JP2010019296A - Bearing with seal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing with a seal capable of preventing the intrusion of a foreign matter into the bearing and reducing the seal torque sufficiently, and to apply the bearing to a transmission and the like. <P>SOLUTION: The bearing with a seal includes an outer ring 2, an inner ring 1, rollers 3, and a seal member 5. This seal member 5 is fixed to the outer ring 2 at its base end and the other end, which contacts the inner ring 1 slidably, forms a seal lip part 5a. The part including at least the tip end of the seal lip part 5a forms a high abrasion material part 7b made of an easy-to-wear material. <P>COPYRIGHT: (C)2010,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 sealed bearing having a contact-type seal member that seals a bearing space formed between the inner and outer rings, 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

  As in the bearing with a seal of Patent Document 1, reducing the surface roughness of the contact surface and reducing 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.

  An object of the present invention is to provide a sealed bearing capable of preventing foreign matter from entering the bearing and sufficiently reducing the sealing torque.

A bearing with a seal according to the present invention is a bearing with a seal provided with a seal member that seals a bearing space formed between the pair of raceways, with a plurality of rolling elements interposed between raceways facing each other. The seal member is a contact seal whose base end is fixed to one of the race rings and whose seal lip portion is in contact with the other race ring, and at least the material of the tip of the seal lip portion rotates the bearing. It is characterized by being a high wear material that wears to become a non-contact seal or light contact that can be regarded as having zero contact pressure. In addition, the “high wear material” referred to in this specification indicates a material that is easily worn.
According to this configuration, since the material of at least the tip of the seal lip portion of the seal member is the high wear material as described above, the seal member that was a contact type at the beginning of the operation is worn early, for example, after the start of operation. It changes to a non-contact type seal member. 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 seal lip portion and the rotating wheel, 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, it is possible to prevent foreign matter from entering the bearing and sufficiently reduce the sealing torque.

In the present invention, the seal member may have the entire or tip of the seal lip portion as a high wear material portion that 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 preferable to make the entire seal member highly wearable, but the entire seal 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.

  The high wear material may be a rubber material, that is, a high wear rubber material, or may be a resin material. In addition to this, the high wear material may be a solid lubricant, non-woven fabric, hard steel, or the like.

  In this invention, the shape of the sealing member may be an axial contact type or a radial contact type. For example, the seal lip portion may have a shape that makes contact in the axial direction with respect to the inner surface of the seal groove formed in the opposed raceway ring. Moreover, it is good also as a shape which a seal lip part contacts in a radial direction with respect to the raceway which opposes.

In this invention, the seal member may be provided with an adsorption preventing means for preventing the seal member from adsorbing to the other race ring. The adsorption preventing means is, for example, a ventilation slit provided at the tip of the seal member.
When a contact-type seal member is provided, the seal member may be attracted to the race and the torque may increase due to a decrease in bearing internal pressure. Although the present invention uses a high wear material, an adsorbing action occurs like a general contact seal until the seal member is worn. 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.

  A bearing with a seal according to the present invention includes a plurality of rolling elements between opposing raceway surfaces of a pair of races, and a seal bearing provided with a seal member that seals a bearing space formed between the pair of races. The seal member is a contact seal whose base end is fixed to one of the race rings and whose seal lip portion is in contact with the other race ring, and at least the material of the tip of the seal lip portion rotates the bearing. Because it is a high-wear material that wears and becomes a non-contact seal or a light contact that can be regarded as having zero contact pressure, it prevents foreign matter from entering the bearing and sufficiently reduces seal torque. Can be achieved.

  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, and these rolling elements 3 are held. 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. The inner ring 1 and the outer ring 2 are a pair of track rings referred to in the claims. 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 a cage with ridges having ridges 4b on the outer peripheral surface of a spherical shell 4a having pockets 11 for holding the rolling elements 3.

  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. As shown in the enlarged sectional view of FIG. 2, the seal lip portion 5a has two axial lip portions 5aa and 5ab that are bifurcated. 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.

According to the bearing with seal of this embodiment, at least the tip end portion of the seal lip portion 5a of the seal member 5 that is in sliding contact with the seal groove 9 of the inner ring 1 that is a rotating wheel is made of a highly wearable material (high wear rubber material). Since it is the wear material portion 7b, the seal member 5 which was a contact type in the initial stage of operation is enlarged in FIG. 3 at an early stage (several hours after the start of operation) after the start of operation due to wear of the high wear material portion 7b. As shown in the figure, the seal torque can be sufficiently reduced in place of the non-contact type seal member 5. 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 of 30 ° C., and a rotational torque of about 0.075 N · m. Contactless within 60 minutes.
Thereby, it is possible to sufficiently reduce the sealing torque. 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.
Further, the wear of the high wear material portion 7b forms a minute gap that provides an optimum labyrinth between the seal lip portion 5a of the seal member 5 and the seal groove 9 of the inner ring 1, so that the lubricating oil can pass therethrough. However, 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 zero in practical use.

In this embodiment, the case where a high wear rubber material is used as the material that easily wears that constitutes the high wear material portion 7b of the seal member 5 is illustrated, but a resin material is used as another example of the material that easily wears. May be. 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 in several places in the circumferential direction, for example, two places.
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 raceway groove 9 of the inner ring 1 in order to reduce the bearing internal pressure until the high wear material portion 7 is worn. Adsorption is prevented and an increase in torque due to adsorption is avoided.

  FIG. 4 is a graph showing the test results comparing the rotational torque of the sealed bearing of this embodiment with a conventional sealed bearing. As shown in FIG. 4A, the rotational torque is significantly reduced in the sealed bearing of the embodiment as compared with the conventional product. The reason for this is that, as shown in FIG. 4B, the breakdown of the causes of rotational torque includes resistance due to grease, cage shear resistance + rolling resistance, and seal torque, as shown in FIG. This is because the seal torque factor is eliminated in the sealed bearing of the form.

  FIG. 5 shows another embodiment of the present invention. In the embodiment shown in FIGS. 1 to 4, the bearing with seal of this embodiment is a single radial lip in which the seal lip portion 5 a of the seal member 5 extends radially to the seal groove 9 of the inner ring 1. It has part 5ac. At least the tip end portion having the radial lip portion 5ac of the seal lip portion 5a is made to be a high wear material portion 7b made of an easily wearable material, the high wear material portion 7b made of a high wear rubber material, The configuration of is the same as that of the previous embodiment.

  Also in this embodiment, foreign matter can be prevented from entering the bearing, and a sufficient seal torque can be reduced. When used in an automobile transmission, it can contribute to fuel saving of the automobile.

  FIG. 6 shows another embodiment of the present invention. In the sealed bearing of this embodiment, in the embodiment shown in FIGS. 1 to 4, the seal lip portion 5 a of the seal member 5 extends inside the bearing and makes axial contact with the inner wall surface of the seal groove 9 of the inner ring 1. It has only one axial lip 5aa. The portion 7b including at least the tip portion of the seal lip portion 5a including the axial lip portion 5aa is a high wear material portion made of a material that easily wears, or the high wear material portion 7b is made of a high wear rubber material. The other configurations are the same as those of the embodiment of FIGS.

  Also in this embodiment, foreign matter can be prevented from entering the bearing and a sufficient seal torque can be reduced. When used in an automobile transmission, it can contribute to fuel saving of the automobile.

  In each of the embodiments described above, the case where the present invention is applied to an inner ring rotation type rolling bearing has been described. However, the same effects as described above can be achieved even if the present invention is applied to an outer ring rotation type rolling bearing or a thrust bearing.

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 the graph which showed the rotational torque of the bearing with the seal compared with the conventional product. (A) is a half sectional view of a bearing with a seal according to another embodiment of the present invention, and (B) is an enlarged sectional view of an essential part thereof. (A) is a half sectional view of a bearing with a seal according to still another embodiment of the present invention, and (B) is an enlarged sectional view of an essential part thereof.

Explanation of symbols

1 ... Inner ring (Raceway)
2 ... Outer ring (Raceway)
1a, 2a ... raceway surface 3 ... rolling element 5 ... seal member 5a ... seal lip part 5aa, 5ab ... axial lip part 5ac ... radial lip part 7 ... high wear material part 8 ... seal mounting groove 9 ... seal groove 12 ... slit ( Adsorption prevention means)

Claims (7)

In a bearing with a seal including a plurality of rolling elements between opposing raceway surfaces of a pair of races, and having a seal member that seals a bearing space formed between the pair of races,
The seal member is a contact seal in which a base end is fixed to one of the race rings and a seal lip portion is in contact with the other race ring, and at least the material of the tip of the seal lip portion is used in a rotating state of the bearing. Thus, a bearing with a seal is characterized by being a high-abrasion material that wears to become a non-contact seal or a light contact that can be regarded as having a contact pressure of zero.   2. The bearing with a seal according to claim 1, wherein the seal member has the entire seal 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 claim 1 or 2, wherein the high wear material is a rubber material.   The sealed bearing according to claim 1 or 2, wherein the high wear material is a resin material.   The bearing with a seal according to any one of claims 1 to 4, wherein the seal lip portion of the seal member is in a shape in contact with an inner surface of a seal groove formed in an opposing raceway in an axial direction.   The bearing with a seal according to any one of claims 1 to 4, wherein the seal lip portion of the seal member has a shape that comes into contact with a facing race in a radial direction.   The bearing with a seal according to any one of claims 1 to 6, wherein the seal member is provided with an adsorption preventing means for preventing the seal member from adsorbing to the other race ring.

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