JP2019065904A - Pulley with isolation - Google Patents

Abstract

To provide a pulley with an isolation capable of improving durability, and capable of easily adjusting shock absorption in a case where driving force is transmitted from a pulley part side connected to a motor generator to a hub connected to a crank shaft.SOLUTION: An isolator rubber is arranged between a hub 10 and a pulley body 20, a first stopper 33 is provided in the hub 10 so as to project radially outward, and a second stopper 35 is provided in the pulley body 20 so as to project radially inward. In the first stopper 33, a main cushion rubber 36a is arranged. The main cushion rubber 36a is configured to transmit to the hub 10 rotational torque applied to the pulley body 20, as the pulley body 20 is displaced in a rotational direction and held between the first stopper 33 and the second stopper 35.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an isolation pulley that transmits the driving force of a drive-side rotating shaft to a driven-side rotating shaft through a belt while isolating torque fluctuation caused by a combustion stroke during engine operation.

  In an internal combustion engine mounted on a vehicle or the like, that is, in an engine, pulleys are used to transmit the driving force of the crankshaft to various main components such as a generator and a compressor via a belt such as a V-belt. It is attached to each of the crankshaft and the main shaft of accessories. A belt is stretched around the outer circumferences of both pulleys, and the pulley mounted on the crankshaft, which is the rotating shaft, is on the driving side, and the pulley mounted on the main shaft, which is the rotating shaft of accessories, is on the driven side. .

  In recent years, vehicles having an idling stop function for stopping an engine when stopping for a short time by a signal or the like and then restarting the engine (hot start) are increasing for the purpose of fuel efficiency improvement. Among such engines of vehicles, there are those which also use a generator (alternator), which is a generator, as a motor, and such a system is an ISG (Integrated Starter Generator) system or BAS (Belt Alternator / Starter). It may be called a method. Hereinafter, in the present specification, the ISG method will be uniformly referred to. In this idling stop mechanism of the ISG system, power is applied from the battery to the generator at engine restart to make the generator function as a starter motor. The driving force of the starter motor is transmitted to the crankshaft via the belt to start the engine. Hereinafter, a generator that can function as a motor is referred to as a motor generator. In this case, the main shaft of the motor generator is on the drive side, and the crankshaft of the engine is on the driven side.

  Furthermore, there is an ISG hybrid vehicle that assists the driving force of the engine by strengthening the motor generator used only for restarting the engine.

  In this ISG hybrid vehicle, when the crankshaft is driven by the engine, the motor generator is driven with the crankshaft to which the driving force is applied by the engine as the drive side, and when the crankshaft is driven by the motor generator: The crankshaft is driven with the motor generator to which power is applied from the battery as the drive side. When the motor generator is used as a drive source, the torque of the motor generator can be added to the engine torque to assist the crankshaft or start the engine.

  In general, low-frequency large vibration (hereinafter referred to as start-up vibration) generated between the crankshaft and auxiliary equipment at the time of engine start, and resonance of the intrinsic value of the crankshaft during steady operation of the engine Pulsating vibration (hereinafter referred to as torque fluctuation) which is superimposed on the rotation of the crankshaft due to a combustion stroke in the cylinder of the engine which is caused by resonance vibration (hereinafter referred to as steady resonance vibration) and which is superimposed on rotation of the crankshaft. There is.

  As a countermeasure against these vibrations, a pulley provided with an anti-vibration function is used. In order to transmit the driving force between the crankshaft of the engine and the main shaft of the auxiliaries such as the motor generator, belts are attached to the pulleys mounted respectively on the crankshaft and the main shaft of the auxiliaries. The pulley mounted on the crankshaft of the engine has a hub mounted on the crankshaft and a pulley portion on which the belt is mounted. A dynamic damper consisting of an annular mass and a damper rubber is incorporated between them, and this dynamic damper absorbs stationary resonance vibration. An isolator rubber is disposed between the hub and the pulley portion, and elastic deformation of the isolator rubber absorbs torque fluctuation superimposed on the rotation of the crankshaft, and at the same time, the rotation of the smoothed crankshaft, ie, the crankshaft The driving force is transmitted to the pulley portion by the isolator rubber, and further transmitted to the supplementary sheet through the belt.

  Examples of pulleys mounted on a crankshaft of an engine include those described in Patent Documents 1 to 3.

JP, 2006-17234, A Japanese Patent Application Publication No. 2007-71263 JP 2008-57553 A

  In the pulley described in Patent Document 1, a dynamic vibration absorbing portion is disposed between the hub and the pulley portion, and a rubber coupling that extends in the radial direction between the axial direction both end portions of the pulley portion and the hub A department is provided. In the pulley described in Patent Document 2, in addition to the annular mass body and the damper rubber, a coupling rubber is provided between the hub and a small-diameter coupling cylindrical portion inside the damper rubber. The coupling rubber transmits the input torque transmitted to the hub by circumferential shear deformation to the pulley portion while smoothing it. Further, in the pulley described in Patent Document 3, a cylindrical elastic body extending in the axial direction is attached as an isolator rubber between the radial cover portion integrated with the pulley portion and the radial direction portion of the hub. ing. The cylindrical elastic body blocks the rotational fluctuation so that the torque fluctuation of the rotating shaft is not transmitted to the pulley portion.

  In the pulley as described above, when a large driving force is applied to the hub by the crankshaft and the speed difference occurs between the hub and the pulley portion, the hub and the pulley portion are largely displaced in the circumferential direction, The isolator rubber deforms significantly in the circumferential direction. When torque fluctuation is absorbed by shear deformation of the isolator rubber, an excessive speed difference is generated between the hub and the pulley portion due to abnormal vibration or the like, and when a displacement amount exceeding the fracture limit is applied to the isolator rubber, the isolator rubber But there is a risk that the pulley may come off. Therefore, in the range of normal use, the spring constant of the isolator rubber is set such that the amount of displacement between the hub and the pulley main body greatly falls below the breaking limit of the isolator rubber. Further, an engagement mechanism is provided so that transmission of the driving force to the auxiliary machine is not interrupted in a short period even if breakage occurs in the isolator rubber due to abnormal vibration or the like. As an engagement mechanism, there is one in which an arc-shaped elongated hole extending in the circumferential direction is provided in the pulley main body, and a protrusion protruding from the elongated hole is provided in the hub.

  Also, as described above, in the normal use range, the protrusion is designed not to abut on the end face of the long hole of the hub, but the fracture limit of the isolator rubber so that the isolator rubber is not broken even in abnormal vibration. Some designs are designed such that the projections provided on the hub abut against the elongated holes of the pulley body to prevent the isolator rubber from breaking.

  In this case, the deformation stroke of the isolator rubber, that is, the stroke until the projection provided on the hub abuts on the elongated hole of the pulley body can not be taken large, so only a slightly larger torsional vibration is generated momentarily. Also, the contact between the projection and the long hole is likely to occur. Not only does this contact cause a loud impact sound to cause the driver to feel uneasy, but if this contact is repeated, metal abrasion powder is generated from the contact portion. If the generated wear powder enters the sliding portion inside the pulley, the sliding portion may be worn to affect the life of the pulley, which may reduce the durability of the pulley. In an automobile engine, when the engine is started, the above-mentioned vibration at start-up occurs because the crankshaft passes through the resonance point of the isolator rubber while the rotational speed of the crankshaft rises to the normal use range. It may be deformed significantly and the above-mentioned contact may occur.

  In addition, when using the above-mentioned pulley in a vehicle having an ISG idling stop function that starts a crankshaft by a motor generator or a vehicle of an ISG hybrid system, the auxiliary machinery etc. Because the driving force is transmitted from the pulley part side connected to the motor generator to the hub connected to the crankshaft so as to apply the driving force to the crank shaft that is heavier than that of the motor generator, the isolator rubber of the pulley It will be deformed to the direction maximum displacement. Therefore, the pulleys used in these systems may need to be replaced periodically depending on the use conditions, and improvement in durability is strongly desired.

  On the other hand, in order to prevent the protrusion provided on the hub from impactingly contacting the long hole provided on the pulley portion, it is conceivable to arrange a cushion rubber between the inner wall surface of the long hole and the protrusion. . In that case, since it is necessary to endure the contact generated each time the motor generator is driven, the soft cushion rubber can not be adopted, and the shock absorbing force is insufficient. In addition, since hard cushion rubber is likely to generate rubber abrasion powder due to the impactal abutment of the projections, if this rubber abrasion powder enters the sliding portion, the durability of the pulley may be reduced.

  The object of the present invention is to improve the durability, and also to easily adjust the shock absorbing property when the driving force is transmitted from the pulley unit side connected to the motor generator to the hub connected to the crankshaft. It is to provide a pulley with a ration.

  The isolated pulley according to the present invention comprises a hub attached to a rotating shaft, a pulley body on which a belt is mounted, an isolator rubber disposed between the hub and the pulley body, and a radially outward direction on the hub The pulley is provided in a circumferential space formed between at least two first stoppers provided in a protruding manner, and the first stopper and a first stopper circumferentially adjacent to the first stopper. It is provided to be projected to one side in the circumferential direction on at least one of a second stopper provided protruding from the main body, and the first stopper and the second stopper, and the pulley main body is displaced in the rotational direction to By being sandwiched between a first stopper and the second stopper, the pulley body transmits a rotational torque applied from a drive source to the hub. It has a rubber, a.

  An isolator rubber is disposed between the hub and the pulley body, and a main cushion rubber is disposed between a first stopper provided on the hub and a second stopper provided on the pulley body. The main cushion rubber is sandwiched between the first stopper and the second stopper when the pulley main body is displaced in the rotational direction and the first stopper tries to abut on the second stopper. The rotational torque (driving force) applied to the pulley body is transmitted to the hub via the cushion rubber. At this time, the isolator rubber can cooperate with the main cushion rubber to buffer an impact at the contact between the second stopper and the first stopper. Thus, by combining the compression spring of the main cushion rubber and the shear spring of the isolator rubber, excessive deformation of the isolator rubber can be prevented, and shocking abutment between the second stopper and the first stopper can be buffered. Furthermore, reliable rotational torque transmission can be performed. In addition, when the hub receives rotational torque in the rotational direction and the isolator rubber is displaced within a range in which the main cushion rubber is not sandwiched between the first stopper and the second stopper, the isolator rubber functions independently. be able to. Thereby, the isolator rubber is not affected by the main cushion rubber for the absorption of torque fluctuations applied to the hub. Therefore, according to the present invention, when rotational torque is transmitted from the pulley main body side to the hub side, the rotational torque can be reliably transmitted without excessive elastic deformation of the isolator rubber, and from the hub side to the pulley main body side When the rotational torque is transmitted, the isolator rubber can well absorb the torque fluctuation, so the torque fluctuation can be well absorbed and a highly durable isolation pulley can be obtained.

It is the perspective view seen from one side of the pulley with isolation which is one embodiment. FIG. 2 is a side view of the isolation pulley shown in FIG. 1; It is a side view on the other side of FIG. 1 in the pulley with isolation. It is the sectional view on the AA line in FIG. It is the BB sectional drawing in FIG. (A) is an enlarged side view which shows a part of FIG. 2, (B) is an enlarged side view which shows a part of pulley with isolation provided with the sub cushion rubber which is a modification. It is a spring characteristic diagram of a pulley with isolation. (A) is a side view showing a relative torsion between the hub and the pulley main body when the motor generator is on the drive side, and (B) is a relative relation between the hub and the pulley main body when the crankshaft is on the drive side It is a side view showing a state of twisting. It is the perspective view seen from the one side of the pulley with an isolation which is other embodiment. It is sectional drawing in FIG. 9 cut | judged in the same position as the AA line cross section in FIG.

  Hereinafter, embodiments of the present invention will be described in detail based on the drawings. The pulley P with isolation, as shown in FIGS. 1 to 4, includes a hub 10 and a pulley body 20, and the hub 10 has a boss 11 as a mounting portion attached to the rotation shaft and a diameter larger than the boss 11 The cylindrical portion 12 is integrated with the end portion of the boss 11 via the radial direction portion 13. A radially outwardly projecting protrusion 14 is integrally provided at an axially central portion of the cylindrical portion 12, and an annular rim 15 is integrally provided at an outer peripheral portion of the protrusion 14.

  An annular mass body 17 is mounted on the radially outer side of the rim portion 15 via an annular damper rubber 16. The damper rubber 16 is formed of a vulcanized rubber or the like, and is press-fitted between the outer peripheral surface of the rim portion 15 and the inner peripheral surface of the annular mass 17 so as to be coaxial with the rim portion 15. A journal bearing 18 made of resin is disposed between the annular mass 17 and the pulley body 20, and the damper rubber 16 and the annular mass 17 cause resonance due to the resonance of the intrinsic value of the crankshaft during steady operation of the engine. A dynamic damper is configured to reduce vibration, that is, steady-state resonance vibration. The thrust bearing 21 is abutted against the outer peripheral surface of the end face of the annular mass 17.

  As shown in FIGS. 1 and 4, pulley grooves 23 and 24 are provided on the outer peripheral surface of the pulley body 20, and belts can be attached to the pulley grooves 23 and 24 of the pulley body 20. The pulley grooves 23, 24 are formed by a plurality of annular grooves.

  The boss 11 is coaxial with the central axis O and attached to a rotating shaft (not shown), and the tip of the rotating shaft protrudes into the space 19 in the cylindrical portion 12. A nut (not shown) screwed to the tip of the rotation shaft is disposed in the space 19 and abuts against the inner surface of the radial portion 13, and the rotation shaft is fastened to the boss 11.

  As shown in FIG. 4, the inner sleeve 25 is fitted to the cylindrical portion 12 of the hub 10, and the outer sleeve 26 is fitted to one end side of the pulley body 20. An isolator rubber 27 is disposed radially extending between the inner sleeve 25 and the outer sleeve 26. The inner peripheral surface of the isolator rubber 27 is vulcanized and bonded to the inner sleeve 25, and the outer peripheral surface of the isolator rubber 27 is the outer sleeve 26. It is vulcanized and bonded to The isolator rubber 27 is preferably made of a softer rubber than the damper rubber 16, that is, a rubber having a small elastic modulus.

  As shown in FIG. 4, the isolator rubber 27 has a disk shape extending radially between the inner sleeve 25 and the outer sleeve 26, but a radially extending cover member is provided inside the pulley body 20. A ring member having a disk member extending in the radial direction may be provided on the outer peripheral surface of the cylindrical portion 12, and a cylindrical isolator rubber extending in the axial direction may be provided between the cover member and the disk member.

  As shown in FIGS. 4 and 5, a stopper ring 31 is fitted to the other end side of the cylindrical portion 12 of the hub 10. As shown in FIG. 5, the stopper ring 31 includes an annular portion 32 and a plurality of first stoppers 33 projecting radially outward from the annular portion 32. Six first stoppers 33 are provided in the annular portion 32 at regular intervals in the circumferential direction, and the first stoppers 33 are circumferentially provided between the first stoppers 33 adjacent to each other in the circumferential direction. An extending space or circumferential space 34 is formed.

  On the other end side of the pulley body 20, a plurality of second stoppers 35 projecting radially inward are provided. Six second stoppers 35 are provided on the pulley main body 20, and each second stopper 35 projects into the circumferential space 34 between the first stoppers 33, and Opposite in the circumferential direction. As described above, the first stopper 33 and the second stopper 35 are respectively provided in the same number. The number of the respective stoppers 33 and 35 is not limited to six, and can be any number. Furthermore, the number may not be the same.

  The opposing surfaces 33 a and 33 b are provided on both sides in the circumferential direction of the first stopper 33, and the opposing surfaces 35 a and 35 b are provided on both sides in the circumferential direction of the second stopper 35. As shown in FIG. 6A, the opposing surfaces 33a face the opposing surfaces 35a, and the opposing surfaces 33b face the opposing surfaces 35b, and are perpendicular to the central axis O of the hub 10, as shown in FIG. And is the radial or radial surface of the hub 10.

  The isolated pulley P can be used to transmit a driving force, that is, a rotational torque between the motor generator as an accessory and the engine. In that case, the hub 10 is attached to the crankshaft of the engine, and the belt attached to the pulley body 20 is stretched around the pulley of the motor generator. The rotational direction of the pulley P with isolation is a clockwise direction as shown by arrows in FIGS. 5 and 6. When the rotational torque applied from the motor generator using the motor generator as a drive source is transmitted to the crankshaft, the pulley body 20 is on the drive side, the hub 10 is on the driven side, and the pulley body 20 to the hub 10 The driving force or rotational torque is transmitted. At this time, the opposing surface 35 a of the second stopper 35 becomes the opposing surface on the driving side, and the opposing surface 35 a approaches the opposing surface 33 a of the first stopper 33 with elastic deformation of the isolator rubber 27.

  On the other hand, when the rotational torque applied from the crankshaft by the engine as a drive source is transmitted to the motor generator, the hub 10 is on the driving side and the pulley body 20 is on the driven side. The driving force or rotational torque is transmitted. At this time, the opposing surface 33 b of the first stopper 33 is the opposing surface on the driving side, and the opposing surface 33 b approaches the opposing surface 35 b of the second stopper 35 with elastic deformation of the isolator rubber 27.

  A main cushion rubber 36a is fixed to an opposing surface 33a on one circumferential side of the first stopper 33, and the main cushion rubber 36a protrudes in the circumferential direction toward the opposing surface 35a. The auxiliary cushion rubber 36b is fixed to the opposing surface 33b on the other circumferential direction side of the first stopper 33, and the auxiliary cushion rubber 36b protrudes in the circumferential direction toward the opposing surface 35b. It is preferable that the main cushion rubber 36 a and the sub cushion rubber 36 b be made of rubber harder than the isolator rubber 27.

  The main cushion rubber 36a has a proximal end 37 fixed to the opposing surface 33a by vulcanization adhesion and the like, and a distal end 38 integrally formed with the proximal end 37 and protruding from the proximal end 37 in the circumferential direction doing. The proximal end 37 is tapered such that the radial thickness gradually decreases in the projecting direction, and the distal end 38 also tapers such that the radial thickness gradually decreases from the proximal end 37 toward the distal end. As described above, in the present embodiment, the main cushion rubber 36 a is a two-step taper in which the taper angle is different between the base end portion 37 and the tip end portion 38.

  The proximal end portion 37 and the distal end portion 38 have a tapered shape in which the thickness in the radial direction gradually decreases in the projecting direction, but the axial thickness of the proximal end portion 37 and the distal end portion 38 gradually proceeds in the projecting direction The tapered shape may be reduced, and both the radial thickness and the axial thickness may be gradually reduced in the projecting direction. That is, one or both of the thickness in the radial direction and the thickness in the axial direction of the proximal end portion 37 and the distal end portion may be tapered in such a manner as to gradually decrease in the projecting direction. The secondary cushion rubber 36b shown in FIG. 6A has substantially the same shape as the primary cushion rubber 36a. The proximal end portion 37 may not be tapered, and only the distal end portion 38 may be tapered.

  As shown in FIG. 4, a damper rubber 16 is disposed at an axially central portion of the cylindrical portion 12 of the hub 10, and an isolator rubber 27 is disposed at one axial end side of the hub 10. A main cushion rubber 36a and a sub cushion rubber 36b are disposed on the other end side. That is, the isolator rubber 27, the main cushion rubber 36a, and the auxiliary cushion rubber 36b are disposed at both axial ends of the cylindrical portion 12 via the damper rubber 16.

  The clockwise rotation of the rotating shaft on which the hub 10 is mounted is in the normal rotation direction, and the isolated pulley P is not transmitting power without any load, that is, the isolator rubber 27 rotates clockwise or counterclockwise. When not displaced, as shown in FIG. 6A, the facing surface 33a of the first stopper 33 and the facing of the second stopper 35 facing in the counterclockwise direction with respect to the facing surface 33a. A distance between the stoppers in the circumferential direction between the surface 35a is a first distance A between the stoppers, and an opposing surface 33b of the first stopper 33 and a second opposing surface 33b in the clockwise direction. Assuming that the distance between stoppers in the circumferential direction between the opposing surface 35 b of the stoppers 35 is a distance B between second stoppers, the distance A between first stoppers is smaller than the distance B between second stoppers (A <B ).

  Also, until the main cushion rubber 36a is sandwiched between the first stopper 33 and the second stopper 35 when the pulley main body 20 is on the drive side and torque is transmitted from the pulley main body 20 to the hub 10 That is, the twist angle of the isolator rubber 27 until the tip of the main cushion rubber 36a contacts the opposing surface 35a of the second stopper 35 is taken as a first twist angle α. On the other hand, until the auxiliary cushion rubber 36 b is sandwiched between the first stopper 33 and the second stopper 35 when the hub 10 is on the driving side and torque is transmitted from the hub 10 to the pulley body 20, That is, when the twist angle of the isolator rubber 27 until the tip of the auxiliary cushion rubber 36b contacts the opposing surface 35b of the second stopper 35 is the second twist angle β, the twist angle α is smaller than the twist angle β ( α <β).

  The torsion angle α is at least set larger than the range in which the first stopper 33 swings around the central axis O when the isolator rubber 27 absorbs torque fluctuations during steady operation of the engine, and more preferably by vibration at start-up The first stopper 33 is set larger than the range in which the first stopper 33 swings around the central axis O. The angle is smaller than the twist angle at which the isolator rubber 27 breaks. On the other hand, the torsion angle β is set to be larger than the torsion angle α and, in some cases, larger than the angle which becomes the breaking limit of the isolator rubber 27.

  FIG. 6 (B) is an enlarged side view showing a part of the isolation pulley P provided with the auxiliary cushion rubber 36b which is a modified example. The auxiliary cushion rubber 36b has a circumferential length shorter than that shown in FIG. 6 (A). In this case, the case where the first stopper 33 and the second stopper 35 abut on each other via the sub cushion rubber 36 b than in the case where the sub cushion rubber 36 b of FIG. 6A is provided on the first stopper 33. Although the shock absorbing property is inferior, since a large torsion angle β can be obtained, it can be used even in an engine having a large start vibration and torque fluctuation.

  The isolator rubber 27 is elastically deformed when the pulley P with the isolation is rotated to generate a speed difference between the hub 10 and the pulley body 20, and torque fluctuation is superimposed on the rotation of the rotation shaft on the drive side. Block this torque fluctuation, and the smooth rotation is transmitted to the driven side rotation shaft. When the isolator rubber 27 is elastically deformed, the hub 10 and the pulley main body 20 are twisted in the circumferential direction, so that one of the two opposing surfaces 33 a and 33 b of the respective first stoppers 33 is the both of the second stoppers 35. It approaches one of the opposing surfaces 35a, 35b, and the other separates from the other of the opposing surfaces 35a, 35b.

  When the pulley body 20 is on the drive side, for example, in FIGS. 5 and 6, the hub 10 is rotationally driven clockwise via the isolator rubber 27 by the pulley body 20, and the second stopper 35 is the first stopper. Approach 33. Thereby, the main cushion rubber 36a provided on the opposing surface 33a of each first stopper 33 relatively approaches toward the second stopper 35, and the sub cushion rubber provided on the opposing surface 33b. 36 b is relatively separated from the second stopper 35.

  When the pulley body 20 on the drive side rotates relative to the hub 10 and exceeds the torsion angle α, the leading end of the main cushion rubber 36a abuts on the second stopper 35, and the main cushion rubber 36a is the first stopper It is inserted between 33 and the second stopper 35 to be elastically deformed. At this time, since the main cushion rubber 36a abuts on the second stopper 35 with a margin before the fracture limit of the isolator rubber 27, it is possible to alleviate the abutment shock while preventing the fracture of the isolator rubber 27. Thereby, the durability of the isolator rubber 27 can be improved.

  Here, the main cushion rubber 36a has a tapered tip portion 38, and can make rapid superposition of driving force gentle. Furthermore, the main cushion rubber 36a has a two-step taper of the tapered base end portion 37 and the tip end portion 38, so that the base end portion 37 supports a certain load or more even if the initial contact is softened. So there is no fear of buckling. By combining the tapered shapes of the proximal end portion 37 and the distal end portion 38, the transmission characteristics of the driving force from the pulley main body 20 to the hub 10 can be adjusted.

  On the other hand, when the hub 10 attached to the crankshaft of the engine is on the drive side, the pulley body 20 is rotationally driven clockwise by the hub 10 via the isolator rubber 27, and the first stopper 33 is the second Approach the stopper 35. Thereby, the sub-cushion rubber 36b provided on the opposing surface 33b of each first stopper 33 approaches toward the second stopper 35, and the main cushion rubber 36a provided on the opposing surface 33a is Away from the second stopper 35.

  When the drive side hub 10 rotates relative to the pulley body 20 and the displacement is within the breaking limit of the isolator rubber 27, torque fluctuation of the crankshaft during steady operation of the engine is blocked by the isolator rubber 27; A smooth rotation is transmitted to the pulley body 20. It is natural that the engine is designed so as not to exceed the breaking limit of the isolation rubber 27 during steady operation of the engine. However, when the velocity difference between the hub 10 and the pulley main body 20 exceeds the breaking limit of the isolator rubber 27 and breakage of the isolator rubber 27 occurs due to the abnormality of the engine or the accessories, the driving force for the accessories In order to prevent a loss of transmission, the first stop 33 abuts the second stop 35 over the twist angle β. At this time, the presence of the sub-cushion rubber 36b can suppress the generation of the contact noise and the wear of the first stopper 33 and the second stopper 35. Although the rotational motion of the hub 10 can be transmitted to the pulley main body 20 when the isolator rubber 27 breaks even if the auxiliary cushion rubber 36b is not provided, the abrasion powder adversely affects other devices or causes an impact. Since the first and second stoppers may be broken, it is preferable to provide the auxiliary cushion rubber 36b.

  In an ISG hybrid vehicle, when power is generated by an engine, a motor generator is driven with a crankshaft as a drive side rotation shaft. On the other hand, when the crankshaft is driven with the main shaft of the motor generator as the drive side rotation shaft, the rotation torque of the motor generator can be superimposed on the engine torque to assist or start the engine. As described above, when driving the crankshaft with the motor generator as the drive side, the speed of the rotation shaft of the motor generator is increased to the engine startable rotation speed within several hundred milliseconds. Therefore, when the motor generator is on the drive side, the difference between the rotational speed of the motor generator and the rotational speed of the driven crankshaft increases for a very short time, but the twist of the isolator rubber 27 due to the difference in rotational speed is also , Is suppressed by the main cushion rubber 36a.

  When the pulley P with isolation is mounted on an IGS hybrid vehicle, the isolator rubber 27 can be used to drive the crankshaft even if the crankshaft drives the motor generator. In steady state operation, the isolator rubber 27 is roughly maintained in a state of being displaced in the direction in which α increases and β decreases. Therefore, it is preferable to set the twist angles α and β in consideration of the engine output, the motor generator output, and the spring constant of the isolator rubber.

  FIG. 7 is a spring characteristic diagram of the pulley P with isolation, showing spring characteristics of the isolator rubber 27 alone, the main cushion rubber 36a alone and the sub cushion rubber 36b alone, and a state in which these rubbers work together, ie, iso The spring characteristic diagram of the pulley P with a ration (Hereinafter, it is called a rubber assembly here.) Is shown. In FIG. 7, the horizontal axis indicates the twist angle θ between the hub 10 and the pulley body 20, and the vertical axis indicates the generated torque of each rubber. When the twist angle θ is 0, as shown in FIGS. 5 and 6, when there is no speed difference between the hub 10 and the pulley body 20 and no load is generated on the driven side, that is, The time when the pulley with isolation P is not transmitting power is shown.

  The thin line A indicates the generated torque of the isolator rubber 27 with the change of the twist angle θ. As indicated by the thin line A, the isolator rubber 27 has a characteristic that the generated torque changes substantially linearly in the range of the twist angle θ. In other words, the isolator rubber is used in a linear range in which the rubber itself is unlikely to deteriorate even if it is repeatedly subjected to torsional displacement. Here, [+] and [-] of the torsion angle θ in FIG. 7 indicate, in the pulley P shown in FIG. The time when the rotating shaft attached to 10 becomes the driven side and the pulley body 20 relatively rotates in the left direction is indicated as "-".

  The thick line B indicates the generated torque of the main cushion rubber 36a and the auxiliary cushion rubber 36b, and when the pulley body 20 is on the drive side, the main cushion is used when the twist angle θ of the pulley body 20 with respect to the hub 10 exceeds a predetermined twist angle α. The rubber 36a abuts against the second stopper 35, and the generated torque rises sharply to the "+" side after passing through the contact position, that is, the compression start angle a of the main cushion rubber 36a. That is, the displacement of the pulley body 20 is strongly restricted from this angle. On the other hand, when the rotation axis attached to the hub 10 is on the drive side, the secondary cushion rubber 36b abuts on the first stopper 33 when the twist angle θ of the hub 10 with respect to the pulley body 20 exceeds a predetermined twist angle β. When the contact position, that is, the compression start angle b of the auxiliary cushion rubber 36b is passed, the generated torque rises sharply to the “−” side. That is, the displacement of the hub 10 is strongly restricted from this angle. As shown by the thick line B, the main cushion rubber 36a and the sub cushion rubber 36b have a tapered shape at the tip end portion 38 and the base end portion 37, so that the rising of the generated torque at the initial stage of contact is relatively gentle. As the displacement progresses, a stronger generated torque is generated.

  An alternate long and short dash line C indicates the generated torque of the rubber assembly. The generated torque of the rubber assembly increases when the torsion angle α is exceeded. Moreover, it will become large when it exceeds twist angle (beta).

  The torsion angle β in the above spring characteristic diagram is an angle at which the sub-cushion rubber 36b is inserted within the range in which the isolator rubber is not broken, but the actual pulley P with isolation is more than the breaking limit of the isolator rubber. The twist angle β may be increased. In this case, after the isolator rubber is broken, the first stopper and the second stopper abut on each other via the sub cushion rubber.

  FIG. 8 shows a power transmission mechanism in which an isolated pulley P is attached to a crankshaft 41 of an engine and a belt 44 is stretched around an accessory pulley 43 and a pulley main body 20 attached to a main shaft 42 of a motor generator. . In the figure, the rotational torque applied by the drive side is indicated by a thick arrow, and the rotational torque received by the driven side is indicated by a thin arrow.

  FIG. 8A shows a state in which the driving force is transmitted to the crankshaft 41 which is the driven shaft side via the belt 44 with the main shaft 42 of the motor generator rotating in the clockwise direction as the driving shaft side. At this time, the second stopper 35 abuts on the main cushion rubber 36 a due to the speed difference between the main shaft 42 and the crankshaft 41 at the time of startup of the motor generator. As described above, the main cushion rubber 36a does not deform the isolator rubber 27 more than the maximum displacement allowed in terms of durability, and the driving force is absorbed by the main cushion rubber 36a to the crankshaft 41. It can be transmitted. Thereby, the durability of the isolator rubber 27 can be improved.

  In FIG. 8 (B), the isolator rubber 27 is broken due to the abnormality of the engine and the auxiliary machinery, and the transmission of the driving force of the crankshaft 41 by the isolator rubber 27 is lost. The attached first stopper 33 is rotated in the clockwise direction, and the torsion angle β is obtained. At this time, the crankshaft 41 was on the drive shaft side, and the first stopper 33 mounted on the hub 10 was in contact with the second stopper 35 via the sub-cushion rubber 36 b and was bridged over the pulley body 20 The driving force can be transmitted to the main shaft 42 of the motor generator on the driven shaft side via the belt 44.

  FIG. 9 shows a perspective view seen from one side of an isolation pulley P according to another embodiment, and FIG. 10 is a cross-sectional view in FIG. 9 cut at the same position as the A-A cross section in FIG. Indicates

  In the present embodiment, the second stopper 35 is formed between the first stopper and the side surface of the flange portion 22 extending in the inner diameter direction on the other end side of the pulley body 20. It protrudes in the space part 34, and is provided. The other configuration is the same as that of the embodiment described above. The flange portion 22 may be integrally formed with the pulley main body 20, or may be separately formed and then fixed to the pulley main body 20 by a bolt or the like.

  The present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the pulley P with isolation described above, the main cushion rubber 36a and the sub cushion rubber 36b are provided on all the first stoppers 33, but the main cushion rubber may be used for any number of the first stoppers 33. It is sufficient to provide 36a and a secondary cushion rubber 36b. Further, the main cushion rubber 36 a and the sub cushion rubber 36 b may be provided on the contact surface of the second stopper 35 in the circumferential direction. Alternatively, one of the main cushion rubber 36 a and the sub cushion rubber 36 b may be provided on the first stopper 33, and the other may be provided on the second stopper 35.

DESCRIPTION OF REFERENCE NUMERALS 10 hub 11 boss 12 cylindrical portion 15 rim portion 16 damper rubber 17 annular mass 20 pulley main body 22 flange portion 27 isolator rubber 32 annular portion 33 first stoppers 33a, 33b facing surface 34 circumferential space portion 35 second stopper 35a , 35b Opposite surface 36a Main cushion rubber 36b Secondary cushion rubber 37 Base end 38 Tip 41 Crankshaft 42 Main shaft 43 Accessory pulley 44 Belt

Claims (9)

A hub attached to the rotating shaft,
A pulley body on which a belt is mounted;
An isolator rubber disposed between the hub and the pulley body;
At least two first stoppers provided radially outward on the hub;
A second stopper provided to protrude from the pulley main body in a circumferential space formed between the first stopper and a first stopper adjacent to the first stopper in the circumferential direction;
At least one of the first stopper and the second stopper is provided so as to protrude to one side in the circumferential direction, and the pulley main body is displaced in the rotational direction so that the first stopper and the second stopper A main cushion rubber for transmitting rotational torque applied from a drive source to the hub by the pulley main body being sandwiched therebetween;
With an isolated pulley.   The pulley with isolation according to claim 1, wherein the main cushion rubber has a tapered tip portion in which the radial thickness and / or the axial thickness gradually decrease in the projecting direction.   The pulley with isolation according to claim 2, wherein the main cushion rubber is integrally provided between the first stopper or the second stopper and the tip, and has a radial thickness and / or an axial direction. An isolated pulley having a tapered proximal end whose thickness gradually decreases in the projecting direction.   The pulley with isolation according to any one of claims 1 to 3, wherein opposed surfaces of the first stopper and the second stopper that face each other via the main cushion rubber are respectively made of the hub Isolation pulley with radial surface. The pulley with isolation according to any one of claims 1 to 4.
When the isolation pulley is in a no-load state, the circumferential distance between the first stopper and the second stopper is equal to the distance between the second stopper and the first stopper. And an isolation pulley which is smaller than the distance between the second stoppers in the circumferential direction.   The isolation pulley according to any one of claims 1 to 5, further comprising a sub-cushion rubber provided on at least one of the first stopper and the second stopper so as to protrude to the other side in the circumferential direction. Isolation pulley.   The pulley with isolation according to claim 6, wherein the main cushion rubber is sandwiched between the first stopper and the second stopper when rotational torque is transmitted from the pulley body to the hub. The second cushion rubber is sandwiched between the first stopper and the second stopper when rotational torque is transmitted from the hub to the pulley body. Isolation pulley smaller than the second twist angle of the isolator rubber up to.   The pulley with isolation according to any one of claims 1 to 7, wherein a plurality of the first stopper and the second stopper are provided.   The pulley with isolation according to any one of claims 1 to 8, wherein the rim provided on the hub comprises an annular mass mounted via an annular damper rubber.

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