Linear solenoid with abutted portion

Abstract

A linear solenoid is disclosed that includes a coil that generates magnetic force due to transmission of current therethrough. The linear solenoid also includes a plunger with an end face, a stator that movably supports the plunger, and a yoke including a bottom face. Furthermore, a biasing member is included that biases the plunger in a first direction along the axis. The stator magnetically attracts the plunger when current is transmitted through the coil so as to move the plunger in a second direction along the axis opposite to the first direction. Also, when current transmission through the coil is stopped, the biasing member biases the plunger to abut the bottom face of the yoke at least one abutted portion. Also a non-contact portion is included between the abutted portions where the plunger and the stator are spaced away from each other in the direction of the axis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an axial sectional view of an electromagnetic valve of the prior art;

FIG. 1B is an axial sectional view of an electromagnetic valve constructed according to the present disclosure;

FIG. 2A is a longitudinal sectional view of the valve;

FIGS. 2B and 2C are graphs illustrating jumping in hydraulic characteristics;

FIG. 3 is a longitudinal sectional view of an electromagnetic hydraulic control valve constructed according to the present disclosure;

FIG. 4 is an axial sectional view of the electromagnetic valve constructed according to the present disclosure in another embodiment;

FIG. 5 is an axial sectional view of the electromagnetic valve constructed according to the present disclosure in another embodiment;

FIG. 6A is a longitudinal sectional view of the electromagnetic valve constructed according to the present disclosure in another embodiment;

FIG. 6B is an axial sectional view of the electromagnetic valve of FIG. 6A; and

FIG. 6C is an axial sectional view of another embodiment of the electromagnetic valve.

Claims

1. A linear solenoid with an axis comprising: a coil that generates magnetic force due to transmission of current therethrough;a plunger with an end face;a stator that movably supports the plunger;a yoke including a bottom face; anda biasing member that biases the plunger in a first direction along the axis;wherein the stator magnetically attracts the plunger when current is transmitted through the coil so as to move the plunger in a second direction along the axis opposite to the first direction;wherein, when current transmission through the coil is stopped, the biasing member biases the plunger to abut the bottom face of the yoke at a plurality of abutted portions; andwherein a non-contact portion is included between the abutted portions where the plunger and the stator are spaced away from each other in the direction of the axis.

2. The linear solenoid according to claim 1, wherein the abutted portions are spaced way from each other circumferentially about the axis at substantially equal intervals.

3. The linear solenoid according to claim 1, wherein the abutted portions have approximately equal areas.

4. The linear solenoid according to claim 1, wherein the bottom face of the yoke includes a recessed portion so as to define the non-contact portions.

5. The linear solenoid according to claim 4, wherein the recessed portion extends radially away from the axis beyond an edge of the plunger as viewed along the axis.

6. The linear solenoid according to claim 1, wherein the linear solenoid is employed in combination with a spool valve having a spool that is moved by the plunger and a sleeve that movably supports the spool.

7. The linear solenoid according to claim 6, wherein the spool valve is a hydraulic control valve that controls oil pressure.

8. A linear solenoid with an axis comprising: a coil that generates magnetic force due to transmission of current therethrough;a plunger with an end face and an edge;a stator that movably supports the plunger;a yoke including a bottom face; anda biasing member that biases the plunger in a first direction along the axis;wherein the stator magnetically attracts the plunger when current is transmitted through the coil so as to move the plunger in a second direction along the axis opposite to the first direction;wherein, when current transmission through the coil is stopped, the biasing member biases the plunger to abut the bottom face of the yoke at an abutted portion;wherein the abutted portion is provided within the edge of the plunger when viewed along the axis; andwherein a non-contact portion is included where the plunger and the stator are spaced away from each other in the direction of the axis.

9. The linear solenoid according to claim 8, wherein an axial center of the abutted portion is aligned with an axial center of the plunger.

10. The linear solenoid according to claim 8, wherein the plunger abuts the yoke at a plurality of abutted portions

11. The linear solenoid according to claim 10, wherein the abutted portions are spaced way from each other circumferentially about the axis at substantially equal intervals.

12. The linear solenoid according to claim 10, wherein the abutted portions have approximately the same area.

13. The linear solenoid according to claim 8, wherein the bottom face of the yoke includes a recessed portion so as to define the non-contact portion.

14. The linear solenoid according to claim 13, wherein the recessed portion extends radially away from the axis beyond the edge of the plunger as viewed along the axis.

15. The linear solenoid according to claim 8, wherein the bottom face of the yoke includes a projected portion that extends toward the plunger.

16. The linear solenoid according to claim 8, wherein the linear solenoid is employed in combination with a spool valve having a spool that is moved by the plunger and a sleeve that movably supports the spool.

17. The linear solenoid according to claim 16, wherein the spool valve is a hydraulic control valve that controls oil pressure.