SOLENOID AND HYDRAULIC PRESSURE CONTROL APPARATUS HAVING THE SAME

摘要

In a solenoid of a hydraulic pressure control apparatus, a region adjacent to an oil flow guide portion of a stopper breathing passage is formed in a magnetism application region, through which a leakage magnetic flux leaking from a magnetic circuit at a time of turning on of a coil passes. Thereby, magnetic foreign objects made of iron or iron containing material are magnetically attracted to the leakage magnetic flux, so that intrusion of the foreign objects from an outside of the solenoid into a second volume variable chamber through the stopper breathing passage is limited.

主权项

1. A solenoid comprising:
a plunger that is reciprocatable in an axial direction; a stator that includes:
a core, which is opposed to the plunger in the axial direction and is spaced from the plunger by a predetermined distance;a plunger guide that is configured into a tubular form and is placed adjacent to the core, wherein the plunger guide reciprocatably and slidably supports the plunger; anda plunger receiving chamber that is placed on a radially inner side of the plunger guide and reciprocatably and slidably receives the plunger; a coil that generates a magnetic flux, which flows through the plunger and the stator, when the coil is energized; and a stopper that is opposed to the core in the axial direction while the plunger receiving chamber is interposed between the stopper and the core, wherein the stopper limits movement of the plunger toward a side in the axial direction, wherein: a magnetic circuit, which includes the plunger and the stator, is formed to magnetically attract the plunger toward the core when the coil is energized; the plunger receiving chamber includes a volume variable chamber that is formed between the plunger and the stopper; the stopper includes:
a partition wall that partitions between an inside and an outside of the volume variable chamber; anda breathing passage that extends through the partition wall of the stopper and communicates between the inside and the outside of the volume variable chamber; a region adjacent to the breathing passage or at least a portion of the breathing passage is formed in a magnetism application region, wherein a leakage magnetic flux, which is leaked from the magnetic circuit, passes through the magnetism application region.