JP4632044B2 - Torque fluctuation absorbing damper - Google Patents

Description

  The present invention relates to a torque fluctuation absorbing damper that transmits torque from a drive shaft of a rotary device such as a crankshaft of an automobile engine to another rotary device, absorbs fluctuations in the torque, and absorbs resonance of a drive shaft main body.

  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. 2 is a half sectional view showing an example of a torque fluctuation absorbing damper according to the prior art, cut along a plane passing through the shaft center. In FIG. 2, the left side is the front side of the vehicle and the right side is the internal combustion engine of the vehicle. It is the back side where the engine exists. 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.

  The hub 100 is made of a metal material, and is formed concentrically with each other on the boss portion 101 fixed to the crankshaft, the disc portion 102 extending to the outer periphery thereof, and the front side of the disc portion 102. It consists of an inner peripheral cylinder part 103 and a rim part 104. 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 104 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 104 so as to surround the front side and the outer peripheral side of the dynamic damper portion 110, the rim portion 104, and the inner periphery thereof. The synthetic resin bearing 122 interposed between the coupling cylinder part 121a of the pulley 121 located on the front side of the disk part 102 of the hub 100 and the coupling cylinder of the inner circumferential cylinder part 103 of the hub 100 and the pulley 121. The coupling rubber 123 is connected to the portion 121a.

  In addition, a plurality of engagement holes 121c extending in an arc shape with a predetermined length centering on the axis of the pulley 121 are opened at equal phase intervals at positions facing the annular mass body 2 in the front flange portion 121b of the pulley 121. A plurality of engagement pins 113 are projected in the axial direction on the front surface of the annular mass body 2 at a phase interval corresponding to the engagement holes 121c. 121c is loosely fitted to both sides in the circumferential direction with an appropriate clearance, so that the relative displacement in the circumferential direction of the hub 100 and the pulley 121 is limited to a predetermined range to prevent the coupling rubber 123 from being excessively deformed or damaged. Constitutes a stopper.

That is, the torque fluctuation absorbing damper transmits torque input from the crankshaft to the hub 100 to the pulley 121 while absorbing torque fluctuation by the twisting direction shear deformation action of the coupling rubber 123 in the flexible coupling portion 120. Then, the dynamic damper portion 110 composed of the damper rubber 111 and the annular mass body 112 resonates in the torsion direction in the resonance frequency region of the crankshaft, thereby reducing the amplitude peak of torsional vibration due to crankshaft resonance. A function is exhibited (for example, refer to patent documents 1).
Utility model registration No. 2606562

  However, according to the conventional torque fluctuation absorbing damper as described above, the axial gap G exists between the front flange portion 121b of the pulley 121 and the rim portion 104 and the dynamic damper portion 110 of the hub 100. Then, the axial displacement of the pulley 121 accompanied by the axial deformation of the coupling rubber 123 occurs, and the belt drive becomes unstable. As a result, the durability of the belt decreases and the driving sound of the auxiliary machine increases. Such a problem is pointed out.

  The present invention has been made in view of the above points, and a technical problem thereof is to stabilize the belt drive by suppressing the axial displacement of the pulley.

As means for effectively solving the technical problem described above, a torque fluctuation absorbing damper according to the invention of claim 1 includes a disc portion and an inner peripheral cylinder portion and a rim formed concentrically with each other on one axial side thereof. A hub having a portion, a dynamic damper portion having a structure in which an annular mass body is connected to the outer periphery of the rim portion via a damper rubber, a pulley arranged concentrically and relatively rotatable with the hub, and formed on the pulley And a flexible coupling part having a structure in which a coupling cylinder part extending to the inner circumference of the rim part is connected to the inner circumference cylinder part of the hub via a coupling rubber, and the disk part and the disk part along the disk part. thrust bearing between the inner peripheral flange portion formed in the pulley 4 is interposed, the dust lip projecting in the axial direction is provided on the pulley or coupling rubber, the hub, the Das Thrust cover is attached to be close to the lip, the inner peripheral flange portion of the pulley is what being pressed slidably on the thrust bearing in the compression reaction force of the dust lip.

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 frequency range. The flexible coupling part transmits the driving torque input to the hub to the pulley while absorbing torque fluctuations by the twisting shearing action of the coupling rubber. The dust lip provided on the pulley or coupling rubber prevents dust from entering between the thrust cover and the coupling rubber, and the pulley is thrust by the axial compression reaction force caused by the pressure contact with the thrust cover. Since it also acts to press against the bearing, the axial behavior of the pulley is regulated between the thrust bearing and the thrust cover.

  A torque fluctuation absorbing damper according to a second aspect of the present invention is the configuration described in the first aspect, wherein the outer diameter of the thrust cover is larger than the inner diameter of the inner peripheral flange portion of the pulley. In this way, the thrust cover also functions as a means for preventing the pulley from falling off when the coupling rubber is damaged.

  According to the torque fluctuation absorbing damper of the first aspect of the invention, since the axial behavior of the pulley accompanying axial deformation of the coupling rubber that connects the pulley side and the hub side in the radial direction is regulated, the durability of the belt It is possible to prevent deterioration in performance and increase in driving sound of auxiliary equipment.

  According to the torque fluctuation absorbing damper of the second aspect of the present invention, even if the coupling rubber is damaged, the pulley can be prevented from falling off by the thrust cover, so that safety can be improved.

  Hereinafter, a torque fluctuation absorbing damper according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-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. 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.

  Reference numeral 1 in the figure is a hub attached to 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 disc portion 12, the inner peripheral cylindrical portion 13 extending from the position near the inner periphery of the disc portion 12 to the front side, the cylindrical portion 12 extending from the outer peripheral portion of the disc portion 12 to the front side and concentric with the inner peripheral cylindrical portion 13. The rim portion 14 is formed. 11b is a keyway formed in the inner periphery (shaft hole 11a) of the boss part 11.

  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 DD is configured. The annular mass body 2 is manufactured by casting a metal material having a large specific gravity such as iron, and the damper rubber 3 is a rubber-like elastic material excellent in heat resistance, cold resistance and mechanical strength, and vulcanized. Then, it is press-fitted between the rim portion 14 of the hub 1 and the opposed peripheral surface of the annular mass body 2.

  On the outer peripheral surface of the rim portion 14 of the hub 1 and the inner peripheral surface of the annular mass body 2, corresponding concave portions 14 a and convex portions 2 a that meander gently toward the inner peripheral side in the axially intermediate portion are continuous in the circumferential direction. Is formed. For this reason, the damper rubber 3 has a shape that undulates in the radial direction between the rim portion 14 and the annular mass body 2, thereby preventing slippage in the axial direction and the circumferential direction.

  The dynamic damper portion DD 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. This pulley 4 is manufactured by press molding of a metal plate, and is 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 the front end thereof. A front disk portion 42 extending inward on the front side of the (dynamic damper portion DD) and the front side of the rim portion 14 of the hub 1, and from the inner peripheral end thereof toward the rear side along the inner periphery of the rim portion 14. And the inner peripheral flange portion 44 extending from the end on the back side of the connecting cylinder portion 43 to the inner periphery along the front surface of the disk portion 12 of the hub 1. A poly V groove 41a is formed on the outer peripheral surface of the pulley body 41, and an endless belt (not shown) is wound around the pulley main body 41.

  Between the inner peripheral surface of the pulley main body 41 of the pulley 4 and the outer peripheral surface of the annular mass body 2 on the inner peripheral side thereof, a cylindrical synthetic resin material with excellent friction resistance such as PTFE is used. A radial bearing 5 is formed so as to be slidable. In addition, between the back surface of the inner peripheral flange portion 44 of the pulley 4 and the front surface of the disk portion 12 of the hub 1, a flat washer is formed of a synthetic resin material having a low friction coefficient, such as PTFE, having excellent wear resistance. The thrust bearing 6 is slidably interposed.

  In the annular mass body 2, a large diameter portion 2 b is formed on the back side of the mounting position of the radial bearing 5 so as to face the back surface of the pulley body 41 in the axial direction with a slight gap. The thrust bearing 6 is held by a recess 12 a formed continuously in the circumferential direction on the disk portion 12 of the hub 1.

  A sleeve 7 made of a metal tube or the like is press-fitted on the outer peripheral surface of the inner peripheral cylindrical portion 13 of the hub 1. The outer peripheral surface of the sleeve 7 and the coupling cylindrical portion 43 of the pulley 4 are opposed to each other in the radial direction in an annular space surrounded by the inner peripheral cylindrical portion 13, the disk portion 12 and the rim portion 14 in the hub 1. They are connected via a coupling rubber 8 made of a rubber-like elastic material having excellent heat resistance, cold resistance and mechanical strength. 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 is an annular shape defined between the sleeve 7 and the coupling cylinder portion 43 of the pulley 4 by concentrically setting the sleeve 7 and the pulley 4 in a mold (not shown). The cavities are filled with an unvulcanized rubber material, heated and pressurized, and vulcanized and bonded to the sleeve 7 and the connecting cylinder portion 43 simultaneously with the vulcanization molding. In addition, the coupling rubber 8 is subjected to tensile stress due to shrinkage after molding, but by pressing the sleeve 7 into the outer peripheral surface of the rim portion 14 of the hub 1, the sleeve 7 is appropriately expanded in diameter. The tensile stress is eliminated and the required durability is ensured.

  Dustrips 81 projecting in the axial direction are continuously formed in the circumferential direction on the front outer peripheral portion of the coupling rubber 8. On the other hand, the hub 1 is provided with a thrust cover 9, which is manufactured by press molding of a metal plate or the like, and is formed on the inner peripheral surface of the inner peripheral cylindrical portion 13 in the hub 1. The inserted cylindrical portion 91, a pressing flange 92 that expands in a disc shape from the front end thereof, and the front end of the disc portion 12 in the hub 1 that extends from the rear end of the cylindrical portion 91 to the inner peripheral side. It consists of an inward flange 93 abutted against the inner periphery. The inner peripheral end of the inward flange 93 has the same diameter as the shaft hole 11a of the boss portion 11 in the hub 1, and an engagement notch 93a corresponding to the key groove 11b is formed at one place in the circumferential direction. The outer diameter of the pressing flange 92 is formed larger than the inner diameter of the inner peripheral flange portion 44 of the pulley 4, and the dust lip 81 is brought into close contact with the back surface of the pressing flange 92 in an appropriate compressed state. ing.

  A plurality of engagement holes 42 a extending in an arc shape centering on the axis of the pulley 4 are formed in the front disk portion 42 of the pulley 4 at equal phase intervals. On the other hand, a plurality of engaging projections 14b are projected to the front side at equal phase intervals at the front end of the rim portion 14 in the hub 1, and respectively in the circumferential direction on both sides of the engaging holes 42a. It is loosely fitted with appropriate clearance.

  That is, the engagement hole 42a and the engagement protrusion 14b constitute a stopper that limits relative displacement in the circumferential direction of the hub 1 and the pulley 4 to a predetermined range by mutual interference. Further, the front disk portion 42 of the pulley 4 is provided with a cover 82 extending from the coupling rubber 8, and the front opening of the engagement hole 42 a is closed by the cover 82.

  In the assembly 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. When the damper rubber 3 is press-fitted, a coupling agent for increasing the sliding torque is applied to the outer peripheral surface of the rim portion 14 and the inner peripheral surface of the annular mass body 2 or the inner peripheral surface and the outer peripheral surface of the damper rubber 3. It is preferable to apply.

  Further, for example, a radial bearing 5 is mounted on the annular mass body 2 in advance, and a thrust bearing 6 is mounted on the disk portion 12 of the hub 1, and then an integrally molded product including the pulley 4, the coupling rubber 8, and the sleeve 7. The sleeve 7 of the flexible coupling portion FC is press-fitted into the outer peripheral surface of the inner peripheral cylindrical portion 13 of the hub 1, and the pulley body 41 of the pulley 4 is incorporated into the outer periphery of the radial bearing 5. In this assembling process, the engaging protrusion 14b in the hub 1 and the intermediate portion of the engaging hole 42a in the pulley 4 are aligned with each other in the circumferential direction.

  Then, the cylindrical portion 91 of the thrust cover 9 is lightly press-fitted into the inner peripheral surface of the inner peripheral cylindrical portion 13 and temporarily fixed, thereby completing the assembly. When the automobile engine is assembled into the crankshaft, the pressing flange 92 of the thrust cover 9 is fastened by tightening the inward flange 93 together with the boss portion 11 to the shaft end of the crankshaft using a bolt (not shown). Since the dust strip 81 formed on the front outer peripheral portion of the coupling rubber 8 is pressed against and pressed to the back side, the pulley 4 is urged to the back side, and the inner peripheral flange portion 44 is brought into contact with the thrust bearing 6. It is slidably pressed.

  The torque fluctuation absorbing damper according to this embodiment is rotated together with the crankshaft by mounting the boss portion 11 of the hub 1 on the shaft end of the crankshaft of the automobile engine. This is transmitted to a rotating shaft of an auxiliary machine such as a cooling fan or an alternator via a belt (not shown) wound around 41.

  Periodic torque fluctuations that occur in the crankshaft as the engine is driven cause thermal energy to be generated by shearing the coupling rubber 8 in the torsional direction between the sleeve 7 and the coupling cylinder portion 43 of the pulley 4. Since it is converted, the transmission torque to the belt is smoothed. In addition, the dynamic damper portion DD 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. Since the direction is reversed, the peak of the crankshaft twist angle can be effectively reduced.

  When the relative displacement in the circumferential direction of the hub 1 and the pulley 4 reaches a predetermined magnitude due to resonance of the flexible coupling part FC for cranking of the engine or the like or excessive torque input, the engagement on the hub 1 side The mating protrusion 14b and the engagement hole 42a on the pulley 4 side interfere with each other in the circumferential direction. Since the circumferential clearance between the engagement protrusion 14b and the engagement hole 42a is appropriately set in consideration of the allowable circumferential strain of the coupling rubber 8, the coupling rubber 8 Can be effectively prevented from being excessively deformed and the resulting damage.

  Here, since the engagement hole 42a opened in the front disk portion 42 of the pulley 4 is closed by the cover 82 continuous with the coupling rubber 8, dust or the like flying from the front side is blocked by the engagement hole 42a. Does not enter the sliding portions of the radial bearing 5 and the thrust bearing 6. Further, although the back side of the radial bearing 5 is open to the outside, it extends to the outer peripheral side between the back side of the pulley body 41 and the large diameter portion 2b of the annular mass body 2, so that the swing-off action due to centrifugal force is prevented. In addition, since it is not open to the front side, dust or the like is difficult to enter. Therefore, durability of the radial bearing 5 and the thrust bearing 6 can be improved.

  On the other hand, the dust lip 81 formed on the coupling rubber 8 is brought into close contact with the pressing flange 92 of the thrust cover 9 so that dust, muddy water, or the like is generated between the thrust cover 9 and the coupling rubber 8 from the front side. It prevents intrusion. For this reason, deterioration of the operation of the coupling rubber 8 due to accumulation of dust or the like between the thrust cover 9 and the coupling rubber 8 is effectively prevented.

  Even if the coupling rubber 8 is damaged, the engagement protrusion 14b on the hub 1 side and the engagement hole 42a on the pulley 4 side are engaged with each other in the circumferential direction, so that the hub 1 is moved to the pulley 4. Since the drive torque is continuously transmitted, it is possible to avoid a situation where the engine is stopped due to the stop of the auxiliary machine.

  The pressing flange 92 of the thrust cover 9 is in pressure contact with the dust lip 81 formed on the front outer peripheral portion of the coupling rubber 8, and the outer diameter of the pressing flange 92 is larger than the inner diameter of the inner peripheral flange portion 44 of the pulley 4. Because of the large diameter, even if the coupling rubber 8 is broken, the pulley 4 does not fall off to the front side of the hub 1.

  Further, the pulley 4 is between the thrust bearing 6 in which the inner peripheral flange portion 44 is slidably contacted and the pressing flange 92 of the thrust cover 9 in which the dust lip 81 of the coupling rubber 8 is in close contact, The axial displacement is restricted, and the dust lip 81 has an action of pressing the pulley 4 to the back side by the reaction force by being compressed in the axial direction. For this reason, it is possible to suppress the axial vibration of the pulley 4 during driving, and as a result, it is possible to suppress a decrease in durability of the belt and an increase in driving sound of the auxiliary machine.

1 is a cross-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. FIG. 10 is a half cross-sectional view showing an example of a torque fluctuation absorbing damper according to the prior art cut by a plane passing through an axis.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hub 11 Boss part 12 Disk part 12a Concave part 13 Inner peripheral cylinder part 14 Rim part 14a Concave part 14b Engagement protrusion 2 Annular mass 2a Protrusion part 3 Damper rubber 4 Pulley 41 Pulley main body 42 Front disk part 42a Engagement hole 43 Joint cylinder part 44 Inner peripheral flange part 5 Radial bearing 6 Thrust bearing 7 Sleeve 8 Coupling rubber 81 Dustrip 9 Thrust cover 91 Press-fit cylinder part 92 Press flange DD Dynamic damper part FC Flexible coupling part

Claims (2)

A hub (1) having a disc part (12) and an inner peripheral cylindrical part (13) and a rim part (14) concentrically formed on one side in the axial direction thereof, and an outer periphery of the rim part (14) A dynamic damper portion (DD) having a structure in which an annular mass body (2) is connected via a damper rubber (3), a pulley (4) concentrically and relatively rotatable with the hub (1), and the pulley The coupling cylinder part (43) formed in (4) and extending to the inner circumference of the rim part (14) is connected to the inner circumference cylinder part (13) of the hub (1) via a coupling rubber (8). A thrust bearing between the disk part (12) and an inner peripheral flange part (44) formed on the pulley (4) along the disk part (12). (6) is interposed, and the pulley (4) or the coupling go Dust lip projecting in the axial direction (81) is provided in (8), wherein the hub (1), the thrust cover (9) which is closely dust lip (81) is attached, said pulley (4) The torque fluctuation absorbing damper , wherein an inner peripheral flange portion (44) is slidably pressed against the thrust bearing (6) by a compression reaction force of the dust lip (81) .
  The torque fluctuation absorbing damper according to claim 1, wherein the outer diameter of the thrust cover (9) is larger than the inner diameter of the inner peripheral flange portion (44) of the pulley (4).

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