JP2016180459A - Rotational fluctuation absorption pulley - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotational fluctuation absorption pulley which prevents dust from entering into a bearing slide part without depending on a seal lip.SOLUTION: A rotational fluctuation absorption pulley includes: a hub 1 attached to a rotary shaft; a sensing plate 2 attached to the hub 1 and having a detected part 25 for detecting rotation; a pulley body 4 supported by a hub 1 side member through a radial bearing 3; and coupling rubber 5 which connects the pulley body 4 with the hub 1 side member so that the pulley body 4 and the hub 1 side member may be displaced relative to each other in a circumferential direction. An outer periphery part of the sensing plate 2 is bend toward the outer periphery side of the pulley body 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rotation fluctuation absorbing pulley that is attached to a shaft end of a crankshaft of an engine and transmits torque and absorbs the rotation fluctuation, and particularly relates to a rotation detection pulley that includes a rotation detection sensing plate.

  The rotation fluctuation absorbing pulley includes a hub that rotates together with the crankshaft of the engine, a pulley body that is disposed on the outer peripheral side of the hub and on which a belt is wound, and an annular shape that elastically connects the hub side and the pulley body side. A coupling rubber and a dynamic damper having a structure in which an annular mass body is elastically and concentrically connected to the outer periphery of the hub via an annular damper rubber. Some have a sensing plate made of a metal disk for detecting a crank angle or detecting the number of revolutions.

  In other words, the rotational fluctuation absorbing pulley is based on a dynamic vibration absorption effect caused by a dynamic damper having a structure in which an annular mass body is elastically connected to the outer periphery of the hub via a damper rubber in the circumferential direction in a predetermined vibration frequency band. The pulley reduces the torsional vibration of the crankshaft and absorbs the rotational torque (transmission torque fluctuation) of the drive torque input from the crankshaft to the hub by absorbing the circumferential deformation of the coupling rubber in the circumferential direction. It is transmitted to the main body.

  Further, in this type of rotational fluctuation absorbing pulley, if dust intervenes in the sliding portion of the bearing that rotatably supports the pulley body with respect to the hub side, the bearing may be worn out early, which is prevented. It is known to provide a seal lip as a means (see, for example, Patent Document 1 below).

JP 2007-170477 A

  The present invention has been made in view of the above points, and its technical problem is to prevent dust from entering the bearing sliding portion without relying on the seal lip in the rotational fluctuation absorbing pulley. There is.

The present invention employs the following means in order to solve the technical problems described above.
That is, the rotation fluctuation absorbing pulley according to the present invention is supported by a hub attached to a rotating shaft, a sensing plate attached to the hub and having a detected portion for detecting rotation, and a member on the hub side via a radial bearing. And a coupling rubber for mutually connecting the pulley body and the hub side member so as to be capable of relative displacement in the circumferential direction, and an outer peripheral portion of the sensing plate bends toward an outer peripheral side of the pulley body. (Claim 1).

  The rotation fluctuation absorbing pulley having the above configuration transmits the driving torque input from the rotating shaft to the hub to the pulley body while absorbing and smoothing the repetitive rotation fluctuation by the circumferential shear deformation action of the coupling rubber. The sensing plate is for measuring the rotation angle or the number of rotations of the rotating shaft, and rotates together with the hub. The sensing plate functions as a dust cover because the outer peripheral portion is bent toward the outer peripheral side of the pulley body, and dust enters the radial bearing that supports the pulley main body from the space on the outer peripheral side of the pulley main body. Effectively prevent

The present invention may further employ the following means in order to solve the above technical problem.
That is, in the rotation fluctuation absorbing pulley having the above-described configuration (claim 1), the hub-side member that supports the radial bearing is a sensing plate (claim 2).

  That is, in the above configuration, the sensing plate also has a function as a support means for the radial bearing.

  Furthermore, in the rotation fluctuation absorbing pulley having the above-described configuration (claim 1 or 2), the detected portion for rotation detection includes a plurality of protrusions formed in a circumferential direction on the outer peripheral portion of the sensing plate, and the sensing The plate is provided with a required number of air holes located on the inner peripheral side of the detected portion (claim 3).

  That is, in the above-described configuration, the detected portion formed of a large number of protrusions formed side by side in the circumferential direction and bent toward the outer peripheral side of the pulley main body is rotated from the inner peripheral side vent hole to the outer peripheral side of the pulley main body during rotation. Since the pumping function of sending out air is exerted, the air flow created thereby effectively works to prevent dust from entering from the outer space of the pulley body.

  According to the rotation fluctuation absorbing pulley according to the present invention, the outer peripheral portion of the sensing plate attached to measure the rotational angle or the rotational speed of the rotary shaft is bent toward the outer peripheral side of the pulley body, thereby generating dust. Since it functions as a cover, it is possible to effectively prevent the deterioration of the durability of the radial bearing due to the intrusion of dust from the outer peripheral side of the pulley body without depending on the seal lip.

1 is a cross-sectional view showing a first preferred embodiment of a rotational fluctuation absorbing pulley according to the present invention, cut along a plane passing through an axis O. FIG. It is sectional drawing which cuts and shows preferable 2nd embodiment of the rotation fluctuation absorption pulley which concerns on this invention by the plane which passes along the axial center O. FIG. FIG. 6 is a half sectional view showing a third preferred embodiment of a rotational fluctuation absorbing pulley according to the present invention by cutting along a plane passing through an axis O;

  Hereinafter, preferred embodiments of a rotation fluctuation absorbing pulley according to the present invention will be described with reference to the drawings. The “front side” used in the following description is the left side in the figure and the front side of the vehicle, and the “back side” is the right side in the figure and there is an unillustrated engine. That is the side.

  FIG. 1 shows a first preferred embodiment of a rotational fluctuation absorbing pulley according to the present invention. Reference numeral 1 denotes a hub attached to a shaft end of a crankshaft (not shown) of an automobile engine. . The hub 1 is manufactured by casting a metal material or the like, and has a boss portion 11 that is externally fixed to the crankshaft, and an annular step that extends from the front end of the boss portion 11 to the outer diameter side. It consists of the support cylinder part 13 extended from the part 12 and the cylindrical shape concentric with the boss | hub part 11 toward the front side from the outer-diameter end. The crankshaft corresponds to the rotating shaft described in claim 1.

  A sensing plate 2 is attached to the hub 1. The sensing plate 2 is made of a magnetic metal plate such as a steel plate, and includes a fitting cylinder portion 21 press-fitted to the outer peripheral surface of the support cylinder portion 13 of the hub 1 and a front surface from an end on the back side. The flange portion 22 that extends toward the outer diameter side while being inclined toward the outer side, the support cylinder portion 23 that extends in a cylindrical shape from the outer diameter end to the back surface side, and a disk-like shape developed from the rear end portion of the support cylinder portion 23. An outer diameter flange portion 24 is provided, and a large number of detected protrusions 25 are formed on the outer peripheral portion of the outer diameter flange portion 24 at predetermined intervals in the circumferential direction. A sensor (not shown) such as a magnetic type or a Hall effect type is disposed close to one place in the circumferential direction on the outer peripheral side of the sensing plate 2.

  A pulley body 4 is supported on the outer periphery of the support cylinder portion 23 of the sensing plate 2 via a radial bearing 3 so as to be concentric and relatively rotatable. The radial bearing 3 is formed into a cylindrical shape with a synthetic resin material having a low friction coefficient and excellent in wear resistance such as PTFE (polytetrafluoroethylene), and is held on the outer periphery of the support cylinder portion 23 of the sensing plate 2. The pulley body 4 is made of metal and has a belt winding portion 41 positioned on the outer peripheral side of the radial bearing 3 and a fitting cylinder portion 42 on the front side thereof. A poly V groove 41a around which a transmission belt (not shown) is wound is formed on the outer peripheral surface of the belt winding portion 41.

  The fitting cylinder part 42 of the pulley body 4 and the fitting cylinder part 21 of the sensing plate 2 which is a member on the hub 1 side are connected to each other via a coupling rubber 5 so as to be capable of relative displacement in the circumferential direction. The coupling rubber 5 includes an inner cylinder 52 press-fitted to the outer peripheral surface of the fitting cylinder portion 21 of the sensing plate 2 and an outer press-fitting fitting to the inner peripheral surface of the fitting cylinder portion 42 of the pulley body 4. A cylinder 53 and a coupling rubber body 51 made of a rubber elastic body integrally vulcanized and bonded (vulcanized and molded) between the inner cylinder 52 and the outer cylinder 53 are provided.

  The outer diameter flange portion 24 of the sensing plate 2 is on the back side of the back end portion 41b of the belt winding portion 41 of the pulley body 4, and is close to the back end portion 41b in the axial direction, and has a predetermined circumferential direction. Vent holes 24a are opened at intervals. The detected projection 25 located on the outer peripheral portion of the outer diameter flange portion 24 (the outer peripheral portion of the sensing plate 2) is inclined toward the outer peripheral side of the back end portion 41b of the belt winding portion 41 of the pulley body 4. Is bent. In addition, the inclination angle of the detected protrusion 25 is appropriately set so as not to interfere with the transmission belt wound around the belt winding portion 41 of the pulley body 4.

  The rotation fluctuation absorbing pulley according to the first embodiment having the above-described configuration is suitably provided, for example, on a crankshaft of a small-cylinder engine. That is, an engine with a reduced number of cylinders for improving fuel efficiency has a feature that the amplitude of torsional vibration due to resonance becomes extremely small because the crankshaft is short while the rotational fluctuation is large correspondingly. For this reason, the rotational fluctuation absorbing pulley of the first embodiment eliminates the need for a dynamic damper that reduces the torsional vibration of the crankshaft by the dynamic vibration absorption effect by resonating in the circumferential direction in a predetermined vibration frequency range. The weight reduction and price reduction have been realized.

  The driving torque of the crankshaft is transmitted from the hub 1 to the pulley body 4 via the fitting cylinder portion 21 of the sensing plate 2 and the coupling rubber 5, and is further wound around the belt winding portion 41 of the pulley body 4. It is transmitted to the rotating shaft of the auxiliary machine via a transmission belt (not shown). Here, as described above, a large rotational fluctuation occurs in the engine with a reduced number of cylinders. Such rotational fluctuation is caused by shearing deformation of the coupling rubber body 51 of the coupling rubber 5 in the circumferential direction by a low spring. Is effectively absorbed. Further, the radial bearing 3 slides with the relative displacement in the circumferential direction between the hub 1 side (sensing plate 2) and the pulley body 4 due to rotational fluctuation, thereby generating a frictional damping force.

  On the other hand, the sensing plate 2 rotates integrally with the hub 1, and a large number of detected protrusions 25 formed on the outer periphery thereof pass in front of a reading head of a sensor (not shown) arranged close to the outer periphery. Thus, a pulsed detection signal for measuring the crank angle or the rotational speed is output from this sensor.

  Further, the sensing plate 2 is bent by a shape in which an outer peripheral portion on which a large number of detected protrusions 25 are formed is inclined toward the outer peripheral side of the back end portion 41b in the belt winding portion 41 of the pulley body 4. In the stationary state, it functions as a dust cover that makes it difficult for dust to enter the radial bearing 3 side from the space on the outer peripheral side of the pulley body 4, and when rotating, a large number of inclined detection projections 25 rotate, thereby sensing plate 2. The air is sent out from the vent hole 24a formed in the outer diameter flange portion 24 to the outer peripheral side through the gap between the belt winding portion 41 of the pulley body 4 and the outer diameter flange portion 24 of the sensing plate 2. Since the pumping function is provided, the air flow created thereby effectively works to prevent dust from entering. For this reason, the durability of the radial bearing 3 can be improved.

  The sensing plate 2 has a function of measuring the crank angle or the number of revolutions, as well as a function of supporting the radial bearing 3 and a function of preventing dust from entering, so that the support of the radial bearing 3 is supported. The cost can be reduced as compared with the case where the means and the dust intrusion prevention means are provided separately.

  Next, FIG. 2 shows a second preferred embodiment of the rotational fluctuation absorbing pulley according to the present invention. The difference from the first embodiment described above is the outer periphery of the support cylinder portion 13 of the hub 1. A metal sleeve 61 is elastically and concentrically connected via a damper rubber 6 made of a rubber elastic body, and the fitting cylinder portion 21 of the sensing plate 2 is press-fitted to the outer peripheral surface of the sleeve 61. It is in. The damper rubber 6 is integrally vulcanized and bonded (vulcanized molding) between the support cylinder 13 of the hub 1 and the sleeve 61.

  In the second embodiment, the sleeve 61 and the sensing plate 2 and the inner cylinder 52 of the coupling rubber 5 which are integrally fitted to the sleeve 61 function as a mass body of a dynamic damper using the damper rubber 6 as a spring. The torsional direction resonance frequency of the dynamic damper is tuned so as to coincide with a predetermined frequency range where the torsion angle of the crankshaft is maximum, that is, the torsional direction resonance frequency region of the crankshaft.

  Accordingly, the rotational fluctuation absorbing pulley of the second embodiment is a dynamic damper in addition to the rotational fluctuation absorbing function by the circumferential shear deformation operation of the coupling rubber body 51 in the coupling rubber 5 and the frictional damping force of the radial bearing 3. This has the function of reducing torsional vibration due to crankshaft resonance by the dynamic vibration absorption effect.

  In addition to the function as a means for measuring the crank angle or the rotational speed, the sensing plate 2 has a function of supporting the radial bearing 3 and a function of preventing dust from entering, as in the first embodiment. And the outer peripheral portion on which the detected protrusion 25 is formed is bent into a shape inclined toward the outer peripheral side of the back end portion 41b of the belt winding portion 41 of the pulley main body 4, so that the pulley main body 4 is stationary when stationary. Functions as a dust cover that makes it difficult for dust to enter the radial bearing 3 side from the outer peripheral space of the outer periphery of the sensor plate. From the established air vent 24a, air flows between the belt winding portion 41 of the pulley body 4 and the outer diameter flange portion 24 of the sensing plate 2. It provides the pumping function to feed toward its outer peripheral side through the gap.

  Next, FIG. 3 shows a preferred third embodiment of the rotational fluctuation absorbing pulley according to the present invention. The difference from the first embodiment described above is a dynamic damper comprising a damper rubber 6 and a mass body 7. The coupling rubber body 51 of the coupling rubber 5 has a cylindrical shape, and the belt winding portion 41 of the pulley body 4 is disposed on the metal holding ring 71 that is a part of the mass body 7 via the radial bearing 3. It is in the point supported.

  Specifically, the dynamic damper includes a metal sleeve 62 press-fitted to the outer peripheral surface of the fitting cylinder portion 21 of the sensing plate 2, a holding ring 71 disposed on the outer peripheral side, and a front surface of the holding ring 71. A metal retainer 72 press-fitted to the outer peripheral surface of the side, and a damper rubber 6 integrally vulcanized and molded with a rubber elastic body between the sleeve 62 and the holding ring 71, and its twist direction The resonance frequency is tuned so as to coincide with a predetermined frequency range where the torsion angle of the crankshaft is maximum, that is, a torsional direction resonance frequency range of the crankshaft.

  The sensing plate 2 has a fitting cylinder portion 21 that is press-fitted into the outer peripheral surface of the hub 1 and a flange portion 22 that develops in a disk shape from the end on the back side thereof. 25 is formed at a predetermined interval in the circumferential direction, and is bent into a shape inclined toward the outer peripheral side of the back end portion 41 b of the belt winding portion 41 of the pulley body 4.

  The holding ring 71 includes an inner peripheral cylindrical portion 711 integrally joined to the outer periphery of the damper rubber 6 by vulcanization adhesion, a disk portion 712 that expands from the end on the back side to the outer peripheral side, and an outer periphery of the disk portion 712. A double cylindrical hollow shape consisting of a support cylindrical portion 713 extending from the front to the front side, that is, a shape cut along a plane passing through the axis O forms a substantially U-shape. The disk portion 712 of the holding ring 71 is adjacent to the front side of the flange portion 22 of the sensing plate 2.

  Thrust strips 63 and 64 made of a rubber elastic body continuous from the damper rubber 6 and continuously in the circumferential direction are integrally vulcanized and bonded to the outer surface of the disk portion 712 of the retaining ring 71, and the tip thereof is the sensing plate 2. The flange portion 22 is in close contact with the inner surface of the flange portion 22 so as to be slidable at an appropriate surface pressure. A radial lip 65 made of a rubber elastic body continuous from the thrust strips 63, 64 is integrally vulcanized and bonded to the outer peripheral portion of the disk portion 712 of the retaining ring 71, and the tip thereof is vulcanized. The outer periphery (back side) of the radial bearing 3 is in close contact with the inner peripheral surface of the belt winding portion 41 of the pulley body 4 so as to be slidable.

  The pulley body 4 includes an inward flange 43 that extends from the front end of the belt winding portion 41 toward the inner diameter side. The belt winding portion 41 is disposed on the outer periphery of the support cylinder portion 713 of the holding ring 71 on the radial bearing 3. Is supported through.

  The coupling rubber 5 includes a metal coupling flange member 54 that is press-fitted to the outer peripheral surface of the inner peripheral cylindrical portion 711 of the retaining ring 71 and is press-fitted to the outer peripheral surface of the retainer 72, and an inward flange 43 in the pulley body 4. The cylindrical coupling rubber body 51 is integrally vulcanized and molded between the two. That is, the coupling rubber 5 connects the pulley body 4 and the holding ring 71 that is a member on the hub 1 side as viewed from the pulley body 4 to each other so as to be capable of relative displacement in the circumferential direction.

  A thrust bearing 8 is slidably interposed between the axially opposed surfaces of the retainer 72 and the coupling flange member 54. The thrust bearing 8 is formed of a synthetic resin material having a low friction coefficient and excellent wear resistance such as PTFE.

  The rotation fluctuation absorbing pulley according to the third embodiment having the above configuration is also rotated by the circumferential shear deformation operation of the coupling rubber main body 51 in the coupling rubber 5 and the frictional damping force of the radial bearing 3 and the thrust bearing 8. In addition to the fluctuation absorbing function, it has a function of reducing torsional vibration due to crankshaft resonance by the dynamic damping effect of the dynamic damper.

  The sensing plate 2 functions not only as a means for measuring the crank angle or the number of revolutions but also as a dust intrusion prevention function, and has a support ring 71 for the radial bearing 3 (pulley body 4). It is carried by. That is, the sensing plate 2 is bent in a shape in which the outer peripheral portion on which the detected protrusion 25 is formed is inclined toward the outer peripheral side of the back end portion 41b of the belt winding portion 41 of the pulley body 4, thereby It functions as a dust cover that makes it difficult for dust to enter the radial bearing 3 side from the outer peripheral space of the pulley body 4, and when rotating, the dust intrusion is achieved by the pumping function by rotating a large number of inclined detection protrusions 25. Can be effectively prevented.

DESCRIPTION OF SYMBOLS 1 Hub 2 Sensing plate 23 Support cylinder part 24a Vent hole 25 Detected protrusion 3 Radial bearing 4 Pulley body 5 Coupling rubber

Claims (3)

  A hub attached to the rotation shaft, a sensing plate attached to the hub and having a detected portion for detecting rotation, a pulley body supported by a member on the hub side via a radial bearing, the pulley body and the hub A rotation fluctuation absorbing pulley comprising a coupling rubber for connecting the side members to each other so as to be relatively displaceable in the circumferential direction, and an outer peripheral portion of the sensing plate bent toward an outer peripheral side of the pulley body .   The rotation fluctuation absorbing pulley according to claim 1, wherein the hub-side member that supports the radial bearing is a sensing plate.   The detected portion for rotation detection is composed of a number of protrusions formed in a circumferential direction on the outer peripheral portion of the sensing plate, and is positioned on the inner peripheral side of the detected portion on the sensing plate. The rotation fluctuation absorbing pulley according to claim 1 or 2, wherein a ventilation hole is formed.

Images