JP2005249037A - Power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission device, attaining improvement of the generation of abnormal sound of a transmission belt and durability, and having excellent reliability over a long period of time in a pulley unit, for example. <P>SOLUTION: In this pulley unit 1, a pulley 2 which a belt 8 is wrapped round and a rotor shaft 3 are connected to each other through a power transmission medium member 4, the inner peripheral surface 23 of the pulley 2 and the outer peripheral surface 25 of the rotor shaft 3 are respectively provided with projecting parts 15, 17, 16, 18 formed on the surface 23 and the surface 25 alternately in the circumferential direction. Springs 19, 20 and dampers 21, 22 are stored to function in a pair in the circumferential direction in the storing spaces A1, A2, B1, B2 between the projecting parts 15, 17, 16, 18. <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, since the rotor of the alternator has a large rotational inertia (moment of inertia), inertia torque is applied to the rotor. For this reason, when the alternator rotor is driven by a crankshaft with minute fluctuations in the rotational angular velocity, the transmission belt loosens and tension changes, and tension fluctuations occur. On the transmission belt, the rotor inertia torque As a result, slippage occurs in the transmission belt and abnormal noise is generated or durability tends to be lowered.

In addition, as a conventional technique, convex portions are respectively provided at several circumferential positions on the inner peripheral surface of the pulley around which the transmission belt is wound and the outer peripheral surface of the rotor shaft connected to the rotor of the alternator so as to be integrally rotatable. There has been proposed a power transmission device in which an elastic body such as rubber or a spring is disposed in a space where both convex portions oppose each other in the circumferential direction (see, for example, Patent Document 1).
JP 2002-303333 A

  The present invention provides a power transmission device that is excellent in reliability over a long period of time by generating abnormal noise and improving durability of the belt.

  A power transmission device according to the present invention is a power transmission device that transmits rotational power between both inner and outer rings arranged concentrically, and a radially inward convex portion on an inner peripheral surface of the outer ring, A plurality of storage spaces are formed between the circumferential directions of the respective convex portions by providing radially outward convex portions on the outer peripheral surface of the inner ring body so as to be alternately arranged in the circumferential direction. A spring is accommodated so as to receive a rotational torque based on a rotational fluctuation of the body, and a damper is accommodated in at least one so as to attenuate the vibration of the spring.

  In this case, the storage space may be arranged at a position facing the radial direction, and the spring and the damper may be housed in the storage space arranged to face each other.

  When the power transmission device of the present invention is applied to, for example, a pulley unit, when a pulley as an outer ring is driven from the crankshaft side of the engine via a belt, for example, an inner ring is formed via the spring and the damper. The rotor shaft rotates.

  In a situation where the belt tension fluctuates and the rotor shaft cannot follow the tension fluctuation due to its inertia torque, the belt tension fluctuation is received by the compression and extension of the spring. There is no need to slip. This suppresses or eliminates the occurrence of abnormal noise on the belt and further improves durability.

  On the other hand, the spring vibrates as compression and extension due to the above-described tension fluctuation, and this vibration is attenuated by the damper. As a result, since it is not necessary to receive the tension fluctuation only with the damper, the damper is able to reduce its aged deterioration.

  From the above, in the present invention, the belt tension fluctuation is absorbed by the spring, and the noise of the belt can be generated and the durability can be improved. On the other hand, the vibration of the spring is damped by the damper. It is possible to provide a highly reliable power transmission device that enables smooth power transmission over a wide range.

  In the power transmission device disclosed in Patent Document 1, since only either a damper or a spring is stored in each storage space, for example, if only the damper is stored, fluctuations in belt tension can be suppressed. However, the damper is likely to deteriorate over time due to the load due to the tension fluctuation, and if only the spring is housed, it is difficult to suppress the vibration fluctuation of the spring even if the tension fluctuation of the belt can be suppressed, and the power is transmitted smoothly. There is a problem that it becomes difficult. On the other hand, according to the present invention, since the members having different elastic characteristics such as the damper and the spring are used, the above-described operational effects can be obtained.

  According to the present invention, in a power transmission device that transmits the rotational driving force of an engine to an auxiliary machine such as an alternator from a crankshaft via a transmission belt, for example, in a pulley unit, generation of abnormal noise in the transmission belt and improvement in durability. Therefore, it is possible to provide a power transmission device with excellent reliability over a long period of time.

  The best mode of the present invention will be described below with reference to the drawings. In this embodiment, the power transmission device is applied to a pulley unit used for a vehicle auxiliary machine. FIG. 1 is a side sectional view showing the overall configuration of the pulley unit, and FIGS. 2 and 3 are front sectional views.

  The pulley unit 1 shown in these drawings includes a pulley 2 as an outer ring and a rotor shaft as an inner ring that is arranged on the inner peripheral side of the pulley 2 and transmits rotational power to and from the pulley 2. 3, a mediating member 4 that is arranged in the middle of the pulley 2 and the rotor shaft 3 in the axial direction and mediates power transmission from the pulley 2 to the rotor shaft 3, and the shaft of the pulley 2 and the rotor shaft 3. Rolling bearings 5 and 6 are provided between both ends in the direction.

  The rolling bearings 5 and 6 are interposed one by one on both sides in the axial direction in the annular space between the pulley 2 and the rotor shaft 3, respectively, an outer ring 7, an inner ring 8, a plurality of balls 9, respectively. This is a general deep groove ball bearing composed of a crown-shaped cage 10 to be held and a seal ring 11.

  Convex portions 15 and 16 (drive-side first and second convex portions) projecting inward in the radial direction at the circumferential places in the axial direction of the inner peripheral surface of the pulley 2, preferably at two locations facing each other at 180 ° ) Is provided. On the outer peripheral surface of the pulley 2, a wavy groove (belt winding portion) for winding the transmission belt 6 is formed. A radially inward flange 2a is provided on the other axial end of the inner periphery of the pulley 2 (corresponding to the free end of the rotor shaft 3).

  The inner peripheral surfaces 15c and 16c of the drive side first and second convex portions 15 and 16 can be slidably brought into contact with the outer peripheral surface 25 of the rotor shaft 3, and the respective circumferences of the drive side first and second convex portions 15 and 16 are provided. The direction side surfaces 15a, 15b, 16a, 16b are formed along the radial direction. Between the drive side 1st convex part 15 and the drive side 2nd convex part 16 of the internal peripheral surface 23 of the pulley 2, it forms in the cylindrical surface which has a predetermined curvature.

  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 17 and 18 (driven first and second convex portions on the driven side) projecting radially outward at two circumferential positions in the middle of the outer peripheral surface of the rotor shaft 3, preferably at two positions facing each other at 180 ° ) Are provided.

  The driven side first and second convex portions 17 and 18 are formed to project radially outward on the outer peripheral surface of the rotor shaft 3 so as to be disposed between the driving side first and second convex portions 15 and 16. The first and second convex portions 17 and 18 and the drive side first and second convex portions 15 and 16 are arranged alternately in the circumferential direction.

  One opposing side surface 17a, 18a facing the circumferential direction of the driven side first and second convex portions 17, 18 is formed along the radial direction, and the other opposing side surface 17b, 18b facing the circumferential direction is It is formed in the protruding curved surface which curves and inclines toward one opposing side surface. A space between the driven first and second convex portions 17 and 18 of the outer peripheral surface 25 of the rotor shaft 3 is formed as a cylindrical surface having a predetermined curvature.

  In the opposing annular space between the pulley 2 and the rotor shaft 3, between the respective opposed portions 17, 18 on the rotor shaft 3 side and the respective convex portions 15, 16 on the pulley 2 side in the circumferential direction (four locations in the figure) Storage spaces A1, A2, B1, and B2 are formed between the two facing each other.

  The power transmission mediating member 4 includes elliptical and coiled first and second springs 19 and 20 that are stored in a compressed state in the storage spaces A1 and A2, and a first rectangular section that is stored in the storage spaces B1 and B2. , Second dampers 21 and 22. The first and second springs 19 and 20 are preferably made of metal, but rubber, resin, or the like may be used as the spring material. In short, the deflection changes due to an increase or decrease in load, and energy can be absorbed and accumulated. What is necessary is just to have the property as a spring. The first and second dampers 21 and 22 are preferably made of rubber, particularly hard rubber. However, the first and second dampers 21 and 22 are not limited to this. As long as a damper (vibration suppression or vibration suppression such as vibration control) function can be exhibited. Even if it is a resin type | system | group, if the property like rubber | gum can be provided, it can also comprise with the said resin type | system | group.

  The first and second springs 19 and 20 are located between the circumferential side surfaces 15a and 15b of the driving side first convex portion 15 and one opposing side surfaces 17a and 18a of the driven side first and second convex portions 17 and 18. Are arranged in the storage spaces A1 and A2, respectively, and the circumferential side surfaces 15a and 15b and the opposite side surfaces 17a and 18a are used as spring seats.

  Each of the first and second dampers 21 and 22 has curved outer peripheral surfaces 21b and 22b along the inner peripheral surface 23 of the pulley 2 and curved inner peripheral surfaces 21c and 22c along the outer peripheral surface 25 of the rotor shaft 3, It is formed in an arc belt-shaped circumferential cross section having a predetermined axial width, and is disposed in storage spaces B1, B2 between the driving side second convex portion 16 and the driven side first and second convex portions 17, 18, respectively. Yes.

  The base end side surfaces 21a and 22a of the first and second dampers 21 and 22 are formed on flat surfaces that can come into contact with the circumferential side surfaces 16a and 16b of the drive side second convex portion 16, and the first and second dampers are formed. A recess 32 having a short protrusion 30 on the radially inner side and a long protrusion 31 on the radially outer side on the tip end side of 21, 22, and retreating in the circumferential direction between the protrusions 30, 31 in the radial direction. The short protrusion 30 is disposed so as to be able to contact the projecting curved surfaces 17a, 18a of the driven side first and second convex portions 17, 18 by pressure contact or the like.

  In the pulley unit 1, when the belt 8 rotates as the crankshaft (not shown) rotates, the pulley 2 is driven to rotate by the rotation. Then, the rotor shaft 3 is rotated by the power transmitted from the pulley 2 via the power transmission mediating member 4. In this case, a process of rotating the pulley 2 and transmitting the rotational power to the rotor shaft 3 via the power transmission medium member 4 will be described. As shown by the phantom line in FIG. With the clockwise rotation, the driving side first convex portion 15 of the pulley 2 approaches the driven side first convex portion 17, and the circumferential side surface 15 a of the driving side first convex portion 15 makes the first spring 19 elastic. The first springs 19 are pressed against each other and compressed between the circumferential side surface 15 a and the opposite side surface 17 a of the driven side first convex portion 17, and the driving side first convex portion 15 becomes the driven side first convex portion 17. By approaching the circumferential direction, that is, when the driving side first convex portion 15 is separated from the driven second convex portion 18 in the circumferential direction, the second spring 20 becomes free.

  Further, the driving-side second convex portion 16 of the pulley 2 approaches the driven-side second convex portion 18, and the circumferential side surface 16a of the driving-side second convex portion 16 presses the second damper 22 against its elasticity. This compresses and elastically deforms, and the driving side second convex portion 16 approaches the driven side second convex portion 18 in the circumferential direction. That is, the driving side second convex portion 16 extends from the driven side first convex portion 17 in the circumferential direction. The 1st damper 21 will be in a free state by leaving | separating. As described above, the first spring 19 is compressed and the opposed side surface 17a of the driven first convex portion 17 is pushed, so that the rotor shaft 3 is driven and rotated by the pulley 2.

  A case where the crankshaft rotates in a pulsating manner will be described. When the angular velocity of the pulley 2 increases and fluctuates due to the pulsating rotation of the crankshaft, the first spring 19 is compressed and transmitted to the rotor shaft 3 in the same manner as described above for the increased variation of the angular velocity. On the other hand, the first spring 19 expands due to the reaction of the compression and tries to generate a vibration that compresses by the reaction. At this time, the second damper 22 protrudes from the protruding curved surface of the second convex portion 18 on the driven side. The vibration is attenuated by frictional contact with 18b. Thereby, even if the first spring 19 is compressed, it is possible to suppress the fluctuation from being transmitted to the rotor shaft 3. As described above, even if the angular velocity of the pulley 2 is increased or fluctuated due to the pulsating rotation of the crankshaft, the tension variation is absorbed by the first spring 19 and the vibration of the first spring 19 is absorbed by the second damper. 22, the power from the pulley 2 is smoothly transmitted to the rotor shaft 3 even if the belt changes its tension. It is suppressed and durability is improved.

  In addition, since both protrusions 30 and 31 of the second damper 22 are disposed via a recess 32 that retreats in the circumferential direction, the short protrusion 30 that contacts the protruding curved surface 18b of the driven second protrusion 18 is particularly easily bent. By making the shape easy to elastically restore, the short protrusion 30 is elastically restored when the second damper 22 is in a free state, so that the damping of the first spring 19 can be effectively promoted.

  When the angular velocity of the pulley 2 decreases and fluctuates due to the pulsating rotation of the crankshaft, the second spring 20 can be suppressed from being compressed and transmitted to the pulley 2 with respect to the decrease variation of the angular velocity, while the second spring The first damper 21 frictionally abuts against the protruding curved surface 17b of the driven first convex portion 17 at that time. Damping vibration. Accordingly, even if the second spring 20 is compressed, it is possible to suppress the fluctuation from being transmitted to the pulley 2. As described above, even if the angular velocity of the pulley 2 decreases and fluctuates due to the pulsating rotation of the crankshaft, the tension fluctuation is absorbed by the second spring 20 and the vibration of the second spring 20 is absorbed by the first damper 21. Since the belt 8 is damped and the belt 8 does not slip on the pulley 2, the occurrence of abnormal noise is suppressed, and the durability is improved.

  Furthermore, since both the protrusions 30 and 31 of the first damper 21 are disposed via the recesses 32 that are retracted in the circumferential direction, the short protrusion 30 that contacts the protruding curved surface 18b is particularly easily bent and elastically restored. Thus, the unstable behavior of the pulley 2 can be effectively suppressed.

  By the way, even when the elastic body is made entirely of a damper without using a spring, it is possible to absorb an increase in the angular velocity of the pulley 2, but there is a problem that the damper is likely to deteriorate over time. Therefore, in the embodiment of the present invention, a spring is used as the first elastic body, a damper is used as the second elastic body, and the spring and the damper function as a pair in the circumferential direction. Can be promoted with a damper, and aged deterioration of the damper can be compensated with a spring.

  Since it has been confirmed by experiment that the angular velocity fluctuations of the pulley unit 1 are absorbed and are not easily transmitted to the rotor shaft 3, it will be described below.

  The operating conditions are such that the pulley unit 1 is mounted on an alternator attached to the engine, the alternator rotational speed is 2000 rpm, and the load current of the alternator is set to 5 amperes.

  As shown in the graph of FIG. 4, even when the angular velocity of the pulley 2 fluctuates minutely like a sine curve, the rotation waveform of the rotor shaft 3 can be confirmed by the smaller fluctuation range. ing. Further, as shown in FIG. 4, the fluctuation in tension between the tension side and the loose side of the belt wound around the pulley 2 is also suppressed.

  As described above, according to the embodiment of the present invention, the first spring 19 having a poor damping property and the second damper 22 having a good damping property are combined in the circumferential direction so as to act as a pair, and the second spring 20 and the damping property are obtained. By combining the first damper 21 excellent in the circumferential direction so as to act as a pair, the fluctuation in the angular velocity of the pulley 2 can be effectively absorbed, and the durability of the belt 8 can be improved.

Side surface sectional drawing which shows the whole structure of the pulley unit which concerns on the best form of this invention Front cross-sectional view of pulley unit showing the case of increasing fluctuation of pulley angular velocity Front cross-sectional view of pulley unit showing the case of decreasing fluctuation of pulley angular velocity Rotation waveform diagram of pulley and rotor shaft as the pulley angular speed changes

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pulley unit 2 Pulley 3 Rotor shaft 4 Power transmission device 5, 6 Rolling bearing 8 Belt 15 Drive side 1st convex part 16 Drive side 2nd convex part 17 Driven side 1st convex part 18 Driven side 2nd convex part 19 1st Spring 20 Second spring 21 First damper 22 Second damper

Claims (3)

  A power transmission device that transmits rotational power between both inner and outer rings arranged concentrically, and having a radially inward convex portion on the inner peripheral surface of the outer ring and a diameter on the outer peripheral surface of the inner ring. Rotation torque based on rotational fluctuations of the annular body in at least one of the storage spaces is provided so that convex portions outward in the direction are arranged alternately in the circumferential direction to form a plurality of storage spaces between the circumferential directions of the convex portions A power transmission device characterized in that a spring is housed so as to receive vibration, and a damper is housed in at least one so as to attenuate vibration of the spring.   The power transmission device according to claim 1, wherein the storage space is disposed at a position facing the radial direction, and a spring and a damper are stored in the storage space arranged to face each other.   The outer ring is constituted by an alternator pulley having a belt winding part on the outer periphery and a belt for transmitting the rotational power of the engine is wound on the belt winding part, while the inner ring is formed by the pulley. The power transmission device according to claim 1, wherein the power transmission device is configured by an alternator rotor shaft disposed radially inward.

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