JP2003148626A - Seal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in a conventional seal device for a wheel or rolling bearing device that a large rotating torque is required for the rotation of an inner ring member since a lip of elastic seal body is in contact with a metal ring, the friction force between the lip and the metal ring works in the rotation of the inner ring member, and is added to the rotating friction torque. SOLUTION: The value of surface roughness Rz of the metal ring 8B is set to 1.50-3.00 μm, whereby the rotating friction torque in the rotation of an outer ring member 2 around an axis in the state where the elastic seal body 11B (lip 10) is in contact with the metal ring 8B is significantly reduced, compared with a conventional case. Necessary sealing property is also ensured.

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 sealing an annular bearing space between an outer ring member and an inner ring member in a wheel rolling bearing.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 1, a rolling bearing device 1 for a wheel has an outer ring member 2 supported non-rotatably on the vehicle body side, and a double row of balls 3 mounted on the outer ring member 2. And an inner ring member 5 that is rotatably supported about an axial center 4, and both sides of the annular bearing space 6 for enclosing a lubricant in the annular bearing space 6 between the outer ring member 2 and the inner ring member 5. The sealing device 7A,
Some are sealed with 7B.

As shown in FIG. 2, a sealing device 7B on the vehicle inner side of the sealing device 7 includes a core metal 9B fitted on the inner peripheral surface of the outer ring member 2 and an outer peripheral surface of the inner ring member 5. It is composed of a metal ring 8B (slinger) fitted and a synthetic rubber elastic seal body 11B fixed to the core metal 9B and having lips 10c and 10d for contacting the metal ring 8B.

[0004]

In the above sealing device 7,
The lips 10c and 10d of the elastic seal body 11B are metal rings 8B.
When the inner ring member 5 of the rolling bearing device 1 rotates around the shaft center 4, the lip 10c,
The frictional force between 10d and the metal ring 8B acts when the inner ring member 5 rotates.

Therefore, in order to reduce the rotational friction torque for rotating the inner ring member 5 around the axis 4, it is necessary to reduce the frictional force between the lips 10c and 10d and the metal ring 8B.

In order to solve this, it can be considered to increase the surface roughness of the metal ring 8B. By doing so, the frictional force between the lips 10c, 10d and the metal ring 8B is reduced, and the rotational friction torque can be reduced. However, if the surface roughness of the metal ring 8B is large, on the contrary, the lip 1
The wear of 0c and 10d is promoted and the sealing property of the sealing device 7B is deteriorated.

Therefore, an object of the present invention is to provide a sealing device which can solve the above problems.

[0008]

In order to solve the above-mentioned problems, a sealing device according to the present invention is provided with an outer member and an inner member which are provided so as to be rotatable relative to each other around a coaxial center and which are arranged via an annular space. And a resin sealing member that is disposed between the outer member and the inner member, and has a resin sealing member that is in contact with the outer member and the inner member. The ten-point average roughness of the contact surface of the other member with which the seal member contacts is set to 1.50 μm to 3.00 μm.

By setting the ten-point average roughness of the contact surface with which the seal member contacts in this way to 1.50 μm to 3.00 μm, the seal member can be made to surround the periphery of any one of the outer member and the inner member. The rotational friction torque when the outer member and the inner member relatively rotate about the axis in a state of being in contact with the surface is significantly reduced, and necessary sealing property is secured.

Further, one member of the outer member and the inner member is disposed between an outer member and an inner member that are rotatably provided around a coaxial center and are disposed via an annular space. Has a sealing member made of resin in contact with a metal ring fitted to the peripheral surface of the other member of the outer member and the inner member, and ten points of contact surfaces of the metal ring contacting the sealing member. The average roughness is set to 1.50 μm to 3.00 μm.

Thus, the ten-point average roughness of the contact surface with which the seal member contacts is set to 1.50 μm to 3.00 μm, so that the outer member and the inner member are in contact with the metal ring. The rotational friction torque when the and are relatively rotated about the axis is significantly reduced, and the necessary sealing property is secured.

The metal ring is formed by rolling and rolling the metal plate so that the surface ten-point average roughness thereof is in the region of 1.50 μm to 3.00 μm, and is formed into an L-shaped cross section by pressing. Since the metal ring is fitted on the peripheral surface of the other member, it is compared with the case where the metal ring is formed on the peripheral surface of the other member so that the value of the surface roughness of the metal ring becomes a predetermined region. As a result, manufacturing becomes easier and productivity is improved.

Further, even in the structure in which the outer member and the inner member are the outer ring member of the bearing device and the inner ring member disposed on the outer ring member via the rolling elements, respectively, the seal member is in contact with the metal ring. In this state, the rotational friction torque when the outer member and the inner member relatively rotate about the axis is significantly reduced, and the necessary sealing property is secured.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A sealing device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall sectional view of a rolling bearing device for a wheel having a sealing device, and FIG. 2 is an enlarged sectional view of the sealing device.

1 and 2 are used as common drawings for the conventional rolling bearing device 1 for wheels and the sealing device 7.

First, the entire structure of the rolling bearing device for a wheel 1 will be described. This is an outer ring member (an example of an outer member) which is non-rotatably supported by a knuckle (not shown) on the vehicle body side.
2 and the inner ring member (2) rotatably supported on the outer ring member 2 around the axis 4 via two rows of balls (rolling elements) 3 held at equidistantly circumferential positions by a crown-shaped cage 15. An example of the inner member) 5.

The inner ring member 5 is a member different from the hub wheel 16 for mounting wheels (brake disc rotor and tire wheel) and the hub wheel 16 fitted on the vehicle inner side outer peripheral surface of the hub wheel 16. It is composed of an annular body 17. A mounting flange (hub flange) 18 that projects outward in the radial direction is formed on the outer peripheral surface of the portion of the hub wheel 16 that projects from the outer ring member 2 toward the vehicle outer side.
Mounting bolts (hub bolts) 19 for fixing the brake disc rotor and the tire wheel in an overlapping manner are press-fitted at predetermined positions in the circumferential direction. The hub wheel 16 has a central hole 20 through which the power transmission shaft is inserted.

Next, the annular bearing space 6 between the outer ring member 2 and the inner ring member 5 is hermetically sealed on both sides thereof to seal the annular bearing space 6 with a lubricant and prevent muddy water from entering from the outside. The sealing device 7 for this will be described. This sealing device 7
Comprises an outer side sealing device 7A and an inner side sealing device 7B.

The outer side sealing device 7A includes an outer ring member 2
9A that is fitted to the outer circumferential surface of the outer side of the
An elastic seal body 11A fixed to the outer peripheral surface of the hub wheel 16 and having a radial lip 10a that makes radial contact with the continuous portion of the mounting flange 18 and an axial lip 10b that makes contact with the side surface of the mounting flange 18 in the axial direction; It consists of

The inner sealing device 7B has a core metal 9B fitted to the inner peripheral surface of the outer ring member 2 and the outer peripheral surface of the annular body 17, as shown in FIG. A metal ring 8B having an L-shaped cross section and fitted to the core metal 9B
And an elastic seal body 11 having a lip 10 fixed to the sliding contact surface of the metal ring 8B facing the cored bar 9B. The lip 10 is composed of a radial lip 10c that contacts the fitting portion of the metal ring 8 in the radial direction and an axial lip 10d that contacts the rising surface of the metal ring 8 in the axial direction.

As a material for the metal ring 8B, JIS.
Stainless steel such as SUS430 and 304 is used.

By the way, in the above sealing device 7, particularly the inner sealing device 7B, the radial lip 10c and the axial lip 10d of the elastic seal body 11B are in contact with the metal ring 8, respectively. When the inner ring member 5 rotates about the axis 4, the frictional force of the metal ring 8 acts. Therefore, in order to reduce the rotational torque that tends to rotate the inner ring member 5 around the axis 4, it is necessary to adjust the surface roughness of the metal ring 8B to reduce the frictional force. This can be realized by reducing the friction coefficient f of the metal ring 8B.

It is known that the friction coefficient f has a relationship with the dimensionless characteristic number G representing the operating condition, as shown in the following equation (1).

F = φ · G ^1/3 (1) The dimensionless characteristic number G is expressed by G = μ · u · b / P. Here, μ: oil (lubricant) viscosity, u: shaft (metal ring 8B) peripheral speed, b: seal contact width (lip 10c, 1
0d contact width), P: tightening force (sum of contact loads of lips 10c, 10d). Further, φ is a coefficient showing the sealing property, and the following equation φ = 5 (hmax / λ) ^2/3 (D / 2 · hmax) ^1/3
It is represented by xexp (α · p · j · λ / hmax). Where hma
x: Shaft surface roughness (hereinafter referred to as Rz because it is equivalent to the ten-point average roughness of the surface of the metal ring 8B), λ: wavelength of roughness, D: shaft diameter (diameter of the metal ring 8), α: constant, p: Contact surface pressure (value obtained by dividing the pressing force by the contact area), j: Elastic seal body (lip 10
c, 10d) is the real part of the complex elastic modulus.

When the shape of the elastic seal body 11B, its material (synthetic rubber) and its surface roughness (wavelength) are the same and only the roughness of the sliding surface of the metal ring 8B is changed, the above coefficient φ is obtained. Is known to have the following relationship with the axial roughness Rz.

Φ ∝ β [= Rz ^1/3 xexp (1 / Rz)] In the following (Table 1), Rz values and β values obtained for each Rz value based on the above equation, Conventional (current) R
The value of z: The ratio of the value of β to 3.89 in the case of 0.67 μm and the value of β obtained from each Rz is shown.

[0027]

[Table 1] From the above (Table 1), it can be seen that in the region where the Rz value is 3.00 μm, the β value decreases as the Rz value increases. By the way, when the value of Rz becomes 3.00 μm or more, R
It can also be seen that the value of β increases as the value of z increases.

By the way, in the above (Table 1), Rz is
In the case of 1.50 to 7.00 μm, the value of conventional (current) Rz is 0.67 μm
Since the value of β is calculated to be reduced by about 40% as compared with m, it is estimated that the friction torque is also reduced by about 40%.

Considering such a reduction of the value of β as a reference, the value of Rz is appropriate to be 1.50 to 7.00 μm. On the other hand, when the value of Rz is large, the elastic seal body 11 and the metal ring 8 come into contact with each other. It is conceivable that the sealing property of the (sliding) part is reduced.

Here, the following (Table 2) shows the values of the rotational friction torque obtained by an experiment in which Rz was changed and other sealing conditions were the same.

[0031]

[Table 2] The rotational friction torques in the Rz value range of 1.00 μm or more, especially in the range of 1.50 to 3.00 μm, show almost the same values, and this rotational friction torque is reduced by about 30% compared to the current product. But it was also proved by experiments.

Further, an experiment for knowing the limit value of the value of Rz for maintaining a predetermined hermeticity was conducted by using an apparatus as shown in FIG. That is, the elastic seal body 31 is attached to the core metal 30,
The lip 32 of the elastic seal body 31 is brought into contact with the surface of a shaft body 33 (corresponding to the metal ring 8B) having different Rz values, and the lip body 32 is rotated around the shaft center for a predetermined time. The wear width γ mm of the The conditions in this test are as follows.

Lubricant: ATF oil (Dexylon II), shaft diameter: 35 mm, shaft rotation speed: 4000 / min, shaft eccentricity: 0.1 mmTI
R, shaft rotation time: 504h.

The test results of this experiment are shown below (Table 3).

[0035]

[Table 3] From the above (Table 3), the value of the wear width γ is good (small)
It can be seen that the value of Rz is in the region of 1.00 to 3.00 μm.

From the above experimental results, it is considered appropriate that the value of Rz is in the range of 1.50 to 3.00 μm in consideration of the rotational friction torque and the sealing property.

In the above (Table 3), the value of Rz is
The value of the wear width γ increases at 0.80 μm or less because the smoothness of the surface of the shaft body 33 becomes too high and the lubricant is hard to be retained on the surface, the lubricity deteriorates and wear progresses. Is considered to be.

By the way, in the embodiment of the present invention,
The metal ring 8 is formed by pressing into an L-shaped cross section. Prior to this pressing, a plate material to be the metal ring 8 is formed by rolling with a roller. During this rolling, the surface roughness Rz of the plate material is 1.50 to 3.00 μm.
It is manufactured by transferring with the roller so that it becomes the area of. By doing so, as compared with the case where the metal ring 8 is formed so as to have a surface roughness Rz in the range of 1.50 to 3.00 μm after the press working, the manufacturing becomes easier and the productivity is improved.

As described above, in the embodiment of the present invention,
By setting the value of the surface roughness Rz of the metal ring 8 to 1.50 to 3.00 μm, the elastic seal body 11 (lip 10c, 10
The rotational friction torque when the outer ring member 2 rotates around the shaft center 4 in the state where d) is in contact with the metal ring 8 can be significantly reduced as compared with the conventional case, and the necessary sealing performance can be secured.

The present invention is not limited to the above embodiment, and various modifications and applications can be considered within the scope of the present invention.

For example, in the above embodiment, the sealing device 7
The case of the inner side sealing device 7B has been described above, but the present invention is not limited to this, and is applicable to the outer side sealing device 7A. In this case, the surface roughness Rz of the continuous portion of the outer peripheral surface of the hub wheel 16 and the mounting flange 18 is
It is formed to have a region of 1.50 to 3.00 μm. By doing so, the rotational friction torque when the outer ring member 2 rotates around the axis 4 in a state where the elastic seal body 11 (the lips 10a, 10b) is in contact with the continuous portion, as in the above-described embodiment, Compared with the conventional case, it can be greatly reduced and the required sealing performance can be secured.

By applying the present invention to both the outer side sealing device 7A and the inner side sealing device 7B, it is possible to further reduce the rotational friction torque while ensuring a predetermined sealing performance.

Further, the wheel rolling bearing device 1 to which the sealing device 7 of the above embodiment is applied is not limited to the above embodiment.

For example, in the wheel rolling bearing device 1 shown in FIG. 4, the inner ring member 5 is supported non-rotatably on the vehicle body side, and the outer ring member 2 is rotated around the axis 4 via the balls 3 in two rows. A sealing device 7 that is rotatably supported and that seals the annular bearing space 6 between the outer ring member 2 and the inner ring member 2 on the vehicle inner side.
Is provided.

The sealing device 7 has the same structure as that of the inner sealing device 7B described above, but is different from the above-described embodiment in that a cored bar fitted to the inner peripheral surface of the outer ring member 2 is fitted. 9B and the elastic seal body 11B having a lip that contacts the sliding contact surface of the metal ring 8B fixed to the outer peripheral surface of the inner ring member 2 and fixed to the core metal 9B rotate, and the metal ring 8B does not rotate. It is a point. Also in the sealing device 7 (7B) having this configuration, the surface roughness R of the metal ring 8B is the same as in the above embodiment.
The value of z is set to 1.50 to 3.00 μm.

Further, the wheel rolling bearing device 1 shown in FIG.
Is an outer ring member 2 supported non-rotatably on the vehicle body side, and a hub wheel 16 and a bowl-shaped outer ring member 40 of a constant velocity joint are rotatably supported on the outer ring member 2 via balls 3 about an axis 4. ing. An annular bearing space 6 formed by the outer ring member 2 and the hub wheel 16 and the bowl-shaped outer ring member 40.
The outer sealing device 7A and the inner sealing device 7B are provided as the sealing device 7 for sealing the cores 9A and 9B with the elastic seal bodies 11A and 11B fitted to the inner peripheral surface of the outer ring member 2, respectively. Attached to the elastic seal bodies 11A, 11
B is a radial lip and an axial lip (reference numeral omitted)
And each of these elastic seal bodies 11A, 11
The lip B is in direct contact with the outer peripheral surfaces of the hub wheel 16 and the bowl-shaped outer ring member 40.

In this structure, the surface roughness Rz of the contact portion of the hub wheel 16 and the bowl-shaped outer ring member 40 where the radial lip and the axial lip come into contact with each other is 1.50 to 3.0.
It is set to 0 μm.

By doing so, the rotational friction torque when the outer ring member 2 rotates about the shaft center 4 with the elastic seal bodies 11A and 11B in contact with the contact portions is the same as in the above-described embodiment. Compared with the case of 1, the required sealing performance can be secured.

In each of the above embodiments, the rolling bearing device for the wheel using the two rows of balls 3 is shown as an example of the rolling element, but the rolling bearing device is not limited to this, and although not shown, the rolling element is not shown. Of course, the present invention can be applied to a rolling bearing device for a wheel using rollers as a moving body, and by setting the value of Rz of the contacting portion of the lip to be 1.50 to 3.00 μm, the same effect as the above embodiment can be obtained. Can play.

[0050]

As apparent from the above description, according to the present invention, in order to seal the annular space between the outer member and the inner member, one of the outer member and the inner member is provided on the peripheral surface of one member. Having a resin sealing member in contact with the peripheral surface of the other member, since the ten-point average roughness of the contact surface of the other member contacting the sealing member is set to 1.50 μm to 3.00 μm, The rotational friction torque when the seal member comes into contact with the contact portion of the other member and the outer member and the inner member relatively rotate around the axis while ensuring the necessary sealing performance as the sealing device is significantly increased. Can be reduced.

Further, the ten-point average roughness of the contact surface of the metal ring fitted to the peripheral surface of the other member with which the seal member contacts is 1.50.
Since it is set to μm to 3.00 μm, the rotational friction when the outer member and the inner member rotate relative to each other around the axis with the seal member contacting the metal ring while ensuring the necessary sealing performance Torque can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing an overall configuration of a rolling bearing device for a wheel showing an embodiment of the present invention.

FIG. 2 is likewise an enlarged sectional view of a main part.

FIG. 3 is an experimental diagram for knowing a limit value of Rz value for maintaining a predetermined hermeticity.

FIG. 4 is a cross-sectional view showing an overall configuration of a rolling bearing device for a wheel according to another embodiment.

FIG. 5 is a cross-sectional view showing an overall configuration of a wheel rolling bearing device according to yet another embodiment.

[Explanation of symbols] 1 Rolling bearing device for wheels 2 Outer ring member 5 Inner ring member 6 Annular bearing space 7 Sealing device 7A Outer side sealing device 7B Inner side sealing device 8B metal ring 9B core 10 lips 10c radial lip 10d axial lip 16 hub wheels 18 Mounting flange

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshinori Masuda             3-5-8 Minamisenba, Chuo-ku, Osaka Koyo             Within Seiko Co., Ltd. F-term (reference) 3J006 AD02 AE23 AE45 AF01 CA03                 3J016 AA01 BB03 CA02                 3J101 AA02 AA43 AA54 AA62 BA53                       BA54 FA13 FA41 GA03

Claims (4)

[Claims] 1. A member of one of the outer member and the inner member, which is disposed between an outer member and an inner member and is provided rotatably around a coaxial center and is disposed via an annular space. A sealing device for sealing the annular space, having a resin sealing member in contact with the peripheral surface of the other member of the outer member and the inner member on the peripheral surface of the other member. A ten-point average roughness of a contact surface of the sealing member, which is in contact with the sealing member, is set to 1.50 μm to 3.00 μm. 2. A member of one of the outer member and the inner member, which is arranged between an outer member and an inner member and is provided so as to be relatively rotatable about a coaxial center and is arranged via an annular space. A sealing device for sealing the annular space, having a resin sealing member in contact with a metal ring fitted to the peripheral surface of the other member of the outer member and the inner member on the peripheral surface thereof. A sealing device, wherein a ten-point average roughness of a contact surface of the metal ring contacting the seal member is set to 1.50 μm to 3.00 μm. 3. The metal ring is formed by roller-transferring and rolling the metal plate so that the surface ten-point average roughness of the metal plate is in the region of 1.50 μm to 3.00 μm, and is formed into an L-shaped cross section by pressing. The sealing device according to claim 2, wherein the sealing device is fitted on the peripheral surface of the other member. 4. The outer member and the inner member are an outer ring member of a bearing device and an inner ring member disposed on the outer ring member via rolling elements, respectively.
The sealing device according to claim 3.