JP6727002B2 - Bearing with seal - Google Patents

Description

The present invention relates to a sealed bearing including a seal that separates the bearing internal space from the outside.

For example, foreign matter such as abrasion powder of gears is mixed in a transmission mounted on a vehicle such as an automobile or various construction machines. Therefore, in the bearing in the transmission, the seal prevents foreign matter from entering the inside of the bearing and prevents early damage of the bearing.

The seal generally has a seal lip and an annulus that fits into the seal mounting portion of the outer ring. The inner ring, which is rotated relative to the outer ring, is formed with a seal groove portion over the entire circumference in the circumferential direction. The outer groove wall of the seal groove portion and the seal mounting portion form a seal inlet into which the seal can be inserted in the axial direction. The lip tip of the seal lip portion is located inside the seal groove portion. The inner side surface of the seal lip portion and the inner side groove wall of the seal groove portion cooperate to perform a sealing action. The outer groove wall of the seal groove portion shields the lip tip of the seal lip portion from the outside. Further, in order to improve foreign matter intrusion resistance and mud water resistance, a labyrinth clearance may be provided between the seal lip and the outer groove wall of the seal groove (Patent Document 1).

JP, 2007-107588, A

However, when the ring part of the seal is fitted into the seal mounting part, the inner side surface of the seal lip part is axially distributed over the entire circumference in the stage before the lip tip of the seal lip part reaches the inside of the seal groove part. From the direction, the outer groove wall of the seal groove portion is strongly rubbed. Generally, since the seal lip portion is formed of an elastomer and the outer ring and the inner ring are formed of steel such as bearing steel, when the inner side surface of the seal lip portion is strongly rubbed against the outer groove wall of the seal groove portion, a large frictional force is generated. It becomes the resistance of the seal insertion. For this reason, it is necessary to set the diameter of the outer lip wall of the seal lip and the seal groove so that the seal can be inserted properly, and there is a limit to the shape modification to improve foreign matter intrusion resistance and mud water resistance. It had been.

In view of the above background, the problem to be solved by the present invention is to improve seal insertability until the seal lip portion reaches the inside of the seal groove portion of the inner ring when the seal ring portion is fitted to the seal mounting portion of the outer ring. It is to improve.

To achieve the above object, the present invention comprises a seal for sealing the inside of a bearing from the outside, an outer ring having a seal mounting portion for holding the seal, and an inner ring arranged coaxially with the outer ring. , The inner ring has a seal groove portion over the entire circumference in the circumferential direction, the seal has a seal lip portion having a lip tip located inside the seal groove portion, and an annular portion fitted to the seal mounting portion. In the bearing with a seal having, a plurality of ridges are formed in circular shapes having different diameters on the inner side of the seal lip portion with the lip tip as a boundary, and the plurality of ridges are When the ring portion and the seal mounting portion are fitted to each other, the contact portions of the seal and the outer groove wall of the seal groove portion are distributed so as to be limited to only the protrusions.

According to the above configuration, when the ring portion of the seal is fitted to the seal mounting portion of the outer ring, the seal lip portion comes into contact with the outer groove wall of the seal groove portion of the inner ring from the outer side and falls to the outer side. To get over the outer gutter wall. At this time, since the seal lip portion contacts the outer groove wall of the seal groove portion only by the circular protrusion formed on the inner side with the lip tip as a boundary, the outer groove wall and the seal lip along the protrusion. There is a gap between the parts. Since the circular ridge can evenly contact the outer groove wall in the circumferential direction, there is no concern that the posture of the seal easily collapses due to the ridge. Since a plurality of ridges are present in circular shapes with different diameters, even if the seal lip portion falls to the outside, two or more ridges can contact the outer groove wall, and these ridges The above-mentioned gap is generated along the line. The gap between the seal lip and the outer groove wall along the circular protrusion reduces the sliding area between the seal lip and the outer groove wall of the seal groove, and reduces the frictional force that resists the seal insertion. ..

As described above, according to the present invention, by adopting the above-described configuration, when the seal ring portion is fitted to the seal mounting portion of the outer ring, the seal insertability is improved until the seal lip portion reaches the inside of the seal groove portion of the inner ring. be able to.

(A) is a partial cross-sectional view showing an initial stage of a seal mounting process of a bearing with a seal according to an embodiment of the present invention, (b) shows that the seal is axially advanced from (a) to bring the seal lip portion into contact with the inner ring. Partial cross-sectional view showing the stage Sectional drawing which shows the bearing with a seal which concerns on 1st Example of this invention. Enlarged cross-sectional view of the vicinity of the seal lip portion of FIG. FIG. 2 is a diagram showing a state in which the vicinity of the seal lip portion of FIG. 2 is viewed in the axial direction from the inside of the bearing. Sectional drawing which shows the seal lip part vicinity based on 2nd Example of this invention. Sectional drawing which shows an example of the transmission provided with the bearing with a seal which concerns on this invention.

A preferred embodiment of the present invention will be described.
In the first embodiment, the seal held by the outer ring is in a non-contact posture with the inner ring, and the minimum clearance between the seal lip portion of the seal and the inner ring is set to less than 0.1 mm. ing.

Bearings for transmissions are required to have low friction while preventing foreign substances from entering the lubricating oil with a seal. When the seal held by the outer ring is in a position in contact with the inner side of the seal groove portion at the seal lip portion, it is possible to suppress the entry of foreign matter, but the seal torque at the contact portion impedes friction reduction. On the other hand, if the seal held by the outer ring is in a non-contact posture with the inner ring, it is possible to reduce the seal torque to zero and achieve a significant reduction in friction, but the seal lip and seal groove are The labyrinth seal that is formed must prevent foreign matter from entering. In order to realize a satisfactory labyrinth seal, it is preferable to set the minimum clearance between the seal lip portion and the inner ring to be less than 0.1 mm. With the conventional seal, the resistance at the time of inserting the seal for fitting the seal ring portion and the seal mounting portion is large, and the posture of the seal held by the outer ring by the fitting can set the minimum clearance of less than 0.1 mm mentioned above It was difficult to manage.
On the other hand, in the present invention, the resistance at the time of inserting the seal is reduced to improve the seal insertability, so that the posture of the seal can be managed to such an extent that the above-mentioned minimum clearance of less than 0.1 mm can be set. .. That is, according to the first embodiment, it is possible to achieve both low friction and suppression of foreign matter intrusion, and a sealed bearing suitable for a transmission application.

A first embodiment according to the present invention will be described with reference to the accompanying drawings. As shown in FIG. 2, the sealed bearing 1 according to the first embodiment has a seal 2 for sealing the inside of the bearing from the outside, an outer ring 4 having a seal mounting portion 3 for holding the seal 2, and an outer ring 4. And the inner ring 5 arranged coaxially. Here, the central axis of the outer ring 4 and the central axis of the inner ring 5 are set coaxially. Hereinafter, the "axial direction" means a direction along the central axes of the outer ring 4 and the inner ring 5, "radial direction" means a direction perpendicular to the axial direction, and "circumferential direction". Indicates the circumferential direction around the central axis.

The outer ring 4 is made of an annular member and has a raceway surface 6 on its inner circumference. The outer ring 4 is attached to the housing of another device. The inner ring 5 is made of an annular member and has a raceway surface 7 on its outer circumference. A plurality of rolling elements 8 are interposed between the raceway surface 6 of the outer ring 4 and the raceway surface 7 of the inner ring 5. A circumferential space between the rolling elements 8 is maintained by a cage 9. The outer ring 4, the inner ring 5, and the plurality of rolling elements 8 mainly constitute a rolling bearing that supports a radial load. The outer ring 4 is attached to a stationary member of another device. The inner ring 5 is attached to a shaft that is rotationally driven by another device. The outer race 4 and the inner race 5 have the illustrated cross-sectional shape over the entire circumference in the circumferential direction.

The outer ring 4 and the inner ring 5 are each made of steel, for example, bearing steel.

The seal 2 includes a seal lip portion 10 formed in a tongue shape in a generally radial direction, a ring portion 11 fitted to the seal mounting portion 3, and a dust formed in a tongue shape in a substantially axial direction. It has a shroud lip portion 12. When the ring portion 11 is press-fitted into the seal mounting portion 3, the seal 2 is held in the predetermined position by the seal mounting portion 3 in the predetermined posture shown in FIG.

The seal lip portion 10 and the dust removing lip portion 12 are each formed of an elastomer. The seal lip portion 10 may be formed of either a rubber material or a resin material. The ring portion 11 is reinforced with a core metal 13. Elastomers such as the seal lip portion 10 and the dust removing lip portion 12 are formed by vulcanization molding and are bonded to the core metal 13.

FIG. 3 is an enlarged view of the vicinity of the seal lip portion 10. As shown in the figure, the surface of the seal lip portion 10 has a lip tip 14 that defines the diameter of the seal lip portion 10, an inner side surface 15 that is a surface portion on the inner side from the lip tip 14, and a lip. It is composed of the tip 14 and an outer side surface 16 composed of a surface portion on the outer side. The vicinity of the lip tip 14 of the inner side surface 15 makes sliding contact with the rotating inner ring 5 to exert a sealing action. The outer side surface 16 and the dust removing lip portion 12 form a labyrinth clearance 17 with the inner ring 5.

The seal mounting portion 3 is formed in a groove shape at the inner peripheral end portion of the outer ring 4 over the entire circumference in the circumferential direction.

The inner ring 5 has a seal groove portion 20 defined by an inner groove wall 18 and an outer groove wall 19 over the entire circumference in the circumferential direction. The outer groove wall 19 and the seal mounting portion 3 form a seal inlet into which the seal 2 can be inserted in the axial direction. In the illustrated example, the groove shoulder of the outer groove wall 19 is lower than the inner groove wall 18, and the groove depth of the seal groove portion 20 is from the groove bottom to the groove shoulder of the outer groove wall 19. The inner surface of the groove of the seal groove portion 20 is composed of the surfaces of the inner groove wall 18 and the outer groove wall 19 which are located within the groove depth from the groove bottom.

Of the groove inner surface of the seal groove portion 20, the surface portion of the inner groove wall 18 is a lip contact surface corresponding to the seal lip portion 10. The lip tip 14 of the seal lip portion 10 is located inside the seal groove portion 20, and the lip tip 14 of the inner side surface 15 is in contact with the surface portion of the inner groove wall 18 with a radial interference.

The diameter dimension A of the outer side groove wall 19 is the diameter at the groove shoulder, and is the outer diameter of the groove shoulder in the illustrated example. The diameter B of the seal lip portion 10 is the diameter at the lip tip 14, and is the inner diameter of the seal 2 in the illustrated example. The tightening margin between the seal lip portion 10 and the outer groove wall 19 corresponds to (B-A).

The diameter B of the seal lip portion 10 is set to be less than 100% of the diameter A of the outer groove wall 19. When the ratio B/A is set to 100% or more, the labyrinth clearance 17 cannot be formed using the outer side groove wall 19, and the outer side groove wall 19 causes the lip tip 14 of the seal lip portion 10 to the outside. Since it cannot be shielded in the axial direction as well, foreign matter easily reaches the contact point between the vicinity of the lip tip 14 and the surface portion of the inner groove wall 18. The ratio B/A is generally set to 97% or more. If the ratio B/A is set to less than 97%, the tightening margin setting between the seal lip portion 10 and the outer groove wall 19 becomes too tight, which may cause difficulty in mounting the seal 2.

FIG. 1A shows that the seal 2 is axially inserted into the seal insertion space between the outer ring 4 and the inner ring 5 which are coaxially arranged, and the ring portion 11 is press-fitted into the seal mounting portion 3 to seal the ring portion 11 and the seal. A state immediately before the seal lip portion 10 comes into contact with the inner ring 5 in a seal fitting process in which the mounting portion 3 is fitted is shown. FIG. 1B shows a state in which the seal 2 is further inserted from the position of FIG. 1A and the seal lip portion 10 is in sliding contact with the outer groove wall 19. FIG. 4 shows a state in which the vicinity of the seal lip portion 10 in a natural state is viewed from the inside in the axial direction.

As shown in FIGS. 1(a) and 4, the inner side surface 15 of the seal lip portion 10 that is bordered by the lip tip 14 has an outer groove wall 19 and an outer groove wall 19 when the ring portion 11 and the seal mounting portion 3 are fitted. Plural ridges 22 are formed between the seal lip portions 10 to secure the gaps 21. These ridges 22 are formed in circular shapes having different diameters, and are arranged at equal intervals in the radial direction. Each ridge 22 has the illustrated cross-sectional shape and extends over the entire circumference in the circumferential direction. The ridge 22 located closest to the inner diameter of the seal 2 exists in the radial region corresponding to the tightening margin (BA), and faces the outer groove wall 19 in the axial direction during the above-described fitting. As apparent from FIG. 1B, when the protrusion 22 comes into contact with the outer groove wall 19 from the outside with the insertion of the seal 2 in the axial direction, the outer groove wall 19 extends along the protrusion 22. A gap 21 is formed between

As is clear from FIGS. 1A and 3, the ridges 22 are also distributed in the radial region that is closer to the outer diameter side from the radial region corresponding to the interference (BA). As shown in FIG. 1B, this is because even if the inner side surface 15 of the seal lip portion 10 is strongly rubbed against the outer groove wall 19, the seal lip portion 10 is entirely tilted outward. This is because the contact portion between the portion 10 and the outer side groove wall 19 is limited to the protrusion 22 only.

The cross-sectional shape of the protrusion 22 in the illustrated example is a solid semicircle. This is so that the protrusion 22 and the outer groove wall 19 are in point contact with each other on the cross section when the ring portion 11 and the seal mounting portion 3 are fitted together, and the direction in which the seal lip portion 10 slides on the outer groove wall 19. This is because the point contact state can be maintained according to the change of. The reference of the protrusion amount of the protrusion 22 is set from the inner peripheral surface 23 of the two peripheral surfaces forming the lip tip 14. The cross-sectional shape and the amount of protrusion of the ridge 22 may be appropriately determined so that the gap 21 can be generated along itself while being in contact with the outer groove wall 19.

By adopting the distribution mode of the protrusions 22 as described above, the sliding contact between the seal lip portion 10 and the outer side groove wall 19 at the time of fitting the ring portion 11 and the seal mounting portion 3 causes the seal lip portion 10 to move to the outer side groove wall 19 Is restricted to occur only between the ridge 22 and the outer groove wall 19 during the entire period from the contact with the inner side of the seal groove 20.

This bearing with seal 1 is as described above, and when the ring portion 11 of the seal 2 is fitted into the seal mounting portion 3 of the outer ring 4 shown in FIG. 2, as shown in FIG. The lip portion 10 axially approaches the outer groove wall 19 of the seal groove portion 20 of the inner ring 5 from the outer side, and first, only the protrusion 22 closest to the inner diameter comes into contact with the groove shoulder chamfer of the outer groove wall 19. .. When the seal 2 is further inserted, as shown in FIG. 1( b ), the seal lip portion 10 falls over to the outer side, and gets over the groove shoulder of the outer side groove wall 19. Two or more ridges 22 of the collapsed seal lip portion 10 come into contact with the outer groove wall 19, and a gap 21 is formed along the ridges 22, 22 adjacent to each other. Since the circular ridge 22 uniformly contacts the outer groove wall 19 in the circumferential direction, there is no concern that the ridge 22 may cause the posture of the seal 2 to collapse. Since a gap is formed between the seal lip portion 10 and the outer side groove wall 19 along the circular protrusion 22, the sliding area between the seal lip portion 10 and the outer side groove wall 19 is reduced, and the frictional force resisting the seal insertion is reduced. Reduce. Therefore, the bearing 1 with a seal can improve the seal insertability until the seal lip portion 10 reaches the inside of the seal groove portion 20 when the seal 2 is mounted.

For example, as a conventional seal, there is one in which the ratio B/A is set to 99.7%, but even if the setting is changed to be smaller by about 1%, it becomes extremely difficult to insert the seal. The inventor of the present application confirmed that the conventional seal has a ratio B/A set to 98.5% and a prototype using a plurality of ridges as in the first embodiment. I was able to get As described above, according to the present invention, the seal insertability can be improved to the extent that the ratio B/A can be set to be smaller than the conventional value by about 1%. For example, the ratio B/A can be set to less than 97%. Will also be possible.

Further, the bearing 1 with seal is formed on the seal lip portion 10 by the protrusion 22. Therefore, it can be easily formed by molding integrally with the seal lip portion 10, and the surface of the outer side groove wall 19 near the groove shoulder is formed. The shape can be a simple cylindrical surface or chamfer as in the conventional case.

It is, of course, preferable to reduce the friction coefficient of the ridges 22, and the surface treatment of the elastomer forming the ridges 22, for example, the ridges 22 with a coating such as a thermosetting paint that is harder than the elastomer is used. It may be covered to reduce the coefficient of friction.

A bearing with a seal according to a second embodiment of the present invention will be described.
The sealed bearing according to the second embodiment differs from the first embodiment only in that the seal is changed to a non-contact type seal. For this reason, in the following, common reference numerals will be used while appropriately referring to the drawings used in the description of the first embodiment. FIG. 5 shows an enlarged view of the vicinity of the seal lip portion in the state of FIG. 2 of the second embodiment.

As shown in FIGS. 2 and 5, in the second embodiment, the seal 2 held by the outer ring 4 is in a non-contact posture with the inner ring 5. The minimum clearance g between the seal lip portion 10 of the seal 2 and the inner ring 5 is formed between the lip tip 14 of the seal lip portion 10 and the inner groove wall 18 of the inner ring 5.

In the second embodiment, the ratio B/A of the diameter B of the seal lip portion 10 and the diameter A of the outer groove wall 19 is set to 98% or more and less than 99% where good seal insertability is confirmed. There is. As a result, the minimum clearance g for the posture of the seal 2 held by the outer ring 4 can be set to less than 0.1 mm. During operation of the bearing, the seal 2 and the inner ring 5 are not normally in contact with each other, and the seal torque is kept at zero.

Further, in the labyrinth seal formed by the seal lip portion 10 and the seal groove portion 20 of the inner ring 5, the minimum clearance g between the seal lip portion 10 and the inner ring 5 is set to less than 0.1 mm. It is particularly narrow between the lip portions 10. Therefore, it becomes very difficult for foreign matter to pass through the minimum clearance g from the outside with the lip tip 14 as a boundary. Therefore, even if the non-contact type seal 2 is adopted, it is possible to suppress the entry of foreign matter to the extent that there is no fear of adversely affecting the bearing life.

As described above, the sealed bearing according to the second embodiment can achieve both low friction by normally setting the seal torque of the seal 2 to zero and suppression of foreign matter intrusion, and is suitable for transmission applications. It becomes a bearing with various seals.

The bearing 1 with a seal can be used, for example, to support a shaft included in a transmission for an automobile. The transmission 100 illustrated in FIG. 6 is a manual type, in which an input shaft 102, an output shaft 103 and a pilot shaft 104 are arranged in series in a housing 101, and a counter shaft 105 and a reverse shaft 106 are connected to the output shaft 103. The structure is arranged in parallel. The reverse shaft 106 is also adapted to engage with the output shaft 103. Each of the shafts 102 to 106 is provided with a large number of gear groups, and the clutch hub 107 that is shifted by an external operation changes the meshing of these gear groups to change the input shaft 102 to the output shaft 103. The torque transmission path of is properly selected. In this transmission 100, an input shaft 102, an output shaft 103, a pilot shaft 104, a counter shaft 105, and a gear member 108 attached to one end side of the counter shaft 105 are supported by a bearing 1 with a seal. As an example of the application of the sealed bearing 1, the example of being incorporated in the transmission 100 has been shown. However, other applications of the sealed bearing 1 include, for example, a vehicle differential, a constant velocity joint, a propeller shaft, a turbocharger, and a work machine. Applications include machines, wind power generators, or wheel bearings.

The embodiments and examples disclosed this time are to be considered as illustrative in all points and not restrictive. Therefore, the scope of the present invention is defined not by the above description but by the scope of the claims, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.

1 Bearing with seal 2 Seal 3 Seal mounting part 4 Outer ring 5 Inner ring 10 Seal lip part 11 Ring part 14 Lip tip 18 Internal groove wall 19 External groove wall 20 Seal groove part 21 Gap 22 Projection 100 Transmission

Claims (5)

A seal for sealing the inside of the bearing from the outside, an outer ring having a seal mounting portion for holding the seal, and an inner ring arranged coaxially with the outer ring,
The inner ring has a seal groove portion over the entire circumference in the circumferential direction,
In the sealed bearing, wherein the seal has a seal lip portion having a lip tip located inside the seal groove portion, and a ring portion fitted to the seal mounting portion,
On the inner side of the seal lip portion with the lip tip as a boundary, a plurality of ridges are formed in circular shapes having different diameters,
The plurality of ridges are distributed so as to limit the contact points of the seal and the outer groove wall of the seal groove portion to only the ridges when the ring portion and the seal mounting portion are fitted together,
When the ring portion is fitted to the seal mounting portion, the protrusion located closest to the inner diameter of the seal among the plurality of protrusions comes into contact with the outer groove wall of the seal groove, and the shaft of the seal. A bearing with a seal, characterized in that at least two of said ridges of said seal lip portion which are tilted due to insertion in a direction come into contact with an outer groove wall of said seal groove portion . The seal held by the outer ring is in a non-contact posture with the inner ring, and the minimum clearance between the seal lip portion of the seal and the inner ring is set to less than 0.1 mm. Bearing with seal as described. The bearing with a seal according to claim 1 or 2, wherein the diameter of the seal lip portion is set to 97% or more and less than 100% of the diameter of the outer groove wall of the seal groove portion. The sealed bearing according to any one of claims 1 to 3, wherein the seal lip portion is formed of a rubber material or a resin material. The sealed bearing according to any one of claims 1 to 4, which is incorporated in a transmission of a vehicle.

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