JPH0514923U - Wheel speed sensor pulse rotor - Google Patents

Abstract

(57) [Summary] [Object] The present invention is to provide a pulse rotor of a wheel speed sensor capable of both cost reduction and damage prevention. [Configuration] Here, the ring-shaped main body 20 and the main body 20
A magnetic field generator 2 composed of a large number of magnetic material pieces 22 supported by
1 for detecting a voltage change in the electromagnetic pickup 17 provided opposite to the magnetic generator 21. In particular, a cylindrical base material B composed of a large number of magnetic thin rods 25 and a resin layer P is used.
From the rotor base material R, which is obtained by cutting the same cylindrical base material B, into the main body 20.
And the magnetic field generator 21 is formed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a pulse rotor of a wheel speed sensor capable of outputting wheel speed information by rotating integrally with a wheel, and in particular, a wheel speed sensor comprising a plurality of magnetic material pieces and having a magnetism generating portion opposed to an electromagnetic pickup. Regarding the rotor.

[0002]

[Prior Art]

 When a vehicle is suddenly braked or braked on a slippery road surface, wheel lock is likely to occur. In such a case, the wheel lock causes the vehicle body to slip, so that the stable vehicle body posture and directional stability are likely to be impaired. .. Therefore, the lock tendency of each wheel is detected based on the wheel speed information from the wheel speed sensor, and when the wheel is in the lock tendency, the braking force to the wheel is temporarily reduced and the lock tendency of the wheel is detected. An anti-lock brake control device has been put into practical use in which the braking force is applied again when it disappears. The wheel speed sensor used in such an anti-lock brake device is composed of a pulse rotor that rotates integrally with the wheel concentrically, and an electromagnetic pick-up that is opposed to the annular outer peripheral portion of the rotor.

As shown in FIGS. 5 and 6, the pulse rotor 1 includes a ring-shaped main portion 2 integrally connected to the wheel side and a large number of magnetic tooth pieces 3 extending from the main portion 2 in the centerline direction X. The magnetic field generator 4 is formed. An electromagnetic pickup (not shown) detects a voltage change according to the magnetism that increases or decreases depending on the change in the state of the rotor facing the magnetism generator 4, and detects the vehicle speed information based on the fact that the frequency information of the generated voltage is proportional to the wheel speed information. I can.

[0006] Here, the magnetic generation part 4 composed of a large number of magnetic tooth pieces 3 of the pulse rotor 1 is formed with a concave and convex part in an annular shape, and the same part is usually formed by cutting a ring made of a ferromagnetic material such as iron. Then, a large number of magnetic tooth pieces 3 are formed in an annular shape. Instead of cutting, the main portion 2 and the magnetic field generating portion 4 may be integrally formed of a sintered alloy, or may be manufactured by precision casting.

[0005]

[Problems to be solved by the device]

 By the way, as described above, the uneven magnetic field generating portion 4 is a part having a high manufacturing cost as a result of the entire portion being machined or specially machined. Further, the magnetic generator 4 of such a pulse rotor is composed of a large number of magnetic tooth pieces 3, and if this magnetic tooth piece 3 hits other parts and is damaged, the measurement accuracy will decrease. Has become a problem because it needs to be replaced, and it is placed at the bottom of the vehicle body, and the ferromagnetic material such as iron requires countermeasures against rust. An object of the present invention is to provide a pulse rotor for a wheel speed sensor that can reduce costs.

[0006]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention comprises a ring-shaped main body that rotates concentrically with a wheel, and a plurality of magnetic material pieces that are supported by the main body and are annularly arranged at intervals. It is equipped with a magnetic field generator, and it detects the voltage change according to the magnetic flux change in the electromagnetic pick-up opposite to the magnetic field generator. The main body and the magnetic field generation part are formed by the rotor base material obtained by cutting the same cylindrical base material using a cylindrical base material formed by molding a thin rod of a body into a cylindrical shape with resin. It is characterized by

[0007]

[Action]

 A cylindrical base material is used in which the main body and the magnetic field generator are formed by using a cylindrical base material formed by molding a large number of magnetic thin rods, which are arranged in parallel in an annular shape at a predetermined distance from each other, into a cylindrical shape with resin. It is formed by a rotor base material obtained by cutting into pieces to facilitate the manufacture.

[0008]

【Example】

 FIG. 1 shows a pulse rotor of a wheel speed sensor as an embodiment of the present invention, and the wheel speed sensor is constituted by an electromagnetic pickup 17 provided in opposition to the pulse rotor 10. Here, the front hub 11 is pivotally attached to a knuckle 12 supported by the vehicle body via a suspension (not shown). A brake disc 13 and a wheel (not shown) are integrally tightened and mounted on the outer surface of the front hub 11 by a nut 14 and a hub bolt 15. Further, an annular mounting step portion 16 is formed inside the front hub 11, and the pulse rotor 10 is fitted and adhered to the mounting step portion 16.

The electromagnetic pickup 17 penetrates the back plate 18 and the bracket 19 and faces the pulse rotor 10, and the main part thereof is integrally supported in the mounting hole of the knuckle 12. The electromagnetic pickup 17 is composed of an electrode opposite to the rotor 10, a permanent magnet (not shown) that generates a magnetic field line on the electrode, and a coil (not shown) that changes the generated voltage according to the change of the magnetic flux density in the electrode. A well-known structure is adopted. Here, as shown in FIGS. 2A and 2B, the pulse rotor 10 has a ring shape in which the main body 20 and the magnetic field generator 21 are continuously formed in the rotation center line direction X. Here, the main body 20 and the magnetic field generator 21 are composed of a large number of magnetic material pieces 22 that are long in the rotation center line direction X, a resin gap filling layer 23 filled between the magnetic material pieces 22, and the gap filling layer 23. An annular resin layer 24 made of a resin that annularly covers a large number of magnetic pieces 22. Here, the annular resin layer 24 is integrated with each gap filling layer 23 to achieve the integration of the entire pulse rotor 10.

Here, the gap filling layer 23 and the many magnetic material pieces 22 are provided with a continuous inner peripheral wall, of which the inner diameter D2 of the inner peripheral wall on the side of the main body 20 is larger than the inner diameter D2 of the inner peripheral wall on the side of the magnetic generator 21. It is small in size, so that the main body 20 side is securely fitted to the annular mounting step portion 16 and the relatively wide magnetic generating portion 21 side can be surely arranged to face the electromagnetic pickup 17. The annular mounting step portion 16 adheres and supports the main body 20 with an adhesive, but in some cases, a screw groove may be formed between both joint surfaces, and the both may be screwed together, or they may be integrally joined by press fitting. Is also good. The rotor 10 having such a shape is manufactured by the procedure shown in FIGS.

Here, first, a large number of iron thin rods 25 having a rectangular cross section are prepared, and these are cast into a mold having a cylindrical cavity (not shown). In this case, the thin rods 25 are arranged side by side in a ring shape in parallel with each other in the longitudinal direction of the cavity with a predetermined interval therebetween. Then, a synthetic resin, for example, polypropylene having high heat resistance, is injected into the spaces between the thin rods 25, which are gaps in the cavity, or the annular outer peripheral portion, and molding is performed. As a result, a cylindrical base material B formed by molding a large number of thin rods 25 into a cylindrical shape with resin as shown in FIGS. 3A and 3B is manufactured.

Next, as shown in FIG. 4A, are sequentially manufactured. After that, each rotor base material R is subjected to a cutting work on a main part of its inner wall by a lathe or the like to form a main portion 20 having an inner diameter D1 and a magnetism generating portion 21 having an inner diameter D2 as shown in FIG. 4 (b). It As a result, the cut thin rods 25 on the magnetic generation portion 21 side form the respective magnetic material pieces 22, the resin layers between the cut thin rods 25 form the gap filling layers 23, and the annular outer periphery of the cavity is formed. The ring-shaped resin layer, which is poured into the portion and molded, and then sliced, forms the annular resin layer 24. The main portion 20 of the pulse rotor 10 manufactured in this manner is fitted to the mounting step portion 16 of the front hub 11 on the wheel side, and is integrated by adhesion.

In the pulse rotor 10 integrally coupled to the front hub 11 as described above, the magnetism generating portion 21 thereof is installed opposite to the electromagnetic pickup 17 at a predetermined interval. As a result, the change in magnetic flux density between when the electromagnetic pickup 17 approaches each magnetic piece 22 and when it is in the valley between the pair of magnetic pieces 22 can be sufficiently detected, and the induced electromotive force corresponding to this change can be detected. It is possible to detect the wheel speed information from the frequency change and to accurately perform anti-lock brake control based on this wheel speed information.

[0014]

As described above, according to the present invention, the main body and the magnetism generating portion are formed from the rotor base material obtained by cutting a cylindrical base material formed of a large number of magnetic thin rods and resin into slices. Therefore, the manufacturing is facilitated, suitable for mass production, and the cost can be reduced. Moreover, the manufacturing is facilitated by providing the pulse rotor of the wheel speed sensor having the magnetic field generator, and the cost can be reduced. Since the gaps between the arrayed magnetic material pieces are filled with the resin, the side portions of the magnetic material pieces are less likely to be covered with the resin and damaged, which improves the mounting workability.

[Brief description of drawings]

FIG. 1 is a partial cutaway side sectional view showing a state in which a pulse rotor of a wheel speed sensor according to an embodiment of the present invention is mounted on a front axle of a vehicle.

2A is an overall perspective view of the pulse rotor of FIG. 1, FIG.
(B) is a front view of the same rotor.

3A is a manufacturing process diagram of a cylindrical base material B used for manufacturing the pulse rotor of FIG. 1, and FIG. 3B is a side view of the cylindrical base material B.

4 (a) is an explanatory diagram of a process of cutting a rotor base material R from a cylindrical base material B used for manufacturing the pulse rotor of FIG. 1,
(B) is an explanatory view of a process of manufacturing the pulse rotor of FIG. 1 from the same rotor substrate R.

FIG. 5 is a perspective view of a conventional pulse rotor.

6 is a cross-sectional view of the pulse rotor of FIG.

[Explanation of symbols]

 10 pulse rotor 11 front hub 17 electromagnetic pickup 20 main body 21 magnetic field generator 22 magnetic piece 23 gap filling layer 24 annular resin layer 25 thin rod R rotor base material B cylindrical base material

Claims (1)

[Scope of utility model registration request] 1. A ring-shaped main body which rotates concentrically and integrally with a wheel, and a magnetism generating section which is supported by the main body and is composed of a large number of magnetic material pieces arranged in an annular shape with a space therebetween. In a pulse rotor of a wheel speed sensor for detecting a voltage change according to a magnetic flux change in an electromagnetic pickup opposite to a magnetic generator, a large number of magnetic thin rods arranged in parallel in a ring at a predetermined interval are made of resin. A wheel speed sensor characterized in that a cylindrical base material formed by molding into a cylindrical shape is used, and the main body and the magnetic field generating portion are formed by a rotor base material obtained by cutting the cylindrical base material into slices. Pulse rotor.