JP2008268016A - Wheel speed sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent damages due to collision, adhesion, movement of solid, such as, iron powder of the resin covering of a wheel speed sensor P exposed by the resin covering 4 of a detection part (a). <P>SOLUTION: The wheel speed sensor P outputs to be converted into electrical signals, by detecting a magnetic variable due to rotation of a sensor rotor 2 with a Hall IC11. The detection part a is performed by only the resin covering 4 (exposed to the outside by the resin covering 4), and a metal cover 30 is fitted to be fixed on a resin covering part around the detection part a. The cover is also attached to an existing wheel speed sensor P. On the resin covering face on which a solid, such as iron powder collides, adheres and moves due to the rotation of the sensor rotor, a face (detection part portion) opposed to the sensor rotor is the main face, the face is covered with the metal cover, and the cover has very small damages due to collision or the like of the solid. Thus, damages to the resin covering around the detection part (magneto-electric convertor 11) of the inside is very small, and there is no risk-generating malfunctions of the detection part a due to the damages of the resin covering 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle wheel speed sensor.

For example, in order to equip an automobile with an ABS (anti-lock braking system), it is necessary to measure the wheel speed of the automobile. For the measurement, a wheel speed sensor is used, and as shown in FIG. 14, a sensor rotor 2 is concentrically mounted on the wheel hub 1, and a wheel speed sensor P is mounted on the hub cap 3 so as to face the sensor rotor 2. Mounting, the wheel speed sensor P detects a magnetic flux variation caused by the rotation of the sensor rotor 2, converts it into an electrical signal, and outputs it to an ABS control device via a cable 6 (see FIG. 1 of Patent Document 1). .
JP 2006-170207 A

The wheel speed sensor P has a detection unit a that detects a magnetic field variable due to the rotation of the sensor rotor 2 and converts it into an electrical signal and outputs it, and the lead terminal is derived from the magnetoelectric transducer. Attached (provided) to a plastic holder (bobbin), inserts the holder into the covered cylindrical casing from its opening, mounts the detection part a, and connects a pair of relay terminals to the lead piece from the detection part a Further, the relay terminal is led out from the end surface of the holder base and connected to the cable 6, and the relay terminal and a part of the cable 6 are embedded over the entire circumference of the casing opening and the holder exposed portion to cover the resin. (See Patent Document 2, FIG. 1, FIG. 2, etc.).
JP 2006-30075 A

As another example of the wheel speed sensor P, the output cable 6 can be directly applied to the lead piece without mounting the detection part a on the casing and directly coating the detection part a with a resin 4 or without a relay terminal. May be connected (see, for example, FIG. 1 of Patent Document 3).
JP 2005-227095 A

  As can be understood from FIG. 14, the wheel speed sensor P is provided to face the sensor rotor 2, so that various fine solids due to the rotation of the sensor rotor 2 collide and adhere to each other. In particular, when the sensor rotor 2 is a magnet encoder in which magnets are arranged, the iron powder or the like collides and adheres. The attached solid matter moves as the sensor rotor 2 rotates.

The wheel speed sensor P in which the detection unit a is mounted in the casing has a metallic casing. Therefore, even if the solid matter such as the iron powder collides and moves on the casing surface, the casing is scraped and has a hole. Since there was no scratch, the collision and adhesion movement of the solid matter was not considered a problem.
Further, even in the wheel speed sensor P in which the detection portion a is directly resin-coated 4 without being mounted on the casing, the resin coating 4 is exposed to the outside, but conventionally the layer thickness of the resin coating 4 has been sufficiently thick. Similarly, damage to the resin coating 4 due to collision and adhesion movement of the solid matter such as the iron powder has not been a problem.

However, when the wheel speed sensor P is required to be reduced in size and the wheel speed sensor P where the resin coating 4 of the detection part a is exposed, the layer thickness of the resin coating 4 needs to be reduced.
In this case, since the resin coating 4 has a sufficient layer thickness as in the prior art, the idea that damage due to scraping of the resin coating 4 due to the collision and adhesion movement is okay is not valid. When the thin resin coating 4 is scraped and further thinned due to collision, adhesion, and movement of a solid material such as iron powder, the hermeticity of the detection unit a (magnetoelectric transducer) decreases, and the required physical durability If the resin coating 4 is scraped and the magnetoelectric transducer is exposed, the magnetoelectric transducer is damaged.

  This invention makes it a subject to prevent the damage by the collision and adhesion | attachment / movement of solid substances, such as the said iron powder, of the resin coating of the wheel speed sensor P where the resin coating 4 of such a detection part a is exposed.

In order to achieve the above object, the present invention is directed to the sensor rotor 2 of the resin coating 4 covering the periphery of the magnetoelectric transducer of the detection unit a in the wheel speed sensor P where the resin coating 4 of the detection unit a is exposed. A metal cover was provided on the surface to be used.
As described above, the wheel speed sensor P from which the resin coating 4 of the detection unit a is exposed is advantageous in downsizing, and the layer thickness of the resin coating 4 is reduced when further downsizing is attempted. In such a wheel speed sensor, the resin-coated surface that collides with, adheres to, and moves with the solid matter such as iron powder is mainly the surface facing the sensor rotor, and the metal cover provided on the surface is the same as the casing described above. Similarly, damage due to collision, adhesion, and movement of solid materials such as iron powder is extremely small. For this reason, there is no damage to the resin coating around the inner detection section (magnetoelectric transducer), and there is no possibility of the malfunction of the detection section due to the damage of the resin coating.

  As a configuration of the present invention, a detection unit in which a lead terminal is derived from a magnetoelectric transducer that detects a magnetic field variable due to rotation of a sensor rotor attached to a wheel hub, converts it to an electric signal, and outputs it, and the detection unit are attached. A magneto-electric transducer of the detection unit, comprising: a holder connected to the lead terminal; a cable that transmits the electrical signal to the outside; and a resin coating that covers the detection unit and a part of the cable and is exposed to the outside. In the wheel speed sensor exposed to the outside, the resin coating that covers the periphery can employ a configuration in which a metal cover is provided on the surface of the detection section that faces the sensor rotor of the resin coating that covers the periphery of the magnetoelectric transducer. .

  The area (size) and position of the metal cover covering the coating resin is appropriately set by an experiment or the like so that the magnetoelectric transducer is not damaged. Also, the material of the metal cover is preferably a non-magnetic material, but if it is a magnetic material, it is firmly fixed to the resin coating so that it does not move relative to the resin coating by vibrations or the like. When the magnetic metal cover moves, the magnetic field fluctuates, the magnetic field due to the rotation of the sensor rotor fluctuates, and the variable does not accurately correspond to the rotation of the sensor rotor, and the accuracy of the rotation detection value of the sensor rotor decreases. This is because the detection accuracy of the wheel speed sensor is reduced.

  Various attachment modes (attachment means) to the resin cover of the metal cover can be considered, such as when the resin cover is formed (when the detection part is resin-molded), by embedding part of the metal cover, etc. It is preferable to fit and fix the resin coating around the magnetoelectric transducer. This is because the metal cover can be attached not only after the resin coating is formed, that is, after the wheel speed sensor is manufactured, but also to the existing wheel speed sensor in the vehicle.

For this reason, in order to prevent damage to the detection part of the existing wheel speed sensor in the vehicle, a metal cover covering the surface facing the sensor rotor is fitted to the resin coating covering the periphery of the magnetoelectric transducer of the detection part. To do.
That is, a detection unit for deriving a lead terminal from a magnetoelectric transducer that detects a magnetic field variable due to rotation of a sensor rotor attached to a wheel hub, converts it to an electrical signal, and outputs, a holder to which the detection unit is attached, The cable is connected to the lead terminal and transmits the electrical signal to the outside, and the resin coating that covers the detection unit and a part of the cable. The resin coating that covers the detection unit is exposed to the vehicle. In the existing wheel speed sensor, a metal cover covering the surface facing the sensor rotor is fitted to the resin coating covering the periphery of the magnetoelectric transducer of the detection unit, and the metal cover prevents damage to the detection unit. Do.

  The metal cover is fitted and fixed by forming a protrusion on one side of the resin cover around the metal cover and the magnetoelectric transducer, and a hole for locking the protrusion on the other, and locking the protrusion to the hole. Or a metal cover formed with a locking hole, a resin coating around the magnetoelectric transducer is formed with a protrusion that fits into the locking hole, and the protrusion is fitted into the locking hole and swaged to prevent it from coming off. can do.

  The present invention is configured as described above, and the damage of the wheel speed sensor that can be reduced in size by exposing the resin coating of the detection portion is effectively prevented by collision and adhesion / movement of solid matter such as iron powder of the resin coating. Therefore, a decrease in detection accuracy due to damage to the resin coating can be eliminated.

  An embodiment is shown in FIGS. 1 to 4, and the wheel speed sensor P of this embodiment uses a linear lead parallel to a detection section a from a Hall IC 11 having a Hall element (magnetoelectric conversion element) that detects a magnetic field variation. A piece (lead terminal) 12 is led out, and an electronic component 13 such as a capacitor is provided between the lead pieces 12 and 12. Flexible core wires (conductors) 6a, 6a of a pair of insulated wires of the output cable 6 are connected to the pair of lead pieces 12, 12 by soldering or the like (see FIGS. 3 to 4).

As shown in FIGS. 3 and 4, the resin molded product holder 20 has a fitting recess 14 for the Hall IC 11 formed in the front part of one surface of the rectangular parallelepiped. An insertion hole 15 for the lead piece 12 is formed in the rear wall of the holder 20 (see FIG. 3). By inserting the lead piece 12 into the insertion hole 15 and fitting the hole IC 11 into the recess 14. The detection unit a is reliably positioned and set (held) on the holder 20.
In the figure, reference numeral 8 denotes a locking tool (cover) that is fitted to the holder 20 after the detection portion a is set in the holder 20. When the locking tool 8 is fitted to the holder 20, the detection portion a is moved to the holder 20. Is held securely.

The holder 20 is provided with a partition wall 21 which is located between both connecting portions of the lead piece 12 and the flexible core wire 6a of the output cable 6 and prevents the contact between the core wires 6a and 6a. (See FIG. 4). The core wires 6a and 6a of the output cable 6 are set on the lead pieces 12 and 12 so as to sandwich the partition wall 21 and connected by soldering.
Thereafter, the resin coating 4 for embedding a part of the Hall IC 11, the lead piece 12, the entire holder 20, the output cable 6 and the mounting bracket 10 is injection-molded. The mounting bracket 10 can also be comprised by the resin coating 4 (refer patent document 2 FIG. 1).

  A cover 30 made of SUS304CSP (spring material) is fitted and fixed to the outer peripheral surface of the resin coating 4 around the detection part a. The cover 30 has a cylindrical shape with a lid, and is fitted from the front side (detection part a) of the resin coating 4 as shown in FIG. 2A to FIG. Fix it immobile. An adhesive can be interposed between the outer surface of the resin coating 4 and the inner surface of the cover 30. By attaching the cover 30, the wheel speed sensor P according to this embodiment is obtained. SUS304L or the like can be used in addition to SUS304CSP.

  The wheel speed sensor P is attached to the hub cap 3 so as to face the sensor rotor 2 as shown in FIG. Since this wheel speed sensor P does not have a magnet, the sensor rotor 2 uses a magnet encoder magnetized so that the S pole and the N pole are alternately continued in the circumferential direction on the outer peripheral edge thereof.

FIGS. 5 to 9 show other embodiments of the metal cover 30, and the metal cover 30 of the embodiment of FIG. 5 is provided with projecting pieces 32 having locking holes 31 at both ends of the covered rectangular cylindrical body. A protrusion 41 is provided on the resin coating 4 side to be locked (fitted) in the locking hole 31. The metal cover 30 is fitted into the resin coating 4 as shown in FIGS. 1A to 1B, and the metal cover 30 is firmly attached to the resin coating 4 by the locking of the locking holes 31 and the protrusions 41. Fixed.
The metal cover 30 of the embodiment of FIG. 6 is formed by slitting the required ridgeline of the covered rectangular cylindrical body to cut each surface, and similarly, forming a locking hole 31 on an appropriate piece thereof. On the side of the coating 4, a protrusion 41 that is locked in the locking hole 31 is provided. The metal cover 30 is also fitted into the resin coating 4 as shown in FIGS. 4A to 4C, and is firmly fixed to the resin coating 4 by the locking of the locking holes 31 and the protrusions 41. The 2A is a top view and FIG. 2B is a bottom view.

As described above, the metal cover 30 fitted and fixed to the resin coating 4 by the locking of the locking holes 31 and the protrusions 41 has no bottom piece as shown in FIG. 7, or has a claw 33 as shown in FIG. Or the like. That is, the embodiment is arbitrary as long as the effects of the present invention are exhibited.
Further, in each of these embodiments, the locking holes 31 and the protrusions 41 can be provided with the former 31 on the resin coating 4 side and the latter 41 on the cover 30 side.

  In the embodiment shown in FIG. 9, the protrusion 41 is caulked as indicated by an arrow shown in FIG. 9B to increase the locking force between the protrusion 41 and the locking hole 31. The position, number and shape of the crimping protrusion 41 and the non-crimping protrusion 41, and the position, number and shape of the locking hole 31 to which the protrusion 41 is locked are appropriately determined by experimentation in consideration of manufacturability, fixing strength and the like. Set. For example, as shown in FIG. 5A, the locking hole 31 may be opened at the side edge of the metal piece (cover 30). Various forms such as those shown in FIGS. 5 to 8 can also be adopted for the outer shape of the metal cover 30.

The aspect of the detection unit a is not limited to that described above, and various types are conceivable. For example, the wheel speed sensor P of the detection unit a shown in FIGS.
That is, as shown in FIG. 12, the holder 20 of the resin molded product of this embodiment includes a base portion 20a and a lid portion 20b that form a main body, and a fitting groove (concave portion) 14 for the Hall IC 11 is formed in the base portion 20a. Has been. The lid portion 20b is attached (integrated) to the base portion 20a by fitting the hook 22a of the base portion 20a into the hole 22b of the lid portion 20b.
When the detection part a is mounted on the base part 20a, the partition wall 22 is located between the pair of lead pieces 12 and 12 from the Hall IC 11, and the pair of flexible conductors 6a of the output cable 6 are connected to both the lead pieces 12 and 12. 6a are soldered (see FIG. 13).

  If the output cable 6 is connected to the lead pieces 12 and 12 of the detection unit a set in the holder 20, as shown in FIG. 10, the mounting bracket 10 is embedded and the holder 20, the detection unit a and the output cable 6 are connected. Part 4 is coated with resin. The metal cover 30 is fitted and fixed to the resin coating 4 to obtain a wheel speed sensor P (see FIG. 11).

In each of the above embodiments, the metal cover 30 is attached by being fitted to the resin coating 4 and locked. However, when the resin coating 4 is formed (when the detection portion a is resin-molded), a part of the metal cover 30 is inserted. The metal cover 30 can be attached and fixed to the resin coating 4 by various means such as by embedding.
In order to fit and attach the metal cover 30 to the existing wheel speed sensor P in the vehicle, there are many cases where there is no appropriate protrusion or locking hole on the resin coating 4 side. It is good to get an effect. A locking hole can be newly formed on the coating resin 4 side.

  As described above, since various forms such as the shape of the metal cover 30, its mounting and fixing, and the detection part a can be considered, the embodiment disclosed this time is illustrative and restrictive in all respects. It should be considered not. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

Cut front view of one embodiment Attached view of the metal cover of the same embodiment Exploded perspective view of the detector Perspective view of the detector Attachment example of another example of the metal cover of the same embodiment Attachment example of another example of the metal cover of the same embodiment Attachment example of another example of the metal cover of the same embodiment Attachment example of another example of the metal cover of the same embodiment Attachment example of another example of the metal cover of the same embodiment Cut front view of another embodiment Attached view of the metal cover of the same embodiment Exploded perspective view of the detector Perspective view of the detector Wheel speed sensor installation diagram

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wheel hub 2 Sensor rotor 3 Hub cap 4 Resin coating 6 Cable 11 Hall IC (magnetoelectric transducer)
12 Lead piece (Lead terminal)
20 Holder 30 Metal cover 31 Cover locking hole 41 Resin-coated projection P Wheel speed sensor a Detector

Claims (5)

A detection unit (a) in which a lead terminal (12) is derived from a magnetoelectric transducer (11) that detects a magnetic field variable due to rotation of a sensor rotor (2) attached to a wheel hub (1), converts it into an electrical signal, and outputs it. A holder (20) to which the detection unit (a) is attached, a cable (6) connected to the lead terminal (12) to transmit the electrical signal to the outside, the detection unit (a) and the cable The resin coating (4) covering a part of (6), and the resin coating (4) covering the periphery of the magnetoelectric transducer (11) of the detection part (a) is a wheel speed sensor (P ) And
A wheel speed sensor characterized in that a metal cover (30) is provided on a surface facing the sensor rotor (2) of the resin coating (4) covering the periphery of the magnetoelectric transducer (11) of the detection unit (a). .   The wheel speed sensor according to claim 1, wherein the metal cover (30) is fitted and fixed to a resin coating (4) around the magnetoelectric transducer (11).   A protrusion (41) is formed on one side of the resin cover (4) around the metal cover (30) and the magnetoelectric transducer (11), and a hole (31) for locking the protrusion (41) is formed on the other side. The wheel speed sensor according to claim 1 or 2, wherein the metal cover (30) is fixed to the resin coating (4) by locking the protrusion (41) to the hole (31). .   A locking hole (31) is formed in the metal cover (30), and a protrusion (41) that fits into the locking hole (31) is formed in the resin coating (4) around the magnetoelectric transducer (11). The wheel speed sensor according to claim 1, wherein the protrusion (41) is fitted into the locking hole (31) and is caulked to prevent it from coming off. A detection unit (a) in which a lead terminal (12) is derived from a magnetoelectric transducer (11) that detects a magnetic field variable due to rotation of a sensor rotor (2) attached to a wheel hub (1), converts it into an electrical signal, and outputs it. A holder (20) to which the detection unit (a) is attached, a cable (6) connected to the lead terminal (12) to transmit the electrical signal to the outside, the detection unit (a) and the cable A resin coating (4) that covers a part of (6), and the resin coating (4) that covers the periphery of the magnetoelectric transducer (11) of the detection unit (a) is an existing wheel on the vehicle exposed to the outside. A method for preventing damage to the detection portion (a) of the speed sensor (P),
A metal cover (30) covering the surface facing the sensor rotor (2) is fitted into a resin coating (4) covering the periphery of the magnetoelectric transducer (11) of the detection unit (a), and the metal cover ( 30) The method for preventing damage to the detection unit of the existing wheel speed sensor, wherein the detection unit (a) is prevented from being damaged by 30).

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