JP2001215133A - Bearing for wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent invasion of water in the fitting part of seal plates, improve the life of bearing, resolve the problem of removal and move of the seal plates and facilitate gain of magnetic flux density. SOLUTION: A seal device 5 is provided between an inner member 1 and an outer member 2. The seal device 5 has an elastic member 14 to be an encoder grid on the first seal plate 11. To the second seal plate 12, a sideslip 16a and radial lips 16b and 16c are provided in combination. At least on the first seal plate 11 among the first and the second seal plates 11 and 12, a metal layer 20 with lower Young's modulus than the inner member 1 is formed on the surface of a magentic body, a steel plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing for a wheel in an automobile or the like, and more particularly, to a sealing structure in which an encoder lattice for detecting rotation is integrated.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 5, in a wheel bearing in which a sealing device 105 is provided between an inner member 101 and an outer member 102 which are in rolling contact with each other via a rolling element 103, an encoder grating 106 is provided on the sealing device 105. (For example, Japanese Patent Application Laid-Open No. 6-281018).
issue). The sealing device 105 fits the first and second seal plates 107 and 108, each having an L-shaped cross section, with the inner member 101 and the outer member 102, respectively, and attaches the lip 109 to the second seal plate 107. It is provided. The first seal plate 107 is called a slinger. The encoder grating 106 is an elastic member mixed with magnetic powder,
Is vulcanized and adhered to the seal plate 107 of FIG. The encoder grating 106 is formed by alternately forming magnetic poles in the circumferential direction, and is detected by the magnetic sensor 110 disposed in a face-to-face manner.

[0003]

The seal plate 107 serving as a slinger and the inner member 101 serving as a rotating wheel are fitted in a press-fitted state. Have minute irregularities. Therefore, a small amount of water may enter the inside of the bearing from the fitting portion 111.
When such intrusion of water occurs, the sealing plates 107, 10
8, rust is generated, the internal grease is deteriorated, and the bearing life is shortened. Therefore, the inner member 10 of the seal plate 107
It is considered that a rubber layer is provided in the fitting portion 111 with the first member. However, if a thick rubber layer is interposed, the fitting force becomes insufficient, and there is a possibility that the seal plate 107 may come off or move into the bearing. In the case where the packing is interposed in the fitting portion 111, the problem of detachment or movement occurs. Instead of interposing an elastic member, it is possible to improve the adhesion by making the material of the seal plate 107 itself soft, but since such a material is a non-magnetic material, the encoder grid 106
The function of the magnetic core cannot be obtained, and the magnetic flux density is insufficient.

[0004] Regarding the rust prevention of the seal plate 107, a magnetic stainless steel (SUS430MA, SUS430 with niobium or Ni) having corrosion resistance equivalent to SUS304 is used instead of a generally used magnetic material such as SUS430 having poor corrosion resistance.
SUS430MA can be obtained in the same manner as SUS430 in terms of magnetic flux density. However, the material is expensive, and even if such a material is used, intrusion of water cannot be prevented, and reduction in bearing life due to deterioration of grease cannot be prevented.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent water from entering a fitting portion of a seal plate, thereby improving the life of the bearing, preventing the seal plate from coming off or moving, and ensuring the magnetic flux density. It is to provide an easy wheel bearing.

[0006]

SUMMARY OF THE INVENTION A wheel bearing according to the present invention comprises an inner member and an outer member, a plurality of rolling elements housed between the inner and outer members, and an annular end portion between the inner and outer members. In a wheel bearing comprising a seal device for sealing a space, the seal device has first and second annular seal plates respectively attached to different ones of the inner member and the outer member. The two seal plates are formed in an L-shaped cross section including a cylindrical portion and an upright plate portion, and face each other. The first seal plate is a member on the rotating side of the inner member and the outer member. The upright portion is disposed on the outer side of the bearing, and an elastic member containing magnetic powder mixed therein is vulcanized and bonded to the upright portion. Is formed, and the second sealing plate is formed of a side lip and a cylinder which are in sliding contact with the standing plate portion. A radial lip slidingly contacting the first and second seal plates. The cylindrical portion of the second seal plate and the tip of the upright plate portion of the first seal plate face each other with a slight radial gap. Of the two seal plates, at least the first seal plate is characterized in that a metal layer having a lower Young's modulus than the rotating member is formed on the surface of a steel plate made of a magnetic material. According to this configuration, the first
An elastic member mixed with magnetic powder is vulcanized and bonded to the standing plate portion of the seal plate, and magnetic poles are alternately formed in the circumferential direction. Thus, a so-called encoder lattice is formed by this elastic member. The rotation can be detected by the facing magnetic sensor. As for the seal between the inner and outer members, the sliding contact of each seal lip provided on the second seal plate and the tip of the upright plate portion of the first seal plate on the cylindrical portion of the second seal plate have a slight radial direction. It is obtained with a labyrinth seal constituted by facing each other with a gap. At the fitting portion between the first seal plate and the member on the rotating side, minute irregularities are formed for surface roughness and shape accuracy, but a metal layer having a lower Young's modulus than the member on the rotating side seals. Since it is formed on the surface of the plate, the recesses of the unevenness are filled with the soft metal of the metal layer, and the sealing property is improved. Therefore, it is possible to prevent the grease from being deteriorated due to water entering the bearing, and the bearing life is improved.
Since a steel plate is used for the first seal plate, the magnetic flux density of the encoder lattice can be increased. Since the metal layer on the surface of the steel sheet is thin, even a non-magnetic material has little effect on the magnetic flux density.

In the present invention, the metal layer may be a plating layer. If it is a plating layer, a metal layer can be easily formed. In each of the above structures of the present invention, the metal having a low Young's modulus may be one metal selected from zinc, tin, gold, silver, and copper.

In each of the above-described configurations of the present invention, the thickness of the metal layer may be 5 to 30 μm. The surface roughness of the fitting surface of the member fitted with the first seal plate is Rmax 3.0.
(Or Ra 0.63), the thickness of the metal layer needs to be at least 5 μm or more in order to fill the unevenness due to the surface roughness. On the other hand, even if the thickness is set to 30 μm or more, the effect is not changed to the same extent. Conversely, the flatness is lost, and a great amount of time is required for forming the metal layer, resulting in an increase in cost. Therefore, the thickness of the metal layer is preferably in the above range. Making the thickness of the metal layer 5 to 30 μm in this way is particularly effective when the metal layer is a plating layer.

In each of the above configurations of the present invention, the surface roughness of the fitting surface of the first seal plate may be Rmax 3.0 or less, preferably Rmax 0.5 to 2.2. Conventionally, such a sealing plate is larger than Rmax 3.0 and not more than 7.5, but by increasing the accuracy of the surface roughness in this way, the unevenness due to the surface roughness is filled with a metal layer. Will be effective.

In each of the above configurations of the present invention, a fitting surface of the rotating side member with the seal plate may be formed on a plunge-cut ground surface. According to the plunge cut, the raceway surface of the rolling element of the rotating side member and the fitting surface can be formed by simultaneous grinding, and misalignment of the two can be prevented. In other words, when grinding is performed separately, not only is the misalignment between the fitting surface serving as the sealing surface and the raceway surface generated, but also if the fitting surface is formed by sensorless grinding or the like, the ground surface becomes spiral, There is a concern about intrusion of dust and the like. Plunge cutting is grinding in which a grinding wheel is cut at a right angle to a workpiece, so that the above problem can be solved. in this way,
When the fitting surface of the rotating side member with the seal plate is a plunge-cut ground surface, the fitting surface is Rma
It is desirable that the surface is finished to a surface roughness of x3.0 or less. This fitting surface is also preferably in the range of Rmax 0.5 to 2.2. By increasing the accuracy of the surface roughness of the fitting surface, the effect of filling the unevenness due to the surface roughness with the metal layer becomes effective.

[0011]

Embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the wheel bearing includes an inner member 1 and an outer member 2, a plurality of rolling elements 3 housed between the inner and outer members 1 and 2, and an inner member 1 and an outer member 2. And a sealing device 5 for sealing the annular space at the end. The inner member 1 and the outer member 2 are connected to the raceway surfaces 1a, 2 of the rolling element 3.
a, and each track surface 1a, 2a is formed in a groove shape. The inner member 1 and the outer member 2 each include a rolling element 3
Inner and outer members that are rotatable with respect to each other through the bearing. Even if the bearing inner ring and the bearing outer ring are used alone, the bearing inner ring and the bearing outer ring are combined with another component. It may be an assembled member. Further, the inner member 1 may be a shaft. The rolling element 3 is formed of a ball or a roller. In this example, a ball is used.

FIG. 3 shows an example of the overall configuration of the wheel bearing. The wheel bearing is a double row rolling bearing, more specifically, a double row angular contact ball bearing. The bearing inner ring has a hub wheel 6 and a separate body fitted to the end outer diameter of the hub wheel 6. It is composed of the inner ring 1A. A raceway surface of each rolling element row is formed on the hub wheel 6 and the separate inner ring 1A. The separate inner ring 1A serves as the inner member 1 in the example of FIG. One end (for example, an outer ring) of a constant velocity universal joint 7 is connected to the hub wheel 6, and a wheel (not shown) is attached to a hub portion 6 a of the hub wheel 6 with a bolt 8. The other end (for example, the inner ring) of the constant velocity universal joint 7 is connected to the drive shaft. The outer member 2 is
It is composed of a bearing outer ring having a flange 2b and is attached to a housing 10 composed of a knuckle or the like. The outer member 2 is
It has a raceway surface of both rolling element rows. The rolling elements 3 are held by a holder 4 for each row. One end of the annular space between the inner member 1 and the outer member 2, that is, the end on the center side of the axle, is sealed by the sealing device 5. The end of the annular space between the outer member 2 and the hub wheel 6 is sealed with another sealing device 13.

As shown in FIGS. 1 and 2, the seal device 5 has first and second annular seal plates 11 and 12 attached to the inner member 1 and the outer member 2, respectively. These seal plates 11 and 12 are attached to the inner member 1 and the outer member 2 by being fitted in a press-fit state. The two seal plates 11 and 12 are formed in an L-shaped cross section including the cylindrical portions 11a and 12a and the upright plates 11b and 12b, and face each other. The first seal plate 11 is fitted to the inner member 1, which is a member on the rotation side, of the inner member 1 and the outer member 2, and serves as a slinger. The upright portion 11b of the first seal plate 1 is disposed on the outer side of the bearing, and an elastic member 14 mixed with magnetic powder is vulcanized and bonded. This elastic member 14
Is an encoder lattice, and magnetic poles N and S (FIG. 2) are formed alternately in the circumferential direction, and is a so-called rubber magnet. The magnetic poles N and S are formed to have a predetermined pitch p in the pitch circle PCD. By arranging the magnetic sensor 15 as shown in FIG. 1 so as to face the elastic member 14 serving as the encoder lattice, a rotary encoder for detecting the wheel rotation speed is configured.

The second seal plate 12 is a first seal plate 1
One side lip 16a slidingly contacting the upright plate portion 11b and radial lips 16b and 16c slidingly contacting the cylindrical portion 11a are integrally provided. These lips 16a to 16c are provided as a part of the elastic member 16 which is vulcanized and bonded to the second seal plate 12. Although the number of these lips 16a to 16c may be arbitrary, in the example of FIG.
6a and two radial lips 16c and 16b located inward and outward in the axial direction. The outer radial lip 16b may be replaced with, for example, a side lip as shown in FIG. 4, or may be omitted.

The cylindrical portion 12a of the second seal plate 12 and the first
Of the sealing plate 11 with a slight radial gap, and the labyrinth seal 1
7.

At least the first seal plate 11 of the first seal plate 11 and the second seal plate 12 is provided on the surface of a steel plate made of a magnetic material by a metal layer 20 having a Young's modulus lower than that of the inner member 1. Is formed. In the example of FIG. 1, a metal layer 20 is formed on both the first and second members 1 and 2. The metal layer 20 is, for example, a plating layer. The inner member 1 is made of, for example, a steel material such as bearing steel. As the metal having a low Young's modulus, one metal selected from zinc, tin, gold, silver, and copper is used. The thickness of the metal layer 20 is 5 to 30 μm.
m. In particular, when the metal layer 20 is a plating layer, this thickness range is preferable.

Since the first seal plate 11 has the metal layer 20 formed thereon, a magnetic material having high mechanical strength, for example, a rolled steel plate (a cold rolled steel plate such as SPCC) or the like can be used without using expensive stainless steel. , SK5 and the like, and carbon steel plates such as S45C and the like. Even if such a steel plate is used, the metal layer 20 having rust resistance is formed on the surface thereof, so that high rust resistance can be obtained. Use of such an inexpensive steel plate is advantageous in terms of cost. When the metal layer 20 is formed, the second seal plate 12 also has a high rust prevention property, so that there is no need to select a material that is unlikely to generate rust.
Inexpensive materials can be selected. However, the second seal plate 12
Is preferably a non-magnetic metal plate.

A fitting surface 1b of the inner member 1 with the seal plate 11
Are ground at the same time as the raceway surface 1a and are plunge cut. The surface roughness of this fitting surface 1b is finished to Rmax 3.0 or less or Ra 0.63 or less.
ax is preferably in the range of 0.5 to 2.2. First
The surface roughness of the steel plate on the fitting surface 11aa of the seal plate 11 with the inner member 1 is also not more than Rmax 3.0 or Ra.
0.63 or less, and Rmax is preferably in the range of 0.5 to 2.2.

According to the wheel bearing of this configuration, the elastic member 14 mixed with the magnetic powder is vulcanized and bonded to the upright portion 11b of the first seal plate 11, and the magnetic poles N and S are alternately arranged in the circumferential direction.
Is formed, the elastic member 14 forms a so-called encoder lattice, and the magnetic sensor 1 facing the encoder lattice is formed.
5, the rotation can be detected. Regarding the seal between the inner and outer members 1 and 2, the first seal plate 11 is attached to the cylindrical portion 12 a of the second seal plate 12 by sliding contact of the seal lips 16 a to 16 c provided on the second seal plate 12. Standing plate part 1
The labyrinth seal 17 is formed by the front ends of the labyrinth seals 1b facing each other with a slight radial gap.

In the fitting portion between the first seal plate 11 and the inner member 1, minute irregularities are formed for the surface roughness and shape accuracy of the fitting surface 1b of the inner member 1, and Seal plate 1
Fine irregularities are also formed on the steel plate portion of the first fitting surface 11aa. However, since the metal layer 20 having a lower Young's modulus than the inner member 1 is formed on the surface of the seal plate 11,
The concave portion of the unevenness is filled with the soft metal of the metal layer 20, and the sealing performance is improved. Therefore, it is possible to prevent the grease from being deteriorated due to water entering the bearing, and the bearing life is improved. Since the first seal plate 11 is made of a steel plate, the magnetic flux density of the encoder lattice can be increased. Since the metal layer on the surface of the steel sheet is thin, the influence on the magnetic flux density is small. Further, the metal layer 2 is provided on the first seal plate 11.
Since 0 is provided, the first seal plate 11 can provide rust prevention even if the above various steel plates such as a rolled steel plate which is a magnetic material having high mechanical strength are used. Therefore, it is not necessary to use expensive stainless steel or the like, which is advantageous in cost.

The thickness of the metal layer 20 is set to 5 to 30 as described above.
In the case of μm, unevenness due to the surface roughness of the mating surface can be sufficiently filled, and the flatness of the mating surface is secured,
Also, the cost can be reduced. That is, the surface roughness of the fitting surface 1b of the inner member 1 fitted with the first seal plate 11 is Rmax
When the thickness is about 3.0 (or Ra 0.63), the thickness of the metal layer needs to be at least 5 μm or more in order to fill the unevenness due to the surface roughness. On the other hand, this thickness is 30μ
Even if it is more than m, the effect is the same, and conversely, the flatness is lost, and the formation of the metal layer 20 requires a lot of time, so that the cost increases. Therefore, the thickness of the metal layer 20 is preferably in the above range.

When the surface roughness of the fitting surface 11aa of the first seal plate 11 is set to Rmax 3.0 or less, particularly, Rmax
In the case of x0.5 to 2.2, the effect of filling the unevenness due to the surface roughness with the metal layer 20 becomes more effective.

When the fitting surface 1b of the inner member 1 is formed as a ground surface by plunge cutting, the raceway surface 1a and the fitting surface 1b can be formed by simultaneous grinding, so that misalignment of the two can be prevented. In the case of the plunge cut, it is easy to reduce the surface roughness of the fitting surface 1b to Rmax 3.0 or less. By thus increasing the surface roughness accuracy, it is possible to further improve the sealing performance.

In the above embodiment, in the example of FIG.
Although one side lip 16a and two radial lips 16c and 16b positioned inward and outward in the axial direction are provided, the outer radial lip 16b is replaced with, for example, a side lip as shown in FIG. Or may be omitted.

[0025]

According to the wheel bearing of the present invention, at least the first seal plate of the first seal plate provided with the elastic member serving as the encoder grid and the second seal plate provided with the seal lip is provided. Since a metal layer having a lower Young's modulus than the rotating member is formed on the surface of the steel plate made of a magnetic material, water can be prevented from entering the fitting portion of the seal plate, and the bearing life can be improved. In addition, there is obtained an advantage that the problem of detachment or movement of the seal plate does not occur and that the magnetic flux density can be easily secured.

[Brief description of the drawings]

FIG. 1A is a partial sectional view of a wheel bearing according to an embodiment of the present invention, and FIG. 1B is an enlarged sectional view of a sealing device thereof.

FIG. 2 is a partial front view of an elastic member serving as the encoder lattice.

FIG. 3 is a sectional view of an overall example of the wheel bearing.

FIG. 4 is a sectional view of a modified example of the sealing device.

FIG. 5 is a sectional view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Inner member 2 ... Outer member 3 ... Roller element 5 ... Seal device 11 ... First seal plate 12 ... Second seal plate 11a, 12a ... Cylinder portion 11b, 12b ... Stand plate portion 14 ... Elastic member 16a １６16c: lip portion 20: metal layer N, S: magnetic pole

Continued on front page F term (reference) 2F077 AA41 NN04 NN08 NN26 PP05 VV03 VV09 VV11 VV13 VV33 VV35 3J006 AE23 AE40 3J016 AA02 BB03 CA04

Claims (7)

[Claims] 1. A wheel bearing comprising an inner member and an outer member, a plurality of rolling elements housed between the inner and outer members, and a seal device for sealing an end annular space between the inner and outer members. In the above, the sealing device has first and second annular seal plates respectively attached to different ones of the inner member and the outer member, and both seal plates are respectively formed with a cylindrical portion. A plate portion is formed in an L-shaped cross section and faces each other.
The seal plate is fitted to the rotating member of the inner member and the outer member, the upright portion is disposed on the outer side of the bearing, and the magnetic powder is mixed in the upright portion. The elastic member is vulcanized and bonded, and the elastic member is alternately formed with magnetic poles in the circumferential direction. The second seal plate integrally includes a side lip slidingly contacting the upright plate portion and a radial lip slidingly contacting the cylindrical portion. And a cylindrical portion of the second seal plate and a tip of an upright portion of the first seal plate are opposed to each other with a slight radial gap. The wheel bearing according to claim 1, wherein the seal plate is formed by forming a metal layer having a lower Young's modulus than the rotating member on the surface of a steel plate made of a magnetic material. 2. The wheel bearing according to claim 1, wherein the metal layer is a plating layer. 3. The metal having a low Young's modulus is zinc, tin,
The wheel bearing according to claim 1 or 2, wherein the bearing is one metal selected from gold, silver, and copper. 4. The wheel bearing according to claim 1, wherein the thickness of the metal layer is 5 to 30 μm. 5. The wheel bearing according to claim 1, wherein the fitting portion of the first seal plate has a surface roughness of Rmax 3.0 or less. 6. The wheel bearing according to claim 1, wherein a fitting surface of the rotating side member with the seal plate is formed as a plunge-cut ground surface. 7. The wheel bearing according to claim 6, wherein a fitting surface of the rotating side member with the seal plate is finished to a surface roughness of Rmax 3.0 or less.