JP2011106603A - Bearing with seal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing with a seal, which prevents the intrusion of foreign matter into the bearing and sufficiently reduces seal torque regardless of the shape of a seal member. <P>SOLUTION: The bearing with the seal includes an inner ring 1, an outer ring 2, rolling elements 3 and the seal member 5. The seal member 5 includes an annular core metal 6 and an elastic member 7 integrally stuck to the core metal 6. The seal member 5, with its base end fixed to the outer ring 2, is of a contact seal and with its seal lip part 5a having an axial lip part 5aa axially contacted to the inner surface of a seal groove 9 formed in the inner ring 1. The material of at least the tip of the axial lip part 5aa is a high wear material worn using the bearing in a rotating state to become a non-contact seal or to come in light contact to the extent that contact pressure can be considered zero. Moreover, the diameter ϕd of the center of radial thickness at the root of the axial lip part 5a is not less than 0.92 times the inner diameter ϕds of the core metal 6. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a bearing with a seal used for a transmission of an automobile or the like.

  Foreign matter such as gear abrasion powder is mixed in the transmission of the automobile. For this reason, a conventional bearing used in an automobile transmission is a bearing with a seal having a contact-type seal member that seals a bearing space formed between inner and outer rings thereof, whereby foreign matter enters the bearing. Is preventing.

When the bearing space is sealed with such a contact-type seal member, foreign matter can be prevented from entering the bearing, but since the seal torque is large, it is a problem in promoting fuel economy of the automobile.
In such a bearing with a seal, shot peeling is applied to the surface on which the seal lip portion is slidably contacted, for example, the inner wall surface of the seal groove of the bearing rotating ring so that the maximum roughness Ry of the contact surface is reduced to 2.5 μm or less, and the seal The thing which reduced the torque is proposed (for example, patent document 1).

JP 2007-107588 A

  Like the bearing with a seal of patent document 1, etc., reducing the surface roughness of the contact surface to reduce the seal torque has a limit in the torque reduction effect. If a non-contact seal is used, the seal torque can be reduced to zero, but reducing the seal gap to such an extent that foreign materials such as gear wear powder can be prevented from entering due to assembly errors, processing errors, thermal expansion differences, etc. It is difficult to realize.

Therefore, the present inventors use a contact type seal member that seals the bearing space as a highly wearable material at the tip of the seal lip portion that contacts the bearing ring, and by using the bearing in a rotating state, We proposed a bearing with a seal in which the tip of the seal lip is worn to become a non-contact seal, or a light contact with which contact pressure can be regarded as zero.
According to this configuration, the contact type seal member at the beginning of operation is changed to a non-contact type seal member at an early stage after the start of operation due to wear, for example. Alternatively, the contact is light enough that the contact pressure can be regarded as zero due to wear. Therefore, it is possible to prevent foreign matter from entering the bearing and sufficiently reduce the sealing torque.

  However, in order to wear the seal member at an early stage after the start of operation, it is necessary to bring the seal lip portion into contact with the raceway with a certain pressure, but the contact pressure varies depending on the shape of the seal member. For this reason, there are cases where the above-described effects cannot be exhibited sufficiently only by using a high wear material as the material of the tip of the seal lip portion of the seal member.

  An object of the present invention is to provide a sealed bearing capable of preventing entry of foreign matter into the bearing and sufficiently reducing a sealing torque regardless of the shape of the seal member.

  A bearing with a seal according to the present invention is the bearing with a seal provided with a seal member for sealing a bearing space formed between the inner and outer rings, in which a plurality of rolling elements are interposed between raceways facing the inner and outer rings. The member is composed of an annular cored bar and an elastic member that is integrally fixed to the cored bar. The base end of the seal member is fixed to the outer ring, and the seal lip is formed on the inner surface of the seal groove formed in the inner ring. A contact seal having an axial lip portion that contacts in the axial direction, and at least the material of the tip end of the axial lip portion is worn to become a non-contact seal or a contact pressure when the bearing is used in a rotating state. It is a high-abrasion material with light contact that can be regarded as zero, and the center diameter of the radial thickness at the base of the axial lip is 0.92 times or more the inner diameter of the cored bar. . In addition, the “high wear material” referred to in this specification indicates a material that is easily worn.

According to this configuration, the material of at least the tip of the axial lip portion of the seal member is a high wear material as described above, and may be referred to as the center diameter of the radial thickness at the root (hereinafter referred to as “root center diameter”). ) Is set to 0.92 times or more of the inner diameter of the cored bar, the axial lip portion of the seal member that becomes a contact type in the initial stage of operation comes into contact with the inner surface of the seal groove of the inner ring with a pressure sufficient for early wear. That is, by increasing the root center diameter of the axial lip portion to a certain percentage or more with respect to the inner diameter of the core metal, it is possible to maintain a pressing force for quickly wearing the tip of the axial lip portion. This ratio is preferably 0.92 times or more, and if it is less than 0.92 times, it does not wear quickly. The term “early wear” as used herein refers to wear until a non-contact seal or a light contact at which contact pressure can be regarded as zero within a time (for example, within 60 minutes) of the bearing running-in operation. . The bearing rotational speed at this time is the rated rotational speed of the bearing (for example, 4000 rpm).
Thus, the contact type seal member at the beginning of operation is changed to a non-contact type seal member, for example, at an early stage after the start of operation due to wear. Alternatively, the contact is light enough that the contact pressure can be regarded as zero due to wear. Therefore, the seal torque can be sufficiently reduced. In addition, due to the wear, a minute gap serving as an optimal non-contact seal gap is formed between the axial lip portion and the inner ring, or light contact as described above is achieved. Therefore, although the lubricating oil can pass through, it is possible to prevent the entry of foreign matters having a large particle size that affect the bearing life. As a result, regardless of the shape of the seal member, it is possible to prevent foreign matter from entering the bearing and sufficiently reduce the seal torque.

  In the present invention, the seal lip portion may include one or more non-contact lip portions that face the seal groove of the inner ring in a non-contact manner in addition to the axial lip portion. As described above, if the seal lip portion has one or more non-contact lip portions in addition to the axial lip portion, a small gap or light gap between the axial lip portion and the inner ring that occurs early after the start of operation. Since the contact and the minute gap between the non-contact lip portion and the inner ring are combined, the effect of preventing foreign matter from entering the bearing can be further enhanced.

In the present invention, the seal member may have the entire axial lip portion or the tip thereof as a high-abrasion material portion which is a material that easily wears against other portions of the seal member.
Since the material that can provide appropriate high wear is limited, it may not be desirable to make the entire seal member highly wearable, but the entire axial lip or only the tip is made of a different material to make it highly wearable. This makes it possible to obtain a preferable high wear property.

  In this invention, the elastic member of the sealing member may be a rubber material or a resin material. When the elastic member is a rubber material, the seal member may be formed by vulcanization molding. Further, when the elastic member is a resin material, the seal member may be formed by injection molding.

In the present invention, the seal member may be provided with an adsorption preventing means for preventing the seal member from adsorbing to the inner ring. This adsorption preventing means is, for example, a ventilation slit provided at the tip of the axial lip portion.
When a contact-type seal member is provided, the seal member may be attracted to the inner ring and torque may increase due to a decrease in bearing internal pressure. In the present invention, a high wear material is used at the tip of the axial lip portion. However, until this portion is worn, an adsorbing action is produced in the same manner as a general contact seal. By providing the suction prevention means such as the slit, the suction until the seal member is worn is prevented, and an increase in torque is avoided.

  The bearing with seal of the present invention may be a transmission bearing used in a transmission of an automobile. When used in automobile transmissions, low torque can contribute to fuel savings in automobiles.

  A bearing with a seal according to the present invention is the bearing with a seal provided with a seal member for sealing a bearing space formed between the inner and outer rings, in which a plurality of rolling elements are interposed between raceways facing the inner and outer rings. The member is composed of an annular cored bar and an elastic member that is integrally fixed to the cored bar. The base end of the seal member is fixed to the outer ring, and the seal lip is formed on the inner surface of the seal groove formed in the inner ring. A contact seal having an axial lip portion that contacts in the axial direction, and at least the material of the tip end of the axial lip portion is worn to become a non-contact seal or a contact pressure when the bearing is used in a rotating state. Since it is a high wear material that can be regarded as light contact that can be regarded as zero, and the diameter at the center of the radial thickness at the base of the axial lip is 0.92 times or more the inner diameter of the metal core, the sealing member Regardless of shape, it is possible to achieve the entry preventing foreign matter into the bearing, a sufficient seal torque reduction.

It is sectional drawing of the bearing with a seal concerning one embodiment of this invention. (A) is an expanded sectional view of the sealing member in the bearing with the seal, and (B) is a sectional view of a modified example of the sealing member. It is an expanded sectional view of the principal part at an early stage after operation of the bearing with the seal. It is sectional drawing of the other modification of the sealing member in the bearing with the said seal | sticker. It is explanatory drawing of the relationship between the base center diameter of the axial lip part in the seal member, and the internal diameter of a metal core. It is an expanded sectional view of the principal part of the bearing with a seal concerning other embodiments of this invention.

  An embodiment of the present invention will be described with reference to FIGS. The sealed bearing according to this embodiment is a rolling bearing used in a transmission of an automobile, and a plurality of rolling elements 3 are interposed between raceway surfaces 1a and 2a of an inner ring 1 and an outer ring 2 to hold these rolling elements 3. A cage 4 is provided, and both ends of an annular bearing space formed between the inner and outer rings 1 and 2 are sealed with seal members 5 respectively. Grease is initially sealed in the bearing. This rolling bearing is a deep groove ball bearing in which the rolling elements 3 are balls, and is an inner ring rotating type in which the inner ring 1 is a rotating ring and the outer ring 2 is a fixed ring. The cage 4 is configured by arranging spherical shells 4 a having pockets 11 for holding the rolling elements 3 side by side in the circumferential direction.

  The seal member 5 includes an annular cored bar 6 and an elastic member 7 that is integrally fixed to the cored bar 6. The seal member 5 has an outer periphery in a seal mounting groove 8 formed on the inner peripheral surface of the outer ring 2 that is a fixed ring. The part is fixed in the fitted state. In the inner ring 1 which is a rotating wheel, a seal groove 9 formed of a circumferential groove is formed at a position corresponding to the inner peripheral portion of each seal member 5. The tip of the seal lip portion 5 a formed at the inner peripheral end of the seal member 5 is in sliding contact with the inner surface of the seal groove 9 of the inner ring 1. The seal lip portion 5a has two axial lip portions 5aa and 5ab branched in a bifurcated manner, as shown in an enlarged sectional view in FIG. The first axial lip portion 5aa extends inward of the bearing and makes axial contact with the inner wall surface of the seal groove 9 of the inner ring 1. The second axial lip portion 5ab extends outside the bearing and makes axial contact with the outer wall surface of the seal groove 9 of the inner ring 1. The seal lip portion 5a is formed as a part of the elastic member 7, but at least a portion including the two axial lip portions 5aa and 5ab including the two axial lip portions 5aa and 5ab is made of a material that easily wears. It is set as the wear material part 7b. In this case, the high wear material portion 7b is made of a high wear rubber material, and the other portion 7a of the elastic member 7 is made of a normal rubber material. The entire seal member 5 is formed by vulcanization molding of a rubber material, and the cored bar 6 is bonded to the elastic member 7 during the vulcanization molding. The type of the high wear rubber material that constitutes the high wear material portion 7b is selected depending on the operating temperature and the compatibility with the lubricating oil.

  FIG. 4 shows a modification of the seal member 5. In this example, the seal lip portion 5a at the tip of the elastic member 7 is not forked as in the case of FIG. 2, but has only one axial lip portion 5aa. As shown in FIG. 5, the axial lip portion 5aa extends inward of the bearing and makes axial contact with the inner wall surface of the seal groove 9 </ b> A of the inner ring 1. In FIG. 5, the seal groove 9 </ b> A of the inner ring 1 is formed as a small diameter step at the outer end of the inner peripheral surface of the inner ring 1. 1 and 5 and FIG. 6 to be described later, the illustration of the seal member 5 shows a state in which the seal member 5 is attached to the outer ring 2 and no external force is applied. Although the tip of the portion 5aa is shown biting from the surface of the seal groove 9, 9A, in practice, the tip of the axial lip portion 5aa is elastically pressed against the surface of the seal groove 9, 9A. .

  In this bearing with seal, as shown in FIG. 5 exemplifying the case of the seal member 5 in FIG. 4, the root 52aaa central diameter φd of the axial lip portion 5aa, that is, the diameter of the center of the radial thickness t at the root is The inner diameter φds of the cored bar 6 is set to 0.92 times or more. This relationship is the same in the case of the seal member 5 illustrated in FIG. 2. In this case, the root center diameter φd of both the axial lip portions 5aa and 5ab is 0.92 times the inner diameter φds of the cored bar 6. It is set above.

  According to the bearing with a seal of this embodiment, at least the tip end portions of the axial lip portions 5aa and 5ab of the seal member 5 that are in sliding contact with the seal groove 9 of the inner ring 1 that is a rotating wheel are made of a material that is easily worn (high wear rubber material). It is set as the high wear material part 7b. In addition, since the tip center diameter φd of the axial lip portions 5aa, 5ab is 0.92 times or more of the inner diameter φds of the cored bar 6, the axial lip portions 5aa, 5ab in the seal member 5 that becomes a contact type in the initial operation are The inner ring 1 comes into contact with the inner surfaces of the seal grooves 9 and 9A with a pressure sufficient for early wear. As a result, the non-contact type seal member 5 as shown in an enlarged cross-sectional view in FIG. 3 at an early stage after the operation is started due to the wear of the high wear material portion 7b. Instead, the seal torque can be sufficiently reduced. The term “early wear” as used herein refers to wear until a non-contact seal or a light contact at which contact pressure can be regarded as zero within a time (for example, within 60 minutes) of the bearing running-in operation. . The bearing rotational speed at this time is the rated rotational speed of the bearing (for example, 4000 rpm). For example, after the start of operation, it becomes non-contact within 60 minutes under oil bath or absolutely dry conditions. As an example of operating conditions, for example, a bearing with a bearing model number: 6207 (JIS standard), a rotational speed of 4000 rpm, a bearing temperature: 30 ° C., and a rotational torque of about 0.075 N · m. Contactless within 60 minutes.

  With respect to the bearing with seal using the seal member 5 shown in FIG. 4, the base center diameter φd of the axial lip portion 5aa and the inner diameter φds of the cored bar 6 in the seal member 5 are made different so Table 1 shows the result of the test on whether or not it wears.

  From this test result, in the sealed bearing of this embodiment in which the root center diameter φd of the axial lip portions 5aa and 5ab is set to 0.92 times or more of the inner diameter φds of the cored bar 6, the axial lip portion 5aa to the inner ring 1 is set. 5ab, it is understood that the pressing force sufficient to wear the axial lip portions 5aa and 5ab at an early stage can be maintained. In the case of 0.90 times less than 0.92 times, early wear does not occur.

Thereby, it is possible to sufficiently reduce the sealing torque regardless of the shape of the seal member 5. As a result, the temperature rise of the bearing can be reduced, and a lubricating oil having a lower viscosity than the conventionally used lubricating oil can be selected. Further, when used in an automobile transmission, it can contribute to fuel saving of the automobile.
In addition, the wear of the high wear material portion 7b forms a minute gap that provides an optimal labyrinth between the axial lip portions 5aa and 5ab of the seal member 5 and the seal grooves 9 and 9A of the inner ring 1. Although it is possible to pass through, it is possible to prevent intrusion of a foreign substance having a large particle diameter that affects the bearing life.
The wear of the high wear material portion 7b does not necessarily occur until it becomes non-contact, and may be wear that is light contact such that the contact pressure can be regarded as practically zero.

In this embodiment, the elastic member 7 of the seal member 5 is a rubber material, and the high wear rubber material is used for the high wear material portion 7b. However, the elastic member 7 of the seal member 5 is a resin material, A high wear resin material may be used for the high wear material portion 7b. In this case, the whole seal member 5 is formed by injection molding of a resin material, and the cored bar 6 is bonded to the elastic member 7 at the time of injection molding. In addition to the above, the material constituting the high wear material portion 7b may be a solid lubricant, a nonwoven fabric, mild steel, or the like.
Further, in this embodiment, as shown in FIG. 2B, the sealing member 5 may be provided with an adsorption preventing means such as a slit 12 for ventilation. The adsorption preventing means is means for preventing the seal member 5 from being adsorbed to the inner ring 1 due to a reduction in the internal pressure of the bearing. In the example of the figure, the axial lip portions 5aa and 5ab of the seal member 5 are in contact with the inner surfaces of the seal grooves 9 in the inner and outer directions of the axial lip portions 5aa and 5ab in contact with the inner surfaces of the seal grooves 9. A slit 12 that is in a vented state is provided. The slits 12 are provided at a plurality of circumferential locations, for example, two locations.
As described above, by providing the suction preventing means such as the slit 12, the seal member 5 is formed on the inner surface of the seal groove 9 of the inner ring 1 in order to reduce the bearing internal pressure until the high wear material portion 7b is worn. Adsorption is prevented and an increase in torque due to adsorption is avoided.

  FIG. 6 shows another embodiment of the present invention. The seal bearing of this embodiment is different from the embodiment shown in FIGS. 1 to 5 in that the seal lip portion 5a of the seal member 5 is in contact with the seal groove 9A of the inner ring 1 in addition to the axial lip portion 5aa. One non-contact lip portion 5ac is opposed to one seal groove 9A in a non-contact manner. There may be two or more non-contact lip portions 5ac. The axial lip portion 5aa may be bifurcated as shown in FIG. At least the tip portion of the axial lip portion 5aa is a high wear material portion 7b made of an easily wearable material, the high wear material portion 7b is made of, for example, a high wear rubber material, and the root center of the axial lip portion 5aa Other configurations such as the diameter φd being set to 0.92 times or more the inner diameter φds of the cored bar 6 are the same as those in the previous embodiment.

  In the case of this embodiment, since the seal lip portion 5a has the non-contact lip portion 5ac in addition to the axial lip portion 5aa, a small gap or light gap between the axial lip portion 5aa and the inner ring 1 that occurs early after the start of operation. Since the contact and the minute gap serving as the labyrinth between the non-contact lip portion 5ac and the inner ring 1 are combined, the effect of preventing foreign matter from entering the bearing can be further enhanced. Similar to the case of the previous embodiment, it is possible to sufficiently reduce the sealing torque, and when used in the tons mission of an automobile, it can contribute to the fuel saving of the automobile.

DESCRIPTION OF SYMBOLS 1 ... Inner ring 2 ... Outer ring 1a, 2a ... Raceway surface 3 ... Rolling element 5 ... Seal member 5a ... Seal lip part 5aa, 5ab ... Axial lip part 5ac ... Non-contact lip part 6 ... Core metal 7 ... Elastic member 7b ... Takama Wear part 8 ... seal mounting groove 9, 9A ... seal groove 12 ... slit (adsorption prevention means)
φd: root center diameter (diameter at the center of the radial thickness at the root)
φds… Inner diameter of cored bar

Claims (9)

In a bearing with a seal including a plurality of rolling elements between opposed raceway surfaces of the inner and outer rings, and a seal member that seals a bearing space formed between the inner and outer rings,
The seal member is composed of an annular cored bar and an elastic member that is integrally fixed to the cored bar. A base end of the seal member is fixed to the outer ring, and a seal lip portion is formed on the inner surface of the seal groove formed on the inner ring. A contact seal having an axial lip portion that contacts in the axial direction against at least the material of the tip end of the axial lip portion, which is worn and becomes a non-contact seal when the bearing is used in a rotating state. It is a high-abrasion material that is lightly contacted so that the pressure can be regarded as zero, and the diameter at the center of the radial thickness at the base of the axial lip portion is 0.92 or more times the inner diameter of the cored bar. Bearing with seal.   2. The bearing with a seal according to claim 1, wherein the seal lip portion includes one or more non-contact lip portions that face the seal groove of the inner ring in a non-contact manner in addition to the axial lip portion.   3. The bearing with a seal according to claim 1, wherein the seal member has the entire axial lip portion or the tip thereof as a high-abrasion material portion which is a material that easily wears against other portions of the seal member.   The bearing with a seal according to any one of claims 1 to 3, wherein the elastic member of the seal member is made of a rubber material.   The bearing with a seal according to claim 4, wherein the seal member is vulcanized.   The bearing with a seal according to any one of claims 1 to 3, wherein the elastic member of the seal member is made of a resin material.   The bearing with a seal according to claim 6, wherein the seal member is injection-molded.   The bearing with a seal according to any one of claims 1 to 7, wherein the seal member is provided with an adsorption prevention means for preventing the seal member from adsorbing to an inner ring. 9. The bearing with a seal according to claim 1, wherein the bearing is a transmission bearing used in a transmission of an automobile.

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