JP2005233300A - Power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To absorb a variation in rotational angular velocity efficiently at the time of transmitting the power. <P>SOLUTION: The power transmission device is equipped with an intermediate ring member 5 for transmission of the power and a plurality of rolling elements 6 in lieu of one-way clutch as conventional which are interposed between a pulley 2 and a rotor shaft 3 in order to absorb the variation in the rotational angular velocity of the pulley 2. The confronting surfaces of the pulley 2 and the intermediate ring member 5 and the rotor shaft 3 are shaped elliptically, and the variation in the rotational angular velocity of the pulley 2 is absorbed while the intermediate ring member 5 makes twisting deformation within the elasticity region in the circumferential direction in association with the variation in the rotational angular velocity of 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.

  Accordingly, a pulley around which the transmission belt is wound and a rotor shaft connected to the rotor of the alternator so as to be integrally rotatable are incorporated, and is incorporated between the pulley and the rotor shaft to respond to fluctuations in the rotational angular velocity of the pulley. Conventionally, a pulley unit including a one-way clutch that transmits or blocks rotational power from the pulley to the rotor shaft has been proposed (see, for example, Patent Document 1). In the pulley unit, the one-way clutch is locked according to the fluctuation in the rotational angular velocity of the pulley (when the rotation speed on the crankshaft side is larger than the rotation speed on the rotor side, the pulley and the rotor shaft are rotated together) ) Or in a free state (when the rotation speed on the crankshaft side is smaller than the rotation speed on the rotor side, the pulley and rotor shaft can be rotated relative to each other so that the rotor shaft can rotate freely by inertia) and the crankshaft rotates. Even if there is a slight change in angular velocity, the rotational fluctuation of the rotor shaft is suppressed to reduce the torque borne by the transmission belt, to prevent the generation of noise due to the slippage of the transmission belt, and to improve the durability of the transmission belt. It is possible to increase.

By the way, in the pulley unit using the one-way clutch described above, the power generation torque of the alternator (torque acting in the direction opposite to the inertia torque) is larger than the inertia torque of the rotor of the alternator. Then, in spite of the state in which the rotor is capable of inertial rotation in the free state, the rotor changes in rotation almost following the decrease in the minute change in the rotation angular velocity. There is a problem that it is impossible to absorb the minute fluctuations of. Therefore, in the pulley unit provided with the one-way clutch, there is a limit to the absorption of minute fluctuations in rotational angular velocity, and a pulley unit that can sufficiently absorb minute fluctuations in rotational angular velocity is desired.
JP 2001-90751 A

  The present invention relates to a power transmission device such as a pulley unit provided with an outer ring body such as a pulley and an inner ring body such as a rotor shaft. An object of the present invention is to make it possible to efficiently absorb the minute fluctuations in the rotational angular velocity described above based on a new idea of causing the intermediate ring body to act like a torsion spring during power transmission.

  The present invention is a power transmission device comprising 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 between the outer ring body, An intermediate ring that mediates transmission of rotational power is arranged between the outer ring and the inner ring, and the shapes of the opposing peripheral surfaces of the three rings are the rotation of the outer ring or the inner ring. The intermediate ring is twisted and deformed in the elastic region in accordance with minute fluctuations in angular velocity, and has a non-circular shape capable of transmitting rotational power.

  The non-circular shape is preferably an elliptical shape or a polygonal shape. In addition, there are cases where the outer ring is on the rotational power input side and the inner ring is on the rotational power output side, and vice versa. The inner ring body may be hollow or solid.

  According to the present invention, for example, when the rotational power input to the outer ring varies in a predetermined cycle, the intermediate ring rotates in the elastic direction in the elastic region when the rotation angular velocity of the outer ring increases. On the other hand, when the rotational angular velocity of the outer ring decreases, the intermediate ring twists and deforms in the elastic region in the reverse rotation direction. Due to the twist of the intermediate ring, the rotational power is transmitted from the outer ring to the inner ring with a delay, so the fluctuation of the rotational angular velocity of the outer ring is efficiently absorbed and the rotation fluctuation of the inner ring is suppressed. It becomes possible. In addition, the present invention has a simple configuration using an intermediate ring and a plurality of rolling elements as required, instead of the one-way clutch of the conventional example, and the cost can be reduced.

  A concave portion is formed on one of the opposed peripheral surfaces, and a convex portion is formed on the other, leaving a required circumferential play in the concave portion, and the rotational direction of the concave portion and the convex portion is increased when minute fluctuations in rotational angular velocity are increased. It is preferable that the rear end side has a structure in which the front end side can come into contact with each other when minute fluctuations in the rotational angular velocity are reduced. In this case, when the rotational angular velocity of the outer ring increases, the rear end side in the rotation direction of the concave part and the convex part comes into contact with each other to generate a load along the radial direction, so that the shape of the intermediate ring is made more distorted. The intermediate ring is easily twisted, but when the rotational angular velocity of the outer ring is reduced, the front end side in the rotation direction of the concave portion and the convex portion abuts to generate a load along the radial direction, thereby making the shape of the intermediate ring circular. The intermediate ring is easily rotated relative to the outer ring by acting so as to approach each other. Thereby, the effect which absorbs the rotation angular velocity fluctuation | variation of an outer ring body increases.

  The outer ring is a pulley around which a transmission belt for power transmission is wound from the crankshaft of the engine, and a pulley in which a plurality of rolling elements are rotatably arranged between the intermediate ring and the inner ring. It can be a unit structure.

  In the present invention, the efficiency and 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 member, a small variation of the rotational angular velocity above Can absorb well.

  The best mode for carrying out the present invention will be described below with reference to the drawings. 1 is a cross-sectional view of the pulley unit along the axial direction, and FIG. 2 is a cross-sectional view taken along line (2)-(2) in FIG. The present invention will be described as applied to a pulley unit as a power transmission device.

  As shown in the figure, a pulley unit 1 includes a pulley 2 as an outer ring and a rotor 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. Power transmission interposed between the shaft 3, the rolling bearing 4 disposed on the base end side of the rotor shaft 3 between the rotor shaft 3 and the pulley 2, and the opposed peripheral surfaces of the rotor shaft 3 and the pulley 2. Intermediate ring body 5, rolling elements 6 such as a plurality of rollers, and seals 7 and 8 that seal the space in which rolling bearing 4 and rolling elements 6 are arranged from the outside. Although not shown, a lubricant is accommodated in the space sealed by the seals 7 and 8.

  On the outer peripheral surface of the pulley 2, a wavy groove for winding the transmission belt 9 is formed. Although not shown, the rotor shaft 3 is connected to, for example, a rotating shaft of an auxiliary machine provided in an automobile or a crankshaft of an engine. The rolling bearing 4 includes a plurality of balls 4a and a cage 4b as rolling elements, and uses the intermediate ring 5 as an outer ring member and the rotor shaft 3 as an inner ring member.

  The inner peripheral surface shape of the pulley 2 is formed in a non-circular shape, preferably an elliptical shape. Concave portions 2 a that are recessed outward in the radial direction are provided at several circumferential positions (for example, two locations facing each other at 180 degrees) on the inner peripheral surface of the pulley 2.

  The shape of the outer peripheral surface of the rotor shaft 3 is formed in an elliptical shape as a non-circular shape having the same curvature as the inner peripheral surface shape of the pulley 2. The minimum diameter portion of the inner circumferential surface of the rotor shaft 3 is formed in a circular shape, and a crankshaft of an engine and a rotating shaft of an auxiliary machine provided in an automobile are connected to be integrally rotatable. A transfer groove 4 c for the ball 4 a of the rolling bearing 4 is provided on one axial end side (base end side of the rotor shaft 3) of the outer peripheral surface of the rotor shaft 3.

  The inner peripheral surface shape and the outer shape of the intermediate ring 5 are formed in an elliptical shape as a non-circular shape having the same curvature as the outer shape of the rotor shaft 3. The intermediate ring body 5 has a predetermined number of circumferential play h in the circumferential direction in the recess 2a of the pulley 2 by bulging outward in the radial direction at several circumferential positions (for example, two positions facing each other at 180 degrees) on the outer circumferential surface of the intermediate ring 5. The convex part 5a which can be inserted in the state which has is provided. Further, a transfer groove 4 d of the ball 4 a of the rolling bearing 4 is provided on one end side in the axial direction of the inner peripheral surface of the intermediate ring body 5 (base end side of the rotor shaft 3). The intermediate ring body 5 may be any material that can be elastically deformed, and can be formed of an appropriate metal, resin, rubber, or the like.

  The plurality of rolling elements 6 are interposed between the opposed peripheral surfaces of the rotor shaft 3 and the intermediate ring 5 in a state of being arranged at equal circumferential intervals by a cage 10. The cage 10 is provided with pockets penetrating radially inward and outward at several places on the circumference. A radially inward flange portion 10 a is provided on the other axial end side of the cage 10 (the free end side of the rotor shaft 3), and this flange portion 10 a is provided on the other axial end side of the rotor shaft 3 ( The cage 10 is positioned in the axial direction by being fitted into a groove provided on the outer peripheral surface on the free end side with a predetermined circumferential play.

  The concave portion 2a of the pulley 2 and the convex portion 5a of the intermediate ring 5 are provided in an appropriate angle range, for example, in a range of less than 180 degrees, preferably in a range of 10 degrees to 90 degrees. It is necessary to make the occupying angle of the concave portion 2a larger than the occupying angle of the convex portion 5a so that the convex portion 5a is fitted in a state having a predetermined circumferential play h in the circumferential direction. One end side in the circumferential direction of the concave portion 2a and the convex portion 5a is disposed at the maximum diameter portion (bulging portion) of the intermediate ring body 5, and the other circumferential side end of the concave portion 2a and the convex portion 5a is the intermediate ring body 5 side. It is arranged in the smallest diameter part.

  The operation of the pulley unit 1 will be described with reference to FIGS. 3 and 4. 3 is a cross-sectional view used for explaining the operation when the rotational angular velocity of the pulley unit 1 is increased, FIG. 4 is a cross-sectional view used for explaining the operation when the rotational angular velocity of the pulley unit 1 is decreased, and FIG. 5 is a diagram illustrating 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). In this case, the rotor shaft 3 is attached to the rotor of the alternator, and the pulley 2 is rotationally driven by a transmission belt 9 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. In general, since the crankshaft rotates and fluctuates at a predetermined cycle, the rotational angular velocity of the pulley 2 that is rotationally driven from the crankshaft through the transmission belt 9 fluctuates and fluctuates at a predetermined cycle. On the other hand, in this embodiment, since the rotation angular velocity fluctuation | variation of the pulley 2 can be absorbed efficiently and the rotation fluctuation | variation of the rotor shaft 3 can be suppressed, it demonstrates.

[1] When the rotational angular velocity of the pulley 2 increases In the rotational direction shown in FIG. 3, when the rotational angular velocity of the pulley 2 increases, the corner 2 c on the rear end side in the rotational direction of the recess 2 a of the pulley 2 A load F1 in the vertical direction is applied to the tapered surface 5c of the convex portion 5a in contact with the tapered surface 5c on the rear end side in the rotation direction. The intermediate ring 5 is elastically deformed so as to be twisted in the rotational direction by the component forces F2 and F3 of the load F1 and the power generation torque of the alternator applied to the rotor shaft 3, so that the rotational power is transferred from the intermediate ring 5 to the rotor shaft 3. Is transmitted with a delay. This twisting of the intermediate ring 5 is allowed by the circumferential play h provided between the recess 2 a of the pulley 2 and the protrusion 5 a of the intermediate ring 5. In addition, since the radially inward component force F2 acts to elastically compress the minimum diameter portion of the intermediate ring 5, the twist constant of the intermediate ring 5 is lowered. In this way, the increase in the rotational angular velocity of the pulley 2 is absorbed.

[2] When the rotational angular velocity of the pulley 2 decreases When the rotational angular velocity of the pulley 2 decreases in the rotational direction shown in FIG. 4, the rotor shaft 3 and the intermediate ring 5 are moved from the pulley 2 by the rotational inertia force of the rotor shaft 3. Further, the taper surface 5b on the front end side in the rotational direction of the convex portion 5a of the intermediate ring 5 comes into contact with the corner portion 2b on the front end side in the rotational direction of the concave portion 2a of the pulley 2, and Thus, a vertical load F4 is applied. Due to the component forces F5 and F6 of the load F4 and the moment of inertia of the rotor shaft 3, the intermediate ring 5 is elastically deformed to be twisted in the reverse rotation direction, and the rotational power is delayed from the intermediate ring 5 to the rotor shaft 3. Will be transmitted. The radially inward component force F5 acts so as to elastically compress the maximum diameter portion of the intermediate ring 5 and is elastically deformed so that the intermediate ring 5 approaches a circle. 5 becomes easier to rotate relative to the rotor shaft 3, and transmission of rotational power from the pulley 2 to the rotor shaft 3 is interrupted. In this way, the decrease in the rotational angular velocity of the pulley 2 is absorbed.

  When the power generation torque of the alternator is large, the rotational resistance of the rotor shaft 3 increases. In this case, when the rotational angular velocity of the pulley 2 increases, the degree of elastic deformation and twisting of the intermediate ring 5 becomes larger than when the generator torque of the alternator is small, and further transmission of the rotational power to the rotor shaft 3 is further increased. Since the delay is caused, the rotational fluctuation of the rotor shaft 3 can be suppressed. On the other hand, when the rotational angular velocity of the pulley 2 decreases, the degree of elastic deformation of the intermediate ring 5 so as to compress the maximum diameter portion becomes larger than when the generator torque of the alternator is small. Since the inner peripheral surface and the outer peripheral surface of the rotor shaft 3 are made closer to a circular shape, the intermediate ring body 5 and the rotor shaft 3 can be rotated relative to each other via the rolling elements 6, and the power from the pulley 2 to the rotor shaft 3 is increased. The transmission is cut off. As described above, with the configuration of the present embodiment, in the case of the pulley unit using the conventional one-way clutch, even if the effect of suppressing the rotational fluctuation of the rotor shaft 3 serving as the inner ring body is reduced, the rotor shaft 3 Rotational fluctuation can be reliably suppressed.

  As described above, in this embodiment, the one-way clutch as in the conventional example is not used as a configuration for absorbing the rotational angular velocity fluctuation, but the torsion spring action in the elastic deformation region of the intermediate ring 5 as described above. By utilizing this, it is possible to more efficiently absorb the fluctuations in the rotational angular velocity of the pulley 2 more reliably than in the conventional example using a one-way clutch, so that fluctuations in the rotation of the rotor shaft 3 can be suppressed. As a result, the amount of fluctuation in tension between the tension side (downstream in the rotational direction) and the loose side (upstream in the rotational direction) of the transmission belt 9 wound around the pulley 2 can be reduced.

  In addition, the configuration that generates the torsion spring action also uses the intermediate ring 5 and the plurality of rolling elements 6, the inner peripheral surface shape of the pulley 2, the inner peripheral surface shape and the outer shape of the intermediate ring 5, Since the outer shape of the rotor shaft 3 is merely an elliptical shape, the cost can be reduced, such as a simpler configuration than when a conventional one-way clutch is used. The torsion spring constant can be adjusted by the elliptical curvature of the inner peripheral surface shape of the pulley 2, the inner peripheral surface shape and outer shape of the intermediate ring 5, and the outer shape of the rotor shaft 3.

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

  (1) Although not shown, for example, a rolling bearing can be provided between the pulley 2 and the rotor shaft 3 on the other axial end side of the intermediate ring 5 (the free end side of the rotor shaft 3).

  (2) As shown in FIG. 6, it can be set as the structure which eliminated the recessed part 2a of the pulley 2, and the convex part 5a of the intermediate | middle ring 5. In this case, when the rotational angular velocity of the pulley 2 fluctuates, the concave portion 2a and the convex portion 5a cooperate to be elastically deformed so as to compress the intermediate annular body 5. Since the moving body 6 cooperates and exhibits a torsion spring action, the same effect as the above-described embodiment can be obtained.

  (3) The outer shape of the rotor shaft 3, the inner peripheral surface shape and outer shape of the intermediate ring 5 and the inner peripheral surface shape of the pulley 2 can be polygonal. However, in the case of a polygon, the corners are rounded and chamfered. As an example of these shapes, for example, as shown in FIG. In this case as well, the concave portion 2a of the pulley 2 and the convex portion 5a of the intermediate ring 5 may or may not be provided. However, when provided, three combinations of the concave portion 2a and the convex portion 5a are required as shown in the figure. become. The concave portion 2a and the convex portion 5a generate a load that compresses the intermediate annular body 5 as indicated by the black arrow X when the rotational angular velocity increases and as indicated by the white arrow Y when the rotational angular velocity decreases.

  (4) The rolling elements 6 can be balls. In this case, it is preferable to provide ball transfer grooves on the inner peripheral surface of the intermediate ring 5 and the outer peripheral surface of the rotor shaft 3.

  (5) 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. In this case, it is necessary to arrange the intermediate ring 5 on the rotor shaft 3 side and the rolling element 6 on the pulley 2 side. The operation in this case is basically the same as in the above embodiment.

The figure which made the pulley unit which concerns on the best embodiment of this invention the cross section along the axial direction 1 is a cross-sectional view taken along line (2)-(2) in FIG. 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 The pulley unit which concerns on other embodiment of this invention, and is a figure corresponding to FIG. FIG. 6 is a view corresponding to FIG. 2 of a pulley unit according to still another embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Pulley unit, 2 ... Pulley, 2a ... Recessed pulley, 3 ... Rotor shaft, 4 ... Rolling bearing, 5 ... Intermediate ring, 5a ... Convex part of intermediate ring, 6 ... Rolling body.

Claims (5)

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,
An intermediate ring that mediates transmission of rotational power is disposed between the outer ring and the inner ring, and the shapes of the opposing peripheral surfaces of the three rings are the same as the outer ring or the inner ring. A power transmission device characterized in that the intermediate ring has a non-circular shape capable of transmitting rotational power by twisting and deforming in an elastic region in accordance with minute fluctuations in rotational angular velocity.   The power transmission device according to claim 1, wherein the non-circular shape is an ellipse.   The power transmission device according to claim 1, wherein the non-circular shape is a polygon.   A concave portion is formed on one of the opposed peripheral surfaces, and a convex portion is formed on the other, leaving a required circumferential play in the concave portion, and the rotational direction of the concave portion and the convex portion is increased when minute fluctuations in rotational angular velocity are increased. The power transmission device according to any one of claims 1 to 3, wherein the rear end side has a structure in which the front end side can come into contact with each other when minute fluctuations in rotational angular velocity are reduced.   The outer ring is a pulley around which a transmission belt for power transmission is wound from the crankshaft of the engine, and a pulley in which a plurality of rolling elements are rotatably arranged between the intermediate ring and the inner ring. 5. The power transmission device according to claim 1, wherein the power transmission device has a unit structure.

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