JP2008240993A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device capable of suitably maintaining sealing action even when a main lip is worn, and capable of preventing change of rotation torque of a bearing device. <P>SOLUTION: The sealing device is mounted in an annular space formed between an inner member 20 and an outer member 21 relatively rotating with each other. The sealing device is provided with a slinger 2 having a cylindrical part 2a pressed in one member 20 of the inner member 20 and the outer member 21 and an annular plate part 2b, and a seal body 3 pressed in the other member 21 of the inner member 20 and the outer member 21 and having a main lip 7 slidably and closely contacting with the cylindrical part 2a. At least one of a spare lip 10 is provided on an outer side B of the main lip 7, which is not brought into contact with the cylindrical part 2a ordinarily, and is brought into contact with the cylindrical part 2a by abrasion of the main lip 7 by rotation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sealing device for sealing an annular space between an inner member and an outer member that rotate relative to each other.

  Conventionally, as a sealing device used for a wheel rolling bearing device (hub unit), for example, there is one which is mounted in an annular space formed between an inner member and an outer member that rotate relative to each other. The sealing device includes a slinger that is press-fitted into the inner member, and a seal main body that is press-fitted into the outer member. The seal main body is fixed to the mandrel that is press-fitted into the outer member, The seal member includes a main lip, an auxiliary lip, and a side lip that are slidably in close contact with the slinger (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 4-50724 (FIG. 2)

In the above-described sealing device, in particular, the main lip is in contact with the slinger with a large interference compared to other auxiliary lips and side lips. For this reason, the main lip is likely to wear due to contact with the slinger, and as this wear progresses, the contact surface pressure against the slinger changes, and a proper sealing action cannot be obtained, or the rotational torque of the bearing device changes. There was concern about doing it.
The present invention has been made in view of such circumstances, and provides a sealing device that can properly maintain a sealing action even when a main lip is worn and that can prevent a change in rotational torque of a bearing device. With the goal.

  A sealing device according to the present invention is a sealing device mounted in an annular space formed between an inner member and an outer member that rotate relative to each other, and is press-fitted into one of the inner member and the outer member. A slinger having a cylindrical portion and an annular plate portion extending radially from the cylindrical portion, and a main lip that is press-fitted into the other member of the inner member and the outer member and slidably contacts the cylindrical portion One or more preliminary lips on the outer side of the main lip, which are normally not in contact with the cylindrical portion and are in contact with the cylindrical portion when the main lip is worn by the rotation. It is characterized by being provided.

According to the sealing device of the present invention, a spare lip is provided on the outer side of the main lip, and the contact surface pressure between the main lip and the slinger is abruptly brought into contact with the slinger as the wear of the main lip advances. It can be prevented from changing. Thereby, further promotion of wear in the main lip is prevented, and the sealing action can be properly maintained.
In addition, since the spare lip contacts the slinger instead of the main lip, a sudden change in the contact area between the main lip and the slinger accompanying the progress of wear is suppressed, thereby preventing a change in the rotational torque of the bearing device. be able to.

In the sealing device, a plurality of the preliminary lips are provided, and the plurality of preliminary lips are preferably formed so that the lip inner diameter increases from the bearing inner side toward the outer side and the lip width decreases. .
In this case, since the plurality of spare lips are formed so that the inner diameter of the lip increases from the bearing inner side toward the outer side, they contact the slinger sequentially from the bearing inner side. Here, since the force with which the auxiliary lip pushes the slinger decreases toward the outside, the surface pressure when each auxiliary lip comes into contact with the slinger is reduced by gradually reducing the lip width toward the outside. It can be kept constant.

  According to the sealing device of the present invention, since one or more auxiliary lips are provided on the outer side of the main lip, the sealing action can be properly maintained even when the main lip is worn, and the rotational torque of the bearing device is changed. Can be prevented.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a cross-sectional explanatory view showing a sealing device according to one embodiment of the present invention. The sealing device 1 is used, for example, in a rolling bearing device (hub unit) to which a vehicle wheel is attached, and is disposed between an inner member 20 and an outer member 21 that are concentrically and relatively rotatable. Mounted in the annular space, the lubricant inside the bearing A is prevented from leaking to the outer side B, and foreign matter such as muddy water is prevented from entering the bearing inside A from the outer side B. In addition, the sealing device 1 shown in FIG. 1 has shown the free state before a deformation | transformation before it is mounted | worn between the inner member 20 and the outer member 21. FIG.

The sealing device 1 includes a slinger 2 that is press-fitted into the inner member 20 and a seal body 3 that is press-fitted into the outer member 21.
The slinger 2 is a substantially L-shaped annular member having a cylindrical portion 2a that is press-fitted into the inner member 20, and an annular plate portion 2b that is bent radially outward from the outer side B end portion of the cylindrical portion 2a. is there.
The seal body 3 includes an annular cored bar 4 having a substantially L-shaped cross section, and a seal member 5 fixed to the cored bar 4.

The core metal 4 is an annular member made of metal (for example, SPCC), and is bent inward in the radial direction from the cylindrical portion 4a press-fitted into the outer member 21 and the end portion on the bearing inner side A of the cylindrical portion 4a. It is comprised with the cyclic | annular board part 4b.
The seal member 5 is made of an elastic member such as synthetic rubber (for example, acrylonitrile-butadiene rubber (NBR), acrylic rubber (ACM)), and is fixed to the core metal 4 by adhesion or baking by vulcanization. The seal member 5 includes a main body portion 6, a main lip 7, an auxiliary lip 8, a side lip 9, and a spare lip 10.

  The main body 6 is composed of an outer covering portion 6a that covers a region on the outer side B of the cored bar 4 and an inner peripheral portion 6b that covers a region on the inner peripheral side of the annular plate portion 4b. The main lip 7 extends from the inner peripheral part 6b of the main body 6 to the inner member 20 side and to the outer side B, and the auxiliary lip 8 extends from the inner peripheral part 6b of the main body part 6 to the inner member 20 side and to the bearing. The side lip 9 extends to the inside A side, and extends in a skirt shape from the inner peripheral side of the outer side covering portion 6a of the main body portion 6 to the outer side B in a radially outward direction.

  The spare lip 10 is provided on the outer side B of the main lip 7 and does not normally contact the cylindrical portion 2a of the slinger 2 but contacts the cylindrical portion 2a as the main lip 7 is worn by the rotation of the inner member 20. It is. One or more spare lips 10 can be provided. Here, three lips of the first spare lip 10a, the second spare lip 10b, and the third spare lip 10c from the bearing inner side A toward the outer side B are provided. Is formed.

When the main lip 7, the auxiliary lip 8, the side lip 9, and the spare lip 10 are assembled to the slinger 2, the tip of the main lip 7 faces the outer side B, and the tip of the auxiliary lip 8 faces the bearing inner A side. Each is in sliding contact with the surface of the cylindrical portion 2a of the slinger 2, thereby preventing the lubricant inside the bearing A from leaking to the outside B.
The tip of the side lip 9 faces the outer peripheral side and is in sliding contact with the surface of the annular plate portion 2b of the slinger 2. This prevents foreign matter such as muddy water from entering the bearing inside A from the outside side B. ing. The tip of the preliminary lip 10 does not contact the cylindrical portion 2a of the slinger 2 at this stage as described above.

FIG. 2 is an enlarged cross-sectional explanatory view of the main lip 7 and the spare lip 10.
The main lip 7 has a substantially V-shaped cross-sectional shape that becomes narrower inward in the radial direction (the axial width dimension becomes smaller). If the minimum diameter (top) is the lip tip 7a, The lip inner diameter of the lip 7 (the inner diameter of the lip tip 7a) can be expressed as D0. Also, on the inner peripheral surface of the main lip 7, the surface on the outer side B from the lip tip 7a is the first inclined surface 7b, and the surface on the bearing inner side A from the lip tip 7a is the second inclined surface 7c. The lip width can be represented by an angle θ0 formed by the first inclined surface 7b and the second inclined surface 7c.

Similarly to the main lip 7, the preliminary lip 10 has a substantially V-shaped cross section, and the lip inner diameters of the first preliminary lip 10a, the second preliminary lip 10b, and the third preliminary lip 10c are D1, D2, D3, respectively. The lip widths are represented as θ1, θ2, and θ3, respectively. Then, since the lip inner diameter of the auxiliary lip 10 increases from the bearing inner side A toward the outer side B, the relationship between the inner diameters of the auxiliary lips 10 is D1 <D2 <D3. Since it is not in contact with the slinger 2, the magnitude relationship of the lip inner diameters of the main lip 7 and the spare lip 10 is D0 <D1 <D2 <D3.
Further, since the lip width of the auxiliary lip 10 is smaller than that of the main lip 7 and becomes smaller from the bearing inner side A toward the outer side B, the magnitude relationship between the lip widths of the main lip 7 and the auxiliary lip 10 is θ0. >Θ1>θ2> θ3.

The main lip 7 is in contact with the cylindrical surface 2a of the slinger 2 with an appropriate pressure. When the main lip 7 is worn, a spare lip 10 provided on the outer side B of the main lip 7 From the A side toward the outer side B, the first preliminary lip 10a, the second preliminary lip 10b, and the third preliminary lip 10c come into contact with the cylindrical surface 2a of the slinger 2 in this order (see the arrow in FIG. 2).
More specifically, when the main lip 7 is worn, the contact surface with the slinger 2 becomes flat, and the first preliminary lip 10a having an inner diameter smaller than that of the main lip 7 (D0 <D1) is gradually formed on the cylindrical surface 2a of the slinger 2. Proximity.

  When the main lip 7 further wears, the first preliminary lip 10a comes into contact with the cylindrical surface 2a of the slinger 2 and sealing is performed by the first preliminary lip 10a. Thus, as the wear of the main lip 7 progresses, the contact pressure between the main lip 7 and the cylindrical surface 2a of the slinger 2 increases as the first preliminary lip 10a contacts the cylindrical surface 2a of the slinger 2. Can be prevented. Thereby, further promotion of wear in the main lip 7 is prevented.

  Next, when the first preliminary lip 10a is worn, the second preliminary lip 10b having an inner diameter larger than the first preliminary lip 10a (D1 <D2) comes into contact with the cylindrical surface 2a of the slinger 2, and the second preliminary lip 10b is worn. Then, the third preliminary lip 10c whose inner diameter is larger than the second preliminary lip 10b (D2 <D3) contacts the cylindrical surface 2a of the slinger 2. When the main lip 7 is worn out to a certain extent, a gap is formed between the slinger 2 and the cylindrical surface 2a, and the spare lip 10 is in contact with the lip of the front stage (bearing inside A side) of the slinger 2 It does not contact the cylindrical surface 2a.

Therefore, if only the main lip 7 is used, the contact area increases with wear and the rotational torque increases. However, if the spare lip 10 is provided on the outer side B of the main lip 7, the wear of the main lip 7 proceeds to some extent. Since the preliminary lip 10 contacts the cylindrical surface 2a of the slinger 2 in order from the bearing inner side A, an increase in the contact area of the main lip 7 can be suppressed, and a change or increase in the rotational torque of the bearing device can be prevented. .
Furthermore, since the force with which the preliminary lip 10 pushes the cylindrical surface 2a of the slinger 2 decreases toward the outer side B, by gradually decreasing the lip width toward the outer side B (θ1>θ2> θ3), The contact surface pressure between each preliminary lip 10a, 10b, 10c and the cylindrical surface 2a of the slinger 2 can be kept substantially constant.

In the sealing device 1 configured as described above, the auxiliary lip 10 is provided on the outer side B of the main lip 7, and the auxiliary lip 10 comes into contact with the slinger 2 as the main lip 7 wears. A change in contact surface pressure between the lip 7 and the slinger 2 can be prevented, whereby further wear of the main lip 7 is prevented from being promoted, and the sealing action can be maintained.
Further, as the wear progresses, the spare lip 10 comes into contact with the slinger 2 instead of the main lip 7, thereby suppressing a rapid change in the contact area between the main lip 7 and the slinger 2, thereby reducing the rotational torque of the bearing device. Changes can also be suppressed.

In addition, this invention is not limited to the said embodiment.
For example, in the above embodiment, the number of spare lips 10 is 3, but the number is not limited to this, and any number of spare lips 10 may be provided as long as it is 1 or more. It can be appropriately changed in consideration of the material of the seal member 5, the size and shape of the main lip 7, the size of the space for forming the auxiliary lip 10, and the like.

In the above embodiment, the case where the slinger 2 is press-fitted into the inner member 20 and the seal body 3 is press-fitted into the outer member 21, but conversely, the seal body 3 is inserted into the inner member 20 and the slinger 2 is inserted. It is also possible to carry out by press-fitting each into the outer member 21.
Further, a spring ring (garter spring) may be attached to the outer peripheral surface of the main lip 7.

It is a section explanatory view showing the sealing device concerning one embodiment of the present invention. FIG. 2 is an enlarged cross-sectional explanatory view of a main lip and a preliminary lip in FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sealing device 2 Slinger 3 Seal main body 4 Core metal 5 Seal member 6 Main body part 7 Main lip 10 Spare lip 20 Inner member 21 Outer member A Bearing inside B External side

Claims (2)

A sealing device mounted in an annular space configured between an inner member and an outer member that rotate relative to each other,
A slinger having a cylindrical portion press-fitted into one of the inner member and the outer member, and an annular plate portion extending in a radial direction from the cylindrical portion;
A seal body having a main lip that is press-fitted into the other member of the inner member and the outer member and is slidably in close contact with the cylindrical portion;
One or more preliminary lips that are not in contact with the cylindrical portion at all times and are in contact with the cylindrical portion when the main lip is worn by the rotation are provided on the outer side of the main lip. Sealing device.   2. The sealing device according to claim 1, wherein a plurality of the preliminary lips are provided, and the plurality of preliminary lips are formed so that a lip inner diameter increases and a lip width decreases from the bearing inner side toward the outer side. .

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