JP2007205379A - Pulley - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulley having improved rotation fluctuation absorbing function. <P>SOLUTION: The pulley comprises a hub 5 fixed to a rotating shaft 3, a cylindrical pulley body 7 rotatably provided on the outer periphery of the hub 5, and a torque transmitting means 9 for transmitting torque between the pulley body 7 and the hub 5. The hub 5 has a cylindrical portion 11 to the inner peripheral face of which the rotating shaft 3 is fixed. The pulley body 7 is cylindrically formed, and the inner peripheral face of the pulley body 7 is isolated from the outer peripheral face of the cylindrical portion 11 to form a space portion 13. The torque transmitting means 9 is a spring 15 stored in the space portion 13 and having one end fixed to the pulley body 7 and the other end fixed to the hub 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pulley that is used in a winding transmission mechanism and that can absorb a belt tension variation caused by a rotational variation on a driving side.

  Patent Document 1 describes an auxiliary machine driving pulley that inputs engine torque to an auxiliary machine (air conditioner, power steering, alternator, water pump, etc.) via a belt.

  This accessory driving pulley has a hub fixed to the input shaft of the accessory, a pulley body rotatably provided on the outer periphery of the hub, and transmission of torque between the pulley body and the hub. Torque transmitting means for performing, and the torque transmitting means includes an elastic member.

In such an auxiliary machine driving pulley, torque including rotational fluctuation transmitted to the pulley main body via the belt is transmitted to the hub and the rotating shaft via the elastic member. Therefore, the rotational fluctuation is transmitted to the elastic member. The torque can be transmitted to the input shaft on the auxiliary machine side by absorbing the elastic deformation. Therefore, the fluctuation of the tension applied to the belt wound around the pulley body can be reduced, so that the life of the belt can be improved.
Japanese Patent Laying-Open No. 2004-232778 (FIG. 1)

  In the accessory driving pulley as described above, the torque transmission means includes a hub-side protrusion formed on the hub, a pulley-side protrusion formed on the pulley body, a hub-side protrusion, and a pulley-side protrusion. It is comprised with the elastic member accommodated in the formed space part. The elastic member used for such an accessory driving pulley is formed of a rubber material or the like.

  However, in the elastic member used for the accessory driving pulley as described above, if an excessive torque is input, the elastic member is crushed and the spring constant of the elastic member is significantly increased. For this reason, if an excessive torque is input, the fluctuation absorbing function of the elastic member may not work.

  Therefore, an object of the present invention is to provide a pulley that can improve the function of absorbing rotational fluctuation.

  The invention according to claim 1 is a hub fixed to a rotating shaft, a cylindrical pulley body rotatably provided on the outer periphery of the hub, and torque transmission means for transmitting torque between the pulley body and the hub. The hub includes a cylindrical cylindrical portion having an inner peripheral surface to which the rotation shaft is fixed, and the pulley main body is formed in a cylindrical shape, and the pulley main body has an inner peripheral surface and the pulley main body. A space portion is formed apart from the outer peripheral surface of the cylindrical portion, and the torque transmitting means is a spring that is housed in the space portion, one end portion is fixed to the pulley body, and the other end portion is fixed to the hub. It is characterized by being.

  The invention according to claim 2 is the pulley according to claim 1, wherein when an excessive torque is input to the hub or the pulley body, the spring is reduced in diameter and the spring of the cylindrical portion is reduced. An abutting control unit that abuts on the outer peripheral surface or a diameter of a spring that abuts on the inner peripheral surface of the pulley main body is formed.

  Since the pulley according to claim 1 uses a spring as a torque transmission means instead of a conventional elastic member formed of a rubber material or the like, even if an excessive torque is input, a change in the spring constant with respect to the torque is small. Therefore, fluctuation absorption is stable. Therefore, it is possible to absorb rotation fluctuations on the pulley main body side or the hub side, and to improve the function of absorbing rotation fluctuations.

  The spring has one end fixed to the pulley main body and the other end fixed to the hub to transmit torque between the pulley main body and the hub, so that the protrusion for transmitting torque to the pulley main body and the hub. It is not necessary to provide a transmission part such as a pulley, the configuration of the pulley can be simplified, and rotational fluctuations in both directions on the pulley main body side and the hub side can be absorbed.

  The pulley according to claim 2 has a contact control portion that contracts or expands when an excessive torque is input to the spring and contacts the outer peripheral surface of the cylindrical portion of the hub or the inner peripheral surface of the pulley body. Thus, when an excessive torque is input to the spring, the contact control unit functions as a stopper function, and the spring cannot be further deformed. For this reason, even if an excessive torque is input to the spring, the spring is not further deformed, and damage to the spring can be suppressed.

  The embodiment will be described with reference to FIGS.

  The pulley 1 according to this embodiment transmits a torque between the hub 5 fixed to the rotary shaft 3, a cylindrical pulley body 7 rotatably provided on the outer periphery of the hub 5, and the pulley body 7 and the hub 5. Torque transmitting means 9 for performing the above operation. Further, the hub 5 includes a cylindrical cylindrical portion 11 on the inner peripheral surface of which the rotation shaft 3 is fixed. The pulley main body 7 is formed in a cylindrical shape, and the inner peripheral surface of the pulley main body 7 and the outer peripheral surface of the cylindrical portion 11. The torque transmission means 9 is housed in the space 13 and is a spring 15 having one end fixed to the pulley body 7 and the other end fixed to the hub 5. The spring 15 is provided with a so-called coil spring.

  As shown in FIG. 1 and FIG. 2, the hub 5 is integrally formed with a cylindrical portion 11 having a cylindrical shaft portion 11 in which the tip end portion of the rotary shaft 3 is fixed to the inner peripheral surface by screwing, and an end portion on one side of the cylindrical portion 11. And a disc portion 17 formed as a matter of course. A hexagonal hole 19 into which a jig used when screwing the rotary shaft 3 is inserted is formed at the center of the disc portion 17. The disk portion 17 is formed with a fixing hole 21 for fixing a fixing portion 39 of a spring 15 which is a torque transmission means 9 described later. Further, the inner race 27 of the bearing 25 is press-fitted into the outer peripheral surface on the other side of the cylindrical portion 11 and the outer peripheral surface of the collar 23 press-fitted into the rotary shaft 3.

  The pulley body 7 is formed in a cylindrical shape, and includes a rim portion 29 around which a belt (not shown) is wound on an outer peripheral surface, and a fixing recess 33 to which a spacer 31 is press-fitted and fixed on an inner peripheral surface. The pulley body 7 is disposed on the outer periphery of the cylindrical portion 11 of the hub 5 so as to be separated. A space portion 13 is formed by the outer peripheral surface of the cylindrical portion 11 of the hub 5 and the inner peripheral surface of the pulley body 7. Further, an outer race 35 of the bearing 25 is press-fitted into one inner peripheral surface of the pulley body 7, and the spacer 31 is fixed by the outer race 35 and the fixing recess 33. Further, a fixing hole 37 for fixing the fixing portion 39 of the spring 15 is formed in the spacer 31, and the spring 15 that is the torque transmission means 9 is accommodated in the space portion 13.

  The spring 15 is formed with fixing portions 39 and 39 fixed to the fixing hole 21 of the hub 5 and the fixing hole 37 of the spacer 31 as spring hooking portions at both ends. Torque is transmitted between the hub 5 and the pulley body 7 by the fixing portions 39 and 39 and the fixing holes 21 and 37 of the hub 5 and the spacer 31. The shape of the spring hooking portion is not limited to the hole, and any shape may be used as long as both end portions of the spring 15 can be fixed. Further, the spring 15 is set so as to reduce or increase in diameter when a rotational difference occurs between the hub 5 and the pulley body 7, and the inner diameter side and the outer diameter side of the coil portion of the spring 15 are in contact with each other. 41 and 41 are formed. The contact control units 41 and 41 are configured such that when excessive torque is input between the hub 5 and the pulley body 7 so that the rotation fluctuation absorbing function by the spring 15 does not work, and the spring 15 is reduced in diameter, the cylindrical portion of the hub 5 When the spring 15 expands in diameter, it comes into contact with the inner peripheral surface of the pulley body 7. As a result, when an excessive torque is input so that the rotation fluctuation absorbing function by the spring 15 does not work, the contact control units 41 and 41 function as a stopper function, and the spring 15 cannot be further deformed. The characteristics of the spring 15 can be adjusted by the number of turns of the spring 15, the thickness of the line, and the like. Further, by applying grease to the spring 15 and coating with Teflon (registered trademark) or the like, abnormal noise or friction due to contact between the springs can be prevented.

  In the pulley 1 configured in this manner, when a moving force acts on a belt (not shown) due to rotation of a driving pulley (not shown), a torque is applied to the pulley body 7 of the pulley 1 by a frictional force with the belt (not shown). Is transmitted. Then, torque is transmitted from the pulley body 7 to the hub 5 via the spring 15. The rotation shaft 3 on the auxiliary machine (not shown) side is rotated by the rotation of the hub 5.

  In the rotation transmission process, when a rotation fluctuation occurs in the rotation on the driving side, the moving speed is changed so that a belt (not shown) follows the rotation fluctuation. On the other hand, since the hub 5 and the rotating shaft 3 try to rotate at a constant rotational speed due to inertia, a fluctuation in tension occurs in the belt (not shown). However, if there is a rotational fluctuation in the rotation of the pulley body 7, the spring 15 is elastically deformed and transmits the rotation to the hub 5 while absorbing the rotational fluctuation.

  Here, FIG. 3 shows a relationship between a conventional elastic body made of a rubber material and the like, a twist angle of the spring 15, and torque. In an elastic body, when an excessive torque is input or when the torsion angle increases, the spring constant increases suddenly, so the torque gradient with respect to the torsion angle is tight, and the range in which the function of absorbing rotational fluctuations works is narrow. It has become. On the other hand, in the spring 15, even when an excessive torque is input or the torsion angle becomes large, the spring constant is stable, and the inclination of the torque with respect to the torsion angle becomes gentle, so that the function of absorbing rotational fluctuations is achieved. The working range is very wide compared to conventional elastic bodies. For this reason, the spring 15 can absorb rotational fluctuations in a range that cannot be absorbed by a conventional elastic body.

  In such a pulley 1, a spring 15 is used as the torque transmitting means 9 instead of an elastic body formed of a conventional rubber material or the like, so that even if an excessive torque is input, the spring constant is stable. Thus, the rotational fluctuation on the pulley body 7 side or the hub 5 side can be absorbed, and the rotational fluctuation absorbing function can be improved.

  Further, since the torque between the pulley body 7 and the hub 5 is transmitted by the spring 15, it is not necessary to provide a transmission portion such as a protrusion for transmitting torque to the pulley body 7 and the hub 5, and only the spring 15 is provided. Thus, torque can be transmitted and the configuration of the pulley 1 can be simplified.

  Further, since the springs 15 are fixed to the pulley body 7 and the hub 5 at the both ends, the spring 15 can absorb rotational fluctuations in both directions on the pulley body 7 side and the hub 5 side.

  Further, when an excessive torque is applied to the spring 15 so that the rotational fluctuation absorbing function by the spring 15 does not work, the diameter of the spring 15 is reduced or increased, and the outer peripheral surface of the cylindrical portion 11 of the hub 5 or the inner surface of the pulley body 7 is reduced. Since the contact control parts 41 and 41 that contact the peripheral surface are formed, the contact control parts 41 and 41 serve as a stopper function when an excessive torque is input so that the rotation fluctuation absorbing function by the spring 15 does not work. The spring 15 can no longer be deformed. For this reason, even if an excessive torque is input so that the rotation fluctuation absorbing function by the spring 15 does not work, the spring 15 is not further deformed, and damage to the spring 15 can be suppressed.

FIG. 3 is a perspective view of a pulley according to the present embodiment. FIG. 3 is a cross-sectional view of a pulley according to the present embodiment. It is a figure showing the change of a twist angle and a torque.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pulley 3 ... Rotating shaft 5 ... Hub 7 ... Pulley main body 9 ... Torque transmission means 13 ... Space part 15 ... Spring 21 ... Fixed hole 31 ... Spacer 37 ... Fixed hole 39 ... Fixed part 41 ... Contact control part

Claims (2)

A pulley comprising a hub fixed to a rotating shaft, a cylindrical pulley body rotatably provided on the outer periphery of the hub, and a torque transmission means for transmitting torque between the pulley body and the hub. And
The hub includes a cylindrical cylindrical portion having an inner peripheral surface to which the rotation shaft is fixed. The pulley main body is formed in a cylindrical shape, and the inner peripheral surface of the pulley main body and the outer peripheral surface of the cylindrical portion are separated from each other. A space is formed,
The pulley is characterized in that the torque transmission means is a spring housed in the space, one end fixed to the pulley body and the other end fixed to the hub. The pulley according to claim 1,
When an excessive torque is input to the hub or the pulley main body, the spring contracts the diameter of the spring and comes into contact with the outer peripheral surface of the cylindrical portion, or the spring expands the diameter of the pulley main body. A pulley comprising an abutting control unit that abuts against an inner peripheral surface.

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