Electromagnetic valve
An oil control valve has a cup shaft and a plunger. The cup shaft and the plunger have a projection and a recess to provide a male-female joint. The male-female joint provides contact points which can reduce lateral offset and inclination. The projection and the recess provides two or more force transmitting points from the plunger to the cup shaft, when the projection and the recess are inclined with each other. The force transmitting points are located about the central axis of the spool in a distributed manner.
1. An electromagnetic valve comprising:
a spool valve having a sleeve formed in a cylindrical shape extending along a central axis from a base end to a distal end, and a spool supported within a spool bore formed in the sleeve in a reciprocally movable manner;
a shaft disposed axially next to the spool in contact with the base end of the spool in a manner that the shaft is capable of inclining relative to the spool; and
an electromagnetic actuator having a stator core formed in a cylindrical shape and fixed on the base end of the sleeve, a cup guide formed in a bottomed cylindrical shape and disposed radial inside of the stator core, a movable core supported in a guide bore formed within the cup guide in a reciprocally movable manner and connected to the spool via the shaft in an integrally movable manner, and a coil excited by current to magnetize the movable core and the stator core, wherein
the shaft has a first stepped portion formed in a shape to provide a male-female joint, the first stepped portion being formed on a first end portion, which comes in contact with the movable core,
the movable core has a second stepped portion formed in a shape to provide the male-female joint with the first stepped portion, the second stepped portion being formed on a second end portion, which comes in contact with the shaft,
the male-female joint is a loose joint which defines a small clearance between the first stepped portion and the second stepped portion,
the loose joint with the small clearance is configured to engage in a slanting manner, and
inclination of the shaft relative to the spool transmits axial movement of the movable core to the spool by the male-female joint.
2. The electromagnetic valve claimed in claim 1 , wherein
one of the first stepped portion or the second stepped portion has a projection, and wherein
the other one of the first stepped portion or the second stepped portion has a recess, which provides a male-female joint with the projection.
3. The electromagnetic valve claimed in claim 2 , wherein
the first stepped portion has a first axial end surface, which is formed in a ring shape, and a projection, which is projected from a radial inside of the first axial end surface in one direction along the central axis, and wherein
the second stepped portion has a second axial end surface, which is formed in a ring shape and comes in contact with the first axial end surface, and a recess, which extends from a radial inside of the second axial end surface in the same direction as the projecting direction of the projection and provides the male-female joint with the projection.
4. The electromagnetic valve claimed in claim 2 , wherein
the first stepped portion has a first axial end surface, which is formed in a ring shape, and a recess, which extends from a radial inside of the first axial end surface in one direction along the central axis, and wherein
the second stepped portion has a second axial end surface, which is formed in a ring shape and comes in contact with the first axial end surface, and a projection, which is projected from a radial inside of the second axial end surface in the same direction as the extending direction of the recess and provides the male-female joint with the recess.
5. The electromagnetic valve claimed in claim 2 , wherein
the projection and the recess provides two or more force transmitting points from the movable core to the shaft, when the projection and the recess are inclined with each other, the force transmitting points being located about the central axis of the spool.
6. The electromagnetic valve claimed in claim 5 , wherein
the projection is formed to have a tapered profile defining gradually decreasing outer diameter from a base to a distal end of the projection.
7. The electromagnetic valve claimed in claim 2 , wherein
the projection is formed to have a curved profile.
8. The electromagnetic valve claimed in claim 2 , wherein
the small clearance is also between the projection and the recess.
9. The electromagnetic valve claimed in claim 1 , wherein
the shaft is formed in a cup shape which opens on at least one end in an axial direction and defines a hollow portion therein.
10. The electromagnetic valve claimed in claim 9 , wherein
the spool has a spool axial bore which penetrates the center of the spool along the central axis, and wherein
the hollow portion has an opening which communicates with the axial bore, and wherein
the opening is formed on a side where the shaft opens.
11. The electromagnetic valve claimed in claim 9 , wherein
the movable core has a core axial bore which penetrates the center of the movable core along the central axis, and wherein
the hollow portion has a communicating aperture which communicates with the core axial bore, and wherein
the communicating aperture is formed on a side where the shaft has a bottom.
12. The electromagnetic valve claimed in claim 9 , wherein
the shaft has a cylindrical side wall extending along the central axis,
the cylindrical side wall defining a communicating aperture which penetrates the cylindrical side wall in a radial direction and communicates a radial inside of the shaft and a radial outside of the shaft.
13. The electromagnetic valve claimed in claim 1 , wherein
the electromagnetic actuator has a magnetically opposing portion disposed to axially oppose the movable core to attract the movable core toward the spool valve.