular shape and simultaneously vulcanized and bonded. It is. That is, the annular mass body 21 and the first elastic body 22 constituting the dynamic vibration absorber 2 form a vulcanized molded product integral with the outer ring 11.
[0013]
The pulley 3 is made of a metal material such as FC. The pulley 3 is located on the outer peripheral side of the rim portion 11b of the outer ring 11 of the hub 1 and has a poly-V groove 31a formed on the outer peripheral surface. A front panel portion 32 extending from the front end to the inner periphery of the front side of the rim portion 11b and the dynamic vibration absorbing portion 2 and further retreating to the rear side through an annular step portion 33 on the inner periphery side. It has an inward flange portion 34 formed at the specified position. The inward flange portion 34 is located on the axial front side of the tapered flange portion 12c of the inner ring 12 of the hub 1.
[0014]
Between the pulley body 31 of the pulley 3 and the rim portion 11b of the outer ring 11 of the hub 1, a radial bearing 5 formed of a low-friction coefficient synthetic resin material such as PTFE having excellent wear resistance is interposed. ing. The pulley 3 is concentrically supported by the radial bearing 5 on the outer periphery of the rim portion 11b so as to be relatively displaceable in the circumferential direction.
[0015]
The coupling portion 4 elastically connects the pulley 3 to the inner ring 12 of the hub 1 by a second elastic body 41. More specifically, the second elastic body 41 is made of a rubber-like elastic material having excellent heat resistance, cold resistance and mechanical strength, and is arranged on the inner peripheral side of the annular mass body 21 in the dynamic vibration absorber 2. The rear end is integrally vulcanized and bonded to the tapered flange 12c of the inner ring 12, and the front end is integrally formed with the inward flange 34 of the pulley 3. Vulcanized adhesive.
[0016]
That is, the second elastic body 41 has the inner ring 12 and the pulley 3 set concentrically in a predetermined mold, and the inner ring 12 and the tapered flange portion 12c of the inner ring 12 opposed to each other in the axial direction. An unvulcanized rubber material for molding is filled in an annular cavity defined by the mold between the facing flange portion 34 and the mold, and is heated and pressurized so that it is vulcanized and molded at the same time as vulcanization. It is a vulcanized molded product integrally bonded to the pulley 3 and the inner ring 12 by sulfur bonding.
[0017]
The second elastic body 41 has a required thickness in the radial direction, thereby securing the strength necessary for transmitting torque, and has a required thickness in the connecting direction (axial direction), thereby providing dynamic force. The circumferential shearing spring constant is sufficiently lower than that of the first elastic body 22 in the dynamic vibration absorber 2. Further, the second elastic body 41 has a shaft formed on the outer peripheral side by the tapered flange portion 12c so that the distortion when subjected to shear deformation in the circumferential direction is substantially uniform between the inner peripheral side and the outer peripheral side. The shape is such that the thickness in the direction is large.
[0018]
As understood from the above description, the dynamic vibration absorbing portion 2 and the coupling portion 4 are present on the inner peripheral side of the rim portion 11b. In other words, the pulley main body 31 is connected via the radial bearing 5. The supporting circumference of the supporting rim portion 11b is large, and therefore, a stable supporting force for the pulley 3 is exhibited.
[0019]
The flange portion 13c of the retainer 13 in the hub 1 is located on the front side of the inward flange portion 34 of the pulley 3, and has excellent wear resistance such as PTFE between the opposite flange portions 13c and 34. A thrust bearing 6 formed of a synthetic resin material having a low friction coefficient is interposed. For this reason, the pulley 3 has its inward flange portion 34 sandwiched between the thrust bearing 6 and the second elastic body 41, whereby the axial behavior is restricted.
[0020]
The torque fluctuation absorbing damper having the above configuration includes a vulcanized molded product including the outer ring 11, the annular mass body 21, and the first elastic body 22, the radial bearing 5, the inner ring 12, the pulley 3, and the second elastic body 41. , The thrust bearing 6, and the retainer 13 are arranged concentrically with each other, and the pulley body 31 of the pulley 3 and the rim portion 11 b of the outer ring 11 are fitted via the radial bearing 5. The outer ring 11, the inner ring 12, and the disk portions 11a, 12a, 13a of the retainer 13 are overlapped with each other by abutting the flange 13c of the retainer 13 and the inward flange 34 of the pulley 3 via the thrust bearing 6. It is easily assembled by stacking. Moreover, since the hub 1 includes the outer ring 11, the inner ring 12, and the retainer 13, which are press-formed products of a metal plate, the hub 1 can be provided at low cost.
[0021]
The distortion of the second elastic body 41 received when the twist angle between the hub 1 and the pulley 3 is the same is due to the tapered flange portion 12c of the inner ring 12 of the hub 1 and the inward flange portion 34 of the pulley 3. The larger the thickness in the axial direction becomes, the smaller the thickness becomes. Therefore, in order to ensure the durability of the second elastic body 41, it is not necessary to make the radial dimension so large. Therefore, even in the case where the radial size of the torque fluctuation absorbing damper cannot be made large due to restrictions on the outer diameter of the pulley 3 or the like, the shaft between the inner ring 12 of the hub 1 and the inward flange 34 of the pulley 3 is not required. By taking a sufficient distance in the direction, excellent durability of the second elastic body 41 can be secured. Alternatively, since the outer diameter of the annular mass body 2 and the pulley 3 can be reduced, the size and weight can be reduced.
[0022]
The torque fluctuation absorbing damper is rotated together with the crankshaft when the hub 1 is mounted on the shaft end of the crankshaft of the internal combustion engine. The driving torque of the crankshaft is transmitted from the hub 1 to the pulley 3 via the second elastic body 41 by the coupling unit 4, and further, the belt (not shown) wound around the poly V groove 31 a of the pulley 3. The power is transmitted to a cooling fan and a rotating shaft of an auxiliary machine such as an alternator. At this time, the first elastic body 22 and the second elastic body 41 are protected by the outer ring 11 of the hub 1 from radiant heat of the internal combustion engine existing on the right side in the figure.
[0023]
The internal combustion engine is driven while repeating the intake, compression, explosion, and exhaust strokes, and converts the reciprocating motion of the piston into the rotational motion of the crankshaft. The torque fluctuation is converted into thermal energy by the circumferential deformation of the second elastic body 41 in the coupling portion 4 with a low spring, so that the torque transmitted to the belt is reduced. Is smoothed. At this time, with the relative displacement of the hub 1 and the pulley 3 in the circumferential direction, the radial bearing 5 slides on the outer peripheral surface of the rim portion 11b of the outer ring 11, for example, with low friction, and the thrust bearing 6 moves on the inner side of the pulley 3, for example. It slides with the direction flange 34 with low friction.
[0024]
On the other hand, the dynamic vibration absorber 2 composed of the annular mass body 21 and the first elastic body 22 resonates in the circumferential direction in a frequency range where the torsional angle due to the torsional vibration of the crankshaft is maximized, and the torque due to the resonance is generated. Since the direction of the torque is opposite to the direction of the input vibration, the peak of the torsion angle of the crankshaft can be effectively reduced.
[0025]
Since the pulley 3 is supported on the outer periphery of the hub 1 via the radial bearing 5, concentricity of the pulley main body 31 with respect to the hub 1 is ensured. In addition, since the pulley body 31 on the outermost side of the pulley 3 is supported by the rim portion 11b on the outermost side of the hub 1 via the radial bearing 5, the supporting circumference is large and, therefore, extremely stable. Supported. As a result, the deflection of the pulley 3 during rotation is small, and local wear of the radial bearing 5 due to the unbalanced load is prevented, so that a stable support state of the pulley 4 by the radial bearing 5 can be ensured for a long time. it can.
[0026]
Further, since the rim portion 11b of the hub 1 receives a radial load acting on the pulley body 31 due to the tension of the belt, the first elastic body 22 is not radially compressed by the radial load. For this reason, the degree of freedom in the circumferential direction of the dynamic vibration absorbing section 2 is large, and therefore, an excellent dynamic vibration absorbing effect can be secured.
[0027]
On the other hand, the axial behavior of the pulley 3 is such that the inward flange portion 34 of the pulley 3 is provided with the thrust bearing 6 on the back surface of the flange portion 13c of the retainer 13 in the hub 1 due to the axial compression elasticity of the second elastic body 41. The second elastic body 41 is appropriately compressed in the axial direction as a reaction force, and the axial elastic displacement of the second elastic body 41 itself is regulated. It has excellent durability.
[0028]
【The invention's effect】
As described above, according to the torque fluctuation absorbing damper according to the first aspect of the present invention, the pulley body on the outermost side of the pulley is supported by the rim portion on the outermost side of the hub via the bearing. Therefore, the pulley is extremely stably supported, and the uneven load due to the deflection of the pulley during rotation and the local wear of the bearing due to this are prevented, so that the stable support state of the pulley can be ensured for a long time. In addition, since the first elastic body of the dynamic vibration absorbing portion is not repeatedly compressed in the radial direction, the durability thereof is improved, and an excellent dynamic vibration absorbing effect can be secured.
[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 passing through its axis.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 hub 11 outer ring 11b rim 12 inner ring 12c tapered flange 13 retainer 2 dynamic vibration absorber 21 annular mass 22 first elastic body 3 pulley 31 pulley main body 32 front panel 33 annular step 34 inward flange 4 Coupling part 41 Second elastic body 5 Radial bearing (bearing)
6 Thrust bearing

Claims (1)

A dynamic vibration absorber (2) in which an annular mass body (21) is elastically connected to a hub (1) via a first elastic body (22); and a second elastic body (41) in the hub (1). And a coupling portion (4) elastically connected to the pulley (3) via the first elastic member (22) and the second elastic member (41). ), Wherein the pulley body (31) of the pulley (3) is concentrically supported on the outer peripheral surface of the rim portion (11b) via a bearing (5). Absorption damper.

Images