JP4052037B2 - Magnetic encoder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic encoder that detects the rotational speed of a shaft.
[0002]
[Prior art]
Conventionally, this type of magnetic encoder is used, for example, to detect the speed of an automobile.
[0003]
Further, a magnetic encoder having a sealing function for sealing a rotating shaft is known. Such a conventional magnetic encoder will be described with reference to FIGS.
[0004]
FIG. 8 is a schematic sectional view of a magnetic encoder provided with a sealing device according to the prior art. FIG. 9 is a schematic cross-sectional view of a slinger in a conventional magnetic encoder.
[0005]
As shown in FIG. 8, an annular gap between the shaft and the housing is sealed and rotated by a magnetic encoder 100 mounted on a rotating shaft (not shown) and a sealing device 200 mounted on a housing (not shown). Systems for detecting the rotational speed of a shaft are known.
[0006]
The magnetic encoder 100 includes a slinger 110 as an annular member and a magnetic rubber portion 120.
[0007]
The slinger 110 includes a cylindrical portion 110a attached to the shaft, and a flange portion 110b extending from the end portion of the cylindrical portion 110a toward the outer diameter side. The magnetic rubber portion 120 is baked and fixed to the outside of the flange portion 110b of the slinger 110 by molding.
[0008]
The sealing device 200 includes a metal ring 201 fitted into the housing, and a seal portion 202 fixed to the metal ring 201 by baking. The seal portion 202 is provided so as to be slidable with respect to the slinger 110 of the magnetic encoder 100 and includes a plurality of seal lips forming a seal surface on the slinger 110.
[0009]
Thus, the annular gap between the rotating shaft and the housing is sealed by mounting the magnetic encoder 100 on the rotating shaft (not shown) and mounting the sealing device 200 on the housing (not shown). When the magnetic encoder 100 rotates with the rotation of the shaft, the rotational speed of the rotating shaft is detected by the sensor 150 disposed opposite to the magnetic encoder 100.
[0010]
Here, in order to bake and fix the magnetic rubber portion 120 to the slinger 110 by molding, vulcanization molding is performed. In order to fix the magnetic rubber to the slinger 110 by this vulcanization molding, a process of applying an adhesive to the surface of the slinger 110 is necessary.
[0011]
In order to perform the adhesive and the non-treatment on a large amount of the slinger 110 at the same time, a method of immersing the slinger 110 in the adhesive is generally used.
[0012]
However, as shown in FIG. 9, a portion of the slinger 110 where the magnetic rubber portion 120 is baked and fixed, that is, the flange portion 110b has a flat plate shape. Therefore, when the slinger 110 is immersed in the adhesive, as shown in FIG. 10, there are some in which the flat flange portions 110b are in close contact with each other.
[0013]
Depending on the type and concentration of the adhesive used, the flange portions 110b may be in close contact with each other, and may be baked and dried while the slinger 110 is adhered.
[0014]
If the adhesive is further coated in this state, the adhesive will not be applied to the surface of the sticking slinger 110. Therefore, when the magnetic rubber is vulcanized, the magnetic rubber applied to the slinger 110 will be removed. Bonding strength is weakened. For this reason, the magnetic rubber part 120 may be peeled off from the slinger 110.
[0015]
Therefore, in order to eliminate such a problem, when the slinger 110 is baked and dried with the adhesive sticking to each other, an operation of peeling the slinger 110 between the adhesives is applied or the sticking slinger 110 is defective. As a waste disposal. Therefore, waste of work and waste of defective products have occurred.
[0016]
As a virtual technology that eliminates these wastes, there is the one shown in FIG. FIG. 11 is a schematic cross-sectional view of a slinger in a magnetic encoder according to virtual technology.
[0017]
The slinger 115 shown in FIG. 11 includes a cylindrical portion 115a attached to the shaft, and a flange portion 115b extending from the end portion of the cylindrical portion 115a toward the outer diameter side. The slinger 115 includes a tapered portion 115c that is inclined outward at the tip of the flange portion 115b.
[0018]
If such a taper portion 115c is provided, the flange portions 115b can be contacted only by line contact even when the immersion treatment is performed in the adhesive. As shown in FIG. Can be prevented from making surface contact. This prevents the slinger from sticking to each other even when the adhesive dipping treatment and baking drying are repeated, and prevents the magnetic rubber part from peeling off due to insufficient application of the adhesive. It becomes possible to do.
[0019]
However, in order to ensure the magnetic characteristics as a magnetic encoder, the magnetic rubber portion needs to have a uniform thickness. Therefore, the flange portion of the slinger is required to be as flat as possible.
[0020]
Further, in order to provide the tapered portion 115c at the tip of the flange portion 115b, a bending process is usually required. In order to perform the bending process, the dimension from the taper to the tip (L in FIG. 11) is a slinger. About 1.5 times the plate thickness of the material is required.
[0021]
And in this part, since dripping arises by vulcanization molding of magnetic rubber, magnetic rubber is coat | covered inside a comparatively wide range of the front-end | tip.
[0022]
Therefore, as described above, as shown in FIG. 8, when the sealing device 200 is also used, the seal lip slides on the flange portion of the slinger. If the portion is covered, there is a problem that the seal lip and the magnetic rubber portion slide and the lip wear is promoted.
[0023]
In particular, it is difficult to avoid such inconveniences when there are restrictions on the dimensions in the radial direction.
[0024]
From the above, it is considered that it is insufficient to eliminate the problem that the slinger sticks when the slinger is immersed in the adhesive by providing a tapered portion at the tip of the flange portion of the slinger.
[0025]
[Problems to be solved by the invention]
As described above, in the prior art, when an annular member (slinger) is dipped in an adhesive, the annular members stick to each other, resulting in waste of work and waste of defective products.
[0026]
An object of the present invention is to provide a magnetic encoder that suitably prevents adhesion of annular members without impairing quality even when the annular members are immersed in an adhesive.
[0027]
[Means for Solving the Problems]
In order to achieve the above object, the magnetic encoder of the present invention is characterized in that a minute protrusion is provided on the surface of the flange portion of the annular member on the side where the magnetic rubber portion is baked.
[0028]
By providing such minute protrusions, when the adhesive is applied to the annular member, the flange portions of the annular member are in surface contact over a wide range even if the annular member is immersed in the adhesive. Can be prevented.
[0029]
In particular, if the minute projections are projections continuously provided over the entire circumference of the tip of the flange portion, the flange portions can be in point contact or line contact, and surface contact can be prevented.
[0030]
Further, since the protrusions are minute, the magnetic rubber portion baked and fixed to the flange portion by molding can be made to have a substantially uniform thickness, and the magnetic properties are not impaired.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Exemplary embodiments of the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. Absent.
[0032]
(First embodiment)
A magnetic encoder according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic cross-sectional view of a magnetic encoder provided with a sealing device according to a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the magnetic encoder according to the first embodiment of the present invention. FIG. 3 is a schematic sectional view of a slinger in the magnetic encoder according to the first embodiment of the present invention. FIG. 4 is a top view of the magnetic rubber portion in the magnetic encoder according to the first embodiment of the present invention.
[0033]
As shown in FIG. 1, in the magnetic encoder 10 according to the present embodiment, the magnetic encoder 10 is mounted on the outer periphery of a rotating shaft (not shown), and the sealing device 20 is mounted on the inner periphery of a shaft hole of a housing (not shown). Thus, the annular gap between the shaft and the housing is sealed, and the system is used as a system for detecting the rotational speed of the rotating shaft and the like.
[0034]
As a more specific application example, a vehicle speed sensor for detecting the speed of an automobile is preferably used by being attached to an axle bearing device (hub bearing).
[0035]
The magnetic encoder 10 includes a slinger 11 and a magnetic rubber portion 12 as an annular member.
[0036]
The slinger 11 includes a cylindrical portion 11a attached to the rotation shaft, and a flange portion 11b extending from the end of the cylindrical portion 11a toward the outer diameter side. The magnetic rubber portion 12 is baked and fixed to the outside of the flange portion 11b of the slinger 11 by molding.
[0037]
The magnetic rubber portion 12 is made of, for example, a magnetizable rubber material in which ferrite is dispersed, and as shown in FIG. 4, the magnetic rubber portion 12 is multi-pole so that the magnetic poles NS alternate in the circumferential direction.
[0038]
The sealing device 20 includes a metal ring 21 fitted to the housing, and a seal portion 22 that is baked and fixed to the metal ring 21 by molding. The seal portion 22 is slidably provided with respect to the flange portion 11b of the slinger 11 of the magnetic encoder 10, and a first seal lip 22a that forms a seal surface on the flange portion 11b, and a cylindrical portion of the slinger 11 The cylindrical portion 11a is provided with a second seal lip 22b and a third seal lip 22c that are slidable with respect to the cylinder 11a.
[0039]
Thus, the annular gap between the rotating shaft and the housing is sealed by mounting the magnetic encoder 10 on the rotating shaft (not shown) and mounting the sealing device 20 on the housing (not shown).
[0040]
Further, a sensor 50 for detecting the rotational speed of the rotating shaft and the like is provided at a position facing the magnetic rubber portion 12.
[0041]
In this sensor 50, the magnetic rubber portion 12 rotates with the rotation of the rotating shaft, so that the position of the surface of the magnetic rubber portion 12 moves, and the magnetic field from the magnetic rubber portion 12 having multiple magnetic poles moves. Therefore, the rotation speed is detected by detecting the change.
[0042]
As a more specific example, a magnetoresistive effect element can be used as the sensor 50, and the rotational speed of the rotating shaft and the like can be detected based on the change in the magnetization direction by the magnetic rubber portion 12.
[0043]
Next, the slinger 11 that is a feature of the present embodiment will be described with reference to FIG.
[0044]
In the present embodiment, the minute protrusion 11c is provided on the side where the magnetic rubber portion 12 is baked at the tip of the flange portion 11b of the slinger 11. The minute projections 11c are continuously provided over the entire circumference of the tip of the flange portion 11b. However, a plurality of microprojections can be provided independently.
[0045]
The minute protrusions 11c are formed by press molding.
[0046]
In FIG. 3 (P), an enlarged view of the minute protrusion 11c is shown. By forming the minute projections 11c by press molding, as shown in FIG. 3 (P), the root width L1 of the projections is set to 0.3 times or less of the material plate thickness, and the tip width L2 of the projections is set to the material plate thickness. The height H1 of the protrusion was about 0.1 times the thickness of the material plate. Further, the width L3 of the sag portion can be set to about 0.7 times the thickness of the material plate, and this portion can be set to a level equivalent to the coating size of the magnetic rubber.
[0047]
As described above, in this embodiment, even if a large amount of slinger is immersed in the adhesive by providing the minute protrusions 11c over the entire circumference at the tip of the flange portion 11b of the slinger 11, the flange portion of the slinger 11 11b does not make surface contact, but is point contact or line contact.
[0048]
Thereby, it can prevent that the flange parts adhere and are baked and dried, and it can prevent that slinger adheres.
[0049]
Therefore, it is not necessary to remove the sticking slinger or to dispose of it.
[0050]
In addition, since the protrusions are very small, the flat portion of the flange portion 11b can be sufficiently secured, so that the thickness of the magnetic rubber portion 12 can be made uniform and the magnetic characteristics as the encoder can be secured.
[0051]
Further, since the sagging portion is also small, the range of the magnetic rubber film coated on the inside of the flange portion 11b is narrow, and when the sealing device 20 is mounted, the first seal lip 22a and the magnetic rubber slide. And can maintain a stable sealing function.
[0052]
Further, since the protrusions are very small, the flow of magnetic powder such as ferrite contained in the magnetic rubber is smooth and the magnetic powder is uniformly dispersed during the vulcanization molding of the magnetic rubber.
[0053]
(Second Embodiment)
5 to 7 show a second embodiment of the present invention. In the said 1st Embodiment, the structure in the case of providing the protrusion provided in the flange part of a slinger at the front-end | tip of a flange part was shown. In the present embodiment, a configuration in the case where this protrusion is provided near the root of the flange portion will be described.
[0054]
Since the configuration other than the slinger is the same as that of the first embodiment, description thereof will be omitted as appropriate.
[0055]
FIG. 5 is a schematic cross-sectional view of a magnetic encoder provided with a sealing device according to a second embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of a magnetic encoder according to a second embodiment of the present invention. FIG. 7 is a schematic sectional view of a slinger in the magnetic encoder according to the second embodiment of the present invention.
[0056]
Also in the magnetic encoder 30 according to the present embodiment, as in the first embodiment, the sealing device 20 is attached to seal the annular gap between the shaft and the housing, and the rotating shaft. It is used as a system for detecting the rotational speed of the slab.
[0057]
The magnetic encoder 30 includes a slinger 31 and a magnetic rubber portion 32 as an annular member. Since the magnetic rubber portion 32 is the same as that in the first embodiment, the description thereof is omitted.
[0058]
The slinger 31 includes a cylindrical portion 31a attached to the rotation shaft, and a flange portion 31b extending from the end portion of the cylindrical portion 31a toward the outer diameter side. The magnetic rubber portion 32 is baked and fixed to the outside of the flange portion 31b of the slinger 31 by molding.
[0059]
And in this Embodiment, the microprotrusion 31c is provided in the base vicinity of the side by which the magnetic rubber part 32 in the flange part 31b of the slinger 31 is baked. A plurality of the minute protrusions may be provided along the circumference, or may be provided so as to be continuous over the entire circumference.
[0060]
In FIG. 7 (Q), an enlarged view of the minute protrusion 31c is shown. The micro-projections 31c have a root width (radial width) D1 that is less than or equal to twice the material plate thickness (approximately 1 mm when the plate thickness is 0.6 mm as a guide), and the projection height H1 is 0 of the material plate thickness. About 1 time.
[0061]
As described above, since the minute protrusions 31c are also provided in the present embodiment, even if a large amount of slinger is immersed in the adhesive, the portions where the flange portions 31b of the slinger 31 are in surface contact with each other are small.
[0062]
Therefore, the adhesion between the slinger can be prevented as much as possible, and it is not necessary to remove the adhered slinger or to dispose of it.
[0063]
In addition, since the projections are very small, a sufficient plane portion of the flange portion 31b can be secured, so that the thickness of the magnetic rubber portion 32 can be made uniform and the magnetic characteristics as the encoder can be secured.
[0064]
Further, the minute protrusion 31c is near the root of the flange portion 31b, and a recess for forming the protrusion is formed on the inner side. This recess is separated from the region where the first seal lip 22a of the sealing device 20 slides. Therefore, the sealing performance is not impaired.
[0065]
Further, since the protrusions are very small, the flow of magnetic powder such as ferrite contained in the magnetic rubber is smooth and the magnetic powder is uniformly dispersed during the vulcanization molding of the magnetic rubber.
[0066]
【The invention's effect】
As described above, with the magnetic encoder of the present invention, even when an annular member, which is one of the constituent members of the magnetic encoder, is immersed in an adhesive, adhesion between the annular members is preferable without impairing quality. Can be prevented.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a magnetic encoder including a sealing device according to a first embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view of the magnetic encoder according to the first embodiment of the invention.
FIG. 3 is a schematic cross-sectional view of a slinger in the magnetic encoder according to the first embodiment of the invention.
FIG. 4 is a top view of a magnetic rubber portion in the magnetic encoder according to the first embodiment of the invention.
FIG. 5 is a schematic cross-sectional view of a magnetic encoder provided with a sealing device according to a second embodiment of the present invention.
FIG. 6 is a schematic cross-sectional view of a magnetic encoder according to a second embodiment of the invention.
FIG. 7 is a schematic cross-sectional view of a slinger in a magnetic encoder according to a second embodiment of the invention.
FIG. 8 is a schematic cross-sectional view of a magnetic encoder provided with a sealing device according to the prior art.
FIG. 9 is a schematic cross-sectional view of a slinger in a magnetic encoder according to the prior art.
FIG. 10 is a diagram for explaining a problem of a slinger in a magnetic encoder according to a conventional technique.
FIG. 11 is a schematic cross-sectional view of a slinger in a magnetic encoder according to a virtual technology.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Magnetic encoder 11 Slinger 11a Cylindrical part 11b Flange part 11c Microprotrusion 12 Magnetic rubber part 20 Sealing device 21 Metal ring 22 Seal part 22a First seal lip 22b Second seal lip 22c Third seal lip 30 Magnetic encoder 31 Slinger 31a Cylindrical part 31b Flange part 31c Minute protrusion 32 Magnetic rubber part 50 Sensor

Claims (2)

An annular member having a cylindrical portion attached to the shaft and a flange portion extending from the end of the cylindrical portion toward the outer diameter side;
A magnetic rubber portion that is baked and fixed by molding on the surface of the flange portion opposite to the cylindrical portion after the annular member is coated with an adhesive;
A magnetic encoder that is detected with respect to rotation of a shaft based on a change in a position of the surface of the magnetic rubber portion by a sensor disposed on a side where the magnetic rubber portion is fixed with respect to the flange portion ;
Magnetic encoder and providing a microprojection before Symbol Table surface in the flange portion. The surface on the cylindrical portion side of the flange portion is used as a seal surface on which a seal lip of a sealing device is slidably contacted,
The magnetic encoder according to claim 1, wherein the minute protrusions are protrusions that are continuously provided over the entire circumference of the tip of the flange portion.

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