Solenoid valve

Abstract

A solenoid valve includes a coil, a stator core, a valve member, a coil spring, and a stopper. The coil provides a magnetic field when the coil is energized. The stator core includes a receiving bore, wherein the stator core generates a magnetic attractive force when the coil is energized. The valve member is attracted toward the stator core due to the magnetic attractive force generated by the stator core. The coil spring is received in the receiving bore of the stator core, wherein the coil spring biases the valve member in an opposite direction opposite from the stator core. The stopper positions the coil spring such that an outer peripheral surface of the coil spring is separated from an inner peripheral surface of the receiving bore.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with additional objectives, features and advantages thereof, will be best understood from the following description, the appended claims and the accompanying drawings in which:

FIG. 1 is a schematic view of a common rail fuel injection system, which includes a solenoid valve according to a first embodiment of the present invention;

FIG. 2 is a sectional view of the solenoid valve shown in FIG. 1;

FIG. 3 is a chart showing an evaluation result of a response time for valve opening of the solenoid valve;

FIG. 4 is a sectional view showing a solenoid valve according to a second embodiment of the present invention;

FIG. 5 is a sectional view showing a main portion of a solenoid valve according to a third embodiment of the present invention; and

FIG. 6 is a sectional view showing a main portion of a solenoid valve according to a fourth embodiment of the present invention.

Claims

1. A solenoid valve comprising: a coil that provides a magnetic field when the coil is energized;a stator core that includes a receiving bore, wherein the stator core generates a magnetic attractive force when the coil is energized;a valve member that is attracted toward the stator core due to the magnetic attractive force generated by the stator core;a coil spring that is received in the receiving bore of the stator core, wherein the coil spring biases the valve member in an opposite direction opposite from the stator core; anda stopper that positions the coil spring such that an outer peripheral surface of the coil spring is separated from an inner peripheral surface of the receiving bore.

2. The valve according to claim 1, wherein: the stopper includes: a first portion at one side of the stopper closer to an end portion of the receiving bore;a second portion that extends from the first portion toward the valve member;the second portion has a cross sectional area smaller than that of the first portion;the coil spring is provided on an outer peripheral side of the second portion;one longitudinal end of the coil spring is supported by the first portion; andthe other longitudinal end of the coil spring is supported by the valve member.

3. The valve according to claim 2, wherein: the valve member is configured to contact the second portion when the valve member is attracted toward the stator core such that movement of the valve member toward the stator core is limited.

4. The valve according to claim 2, further comprising: a shim that is provided between the one longitudinal end of the coil spring and the first portion.

5. The valve according to claim 3, further comprising: a shim that is provided between the end portion of the receiving bore and the first portion.

6. The valve according to claim 1, wherein: Dsc−Dcs1>(Dsc−Dst1)+(Dcs2−Dst2) is satisfied in a condition where:the receiving bore has an inner diameter of Dsc;the first portion has an outer diameter of Dst1;the second portion has an outer diameter of Dst2;the coil spring has an outer diameter of Dcs1; andthe coil spring has an inner diameter of Dcs2.

7. The valve according to claim 2, wherein: the second portion includes a narrowing portion, a cross sectional area of which becomes smaller toward the valve member, on a side of the second portion closer to the valve member.

8. The valve according to claim 1, wherein: the stopper is made of a non-magnetic material.

9. The valve according to claim 4, wherein the shim provided between the one longitudinal end of the coil spring and the first portion is a first shim, the valve further comprising: a second shim that is provided between the end portion of the receiving bore and the first portion.