JP2011001975A - Torque fluctuation absorbing damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfy the function capable of preventing any fall of an annular mass body 2, demonstrating a large damping to the large torque fluctuation input in a flexible coupling part FC, and reducing the damping to the constantly input torsional vibration of the small amplitude.SOLUTION: A torque fluctuation absorbing damper includes: a dynamic damper unit D having a structure in which the annular mass body 2 is connected to an outer circumference of a hub 1 via a damper rubber 3; and a flexible coupling part FC having a structure in which a pulley 4 is connected to the hub 1 via a coupling rubber 8. An engagement groove 44 having an end and extending in the circumferential direction is formed in any one of an outer circumferential surface of the annular mass body 2 and an inner circumferential surface of a pulley 4 opposite thereto, and an engagement projection 21 to be engaged in a relatively displaceable manner to both sides in the circumferential direction in the engagement groove 44 is provided on the other. A guide groove 45 is provided, which extends from the position deviated in the circumferential direction from the neutral position of the engagement projection 21 in the engagement groove 44, and guides the insertion of the engagement projection 21 in the engagement groove 44. Parts in a vicinity of both ends in the circumferential direction of the engagement groove 44 extend in an inclined manner in the axial direction with respect to the circumferential direction.

Description

  The present invention relates to a torque fluctuation absorbing damper that is provided on a pulley that is attached to a rotating shaft such as a crankshaft of an automobile engine and that transmits the torque to another rotating device and absorbs torque fluctuation.

  A part of the driving force of an automobile engine is given to an auxiliary device such as an alternator or a water pump from a pulley provided at the tip of the crankshaft via a belt, but the crankshaft is accompanied by torque fluctuation due to each stroke of the engine. Therefore, the pulley is provided with a torque fluctuation absorbing damper for absorbing torque fluctuation and smoothing transmission torque.

  FIG. 17 shows an example of a conventional torque fluctuation absorbing damper. This type of torque fluctuation absorbing damper includes a hub 100 that is attached to a shaft end of a crankshaft of an automobile engine and rotates integrally, and a dynamic damper portion 110 and a flexible coupling portion 120 that are attached to the hub 100. In this figure, the left side is the front side which is the front side of the vehicle, and the right side is the back side where the internal combustion engine of the vehicle is present.

  The hub 100 is made of a metal material, and is fixed to a crankshaft (not shown) at a boss portion 101 having an inner diameter. The dynamic damper portion 110 has a structure in which an annular mass body 112 is attached to the outer periphery of the rim portion 102 of the hub 100 via a damper rubber 111. The coupling portion 120 includes a pulley 121 having a substantially U-shaped cross section extending from the inner peripheral side of the rim portion 102 so as to surround the front side and the outer peripheral side of the dynamic damper portion 110, and the rim portion 102 and the pulley 121. A synthetic resin bearing 122 interposed therebetween and a coupling rubber 123 on the front side of the hub 100 and connecting between the inner diameter cylindrical portion 103 of the hub 100 and the coupling cylindrical portion 121a of the pulley 121 are included.

  In addition, a plurality of engagement holes 121c extending in a circular arc shape with a predetermined length centering on the axis O of the pulley 121 are arranged at equal phase intervals at a position facing the annular mass body 112 in the front flange portion 121b of the pulley 121. A plurality of engagement pins 113 project in the axial direction at the phase interval corresponding to the engagement holes 121c on the front surface of the annular mass body 112, and the engagement pins 113 are engaged with each other. By loosely fitting the holes 121c to both sides in the circumferential direction with an appropriate clearance, the circumferential relative displacement between the hub 100 and the pulley 121 is limited to a predetermined range, and the coupling rubber 123 is not excessively deformed or damaged. It constitutes a stopper to prevent.

  That is, this torque fluctuation absorbing damper transmits the torque input from the crankshaft to the hub 100 to the pulley 121 while absorbing the torque fluctuation by the torsional direction shear deformation action of the coupling rubber 123 in the flexible coupling portion 120. The damping function that reduces the peak of the amplitude of torsional vibration due to resonance of the crankshaft by the dynamic damper portion 110 composed of the damper rubber 111 and the annular mass body 112 resonating in the torsional direction in the resonance frequency region of the crankshaft. (For example, refer to Patent Document 1).

Japanese Patent No. 3155280

  However, according to the torque fluctuation absorbing damper having the above-described configuration, the damper rubber 111 in the dynamic damper portion 110 is press-fitted between the rim portion 102 of the hub 100 and the annular mass body 112. When the slippage in the axial direction is generated on the fitting surface of the damper rubber 111, there is a concern that the annular mass body 112 falls off to the back side (right side in the drawing).

  In addition, the flexible coupling unit 120 desirably exhibits a large attenuation when a large torque fluctuation is input, such as when starting, and attenuates a small torque fluctuation (small amplitude torsional vibration) that is constantly input. However, it is difficult to satisfy both.

  The present invention has been made in view of the above points, and its technical problem is to prevent the annular mass body from falling off, and a large torque fluctuation input to the flexible coupling portion. It is intended to satisfy the function of exhibiting a large damping for a small torsion and a small damping for a small amplitude torsional vibration that is always input.

  As means for effectively solving the above technical problem, a torque fluctuation absorbing damper according to the invention of claim 1 includes a hub and a dynamic damper portion having a structure in which an annular mass body is connected to the outer periphery of the hub via a damper rubber. A pulley disposed concentrically and relatively rotatably with respect to the hub and the annular mass body, and a flexible coupling portion having a structure in which the pulley is connected to the hub via a coupling rubber, and an outer periphery of the annular mass body An end-engaged engaging groove extending in the circumferential direction is provided on one of the surface and the inner peripheral surface of the pulley facing the surface, and the other is engaged in the engaging groove so as to be relatively displaceable on both sides in the circumferential direction. A guide groove that extends from a position shifted in the circumferential direction from the neutral position of the engagement protrusion in the engagement groove and guides the insertion of the engagement protrusion into the engagement groove. But It is what was kicked.

  In the above configuration, the dynamic damper portion reduces the torsional vibration input to the hub by a dynamic vibration absorption effect by resonating in the torsional direction in a predetermined vibration frequency range, and the flexible coupling portion is attached to the hub. The input driving torque is transmitted to the pulley while absorbing torque fluctuations by the torsional direction shear deformation action of the coupling rubber. Further, the engagement protrusion and the engagement groove engaged with each other on both sides in the circumferential direction so as to be relatively displaceable limit the relative displacement in the circumferential direction of the pulley by a large torque fluctuation input to a predetermined range, thereby coupling rubber. It constitutes a stopper that prevents excessive deformation and breakage of the material, and restricts axial displacement of the annular mass body. In addition, the guide groove for enabling the insertion of the engagement protrusion into the engagement groove extends from a position shifted in the circumferential direction from the neutral position of the engagement protrusion in the engagement groove. The function of restricting the axial displacement of the annular mass body due to the engagement of the engagement groove is not impaired.

  According to a second aspect of the present invention, in the torque fluctuation absorbing damper according to the first aspect of the invention, the vicinity of both ends in the circumferential direction of the engaging groove extends in an axial direction with respect to the circumferential direction.

  If comprised in this way, with respect to the small amplitude torque fluctuation input to the flexible coupling portion, the engagement protrusion is displaced in the circumferential direction only at the portion extending in the circumferential direction in the engagement groove, Since the damping is caused only by the internal friction of the coupling rubber, the damping is suppressed to a small value. On the other hand, when the torque fluctuation input to the flexible coupling part exceeds a predetermined value, the engaging protrusion is located near the end of the engaging groove. By interfering with the inclined portion, attenuation due to friction between the two is added, and a large attenuation is obtained.

  According to a third aspect of the present invention, there is provided the torque fluctuation absorbing damper according to the second aspect, wherein a thrust bearing is interposed between the axially facing surfaces of the pulley and the annular mass body, and the engagement grooves are adjacent to both ends in the circumferential direction. Is a direction in which the surface pressure of the thrust bearing and the pulley or the annular mass body is increased by the relative displacement of the engagement groove and the engagement projection accompanying the increase in the circumferential relative displacement amount of the pulley. Is.

  If comprised in this way, when the torque fluctuation input into a flexible coupling part becomes more than predetermined, an engagement protrusion will interfere with the inclination part in the end part vicinity of an engagement groove, and coupling rubber In addition to the internal friction, a damping due to the friction between the engaging protrusion and the engaging groove and a damping due to an increase in the friction of the thrust bearing are added, so that a large damping can be obtained.

  According to the torque fluctuation absorbing damper according to the present invention, the engaging protrusion and the engaging protrusion constituting the stopper for preventing the coupling rubber from being excessively deformed or damaged by engaging with each other in the circumferential direction so as to be relatively displaceable. Since the groove has a function of regulating the axial displacement of the annular mass body, even if the damper rubber in the dynamic damper portion is press-fitted between the hub and the annular mass body, the slippage of the fitting surface of the damper rubber is reduced. This effectively prevents the annular mass body from being displaced in the axial direction and falling off.

  In addition, since the vicinity of both ends in the circumferential direction of the engaging groove extends in an axial direction with respect to the circumferential direction, the attenuation is small with respect to a small amplitude torque fluctuation input to the flexible coupling portion. As a result, excellent vibration insulation is exhibited, and a large torque fluctuation input can be obtained by adding a damping due to friction to a large torque fluctuation input.

BRIEF DESCRIPTION OF THE DRAWINGS The 1st form of the torque fluctuation | variation absorption damper which concerns on this invention is shown, Comprising: The upper half is sectional drawing cut | disconnected and shown by the plane which passes along an axial center, and a lower half is a side view. It is explanatory drawing which shows the relationship between the engaging protrusion in the 1st form, an engaging groove, and a thrust bearing. It is a section perspective view showing some pulleys in the 1st form. It is a section perspective view showing a part of annular mass object in the 1st form. It is a half sectional view showing the assembly process in the first form. It is explanatory drawing which shows the assembly process in a 1st form. It is explanatory drawing which shows the effect | action at the time of the small torque fluctuation | variation input in a 1st form. It is explanatory drawing which shows the effect | action at the time of the big torque fluctuation | variation input in a 1st form. The 2nd form of the torque fluctuation | variation absorption damper which concerns on this invention is shown, Comprising: The upper half is sectional drawing shown by cut | disconnecting in the plane which passes along an axial center, and a lower half is a side view. It is explanatory drawing which shows the relationship between the engaging protrusion in the 2nd form, an engaging groove, and a thrust bearing. It is a section perspective view showing a part of annular mass object in the 2nd form. It is a section perspective view showing some pulleys in the 2nd form. It is a half sectional view showing an assembly process in the second embodiment. It is explanatory drawing which shows the assembly process in a 2nd form. It is explanatory drawing which shows the effect | action at the time of the small torque fluctuation | variation input in a 2nd form. It is explanatory drawing which shows the effect | action at the time of the big torque fluctuation | variation input in a 2nd form. An example of the torque fluctuation absorption damper by a prior art is shown, the upper half is sectional drawing cut | disconnected and shown by the plane which passes along an axial center, and the lower half is a side view.

  Hereinafter, a torque fluctuation absorbing damper according to the present invention will be described in detail with reference to the drawings. 1 to 8 show a first embodiment of a torque fluctuation absorbing damper according to the present invention. In the following description, the “front side” is the left side in FIG. 1 and is the front side of the vehicle, and the “rear side” is the right side in FIG. That is the side.

  First, in FIG. 1, reference numeral 1 denotes a hub attached to a shaft end of a crankshaft (not shown) of an automobile engine. The hub 1 is manufactured by casting a metal material. The hub 1 is a boss portion 11 into which a shaft end of a crankshaft is inserted into an inner peripheral shaft hole 11a, and extends from the boss portion 11 to the outer peripheral side. The disk portion 12 is formed in a cylindrical shape concentric with the inner diameter cylindrical portion 13 and extending from the outer peripheral portion of the disk portion 12 to the front side while extending from the outer peripheral portion of the disk portion 12 to the front side. A rim portion 14.

  An annular mass body 2 is disposed on the outer periphery of the rim portion 14 of the hub 1, and the annular mass body 2 and the rim portion 14 are elastically coupled via a damper rubber 3 so as to be capable of relative displacement in the circumferential direction. Thus, the dynamic damper portion D is configured.

  The annular mass body 2 is manufactured by casting or the like, and includes a front-side small-diameter portion 2a and a back-side large-diameter portion 2b. The damper rubber 3 is vulcanized and molded with a rubber-like elastic material having excellent heat resistance, cold resistance and mechanical strength, and is press-fitted between the outer peripheral surface of the rim portion 14 of the hub 1 and the inner peripheral surface of the annular mass body 2. It has been done.

  The outer peripheral surface of the rim portion 14 of the hub 1 and the inner peripheral surface of the annular mass body 2 meander gently toward the outer diameter side in the axially intermediate portion. Therefore, the damper rubber 3 is connected to the rim portion 14 and the annular mass body 2. In this way, the shape is wavy in the radial direction, so that sliding in the axial direction and the circumferential direction is less likely to occur.

  The dynamic damper portion D forms a spring-mass system that resonates in the torsional direction in a predetermined frequency range. The torsional direction natural frequency (resonance frequency) is a predetermined frequency range in which the torsion angle of the crankshaft is maximized by the circumferential inertial mass of the annular mass 2 and the torsional direction shear spring constant of the damper rubber 3. In other words, it is tuned to match the natural frequency of the crankshaft in the torsional direction.

  Reference numeral 4 is a pulley. The pulley 4 is manufactured by plastic working or the like of a metal plate, and includes a pulley body 41 disposed on the outer peripheral side of the annular mass body 2, and the annular mass body 2 and the damper rubber 3 from its front end. A front disk part 42 extending to the inner diameter side from the front side of (dynamic damper part D) and the front side of the rim part 14 of the hub 1, and from the inner diameter end toward the rear side along the inner circumference of the rim part 14. It consists of a connecting cylinder 43 that extends. A poly V groove 41a is formed on the outer peripheral surface of the pulley main body 41, and an endless belt (not shown) is wound around the pulley main body 41.

  Between the inner peripheral surface of the rim portion 14 on the front side of the disk portion 12 of the hub 1 and the outer peripheral surface of the coupling cylinder portion 43 of the pulley 4 on the inner peripheral side, PTFE (polytetrafluoroethylene) or the like is provided. A radial bearing 5 formed in a cylindrical shape with a synthetic resin material having a low friction coefficient excellent in wear resistance is slidably interposed. In addition, the concave portion formed continuously in the circumferential direction on the back surface of the front disk portion 42 of the pulley 4 was formed into a flat washer shape with a synthetic resin material having a low friction coefficient and excellent wear resistance, such as PTFE. A thrust bearing 6 is held and is slidably in contact with the front end face of the annular mass body 2.

  A sleeve 7 made of a metal tube or the like is press-fitted on the outer peripheral surface of the inner diameter cylindrical portion 13 of the hub 1. And the outer peripheral surface of this sleeve 7 and the coupling cylinder part 43 of the pulley 4 which exists in the outer peripheral side and mutually opposes radial direction are the cups which consist of rubber-like elastic materials excellent in heat resistance, cold resistance, and mechanical strength. They are connected via a ring rubber 8. The coupling rubber 8 transmits the driving torque input from the crankshaft to the hub 1 to the pulley 4 while being smoothed by a shearing action in the circumferential direction. Together with the pulley 4 and the sleeve 7, the flexible coupling 8 Part FC.

  The coupling rubber 8 has an annular cavity that is concentrically set between a sleeve 7 and a pulley 4 in a mold (not shown), and is defined between the sleeve 7 and a coupling cylinder portion 43 of the pulley 4 by closing the mold. In addition, the unvulcanized rubber material is filled and heated and pressurized to be vulcanized and bonded to the sleeve 7 and the connecting cylinder portion 43 simultaneously with the vulcanization molding.

  As shown in FIGS. 2 and 3, the inner peripheral surface of the pulley body 41 in the pulley 4 has an end-engaged engagement groove 44 extending in the circumferential direction, and extends from the engagement groove 44 in the axial direction. A guide groove 45 is formed in the inner peripheral surface of the pulley body 41 so as to open to the end on the back side.

  On the other hand, on the outer peripheral surface of the small-diameter portion 2a of the annular mass body 2 that is in close proximity to the inner peripheral surface of the pulley body 41, as shown in FIG. The engaging protrusion 21 has an axial width slightly smaller than the axial width of the engaging groove 44 on the inner peripheral surface of the pulley body 41, and is loosely fitted to the engaging groove 44 with appropriate clearance on both sides in the circumferential direction. That is, the engagement groove 44 is engaged so as to be relatively displaceable in both sides in the circumferential direction.

  Specifically, the engagement groove 44 forms a circumferential groove 44a extending in parallel with the circumferential direction of the pulley body 41 and an inclination angle θ from both sides in the circumferential direction to the front side in the axial direction with respect to the circumferential direction. The circumferential groove length 44a of the circumferential groove 44a is set to about the upper limit value of the amplitude due to torque fluctuation input in a normal operation state, and the inclined groove 44b on both sides thereof. The circumferential length L2 of the entire engagement groove 44 including the above is set in consideration of the maximum deformation amount of the coupling rubber 8 that is allowed for an input of a large torque fluctuation.

  The guide groove 45 is formed with a circumferential width that allows the engagement protrusion 21 to pass in the axial direction, and is an intermediate position of the engagement groove 44 in the circumferential groove portion 44a, that is, the circumferential groove portion 44a. It communicates with a position shifted by L3 in the circumferential direction with respect to the neutral position P of the engaging projection 21 inside.

  A torque fluctuation absorbing damper having the above-described configuration is manufactured by press-fitting a cylinder-shaped damper rubber 3 between the rim portion 14 of the hub 1 and the annular mass body 2 disposed on the outer periphery thereof to form the dynamic damper portion D. While assembling, an integrally molded product (flexible coupling part FC) comprising the sleeve 7, the coupling rubber 8 and the pulley 4 is molded, the radial bearing 5 and the thrust bearing 6 are mounted on the pulley 4, and the flexible coupling part FC is a hub. 1 is performed.

  In assembling the flexible coupling portion FC into the hub 1, first, the engagement protrusion 21 protruding from the annular mass body 2 is formed in the circumferential groove portion 44 a of the engagement groove 44 formed in the pulley body 41 of the pulley 4. After the alignment in the circumferential direction so as to face the neutral position which is the middle in the circumferential direction, the radial bearing 5 and the sleeve 7 in the flexible coupling portion FC are connected to the rim portion of the hub 1 as shown in FIG. The inner peripheral surface of 14 and the outer peripheral surface of the inner diameter cylindrical portion 13 are press-fitted. Along with this, the small-diameter portion 2a of the annular mass body 2 is inserted into the inner periphery of the pulley body 41 of the pulley 4, in other words, the dynamic damper portion D is connected to the pulley body 41 of the pulley 4 and the front disk portion 42. It goes into the space surrounded by the U-shape with the cylinder part 43.

  However, if the above-described press-fitting operation is continued as it is, the engagement protrusion 21 protruding from the annular mass body 2 interferes with the rear end portion of the pulley body 41, and as shown in FIG. The engagement protrusion 21 and the guide groove 45 are aligned by appropriately twisting and displacing the pulley 4 against the torsional elasticity of the coupling rubber 8. In this way, as the small-diameter portion 2a of the annular mass body 2 is inserted into the inner periphery of the pulley body 41 of the pulley 4, the engagement protrusion 21 moves in the guide groove 45 in the axial direction, and eventually. When the engagement groove 44 is reached, the torsional elasticity of the coupling rubber 8 restores the state before the annular mass body 2 is torsionally displaced, whereby the engagement protrusion 21 is in the circumferential groove 44a in the engagement groove 44. To the neutral position P. At this time, the front end face of the annular mass body 2 is brought into contact with the thrust bearing 6 held by the front disk portion 42 of the pulley 4 to complete the assembly.

  The torque fluctuation absorbing damper having the above-described configuration is rotated together with the crankshaft by being mounted on the shaft end of the crankshaft of the automobile engine at the boss portion 11 of the hub 1, and the drive torque is supplied to the pulley body of the pulley 4. This is transmitted to a rotating shaft of an auxiliary machine such as a cooling fan, a cooling water pump, or an alternator via a belt (not shown) wound around the section 41.

  The dynamic damper portion D composed of the annular mass body 2 and the damper rubber 3 resonates in the circumferential direction in the frequency range where the torsion angle is maximized by the resonance of the crankshaft, and the torque due to the resonance is the direction of the torque of the input vibration. Therefore, the peak of the twist angle of the crankshaft can be effectively reduced by the dynamic vibration absorption effect.

  On the other hand, in the flexible coupling portion FC, the coupling rubber 8 is sheared and deformed in the torsional direction between the sleeve 7 and the coupling cylinder portion 43 of the pulley 4 due to periodic torque fluctuations generated in the crankshaft as the engine is driven. By doing so, it is converted into thermal energy, and the transmission torque to the belt is smoothed.

  Here, with respect to small amplitude torque fluctuations input to the flexible coupling portion FC in a normal operation state, as shown in FIG. In the engaging groove 44 formed on the inner peripheral surface of the main body 41, the circumferential relative displacement is performed only in a narrow range near the neutral position P of the circumferential groove 44a. For this reason, the damping is caused only by the internal friction due to the deformation of the coupling rubber 8 shown in FIG. 1, so that the damping is suppressed to a small level and exhibits excellent vibration insulation.

  In addition, when a large torque fluctuation is input to the flexible coupling portion FC, the relative displacement amount in the torsional direction of the hub 1 and the pulley 4 is increased, and as shown in FIG. When the relative displacement of 21 reaches the inclined groove portions 44b on both sides of the circumferential groove portion 44a, the engagement protrusion 21 to be relatively displaced in the circumferential direction has an inner surface of the inclined groove portion 44b inclined with respect to the circumferential direction. And slides. The axial load generated by this interference acts as a moving force toward the back side of the pulley body 41 and toward the front side of the annular mass 2, so that the surface pressure between the thrust bearing 6 and the annular mass 2 That is, the frictional force increases. Therefore, in addition to the internal friction of the coupling rubber 8, a large damping can be obtained by increasing the friction between the engagement protrusion 21 and the inclined groove 44 b and the friction of the thrust bearing 6.

  For example, when an excessive torque at the time of starting or the like is input and the relative displacement amount in the torsional direction of the hub 1 and the pulley 4 is further increased, the engagement protrusion 21 becomes the end of the engagement groove 44 (the inclined groove portion 44b). Interfere with the part and prevent further displacement. The circumferential length L2 of the engagement groove 44 shown in FIG. 2 is appropriately set in consideration of the maximum deformation amount of the coupling rubber 8 that is allowed for the input of large torque fluctuations. It is possible to effectively prevent excessive deformation of the coupling rubber 8 and damage to the coupling rubber 8 resulting therefrom.

  Further, the guide groove 45 formed to introduce the engaging protrusion 21 into the engaging groove 44 during assembly has a required offset L3 with respect to the neutral position P. The engaging protrusion 21 is normally engaged. Since the engaging groove 44 is near the neutral position P, the engagement of the engaging protrusion 21 and the engaging groove 44 restricts the axial displacement of the annular mass body 2. Therefore, it is possible to effectively prevent the annular mass body 2 from dropping to the back side (right side in the drawing) due to axial slippage on the fitting surface of the damper rubber 3 due to resonance of the dynamic damper portion D or the like.

  That is, the engagement protrusion 21 and the engagement groove 44 not only have a function of preventing excessive deformation of the coupling rubber 8 against an excessive torque input, but also generate a large damping for a large torque fluctuation, and a small amplitude torsion that is always input. For vibration, it has both a function of reducing attenuation and a function of preventing the annular mass body 2 from falling off.

  Next, FIGS. 9 to 16 show a second embodiment of the torque fluctuation absorbing damper according to the present invention.

  As shown in FIG. 9, in the second embodiment, contrary to the first embodiment described above, the engagement groove and the guide groove are provided on the outer peripheral surface of the small-diameter portion 2 a of the annular mass body 2. Engaging protrusions that are engaged with the groove so as to be relatively displaceable in both sides in the circumferential direction are provided on the inner peripheral surface of the pulley body 41 in the pulley 4. Other parts are configured in the same manner as in the first embodiment.

  Specifically, the outer circumferential surface of the small-diameter portion 2a of the annular mass body 2 has an end-engaged engagement groove 22 extending in the circumferential direction and a shaft extending from the engagement groove 22 as shown in FIGS. A guide groove 23 is formed extending in the direction and opened to the front end of the outer peripheral surface of the small-diameter portion 2a of the annular mass 2.

  On the other hand, on the inner peripheral surface of the pulley main body 41 that is in close proximity to the outer peripheral surface of the small-diameter portion 2a of the annular mass body 2, as shown in FIG. The engagement protrusion 46 has an axial width slightly smaller than the axial width of the engagement groove 22 on the outer peripheral surface of the small-diameter portion 2a of the annular mass body 2, and the engagement groove 22 is suitable for both sides in the circumferential direction. It is loosely fitted with a clearance, that is, engaged in the engagement groove 22 so as to be relatively displaceable on both sides in the circumferential direction.

  Specifically, the engagement groove 22 forms an inclination angle θ from the circumferential groove portion 22a extending in parallel with the circumferential direction of the annular mass body 2 and from both sides in the circumferential direction toward the axially rear side with respect to the circumferential direction. And the circumferential length L1 of the circumferential groove portion 22a is set to about the upper limit value of the amplitude due to torque fluctuations inputted in a normal operation state, and the inclined groove portions on both sides thereof are set. The circumferential length L2 of the entire engagement groove 22 including 22b is set in consideration of the maximum deformation amount of the coupling rubber 8 that is allowed for an input of a large torque fluctuation.

  The guide groove 23 is formed with a circumferential width that allows the engagement protrusion 46 to pass through in the axial direction, and is an intermediate position of the engagement groove 22 in the circumferential groove portion 22a, that is, the circumferential groove portion 22a. The engagement protrusion 46 communicates with a position shifted by L3 in the circumferential direction with respect to the neutral position P of the engagement protrusion 46 inside.

  Also in the manufacture of the torque fluctuation absorbing damper having the above-described configuration, the damper rubber 3 formed into a cylindrical shape is press-fitted between the rim portion 14 of the hub 1 and the annular mass body 2 disposed on the outer periphery thereof, so that the dynamic damper portion D is formed. While assembling, an integrally molded product (flexible coupling portion FC) comprising the sleeve 7, the coupling rubber 8 and the pulley 4 is molded, the radial bearing 5 and the thrust bearing 6 are mounted on the pulley 4, and the flexible coupling portion FC is a hub. 1 is performed.

  In assembling the flexible coupling portion FC into the hub 1, first, the engagement protrusion 46 protruding from the pulley body 41 of the pulley 4 is formed in the circumferential groove portion 22 a in the engagement groove 22 formed in the annular mass body 2. After the alignment in the circumferential direction so as to face the neutral position which is the middle in the circumferential direction, the radial bearing 5 and the sleeve 7 in the flexible coupling portion FC are connected to the rim of the hub 1 as shown in FIG. It press-fits into the inner peripheral surface of the portion 14 and the outer peripheral surface of the inner diameter cylindrical portion 13. Along with this, the small-diameter portion 2a of the annular mass body 2 is inserted into the inner periphery of the pulley body 41 of the pulley 4, in other words, the dynamic damper portion D is connected to the pulley body 41 of the pulley 4 and the front disk portion 42. It goes into the space surrounded by the U-shape with the cylinder part 43.

  However, if the above-described press-fitting operation is continued as it is, the engaging protrusion 46 projecting from the pulley body 41 interferes with the front end of the outer diameter portion of the annular mass 2, so that the coupling rubber 8 The engagement projection 46 and the guide groove 23 are aligned by appropriately twisting and displacing the pulley 4 as shown in FIG. In this way, as the small-diameter portion 2a of the annular mass body 2 is inserted into the inner periphery of the pulley body 41 of the pulley 4, the engagement protrusion 46 moves in the guide groove 23 in the axial direction, and eventually. When the engagement groove 22 is reached, the torsional elasticity of the coupling rubber 8 returns to the state before the annular mass body 2 is torsionally displaced, whereby the engagement protrusion 46 is in the circumferential groove 22a in the engagement groove 22. To the neutral position P. At this time, the front end face of the annular mass body 2 is brought into contact with the thrust bearing 6 held by the front disk portion 42 of the pulley 4 to complete the assembly.

  In the torque fluctuation absorbing damper having the above configuration, as shown in FIG. 15, the pulley main body 41 of the pulley 4 has a small amplitude torque fluctuation that is input to the flexible coupling unit FC in a normal operation state. The engagement protrusions 46 provided on the inner peripheral surface are relatively displaced in the circumferential direction only in a narrow range near the neutral position P of the circumferential groove portion 22a in the engagement groove 22 formed on the outer peripheral surface of the annular mass body 2. The For this reason, the damping is caused only by the internal friction due to the deformation of the coupling rubber 8 shown in FIG. 9, so that the damping is suppressed to a small level and exhibits excellent vibration insulation.

  Further, when a large torque fluctuation is input to the flexible coupling portion FC, the relative displacement amount of the hub 1 and the pulley 4 in the torsion direction increases, and as shown in FIG. When the relative displacement of 46 reaches the inclined groove portions 22b on both sides of the circumferential groove portion 22a, the engagement protrusions 46 that are to be displaced relatively in the circumferential direction have the inner surfaces of the inclined groove portions 22b inclined with respect to the circumferential direction. And slides. The axial load generated by this interference acts as a moving force toward the back side of the pulley body 41 and toward the front side of the annular mass 2, so that the surface pressure between the thrust bearing 6 and the annular mass 2 That is, the frictional force increases. Therefore, in addition to the internal friction of the coupling rubber 8, a large damping can be obtained by increasing the friction between the engagement protrusion 46 and the inclined groove 22 b and the friction of the thrust bearing 6.

  For example, when an excessive torque at the time of starting or the like is input and the relative displacement amount in the torsional direction of the hub 1 and the pulley 4 is further increased, the engagement protrusion 46 becomes the end of the engagement groove 22 (the inclined groove portion 22b). Interfere with the part and prevent further displacement. The circumferential length L2 of the engagement groove 22 shown in FIG. 10 is appropriately set in consideration of the maximum deformation amount of the coupling rubber 8 that is allowed for an input of a large torque fluctuation. It is possible to effectively prevent excessive deformation of the coupling rubber 8 and damage to the coupling rubber 8 resulting therefrom.

  Further, the guide groove 23 formed to introduce the engaging protrusion 46 into the engaging groove 22 during assembly has a required offset L3 with respect to the neutral position P. The engaging protrusion 46 is normally engaged. Since it is near the neutral position P of the joint groove 22, the axial displacement of the annular mass body 2 is restricted by the engagement of the engagement protrusion 46 and the engagement groove 22. Therefore, it is possible to effectively prevent the annular mass body 2 from dropping to the back side (right side in the drawing) due to axial slippage on the fitting surface of the damper rubber 3 due to resonance of the dynamic damper portion D or the like.

  That is, even in this embodiment, the engagement protrusion 46 and the engagement groove 22 are not only excessively deformed by the coupling rubber 8 against excessive torque but also have a large attenuation for large torque fluctuations and are always input. For a small amplitude torsional vibration, it has both a function of reducing attenuation and a function of preventing the annular mass body 2 from falling off.

1 Hub 2 Annular Masses 21 and 46 Engaging Protrusions 22 and 44 Engaging Grooves 22a and 44a Circumferential Grooves 22b and 44b Inclined Grooves 23 and 45 Guide Groove 3 Damper Rubber 4 Pulley 41 Pulley Body 5 Radial Bearing 6 Thrust Bearing 7 Sleeve 8 Coupling rubber D Dynamic damper part FC Flexible coupling part

Claims (3)

  A hub, a dynamic damper portion having a structure in which an annular mass body is connected to the outer periphery of the hub via a damper rubber, a pulley disposed concentrically and relatively rotatable with the hub and the annular mass body, and the pulley connected to the hub. A flexible coupling portion connected via a ring rubber, and an end-engaging engagement groove extending in the circumferential direction on one of the outer circumferential surface of the annular mass body and the inner circumferential surface of the pulley facing the annular mass body; An engaging projection is provided on the other side so as to be relatively displaceable in both sides in the circumferential direction within the engaging groove, and is shifted in the circumferential direction from the neutral position of the engaging projection in the engaging groove. A torque fluctuation absorbing damper, characterized in that a guide groove is provided which extends from a position and guides the insertion of the engagement protrusion into the engagement groove.   The torque fluctuation absorbing damper according to claim 1, wherein the vicinity of both ends in the circumferential direction of the engaging groove extends while being inclined in the axial direction with respect to the circumferential direction.   Thrust bearings are interposed between the axially opposed surfaces of the pulley and the annular mass body, and the inclination of the engagement groove in the vicinity of both ends in the circumferential direction is engaged with the engagement groove as the circumferential relative displacement of the pulley increases. The torque fluctuation absorbing damper according to claim 2, wherein a surface pressure of the thrust bearing and the pulley or the annular mass body is increased by a relative displacement of a protrusion.

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