JP6755156B2 - Rolling bearing with seal for pulley unit - Google Patents

Description

The present invention relates to a rolling bearing with a seal for a pulley unit that can prevent foreign matter such as water, mud, and dust from entering the inside of the rolling bearing.

In general, there is a rolling bearing incorporated in a belt transmission device near the engine of an automobile as an example of a case where the rolling bearing is easily contacted with foreign matter such as water, mud, dust, etc. in the state of use of the rolling bearing. Foreign matter such as water or muddy water easily enters the inside of the bearing from the outside, and the infiltration of the foreign matter may impair the original function of the rolling bearing at an early stage.

In a belt transmission device that drives auxiliary equipment such as an alternator or compressor near the engine of an automobile, the idler pulley guides the movement of the belt, or the hydraulic auto tensioner presses the tension pulley against the belt to change the tension of the belt. Absorb. Such an idler pulley or tension pulley is supported by a rolling bearing unitized with the pulley by being incorporated on the inner diameter side of the boss portion.

In order to improve the water resistance of the rolling bearing for the pulley unit, a rolling bearing with a seal is adopted.
The basic sealing structure used for rolling bearings with seals for pulley units is, for example, to elastically contact the lip provided on the inner circumference of the ring-shaped seal with the groove edge of the annular groove on the outer diameter of the inner ring and tighten it. It is a structure that prevents water from entering from the outside by the allowance, but if the above tightening allowance is made too large, the rotational torque of the bearing will increase, so the tightening allowance cannot be increased sufficiently, and as a result, the bearing It was not possible to completely prevent the ingress of water into the interior.

For example, as described in Patent Documents 1 and 2, some roll bearings are provided with slingers on both sides to improve water resistance. However, since the outer peripheral portion of the slinger is in a non-contact state with respect to the side surface of the rotating outer ring and has a gap, external water or foreign matter may infiltrate through this gap, and the seal lip comes into contact with the slinger. It is necessary to provide a contact-type bearing seal that allows the contact.
Further, in recent years, automobiles are required to be manufactured assuming various usage conditions overseas, and in particular, the demand for water resistance on rough roads is increasing, and improvement in sealing performance is required.

In the rolling bearing with a seal 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 auxiliary seal lip is also used in combination with the double seal structure. The "tightening allowance" is increased to improve water resistance.

That is, the conventional rolling bearing shown in FIG. 7 has a structure in which the slinger 7 fixed to the inner ring 3 is arranged outside the elastic sealing member 20 fixed to the outer ring 2 so that muddy water or the like does not directly hit the lip. The elastic seal member 20 is provided with the side lip 21 and is brought into contact with the slinger 7. When a strong pressure such as washing water is applied from the outside, the side lip 21 is strongly pressed against the slinger 7 to prevent water or the like. It has a structure to prevent intrusion.

JP-A-2009-216138 JP-A-2009-216139

However, when the rolling bearing having the above-mentioned conventional sealing structure is used for outer ring rotation via a belt, when a strong centrifugal force acts on the side lip 21 in the direction indicated by the arrow in FIG. 7, the side lip 21 is used. 21 has a problem that it is elastically deformed so as to approach the outer ring 2 side (indicated by a chain line in the figure), the "tightening allowance" of the seal, that is, the contact area of the lip is reduced, and the water resistance is lowered.

Further, once foreign matter such as water has entered the inside of the side lip 21, it is difficult to discharge the foreign matter to the outside of the side lip 21 having an increased contact area.

Therefore, the subject of the present invention is to solve the above-mentioned problems in the prior art, and to deal with foreign matter such as water during non-rotation and low-speed rotation in a sealed rolling bearing having a contact-type bearing seal that brings the lip into contact with the slinger. In addition to having sufficient sealing properties, it is intended to prevent a decrease in water resistance when used in an outer ring rotation, and to always prevent the intrusion of muddy water and other foreign substances in the harsh usage environment of an automobile, for example. Further, in addition to the above effects, even if foreign matter such as water or muddy water enters the inside of the seal lip, the rolling bearing with a seal for the pulley unit can easily remove the foreign matter to the outside of the rolling bearing.

In order to solve the above problems, in the present invention, a sealing member for sealing each of the openings at both ends of the bearing space formed between the outer ring and the inner ring of the rolling bearing of the outer ring rotation is provided on the outer diameter surface end portion of the inner ring. A slinger having an outward flange provided at the outer end of the fixed cylindrical portion and having a substantially L-shaped cross section, and outer peripheral portions at both ends of the inner diameter surface of the outer ring, which are arranged axially inward from the outward flange of the slinger. Rolling with a seal for a pulley unit, which has an annular elastic seal member to which is fixed, and two or more annular lips are provided on the surface of the elastic seal member facing the slinger to make elastic contact with the slinger. In the bearing, a contact seal is provided between the inner surface of the bent portion in which the peripheral edge of the outward flange is bent inward and the outer surface of the annular lip arranged on the outermost side by centrifugal force due to the rotation of the outer ring of the rolling bearing. It was a rolling bearing with a seal for the pulley unit provided with a possible gap seal. As the gap seal, one that forms a labyrinth by having a ridge on the outer surface of the annular lip facing the inner surface of the bent portion may be adopted.

The rolling bearing with a seal for a pulley unit of the present invention configured as described above has an inner surface of a bent portion in which the peripheral edge of an outward flange is bent inward and an outer surface of an annular lip arranged on the outermost side. By providing a gap seal that can be contact-sealed by centrifugal force due to the rotation of the outer ring of the rolling bearing, the bent portion of the outward flange and the annular lip are provided when the rolling bearing is in a non-rotating state or a low-speed rotating state. The gap seal exerts a sealing function in a state where there is no frictional resistance through a small gap while keeping the non-contact state.
Further, when the gap seal has a ridge on the outer surface of the annular lip, the gap seal sufficiently exhibits the sealing property by labyrinth.

In other words, the gap seal, which is a form of non-contact seal, resists the passage of liquid foreign matter such as water outside the bearing due to the resistance of a small gap or passage when there is a possibility that liquid foreign matter such as water may enter the bearing space. It enhances and further blocks the passage of such liquid foreign matter.

Further, when the rolling bearing with a seal for the pulley unit of the present invention increases the rotation speed of the outer ring, an outward centrifugal force acts on the annular lip according to the rotation speed, and the outermost circle is arranged. The annular lip is elastically deformed outward in the axial direction by centrifugal force and elastically contacts the inner diameter surface of the peripheral edge of the outward flange of the slinger, so that the gap of the gap seal described above is closed and the rolling bearing. The openings at both ends of the bearing space formed between the outer ring and the inner ring of the bearing space are more completely sealed, and the water resistance is improved as compared with the state of the non-contact seal.
By being sealed in this way, water, muddy water, and other foreign substances are prevented from entering when the rolling bearing is used in a submerged state, for example, in a harsh usage environment of an automobile.

Of the above two or more annular lips, those arranged on the outermost side in the radial direction so that the contact sealing action is exerted as sharply as possible according to the rotational speed of the rolling bearing when centrifugal force acts in this way. However, it is preferable that the tip portion is thicker than the base portion and is an annular lip. With such a configuration, a large centrifugal force acts on the tip portion, which has a larger mass than the base portion, so that an elastic sealing action or a labyrinth or a gap sealing action is quickly exerted according to the rotation speed, and both ends of the bearing space are exhibited. The openings are always reliably sealed.

Further, by using a rolling bearing with a seal for a pulley unit in which the inner diameter surface of the peripheral edge of the outward flange is a tapered surface extending outward in the radial direction, the elastic sealing member is formed when the rotation of the rolling bearing is stopped. A downward flow path is formed between the slinger and the slinger so that the infiltrated water can naturally flow out, and the liquid such as water can be easily discharged to the outside of the rolling bearing.

Further, at least one of the one or more annular lips is a side lip that extends outward from the outer surface of the elastic sealing member and the tip portion elastically contacts the outward flange of the slinger. Therefore, in a state where the centrifugal force due to the rotation of the outer ring does not act, not only the non-contact seal of the gap seal or the labyrinth seal but also the elastic contact seal can prevent foreign matter such as water from entering the bearing space.

As the elastic sealing member exhibiting the sealing property in this way, when the annular lip comes into contact with the slinger in a sliding state, the elasticity is made of nitrile rubber, acrylic rubber or fluorine rubber having excellent flexibility and abrasion resistance. It is preferable to use a sealing member.

A suitable application for the above-mentioned rolling bearing with a seal for a pulley unit to exert a desired effect is a rolling bearing with a seal for a pulley unit in a belt transmission device of an automobile engine.

In the present invention, in a rolling bearing with a seal for a pulley unit in which two or more annular lips are elastically contacted with a slinger, a gap seal is provided between the outward flange of the slinger and the annular lip, so that the rolling bearing is not provided. When the flange and the annular lip are in a non-contact state and have a sufficient sealing function in a rotating state or a low-speed rotating state, and when the outer ring of the rolling bearing is rotating, the annular lip is elastically deformed by centrifugal force. As a result, the gap of the gap seal is closed, so that the sealing property is good and the water resistance is also excellent both when not rotating and when rotating. This is suitable for, for example, a rolling bearing with a seal for a pulley unit that can constantly prevent the ingress of muddy water and other foreign substances in the harsh usage environment of an automobile.

Further, if the inner surface of the bent portion is a tapered surface having a bending angle of less than 90 degrees, in addition to the above effects, even if foreign matter such as water or muddy water enters the inside of the seal lip, the foreign matter outside the rolling bearing. There is also an advantage that it becomes a rolling bearing with a seal for a pulley unit that can be easily removed.

Sectional drawing of rolling bearing with seal for pulley unit of 1st Embodiment Enlarged sectional view of a main part of FIG. 1 for explaining the usage state of the first embodiment. Enlarged sectional view of the main part of the second embodiment Enlarged sectional view of the main part of the third embodiment Enlarged sectional view of the main part of the fourth embodiment Enlarged sectional view of the main part of the fifth embodiment Enlarged sectional view of a main part of a rolling bearing with a seal explaining the prior art

Embodiments of the present invention will be described below with reference to the accompanying drawings.
As shown in FIGS. 1 and 2, the sealed rolling bearing 1 of the first embodiment is composed of an outer ring 2, an inner ring 3, and a ball bearing having a ball 10 as a rolling element incorporated between the two wheels, and is formed in each row. A sealing member is incorporated on the outside of the ball 10, and both ends of the bearing space formed between the facing surfaces of the outer ring 2 and the inner ring 3 are sealed by the sealing member.

The illustrated rolling bearing 1 with a seal is used for a pulley unit and is incorporated in a state where the outer ring rotates inside a boss portion 6 provided inside the belt guide ring 5 of the pulley 4, and is between the outer ring 2 and the inner ring 3. It has a sealing structure that seals each of the openings at both ends of the formed bearing space.

The sealing member includes a slinger 7 having a substantially L-shaped cross section provided with an outward flange 7b extending radially outward from the outer end of the cylindrical portion 7a fixed to the outer diameter surface end of the inner ring 3, and an outward flange. It has an annular elastic sealing member 8 arranged inside in the axial direction from 7b and having outer peripheral portions fixed to both ends of the inner diameter surface of the outer ring 2. The slinger 7 is made of a press-formed product of a steel plate, and the cylindrical portion 7a is fixed in a state of being press-fitted to the outer diameter surface end portion of the inner ring 3.

The elastic seal member 8 is made of a rubber material that is annular and has substantially rubber-like elasticity as a whole, and is reinforced with an annular core metal 9 that shares an axial center embedded therein. A fitting portion 8a is provided on the outer peripheral portion of the elastic seal member 8 so as to cover the cylindrical portion 9a of the core metal 9, and the fitting portion 8a is a seal mounting groove formed on the inner diameter surface end portion of the outer ring 2. It is press-fitted into 2a and fixed to the outer ring 2.

Further, a radial lip 8b inclined inward is formed on the inner peripheral portion of the elastic seal member 8, and a side lip 8c inclined in the outer radial direction extends outward and its tip portion is elastic on the outward flange 7b. They are in contact with each other to seal the opposing gap between the elastic sealing member 8 and the outward flange 7b. In the present embodiment, the radial lips 8b and 8c are inclined at the same angle, but the present invention is not limited to this, and the radial lips 8b and 8c may be inclined at different angles.

Further, the radial lip 8b provided on the surface of the elastic seal member 8 facing the slinger 7 has a tip end portion arranged on the outer diameter surface of the cylindrical portion 7a of the slinger 7 at a minute interval and is non-contact. A gap seal is formed.

As shown in FIGS. 1 and 2, the slinger 7 of the above-mentioned rolling bearing 1 with a seal for the pulley unit is formed with a bent portion 7c in which the outer peripheral edge of the outward flange 7b is bent inward in the axial direction. There is. The bent portion 7c overlaps the outer ring 2 in the radial direction of the rolling bearing 1. A sub-side lip 8d is provided on the radial inner side of the bent portion 7c on the outermost side in the radial direction of the elastic seal member 8.

The secondary side lip 8d overlaps the bent portion 7c in the axial direction of the rolling bearing 1. Specifically, one end in the axial direction of the sub-side lip 8d (the end on the slinger 7 side) overlaps the bent portion 7c in the axial direction. Then, between the inner side surface 7d of the bent portion 7c and the outer surface of the sub-side lip 8d arranged on the outermost side, a contact seal state (shown by a chain line in FIG. A gap seal (labyrinth seal) that can be used is formed.

The gap seal prevents the passage of liquid foreign matter such as water outside the bearing due to the passage resistance of a small gap when there is a possibility that liquid foreign matter such as water may enter the bearing space from between the slinger 7 and the outer ring 2. It substantially blocks the passage of liquid foreign matter, and the clearance size depends on the shaft diameter and material of the rolling bearing, but for example, the narrowest portion is preferably a gap of about 0.2 to 1.0 mm. ..

As shown in FIG. 2, when the rolling bearing 1 with a seal for the pulley unit of the present embodiment increases the rotation speed of the outer ring 2 in the used state, centrifugal force is applied to both the side lip 8c and the sub side lip 8d. As shown by the arrow in the figure, it acts according to the rotation speed, but the sub-side lip 8d arranged on the outermost side in the radial direction is elastically deformed so as to bend outward in the radial direction due to centrifugal force. The gap seal is closed by pressure contacting the inner side surface 7d of the bent portion 7c of the slinger 7, and the openings at both ends of the bearing space are sealed.

As a result, the side lip 8c, which is another annular lip provided in a state where it can be elastically contacted with the slinger 7, receives centrifugal force due to the rotation of the outer ring of the rolling bearing and is elastic in the state shown by the one-point chain line in FIG. Even when deformed, the decrease in sealing property can be compensated for by the sealing property of the sub-side lip 8d.

In this way, the rolling bearing with a seal for the pulley unit of the first embodiment can prevent the ingress of water, muddy water, and other foreign substances from the outside even when the rolling bearing is submerged in the harsh usage environment of an automobile, for example. A contact seal with 8d ensures protection.

Further, as a material of the elastic sealing member that exhibits the sealing property of the annular lip, considering that the annular lip is elastically pressed against the slinger 7 and used in a sliding state, the sealing property (liquidtightness). ), It is preferable to use a material having excellent flexibility and abrasion resistance, and for example, an elastic sealing member made of nitrile rubber, acrylic rubber or fluorine rubber can be used.

Further, the second embodiment shown in FIG. 3 is exemplified as another form of the gap seal between the smooth surfaces of the outer peripheral surface of the sub-side lip 8d and the inner peripheral surface of the bent portion 7c in the first embodiment. A plurality of rows (4 in the figure) of ridges 11 extending in the circumferential direction are formed on the outer surface of the sub-side lip 8d, and three labyrinth passages 12 are formed between them to form a labyrinth seal. is there.

Further, the third embodiment shown in FIG. 4 is also exemplified as another embodiment of the gap seal in the first embodiment, and is an annular shape arranged on the inner side surface 7d of the bent portion 7c of the outward flange 7b and the outermost side. A square groove portion 13 and a square ridge 14 are arranged to face each other with a gap on both of the two surfaces facing the outer surface of the sub-side lip 8d, which is a lip, to form a four-line labyrinth passage 16. It shows the labyrinth seal.

The labyrinth seals of the second and third embodiments described above are contact-sealed by centrifugal force due to the rotation of the outer ring of the rolling bearing 1 as in the case of the first embodiment, and the rolling bearing 1 is either rotating or non-rotating. However, it can exhibit the same or better sealing property as that of the first embodiment.

Further, in the rolling bearing with a seal for the pulley unit of the fourth embodiment shown in FIG. 5, among the above-mentioned 1 or more annular lips, the sub-side lip 15 arranged on the outermost side in the radial direction has a tip portion 15b from the base portion 15a. The thickness in the radial direction is gradually or stepwise thickened, and the tip portion 15b is formed to be thicker than the base portion 15a.

In the fourth embodiment configured in this way, since a large centrifugal force acts on the tip portion 15b, which is thicker and heavier than the base portion 15a of the sub-side lip 15 in the rotating state of the rolling bearing, comparison is made according to the rotation speed. The tip portion 15b is easily elastically deformed so as to close the labyrinth gap even when rotating at a target low speed, and the openings at both ends of the bearing space are elastically deformed in accordance with the rotation speed to reliably exert a sealing action.

Further, in the rolling bearing with a seal for the pulley unit of the fifth embodiment shown in FIG. 6, the inner surface of the bent portion 7c of the outward flange 7b is formed by a tapered surface having a bending angle θ of less than 90 °. ..

In the fifth embodiment configured in this way, when the rolling bearing stops rotating, the liquid such as water that has infiltrated and accumulated between the elastic sealing member 8 and the slinger 7 is introduced to the bent portion 7c and the secondary side lip. The labyrinth gap with 8d flows down as a downward flow path, and can be efficiently discharged to the outside of the rolling bearing.

The bending angle θ is preferably a small angle that does not bend the flow path as much as possible so as to ensure the drainage action, but on the other hand, in order to improve the sealing property, the centrifugal force due to the rotation of the outer ring of the rolling bearing is used. Even if it is relatively small, it is necessary to efficiently improve the contact sealing property. For that purpose, it is preferable that the bending angle θ is about 45 °, for example, about 30 to 60 °.

Further, in the above-described first to fifth embodiments, the radial lip 8b which is not in contact with the outer diameter surface of the cylindrical portion 7a of the slinger 7 is formed, and the annular lip made of such a radial lip 8b is formed. Also, the one may be elastically contacted with the cylindrical portion 7a.

In the above-described embodiment, the case of a single-row ball bearing is shown as the ball bearing, but as long as the sealing performance is not hindered, a double-row ball bearing or a plurality of single-row ball bearings may be used. For example, a form used in two rows may be adopted.

All of the above-described embodiments can solve the problem in the prior art of "decrease in water resistance due to centrifugal force" of the pulley unit and the like, and reduce the tightening allowance due to the centrifugal force of the rolling bearing used for outer ring rotation. Despite this, it is a rolling bearing with a seal for the pulley unit that can reliably prevent the ingress of muddy water and other foreign matter in the harsh usage environment of automobiles.

1 Rolling bearing with seal 2 Outer ring 2a Seal mounting groove 3 Inner ring 4 Pulley 5 Belt guide ring 6 Boss part 7 Slinger 7a, 9a Cylindrical part 7b Outer flange 7c Bending part 7d Inner side surface 8, 20 Elastic seal member 8a Fitting part 8b Radial lip 8c, 21 Side lip 8d, 15 Secondary side lip 9 Core metal 10 Ball 11, 14 Protrusions 12, 16 Labyrinth passage 13 Square groove 15a Base 15b Tip

Claims (7)

Sealing members that seal both ends of the bearing space formed between the outer ring (2) and the inner ring (3) of the rolling bearing (1) for rotating the outer ring are fixed to the outer diameter surface end of the inner ring (3). An outward flange (7b) is provided at the outer end of the cylindrical portion (7a), and the slinger (7) and the outer ring (7b) are arranged axially inward from the outward flange (7b) of the slinger (7). An annular elastic sealing member (8) having an outer peripheral portion fixed to both ends of the inner diameter surface of 2) is provided, and 2 is provided on the surface of the elastic sealing member (8) facing the slinger (7). In the rolling bearing (1) with a seal for a pulley unit provided with the above annular lip and elastically contacted with the slinger (7).
The rolling bearing (1) is located between the inner surface (7d) of the bent portion (7c) in which the peripheral edge of the outward flange (7b) is bent inward and the outer surface of the annular lip arranged on the outermost side. Rolling bearing with seal for pulley unit (1), which is characterized by providing a gap seal that can be contacted by centrifugal force due to the rotation of the outer ring. According to claim 1, the gap seal forms a labyrinth by having ridges (11, 14) on the outer surface of the annular lip facing the inner surface (7d) of the bent portion (7c). The rolling bearing with a seal for a pulley unit (1). The rolling bearing (1) with a seal for a pulley unit according to claim 1 or 2, wherein the annular lip arranged on the outermost side is an annular lip having a thickness of a tip portion (15b) thicker than that of a base portion (15a). The rolling bearing (1) with a seal for a pulley unit according to any one of claims 1 to 3, wherein the inner surface (7d) of the bent portion (7c) is a tapered surface having a bending angle of less than 90 degrees. At least one of the two or more annular lips extends outward from the outer surface of the elastic sealing member (8), and the tip portion elastically contacts the outward flange (7b) of the slinger (7). The rolling bearing (1) with a seal for a pulley unit according to any one of claims 1 to 4, which is a side lip (8c). The rolling bearing (1) with a seal for a pulley unit according to any one of claims 1 to 5, wherein the elastic seal member (8) is an elastic seal member made of nitrile rubber, acrylic rubber or fluororubber. The rolling bearing (1) with a seal for a pulley unit according to any one of claims 1 to 6, wherein the rolling bearing (1) is a rolling bearing with a seal for a pulley unit in a belt transmission device of an automobile engine.

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