JP2017048870A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device which can be attached into a narrow space without lowering sealing performance, and is flexibly adapted to manufacturing at a sealing specification which is required without causing the facture or the like of a seal lip.SOLUTION: A sealing device includes: a first metal ring 9 which is fit to an inner ring 6; a second metal ring 10 which is fit to an outer ring 2; and a seal member 11 which is arranged between the first metal ring and the second metal ring. The first metal ring has a first fitting cylinder part 91 which is fit to the inner ring, and a first non-fitting cylinder part 92, and the second metal ring has a second fitting cylinder part 101 which is fit to the outer ring, and a second non-fitting cylinder part 102. The seal member has a seal lip 13 which is arranged at an outer opening part Sa side which is surrounded by the first metal ring and the second metal ring, made to firmly adhere to a core grid 12 fit to the non-fitting cylinder part which is located at an inside-diameter side out of the first non-fitting cylinder part and the second non-fitting cylinder part, and contacts with or approximates the non-fitting cylinder part located at an outside-diameter side at its tip part 13a. The tip part of the seal lip is orientated to the outer opening part side.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a sealing device that seals between the outer ring and the inner ring on the flange portion side in a bearing device including an inner ring having a flange portion and an outer ring, such as a hub bearing for an automobile.

  In the case of the above-described automobile hub bearing, a hub ring is used as an inner ring, and the hub ring has a flange portion (hub flange) extending outward (outer radial direction) at one end, and the wheel is attached to the hub flange. Mounted. The hub wheel is supported by the outer ring on the fixed side so as to be capable of rotating the shaft via a rolling element. An annular bearing space constituted by a hub ring (inner ring) and an outer ring is sealed by a sealing device mounted at both axial ends between the outer ring and the inner ring (see, for example, Patent Document 1 and Patent Document 2). Further, Patent Document 3 discloses a bearing device for a wheel support portion of a railway vehicle, not an automobile. In Patent Document 3, a front cover or a rear cover that is a separate member from the inner ring and an outer ring are disclosed. The sealing device to be mounted on is described. These sealing devices prevent the intrusion of muddy water containing dust (hereinafter referred to as muddy water) into the bearing space and the external leakage of lubricants such as grease filled in the bearing space. Is maintained for a long time.

JP 2008-261409 A EP2821662A1 JP 2002-195278 A

  By the way, depending on the specifications of the bearing device, it may be difficult to ensure a sufficient space in a portion where the sealing device is mounted. Particularly, in the case of a hub flange side (outer side or wheel side) sealing device, the inner diameter side of the outer ring may occupy more space for the rolling elements and the retainers that support the rolling elements. In such a case, if the bearing device shown in Patent Document 1 is taken as an example, it may be difficult to assemble a sealing device such as the second hermetic seal of the same document. Therefore, if only the first hermetic seal is used, there is only one seal lip, and it is difficult to provide a plurality of seal lips structurally, and sufficient sealing performance cannot be obtained.

  On the other hand, in Patent Document 2, a metal ring fitted to the annular step portion of the hub flange, another metal ring fitted to the outer peripheral surface of the hub flange side end portion of the outer ring, and both metal rings A sealing device is disclosed that includes a plurality of sealing lips fixed to one side and elastically contacting the other metal ring. According to the sealing device disclosed in Patent Document 2, it is considered that the problem in Patent Document 1 is unlikely to occur. However, it is considered that the plurality of seal lips are integrally fixed to one metal ring by molding. However, in the manufacturing process by actual molding, it is difficult to remove the seal lip because of the structure, and the seal lip Is expected to break during die cutting. In addition, the sealing device disclosed in Patent Document 3 has a seal case fitted into the end of the outer ring, and a metal core having a partition plate and a lip portion integrally fitted to the seal case. A cylindrical member is externally fitted to the front lid, and a plurality of lip portions constituting the lip portion are close to the cylindrical member. In this case, it is technically different from the structural complexity that the inner ring is not involved and the inner ring and the outer ring are sealed.

  The present invention has been made in view of the above circumstances, and can be mounted in a narrow space without deteriorating the sealing performance, and can be easily manufactured by molding without causing the seal lip to break. An object of the present invention is to provide a sealing device that can flexibly meet the required sealing specifications.

  A sealing device according to the present invention is a sealing device that seals between an outer ring and an inner ring of a bearing device, and includes a first metal ring fitted to the inner ring and a second metal ring fitted to the outer ring. And a seal member provided between the first metal ring and the second metal ring, and the first metal ring includes a first fitting cylindrical portion fitted to the inner ring, and the first fitting A first non-fitting cylindrical part integral with the cylindrical part, and the second metal ring includes a second fitting cylindrical part fitted to the outer ring, and a first fitting cylindrical part integrated with the second fitting cylindrical part. Two non-fitting cylindrical parts, and the seal member is located on the outer opening side that communicates with the outside of the bearing device in the opening part of the space surrounded by the first metal ring and the second metal ring. The seal member is provided so as to be positioned, and the seal member is fitted to a non-fitting cylindrical part located on the inner diameter side of the first non-fitting cylindrical part and the second non-fitting cylindrical part. And a seal lip that is fixedly attached to the core metal so as to extend in the outer diameter direction, and a tip portion of the seal lip is in contact with or close to a non-fitting cylindrical portion located on the outer diameter side. It is configured to face the opening side.

  According to the present invention, the sealing device of the present invention is configured by providing the seal member between the first metal ring fitted to the inner ring and the second metal ring fitted to the outer ring. Even when the mounting space is narrow due to the positional relationship of the outer ring, etc., it can be dealt with by designing the fitting part of the first metal ring and the second metal ring, the shape thereof, and the like. Since the seal member is disposed in the space surrounded by the first metal ring and the second metal ring, the seal lip is covered by the first non-fitting cylindrical part and the second non-fitting cylindrical part. Thus, it is protected from muddy water containing dust that is about to enter from outside the bearing device. In particular, the sealing member is fitted to a non-fitting cylindrical part located on the inner diameter side of the first non-fitting cylindrical part and the second non-fitting cylindrical part, and the non-fitting cylindrical part located on the outer diameter side is Since it will be located so that the muddy water etc. which penetrate | invade from an outward opening part may be shielded, it becomes difficult for muddy water etc. to reach the front-end | tip part of a seal lip. And since the front-end | tip part of a seal lip is arrange | positioned so that it may contact or adjoin to the non-fitting cylindrical part located in the outer-diameter side, the muddy water from the outside of a bearing apparatus becomes difficult to reach | attain by the front-end | tip part of a seal lip. . Thereby, the biting of dust between the tip portion and the non-fitting cylindrical portion on the outer diameter side is suppressed, and the tip portion is hardly worn, and excellent sealing performance is exhibited. In addition, since the tip of the seal lip is configured to face the outer opening side of the space, the muddy water or the like that has entered the space is not fitted to the tip of the seal lip and the outer diameter side of the cylinder. It does not enter between the two parts, flows down through the sealing device, is discharged from the lower outer opening, and does not stay in the sealing device. Thereby, more excellent sealing performance is exhibited. Further, since the seal member is constituted by the cored bar and the seal lip, the manufacture thereof is facilitated by molding, particularly compression molding. Furthermore, since the seal member is fitted to the first metal ring or the second metal ring, the number of the seal members can be increased as necessary, and the flexibility is very useful.

In the sealing device according to the aspect of the invention, a sub-seal member that is arranged in parallel along the axial direction with respect to the seal member is further provided between the first metal ring and the second metal ring, and the sub-seal member is the seal member The opening of the space is provided to be located on the inner opening side leading to the inside of the bearing device, and the sub seal member includes the first non-fitting cylindrical part and the second non-fitting cylindrical part. A sub-core that is fitted to one of them, and a sub-seal lip that is fixed to the sub-core so as to extend in the radial direction and whose tip is in contact with or close to the other non-fitting cylindrical portion It is also good.
According to this, in addition to the seal member, the sub seal member is provided in parallel with the seal member, so that the sealing performance is further improved. The number of the sub-seal members is appropriately set according to the required sealing specifications (seal performance), and further fitted to either the first non-fitting cylindrical part or the second non-fitting cylindrical part. Alternatively, the direction of the tip portion can be set as appropriate.

In the sealing device of the present invention, the first non-fitting cylindrical portion and the second non-fitting cylindrical portion may be configured to face each other in the radial direction.
According to this, the length of the seal lip of the seal member interposed between the first non-fitting cylindrical part and the second non-fitting cylindrical part can be reduced, and the production of the seal member by molding is a mold of the seal lip. It can be achieved more accurately without causing breakage or the like at the time of punching.

In the sealing device of the present invention, the outer opening may be configured to open in the radial direction.
According to this, the amount of muddy water or the like arriving at the tip of the seal lip from the outside of the bearing device is reduced, and the muddy water or the like entering the sealing device is more quickly discharged.

In the sealing device of the present invention, the following various aspects can be adopted as the basic shapes of the first metal ring and the second metal ring.
a) The first fitting cylindrical portion and the first non-fitting cylindrical portion in the first metal ring have different radial sizes.
b) A case where the first fitting cylindrical portion and the first non-fitting cylindrical portion in the first metal ring have the same radial size.
c) When the radial size of the second fitting cylindrical part and the second non-fitting cylindrical part in the second metal ring are different.
d) The radial size of the second fitting cylindrical part and the second non-fitting cylindrical part in the second metal ring are the same.
The basic shapes of the first metal ring and the second metal ring shown in the embodiments a) to d) are appropriately selected and adopted according to the structure of the bearing device to which the sealing device is mounted.

  According to the sealing device of the present invention, it can be mounted in a narrow space without reducing the sealing performance, and can be easily manufactured by molding without causing the seal lip to break and the like. The seal specification can be flexibly supported.

It is a schematic sectional drawing which shows an example of the bearing apparatus with which the sealing device which concerns on this invention was mounted | worn. It is 1st embodiment of the sealing device which concerns on this invention, Comprising: It is an enlarged view of the X section of FIG. It is a figure similar to FIG. 2 which shows the 1st modification of the embodiment. It is a figure similar to FIG. 2 which shows the 2nd modification of the embodiment. It is a figure similar to FIG. 2 which shows 2nd embodiment of the sealing device which concerns on this invention. It is a figure similar to FIG. 2 which shows 3rd embodiment of the sealing device which concerns on this invention. It is the same figure as FIG. 2 which shows the modification of the embodiment. It is a figure similar to FIG. 2 which shows 4th embodiment of the sealing device which concerns on this invention.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a bearing device equipped with a sealing device according to the present invention. A bearing device 1 shown in FIG. 1 is a hub bearing that rotatably supports a driven wheel of an automobile. A hub bearing (bearing device) 1 shown in the figure has a hub wheel 4 and an inner ring member (simply annular) via two rows of rolling elements (balls) 3... On an inner diameter portion of an outer ring 2 fixed to a vehicle body (not shown). 5 (also referred to as a member) is supported so as to be rotatable around the axis L. The hub wheel 4 has a hub flange (outward flange portion) 41, and a driven wheel (tire wheel) (not shown) is attached to the hub flange 41 with a bolt 42. An inner ring 6 is constituted by the hub ring 4 and the inner ring member 5, and the rolling elements 3 are held between the outer ring 2 and the inner ring 6 by the retainer 3 a, and the outer ring side raceway ring 2 a of the outer ring 2. And the hub ring 4 and the inner ring side raceway rings 4a and 5a of the inner ring member 5 are interposed so as to roll. The hub ring 4 and the inner ring member 5 are integrated by caulking one end portion 40 of the hub ring 4 to the inner ring member 5. An annular bearing space BS as a sealed space is formed between the outer ring 2 and the inner ring 6 including the intervening portion of the rolling elements 3..., And the rolling elements 3. A lubricant (for example, grease) is filled.
In the following, the left side of FIG. 1 is referred to as the wheel side, and the right side is referred to as the vehicle body side.

  A cap 7 that seals the opening 20 of the outer ring 2 is fitted to the end of the outer ring 2 on the vehicle body side in the bearing space BS. A bearing seal 8 is mounted between the end of the outer ring 2 on the wheel side and the inner ring 6 (hub wheel 4) so as to be slidable with respect to the inner ring 6 (hub wheel 4). The cap 7 and the bearing seal 8 constitute a sealing device that seals the bearing space BS. The both sealing devices (cap 7 and bearing seal 8) prevent intrusion of muddy water or the like into the bearing space BS and prevent external leakage of the lubricant (grease etc.) filled in the bearing space BS. . The cap 7 in the illustrated example includes a cylindrical part 71 fitted (externally fitted) to the vehicle body side end 21 of the outer ring 2 and a sheet metal workpiece having a lid part 72 integral with the cylindrical part 71. By fitting 71 to the outer peripheral surface 21 a of the vehicle body side end portion 21, the opening 20 of the outer ring 2 is sealed. And in order to prevent intrusion of muddy water or the like into the metal fitting portion between the cylindrical portion 71 and the outer peripheral surface 21a of the vehicle body side end portion 21 in the outer ring 2, the outer surface of the cylindrical portion 71 is covered and a part thereof is the outer periphery. A rubber seal portion 73 that is elastically adhered to the surface 21a is integrally provided by vulcanization molding. Among the sealing devices 7 and 8, the sealing device according to the present invention is applied to the wheel-side bearing seal 8.

  With reference also to FIG. 2, the first embodiment of the sealing device according to the present invention will be described in detail. The bearing seal (sealing device) 8 of this embodiment includes a first metal ring 9 fitted to the inner ring 6, a second metal ring 10 fitted to the outer ring 2, the first metal ring 9 and the second metal. And a seal member 11 provided between the rings 10. The first metal ring 9 includes a first fitting cylindrical portion 91 that is externally fitted to an annular step portion 41a centered on an axis L (see FIG. 1) formed on the hub flange 41, and a first fitting cylinder. And a first non-fitting cylindrical portion 92 having a larger diameter than the portion 91. More specifically, a first ring portion 93 extending in the outer diameter direction from the vehicle body side end portion of the first fitting cylindrical portion 91 is integrally connected, and the first fitting is started from the outer peripheral edge portion of the first ring portion 93. A first non-fitting cylindrical portion 92 is integrally connected to the combined cylindrical portion 91 toward the vehicle body side coaxially. That is, in the present embodiment, the first fitting cylindrical portion 91 and the first non-fitting cylindrical portion 92 in the first metal ring 9 have different radial sizes. The second metal ring 10 includes a second fitting cylindrical portion 101 fitted on the wheel side outer peripheral surface 22 a of the wheel side end portion 22 in the outer ring 2, and a second diameter smaller than the second fitting cylindrical portion 101. And a non-fitting cylindrical portion 102. More specifically, a second annular portion 103 extending in the inner diameter direction from the wheel side end of the second fitting cylindrical portion 101 is integrally connected, and the second fitting is performed from the inner peripheral edge of the second annular portion 103. A second non-fitting cylindrical portion 102 is integrally connected to the cylindrical portion 91 toward the vehicle body side coaxially. That is, in the present embodiment, the radial size of the second fitting cylindrical portion 101 and the second non-fitting cylindrical portion 102 in the second metal ring 10 is different. The first non-fitting cylindrical part 92 and the second non-fitting cylindrical part 102 are opposed to each other in the radial direction, and the second non-fitting cylindrical part 102 has an inner diameter greater than that of the first non-fitting cylindrical part 92. It is configured to be located on the side. The first fitting cylindrical part 91, the first non-fitting cylindrical part 92, the second fitting cylindrical part 101, and the second non-fitting cylindrical part 102 are externally fitted to the step part 41a of the first fitting cylindrical part 91. And in the external fitting state with respect to the wheel side outer peripheral surface 22a of the outer ring | wheel 2 of the 2nd fitting cylindrical part 101, it is comprised so that it may become coaxial centering on the axis | shaft L. As shown in FIG. When the second metal ring 10 is externally fitted to the outer ring 2, the side surface 103 b of the vehicle body side of the second circular ring portion 103 is in close contact with the wheel side end surface 22 b of the outer ring 2.

  The seal member 11 of this embodiment is fitted (externally fitted) to the second non-fitting cylindrical portion 102 located on the inner diameter side. The seal member 11 is provided so as to be positioned on the outer opening Sa side that communicates with the outside of the bearing device 1 in the openings Sa and Sb of the space S surrounded by the first metal ring 9 and the second metal ring 10. ing. Furthermore, the seal member 11 is fixedly attached to the core metal 12 to be fitted (externally fitted) to the second non-fitting cylindrical portion 102, and is extended to the core metal 12 so as to extend in the outer diameter direction. A seal lip 13 that elastically contacts the positioned first non-fitting cylindrical portion 92, and the tip end portion 13a of the seal lip 13 is configured to face the outward opening side Sa. The cored bar 12 includes a cored bar cylindrical part 12a fitted to the outer peripheral surface 102b of the second non-fitted cylindrical part 102, and a cored bar annular part extending from the wheel side end of the cored bar cylindrical part 12a to the outer diameter side. 12b. The seal lip 13 is integrally formed by vulcanizing and molding an elastomer such as rubber to the core metal 12 and is fixed to the core metal cylindrical portion 12a and the core metal ring portion 12b of the core metal 12. 13b is extended as described above.

  In the present embodiment, one sub-seal member 120 is further provided between the first metal ring 9 and the second metal ring 10 in parallel with the seal member 11 along the axis L direction. The sub seal member 120 is provided so as to be positioned on the inner opening Sb side leading to the inside (bearing space BS) of the bearing device 1 in the space S from the seal member 11. Further, the sub seal member 120 is fixed to the sub cored bar 121 fitted to the first non-fitting cylindrical part 92 and the sub-core bar 121 so as to extend in the inner diameter direction, and the tip part 122a is a second non-fitted cylindrical part. And a sub seal lip 122 that elastically contacts the portion 102. And the front-end | tip part 122a of the sub seal lip 122 is comprised so that it may face in the outward opening part Sa side of the space S. FIG. The sub cored bar 121 includes a sub cored bar cylindrical part 121a fitted in the first non-fitting cylindrical part 92, and a sub cored bar ring part 121b extending from the wheel side end of the sub cored bar cylindrical part 121a to the inner diameter side. And have. The sub-seal lip 122 is integrally formed by vulcanizing and molding an elastomer such as rubber to the sub-core metal 121, and extends from the lip base portion 122b fixed to the sub-core metal 121 as described above. Yes. In the present embodiment, the rubber (elastomer) covering portion 104 that covers the entire outer peripheral surface 101 a of the second fitting cylindrical portion 101 in the second metal ring 10 and a part of the wheel side surface 103 a of the second annular portion 103. Are integrally formed. The rubber covering portion 104 includes an annular inward protrusion 104a that wraps around the vehicle body side end surface 101b of the second fitting cylindrical portion 101 and is interposed between the outer peripheral surface 22a of the outer ring 2 in a compressed state, and a second circle. It has an annular flange 104b that protrudes from the ring portion 103 toward the wheel side and is positioned on the outer diameter side of the outer opening Sa. In the figure, an annular inward projection 104a indicated by a two-dot chain line indicates the original shape before compression. The outer opening Sa is in the radial direction (outer diameter direction) between the tip end portion 92a of the first non-fitting cylindrical portion 92 and the portion of the rubber covering portion 104 that covers the wheel side surface 103a of the second annular portion 103. It is comprised so that it may open to. Further, the inner opening Sb of the space S is radially (inner diameter direction) between the tip end portion 102a of the second non-fitting cylindrical portion 102 and the flange surface 41b on the inner diameter side of the stepped portion 41a in the hub flange 41. It is comprised so that it may open.

A procedure for mounting the bearing seal 8 configured in this manner on the bearing device 1 will be described briefly. First, after the sub seal member 120 is fitted into the first non-fitting cylindrical portion 92 of the first metal ring 9 via the sub-core metal cylindrical portion 121a, the first metal ring 9 is fitted to the first fitting cylindrical portion. The outer flange 91 is fitted on the step 41 a of the hub flange 41 through 91. Next, after the sealing member 11 is externally fitted to the second non-fitting cylindrical portion 102 of the second metal ring 10 via the core metal cylindrical portion 12a, the second metal ring 10 is fitted to the second fitting cylindrical portion 101. And is fitted on the wheel side end 22 of the outer ring 2. The outer fitting of the second metal ring 10 to the outer ring 2 is such that the vehicle body side surface 103b of the second annular ring portion 103 is in close contact with the wheel side end surface 22b of the outer ring 2, and the annular inward projection 104a is second fitted. It is made to interpose in a compressed state between the combined cylindrical portion 101 and the wheel side outer peripheral surface 22a of the outer ring 2. The distal end portion 92a of the first non-fitting cylindrical portion 92 is a guide portion formed in an outward taper shape so that the inner fitting with respect to the first non-fitting cylindrical portion 92 of the sub seal member 120 can be smoothly performed. The tip portion 102a of the second non-fitting cylindrical portion 102 is a guide portion formed in an inwardly tapered shape so that the outer fitting with respect to the second non-fitting cylindrical portion 102 of the seal member 11 can be smoothly performed. Yes. Then, the inner ring 6 fitted with the first metal ring 9 and the outer ring 2 fitted with the second metal ring 10 are connected to each other through the ball 3 (see FIG. 1) and the retainer 3a. Assemble each other in position. As a result, the bearing seal 8 is mounted between the wheel end 22 of the outer ring 2 and the inner ring 6 in the bearing device 1. In this mounted state, the first non-fitting cylindrical portion 92 and the second non-fitting cylindrical portion 102 are positioned in a radial relationship so that the former is on the outer diameter side and the latter is on the inner diameter side. Further, the seal member 11 and the sub seal member 120 are in a state where the tip portions 13a and 122a of the seal lips 13 and 122 are in elastic contact with the first non-fitting cylindrical portion 92 and the second non-fitting cylindrical portion 102, respectively. It is interposed between the first metal ring 9 and the second metal ring 10. In the drawing, the tip portions 13a and 122a of the seal lips 13 and 122 indicated by the two-dot chain line are original shapes before elastically deforming when elastically contacting the first non-fitting cylindrical portion 92 and the second non-fitting cylindrical portion 102. (The same applies to the following examples).
In addition, in this embodiment, although it has comprised so that the front-end | tip parts 13a and 122a of the seal lips 13 and 122 may each elastically contact the 1st non-fitting cylindrical part 92 and the 2nd non-fitting cylindrical part 102, it adjoins. It may be configured as described above.

  In the hub bearing 1 to which the bearing seal 8 is mounted as described above, the inner ring 6 rotates around the axis L while being supported by the outer ring 2 via the balls 3. As the shaft of the inner ring 6 rotates, the tip portions 13a and 122a of the seal member 11 and the sub seal member 120 are brought into contact with the inner peripheral surface 92b of the first non-fitting cylindrical portion 92 and the outer peripheral surface 102b of the second non-fitting cylindrical portion 102. Relative sliding contact is made in the state of elastic contact. This prevents intrusion of muddy water or the like into the bearing space BS from the hub flange 41 side and external leakage of the lubricant filled in the bearing space BS. And since the seal member 11 and the sub seal member 120 are arrange | positioned in the space S enclosed by the 1st metal ring 9 and the 2nd metal ring 10, the seal lips 13 and 122 are the 1st non-fitting cylindrical part. 92 and the second non-fitting cylindrical portion 102 are covered, and are protected from muddy water or the like containing dust to enter from outside the hub bearing 1. In particular, the seal member 11 is fitted to the second non-fitting cylindrical portion 102 located on the inner diameter side, and the first non-fitting cylindrical portion 92 located on the outer diameter side enters muddy water or the like from the outer opening Sa. Therefore, it is difficult for muddy water or the like to reach the front end portion 13a of the seal lip 13.

  Further, since the tip end portion 13a of the seal lip 13 is arranged so as to elastically contact the first non-fitting cylindrical portion 92 located on the outer diameter side, muddy water or the like that is about to enter from the outside of the hub bearing 1 is sealed with the seal lip 13. It becomes difficult to reach by the front end portion 13a. Thereby, the biting of dust between the tip portion 13a and the inner peripheral surface 92b of the first non-fitting cylindrical portion 92 is suppressed, and the tip portion 13a is less likely to be worn, and excellent sealing performance is exhibited. Is done. Moreover, since the tip end portion 13a of the seal lip 13 is configured to face the outer opening Sa of the space S, the muddy water or the like that has entered the space S is in contact with the tip end portion 13a of the seal lip 13 and the first end portion 13a. It does not enter between the non-fitting cylindrical portion 92, flows down in the bearing seal 8, is quickly discharged from the lower outer opening Sa, and does not stay in the bearing seal 8. Furthermore, since the sub seal member 120 is provided so as to be located downstream of the seal member 11 in the muddy water intrusion direction, the tip portion 13a of the seal lip 13 and the first non-fitting cylindrical portion 92 Even if a part of muddy water or the like passes through the elastic sliding contact portion, further infiltration of muddy water or the like is prevented by the sub seal member 120. As a result, intrusion of muddy water or the like from the hub flange 41 side into the bearing space BS is more reliably prevented. In addition, in the present embodiment, since the flanged portion 104b of the rubber covering portion 104 is positioned so as to cover the outer diameter side portion of the outer opening Sa, muddy water or the like from the outside of the hub bearing 1 into the space S, etc. Infiltration is suppressed. Further, the annular inward protruding portion 104a of the rubber covering portion 104 wraps around the vehicle body side end portion 101b of the second fitting cylindrical portion 101 and is interposed in a compressed state between the outer ring 2 and the wheel side outer peripheral surface 22a. Therefore, there is no concern that muddy water or the like enters the metal fitting portion between the second fitting cylindrical portion and the outer ring 2. As a result, rusting of the metal fitting portion is suppressed, a decrease in fitting force with time is suppressed, and intrusion of muddy water or the like from the fitting portion directly into the bearing space BS is difficult to occur.

  The seal member 11 and the sub seal member 120 can be easily formed without causing the seal lip 13 and the sub seal lip 122 to break by molding the seal lip 13 and the sub seal lip 122 to the core metal 12 and the sub core metal 121. Can be manufactured. Further, since the first non-fitting cylindrical portion 92 and the second non-fitting cylindrical portion 102 are configured to face each other in the radial direction, the lengths of the seal lip 13 and the sub seal lip 122 can be reduced. This makes it possible to make the seal lip 13 and the sub seal lip 122 less likely to break during die cutting. Furthermore, if a plurality of seal members 11 and a plurality of sub seal members 120 are prepared, a more accurate seal design can be performed according to the required seal specifications, etc. by appropriately selecting and setting these numbers. Flexibility can be increased. In addition, in the present embodiment, the first metal ring 9 shaped as shown in the figure is externally fitted to the step 41a of the hub lunge 41, and the second metal ring 10 shaped as shown in the figure is fitted to the outer ring 2. Since the bearing seal 8 is configured, the bearing seal 8 can be mounted even if the space on the inner diameter side of the outer ring 2 is narrow due to the presence of the retainer 3a and the like.

  FIG. 3 shows a first modification of the first embodiment. In the bearing seal (sealing device) 8 of this example, the first metal ring 9 is fitted on the stepped portion 41 a of the hub flange 41, and the second metal ring 10 is fitted on the wheel side end 22 of the outer ring 2. This is common to the example shown in FIG. The first metal ring 9 has a first fitting cylindrical part 91, a first non-fitting cylindrical part 92, and a first annular part 93, and the second metal ring 10 is fitted first. The point which has the cylindrical part 101, the 2nd non-fitting cylindrical part 102, and the 2nd ring part 103, and these positional relationships are also common in the example shown in FIG. In particular, the example shown in FIG. 2 is such that the first non-fitting cylindrical portion 92 and the second non-fitting cylindrical portion 102 are opposed to each other in the radial direction, and the former is located on the outer diameter side and the latter is located on the inner diameter side. And in common. Further, the second metal ring 10 is provided with a rubber covering portion 104 as in the example of FIG. However, instead of the sub seal member 120 shown in FIG. 2, two sub seal members 130 and 130 are provided, and the second metal ring 10 extends from the second non-fitting cylindrical portion 102 with an L-shaped cross section. It differs from the example shown in FIG. 2 in that the part 105 is further extended. The extended portion 105 includes an extended circular ring portion 105a extending from the tip end portion 102a of the second non-fitting cylindrical portion 102 of the second metal ring 10 toward the inner diameter side with a small gap from the flange surface 41b of the hub flange 41. And an extended cylindrical portion 105b that is refracted toward the vehicle body side from the inner peripheral edge of the extended ring portion 105a and extends parallel to the axis L. The inward opening portion Sb of the space S is configured to open in the radial direction (inner diameter direction) between the flange surface 41b and the extended ring portion 105a.

  In the present embodiment, the two sub-seal members 130 and 130 have the same shape as the seal member 11 and are fitted (externally fitted) to the second non-fitting cylindrical portion 102 located on the inner diameter side, and the seal member 11 is provided so as to be parallel to the downstream side (wheel side) in the infiltration direction of muddy water or the like along the axis L direction. More specifically, both the sub seal members 130 are fixed to the sub cored bar 131 fitted to the second non-fitted cylindrical part 102 and the sub cored bar 131 so as to extend in the outer diameter direction, and the tip end part 132a is externally attached. A sub seal lip 132 elastically contacting the inner peripheral surface 92b of the first non-fitting cylindrical portion 92 located on the radial side, and the tip end portion 132a of the sub seal lip 132 is configured to face the outward opening side Sa. ing. The sub cored bar 131 includes a sub cored bar cylindrical part 131a that is externally fitted to the second non-fitted cylindrical part 102, and a sub cored bar annular part that extends to the outer diameter side from the wheel side end of the sub cored bar cylindrical part 131a. 131b. The sub-seal lip 132 is integrally formed by vulcanizing and molding an elastomer such as rubber to the sub-core bar 131, and the lip base 132 b fixed to the sub-core bar 131 is connected to the seal lip 13 of the seal member 11. It is extended as well.

The bearing seal 8 in this example is also mounted between the outer ring 2 and the inner ring 6 on the wheel side in the hub bearing 1. As the inner ring 6 rotates, the tip end portion 13 a of the seal lip 13 in the seal member 11 and the tip end portions 132 a and 132 a of the sub seal lips 132 and 132 in the sub seal members 130 and 130 are It is elastically slidably contacted with the inner peripheral surface 92b. As a result, the seal member 11 has a sealing function similar to that of the example shown in FIG. 2, and the two sub-seal members 130 and 130 synergistically complement the seal member 11. In particular, both the sub-seal members 130 and 130 are fitted on the second non-fitting cylindrical portion 102 located on the inner diameter side, and the tip portions 132a and 132a are formed so as to face the outward opening Sa of the space S. Therefore, even if a part of the muddy water passes through the first seal member 11, the intrusion of muddy water or the like into the elastic contact portion between the tip end portions 132a, 132a and the second non-fitting cylindrical portion 102 is prevented. . In addition, the presence of the extending portion 105 that is refracted to have an L-shaped cross section reliably prevents the lubricant filled in the bearing space BS from entering the space S. In particular, if the gap between the extended ring portion 105a of the extended portion 105 and the flange surface 41b is reduced to provide a labyrinth structure, the effect of preventing the lubricant from entering the space S is more effectively exhibited. .
Since the other configuration is the same as that of the example shown in FIG. 2, the same reference numerals are given to the common parts, and the description of the operation and effect is omitted.

FIG. 4 shows a second modification of the first embodiment. The bearing seal (sealing device) 8 of this example is the same as the example shown in FIG. 2 in the basic shape of the first metal ring 9 and the second metal ring 10, but has no sub seal member 120, and 2 is different from the example shown in FIG. 2 in that the tip portion 102a of the non-fitting cylindrical portion 102 is caulked to the seal member 11 side. In the illustrated example, the distal end portion 102 a is caulked so as to contact the core metal ring portion 12 b constituting the seal member 11. Also in the bearing seal 8 configured as described above, the seal member 11 has the same sealing function as the example shown in FIG. And since the front-end | tip part 102a of the 2nd non-fitting cylindrical part 102 is crimped to the seal member 11 side, the fitting state with respect to the 2nd non-fitting cylindrical part 102 of the seal member 11 is stabilized.
In addition, even if it does not crimp the front-end | tip part 102a of the 2nd non-fitting cylindrical part 102, it shall try to stabilize a fitting state by setting the fitting tightening allowance with respect to the 2nd non-fitting cylindrical part 102 of the sealing member 11. May be. The same applies to the seal members and sub-seal members of other embodiments. Since the other configuration is the same as that of the example shown in FIG. 2, the same reference numerals are given to the common parts, and the description of the operations and effects will be omitted.

FIG. 5 shows a second embodiment of the sealing device according to the present invention. In the bearing seal (sealing device) 8 of the present embodiment, the first fitting cylindrical portion 91 and the first non-fitting cylindrical portion 92 constituting the first metal ring 9 have the same diameter, that is, the radial size of both. Are characterized by being identical. Therefore, the 1st metal ring 9 does not have the 1st ring part 93 like the above-mentioned example, but the 1st fitting cylinder part 91 and the 1st non-fitting cylinder part 92 are connected with straight shape. . The second metal ring 10 is configured similarly to the example shown in FIG. The first non-fitting cylindrical part 92 and the second non-fitting cylindrical part 102 are opposed to each other in the radial direction, and the second non-fitting cylindrical part 102 has an inner diameter greater than that of the first non-fitting cylindrical part 92. It is configured to be located on the side. In the present embodiment, one sub seal member 130 similar to the example shown in FIG. 3 is provided, and the seal member 11 and the sub seal member 130 are arranged in parallel in the axis L direction via the core metal 12 and the sub core metal 131, respectively. The second fitting cylindrical portion 102 is externally fitted. Thereby, the seal member 11 has the same sealing function as the example shown in FIG. 2, and the sub seal member 130 has a sealing function that complements the seal member 11.
Other configurations are the same as those in the example shown in FIG. 2 or FIG.

  FIG. 6 shows a third embodiment of the sealing device according to the present invention. In the bearing seal (sealing device) 8 of the present embodiment, the first fitting cylindrical part 91 and the first non-fitting cylindrical part 92 constituting the first metal ring 9 have the same diameter as in the example shown in FIG. In addition to being (second embodiment), the second fitting cylindrical part 101 and the second non-fitting cylindrical part 102 constituting the second metal ring 10 are characterized by the same diameter. That is, the radial direction sizes of the second fitting cylindrical part 101 and the second non-fitting cylindrical part 102 are the same. Therefore, the second metal ring 10 does not have the second annular portion 103 as in the above example, and the second fitting cylindrical portion 101 and the second non-fitting cylindrical portion 102 are connected in a straight line. . The first fitting cylindrical portion 91 and the first non-fitting cylindrical portion 92 in the first metal ring 9 have the same radial size as in the example shown in FIG. The first fitting cylindrical portion 91 is integrally provided with a partition-like annular wall 94 along the outer diameter direction by fitting (outer fitting) or the like. The first non-fitting cylindrical part 92 and the second non-fitting cylindrical part 102 are opposed to each other in the radial direction, and the first non-fitting cylindrical part 92 is outside the second non-fitting cylindrical part 102. It is configured to be positioned on the radial side. The annular wall 94 is provided so as to be close to the tip end 102 a of the second non-fitting cylindrical portion 102, and the wall 94 and the tip end 102 a of the second non-fitting cylindrical portion 102 open to the outside of the space S. The part Sa is configured to open in the radial direction. Further, the inner opening Sb of the space S is configured to open in the radial direction (inner diameter direction) between the tip end portion 92a of the first non-fitting cylindrical portion 92 and the wheel side end surface 22b of the outer ring 2. Yes. Therefore, it differs from the above embodiments in that the outer opening Sa is located on the wheel side and the inner opening Sb is located on the vehicle body side.

  The seal member 11 is provided so as to be positioned on the outer opening Sa side (wheel side) of the space S surrounded by the first metal ring 9 and the second metal ring 10. The seal member 11 is fixed to the core metal 12 to be fitted (externally fitted) to the outer peripheral surface 92c of the first non-fitting cylindrical portion 92, and is fixed to the core metal 12 so as to extend in the outer diameter direction. And a seal lip 13 that elastically contacts the inner peripheral surface 102c of the non-fitting cylindrical portion 102. The seal lip 13 extends from a lip base portion 13b that is fixed and integrated with the core metal 12 in the same manner as in the above example, and the tip end portion 13a faces the outward opening portion Sa. The cored bar 12 has a cored bar cylindrical part 12a fitted over the first non-fitted cylindrical part 92, and a cored bar ring part 12b extending from the vehicle body side end of the cored bar cylindrical part 12a to the outer diameter side. doing.

  A sub seal member 140 is provided on the inner opening Sb side of the seal member 11 in parallel with the seal member 11 along the axis L direction. The sub-seal member 140 is fixed to the sub-core metal 141 that is fitted (externally fitted) to the outer peripheral surface 92c of the first non-fitting cylindrical portion 92, and is fixed to the sub-core metal 141 so as to extend in the outer diameter direction. And a sub seal lip 142 elastically contacting the inner peripheral surface 102c of the second non-fitting cylindrical portion 102. The sub seal lip 142 is configured to extend from a lip base portion 142b that is fixedly integrated with the sub metal core 141, and a tip end portion 142a thereof faces the outer opening Sa. The sub-core metal 12 includes a sub-core metal cylindrical portion 12a that is externally fitted to the first non-fitting cylindrical portion 92, and a sub-core metal annular portion that extends from the vehicle body side end of the sub-core metal cylindrical portion 12a to the outer diameter side. 12b. Further, the sub seal member 140 of the present embodiment includes a second sub seal lip 143 that extends from the lip base portion 142b to the outer ring 2 side, and the front end portion 143a elastically contacts the wheel side end surface of the outer ring 2, and the front end portion 143a. Is configured to face toward the inward opening Sb.

Also in the bearing seal 8 of the present embodiment, the seal member 11 has the same sealing function as the example shown in FIG. 2, and the sub seal member 140 has a sealing function that complements the seal member 11. In particular, since the sub-seal member 140 includes the second sub-seal lip 143, a sealing function that complements the seal member 11 is more effectively exhibited. In addition, since the tip portion 143a of the second sub seal lip 143 is configured to face the inner opening Sb, it faces the leakage direction of the lubricant filled in the bearing space BS. Thus, it is effective for suppressing the penetration of the lubricant into the space S. Furthermore, since the annular wall body 94 is provided in the first fitting cylindrical portion 91 so as to be close to the tip end portion 102a of the second non-fitting cylindrical portion 102, entry of mud water into the space S is suppressed. Also made.
Since the other configuration is the same as that of the example shown in FIG. 5, the same reference numerals are given to the common parts, and the description of the operations and effects will be omitted.

  FIG. 7 shows a modification of the third embodiment. In the bearing seal (sealing device) 8 of the present embodiment, the first fitting cylindrical portion 91 and the first non-fitting cylindrical portion 92 constituting the first metal ring 9 have the same radial size, and the second The second fitting cylindrical portion 101 and the second non-fitting cylindrical portion 102 constituting the metal ring 10 have the same radial size as the example shown in FIG. Similarly to the example shown in FIG. 6, the first non-fitting cylindrical portion 92 and the second non-fitting cylindrical portion 102 are configured to face each other in the radial direction. The second non-fitting portion 102 is positioned on the inner diameter side of the first non-fitting cylindrical portion 92, and the second fitting cylindrical portion 101 is fitted inside the inner peripheral surface 22 c of the wheel side end portion 22 of the outer ring 2. This is different from the example shown in FIG. The outer opening Sa in the space S surrounded by the first metal ring 9 and the second metal ring 10 is between the tip end portion 92a of the first non-fitting cylindrical portion 92 and the wheel side end surface 22b of the outer ring 2. It is configured to open in the radial direction (outer diameter direction). Further, the inward opening Sb is configured to open in the radial direction (inner diameter direction) between the distal end portion 102a of the second non-fitting cylindrical portion 102 and the flange surface 41b.

  A seal member 11 and one sub seal member 150 are provided between the first metal ring 9 and the second metal ring 10. The seal member 11 is functionally the same as the above examples, although the outer shape is different, and is provided so as to be positioned on the outer opening Sa side (vehicle body side) of the space S. The seal member 11 is fitted to the second non-fitting cylindrical portion 102 (externally fitted), and is fixed to the core metal 12 so as to extend in the outer diameter direction, and the distal end portion 13a is the first non-fitted cylinder. And a seal lip 13 that elastically contacts the inner peripheral surface 92 b of the portion 92. The cored bar 12 includes a cored bar cylindrical part 12a fitted to the outer peripheral surface 102b of the second non-fitted cylindrical part 102, and a cored bar annular part extending in the outer diameter direction from the wheel side end of the cored bar cylindrical part 12a. The seal lip 13 is configured to extend from a lip base portion 13b fixed to the core metal ring portion 12b so that the tip end portion 13a faces the outer opening Sa. The sub seal member 150 is fixed to the sub metal core 151 to be fitted (internally fitted) to the first non-fitting cylindrical portion 92, and is fixed to the sub metal core 151 so as to extend in the inner diameter direction. A sub seal lip 152 elastically contacting the outer peripheral surface 102b of the cylindrical portion 102 is provided. The sub metal core 151 includes a sub metal core cylinder portion 151a that is fitted to the inner peripheral surface 92a of the first fitting cylindrical portion 92, and a sub metal core that extends in the inner diameter direction from the vehicle body side end portion of the sub metal core cylinder portion 151a. The sub seal lip 152 extends from a lip base portion 152b fixed to the sub core metal ring portion 151b so that the tip end portion 152a faces the inner opening Sb. Has been.

Also in the bearing seal 8 of the present embodiment, the seal member 11 has the same sealing function as the example shown in FIG. 2, and the sub seal member 150 has a sealing function that complements the seal member 11. In particular, since the sub seal member 150 is configured such that the front end portion 152a of the sub seal lip 152 faces the inner opening Sb, the sub seal member 150 faces the leakage direction of the lubricant filled in the bearing space BS. That is, it is effective for suppressing the penetration of the lubricant into the space S. In the example shown in FIG. 6 and the present embodiment, the first metal ring 9 and the second metal ring 10 are both straight rings, but the radial positional relationship between them and the fitting of the second metal ring 10 to the outer ring 2 The conjugation site is different. The difference between the first metal ring 9 and the second metal ring 10 is appropriately selected and adopted from the positional relationship between the outer ring 2 and the stepped portion 41a of the hub flange 41.
Since the other configuration is the same as that of the example shown in FIG. 6, the same reference numerals are given to the common parts, and the description of the operation and effect is omitted.

  FIG. 8 shows a fourth embodiment of the sealing device according to the present invention. In the bearing seal (sealing device) 8 of this embodiment, the first non-fitting cylindrical part 92 constituting the first metal ring 9 and the second non-fitting cylindrical part 102 constituting the second metal ring 10 are in the radial direction. Is characterized by being slightly displaced in the direction of the axis L. And the core metal 12 which comprises the sealing member 11 consists only of the core metal cylindrical part 12a fitted to the 2nd non-fitting cylindrical part 102 (external fitting). The seal lip 13 is extended from a lip base portion 13b fixed to the cored bar cylindrical portion 12a, the tip end portion 13a is elastically contacted with the inner peripheral surface 92b of the first non-fitting cylindrical portion 92, and It is configured to face toward the opening Sa. As in the example shown in FIG. 2, the first metal ring 9 includes a first fitting cylindrical part 91, a first annular ring part 93, and a first non-fitting cylindrical part 92. The second metal ring 10 includes a second fitting cylindrical portion 101 fitted (externally fitted) to the outer peripheral surface 22a of the wheel side end portion 22 of the outer ring 2, and a wheel side end portion of the second fitting cylindrical portion 101. An outward flange portion 105 bent to the outer diameter side, a second annular portion 103 folded back from the outer peripheral edge portion of the outward flange portion 105, and a wheel side from the inner peripheral edge portion of the second annular portion 103 And a second non-fitting cylindrical portion 102 that is continuous with the first portion. The first non-fitting cylindrical portion 92 constituting the first metal ring 9 is located on the outer diameter side than the second non-fitting cylindrical portion 102 constituting the first metal ring 10 and is located on the inner diameter side. The sealing member 11 is fitted (externally fitted) to the fitting cylindrical portion 102. In a state where the second metal ring 10 is fitted to the outer ring 2, the side surface 103 a of the second circular ring portion 103 is in close contact with the end surface 22 b on the vehicle body side of the outer ring 2. The outer opening Sa of the space S opens in the radial direction (outer radial direction) between the tip end portion 92a of the first non-fitting cylindrical portion 92 and the wheel side surface 103a of the second annular ring portion 103, and the lip Between the base portion 13b and the flange surface 41b of the hub flange 41, the inner opening Sb of the space S is configured to open in the radial direction (inner diameter direction).

Also in the belling seal 8 of the present embodiment, the sealing member 11 exhibits the same sealing function as in each of the examples as in the above examples. In addition, since the outward saddle-shaped portion 105 and a part of the second annular ring portion 103 connected thereto are formed so as to protrude from the outer peripheral surface 22a of the outer ring 2 to the outer diameter side, this shielding function can Intrusion into the space S is suppressed.
Although the shape of the seal lip 13 constituting the seal member 11 is different from the shape of each of the above examples, this is merely an example, and it is possible to apply other shapes to the present embodiment. is there. In addition, the sub seal member shown in another example can be added to the present embodiment. Since other configurations are the same as those in the above example, common portions are denoted by the same reference numerals, and descriptions of operations and effects thereof are omitted.

  The radial size of the first fitting cylindrical portion 91 and the first non-fitting cylindrical portion 92 constituting the first metal ring 9, and the second fitting cylindrical portion 101 constituting the second metal ring 10, Examples in which the radial size with the second non-fitting cylindrical portion 102 is different, examples that are the same, and examples of combinations thereof are not limited to those illustrated, but the radial direction between the step 41a of the hub flange 41 and the outer ring 2 The position is appropriately changed according to the specifications of the bearing device 1 and the like. Further, the shape and the like of the seal lip constituting the seal member and the sub seal member are not limited to those shown in the drawings, and can be appropriately changed. Furthermore, although the example in which the sealing device of the present invention is applied to a hub bearing for a driven wheel for an automobile has been described, the present invention is not limited to this and can be applied to a hub bearing for a driving wheel and a bearing device for other industrial machines. is there.

1 Hub bearing (bearing device)
2 Outer ring 6 Inner ring 8 Bearing seal (sealing device)
DESCRIPTION OF SYMBOLS 9 1st metal ring 91 1st fitting cylindrical part 92 1st non-fitting cylindrical part 10 2nd metal ring 101 2nd fitting cylindrical part 102 2nd non-fitting cylindrical part 11 Seal member 12 Core metal 13 Seal lip 13a Front end portion of seal lip 120, 130, 140, 150 Sub seal member 121, 131, 141, 151 Sub core metal 122, 132, 142, 152 Sub seal lip 122a, 132a, 142a, 152a Front end portion of sub seal lip S Space Sa Outer opening Sb Inner opening L axis

Claims (8)

A sealing device for sealing between an outer ring and an inner ring of a bearing device,
A first metal ring fitted to the inner ring, a second metal ring fitted to the outer ring, and a seal member provided between the first metal ring and the second metal ring,
The first metal ring has a first fitting cylindrical part fitted to the inner ring, and a first non-fitting cylindrical part integrated with the first fitting cylindrical part,
The second metal ring has a second fitting cylindrical part fitted to the outer ring, and a second non-fitting cylindrical part integrated with the second fitting cylindrical part,
The seal member is provided so as to be positioned on the outer opening side communicating with the outside of the bearing device in the opening portion of the space surrounded by the first metal ring and the second metal ring, A cored bar that is fitted to a non-fitted cylindrical part located on the inner diameter side of the first non-fitted cylindrical part and the second non-fitted cylindrical part, and is fixed to the cored bar so as to extend in the outer diameter direction. A seal lip that is in contact with or close to a non-fitting cylindrical portion whose tip is located on the outer diameter side;
A sealing device characterized in that a tip portion of the seal lip is configured to face toward the outer opening. The sealing device according to claim 1,
Between the first metal ring and the second metal ring, there is further provided a sub seal member parallel to the seal member along the axial direction,
The sub-seal member is provided on the inner opening side leading to the inside of the bearing device in the opening of the space from the seal member, and the sub-seal member includes the first non-fitting cylindrical part and A sub-core that is fitted to one of the second non-fitting cylindrical parts, and a sub that is fixed to the sub-core so as to extend in the radial direction and whose tip is in contact with or close to the other non-fitting cylindrical part A sealing device comprising a sealing lip. The sealing device according to claim 1 or 2,
The first non-fitting cylindrical portion and the second non-fitting cylindrical portion are configured to face each other in the radial direction. In the sealing device according to any one of claims 1 to 3,
The sealing device characterized in that the outer opening is configured to open in a radial direction. In the sealing device according to any one of claims 1 to 4,
The sealing device according to claim 1, wherein the first fitting cylindrical portion and the first non-fitting cylindrical portion of the first metal ring have different radial sizes. In the sealing device according to any one of claims 1 to 4,
The sealing device according to claim 1, wherein the first fitting cylindrical portion and the first non-fitting cylindrical portion in the first metal ring have the same radial size. In the sealing device according to any one of claims 1 to 6,
The sealing device, wherein the second fitting cylindrical portion and the second non-fitting cylindrical portion in the second metal ring have different radial sizes. In the sealing device according to any one of claims 1 to 6,
The sealing device according to claim 2, wherein the second fitting cylindrical portion and the second non-fitting cylindrical portion in the second metal ring have the same radial size.

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