JP2002147478A - Wheel bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain a rotation detection accuracy caused by a detection of an encoder lattice by enhancing an anti-corrosion property at an engagement part of a member at a rotation side and a seal plate and preventing a deflection deformation of the seal plate caused by a rust. SOLUTION: This wheel bearing comprises an inner member 1 and an outer member 2; a plurality of rolling elements 3 stored between these inner and outer members; and a seal device 5 for sealing an annular space at an end between the inner and outer members 1, 2. The seal device 5 has a first and second annular seal plates 11, 12. Both seal plates 11, 12 comprise cylindrical parts 11a, 12a and standing plate parts 11b, 12b, are formed to an L shape of cross section and are opposed to each other. The first seal plate 11 is engaged with the member at a rotation side of the inner member 1 and the outer member 2 and an elastic member 14 to which a magnetic substance powder is mixed is vulcanized and adhered to the standing plate part. An anti- corrosion processing layer 21 is formed on an engagement surface of the member at a rotation side with which the first plate 11 is engaged.

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 bearing for a wheel in which an encoder lattice for detecting rotation is integrated.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, in a wheel bearing in which a sealing device 105 is provided between an inner member 101 and an outer member 102 which come into contact with each other via a rolling element 103, an encoder grid 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 108. 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-fit state, but rust is generated in the fitted portion due to an external environment. Sometimes. Wheel bearings are in a harsh environment that receives muddy water and the like due to road surface conditions and the like. In particular, when used in an environment where muddy salt water or the like is used, rust easily occurs. Thus, rust is generated at the fitting portion. When this rust further progresses, the volume expands and swells, and the sealing plate 10
The bonded portion of the encoder grid 106 in FIG. Therefore, there is a possibility that the detection by the magnetic sensor 110 will be confused, and adverse effects such as a decrease in rotation detection accuracy will be caused.

An object of the present invention is to improve rust prevention at a fitting portion between a rotating member and a seal plate, prevent bending and deformation of the seal plate due to rust, and improve rotation detection accuracy by detecting an encoder grid. An object of the present invention is to provide a wheel bearing that can be maintained.

[0005]

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 circumferential portion and an upright plate portion, and are opposed to each other. The first seal plate is provided on the rotation side of the inner member and the outer member. The upright portion is arranged on the outer side of the bearing, and the upright portion is vulcanized and bonded to an elastic member mixed with magnetic powder. A magnetic pole is formed, and the second seal 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 cylindrical member of the second seal plate and a tip of the upright plate portion of the first seal plate with a slight radial gap therebetween; Wherein a rustproofing layer is formed on a fitting surface on which the first seal plate is fitted.
According to this configuration, the elastic member mixed with the magnetic powder is vulcanized and bonded to the upright portion of the first seal plate, and the magnetic poles are alternately formed in the circumferential direction. A grating is formed, and rotation can be detected by a magnetic sensor facing the grating. 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. Since the rust prevention treatment layer is formed on the fitting surface of the rotating member to which the first seal plate is fitted, rust prevention performance is improved. Therefore, bending deformation of the seal plate due to rust is prevented, and deformation of the encoder lattice provided on the seal plate is prevented. Therefore, even when used in a severe external environment, the rotation detection accuracy by detecting the encoder grid of the seal plate is maintained.

In the present invention, a rust preventive layer may be formed also on an exposed portion of the rotating side member where the first seal plate is fitted. The above-mentioned exposed portion is a portion that is exposed without contacting a shaft or a housing in a state where the bearing is incorporated in a vehicle body. For example, a width surface of a rotating-side member, a chamfered portion subsequent to the width surface, or the like. That is. Further, the above-mentioned fitting surface is a surface on which at least the first seal plate of the rotating member is actually fitted, but the first seal plate of the rotating member is fitted. It is preferable that a portion of the outer diameter surface or the inner diameter surface where the first seal plate is not actually fitted also forms the rust-proofing layer. With this configuration, not only the fitting portion of the first seal plate on the rotating side member but also the rust prevention property of the exposed portion in the vicinity is improved, and the deformation of the seal plate due to rust can be more reliably prevented. Can be prevented. As the rust preventive layer, various types such as plating and resin coating can be adopted, but a metal plated layer is preferable. As the metal plating layer, zinc plating, nickel plating, zinc-nickel plating, or the like is used. When the metal plating layer is used, it is possible to prevent the fitting force of the first seal plate from being reduced due to the elastic deformation of the rust prevention layer. If zinc or nickel plating is used, plating with high rust prevention can be performed at low cost.

[0007] In the present invention, the first seal plate may be formed of a magnetic material and a steel plate having rust prevention properties. By forming the first seal plate from a magnetic material and a steel plate having rust-preventing properties in this way, a sufficient magnetic flux density can be secured in the first seal plate serving as the magnetic core of the encoder lattice. The first seal plate is also prevented from being deformed due to the generation of rust on the first seal plate.

[0008]

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 end annular space. 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 part. 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 structure of a wheel bearing. The wheel bearing is a double row rolling bearing, more specifically, a double row angular contact ball bearing. The inner member 1 is formed of a bearing inner ring, and is of a split type in which a split inner ring is provided for each rolling element row. The outer member 2 comprises an integral bearing outer ring. The rolling elements 3 are held by the holders 4 for each row. One end of the annular space between the inner member 1 and the outer member 2 is sealed by the above-mentioned sealing device 5, and the other end thereof is formed by another sealing device 13.
Sealed.

As shown in FIG. 1, a sealing device 5 includes first and second members mounted on an inner member 1 and an outer member 2, respectively.
Annular seal plates 11 and 12. 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 respectively cylindrical portions 11a and 12a and upright plate portions 11
b and 12b are formed in an L-shaped cross section 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. Standing plate portion 11b of 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 to a side surface on the outer side. This elastic member 14 serves as an encoder lattice,
Magnetic poles N and S (FIG. 2) are formed alternately in the circumferential direction, which is a so-called rubber magnet. The magnetic poles N and S are formed so as to have a predetermined pitch p in a pitch circle diameter (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 elastic member 14 has a tip covering portion 14a that covers the tip inner surface from the tip portion of the standing plate portion 11b of the first seal plate 11.
have. The tip cover 14a may be omitted.

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. Second seal plate 12
In the figure, an elastic member 16 is held in a fitting portion with the outer member 2 which is a fixed member. That is, the elastic member 1
6 has a tip covering portion 16d that covers from the inner diameter surface of the cylindrical portion 12a to the outer diameter of the tip portion.
6 d is interposed in the fitting portion between the second seal plate 12 and the outer member 2. The tip portion 12aa of the cylindrical portion 12a of the second seal plate 12 is thinner than the other portion of the cylindrical portion 12a and is bent obliquely toward the inside diameter.
The top cover 16d covers aa. Note that the distal end covering portion 16d may be separated from other portions of the elastic member 16.

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. When the end covers 14a, 16d are provided on the elastic members 14, 16 of the first and second seal plates 11, 12, the gap between these end covers 14a, 16d is equal to the gap that constitutes the labyrinth seal 17. Become.

An example of the material of each member will be described. Inner member 1,
Both the outer member 2 and the rolling elements 3 are made of carbon steel such as bearing steel. The first seal plate 11 is a magnetic material and a material having rust prevention properties, and a magnetic steel plate such as a ferromagnetic material.
For example, a ferritic stainless steel sheet (JIS standard S
US430 series) or a rust-proofed rolled steel plate or the like. The second seal plate 12 is made of a steel plate, for example, a non-magnetic austenitic stainless steel plate (SUS30).
4 series) or a rust-proofed rolled steel plate.
For example, the first seal plate 11 may be a ferritic stainless steel plate, and the second seal plate 12 may be an austenitic stainless steel plate.

A rustproofing layer 21 is formed on the fitting surface of the inner member 1 which is the rotating member to which the first seal plate 11 is fitted, and on the other exposed portion of the inner member 1. ing. The exposed portion is a portion that is exposed without contacting a shaft or a housing in a state where the bearing is incorporated in a vehicle body. In this example, the exposed surface is a width surface of the inner member 1 and an inner diameter surface from the width surface. Part of chamfered part and track surface 1 on outer diameter surface
The portion from a to the width surface is a portion where the first seal plate 11 is not actually fitted. A rustproofing layer 21 is formed on the entirety of these exposed portions. Rust prevention treatment layer 21
For example, a metal plating layer or a resin layer such as a water-soluble acrylic resin-based coating film can be employed. When the metal plating layer is used, the formation of the rustproofing layer 21 is facilitated, and the fitting force of the first seal plate 11 is prevented from being reduced due to the elastic deformation of the rustproofing layer 21 or the like. When using a metal plating layer,
It is preferable to use a plating layer of zinc, nickel, or zinc-nickel. In addition, chrome plating or nickel-chrome plating may be used.

According to the wheel bearing of this configuration, the elastic member 14 containing 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.

The fitting surface 1b of the inner member 1, which is the rotating member to which the first seal plate 11 is fitted, has a rust-proof layer 21
Is formed, the rust prevention performance of the fitting portion is improved, and the deformation of the seal plate 11 due to rust can be prevented. Therefore, the elastic member 14 provided on the first seal plate 11
Is prevented from being deformed. Therefore, even when used in a severe environment, the rotation detection accuracy by detecting the encoder grid of the seal plate 11 is maintained. Further, since the rust preventive layer 21 is also formed on the exposed portion other than the fitting surface 1b of the inner member 1, not only the fitting portion of the first seal plate 11, but also the exposed portion near the fitting portion. The rust-preventing performance is also improved in the portions, and the bending deformation of the seal plate 11 due to rust is more reliably prevented.

In order to further improve the rust prevention performance, the first
As described above, the seal plate 11 is preferably formed of a magnetic material and a steel plate having rust prevention properties. By forming the first seal plate 11 from a magnetic material and a steel plate having rust-preventive properties, a sufficient magnetic flux density can be secured in the first seal plate 11 serving as the magnetic core of the encoder lattice, Due to the generation of rust on the first seal plate 11,
Compression occurs at the fitting portion with the inner member 1 so that the first seal plate 1
1 is also prevented from being deformed.

The rust-preventing performance of the wheel bearing of this embodiment and the conventional wheel bearing were compared by a composite salt spray test under the following conditions. In this test, 120 cycles were performed with the following processes 1 to 7 as one cycle, and 5, 15, 30, 6
The magnetic characteristics of the encoder lattice (elastic member 14) and the output characteristics of the rotary encoder are measured every 0, 90, and 120 cycles. 1. 1. Wet (50 ° C, 95% RH, 2 hours) Complex salt water (salt water + calcium chloride) spray (35 ° C., NaCl: 2.5%, CaCl ₂ : 2.5
% 2 hours) 3. Drying (60 ° C, 1 hour) 4. Wet (50 ° C, 95% RH, 6 hours) 5. Drying (60 ° C, 1 hour) 6. Wet (50 ° C, 95% RH, 6 hours) Drying (60 ° C., 1 hour) In this test, in the conventional wheel bearing, the rust covers the seal plate fitting portion of the rotating member at the time of 15 cycles, and the seal plate 11 is pressed by the rust, and the encoder is pressed. Deformation of the elastic member 14 serving as a lattice occurs, but in the wheel bearing of this embodiment, such rust is generated at the fitting portion of the first seal plate 11 at this point and also after 120 cycles. There was no decrease in magnetic and output characteristics. In addition,
In the conventional example as well, a problem of deformation of the seal plate 11 occurred, but at that time, the experiment was stopped, and the seal plate 11 was removed and observed. Although water was generated, no water entered the bearing.

As another experimental example, a test under the following conditions also confirmed that the bearing of this embodiment was superior to the conventional wheel bearing in terms of magnetic and output characteristics due to the generation of rust. . In this test, 120 cycles were performed with the following processes 1 to 5 as one cycle.
The magnetic characteristics of the encoder lattice (elastic member 14) and the output characteristics of the rotary encoder are measured every 30, 60, 90, and 120 cycles. 1. 1. Salt spray test: 5 hours (JIS, Z2371) Blowing: 1 hour (normal temperature) 3. Wet: 14 hours (50 ° C., 95% RH) 4. Blowing: 3 hours (50 ° C) Blast: 1 hour (normal temperature)

[0020]

According to the wheel bearing of the present invention, the rust-proofing layer is formed on the fitting surface of the rotating member on which the first seal plate provided with the elastic member serving as the encoder lattice is fitted. The rust prevention performance of the joint is improved, and the deformation of the seal plate due to rust can be prevented. Therefore, even when used in a severe environment, the rotation detection accuracy by detecting the encoder grating is maintained.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a wheel bearing according to an embodiment of the present invention.

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 conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Inner member 1b ... Fitting surface 2 ... Outer member 3 ... Rolling element 5 ... Sealing device 11 ... First seal plate 12 ... Second seal plate 11a, 12a ... Cylindrical portion 11b, 12b ... Standing plate portion 14 elastic member 16a-16c lip 21 rust-proofing layer N, S magnetic pole

Claims (5)

[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 seal device, the seal 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 each have a circumferential portion. The first 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 magnetic member is alternately formed in the circumferential direction with the elastic member, and the second seal plate integrally includes a side lip sliding on the upright plate portion and a radial lip sliding on the cylindrical portion. The cylindrical portion of the second seal plate and the tip of the standing plate portion of the first seal plate face each other with a slight radial interval, and the first seal plate of the rotating member is fitted. A bearing for a wheel, wherein a rust-proofing layer is formed on a fitting surface to be formed. 2. The wheel bearing according to claim 1, wherein a rustproofing layer is formed on an exposed portion of the rotating side member to which the first seal plate is fitted. 3. The wheel bearing according to claim 1, wherein the rust-proofing layer is a metal plating layer. 4. The wheel bearing according to claim 3, wherein the metal plating layer is zinc, nickel, or a plating layer of zinc and nickel. 5. The wheel bearing according to claim 1, wherein the first seal plate is formed of a magnetic material and a steel plate having rust prevention properties.