JP2021099136A - Rotation seal - Google Patents

Abstract

To restrain deterioration of a seal performance, and easily discharge slurry and the like once entering a seal inner space, by further improving a watered performance of an axial lip.SOLUTION: A radial gap D between an outer periphery C1 of a joint member N jointed to a slinger 2 and an inner periphery E of a seal body 3 includes a first gap part D1 and a second gap part D2. A first outer periphery F1 of the joint member N forming the first gap part D1 has a cylindrical shape. The radial gap D at the first gap part D1 is almost constant in a direction parallel to an axial direction. A second outer periphery F2 of the joint member N forming the second gap part D2 has a conical shape whose diameter is reduced toward a core flange part 4B in the parallel direction. The radial gap D at the second gap part D2 is gradually increased toward the core flange part 4B in the parallel direction. A gap L3 in the parallel direction between a core flange part 4B side end J of the second outer periphery F2 and the seal body 3 is more than 1 mm.SELECTED DRAWING: Figure 2

Description

The present invention relates to a rotating seal used for a rotating shaft of a transportation machine or a general machine.

For example, as a rotating seal used for a rotating shaft of a bearing device for supporting an automobile wheel, a seal body composed of a core metal attached to an outer ring and a sealing member joined to the core metal, and a slinger attached to an inner ring. (See, for example, Patent Documents 1 and 2).

Since the axial lip of the sealing member (for example, the side lip 26a of Patent Document 1 and the side lip 621 of Patent Document 2) is located on the outermost air side of the sealing member, it can follow the infiltration of muddy water or the like. It may deteriorate and the sealing property may deteriorate.

Therefore, in the rotary seal, in order to suppress the intrusion of muddy water and the like, a minute gap having an L-shaped cross section is provided on the outer diameter side of the axial lip (for example, the labyrinth portion Lp of Patent Document 1 and the labyrinth portion Lp of Patent Document 1). See the labyrinth structure part r of Patent Document 2).

That is, the rotating seal (pack seal 10b) of FIG. 1 of Patent Document 1 is provided with a labyrinth portion Lp having an L-shaped cross section, which is composed of an axial labyrinth 1 Lp and a radial labyrinth 2 Lp. Similarly, in the rotation seal (bearing seal 11) of Patent Document 2, a labyrinth structure portion r having an L-shaped cross section including a first labyrinth portion r1 and a second labyrinth portion r2 is provided.

In Patent Document 2, the axial length d1 of the first labyrinth portion r1 along the axial direction is 1.5 mm or more, and the axial length d2 of the inner diameter side portion of the outer diameter side cylindrical portion of the first member 50 is 0. The gap a of the second labyrinth portion r2 is set to 75 mm or more and 1 mm or less.

Japanese Patent No. 5708204 Japanese Patent No. 6556488

Since the conventional rotary seal as described above has a minute gap having an L-shaped cross section on the outer side in the radial direction from the axial lip, it is difficult for muddy water or the like to enter due to the sealing function, and the axial lip is covered with water. It is considered difficult to do.

However, according to a test conducted by the inventors of the present application to actually observe the state of the radial gap of various rotary seals, when the conventional rotary seal is used in an environment where muddy water is applied, the edge of the radial gap is used. It was clarified that muddy water clings to the part, and the one on the inner space side of the seal of muddy water is scattered by the centrifugal force due to the rotation of the rotating shaft, and the axial lip may be exposed to water.

Even in the rotary seal having a labyrinth portion formed in an L-shaped cross section as in Patent Documents 1 and 2, since the minute gap is extended, muddy water is spread over the entire area of the minute gap due to the large surface tension of water. It is considered that the muddy water is present and clings to the end of the seal internal space side of the minute gap, and the muddy water clinging to the seal internal space side is scattered by centrifugal force.

Therefore, there is room for improvement in the conventional rotary seal from the viewpoint of further improving the water receiving performance of the axial lip and suppressing the deterioration of the seal performance.

Patent Document 2 states, "That is, in the experimental example of each sample, even if muddy water or the like enters the space 110 of each bearing seal 11, the shaft of the first member 50 accompanies the shaft rotation of the inner ring 5. It is understood that muddy water or the like is easily discharged to the outside (opposite side to the bearing space S) through the labyrinth structure r due to the centrifugal force and the pumping action due to the rotation. " However, the performance test of the rotary seal is carried out by "observing the bearing space S (see FIG. 1) side portion of each bearing seal", and the effect of discharging the infiltrated muddy water is not confirmed. In the performance tests of FIGS. 6 and 7 of Patent Document 2, the reason why the seal life of the example was longer than that of the comparative example was that the labyrinth portion of the comparative example had a straight cross section. It is considered that the labyrinth portion having an L-shaped cross section, which is an example (FIG. 2, FIG. 3 and FIG. 5 of Patent Document 2), is more difficult for muddy water and the like to infiltrate.

In the rotary seal having the labyrinth portion formed in the L-shaped cross section as in Patent Documents 1 and 2, since the cross section of the labyrinth portion is L-shaped, the inside of the seal is more than the one in which the cross section of the labyrinth portion is linear. It is considered that the structure is such that muddy water and the like do not easily enter the space. However, in the rotating seal in which the labyrinth portion is formed in an L-shaped cross section, once muddy water or the like has entered the space inside the seal, the labyrinth portion having an L-shaped cross section is present, so that the muddy water or the like is less likely to be discharged. When the muddy water in the seal internal space dries, mud accumulates in the seal internal space. The accumulated mud mixes with the grease, bites between the axial lip and the flange portion of the slinger where the axial lip is in sliding contact, and scrapes and wears the axial lip and the flange portion. As a result, there is a concern that it will not function as a seal.

Therefore, in view of the above-mentioned situation, the present invention tries to solve the problem by further improving the water receiving performance of the axial lip and suppressing the deterioration of the sealing performance, and at the same time, the rotation that makes it easy to discharge the muddy water or the like that has once entered the seal internal space. The point is to provide a seal for use.

The gist of the present invention is as follows.
[1]
A rotating seal including a core metal attached to the outer diameter side member, a seal body composed of a seal member joined to the core metal, and a slinger attached to the inner diameter side member.
The core metal is
The core metal cylindrical portion fitted inside the outer diameter side member, and the core metal flange portion extending from one end of the core metal cylindrical portion in a direction parallel to the axial direction of the inner diameter side member to the inner diameter side. Consists of
The slinger
The slinger cylindrical portion externally fitted to the inner diameter side member, the slinger flange portion extending from one end of the slinger cylindrical portion in a direction parallel to the axial direction to the outer diameter side, and the core from the outer diameter side end portion of the slinger flange portion. Slinger bent part bent toward the gold flange part, or
It consists of a slinger cylindrical portion that fits outside the inner diameter side member and a slinger flange portion that extends from one end of the slinger cylindrical portion in a direction parallel to the axial direction to the outer diameter side.
The seal member is
Includes an axial lip that slides into the slinger flange
The rotating seal is
The slinger flange portion and the slinger bent portion, or the slinger bent portion,
Alternatively, a joining member joined to the slinger flange portion is provided.
The radial gap between the inner peripheral surface of the seal body and the outer peripheral surface of the joining member is
The first gap portion far from the core metal flange portion and the second gap portion close to the core metal flange portion are included.
The first outer peripheral surface of the joining member forming the first gap is cylindrical or substantially cylindrical.
The radial gap in the first gap is substantially constant in the direction parallel to the axial direction.
The second outer peripheral surface of the joining member forming the second gap portion has a conical shape or a substantially conical shape that shrinks in diameter as it approaches the core metal flange portion in a direction parallel to the axial direction.
The radial gap in the second gap gradually increases as it approaches the core flange portion in a direction parallel to the axial direction.
The gap between the end of the second outer peripheral surface on the side of the core metal flange portion and the seal body in the direction parallel to the axial direction is larger than 1 mm.
Rotating seal.

[2]
The joining member is an encoder member, a synthetic resin member, or a synthetic rubber member.
The rotating seal according to [1].

[3]
A rotating seal including a core metal attached to the outer diameter side member, a seal body composed of a seal member joined to the core metal, and a slinger attached to the inner diameter side member.
The core metal is
The core metal cylindrical portion fitted inside the outer diameter side member, and the core metal flange portion extending from one end of the core metal cylindrical portion in a direction parallel to the axial direction of the inner diameter side member to the inner diameter side. Consists of
The slinger
The slinger cylindrical portion externally fitted to the inner diameter side member, the slinger flange portion extending from one end of the slinger cylindrical portion in a direction parallel to the axial direction to the outer diameter side, and the core from the outer diameter side end portion of the slinger flange portion. It consists of a slinger bend that bends toward the gold flange.
The seal member is
Includes an axial lip that slides into the slinger flange
The radial gap between the inner peripheral surface of the seal body and the outer peripheral surface of the slinger bent portion is
The first gap portion far from the core metal flange portion and the second gap portion close to the core metal flange portion are included.
The first outer peripheral surface of the slinger bent portion forming the first gap portion is cylindrical or substantially cylindrical.
The radial gap in the first gap is substantially constant in the direction parallel to the axial direction.
The second outer peripheral surface of the slinger bent portion forming the second gap portion has a conical shape or a substantially conical shape that shrinks in diameter as it approaches the core metal flange portion in a direction parallel to the axial direction.
The radial gap in the second gap gradually increases as it approaches the core flange portion in a direction parallel to the axial direction.
The gap between the end of the second outer peripheral surface on the side of the core metal flange portion and the seal body in the direction parallel to the axial direction is larger than 1 mm.
Rotating seal.

[4]
The radial length H at the farthest end from the core metal flange portion in the first gap portion is
0.3 mm ≤ H ≤ 1.0 mm,
The length L1 of the first gap portion in the direction parallel to the axial direction and the length L2 of the second gap portion in the direction parallel to the axial direction are in the direction parallel to the axial direction of the rotation seal. Let the length be L
L1 / L ≧ 0.2, L2 / L ≧ 0.2, and
(L1 + L2) / L ≦ 0.8,
The inclination angle IA of the tangent line of the end of the second outer peripheral surface on the side end of the core metal flange portion with respect to the inner peripheral surface of the seal body is
5 ° ≤ IA ≤ 30 °,
The rotating seal according to any one of [1] to [3].

According to such a configuration of the rotating seal, the radial gap between the inner peripheral surface of the seal body and the outer peripheral surface of the joining member is formed in the first gap portion far from the core metal flange portion and the core metal flange portion. The radial gap in the first gap is substantially constant in the direction parallel to the axial direction, including the second gap close to the second gap, and the radial gap in the second gap is in the direction parallel to the axial direction. The muddy water that gradually increases as it approaches the core metal flange portion and first enters the radial gap from the outside air side is held in the radial gap by the surface tension of the water.

Here, the "first infiltrated muddy water" is the muddy water that infiltrated at the initial stage when the rotating seal was in a water-covered state. When released from the water-covered state or when the water-covered amount decreases, the water film disappears due to scattering, evaporation, etc. When the rotating seal becomes water-covered again, the muddy water initially infiltrated at that time is held in the radial gap by the surface tension of the water.

Therefore, by holding the muddy water in the radial gap by the surface tension of the water, it is possible to prevent the muddy water from entering the bearing.

Further, in the second gap portion, the radial gap gradually increases as it approaches the core metal flange portion in a direction parallel to the axial direction. Since the second gap portion having such a shape is provided, even water having a large surface tension does not cling to the seal internal space side end portion of the radial gap and is held in the radial gap. The end of the muddy water on the inner space side of the seal is located on the outside air side of the end of the outer peripheral surface of the joining member on the inner space side of the seal.

Therefore, even if a centrifugal force that rotates the inner diameter side member acts on the muddy water held in the radial gap, the muddy water does not scatter in the space inside the seal, so that the water receiving performance of the axial lip is further improved and the sealing performance is improved. The decrease can be suppressed.

Furthermore, since it is a simple structure without having a complicated labyrinth structure, it is possible to suppress an increase in manufacturing cost.

Further, even if the muddy water held in the radial gap is destroyed by disturbance or the like and the muddy water or the like infiltrates into the seal internal space, the core metal flange portion side end of the second outer peripheral surface of the joining member and the seal body Since the gap in the direction parallel to the axial direction is larger than 1 mm and the radial labyrinth is not formed, muddy water or the like that has entered the seal internal space is easily discharged. As a result, no muddy water remains in the space inside the seal, and the muddy water does not dry out and mud does not accumulate.

Therefore, the accumulated mud does not mix with the grease and get caught between the axial lip and the flange portion of the slinger where the axial lip is in sliding contact. As a result, there is no concern that the axial lip and the flange portion will be scraped and worn, and thus the function as a seal will not be fulfilled.

As described above, according to the rotating seal according to the present invention, the following effects are obtained.
(1) By holding the muddy water in the radial gap by the surface tension of the water, it is possible to prevent the muddy water from entering the bearing.
(2) Even if a centrifugal force that rotates the inner diameter side member acts on the muddy water held in the radial gap by the surface tension of the water, the muddy water does not scatter in the space inside the seal, so that the water receiving performance of the axial lip is improved. It can be enhanced to suppress deterioration of sealing performance.
(3) Since the structure is simple without providing a complicated labyrinth structure, an increase in manufacturing cost can be suppressed.
(4) Even if the muddy water held in the radial gap is destroyed by disturbance or the like and the muddy water or the like invades the seal internal space, the radial labyrinth is not formed, so the muddy water or the like that has entered the seal internal space is discharged. It becomes easy to be done.
(5) As a result, mud does not accumulate in the internal space of the seal, and there is no concern that the mud will get caught and the axial lip and the slinger flange portion will be worn and will not function as the seal.

It is a schematic partial cross-sectional view which shows the example which used the rotary seal which concerns on embodiment of this invention in the bearing device for wheel support of an automobile. It is an enlarged view of the main part of FIG. 1 which shows the circumference of the rotating seal. It is sectional drawing corresponding to FIG. 2 which shows the modification of the rotary seal. It is sectional drawing corresponding to FIG. 2 which shows another modification of the said rotary seal. It is sectional drawing corresponding to FIG. 2 which shows still another modification of the said rotary seal. 2 is a cross-sectional view corresponding to FIGS. 2 and 3 showing a conventional shape rotating seal. 2 is a cross-sectional view corresponding to FIGS. 2 and 3 showing another conventional shape of a rotating seal. FIG. 5 is an enlarged cross-sectional view of a main part showing a state in which a rotary seal having the conventional shape of FIG. 4 is attached to a test jig imitating a bearing device for supporting an automobile wheel. FIG. 5 is an enlarged cross-sectional view of a main part showing a state in which a rotary seal having the conventional shape of FIG. 5 is attached to a test jig imitating a bearing device for supporting an automobile wheel. FIG. 5 is an enlarged cross-sectional view of a main part showing a state in which a rotation seal according to an embodiment of the present invention having the shape of FIG. 2 is attached to a test jig imitating a bearing device for supporting an automobile wheel.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.

In the present specification, the direction of the rotation axis (reference numeral O in FIG. 1) of the inner diameter side member, which is the rotation side member, is defined as the "axial direction" in the state where the rotation seal is attached to the inner diameter side member and the outer diameter side member. (Reference P in FIG. 1). The direction orthogonal to the axial direction is called the "diameter direction".

Further, in a bearing device for supporting a wheel of an automobile, the direction from the vehicle body of the automobile toward the wheel side is referred to as "outward", and the opposite direction is referred to as "inward".

In the inner diameter side member and the outer diameter side member to which the rotation seal of the present invention is mounted, these are coaxial, but the case where their axes are displaced in parallel (when there is a center deviation) is also included. ..

<Bearing device>
The cross-sectional view of FIG. 1 shows an example in which the rotary seal 1 according to the embodiment of the present invention is used inside the bearing device 11 for supporting a wheel of an automobile.

The bearing device 11 has an inner ring 7 which is an inner ring side member A that rotates with the wheels and an inner ring raceway surface 7A formed on the outer peripheral surface, and an outer diameter side integrated with the vehicle body having an outer ring raceway surface 8A formed on the inner peripheral surface. The bearing includes an outer ring 8 which is a member B, and balls 9, 9, ... Which are rolling elements that roll between the inner ring raceway surface 7A and the outer ring raceway surface 8A.

Further, the bearing device 11 has an inner and outer end portion between the inner ring 7 and the outer ring 8 of the bearing (inner side of the inner ball 9, ... And outer side of the outer ball 9, ...). ) Is provided with rotating seals 1 and 10 to prevent the ingress of muddy water and the like and to prevent the leakage of lubricating grease. Further, the bearing device 11 includes an encoder device that detects the rotation speed (rotational speed) of the wheels.

<Inner rotation seal>
As shown in the cross-sectional view of FIG. 2, the inner rotating seal 1 of the bearing device 11 according to the embodiment of the present invention is joined to the core metal 4 mounted on the outer ring 8 and the core metal 4. A seal body 3 made of a seal member 5 and a slinger 2 mounted on an inner ring 7 are provided. Here, the inner peripheral surface E of the seal body 3 composed of the core metal 4 and the seal member 5 is a substantially cylindrical surface.

In the rotating seal 1 shown in FIG. 2, the seal thickness (length in the direction parallel to the axial direction P (FIG. 1)) L is 3.5 mm ≦ L ≦ 7 mm, and the width of the seal (length in the radial direction). ) M is 5 mm ≦ M ≦ 9 mm.

The core metal 4 is formed from one end (outer side end portion) in the direction parallel to the axial direction P of the core metal cylindrical portion 4A and the core metal cylindrical portion 4A that are internally fitted in the outer ring 8 to the inner diameter side (inward in the radial direction). It is composed of an extending core metal flange portion 4B. The core metal 4 is manufactured from, for example, a stainless steel plate by pressing.

The slinger 2 is a slinger flange extending from one end (inner side end) in a direction parallel to the axial direction P of the slinger cylindrical portion 2A and the slinger cylindrical portion 2A that are externally fitted to the inner ring 7 to the outer diameter side (diametrically outward). It is composed of a slinger bent portion 2C bent from the outer diameter side end portion of the slinger flange portion 2B and the slinger flange portion 2B toward the core metal flange portion 4B. The shape of the slinger bent portion 2C in FIG. 2 is cylindrical. The slinger 2 is manufactured from, for example, a stainless steel plate by pressing.

A joining member N is joined to the slinger flange portion 2B and the slinger bent portion 2C. The joining member N is an encoder member 6 such as a rubber magnet or a plastic magnet that constitutes the encoder device. A sensor (not shown) constituting the encoder device is located inside the encoder member 6, and the sensor faces the encoder member 6 from a direction parallel to the axial direction P.

The sealing member 5 is synthetic rubber, and the base 5A thereof is vulcanized and adhered to the core metal 4. The sealing member 5 includes an axial lip 5B extending from the base 5A and sliding in contact with the vertical surface 2D of the slinger flange portion 2B, and a lip structure including a radial lip 5C and a grease lip 5D sliding in contact with the outer peripheral surface of the slinger cylindrical portion 2A. .. Further, the sealing member 5 has an outer peripheral sealing portion 5E that covers the tip (inner side end portion) of the core metal cylindrical portion 4A, and the outer peripheral sealing portion 5E is a substrate 5A from the inner peripheral surface side of the core metal cylindrical portion 4A. It leads to.

As the synthetic rubber material forming the seal member 5, as a rubber material having good oil resistance, nitrile rubber (NBR), hydride nitrile rubber (HNBR), acrylic rubber (ACM), ethylene / acrylic rubber (AEM), fluorine From rubbers such as rubber (FKM, FPM) and silicone rubber (VQM), one type or two or more types of rubber can be appropriately blended and used. Considering the kneading processability, vulcanization formability, and adhesion to the core metal 3 of the rubber material, other types of rubber such as liquid NBR, ethylene propylene rubber (EPDM), natural rubber (NR), and isoprene It is also a preferable embodiment to use it by blending it with rubber (IR), styrene-butadiene rubber (SBR), butadiene rubber (BR) or the like.

As shown in the cross-sectional view of FIG. 2, the radial gap D between the outer peripheral surface C1 of the joining member N joined to the slinger flange portion 2B and the slinger bent portion 2C and the inner peripheral surface E of the seal body 3 is a core. It includes a first gap D1 far from the gold flange 4B (inner) and a second gap D2 close to the core flange 4B (outer).

The first outer peripheral surface F1 of the joining member N forming the first gap D1 is cylindrical, and the radial gap D in the first gap D1 is substantially constant in the direction parallel to the axial direction P.

The second outer peripheral surface F2 of the joining member N forming the second gap D2 has a conical shape that shrinks in the direction parallel to the axial direction P as it approaches the core metal flange 4B, and is formed in the second gap D2. The radial gap D gradually increases as it approaches the core metal flange portion 4B in the direction parallel to the axial direction P.

The gap L3 in the direction parallel to the axial direction P between the core metal flange portion 4B side end J of the second outer peripheral surface F2 and the seal body 3 is larger than 1 mm (L3> 1 mm). As a result, no radial labyrinth is formed.

The surface tension of water (72.75 mN / m at 20 ° C.) is the surface tension of many other liquids (eg, at 20 ° C., 23.30 mN / m for acetone, 22.55 mN / m for ethanol, 22. Since it is larger than 60 mN / m), water tends to cling to the radial gap D.

When water, for example, muddy water G clings to the radial gap D in this way, the radial gap D is provided so that the one on the seal internal space S side of the muddy water G does not scatter due to the centrifugal force due to the rotation of the inner ring 7. The shape of the outer peripheral surface C1 (first outer peripheral surface F1 and second outer peripheral surface F2) of the joining member N is set so as to provide the first gap portion D1 and the second gap portion D2.

That is, as described above, the second outer peripheral surface F2 of the joining member N forming the second gap D2 has a conical shape that shrinks in diameter as it approaches the core metal flange portion 4B in the direction parallel to the axial direction P. As a result, the radial gap D in the second gap D2 gradually increases as it approaches the core metal flange portion 4B in the direction parallel to the axial direction P.

Since the second gap D2 having such a shape is provided, even water having a large surface tension does not cling to the seal internal space S side end of the radial gap D, and the radial gap D is provided. As shown in FIG. 2, the end portion of the held muddy water G on the seal internal space S side is the core metal flange portion 4B side end (seal internal space S) of the outer peripheral surface C1 (second outer peripheral surface F2) of the joining member N. Side end) It will be located on the outside air side of J.

Therefore, even if the centrifugal force that rotates the inner ring 7 which is the inner diameter side member A that rotates with the wheel acts on the muddy water G held in the radial gap D, the muddy water G does not scatter in the seal internal space S, so that it is axial. It is possible to further improve the water receiving performance of the lip 5B and suppress the deterioration of the sealing performance.

<Modification example>
The first outer peripheral surface F1 of the joining member N forming the first gap D1 may have an arc shape (a substantially cylindrical shape close to a cylinder) instead of a cylindrical shape. Further, the second outer peripheral surface F2 of the joining member N forming the second gap D2 may have an arc shape (a substantially conical shape close to a cone) instead of a conical shape.

That is, in the outer peripheral surface C1 of the joining member N, the first outer peripheral surface F1 is made cylindrical or substantially cylindrical, and the second outer peripheral surface F2 becomes closer to the core metal flange portion 4B in the direction parallel to the axial direction P. Make it a conical or substantially conical shape with a reduced diameter.

The shape of the slinger bent portion 2C is not limited to the cylindrical shape as shown in the cross-sectional view of FIG. 2, but may be a truncated cone cylinder shape or the like as shown in the cross-sectional view of FIG. Alternatively, as shown in the cross-sectional view of FIG. 4, the slinger bent portion 2C may be eliminated.

The joining member N is not limited to the encoder member 6, and if the function as the encoder device is not required depending on the location where the rotary seal 1 is used, the joint member N is replaced with a synthetic resin member. Alternatively, a synthetic rubber member may be used.

When the joining member N is an encoder member 6, the joining member N is joined to the slinger flange portion 2B and the slinger bent portion 2C, or the slinger flange portion 2B. When the joining member N is not the encoder member 6, the joining member N is joined to the slinger flange portion 2B and the slinger bent portion 2C, the slinger bent portion 2C, or the slinger flange portion 2B.

The cross-sectional view of FIG. 5 shows an example in which the joint member N is eliminated and the radial gap D similar to that of FIGS. 2 to 4 is formed on the outer peripheral surface C2 of the slinger bent portion 2C.

That is, the radial gap D between the inner peripheral surface E of the seal body 3 and the outer peripheral surface C2 of the slinger bent portion 2C is the first gap D1 far from the core metal flange portion 4B and the core. Includes the (outer) second gap D2 close to the gold flange 4B. The first outer peripheral surface F1 of the slinger bent portion 2C forming the first gap portion D1 is cylindrical or substantially cylindrical, and the radial gap D in the first gap portion D1 is in a direction parallel to the axial direction P. Is almost constant. Further, the second outer peripheral surface F2 of the slinger bent portion 2C forming the second gap portion D2 has a conical shape or a substantially conical shape that shrinks in the direction parallel to the axial direction P as it approaches the core metal flange portion 4B. The radial gap D in the second gap D2 gradually increases as it approaches the core metal flange portion 4B in the direction parallel to the axial direction P.

Further, the gap L3 in the direction parallel to the axial direction P between the core metal flange portion 4B side end J of the second outer peripheral surface F2 and the seal body 3 is larger than 1 mm (L3> 1 mm). As a result, no radial labyrinth is formed.

Next, the numerical ranges of the specifications L1, L2, IA, and H shown in FIGS. 2 to 5 will be described.

Let L be the length of the rotation seal 1 in the direction parallel to the axial direction P. The length L1 of the first gap D1 in the direction parallel to the axial direction P is set to L1 / L ≧ 0.2 based on the test results described later. This is to keep the water film stable due to the surface tension of water.

The length L2 of the second gap D2 in the direction parallel to the axial direction P is set to L2 / L ≧ 0.2 based on the test results described later. This is because the muddy water G is collected in the first gap D1 by centrifugal force.

Further, (L1 + L2) / L ≦ 0.8 is set. This is to prevent interference with the seal body 3.

The inclination angle IA of the conical second outer peripheral surface F2, which is the alternate long and short dash line of FIGS. 2 to 5, with respect to the inner peripheral surface E of the seal body 3 is 5 ° ≤ IA ≤ 30 °, and 10 ° ≤ IA ≤ 25. It is more preferably °. It is the range of the inclination angle IA in which the muddy water G can be collected in the first gap D1 by centrifugal force.

When the second outer peripheral surface F2 has an arc shape instead of a conical shape, the inclination angle IA is the tangent line of the end of the core metal flange portion 4B side of the second outer peripheral surface F2 with respect to the inner peripheral surface E of the seal body 3. The tilt angle.

The radial length H of the farthest end from the core metal flange portion 4B in the first gap portion D1 is 0.3 mm ≦ H ≦ 1.0 mm, and more preferably 0.3 mm ≦ H ≦ 0.5 mm. The reason why H ≧ 0.3 mm is to eliminate the interference between the seal body 3 and the joining member N due to the eccentricity under load, and the reason why H ≦ 1.0 mm is to stabilize the water film by the surface tension of water. This is to hold.

<Diameter gap observation test>
(1) Test for determining the dimension of the length L1 of FIGS. 2 to 5

L = 5 mm, H = 0.4 mm in the rotary seal 1A in the cross-sectional view of FIG. 6 and the rotary seal 1B in the cross-sectional view of FIG. 7, which are conventional rotary seals that do not form a radial labyrinth as in the present invention. Is common. Table 1 shows the length L4 of the rotational seal 1A in the direction parallel to the axial direction P of the radial gap D and the length L5 of the rotational seal 1B in the direction parallel to the axial direction P of the radial gap D. Compare the specifications.

(Test method)
The test jig 12 shown in the cross-sectional views of FIGS. 8A and 8B, which imitates a bearing device for supporting an automobile wheel as shown in the cross-sectional view of FIG. 1, is used. The rotation seal 1A is attached to the test jig 12 as shown in FIG. 8A, and the rotation seal 1B is attached to the test jig 12 as shown in FIG. 8B. The dummy outer ring 14, which is the outer diameter side member B into which the core metal 4 is fitted, is attached at a position eccentric by 0.1 mm from the axial center by TIR (Total Indicator Reading).

The test jig 12 of FIG. 8A equipped with the rotation seal 1A and the test jig 12 of FIG. 8B equipped with the rotation seal 1B were manufactured one by one, and the axis of each test jig 12 was horizontal. Muddy water having a water temperature of 23 ° C. mixed with 10% by weight of mud (Kanto loam powder) is charged to the position of the axis of each test jig 12.

In that state, the dummy inner ring 13 which is the inner diameter side member A is rotated with respect to the dummy outer ring 14 which is the outer diameter side member B at a rotation speed of 1500 rpm for 1 hour, and FIGS. The behavior of muddy water is confirmed by observing the radial gap D on the seal internal space S side in the rotating seals 1A and 1B from the hole made at the observation position K.

(Test results)
From the test results shown in Table 1, if the length (L4, L5) of the radial gap D in the direction parallel to the axial direction is 1 mm or more (the ratio to L is 0.2 or more), the muddy water G is surfaced. It can be seen that the tension can temporarily hold the radial gap D. Further, even if the length of the radial gap D in the direction parallel to the axial direction P is sufficiently long (L5 = 3.2 mm), the result is that the length of the radial gap D in the direction parallel to the axial direction P is. It was similar to the short L4 = 1.0 mm.

From the above test results, in the rotation seal 1 shown in FIGS. 2 to 5, the length L1 in the direction parallel to the axial direction P of the first gap D1 has a ratio of 0.2 or more to L (L1 / L). ≧ 0.2).

(2) Test for determining the dimension of the length L2 of FIGS. 2 to 5

Next, in the rotation seal 1 shown in FIG. 2, the muddy water G is held in the radial gap D by surface tension with L1 / L ≧ 0.2, and then the muddy water G is kept in the seal internal space even when centrifugal force acts. In order not to scatter into S, the test is performed by changing the length L2 in the direction parallel to the axial direction P of the second gap D2.

In the rotation seal 1 shown in FIG. 2, L = 5 mm, H = 0.4 mm, L1 = 1.5 mm, L1 / L = 0.3, and IA = 15 ° are common, and the directions are parallel to the axial direction P. For the length L2, the specifications shown in Table 2 (Comparative Example 1, Example 1, Example 2) are compared.

(Test method)
A test jig 12 shown in an enlarged vertical cross-sectional view of a main part of FIG. 8C, which imitates a bearing device for supporting an automobile wheel as shown in FIG. 1, is used. As shown in FIG. 8C, the dummy outer ring 14 which is the outer diameter side member B in which the rotation seal 1 is attached to the test jig 12 and the core metal 4 is fitted is 0 in TIR (Total Indicator Reading) from the axis. Install in a position eccentric by 1 mm.

One test jig 12 equipped with a rotation seal 1 having a different length L2 in the direction parallel to the axial direction P was manufactured, the axis of each test jig 12 was horizontal, and 10% by weight of mud. Muddy water having a water temperature of 23 ° C. mixed with (Kanto loam powder) is poured up to the position of the axis of each test jig 12.

In that state, the dummy inner ring 13 which is the inner diameter side member A is rotated with respect to the dummy outer ring 14 which is the outer diameter side member B at a rotation speed of 1500 rpm for 1 hour, and a hole is made at the observation position K in FIGS. 2 and 8C. Therefore, the behavior of muddy water is confirmed by observing the radial gap D on the seal internal space S side of the rotating seal 1.

(Test results)
As shown in the test results shown in Table 2, in Comparative Example 1 (L2 = 0.75 mm, L2 / L = 0.15), the effect of the second gap D2 was not observed, and the muddy water G was the rotation of the dummy inner ring 13. It was scattered in the seal internal space S due to the centrifugal force caused by.

On the other hand, in Example 1 (L2 = 1.0 mm, L2 / L = 0.2) and Example 2 (L2 = 1.7 mm, L2 / L = 0.34), the muddy water G shown in FIG. 2 As described above, the muddy water G does not protrude toward the seal internal space S side from the joining member N, and the end portion of the muddy water G held in the radial gap D by the large surface tension of water on the seal internal space S side is joined. The outer peripheral surface C1 (conical second outer peripheral surface F2) of the member N was located on the outside air side of the inward flange portion 4B side end J.

From the above test results, in the rotation seal 1 shown in FIGS. 2 to 5, the length L2 of the second gap D2 in the direction parallel to the axial direction P is L2 / L ≧ 0.2.

<Muddy water inundation test>
(Examples and comparative examples)
Examples are Example 2 (L1 = 1.5 mm, L1 / L = 0.3, L2 = 1.7 mm, L2 / L = 0.34) in Table 2. As a comparative example, L4 = 1.5 mm (L4 / L = 0.3) in Table 1 is referred to as Comparative Example 2, and L5 = 3.2 mm (L5 / L = 0.64) in Table 1 is referred to as Comparative Example 3.

(Test method)
An outer diameter in which the rotation seals 1, 1A and 1B of Example 2, Comparative Example 2 and Comparative Example 3 are attached to a bearing device for supporting a wheel of an automobile as shown in FIG. 1, and a core metal 4 is fitted. The outer ring 8 which is the side member B is attached at a position eccentric by 0.1 mm from the axial center by TIR (Total Indicator Reading).

Two bearing devices equipped with the rotation seal 1 of Example 2, the bearing device equipped with the rotation seal 1A of Comparative Example 2, and the bearing device equipped with the rotation seal 1B of Comparative Example 3. Each bearing device is manufactured one by one, the axis of each bearing device is horizontal, and muddy water having a water temperature of 23 ° C. mixed with 10% by weight of mud (Kanto loam powder) is charged to the position of the axis of each bearing device.

In that state, the inner ring 7 which is the inner diameter side member A is rotated with respect to the outer ring 8 which is the outer diameter side member B at a rotation speed of 1500 rpm, and whether there is a leak in the bearing inner T (for example, see FIG. 2) every day. Observe whether or not.

(Test results)
In Comparative Example 2, in the two bearing devices, muddy water began to leak into the bearing internal T 11 days and 7 days after the start of the test.

In Comparative Example 3, in the two bearing devices, muddy water began to leak into the bearing internal T 14 days and 12 days after the start of the test.

On the other hand, in Example 2, since there was no leakage of muddy water in the bearing internal T 25 days after the start of the test in the two bearing devices, the test was terminated 25 days after the start of the test.

From the above test results, it can be seen that the rotary seal 1 according to the embodiment of the present invention has very high sealing performance.

In the rotation seal 1 of FIGS. 2 to 5, even if the muddy water G held in the radial gap D is destroyed by disturbance or the like and the muddy water or the like infiltrates into the seal internal space S, the second outer peripheral surface of the joining member N Since the gap L3 in the direction parallel to the axial direction P between the core metal flange side 4B end J of F2 and the seal body 3 is larger than 1 mm and no radial labyrinth is formed, muddy water that has entered the seal internal space S. Etc. are easily discharged. As a result, the muddy water G does not remain in the seal internal space S, and the muddy water G does not dry out and mud does not accumulate.

Therefore, the accumulated mud does not mix with the grease and get caught between the slinger flange portion 2B where the axial lip 5B and the axial lip 5B are in sliding contact with each other. As a result, there is no concern that the axial lip 5B and the slinger flange portion 2B will be scraped and worn, and thus the function as a seal will not be achieved.

The above description of the embodiments are all examples, and the present invention is not limited thereto. Various improvements and modifications can be made without departing from the scope of the present invention.

1,1A, 1B Rotating seal 2 Slinger 2A Slinger cylindrical part 2B Slinger flange part 2C Slinger bent part 2D Vertical surface 3 Seal body 4 Core metal 4A Core metal cylindrical part 4B Core metal flange part 5 Sealing member 5A Base 5B Axial lip 5C Radial Lip 5D Grease Lip 5E Outer Seal 6 Encoder Member 7 Inner Ring 7A Track Surface 8 Outer Ring 8A Track Surface 9 Balls (Rolling Body)
10 Rotating seal 11 Bearing device 12 Test jig 13 Dummy inner ring 14 Dummy outer ring A Inner diameter side member B Outer diameter side member C1 Outer surface surface of joining member C2 Outer surface surface of slinger bent part D Radial gap D1 First gap part D2 2nd gap E Inner peripheral surface F1 1st outer peripheral surface F2 2nd outer peripheral surface G Muddy water H Radial length of the farthest end from the core metal flange in the 1st gap IA Inclination angle J 2nd outer peripheral surface core metal Flange side end K Observation position L Length in the direction parallel to the axial direction of the rotating seal L1 Length in the direction parallel to the axial direction of the first gap L2 Length in the direction parallel to the axial direction of the second gap L3 Gap in the direction parallel to the axial direction between the end of the core metal flange portion of the second outer peripheral surface and the seal body L4, L5 Length in the direction parallel to the axial direction of the radial gap M Width (diameter) of the rotating seal Directional length) N Joint member O Rotating shaft P Axial direction S Seal internal space T Inside bearing

Claims (4)

A rotating seal including a core metal attached to the outer diameter side member, a seal body composed of a seal member joined to the core metal, and a slinger attached to the inner diameter side member.
The core metal is
The core metal cylindrical portion fitted inside the outer diameter side member, and the core metal flange portion extending from one end of the core metal cylindrical portion in a direction parallel to the axial direction of the inner diameter side member to the inner diameter side. Consists of
The slinger
The slinger cylindrical portion externally fitted to the inner diameter side member, the slinger flange portion extending from one end of the slinger cylindrical portion in a direction parallel to the axial direction to the outer diameter side, and the core from the outer diameter side end portion of the slinger flange portion. Slinger bent part bent toward the gold flange part, or
It consists of a slinger cylindrical portion that fits outside the inner diameter side member and a slinger flange portion that extends from one end of the slinger cylindrical portion in a direction parallel to the axial direction to the outer diameter side.
The seal member is
Includes an axial lip that slides into the slinger flange
The rotating seal is
The slinger flange portion and the slinger bent portion, or the slinger bent portion,
Alternatively, a joining member joined to the slinger flange portion is provided.
The radial gap between the inner peripheral surface of the seal body and the outer peripheral surface of the joining member is
The first gap portion far from the core metal flange portion and the second gap portion close to the core metal flange portion are included.
The first outer peripheral surface of the joining member forming the first gap is cylindrical or substantially cylindrical.
The radial gap in the first gap is substantially constant in the direction parallel to the axial direction.
The second outer peripheral surface of the joining member forming the second gap portion has a conical shape or a substantially conical shape that shrinks in diameter as it approaches the core metal flange portion in a direction parallel to the axial direction.
The radial gap in the second gap gradually increases as it approaches the core flange portion in a direction parallel to the axial direction.
The gap between the core metal flange side end of the second outer peripheral surface and the seal body in the direction parallel to the axial direction is larger than 1 mm.
Rotating seal. The joining member is an encoder member, a synthetic resin member, or a synthetic rubber member.
The rotating seal according to claim 1. A rotating seal including a core metal attached to the outer diameter side member, a seal body composed of a seal member joined to the core metal, and a slinger attached to the inner diameter side member.
The core metal is
The core metal cylindrical portion fitted inside the outer diameter side member, and the core metal flange portion extending from one end of the core metal cylindrical portion in a direction parallel to the axial direction of the inner diameter side member to the inner diameter side. Consists of
The slinger
The slinger cylindrical portion externally fitted to the inner diameter side member, the slinger flange portion extending from one end of the slinger cylindrical portion in a direction parallel to the axial direction to the outer diameter side, and the core from the outer diameter side end portion of the slinger flange portion. It consists of a slinger bend that bends toward the gold flange.
The seal member is
Includes an axial lip that slides into the slinger flange
The radial gap between the inner peripheral surface of the seal body and the outer peripheral surface of the slinger bent portion is
The first gap portion far from the core metal flange portion and the second gap portion close to the core metal flange portion are included.
The first outer peripheral surface of the slinger bent portion forming the first gap portion is cylindrical or substantially cylindrical.
The radial gap in the first gap is substantially constant in the direction parallel to the axial direction.
The second outer peripheral surface of the slinger bent portion forming the second gap portion has a conical shape or a substantially conical shape that shrinks in diameter as it approaches the core metal flange portion in a direction parallel to the axial direction.
The radial gap in the second gap gradually increases as it approaches the core flange portion in a direction parallel to the axial direction.
The gap between the core metal flange side end of the second outer peripheral surface and the seal body in the direction parallel to the axial direction is larger than 1 mm.
Rotating seal. The radial length H at the farthest end from the core metal flange portion in the first gap portion is
0.3 mm ≤ H ≤ 1.0 mm,
The length L1 of the first gap portion in the direction parallel to the axial direction and the length L2 of the second gap portion in the direction parallel to the axial direction are in the direction parallel to the axial direction of the rotation seal. Let the length be L
L1 / L ≧ 0.2, L2 / L ≧ 0.2, and
(L1 + L2) / L ≦ 0.8,
The inclination angle IA of the tangent line of the end of the second outer peripheral surface on the core metal flange side with respect to the inner peripheral surface of the seal body is
5 ° ≤ IA ≤ 30 °,
The rotating seal according to any one of claims 1 to 3.

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