JP6777464B2 - Pulley unit - Google Patents

Description

The present invention relates to a pulley unit including a pulley used for a belt transmission device such as a timing belt or an auxiliary belt of an automobile engine and a rolling bearing that rotatably supports the pulley.

Normally, in a belt transmission device that drives an automobile auxiliary machine such as an alternator or a compressor, the idler pulley guides the movement of the belt, or the hydraulic auto tensioner presses the tension pulley against the belt to absorb the tension fluctuation of the belt. I am doing it. The idler pulley and tension pulley are rotatably supported by rolling bearings that are incorporated into the inner diameter side of the boss portion and unitized.

By the way, when a pulley unit having a rolling bearing is incorporated in a belt transmission device such as a timing belt or an auxiliary belt of an automobile engine, foreign matter such as muddy water coming from the outside of the rolling bearing is inside the bearing. It is easy to get in, and the invasion of foreign matter may impair the original function of the rolling bearing at an early stage.

In order to improve the water resistance of the pulley unit, a rolling bearing with a seal is adopted.
The basic sealing structure used for rolling bearings with a seal is, for example, the lip provided on the inner circumference of a ring-shaped seal is elastically brought into contact with the outer diameter surface of the inner ring, and the tightening allowance allows water to enter from the outside. Although it is a structure to prevent it, if the above tightening allowance is made too large, the rotational torque of the bearing will be increased, so the tightening allowance cannot be made sufficiently large, and as a result, water will completely enter the bearing. It could not be prevented.

Further, for example, as described in Patent Documents 1 and 2, there is also one in which the water resistance of the bearing device for a pulley is improved by providing slingers on both sides of a bearing that rotatably supports the pulley body.
However, since the outer peripheral portion of the slinger is in a non-contact state with the side surface of the outer ring that rotates with the pulley body and has a gap, external water or foreign matter may infiltrate through this gap and seal the slinger. It is necessary to provide a contact type bearing seal that contacts the lip.

In the bearing sealing device with a slinger described in Patent Document 2, the main seal lip is elastically brought into contact with the axial end of the step portion formed at the end of the inner ring, and the secondary seal lip is also used in combination with the double seal lip. The seal structure increases the "tightening allowance" to improve water resistance.

Further, to explain with reference to FIGS. 7 and 3 (a), in the pulley unit described in Patent Document 3, by arranging the slinger 7 on the outside of the elastic sealing member 8, muddy water or the like is directly applied to the lip. The elastic seal member 8 is provided with an axial lip 8b and is brought into contact with the slinger 7, and when a strong pressure is applied from the outside by washing water or the like, the axial lip 8b is pressed by the slinger to cause water or the like. It has a structure to prevent the infiltration of water.

Further, as shown in FIG. 7, the flange 21 of the pulley shaft 20 and the inner ring 6 of the rolling bearing sandwich the inner peripheral portion of the annular dust cover 22 from both sides, and the dust cover 22 sandwiches one side surface of the rolling bearing and the rolling bearing. The outer circumference of one end of the boss portion 3 is covered.

JP-A-2009-216138 JP-A-2009-216139 Japanese Unexamined Patent Publication No. 2015-194172

However, as shown in FIGS. 7 and 3 (b), the rolling bearing for a pulley having the above-mentioned sealing structure is used for outer ring rotation via a belt, and the rolling bearing rotates, and a strong centrifugal force is applied to the axial lip 8b. When the action is applied, the axial lip 8b is deformed so as to be pulled toward the outer ring side, and there is a problem that the "tightening allowance" of the seal, that is, the contact area is reduced and the water resistance is lowered.

Further, in order to prevent centrifugal force from acting on the axial lip 8b as much as possible, it is preferable to seal the axial lip 8b at a position as close as possible to the cylindrical portion 7a of the slinger 7.
However, even if such measures are taken, as shown in FIG. 8, angular runout may occur in the pulley bearing, and the amount of angular runout is larger on the outer ring side, and the distance between the inner and outer rings L ₁ And L ₂ also change according to the amount of angular runout (θ), and it is quite difficult to set the tightening allowance of the side lip in advance so as to correspond to these.

Further, since the conventional dust cover 22 (see FIG. 7) is attached to the inner ring 6 of the bearing, the bearing space formed between the rotating outer ring 5 and the fixed inner ring 6 cannot be sealed. It was.

Therefore, the subject of the present invention is to solve the above-mentioned problems in the prior art, and in a pulley unit having a contact-type bearing seal that brings the lip into contact with the slinger, a tightening allowance due to centrifugal force of the rolling bearing used for outer ring rotation. The pulley unit should be able to reliably prevent the ingress of muddy water and other foreign matter in the harsh usage environment of automobiles.

In order to solve the above problems, in the present invention, a pulley having a boss portion inside the belt guide wheel and a bearing for rotating an outer ring incorporated inside the boss portion are provided. Each of the openings at both ends of the bearing space formed between the outer ring and the inner ring is sealed with a sealing member, and the sealing member is attached to the outer end of the cylindrical portion fixed to the outer diameter surface end of the inner ring. The elastic sealing member has an L-shaped slinger provided with an outer ring, and an elastic sealing member having an outer peripheral portion supported at both ends on the inner diameter surface of the outer ring and an inwardly inclined portion provided on the inner peripheral portion. In a pulley unit in which one or more lips are provided on a surface facing the slinger and one or more of the lips are elastically contacted with the slinger, a dust cover for liquid-tightly covering the bearing end surface is provided integrally with the pulley. It was a bearing unit.

The pulley unit of the present invention configured as described above has a contact-type bearing seal that brings the lip into contact with the slinger, but by providing a dust cover that covers the end face of the bearing liquid-tightly with the pulley. , The outer ring of the bearing is covered with a dust cover to make the bearing end face liquid-tight against liquids such as water, mud, and dust that may exist in the usage environment of the pulley unit or particulate foreign substances such as dust. Foreign matter does not enter the bearing space formed between the inner ring and the inner ring.

Since the dust cover is provided integrally with the pulley and covers the end face of the bearing in a liquid-tight manner, it is not necessary to contact the inner ring or slinger of the bearing to ensure the sealing property, and therefore the bearing is contacted with the bearing. Does not increase torque. Further, for the same reason as described above, the dust cover does not deteriorate in sealing performance even if the amount of angular runout (the amount of inclination in the pulley axial direction) is large.

The pulley unit having a structure in which one or more lips are provided on the surface of the elastic sealing member facing the slinger and one or more of the lips are elastically brought into contact with the slinger is "reduced in water resistance due to centrifugal force" by the dust cover. The problem of "difficulty in setting the tightening allowance of the side lip corresponding to the amount of angular runout" has been solved, the tightening allowance is reduced due to the centrifugal force of the rolling bearing used for outer ring rotation, and muddy water in the harsh usage environment of automobiles, etc. It is a pulley unit that can reliably prevent the intrusion of foreign matter.

Further, the pulley unit of the present invention includes, for example, an axial lip in which the one or more lips extend outward from the outer surface of the elastic sealing member and the tip end elastically contacts the outward flange of the slinger. Even if the device has a structure in which the tip portion extends radially from the inclined portion and has a non-contact radial lip at a minute interval with respect to the outer diameter surface of the cylindrical portion of the slinger, the above-mentioned "centrifugal force" is provided by the dust cover. It is possible to solve the problems of "decrease in water resistance due to" and "difficulty in setting the tightening allowance of the side lip corresponding to the amount of angular runout".

Since the lip rotates in contact with the slinger, the elastic sealing member is preferably formed of a rubber having excellent flexibility and abrasion resistance. As such a rubber, an elastic sealing member made of nitrile rubber, acrylic rubber or fluororubber. Can be mentioned.

Further, it is preferable that the axial lip exhibits stable water resistance regardless of whether the pulley is used or not, and for that purpose, the tip of the axial lip is oriented so as to intersect the front and back surfaces in the radial direction. It has the above grooves, and these grooves are in a form (width, depth) that can be closed by elastic deformation due to pressure contact with the slinger.

That is, in the state where the axial lip is in pressure contact with the slinger and elastically deformed when the pulley is not used, the groove is opposed to the groove in which the groove formed at the tip intersects in the radial direction due to the pressure applied from the radial direction of the shaft. The groove walls are elastically deformed so as to approach each other, and the grooves are closed to prevent foreign matter such as water from entering from the outside.

In addition, when the pulley is in a rotating state, the centrifugal force acting on the axial lip weakens the pressure contact force with the slinger, so even if there is foreign matter such as water that has entered the space inside the rolling bearing, the groove will open. They are ejected from the ditch to the outside by centrifugal force.

Further, since an inertial force acts on foreign matter such as droplets and dust in the rotation direction when the pulley rotates, the groove is radial from the axial center of the rotating bearing so that the foreign matter is discharged from the groove as soon as possible. Alternatively, the grooves are preferably arranged in a radial curve.

As an application of the pulley unit in which such an action is effective, the pulley unit is a pulley unit for an automobile engine, and in this case, the bearing end face provided with the dust cover is in the axial direction on the opposite side of the engine. It is effective and preferable that it is an end face.

The present invention exists in the usage environment of the pulley unit by providing a dust cover that covers the end face of the bearing liquid-tightly with the pulley in the pulley unit having a contact type bearing seal that brings the lip into contact with the slinger. Liquids such as water, mud, dust and other particulate foreign matter such as dust do not enter the bearing space, and the dust cover does not need to be in contact with the bearing and does not increase the bearing torque, and centrifugal force. Since there is no deterioration in sealing performance due to, there is an advantage that the tightening margin due to the centrifugal force of the rolling bearing used for outer ring rotation is reduced, and the pulley unit can reliably prevent the ingress of muddy water and other foreign substances in the harsh usage environment of automobiles. is there.

Sectional drawing of the pulley unit of embodiment Perspective view of the pulley unit of the embodiment (a) Enlarged sectional view of the main part of FIG. 1 explaining the seal member when the pulley is not used, and (b) Enlarged sectional view of the main part of FIG. 1 explaining the seal member when the pulley is used. Enlarged sectional view of a main part for explaining the seal member in the second embodiment. Top view of the seal member according to the third embodiment Top view showing a part of FIG. 5 enlarged Sectional view of the conventional pulley unit Cross-sectional view of a pulley bearing for explaining the angle runout phenomenon

Embodiments of the present invention will be described below with reference to the accompanying drawings.
As shown in FIGS. 1 to 3, in the first embodiment, a pulley in which a boss portion 3 is provided inside the belt guide wheel 2 of the pulley 1 and a rolling bearing 4 for rotating an outer ring is incorporated inside the boss portion 3. It is a unit, and each of the openings at both ends of the bearing space formed between the outer ring 5 and the inner ring 6 of the rolling bearing 4 is sealed by a sealing member.
In this seal member, the cylindrical portion 7a of the slinger 7 having an L-shaped cross section and the outer end portion of the cylindrical portion 7a provided with the outward flange 7b is press-fitted and fixed to the outer diameter surface end portion of the inner ring 6 to fix the inner peripheral portion. An annular elastic sealing member 8 provided with an inwardly inclined portion 8a is provided on both ends of the inner diameter surface of the outer ring 5 to support outer peripheral portions, and the elastic sealing member 8 is elastically provided on the surface facing the slinger 7. An axial lip 8b extending outward from the outer surface of the sealing member 8 and having an elastic contact with the outward flange 7b of the slinger 7 is provided, and the tip portion extends radially from the inclined portion 8a and has a tip portion of the slinger 7. A radial lip 8c that makes elastic contact with the outer diameter surface of the cylindrical portion 7a is provided, and a dust cover 9 that tightly covers the end surface of the bearing is provided integrally with the pulley 1.

The pulley 1 has a belt guide ring 2 on the outer diameter portion, an annular flange 1a is formed on the inner diameter surface of the belt guide ring 2, and a boss portion 3 is provided on the inner diameter portion of the annular flange 1a. It is made of a product, and an inward flange 3a is provided at one end of the boss portion 3.

As the belt guide wheel 2, the one for flat belt guide having an outer diameter surface formed of a cylindrical surface is shown here, but the one for V belt guide in which a plurality of V grooves are formed on the outer diameter surface may be used. ..

The rolling bearing 4 is composed of a ball bearing having a ball 10 as a rolling element incorporated between an outer ring 5, an inner ring 6, and both wheels 5 and 6, and a sealing member is incorporated on the outside of the balls 10 in each row to seal the rolling bearing 4. The openings at both ends of the bearing space formed between the facing surfaces of the outer ring 5 and the inner ring 6 by the member are sealed.
Although the case of a single-row ball bearing is shown as the ball bearing, a double-row ball bearing or a plurality of single-row ball bearings, for example, two rows may be used as long as there is no problem. ..

As shown in FIG. 3, the sealing member includes a slinger 7 mounted on the outer diameter surface end portion of the inner ring 6 and an elastic sealing member 8 provided inside the slinger 7.
The slinger 7 is made of a press-molded steel plate having an outward flange 7b provided at one end of the cylindrical portion 7a, and is fixed in a state where the cylindrical portion 7a is press-fitted into the outer diameter surface end portion of the inner ring 6.

The elastic sealing member 8 is annular and is also reinforced with an annular core metal 11. A fitting portion 8d is provided on the outer peripheral portion of the elastic sealing member 8 so as to cover the cylindrical portion 11a formed on the outer periphery of the core metal 11, and the fitting portion 8d is formed on the inner diameter surface end portion of the outer ring 5. The outer peripheral portion is supported by the outer ring 5 by being press-fitted into the seal mounting groove 5a.

Further, an inwardly inclined portion 8a is formed on the inner peripheral portion of the elastic seal member 8. An inclined axial lip 8b facing diagonally outward is provided on the outer surface of the elastic seal member 8, and the tip end portion of the axial lip 8b elastically contacts the inner surface of the outward flange 7b of the slinger 7 to elastically seal. The facing portion between the member 8 and the outward flange 7b is sealed.

On the other hand, a pair of radial lips 8c and 8c are provided on the inner circumference of the inclined portion 8a of the elastic seal member 8. Each of the pair of radial lips 8c and 8c is inclined inward toward the outside, and the tip portion thereof elastically contacts the outer diameter surface of the cylindrical portion 7a of the slinger 7 between the cylindrical portion 7a and the inclined portion 8a. Is sealed.

Further, each of the axial lip 8b and the radial lips 8c and 8c elastically contacts the inner side surface of the outward flange 7b of the slinger 7 and the outer diameter surface of the cylindrical portion 7a to seal between the facing portions, thereby providing flexibility and flexibility. It is preferably formed of rubber having excellent wear resistance. Examples of such rubber include nitrile rubber, acrylic rubber, and fluororubber.

As shown in FIG. 1, when the rolling bearing 4 is press-fitted into the inner diameter surface of the boss portion 3 of the pulley 1, the rolling bearing 4 is positioned in the axial direction by the above-mentioned inward flange 3a.
The elastic sealing member 8 whose outer peripheral portion is supported on the inner diameter surface of the outer ring 5 has the axial lip 8b and the pair of radial lips 8c and 8c respectively on the outer diameter surface of the outward flange 7b of the slinger 7 and the cylindrical portion 7a. The gap between the slinger 7 and the elastic sealing member 8 is liquid-tightly sealed by elastic contact.

Further, as shown in FIGS. 1 and 2, in the pulley unit of the embodiment, a disk-shaped dust cover 9 is provided so as to cover the end surface of the rolling bearing 4 in a liquid-tight manner, and a portion of the cylindrical rim 9a thereof is covered with the pulley 1. These are integrated by press-fitting into the inside of one end of the belt guide wheel 2.

The dust cover 9 is preferably made of metal or synthetic resin, but may be a composite material as long as it does not allow dust such as water, mud or dirt, or at least a liquid such as water to pass through. Fiber reinforced plastics such as carbon fiber and glass fiber, rubber, and other well-known liquid-tight materials can be used.

Such integration of the dust cover 9 and the pulley 1 is shown in an integrated state by crimping or press-fitting, but it is also integrated by a well-known fixing means such as adhesive, screw connection, or snap connection. It may be.
Further, the attachment position of the dust cover 9 to the pulley 1 does not have to be not only inside one end of the belt guide wheel 2 of the pulley 1, but is attached to the annular flange 1a and the boss 3 by the same fixing means as described above. Can be done.

By providing the dust cover 9 integrally with the pulley 1 in this way, the end surface of the rolling bearing 4 is covered with liquid tightness, and foreign matter does not enter the bearing space formed between the outer ring 5 and the inner ring 6. Therefore, foreign matter from the outside does not directly collide with the axial lips 8b, radial lips 8c, and 8c of the elastic sealing member 8, and the elastic sealing member 8 is not damaged by the collision of such foreign matter.

Further, when the engine room is washed with high-pressure washing water, the liquidtightness of the dust cover 9 makes it relatively high speed for each of the plurality of lips 8b, 8c, 8c depending on the high-pressure washing water and the speed of the automobile. Since no liquid such as scattered mud or dust or droplets such as dust or other particulate foreign matter is directly sprayed, the droplets or water are caused by the elastic contact of each of the plurality of lips 8b, 8c, 8c. It is possible to surely prevent such things from entering the inside of the bearing.

Next, in the second embodiment of the present invention shown in FIG. 4, the radial seal of the elastic seal member 12 having substantially the same shape as the first embodiment does not utilize the elastic contact property of the lip, but is elastic. The inner diameter surface of the inwardly inclined portion 12a of the seal member 12 is projected toward the inner ring 6, and the tip portion 12c thereof is small enough to prevent the flow of grease with respect to the outer diameter surface of the cylindrical portion 7a of the slinger 7. It is opposed to each other through the gap d.

If it is such a minute gap d, the particles are scattered in advance by the dust cover 9 (see FIG. 1) and the axial lip 12b installed outside the gap d at a relatively high speed depending on the high-pressure washing water or the speed of the automobile. Since the ingress of foreign matter is prevented and it is not directly sprayed, it is sufficient if there is a function that can prevent leakage due to the flow of grease held inside the rolling bearing, and it is not pressurized such as water droplets. The ingress of water etc. is also prevented.

Next, in the third embodiment shown in FIGS. 5 and 6, the form of the axial lip 8b of the annular elastic sealing member 8 (see FIG. 1) in the first embodiment is changed, and the pulleys are configured in exactly the same manner except for the above. It is a unit.
The axial lip 13b in the elastic sealing member 13 of the third embodiment has a plurality of grooves 13a formed at the tip in a direction that intersects the front and back surfaces in the radial direction, as if the tip thereof was cut out. Grooves 13a along the radial curve extending from the axis of the bearing are formed at equal intervals in the circumferential direction, and the size (groove width and depth) of the grooves 13a is the same as that of the slinger 7 (see FIG. 3 (a)). It is set so that it can be closed by elastic deformation due to pressure welding.

The groove 13a is in a state in which the axial lip 13b is elastically deformed by being pressed against the slinger 7 when the pulley is not in use and is in a non-rotating state (see FIG. 3A), and is formed at the tip edge at this time. Since the wall surfaces of the grooves 13a facing each other are in contact with each other due to the pressure applied from the radial direction of the shaft, the flow path of the groove 13a is blocked and foreign matter such as water can be prevented from entering from the outside of the bearing.

Further, in the rotating use state of the pulley (see FIG. 3B), the pressure contact force with respect to the slinger 7 is weakened by the centrifugal force acting on the axial lip 13b, so that the flow path of the groove 13a opens and intersects in the radial direction. Even if there is a foreign substance such as water that penetrates in the bearing space and has entered the bearing space, it can be discharged from the groove 13a to the outside of the bearing outside the elastic sealing member 13 by centrifugal force.
The illustrated groove 13a follows a radiation curve extending from the axial center of the bearing, and is shaped so that foreign matter can be smoothly discharged from the groove 13a by the above action.
The groove 13a extending in a radial curve from the axial center of the bearing can be arranged so that the groove end near the axial center of the rolling bearing is tilted in the direction of rotation of the outer ring 5, so that foreign matter such as water subjected to centrifugal force can be removed as quickly as possible. It is preferable to discharge to.

All of the pulley units of the above-described embodiments can solve the problems in the prior art such as "decrease in water resistance due to centrifugal force" and "difficulty in setting the tightening allowance of the side lip corresponding to the amount of angular runout". This is a pulley unit that can reliably prevent the tightening allowance due to the centrifugal force of the rolling bearing used for outer ring rotation and the intrusion of muddy water and other foreign substances in the harsh usage environment of automobiles.

1 Pulley 1a Circular flange 2 Belt guide ring 3 Boss part 3a Inward flange 4 Rolling bearing 5 Outer ring 5a Seal mounting groove 6 Inner ring 7 Slinger 7a Cylindrical part 7b Outer flange 8, 12, 13 Elastic seal member 8a, 12a Inclined part 8b , 12b, 13b Axial lip 8c, 13c Radial lip 12c Tip part 8d, 13d Fitting part 13a Groove 9, 22 Dust cover 9a Rim 10 Ball 11 Core metal 11a Cylindrical part 20 Pulley shaft 21 Flange 22 Dust cover d Gap

Claims (5)

A pulley having a boss portion inside the belt guide ring and a rolling bearing for rotating an outer ring incorporated inside the boss portion, and a bearing space formed between the outer ring and the inner ring of the rolling bearing. Each of the openings at both ends is sealed with a sealing member, and the sealing member is a slinger having an L-shaped cross section provided with an outward flange at the outer end of a cylindrical portion fixed to the outer diameter surface end of the inner ring. An elastic sealing member having an outer peripheral portion supported on both ends of the inner diameter surface of the outer ring and an inwardly inclined portion provided on the inner peripheral portion, and one or more lips on the surface of the elastic sealing member facing the slinger. In a pulley unit, which is an axial lip in which one or more of the lips extend outward from the outer surface of the elastic sealing member and the tip portion elastically contacts the outward flange of the slinger.
A dust cover that covers the outside of the bearing end surface in a liquid-tight manner is provided integrally with the pulley, and the axial lip has one or more grooves at its tip in a direction that intersects the front and back surfaces in the radial direction. The pulley is characterized in that the groove can be closed by elastic deformation due to pressure contact with the slinger, and in the rotating state of the pulley, the pressure contact force with respect to the slinger is weakened by the centrifugal force acting on the axial lip and the groove is opened. unit. The one or more lip, before and Kia Kisharurippu, and non-contact of the radial lip at a small distance from the outer surface of the cylindrical portion of the tip portion extending the inner ring direction from said inclined portion the slinger The pulley unit according to claim 1. The pulley unit according to claim 1 or 2, wherein the elastic sealing member is an elastic sealing member made of nitrile rubber, acrylic rubber or fluororubber. The pulley unit according to any one of claims 1 to 3, wherein the grooves are a plurality of grooves arranged radially or in a radial curve from the axial center of the bearing. The pulley unit according to any one of claims 1 to 4 , wherein the pulley unit is a pulley unit for an automobile engine, and the bearing end surface provided with the dust cover is an axial end surface on the opposite side of the engine.

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