JP2003222150A - Magnetic encoder and bearing for wheel provided with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic encoder by which a large magnetic force can be obtained, and which is strong against peeling due to a temperature change. <P>SOLUTION: The magnetic encoder 20 is provided with a magnetic pole forming ring 22 and an expansion and contraction absorbing layer 23 provided on a mounting face to the other member of the magnetic pole forming ring 22. The magnetic pole forming ring 22 is a member in which a magnetic pole is formed alternately in the circumference and comprises a plastic magnet, a sintered magnet or a rubber magnet. The expansion and contraction absorbing layer 23 is an elastically expandable and contractive layer and an elastic adhesive or a rubber material or the like is used. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic encoder which constitutes a rotation detecting device for detecting the rotation speed of a rotating body such as a wheel, and a wheel bearing including the magnetic encoder.

[0002]

2. Description of the Related Art Conventionally, magnetic encoders using rubber magnets have been widely used as bearings for automobile wheels. In this type of magnetic encoder, an elastic member mixed with magnetic powder is fixed to a ring-shaped core metal by vulcanization adhesion, and magnetic poles are alternately formed in the circumferential direction. It is used as an encoder. A magnetic sensor is placed face-to-face with this via an air gap, and a rotation detection device for detecting the rotation speed of the wheel is configured. A magnetic encoder using a rubber magnet has an advantage that it can withstand a severe temperature environment and maintain its stickiness as follows. The temperature environment of the magnetic encoder when used for a wheel bearing is about −40 ° C. to + 120 ° C., and due to the difference in thermal expansion coefficient between the core metal and the rubber magnet, a large thermal expansion difference occurs in the natural state. Although it occurs, this difference in thermal expansion is absorbed by the expansion and contraction of rubber, and the problem of peeling of the magnetic encoder from the core metal does not occur.

[0003]

In the rubber magnet, the magnetic powder which can be kneaded is limited to the ferrite powder because of its compatibility with the rubber material, and the magnetic force which is the ability of the magnetic encoder, that is, the improvement of the residual magnetic flux density is limited. There is. The magnetic force of the rubber magnet depends on the amount of the magnetic powder, and if the mixing ratio of the magnetic powder to the rubber material is increased, the residual magnetic flux density can be improved, but the elasticity of the rubber magnet decreases and the temperature changes when the temperature changes. It becomes impossible to absorb the difference in thermal expansion due to the elasticity of. Therefore, the problem of peeling occurs. To meet the demand for increased magnetic force,
It is conceivable to use a plastic magnet or a sintered magnet. The plastic magnet is made by mixing magnetic powder with plastic, but it has no inconvenience in terms of material compatibility,
Neodymium-based or samarium-based rare earth having excellent magnetic force can be used as the magnetic powder. However, since plastic magnets and sintered magnets have almost no elasticity, they do not absorb the difference in thermal expansion and contraction when the temperature changes, and peeling occurs at the bonding surface between the magnetic encoder and the cored bar.

The object of the present invention is to obtain a large magnetic force,
It is an object of the present invention to provide a magnetic encoder and a magnetic encoder with a cored bar that are strong against peeling due to temperature changes. Another object of the present invention is to provide a wheel bearing device capable of effectively utilizing the features of the magnetic encoder of the present invention and capable of highly reliable wheel speed detection.

[0005]

A magnetic encoder according to the present invention is provided with a magnetic pole forming ring having magnetic poles alternately formed in the circumferential direction, and an elastic surface provided on a mounting surface of the magnetic pole forming ring to another member. And a stretchable absorption layer capable of stretching. This magnetic encoder may be of either an axial type or a radial type. The magnetic encoder having this structure is used by being attached to another member on the surface of the expansion / contraction absorption layer, and the expansion / contraction absorption layer is interposed between the magnetic pole forming ring and the other member. When a temperature change occurs, even if there is a difference in thermal expansion due to the difference in thermal expansion coefficient between the magnetic pole forming ring and the other members, the expansion and contraction absorbing layer interposed between the two expands elastically To be done. Therefore, the magnetic encoder is prevented from peeling off from other members. As described above, since the expansion / contraction absorption layer absorbs the difference in thermal expansion / contraction, the magnetic pole forming ring does not need elasticity, has a high degree of freedom in material selection, and can freely select a material having a strong magnetic force. For example, as the magnetic pole forming ring, a plastic magnet, a sintered magnet, or a rubber magnet having an increased content of magnetic powder can be used. For rotation detection,
By arranging the magnetic sensor so as to face the magnetic pole forming ring via the air gap, each magnetic pole is detected by the magnetic sensor as the magnetic encoder rotates, and rotation is detected as a pulse.

The expansion / contraction absorbing layer may be attached to the magnetic pole forming ring or other member via an adhesive means such as an adhesive. It is preferably a layer made of a material having a function of joining with other members. As a result, it is not necessary to separately use an adhesive agent or the like, and the magnetic pole forming ring and other members can be bonded with a single layer, and the configuration and the assembly process are simplified. When the stretchable absorption layer itself is a layer made of a material having a bonding function, an elastic adhesive can be used as the stretchable absorption layer. The elastic adhesive is an adhesive that has fluidity when bonded and has rubber-like elasticity in a cured state. Since the adhesive layer of the elastic adhesive cures into a rubber-like shape, when it is used as the expansion and contraction absorbing layer, it can follow a rapid temperature change and prevent peeling of the adhesive layer. Various types of elastic adhesives are commercially available, and for example, an epoxy resin containing a silicone-modified polymer can be used. The elastic adhesive made of this material has tough and flexible characteristics, can be used for materials such as stainless steel and aluminum that are difficult to adhere, and is hard to peel off even under repeated use conditions of vibration and cold heat.

In the magnetic encoder of each of the above configurations of the present invention, the mounting surface of the magnetic pole forming ring to the other member is:
It may be a flat surface that is simply attached by adhesion or the like, but it may be a fitting surface that is press-fitted to the outer circumference of another member, for example, a cylindrical fitting surface. In the case of press-fitting, a material that is not easily elastically deformed causes a problem of breakage, but since the expansion and contraction absorbing layer has an action of absorbing a dimensional change at the time of press-fitting, breakage can be prevented. That is, when the magnetic pole forming ring is press-fitted, the expansion-contraction absorption layer serves as both a function of absorbing a difference in thermal expansion and contraction and a function of absorbing a dimensional change due to press-fitting.

A magnetic encoder with a cored bar of the present invention is a ring-shaped cored bar which is the above-mentioned other member in addition to the magnetic encoder of any one of the magnetic encoders of the present invention except the one to be press-fitted. Is adhered to the expansion and contraction absorbing layer. The core metal may be used for any purpose. For example, the core metal is used for maintaining the shape of the magnetic pole forming ring, but is also used for attaching to the device using the magnetic encoder by fitting or for sealing the device using the magnetic encoder. Can be The core metal is, for example,
The L-shaped cross section may include a cylindrical portion and a standing plate portion that extends from one end of the cylindrical portion to the outer periphery, and the magnetic encoder may be provided on the outward surface of the standing plate portion.

The wheel bearing of the present invention comprises the magnetic encoder or the magnetic encoder with a cored bar of any one of the above configurations of the present invention. Wheel bearings are subject to severe temperature environments, and the space for arranging the magnetic encoder is often limited, so a strong magnetic flux density is required for the magnetic pole forming ring to enable highly reliable rotation detection with a compact configuration. To be done. Therefore, the unique effect that a large magnetic force is obtained by the magnetic encoder of the present invention and is strong against peeling due to temperature change is effective.

This wheel bearing includes, for example, an outer member having a double row rolling surface formed on the inner peripheral surface, and an inner member having a rolling surface facing the rolling surface of the outer member. , A double row rolling element interposed between these two rolling surfaces, a wheel mounting flange is provided on a rotation side member of the outer member or the inner member, and the wheel is rotatable with respect to the vehicle body. And a sealing device for sealing an annular space between the outer member and the inner member. The sealing device is a first bearing having an L-shaped cross section fitted to the rotating member. 1 seal plate,
A second L-shaped section that faces the first seal plate and is fitted to a fixed member of the outer member or the inner member.
And a side lip slidably contacting the standing plate portion of the first seal plate and a radial lip slidably contacting the cylindrical portion of the first seal plate are fixed to the second seal plate, and the upright side of the first seal plate is secured. It is assumed that the magnetic encoder is attached to the outward surface of the plate portion. In this case, since the magnetic encoder can be incorporated as a part of the bearing seal device, the magnetic encoder can be installed compactly with good assembling. Since the first and second sealing plates face each other and the side lip and the radial lip are in sliding contact with each other, the sealing device has excellent sealing performance. When the magnetic encoder is provided as a part of the seal device as described above, in order to obtain the effect of the above-described good assembling property, it is desirable that a large air gap be obtained, and therefore a strong magnetic force be obtained. . In response to such a demand, according to the magnetic encoder of the present invention, a strong magnetic force is obtained, a large air gap is obtained, and in the wheel bearing having the above configuration, the assembling property is good, and the effect of compactification is more effective. To be the target.

[0011]

1 is a block diagram of a first embodiment of the present invention.
3 to FIG. FIG. 1 is a sectional view of a wheel bearing provided with the magnetic encoder of this embodiment. This wheel bearing has an inner member 1 and an outer member 2, a plurality of rolling elements 3 housed between these inner and outer members 1 and 2, and an end annular space between the inner and outer members 1 and 2. And sealing devices 5 and 13 for sealing. The sealing device 5 at one end has an axial type magnetic encoder 20. The inner member 1 and the outer member 2 are rolling surfaces 1a, 2a of the rolling element 3.
And each rolling surface 1a, 2a is formed in a groove shape. The inner member 1 and the outer member 2 are members on the inner peripheral side and members on the outer peripheral side that are rotatable with respect to each other via the rolling elements 3, and even if the bearing inner ring and the bearing outer ring are independent. good. Further, the inner member 1 may be a shaft. The rolling elements 3 are balls or rollers, and balls are used in this example.

This wheel bearing is a double-row rolling bearing, more specifically a double-row angular contact ball bearing, the inner ring of which is fitted to the hub ring 6 and the outer diameter of the end of the hub ring 6. And a separate inner ring 1A. A rolling surface 1a of each rolling element row is formed on the hub wheel 6 and the separate body wheel 1A.

The hub wheel 6 has a constant velocity universal joint (not shown).
, The outer ring of the joint is connected, and a wheel (not shown) is attached to the flange portion 6a of the hub wheel 6 with a bolt 8. The other end of the constant velocity universal joint, for example, the inner ring, is connected to a drive shaft (not shown). The outer member 2 is a flange 2
It is composed of a bearing outer ring having b and is attached to a housing (not shown) composed of a knuckle or the like. The outer member 2 is assumed to have raceway surfaces 2a, 2a for both rolling element rows. The rolling elements 3 are held by the cage 4 for each row. The annular space between the inner member 1 and the outer member 2 has one end, that is, the end portion on the axle center side, sealed by the sealing device 5 described above. The end of the annular space between the outer member 2 and the hub wheel 6 is
It is sealed by another sealing device 13.

FIG. 2 shows the sealing device 5 on an enlarged scale. The sealing device 5 has first and second annular sealing plates 11 and 12 attached to the inner member 1 and the outer member 2, respectively. These seal plates 11 and 12 are made of steel plates, and are attached to the inner member 1 and the outer member 2 by being press-fitted. Both seal plates 11 and 12 are formed in an L-shaped cross-section and are formed of cylindrical portions 11a and 12a and standing plate portions 11b and 12b, respectively, 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 to form a slinger. The first seal plate 11 is a magnetic body. First seal plate 11
The standing plate portion 11b is arranged on the outer side of the bearing, and the axial type magnetic encoder 20 is fixed to the outer side surface thereof. The first seal plate 11 is a member serving as a core metal for the magnetic encoder 20, and the first seal plate 11 and the magnetic encoder 20 form a magnetic encoder 21 with a core metal. The magnetic encoder 20 will be described in detail later.

The second seal plate 12 is the first seal plate 1.
One side lip 16a that slidably contacts the standing plate portion 11b and radial lips 16b and 16c that slidably contact the cylindrical portion 11a are integrally provided. These lips 16a to 16c are provided as a part of the elastic member 16 vulcanized and bonded to the second seal plate 12. The second seal plate 12 is one in which the elastic member 16 is held in the fitting portion with the outer member 2 which is the fixed member. The cylindrical portion 12a of the second seal plate 12 and the first
The end face of the upright plate portion 11b of the seal plate 11 is faced with a slight radial gap, and the gap forms a labyrinth seal. Radial lip 16c on the standing plate 11b side
Has increased the contact pressure with the cylindrical portion 11a by the elastic ring 14 provided on the outer circumference.

The magnetic encoder 20 includes a magnetic pole forming ring 2
2 and the expansion / contraction absorbing layer 23 provided on the mounting surface of the magnetic pole forming ring 22 to the seal plate 11. As shown in FIG. 3, the magnetic pole forming ring 22 is a multi-pole magnet in which magnetic poles N and S are alternately formed in the circumferential direction, and is a ring-shaped plate member. The magnetic poles N and S have a pitch circle diameter (PC
In D), it is formed to have a predetermined pitch p. In FIG. 2, the expansion / contraction absorption layer 23 is a layer that can elastically expand and contract. That is, the expansion / contraction absorbing layer 23 is a layer that is provided on the attachment surface of the magnetic pole forming ring 22 to the other member (the first seal plate 11 in this embodiment) and fixed to the other member. It is a layer that elastically allows a deviation due to a difference in thermal expansion coefficient between the forming ring 22 and the other member. The magnetic pole forming ring 22 of the magnetic encoder 20
Further, by arranging a magnetic sensor (not shown) facing the axial direction via a predetermined air gap, a rotation detecting device for detecting the wheel rotation speed is configured. The magnetic sensor is attached to the vehicle body. The output of the magnetic sensor is used, for example, to control the antilock brake system.

The magnetic pole forming ring 22 of the magnetic encoder 20
Is composed of, for example, either a plastic magnet, a sintered magnet, or a rubber magnet. The plastic magnet is a magnet in which magnetic powder is mixed in plastic, and ferrite magnet, neodymium-based or samarium-based rare earth magnet powder is used as the magnetic powder.
The sintered magnet is, for example, magnetic powder obtained by crushing a raw material alloy,
The powder is compacted by pressing in a magnetic field so that the particles are oriented in the same direction, and magnetized after sintering. The rubber magnet is a rubber material mixed with magnetic powder, and in this case, ferrite magnet powder is used as the magnetic powder. When the rubber magnet is used, a rubber magnet having a higher content of magnetic powder than that of the rubber magnet in the conventional magnetic encoder having no expansion and contraction absorbing layer 23 is used.

The expansion and contraction absorbing layer 23 may be any layer that can elastically expand and contract, and may be an elastic adhesive coating layer, a rubber material layer, or an elastic synthetic resin layer. The rubber material layer and the synthetic resin layer may be coating layers or may be plate-like or sheet-like members attached to the magnetic pole forming ring 22 with an adhesive or the like. The expansion / contraction absorbing layer 23 is preferably a layer made of a material having a function of joining the magnetic pole forming ring 22 and another member (first seal plate 11) that is a member for mounting the same to the magnetic pole forming ring 22. It is used as an adhesive coating layer. As the elastic adhesive, various commercially available ones can be used. For example, an epoxy resin mixed with a silicon-modified polymer, particularly a synthetic resin 10
The content of 0% is used. A special silicone modified polymer is used as the silicone modified polymer.
Further, as the elastic adhesive obtained by blending this epoxy resin with a silicon-modified polymer, a two-component elastic adhesive, that is, one that mixes and applies two liquids at the time of adhesion is used.

According to this structure, since the magnetic encoder 20 is provided with the expansion / contraction absorbing layer 23, when the temperature changes, the thermal expansion difference is caused by the thermal expansion coefficient difference between the magnetic pole forming ring 22 and the first seal plate 11. Even if they occur, both 22, 11
The elastic absorption layer 23 interposed between the elastic layers expands and contracts elastically to be absorbed. Therefore, the magnetic pole forming ring 22 is prevented from peeling off from the first seal plate 11. As described above, since the expansion / contraction absorption layer 23 absorbs the thermal expansion / contraction difference, the magnetic pole forming ring 22 does not need elasticity, has a high degree of freedom in material selection, and can freely select a material having a strong magnetic force. As described above, as the magnetic pole forming ring 22, a plastic magnet or a sintered magnet may be used, or a rubber magnet having an increased blending amount of magnetic substance powder may be used, thereby enhancing the magnetic characteristics. it can. That is, in the case of a plastic magnet, a neodymium-based or samarium-based rare earth magnet powder can be used as the magnetic material powder without being limited in compatibility with the magnetic material powder. The residual magnetic flux density of neodymium-based or samarium-based plastic magnets is more than twice that of ferrite rubber magnets. With sintered magnets,
Further excellent residual magnetic flux density can be obtained. However, neodymium-based or samarium-based plastic magnets have the drawback that they are weak at high temperatures and easily rusted, so in some cases it is preferable to perform a coating treatment for rust prevention.

Further, in this embodiment, the expansion / contraction absorbing layer 23.
Since the elastic adhesive is used as the above, the magnetic pole forming ring 22 and the first seal plate 11 can be bonded with a single layer, and the configuration and the assembly process of the magnetic encoder 21 with a cored bar are simplified. When the expansion / contraction absorption layer 23 itself is made of a material having a bonding function, an elastic adhesive can be used as the expansion / contraction absorption layer 23. The elastic adhesive is an adhesive that has fluidity when bonded and has rubber-like elasticity in a cured state. When the epoxy adhesive compounded with the silicone-modified polymer is used as the elastic adhesive, it has tough and flexible characteristics. Further, even if the first seal plate 11 is made of a material such as stainless steel which is hard to adhere, it can be used, and is difficult to peel off even under repeated use conditions of vibration and cold heat.

The wheel bearing of this embodiment has a magnetic encoder 20 as a part of the seal device 5 at the end of the bearing.
, The magnetic encoder 20 can be installed compactly. The sealing device 5 has excellent sealing performance because the first and second sealing plates 11 and 12 face each other and the side lip 16a and the radial lips 16b and 16c are in sliding contact with each other.

FIG. 4 shows a magnetic encoder 20A according to another embodiment of the present invention. This magnetic encoder 20
In A, the magnetic pole forming ring 22A is formed in a L-shaped cross section including a cylindrical portion 22Aa and a standing plate portion 22Ab.
Aa is another member, for example, the inner member 1 of the wheel bearing of FIG.
Is fitted and attached to the outer periphery of. This fitting may be press fitting. The expansion and contraction absorbing layer 23 is provided on the inner diameter surface of the cylindrical portion 22Aa. The magnetic pole forming ring 22A is a multi-pole magnet in which the standing plate portions 22Ab do not have magnetic poles alternately formed in the circumferential direction. The cylindrical portion 22Aa of the magnetic pole forming ring 22A may have the same magnetic pole as that of the standing plate portion 22Ab, but the cylindrical portion 22Aa has no magnetic pole, that is, is not magnetized. The material of the magnetic pole forming ring 22A is a plastic magnet or a sintered magnet. These plastic magnets or sintered magnets have been described in the above embodiment. The expansion / contraction absorbing layer 23 is an adhesive layer of an elastic adhesive, or a plate-shaped or sheet-shaped one. In the case of a plate or sheet, the magnetic encoder 20A may be attached to the outer diameter surface of another member by press fitting.

The magnetic encoder 20A is attached to the inner member 1 of the wheel bearing shown in FIGS. 1 and 2, instead of the first seal plate 11 and the magnetic encoder 20, for example. In that case, the second seal plate 12 is attached to the standing plate portion 22Ab and the cylindrical portion 22Aa of the magnetic pole forming ring 22A.
The respective lips 16a to 16c are brought into sliding contact with each other.

In the case of the magnetic encoder 20A having this structure,
When used as a wheel bearing as described above, the magnetic pole forming ring 22A can be used as a slinger. Therefore, the structure of the seal device with the magnetic encoder is further simplified. The expansion / contraction absorbing layer 23A absorbs a difference in thermal expansion between the magnetic pole forming ring 22A and the inner member 1 for mounting the magnetic pole forming ring 22A, and can prevent the magnetic pole forming ring 22A from falling off due to peeling. When the magnetic pole forming ring 22A is attached to the inner member 1 by press fitting, the expansion and contraction absorbing layer 23A can absorb the dimensional change due to the press fitting, and the magnetic pole forming ring 22A is made of a material that is difficult to deform. Even in this case, the magnetic pole forming ring 22A can be attached by press fitting without being damaged.

FIG. 5 shows a wheel bearing according to still another embodiment of the present invention. This embodiment is provided with a radial type magnetic encoder 20B. This wheel bearing seals an inner member 51 and an outer member 52, a plurality of rolling elements 53 housed between these inner and outer members 51, 52, and an end annular space between the inner and outer members 51, 52. And a magnetic encoder 20B different from the seal device 55 is provided at one end.
The inner member 51 and the outer member 52 have rolling surfaces of the rolling elements 53, and each rolling surface is formed in a groove shape. The inner member 51 is composed of a pair of split type inner rings 51A and 51B, and a fixed axle (not shown) fitted to the inner diameter surfaces of the inner rings 51A and 51B. The outer member 52 serves as a rotating wheel, and is an integral bearing outer ring that also serves as a hub wheel. The magnetic encoder 20B is fitted on the outer periphery of one end of the outer member 52.

The magnetic encoder 20B comprises a magnetic pole forming ring 22B and an expansion / contraction absorbing layer 23B provided on the inner diameter surface thereof, as shown in an enlarged view in FIG. The magnetic pole forming ring 22B has a ring shape whose thickness in the radial direction is smaller than its width in the axial direction, and has, for example, a cylindrical shape. The magnetic pole forming ring 22B has magnetic poles N and S formed alternately in the circumferential direction, and the magnetic fluxes of the magnetic poles N and S are generated in the radial direction. The material of the magnetic pole forming ring 22B is a plastic magnet, a sintered magnet, or a rubber magnet. These plastic magnets, sintered magnets, and rubber magnets have been described in the above embodiment.
The expansion and contraction absorbing layer 23B is an adhesive layer of an elastic adhesive, or a plate-shaped or sheet-shaped one. In the case of a plate shape or a sheet shape, the magnetic encoder 20B may be attached to the outer diameter surface of another member, that is, the outer diameter surface of the outer member 52 in this wheel bearing, by press fitting. Magnetic encoder 2
A magnetic sensor (not shown) for 0B is provided on a fixed side member such as a knuckle, which faces the magnetic pole forming ring 22B in the radial direction via a predetermined air gap.

Also in this structure, the expansion and contraction absorbing layer 23B is
It is possible to absorb the difference in thermal expansion between the magnetic pole forming ring 22B and the outer member 52 that is a member for mounting the magnetic pole forming ring 22B, and prevent the magnetic pole forming ring 22B from falling off due to peeling. When the magnetic pole forming ring 22B is attached to the outer member 52 by press fitting, the expansion and contraction absorbing layer 23B can absorb the dimensional change due to the press fitting, and the magnetic pole forming ring 22B is not easily deformed. Even in this case, the magnetic pole forming ring 22B can be attached by press fitting without being damaged. Thus, in the radial type magnetic encoder 20B, when the expansion and contraction absorbing layer 23B is provided, the core metal can be omitted,
The magnetic encoder 20B has a simple structure.

The case where the first embodiment is applied to the third-generation wheel bearings and the case where the first embodiment is applied to the second-generation wheel bearings have been described. The wheel bearing of the present invention can be applied to any one of the first to fourth generation wheel bearings. Further, it can be applied to a wheel-use bearing in which either the inner member or the outer member is on the rotation side. Further, in the description of each of the above-described embodiments, the case where the magnetic encoder 20 is provided for the wheel bearing has been described, but the magnetic encoder 20 can be generally used for rotation detection of the rotating member. The magnetic pole forming ring 2 described in the above embodiment
The material, shape, etc. of 2 and the expansion / contraction absorption layer 23 can be applied regardless of the machine to which the magnetic encoder 20 is attached.

[0029]

According to the magnetic encoder of the present invention, a magnetic pole forming ring in which magnetic poles are alternately formed in the circumferential direction and a mounting surface of the magnetic pole forming ring to another member are elastically expandable and contractible. Since it has a flexible expansion and contraction absorbing layer, a large magnetic force can be obtained, and it is strong against peeling due to temperature change. The wheel bearing of the present invention can effectively utilize the features of the magnetic encoder of the present invention, and can perform highly reliable wheel speed detection.

[Brief description of drawings]

FIG. 1 is a sectional view of a wheel bearing including an axial magnetic encoder according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of a portion II surrounded by a chain line of FIG.

FIG. 3 is a partially enlarged front view of the magnetic encoder.

FIG. 4 is a sectional view of an axial type magnetic encoder according to another embodiment of the present invention.

FIG. 5 is a sectional view of a wheel bearing provided with a radial type magnetic encoder according to another embodiment of the present invention.

FIG. 6 is a partially enlarged sectional view of the magnetic encoder.

[Explanation of symbols]

1 ... Inner member (other member) 2 ... Outer member 3 ... rolling elements 5 ... Sealing device 11 ... First seal plate (core metal) 12 ... Second seal plate 16 ... Elastic member 16a ... side lip 16b, 16c ... Radial lip 20 ... Magnetic encoder 21 ... Magnetic encoder with core metal 22 ... Magnetic pole forming ring 23 ... Stretchable absorption layer 20A, 20B ... Magnetic encoder 22A, 22B ... Magnetic pole forming ring 23A, 23B ... Stretchable absorption layer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Satoshi Goto             Entier, 1578 Higashi-Kaizuka, Iwata City, Shizuoka Prefecture             Nu Co., Ltd. F term (reference) 2F077 AA41 AA42 NN04 NN18 VV02                       VV11 VV31 VV33                 3J101 AA02 AA32 AA43 AA54 AA62                       AA72 BA53 BA64 BA73 FA31                       GA03

Claims (8)

[Claims] 1. A magnetic pole forming ring in which magnetic poles are alternately formed in the circumferential direction, and an elastic absorbing layer which is provided on a mounting surface of the magnetic pole forming ring to another member and is elastically expandable and contractible. Magnetic encoder. 2. The magnetic encoder according to claim 1, wherein the expansion / contraction absorbing layer is a layer made of a material having a function of joining the magnetic pole forming ring and the other member. 3. The magnetic encoder according to claim 2, wherein the expansion / contraction absorption layer is an elastic adhesive. 4. The magnetic encoder according to claim 3, wherein the elastic adhesive is an epoxy resin mixed with a silicon-modified polymer. 5. The magnetic encoder according to claim 1, wherein a mounting surface of the magnetic pole forming ring to the other member is a fitting surface that is press-fitted to the outer periphery of the other member. . 6. A magnetic encoder with a cored bar, wherein a ring-shaped cored bar serving as the other member is fixed to the expansion / contraction absorption layer in the magnetic encoder according to claim 1. 7. A bearing for a wheel provided with the magnetic encoder according to claim 1, or the magnetic encoder with a cored bar according to claim 6. 8. The wheel bearing comprises: an outer member having a double row rolling surface formed on the inner peripheral surface; and an inner member having a rolling surface facing the rolling surface of the outer member. , A double row rolling element interposed between these two rolling surfaces, a wheel mounting flange is provided on a rotation side member of the outer member or the inner member, and the wheel is rotatable with respect to the vehicle body. A bearing for a wheel that is supported by a sealing device that seals an annular space between the outer member and the inner member, the sealing device having a L-shaped cross section fitted to the rotating member. 1 seal plate, and a second seal plate facing the first seal plate and having an L-shaped cross section that is fitted to a fixed member of the outer member or the inner member. The side lip slidingly contacting the standing plate portion of the first seal plate and the radial lip slidingly contacting the cylindrical portion are the second seals. It is fixed to Le plate, the surface of the outward of the upright plate portion of the first seal plate, a wheel bearing according to claim 7, fitted with the magnetic encoder.