JP3484474B2 - Sticker with tone wheel - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing material formed with a rotation speed detecting device for detecting the rotation speed of an automobile wheel or the like, and a tone having improved rotation detection accuracy and good moldability. Regarding seals with wheels.

[0002]

2. Description of the Related Art A tone wheel is equipped to freely control a traveling safety device such as an anti-lock brake system, a traction control system, or a stability control system that can be installed in an automobile. It is installed on the hub flange of the suspension system of an automobile to detect the rotation speed of its wheels, and it detects the difference in the rotation speed of multiple wheels such as front and rear, left and right, and turns on the drive device or brake device.
It is turned off to control the behavior of the vehicle in an emergency to ensure stability and safety.

On the other hand, a seal for preventing the leakage of lubricating oil is indispensable in the rotating portion where the traveling safety device as described above is mounted, and the rotation speed detecting device and the sealing material are provided in the gap of the rotating portion. The mounted structure is generally used. In recent years, a sealing ring with a rotation detecting device in which such a rotation speed detecting device and a sealing material are united has become popular. As a seal with a rotation speed detecting device of the general structure, that is, a seal with a tone wheel, as shown in FIG. 4 when explained by the drawing, as shown in FIG. In many cases, the ring portion (3b) is formed and the tone wheel is formed by magnetizing the ring portion (3b). The rotation speed detection sensor (4) is brought close to the ring portion (3b). It is installed and detects the rotation speed of the wheel.

[0004]

However, in the tone wheel including the radial annular portion (3b) formed on the flange of the sealing material (3a), the running stability is intended. Therefore, a large area and a smooth pulse generating surface (31b) are required because the accuracy of the rotation speed detection is required, but in reality, injection molding injection holes for material filling (Fig. In many cases, (not shown) is arranged on the pulse generating surface (31b), and when the injection hole is installed on the pulse generating surface (31b), flow wave scratches or burrs are generated in the vicinity thereof. However, even if the portion is carefully finished and formed, the smoothness of the flat surface is lost, so that the magnetic force of the subsequent magnetization is adversely affected to a considerable extent, and a highly accurate magnetic pole cannot be formed.

Further, a magnetic elastic material and a sealing material (3a) are put into a mold which has been conventionally used, and an annular portion (3
In the compression molding method (not shown) in which b) is formed by compression, it is difficult to evenly distribute the magnetic material in the pressed elastic material on the circumference without maintaining uniformity in the compression flow direction. However, this also cannot form a uniform magnetic pole.

In view of such drawbacks, the present invention has an object to provide a seal with a tone wheel capable of accurately magnetizing a magnetic pole portion having a large area and realizing highly accurate rotation speed detection. .

[0007]

According to the present invention, a closed ring (2a) is press-fitted and supported on inner and outer diameter sides (not shown) of a bearing unit (1) which is a housing, and the closed ring (2).
A seal with a tone wheel provided with an elastic magnet (2b) of a multi-pole magnet in which S poles and N poles are circumferentially arranged in a radial direction of a), and the elastic magnet (2b ) Is a composite material in which a powder of a ferromagnetic material such as ferrite is mixed and formed in an elastic material such as synthetic rubber or synthetic resin, and is provided on the back surface evenly distributed to the outer periphery of the radial portion of the closed ring (2a). A plurality of cutouts (2c) communicating with each other is formed, and the composite material is evenly distributed from the back surface side of the closed ring (2a) using the plurality of cutouts (2c) as an inflow passage .
It is characterized in that the elastic magnet (2b) is formed by injection filling.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the present invention resides in a magnetic type tone wheel and a rotation speed detecting sensor (4) for detecting the rotation speed of a magnetic pole by rotating the magnetic pole surface for generating a pulse. double from the rear side of the closure ring (2a) and (21)
Through which cutout portions arranged in several equally (2c)
The elastic yoke (2b) is pressed by a magnetizing yoke (not shown) on the magnetic pole surface (21) of the formed elastic magnet (2b) to form the elastic magnet (2b). The S pole and N pole are alternately carved at equal intervals, and the magnetic poles are accurately transferred as they are to be magnetized.
Here, a clear and strong magnetic pole can be obtained, and the sensing ability of the rotation speed detection sensor (4) can be remarkably enhanced to enable highly accurate rotation speed detection.

[0009]

EXAMPLE The present invention is made in such a manner that the magnetic material of the elastic magnet (2b) is evenly distributed in a circumferential shape and is molded. In this embodiment, the composite material containing the magnetic material is contained in the cavity of the mold. Using the injection molding method of injecting or the transfer molding method of injecting the composite material from the pot,
As shown in FIG. 1 and FIG. 3, an injection hole (2d) for material filling is arranged in the mold cavity on the back side of the closed ring (2a) to be injected, and the injection hole (2d) is inserted from the injection hole (2d) as shown in FIG. Material is injected through the notch (2c) and the composite material is filled from the back surface side to form the elastic magnet (2b). The notch holes (2c) are evenly distributed and formed in the radial direction of the closed ring (2a), and the composite material injected from the injection hole (2d) for injection or injection molding has the notch part (2c). 2c) flows toward the magnetic pole surface (21) in a uniform amount while maintaining a correct distribution position, is filled, and fills the cavity. Here magnetic pole surface (21)
In addition to obtaining a smooth molding surface, it is possible to obtain a magnetic material that is evenly aligned and arranged. Therefore, the accuracy of magnetization is improved and a clear pulse generating magnetic pole is formed.

The notch (2c) shown in FIG. 2 has a shape in which the outer peripheral edge of the radial direction of the closed ring (2a) is notched, which is easy to form and has excellent filling flowability of the composite material. ,
It is also possible to form in the shape of a plurality of through holes leading to the back surface as shown in Fig. 1. With this shape, the injection amount can be controlled more, so that the accuracy of injecting the composite material is increased and the entire outer edge is increased. The rigidity of the circumference can be kept strong.

In magnetizing, a magnetizing yoke in which S poles and N poles are alternately arranged is used as a magnetic pole surface (2) of an elastic magnet (2b).
When pressed into contact with 1), the elastic magnet (2b) made of an elastic material such as synthetic rubber or synthetic resin adheres evenly and securely to the entire circumferential surface while being elastically deformed. The engraved magnetic poles can be accurately transferred and magnetized.

[0012]

With the above-described structure, the following excellent effects can be obtained. The tone wheel seal of the present invention uses an injection or injection molding type molding method which is excellent in productivity and can be formed by directly injecting the molding material into the mold cavity. Even if there is, it is arranged evenly from the back side of the pulse generation surface.
By injecting and forming through a plurality of notches (2c), a smooth surface can be obtained, and the magnetic material in the elastic material can be evenly distributed on the circumference, and thus accurate magnetization can be achieved with high accuracy. It became possible to realize the rotation speed detection.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an embodiment of the present invention.

FIG. 2 is a plan view showing another embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view showing another embodiment of the present invention.

FIG. 4 is a sectional view showing a mounting example not using the present invention.

[Explanation of symbols]

1 Bearing unit 2a closed ring 2b Elastic magnet 2c Notch 2d injection hole 21 Magnetic pole face 3a Sealant 3b ring part 31b Pulse generation surface 4 Rotation speed detection sensor

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01P 3/487 F16C 33/78 F16J 15/32 311

Claims (2)

(57) [Claims] 1. A closed ring which is press-fitted and supported on an inner diameter side or an outer diameter side of a housing, and an elastic magnet of a multi-pole magnet in which an S pole and an N pole are circumferentially arranged in a radial direction of the closed ring. In the seal with a tone wheel, the elastic magnet is composed of a composite material in which a powder of a ferromagnetic material is mixed and formed in an elastic material, and a plurality of the plurality of leading to the back surface evenly distributed in the radial direction of the closed ring are provided . A seal with a tone wheel, characterized in that a notch is formed and an elastic magnet is formed by injecting and filling an equal amount of the composite material from the back side of the closed ring using the notch as an inflow passage. 2. The seal with a tone wheel according to claim 1, wherein the notch formed in the radial portion of the closed ring and communicating with the back surface is a plurality of through holes.