JP2003269617A - Seal device, rolling bearing incorporated therewith and hub unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve following-up performance to a motion of a slinger 6 of a middle seal lip 15 located in the middle among three seal lips 14a, 15b, 16, and to sufficiently secure sealability for a long period of time. <P>SOLUTION: The thickness of the middle seal lip 15b is gradually decreased as it goes from the base end part to the middle part and increased as it goes from the middle part to the tip end part. The thickness of the middle seal lip 15b is made to be the maximum at a part of near the tip end part. The thickness of the base end part of the middle seal lip 15b is set to d<SB>1</SB>, and the thickness of the minimum thickness part of the thickness at the middle part is set to d<SB>2</SB>. The area of the part covering the minimum thickness part from the base end part is set to S<SB>1</SB>in the section related to the axial direction of the middle seal lip 15b, and the area covering the tip end edge from the part of the minimum thickness is set to be S<SB>2</SB>. In this case, 0.80d<SB>1</SB>≤d<SB>2</SB>≤0.98d<SB>1</SB>and 0.1S<SB>2</SB>≤S<SB>1</SB>≤0.5S<SB>2</SB>are satisfied. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The sealing device, the rolling bearing and the hub unit according to the present invention relate to an improvement of a rolling bearing and a hub unit sealing device incorporated in a rotation supporting portion such as a supporting device of an automobile wheel.

[0002]

2. Description of the Related Art Ball bearings,
Rolling bearings such as cylindrical roller bearings and tapered roller bearings are incorporated. A sealing device is incorporated in such a rolling bearing to prevent the grease enclosed in the rolling bearing from leaking to the outside, and to prevent rainwater existing outside.
It prevents various foreign substances such as mud and dust from entering the inside of the rolling bearing. 8 to 10 show two examples of the conventional structure of the sealing device mounted on the end opening of the rolling bearing for such a purpose.

First, the sealing devices 17 and 17 of the first example of the conventional structure shown in FIGS. 8 to 9 are disclosed in Japanese Patent Application Laid-Open No. 10-252762, and include a core metal 5 as a holding member and a slinger. 6 and a sealing material 7. 5 of these
Is an outer diameter side cylindrical portion 9 that can be internally fitted and fixed on the inner peripheral surface of the end portion of the outer ring 8, and an axial inner end edge of the outer diameter side cylindrical portion 9 (an end edge of the rolling bearing 1 near the center in the axial direction, Cross section L including inner ring portion 10 bent inward in the diametrical direction from the left end edge of 9)
The whole shape is ring-shaped. In addition, the above slinger 6
9 is an inner diameter side cylindrical portion 12 that can be externally fitted and fixed to the outer peripheral surface of the end portion of the inner ring 11, and an axial outer end edge of the inner diameter side cylindrical portion 12 (an edge near the axial opening of the rolling bearing 1; The outer ring portion 13 is bent outward in the diametrical direction from the right end edge) and has an annular shape with an L-shaped cross section. The sealing material 7 is made of an elastic material such as elastomer such as rubber, and has three sealing lips 14 to 16 on the outside, middle and inside.
And a base end portion thereof is coupled and fixed to the core metal 5.
Then, the tip edge of the outermost outer lip 14 is slidably contacted with the inner side surface of the outer ring portion 13 constituting the slinger 6, and the remaining two seal lips, the intermediate seal lip 15 and the inner seal. The tip edge of lip 16
It is slidably in contact with the outer peripheral surface of the inner diameter side cylindrical portion 12 constituting the slinger 6.

Further, in the case of the first example of the conventional structure shown in FIGS. 8 to 9, the three seal lips 14 provided on the sealing material 7 are used.
Outermost outer seal lip 1
The thickness of No. 4 is gradually reduced from the base end portion toward the tip end edge. Also, the innermost seal lip 1 located on the innermost side
The thickness of 6 is also gradually reduced from the base end toward the tip edge. Further, the inner seal lip 16 is inclined toward the axially outer side of the rolling bearing as it goes toward the tip edge. Further, an intermediate seal lip 15 located in the middle, which corresponds to the radial seal lip described in the claims.
Has a substantially equal thickness over the entire length at the intermediate portion excluding the base end portion and the tip edge.

The sealing device 17 as described above is provided in the rolling bearing 1
Used by incorporating into the end of. Rolling bearing 1 shown in FIG.
In the case of, the inner ring raceway 1 is formed on the outer peripheral surface of the pair of inner rings 11, 11.
8 and 18 are formed, and a pair of outer ring raceways 19 and 1 are formed on the inner peripheral surface of the outer ring 8 provided around these inner rings 11 and 11.
9 is formed. And, each of these outer ring raceways 19, 1
A plurality of rolling elements 20, 20 are rotatably incorporated between the inner ring raceway 9 and the inner ring raceways 18, 18.

Also, in the case of the sealing device 17a of the second example of the conventional structure shown in FIG. 10, it has substantially the same structure as the structure of the first example shown in FIGS. Particularly, in the case of this example, among the three seal lips 14a, 15a, 16
The thickness of the outermost sealing lip 14a is
The total length from the base end to the tip edge is almost the same.
Also, corresponding to the radial seal lip described in the claims,
The thickness of the intermediate seal lip 15a located in the middle is gradually increased (thickened) from the base end portion to the intermediate portion, and is rapidly increased in the portion near the tip end, and further reduced (thinner) in the vicinity of the tip end edge. ing. Further, the thickness of the intermediate seal lip 15a is made smallest at the base end portion. or,
In a cross section about an imaginary plane including the central axis of the intermediate seal lip 15a, the area of the intermediate portion of the intermediate seal lip 15a from the portion where the thickness abruptly changes to the base end portion is S _1, and this thickness is Is regulated so that S ₁ <S ₂ is satisfied, where S ₂ is the area from the abruptly changing portion to the leading edge. In addition, FIG. 10 shows a state before the core metal 5 and the sealing material 7 and the slinger 6 are combined,
The sealing material 7 and the slinger 6 are shown in a state where they are partially overlapped with each other in a free state, and do not show a state before or after actual combination.

In each of the first and second examples of the conventional structure as described above, the seal lips 14, 14a provided on the respective seal members 7,
By sliding the leading edges of 15, 15a, 16 and the slinger 6 in sliding contact, the end opening of the rolling bearing 1 (FIG. 8) is closed.
The grease sealed inside the rolling bearing 1 is prevented from leaking to the outside, and various foreign substances such as rainwater, mud, dust, etc. existing outside are prevented from entering the inside of the rolling bearing.

[0008]

In the two examples of the conventional structure shown in FIGS. 8 to 10, it is desired to improve the following points. That is, two examples of these conventional structures are
For example, when it is used for the rolling bearing 1 incorporated in a support device for a vehicle wheel, and when the vehicle makes a sharp turn, the inner ring 11 on which the slinger 6 is fitted and the outer ring 8 on which the core metal 5 is fitted are There is a possibility that they are relatively inclined (the central axes of both members 11, 8 do not match). In this way, both inner and outer wheels 11, 8
Is relatively inclined, the slinger 6 and the cored bar 5 come close to each other, and the seal lips 14, 14a,
15, 15a, 16 are over-compressed. Further, even if the inner ring 11 is eccentric with respect to the outer ring 8 for some reason, the seal lips 14, 14a, 15, 15a, 16 may be excessively compressed. In this way each seal lip 1
If 4, 14a, 15, 15a, 16 are over-compressed, their respective sealing lips 14, 14a, 15, 15
The so-called tightening force, which is the force with which the leading edges of a and 16 are pressed against the slinger 6, increases. Therefore, the tip edges of the seal lips 14, 14a, 15, 15a, 16 are easily worn, and the seal lips 14, 14a, 1
The sealing performance at the sliding contact portion between the leading edges of 5, 15a, 16 and the slinger 6 deteriorates. Further, in this case, the rotation torque of the rolling bearing 1 becomes large.

When the inner and outer wheels 11 and 8 are inclined relative to each other or the inner ring 11 is eccentric with respect to the outer ring 8, the circumferential surfaces of the both wheels 11 and 8 are located on the opposite side to the above portion in the radial direction. Therefore, since the seal lips 14, 14a, 15, 15a, 16 present on the opposite side portions become less strict, the rainwater and the like easily enter the inside of the sealing devices 17, 17a. On the other hand, the seal lip 14,
By increasing the initial tightening margins of 14a, 15, 15a, 16 it is possible to prevent the tightening force from being insufficient at the opposite side portion. However, in this case, due to the relative inclination between the inner and outer wheels 11 and 8, the seal lips 14, which are present on the peripheral surface portions approaching each other,
The tightening force of 14a, 15, 15a, 16 is further increased. Therefore, these seal lips 14, 14a, 1
The tip edges of 5, 15a and 16 are further worn, and the sealing performance is further deteriorated. Further, the rotating torque of the rolling bearing 1 is further increased.

In particular, in the case of the first example of the conventional structure shown in FIGS. 8 to 9, of the plurality of seal lips 14, 15, 16
The thickness of the intermediate seal lip 15 located in the middle is approximately equal over the entire length in the intermediate portion excluding the base end portion and the tip edge. Therefore, when both the inner and outer wheels 11 and 8 are relatively inclined or the inner ring 11 is eccentric with respect to the outer ring 8, the tip edge of the intermediate seal lip 15 against the movement of the surface of the slinger 6. Hard to follow. Therefore, a part of the intermediate seal lip 15 is apt to have an excessive tightening force, and a part opposite to this part in the radial direction tends to have an excessively small tightening force.

On the other hand, in the case of the second example of the conventional structure shown in FIG. 10, the thickness of the intermediate seal lip 15a is gradually increased from the base end portion toward the intermediate portion, and is rapidly increased at the tip end portion. It is big. Furthermore, in cross-section about the virtual plane including the central axis of the intermediate seal lip 15a, the area S ₂ of the distal end portion closer is made larger than the area S ₁ of the proximal end portion near (S _2> S _1). Therefore, the second of the conventional structure
In the case of the example, even if both the inner and outer wheels 8 and 11 are relatively inclined or the inner ring 8 is eccentric with respect to the outer ring 11, the tip edge of the intermediate seal lip 15a moves on the surface of the slinger 6. On the other hand, it becomes easier to follow up than in the case of the first example of the conventional structure. However, in the case of the second example of the above-mentioned conventional structure, the thickness of the intermediate seal lip 15a is made smallest at the base end portion. Therefore, the core metal 5 and the sealing material 7
With the combination of the slinger 6 and the slinger 6, a large strain is likely to occur at the base end portion of the intermediate seal lip 15a. When such a large strain is generated, the base end portion is apt to cause fatigue (reduction in elasticity) due to stress. Therefore, the above-mentioned intermediate seal lip 15a may be used for a long period of time.
And the sealing performance of the sealing device 17a is likely to deteriorate. In view of such circumstances, the present invention has been made in order to improve the followability of the radial seal lip with respect to the movement of the peripheral surface of the other side and to sufficiently secure the sealability for a long period of time. .

[0012]

Among the sealing device, the rolling bearing and the hub unit of the present invention, the sealing device according to claim 1 is provided on the inner ring raceway provided on the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring. A plurality of rolling elements are provided between the outer ring raceway and the outer ring raceway and incorporated into a rolling bearing that allows relative rotation of the inner ring and the outer ring, and the space between the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring is closed. . For this reason, the sealing device of the present invention includes a holding member, a sealing material, and a radial seal lip, as in the first and second examples of the conventional structure shown in FIGS.
The holding member is fixed to one of the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring. The sealing material is made of an elastic material, and a part of the sealing material is fixedly connected to the holding member. Further, the radial seal lip is provided in a part of the sealing material, and the tip edge thereof is
The outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring are slidably contacted with the radially-oriented circumferential surface provided on the other or the radially-oriented circumferential surface of a member supported by the other.

Particularly, in the sealing device according to the first aspect of the present invention, the thickness of the radial seal lip decreases from the base end portion toward the middle portion, and the portion extending from the middle portion to the tip edge is formed. Is thicker than the thickness of the portion extending from the base end portion to the intermediate portion. Further, the thickness of the radial seal lip is maximized in a part of the portion extending from the intermediate portion to the tip edge. Then, the thickness of the proximal end portion of this radial seal lip is d ₁ , the thickness of the minimum thickness portion where the thickness is the minimum in the middle portion is d _2, and the virtual axis including the center axis of this radial seal lip is assumed. In the cross section about the plane, the area from the base end portion to the minimum thickness portion is S ₁
When the area of the portion extending from the minimum thickness portion to the tip edge is S ₂ , 0.80d ₁ ≦ d ₂ ≦ 0.98d ₁
And 0.1S ₂ ≦ S ₁ ≦ 0.5S ₂ are satisfied.

A rolling bearing according to a second aspect of the present invention incorporates at least one sealing device according to the first aspect. The hub unit described in claim 3 is a hub for fixing a wheel to an inner ring or an outer ring, and incorporates at least one sealing device described in claim 1.

[0015]

The sealing device and rolling device of the present invention having the above-described structure
The bearing and hub unit can be used to
And the followability of the radial seal lip provided on the seal material.
In addition to being good, it ensures sufficient sealing performance over a long period of time.
You can That is, in the case of the sealing device of the present invention, this diameter
Section about an imaginary plane including the central axis of the directional seal lip
Then, the area S of the portion near the base end₁ Is the area S near the tip
₂ 0.5 times or less. Therefore, when using, the inner ring
Is tilted or eccentric to the outer ring,
Part of the material and the surrounding surface of the other side approach or move away from each other.
Even if it does, the tip edge of the radial seal lip,
Follows the movement of the surrounding surface on the other side. Therefore,
It is possible to suppress the change in the tension force of the radial seal lip.
Wear. Therefore, wear of the tip edge of this radial seal lip
It is possible to obtain good sealing performance by suppressing
It is possible to suppress an increase in rolling torque. Furthermore, in the radial direction
Area S near the base end of the seal lip₁ The part near the tip
Area S of minutes ₂ Since it is 0.1 times or more of this, this radial direction
This radial seal while ensuring the durability of the seal lip
The lip and another seal next to this radial seal lip.
It is possible to prevent interference with the lip lip.

Further, in the case of the present invention, the thickness of the intermediate portion of the radial seal lip is made smaller than the thickness d ₁ of the base end portion, and the thickness of the intermediate portion at the minimum thickness portion is set. d
₂ is made slightly smaller than the thickness d ₁ of the base end portion. Therefore, the tip end edge of the radial seal lip is provided on the other of the outer peripheral surface of the inner ring or the hub and the inner peripheral surface of the outer ring in the radial direction or the member supported on the other. Prevents a large difference in the elastic deformation amount of the radial seal lip when it is in sliding contact with the circumferential surface facing the radial direction, and the stress applied to this radial seal lip is From the middle part can be almost equal. As described above, unlike the case of the second example of the conventional structure shown in FIG. 10 described above, excessive stress does not occur in a part of the radial seal lip, so that fatigue due to stress is less likely to occur. It is possible to secure sufficient sealing performance for a long period of time.

[0017]

1 and 2 show an example of an embodiment of the present invention. The sealing device 17b of the present invention includes a core metal 5 as a holding member, a slinger 6, and a sealing material 7a. The core metal 5 is integrally formed by subjecting a metal plate such as a low carbon steel plate to punching such as press working and plastic working. Such a cored bar 5 includes an outer diameter side cylindrical portion 9 that can be internally fitted and fixed to an inner peripheral surface of an outer end portion of an outer ring 8 (see FIG. 8) that constitutes the rolling bearing 1, and a shaft of the outer diameter side cylindrical portion 9. The inner circular ring portion 10 is bent inward in the diametrical direction from the inner edge in the direction (left edge in FIGS. 1 and 2), and has a substantially L-shaped cross section, and has an annular shape as a whole.

The slinger 6 is integrally formed by subjecting a metal plate having excellent corrosion resistance such as a stainless steel plate to punching such as press working and plastic working. Such a slinger 6 includes an inner diameter side cylindrical portion 12 which can be externally fitted and fixed to an outer end outer peripheral surface of an inner ring 11 (see FIG. 8) constituting the rolling bearing 1, and the inner diameter side cylindrical portion 1
A cross-section substantially L including an outer circular ring portion 13 that is bent outward in the diametrical direction from an axial outer end edge (right end edge in FIGS. 1 and 2) of FIG.
The whole shape is ring-shaped. Note that FIG. 1 shows a state before the core metal 5 and the sealing material 7 and the slinger 6 are combined. However, the figure shows a state in which the sealing material 7 and the slinger 6 are partially overlapped with each other in the free state, and does not show the state before the actual combination.

The seal member 7a is made of an elastic material such as an elastomer such as rubber and has three seal lips 14a, 15b and 16 on the outer side, the middle side and the inner side. The ends are fixed together. The tip end edge of the outermost outer seal lip 14a is slidably contacted with the inner side surface of the outer ring portion 13 forming the slinger 6, and the remaining two seal lips are the radial direction. Intermediate seal lip 15 corresponding to the seal lip
The tip edges of b and the inner seal lip 16 are brought into sliding contact with the outer peripheral surface of the inner diameter side cylindrical portion 12 constituting the slinger 6. Also, the above three seal lips 14, 15a, 16
All of a are inclined in a direction toward the outer side in the axial direction of the rolling bearing 18 toward the respective leading edges.

Further, in the case of the present invention, the thickness of the intermediate seal lip 15b is gradually reduced from the base end portion to the intermediate portion, and the thickness is minimized from the minimum thickness portion. The size increases sharply toward the tip.
Then, the thickness of the portion extending from this minimum thickness portion to the tip edge is made equal to or more than the thickness of this minimum thickness portion (more than the minimum thickness of the portion extending from the base end portion to this minimum thickness portion). ing. Further, the thickness of the intermediate seal lip 15b is maximized in the substantially central portion of the portion extending from the minimum thickness portion to the tip edge. And this intermediate seal lip 1
When the thickness of the proximal end portion of 5b is d ₁ and the thickness of the minimum thickness portion is d ₂ , 0.80d ₁ ≦ d ₂ ≦ 0.98d ₁
I try to meet. For example, the thickness d ₂ of the minimum thickness portion is set to 0.90 times the thickness d ₁ of the base end portion (d ₂ = 0.90d ₁ ). The thickness d ₁ of this base end portion
Is the thickness of the portion of the intermediate seal lip 15b that is located closest to the base end, excluding the corner R portion 25 having an arcuate cross section provided near the base end. In the case of this example,
The length L ₁ from the base end portion to the minimum thickness portion and the length L ₂ from the minimum thickness portion to the tip edge are made substantially equal (L ₁ ≈L ₂ ).

Further, in the case of the present invention, in the axial section of the intermediate seal lip 15b, from the base end portion having a thickness d ₁ to the minimum thickness portion having a thickness d _2. the area of over portion and S _1, the area of the portion over the leading edge from the minimum thickness portion when the S _2, 0.1S ₂ ≦
S ₁ ≦ 0.5S ₂ is satisfied. For example, the area S ₁ of the portion extending from the base end portion to the minimum thickness portion is
The area S ₂ from the minimum thickness portion to the tip edge is 0.3 times (S ₁ = 0.3S ₂ ).

The sealing device of the present invention constructed as described above
In the case of a rolling bearing incorporating this, install it on the seal material 7a.
With respect to a virtual plane including the central axis of the intermediate seal lip 15b.
The area S of the portion near the base end in the cross section₁ The part near the tip
Area S₂ 0.5 times or less (S₁ ≤ 0.5S
₂ ). Therefore, the basic part of the intermediate seal lip 15b is
Can be easily elastically deformed. When using, the inner ring 11
By tilting or eccentric with respect to the outer ring 8, the core metal 5
And the distance between the outer peripheral surface of the inner diameter side cylindrical portion 12 and
Even if (some approached or moved away), the above
The leading edge of the intermediate seal lip 15b constitutes the slinger 6.
Follow the movement of the outer peripheral surface of the inner diameter side cylindrical portion 12
Obey. Therefore, the tension of the intermediate seal lip 15b is increased.
The change in can be suppressed. Therefore, this intermediate seal
Suppresses the wear of the tip edge of the cap 15b and provides good sealing performance.
Can be obtained and the rotational torque of the rolling bearing 1 can be increased.
The size can be suppressed. Further, in the case of the present invention, the above intermediate
Area S of the portion near the base end of the seal lip 15b₁ The tip
Area S of the side portion₂ 0.1 times or more (S₁ ≧ 0.1S
₂ ). Therefore, this intermediate seal lip 15b
Make sure that the basic part of the
The durability of the rulip 15b can be secured. Conversely, this middle
The portion near the tip of the seal lip 15b does not become excessive.
Therefore, this intermediate seal lip 15b and this intermediate seal lip
Each of the outer and inner seal lips 14 adjacent to the cap 15b
It is possible to prevent the interference between a and 16.

Moreover, in the case of the present invention, the thickness of the intermediate portion of the intermediate seal lip 15b is made smaller than the thickness d _{1 of the} base end portion, and the thickness d ₁ of the base end portion is The thickness d ₂ of the minimum thickness portion of the intermediate portion is 0.80d ₁ ≦
It is regulated to satisfy d ₂ ≦ 0.98d ₁ . Therefore, in a state where the tip edge of the intermediate seal lip 15b is slidably contacted with the outer peripheral surface of the inner diameter side cylindrical portion 12, the portion from the base end portion to the intermediate portion of the intermediate seal lip 15b is substantially uniform. By elastically deforming, the stress applied to this part can be made almost equal. Therefore, unlike the case of the second example of the conventional structure shown in FIG. 10 described above, excessive stress does not occur in a part of the intermediate seal lip 15b, and fatigue due to stress (reduction of elasticity) is caused. Can be less likely to occur, and the sealing performance of the rolling bearing 1 can be sufficiently secured for a long period of time.

Further, in the case of this example, the three seal lips 14a, 15 including the intermediate seal lip 15b are included.
All of b and 16 are inclined in a direction toward the axially outer side of the rolling bearing 1 toward the respective leading edges. For this reason, the grease filled in the rolling bearing 1 is not allowed to adhere to the leading edges of the seal lips 14a, 15a, 16 and the slinger 6.
It is appropriately supplied to the sliding contact part with. Therefore, the lubrication state of each of these sliding contact portions should be kept good, the rotational torque of the rolling bearing 1 should be kept low, and each sliding contact portion should be covered with grease to improve the sealing performance of each sliding contact portion. You can Furthermore, all the sealing lips 14a, 15b, 16
Since the base ends of the seal lips can be separated from each other, the movements of the adjacent seal lips 14a, 15b, 16 do not interfere with each other. Therefore, the tip edges of the respective seal lips 14, 15a, 16a can better follow the movement of the surface of the slinger 6 to obtain a better sealing performance, and the rotational torque of the rolling bearing 1 can be improved. It is possible to further suppress the increase of.

Next, the result of the first simulation conducted by the inventor of the present invention to confirm the effect of the present invention will be described. In this first simulation, the conventional product having the structure shown in FIG. 3 and the product of the present invention having the structure of the present invention shown in FIGS. 1 and 2 were used to measure the respective parts of the intermediate seal lips 15a and 15b. The influence of the thickness relationship on the magnitude of strain of the intermediate seal lips 15a and 15b was examined.

The conventional product having the structure shown in FIG.
It has the same structure as the second example of the conventional structure shown in FIG.
The thickness of the intermediate seal lip 15a is
From the tip to the middle part
It is rapidly increasing. Also, this intermediate seal lip 1
The thickness of the base end of 5a is d₁ And the thickness suddenly increases in the middle part
The thickness of the changing part is d₂ And then d₂ = 1.3
d₁ I am trying. Also, in the intermediate seal lip 15a
It is a cross section about an imaginary plane including the axis and has a thickness d. ₁ Is
From the base end to the intermediate portion of the intermediate seal lip 15a
The thickness changes rapidly, the thickness d₂ Over the part that is
Area S of the part₁ And the thickness changes abruptly in this middle part
Area S from the part to the tip edge₂ The relationship with₁ 
= 0.5S₂ I am trying.

On the other hand, the relationship between the thickness d ₁ of the base end portion of the present invention used in this simulation and the thickness d ₂ of the minimum thickness portion of the intermediate portion is d ₂ = 0.90d ₁ I am trying. Further, in the axial cross section of the intermediate seal lip 15b of the present invention, the area S ₁ of the portion extending from the base end portion to the minimum thickness portion and the area S _{2 of} the portion extending from the minimum thickness portion to the tip edge are shown. The relationship is S ₁ = 0.3S ₂ .

In the conventional product and the product of the present invention, with the tip edges of the intermediate seal lips 15a and 15b slidably contacting the outer peripheral surface of the inner diameter side cylindrical portion 12 of the slinger 6,
The strain distribution from the base end portions of the intermediate seal lips 15a and 15b to the intermediate portion was obtained by the finite element method. In the intermediate seal lips 15a and 15b shown in FIGS.
The strain distribution thus obtained is shown. The numbers with a minus sign shown in each of these figures represent the magnitude of the strain (compressive strain) generated in each part of the intermediate seal lips 15a and 15b.

As is clear from the results of the first simulation shown in each of these figures, in the case of the conventional product shown in FIG. 3, the maximum strain is generated at the outer end portion of the base end portion of the intermediate seal lip 15a. Is as large as -0.15. On the other hand, in the case of the product of the present invention shown in FIG. 2, the maximum strain is −0 in a relatively wide range from the portion near the outer diameter of the base end portion of the intermediate seal lip 15b to the portion near the outer diameter of the intermediate portion. .12
It is 20% smaller than the conventional product. Therefore,
In the case of the product of the present invention, the maximum stress generated in the intermediate seal lip 15b can be reduced, and the fatigue-induced fatigue can be suppressed.

Next, FIG. 4 shows the result of the second simulation conducted by the inventor of the present invention to confirm the effect of the present invention. In this second simulation,
The relationship between the thickness ratio d ₂ / d ₁ between the base end portion and the intermediate portion of the intermediate seal lip 15b and the absolute value of the maximum strain generated in the intermediate seal lip 15b was determined. As is apparent from the result of the second simulation shown in FIG. 4, the ratio d ₂
When / d ₁ is 0.80 or more and 0.98 or less (the range shown by the arrow a in FIG. 4), which is the range of the present invention, the maximum strain of the intermediate seal lip 15b can be suppressed to a small value,
The maximum stress generated in the intermediate seal lip 15b can be reduced.

Next, FIG. 5 shows the inventor of the present invention.
Of the third simulation, which was conducted to confirm the effect.
The results are shown. In this third simulation,
It has a structure similar to the first example of the conventional structure shown in FIG.
By using the conventional product and the product of the present invention, an intermediate seal lip
In a cross section about an imaginary plane including the central axes of 15 and 15b,
Area S of the part near the base end₁ And area S near the tip₂ With
Ratio S₁ / S₂ Is the difference between the contact between the seal lip and the slinger.
Circumferential position of the contact portion and the intermediate seal lips 15 and 1
The effect of 5b on the relationship with the tension was examined. Conventional
Area S for goods₁ , S₂ The border of the middle seal lip
It was set as the minimum thickness part in which the thickness becomes the minimum in the middle part of 15.
The ratio of the conventional product used in this simulation
S₁ / S ₂ Is 1.0, and the ratio S for the product of the present invention is₁ / S
₂ Was 0.3.

Regarding the above-mentioned conventional product and the product of the present invention, in a state in which the slinger 6 is inclined with respect to the core metal 5 by a predetermined angle, the distribution of the tightening force of the intermediate seal lips 15, 15b in the circumferential direction. Was obtained by the finite element method. In FIG. 5, the horizontal axis represents the circumferential position of the sliding contact portion between the tip edges of the intermediate seal lips 15 and 15b and the outer peripheral surface of the slinger 6, and the vertical axis represents the tightness of the intermediate seal lips 15 and 15b. Power
Each represents. The numerical value on the vertical axis is a relative value when the average value of the tightening force of the intermediate seal lip 15 is set to 1 when the slinger 6 is not tilted with respect to the core metal 5 and the average value is used as a reference. ing. Further, in the figure, the solid line represents the product of the present invention, and the broken line represents the product of the prior art. The tightening force of the intermediate seal lips 15 and 15b is shown when the slinger 6 is inclined with respect to the core metal 5 by a predetermined angle. There is. The alternate long and short dash line represents the straining force when the slinger 6 is not tilted with respect to the cored bar 5.

As is clear from the results of the simulation shown in FIG. 5, when the slinger 6 is inclined with respect to the core metal 5 in the conventional product, the tension force in the circumferential direction of the sliding contact portion is about 0. The range was from 0.7 to about 1.5. On the other hand, in the case of the product of the present invention, the straining force changed in a relatively narrow range of about 0.8 to about 1.2. As is clear from the results of such a simulation, the intermediate seal lip 1
In the cross section of 5b in the axial direction, the area S _{1 of the} portion near the base end
Is set to 0.3 times the area S ₂ of the portion near the tip. In the case of the product of the present invention, the maximum value and the minimum value of the tightening force of the intermediate seal lip 15b are obtained even when the slinger 6 is inclined with respect to the core metal 5. The difference from the value can be reduced. From this, it is understood that the followability of the intermediate seal lip 15b with respect to the movement of the outer peripheral surface of the slinger 6 can be improved.

Next, in FIG. 6, the intermediate seal lip 15b is shown with the slinger 6 tilted with respect to the core metal 5 by a predetermined angle.
The ratio S ₁ / S ₂ of the area S _{1 of the} portion near the base end to the area S _{2 of the} portion near the tip in a cross section about an imaginary plane including the central axis of
And the amplitude of the tension force of the intermediate seal lip 15b. As is apparent from FIG. 6, when the ratio S ₁ / S ₂ is 0.5 or less (S ₁ / S ₂ ≤
At 0.5), the amplitude of the tensioning force can be suppressed to be small. On the other hand, when the ratio S ₁ / S ₂ exceeds 0.5 (S ₁ / S ₂ > 0.5), as the ratio S ₁ / S ₂ increases, The amplitude increases sharply.
When the amplitude of the straining force increases in this way, the slinger 6
The followability of the intermediate seal lip 15b with respect to the movement of the outer peripheral surface becomes poor.

On the other hand, in order to set the ratio S ₁ / S ₂ to less than 0.1, the area S ₁ of the portion near the base end of the intermediate seal lip 15b should be made sufficiently small, or the area S of the portion near the tip should be S. ₂ must be large enough. When the area S ₁ of the portion of the intermediate seal lip 15b near the base end is made sufficiently small, the thickness of the portion of the intermediate seal lip 15b near the base end becomes too small, so that sufficient durability is secured. become unable. Further, when the area S ₂ of the portion near the tip of the intermediate seal lip 15b is made sufficiently large, the outer seal lip 14a (or the inner seal) provided in a part of the seal material 7a adjacent to the intermediate seal lip 15b. The lip 16) (see FIGS. 1 and 2) and the intermediate seal lip 15b easily interfere with each other. In the case of the present invention, as described above, the ratio S ₁ / S ₂ is 0.1S ₂ ≤S ₁ ≤0.
Since the regulation is performed so as to satisfy 5S ₂ , it is possible to improve the followability of the intermediate seal lip 15b with respect to the movement of the slinger 6 while preventing the inconvenience described above from occurring.

The sealing device of the present invention and the rolling bearing incorporating the same can be used regardless of whether the inner ring 11 or the outer ring 8 constituting the rolling bearing 1 rotates during use.
Further, in the sealing device of the present invention and the rolling bearing incorporating the sealing device, the inner ring 11 is externally fitted and fixed to the outer peripheral surface of the hub for supporting the wheel, and the outer ring 8 of the knuckle constituting the suspension system of the automobile. It can also be used by incorporating it into a hub unit that can be internally fitted and fixed in the support hole. Further, in this case, a fixed side flange for fixing to the end surface of the knuckle can be formed on the outer peripheral surface of the outer ring 8. Furthermore,
As shown in FIG. 7, the inner ring 11 having an inner ring raceway 18 on the outer peripheral surface is externally fitted and fixed to the outer peripheral surface of the inner end portion of the hub 21, and
It is also possible to incorporate the sealing device 17b of the present invention into a hub unit in which another inner ring raceway 18 is formed on a portion of the outer peripheral surface of the intermediate portion of the hub 21 which is separated from the inner ring 11. Further, in the case of the hub unit shown in FIG. 7, a fixed side flange 23 for fixing to the end surface of the knuckle 22 is formed on the outer peripheral surface of the outer ring 8. Further, a rotary side flange 24 for fixing the wheel is formed on the outer peripheral surface of the hub 21 near the outer end thereof. The hub unit shown in FIG.
Like the sealing device 17c incorporated between the outer peripheral surface of the intermediate portion of 1 and the inner peripheral surface of the outer end portion of the outer ring 8, the tip edge of the seal lip provided on the seal material 7a is connected to the outer periphery of the hub 21 (or the inner ring 11). The present invention can also be applied to a structure in which the surface is brought into direct sliding contact. Furthermore, a hub is provided on the outer ring side (outer ring rotation type).
It can also be implemented in a hub unit.

[0037]

Since the present invention is constructed and operates as described above, it is possible to realize a sealing device having excellent sealing property and durability and a small rotating torque. Therefore, it is possible to prevent various foreign substances such as rainwater, mud, and dust from entering the internal space of the rolling bearing and the hub unit, improve the durability of the rolling bearing and the hub unit, and improve fuel efficiency and acceleration performance. The driving performance of the vehicle, which is the center of the vehicle, can be improved.

[Brief description of drawings]

FIG. 1 is a view similar to FIG. 10, showing a first example of an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing a state in which a sealing material, a cored bar, and a slinger are combined from the state of FIG.

FIG. 3 is a view similar to FIG. 2, showing an example of a conventional structure used for comparison.

FIG. 4 is a thickness ratio d ₂ / d ₁ of each part of the intermediate seal lip.
And the maximum strain (absolute value) that occurs in this intermediate seal lip
FIG.

FIG. 5 is a diagram showing a distribution of the tension force of the intermediate seal lip in the circumferential direction.

FIG. 6 is a diagram showing a relationship between a ratio S ₁ / S ₂ of cross-sectional areas of a portion near the base end and a portion near the tip of the intermediate seal lip and the amplitude of the tension force of the intermediate seal lip.

FIG. 7 is a cross-sectional view showing a hub unit incorporating the sealing device of the present invention.

FIG. 8 is a half sectional view showing the first example of the conventional structure in which the sealing device is incorporated in a rolling bearing.

FIG. 9 is a partially enlarged sectional view showing only the sealing device.

FIG. 10 is a partial cross-sectional view showing the sealing device of the second example of the conventional structure in a state before the core metal and the seal material are combined with the slinger.

[Explanation of symbols]

1 Rolling bearing 5 core metal 6 slinger 7,7a Seal material 8 outer ring 9 Outer diameter side cylindrical part 10 Inner ring part 11 inner ring 12 Inner diameter side cylindrical part 13 Outer ring part 14, 14a Outer seal lip 15, 15a, 15b Intermediate seal lip 16 Inner seal lip 17, 17a to 17c Sealing device 18 Inner ring track 19 Outer ring track 20 rolling elements 21 Hub 22 knuckles 23 Fixed side flange 24 Rotating side flange 25 corner R part

Claims (3)

[Claims] 1. A rolling bearing in which a plurality of rolling elements are provided between an inner ring raceway provided on an outer peripheral surface of an inner ring and an outer ring raceway provided on an inner peripheral surface of an outer ring so that the inner ring and the outer ring can freely rotate relative to each other. And a holding member fixed to one of the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring to close the space between the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring, and an elastic material. And a sealing material part of which is coupled and fixed to the holding member, and a part of the sealing material is provided with a tip edge thereof.
A radial surface provided on the other of the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring, or a radial direction in sliding contact with the radial surface of a member supported by the other. In a sealing device provided with a seal lip, the thickness of the radial seal lip becomes smaller from the base end portion toward the middle portion, and the thickness from the middle portion to the tip edge is It is thicker than the middle part,
Moreover, the thickness of the radial seal lip is maximized in a part of the portion extending from the intermediate portion to the tip edge, and the thickness of the proximal end portion of the radial seal lip is d ₁ , the intermediate portion. Let d _{2 be} the thickness of the minimum thickness part where the thickness is the minimum in the part, and in the cross section about the imaginary plane including the central axis of this radial seal lip, of the part extending from the base end part to the minimum thickness part. If the area is S ₁ and the area from the minimum thickness portion to the tip edge is S ₂ , 0.80 d ₁ ≤d
₂ ≤ 0.98d ₁ and 0.1S ₂ ≤ S ₁ ≤ 0.5
Sealing device characterized by satisfying S ₂ . 2. A rolling bearing incorporating at least one sealing device according to claim 1. 3. A hub unit in which at least one sealing device according to claim 1 is incorporated, wherein the inner ring or the outer ring is a hub for fixing the wheel.