JP2013024293A - Pulley unit with built-in clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulley unit with a built-in clutch, which reliably prevents entry of water or foreign matter.SOLUTION: A one-way clutch 10 is assembled between a pulley 1 and a pulley hub 3 assembled in the pulley 1. A disk-like dust cover 20 large enough to cover the whole of at least an inner peripheral part of an outside end surface of the pulley 1 is fitted to the outside end surface of the pulley 1. The dust cover 20 includes an annular seal lip 21, which is configured to be elastically brought into contact with the outside end surface of the pulley 1, so as to completely seal an end part opening of an annular space formed between opposite parts of the pulley 1 and the pulley hub 3. Water or foreign matter is prevented from entering the one-way clutch 10 assembled in the annular space, through the opening of the annular space.

Description

  The present invention mainly relates to a pulley unit with a built-in clutch that is used by being mounted on a rotating shaft of an engine accessory such as an alternator using an engine as a drive source.

  In general, in an accessory drive device that transmits the rotation of the crankshaft of the engine to the rotation shaft of the engine accessory by a belt transmission device, when the engine is suddenly decelerated, a pulley attached to the rotation shaft of the engine accessory is also included. Try to decelerate suddenly.

  At this time, if the engine accessory is an alternator, the rotating shaft of the alternator has a large inertial force. Therefore, the pulley attached to the rotating shaft tries to keep rotating at a constant speed, and the pulley on the crankshaft and the alternator rotate. A large rotational speed difference is generated between the pulleys on the shaft, and the belt tension is increased and the belt is easily damaged.

  In addition, the crankshaft fluctuates in angular speed during one rotation due to intermittent in-cylinder combustion in the engine and the inertial force of a reciprocating piston. Slip occurs between the pulley and the belt, and the slip causes wear of the belt, resulting in a decrease in durability.

  In order to eliminate such an inconvenience, a pulley unit with a built-in clutch in which a one-way clutch is incorporated in a pulley provided on a rotating shaft of an engine accessory has been proposed.

  When the pulley unit with a built-in clutch is mounted on the rotating shaft of the engine accessory, the one-way clutch is disengaged and the pulley is freed when the rotating speed of the pulley is lower than the rotating speed of the rotating shaft of the engine accessory. Since it rotates, it is possible to prevent an increase in belt tension, to prevent slippage between the pulley and the belt, and to suppress a decrease in durability of the belt.

  However, in the pulley unit with a built-in clutch as described above, since it is attached to be exposed to the outside below the vehicle body, muddy water splashed up by the wheel enters the inside, or water enters the inside by running in a puddle. In addition, the function of the one-way clutch may be hindered.

  In order to prevent the occurrence of such inconvenience, in the pulley unit with a built-in clutch described in Patent Document 1, a shield cover is attached to the inner shaft body incorporated inside the outer ring body, and the outer ring body is attached by the shield cover. An annular space formed between the opposed portions of the inner shaft body is covered, and water and foreign matter are prevented from entering the inside of the one-way clutch incorporated in the annular space.

Japanese Patent Laid-Open No. 2002-21982

  By the way, in the conventional pulley unit with a built-in clutch, the shield cover attached to the inner shaft body is configured to form a non-contact sealing portion consisting of a minute gap with the outer peripheral surface of the outer ring body. The annular space cannot be completely sealed, and if the vehicle is immersed in a puddle during running in a puddle, water can enter the annular space from a minute gap, which can impede the functionality of the one-way clutch. There is sex.

  An object of the present invention is to provide a pulley unit with a built-in clutch that can reliably prevent water and foreign matter from entering.

  In order to solve the above problems, in the present invention, a one-way clutch is incorporated between a pulley and a pulley hub incorporated inside the pulley, and transmission and interruption of rotational torque between the pulley and the pulley hub are performed. In the pulley unit with a built-in clutch, a disc-shaped dust cover having a size capable of covering at least the entire inner peripheral portion of the outer end face in the assembled state of the pulley is attached to the pulley, and the dust cover is attached to the dust cover. A configuration is adopted in which an annular seal lip is provided in elastic contact with the outer end face of the pulley.

  As described above, a disc-shaped dust cover that covers at least the entire inner peripheral portion of the outer end face of the pulley is attached to the pulley, and an annular seal lip that elastically contacts the outer end face of the pulley is provided on the dust cover. By this, the annular space formed between the pulley and the pulley hub can be completely sealed. Therefore, it is possible to reliably prevent water and foreign matter from entering the inside of the one-way clutch incorporated in the annular space.

  Here, if a plurality of seal lips having different diameters are provided on the dust cover, the gap between the dust cover and the facing portion of the pulley can be more reliably sealed.

  Also, if the seal lip has a taper shape that extends outward toward the tip, when water enters the inside from the outer periphery between the opposed portions of the pulley and the dust cover, the seal lip is outside the pulley by the pressure of the water. It will be pressed more strongly by the side surface, and water intrusion can be more effectively prevented.

When attaching the dust cover, the following attachment means a to c can be employed.
Mounting means a: An annular groove is formed on the outer end surface of the pulley, an annular engagement groove is provided on the outer peripheral surface of the closed end portion of the annular groove, and the dust cover has a flange on the formation surface of the seal lip. An engagement plate is provided, the engagement plate is inserted into the annular groove, and a flange portion at the tip is engaged with the engagement groove.
Mounting means b: An annular groove is formed on the outer end face of the pulley, an annular engagement groove is provided on the outer peripheral surface of the closed end of the annular groove, and a flange inserted into the annular groove is provided on the outer peripheral part of the dust cover. An outward bent piece formed at the tip of the flange is engaged with the engagement groove.
Attachment means c; a cylindrical portion is formed on the surface of the dust cover where the seal lip is formed, and the cylindrical portion is press-fitted into the inner diameter surface of the pulley.

  In the adoption of the attachment means a, the engagement plate may be discontinuous in the circumferential direction, or may be an annular one that is continuous in the circumferential direction. When the engagement plate is annular, since both the engagement plate and the seal lip can seal between the facing portions of the pulley and the dust cover, it is possible to more effectively prevent water and foreign matter from entering.

  In the present invention, as described above, the disc-shaped dust cover is attached to the pulley, covers at least the entire inner peripheral portion of the outer end face of the pulley, and the annular cover that elastically contacts the dust cover with the outer end face of the pulley. By providing the seal lip, the annular space formed between the pulley and the pulley hub can be completely sealed with the dust cover, and water and foreign matter can enter the one-way clutch incorporated in the annular space. Can be reliably prevented.

  In addition, the dust cover rotates together with the pulley in a non-contact state with respect to the pulley hub when the rotation transmission from the pulley to the pulley hub is interrupted by the disengagement of the one-way clutch. Effective use of energy can be achieved.

A longitudinal front view showing an embodiment of a pulley unit with built-in clutch according to the present invention Sectional view along the line II-II in FIG. Sectional view showing enlarged dust cover attachment Sectional view showing another example of dust cover installation Sectional drawing which shows the further another example of attachment of a dust cover

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the pulley 1 has double rows of V-grooves 2 on the outer peripheral surface, and a pulley hub 3 is incorporated inside the pulley 1.

  On the outer periphery of the pulley hub 3, a large-diameter cam ring portion 4 and a pair of cylindrical bearing surfaces 5 are formed on both axial sides of the cam ring portion 4, and each of the pair of bearing surfaces 5 and the inner diameter surface of the pulley 1 are formed. A bearing 6 is incorporated between them.

  The bearing 6 is provided with a single seal, and the seal 6a is assembled so as to be arranged on the outer side. The pulley 1 and the pulley hub 3 are relatively rotatable by the bearing 6.

  A one-way clutch 10 is incorporated between the pair of bearings 6. As shown in FIGS. 1 and 2, the one-way clutch 10 has a cylindrical inner surface 12 formed on a steel outer ring 11 press-fitted into an inner diameter surface of a pulley 1, and an outer periphery of a cam ring portion 4 formed on a pulley hub 3. A plurality of cam surfaces 13 forming a wedge space between the inner surface 12 and the cylindrical inner surface 12 are provided at intervals in the circumferential direction, and a plurality of cages 14 are provided between the opposing portions of the outer ring 11 and the pulley hub 3. A pocket 15 is formed so as to face the cam surface 13, and an engaging member 16 made of a roller and a spring 17 for urging the engaging member 16 toward a narrow portion of the wedge space are incorporated in the pocket 15. It is said.

  As shown in FIG. 1, the pulley 1 is provided with a dust cover 20 made of a synthetic resin molded product on an outer end surface in an assembled state with respect to a rotation shaft of an automobile auxiliary machine. The dust cover 20 has a disk shape, and the outer diameter of the dust cover 20 is large enough to cover the entire inner peripheral portion of the outer end of the pulley 1.

  The dust cover 20 is attached to the pulley 1. A plurality of elastic seal lips 21 having different diameters are formed concentrically on the surface facing the pulley 1, and the tip of each seal lip 21 is in elastic contact with the outer end surface of the pulley 1 so that the pulley 1 and dust The space between the facing portions of the cover 20 is sealed.

  Further, as shown in FIG. 3, each of the seal lips 21 has a tapered shape that extends outward toward the tip.

  When attaching the dust cover 20, here, an annular groove 22 is formed on the outer end surface of the pulley 1, an annular engagement groove 23 is provided on the outer peripheral surface of the closed end of the annular groove 22, and the dust cover 20 is sealed. An engagement plate 24 is formed on the surface on which the lip 21 is formed, and a flange portion 25 facing radially outward is provided at the distal end portion of the engagement plate 24. The engagement plate 24 is inserted into the annular groove 22, and the flange portion 25 is engaged. The dust cover 20 is engaged with the mating groove 23 so that the dust cover 20 is not separated in the axial direction with respect to the pulley 1.

  Here, in the embodiment, the engagement plate 24 has an annular shape that is continuous in the circumferential direction, but may be a piece that is discontinuous in the circumferential direction.

  The pulley unit with a built-in clutch shown in the embodiment has the above-described structure, and when driving an alternator as an engine accessory, the pulley hub 3 is attached to the rotating shaft of the alternator. In this case, it is assumed that the dust cover 20 is assembled outside.

  In the state of use as described above, when the rotation of the crankshaft is transmitted to the pulley 1 and the outer ring 11 integrated with the pulley 1 rotates in one direction indicated by the arrow in FIG. 2, the engagement element 16 of the one-way clutch 10 is moved to the outer ring 11. Of the inner ring 12 and the cam surface 13 of the pulley hub 3, and the rotation of the outer ring 11 is transmitted to the pulley hub 3 through the engagement element 16. The pulley hub 3 rotates in the same direction as the pulley 1, and the rotating shaft of the alternator Rotate.

  When the rotational speed of the pulley hub 3 that rotates integrally with the rotating shaft of the alternator exceeds the rotational speed of the pulley 1 in a state where the rotational torque is transmitted from the pulley 1 to the rotating shaft of the alternator due to rapid engine deceleration or the like, The engagement with the cam surface 13 is released, and the rotation of the pulley 1 is not transmitted to the pulley hub 3 and the pulley 1 rotates freely.

  The pulley unit with built-in clutch attached to the rotating shaft of the alternator is exposed to the outside and is not protected by the cover, and it is covered with water such as muddy water splashed by the wheels, or it runs in a puddle. It is under severe usage conditions where it is immersed in accumulated water.

  At this time, in the pulley unit with a built-in clutch according to the embodiment, the dust cover 20 is attached to the outer end surface of the pulley 1, and the seal lip 21 provided on the dust cover 20 is in elastic contact with the outer end surface of the pulley 1. In addition, since the annular space formed between the opposed portions of the pulley 1 and the pulley hub 3 is completely sealed by the dust cover 20, water and foreign matter do not enter the annular space.

  For this reason, there is no inconvenience that the function of the one-way clutch 10 incorporated in the annular space is deteriorated due to intrusion of water or foreign matter, and the clutch built-in pulley unit maintains good functionality over a long period of time. .

  In FIG. 3, an engagement plate 24 is provided on the dust cover 20, a flange 25 is provided at the tip of the engagement plate 24, and an engagement groove 23 is formed at the closed end of the annular groove 22 formed on the outer end surface of the pulley 1. Although the dust cover 20 is attached by engaging the flange 25 with the engaging groove 23, the means for attaching the dust cover 20 is not limited to this.

  4 and 5 show another example of the attaching means for the dust cover 20. In the attaching means shown in FIG. 4, an annular groove 22 is formed on the outer end surface of the pulley 1, and an annular engaging groove 26 having a semicircular cross section is provided on the outer peripheral surface of the closed end portion of the annular groove 22. A flange 27 to be inserted into the annular groove 22 is provided on the outer peripheral portion of the outer peripheral portion 20, and an outward U-shaped bent piece 28 formed at the distal end portion of the flange 27 is engaged with the engagement groove 26 so as to cover the dust cover. There are 20 attachments.

  In the attaching means shown in FIG. 5, a cylindrical portion 29 is formed on the inner portion of the seal lip 21 formed on the dust cover 20, and the cylindrical portion 29 is press-fitted into the inner diameter surface of the pulley 1 to attach the dust cover 20. Yes. At this time, in order to ensure the retaining of the cylindrical portion 29, the engaging protrusion 30 is provided on the outer periphery of the tip of the cylindrical portion 29, and the engaging protrusion 30 is formed on the inner diameter surface of the pulley 1. The engaging groove 31 is engaged.

  4 and 5, the dust cover 20 can be attached stably and reliably, and the dust cover 20 is attached by pushing it in the axial direction from the state facing the outer end face of the pulley 1. Since it can be in a state, the dust cover 20 can be easily attached.

DESCRIPTION OF SYMBOLS 1 Pulley 3 Pulley hub 10 One-way clutch 20 Dust cover 21 Seal lip 22 Annular groove 23 Engagement groove 24 Engagement plate 25 Gutter part 26 Engagement groove 27 Flange 28 Folding piece 29 Cylindrical part

Claims (7)

In a pulley unit with a built-in clutch that incorporates a one-way clutch between a pulley and a pulley hub built in the pulley, and transmits and shuts off rotational torque between the pulley and the pulley hub.
A disc-shaped dust cover having a size that can cover at least the entire inner peripheral portion of the outer end surface in the assembled state of the pulley is attached to the pulley, and the outer end surface of the pulley is elastically attached to the dust cover. A pulley unit with a built-in clutch, characterized in that an annular sealing lip is provided.   The pulley unit with a built-in clutch according to claim 1, wherein a plurality of the seal lips are provided, and the diameters of the respective seal lips are different.   The pulley unit with a built-in clutch according to claim 1 or 2, wherein the seal lip is tapered so as to expand outward toward the tip.   An annular groove is formed on the outer periphery of the contact portion with which the seal lip of the pulley outer end surface contacts, an annular engagement groove is provided on the outer peripheral surface of the closed end of the annular groove, and the dust cover has a seal lip. 4. The dust cover is attached by providing an engagement plate having a flange portion on the forming surface, inserting the engagement plate into the annular groove, and engaging the flange portion on the distal end with the engagement groove. The pulley unit with a built-in clutch according to any one of the above.   The pulley unit with a built-in clutch according to claim 4, wherein the engagement plate has an annular shape that is continuous in a circumferential direction.   An annular groove is formed on the outer periphery of the contact portion with which the seal lip of the pulley outer end surface contacts, an annular engagement groove is provided on the outer peripheral surface of the closed end of the annular groove, and the outer periphery of the dust cover 4. A dust cover is mounted by providing a flange to be inserted into the annular groove, and engaging an outwardly bent piece formed at the tip of the flange with the engagement groove. Pulley unit with built-in clutch described in 2.   The cylindrical part is formed in the surface in which the seal lip of the dust cover was formed, and the cylindrical part was press-fitted into the inner diameter surface of the pulley, and the dust cover was attached. Pulley unit with built-in clutch.

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