JP2005172051A - Power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce output rotation with less changes in speed increasing and reducing directions. <P>SOLUTION: This power transmission device transmits rotating torque between two rotors 1, 2 concentrically arranged to be relatively rotatable. It comprises a viscous fluid 4 filled in an annular space 3 between both rotors 1, 2 and flow resistance parts 7, 9 arranged in the annular space 3 between both rotors 1, 2 to produce flow resistance to the viscous fluid 4. One flow resistance part 7 is in a wavy shape and the other flow resistance part 9 is in a blade shape. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a power transmission device, and more particularly to a power transmission device suitable for extracting an output rotation with little fluctuation from an input rotation including fluctuations such as pulsation.

  Automobiles and the like are equipped with various auxiliary machines that are driven from a crankshaft of an engine via a belt. Such auxiliary machines include an alternator, an air conditioner compressor, a water pump, a cooling fan, and the like.

  When an auxiliary machine such as an alternator is driven directly by a belt that is fed in conjunction with the crankshaft of the engine, the rotation of the crankshaft includes fluctuations such as pulsation. Each time, the belt is subjected to sudden tension due to rotational fluctuations, causing slippage between the belt and the pulley on the accessory side, generating harsh noises and the life of the belt and pulley. May be shortened.

Therefore, conventionally, in an alternator, a power transmission device using a one-way clutch is provided between the input rotary shaft and a pulley around which a belt is wound (see Patent Document 1).
JP 2001-90751 A

  In the conventional power transmission device using the one-way clutch as described above, the one-way clutch is repeatedly locked and free in accordance with fluctuations in the input rotation, and a non-transmission state is interposed between the transmission states. It will be. When switching from the free state to the locked state due to a sudden rotation fluctuation on the input side, the rollers and sprags as the wedge members will be engaged, and there will be a relatively large fluctuation with a sharp rise in the rotation on the output side. There is a problem that the effect of absorbing rotational fluctuation is insufficient.

  In addition, the power transmission device described above can cope with fluctuations in one direction as in the case of acceleration, but cannot sufficiently cope with fluctuations in rotation during deceleration in the other direction. The effect is insufficient.

  A power transmission device according to the present invention is a power transmission device that transmits rotational torque between two rotating bodies arranged concentrically so as to be relatively rotatable, and includes a viscous fluid sealed in an annular space between both rotating bodies, A flow resistance portion disposed in the annular space of both rotating bodies, and the flow resistance portion is configured by a convex portion extending in the axial direction and projecting in the radial direction on at least one of the opposed peripheral surfaces of the both rotating bodies. It is characterized by being.

  According to the present invention, the flow resistance portion disposed in the annular space of both rotating bodies is constituted by the convex portion that extends in the axial direction and protrudes in the radial direction on at least one of the opposed peripheral surfaces of both rotating bodies. When transmitting the rotational torque of the rotating body on the side to the rotating body on the driven side via the viscous fluid, the rotating body on the driven side is the same as the rotating body on the driving side in the rotational direction. And the rotational torque fluctuation is absorbed by the damping action caused by the shear stress generated inside, so that the rotational torque of the driven rotor is reduced. The transmission of fluctuations is effectively blocked or suppressed.

  JP-A-8-240246 discloses a technique in which a viscous fluid is put between both rotating bodies and a plurality of convex portions constituting a labyrinth portion are provided on opposing circumferential surfaces of both rotating bodies. The plurality of convex portions do not extend in the axial direction in order to form a labyrinth portion, and are continuous in the circumferential direction. There is no action as a part. On the other hand, the convex portion in the present invention extends in the axial direction and is not continuous in the circumferential direction. It can act effectively. Any viscous fluid can be used in principle as long as it is a fluid having viscosity, and can be included in the viscous fluid of the present invention, but silicon oil can be used particularly preferably.

  As a preferred embodiment of the present invention, a convex portion is provided on each of the opposed peripheral surfaces of both rotating bodies, on the one hand in a wave shape, and on the other hand in a blade shape, and the convex portions provided on both the rotating bodies are opposed to each other. It can be set as the structure which changes a clearance gap with the relative rotation of both rotary bodies.

  In such a case, the flow of the viscous fluid can be suppressed more effectively, and a large rotation delay can be prevented from occurring in the driven rotor relative to the rotation on the driving side, and a large torque can be transmitted with a small rotation delay. be able to.

  When the power transmission device of the present invention is applied to a pulley unit, the outer diameter side rotating body may be configured integrally with the pulley or separately, and the inner diameter side rotating body may be configured as a rotating shaft. It may be configured integrally or separately. In the above case, the pulley itself becomes the outer diameter side rotator, the belt is wound around the outer peripheral surface thereof, and the rotation shaft becomes the inner diameter side rotator itself, and the pulley inner surface and / or the outer peripheral surface of the rotation shaft. The convex portion may be provided. When integrated, the cost can be reduced as compared with a separate configuration.

  According to the present invention, the rotational fluctuation in the acceleration direction and the rotational fluctuation in the deceleration direction are both absorbed or suppressed by the damping action of the viscous fluid, and an output rotation with little fluctuation is obtained.

  The best embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view taken along the axial direction of the power transmission device according to the best embodiment, and FIG. 2 is a cross-sectional view taken along line (2)-(2) in FIG.

  The power transmission device according to this embodiment is provided as an example of a pulley unit at an input portion of an alternator that is an auxiliary machine of an engine such as an automobile, and includes an outer diameter side rotating body 1 and an inner diameter side rotation. The body 2 and the viscous fluid 4 enclosed in the annular space 3 which these rotary bodies 1 and 2 oppose are provided.

  The outer diameter side rotator 1 is a cylindrical rotator on the driving side, and a pulley 5 is fitted and fixed to the outer periphery thereof. The pulley 5 has a pulley groove 5a on the outer peripheral side. The belt 6 is fed in conjunction with the crankshaft of the engine and is wound around the pulley groove 5a.

  The outer diameter side rotating body 1 includes inner flange portions 1a and 1b that protrude inward in the radial direction on both axial sides of the inner periphery. Between these inner flanges 1a and 1b, as a first flow resistance part for the viscous fluid 4, a waveform resistance part 7 swelled in a waveform in the annular space 3 is formed as an example of one convex shape. . The corrugated resistance portion 7 has a wave shape in which a plurality of convex portions extending in the axial direction and projecting in the radial direction are continuously curved, and is brought into contact with the viscous fluid 4 so that friction with the viscous fluid 4 occurs. Resistance is increasing. The protruding height of the waveform resistor portion 7 is set to be equal to or less than the inner peripheral surface of the inner flange portions 1a and 1b.

  Both the inner flange portions 1a and 1b may be formed integrally with the axial intermediate portion of the outer diameter side rotating body 1 as in the left inner flange portion 1a in FIG. Like the portion 1 b, it is configured as an annular body separate from the axial intermediate portion of the outer diameter side rotating body 1, and the separate inner flange portion 1 b is fixed to the axial intermediate portion of the outer diameter side rotating body 1. May be.

  The inner diameter side rotating body 2 is a substantially cylindrical rotating body on the driven side, and an input rotating shaft 8 of an alternator is inserted into and fixed to the inner periphery thereof. The inner diameter side rotator 2 includes outer flange portions 2a and 2b that are radially outward on both axial sides of the outer periphery. Between these outer flange portions 2a and 2b, as a second flow resistance portion, a blade resistance portion 9 is provided that crosses the annular space 3 in the shape of a blade in the axial direction as an example of the other convex shape. The blade resistance portion 9 is a blade-like projection that extends in the axial direction and protrudes in the radial direction, and narrows the flow path of the viscous fluid 4 in the gap facing the waveform resistance portion 7. Yes. A plurality of blade resistance portions 9 are provided at regular intervals in the circumferential direction, and three blade resistance portions 9 are provided in the illustrated example. The protruding height of the blade resistance portion 9 is the same as or less than the outer peripheral surface of the outer flange portions 2a and 2b so as not to interfere with the waveform resistance portion 7.

  The outer flange portions 2a and 2b may be formed integrally with the intermediate portion in the axial direction of the inner diameter side rotating body 2 or may be formed separately from the intermediate portion in the axial direction of the inner diameter side rotating body 2 You may fix to the axial direction intermediate part of the rotary body 2. FIG.

  On the outer periphery of the inner diameter side rotating body 2, the outer diameter side rotating body 1 is externally fitted so as to be relatively rotatable. Between the inner and outer rotating bodies 1 and 2, the inner peripheral surfaces of the inner flange portions 1a and 1b are fitted to the outer peripheral surfaces of the outer flange portions 2a and 2b through a lubricating film made of a lubricant. An annular space 3 in which both axial sides are closed is formed between the inner and outer rotating bodies 1 and 2 by the fitting.

  Between the outer flange portions 2a and 2b and the inner flange portions 1a and 1b, a rolling bearing 10 or a slide bearing is interposed. By such a bearing 10, the outer diameter side rotating body 2 is rotated on the outer diameter side. The body 1 is supported so as to be relatively rotatable with the body 1 positioned in the axial direction.

  As the viscous fluid 4, silicon oil is preferable. As another example of the viscous fluid 4, a dilatancy fluid whose viscosity is greatly increased by shearing or stirring may be used.

  In the power transmission device having the above-described configuration, the rotational torque is transmitted to the inner diameter side rotating body 2 via the waveform resistance portion 7, the viscous fluid 4, and the blade resistance portion 9 on the inner periphery of the outer diameter side rotating body 1. When the input rotation is steady, the flow resistance of the waveform resistance unit 7 and the blade resistance unit 9 is large. Therefore, the inner diameter side rotating body 2 is almost integrated with the outer diameter side rotating body 1 in the rotation direction, and the outer diameter side rotation is performed. Rotates at almost the same speed as body 1. When fluctuations occur in the input rotation, the fluctuations are absorbed by the damping action caused by the shear stress generated in the viscous fluid 4 and hardly transmitted to the inner diameter side rotating body 2.

  In this case, since the damping action of the viscous fluid 4 works in any direction, both the rotational fluctuation in the acceleration direction and the rotational fluctuation in the deceleration direction are both absorbed or suppressed.

  Further, as in the above embodiment, the outer diameter side rotating body 1 is configured as a separate cylinder from the pulley 5, and the inner diameter side rotating body 2 is configured as a separate cylinder from the input rotary shaft 8. When the outer diameter side rotating body 1 and the inner diameter side rotating body 2 are combined in the radial direction inside and outside, and the viscous fluid 4 is filled and sealed between them, the entire power transmission device is assembled into a cylindrical shape. Unit. The unitized power transmission device can be fitted and fitted from the outside in the axial direction between the inner circumferential surface of the pulley 5 and the outer circumferential surface of the input rotary shaft 8, and can be installed at the equipment location. Easy to do.

  In the above embodiment, the flow resistance portions (waveform resistance portion 7 and blade resistance portion 9) are provided on the inner and outer rotary bodies 1 and 2, respectively, but it is not always necessary to provide the flow resistance portions on both the rotary bodies 1 and 2, As shown in another embodiment of FIG. 3, a flow resistance portion may be provided only on one rotating body 1 (2).

  In another embodiment of FIG. 3, the inner peripheral surface 1c of the outer diameter side rotating body 1 is formed on an inner peripheral surface having a constant inner diameter without any irregularities. On the other hand, a blade resistance portion 9 is provided on the outer periphery of the inner diameter side rotating body 2 so as to cross the annular space 3 in a plate shape in the axial direction. The flow gap 11 of the viscous fluid 4 is narrower than the radial width of the annular space 3 between the outer peripheral surface of the blade resistance portion 9 and the inner peripheral surface 1c of the outer diameter side rotating body 1. Is formed.

  In this configuration, the flow of the viscous fluid 4 with respect to the outer diameter side rotating body 1 is suppressed by the narrow flow gap 11 between the rotating bodies 1 and 2, and the movement of the blade resistance unit 9 in the rotational direction with respect to the viscous fluid 4 is also suppressed. Therefore, the inner diameter side rotating body 2 is more strongly coupled to the outer diameter side rotating body 1 in the rotation direction, and the inner diameter side rotating body 2 does not have a large rotation delay with respect to the rotation of the outer diameter side rotating body 1. . Further, a large torque can be transmitted with a small rotational delay.

  In each of the above embodiments, the inner and outer rotating bodies 1 and 2 are separate from the pulley 5 and the input rotary shaft 8. However, these rotating bodies 1 and 2 are connected to the pulley 5 and the input. It is good also as an integral thing of the same material as the rotating shaft 8 for an object. That is, the inner flange portions 1a and 1b constituting the outer diameter side rotating body 1 and the waveform resistance portion 7 are integrally formed directly on the inner periphery of the pulley 5, and the inner diameter side rotation is directly performed on the outer periphery of the input rotary shaft 8. The outer flange portions 2a, 2b constituting the body 2 and the blade resistance portion 9 may be integrally formed.

  In contrast to the embodiment of FIGS. 1 and 2, the blade resistance portion 9 may be provided on the inner periphery of the outer diameter side rotating body 1, and the waveform resistance portion 7 may be provided on the outer periphery of the inner diameter side rotating body 2. In addition, for the inner flange portions 1a and 1b and the outer flange portions 2a and 2b, the protruding height of one of the flange portions 1a and 1b (or 2a and 2b) is increased, and the other flange portions 2a and 2b (or 1a and 1b) may be omitted.

  The present invention can be used not only for engine auxiliary machines but also for power transmission units that need to absorb and suppress rotational fluctuations.

The axial direction sectional view of the power transmission device concerning the best embodiment of the present invention. Sectional drawing along the (2)-(2) line | wire of FIG. The axial direction sectional view of the important section of the power transmission device concerning other embodiments of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer diameter side rotary body 2 Inner diameter side rotary body 3 Annular space 4 Viscous fluid 7 Waveform resistance part (1st flow resistance part)
9 Blade resistance part (second flow resistance part)

Claims (2)

A power transmission device that transmits rotational torque between two rotating bodies arranged concentrically so as to be relatively rotatable,
A viscous fluid sealed in an annular space between both rotating bodies;
A flow resistance portion disposed in the annular space of both rotating bodies,
The flow resistance portion is constituted by a convex portion that extends in the axial direction and protrudes in the radial direction on at least one of the opposed peripheral surfaces of both rotating bodies.   Convex portions are provided on each of the opposed peripheral surfaces of both rotating bodies on the one hand in a wave shape, and on the other hand in a blade shape. The power transmission device according to claim 1, wherein the power transmission device is configured to change with relative rotation.

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