JP2019190603A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device capable of reducing sliding torque, extending the life of sealing performance, and suppressing foreign matter from entering from the atmosphere side. In a sealing device (4) for sealing between a housing (3) and a rotating member (7) inserted through an insertion hole (30) provided in the housing, a cored bar (5) fitted in the housing and the cored bar. And a seal portion 8 fixed to the first lip, and the seal portion is disposed on the atmosphere side with respect to the first lip 80 for sealing the fluid to be sealed, and is disposed from the atmosphere side. And an annular second lip 81 that extends toward the rotating member while suppressing the entry of foreign matter, and the second lip has a predetermined gap H with respect to the peripheral surface 7a of the rotating member. A cylindrical portion 80a facing the circumferential surface of the rotating member is formed in this state, and the axial length L of the cylindrical portion is formed to be greater than or equal to the gap. [Selection diagram] Figure 1

Description

  The present invention relates to a sealing device that seals between a housing and a rotating member inserted through a shaft hole provided in the housing.

  The sealing device as described above includes a lip that slides on the rotating member in order to prevent leakage of a fluid to be sealed such as oil from a gap formed between the housing and the rotating member. When foreign matter such as dust enters the sliding portion of the lip with respect to the rotating member, the foreign matter bites into the sliding portion, lip wear is promoted, and oil leakage occurs. Also, in the case of a sealing device having a plurality of lips, when negative pressure is applied between the lips, the lips stick to the peripheral surface of the rotating member, generating frictional heat, increasing sliding torque, reducing sealing performance and durability, etc. Various problems arise.

The following Patent Document 1 relates to an oil seal provided with a main lip that prevents oil leakage and a dust lip that prevents foreign matter from entering the outside of the main lip, between the dust lip and the peripheral surface of the rotating shaft. A device having a minute gap is disclosed.
Patent Document 2 below relates to a sealing device having two lips as in Patent Document 1 below, and a plurality of annular protrusions are provided in the axial direction on the outer diameter surface of the lip end of a sub lip corresponding to a dust lip. Have been disclosed.

Japanese Utility Model Publication No. 62-172858 JP 2009-257485 A

  In Patent Document 1 and Patent Document 2, since a gap is formed between the dust lip and the rotating member, sticking of the dust lip to the peripheral surface of the rotating member is prevented, but this sticking is prevented. It cannot be said that it is possible to sufficiently prevent foreign matter from entering through the gap and causing biting.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sealing device that can reduce sliding torque and extend the life of sealing performance, and can suppress entry of foreign matter from the atmosphere side.

  A sealing device according to the present invention is a sealing device that seals between a housing and a rotating member that is inserted into an insertion hole provided in the housing, and an annular first lip for sealing a fluid to be sealed; An annular second lip that is disposed on the atmosphere side with respect to the first lip to suppress entry of foreign matter from the atmosphere side and extends toward the rotating member, and the second lip is A cylindrical portion facing the circumferential surface of the rotating member is formed with a predetermined gap with respect to the circumferential surface of the rotating member, and the axial length of the cylindrical portion is greater than or equal to the gap. It is formed.

  Since the sealing device according to the present invention has the above-described configuration, the sliding torque can be reduced and the life of the sealing performance can be extended, and the entry of foreign matters from the atmosphere side can be suppressed.

It is 1st Embodiment of the sealing device which concerns on this invention, Comprising: It is a partially broken longitudinal cross-sectional view which shows typically the state with which the sealing device was mounted | worn as an oil seal. FIG. 2 is a partially broken longitudinal sectional view schematically showing a partially enlarged state in which the sealing device according to the embodiment is mounted on a mounting target (partial enlarged view of FIG. 1). (A) And (b) is a figure which shows the modification of the sealing device which concerns on the same embodiment, and is a partially broken longitudinal cross-sectional view which expands partially and shows typically the state with which the mounting object was mounted | worn. (A) And (b) is a figure which shows the further modification of the sealing device which concerns on the embodiment, and is a partial fracture longitudinal cross-sectional view which expands partially and shows typically the state mounted | worn to the mounting object. . It is 2nd Embodiment of the sealing device which concerns on this invention, Comprising: It is a schematic longitudinal cross-sectional view which shows an example of the bearing apparatus with which a sealing device is mounted | worn. FIG. 6 is an enlarged view of a portion X in FIG. 5, which is a partially broken vertical cross-sectional view schematically showing a partially enlarged state of being mounted on a mounting target. FIG. 6 is an enlarged view of a Y part in FIG. 5, and is a partially broken longitudinal sectional view schematically showing a partially enlarged state of being attached to a mounting target.

Embodiments of the present invention will be described below with reference to the drawings. In some of the drawings, some of the detailed reference numerals attached to other drawings are omitted.
The sealing device 4 according to the present embodiment seals between the housing 3 and the rotating member 7 inserted through the insertion hole 30 provided in the housing 3. The sealing device 4 is arranged on the atmosphere side with respect to the first lip 80 for sealing the fluid to be sealed such as oil and grease, and suppresses intrusion of foreign matter from the atmosphere side. In addition, an annular second lip 81 extending toward the rotating member 7 is provided. The second lip 81 is formed with a cylindrical portion 81a facing the outer peripheral surface 7a of the rotating member 7 with a predetermined gap H with respect to the outer peripheral surface 7a of the rotating member 7, and the cylindrical portion 81a has an axial direction thereof. The length L is formed to be greater than or equal to the gap H. Details will be described below.

<First Embodiment>
First, a first embodiment of the present invention will be described with reference to FIGS. In the first embodiment, an example in which the sealing device 4A is applied as an oil seal will be described.
FIG. 1 shows a mating portion between an oil pan 1 and a cylinder block 2 in an automobile engine. The oil pan 1 is fastened integrally to the lower end portion of the cylinder block 2 by bolts (not shown), and the oil pan 1 and the cylinder block 2 constitute a mechanical motion mechanism (not shown) and a housing 3 for containing oil. In addition, an insertion hole 30 for leading out the crankshaft 7 is formed at a joint portion between the oil pan 1 and the cylinder block 2.
The insertion hole 30 includes a semicircular hole wall 30a formed on the oil pan 1 side and a semicircular hole wall 30b formed on the cylinder block 2 side. The crankshaft 7 is connected to a piston (both not shown) via a connecting rod and a piston pin, and the vertical reciprocation of the piston is converted into rotation around the axis L1 of the crankshaft 7 (shaft rotation). The mechanism part is configured. The crankshaft 7 is supported by the cylinder block 2 through a bearing (not shown) so as to be rotatable about the shaft, and is led out from the insertion hole 30 as an output shaft.

The sealing device 4 </ b> A of the present embodiment is provided between the mechanical motion mechanism and the housing 3 that stores oil and the crankshaft 7, and suppresses leakage of the oil stored in the housing 3.
The sealing device 4 </ b> A includes a metal core 5 attached to the housing 3 and an annular seal portion 8 fixed to the metal core 5.
The cored bar 5 includes a cylindrical portion 50, a first standing portion 51, an inclined portion 52, and a second standing portion 53. The cylindrical portion 50 is fitted into the hole wall 30a on the oil pan 1 side and the hole wall 30b on the cylinder block 2 side. The first upright portion 51 is formed so as to extend from the one end portion on the sealing target fluid side of the cylindrical portion 50 toward the inner diameter side. The inclined portion 52 is formed so as to extend obliquely from one end portion on the inner diameter side of the first upright portion 51 to the atmosphere side. The second upright portion 53 is formed so as to extend from one end portion on the atmosphere side of the inclined portion 52 to the inner diameter side. Between the cylindrical part 50 and the housing 3, it arrange | positions so that the outer periphery seal | sticker part 83 may interpose. As a result, the outer peripheral seal 83 is interposed between the metal core 5 and the housing 3 in an elastically compressed state, and the metal core 5 is fitted into the housing 3. There is no gap and the sealing is good.

  The seal portion 8 is an annular body made of an elastic body such as rubber, and is integrally molded by being vulcanized and bonded to the core metal 5. The seal portion 8 has a first lip 80 and a second lip 81. The seal portion 8 is arranged mainly on the sealing target fluid side of the cored bar 5. Specifically, an outer peripheral seal portion 83 is disposed on the outer peripheral side of the cylindrical portion 50. And the coating | coated part 84 is distribute | arranged to the sealing object fluid side of the 1st standing part 51 of the metal core 5, and the inclination part 52, and the 1st lip | rip 80 is formed in the internal diameter side. Further, a second lip 81 is formed on the atmosphere side with respect to the first lip 80, and an end portion of the second upright portion 53 is provided with a wrap-around portion 85 arranged to wrap around to the atmosphere side.

  The first lip 80 is a radial lip extending toward the fluid to be sealed while facing the inner diameter side, and has a main function as a lip provided to seal the oil that is the fluid to be sealed. The distal end portion 80 a of the first lip 80 is formed so as to reduce the diameter toward the inside of the housing 3 and suppress oil leakage in the housing 3. The first lip 80 is formed with a thread groove (not shown) on the inner peripheral surface located on the atmosphere side, and the first lip 80 receives oil that goes to the atmosphere side when the crankshaft 7 rotates. It is configured to exhibit a pumping action that pushes back into the housing 3. The innermost diameter side of the distal end portion 80a of the first lip 80 is a sliding portion 80aa that elastically contacts the outer peripheral surface 7a of the crankshaft 7 with an allowance. The first lip 80 is pressed against the crankshaft 7 by a coil spring 82 that is externally provided on the outer peripheral surface of the first lip 80 to seal the oil in the housing 3. Specifically, the coil spring 82 biases the distal end portion 80a of the first lip 80 so as to be tightened in the diameter reducing direction. When the crankshaft 7 is axially rotated by the operation of the mechanical motion mechanism described above, the first lip 80 is in sliding contact with the outer peripheral surface 7a of the crankshaft 7 in an elastically opposed state. Thereby, the leakage to the atmosphere side of the oil accommodated in the housing 3 is suppressed.

FIG. 2 is an enlarged view of the first lip 80 and the second lip 81 of the sealing device 4A shown in FIG.
The second lip 81 is a dust lip that is disposed on the atmosphere side of the first lip 80 and extends toward the crankshaft 7. That is, the second lip 81 extends in the opposite direction to the first lip 80 in the axial direction, and is provided to prevent foreign matters such as dust entering from the atmosphere side from reaching the first lip 80. Yes. The second lip 81 is not slidably contacted with the outer peripheral surface 7a of the crankshaft 7, and is provided in a state where a predetermined gap H is provided as shown in FIG. Thus, since the second lip 81 is arranged with a gap H with respect to the crankshaft 7, even if the first lip 80 exhibits a pumping action, the first lip 80 and the second lip 81 are not affected. There is no negative pressure in the space between. Therefore, the second lip 81 does not stick to the outer peripheral surface 7a of the crankshaft 7, and generation of frictional heat and increase in sliding torque can be suppressed.

The second lip 81 is provided with a cylindrical portion 81a that faces the outer peripheral surface 7a of the crankshaft 7 and is parallel to the axis L1 of the crankshaft 7. The cylindrical portion 81a has an axial length L that is greater than or equal to the gap H. Is formed. The clearance H is the distance from the inner diameter surface 81ab of the cylindrical portion 81a to the outer peripheral surface 7a of the crankshaft 7. The distance between the tip of the first guide projection 81aa and the outer peripheral surface 7a of the crankshaft 7 is smaller than the clearance H. Become. The structure, shape, etc. of the cylindrical portion 81a are not particularly limited, but as will be described later, if the rotation speed of the crankshaft 7 becomes a constant number, the axial length L of the cylindrical portion 81a should be greater than the gap H. Thus, it is known that a Taylor vortex is generated in the gap H. Since a Taylor vortex is formed between the inner diameter surface 81ab of the cylindrical portion 81a and the outer peripheral surface 7a of the crankshaft 7, the Taylor vortex serves as a barrier, and foreign matter can be prevented from entering the gap H. Therefore, the amount of foreign matter that passes through the gap H of the second lip 81 from the atmosphere side and reaches the first lip 80 on the sealing target fluid side can be suppressed. If the amount of foreign matter reaching the first lip 80 can be suppressed in this way, the foreign matter can be prevented from being bitten by the sliding portion of the first lip 80 and worn, so that the sealing performance can be extended. it can.
The length L in the axial direction of the cylindrical portion 81a of the second lip 81 varies depending on the shape of the second lip 81. In the present embodiment, the cylindrical portion 81a is most sealed with the first guide protrusion 81aa provided on the most atmospheric side. The axial distance from the first guide protrusion 81aa provided on the target fluid side is defined as the axial length L of the cylindrical portion 81a of the second lip 81.

  Here, the Taylor vortex is a periodic vortex train generated so as to wrap around the crankshaft 7 in the circumferential direction. For example, when the shaft diameter of the crankshaft 7 is 80 mm and the gap H is 1.3 mm, Taylor vortices are generated when the rotation speed of the crankshaft 7 reaches 1000 to 1300 r / m. Then, when the rotation speed of the crankshaft 7 reaches 1300 to 1500 r / m, the vortex flow of the generated Taylor vortex becomes stable. In FIG. 2 etc., the arrow described between 1st guide protrusion 81aa and 81aa has shown the Taylor vortex.

If the gap H and the axial length L of the cylindrical portion 81a are defined as described above, a Taylor vortex can be generated, but the first guide protrusion 81aa formed on the inner diameter surface 81ab of the cylindrical portion 81a. By adjusting the number and interval of formation, it is possible to intentionally generate a Taylor vortex having a regular and stable vortex flow.
As shown here, the cylindrical portion 81a of the second lip 81 has a plurality of first guide protrusions 81aa, a second guide protrusion 81b, and a tip corner 81c. The plurality of first guide protrusions 81aa protrude toward the outer peripheral surface 7a of the crankshaft 7. The plurality of first guide protrusions 81aa are each formed in the same shape. In the example shown in FIG. 2, the number of the first guide protrusions 81aa is three, and the gap H and the distance D have a relationship of H≈D. Further, the distance D between the adjacent first guide protrusions 81aa is equal in all the places. FIG. 2 shows the second lip 81 when the distance L between the first guide protrusion 81aa closest to the atmosphere side and the first guide protrusion 81aa closest to the fluid to be sealed is an even multiple of the gap H. Such stable vortex Taylor vortices T2 and T3 can be generated.

  Since the first guide protrusion 81aa provided as described above guides the vortex flow of the Taylor vortices T2 and T3 in a predetermined direction, the Taylor vortices T2 and T3 are stabilized. The second guide protrusion 81b is provided between the second lip 81 and the first lip 80, and is formed so as not to protrude toward the crankshaft 7 from the cylindrical portion 81a. Specifically, the second guide protrusion 81 b is provided on the inner peripheral surface of the base end side of the second lip 81. The second guide protrusion 81b is farther than the gap H from the first guide protrusion 81aa closest to the fluid to be sealed. According to the second guide protrusion 81b, Taylor vortices T4 and T5 (see FIG. 2) pass along the path where foreign matter passes between the second lip 81 and the outer peripheral surface 70a of the crankshaft 7 and faces the fluid to be sealed. ) Can be generated stably.

  The tip end corner portion 81c on the atmosphere side of the second lip 81 is a curved inclined surface 81ca whose diameter increases toward the atmosphere side. If the tip corner 81c is formed to be the inclined surface 81ca as described above, a Taylor vortex T1 is generated between the tip corner 81c on the atmosphere side of the second lip 81 and the outer peripheral surface 7a of the crankshaft 7. Can be made. The Taylor vortex T1 becomes an air flow that suppresses the entry of foreign matter before the foreign matter enters the gap H between the cylindrical portion 81a of the second lip 81 and the outer peripheral surface 7a of the crankshaft 7.

  According to the above configuration, when the crankshaft 7 reaches a certain number of revolutions, the Taylor vortices T2 and T3 in the direction of the arrow are generated between the first guide protrusions 81aa and 81aa, and the Taylor vortex T2 is adjacent thereto. Taylor vortex T1 is also generated on the atmosphere side. The Taylor vortex T1 becomes a vortex in the direction in which foreign matter is guided to the atmosphere side (see the direction of the arrow T1 in FIG. 2), so that the foreign matter can be effectively prevented from entering at the gap portion of the tip corner portion 81c serving as the foreign matter entry port. be able to. Further, a Taylor vortex T4 is also generated on the fluid to be sealed adjacent to the Taylor vortex T3. The second guide protrusion 81b generates a Taylor vortex T5 having a vortex direction different from that of the Taylor vortex T4 between the second lip 81 and the first lip 80. Thereby, even if the foreign matter passes between the cylindrical portion 81a of the second lip 81 and the outer peripheral surface 70a of the crankshaft 7, Taylor vortices T4 and T5 are generated in the path to the first lip 80. Therefore, the Taylor vortex T <b> 5 acts to return the foreign matter to the atmosphere, and the foreign matter can be prevented from reaching the sliding portion 80 aa of the first lip 80.

  The configuration of the first guide protrusion 81aa is not limited to the illustrated example, and may be a curved shape with a gentle cross section as shown in FIG. 2 or a substantially triangular mountain shape. In addition, it is desirable that the first guide protrusion 81aa be provided in an annular shape continuously along the circumferential direction from the viewpoint of stably and regularly generating Taylor vortices, but the first guide protrusion 81aa provided intermittently. The portion 81aa is not excluded. Hereinafter, still another example of the first guide protrusion 81aa will be described.

3A and 3B show a modification in which the number of first guide protrusions 81aa formed is different from the example of FIG. Portions common to those in FIG. 2 are denoted by common reference numerals, and description of the common portions is omitted.
The number of first guide protrusions 81aa formed is not particularly limited. As shown in FIG. 3A, the number of first guide protrusions 81aa is an odd number of 3 or more, and the most air guide side first guide protrusion 81aa is the most. The interval L with the first guide protrusion 81aa on the sealing target fluid side may be an even multiple of the gap H. As shown here, 2n + 1 first guide protrusions 81aa may be provided, and a gap D equivalent to the gap H may be provided. In this case, in FIG. 3A, the gap H and the length L have a relationship of L≈2nH.
According to the above configuration, by providing the plurality of first guide protrusions 81aa at desired positions corresponding to the size and shape of the second lip 81, it is possible to stabilize the position and number of occurrence of Taylor vortices. it can.
Note that FIG. 3A shows an example in which the second guide protrusion 81b is not provided. If the configuration is such that a large number of Taylor vortices are generated as shown in FIG. 3A, the number of barriers will increase, so the second guide protrusion 81b may be omitted.

  FIG. 3B shows an example in which the first guide protrusion 81aa is not provided. As shown in FIG. 3B, the first guide protrusion 81aa may be omitted if the axial length L of the cylindrical portion 81a is greater than or equal to the gap H. In this case, it is preferable to form the cylindrical portion 81a so that the length L in the axial direction has a relationship of L≈2nH. Even if the first guide protrusion 81aa does not exist, if the crankshaft 7 reaches a predetermined rotational speed, a Taylor vortex is generated between the cylindrical portion 81a and the crankshaft 7 so that entry of foreign matter is suppressed. become.

FIGS. 4A and 4B show an example in which guide recesses 7b and 60a for generating Taylor vortices are also formed on the rotating member side. Portions common to those in FIG. 2 are denoted by common reference numerals, and description of the common portions is omitted.
In FIG. 4A, a plurality of guide recesses 7 b are formed on the outer peripheral surface 7 a of the crankshaft 7. The formation position of the guide recess 7b is formed to face the space between the adjacent first guide protrusions 81aa and 81aa. Further, Taylor vortices can be stably generated in the space formed by the space between the adjacent first guide protrusions 81aa and 81aa and the guide recess 7b. Also in this example, the formation position and the number of formations of the first guide protrusion 81aa and the like are not limited, and the guide recess 7b is formed corresponding to the formation position of the first guide protrusion 81aa.

FIG. 4B is an example in which the metal ring 6 is fitted to the outer peripheral surface 7 a of the crankshaft 7, and the guide recess 60 a is formed in the fitting portion 60 of the metal ring 6. The metal ring 6 is provided in order to suppress entry of foreign matter from the atmosphere side, and has a substantially L-shaped cross section. The metal ring 6 includes a fitting portion 60 that is fitted to the outer peripheral surface 7 a of the crankshaft 7, and a flange portion 61 that is bent in a substantially vertical direction from one end portion on the atmosphere side of the fitting portion 60. . In the example shown in FIG. 4B as well, the guide recess 60a is formed to face the space between the adjacent first guide protrusions 81aa and 81aa, and the space between the adjacent first guide protrusions 81aa and 81aa. A Taylor vortex is stably generated in the space formed by the guide recess 7b.
According to the above, since the metal ring 6 suppresses the entry of foreign matter and the tailor vortex is generated in the gap H, the entry of foreign matter can be further effectively suppressed, and the sealing device 4A is sealed. The performance can be extended.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, an example in which the sealing devices 4B and 4C are applied as a bearing unit sealing device will be described. Portions that are common to the first embodiment are given the same reference numerals as much as possible, and descriptions of the configuration, operation, and effects are omitted.

FIG. 5 shows a bearing unit 10 that supports a wheel (not shown) of an automobile so as to be axially rotatable. The bearing unit 10 is generally formed between an outer ring 11, a hub ring 70, an inner ring member 71 fitted and integrated on the vehicle body side of the hub ring 70, and the outer ring 11, the hub ring 70, and the inner ring member 71. And two rows of rolling elements (balls) 14. In this example, the outer ring 11 is fixed to a vehicle body (not shown) of the automobile and constitutes the housing 3. The hub wheel 70 and the inner ring member 71 constitute an inner ring 7 as an inner member, which is a rotating member and is inserted through an insertion hole 30 provided in the outer ring 11. The hub wheel 70 is coaxially spline-fitted with the drive shaft 16, and the drive shaft 16 is connected to a drive source (drive transmission unit) (not shown) via the constant velocity joint 15. The drive shaft 16 is integrated with the hub wheel 70 by a nut 16a, and the hub wheel 70 is prevented from being detached from the drive shaft 16. The inner ring 7 (hub wheel 70 and inner ring member 71) is a rotating member that can rotate around the axis L2 with respect to the outer ring 11, and the outer ring 11 and the inner ring 7 constitute two members that rotate relatively. An annular bearing space S is formed between the two members. In the bearing space S, two rows of rolling elements 14 are held by the retainer 14a so that the race ring 11a of the outer ring 11, the hub ring 70, and the race rings 70e and 71b of the inner ring member 71 can roll. It is intervened. The hub wheel 70 has a cylindrical hub wheel main body 70b and a hub flange 70d formed so as to extend radially outward from the hub wheel main body 70b via a rising base 70c. The wheels are attached and fixed by nuts (not shown). In the following, the side facing the wheel along the axis L2 direction (left side in FIG. 5) is referred to as the wheel side, and the side facing the vehicle body (right side in FIG. 5) is referred to as the vehicle body side.
In the first embodiment, the reference numeral “7” is attached to the crankshaft as the rotating member, and therefore, the inner ring that is the rotating member in the second embodiment is assigned the reference numeral “7”.

Sealing devices 4B and 4C are mounted between the outer ring 11 and the inner ring member 71 and between the outer ring 11 and the hub ring 70 at both ends along the axis L2 direction of the bearing space S. Both end portions along the L2 direction are sealed. By these sealing devices 4B and 4C, intrusion of muddy water or the like into the bearing space S and leakage of a lubricant (grease or the like) that is a fluid to be sealed filled in the bearing space S to the outside are prevented.
Of the sealing devices 4B and 4C, an example in which the present invention is applied to the sealing device 4B on the vehicle body side will be described first with reference to FIG.

The sealing device 4B will be described with reference to FIG. FIG. 6 is an enlarged view of a portion X in FIG. The sealing device 4 </ b> B includes a cored bar 20 having a cylindrical part 200 fitted to the outer ring 11, a seal part 21 fixed to the cored bar 20, and a slinger 90 fitted to the inner ring member 71. .
The metal core 20 includes a cylindrical portion 200 that is fitted in the vehicle body side inner diameter surface 11b of the outer ring 11, and an inward flange portion 201 that extends from the end portion 200a on the bearing space S side of the cylindrical portion 200 toward the inner diameter side. . The slinger 90 includes a slinger cylindrical portion 900 that is fitted on the outer peripheral surface 71a of the inner ring member 71, and an outward flange portion 901 that extends from the end portion 900a opposite to the bearing space S of the slinger cylindrical portion 900 to the outer diameter side. Have. The core metal 20 and the slinger 90 are formed into a substantially L-shaped cross section by pressing a steel plate, and constitute a so-called pack seal by combining them facing each other.

  The seal portion 21 is made of an elastic body such as rubber, and is integrally molded by vulcanizing and bonding to the cored bar 20. The seal portion 21 includes a seal lip base 210, a lip portion 211 that extends from the seal lip base 210 and that is provided closest to the atmosphere side, and a second portion that is provided closer to the inner diameter side than the lip portion 211 and extends toward the atmosphere side. It has a lip 81 and a first lip 80 extending toward the fluid to be sealed. The number and shape of the lip portion 211, the first lip 80, and the second lip 81 are not limited to the illustrated example. The inner surface 81ab of the cylindrical portion 81a is formed with a predetermined gap H with respect to the slinger cylindrical portion 900 of the slinger 90. The cylindrical portion 81a has an axial length L that is greater than or equal to the gap H. Moreover, the point which has the some 1st guide protrusion 81aa, the 2nd guide protrusion 81b, and the front-end | tip corner | angular part 81c in the cylindrical part 81a is the same as that of 1st Embodiment. The example of FIG. 6 is also provided with three first guide protrusions 81aa and the same distance D as the gap H as in the example of FIG. 2 of the first embodiment. Therefore, in this case, the gap H and the interval D have a relationship of H≈D. Further, if the second lip 81 is designed so that the distance L between the first guide protrusion 81aa on the most atmospheric side and the first guide protrusion 81aa on the most fluid to be sealed side is approximately twice the gap H, the second lip 81 is stable. A vortex Taylor vortex can be generated.

The structure that easily generates the Taylor vortex described in the first embodiment can also be applied to such a pack seal type sealing device 4B. According to this, the second lip 81 does not stick to the slinger cylindrical portion 900, and generation of frictional heat and increase in sliding torque can be suppressed. Further, intrusion of foreign matter from the atmosphere side can be suppressed, and foreign matter can be prevented from being bitten by the sliding portion 80aa of the first lip portion 80 and worn, so that the life of the sealing performance can be extended.
Although not shown, also in this sealing device 4B, the cylindrical portion 81a can be configured as shown in FIGS. 3A and 3B, and the rotating member side as shown in FIG. 4B. A guide recess 60a may be formed in the slinger cylindrical portion 900.

Next, the sealing device 4C will be described with reference to FIG. FIG. 7 is an enlarged view of a Y portion in FIG. The sealing device 4C is a wheel-side sealing device 4C.
The sealing device 4 </ b> C includes a cored bar 40 fitted into the inner diameter surface 11 c on the wheel side of the outer ring 11, and a seal portion 41 fixed to the cored bar 40.
The core metal 40 is formed by pressing a steel plate. The cored bar 40 includes a cylindrical portion 400 that is fitted into the inner diameter surface 11 c of the outer ring 11, and an inward flange portion 401 that extends from the wheel-side end portion 400 a of the cylindrical portion 400 toward the inner diameter side. The seal part 41 is made of an elastic body such as rubber and is integrally fixed to the cored bar 40 by vulcanization molding. The seal portion 41 includes an outer peripheral seal portion 410 disposed on the outer peripheral side of the cylindrical portion 400, a lip portion 411 provided closest to the atmosphere side, and a first lip portion 411 provided on the inner diameter side and extending toward the atmosphere side. Two lips 81 and a first lip 80 extending toward the fluid to be sealed.

  The numbers and shapes of the lip portion 411, the second lip 81, and the first lip 80 are not limited to the illustrated examples. The second lip 81 is formed with a cylindrical portion 81a in a state where a predetermined gap H is left with respect to the hub wheel main body 70b which is a rotating member. The cylindrical portion 81a has an axial length L that is greater than or equal to the gap H. Moreover, the point which has the some 1st guide protrusion 81aa, the 2nd guide protrusion 81b, and the front-end | tip corner | angular part 81c in the cylindrical part 81a is the same as that of 1st Embodiment. The example of FIG. 7 is also provided with three first guide protrusions 81aa and a gap D substantially equal to the gap H as in the example of FIG. 2 of the first embodiment. Therefore, in this case, the gap H and the interval D have a relationship of H≈D. Further, if the second lip 81 is designed so that the distance L between the first guide protrusion 81aa on the most atmospheric side and the first guide protrusion 81aa on the most fluid to be sealed side is approximately twice the gap H, the second lip 81 is stable. A vortex Taylor vortex can be generated.

Also in such a sealing device 4C, the structure that easily generates the Taylor vortex described in the first embodiment can be applied, the second lip 81 does not stick to the peripheral surface 70ba of the hub wheel main body 70b, and frictional heat is generated. And increase in sliding torque can be suppressed. In addition, since the entry of foreign matter from the atmosphere side can be suppressed, it is possible to prevent the foreign matter from being bitten by the sliding portion of the first lip portion 80 and being worn away, so that the life of the sealing performance can be extended.
Although not shown, also in this sealing device 4C, the cylindrical portion 81a can be configured as shown in FIGS. 3 (a) and 3 (b), and the rotating member side as shown in FIG. 4 (a). A guide recess may be formed in the hub wheel main body 70b and the rising base 70c. Further, in the case of a hub seal provided with a deflector made of a metal material or the like, a guide recess as shown in FIG. 4B may be formed on the deflector side.

  In the above embodiment, the sealing device 4 according to the present invention has been described as an example applied as the sealing device 4B, 4C assembled to the oil seal 4A or the bearing unit for the vehicle in the automobile engine. The housing 3 and the rotating member 7 inserted through the insertion hole 30 provided in the housing 3 can be applied. Therefore, for example, the housing 3 of the first embodiment may be a housing such as a geared motor or a pump used in a ship or an agricultural machine. In this case, the movable shaft is the output shaft, and the mechanical motion mechanism unit is configured by the gear mechanism and the output shaft configured by meshing a plurality of gears. Further, the shapes and configurations of the core bars 5, 20, 40, the seal portions 8, 21, 41, the slinger 90, the metal ring 6 and the like are not limited to those shown in the figure, and the first lip 80, the second lip 81, etc. The shape and number of the lip portions are not limited to those shown in the drawings, and other modes can be adopted. Therefore, for example, in the first embodiment, if the first lip 80 has a configuration capable of exhibiting a pumping action, a mode in which no thread groove is formed on the first lip 80 can be employed. The cylindrical portion 81a of the second lip 81 is not limited to the illustrated example as long as the axial length L satisfies the relationship that the gap H is greater than or equal to the gap H, and other modes can be adopted. . In the first embodiment, the curved end surface 81ca of the second lip 81 is formed with a curved inclined surface 81ca. However, the present invention is not limited to this, and a linear inclined surface 81ca may be formed. . Furthermore, it goes without saying that an encoder for detecting rotation may be fixed to the slinger 90.

4 (4A, 4B, 4C) Sealing device 3 (1, 2, 11) Housing (oil pan, cylinder block, outer ring)
30 Insertion hole 7 (7, 71, 70b, 70c) Rotating member (crankshaft, inner ring member, hub ring body, upright base)
7a, 71a, 70ba (outer) peripheral surface 5, 20, 40 cored bar 8, 21, 41 seal portion 80 first lip 81 second lip 81a cylindrical portion H gap L length of cylindrical portion in the axial direction 81aa first guide Projection D First guide projection spacing 81b Second guide projection 81c Tip corner

Claims (7)

In a sealing device for sealing between a housing and a rotating member inserted through an insertion hole provided in the housing,
A metal core fitted to the housing, and a seal portion fixed to the metal core,
The seal portion includes an annular first lip for sealing a fluid to be sealed;
An annular second lip that is disposed on the atmosphere side with respect to the first lip to suppress entry of foreign matter from the atmosphere side and extends toward the rotating member;
The second lip is formed with a cylindrical portion facing the peripheral surface of the rotating member with a predetermined gap with respect to the peripheral surface of the rotating member,
The cylindrical portion is formed with a length in the axial direction that is greater than or equal to the gap. The sealing device according to claim 1,
The sealing device according to claim 1, wherein the cylindrical portion is provided with a plurality of first guide protrusions protruding toward the peripheral surface of the rotating member. The sealing device according to claim 2.
The sealing device according to claim 1, wherein the plurality of first guide protrusions are arranged with an interval equivalent to the gap. The sealing device according to claim 2 or claim 3,
The first guide protrusion is an odd number of 3 or more,
The sealing device characterized in that the distance between the first guide projection on the most atmospheric side and the first guide projection on the most fluid to be sealed is an even multiple of the gap. In the sealing device according to any one of claims 1 to 4,
A sealing device characterized in that a second guide protrusion is provided between the second lip and the first lip so as not to protrude from the cylindrical portion toward the rotating member. In the sealing device according to any one of claims 1 to 5,
The sealing device according to claim 1, wherein a tip end corner portion on the atmosphere side of the second lip is an inclined surface having a diameter increasing toward the atmosphere side. In the sealing device according to any one of claims 1 to 6,
The first lip is configured to exhibit a pumping action of pushing back the oil as the medium to be sealed going to the atmosphere side into the housing when the rotating member rotates. .

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