Rotation detector,wheel bearing equipped therewith and process for manufacturing the same

Abstract

A sensor assembly (3) is sandwiched together with a rubber material (11) mixed with a vulcanizing agent in a mold assembly (2) including an upper mold (9) and a lower mold (10). The upper and lower molds (9, 10), while completely sandwiching the sensor assembly (3), are heated for a predetermined length of time, and a pressure is then applied to the sensor assembly (3) to complete a compressive molding.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit under 35 U.S.C. Section 371, of PCT International Application No. PCT / JP2007 / 001031, filed Sep. 21, 2007, which claimed priorities to Japanese Application Nos. 2006-256827, filed Sep. 22, 2006; Japanese Application No. 2006-262182, filed Sep. 27, 2006; Japanese Application No. 2006-262183, filed Sep. 27, 2006; Japanese Application No. 2006-262184, filed Sep. 27, 2006; Japanese Application No. 2006-262185, filed Sep. 27, 2006; Japanese Application No. 2006-262186, filed Sep. 27, 2006; Japanese Application No. 2006-262187, filed Sep. 27, 2006; Japanese Application No. 2006-281304, filed Oct. 16, 2006; Japanese Application No. 2007-223481, filed Aug. 30, 2007; the disclosures of all of which are hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a rotation detecting device adapted to be employed in association with, for example,...

AI Technical Summary

Benefits of technology

[0015]An object of the present invention is to provide a rotation detecting device, in which the difference in thermal expansion resulting from the self-heating of the sensor component parts and the environmental temperature can be absorbed, which has an excellent water proofing property, in which even when vibrations and / or external forces acts, damage to the sensor component parts can be avoided, allowing it to have an excellent durability, and in which the cost of manufacture can be reduced, and also to provide a wheel support bearing assembly equipped with such rotation detecting device and a method of manufacturing the rotation detecting device.

Problems solved by technology

(1) No adhesion between the covering material and the component parts built therein cannot be expected.

(2) As a result of change in ambient temperature and self-heating of electronic component parts built therein, a gap tends to occur between the covering material and the built-in component parts due to the difference in thermal expansion thereof, thus posing a problem in water proofing property.

(3) Even when an external force acts on the sensor unit molded and a plastic deformation occurs in the covering material, a gap tends to occur between the covering material and the built-in component parts, thus posing a problem in water proofing property.

(4) When an external force acts on the sensor unit molded, such force acts directly on the built-in component parts since the covering material comprised of a resinous material is less susceptible to deformation and, therefore, it will constitute a cause of breakage of the sensor unit.

(5) The covering material comprised of the resinous material lacks a vibration absorbing capability and, therefore, there is a problem in durability relative to external vibrations.

(6) With the molding by means of the conventional injection molding, a nozzle through which a molten resin flows, runners for leading the molten resin towards a cavity portion, which eventually forms a molded product, and inflow gates leading to the cavity portion are required. In order to smoothen the flow of the molten resin to thereby increase the yield, the appropriate number of pieces manufactured at one time is within the range of a few pieces to some tens pieces and thus, the number of pieces molded at one time is limited.

Also, the rotation detecting device such as, for example, the ABS sensor used as fitted to an automobile component part, particularly, the hub bearing assembly, is generally exposed to the road surface and is therefore wetted with a muddy salty water and is also placed under severe environment, in which a temperature change from some tens degree to minus some tens degree occurs.

Yet, since the rotation detecting device is positioned below the suspension system, it is considerably affected by vibrations induced during the travel of the automotive vehicle.

Any erroneous operation of the ABS sensor brings about a considerable influence on the vehicle traveling safety.

Those keen demands cannot be fulfilled with the rotation detecting device formed by the conventional resin molding.

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