JP2005233302A - Power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the absorbing effect for the variation in rotational angular velocity of a rotational power fed at the time of transmitting the power. <P>SOLUTION: The power transmission device is structured so that projections 2a and 3a protruding toward each other are formed on a pulley 2 and a rotor shaft 3 and a resilient piece 8 to absorb a rotational variation of the pulley 2 is accommodated in the space 7 between the projections 2a and 3a. When the rotational power is transmitted from the pulley 2 to the rotor shaft 3, a friction member 9 is pressed to the pulley 2 by a pressing member 10. The pulley 2 itself is going to vibrate with a variation in angular velocity of the rotational power fed to the pulley 2, but the vibration of the pulley 2 is damped by allowing the friction member 9 to give an appropriate friction force to the pulley 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a power transmission device such as a pulley unit. This type of power transmission device can be installed in, for example, an engine crankshaft or auxiliary machinery driven from the crankshaft via a transmission belt. Examples of the auxiliary machines include an automobile alternator, an air conditioner compressor, a water pump, and a cooling fan.

  When transmitting a rotational driving force of the engine to the crankshaft accessory via the transmission belt from the (drive side) machine (driven side), due to the slight change of the rotational angular velocity at the crank shaft, happening slipping transmission belt different Sound tends to be generated. This will be described an alternator, which is one of the auxiliaries for example. If the engine as a drive source, the operation process of the engine crankshaft during its rotation, there is always a slight change of the rotational angular velocity. On the other hand, the alternator rotor, the inertia torque is afflicted with a large rotational inertia (moment of inertia). Therefore, the alternator rotor, is driven by the crankshaft with a slight change of the rotational angular velocity, momentarily, it occurs power circulation via a transmission belt between the crankshaft side and the rotor side, tight side of the driving belt and the loose side phenomenon to reverse occurs. This rotational driving force sent from the crankshaft to the rotor, at the time of reduction of the fine variation of the rotational angular velocity is returned to the crankshaft, when the increase of the fine variation of the rotational angular velocity, that the rotor is rotated accelerated by the crankshaft Become. As a result, the inertial torque of the rotor is applied to the transmission belt, and the transmission belt tends to slip and generate abnormal noise or decrease durability.

  Therefore, a pulley transmission belt is wound (outer ring member) provided with a rotor shaft (inner ring member) which is integrally rotatably coupled to the alternator rotor, the inner circumferential surface of the pulley and the outer peripheral surface of the rotor shaft in several locations circumferentially disposed projections respectively, when both convex portion of the elastic body such as rubber or a spring disposed in the space facing in the circumferential direction, there is a slight change in the angular velocity of the pulley in the There is one that absorbs minute fluctuations in rotational angular velocity and suppresses rotation fluctuations of the rotor shaft by expanding and contracting an elastic body (see, for example, Patent Document 1).

In the power transmission device as described above, the pulley is vibrated with the rotation fluctuation which is input to the pulley, there is a risk of resonance elastic body by approaching the natural frequency of the elastic body this vibration is expansion and contraction. When such resonance occurs, expansion and contraction of the elastic body becomes unstable, the effect of absorbing the minute variation of the rotational angular velocity may decrease.
JP 2002-303333 A

  The present invention includes an outer ring member of the pulley or the like, in the power transmission device of a pulley unit or the like provided with an inner ring of the rotor shaft such as to stabilize the stretching operation of the elastic body, to enhance the absorbing effect of the rotational fluctuation Is an issue.

  A power transmission device according to the present invention is a power transmission device that includes an outer ring body and an inner ring body that is arranged on the inner peripheral side of the outer ring body and transmits rotational power to and from the outer ring body. The convex portion provided on the inner peripheral surface of the outer ring body and the convex portion provided on the outer peripheral surface of the inner ring body so as to face the convex portion in a circumferential direction through a space. And an elastic body housed in a circumferentially opposed space between both convex portions, a friction member that is in contact with one of the two rings, and a pressing member that presses the friction member against the one ring. It is characterized by this.

  Here, the outer ring member and the input side of the rotational power, a case where the inner ring member to the output side of the rotational power, and a case of the reverse. The inner ring body may be hollow or solid. Elastic body, as long as it expands and contracts elastically in the circumferential direction, the pressing member is not limited as long as it expands and contracts elastically in the axial direction, both, for example a coil spring or a disc spring or undulating plate other such as a spring, it may be rubber or synthetic resin having a predetermined elasticity. As a material of the friction member, for example, in addition to a sintered metal material, a phenol resin, or the like, a material commonly used for a well-known clutch facing or an appropriate resin material can be appropriately selected and used, and is particularly limited. It is not a thing.

  According to the present invention, for example, in usage from the outer ring member for transmitting rotational power to the inner ring member, when the rotational power input to the outer ring body such that slight change, when an increase in the rotational angular velocity of the outer ring body The convex portion on the outer ring side approaches the convex portion on the inner ring side located on the front end side in the rotation direction, and the elastic body between these two convex portions is elastically compressed and deformed, so that the outer ring is changed to the inner ring. Delay transmission of rotational power. On the other hand, approaches the projecting portion of the outer ring side of the inertia force of the inner ring body at the time of decrease in angular velocity of the outer ring member is convex portion of the inner ring side located in the rotational direction leading end side, an elastic body between these protrusions by elastically compressed and deformed, the transmission of rotational power from the outer annulus to the inner annulus is blocked. Absorb slight change of rotational power of the outer ring member by expansion and contraction of such an elastic body, suppresses the rotational fluctuation of the inner ring member. During such operation, the outer ring tries to vibrate due to minute fluctuations in the rotational power input to the outer ring, but since the friction member gives rotational resistance to the outer ring, vibration is to be damped, an elastic body is prevented from resonating. Accordingly, since the expansion and contraction of the elastic body becomes to be stably performed, it is possible to enhance the absorbing effect of the rotational variation of the outer ring member by the elastic body as described above.

  Preferably, two or more of the two convex portions are provided at equal circumferential intervals on the outer ring body and the inner ring body, and the friction member is arranged in the radial direction on the convex portion on the inner ring body side and on the outer ring body side. is provided in a state sandwiched between axially facing surfaces of the flange portion provided integrally inwardly, the pressing member is in a lateral hole provided along the axial direction on the convex portion of the inner ring side It is accommodated so as to resiliently urging the friction member to the outer ring side.

  Preferably, the outer ring member, that from the crankshaft of the engine and pulley transmission belt is wound for power transmission, the structure of a pulley unit comprising a rotor shaft connected to the inner ring member to the alternator rotor Can do.

  In the present invention, the outer ring of the pulley or the like, in the power transmission device of a pulley unit or the like provided with an inner ring of the rotor shaft or the like, when power transmission between the ring body, to stabilize the expansion and contraction of the elastic body Te, can be absorbed efficiently slight change of the rotational power input angular velocity.

  Hereinafter will be described the preferred embodiments of the present invention shown in FIG. 1 is a pulley unit, and is a cross-sectional view taken along line (1)-(1) in FIG. 2. FIG. 2 is a diagram in which a substantially axial center of the pulley unit in FIG. is a perspective view showing in isolation the rotor shaft, the friction member and the pressing member. The present invention will be described as applied to a pulley unit as a power transmission device.

  Pulley unit 1 of the embodiment shown in these figures, the pulley 2 as an outer ring member, disposed on the inner peripheral side of the pulley 2 as an inner ring member which transmits rotational power between the pulley 2 comprising the rotor shaft 3, and a rolling bearing 4, 5 disposed at both axial ends of the rotor shaft 3 between the pulley 2 and the rotor shaft 3. Rolling bearings 4 and 5, consists of deep groove ball bearing lubricant sealed type.

  First, the configuration of the pulley 2 and the rotor shaft 3.

  Protrusions 2a projecting inward in the radial direction are provided at several places in the middle of the inner peripheral surface of the pulley 2 in the axial direction, preferably at two places facing each other at 180 degrees. On the outer peripheral surface of the pulley 2, a wavy groove for winding the transmission belt 6 is formed. The inner periphery of the other axial end of the pulley 2 (corresponding to the free end of the rotor shaft 3) is provided radially inwardly of the flange portion 2b.

  The rotor shaft 3, for example the crankshaft axis of rotation and an engine auxiliary machine comprising a vehicle is integrally rotatably coupled. Convex portions 3a projecting outward in the radial direction are respectively provided at several circumferential positions in the middle of the outer circumferential surface of the rotor shaft 3, preferably at two positions facing each other at 180 degrees. Each protrusion 3a of the rotor shaft 3, the lateral hole 3b along the axial direction are respectively provided. The other axial end surface of the projection 3a of the rotor shaft 3 (the surface of the free end of the rotor shaft 3), the recess 3c is provided.

  A fan-shaped space 7 is formed between each of the convex portions 2a on the pulley 2 side and each of the convex portions 3a on the rotor shaft 3 side in the circumferential direction (between four opposing locations in the figure). and has an elastic body 8 made of a coil spring in each of the fan-shaped space 7 is accommodated in a compressed state.

  In the present embodiment, with respect to the pulley 2 and the rotor shaft 3 of the above configuration, and a friction member 9 and the pressing member 10 follows.

  Friction member 9 by being pressed by the pressing member 10 against the flange portion 2b of the pulley 2, is intended to impart appropriate rotational friction force to the pulley 2. Friction member 9, a plate shape which is formed in a substantially fan shape, protrusions 9a are provided to each widthwise end of the curving direction center. The pressing member 10 is made of, for example, a coil spring, is accommodated in a compressed state lateral hole 3b of the convex portion 3a of the rotor shaft 3. The protrusions 9a of the friction member 9 are engaged with the concave portions 3c of the convex portion 3a of the rotor shaft 3, and the friction member 9 is positioned on the convex portion 3a of the rotor shaft 3 in the circumferential direction by this engagement. Has been. The pressing member 10 is in contact with the area between the projections 9a of the friction member 9. Friction member 9 and the pressing member 10 is provided in the same number as the protruding portions 2a of the respective convex portions 3a or pulleys 2 of the rotor shaft 3. Further, the rotational frictional force applied to the pulley 2, or selects the material of the friction member 9 appropriately, or by appropriately setting to the elastic biasing force of the pressing member 10, is adjustable.

  Referring to FIGS. 4-6, the operation of the pulley unit 1. Figure 4 is a sectional view used for explaining the operation when the rotational angular velocity increases of the pulley unit 1, FIG. 5 is a sectional view used for explaining the operation when the rotational angular velocity reduction in the pulley unit 1, FIG. 6, the pulley 2 and the rotor shaft 3 It is a graph which shows the rotation waveform of.

  Here, a case where the pulley unit 1 is used as, for example, an alternator of an automobile will be described as an example. The alternator is an AC generator that is driven by a transmission belt from an engine of an automobile vehicle, and is composed of a rotor, a stator, a regulator, a rectifier, and the like (not shown). The rotor shaft 3 is attached to the rotor of the alternator, and the pulley 2 is rotationally driven by a transmission belt 6 that is rotationally driven by the crankshaft of the engine. In this example, the pulley 2 is the rotational power input side, and the rotor shaft 3 is the rotational power output side. Generally, since the rotational speed of the crankshaft fluctuates slightly at a predetermined cycle, the rotational angular velocity of the pulley 2 that is rotationally driven from the crankshaft through the transmission belt 6 fluctuates slightly in accordance with the predetermined cycle. On the other hand, in this embodiment, the minute fluctuations in the rotational angular velocity of the pulley 2 can be efficiently absorbed so that the fluctuations in the rotation of the rotor shaft 3 can be suppressed. This will be described below.

[1] in the direction of rotation indicated if Figure 4 the rotational angular velocity of the pulley 2 increases, the rotational angular velocity of the pulley 2 increases, the rotation direction front end face 2d of the convex portion 2a of the pulley 2 of the convex portion 3a of the rotor shaft 3 approaching the rotation direction rear end face 3e, resiliently compressive deformation of the elastic body 8 in the circumferential direction between the rotational direction rear end surface 3e of the rotation direction front end face 2d and the convex portion 3a of the convex portion 2a. Thereby, the rotational power is transmitted from the pulley 2 to the rotor shaft 3 with a delay. At this time, the elastic body 6 between the rotation direction rear end surface 2e of the projection 2a and the rotation direction front end surface 3d of the projection 3a is elastically stretched in the circumferential direction. Thereby, the increase in the rotational angular velocity of the pulley 2 is absorbed.

[2] in the direction of rotation indicated if Figure 5 the rotational angular velocity of the pulley 2 decreases, the rotational angular velocity of the pulley 2 decreases, the rotational inertia force acting on the rotor shaft 3, the rotor shaft 3 is advanced than the pulley 2 become. Thus, the rotation direction front end face 3d of the convex portion 3a of the rotor shaft 3 is approaching the rotation direction rear end surface 2e of the convex portion 2a of the pulley 2, after the rotation direction of the rotation direction front end face 3d and the projecting portion 2a of the convex portion 3a The elastic body 6 between the end face 2e is elastically compressed and deformed in the circumferential direction. As a result, transmission of rotational power from the pulley 2 to the rotor shaft 3 is interrupted. At this time, the elastic body 6 between the rotational direction front end surface 2d of the convex portion 2a and the rotational direction rear end surface 3e of the convex portion 3a is elastically stretched. As a result, the decrease in the rotational angular velocity of the pulley 2 is absorbed.

  By the expansion / contraction operation of the elastic body 8, as shown in FIG. 6, it is possible to absorb minute fluctuations in the rotational power of the pulley 2 and suppress rotation fluctuations of the rotor shaft 3. As a result, tight side of the driving belt 6 wound around the pulleys 2 and (downstream side in the rotational direction), since it becomes possible to reduce the tension variation amount of the slack side (upstream side in the rotational direction), the transmission belt 6 is borne to reduce the torque and prevent the occurrence of abnormal noise due to slippage of the transmission belt 6, it becomes possible to improve the durability of the transmission belt 6.

  Moreover, during this operation, although the pulley 2 and the rotor shaft 3 by slight change of rotational power input to the pulley 2 is about to vibration, since the applied rotational resistance to the pulley 2 with the friction member 9, supposed to vibration of the pulley 2 is attenuated, the elastic body 8 is prevented from resonating. Thus, expansion and contraction of the elastic body 8 is adapted to be stably performed, it is possible to enhance the absorbing effect of the rotational variation of the pulley 2 by the elastic body 8.

  Further, a configuration for imparting a frictional force to pulley 2 is also friction member 9 and the pressing member 10 and because a simple structure with, the cost increase can be suppressed.

  Hereinafter, other embodiments and application examples of the present invention will be described.

  (1) For example, the rotor shaft 3 can be the rotational power input side and the pulley 2 can be the rotational power output side. As an example, a configuration in which the pulley unit 1 is attached to the crankshaft is conceivable. The operation in this case is basically the same as in the above embodiment.

  (2) Although not shown, the number of the projections 2a and the convex portion 3a of the rotor shaft 3 of the pulley 2 may be a 2 or more, respectively. In that case, the convex portions 2a, the number of the elastic member 8 and the friction member 9 and the pressing member also has to be increased use in accordance with the number of 3a.

  (3) friction members 9 may be a single circular plate.

In pulley unit according to the preferred embodiment of the present invention, in FIG. 2 (1) - (1) line arrow view of the cross-section Figure in which the substantially axial center section in the radial direction of the pulley unit 1 Rotor shaft of Figure 1, a perspective view illustrating in isolation the friction member and the pressing member Sectional view used for explaining the operation at the time of increase in angular velocity of the pulley unit 1 Sectional view used for explaining the operation when the rotational angular velocity reduction in the pulley unit 1 Graph showing rotation waveform of pulley and rotor shaft

Explanation of symbols

  1 ... pulley unit, 2 ... pulley, the convex portion of 2a ... pulley, 3 ... rotor shaft, 3a ... convex portion of the rotor shaft, 4,5 ... rolling bearing 7 ... space, 8 ... elastic body, 9 ... friction member, 10: Pressing member.

Claims (3)

An outer ring member, a power transmission device including an inner ring member which transmits rotational power between the disposed on the inner peripheral side of the outer ring body the outer ring member,
A protrusion provided on an inner peripheral surface of the outer ring member,
The outer peripheral surface of the inner ring member, while facing with the air in the circumferential direction relative to the convex portion, and a protrusion provided,
An elastic body housed in a circumferentially facing space between both convex portions;
A friction member which is in contact with one ring member of both annulus,
Power transmission device characterized by comprising a pressing member for pressing the friction member on one annulus. The both projections, respectively to the outer ring member and the inner ring member are provided two or more circumferentially equally spaced, the friction member, the convex portion and radially inwardly to the outer ring side of the inner ring side It is provided in a state of being sandwiched between axially opposed surfaces with the flange provided integrally,
The pressing member is accommodated to resiliently urging the outer ring side of the friction member in a lateral hole provided along the axial direction on the convex portion of the inner ring side, it in claim 1, wherein the power transmission device according.   The outer ring member, and the engine crank shaft and pulley transmission belt is wound for power transmission, the structure of a pulley unit comprising a rotor shaft connected to the inner ring member to the alternator rotor, the said the power transmission device according to claim 1 or 2,.

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