JP3358879B2 - Bearing sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device for preventing lubricant from leaking from the inside of a bearing and entry of foreign matter from the outside, and more particularly to a contact-type sealing device.

[0002]

2. Description of the Related Art As one of sealing devices for bearings, there is a so-called contact type in which a lip is brought into contact with a seal groove provided in a rotating raceway to seal between the lip and the raceway.

A sealing device of this type is, for example, shown in FIG.
As shown in (a), a substantially annular seal body (22) is attached to an attachment groove (21) provided on the inner peripheral surface of the outer ring (20), and a lip (23) of the seal body (22) is attached to the inner ring ( It is configured by slidingly contacting a seal groove (25) formed on the outer peripheral surface of (24).

[0004]

In the contact-type sealing device, slippage occurs between the lip (23) and the seal groove (25). Therefore, depending on the use conditions of the bearing, a so-called stick-slip may occur at the sliding contact portion between the two, and the lip (23) may vibrate self-excitingly to generate an unpleasant squeal.

Accordingly, an object of the present invention is to provide a bearing sealing device capable of preventing the generation of such a seal squeal.

[0006]

In order to achieve the above object,
According to the present invention, in a sealing device for a bearing including a lip that is in sliding contact with a seal groove provided in one of the races, the lip is brought into contact with the seal groove from a radial direction, and a part of the lip and the raceway are formed. A vertical portion extending in the radial direction was provided on the other side of the raceway than the sliding contact portion, and the surface roughness of the seal groove was set to 1S to 6S.

[0007]

[0008]

[0009]

The following three factors have been clarified as the causes of the generation of the squealing sound by the research of the present applicant.

[0010] When the sealing device is an axial contact type, a squeal is likely to occur. Here, the axial contact type refers to one in which the lip (23) is brought into contact with the seal groove (25) from the axial direction as shown in FIG.
On the other hand, as shown in FIG.
In the radial contact type sealing device in which the contact is made in the radial direction with the seal groove (25 '), stick-slip hardly occurs and the effect of suppressing generation of squealing noise is large. As shown in FIG. 1, the sealing device of the present invention is of a radial contact type in which the lip (12) is brought into contact with the sealing surface (15) from the radial direction.

If the rigidity of the lip is insufficient, a squealing sound is likely to be generated. If the rigidity of the lip is insufficient, the lip rotating along with the inner ring is greatly deformed under the influence of the centrifugal force. . In order to increase the rigidity of the lip, it is easy to increase or decrease the thickness of the lip. However, in this case, the elasticity of the lip is reduced, which may cause adverse effects such as a decrease in sealing function and an increase in shaft torque. In the present invention, a vertical portion extending in the radial direction is provided on a part of the lip and on the other side of the raceway than the sliding contact portion with the raceway to increase the volume of the lip. The rigidity can be increased in the radial direction without lowering the rigidity.

If the surface roughness of the seal groove is too small, a squeal sound is likely to be generated. That is, in order to prevent generation of squealing noise, the seal groove needs to have an appropriate surface roughness. Conventionally, the seal groove is mirror-finished from the viewpoint of suppression of wear, etc., and its surface roughness is as small as possible (less than 1S)
However, when the surface roughness is reduced in this way, stick-slip is likely to occur. On the other hand, if the surface roughness is excessively large, the wear of the seal groove and the lip will be accelerated. In the sealing device of the present invention, since the surface roughness of the seal groove is 1S or more,
The stick-slip phenomenon can be prevented. On the other hand, since the surface roughness of the seal groove is set to 6S or less, wear of the seal groove and the lip does not pose a problem.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a ball bearing will be described below with reference to FIGS.

As shown in FIG. 1, the ball bearing includes an inner ring (1), an outer ring (2), a plurality of balls (not shown) interposed between the inner and outer rings (1) and (2), and the balls are arranged at equal intervals. The holding device (3) comprises a sealing device (5) disposed at both ends of a gap between the inner and outer rings (1) and (2).

The sealing device (5) is composed of a seal body (6) made of a synthetic rubber material or the like and a metal core (7) for reinforcing the seal body (6). The outer ring (2) is fitted in mounting grooves (8) provided in the inner diameter portions at both ends.

At the inner diameter end of the seal body (6), a contact piece (10) whose inner diameter is inclined toward the outside of the bearing is provided with a contact piece (1).
A lip (12) composed of a vertical portion (11) integrally formed on the outer ring side (outer diameter side) of (0) is provided. The vertical part (11)
The contact piece (10) has a thickness substantially equal to that of the contact piece (10) and is formed in an annular shape in the radial direction. In this embodiment, the contact piece (10)
Is inclined toward the outside of the bearing, but may be inclined toward the retainer (3).

A seal groove (14) is formed in the outer diameter portion at both ends of the inner ring (1). The seal groove (14) is composed of a seal surface (15) substantially parallel to the outer diameter surface of the inner ring (1) and a tapered surface (16) that forms a downward slope toward the outside of the bearing. Among them, at least the sealing surface (15) is polished to have a surface roughness of about 1S to 6S (0.2a to 1.0a), unlike the conventional mirror finish.

The contact surface (15) of the lip (12) is in contact with the sealing surface (15). That is, this sealing device (5)
Is a radial contact type in which the lip (12) is brought into contact with the seal groove (14) from the radial direction.

As described above, according to the present invention, the lip (12) is brought into contact with the seal groove (14) from the radial direction,
A vertical portion (11) extending in the radial direction is provided on a part of the lip (12) and on the outer ring (2) side of the contact piece (10),
In addition, since the surface roughness of the sealing surface (15) that is in sliding contact with the contact piece (10) of the lip (12) is set to about 1S to 6S (0.2a to 1.0a), the noise caused by stick-slip can be reduced. Generation can be prevented. In addition, since the rigidity of the lip (12) is enhanced by providing the vertical portion (11) extending in the radial direction, the elasticity of the lip (12) does not decrease with the enhancement of the rigidity, and the sealing function decreases. Also, there is no possibility of causing troubles such as an increase in shaft torque.

In the above description, the present invention is applied to a ball bearing. However, the present invention is widely applicable to rolling bearings in general regardless of the inner ring rotating type and the outer ring rotating type. The same effect can be obtained by fitting the seal body (6) to the inner ring (1) and sliding the lip (12) into the seal groove provided in the outer ring (2).

[0021]

As described above, according to the present invention, it is possible to avoid the stick-slip phenomenon which occurs at the sliding contact portion between the lip and the raceway, and it is possible to prevent the generation of unpleasant squeak noise caused by this with a simple structure. Can be prevented.

In order to confirm this effect, a conventional axial contact type sealing device (FIG. 3A) and a sealing device according to the present invention (a radial contact type sealing device having a vertical portion (11):
1 (see FIG. 1), the outer ring was rotated to perform an experiment to determine whether or not squealing noise was generated.
The result shown in FIG. Among them, FIG. 7A shows an experimental result of a conventional axial contact type sealing device (seal groove surface roughness = 1 s), and FIG. 7B shows an experimental result of a sealing device according to the present invention. (Seal groove surface roughness =
3s).

From the experimental results, it can be seen that in the sealing device of the present invention, the squealing noise can be reliably eliminated within the range of the rotation speed n = 2000 to 7000 rpm and the bearing temperature of 30 to 140 ° C. It can be understood that the apparatus generates a squeal even under the same conditions.

In FIG. 2B, the data of the seal degreasing product (indicated by △) is also shown in FIG.
This is because if the oil is present in 4), the slip is improved and stick-slip hardly occurs, and the effect of suppressing stick-slip cannot be correctly evaluated.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention.

FIG. 2 is a graph showing the results of a comparative experiment between a conventional sealing device and the sealing device according to the present invention.

3A and 3B are cross-sectional views showing a conventional sealing device, in which FIG. 3A shows an axial contact type sealing device, and FIG. 3B shows a radial contact type sealing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 5 Sealing device 6 Seal body 10 Contact piece 11 Vertical part 12 Lip 14 Seal groove 15 Seal surface

Claims (1)

(57) [Claims] 1. A sealing device for a bearing having a lip slidingly contacting a seal groove provided on one raceway, wherein the lip contacts the seal groove from a radial direction,
A vertical portion extending in the radial direction is provided on a part of the lip and on the other raceway side than the sliding contact portion with the raceway,
A bearing sealing device wherein the surface roughness of the seal groove is set to 1S to 6S.