JP2005337378A - Power transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively absorb rotation fluctuation by damper effect of fluid. <P>SOLUTION: This power transmission is equipped with two rotating bodies 1 and 2 arranged radially inward and outward of themselves mutually, and an annular transmitting body 4 provided in an annular space 5 between the rotating bodies 1 and 2 confronting with each other so as to be displaced along the axial direction in a state of being fitted to the rotating bodies 1 and 2. The fluid 7 is filled and sealed in the annular space 5, and an orifice 4a making the fluid 7 communicate from one side to the other side in the axial direction of the annular transmitting body 4 is formed on a member abutted to the fluid 7 such as the annular transmitting body 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power transmission device, and more particularly to a power transmission device that can extract an output rotation with little fluctuation from an input rotation including fluctuation such as pulsation.

  A vehicle such as an automobile is equipped with an alternator, an air conditioner compressor, a water pump, a cooling fan, and the like as auxiliary machines driven from a crankshaft of an engine via a belt. When the rotational power of the engine is transmitted to such an auxiliary machine from the crankshaft through the belt, the belt tends to slip and generate abnormal noise due to fluctuations in the rotational speed of the crankshaft.

  This will be explained by taking an alternator as an example of an auxiliary machine as an example. Due to the operation process of the engine, the crankshaft always varies in its rotational speed during its rotation. On the other hand, since the rotor of the alternator has a large rotational inertia, an inertia torque is applied to the rotor. For this reason, when the rotor of the alternator is driven by a crankshaft with fluctuations in rotational speed, the loose side and the tension side of the belt are alternately switched to generate a fluctuation in tension, and the inertia torque of the rotor is applied to the belt. As a result, the belt is liable to slip and generate abnormal noise, or the durability tends to decrease.

  Therefore, conventionally, a power transmission device has been proposed in which a one-way clutch is provided as a power transmission member between a rotor shaft of an alternator and a pulley around which the belt is wound (see Patent Document 1).

  However, in the one-way clutch type power transmission device, the clutch locked state and the free state are repeated according to the fluctuation of the input rotation, and the non-transmission state is interposed between the transmission states. When switching from the free state to the locked state due to large rotational fluctuations on the input side, the rollers and sprags as the wedge members suddenly engage with each other, so relatively large fluctuations appear in the rotation on the output side, and the effect of absorbing rotational fluctuations Is insufficient.

For such a one-way clutch-type power transmission device, an annular transmission body that is axially displaceable in a state where the power transmission member is fitted in a rotational direction between the pulley and the rotor shaft, It is composed of coil springs arranged on both sides in the axial direction of the annular transmission body, and the annular transmission body is displaced in the axial direction against the spring force of the coil spring in accordance with fluctuations in the input rotation to absorb rotational fluctuations. A spring-type power transmission device has been proposed.
JP 2001-90751 A

  In the case of the spring-type power transmission device, it is necessary to adjust the spring constant in order to set the pressing force of the coil spring that presses the annular transmission body in the axial direction to a required value. However, it is not always easy, and when the spring constant is set to a large value, it is necessary to change the diameter of the pulley or the rotor shaft. Further, if the spring constant is not adjusted properly, the coil spring may be damaged due to plastic deformation by the annular transmission that is displaced in the axial direction.

  A power transmission device according to the present invention is a power transmission device including two rotating bodies arranged to face radially inward and outward, and a power transmitting portion provided in an annular space between the both rotating bodies, The outer rotating body includes a first fitting portion having one of a spiral shape and a linear shape on the inner peripheral surface, and the inner rotating body has the other of the spiral shape and the linear shape on the outer peripheral surface. The power transmission unit includes a third fitting part having a shape corresponding to the first fitting part on an outer peripheral surface, and the second fitting part on an inner peripheral surface. Each annular transmission body having a shape corresponding to the portion, and a fluid that is filled and sealed in the annular space so as to exist on both sides in the axial direction of the annular transmission body, and is in contact with the fluid The member is formed with an orifice through which the fluid flows from one axial side to the other side of the annular transmission. And it is characterized in that is.

  According to the above configuration, in a state where the rotation of the driving-side rotator is steady and the rotation is transmitted to the driven-side rotator via the annular transmission, the annular transmission is almost in the annular space. A fluid is present on both axial sides at an axially intermediate position.

  Here, if the rotational speed of the rotating body on the driving side varies, the annular transmission body is displaced to one side in the axial direction. At this time, since the annular transmission member pressurizes the fluid existing on one side in the annular space like the piston in the cylinder, the fluid existing on one side is formed in the annular transmission member or the like. It flows to the other side of the annular transmission through the orifice. At this time, the flow resistance when the fluid flows through the orifice becomes a resistance against the axial displacement of the annular transmission, and the rotational fluctuation is attenuated by this resistance.

  The damping action against the rotational fluctuation can be easily adjusted by appropriately setting the diameter and number of orifices, the viscosity of the fluid, and the like.

  In the power transmission device having the above-described configuration, the orifice can be formed in a member in contact with the fluid, for example, an outer rotator or an inner rotator, and may be a hole that penetrates the annular transmission member in the axial direction. desirable. The orifice formed in the annular transmission body is straight and short, and it is not necessary to perform troublesome processing for formation.

  Moreover, it is desirable to use lubricating oil as the fluid. Lubricating oil penetrates into the helical fitting portion and the linear fitting portion between the annular transmission body and the rotating body to lubricate the portion, thereby preventing wear of each fitting portion and the annular transmission body. This has the effect of smoothing the movement of

  Since fluctuations in one direction of the input rotation are usually accompanied by fluctuations in the other direction, the annular transmission often returns to an intermediate position in the axial direction. It is desirable to provide a return spring that returns to a predetermined intermediate position. With such a return spring, the annular transmission is always pushed back to a predetermined intermediate position, and the annular transmission is shifted to one side in the axial direction in the annular space, and its axial movement is restricted. There is no such thing.

  According to the present invention, the rotation fluctuation is effectively absorbed by the damper action due to the flow resistance of the fluid, and the output rotation with little fluctuation is obtained.

  The best mode of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a sectional view of a half of the power transmission device according to the best embodiment, and FIG. It is a perspective view of the annular transmission which is a part of. The power transmission device is installed in an input unit of an alternator that is an auxiliary machine for an engine of an automobile or the like.

  Referring to these drawings, a pulley (drive-side rotator) 1 has a pulley groove 1a around which a belt (not shown) wound around an outer peripheral surface of the pulley (not shown) is wound. The surface is provided with a straight spline (linear fitting portion) 1s that is linear in the axial direction as a first fitting portion. The rotor shaft (driven rotor) 2 is arranged on the radially inner side of the pulley 1 and includes a helical spline (spiral fitting portion) 2n as a second fitting portion on the outer peripheral surface.

  The rolling bearing 3 is a deep groove ball bearing with a seal 3a that supports the rotor shaft 2 on the pulley 1. The rolling bearing 3 is provided on the step portion 2a on the outer peripheral surface of the rotor shaft 2, and is fixed in the axial direction by a retaining ring 2b. The pulley 1 is positioned in the axial direction with respect to the rotor shaft 2, and the space between the facing portions of the pulley 1 and the rotor shaft 2 is sealed on one axial side (the right side in FIG. 1). On the other side in the axial direction (left side in FIG. 1), a seal 6 that seals a gap between the pulley 1 and the inner diameter edge 1 b of the pulley 1 is provided.

  The annular transmission 4 is provided in an annular space 5 between the outer peripheral surface of the rotor shaft 2 and the inner peripheral surface of the pulley 1 in a state that can be displaced in a certain range in the axial direction. The rotational power of the pulley 1 can be transmitted to the rotor shaft 2 while absorbing fluctuations such as pulsation included in the input rotation.

  That is, the annular transmission 4 is provided with a helical spline (spiral fitting portion) 4n spiraling in the axial direction corresponding to the helical spline 2n of the rotor shaft 2 as a third fitting portion on the inner peripheral surface, The outer peripheral surface is provided with a linear spline (linear fitting portion) 4s that is linear in the axial direction corresponding to the linear spline 1s of the pulley 1 as a fourth fitting portion.

  In the above configuration, in the present embodiment, the power transmission portion provided between the pulley 1 and the rotor shaft 2 is arranged in the annular space 5 so as to exist on both sides of the annular transmission body 4 and the annular transmission body 4 in the axial direction. And a fluid 7 filled and sealed.

  As the fluid 7 filled in the annular space 5, a synthetic lubricating oil such as silicon oil or ester oil, or a mineral oil based lubricating oil is used. In addition, a viscous fluid such as ethylene glycol may be used, and a gas may be used when a high degree of sealing performance can be secured. In addition, since the input part of an alternator may become comparatively high temperature, it is desirable that the fluid 7 to be used has heat resistance.

  The annular transmission body 4 is formed with an orifice 4a penetrating in an axial direction from one side surface to the other side surface. The orifice 4a is for circulating the fluid 7 existing on one side in the axial direction of the annular transmission 4 to the other side. A plurality of orifices 4a are arranged at equal intervals in the circumferential direction of the annular transmission 4, and three in the illustrated example. Is formed.

  In the annular space 5, return springs 8 and 9 are provided on both sides in the axial direction of the annular transmission 4 to return the annular transmission 4 to an intermediate position in the axial direction. The return springs 8 and 9 may be other types of springs such as a disc spring, but a coil spring is used in the illustrated example. Out of the return springs 8 and 9 on both sides in the axial direction, the outer end of the return spring 8 provided on one side (left side in FIG. 1) of the annular transmission 4 is a spring receiver 10 that contacts the inner diameter edge 1 b of the pulley 1. It is accepted by. The return spring 9 provided on the other side (right side in FIG. 1) is received by a spring receiver 11 that abuts against the inner ring of the rolling bearing 3.

  In the above configuration, when the pulley 1 rotates, the rotation is transmitted to the rotor shaft 2 via the annular transmission body 4, and the rotor shaft 2 rotates in the same direction. When the pulley 1 is steadily rotating, the annular transmission 4 is at the axial intermediate position shown in FIG. 1, and the rotation of the pulley 1 is transmitted to the rotor shaft 2 as it is. Rotates in sync with 1.

  If the rotation of the pulley 1 suddenly fluctuates in the speed increasing direction (the front side indicated by the arrow a in FIG. 1), the annular transmission 4 tries to follow the rotation of the pulley 1 and the annular transmission 4 and the rotor shaft 2. Are moved forward in the rotational direction A along the spiral splines 4n and 2n between them, and as a result, are displaced in one axial direction (leftward in FIG. 1).

  At this time, the annular transmission 4 pressurizes the fluid 7 existing on one side (left side) in the annular space 5, and the fluid 7 existing on the same side passes through the orifice 4 a formed in the annular transmission 4. It flows to the other side (right side) of the annular transmission 4. At this time, the flow resistance when the fluid 7 flows through the orifice 4 a becomes resistance to the axial displacement of the annular transmission 4 and suppresses the axial displacement of the annular transmission 4. Further, the sliding force on the spiral spline 4n and the linear spline 4s and the restoring elasticity of the return spring 8 on one side act on the annular transmission body 4.

  As described above, the annular transmission 4 is displaced in the axial direction against the flow resistance of the fluid 7, the sliding resistance of the spiral spline 4n, and the restoring elasticity of the return spring 8, and during this displacement, the pulley The rotation of the rotor shaft 2 is delayed with respect to 1, and the sudden acceleration of the rotation of the pulley 1 is hardly transmitted to the rotor shaft 2. In short, the rotational fluctuation included in the input rotation is absorbed as energy for displacing the annular transmission 4 in the axial direction. Therefore, the action of a sudden tension on the belt due to the rotation fluctuation can be prevented, and the life of the belt and the pulley 1 can be extended.

  When the rotation of the pulley 1 suddenly fluctuates in the deceleration direction (the direction indicated by arrow B in FIG. 1), the annular transmission 4 flows through the orifice 4a of the annular transmission 4 in an attempt to follow the rotation of the pulley 1. Against the flow resistance at the time of sliding, the sliding resistance of the spiral spline 4n, etc., and the restoring elasticity of the return spring 9, it moves in the deceleration direction B along the spiral splines 4n, 2n, and the other in the axial direction (FIG. 1). To the right), and by this displacement, fluctuations included in the rotation of the pulley 1 are absorbed.

  In the embodiment shown in FIGS. 1 and 2, the orifice for allowing the fluid 7 to flow from one side to the other side in the axial direction of the annular transmission 4 is formed in the annular transmission 4, but the orifice is as shown in FIG. In addition, a member in contact with the fluid 7, that is, the pulley 1 or the rotor shaft 2 can be formed.

  FIG. 3 is a cross-sectional view of a main part of a power transmission device according to another embodiment of the present invention. In FIG. 3, the orifice 1 c is formed on the inner peripheral side of the pulley 1 and has openings 1 cs and 1 ct that open into the annular space 5 outside the axial displacement range of the annular transmission 4. In this case, the orifice 4a passing through the annular transmission 4 in the axial direction is omitted, but the orifice 4a is also formed in the annular transmission 4 and the fluid 7 is passed through the orifice 4a and the orifice 1c on the pulley 1 side. You may make it distribute | circulate from the axial direction one side of the annular transmission 4 to the other side.

  Also in the above configuration, when the rotation of the pulley 1 suddenly fluctuates in the direction of acceleration or deceleration, the annular transmission body 4 resists the flow resistance when the fluid 7 flows through the orifice 1c of the pulley 1 in the axial direction. The displacement included in the rotation of the pulley 1 is absorbed by this displacement.

  In addition, you may form the orifice which distribute | circulates the fluid 7 from the axial direction one side of the cyclic | annular transmission body 4 to the other side in the rotor axis | shaft 2, as shown by the chain line in FIG. The orifice 2c has openings 2cs and 2ct which open into the annular space 5 outside the axial displacement range of the annular transmission.

  1 and 2, the annular transmission body 4 is fitted with a linear spline along the axial direction with the rotor shaft 2 on the inner peripheral side, and a helical spline with the pulley 2 on the outer peripheral side. You may make it fit by. The annular transmission 4 is fitted to the rotor shaft 2 by a helical spline 4n, and the pulley 1 is fitted to the helical spline 4n to the rotor shaft 2 by a helical spline in the reverse screw direction. Good. Furthermore, instead of the spiral spline provided between the transmission body 4 and the rotor shaft 2 or between the transmission body 4 and the pulley 1, it may be fitted with a screw having a large lead angle. In short, it is sufficient that at least one of the outer diameter side rotating body and the inner diameter side rotating body is fitted to the annular transmission body 4 by the helical fitting portion.

Sectional drawing of the half part of the power transmission device which concerns on best embodiment of this invention. The perspective view of the annular transmission body which is a part of apparatus of FIG. Sectional drawing of the principal part of the power transmission device which concerns on other embodiment of this invention.

Explanation of symbols

1 Pulley (drive-side rotating body)
1s linear spline (linear fitting part)
2 Rotor shaft (driven rotor)
2n Spiral spline (spiral fitting part)
4 Annular transmission 4s Linear spline (Linear fitting part)
4n Spiral spline (spiral fitting part)
4a Orifice 5 Annular space 7 Fluid 8, 9 Return spring

Claims (3)

A power transmission device comprising two rotators arranged oppositely on the radially inner side and the outer side, and a power transmission part provided in an annular space between the two rotators,
The outer rotating body includes a first fitting portion having one of a spiral shape and a linear shape on an inner peripheral surface, and the inner rotating body has a spiral shape and a linear shape on an outer peripheral surface. A second fitting portion having the other shape;
The power transmission portion has a third fitting portion having a shape corresponding to the first fitting portion on the outer peripheral surface, and a fourth fitting portion having a shape corresponding to the second fitting portion on the inner peripheral surface. Each of the annular transmissions, and a fluid filled and sealed in the annular space so as to exist on both sides in the axial direction of the annular transmissions,
The member in contact with the fluid is formed with an orifice through which the fluid flows from one side to the other side in the axial direction of the annular transmission.
A power transmission device characterized by that.   The power transmission device according to claim 1, wherein the orifice is a hole penetrating the annular transmission body in an axial direction.   The power transmission device according to claim 1, wherein the fluid is lubricating oil.

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