JP5800131B2 - Torque fluctuation absorbing damper - Google Patents

Description

  The present invention relates to a torque fluctuation absorbing damper in which a pulley that transmits torque from an output shaft of a rotary drive device such as an internal combustion engine to another rotating device is provided with a mechanism that absorbs fluctuations in transmission torque.

  A part of the driving force generated in the internal combustion engine of an automobile 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 wound around the pulley. Since the shaft is rotated with torque fluctuation due to each stroke of the internal combustion engine, the pulley is provided with a torque fluctuation absorbing mechanism for absorbing torque fluctuation and smoothing transmission torque. FIG. 3 shows a typical prior art of such a torque fluctuation absorbing damper.

  That is, this type of torque fluctuation absorbing damper includes a hub 100 that is attached to the shaft end of a crankshaft of an internal combustion engine for an automobile and rotates integrally, and a dynamic damper portion 110 and a flexible coupling portion 120 that are attached to the hub 100. Is provided.

  The dynamic damper portion 110 has a structure in which a first elastic body 111 is press-fitted between an outer cylinder portion 101 of the hub 100 and an annular mass body 112 disposed on the outer periphery thereof. In addition, the coupling portion 120 extends from the pulley 121 supported on the outer periphery of the annular mass body 112 via a radial bearing 123, and the back side of the hub 100 (the right side in FIG. 3) extends in the inner diameter direction. The thrust bearing 122 interposed between the existing inward flange portion 121a and the outer cylinder portion 101 of the hub 100, and the inner diameter side of the outer cylinder portion 101 of the hub 100 from the inner diameter of the inward flange portion 121a of the pulley 121. A radial bearing 123 interposed between the extending sleeve portions 121b, a sleeve 103 fitted to the outer peripheral surface of the inner cylinder portion 102 of the hub 100, and a sleeve portion 121b of the pulley 121 are vulcanized and bonded. A second elastic body 124.

  In other words, this type of torque fluctuation absorbing damper absorbs torque fluctuation from the crankshaft to the hub 100 while absorbing torque fluctuations in the flexible coupling portion 120 by the torsional direction shear deformation action of the second elastic body 124. 121, and a dynamic damper portion 110 composed of a spring-mass system composed of the first elastic body 111 and the annular mass body 112 resonates in the torsional direction in the resonance frequency range of the crankshaft, whereby the crankshaft It exhibits a vibration damping function that dynamically absorbs resonance (see Patent Document 1).

Utility model registration No. 2606562

  However, in the conventional torque fluctuation absorbing damper, when the internal combustion engine is started or stopped, the change in frequency of torque fluctuation accompanying the change in the rotation speed of the crankshaft passes through the resonance point of the flexible coupling unit 120. Therefore, there is a problem that slip occurs between the pulley 121 that swings greatly due to an increase in torque fluctuation at this time and a belt (not shown) wound around the pulley 121. When such a belt slip occurs, not only an abnormal noise called “belt squeal” is generated, but also there is a concern that the durability of the belt is lowered and the running is hindered.

  Further, by reducing the torsional direction spring constant of the second elastic body 124 in the flexible coupling portion 120, it is possible to improve the torque fluctuation absorption performance within the normal rotation range of the internal combustion engine. The durability of the second elastic body 124 is lowered and easily damaged. Therefore, in order to prevent the second elastic body 124 from being excessively deformed in the torsional direction, a stopper mechanism 125 having a pin and hole loose fitting structure for limiting the circumferential relative displacement amount of the hub 100 and the pulley 121 is provided. There is also a problem that the structure is complicated and the cost is increased.

  Further, in the state where the circumferential relative displacement between the hub 100 and the pulley 121 is regulated by the stopper mechanism 125 in the resonance region of the flexible coupling part 120, the characteristic is different from the free state where the circumferential relative displacement is not regulated. It will be different.

  In addition, by lowering the torsional spring constant of the second elastic body 124, the change in the frequency of torque fluctuation when starting or stopping the internal combustion engine passes through the resonance point of the flexible coupling unit 120. In other words, it cannot be avoided, that is, the resonance point of the flexible coupling part 120 only moves to the low frequency side, so that it is not a fundamental measure for effectively preventing belt slip.

  Furthermore, by incorporating a one-way clutch (not shown) into the conventional torque fluctuation absorbing damper, it is possible to cancel the sudden increase in torque fluctuation when the torque fluctuation frequency passes through the resonance point of the flexible coupling unit 120. In this case, there is a problem that the structure becomes complicated and the cost becomes high.

  The present invention has been made in view of the above points, and a technical problem thereof is torque that can transmit torque while absorbing fluctuations and that can prevent occurrence of belt slip. It is to provide a variable absorption damper.

As a means for effectively solving the above technical problem, a torque fluctuation absorbing damper according to the invention of claim 1 is provided between a hub and a radially opposed surface of a pulley disposed concentrically near the hub. A radial bearing is slidably interposed, and a first thrust bearing is slidably interposed between a flange provided on the hub and an axially opposed surface of the pulley. An elastic body is disposed on the opposite side to the flange in the axial direction, and a second thrust bearing is slidably interposed between the elastic body and the axially opposed surface of the pulley, and the elastic body moves in the twisting direction. a possible shear deformation, is fitted on the hub via a holder, by an axial urging force to impart a frictional force on the sliding surface of the first thrust bearing and the second thrust bearing It is an butterfly.

  In the above configuration, the pulley is supported by the hub in a state in which the pulley is constrained with respect to the axial direction and the radial direction via the radial bearing, the first thrust bearing, and the second thrust bearing and is relatively rotatable. The normal input torque is transmitted between the hub and the pulley by the friction force of the first thrust bearing, the second thrust bearing and the radial bearing, and the normal torque fluctuation is absorbed by the deformation of the elastic body in the torsional direction. When the input torque fluctuation exceeds the sum of the sliding torque due to the frictional force applied to the first thrust bearing and the second thrust bearing by the axial biasing force of the elastic body and the sliding torque of the radial bearing. Causes slippage in the first thrust bearing, the second thrust bearing and the radial bearing.

  According to a second aspect of the present invention, in the torque fluctuation absorbing damper according to the first aspect, the sum of the slip torques of the first thrust bearing and the second thrust bearing and the radial bearing is the slip torque between the pulley and the belt. It is set smaller.

According to the torque fluctuation absorbing damper according to the present invention, torque transmission between the hub and the pulley is normally performed by the frictional force of the first thrust bearing, the second thrust bearing, and the radial bearing, and the input torque fluctuation is If the sum of the frictional force (sliding torque) applied to the first thrust bearing and the second thrust bearing by the axial biasing force of the elastic body and the sliding torque of the radial bearing exceeds the first thrust bearing, Since the two thrust bearings and radial bearings slip and the rotation of the pulley is smoothed by coulomb damping, no means for regulating the relative displacement in the torsional direction of the hub and the pulley is required, and torque fluctuations Damage to the elastic body due to the increase can be prevented. Further, it is possible to easily set the biasing force of the elastic body, and consequently the frictional force of the sliding surfaces of the first thrust bearing and the second thrust bearing, depending on the position where the holder is fitted to the hub.

  Also, if the sum of the sliding torques of the first thrust bearing and the second thrust bearing and radial bearing is set smaller than the sliding torque between the pulley and the belt, the first thrust bearing, By causing slippage in the second thrust bearing and the radial bearing, it is possible to prevent belt slip, occurrence of “belt squealing”, and reduction in durability of the belt.

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 an axis O. FIG. It is sectional drawing of the state before the assembly which shows preferable embodiment of the torque fluctuation | variation absorption damper which concerns on this invention cut | disconnected by the plane which passes along the axial center O, and is shown. It is sectional drawing which cuts and shows an example of the torque fluctuation absorption damper by a prior art by the plane which passes along the axis O.

  Hereinafter, a preferred embodiment of a torque fluctuation absorbing damper according to the present invention will be described with reference to FIGS. 1 and 2. The “front side” used in the following description is the left side in the figure, that is, the front side of the vehicle, and the “back side” is the right side in the figure, that is, there is an internal combustion engine (not shown). That is the side.

  Reference numeral 1 denotes a hub attached to a shaft end of a crankshaft (not shown) of an automobile internal combustion engine. The hub 1 is manufactured by casting a metal material or the like, and includes an inner cylinder portion 11 fixed to the crankshaft, an intermediate portion 12 extending from the front end portion to the outer diameter side, It has an outer cylinder portion 13 extending from the outer diameter end portion to the back side, and an outer diameter flange 14 extending from the front end portion in the outer diameter direction. Reference numeral 11a is a key groove formed in the inner peripheral shaft hole of the inner cylindrical portion 11, and the outer diameter flange 14 corresponds to the "flange provided on the hub" described in claim 1. It is.

  A pulley 2 is concentrically disposed close to the outer peripheral side of the hub 1. The pulley 2 is manufactured by casting a metal material or the like, and includes a pulley body 21 having a poly V groove 21a formed on the outer peripheral surface, and an outer diameter flange of the hub 1 extending from the inner periphery to the inner diameter direction. 14, a supported flange portion 22 that is axially opposed from the back surface side, and further extends from the inner peripheral end portion of the supported flange portion 22 toward the back surface side to the outer peripheral surface of the outer cylinder portion 13 of the hub 1 and the radial direction. And a supported cylinder portion 23 facing the surface. A belt (not shown) is wound around the outer peripheral surface of the pulley body 21 in which the poly V groove 21a is formed.

  The radial bearing 3 is slidable between the outer peripheral surface 13a of the outer cylindrical portion 13 of the hub 1 and the inner peripheral surface 23a of the supported cylindrical portion 23 of the pulley 2 that is radially opposed to the outer peripheral portion 13a. Intervened in a state. The outer peripheral surface 13a and the inner peripheral surface 23a correspond to the “radially opposed surfaces” recited in claim 1. The radial bearing 3 is made of a synthetic resin material such as PTFE (polytetrafluoroethylene) having excellent slidability and wear resistance, and is formed into a cylindrical shape. That is, the pulley 2 is formed of the radial bearing 3. And is supported in the radial direction so as to be rotatable relative to the outer cylindrical portion 13 of the hub 1.

  Between the end surface 14a on the back surface side of the outer diameter flange 14 of the hub 1 and the end surface 22a on the front surface side of the supported flange portion 22 facing the surface 14a in the axial direction from the back surface side, the first thrust bearing 4 is provided. It is in a slidable state. The end surfaces 14a and 22a correspond to the “facing surface in the axial direction of the flange provided on the hub and the pulley” recited in claim 1. The first thrust bearing 4 is made of a synthetic resin material such as PTFE having excellent slidability and wear resistance, and is formed into a flat washer shape.

  The elastic body 5 is disposed on the opposite side of the outer diameter flange 14 of the hub 1 in the axial direction as viewed from the supported flange portion 22 of the pulley 2, that is, on the back side of the supported flange portion 22. The elastic body 5 is inserted into the space on the back side of the outer diameter flange 14 of the hub 1 from the fitting cylinder portion 51a press-fitted and fitted to the inner peripheral surface of the outer cylinder portion 13 of the hub 1 and the rear end portion thereof. A metal holder 51 composed of a disk part 51b that expands in a radial direction toward the disk, and a flat washer that is on the front side of the disk part 51b in the holder 51 and faces the supported flange part 22 of the pulley 2 in the axial direction. The retainer 52 and an elastic body 53 provided integrally between the retainer 52 and the disk portion 51 b of the holder 51. The elastic body 53 is made of a rubber-like elastic material (rubber material or synthetic resin material having rubber-like elasticity) having excellent heat resistance, cold resistance and mechanical strength.

  That is, the elastic body 5 has a holder 51 and a retainer 52 concentrically set in a mold (not shown), and an annular cavity defined by clamping the mold between the holder 51 and the retainer 52. The elastic body 53 is integrally vulcanized and molded (vulcanized and bonded) to the holder 51 and the retainer 52 by filling an unvulcanized rubber material and heating and pressurizing.

  The second thrust bearing 6 is slidable between the front end surface 52a of the retainer 52 of the elastic body 5 and the rear end surface 22b of the supported flange portion 22 of the pulley 2 facing the retainer 52. Intervene. Note that the end faces 52a and 22b correspond to “an axially facing surface of the elastic body and the pulley” described in claim 1. The second thrust bearing 6 is made of a synthetic resin material such as PTFE having excellent slidability and wear resistance, and is formed into a flat washer shape.

Elastic body 53 of the elastic member 5, the axial direction length L ₁ in the assembled state shown in FIG. 1, is shorter than the axial length L ₀ in the state prior to assembly shown in FIG. 2, i.e. As the elastic body 53 in the elastic body 5 is precompressed, an axial urging force is applied as a reaction force thereof, and the retainer 52 is pressed against the second thrust bearing 6 by the axial urging force. Yes. For this reason, the second thrust bearing 6, the supported flange portion 22 of the pulley 2, and the first thrust bearing 4 are pressed against the outer diameter flange 14 of the hub 1, whereby the first thrust bearing 4 and A predetermined frictional force is applied to the sliding surface of the second thrust bearing 6.

  Further, the sum of the sliding torque of the first thrust bearing 4 and the second thrust bearing 6 applied by the urging force of the elastic body 5 and the sliding torque of the radial bearing 3 is transferred from the hub 1 to the pulley 2 from the normal rotation. It is set to be larger than the normal torque to be transmitted and smaller than the sliding torque between the outer peripheral surface of the pulley main body 21 in which the poly V groove 21a is formed and a belt (not shown) wound around this.

  The radial bearing 3 and the first thrust bearing 4 may be integrally continuous with each other.

  In the torque fluctuation absorbing damper having the above configuration, the first thrust bearing 4, the radial bearing 3, the pulley 2, and the second thrust bearing 6 are arranged on the outer periphery of the outer cylinder portion 13 of the hub 1 from the state shown in FIG. By inserting and fitting the fitting cylinder part 51a of the holder 51 in the elastic body 5 into the inner peripheral surface of the outer cylinder part 13 of the hub 1, it is assembled in the state shown in FIG. As a result, the pulley 2 is restrained in the radial direction via the radial bearing 3 on the outer periphery of the outer cylindrical portion 13 of the hub 1 in a state in which the pulley 2 is allowed to rotate relative to the hub 1, and the outer diameter of the hub 1. The flange 14 is constrained to be clamped in the axial direction with the elastic body 5 via the first thrust bearing 4 and the second thrust bearing 6.

  In the above-described assembly, the amount of compression of the elastic body 53, in other words, the axis of the elastic body 53 is determined by the amount of axial insertion of the fitting cylinder 51a of the holder 51 with respect to the inner peripheral surface of the outer cylinder 13 of the hub 1. Since the direction biasing force is determined, it is possible to easily set the sliding torque by the frictional force of the sliding surfaces of the first thrust bearing 4 and the second thrust bearing 6.

  The torque fluctuation absorbing damper is rotated together with the crankshaft by attaching the inner cylinder portion 11 of the hub 1 to the shaft end of the crankshaft (not shown). The torque during normal rotation of the crankshaft is supplied from the hub 1 through the elastic body 5, the first thrust bearing 4, the second thrust bearing 6 and the radial bearing 3 to the first thrust bearing 4 and the second thrust. It is transmitted to the supported flange portion 22 of the pulley 2 by the frictional force of the bearing 6 and the radial bearing 3, and further, via a belt wound around the pulley body 21 of the pulley 2, a cooling water circulation pump, an alternator, and a cooling fan Is transmitted to the rotating shaft of the auxiliary machine.

  Since the crankshaft is rotated with torque fluctuation caused by the drive of the internal combustion engine, the hub 1 attached to the crankshaft is inputted with vibrations in the torsional direction to cause a swing. In such a normal torque fluctuation in the normal rotation range, the elastic body 53 of the elastic body 5 is repeatedly subjected to shear deformation in the twisting direction (circumferential direction), so that the kinetic energy due to the torque fluctuation is changed to the elastic body main body. Since it is consumed as heat energy by the internal friction generated with the deformation of 53, the rotation of the pulley 2 is smoothed, that is, the swing of the pulley 2 is suppressed.

  Here, when the fluctuation of the input transmission torque increases beyond the sum of the sliding torques of the first thrust bearing 4 and the second thrust bearing 6 and the radial bearing 3, the first thrust bearing 4 at that time. Since the second thrust bearing 6 and the radial bearing 3 slip, the kinetic energy due to torque fluctuation is consumed as thermal energy, and coulomb damping is absorbed to absorb the fluctuation of the transmission torque. That is, the swinging of the pulley 2 is suppressed. Further, since the shearing of the elastic body 5 in the torsional direction (circumferential direction) applied to the elastic body 53 by the slippage of the second thrust bearing 6 is also suppressed, the elastic body 53 is damaged due to excessive deformation and durability. Therefore, a means for restricting the relative displacement in the torsional direction of the hub 1 and the pulley 2 becomes unnecessary, and the structure can be simplified.

  Further, since the sum of the slip torques of the first thrust bearing 4 and the second thrust bearing 6 and the radial bearing 3 is set to be smaller than the slip torque between the pulley 2 and the belt, input of excessive torque fluctuations. Sometimes the first thrust bearing 4, the second thrust bearing 6 and the radial bearing 3 are caused to slip so that the swing of the pulley 2 is suppressed, so in all regions from the rotational speed 0 to the normal rotational region, It is possible to prevent the occurrence of belt slip and the occurrence of “belt squealing” and a decrease in belt durability.

1 Hub 13 Outer cylinder part 14 Outer diameter flange (flange)
2 Pulley 21 Pulley body 22 Supported flange part 23 Supported cylinder part 3 Radial bearing 4 First thrust bearing 5 Elastic body 51 Holder 52 Retainer 53 Elastic body main body 6 Second thrust bearing

Claims (2)

A radial bearing is slidably interposed between a hub and a radially opposed surface of a pulley disposed concentrically near the hub, and between a flange provided on the hub and an axially opposed surface of the pulley. The first thrust bearing is slidably interposed, and an elastic body is arranged on the opposite side of the flange in the axial direction when viewed from the pulley, and between the elastic body and the axially opposed surface of the pulley, Two thrust bearings are slidably interposed, and the elastic body is shearable in a torsional direction and is fitted to the hub via a holder, and the first thrust is applied by an axial biasing force. A torque fluctuation absorbing damper, wherein a frictional force is applied to a sliding surface of the bearing and the second thrust bearing.   2. The torque fluctuation absorbing damper according to claim 1, wherein a sum of slip torques of the first thrust bearing and the second thrust bearing and the radial bearing is set smaller than a slip torque between the pulley and the belt.

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